NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy leve...NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy levels and possible redox reactions at the NiO_(x)/perovskite interface severely limit the performance of NiO_(x) based inverted perovskite solar cells.Herein,we introduce a p-type self-assembled monolayer between NiO_(x)and perovskite layers to modify the interface and block the undesirable redox reaction between perovskite and NiO_(x)The selfassembled monolayer molecules all contain phosphoric acid function groups,which can be anchored onto the NiOr surface and passivate the surface defect.Moreover,the introduction of self-assembled monolayers can regulate the energy level structure of NiO_(x),reduce the interfacial band energy offset,and hence promote the hole transport from perovskite to NiO_(x)layer.Consequently,the device performance is significantly enhanced in terms of both power conversion efficiency and stability.展开更多
Spiking neural networks(SNNs)utilize brain-like spatiotemporal spike encoding for simulating brain functions.Photonic SNN offers an ultrahigh speed and power efficiency platform for implementing high-performance neuro...Spiking neural networks(SNNs)utilize brain-like spatiotemporal spike encoding for simulating brain functions.Photonic SNN offers an ultrahigh speed and power efficiency platform for implementing high-performance neuromorphic computing.Here,we proposed a multi-synaptic photonic SNN,combining the modified remote supervised learning with delayweight co-training to achieve pattern classification.The impact of multi-synaptic connections and the robustness of the network were investigated through numerical simulations.In addition,the collaborative computing of algorithm and hardware was demonstrated based on a fabricated integrated distributed feedback laser with a saturable absorber(DFB-SA),where 10 different noisy digital patterns were successfully classified.A functional photonic SNN that far exceeds the scale limit of hardware integration was achieved based on time-division multiplexing,demonstrating the capability of hardware-algorithm co-computation.展开更多
The phase precipitation behavior and tensile properties of an as-cast Ni-based alloy,IN617B alloy,after solution heat treatment and long-term aging treatment were investigated.Ti(C,N),M6C and M23C6 are the primary pre...The phase precipitation behavior and tensile properties of an as-cast Ni-based alloy,IN617B alloy,after solution heat treatment and long-term aging treatment were investigated.Ti(C,N),M6C and M23C6 are the primary precipitates in as-cast microstructure.After solution heat treatment,most of carbides dissolve into the matrix except a few fine Ti(C,N)within grains.During long-term aging at 700°C,the phase precipitation behaviors of the alloy are characterized as follows:(1)M23C6 carbides at grain boundaries(GBs)transform from film-like shape to cellular shape and gradually coarsen due to the decrease of the surface energy and element aggregation to GBs;(2)M23C6 carbides within grains have a bar-like morphology with a preferential growth direction[110]and have a cube-on-cube coherent orientation relationship with the matrixγ;(3)γ?particles inhibit the coarsening of M23C6 within grains by constraining the diffusion of formation elements.Furthermore,the tensile strength of the alloy obviously increases,but the ductility significantly decreases after the aging for 5000 h.The alloy has a relatively stable microstructure which guarantees the excellent tensile properties during long-term aging.展开更多
IN617B nickel-base superalloy is considered as a good candidate material in 700℃advanced ultrasupercritical coal-fired power plants.The effect of Ta addition on solidification microstructure and element segregation o...IN617B nickel-base superalloy is considered as a good candidate material in 700℃advanced ultrasupercritical coal-fired power plants.The effect of Ta addition on solidification microstructure and element segregation of IN617B alloy was investigated by OM,SEM,TEM,EDS,EPMA and thermodynamic calculation.The results showed that the solidification microstructure exhibited a dendritic segregation pattern with many primary carbides distributed in interdendritic regions,such as network M_(6)C,lath M_(23)C_(6) and granular Ti(C,N).The addition of Ta promoted the precipitation of Ta-rich MC significantly inhibiting the precipitation of M_(6)C and M_(23)C_(6),and reduced the segregation degree of Al,Mo and Ti alloying elements.The addition of Ta decreased the melting temperature of MC carbide,but did not impact the solidification path,that was,L→γmatrix→MC or Ti(C,N)→M_(6)C→M_(23)C_(6),where MC and Ti(C,N)tended to form symbiotic microstructure with M_(6)C.This study will provide theoretical basis and data support for the alloy optimization and casting structure control of IN617B nickel-based superalloy.展开更多
Two-dimensional(2D)metal carbides,MXene,present the promising application for the energy storage system.Among the MXene family,Ti_2CT_xas the lightest material,shows its unique electrochemical performance.Herein,Ti_2C...Two-dimensional(2D)metal carbides,MXene,present the promising application for the energy storage system.Among the MXene family,Ti_2CT_xas the lightest material,shows its unique electrochemical performance.Herein,Ti_2CT_xis synthesized by selective etching Al layer from the Ti_2Al C.With the optimized HF treating condition,Ti_2CT_xdisplays high volumetric capacitance and remarkable rate ability.Moreover,the Ti_2CT_x//Ti_2CT_xsymmetric supercapacitor is designed and assembled,which presents capable capacitance,outstanding rate performance and excellent cycling performance.The remarkable electrochemical performance is attributed to its 2D structure and high electronic conductivity.This work demonstrates the potential application of the Ti_2CT_xfor the supercapacitors and provides a template to design highperformance supercapacitors with 2D electrode materials.展开更多
Laser shock peening(LSP)is an attractive post-processing method to tailor surface microstructure and enhance mechanical performances of additive manufactured(AM)components.The effects of multiple LSP treatments on the...Laser shock peening(LSP)is an attractive post-processing method to tailor surface microstructure and enhance mechanical performances of additive manufactured(AM)components.The effects of multiple LSP treatments on the microstructure and mechanical properties of Ti-6Al-4V part produced by electron beam melting(EBM),as a mature AM process,were studied in this work.Microstructure,surface topography,residual stress,and tensile performance of EBM-manufactured Ti-6Al-4V specimens were systematically analyzed subjected to different LSP treatments.The distribution of porosities in EBM sample was assessed via X-ray computed tomography.The results showed that EBM samples with two LSP treatments possessed a lower porosity value of 0.05%compared to the value of 0.08%for the untreated samples.The strength of EBM samples with two LSP treatments was remarkably raised by 12%as compared with the as-built samples.The grains ofαphase were refined in near-surface layer,and a dramatic increase in the depth and magnitude of compressive residual stress(CRS)was achieved in EBM sample with multiple LSP treatments.The grain refinement ofαphase and CRS with larger depth were responsible for the strength enhancement of EBM samples with two LSP treatments.展开更多
Metal(Al,Ti,Zr)triflate grafted mesoporous SBA‐15(AlTf/S,TiTf/S,ZrTf/S)samples were synthesizedas inexpensive solid acid materials by a simple one‐pot‐two‐step synthesis methodology.These materials were characteri...Metal(Al,Ti,Zr)triflate grafted mesoporous SBA‐15(AlTf/S,TiTf/S,ZrTf/S)samples were synthesizedas inexpensive solid acid materials by a simple one‐pot‐two‐step synthesis methodology.These materials were characterized by X‐ray diffraction,N2‐sorption,thermogravimetric analysis,Fourier transform infrared spectroscopy(FT‐IR),in‐situ pyridine FT‐IR spectroscopy,and elementalanalysis.ZrTf/S was found to be a highly efficient and reusable solid acid catalyst for ring opening ofepoxides with amines and alcohols and producedβ‐amino alcohols andβ‐alkoxy alcohols respectivelyunder ambient reaction conditions.The ZrTf/S catalyst showed the highest activity,whichwas attributed to its high acidity compared with that of the Ti and Al containing samples.展开更多
The low immunogenicity of tumors remains one of the major limitations of cancer immunotherapy.Herein,we report a bacterial metabolisminitiated and photothermal-enhanced nanocatalytic therapy strategy to completely era...The low immunogenicity of tumors remains one of the major limitations of cancer immunotherapy.Herein,we report a bacterial metabolisminitiated and photothermal-enhanced nanocatalytic therapy strategy to completely eradicate primary tumor by triggering highly effective antitumor immune responses.Briefly,a microbiotic nanomedicine,designated as Cu_(2)O@ΔSt,has been constructed by conjugating PEGylated Cu_(2)O nanoparticles on the surface of an engineered Salmonella typhimurium strain(ΔSt).Owing to the natural hypoxia tropism ofΔSt,Cu_(2)O@ΔSt could selectively colonize hypoxic solid tumors,thus minimizing the adverse effects of the bacteria on normal tis-sues.Upon bacterial metabolism within the tumor,Cu_(2)O@ΔSt generates H_(2)S gas and other acidic substances in the tumor microenvironment(TME),which will in situ trigger the sulfidation of Cu_(2)O to form CuS facilitating tumor-specific photothermal therapy(PTT)under local NIR laser irradiation on the one hand.Meanwhile,the dissolved Cu+ions from Cu_(2)O into the acidified TME enables the nanocatalytic tumor therapy by catalyzing the Fenton-like reaction of decom-posing endogenous H_(2)O_(2) into cytotoxic hydroxyl radicals(·OH)on the other hand.Such a bacterial metabolism-triggered PTT-enhanced nanocatalytic treatment could effectively destroy tumor cells and induce a massive release of tumor antigens and damage-associated molecular patterns,thereby sensitizing tumors to checkpoint blockade(ICB)therapy.The combined nanocatalytic and ICB therapy results in the much-inhibited growth of distant and metastatic tumors,and more importantly,induces a powerful immunological memory effect after the primary tumor ablation.展开更多
In this paper,we have developed a highly efficient method for the direct preparation of propylene carbonate from propylene and carbon dioxide（CO2） using quaternary ammonium heteropolyphosphatotungstate–quaternary a...In this paper,we have developed a highly efficient method for the direct preparation of propylene carbonate from propylene and carbon dioxide（CO2） using quaternary ammonium heteropolyphosphatotungstate–quaternary ammonium halide catalytic system with anhydrous hydrogen peroxide as an oxidant through one-pot two-step process.The effects of the amount of tetrabutylammonium bromide（TBAB）,the concentration of hydrogen peroxide and other reaction conditions were investigated.The catalyst system gave an optimum propylene oxide yield（91%） at75°C in oxidation step and the highest propylene carbonate yield（99%） at 140°C and 3.0 MPa in cycloaddition step.Based on the results,a reaction mechanism has been proposed.展开更多
Atorvastatin, a lipid-lowering medication, provides neuroprotective effects, although the precise mechanisms of action remain unclear. Our previous studies confirmed activated autophagy following spinal cord injury, w...Atorvastatin, a lipid-lowering medication, provides neuroprotective effects, although the precise mechanisms of action remain unclear. Our previous studies confirmed activated autophagy following spinal cord injury, which was conducive to recovery of neurological functions. We hypothesized that atorvastatin could also activate autophagy after spinal cord injury, and subsequently improve recovery of neurological functions. A rat model of spinal cord injury was established based on the Allen method. Atorvastatin（5 mg/kg） was intraperitoneally injected at 1 and 2 days after spinal cord injury. At 7 days post-injury, western blot assay, reverse transcription-polymerase chain reaction, and terminal deoxynucleotidyl transferase-mediated dU TP nick-end labeling（TUNEL） staining results showed increased Beclin-1 and light chain 3B gene and protein expressions in the spinal cord injury ＋ atorvastatin group. Additionally, caspase-9 and caspase-3 expression was decreased, and the number of TUNEL-positive cells was reduced. Compared with the spinal cord injury ＋ saline group, Basso, Beattie, and Bresnahan locomotor rating scale scores significantly increased in the spinal cord injury ＋ atorvastatin group at 14–42 days post-injury. These findings suggest that atorvastatin activated autophagy after spinal cord injury, inhibited apoptosis, and promoted recovery of neurological function.展开更多
Disrupted-in-Schizophrenia 1 is a susceptibility gene for schizophrenia and other psychiatric disorders. Developmental lead exposure can cause neurological disorders similar to hyperactivity disorder, dyslexia and sch...Disrupted-in-Schizophrenia 1 is a susceptibility gene for schizophrenia and other psychiatric disorders. Developmental lead exposure can cause neurological disorders similar to hyperactivity disorder, dyslexia and schizophrenia. In the present study, we examined the impact of developmental lead exposure, administered in vitro and in vivo, on hippocampal Disrupted-In- Schizophrenia 1 expression. Our results show that in cultured hippocampal neurons, in vitro exposure to 0.1-10 pM lead, inhibited neurite growth and increased Disrupted-In-Schizophrenia 1 mRNA and protein expression dose-dependently. In addition, blood lead levels in mice were increased with increasing mouse maternal lead （0.01-1 mM） exposure. Hippocampal neurons from these mice showed a concomitant increase in Disrupted-in-Schizophrenia 1 mRNA and protein expression. Overall our findings suggest that in vivo and in vitro lead exposure increases Disrupted-In-Schizophrenia 1 expression in hippocampal neurons dose-dependently, and consequently may influence synapse formation in newborn neurons.展开更多
BACKGROUND Hemifacial microsomia(HFM)is the second most common craniofacial congenital anomaly following cleft lip and palate.Because of the various phenotypic spectra and the severity of the deformity,a wide range of...BACKGROUND Hemifacial microsomia(HFM)is the second most common craniofacial congenital anomaly following cleft lip and palate.Because of the various phenotypic spectra and the severity of the deformity,a wide range of treatment approaches have been proposed.Recently,the surgery-first approach(SFA)was introduced to treat mild to moderate HFM,and it yielded a balanced facial appearance.The SFA not only promotes rapid improvement in facial aesthetics but also considerably reduces the overall treatment time.CASE SUMMARY A female patient,aged 25 years old,sought orthodontic treatment with the chief complaint of dental and facial asymmetry.After a comprehensive physical examination and imaging analysis were performed,the patient was diagnosed with mild HFM that was primarily attributed to unilateral abnormal development of the maxilla-mandibular.The SFA was carried out to correct the skeletal deformity.The palatal suture was used as the midline of the maxilla in the surgical plan to center the maxilla,and the chin was also properly positioned to obtain a relatively symmetrical facial appearance.Four weeks after the surgery,the patient was referred for postsurgical orthodontics to decompensate the dentition and stabilize the occlusion.After 20 mo of treatment,all orthodontic appliances were removed.The posttreatment photographs of the patient and her smile confirmed good aesthetic and occlusal results.CONCLUSION Mild HFM can be corrected by SFA,which not only promotes rapid improvement in facial aesthetics but also considerably reduces the overall treatment time.展开更多
Crude oil is the world＇s leading fuel, and its prices have a big impact on the global environment, economy as well as oil exploration and exploitation activities. Oil price forecasts are very useful to industries, go...Crude oil is the world＇s leading fuel, and its prices have a big impact on the global environment, economy as well as oil exploration and exploitation activities. Oil price forecasts are very useful to industries, governments and individuals. Although many methods have been developed for predicting oil prices, it remains one of the most challenging forecasting problems due to the high volatility of oil prices. In this paper, we propose a novel approach for crude oil price prediction based on a new machine learning paradigm called stream learning. The main advantage of our stream learning approach is that the pre- diction model can capture the changing pattern of oil prices since the model is continuously updated whenever new oil price data are available, with very small constant overhead. To evaluate the forecasting ability of our stream learning model, we compare it with three other popular oil price prediction models. The experiment results show that our stream learning model achieves the highest accuracy in terms of both mean squared prediction error and directional accuracy ratio over a variety of forecast time horizons.展开更多
The weather at the Xinglong Observing Station, where the Guo Shou Jing Telescope （GSJT） is located, is strongly affected by the monsoon climate in north- east China. The LAMOST survey strategy is constrained by thes...The weather at the Xinglong Observing Station, where the Guo Shou Jing Telescope （GSJT） is located, is strongly affected by the monsoon climate in north- east China. The LAMOST survey strategy is constrained by these weather patterns. We present statistics on observing hours from 2004 to 2007, and the sky brightness, seeing, and sky transparency from 1995 to 2011 at the site. We investigate effects of the site conditions on the survey plan. Operable hours each month show a strong cor- relation with season： on average there are eight operable hours per night available in December, but only one-two hours in July and August. The seeing and the sky trans- parency also vary with season. Although the seeing is worse in windy winters, and the atmospheric extinction is worse in the spring and summer, the site is adequate for the proposed scientific program of the LAMOST survey. With a Monte Carlo simulation using historical data on the site condition, we find that the available observation hours constrain the survey footprint from 22h to 16h in right ascension; the sky brightness allows LAMOST to obtain a limiting magnitude of V = 19.5 mag with S/N= 10.展开更多
We describe a general target selection algorithm that is applicable to any survey in which the number of available candidates is much larger than the number of objects to be observed. This routine aims to achieve a ba...We describe a general target selection algorithm that is applicable to any survey in which the number of available candidates is much larger than the number of objects to be observed. This routine aims to achieve a balance between a smoothly- varying, well-understood selection function and the desire to preferentially select cer- tain types of targets. Some target-selection examples are shown that illustrate differentpossibilities of emphasis functions. Although it is generally applicable, the algorithm was developed specifically for the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE） survey that will be carried out using the Chinese Guo Shou Jing Telescope. In particular, this algorithm was designed for the portion of LEGUE targeting the Galactic halo, in which we attempt to balance a variety of science goals that require stars at fainter magnitudes than can be completely sampled by LAMOST. This algorithm has been implemented for the halo portion of the LAMOST pilot sur- vey, which began in October 2011.展开更多
A convenient,expeditious,and high-efficiency protocol for the transformation of alcohols into esters using a Co-modified N-doped mesoporous carbon material（Co-N/m-C）as the catalyst is proposed.The catalyst was prepa...A convenient,expeditious,and high-efficiency protocol for the transformation of alcohols into esters using a Co-modified N-doped mesoporous carbon material（Co-N/m-C）as the catalyst is proposed.The catalyst was prepared through direct pyrolysis of a macromolecular precursor.The catalyst prepared using a pyrolysis temperature of 900°C（labeled Co-N/m-C-900） exhibited the best per-formance.The strong coordination between the ultra-dispersed cobalt species and the pyridine nitrogen as well as the large area of the mesoporous surface resulted in a high turnover frequencymethyl benzoate.This value is much higher than those of state-of-the-art transition-metal-based nanocatalysts reported in the literature.Moreover,the catalyst exhibited general applicability to various structurally diverse alcohols,including benzylic,allylic,and heterocyclic alcohols,achieving the target esters in high yields.In addition,a preliminary evaluation revealed that Co-N/m-C-900 can be used six times without significant activity loss.In general,the process was rapid,simple,and cost-effective.展开更多
A simple, rapid and sensitive method based on an ultra-performance liquid chromatography tandem mass spectrometry （UPLC-MS/MS） has been developed and validated for the determination of pimavanserin in rat plasma. Th...A simple, rapid and sensitive method based on an ultra-performance liquid chromatography tandem mass spectrometry （UPLC-MS/MS） has been developed and validated for the determination of pimavanserin in rat plasma. The analyte was extracted by protein precipitation with methanol and separated on an ACQUITY BEH C18 column （100 mm × 2.1 mm, 1.7μm; Waters, USA）, with an isocratic elution of acetonitrile-water containing 10 mM ammonium acetate （70：30, v/v）, at a flow rate of 0.2 mL/min for 2.5 rain. The analyte and clarithromyein （the internal standard） were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 428.2 - 223.0 for pimavanserin and m/z 748.5 - 589.5 for clarithromycin. Relative coefficient （r） for the calibration curve was more than 0.9980. The intra-day and inter-day precisions （relative standard deviation, RSD%） were less than 13.3% and 10.5%, respectively, and the accuracy （relative error, RE%） was within ± 11.5%. The analytical method was successfully applied to a routine pharmacokinetic study of pimavanserin in rats after oral administration at the dose of 10 mg/kg.展开更多
文摘NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy levels and possible redox reactions at the NiO_(x)/perovskite interface severely limit the performance of NiO_(x) based inverted perovskite solar cells.Herein,we introduce a p-type self-assembled monolayer between NiO_(x)and perovskite layers to modify the interface and block the undesirable redox reaction between perovskite and NiO_(x)The selfassembled monolayer molecules all contain phosphoric acid function groups,which can be anchored onto the NiOr surface and passivate the surface defect.Moreover,the introduction of self-assembled monolayers can regulate the energy level structure of NiO_(x),reduce the interfacial band energy offset,and hence promote the hole transport from perovskite to NiO_(x)layer.Consequently,the device performance is significantly enhanced in terms of both power conversion efficiency and stability.
基金supports from the National Key Research and Development Program of China (Nos.2021YFB2801900,2021YFB2801901,2021YFB2801902,2021YFB2801903,2021YFB2801904)the National Outstanding Youth Science Fund Project of National Natural Science Foundation of China (No.62022062)+1 种基金the National Natural Science Foundation of China (No.61974177)the Fundamental Research Funds for the Central Universities (No.QTZX23041).
文摘Spiking neural networks(SNNs)utilize brain-like spatiotemporal spike encoding for simulating brain functions.Photonic SNN offers an ultrahigh speed and power efficiency platform for implementing high-performance neuromorphic computing.Here,we proposed a multi-synaptic photonic SNN,combining the modified remote supervised learning with delayweight co-training to achieve pattern classification.The impact of multi-synaptic connections and the robustness of the network were investigated through numerical simulations.In addition,the collaborative computing of algorithm and hardware was demonstrated based on a fabricated integrated distributed feedback laser with a saturable absorber(DFB-SA),where 10 different noisy digital patterns were successfully classified.A functional photonic SNN that far exceeds the scale limit of hardware integration was achieved based on time-division multiplexing,demonstrating the capability of hardware-algorithm co-computation.
基金Project(51571191)supported by the National Natural Science Foundation of ChinaProject(NY 20150102)supported by the National Energy Administration Program of China
文摘The phase precipitation behavior and tensile properties of an as-cast Ni-based alloy,IN617B alloy,after solution heat treatment and long-term aging treatment were investigated.Ti(C,N),M6C and M23C6 are the primary precipitates in as-cast microstructure.After solution heat treatment,most of carbides dissolve into the matrix except a few fine Ti(C,N)within grains.During long-term aging at 700°C,the phase precipitation behaviors of the alloy are characterized as follows:(1)M23C6 carbides at grain boundaries(GBs)transform from film-like shape to cellular shape and gradually coarsen due to the decrease of the surface energy and element aggregation to GBs;(2)M23C6 carbides within grains have a bar-like morphology with a preferential growth direction[110]and have a cube-on-cube coherent orientation relationship with the matrixγ;(3)γ?particles inhibit the coarsening of M23C6 within grains by constraining the diffusion of formation elements.Furthermore,the tensile strength of the alloy obviously increases,but the ductility significantly decreases after the aging for 5000 h.The alloy has a relatively stable microstructure which guarantees the excellent tensile properties during long-term aging.
文摘IN617B nickel-base superalloy is considered as a good candidate material in 700℃advanced ultrasupercritical coal-fired power plants.The effect of Ta addition on solidification microstructure and element segregation of IN617B alloy was investigated by OM,SEM,TEM,EDS,EPMA and thermodynamic calculation.The results showed that the solidification microstructure exhibited a dendritic segregation pattern with many primary carbides distributed in interdendritic regions,such as network M_(6)C,lath M_(23)C_(6) and granular Ti(C,N).The addition of Ta promoted the precipitation of Ta-rich MC significantly inhibiting the precipitation of M_(6)C and M_(23)C_(6),and reduced the segregation degree of Al,Mo and Ti alloying elements.The addition of Ta decreased the melting temperature of MC carbide,but did not impact the solidification path,that was,L→γmatrix→MC or Ti(C,N)→M_(6)C→M_(23)C_(6),where MC and Ti(C,N)tended to form symbiotic microstructure with M_(6)C.This study will provide theoretical basis and data support for the alloy optimization and casting structure control of IN617B nickel-based superalloy.
基金financially supported by the National Natural Science Foundation of China (51702063)Ministry of Science and Technology of China (No. 2015CB251103)+2 种基金the Science & Technology Department of Jilin Province (No. 20140520093JH)the Open Project of State Key Laboratory of Superhard Materials (Jilin University, No. 201513)the Fundamental Research Funds for the Central Universities (No. GK2100260182)
文摘Two-dimensional(2D)metal carbides,MXene,present the promising application for the energy storage system.Among the MXene family,Ti_2CT_xas the lightest material,shows its unique electrochemical performance.Herein,Ti_2CT_xis synthesized by selective etching Al layer from the Ti_2Al C.With the optimized HF treating condition,Ti_2CT_xdisplays high volumetric capacitance and remarkable rate ability.Moreover,the Ti_2CT_x//Ti_2CT_xsymmetric supercapacitor is designed and assembled,which presents capable capacitance,outstanding rate performance and excellent cycling performance.The remarkable electrochemical performance is attributed to its 2D structure and high electronic conductivity.This work demonstrates the potential application of the Ti_2CT_xfor the supercapacitors and provides a template to design highperformance supercapacitors with 2D electrode materials.
基金financially supported by the Shanghai Science and Technology Committee Innovation Grant(Nos.17JC1400600 and 17JC1400603)the Distinguished Professor Program of Shanghai University of Engineering Science。
文摘Laser shock peening(LSP)is an attractive post-processing method to tailor surface microstructure and enhance mechanical performances of additive manufactured(AM)components.The effects of multiple LSP treatments on the microstructure and mechanical properties of Ti-6Al-4V part produced by electron beam melting(EBM),as a mature AM process,were studied in this work.Microstructure,surface topography,residual stress,and tensile performance of EBM-manufactured Ti-6Al-4V specimens were systematically analyzed subjected to different LSP treatments.The distribution of porosities in EBM sample was assessed via X-ray computed tomography.The results showed that EBM samples with two LSP treatments possessed a lower porosity value of 0.05%compared to the value of 0.08%for the untreated samples.The strength of EBM samples with two LSP treatments was remarkably raised by 12%as compared with the as-built samples.The grains ofαphase were refined in near-surface layer,and a dramatic increase in the depth and magnitude of compressive residual stress(CRS)was achieved in EBM sample with multiple LSP treatments.The grain refinement ofαphase and CRS with larger depth were responsible for the strength enhancement of EBM samples with two LSP treatments.
基金supported by the CAS President’s International Fellowship Initiative (2016PT028)the National Natural Science Foundation of China (21273225 and 21403219)~~
文摘Metal(Al,Ti,Zr)triflate grafted mesoporous SBA‐15(AlTf/S,TiTf/S,ZrTf/S)samples were synthesizedas inexpensive solid acid materials by a simple one‐pot‐two‐step synthesis methodology.These materials were characterized by X‐ray diffraction,N2‐sorption,thermogravimetric analysis,Fourier transform infrared spectroscopy(FT‐IR),in‐situ pyridine FT‐IR spectroscopy,and elementalanalysis.ZrTf/S was found to be a highly efficient and reusable solid acid catalyst for ring opening ofepoxides with amines and alcohols and producedβ‐amino alcohols andβ‐alkoxy alcohols respectivelyunder ambient reaction conditions.The ZrTf/S catalyst showed the highest activity,whichwas attributed to its high acidity compared with that of the Ti and Al containing samples.
基金Wencheng Wu and Yinying Pu contributed equally to this work.We greatly acknowledge the financial support from CAMS Innovation Fund for Medical Sciences(No.2021-I2M-5-012)National Natural Science Foundation of China(No.21835007)+2 种基金Key Research Program of Frontier Sciences,Chinese Academy of Sciences(No.ZDBS-LY-SLH029)Basic Research Program of Shanghai Municipal Government(No.21JC1406000)China National Postdoctoral Program for Innovative Talents(No.BX20220318).
文摘The low immunogenicity of tumors remains one of the major limitations of cancer immunotherapy.Herein,we report a bacterial metabolisminitiated and photothermal-enhanced nanocatalytic therapy strategy to completely eradicate primary tumor by triggering highly effective antitumor immune responses.Briefly,a microbiotic nanomedicine,designated as Cu_(2)O@ΔSt,has been constructed by conjugating PEGylated Cu_(2)O nanoparticles on the surface of an engineered Salmonella typhimurium strain(ΔSt).Owing to the natural hypoxia tropism ofΔSt,Cu_(2)O@ΔSt could selectively colonize hypoxic solid tumors,thus minimizing the adverse effects of the bacteria on normal tis-sues.Upon bacterial metabolism within the tumor,Cu_(2)O@ΔSt generates H_(2)S gas and other acidic substances in the tumor microenvironment(TME),which will in situ trigger the sulfidation of Cu_(2)O to form CuS facilitating tumor-specific photothermal therapy(PTT)under local NIR laser irradiation on the one hand.Meanwhile,the dissolved Cu+ions from Cu_(2)O into the acidified TME enables the nanocatalytic tumor therapy by catalyzing the Fenton-like reaction of decom-posing endogenous H_(2)O_(2) into cytotoxic hydroxyl radicals(·OH)on the other hand.Such a bacterial metabolism-triggered PTT-enhanced nanocatalytic treatment could effectively destroy tumor cells and induce a massive release of tumor antigens and damage-associated molecular patterns,thereby sensitizing tumors to checkpoint blockade(ICB)therapy.The combined nanocatalytic and ICB therapy results in the much-inhibited growth of distant and metastatic tumors,and more importantly,induces a powerful immunological memory effect after the primary tumor ablation.
文摘In this paper,we have developed a highly efficient method for the direct preparation of propylene carbonate from propylene and carbon dioxide（CO2） using quaternary ammonium heteropolyphosphatotungstate–quaternary ammonium halide catalytic system with anhydrous hydrogen peroxide as an oxidant through one-pot two-step process.The effects of the amount of tetrabutylammonium bromide（TBAB）,the concentration of hydrogen peroxide and other reaction conditions were investigated.The catalyst system gave an optimum propylene oxide yield（91%） at75°C in oxidation step and the highest propylene carbonate yield（99%） at 140°C and 3.0 MPa in cycloaddition step.Based on the results,a reaction mechanism has been proposed.
基金supported by the National Natural Science Foundation of China,No.81471854
文摘Atorvastatin, a lipid-lowering medication, provides neuroprotective effects, although the precise mechanisms of action remain unclear. Our previous studies confirmed activated autophagy following spinal cord injury, which was conducive to recovery of neurological functions. We hypothesized that atorvastatin could also activate autophagy after spinal cord injury, and subsequently improve recovery of neurological functions. A rat model of spinal cord injury was established based on the Allen method. Atorvastatin（5 mg/kg） was intraperitoneally injected at 1 and 2 days after spinal cord injury. At 7 days post-injury, western blot assay, reverse transcription-polymerase chain reaction, and terminal deoxynucleotidyl transferase-mediated dU TP nick-end labeling（TUNEL） staining results showed increased Beclin-1 and light chain 3B gene and protein expressions in the spinal cord injury ＋ atorvastatin group. Additionally, caspase-9 and caspase-3 expression was decreased, and the number of TUNEL-positive cells was reduced. Compared with the spinal cord injury ＋ saline group, Basso, Beattie, and Bresnahan locomotor rating scale scores significantly increased in the spinal cord injury ＋ atorvastatin group at 14–42 days post-injury. These findings suggest that atorvastatin activated autophagy after spinal cord injury, inhibited apoptosis, and promoted recovery of neurological function.
基金supported by the National Nature Science Foundation of China, No. 39970651a Foundation from China Medical University
文摘Disrupted-in-Schizophrenia 1 is a susceptibility gene for schizophrenia and other psychiatric disorders. Developmental lead exposure can cause neurological disorders similar to hyperactivity disorder, dyslexia and schizophrenia. In the present study, we examined the impact of developmental lead exposure, administered in vitro and in vivo, on hippocampal Disrupted-In- Schizophrenia 1 expression. Our results show that in cultured hippocampal neurons, in vitro exposure to 0.1-10 pM lead, inhibited neurite growth and increased Disrupted-In-Schizophrenia 1 mRNA and protein expression dose-dependently. In addition, blood lead levels in mice were increased with increasing mouse maternal lead （0.01-1 mM） exposure. Hippocampal neurons from these mice showed a concomitant increase in Disrupted-in-Schizophrenia 1 mRNA and protein expression. Overall our findings suggest that in vivo and in vitro lead exposure increases Disrupted-In-Schizophrenia 1 expression in hippocampal neurons dose-dependently, and consequently may influence synapse formation in newborn neurons.
基金National Natural Science Foundation of China,No.81801005 and No.81870795and Jilin Provincial Development and Reform Commission,No.2018-33-05.
文摘BACKGROUND Hemifacial microsomia(HFM)is the second most common craniofacial congenital anomaly following cleft lip and palate.Because of the various phenotypic spectra and the severity of the deformity,a wide range of treatment approaches have been proposed.Recently,the surgery-first approach(SFA)was introduced to treat mild to moderate HFM,and it yielded a balanced facial appearance.The SFA not only promotes rapid improvement in facial aesthetics but also considerably reduces the overall treatment time.CASE SUMMARY A female patient,aged 25 years old,sought orthodontic treatment with the chief complaint of dental and facial asymmetry.After a comprehensive physical examination and imaging analysis were performed,the patient was diagnosed with mild HFM that was primarily attributed to unilateral abnormal development of the maxilla-mandibular.The SFA was carried out to correct the skeletal deformity.The palatal suture was used as the midline of the maxilla in the surgical plan to center the maxilla,and the chin was also properly positioned to obtain a relatively symmetrical facial appearance.Four weeks after the surgery,the patient was referred for postsurgical orthodontics to decompensate the dentition and stabilize the occlusion.After 20 mo of treatment,all orthodontic appliances were removed.The posttreatment photographs of the patient and her smile confirmed good aesthetic and occlusal results.CONCLUSION Mild HFM can be corrected by SFA,which not only promotes rapid improvement in facial aesthetics but also considerably reduces the overall treatment time.
基金supported by grants from the National Natural Science Foundation of China(Grant No.71173200)the Strategic Research Center for Oil and Gas Resources,Ministry of Land and Resources of the People's Republic of China(Grant No.2014BJYQ03)
文摘Crude oil is the world＇s leading fuel, and its prices have a big impact on the global environment, economy as well as oil exploration and exploitation activities. Oil price forecasts are very useful to industries, governments and individuals. Although many methods have been developed for predicting oil prices, it remains one of the most challenging forecasting problems due to the high volatility of oil prices. In this paper, we propose a novel approach for crude oil price prediction based on a new machine learning paradigm called stream learning. The main advantage of our stream learning approach is that the pre- diction model can capture the changing pattern of oil prices since the model is continuously updated whenever new oil price data are available, with very small constant overhead. To evaluate the forecasting ability of our stream learning model, we compare it with three other popular oil price prediction models. The experiment results show that our stream learning model achieves the highest accuracy in terms of both mean squared prediction error and directional accuracy ratio over a variety of forecast time horizons.
基金partially supported by the Chinese Academy of Sciences through grant GJHZ 200812the National Natural Science Foundation of China (Grant Nos. 11243003, 10573022,10973015 and 11061120454)the US National Science Foundation, through grant AST-09-37523
文摘The weather at the Xinglong Observing Station, where the Guo Shou Jing Telescope （GSJT） is located, is strongly affected by the monsoon climate in north- east China. The LAMOST survey strategy is constrained by these weather patterns. We present statistics on observing hours from 2004 to 2007, and the sky brightness, seeing, and sky transparency from 1995 to 2011 at the site. We investigate effects of the site conditions on the survey plan. Operable hours each month show a strong cor- relation with season： on average there are eight operable hours per night available in December, but only one-two hours in July and August. The seeing and the sky trans- parency also vary with season. Although the seeing is worse in windy winters, and the atmospheric extinction is worse in the spring and summer, the site is adequate for the proposed scientific program of the LAMOST survey. With a Monte Carlo simulation using historical data on the site condition, we find that the available observation hours constrain the survey footprint from 22h to 16h in right ascension; the sky brightness allows LAMOST to obtain a limiting magnitude of V = 19.5 mag with S/N= 10.
基金supported by the US National Science Foundation, through grant AST-09-37523the National Natural Science Foundation of China (Grant Nos. 10573022, 10973015 and 11061120454)+1 种基金the Chinese Academy of Sciences through grant GJHZ 200812S. L. is supported by the US National Science Foundation grant AST-09-08419
文摘We describe a general target selection algorithm that is applicable to any survey in which the number of available candidates is much larger than the number of objects to be observed. This routine aims to achieve a balance between a smoothly- varying, well-understood selection function and the desire to preferentially select cer- tain types of targets. Some target-selection examples are shown that illustrate differentpossibilities of emphasis functions. Although it is generally applicable, the algorithm was developed specifically for the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE） survey that will be carried out using the Chinese Guo Shou Jing Telescope. In particular, this algorithm was designed for the portion of LEGUE targeting the Galactic halo, in which we attempt to balance a variety of science goals that require stars at fainter magnitudes than can be completely sampled by LAMOST. This algorithm has been implemented for the halo portion of the LAMOST pilot sur- vey, which began in October 2011.
基金supported by the National Natural Science Foundation of China (21773232, 21403219, 21773227)~~
文摘A convenient,expeditious,and high-efficiency protocol for the transformation of alcohols into esters using a Co-modified N-doped mesoporous carbon material（Co-N/m-C）as the catalyst is proposed.The catalyst was prepared through direct pyrolysis of a macromolecular precursor.The catalyst prepared using a pyrolysis temperature of 900°C（labeled Co-N/m-C-900） exhibited the best per-formance.The strong coordination between the ultra-dispersed cobalt species and the pyridine nitrogen as well as the large area of the mesoporous surface resulted in a high turnover frequencymethyl benzoate.This value is much higher than those of state-of-the-art transition-metal-based nanocatalysts reported in the literature.Moreover,the catalyst exhibited general applicability to various structurally diverse alcohols,including benzylic,allylic,and heterocyclic alcohols,achieving the target esters in high yields.In addition,a preliminary evaluation revealed that Co-N/m-C-900 can be used six times without significant activity loss.In general,the process was rapid,simple,and cost-effective.
基金supported in part by a grant of the Scientific Research Program of Hainan Province (ZDYF2016143), China
文摘A simple, rapid and sensitive method based on an ultra-performance liquid chromatography tandem mass spectrometry （UPLC-MS/MS） has been developed and validated for the determination of pimavanserin in rat plasma. The analyte was extracted by protein precipitation with methanol and separated on an ACQUITY BEH C18 column （100 mm × 2.1 mm, 1.7μm; Waters, USA）, with an isocratic elution of acetonitrile-water containing 10 mM ammonium acetate （70：30, v/v）, at a flow rate of 0.2 mL/min for 2.5 rain. The analyte and clarithromyein （the internal standard） were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 428.2 - 223.0 for pimavanserin and m/z 748.5 - 589.5 for clarithromycin. Relative coefficient （r） for the calibration curve was more than 0.9980. The intra-day and inter-day precisions （relative standard deviation, RSD%） were less than 13.3% and 10.5%, respectively, and the accuracy （relative error, RE%） was within ± 11.5%. The analytical method was successfully applied to a routine pharmacokinetic study of pimavanserin in rats after oral administration at the dose of 10 mg/kg.
