期刊文献+
共找到520篇文章
< 1 2 26 >
每页显示 20 50 100
Endorepellin downregulation promotes angiogenesis after experimental traumatic brain injury
1
作者 Qian Zhang Yao Jing +10 位作者 Qiuyuan Gong Lin Cai Ren Wang Dianxu Yang Liping Wang Meijie Qu hao chen Yaohui Tang Hengli Tian Jun Ding Zhiming Xu 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第5期1092-1097,共6页
Endorepellin plays a key role in the regulation of angiogenesis,but its effects on angiogenesis after traumatic brain injury are unclear.This study explored the effects of endorepellin on angiogenesis and neurobehavio... Endorepellin plays a key role in the regulation of angiogenesis,but its effects on angiogenesis after traumatic brain injury are unclear.This study explored the effects of endorepellin on angiogenesis and neurobehavioral outcomes after traumatic brain injury in mice.Mice were randomly divided into four groups:sham,controlled cortical impact only,adeno-associated virus(AAV)-green fluorescent protein,and AAV-shEndorepellin-green fluorescent protein groups.In the controlled cortical impact model,the transduction of AAV-shEndorepellin-green fluorescent protein downregulated endorepellin while increasing the number of CD31+/Ki-67+proliferating endothelial cells and the functional microvessel density in mouse brain.These changes resulted in improved neurological function compared with controlled cortical impact mice.Western blotting revealed increased expression of vascular endothelial growth factor and angiopoietin-1 in mice treated with AAV-shEndorepellin-green fluorescent protein.Synchrotron radiation angiography showed that endorepellin downregulation promoted angiogenesis and increased cortical neovascularization,which may further improve neurobehavioral outcomes.Furthermore,an in vitro study showed that downregulation of endorepellin increased tube formation by human umbilical vein endothelial cells compared with a control.Mechanistic analysis found that endorepellin downregulation may mediate angiogenesis by activating vascular endothelial growth factor-and angiopoietin-1-related signaling pathways. 展开更多
关键词 ANGIOGENESIS controlled cortical impact endorepellin neurological function traumatic brain injury
下载PDF
Integrated biomarker response to assess toxic impacts of iron and manganese on deep-sea mussel Gigantidas platifrons under a deep-sea mining activity scenario
2
作者 Li ZHOU Mengna LI +7 位作者 Zhaoshan ZHONG Minxiao WANG hao chen Chao LIAN hao WANG Huan ZHANG Lei CAO Chaolun LI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第2期522-532,共11页
Deep-sea mining activities can potentially release metals,which pose a toxicological threat to deep-sea ecosystems.Nevertheless,due to the remoteness and inaccessibility of the deep-sea biosphere,there is insufficient... Deep-sea mining activities can potentially release metals,which pose a toxicological threat to deep-sea ecosystems.Nevertheless,due to the remoteness and inaccessibility of the deep-sea biosphere,there is insufficient knowledge about the impact of metal exposure on its inhabitants.In this study,deep-sea mussel Gigantidas platifrons,a commonly used deep-sea toxicology model organism,was exposed to manganese(100,1000μg/L)or iron(500,5000μg/L)for 7 d,respectively.Manganese and iron were chosen for their high levels of occurrence within deep-sea deposits.Metal accumulation and a battery of biochemical biomarkers related to antioxidative stress in superoxide dismutase(SOD),catalase(CAT),malondialdehyde(MDA);immune function in alkaline phosphatase(AKP),acid phosphatase(ACP);and energy metabolism in pyruvate kinase(PK)and hexokinase(HK)were assessed in mussel gills.Results showed that deep-sea mussel G.platifrons exhibited a high capacity to accumulate Mn/Fe.In addition,most tested biochemical parameters were altered by metal exposure,demonstrating that metals could induce oxidative stress,suppress the immune system,and affect energy metabolism of deep-sea mussels.The integrated biomarker response(IBR)approach indicated that the exposure to Mn/Fe had a negative impact on deep-sea mussels,and Mn demonstrated a more harmful impact on deep-sea mussels than Fe.Additionally,SOD and CAT biomarkers had the greatest impact on IBR values in Mn treatments,while ACP and HK were most influential for the low-and high-dose Fe groups,respectively.This study represents the first application of the IBR approach to evaluate the toxicity of metals on deep-sea fauna and serves as a crucial framework for risk assessment of deep-sea mining-associated metal exposure. 展开更多
关键词 MUSSEL metal deep-sea mining BIOMARKER environmental monitoring
下载PDF
Enhancing thermodynamic stability of single-crystal Ni-rich cathode material via a synergistic dual-substitution strategy
3
作者 Jixue Shen Hui Li +6 位作者 haoyu Qi Zhan Lin Zeheng Li Chuanbo Zheng Weitong Du hao chen Shanqing Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期428-436,I0010,共10页
Nickel(Ni)-rich cathode materials have become promising candidates for the next-generation electrical vehicles due to their high specific capacity.However,the poor thermodynamic stability(including cyclic performance ... Nickel(Ni)-rich cathode materials have become promising candidates for the next-generation electrical vehicles due to their high specific capacity.However,the poor thermodynamic stability(including cyclic performance and safety performance or thermal stability)will restrain their wide commercial application.Herein,a single-crystal Ni-rich Li Ni_(0.83)Co_(0.12)Mn_(0.05)O_(2) cathode material is synthesized and modified by a dual-substitution strategy in which the high-valence doping element improves the structural stability by forming strong metal–oxygen binding forces,while the low-valence doping element eliminates high Li^(+)/Ni^(2+)mixing.As a result,this synergistic dual substitution can effectively suppress H2-H3 phase transition and generation of microcracks,thereby ultimately improving the thermodynamic stability of Ni-rich cathode material.Notably,the dual-doped Ni-rich cathode delivers an extremely high capacity retention of 81%after 250 cycles(vs.Li/Li+)in coin-type half cells and 87%after 1000 cycles(vs.graphite/Li^(+))in pouch-type full cells at a high temperature of 55℃.More impressively,the dual-doped sample exhibits excellent thermal stability,which demonstrates a higher thermal runaway temperature and a lower calorific value.The synergetic effects of this dual-substitution strategy pave a new pathway for addressing the critical challenges of Ni-rich cathode at high temperatures,which will significantly advance the high-energy-density and high-safety cathodes to the subsequent commercialization. 展开更多
关键词 Ni-rich cathode Single crystalline Dual-substitution strategy High-temperature cathode Li-ion batteries
下载PDF
ZnO Additive Boosts Charging Speed and Cycling Stability of Electrolytic Zn–Mn Batteries
4
作者 Jin Wu Yang Tang +6 位作者 haohang Xu Guandie Ma Jinhong Jiang Changpeng Xian Maowen Xu Shu‑Juan Bao hao chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第4期293-304,共12页
Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish... Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish deposition reaction kinetics of manganese oxide during the charge process and short cycle life. We show that, incorporating ZnO electrolyte additive can form a neutral and highly viscous gel-like electrolyte and render a new form of electrolytic Zn–Mn batteries with significantly improved charging capabilities. Specifically, the ZnO gel-like electrolyte activates the zinc sulfate hydroxide hydrate assisted Mn^(2+) deposition reaction and induces phase and structure change of the deposited manganese oxide(Zn_(2)Mn_(3)O_8·H_(2)O nanorods array), resulting in a significant enhancement of the charge capability and discharge efficiency. The charge capacity increases to 2.5 mAh cm^(-2) after 1 h constant-voltage charging at 2.0 V vs. Zn/Zn^(2+), and the capacity can retain for up to 2000 cycles with negligible attenuation. This research lays the foundation for the advancement of electrolytic Zn–Mn batteries with enhanced charging capability. 展开更多
关键词 Electrolytic aqueous zinc-manganese batteries Electrolyte pH value ZnO electrolyte additive Fast constant-voltage charging ability
下载PDF
Distributed Economic MPC for Synergetic Regulation of the Voltage of an Island DC Micro-Grid
5
作者 Yi Zheng Yanye Wang +2 位作者 Xun Meng Shaoyuan Li hao chen 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期734-745,共12页
In this paper,distributed model predictive control(DMPC) for island DC micro-grids(MG) with wind/photovoltaic(PV)/battery power is proposed,which coordinates all distributed generations(DG) to stabilize the bus voltag... In this paper,distributed model predictive control(DMPC) for island DC micro-grids(MG) with wind/photovoltaic(PV)/battery power is proposed,which coordinates all distributed generations(DG) to stabilize the bus voltage together with the insurance of having computational efficiency under a real-time requirement.Based on the feedback of the bus voltage,the deviation of the current is dispatched to each DG according to cost over the prediction horizon.Moreover,to avoid the excessive fluctuation of the battery power,both the discharge-charge switching times and costs are considered in the model predictive control(MPC) optimization problems.A Lyapunov constraint with a time-varying steady-state is designed in each local MPC to guarantee the stabilization of the entire system.The voltage stabilization of the MG is achieved by this strategy with the cooperation of DGs.The numeric results of applying the proposed method to a MG of the Shanghai Power Supply Company shows the effectiveness of the distributed economic MPC. 展开更多
关键词 Distributed model predictive control(DMPC) Lyapunovbased model predictive control micro-grid(MG) voltage control
下载PDF
Additive manufactured osseointegrated screws with hierarchical design
6
作者 Wenbo Yang hao chen +6 位作者 haotian Bai Yifu Sun Aobo Zhang Yang Liu Yuchao Song Qing Han Jincheng Wang 《Bio-Design and Manufacturing》 SCIE EI CAS CSCD 2024年第2期206-235,共30页
Bone screws are devices used to fix implants or bones to bones.However,conventional screws are mechanically fixed with thread and often face long-term failure due to poor osseointegration.To improve osseointegration,s... Bone screws are devices used to fix implants or bones to bones.However,conventional screws are mechanically fixed with thread and often face long-term failure due to poor osseointegration.To improve osseointegration,screws are evolving from solid and smooth to porous and rough.Additive manufacturing(AM)offers a high degree of manufacturing freedom,enabling the preparation of predesigned screws that are porous and rough.This paper provides an overview of the problems currently faced by bone screws:long-term loosening and screw breakage.Next,advances in osseointegrated screws are summarized hierarchically(sub-micro,micro,and macro).At the sub-microscale level,we describe surface-modification techniques for enhancing osseointegration.At the micro level,we summarize the micro-design parameters that affect the mechanical and biological properties of porous osseointegrated screws,including porosity,pore size,and pore shape.In addition,we highlight three promising pore shapes:triply periodic minimal surface,auxetic structure with negative Poisson ratio,and the Voronoi structure.At the macro level,we outline the strategies of graded design,gradient design,and topology optimization design to improve the mechanical strength of porous osseointegrated screws.Simultaneously,this paper outlines advances in AM technology for enhancing the mechanical properties of porous osseointegrated screws.AM osseointegrated screws with hierarchical design are expected to provide excellent long-term fixation and the required mechanical strength. 展开更多
关键词 Bone screws Additive manufacturing Architecture design Surface modification
下载PDF
Mechanistic research:Selenium regulates virulence factors,reducing adhesion ability and inflammatory damage of Helicobacter pylori
7
作者 Chun Qin Gan-Rong Huang +6 位作者 Ai-Xing Guan Wen-Ting Zhou hao chen Pei-Pei Luo Xian-Ke Luo Yan-Qiang Huang Zan-Song Huang 《World Journal of Gastroenterology》 SCIE CAS 2024年第1期91-107,共17页
BACKGROUND The pathogenicity of Helicobacter pylori is dependent on factors including the environment and the host.Although selenium is closely related to pathogenicity as an environmental factor,the specific correlat... BACKGROUND The pathogenicity of Helicobacter pylori is dependent on factors including the environment and the host.Although selenium is closely related to pathogenicity as an environmental factor,the specific correlation between them remains unclear.AIM To investigate how selenium acts on virulence factors and reduces their toxicity.METHODS H.pylori strains were induced by sodium selenite.The expression of cytotoxin-associated protein A(CagA)and vacuolating cytotoxin gene A(VacA)was determined by quantitative PCR and Western blotting.Transcriptomics was used to analyze CagA,CagM,CagE,Cag1,Cag3,and CagT.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction,and H.pylori colonization,inflammatory reactions,and the cell adhesion ability of H.pylori were assessed.RESULTS CagA and VacA expression was upregulated at first and then downregulated in the H.pylori strains after sodium selenite treatment.Their expression was significantly and steadily downregulated after the 5th cycle(10 d).Transcriptome analysis revealed that sodium selenite altered the levels affect H.pylori virulence factors such as CagA,CagM,CagE,Cag1,Cag3,and CagT.Of these factors,CagM and CagE expression was continuously downregulated and further downregulated after 2 h of induction with sodium selenite.Moreover,CagT expression was upregulated before the 3rd cycle(6 d)and significantly downregulated after the 5th cycle.Cag1 and Cag3 expression was upregulated and downregulated,respectively,but no significant change was observed by the 5th cycle.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction.The extent of H.pylori colonization in the stomach increased;however,sodium selenite also induced a mild inflammatory reaction in the gastric mucosa of H.pylori-infected mice,and the cell adhesion ability of H.pylori was significantly weakened.CONCLUSION These results demonstrate that H.pylori displayed virulence attenuation after the 10th d of sodium selenite treatment.Sodium selenite is a low toxicity compound with strong stability that can reduce the cell adhesion ability of H.pylori,thus mitigating the inflammatory damage to the gastric mucosa. 展开更多
关键词 Helicobacter pylori Sodium selenite Virulence factors ADHERENCE Inflammation
下载PDF
Numerical Analysis of the Influence of the Impinging Distance on the Scouring Efficiency of Submerged Jets
8
作者 hao chen Xianbin Teng +3 位作者 Zhibin Zhang Faxin Zhu Jie Wang Zhaohao Zhang 《Fluid Dynamics & Materials Processing》 EI 2024年第2期429-445,共17页
Water jet technology is widely used in submerged buried pipes as a non-traditional trenching process,often invol-ving a complex sediment response.An important adjustable and influential engineering variable in this tec... Water jet technology is widely used in submerged buried pipes as a non-traditional trenching process,often invol-ving a complex sediment response.An important adjustable and influential engineering variable in this technol-ogy is represented by the impinging distance.In this study,the FLOW-3D software was used to simulate the jet scouring of sand beds in a submerged environment.In particular,four sets of experimental conditions were con-sidered to discern the relationship between the maximum scour depth and mass and the impinging distance.As shown by the results,a critical impinging distance h0 exists by which the static scour depth can be maximized;the scour mass ratio between dynamic and static conditions decreases as the impinging distance increases.Moreover,the profile contours are similar when the erosion parameter Ec is in the range 0.35<Ec<2.Empirical equations applicable for predicting the jet trenching contour under both dynamic and static scour modes are also provided in this study. 展开更多
关键词 Submerged jet impinging distance numerical simulation scour depth scour profile
下载PDF
Changes in macrophage infiltration and podocyte injury in lupus nephritis patients with repeated renal biopsy: Report of three cases
9
作者 Shi-Yuan Liu hao chen +8 位作者 Li-Jia He Chun-Kai Huang Pu Wang Zhang-Ru Rui Jue Wu Yang Yuan Yue Zhang Wen-Ju Wang Xiao-Dan Wang 《World Journal of Clinical Cases》 SCIE 2024年第1期188-195,共8页
BACKGROUND In this study,we retrospectively analysed macrophage infiltration and podocyte injury in three patients with diffuse proliferative lupus nephritis(LN)who un-derwent repeated renal biopsy.CASE SUMMARY Clinic... BACKGROUND In this study,we retrospectively analysed macrophage infiltration and podocyte injury in three patients with diffuse proliferative lupus nephritis(LN)who un-derwent repeated renal biopsy.CASE SUMMARY Clinical data of three diffuse proliferative LN patients with different pathological characteristics(case 1 was LN IV-G(A),case 2 was LN IV-G(A)+V,and case 3 was LN IV-G(A)+thrombotic microangiopathy)were reviewed.All patients underwent repeated renal biopsies 6 mo later,and renal biopsy specimens were studied.Macrophage infiltration was assessed by CD68 expression detected by immunohistochemical staining,and an immunofluorescence assay was used to detect podocin expression to assess podocyte damage.After treatment,Case 1 changed to LN III-(A),Case 2 remained as type V LN lesions,and Case 3,which changed to LN IV-S(A),had the worst prognosis.We observed reduced macro-phage infiltration after therapy.However,two of the patients with active lesions after treatment still showed macrophage infiltration in the renal interstitium.Before treatment,the three patients showed discontinuous expression of podocin.Notably,the integrity of podocin was restored after treatment in Case 1.CONCLUSION It may be possible to reverse podocyte damage and decrease the infiltrating ma-crophages in LN patients through effective treatment. 展开更多
关键词 Lupus nephritis MACROPHAGE PODOCYTE Repeat renal biopsy Thrombotic microangiopathy Case report
下载PDF
The Combination of Achnatherum inebrians Extracts and Soil Microorganisms Inhibited Seed Germination and Seedling Growth in Elymus nutans
10
作者 Rui Zhang Taixiang chen +4 位作者 Zhenjiang chen hao chen Xuekai Wei Malik Kamran Chunjie Li 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第3期567-580,共14页
In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts f... In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts from aboveground and belowground parts of A.inebrians significantly inhibited the germination rate,germination potential,germination index,vigor index,seedling height,root length,and fresh weight of E.nutans,but increased malondialdehyde content,catalase,peroxidase and superoxide dismutase activity of E.nutans seedlings(p<0.05).The allelopathy of aqueous extracts of the aboveground parts of A.inebrians was stronger than that of the pre-cipitates.Aqueous extracts of the aboveground parts of A.inebrians decreased seed germination rate,germination potential,germination index,vigor index,seedling length,root length,and seedling fresh weight by 10.45%-74.63%,24.18%-32.50%,19.03%-73.36%,37.83%-88.41%,21.42%-53.14%,2.65%-40.21%,and 20.45%-61.36%,respectively,and malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity increased by 8.09%-62.24%,27.83%-86.47%,22.90%-93.17%,and 11.15%-75.91%,respectively.The above indexes were higher in live soil than in sterilized soil.Soil microorganisms increased the allelopathy of A.inebrians.The seed germination rate,germination potential,germination index,vigor index,seedling length,and seedling fresh weight of E.nutans planted in live soil decreased by 8.22%-48.48%,10.00%-51.85%,8.19%-53.26%,16.43%-60.03%,12.91%-28.81%,and 9.09%-22.86%compared with sterilized soil,respectively.Malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity of E.nutans planted in live soil increased by 53.91%-81.06%,15.71%-57.34%,33.33%-86.31%,and 9.78%-52.51%compared with sterilized soil,respectively.The existence of soil microorganisms enhanced the allelopathy of the secondary metabolites of A.inebrians.A combination of microorganisms and aqueous extracts from the aboveground parts of A.inebrians had the strongest allelopathic effect on E.nutans. 展开更多
关键词 Achnatherum inebrians water immersion liquid aqueous leachate precipitate ALLELOPATHY Elymus nutans soil microorganisms
下载PDF
Study on sex differences and potential clinical value of threedimensional computerized tomography pelvimetry in rectal cancer patients
11
作者 Xiao-Cong Zhou Fei-Yue Ke +2 位作者 Gaurav Dhamija hao chen Qiang Wang 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第3期773-786,共14页
BACKGROUND Laparoscopic rectal cancer radical surgery is a complex procedure affected by various factors.However,the existing literature lacks standardized parameters for the pelvic region and soft tissues,which hampe... BACKGROUND Laparoscopic rectal cancer radical surgery is a complex procedure affected by various factors.However,the existing literature lacks standardized parameters for the pelvic region and soft tissues,which hampers the establishment of consistent conclusions.AIM To comprehensively assess 16 pelvic and 7 soft tissue parameters through computerized tomography(CT)-based three-dimensional(3D)reconstruction,providing a strong theoretical basis to address challenges in laparoscopic rectal cancer radical surgery.METHODS We analyzed data from 218 patients who underwent radical laparoscopic surgery for rectal cancer,and utilized CT data for 3D pelvic reconstruction.Specific anatomical points were carefully marked and measured using advanced 3D modeling software.To analyze the pelvic and soft tissue parameters,we emp-loyed statistical methods including paired sample t-tests,Wilcoxon rank-sum tests,and correlation analysis.RESULTS The investigation highlighted significant sex disparities in 14 pelvic bone parameters and 3 soft tissue parameters.Males demonstrated larger measurements in pelvic depth and overall curvature,smaller measurements in pelvic width,a larger mesorectal fat area,and a larger anterior-posterior abdominal diameter.By contrast,females exhibited wider pelvises,shallower depth,smaller overall curvature,and an increased amount of subcutaneous fat tissue.However,there were no significant sex differences observed in certain parameters such as sacral curvature height,superior pubococcygeal diameter,rectal area,visceral fat area,waist circumference,and transverse abdominal diameter.CONCLUSION The reconstruction of 3D CT data enabled accurate pelvic measurements,revealing significant sex differences in both pelvic and soft tissue parameters.This study design offer potential in predicting surgical difficulties and creating personalized surgical plans for male rectal cancer patients with a potentially“difficult pelvis”,ultimately improving surgical outcomes.Further research and utilization of these parameters could lead to enhanced surgical methods and patient care in laparoscopic rectal cancer radical surgery. 展开更多
关键词 Computerized tomography Rectal cancer Three-dimensional reconstruction PELVIMETRY Sex differences
下载PDF
Enhanced reversible hydrogen storage properties of wrinkled graphene microflowers confined LiBH_(4) system with high volumetric hydrogen storage capacity
12
作者 Zhenglong Li Kaicheng Xian +9 位作者 hao chen Mingxia Gao Shanqing Qu Meihong Wu Yaxiong Yang Wenping Sun Chao Gao Yongfeng Liu Xin Zhang Hongge Pan 《Materials Reports(Energy)》 EI 2024年第1期79-88,共10页
LiBH_(4)with high hydrogen storage density,is regarded as one of the most promising hydrogen storage materials.Nevertheless,it suffers from high dehydrogenation temperature and poor reversibility for practical use.Nan... LiBH_(4)with high hydrogen storage density,is regarded as one of the most promising hydrogen storage materials.Nevertheless,it suffers from high dehydrogenation temperature and poor reversibility for practical use.Nanoconfinement is effective in achieving low dehydrogenation temperature and favorable reversibility.Besides,graphene can serve as supporting materials for LiBH_(4)catalysts and also destabilize LiBH_(4)via interfacial reaction.However,graphene has never been used alone as a frame material for nanoconfining LiBH_(4).In this study,graphene microflowers with large pore volumes were prepared and used as nanoconfinement framework material for LiBH_(4),and the nanoconfinement effect of graphene was revealed.After loading 70 wt%of LiBH_(4) and mechanically compressed at 350 MPa,8.0 wt% of H2 can be released within 100 min at 320C,corresponding to the highest volumetric hydrogen storage density of 94.9 g H2 L^(-1)ever reported.Thanks to the nanoconfinement of graphene,the rate-limiting step of dehydrogenation of nanoconfined LiBH_(4) was changed and its apparent activation energy of the dehydrogenation(107.3 kJ mol^(-1))was 42%lower than that of pure LiBH_(4).Moreover,the formation of the intermediate Li_(2)B_(12)H_(12) was effectively inhibited,and the stable nanoconfined structure enhanced the reversibility of LiBH_(4).This work widens the understanding of graphene's nanoconfinement effect and provides new insights for developing high-density hydrogen storage materials. 展开更多
关键词 Hydrogen storage LiBH_(4) NANOCONFINEMENT GRAPHENE High capacity
下载PDF
密闭空间下放射性核素扩散研究及自主程序开发
13
作者 李昂 汪镇澜 +1 位作者 郝琛 董峙豪 《火箭军工程大学学报》 2024年第1期1-11,共11页
为了评估安全壳完整时发生一回路破口事故后,放射性核素在封闭空间中扩散时的个人受照剂量,对放射性核素扩散迁移过程开展模拟计算。采用隔室模型对密闭空间进行物理建模,使用多参数一阶动力学微分方程描述放射性核素在密闭空间内的迁... 为了评估安全壳完整时发生一回路破口事故后,放射性核素在封闭空间中扩散时的个人受照剂量,对放射性核素扩散迁移过程开展模拟计算。采用隔室模型对密闭空间进行物理建模,使用多参数一阶动力学微分方程描述放射性核素在密闭空间内的迁移过程,自主开发了放射性核素扩散计算程序DMRC(Diffusion and Migration of Radi-onuclide Code)。采用DMRC程序计算了TACT(Transport of ACTivity)基准题中的放射性核素活度和假想个人剂量,计算结果与基准解结果符合良好。最后,对某真实核电厂一回路破口事故进行模拟,计算了事故发生后30天内安全壳和外部环境的放射性活度以及假想个人剂量。结果显示:该事故发生后公众接受的最大有效剂量及最大甲状腺当量剂量均小于国家规定限值。结果表明:本文工作可以用于事故工况下的环境安全分析和人员健康评估。 展开更多
关键词 破口事故 放射性核素扩散迁移 DMRC 假想个人剂量
原文传递
Analysis and Prediction Model Reinforced UHPC Shrinkage Property
14
作者 Shuwen Deng Zhiming Huang +1 位作者 hao chen Jia Hu 《Journal of Architectural Research and Development》 2024年第2期99-107,共9页
This paper explores the shrinkage of reinforced UHPC under high-temperature steam curing and natural curing conditions.The results are compared with the existing shrinkage prediction models.The results show that the m... This paper explores the shrinkage of reinforced UHPC under high-temperature steam curing and natural curing conditions.The results are compared with the existing shrinkage prediction models.The results show that the maximum shrinkage strain of reinforced UHPC after steam curing is 164μεand gradually becomes zero.As for natural curing,the maximum shrinkage strain is 173μεand the value stabilizes on the 10th day after pouring.This indicated that steam curing can significantly reduce shrinkage time.Compared with the plain UHPC tested in the previous literature,the structural reinforcement can significantly inhibit the UHPC shrinkage and greatly reduce the risk of cracking due to shrinkage.By comparing the results in this paper with the existing models for predicting the shrinkage strain development,it is found that the formula recommended in the French UHPC structural and technical specification is suitable for the shrinkage curve in the present paper. 展开更多
关键词 Ultra-high performance concrete(UHPC) UHPC shrinkage Reinforced UHPC slab Shrinkage prediction
下载PDF
金代家风特征、成因及影响探析
15
作者 郝辰 《中华家教》 2024年第1期87-94,共8页
金代作为中国历史上重要的北方少数民族政权,是女真族、契丹族、汉族等多民族融合的朝代。金人在整体性的政治社会环境影响下,十分重视并形成了特有的家风传统。根据对相关石刻资料和文献资料的挖掘、辨析和梳理,可探究出金人的家风传... 金代作为中国历史上重要的北方少数民族政权,是女真族、契丹族、汉族等多民族融合的朝代。金人在整体性的政治社会环境影响下,十分重视并形成了特有的家风传统。根据对相关石刻资料和文献资料的挖掘、辨析和梳理,可探究出金人的家风传统主要体现在勤俭持家、孝悌忠信、崇儒入仕、尚武爱国、丰财与尚医等方面。同时,金人承担家庭教育的主体是父母,其他族中长辈也参与其中,如通过日常教导、遗言遗训等途径。金人家风对个体家族的发展延绵和社会的整体风气塑造有重要作用,同时也能为当前家庭教育提供一定启示。 展开更多
关键词 金代 家风 家教
下载PDF
基于NiZn层状双金属氢氧化物制备高效电催化CO_(2)还原的原子分散Ni-N-C催化剂
16
作者 张平 陈浩 +7 位作者 陈林 熊鹰 孙子其 杨浩宇 付莹珂 张亚萍 廖婷 李斐 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第2期152-161,共10页
大气中CO_(2)浓度不断上升导致大量的环境问题,如冰川融化、温室效应、极端天气等,利用电化学方法将CO_(2)经还原反应(CO_(2)RR)转化为有价值的燃料或化学品是解决该问题的可行策略.由于CO_(2)具有稳定的化学键(C=O,806 kJ mol^(-1)),... 大气中CO_(2)浓度不断上升导致大量的环境问题,如冰川融化、温室效应、极端天气等,利用电化学方法将CO_(2)经还原反应(CO_(2)RR)转化为有价值的燃料或化学品是解决该问题的可行策略.由于CO_(2)具有稳定的化学键(C=O,806 kJ mol^(-1)),需设计具有优异活性和高选择性的催化剂.近年研究结果表明,过渡金属锚定在N掺杂碳载体上而制得的催化剂(M-N-C)具有较高的原子利用率、独特的活性金属中心电子结构以及存储量丰富,因而被认为是CO_(2)还原为CO的理想电催化剂.目前已经提出了多种方法来制备M-N-C催化剂,包括原子层沉积、基于金属-有机骨架的离子交换、基于载体修饰策略的吸附固化和受限热解.然而,这些方法存在制备过程繁琐或难以大规模生产的问题.同时,采用高温热解制备的M-N-C催化剂,金属活性位点易被其致密的结构包裹,难以完全暴露出来.但有效的活性位点对M-N-C的催化性能起着至关重要的作用,因此有必要研制一种简便、高效的方法来抑制金属原子聚集.超薄二维碳骨架已被证明可以缩短反应物的扩散路径并有利于暴露催化剂活性位点.本文将NiZn层状双金属氢氧化物(NiZn-LDHs)在多羟基化合物中进行剥离形成单层,同时通过控制单层NiZn-LDHs、多羟基化合物和三聚氰胺共同热解,宏量化制得Ni-N-C催化剂.X射线衍射(XRD)和透射电子显微镜(TEM)结果表明,在焙烧过程中,可通过改变单层NiZn-LDHs在多羟基化合物中的含量控制Ni-N-C材料中镍纳米颗粒的生成;焙烧过程中Zn挥发能使Ni-N-C材料形成更多中孔,增加碳骨架比表面积和孔径.中孔通道和碳基底超薄特性结合可以促进CO_(2)向内部活性位点扩散,增加反应物与活性位点的接触.XPS结果表明,Ni-N-C材料中Ni原子通过与N配位,锚定在超薄碳骨架上,且存在Niδ+中心(0<δ<2).X射线近边吸收和扩展X射线吸收精细结构分析表明,Ni-N-C-1中的Ni处于低价态(0<δ<2),这与XPS分析一致,且Ni为原子级分散;小波变换分析表明,Ni和N的配位数为3.9.利用H型电解池评估Ni-N-C材料电催化CO_(2)还原性能表明,Ni-N-C-1具有优异的CO_(2)还原活性,在-0.6至-1.0 V电位范围内,FE_(CO)都大于90%,且在-4.9 V时,FE_(CO)为95.2%,CO电流密度为24 mA cm^(-2);在-0.8 V电位,工作25 h后Ni-N-C-1的CO电流密度基本保持不变,说明Ni-N-C-1为稳定的CO_(2)RR催化剂.通过密度泛函理论计算研究了Ni-N-C材料电催化CO_(2)还原为CO的电化学演化历程,结果表明,该反应过程分四个步骤:CO_(2)吸附到单个Ni原子位点上;转移形成*COOH的质子/电子对;*COOH在释放H_(2)O的同时获得质子形成*CO;*CO从Ni位点解吸.相应步骤的吉布斯自由能分别为0.54,1.69,-0.99和-0.98 eV.Ni-N-C中Ni原子与配位N原子之间的强相互作用导致Ni原子的电子损失,Ni原子有0.85 e缺陷,周围的N原子有0.15 e堆积,这有利于CO_(2)的吸附.总之,本文采用单层NiZn-LDHs为金属源,开发了一种简便且可宏量化制备CO_(2)RR单原子催化剂的新方法. 展开更多
关键词 NiZn层状双金属氢氧化物 CO_(2)还原 Ni-N-C催化剂 活性位点 高效制备
下载PDF
思维能力导向的线上物理化学实验课程建设与应用
17
作者 闫华 吴俊勇 +4 位作者 吴树昌 陈浩 陈章新 钟爱国 金燕仙 《大学化学》 CAS 2023年第9期39-46,共8页
为了解决物理化学实验课程学习难度大与课堂教学时间少的矛盾,弥补传统的物理化学实验教学“重过程、轻结果”的缺点,建设了线上物理化学实验课程。线上物理化学实验课程通过实验原理和仪器操作视频、实验习题、问题讨论等模块,完成知... 为了解决物理化学实验课程学习难度大与课堂教学时间少的矛盾,弥补传统的物理化学实验教学“重过程、轻结果”的缺点,建设了线上物理化学实验课程。线上物理化学实验课程通过实验原理和仪器操作视频、实验习题、问题讨论等模块,完成知识、技能和思维能力的培养,与线下实验操作训练形成良好的互补关系。线上物理化学实验课程为翻转传统的物理化学实验课堂提供了前提条件,明显提高了教学效果。 展开更多
关键词 物理化学实验 线上 翻转课堂 一流课程
下载PDF
数字经济发展对旅游业全要素生产率的非线性效应 被引量:20
18
作者 吴丹丹 冯学钢 +2 位作者 马仁锋 郝晨 吴杨 《旅游学刊》 北大核心 2023年第2期47-65,共19页
数字经济作为新型产业驱动力,已成为促进区域旅游业转型升级的关键因素。但基于城市尺度,数字经济与旅游业全要素生产率间的关系在学术上仍未得到系统性实证。文章融合多源数据构建数字经济发展水平指数,运用全局可参比Malmquist模型测... 数字经济作为新型产业驱动力,已成为促进区域旅游业转型升级的关键因素。但基于城市尺度,数字经济与旅游业全要素生产率间的关系在学术上仍未得到系统性实证。文章融合多源数据构建数字经济发展水平指数,运用全局可参比Malmquist模型测算2011—2019年中国285个地级及以上城市旅游业全要素生产率,继而采用面板平滑转换回归模型探索性实证数字经济与旅游业全要素生产率之间的平滑转换效应。结果表明:(1)数字经济发展能够显著提高旅游业全要素生产率,而且旅游业技术进步是数字经济促进城市旅游业全要素生产率提升的重要途径。(2)数字经济对旅游业全要素生产率的影响呈现边际效应递增的非线性平滑转换特征。经过稳健性和内生性检验,其影响效果保持稳健。(3)数字基础设施、数字产业发展、数字创新潜力和数字普惠金融等分维度对旅游业全要素生产率和技术进步同样具有显著的非线性促进效应。(4)分地区异质性分析显示,在高旅游业发展地区和高数字经济发展地区,数字经济对旅游业全要素生产率的促进作用更为明显。上述结论不仅为理解和分析中国城市旅游业全要素生产率发展提供了新的视角,也为合理利用数字经济促进城市旅游业高质量发展提供了参考。未来,政策上应推动“数字经济+旅游”深度融合、完善互联网营销体系,加强数字经济时代的旅游业制度创新,同时高度关注数字经济影响效应的异质性特征,促进不同类型城市旅游业全要素生产率协调发展。 展开更多
关键词 数字经济 技术效率 旅游业全要素生产率 全局可参比Malmquist模型 面板平滑转换回归模型
下载PDF
中国式保险治理现代化进程研究——基于1979—2022年的1000部法律法规文件
19
作者 郝臣 董迎秋 +2 位作者 马贵军 曹嘉宁 冯子朔 《保险职业学院学报》 2023年第3期21-31,共11页
法律法规是治理制度安排的基础,保险治理法律法规的建设状况能够科学地刻画中国式保险治理现代化的进程。本文在界定保险治理、保险业治理、保险机构治理和保险公司治理内涵的基础上,手工整理了我国1979年保险业复业至2022年年末总计44... 法律法规是治理制度安排的基础,保险治理法律法规的建设状况能够科学地刻画中国式保险治理现代化的进程。本文在界定保险治理、保险业治理、保险机构治理和保险公司治理内涵的基础上,手工整理了我国1979年保险业复业至2022年年末总计44年期间各类主体出台的1000部保险治理法律法规文件,并基于整理的文件进行了总体分析和具体分析。在总体分析中,本文详细梳理了我国保险治理法律法规的发展脉络,划分了我国保险治理的发展阶段,并从发布主体、修改次数和有效性等方面进行了统计分析;在具体分析中,本文根据治理内容不同,将保险治理法律法规文件细分至多个层级。最后,本文提出了中国式保险治理现代化进程的六点结论和四点展望。 展开更多
关键词 保险治理 中国式现代化 法律法规
下载PDF
空气过滤用驻极体纤维材料研究进展 被引量:1
20
作者 高涵超 张苏广 +8 位作者 夏兆鹏 段书霞 付迎坤 韩修恒 赵义侠 陈浩 史清源 王亮 刘雍 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2023年第4期173-181,共9页
驻极体纤维过滤材料是口罩、空气净化器、暖通空调系统过滤器等空气过滤产品的核心滤层材料,驻极纤维滤材可利用纤维与气溶胶颗粒间的静电力捕集气溶胶颗粒,表现出高效低阻过滤性能。文中介绍了驻极过滤材料的静电吸附机理、电荷表征方... 驻极体纤维过滤材料是口罩、空气净化器、暖通空调系统过滤器等空气过滤产品的核心滤层材料,驻极纤维滤材可利用纤维与气溶胶颗粒间的静电力捕集气溶胶颗粒,表现出高效低阻过滤性能。文中介绍了驻极过滤材料的静电吸附机理、电荷表征方法,分析了驻极原料、驻极工艺和存放环境等影响驻极过滤材料电荷稳定性的因素,从构建复合膜结构、添加纳米颗粒两方面阐述了提升驻极材料带电能力和电荷稳定性的研究现状,最后提出了驻极体纤维过滤材料目前存在的问题及未来发展方向。 展开更多
关键词 驻极体 纤维滤材 驻极技术 电荷稳定性 空气过滤性能
下载PDF
上一页 1 2 26 下一页 到第
使用帮助 返回顶部