Tuning the coordination atoms of central metal is an effective means to improve the electrocatalytic activity of atomic catalysts.Herein,iridium(Ir) is proposed to be asymmetrically anchored by sp-N and pyridinic N of...Tuning the coordination atoms of central metal is an effective means to improve the electrocatalytic activity of atomic catalysts.Herein,iridium(Ir) is proposed to be asymmetrically anchored by sp-N and pyridinic N of hydrogen-substituted graphdiyne(HsGDY),and coordinated with OH as an Ir atomic catalyst(Ir_(1)-N-HsGDY).The electron structures,especially the d-band center of Ir atom,are optimized by these specific coordination atoms.Thus,the as-synthesized Ir_(1)-N-HsGDY exhibits excellent electrocatalytic performances for oxygen reduction and hydrogen evolution reactions in both acidic and alkaline media.Benefiting from the unique structure of HsGDY,IrN_(2)(OH)_(3) has been developed and demonstrated to act as the active site in these electrochemical reactions.All those indicate the fresh role of the sp-N in graphdiyne in producing a new anchor way and contributing to promote the electrocatalytic activity,showing a new strategy to design novel electrochemical catalysts.展开更多
Since the D-band center theory was proposed,it has been widely used in the fields of surface chemistry by almost all researchers,due to its easy understanding,convenient operation and relative accuracy.However,with th...Since the D-band center theory was proposed,it has been widely used in the fields of surface chemistry by almost all researchers,due to its easy understanding,convenient operation and relative accuracy.However,with the continuous development of material systems and modification strategies,researchers have gradually found that D-band center theory is usually effective for large metal particle systems,but for small metal particle systems or semiconductors,such as single atom systems,the opposite conclusion to the D-band center theory is often obtained.To solve the issue above,here we propose a bonding and anti-bonding orbitals stable electron intensity difference(BASED)theory for surface chemistry.The newly-proposed BASED theory can not only successfully explain the abnormal phenomena of D-band center theory,but also exhibits a higher accuracy for prediction of adsorption energy and bond length of intermediates on active sites.Importantly,a new phenomenon of the spin transition state in the adsorption process is observed based on the BASED theory,where the active center atom usually yields an unstable high spin transition state to enhance its adsorption capability in the adsorption process of intermediates when their distance is about 2.5Å.In short,the BASED theory can be considered as a general principle to understand catalytic mechanism of intermediates on surfaces.展开更多
The modulating effects of Cu modification and oxalate or borohydride ligands functionalization on the structure,catalyst d-band center(εd),upper d-band edge(εu),and acetylene partial hydrogenation of expediently syn...The modulating effects of Cu modification and oxalate or borohydride ligands functionalization on the structure,catalyst d-band center(εd),upper d-band edge(εu),and acetylene partial hydrogenation of expediently synthesized Ce alloyed Pt supported catalysts were investigated.Firstly,a 5 wt%Pt alloyed Ce was synthesized via flame spray pyrolysis.The PtCe sample was further supported on zeolite Y,ZY,(PtCe/ZY)and copper modified ZY(PtCe/Cu-ZY).Furthermore,the PtCe was supported on two other oxalate and borohydride ligands functionalized copper modified ZY(PtCe/CuX-ZY and PtCe/CuB-ZY,respectively).The high-angle annular darkfield scanning transmission electron microscopy(HAADF/STEM)data showed a reduction in the PtO average particle size from 2.65 nm in PtCeO_(2) to average 1.73,0.64,and 0.30 nm in PtCe/Cu-ZY,PtCe/CuX-ZY,and PtCe/CuB-ZY,which was corroborated by the electron energy-loss spectroscopy(EELS)results wherein nonhomogeneous mixing of elements was seen with segregated Pt clusters in the non-functionalized samples.Conversely,both PtCe/CuX-ZY and PtCe/CuBZY samples showed near-perfect homogeneity with no distinct Pt signals.The measuredεu values for PtCe,PtCe/Cu-ZY,PtCe/CuX-ZY,and PtCe/CuB-ZY are+1.85,+0.40,-0.15,and-0.19 eV,respectively.The positive values indicated strong metal-adsorbate bonding typical of large Pt sizes while the negative values indicated weak metal-adsorbate bonding due to highly downsized Pt sizes.The ethylene yield(YC2H4)over the PtCe sample showed depletion as the reaction temperature increased,while it reflected maxima at 120℃ with 55.3%YC2H4 over PtCe/ZY.The maxima shifted to 180℃ with enhanced YC2H4 of 71.4%in PtCe/Cu-ZY.On the contrary,both PtCe/CuX-ZY and PtCe/CuB-ZY exhibited a monotonous increase in YC2H4 up to the maximum C_(2)H_(2)conversion with YC2H4 of 81.9%and 92.1%at 180 and 160℃,respectively.These results showed that both the Cu modification and ligands functionalization were highly invaluable to enhance the properties and activities of the semihydrogenation of acetylene(SHA)catalysts.展开更多
Photoreduction of CO_(2) to solar fuels has caused great interest,but suffers from low catalytic efficiency and poor selectivity.Herein,we designed a S-scheme heterojunction(Cu-TiO_(2)/WO_(3))with Cu single atom to si...Photoreduction of CO_(2) to solar fuels has caused great interest,but suffers from low catalytic efficiency and poor selectivity.Herein,we designed a S-scheme heterojunction(Cu-TiO_(2)/WO_(3))with Cu single atom to significantly boost the photoreduction of CO_(2).Notably,the developed Cu-TiO_(2)/WO_(3) achieved the solardriven conversion of CO_(2) to CH_(4) with an evolution rate of 98.69μmol g^(−1) h^(−1),and the electron selectivity of CH_(4) reached 88.5%.The yield was much higher than those of pristine WO_(3),TiO_(2)/WO_(3) and Cu-TiO_(2) samples.Experimental and theoretical analysis suggested that the S-scheme heterojunction accelerated charge migration and inhibited the recombination of electron-hole pairs.Importantly,the charge separation effect of the heterojunction meliorated the position of the d-band.The uplifted d-band centers of Cu and Ti on Cu-TiO_(2)/WO_(3) not only improved the electron interaction between Cu single atoms and substrate-TiO_(2),accelerated the adsorption and activation of CO_(2) on the active sites of Cu single atom,but also optimized the Gibbs free energies of CH 4 formation pathway,leading to excellent selectivity toward CH_(4).This work provides new insights into the design of photocatalyst systems with high photocatalytic performance.展开更多
After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordinati...After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordination,spatial configuration,and metal–metal atom interaction hinder the development and design of SAzymes.Herein,a dual-centered Fe-Cu-N_(x)SAzyme exhibits excellent peroxidase(POD)-and catalase(CAT)-like activities with d-band center(ε_(d))coordination of Fe and Cu in multiple reaction stages,which plays a critical role in the adsorption of H_(2)O_(2)molecule and H_(2)O and O_(2)release.Therefore,the dband center coordination,which can be represented byε_(d)(Fe)–ε_(d)(Cu)shifts,leads to the competition between one-side and bilateral adsorption,which determines the favorable reaction path with lower energy barriers.Based on experimental statistics,simulated formation energies,and reaction barriers,3 configurations,Fe-Cu-N6-I,Fe-Cu-N_(8)-II,and Fe-Cu-N_(8)-III,are modeled and validated.Impressively,configuration-dependent catalytic selectivity and the competition between one-side and bilateral adsorption can be unveiled by d-band center coordination paradigm analysis.Theoretical simulations suggest that the unsymmetrical charge distribution over the three Fe-Cu configurations could tune the adsorption strength compared with the counterparts FeN_(4)and CuN_(4).The present work provides a potential route for optimizing enzyme-like catalysis by designing the dual-or even triple-metal SAzymes,which demonstrates the large space to modulate the metal atomic configuration and interaction.展开更多
The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate the...The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate them to analyze their selectivity in ethanol oxidation reaction(EOR).Here,Pt1Au1alloy supported on the commercial carbon material(Pt_(1)Au_(1)/C)is employed as a typical example to investigate its d-band center shift of surface Pt,and as electrocatalysts to study its selectivity towards EOR.Significantly,a highly reliable in situ Fourier-transform infrared spectroscopy CO-probe strategy is developed to characterize the d-band center shift of surface Pt.The modified electronic effect and site effect of Pt_(1)Au_(1)/C dictated the adsorption configuration of intermediate species and the OH species coverage,thereby influencing its selectivity.More importantly,we developed a universal cyclic voltammetry peak differentiation fitting method as an electrochemical analysis technique to investigate CO_(2)selectivity,which is potentially extendable to other Pt-based electrocatalysts.展开更多
Attaining a highly efficient and inexpensive electrocatalyst is significant for the hydrogen evolution reaction(HER)but still challenging nowadays.The transition-metal phosphides(TMPs)catalysts with platinum-like elec...Attaining a highly efficient and inexpensive electrocatalyst is significant for the hydrogen evolution reaction(HER)but still challenging nowadays.The transition-metal phosphides(TMPs)catalysts with platinum-like electronic structures are a potential candidate for the HER,but those are prone to be strongly bound with hydrogen intermediates(H∗),resulting in sluggish HER kinetics.Herein we report a unique hybrid structure of CoP anchored on graphene nanoscrolls@carbon nano tubes(CNTs)scaffold(Ni M@C-CoP)encapsulating various Ni M(M=Zn,Mo,Ni,Co)bimetal nanoalloy via chemical vapor deposi-tion(CVD)growth of CNT on graphene nanoscrolls followed by the impregnation of cobalt precursors and phosphorization for efficiently electrocatalytic hydrogen evolution.CoP nanoparticles mainly scattered at the tip of CNT branches which exhibited the analogical“Three-layer core-shell”structures.Experiments and density functional theory(DFT)calculations consistently disclose that the encapsulated various NiMs can offer different numbers of electrons to weaken the interactions of outmost CoP with H∗and push the downshift of the d-band center to different degrees as well as stabilize the outmost CoP nanopar-ticles to gain catalytic stability via the electron traversing effect.The electrocatalytic HER activity can be maximumly enhanced with low overpotentials of 78 mV(alkaline)and 89 mV(acidic)at a current density of 10 mA/cm^(2) and sustained at least 24 h especially for NiZn@C-CoP catalyst.This novel system is distinct from conventional three-layer heterostructure,providing a specially thought of d-band center control engineering strategy for the design of heterogeneous catalysts and expanding to other electrocat-alysts,energy storage,sensing,and other applications.展开更多
The d-band centers of catalysts have exhibited excellent performance in various reactions.Among them,the enhanced catalytic reaction is considered a crucial way to power dynamics and reduce the“shuttle”effect in pol...The d-band centers of catalysts have exhibited excellent performance in various reactions.Among them,the enhanced catalytic reaction is considered a crucial way to power dynamics and reduce the“shuttle”effect in polysulfide conversions of lithium-sulfur batteries.Here,we report two-dimensional-shaped tungsten borides(WB)nanosheets with d-band centers,where the d orbits of W atoms on the(001)facets show greatly promoting the electrocatalytic sulfur reduction reaction.As-prepared WB-based Li-S cells exhibit excellent electrochemical performance for Li-ion storage.Especially,it delivers superior capacities of 7.7 mAh/cm^(2) under the 8.0 mg/cm^(2) sulfur loading,which is far superior to most other electrode catalysts.This study provides insights into the d-band centers as a promising catalyst of twodimensional boride materials.展开更多
Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electro...Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electronic configuration in valley bottom exhibits inert activity,which seriously fetters the development of catalytic materials with great potentials.Herein,In d^(10)electronic configuration of In_(2)O_(3)was activated by phosphorus atoms replacing its lattice oxygen to regulate the collocation of the ascended In 5p-band(Inɛ5p)and descended O 2p-band(Oɛ2p)centers as efficient active sites for chemisorption to*OH and*H during forward HOS,respectively,along with a declined In 4d-band center(Inɛ4d)to inhibit its backward reaction.A stable STH efficiency of 2.23%under AM 1.5 G irradiation at 65°C has been obtained over the activated d^(10)electronic configuration with a lowered activation energy for H_(2)evolution,verified by femtosecond transient absorption spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations of dynamics.These findings devote to activating d^(10)electronic configuration for resolving the reaction energy barrier and dynamical bottleneck of forward HOS,which expands the exploration of high-efficiency catalytic materials.展开更多
Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,...Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in mice.The cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)proteins.The cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).展开更多
A nanodiamond with an embedded nitrogen-vacancy(NV)center is one of the experimental systems that can be coherently manipulated within current technologies.Entanglement between NV center electron spin and mechanical r...A nanodiamond with an embedded nitrogen-vacancy(NV)center is one of the experimental systems that can be coherently manipulated within current technologies.Entanglement between NV center electron spin and mechanical rotation of the nanodiamond plays a fundamental role in building a quantum network connecting these microscopic and mesoscopic degrees of motions.Here we present a protocol to asymptotically prepare a highly entangled state of the total quantum angular momentum and electron spin by adiabatically boosting the external magnetic field.展开更多
Method: In Cameroon limited data are available regarding the prevalence of enteric bacteria associated with table egg consuming infections. As such, a situational-based study was performed in patients with complains o...Method: In Cameroon limited data are available regarding the prevalence of enteric bacteria associated with table egg consuming infections. As such, a situational-based study was performed in patients with complains of stomach disorders after egg consumption. Data related to sociodemographic characteristics and other factors were collected using a structured based questionnaire. Stool culture of utmost importance in stomach disorders patients and serum were collected for typhoid serological test. Results: A total of 207 participants took part in the survey, Results indicated nontyphoidal Salmonella infections were highest in the 3 areas of study with Mfoundi (73.44%) having the highest level of infection compared to other bacterial infection. other enteric bacteria associated to this infection were E. coli serotype 157, Aeromonas, Citrobacter freundii, Enterobacter cloaca and typhi salmonella. Meanwhile salmonelosis caused by typhic salmonella had highest prevalence in the Lekie Division (13.11%) as a result of poor hygienic practices associated with the conservation and preparation of eggs, Stool culture was observed to detect more positive cases in the diagnosis of typhoid fever than Widal test, but with no statistically significant (p > 0.05) difference between the stool culture and Widal test in the 3 areas of study. Conclusion: this study revealed that egg consumers are pruned to enteric bacterial and salmonella infections depending on how and where egg is consumed.展开更多
Background: Pacemaker implantation is a very old activity which has revolutionized the cardiology practice throughout the world. This activity is effective at the Haute Correze Hospital Center since more than 20 years...Background: Pacemaker implantation is a very old activity which has revolutionized the cardiology practice throughout the world. This activity is effective at the Haute Correze Hospital Center since more than 20 years. Due to progress in this area, and the increasing request within this center located at the outskirts of town, we set out to evaluate our pacemaker activity in general and more specifically to assess the post-procedural complications in our series patients. Methodology: This was a retrospective longitudinal study. Data were recorded for period of 90 months from 27/05/2016 to 19/11/2023. This data collection was possible via a specific register completed by computerized patient data from the SillageTM software. All files of patients implanted with single or dual chamber pacemakers were included, generator replacements, upgrading procedures and addition of leads were excluded. The sampling was non-probabilistic, consecutive and non-exhaustive. Statistical analysis was carried out using the Excel 2019 spreadsheet and SPSS version 23 software. The quantitative variables were presented as mean ± standard deviation, the qualitative data as proportions. Results: A total of 303 first-time pacemaker’s implantations were carried out during the study period (rate of 40 per year). The average age in the population was 79.7 ± 9.4 years (44 - 99 years) with a male predominance of 63.7% (n = 193). Atrioventricular block (2nd and 3rd degree) was the main indication for pacemaker implantation in 42.9% of cases (n = 130). Patients were most often implanted with a dual-chamber pacemaker (57.7%, n = 175). The approach was most often cephalic in 72.6% of cases (n = 220), followed by the subclavian access in 27.4% of cases (n = 84). The average fluoroscopy time was 7.9 min ± 2.4 (1 - 43). The average irradiation dose in gray/cm2 was 12.4 ± 9.3 (0.22 - 117.5). The average length of hospitalization was 7 ± 4 (2 - 26) days. The overall complication rate at one year was 12.9% (n = 39). These complications are distributed as follows: Leads dislodgement in 8.2% (n = 25), hematoma 3.6% (n = 11) all without clinical consequences, pneumothorax 0.7% (n = 2), both cases of pneumothorax did not require specific care, infection (superficial) in 0.3% (n = 1). Leads dislodgement occurred after a median time of 18 days (IQR: 3 - 36). The earliest dislodgement was observed on D0 and the latest on D207. No serious complications were recorded. The average atrial threshold at implantation/first control/last follow-up was 0.7/1.3/0.8 V, respectively. The average ventricular threshold at implantation/first control/last follow-up was 0.5/1.08/0.87 V, respectively. The average atrial detection at implantation/first control/last follow-up was 3.2/2.3/ 2.05 mv, respectively. The average ventricular detection at implantation/first control/last follow-up was 10.3/11.03/10.8 mv. The average atrial impedance at implantation/first control/last follow-up was 610/457/457 ohms. The average ventricular impedance at implantation/first control/last follow-up was 754/547/563 ohms. Conclusion: Pacemaker implantation is safe at the Haute Correze Hospital Center with a relatively low rate of complications, in this case an almost zero major infection and no serious hematoma. The peripheral hospital should remain a focal point of this activity in order to respond more quickly to the needs of the populations.展开更多
To the Editor:We read with great interest the article by Schulze et al.entitled“Robotic surgery and liver transplantation:A single-center experience of 501 robotic donor hepatectomies”[1].It is the first single-cent...To the Editor:We read with great interest the article by Schulze et al.entitled“Robotic surgery and liver transplantation:A single-center experience of 501 robotic donor hepatectomies”[1].It is the first single-center report including over 500 fully robotic donor hepatectomies.For the donors,the overall complication rate was 6.4%(n=32).Postoperative self-limiting bleeding(0.4%)and bile leakage from the resection plane(1.8%)were rare.展开更多
The 6th generation mobile networks(6G)network is a kind of multi-network interconnection and multi-scenario coexistence network,where multiple network domains break the original fixed boundaries to form connections an...The 6th generation mobile networks(6G)network is a kind of multi-network interconnection and multi-scenario coexistence network,where multiple network domains break the original fixed boundaries to form connections and convergence.In this paper,with the optimization objective of maximizing network utility while ensuring flows performance-centric weighted fairness,this paper designs a reinforcement learning-based cloud-edge autonomous multi-domain data center network architecture that achieves single-domain autonomy and multi-domain collaboration.Due to the conflict between the utility of different flows,the bandwidth fairness allocation problem for various types of flows is formulated by considering different defined reward functions.Regarding the tradeoff between fairness and utility,this paper deals with the corresponding reward functions for the cases where the flows undergo abrupt changes and smooth changes in the flows.In addition,to accommodate the Quality of Service(QoS)requirements for multiple types of flows,this paper proposes a multi-domain autonomous routing algorithm called LSTM+MADDPG.Introducing a Long Short-Term Memory(LSTM)layer in the actor and critic networks,more information about temporal continuity is added,further enhancing the adaptive ability changes in the dynamic network environment.The LSTM+MADDPG algorithm is compared with the latest reinforcement learning algorithm by conducting experiments on real network topology and traffic traces,and the experimental results show that LSTM+MADDPG improves the delay convergence speed by 14.6%and delays the start moment of packet loss by 18.2%compared with other algorithms.展开更多
Introduction: Malnutrition is a pathological state resulting from the relative deficiency or excess of one or more essential nutrients, whether manifested clinically or detected only by biochemical, anthropometric or ...Introduction: Malnutrition is a pathological state resulting from the relative deficiency or excess of one or more essential nutrients, whether manifested clinically or detected only by biochemical, anthropometric or physiological analyses. The overall objective was to assess the quality of management of acute malnutrition in children aged 0 - 24 months at the Boulbinet health center. Methodology: This was a prospective descriptive study lasting six (06) months from May 5 to October 5, 2018. The study included all children aged 0 to 24 months. Results: Acute malnutrition in children aged 0 - 24 months accounted for 2.11% of cases. The sex ratio was 1.41 in favor of males. The mean age of our patients was 5 months 7 days, with extremes of 1 month and 6 months. The majority came from Ra toma (40.24%). Exclusive breastfeeding was most common (54.02%). The main clinical signs were: pallor 49.42%, diarrhea 46.67, oral lesions37.96%. SAM represented 89.66% and MAM 10.34%. Most associated pathologies: anemia 49.42% and oral candidiasis 37.93%. In terms of outcome, we recorded 56.32% cures, 20.69% deaths, 18.39% dropouts and 4.60% cures. Conclusion: Improving the quality of care for malnourished children aged 0 - 24 months requires raising awareness among mothers and the general public of the consequences of malnutrition.展开更多
Entanglement in macroscopic systems,as a fundamental quantum resource,has been utilized to propel the advancement of quantum technology and probe the boundary between the quantum and classical realms.This study focuse...Entanglement in macroscopic systems,as a fundamental quantum resource,has been utilized to propel the advancement of quantum technology and probe the boundary between the quantum and classical realms.This study focuses on a unique hybrid quantum system comprising of an ensemble of silicon vacancy(SiV)centers coupled to phononic waveguides in diamond via strain interactions.By employing two sets of time-dependent,non-overlapping driving fields,we investigate the generation process and dynamic properties of macroscopic quantum entanglement,providing fresh insights into the behavior of such hybrid quantum systems.Furthermore,it paves the way for new possibilities in utilizing quantum entanglement as an information carrier in quantum information processing and quantum communication.展开更多
The traffic within data centers exhibits bursts and unpredictable patterns.This rapid growth in network traffic has two consequences:it surpasses the inherent capacity of the network’s link bandwidth and creates an i...The traffic within data centers exhibits bursts and unpredictable patterns.This rapid growth in network traffic has two consequences:it surpasses the inherent capacity of the network’s link bandwidth and creates an imbalanced network load.Consequently,persistent overload situations eventually result in network congestion.The Software Defined Network(SDN)technology is employed in data centers as a network architecture to enhance performance.This paper introduces an adaptive congestion control strategy,named DA-DCTCP,for SDN-based Data Centers.It incorporates Explicit Congestion Notification(ECN)and Round-Trip Time(RTT)to establish congestion awareness and an ECN marking model.To mitigate incorrect congestion caused by abrupt flows,an appropriate ECN marking is selected based on the queue length and its growth slope,and the congestion window(CWND)is adjusted by calculating RTT.Simultaneously,the marking threshold for queue length is continuously adapted using the current queue length of the switch as a parameter to accommodate changes in data centers.The evaluation conducted through Mininet simulations demonstrates that DA-DCTCP yields advantages in terms of throughput,flow completion time(FCT),latency,and resistance against packet loss.These benefits contribute to reducing data center congestion,enhancing the stability of data transmission,and improving throughput.展开更多
Phosphate removal is crucial for eutrophication control and water quality improvement.Electro-assisted adsorption,an eco-friendly elec-trosorption process,exhibited a promising potential for wastewater treatment.Howev...Phosphate removal is crucial for eutrophication control and water quality improvement.Electro-assisted adsorption,an eco-friendly elec-trosorption process,exhibited a promising potential for wastewater treatment.However,there are few works focused on phosphate electro-sorption,and reported electrodes cannot attach satisfactory removal capacities and rates.Herein,electro-assisted adsorption of phosphate via in-situ construction of La active centers on hierarchically porous carbon(LaPC)has been originally demonstrated.The resulted LaPC composite not only possessed a hierarchically porous structure with uniformly dispersed La active sites,but also provided good conductivity for interfacial electron transfer.The LaPC electrode achieved an ultrahigh phosphate electrosorption capability of 462.01 mg g^(-1) at 1 V,outperforming most existing electrodes.The superior phosphate removal performance originates from abundant active centers formed by the coupling of electricfield and capture sites.Besides,the stability and selectivity toward phosphate capture were maintained well even under comprehensive conditions.Moreover,a series of kinetics and isotherms models were employed to validate the electrosorption process.This work demonstrates a deep understanding and promotes a new level of phosphate electrosorption.展开更多
An integrated quantum probe for magnetic field imaging is proposed,where the nitrogen–vacancy(NV)center fixed at the fiber tip is located on the periphery of flexible ring resonator.Using flexible polyimide(PI)as the...An integrated quantum probe for magnetic field imaging is proposed,where the nitrogen–vacancy(NV)center fixed at the fiber tip is located on the periphery of flexible ring resonator.Using flexible polyimide(PI)as the substrate medium,we design a circular microstrip antenna,which can achieve a bandwidth of 140 MHz at Zeeman splitting frequency of 2.87 GHz,specifically suitable for NV center experiments.Subsequently,this antenna is seamlessly fixed at a three-dimensional-printed cylindrical support,allowing the optical fiber tip to extend out of a dedicated aperture.To mitigate errors originating from processing,precise tuning within a narrow range can be achieved by adjusting the conformal amplitude.Finally,we image the microwave magnetic field around the integrated probe with high resolution,and determine the suitable area for placing the fiber tip(SAP).展开更多
基金supported by the National Natural Science Foundation of China(22172090,21790051)the National Key Research and Development Project of China(2022YFA1204500,2022YFA1204501)+2 种基金the Natural Science Foundation of Shan-dong Province(ZR2021MB015)the Open Funds of the State Key Laboratory of Electroanalytical Chemistry(SKLEAC202202)the Young Scholars Program of Shandong University。
文摘Tuning the coordination atoms of central metal is an effective means to improve the electrocatalytic activity of atomic catalysts.Herein,iridium(Ir) is proposed to be asymmetrically anchored by sp-N and pyridinic N of hydrogen-substituted graphdiyne(HsGDY),and coordinated with OH as an Ir atomic catalyst(Ir_(1)-N-HsGDY).The electron structures,especially the d-band center of Ir atom,are optimized by these specific coordination atoms.Thus,the as-synthesized Ir_(1)-N-HsGDY exhibits excellent electrocatalytic performances for oxygen reduction and hydrogen evolution reactions in both acidic and alkaline media.Benefiting from the unique structure of HsGDY,IrN_(2)(OH)_(3) has been developed and demonstrated to act as the active site in these electrochemical reactions.All those indicate the fresh role of the sp-N in graphdiyne in producing a new anchor way and contributing to promote the electrocatalytic activity,showing a new strategy to design novel electrochemical catalysts.
文摘Since the D-band center theory was proposed,it has been widely used in the fields of surface chemistry by almost all researchers,due to its easy understanding,convenient operation and relative accuracy.However,with the continuous development of material systems and modification strategies,researchers have gradually found that D-band center theory is usually effective for large metal particle systems,but for small metal particle systems or semiconductors,such as single atom systems,the opposite conclusion to the D-band center theory is often obtained.To solve the issue above,here we propose a bonding and anti-bonding orbitals stable electron intensity difference(BASED)theory for surface chemistry.The newly-proposed BASED theory can not only successfully explain the abnormal phenomena of D-band center theory,but also exhibits a higher accuracy for prediction of adsorption energy and bond length of intermediates on active sites.Importantly,a new phenomenon of the spin transition state in the adsorption process is observed based on the BASED theory,where the active center atom usually yields an unstable high spin transition state to enhance its adsorption capability in the adsorption process of intermediates when their distance is about 2.5Å.In short,the BASED theory can be considered as a general principle to understand catalytic mechanism of intermediates on surfaces.
文摘The modulating effects of Cu modification and oxalate or borohydride ligands functionalization on the structure,catalyst d-band center(εd),upper d-band edge(εu),and acetylene partial hydrogenation of expediently synthesized Ce alloyed Pt supported catalysts were investigated.Firstly,a 5 wt%Pt alloyed Ce was synthesized via flame spray pyrolysis.The PtCe sample was further supported on zeolite Y,ZY,(PtCe/ZY)and copper modified ZY(PtCe/Cu-ZY).Furthermore,the PtCe was supported on two other oxalate and borohydride ligands functionalized copper modified ZY(PtCe/CuX-ZY and PtCe/CuB-ZY,respectively).The high-angle annular darkfield scanning transmission electron microscopy(HAADF/STEM)data showed a reduction in the PtO average particle size from 2.65 nm in PtCeO_(2) to average 1.73,0.64,and 0.30 nm in PtCe/Cu-ZY,PtCe/CuX-ZY,and PtCe/CuB-ZY,which was corroborated by the electron energy-loss spectroscopy(EELS)results wherein nonhomogeneous mixing of elements was seen with segregated Pt clusters in the non-functionalized samples.Conversely,both PtCe/CuX-ZY and PtCe/CuBZY samples showed near-perfect homogeneity with no distinct Pt signals.The measuredεu values for PtCe,PtCe/Cu-ZY,PtCe/CuX-ZY,and PtCe/CuB-ZY are+1.85,+0.40,-0.15,and-0.19 eV,respectively.The positive values indicated strong metal-adsorbate bonding typical of large Pt sizes while the negative values indicated weak metal-adsorbate bonding due to highly downsized Pt sizes.The ethylene yield(YC2H4)over the PtCe sample showed depletion as the reaction temperature increased,while it reflected maxima at 120℃ with 55.3%YC2H4 over PtCe/ZY.The maxima shifted to 180℃ with enhanced YC2H4 of 71.4%in PtCe/Cu-ZY.On the contrary,both PtCe/CuX-ZY and PtCe/CuB-ZY exhibited a monotonous increase in YC2H4 up to the maximum C_(2)H_(2)conversion with YC2H4 of 81.9%and 92.1%at 180 and 160℃,respectively.These results showed that both the Cu modification and ligands functionalization were highly invaluable to enhance the properties and activities of the semihydrogenation of acetylene(SHA)catalysts.
基金supported by the grants from the National Natural Science Foundation of China(Nos.21872102 and 22172080)the Tianjin“Project+Team”innovation team,2020.
文摘Photoreduction of CO_(2) to solar fuels has caused great interest,but suffers from low catalytic efficiency and poor selectivity.Herein,we designed a S-scheme heterojunction(Cu-TiO_(2)/WO_(3))with Cu single atom to significantly boost the photoreduction of CO_(2).Notably,the developed Cu-TiO_(2)/WO_(3) achieved the solardriven conversion of CO_(2) to CH_(4) with an evolution rate of 98.69μmol g^(−1) h^(−1),and the electron selectivity of CH_(4) reached 88.5%.The yield was much higher than those of pristine WO_(3),TiO_(2)/WO_(3) and Cu-TiO_(2) samples.Experimental and theoretical analysis suggested that the S-scheme heterojunction accelerated charge migration and inhibited the recombination of electron-hole pairs.Importantly,the charge separation effect of the heterojunction meliorated the position of the d-band.The uplifted d-band centers of Cu and Ti on Cu-TiO_(2)/WO_(3) not only improved the electron interaction between Cu single atoms and substrate-TiO_(2),accelerated the adsorption and activation of CO_(2) on the active sites of Cu single atom,but also optimized the Gibbs free energies of CH 4 formation pathway,leading to excellent selectivity toward CH_(4).This work provides new insights into the design of photocatalyst systems with high photocatalytic performance.
基金supported by the National Key Research and Development Program of China(Nos.2021YFF1200700 and 2021YFF1200701)the National Natural Science Foundation of China(Nos.91859101,81971744,U1932107,82001952,11804248,82302361,and 82302381)+5 种基金Outstanding Youth Funds of Tianjin(No.2021FJ-0009)STI 2030-Major Projects(No.2022ZD0210200)National Natural Science Foundation of Tianjin(Nos.19JCZDJC34000,20JCYBJC00940,21JCYBJC00550,21JCZDJC00620,and 21JCYBJC00490)the Key Projects of Tianjin Natural Fund(No.21JCZDJC00490)the Innovation Foundation of Tianjin University,China Postdoctoral Science Foundation(No.2023M732601)CAS Interdisciplinary Innovation Team(No.JCTD-2020-08).
文摘After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordination,spatial configuration,and metal–metal atom interaction hinder the development and design of SAzymes.Herein,a dual-centered Fe-Cu-N_(x)SAzyme exhibits excellent peroxidase(POD)-and catalase(CAT)-like activities with d-band center(ε_(d))coordination of Fe and Cu in multiple reaction stages,which plays a critical role in the adsorption of H_(2)O_(2)molecule and H_(2)O and O_(2)release.Therefore,the dband center coordination,which can be represented byε_(d)(Fe)–ε_(d)(Cu)shifts,leads to the competition between one-side and bilateral adsorption,which determines the favorable reaction path with lower energy barriers.Based on experimental statistics,simulated formation energies,and reaction barriers,3 configurations,Fe-Cu-N6-I,Fe-Cu-N_(8)-II,and Fe-Cu-N_(8)-III,are modeled and validated.Impressively,configuration-dependent catalytic selectivity and the competition between one-side and bilateral adsorption can be unveiled by d-band center coordination paradigm analysis.Theoretical simulations suggest that the unsymmetrical charge distribution over the three Fe-Cu configurations could tune the adsorption strength compared with the counterparts FeN_(4)and CuN_(4).The present work provides a potential route for optimizing enzyme-like catalysis by designing the dual-or even triple-metal SAzymes,which demonstrates the large space to modulate the metal atomic configuration and interaction.
基金granted by the National Natural Science Foundation of China(22172134,22288102,22279011)Fundamental Research Funds for the Central Universities(2022CDJXY-003)。
文摘The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate them to analyze their selectivity in ethanol oxidation reaction(EOR).Here,Pt1Au1alloy supported on the commercial carbon material(Pt_(1)Au_(1)/C)is employed as a typical example to investigate its d-band center shift of surface Pt,and as electrocatalysts to study its selectivity towards EOR.Significantly,a highly reliable in situ Fourier-transform infrared spectroscopy CO-probe strategy is developed to characterize the d-band center shift of surface Pt.The modified electronic effect and site effect of Pt_(1)Au_(1)/C dictated the adsorption configuration of intermediate species and the OH species coverage,thereby influencing its selectivity.More importantly,we developed a universal cyclic voltammetry peak differentiation fitting method as an electrochemical analysis technique to investigate CO_(2)selectivity,which is potentially extendable to other Pt-based electrocatalysts.
基金This work was supported by the Science and Technology Pro-gram of Shaanxi Province(No.2019GY-200).Shengwu Guo and Wei Wang contributed to the material TEM and SEM characterizations in this work.
文摘Attaining a highly efficient and inexpensive electrocatalyst is significant for the hydrogen evolution reaction(HER)but still challenging nowadays.The transition-metal phosphides(TMPs)catalysts with platinum-like electronic structures are a potential candidate for the HER,but those are prone to be strongly bound with hydrogen intermediates(H∗),resulting in sluggish HER kinetics.Herein we report a unique hybrid structure of CoP anchored on graphene nanoscrolls@carbon nano tubes(CNTs)scaffold(Ni M@C-CoP)encapsulating various Ni M(M=Zn,Mo,Ni,Co)bimetal nanoalloy via chemical vapor deposi-tion(CVD)growth of CNT on graphene nanoscrolls followed by the impregnation of cobalt precursors and phosphorization for efficiently electrocatalytic hydrogen evolution.CoP nanoparticles mainly scattered at the tip of CNT branches which exhibited the analogical“Three-layer core-shell”structures.Experiments and density functional theory(DFT)calculations consistently disclose that the encapsulated various NiMs can offer different numbers of electrons to weaken the interactions of outmost CoP with H∗and push the downshift of the d-band center to different degrees as well as stabilize the outmost CoP nanopar-ticles to gain catalytic stability via the electron traversing effect.The electrocatalytic HER activity can be maximumly enhanced with low overpotentials of 78 mV(alkaline)and 89 mV(acidic)at a current density of 10 mA/cm^(2) and sustained at least 24 h especially for NiZn@C-CoP catalyst.This novel system is distinct from conventional three-layer heterostructure,providing a specially thought of d-band center control engineering strategy for the design of heterogeneous catalysts and expanding to other electrocat-alysts,energy storage,sensing,and other applications.
基金supported by the National Natural Science Foundation of China(Nos.61904080,22205101)the Natural Science Foundation of Jiangsu Province(No.BK20190670)+5 种基金the Natural Science Foundation of Colleges and Universities in Jiangsu Province(No.19KJB530008)the Macao Young Scholars Program(No.AM2020005)the High-Performance Computing Cluster(HPCC)of Information and Communication Technology Office(ICTO)at University of Macao,Science and Technology Development Fund,Macao SAR(Nos.0191/2017/A3,0041/2019/A1,0046/2019/AFJ,0021/2019/AIR)University of Macao(Nos.MYRG2017-00216-FST and MYRG2018-00192-IAPME),FDCT Funding Scheme for Postdoctoral Researchers(No.0026/APD/2021)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the UEA funding,and Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110994).
文摘The d-band centers of catalysts have exhibited excellent performance in various reactions.Among them,the enhanced catalytic reaction is considered a crucial way to power dynamics and reduce the“shuttle”effect in polysulfide conversions of lithium-sulfur batteries.Here,we report two-dimensional-shaped tungsten borides(WB)nanosheets with d-band centers,where the d orbits of W atoms on the(001)facets show greatly promoting the electrocatalytic sulfur reduction reaction.As-prepared WB-based Li-S cells exhibit excellent electrochemical performance for Li-ion storage.Especially,it delivers superior capacities of 7.7 mAh/cm^(2) under the 8.0 mg/cm^(2) sulfur loading,which is far superior to most other electrode catalysts.This study provides insights into the d-band centers as a promising catalyst of twodimensional boride materials.
文摘Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electronic configuration in valley bottom exhibits inert activity,which seriously fetters the development of catalytic materials with great potentials.Herein,In d^(10)electronic configuration of In_(2)O_(3)was activated by phosphorus atoms replacing its lattice oxygen to regulate the collocation of the ascended In 5p-band(Inɛ5p)and descended O 2p-band(Oɛ2p)centers as efficient active sites for chemisorption to*OH and*H during forward HOS,respectively,along with a declined In 4d-band center(Inɛ4d)to inhibit its backward reaction.A stable STH efficiency of 2.23%under AM 1.5 G irradiation at 65°C has been obtained over the activated d^(10)electronic configuration with a lowered activation energy for H_(2)evolution,verified by femtosecond transient absorption spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations of dynamics.These findings devote to activating d^(10)electronic configuration for resolving the reaction energy barrier and dynamical bottleneck of forward HOS,which expands the exploration of high-efficiency catalytic materials.
基金supported by R01 NS093009 grant from NIH(to VVC).
文摘Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in mice.The cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)proteins.The cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2021YFA0718302 and 2021YFA1402104)the National Natural Science Foundation of China(Grant No.12075310)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000).
文摘A nanodiamond with an embedded nitrogen-vacancy(NV)center is one of the experimental systems that can be coherently manipulated within current technologies.Entanglement between NV center electron spin and mechanical rotation of the nanodiamond plays a fundamental role in building a quantum network connecting these microscopic and mesoscopic degrees of motions.Here we present a protocol to asymptotically prepare a highly entangled state of the total quantum angular momentum and electron spin by adiabatically boosting the external magnetic field.
文摘Method: In Cameroon limited data are available regarding the prevalence of enteric bacteria associated with table egg consuming infections. As such, a situational-based study was performed in patients with complains of stomach disorders after egg consumption. Data related to sociodemographic characteristics and other factors were collected using a structured based questionnaire. Stool culture of utmost importance in stomach disorders patients and serum were collected for typhoid serological test. Results: A total of 207 participants took part in the survey, Results indicated nontyphoidal Salmonella infections were highest in the 3 areas of study with Mfoundi (73.44%) having the highest level of infection compared to other bacterial infection. other enteric bacteria associated to this infection were E. coli serotype 157, Aeromonas, Citrobacter freundii, Enterobacter cloaca and typhi salmonella. Meanwhile salmonelosis caused by typhic salmonella had highest prevalence in the Lekie Division (13.11%) as a result of poor hygienic practices associated with the conservation and preparation of eggs, Stool culture was observed to detect more positive cases in the diagnosis of typhoid fever than Widal test, but with no statistically significant (p > 0.05) difference between the stool culture and Widal test in the 3 areas of study. Conclusion: this study revealed that egg consumers are pruned to enteric bacterial and salmonella infections depending on how and where egg is consumed.
文摘Background: Pacemaker implantation is a very old activity which has revolutionized the cardiology practice throughout the world. This activity is effective at the Haute Correze Hospital Center since more than 20 years. Due to progress in this area, and the increasing request within this center located at the outskirts of town, we set out to evaluate our pacemaker activity in general and more specifically to assess the post-procedural complications in our series patients. Methodology: This was a retrospective longitudinal study. Data were recorded for period of 90 months from 27/05/2016 to 19/11/2023. This data collection was possible via a specific register completed by computerized patient data from the SillageTM software. All files of patients implanted with single or dual chamber pacemakers were included, generator replacements, upgrading procedures and addition of leads were excluded. The sampling was non-probabilistic, consecutive and non-exhaustive. Statistical analysis was carried out using the Excel 2019 spreadsheet and SPSS version 23 software. The quantitative variables were presented as mean ± standard deviation, the qualitative data as proportions. Results: A total of 303 first-time pacemaker’s implantations were carried out during the study period (rate of 40 per year). The average age in the population was 79.7 ± 9.4 years (44 - 99 years) with a male predominance of 63.7% (n = 193). Atrioventricular block (2nd and 3rd degree) was the main indication for pacemaker implantation in 42.9% of cases (n = 130). Patients were most often implanted with a dual-chamber pacemaker (57.7%, n = 175). The approach was most often cephalic in 72.6% of cases (n = 220), followed by the subclavian access in 27.4% of cases (n = 84). The average fluoroscopy time was 7.9 min ± 2.4 (1 - 43). The average irradiation dose in gray/cm2 was 12.4 ± 9.3 (0.22 - 117.5). The average length of hospitalization was 7 ± 4 (2 - 26) days. The overall complication rate at one year was 12.9% (n = 39). These complications are distributed as follows: Leads dislodgement in 8.2% (n = 25), hematoma 3.6% (n = 11) all without clinical consequences, pneumothorax 0.7% (n = 2), both cases of pneumothorax did not require specific care, infection (superficial) in 0.3% (n = 1). Leads dislodgement occurred after a median time of 18 days (IQR: 3 - 36). The earliest dislodgement was observed on D0 and the latest on D207. No serious complications were recorded. The average atrial threshold at implantation/first control/last follow-up was 0.7/1.3/0.8 V, respectively. The average ventricular threshold at implantation/first control/last follow-up was 0.5/1.08/0.87 V, respectively. The average atrial detection at implantation/first control/last follow-up was 3.2/2.3/ 2.05 mv, respectively. The average ventricular detection at implantation/first control/last follow-up was 10.3/11.03/10.8 mv. The average atrial impedance at implantation/first control/last follow-up was 610/457/457 ohms. The average ventricular impedance at implantation/first control/last follow-up was 754/547/563 ohms. Conclusion: Pacemaker implantation is safe at the Haute Correze Hospital Center with a relatively low rate of complications, in this case an almost zero major infection and no serious hematoma. The peripheral hospital should remain a focal point of this activity in order to respond more quickly to the needs of the populations.
文摘To the Editor:We read with great interest the article by Schulze et al.entitled“Robotic surgery and liver transplantation:A single-center experience of 501 robotic donor hepatectomies”[1].It is the first single-center report including over 500 fully robotic donor hepatectomies.For the donors,the overall complication rate was 6.4%(n=32).Postoperative self-limiting bleeding(0.4%)and bile leakage from the resection plane(1.8%)were rare.
文摘The 6th generation mobile networks(6G)network is a kind of multi-network interconnection and multi-scenario coexistence network,where multiple network domains break the original fixed boundaries to form connections and convergence.In this paper,with the optimization objective of maximizing network utility while ensuring flows performance-centric weighted fairness,this paper designs a reinforcement learning-based cloud-edge autonomous multi-domain data center network architecture that achieves single-domain autonomy and multi-domain collaboration.Due to the conflict between the utility of different flows,the bandwidth fairness allocation problem for various types of flows is formulated by considering different defined reward functions.Regarding the tradeoff between fairness and utility,this paper deals with the corresponding reward functions for the cases where the flows undergo abrupt changes and smooth changes in the flows.In addition,to accommodate the Quality of Service(QoS)requirements for multiple types of flows,this paper proposes a multi-domain autonomous routing algorithm called LSTM+MADDPG.Introducing a Long Short-Term Memory(LSTM)layer in the actor and critic networks,more information about temporal continuity is added,further enhancing the adaptive ability changes in the dynamic network environment.The LSTM+MADDPG algorithm is compared with the latest reinforcement learning algorithm by conducting experiments on real network topology and traffic traces,and the experimental results show that LSTM+MADDPG improves the delay convergence speed by 14.6%and delays the start moment of packet loss by 18.2%compared with other algorithms.
文摘Introduction: Malnutrition is a pathological state resulting from the relative deficiency or excess of one or more essential nutrients, whether manifested clinically or detected only by biochemical, anthropometric or physiological analyses. The overall objective was to assess the quality of management of acute malnutrition in children aged 0 - 24 months at the Boulbinet health center. Methodology: This was a prospective descriptive study lasting six (06) months from May 5 to October 5, 2018. The study included all children aged 0 to 24 months. Results: Acute malnutrition in children aged 0 - 24 months accounted for 2.11% of cases. The sex ratio was 1.41 in favor of males. The mean age of our patients was 5 months 7 days, with extremes of 1 month and 6 months. The majority came from Ra toma (40.24%). Exclusive breastfeeding was most common (54.02%). The main clinical signs were: pallor 49.42%, diarrhea 46.67, oral lesions37.96%. SAM represented 89.66% and MAM 10.34%. Most associated pathologies: anemia 49.42% and oral candidiasis 37.93%. In terms of outcome, we recorded 56.32% cures, 20.69% deaths, 18.39% dropouts and 4.60% cures. Conclusion: Improving the quality of care for malnourished children aged 0 - 24 months requires raising awareness among mothers and the general public of the consequences of malnutrition.
基金the National Natural Science Foundationof China (Grant No. 12265022)the Natural ScienceFoundation of Inner Mongolia Autonomous Region, China(Grant No. 2021MS01012)the Inner Mongolia FundamentalResearch Funds for the Directly Affiliated Universities(Grant No. 2023RCTD014).
文摘Entanglement in macroscopic systems,as a fundamental quantum resource,has been utilized to propel the advancement of quantum technology and probe the boundary between the quantum and classical realms.This study focuses on a unique hybrid quantum system comprising of an ensemble of silicon vacancy(SiV)centers coupled to phononic waveguides in diamond via strain interactions.By employing two sets of time-dependent,non-overlapping driving fields,we investigate the generation process and dynamic properties of macroscopic quantum entanglement,providing fresh insights into the behavior of such hybrid quantum systems.Furthermore,it paves the way for new possibilities in utilizing quantum entanglement as an information carrier in quantum information processing and quantum communication.
基金supported by the National Key R&D Program of China(No.2021YFB2700800)the GHfund B(No.202302024490).
文摘The traffic within data centers exhibits bursts and unpredictable patterns.This rapid growth in network traffic has two consequences:it surpasses the inherent capacity of the network’s link bandwidth and creates an imbalanced network load.Consequently,persistent overload situations eventually result in network congestion.The Software Defined Network(SDN)technology is employed in data centers as a network architecture to enhance performance.This paper introduces an adaptive congestion control strategy,named DA-DCTCP,for SDN-based Data Centers.It incorporates Explicit Congestion Notification(ECN)and Round-Trip Time(RTT)to establish congestion awareness and an ECN marking model.To mitigate incorrect congestion caused by abrupt flows,an appropriate ECN marking is selected based on the queue length and its growth slope,and the congestion window(CWND)is adjusted by calculating RTT.Simultaneously,the marking threshold for queue length is continuously adapted using the current queue length of the switch as a parameter to accommodate changes in data centers.The evaluation conducted through Mininet simulations demonstrates that DA-DCTCP yields advantages in terms of throughput,flow completion time(FCT),latency,and resistance against packet loss.These benefits contribute to reducing data center congestion,enhancing the stability of data transmission,and improving throughput.
基金This work is financially supported by the National Science Foundation of Tianjin(17JCYBJC23300).
文摘Phosphate removal is crucial for eutrophication control and water quality improvement.Electro-assisted adsorption,an eco-friendly elec-trosorption process,exhibited a promising potential for wastewater treatment.However,there are few works focused on phosphate electro-sorption,and reported electrodes cannot attach satisfactory removal capacities and rates.Herein,electro-assisted adsorption of phosphate via in-situ construction of La active centers on hierarchically porous carbon(LaPC)has been originally demonstrated.The resulted LaPC composite not only possessed a hierarchically porous structure with uniformly dispersed La active sites,but also provided good conductivity for interfacial electron transfer.The LaPC electrode achieved an ultrahigh phosphate electrosorption capability of 462.01 mg g^(-1) at 1 V,outperforming most existing electrodes.The superior phosphate removal performance originates from abundant active centers formed by the coupling of electricfield and capture sites.Besides,the stability and selectivity toward phosphate capture were maintained well even under comprehensive conditions.Moreover,a series of kinetics and isotherms models were employed to validate the electrosorption process.This work demonstrates a deep understanding and promotes a new level of phosphate electrosorption.
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFB2012600)the Science and Technology Plan Project of State Administration of Market Regulation,China(Grant No.2021MK039)。
文摘An integrated quantum probe for magnetic field imaging is proposed,where the nitrogen–vacancy(NV)center fixed at the fiber tip is located on the periphery of flexible ring resonator.Using flexible polyimide(PI)as the substrate medium,we design a circular microstrip antenna,which can achieve a bandwidth of 140 MHz at Zeeman splitting frequency of 2.87 GHz,specifically suitable for NV center experiments.Subsequently,this antenna is seamlessly fixed at a three-dimensional-printed cylindrical support,allowing the optical fiber tip to extend out of a dedicated aperture.To mitigate errors originating from processing,precise tuning within a narrow range can be achieved by adjusting the conformal amplitude.Finally,we image the microwave magnetic field around the integrated probe with high resolution,and determine the suitable area for placing the fiber tip(SAP).
