Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational...Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational techniques,and experience.This made providing meteorological services for this event particularly challenging.The China Meteorological Administration(CMA)Earth System Modeling and Prediction Centre,achieved breakthroughs in research on short-and medium-term deterministic and ensemble numerical predictions.Several key technologies crucial for precise winter weather services during the Winter Olympics were developed.A comprehensive framework,known as the Operational System for High-Precision Weather Forecasting for the Winter Olympics,was established.Some of these advancements represent the highest level of capabilities currently available in China.The meteorological service provided to the Beijing 2022 Games also exceeded previous Winter Olympic Games in both variety and quality.This included achievements such as the“100-meter level,minute level”downscaled spatiotemporal resolution and forecasts spanning 1 to 15 days.Around 30 new technologies and over 60 kinds of products that align with the requirements of the Winter Olympics Organizing Committee were developed,and many of these techniques have since been integrated into the CMA’s operational national forecasting systems.These accomplishments were facilitated by a dedicated weather forecasting and research initiative,in conjunction with the preexisting real-time operational forecasting systems of the CMA.This program represents one of the five subprograms of the WMO’s high-impact weather forecasting demonstration project(SMART2022),and continues to play an important role in their Regional Association(RA)II Research Development Project(Hangzhou RDP).Therefore,the research accomplishments and meteorological service experiences from this program will be carried forward into forthcoming highimpact weather forecasting activities.This article provides an overview and assessment of this program and the operational national forecasting systems.展开更多
The thermal transport properties of NiNB_(2)O_(6)as anode material for lithium-ion battery and the effect of strain were studied by machine learning interatomic potential combined with Boltzmann transport equation.The...The thermal transport properties of NiNB_(2)O_(6)as anode material for lithium-ion battery and the effect of strain were studied by machine learning interatomic potential combined with Boltzmann transport equation.The results show that the lattice thermal conductivity of NiNB_(2)O_(6)along the three crystal directions[100],[010],and[001]are 0.947 W·m^(-1)·K^(-1),0.727 W·m^(-1)·K^(-1),and 0.465 W·m^(-1)·K^(-1),respectively,indicating the anisotropy of the lattice thermal conductivity of NiNB_(2)O_(6).This anisotropy of the lattice thermal conductivity stems from the significant difference of phonon group velocities in different crystal directions of NiNB_(2)O_(6).When the tensile strain is applied along the[001]crystal direction,the lattice thermal conductivity in all three directions decreases.However,when the compressive strain is applied,the lattice thermal conductivity in the[100]and[010]crystal directions is increased,while the lattice thermal conductivity in the[001]crystal direction is abnormally reduced due to the significant inhibition of compressive strain on the group velocity.These indicate that the anisotropy of thermal conductivity of NiNB_(2)O_(6)can be enhanced by the compressive strain,and reduced by the tensile strain.展开更多
Objective:To study the effects of Dexmedetomidine combined with Sufentanil on hemodynamics, stress state, helper T cytokines and pain degree during the waking period of general anesthesia in elderly patients with lowe...Objective:To study the effects of Dexmedetomidine combined with Sufentanil on hemodynamics, stress state, helper T cytokines and pain degree during the waking period of general anesthesia in elderly patients with lower limb fracture surgery were studied.Methods:From June 2017 to July 2018, 95 elderly patients with lower limb fracture who visited First Affiliated Hospital of Xi 'an Jiaotong University and received fracture surgery and general anesthesia were collected. According to their different anesthesia methods, 46 patients were divided into the sufentanil maintenance anesthesia group (Sufentanil group), and 49 patients were divided into the metopidine combined with sufentanil maintenance anesthesia group (Joint group). Changes in hemodynamics (HR, SpO2, MAP) of the two groups were monitored at different times throughout the operation. Using enzyme-linked immunoassay detection of two groups of patients in maintain anesthesia and anesthesia to stress index (Cor, E, FIns and HOMA-IR). The the changes of pain mediators (NO,β-EP, SP) and helper T cytokines (IFN-γ, TNF-α) were compared between the two groups before and 24 hours after surgery. Results:In the combined group, HR, SpO2, MAP and sufentanil groups showed little change in SpO2 during anesthesia, with no significant difference. The HR and MAP of T2 and T3 in the sufentanil group were significantly higher than those in the combined group at T2 and T3. The stress indicators Cor, E, FIns and HOMA-IR in the anesthesia of the two groups were significantly higher than those in the anesthesia maintenance. The serum stress indexes of Cor, E, FIns and HOMA-IR were significantly lower in the combined group than in the sufentanil group. The IFN-γ level of the combined group was significantly higher than that of the sufentanil group, and the TNF-α level was significantly lower than that of the control group. Serum levels of NO,β-EP and SP were significantly higher in the two groups 24 h after surgery. Serum pain mediators NO,β-EP and SP in the combined group were significantly lower than those in the sufentanil group before and 24 h after surgery.Conclusion: Combined anesthesia with Remifentanil and Propofol can stabilize the hemodynamic state of patients undergoing craniotomy, reduce cardiovascular stress response and inflammatory response, reduce nerve damage, and play a role in brain protection.展开更多
In marginally jammed solids confined by walls,we calculate the particle and ensemble averaged value of an order parameter,Ψ(r),as a function of the distance to the wall,r.Being a microscopic indicator of structural d...In marginally jammed solids confined by walls,we calculate the particle and ensemble averaged value of an order parameter,Ψ(r),as a function of the distance to the wall,r.Being a microscopic indicator of structural disorder and particle mobility in solids,Ψis by definition the response of the mean square particle displacement to the increase of temperature in the harmonic approximation and can be directly calculated from the normal modes of vibration of the zerotemperature solids.We find that,in confined jammed solids,Ψ(r)curves at different pressures can collapse onto the same master curve following a scaling function,indicating the criticality of the jamming transition.The scaling collapse suggests a diverging length scale and marginal instability at the jamming transition,which should be accessible to sophisticatedly designed experiments.Moreover,Ψ(r)is found to be significantly suppressed when approaching the wall and anisotropic in directions perpendicular and parallel to the wall.This finding can be applied to understand the r-dependence and anisotropy of the structural relaxation in confined supercooled liquids,providing another example of understanding or predicting behaviors of supercooled liquids from the perspective of the zero-temperature amorphous solids.展开更多
We experimentally probe the coupling between particle shape and long-range interaction,using long-range interacting polygons.For two typical space-filling polygons,square and triangle,we find two types of coupling mod...We experimentally probe the coupling between particle shape and long-range interaction,using long-range interacting polygons.For two typical space-filling polygons,square and triangle,we find two types of coupling modes that predominantly control the structure formation.Specifically,the rotational ordering of squares brings a lattice deformation that produces a hexagonal-to-rhombic transition in the high density regime,whereas the alignment of triangles introduces a large geometric frustration that causes an order-to-disorder transition.Moreover,the two coupling modes lead to small and large“internal roughness”of the two systems,and thus predominantly control their structure relaxations.Our study thus provides a physical picture to the coupling between long-range interaction effect and short-range shape effect in the high-density regime unexplored before.展开更多
One potential solution to the problems of energy storage and conversion is the use of reversible protonic ceramic electrochemical cells(R-PCEC),which are based on the solid oxide fuel cell(SOFC)technology and offer a ...One potential solution to the problems of energy storage and conversion is the use of reversible protonic ceramic electrochemical cells(R-PCEC),which are based on the solid oxide fuel cell(SOFC)technology and offer a flexible route to the generation of renewable fuels.However,the R-PCEC development faces a range of significant challenges,including slow oxygen reaction kinetics,inadequate durability,and poor round-trip efficiency resulting from the inadequacy of an air electrode.To address these issues,we report novel B-sites doped Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.3)O_(3−δ)(PBCF)with varying amounts of Sn as the air electrode for R-PCEC to further enhance electrochemical performance at lower temperatures.At 600℃,R-PCEC with an air electrode consisting of Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.25)Sn_(0.05)O_(3+δ)has achieved peak power density of 1.12 W∙cm^(−2) in the fuel cell mode and current density of 1.79 A∙cm^(−2) in the electrolysis mode at a voltage of 1.3 V.Moreover,R-PCECs have shown good stability in the electrolysis mode of 100 h.This study presents a practical method for developing durable high-performance air electrodes for R-PCECs.展开更多
Solid oxide fuel cells(SOFCs)are widely recognized as efficient energy sources that have the potential to shape the future of energy development.Among various types of SOFCs,the low-temperature operation of protoncond...Solid oxide fuel cells(SOFCs)are widely recognized as efficient energy sources that have the potential to shape the future of energy development.Among various types of SOFCs,the low-temperature operation of protonconducting SOFCs(H–SOFCs)offers distinct advantages for wide commercialization compared to oxygen-ion conducting SOFCs(O–SOFCs).However,the commercialization of H–SOFCs is hindered by several challenges,including slow oxygen reduction kinetics and long-term instability of cathode materials.The electrochemical performance of the cathode system in H–SOFCs is limited by the poor proton conductivity of the cathode material and the scarcity of surface reaction sites.Additionally,the presence of undesirable phases induced by elements such as Cr and CO_(2)adversely affects the chemical stability and catalytic activity of the cathode.Thermal stress arising from the mismatch in coefficient of thermal expansion between the cathode and electrolyte further adds to the challenges.Therefore,this comprehensive review presents underlying mechanisms and potential solutions to overcome the challenges in H–SOFCs,leading to higher efficiency and wider commercialization of H–SOFCs.展开更多
A wideband wavelength-tunable 4×5 distributed feedback(DFB)semiconductor laser array based on the reconstructionequivalent-chirp(REC)technique using a simple tuning scheme is demonstrated.It consists of 20 DFB la...A wideband wavelength-tunable 4×5 distributed feedback(DFB)semiconductor laser array based on the reconstructionequivalent-chirp(REC)technique using a simple tuning scheme is demonstrated.It consists of 20 DFB lasers with 4×5matrix interleaving distributions,two-level cascaded Y-branch optical combiners,and one active semiconductor opticalamplifier(SOA),all in-series integrated on one chip.Unlike the traditional thermal-electric cooler(TEC)-based wavelength-tuning scheme,the tunable 4×5 REC-DFB laser array achieves a faster and broader continuous wavelength-tuningrange using TaN thin-film heaters integrated on the AlN submount.By changing the injection current of the TaN resistorfrom 0 to 190 mA,the proposed tunable laser achieves a wavelength-tuning range of∼2.5 nm per channel and a total tuningof over 50 nm.This study opens up new avenues for realizing cost-effective and wide-tuning-range semiconductor lasers.展开更多
The integration of a display function with wearable interactive sensors offers a promising way to synchronously detect physiological signals and visualize pressure/stimuli.However,combining these two functions in a st...The integration of a display function with wearable interactive sensors offers a promising way to synchronously detect physiological signals and visualize pressure/stimuli.However,combining these two functions in a strain sensor textile is a longstanding challenge due to the physical separation of sensors and display units.Here,a water-stable luminescent perovskite hydrogel(emission band approximately 25 nm)is constructed by blending as-prepared CsPbBr_(3)@PbBr(OH)with stretchable polyacrylamide(PAM)hydrogels.The facile introduction of CsPbBr_(3)@PbBr(OH)endows the hydrogels with excellent optical properties and a high mechanical strength of 51.3 kPa at a fracture strain of 740%.Interestingly,the resulting hydrogels retain bright green fluorescence under conditions including water,ultraviolet light,and extensive stretching(>700%).As a proof-of-concept,a novel wearable stretchable strain sensor textile based on these hydrogels is developed,and it displays visual-digital synergetic strain detection ability.It can perceive various motions on the human body in real time with electronic output signals from changes in resistance and simultaneously readable optical output signals,whether on land or underwater.This work provides a meaningful guide to rationally design perovskite hydrogels and accelerates the development of wearable visual-digital strain sensor textiles.展开更多
By introducing four fundamental types of disorders into a two-dimensional triangular lattice separately, we determine the role of each type of disorder in the vibration of the resulting mass-spring networks. We are co...By introducing four fundamental types of disorders into a two-dimensional triangular lattice separately, we determine the role of each type of disorder in the vibration of the resulting mass-spring networks. We are concerned mainly with the origin of the boson peak and the connection between the boson peak and the transverse Ioffe-Regel limit. For all types of disorders, we observe the emergence of the boson peak and Ioffe-Regel limits. With increasing disorder, the boson peak frequency ωBP, transverse Ioffe-Regel frequency ω^TIR, and longitudinal Ioffe-Regel frequency wLn all decrease. We find that there are two ways for the boson peak to form： developing from and coexisting with （but remaining independent of） the transverse van Hove singularity without and with local coordination number fluctuation. In the presence of a single type of disorder, ωTR 〉 wBp, and ωTIR≈BP only when the disorder is sufficiently strong and causes spatial fluctuation of the local coordination number. Moreover, if there is no positional disorder, ωTIR ≈ωLIR. Therefore, the argument that the boson peak is equivalent to the transverse Ioffe-Regel limit is not general. Our results suggest that both local coordination number and positional disorder are necessary for the argument to hold, which is actually the case for most disordered solids such as marginally jammed solids and structural glasses. We further combine two types of disorders to cause disorder in both the local coordination number and lattice site position. The density of vibrational states of the resulting networks resembles that of marginally jammed solids well. However, the relation between the boson peak and the transverse Ioffe-Regel limit is still indefinite and condition-dependent. Therefore, the interplay between different types of disorders is complicated, and more in-depth studies are required to sort it out.展开更多
Proteins synthesized in the endoplasmic reticulum （ER） are properly folded with the assistance of ER chaperones. Accumulation of misfolded protein in the ER triggers an adaptive ER stress （ERS） response termed the...Proteins synthesized in the endoplasmic reticulum （ER） are properly folded with the assistance of ER chaperones. Accumulation of misfolded protein in the ER triggers an adaptive ER stress （ERS） response termed the unfolded protein response. Recent interest has focused on the possibility that the accumulation of misfolded proteins can also contribute to reproductive response, including preimplantation embryos, testicular germ cell, placenta, and unexplained intrauterine growth restriction （IUGR）. The major ERS pathway constituents are present at all stages of preimplantation development and that the activation of ERS pathways can be induced at the 8-cell, morula and blastocyst stage. This review mainly introduced the research progress of ERS induced apoptosis of reproductive cells, providing a new direction for the research of reproductive disease therapy.展开更多
Horizontal wells show better affect and higher success rate in low water ratio cement,complex fracture zone,crevice and heavy oil blocks,it is the main measures to expand control area of a single well.Hydraulic fractu...Horizontal wells show better affect and higher success rate in low water ratio cement,complex fracture zone,crevice and heavy oil blocks,it is the main measures to expand control area of a single well.Hydraulic fracturing technology is the most financial way to improve the penetration of the reservoir to increase the production.However,compare with the vertical wells,the fracture of Horizontal wells are more complex,and lead to the initiation crack pressure is much higher than vertical wells.In this paper,defined the crack judging basis,and established the finite element model which could compute the initial crack pressure,to research the affection mechanism of perforation azimuth angle,density,diameter and depth,to provide references of perforation project's design and optimize.The research of this paper has significances on further understanding the affection mechanism of perforation parameters.展开更多
Circulating tumor DNA(ctDNA)is a DNA fragment released into the peripheral blood by apoptotic or necrotic tumor cells,which carry the basic genetic information after gene mutation.The detection and analysis of ctDNA c...Circulating tumor DNA(ctDNA)is a DNA fragment released into the peripheral blood by apoptotic or necrotic tumor cells,which carry the basic genetic information after gene mutation.The detection and analysis of ctDNA can provide genomic information on the size and development of tumor;therefore,it is considered as an emerging and promising tumor biomarker for cancer progression,reoccurrence,and routine monitoring after surgery.Albeit the isolation method is relatively simple due to the stability of ctDNA,the abundance of ctDNA is extremely low,and result from the high content of background cell free DNA(cfDNA),the large difference between individuals,and the need of predicted detection sites,it is necessary to analyze ctDNA in a comprehensive way.At present,the main methods that meet the needs of ctDNA detection with sensitivity and specificity are amplification refractory mutation system PCR(ARMS-PCR),digital-PCR(dPCR)and high-throughput sequencing.Among them,dPCR has advantages in practicality,which can realize absolute quantification of single-molecule DNA,detect and trace DNA molecules and conduct quantitative analysis,providing a reliable basis for clinical monitoring of tumor recurrence and minimal residual diseases.The study reviews the detection and potential value of ctDNA in gynecologic tumors.展开更多
基金This work was jointly supported by the National Natural Science Foundation of China(Grant Nos.41975137,42175012,and 41475097)the National Key Research and Development Program(Grant No.2018YFF0300103).
文摘Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational techniques,and experience.This made providing meteorological services for this event particularly challenging.The China Meteorological Administration(CMA)Earth System Modeling and Prediction Centre,achieved breakthroughs in research on short-and medium-term deterministic and ensemble numerical predictions.Several key technologies crucial for precise winter weather services during the Winter Olympics were developed.A comprehensive framework,known as the Operational System for High-Precision Weather Forecasting for the Winter Olympics,was established.Some of these advancements represent the highest level of capabilities currently available in China.The meteorological service provided to the Beijing 2022 Games also exceeded previous Winter Olympic Games in both variety and quality.This included achievements such as the“100-meter level,minute level”downscaled spatiotemporal resolution and forecasts spanning 1 to 15 days.Around 30 new technologies and over 60 kinds of products that align with the requirements of the Winter Olympics Organizing Committee were developed,and many of these techniques have since been integrated into the CMA’s operational national forecasting systems.These accomplishments were facilitated by a dedicated weather forecasting and research initiative,in conjunction with the preexisting real-time operational forecasting systems of the CMA.This program represents one of the five subprograms of the WMO’s high-impact weather forecasting demonstration project(SMART2022),and continues to play an important role in their Regional Association(RA)II Research Development Project(Hangzhou RDP).Therefore,the research accomplishments and meteorological service experiences from this program will be carried forward into forthcoming highimpact weather forecasting activities.This article provides an overview and assessment of this program and the operational national forecasting systems.
基金the National Natural Science Foundation of China(Grant Nos.12074115 and 11874145)the Natural Science Foundation of Hunan Province,China(Grant No.2021JJ30202)。
文摘The thermal transport properties of NiNB_(2)O_(6)as anode material for lithium-ion battery and the effect of strain were studied by machine learning interatomic potential combined with Boltzmann transport equation.The results show that the lattice thermal conductivity of NiNB_(2)O_(6)along the three crystal directions[100],[010],and[001]are 0.947 W·m^(-1)·K^(-1),0.727 W·m^(-1)·K^(-1),and 0.465 W·m^(-1)·K^(-1),respectively,indicating the anisotropy of the lattice thermal conductivity of NiNB_(2)O_(6).This anisotropy of the lattice thermal conductivity stems from the significant difference of phonon group velocities in different crystal directions of NiNB_(2)O_(6).When the tensile strain is applied along the[001]crystal direction,the lattice thermal conductivity in all three directions decreases.However,when the compressive strain is applied,the lattice thermal conductivity in the[100]and[010]crystal directions is increased,while the lattice thermal conductivity in the[001]crystal direction is abnormally reduced due to the significant inhibition of compressive strain on the group velocity.These indicate that the anisotropy of thermal conductivity of NiNB_(2)O_(6)can be enhanced by the compressive strain,and reduced by the tensile strain.
文摘Objective:To study the effects of Dexmedetomidine combined with Sufentanil on hemodynamics, stress state, helper T cytokines and pain degree during the waking period of general anesthesia in elderly patients with lower limb fracture surgery were studied.Methods:From June 2017 to July 2018, 95 elderly patients with lower limb fracture who visited First Affiliated Hospital of Xi 'an Jiaotong University and received fracture surgery and general anesthesia were collected. According to their different anesthesia methods, 46 patients were divided into the sufentanil maintenance anesthesia group (Sufentanil group), and 49 patients were divided into the metopidine combined with sufentanil maintenance anesthesia group (Joint group). Changes in hemodynamics (HR, SpO2, MAP) of the two groups were monitored at different times throughout the operation. Using enzyme-linked immunoassay detection of two groups of patients in maintain anesthesia and anesthesia to stress index (Cor, E, FIns and HOMA-IR). The the changes of pain mediators (NO,β-EP, SP) and helper T cytokines (IFN-γ, TNF-α) were compared between the two groups before and 24 hours after surgery. Results:In the combined group, HR, SpO2, MAP and sufentanil groups showed little change in SpO2 during anesthesia, with no significant difference. The HR and MAP of T2 and T3 in the sufentanil group were significantly higher than those in the combined group at T2 and T3. The stress indicators Cor, E, FIns and HOMA-IR in the anesthesia of the two groups were significantly higher than those in the anesthesia maintenance. The serum stress indexes of Cor, E, FIns and HOMA-IR were significantly lower in the combined group than in the sufentanil group. The IFN-γ level of the combined group was significantly higher than that of the sufentanil group, and the TNF-α level was significantly lower than that of the control group. Serum levels of NO,β-EP and SP were significantly higher in the two groups 24 h after surgery. Serum pain mediators NO,β-EP and SP in the combined group were significantly lower than those in the sufentanil group before and 24 h after surgery.Conclusion: Combined anesthesia with Remifentanil and Propofol can stabilize the hemodynamic state of patients undergoing craniotomy, reduce cardiovascular stress response and inflammatory response, reduce nerve damage, and play a role in brain protection.
基金Project supported by the National Natural Science Foundation of China(Grant No.11734014)。
文摘In marginally jammed solids confined by walls,we calculate the particle and ensemble averaged value of an order parameter,Ψ(r),as a function of the distance to the wall,r.Being a microscopic indicator of structural disorder and particle mobility in solids,Ψis by definition the response of the mean square particle displacement to the increase of temperature in the harmonic approximation and can be directly calculated from the normal modes of vibration of the zerotemperature solids.We find that,in confined jammed solids,Ψ(r)curves at different pressures can collapse onto the same master curve following a scaling function,indicating the criticality of the jamming transition.The scaling collapse suggests a diverging length scale and marginal instability at the jamming transition,which should be accessible to sophisticatedly designed experiments.Moreover,Ψ(r)is found to be significantly suppressed when approaching the wall and anisotropic in directions perpendicular and parallel to the wall.This finding can be applied to understand the r-dependence and anisotropy of the structural relaxation in confined supercooled liquids,providing another example of understanding or predicting behaviors of supercooled liquids from the perspective of the zero-temperature amorphous solids.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11774059 and 11734014).
文摘We experimentally probe the coupling between particle shape and long-range interaction,using long-range interacting polygons.For two typical space-filling polygons,square and triangle,we find two types of coupling modes that predominantly control the structure formation.Specifically,the rotational ordering of squares brings a lattice deformation that produces a hexagonal-to-rhombic transition in the high density regime,whereas the alignment of triangles introduces a large geometric frustration that causes an order-to-disorder transition.Moreover,the two coupling modes lead to small and large“internal roughness”of the two systems,and thus predominantly control their structure relaxations.Our study thus provides a physical picture to the coupling between long-range interaction effect and short-range shape effect in the high-density regime unexplored before.
基金supported by the National Natural Science Foundation of China(No.11875164)Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(No.18KJA430017)U.S.National Science Foundation(No.1832809).
文摘One potential solution to the problems of energy storage and conversion is the use of reversible protonic ceramic electrochemical cells(R-PCEC),which are based on the solid oxide fuel cell(SOFC)technology and offer a flexible route to the generation of renewable fuels.However,the R-PCEC development faces a range of significant challenges,including slow oxygen reaction kinetics,inadequate durability,and poor round-trip efficiency resulting from the inadequacy of an air electrode.To address these issues,we report novel B-sites doped Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.3)O_(3−δ)(PBCF)with varying amounts of Sn as the air electrode for R-PCEC to further enhance electrochemical performance at lower temperatures.At 600℃,R-PCEC with an air electrode consisting of Pr_(0.5)Ba_(0.5)Co_(0.7)Fe_(0.25)Sn_(0.05)O_(3+δ)has achieved peak power density of 1.12 W∙cm^(−2) in the fuel cell mode and current density of 1.79 A∙cm^(−2) in the electrolysis mode at a voltage of 1.3 V.Moreover,R-PCECs have shown good stability in the electrolysis mode of 100 h.This study presents a practical method for developing durable high-performance air electrodes for R-PCECs.
基金supported by the National Natural Science Foundation of China(Grant Nos.:11875164)National Undergraduate Training Program for Innovation and Entrepreneurship(Grant No.S202110555264)Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(No.18KJA430017).
文摘Solid oxide fuel cells(SOFCs)are widely recognized as efficient energy sources that have the potential to shape the future of energy development.Among various types of SOFCs,the low-temperature operation of protonconducting SOFCs(H–SOFCs)offers distinct advantages for wide commercialization compared to oxygen-ion conducting SOFCs(O–SOFCs).However,the commercialization of H–SOFCs is hindered by several challenges,including slow oxygen reduction kinetics and long-term instability of cathode materials.The electrochemical performance of the cathode system in H–SOFCs is limited by the poor proton conductivity of the cathode material and the scarcity of surface reaction sites.Additionally,the presence of undesirable phases induced by elements such as Cr and CO_(2)adversely affects the chemical stability and catalytic activity of the cathode.Thermal stress arising from the mismatch in coefficient of thermal expansion between the cathode and electrolyte further adds to the challenges.Therefore,this comprehensive review presents underlying mechanisms and potential solutions to overcome the challenges in H–SOFCs,leading to higher efficiency and wider commercialization of H–SOFCs.
基金supported by the Chinese National Key Basic Research Special Fund(Nos.2017YFA0206401,2018YFA0704402,2018YFB2201801,and 2018YFE0201200)National Key Research and Development Program of China(No.2020YFB2205800)+2 种基金National Natural Science Foundation of China(Nos.61975075,61975076,and 62004094)Natural Science Foundation of Jiangsu Province(No.BK20200334)Jiangsu Science and Technology Project(No.BE2017003-2).
文摘A wideband wavelength-tunable 4×5 distributed feedback(DFB)semiconductor laser array based on the reconstructionequivalent-chirp(REC)technique using a simple tuning scheme is demonstrated.It consists of 20 DFB lasers with 4×5matrix interleaving distributions,two-level cascaded Y-branch optical combiners,and one active semiconductor opticalamplifier(SOA),all in-series integrated on one chip.Unlike the traditional thermal-electric cooler(TEC)-based wavelength-tuning scheme,the tunable 4×5 REC-DFB laser array achieves a faster and broader continuous wavelength-tuningrange using TaN thin-film heaters integrated on the AlN submount.By changing the injection current of the TaN resistorfrom 0 to 190 mA,the proposed tunable laser achieves a wavelength-tuning range of∼2.5 nm per channel and a total tuningof over 50 nm.This study opens up new avenues for realizing cost-effective and wide-tuning-range semiconductor lasers.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20220288)Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(Start-up grant E1552102)+2 种基金This work was supported by the Singapore Ministry of Education Academic Research Fund Tier 2(MOE2019-T2-2-127 and MOE-T2EP50120-0002),and A*STAR under AME IRG(A2083c0062)This work was supported by A*STAR under its IAF-ICP Programme I2001E0067 and the Schaeffler Hub for Advanced Research at NTUThis work was also supported by NTU-PSL Joint Lab collaboration。
文摘The integration of a display function with wearable interactive sensors offers a promising way to synchronously detect physiological signals and visualize pressure/stimuli.However,combining these two functions in a strain sensor textile is a longstanding challenge due to the physical separation of sensors and display units.Here,a water-stable luminescent perovskite hydrogel(emission band approximately 25 nm)is constructed by blending as-prepared CsPbBr_(3)@PbBr(OH)with stretchable polyacrylamide(PAM)hydrogels.The facile introduction of CsPbBr_(3)@PbBr(OH)endows the hydrogels with excellent optical properties and a high mechanical strength of 51.3 kPa at a fracture strain of 740%.Interestingly,the resulting hydrogels retain bright green fluorescence under conditions including water,ultraviolet light,and extensive stretching(>700%).As a proof-of-concept,a novel wearable stretchable strain sensor textile based on these hydrogels is developed,and it displays visual-digital synergetic strain detection ability.It can perceive various motions on the human body in real time with electronic output signals from changes in resistance and simultaneously readable optical output signals,whether on land or underwater.This work provides a meaningful guide to rationally design perovskite hydrogels and accelerates the development of wearable visual-digital strain sensor textiles.
文摘By introducing four fundamental types of disorders into a two-dimensional triangular lattice separately, we determine the role of each type of disorder in the vibration of the resulting mass-spring networks. We are concerned mainly with the origin of the boson peak and the connection between the boson peak and the transverse Ioffe-Regel limit. For all types of disorders, we observe the emergence of the boson peak and Ioffe-Regel limits. With increasing disorder, the boson peak frequency ωBP, transverse Ioffe-Regel frequency ω^TIR, and longitudinal Ioffe-Regel frequency wLn all decrease. We find that there are two ways for the boson peak to form： developing from and coexisting with （but remaining independent of） the transverse van Hove singularity without and with local coordination number fluctuation. In the presence of a single type of disorder, ωTR 〉 wBp, and ωTIR≈BP only when the disorder is sufficiently strong and causes spatial fluctuation of the local coordination number. Moreover, if there is no positional disorder, ωTIR ≈ωLIR. Therefore, the argument that the boson peak is equivalent to the transverse Ioffe-Regel limit is not general. Our results suggest that both local coordination number and positional disorder are necessary for the argument to hold, which is actually the case for most disordered solids such as marginally jammed solids and structural glasses. We further combine two types of disorders to cause disorder in both the local coordination number and lattice site position. The density of vibrational states of the resulting networks resembles that of marginally jammed solids well. However, the relation between the boson peak and the transverse Ioffe-Regel limit is still indefinite and condition-dependent. Therefore, the interplay between different types of disorders is complicated, and more in-depth studies are required to sort it out.
文摘Proteins synthesized in the endoplasmic reticulum （ER） are properly folded with the assistance of ER chaperones. Accumulation of misfolded protein in the ER triggers an adaptive ER stress （ERS） response termed the unfolded protein response. Recent interest has focused on the possibility that the accumulation of misfolded proteins can also contribute to reproductive response, including preimplantation embryos, testicular germ cell, placenta, and unexplained intrauterine growth restriction （IUGR）. The major ERS pathway constituents are present at all stages of preimplantation development and that the activation of ERS pathways can be induced at the 8-cell, morula and blastocyst stage. This review mainly introduced the research progress of ERS induced apoptosis of reproductive cells, providing a new direction for the research of reproductive disease therapy.
基金This research is supported by the Natural Science Fund for Outstanding Youth Science Fund(Grant No.51222406)New Century Excellent Talents in University of China(NCET-12-1061)+2 种基金Scientific Research Innovation Team Project of Sichuan Colleges and Universities(12TD007)the key projects of academic and technical leaders cultivate fund in Sichuan Province,China(2011-441-zxh)Sichuan Science and Technology Innovation Talent Project(20132057).
文摘Horizontal wells show better affect and higher success rate in low water ratio cement,complex fracture zone,crevice and heavy oil blocks,it is the main measures to expand control area of a single well.Hydraulic fracturing technology is the most financial way to improve the penetration of the reservoir to increase the production.However,compare with the vertical wells,the fracture of Horizontal wells are more complex,and lead to the initiation crack pressure is much higher than vertical wells.In this paper,defined the crack judging basis,and established the finite element model which could compute the initial crack pressure,to research the affection mechanism of perforation azimuth angle,density,diameter and depth,to provide references of perforation project's design and optimize.The research of this paper has significances on further understanding the affection mechanism of perforation parameters.
文摘Circulating tumor DNA(ctDNA)is a DNA fragment released into the peripheral blood by apoptotic or necrotic tumor cells,which carry the basic genetic information after gene mutation.The detection and analysis of ctDNA can provide genomic information on the size and development of tumor;therefore,it is considered as an emerging and promising tumor biomarker for cancer progression,reoccurrence,and routine monitoring after surgery.Albeit the isolation method is relatively simple due to the stability of ctDNA,the abundance of ctDNA is extremely low,and result from the high content of background cell free DNA(cfDNA),the large difference between individuals,and the need of predicted detection sites,it is necessary to analyze ctDNA in a comprehensive way.At present,the main methods that meet the needs of ctDNA detection with sensitivity and specificity are amplification refractory mutation system PCR(ARMS-PCR),digital-PCR(dPCR)and high-throughput sequencing.Among them,dPCR has advantages in practicality,which can realize absolute quantification of single-molecule DNA,detect and trace DNA molecules and conduct quantitative analysis,providing a reliable basis for clinical monitoring of tumor recurrence and minimal residual diseases.The study reviews the detection and potential value of ctDNA in gynecologic tumors.
