The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their perform...The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their performance is often impeded by weak adsorption of oxygen species,leading to a 2e^(-)pathway that negatively affects fuel cell discharge efficiency.Here,we engineered a high-density cobalt active center catalyst,coordinated with nitrogen and sulfur atoms on a porous carbon substrate.Both experimental and theoretical analyses highlighted the role of sulfur atoms as electron donors,disrupting the charge symmetry of the original Co active center and promoting enhanced interaction with Co 3d orbitals.This modification improves the adsorption of oxygen and reaction intermediates during ORR,significantly reducing the production of hydrogen peroxide(H_(2)O_(2)).Remarkably,the optimized catalyst demonstrated superior fuel cell performance,with peak power densities of 1.32 W cm^(-2) in oxygen and 0.61 W cm^(-2) in air environments,respectively.A significant decrease in H_(2)O_(2) by-product accumulation was observed during the reaction process,reducing catalyst and membrane damage and consequently improving fuel cell durability.This study emphasizes the critical role of coordination symmetry in Co/N/C catalysts and proposes an effective strategy to enhance fuel cell performance.展开更多
Conventional lithium-ion batteries(LIBs)with liquid electrolytes are challenged by their big safety concerns,particularly used in electric vehicles.All-solid-state batteries using solid-state electrolytes have been pr...Conventional lithium-ion batteries(LIBs)with liquid electrolytes are challenged by their big safety concerns,particularly used in electric vehicles.All-solid-state batteries using solid-state electrolytes have been proposed to significantly improve safety yet are impeded by poor interfacial solid–solid contact and fast interface degradation.As a compromising strategy,in situ solidification has been proposed in recent years to fabricate quasi-solid-state batteries,which have great advantages in constructing intimate interfaces and cost-effective mass manufacturing.In this work,quasi-solid-state pouch cells with high loading electrodes(≥3 m Ah cm^(-2))were fabricated via in situ solidification of poly(ethylene glycol)diacrylate-based polymer electrolytes(PEGDA-PEs).Both single-layer and multilayer quasi-solid-state pouch cells(2.0 Ah)have demonstrated stable electrochemical performance over500 cycles.The superb electrochemical stability is closely related to the formation of robust and compatible interphase,which successfully inhibits interfacial side reactions and prevents interfacial structural degradation.This work demonstrates that in situ solidification is a facile and cost-effective approach to fabricate quasi-solid-state pouch cells with both excellent electrochemical performance and safety.展开更多
This paper examines national urban agglomerations by taking factor flows as the focal point as the research subject.By dividing the stages of urban agglomeration development,a comprehensive framework of urban shrinkag...This paper examines national urban agglomerations by taking factor flows as the focal point as the research subject.By dividing the stages of urban agglomeration development,a comprehensive framework of urban shrinkage is constructed,encompassing economic,population,and social shrinkage.The study explores the spatial distribution characteristics of urban shrinkage during different stages of urban agglomeration and investigates the influencing factors using a geographic detector model.The findings reveal that urban shrinkage within urban agglomerations is widely spread,predominantly in peripheral areas.During the diffusion stage,urban shrinkage is scattered,with population shrinkage concentrated in peripheral regions,economic shrinkage concentrated on old industrial cities,and social shrinkage concentrated on the northeast.The outcomes of the geographic detector model indicate that traffic flow,capital flow,information flow,node importance,network connectivity,government investment,openness,and environmental regulations all play significant roles in shaping the spatial distribution of urban shrinkage.展开更多
AIM: To demonstrate an inexpensive method for typing gastric cancer related single nucleotide polymorphisms (SNPs) using whole blood or paper-dried blood as starting materials. METHODS: PCR amplification is directly c...AIM: To demonstrate an inexpensive method for typing gastric cancer related single nucleotide polymorphisms (SNPs) using whole blood or paper-dried blood as starting materials. METHODS: PCR amplification is directly carried out from the whole blood or paper-dried blood sample without any DNA extraction step. Before PCR, a blood sample, four primers, and all of biological reagents necessary for PCR were added at a time; After PCR, the amplified products were directly separated by slab gel electrophoresis or microchip CE without any purification. SNP typing was performed by tetra-primer PCR with two inner primers specific to each allele and two outer primers defining the length of allele-specific amplicons. Genotypes were directly discriminated by the size of amplicons specific to each allele, thereby avoiding any post-PCR process. RESULTS: Using a special PCR buffer, inhibitory substances in blood (including the anticoagulant in blood) and filter paper were effectively suppressed; a 'true' single-tube-genotyping is thus realized. We successfully determined genotypes IL-1B-511 and IL-1B-31 polymorphisms at the gene IL-1B by using whole-blood and paper-dried blood samples as starting materials respectively. The method is so sensitive that 0.5-1.0μL of blood sample is enough to give a satisfactory typing results. The genotyping results were confirmed by RFLP-PCR using purified genome DNA, indicating that amplification specificity was not affected by inhibitory components (including coagulants) in blood or filter paper. CONCLUSION: Compared with SNP typing methods based on purified DNA, the proposed method is labor saving, simple, inexpensive, and less cross-contaminated. It is promising to use this method to type other SNPs.展开更多
Seasonal frozen soil accounts for about 53.50%of the land area in China.Frozen soil is a complex multiphase system where ice,water,soil,and air coexist.The distribution and migration of salts in frozen soil during soi...Seasonal frozen soil accounts for about 53.50%of the land area in China.Frozen soil is a complex multiphase system where ice,water,soil,and air coexist.The distribution and migration of salts in frozen soil during soil freezing are notably different from those in unfrozen soil areas.However,little knowledge is available about the process and mechanisms of salt migration in frozen soil.This study explores the mechanisms of salt migration at the ice-liquid interface during the freezing of pore fluids through batch experiments.The results are as follows.The solute concentrations of liquid and solid phases at the ice-liquid interface(C*_(L),C*_(S))gradually increased at the initial stage of freezing and remained approximately constant at the middle stage.As the ice-liquid interface advanced toward the system boundary,the diffusion of the liquid phase was blocked but the ice phase continued rejecting salts.As a result,C*_(L)and C*_(S)rapidly increased at the final stage of freezing.The distribution characteristics of solutes in ice and the liquid phases before C*_(L)and C*_(S)became steady were mainly affected by the freezing temperature,initial concentrations,and particle-size distribution of media(quartz sand and kaolin).In detail,the lower the freezing temperature and the better the particle-size distribution of media,the higher the solute proportion in the ice phase at the initial stage of freezing.Meanwhile,the increase in concentration first promoted but then inhibited the increase of solutes in the ice phase.These results have insights and scientific significance for the tackling of climate change,the environmental protection of groundwater and soil,and infrastructure protection such as roads,among other things.展开更多
BACKGROUND: Few studies have reported the effects of early tracheotomy in acute severe asthmatic patients. We report two patients with acute severe asthma who were successfully treated with early tracheotomy. METHOD...BACKGROUND: Few studies have reported the effects of early tracheotomy in acute severe asthmatic patients. We report two patients with acute severe asthma who were successfully treated with early tracheotomy. METHODS:The two patients with acute severe asthma were retrospectively reviewed. They had been treated at the Department of Emergency and Critical Care, Renji Hospital, Shanghai Jiaotong University School of Medicine. RESULTS: They developed progressively hypercapnia and severe acidosis, and were not improved after conventional therapies. Early tracheotomy after mechanical ventilation decreased airway resistance and work of breathing, and corrected hypercapnia and acidosis. Adequate gas exchange was maintained after tracheotomy. The two patients were subsequently weaned from mechanical ventilation and discharged. CONCLUSION:Early tracheotomy could be a valuable approach in certain patients with severe asthma.展开更多
Writing is an important part of language learning and is considered the best approach to demonstrate the comprehensive language skills of students.Manually grading student essays is a time-consuming task;however,it is...Writing is an important part of language learning and is considered the best approach to demonstrate the comprehensive language skills of students.Manually grading student essays is a time-consuming task;however,it is necessary.An automated essay scoring system can not only greatly improve the efficiency of essay scoring,but also provide more objective score.Therefore,many researchers have been exploring automated essay scoring techniques and tools.However,the technique of scoring Chinese essays is still limited,and its accuracy needs to be enhanced further.To improve the accuracy of the scoring model for a Chinese essay,we propose an automated scoring approach based on a deep learning model and validate its effect by conducting two comparison experiments.The experimental results indicate that the accuracy of the proposed model is significantly higher than that of multiple linear regression(MLR),which was commonly used in the past.The three accuracy rates of the proposed model are comparable to those of the novice teacher.The root mean square error(RMSE)of the proposed model is slightly lower than that of the novice teacher,and the correlation coefficient of the proposed model is also significantly higher than that of the novice teacher.Besides,when the predicted scores are not very low or very high,the two predicted models are as good as a novice teacher.However,when the predicted score is very high or very low,the results should be treated with caution.展开更多
Space electromagnetic docking technology, free of propellant and plume contamination, offers continuous, reversible and synchronous controllability, which is widely applied in the future routine on-orbit servicing mis...Space electromagnetic docking technology, free of propellant and plume contamination, offers continuous, reversible and synchronous controllability, which is widely applied in the future routine on-orbit servicing missions. Due to the inherent nonlinearities, couplings and uncertainties of an electromagnetic force model, the dynamics and control problems of them are difficult. A new modeling approach for relative motion dynamics with intersatellite force is proposed. To resolve these control problems better, a novel nonlinear control method for soft space electro-magnetic docking is proposed, which combines merits of artificial potential function method, Lyapunov theory and extended state observer. In addition, the angular momentum management problem of space electromagnetic docking and approaches of handling it by exploiting the Earth's magnetic torque are investigated. Finally, nonlinear simulation results demonstrate the feasibility of the dynamic model and the novel nonlinear control method.展开更多
Objective To investigate the relationship between CRP, plasminogen activator inhibitor type 1 (PAI-1) levels, PAI-1 gene promoter 4G/5G polymorphism and the type of acute myocardial infarction (ST elevation myocard...Objective To investigate the relationship between CRP, plasminogen activator inhibitor type 1 (PAI-1) levels, PAI-1 gene promoter 4G/5G polymorphism and the type of acute myocardial infarction (ST elevation myocardial infarction, STEMI vs the non-ST elevation Myocardial infarction, NSTEMI). Methods One hundred seventy-six consecutive patients with AMI were included for the study, of whom 60 had STEMI and 56 had NSTEMI, and 60 adults without cardiovascular and cerebrovascular disease were selected as controls. Blood samples were obtained from patients within 6 h of AMI and the plasma PAI-1, CRP, and the gene polymorphism were measured. Results Plasma levels of PAI- 1 and CRP were higher in AMI groups, compared those in the control group, and plasma levels of PAI-1 were significantly higher in patients with STEMI compared to those with NSTEMI (80.12ng/ml VS.73.01ng/ml, P 〈0.01), while CRP levels were not significantly different between patient with STEMI and NSTEMI (3.87 ± 0.79 mg/ml VS.4.01 ±0.69mg/ml, P〉0.05). PAI-1 levels presented a significant correlation with CRP levels in the NSTEMI subjects. However, PAI-1 and CRP levels could explain the lack of a significant relationship between them in control and STEMI subjects.The frequencies of 4G/4G genotype in the AMI group were higher than those in the control group and higher in patient with STEMI than in patient with NSTEMI. Plasma levels of PAI-1 in subjects with 4G/4G genotype were significantly increased as compared to those in subjects with 4G/5G and 5G/5G genotype. Conclusions Plasma PAI-1 levels were associated with different myocardial infarction type, and PAI-1 promoter 4G/5G polymorphisms and CRP may be related to plasma PAI-1 levels展开更多
BACKGROUND Brain arteriovenous malformation(AVM),an aberrant vascular development during the intrauterine period,is traditionally considered a congenital disease.Sporadic reports of cases of de novo AVM formation in c...BACKGROUND Brain arteriovenous malformation(AVM),an aberrant vascular development during the intrauterine period,is traditionally considered a congenital disease.Sporadic reports of cases of de novo AVM formation in children and adults have challenged the traditional view of its congenital origin.CASE SUMMARY In this report,we have presented the case of a child with a de novo brain AVM.Magnetic resonance imaging and magnetic resonance angiography of the brain showed no AVM at the age of 5 years and 2 mo.Brain AVM was first detected in this child at the age of 7 years and 4 mo.The brain AVM was significantly advanced,and hemorrhage was seen for the first time at the age of 12 years and 8 mo.There was further progression in the AVM,and hemorrhage occurred again at the age of 13 years and 5 mo.Genetic analysis of this patient revealed a mutation in the NOTCH2(p.Asp473 Val)gene.CONCLUSION In short,our case has once again confirmed the view that brain AVM is an acquired disease and is the result of the interaction of genes,environment,and molecules.展开更多
This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interfer...This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interference can have a significant impact on the appropriate test location that yields the exact substation ground impedance. Applying a specific percentage rule such as the 61.8% rule for uniform soils to obtain the true ground impedance may lead to unacceptable errors for large grounding systems. This poses significant problems when attempting to validate a design based on raw test data that are interpreted using approximate methods to evaluate substation ground impedance, and determine ground potential rise (GPR), touch and step voltages. Advanced measurement methodologies and modern software packages were used to obtain and effectively analyze fall of potential test data, compute fault current distribution, and evaluate touch and step voltages for this large substation. Fault current distribution between the grounding system and other metallic paths were computed to determine the portion of fault current discharged in the grounding system. The performance of the grounding system, including its GPR and touch and step voltages, has been accurately computed and measured, taking into account the impedance of the steel material used of the ground conductors and circulating currents within the substation grounding system.展开更多
[Objective] This study aimed to investigate the effect and mechanism of miRNA-139-Sp in the occurrence and development of colorectal cancer. [ Method] Forty SPF grade C57BL/6 male mice, including 20 miRNA-139-Sp knock...[Objective] This study aimed to investigate the effect and mechanism of miRNA-139-Sp in the occurrence and development of colorectal cancer. [ Method] Forty SPF grade C57BL/6 male mice, including 20 miRNA-139-Sp knockout (KO) mice and 20 wild-type (WT) mice, were selected to establish the animal models of colorectal cancer. The occurrence and development of colorectal cancer in mice were observed. H&E staining was performed to analyze histopatho- logical changes and immunohistochemical expression of proliferative proteins. The level of apoptosis of tumor cells was detected by TUNEL assay. [ Result] During cancer induction, the body weight of mice in miR-139-Sp KO group declined more significantly and recovered slower with lower survival rate compared with that in WT group. The colons of mice in miR-139-Sp KO group were shorter with more tumors than those in WT group. In addition, mice in KO group exhibited rapider progression of colorectal cancer, higher deterioration degree and lower apoptosis level of tumor cells. [ Conclusion] miRNA-139-Sp plays an important role in the occurrence and development of colorectal cancer, which can not only inhibit tumor degeneration and proliferation of tumor cells, but also promote the apoptosis of tumor cells.展开更多
The path of system innovation is crucial for economic evolution of country. In the process of carrying out and promoting marketing economic system transition, China objectively and historically sticks to the path of s...The path of system innovation is crucial for economic evolution of country. In the process of carrying out and promoting marketing economic system transition, China objectively and historically sticks to the path of system innovation. This has significant theory value and strategic meaning for breaking down the lock-in and following the principle of path-dependence so as to realize the rapid development of economy.展开更多
Saccharides are a sort of ubiquitous and vital molecules within the whole life.However,the application of saccharides analysis with matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)is restricted ...Saccharides are a sort of ubiquitous and vital molecules within the whole life.However,the application of saccharides analysis with matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)is restricted by their low ionization efficiency and the instability of the sialic acid fraction.Derivatization strategy based on nonreductive amination provides a good solution,however,this is often time consuming and may result in sample loss due to removal of excessive derivatization reagents.Herein,hydralazine(HZN)was utilized as a reactive matrix for labeling reducing saccharides directly on MALDI target which eliminated tedious sample preparation and avoided sample loss.After optimization,effective and reproducible on-MALDI-target derivatization of neutral and acidic saccharides was achieved in both positive and negative modes.Compared with 2,5-dihydroxybenzoic acid(DHB)and 9-aminoacridine(9-AA),HZN improved the detection sensitivity of reducing saccharides and provided more abundant fragment ions in MS/MS analysis.Moreover,26 kinds of neutral glycans and 5 kinds of sialic glycans were identified from ovalbumin(OVA)and bovine fetuin,respectively.Combined with the statistical models,this strategy could be used to distinguish and predict samples of 6 brands of beer,and discriminate 2 kinds of beer fermentation modes.In addition,HZN was applied for quantitative analysis of glucose in urine samples,and the obtained urine glucose concentrations of diabetic patients were consistent with the clinical test results,showing the potential of qualitative and quantitative analysis of reducing saccharides in complex samples.展开更多
Superconducting electrodynamic suspension (EDS) presents numerous advantages, including large suspension gaps, high lift-to-drag ratios, and lower requirements for track irregularities. Recent advancements in supercon...Superconducting electrodynamic suspension (EDS) presents numerous advantages, including large suspension gaps, high lift-to-drag ratios, and lower requirements for track irregularities. Recent advancements in superconducting materials have further enhanced the feasibility of this technology, and hence multiple research institutions are actively developing and improving this high-speed rail technology. Superconducting EDS achieves passive suspension and guidance by the interaction between ground null-flux coils and onboard superconducting magnets, forming an electromechanical coupled system. Thus, electromechanical coupling modeling and equivalent experimental methods are essential in evaluating and optimizing this system. This article reviews the research on dynamic characteristics analysis of superconducting EDS, focusing on modeling and experimental methods. Firstly, it revisits the development history of superconducting EDS and the new opportunities brought by advancements in superconducting materials. Secondly, it discusses various modeling approaches for the suspension system, emphasizing their benefits and limitations. Thirdly, it describes equivalent experimental methods and their respective application scenarios. Then, it reviews important conclusions and possible optimization methods related to dynamic performance and electromechanical coupling research. Additionally, the sliding window method is introduced to improve computational efficiency in vehicle dynamics modeling. This article provides insights into the current state and future directions of superconducting EDS research, serving as a valuable reference for researchers and engineers.展开更多
Cardiovascular disease(CVD)is a global health problem and is thought to be responsible for almost half of all deaths in the world.Nevertheless,currently available diagnostic methods for CVD are strongly depended on cl...Cardiovascular disease(CVD)is a global health problem and is thought to be responsible for almost half of all deaths in the world.Nevertheless,currently available diagnostic methods for CVD are strongly depended on clinical observation and monitoring,which commonly result in false diagnosis.Herein,an attractive strategy of a metal-organic framework(MOF)nanofilm-based laser desorption/ionization mass spectrometry(LDI-MS)was developed for enhancing serum metabolic profiling,which could provide precise diagnosis and molecular subtyping of CVD.The porous MOF nanofilm fabricated on indium-tin oxide(ITO)glass possessed enhanced ionization efficiency and size-exclusion effect,which endowed it as substrate with high sensitivity and selectivity for serum metabolites.Furthermore,the MOF nanofilm with uniform surface and high orientation provided high-quality and high-reproducibility serum metabolic profiles(SMPs)without any tedious pretreatment.Further analysis of extracted serum metabolic fingerprints could successfully distinguish patients with CVD from healthy controls and also differentiate two major subtypes of CVD.This work not only extends the application of MOF nanofilm as an attractive MS probe,but also provide an alternative way for precise diagnosis of CVD in molecular level.展开更多
Irrigation has a significant impact on N_(x)O(N_(2)O and NO)emissions from cultivated land,yet the N_(2)O or NO emission among the irrigation lower limits under different irrigation modes has not been well compared.In...Irrigation has a significant impact on N_(x)O(N_(2)O and NO)emissions from cultivated land,yet the N_(2)O or NO emission among the irrigation lower limits under different irrigation modes has not been well compared.In an irrigated lettuce field,three DR(drip irrigation)lower limits were designed,including 75%(DR1),65%(DR2)and 55%(DR3)field capacity,and one FI(furrow irrigation)lower limit(65%field capacity).The N_(2)O and NO emission fluxes and soil nitrogen(N)forms were determined,and the linear correlation between these indicators was analyzed.Results showed that under the same irrigation regime,the N_(2)O and NO emissions from furrow irrigation treatment increased by 36.8%and 45.2%respectively compared to that from drip irrigation treatment.The cumulative N_(2)O and NO emissions under DR3 were 30.2%and 28.6%higher than under DR1,respectively.Moreover,DR1 was also the lowest among the four treatments in soil-N concentration.The N_(2)O and NO emission fluxes were more correlated to soil NH_(4)^(+)-N(r=0.88 and 0.76)or NO_(2)^(-)-N(r=0.90 and 0.80)concentration than soil-N and soluble organic N,indicating that N_(2)O and NO were mainly produced by the soil nitrification process.When the irrigation regime was the same,N_(2)O and NO emissions were lower with drip irrigation than with furrow irrigation.Besides,drip irrigation with small quota but high frequency reduced N_(2)O and NO emission compared to that with large quota but low frequency.展开更多
Underground liquified natural gas(LNG)storage is essential in guaranteeing national energy strategic reserves,and its construction is being accelerated.The stability of surrounding rock of underground LNG storage cave...Underground liquified natural gas(LNG)storage is essential in guaranteeing national energy strategic reserves,and its construction is being accelerated.The stability of surrounding rock of underground LNG storage caverns under stress-low temperature coupling effect is the key factor determining the feasibility of LNG storage.First,a mathematical model used for controlling the stress-low temperature coupling and the processes of rock damage evolution is given,followed by a 2-D numerical execution process of the mathematical model mentioned above described based on Comsol Multiphysics and Matlab code.Finally,a series of 2-D simulations are performed to study the influence of LNG storage cavern layout,burial depth,temperature and internal pressure on the stability of surrounding rocks of these underground storage caverns.The results indicate that all the factors mentioned above affect the evolution of deformation and plastic zone of surrounding rocks.The research results contribute to the engineering design of underground LNG storage caverns.展开更多
基金financially National Natural Science Foundation of China (22288102, 22172134, U1932201, U2032202)Science and Technology Planning Project of Fujian Province (2022H0002)support from the EPSRC (EP/W03784X/1)。
文摘The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their performance is often impeded by weak adsorption of oxygen species,leading to a 2e^(-)pathway that negatively affects fuel cell discharge efficiency.Here,we engineered a high-density cobalt active center catalyst,coordinated with nitrogen and sulfur atoms on a porous carbon substrate.Both experimental and theoretical analyses highlighted the role of sulfur atoms as electron donors,disrupting the charge symmetry of the original Co active center and promoting enhanced interaction with Co 3d orbitals.This modification improves the adsorption of oxygen and reaction intermediates during ORR,significantly reducing the production of hydrogen peroxide(H_(2)O_(2)).Remarkably,the optimized catalyst demonstrated superior fuel cell performance,with peak power densities of 1.32 W cm^(-2) in oxygen and 0.61 W cm^(-2) in air environments,respectively.A significant decrease in H_(2)O_(2) by-product accumulation was observed during the reaction process,reducing catalyst and membrane damage and consequently improving fuel cell durability.This study emphasizes the critical role of coordination symmetry in Co/N/C catalysts and proposes an effective strategy to enhance fuel cell performance.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC),Canada Research Chair Program(CRC),Canada Foundation for Innovation(CFI),Ontario Research Fund(ORF),China Automotive Battery Research Institute Co.,Ltd.,Glabat Solid-State Battery Inc.,Canada Light Source(CLS)at the University of Saskatchewan,Interdisciplinary Development Initiatives(IDI)by Western University,and University of Western Ontariothe support from Mitacs Accelerate Program(IT13735)the funding support from Banting Postdoctoral Fel owship(BPF—180162)
文摘Conventional lithium-ion batteries(LIBs)with liquid electrolytes are challenged by their big safety concerns,particularly used in electric vehicles.All-solid-state batteries using solid-state electrolytes have been proposed to significantly improve safety yet are impeded by poor interfacial solid–solid contact and fast interface degradation.As a compromising strategy,in situ solidification has been proposed in recent years to fabricate quasi-solid-state batteries,which have great advantages in constructing intimate interfaces and cost-effective mass manufacturing.In this work,quasi-solid-state pouch cells with high loading electrodes(≥3 m Ah cm^(-2))were fabricated via in situ solidification of poly(ethylene glycol)diacrylate-based polymer electrolytes(PEGDA-PEs).Both single-layer and multilayer quasi-solid-state pouch cells(2.0 Ah)have demonstrated stable electrochemical performance over500 cycles.The superb electrochemical stability is closely related to the formation of robust and compatible interphase,which successfully inhibits interfacial side reactions and prevents interfacial structural degradation.This work demonstrates that in situ solidification is a facile and cost-effective approach to fabricate quasi-solid-state pouch cells with both excellent electrochemical performance and safety.
基金National Social Science Fund Project(22BZ039)Henan Province Science and Technology Tackling Key Problems Soft Science Project(222400410186)。
文摘This paper examines national urban agglomerations by taking factor flows as the focal point as the research subject.By dividing the stages of urban agglomeration development,a comprehensive framework of urban shrinkage is constructed,encompassing economic,population,and social shrinkage.The study explores the spatial distribution characteristics of urban shrinkage during different stages of urban agglomeration and investigates the influencing factors using a geographic detector model.The findings reveal that urban shrinkage within urban agglomerations is widely spread,predominantly in peripheral areas.During the diffusion stage,urban shrinkage is scattered,with population shrinkage concentrated in peripheral regions,economic shrinkage concentrated on old industrial cities,and social shrinkage concentrated on the northeast.The outcomes of the geographic detector model indicate that traffic flow,capital flow,information flow,node importance,network connectivity,government investment,openness,and environmental regulations all play significant roles in shaping the spatial distribution of urban shrinkage.
基金Supported by National Natural Science Foundation of China,No. 30270368
文摘AIM: To demonstrate an inexpensive method for typing gastric cancer related single nucleotide polymorphisms (SNPs) using whole blood or paper-dried blood as starting materials. METHODS: PCR amplification is directly carried out from the whole blood or paper-dried blood sample without any DNA extraction step. Before PCR, a blood sample, four primers, and all of biological reagents necessary for PCR were added at a time; After PCR, the amplified products were directly separated by slab gel electrophoresis or microchip CE without any purification. SNP typing was performed by tetra-primer PCR with two inner primers specific to each allele and two outer primers defining the length of allele-specific amplicons. Genotypes were directly discriminated by the size of amplicons specific to each allele, thereby avoiding any post-PCR process. RESULTS: Using a special PCR buffer, inhibitory substances in blood (including the anticoagulant in blood) and filter paper were effectively suppressed; a 'true' single-tube-genotyping is thus realized. We successfully determined genotypes IL-1B-511 and IL-1B-31 polymorphisms at the gene IL-1B by using whole-blood and paper-dried blood samples as starting materials respectively. The method is so sensitive that 0.5-1.0μL of blood sample is enough to give a satisfactory typing results. The genotyping results were confirmed by RFLP-PCR using purified genome DNA, indicating that amplification specificity was not affected by inhibitory components (including coagulants) in blood or filter paper. CONCLUSION: Compared with SNP typing methods based on purified DNA, the proposed method is labor saving, simple, inexpensive, and less cross-contaminated. It is promising to use this method to type other SNPs.
基金This research was financially supported by the National Natural Science Foundation of China(41572225)project of China Geological Survey(DD20189662,DD20211256).
文摘Seasonal frozen soil accounts for about 53.50%of the land area in China.Frozen soil is a complex multiphase system where ice,water,soil,and air coexist.The distribution and migration of salts in frozen soil during soil freezing are notably different from those in unfrozen soil areas.However,little knowledge is available about the process and mechanisms of salt migration in frozen soil.This study explores the mechanisms of salt migration at the ice-liquid interface during the freezing of pore fluids through batch experiments.The results are as follows.The solute concentrations of liquid and solid phases at the ice-liquid interface(C*_(L),C*_(S))gradually increased at the initial stage of freezing and remained approximately constant at the middle stage.As the ice-liquid interface advanced toward the system boundary,the diffusion of the liquid phase was blocked but the ice phase continued rejecting salts.As a result,C*_(L)and C*_(S)rapidly increased at the final stage of freezing.The distribution characteristics of solutes in ice and the liquid phases before C*_(L)and C*_(S)became steady were mainly affected by the freezing temperature,initial concentrations,and particle-size distribution of media(quartz sand and kaolin).In detail,the lower the freezing temperature and the better the particle-size distribution of media,the higher the solute proportion in the ice phase at the initial stage of freezing.Meanwhile,the increase in concentration first promoted but then inhibited the increase of solutes in the ice phase.These results have insights and scientific significance for the tackling of climate change,the environmental protection of groundwater and soil,and infrastructure protection such as roads,among other things.
文摘BACKGROUND: Few studies have reported the effects of early tracheotomy in acute severe asthmatic patients. We report two patients with acute severe asthma who were successfully treated with early tracheotomy. METHODS:The two patients with acute severe asthma were retrospectively reviewed. They had been treated at the Department of Emergency and Critical Care, Renji Hospital, Shanghai Jiaotong University School of Medicine. RESULTS: They developed progressively hypercapnia and severe acidosis, and were not improved after conventional therapies. Early tracheotomy after mechanical ventilation decreased airway resistance and work of breathing, and corrected hypercapnia and acidosis. Adequate gas exchange was maintained after tracheotomy. The two patients were subsequently weaned from mechanical ventilation and discharged. CONCLUSION:Early tracheotomy could be a valuable approach in certain patients with severe asthma.
基金This work is supported by the National Science Foundation of China(No.61532008No.61572223)+1 种基金the National Key Research and Development Program of China(No.2017YFC0909502)the Ministry of Education of Humanities and Social Science project(No.20YJCZH046).
文摘Writing is an important part of language learning and is considered the best approach to demonstrate the comprehensive language skills of students.Manually grading student essays is a time-consuming task;however,it is necessary.An automated essay scoring system can not only greatly improve the efficiency of essay scoring,but also provide more objective score.Therefore,many researchers have been exploring automated essay scoring techniques and tools.However,the technique of scoring Chinese essays is still limited,and its accuracy needs to be enhanced further.To improve the accuracy of the scoring model for a Chinese essay,we propose an automated scoring approach based on a deep learning model and validate its effect by conducting two comparison experiments.The experimental results indicate that the accuracy of the proposed model is significantly higher than that of multiple linear regression(MLR),which was commonly used in the past.The three accuracy rates of the proposed model are comparable to those of the novice teacher.The root mean square error(RMSE)of the proposed model is slightly lower than that of the novice teacher,and the correlation coefficient of the proposed model is also significantly higher than that of the novice teacher.Besides,when the predicted scores are not very low or very high,the two predicted models are as good as a novice teacher.However,when the predicted score is very high or very low,the results should be treated with caution.
基金supported by the National Natural Science Foundation of China(11172322)
文摘Space electromagnetic docking technology, free of propellant and plume contamination, offers continuous, reversible and synchronous controllability, which is widely applied in the future routine on-orbit servicing missions. Due to the inherent nonlinearities, couplings and uncertainties of an electromagnetic force model, the dynamics and control problems of them are difficult. A new modeling approach for relative motion dynamics with intersatellite force is proposed. To resolve these control problems better, a novel nonlinear control method for soft space electro-magnetic docking is proposed, which combines merits of artificial potential function method, Lyapunov theory and extended state observer. In addition, the angular momentum management problem of space electromagnetic docking and approaches of handling it by exploiting the Earth's magnetic torque are investigated. Finally, nonlinear simulation results demonstrate the feasibility of the dynamic model and the novel nonlinear control method.
文摘Objective To investigate the relationship between CRP, plasminogen activator inhibitor type 1 (PAI-1) levels, PAI-1 gene promoter 4G/5G polymorphism and the type of acute myocardial infarction (ST elevation myocardial infarction, STEMI vs the non-ST elevation Myocardial infarction, NSTEMI). Methods One hundred seventy-six consecutive patients with AMI were included for the study, of whom 60 had STEMI and 56 had NSTEMI, and 60 adults without cardiovascular and cerebrovascular disease were selected as controls. Blood samples were obtained from patients within 6 h of AMI and the plasma PAI-1, CRP, and the gene polymorphism were measured. Results Plasma levels of PAI- 1 and CRP were higher in AMI groups, compared those in the control group, and plasma levels of PAI-1 were significantly higher in patients with STEMI compared to those with NSTEMI (80.12ng/ml VS.73.01ng/ml, P 〈0.01), while CRP levels were not significantly different between patient with STEMI and NSTEMI (3.87 ± 0.79 mg/ml VS.4.01 ±0.69mg/ml, P〉0.05). PAI-1 levels presented a significant correlation with CRP levels in the NSTEMI subjects. However, PAI-1 and CRP levels could explain the lack of a significant relationship between them in control and STEMI subjects.The frequencies of 4G/4G genotype in the AMI group were higher than those in the control group and higher in patient with STEMI than in patient with NSTEMI. Plasma levels of PAI-1 in subjects with 4G/4G genotype were significantly increased as compared to those in subjects with 4G/5G and 5G/5G genotype. Conclusions Plasma PAI-1 levels were associated with different myocardial infarction type, and PAI-1 promoter 4G/5G polymorphisms and CRP may be related to plasma PAI-1 levels
基金Supported by the Science and Technology Program of Wenzhou,China,No.Y20190145 to Huan Huangthe Beijing New Health Industry Development Foundation,No.XM2020-02-002 to Bo Yin。
文摘BACKGROUND Brain arteriovenous malformation(AVM),an aberrant vascular development during the intrauterine period,is traditionally considered a congenital disease.Sporadic reports of cases of de novo AVM formation in children and adults have challenged the traditional view of its congenital origin.CASE SUMMARY In this report,we have presented the case of a child with a de novo brain AVM.Magnetic resonance imaging and magnetic resonance angiography of the brain showed no AVM at the age of 5 years and 2 mo.Brain AVM was first detected in this child at the age of 7 years and 4 mo.The brain AVM was significantly advanced,and hemorrhage was seen for the first time at the age of 12 years and 8 mo.There was further progression in the AVM,and hemorrhage occurred again at the age of 13 years and 5 mo.Genetic analysis of this patient revealed a mutation in the NOTCH2(p.Asp473 Val)gene.CONCLUSION In short,our case has once again confirmed the view that brain AVM is an acquired disease and is the result of the interaction of genes,environment,and molecules.
文摘This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interference can have a significant impact on the appropriate test location that yields the exact substation ground impedance. Applying a specific percentage rule such as the 61.8% rule for uniform soils to obtain the true ground impedance may lead to unacceptable errors for large grounding systems. This poses significant problems when attempting to validate a design based on raw test data that are interpreted using approximate methods to evaluate substation ground impedance, and determine ground potential rise (GPR), touch and step voltages. Advanced measurement methodologies and modern software packages were used to obtain and effectively analyze fall of potential test data, compute fault current distribution, and evaluate touch and step voltages for this large substation. Fault current distribution between the grounding system and other metallic paths were computed to determine the portion of fault current discharged in the grounding system. The performance of the grounding system, including its GPR and touch and step voltages, has been accurately computed and measured, taking into account the impedance of the steel material used of the ground conductors and circulating currents within the substation grounding system.
基金Supported by Fund of Science and Technology Department of Zhejiang Province(2015C37086)
文摘[Objective] This study aimed to investigate the effect and mechanism of miRNA-139-Sp in the occurrence and development of colorectal cancer. [ Method] Forty SPF grade C57BL/6 male mice, including 20 miRNA-139-Sp knockout (KO) mice and 20 wild-type (WT) mice, were selected to establish the animal models of colorectal cancer. The occurrence and development of colorectal cancer in mice were observed. H&E staining was performed to analyze histopatho- logical changes and immunohistochemical expression of proliferative proteins. The level of apoptosis of tumor cells was detected by TUNEL assay. [ Result] During cancer induction, the body weight of mice in miR-139-Sp KO group declined more significantly and recovered slower with lower survival rate compared with that in WT group. The colons of mice in miR-139-Sp KO group were shorter with more tumors than those in WT group. In addition, mice in KO group exhibited rapider progression of colorectal cancer, higher deterioration degree and lower apoptosis level of tumor cells. [ Conclusion] miRNA-139-Sp plays an important role in the occurrence and development of colorectal cancer, which can not only inhibit tumor degeneration and proliferation of tumor cells, but also promote the apoptosis of tumor cells.
文摘The path of system innovation is crucial for economic evolution of country. In the process of carrying out and promoting marketing economic system transition, China objectively and historically sticks to the path of system innovation. This has significant theory value and strategic meaning for breaking down the lock-in and following the principle of path-dependence so as to realize the rapid development of economy.
基金supported by a grant from the National Natural Science Foundation of China(Nos.22274021,21974021 and 22036001)the Natural Science Foundation of Fujian Province(No.2022J01535)the Major Project of Science and Technology of Fujian Province(No.2020HZ06006)。
文摘Saccharides are a sort of ubiquitous and vital molecules within the whole life.However,the application of saccharides analysis with matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)is restricted by their low ionization efficiency and the instability of the sialic acid fraction.Derivatization strategy based on nonreductive amination provides a good solution,however,this is often time consuming and may result in sample loss due to removal of excessive derivatization reagents.Herein,hydralazine(HZN)was utilized as a reactive matrix for labeling reducing saccharides directly on MALDI target which eliminated tedious sample preparation and avoided sample loss.After optimization,effective and reproducible on-MALDI-target derivatization of neutral and acidic saccharides was achieved in both positive and negative modes.Compared with 2,5-dihydroxybenzoic acid(DHB)and 9-aminoacridine(9-AA),HZN improved the detection sensitivity of reducing saccharides and provided more abundant fragment ions in MS/MS analysis.Moreover,26 kinds of neutral glycans and 5 kinds of sialic glycans were identified from ovalbumin(OVA)and bovine fetuin,respectively.Combined with the statistical models,this strategy could be used to distinguish and predict samples of 6 brands of beer,and discriminate 2 kinds of beer fermentation modes.In addition,HZN was applied for quantitative analysis of glucose in urine samples,and the obtained urine glucose concentrations of diabetic patients were consistent with the clinical test results,showing the potential of qualitative and quantitative analysis of reducing saccharides in complex samples.
基金China Postdoctoral Science Foundation(2024M752424)National Natural Science Foundation of China(52305133,52232013).
文摘Superconducting electrodynamic suspension (EDS) presents numerous advantages, including large suspension gaps, high lift-to-drag ratios, and lower requirements for track irregularities. Recent advancements in superconducting materials have further enhanced the feasibility of this technology, and hence multiple research institutions are actively developing and improving this high-speed rail technology. Superconducting EDS achieves passive suspension and guidance by the interaction between ground null-flux coils and onboard superconducting magnets, forming an electromechanical coupled system. Thus, electromechanical coupling modeling and equivalent experimental methods are essential in evaluating and optimizing this system. This article reviews the research on dynamic characteristics analysis of superconducting EDS, focusing on modeling and experimental methods. Firstly, it revisits the development history of superconducting EDS and the new opportunities brought by advancements in superconducting materials. Secondly, it discusses various modeling approaches for the suspension system, emphasizing their benefits and limitations. Thirdly, it describes equivalent experimental methods and their respective application scenarios. Then, it reviews important conclusions and possible optimization methods related to dynamic performance and electromechanical coupling research. Additionally, the sliding window method is introduced to improve computational efficiency in vehicle dynamics modeling. This article provides insights into the current state and future directions of superconducting EDS research, serving as a valuable reference for researchers and engineers.
基金supported by the National Natural Science Foundation of China(Nos.21974021 and 22036001)the Major Project of Science and Technology of Fujian Province(No.2020HZ06006)。
文摘Cardiovascular disease(CVD)is a global health problem and is thought to be responsible for almost half of all deaths in the world.Nevertheless,currently available diagnostic methods for CVD are strongly depended on clinical observation and monitoring,which commonly result in false diagnosis.Herein,an attractive strategy of a metal-organic framework(MOF)nanofilm-based laser desorption/ionization mass spectrometry(LDI-MS)was developed for enhancing serum metabolic profiling,which could provide precise diagnosis and molecular subtyping of CVD.The porous MOF nanofilm fabricated on indium-tin oxide(ITO)glass possessed enhanced ionization efficiency and size-exclusion effect,which endowed it as substrate with high sensitivity and selectivity for serum metabolites.Furthermore,the MOF nanofilm with uniform surface and high orientation provided high-quality and high-reproducibility serum metabolic profiles(SMPs)without any tedious pretreatment.Further analysis of extracted serum metabolic fingerprints could successfully distinguish patients with CVD from healthy controls and also differentiate two major subtypes of CVD.This work not only extends the application of MOF nanofilm as an attractive MS probe,but also provide an alternative way for precise diagnosis of CVD in molecular level.
基金supported by the cross fusion project“Green Civil Engineering and Water Conservancy”(000-71202103D)Young and Middle-aged Project of Education Department of Fujian Province(JAT210784)Natural Science Foundation of Fujian province(2023J01133579).
文摘Irrigation has a significant impact on N_(x)O(N_(2)O and NO)emissions from cultivated land,yet the N_(2)O or NO emission among the irrigation lower limits under different irrigation modes has not been well compared.In an irrigated lettuce field,three DR(drip irrigation)lower limits were designed,including 75%(DR1),65%(DR2)and 55%(DR3)field capacity,and one FI(furrow irrigation)lower limit(65%field capacity).The N_(2)O and NO emission fluxes and soil nitrogen(N)forms were determined,and the linear correlation between these indicators was analyzed.Results showed that under the same irrigation regime,the N_(2)O and NO emissions from furrow irrigation treatment increased by 36.8%and 45.2%respectively compared to that from drip irrigation treatment.The cumulative N_(2)O and NO emissions under DR3 were 30.2%and 28.6%higher than under DR1,respectively.Moreover,DR1 was also the lowest among the four treatments in soil-N concentration.The N_(2)O and NO emission fluxes were more correlated to soil NH_(4)^(+)-N(r=0.88 and 0.76)or NO_(2)^(-)-N(r=0.90 and 0.80)concentration than soil-N and soluble organic N,indicating that N_(2)O and NO were mainly produced by the soil nitrification process.When the irrigation regime was the same,N_(2)O and NO emissions were lower with drip irrigation than with furrow irrigation.Besides,drip irrigation with small quota but high frequency reduced N_(2)O and NO emission compared to that with large quota but low frequency.
基金funded by the Major science and technology project of CNOOC(KJZX-2022-12-XNY-0803).
文摘Underground liquified natural gas(LNG)storage is essential in guaranteeing national energy strategic reserves,and its construction is being accelerated.The stability of surrounding rock of underground LNG storage caverns under stress-low temperature coupling effect is the key factor determining the feasibility of LNG storage.First,a mathematical model used for controlling the stress-low temperature coupling and the processes of rock damage evolution is given,followed by a 2-D numerical execution process of the mathematical model mentioned above described based on Comsol Multiphysics and Matlab code.Finally,a series of 2-D simulations are performed to study the influence of LNG storage cavern layout,burial depth,temperature and internal pressure on the stability of surrounding rocks of these underground storage caverns.The results indicate that all the factors mentioned above affect the evolution of deformation and plastic zone of surrounding rocks.The research results contribute to the engineering design of underground LNG storage caverns.