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聚合物三腔微管挤出口模结构对胀大变形的影响
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作者 刘磊 李经纬 +3 位作者 王鑫杨 刘奎 杨天洋 赵丹阳 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2024年第1期82-91,共10页
聚合物熔体的模内流动状态与模外胀大变形直接影响微挤出制品的成型质量。文中基于Carreau模型,采用数值模拟方法,研究了聚合物三腔微管挤出过程中口模壁厚差与空心度结构特征对胀大变形行为的影响。结果表明,影响挤出胀大变形程度的关... 聚合物熔体的模内流动状态与模外胀大变形直接影响微挤出制品的成型质量。文中基于Carreau模型,采用数值模拟方法,研究了聚合物三腔微管挤出过程中口模壁厚差与空心度结构特征对胀大变形行为的影响。结果表明,影响挤出胀大变形程度的关键因素是口模出口附近的轴向速度分布;内外壁厚差会导致较大壁厚位置处对应的型坯厚度增大,而较小壁厚位置处的型坯厚度减小,壁厚差变化对薄壁区域壁厚变形影响较大,达到91.4%;空心度减小能提升口模出口附近轴向速度分布均匀性,减小了70.1%的变形程度;基于胀大变形规律逆向补偿设计了口模形状与尺寸,明显改善了制品成型质量。研究结果对聚合物多腔微管的口模结构优化设计具有理论意义与工程应用价值。 展开更多
关键词 挤出口模结构 胀大变形 壁厚差 异型多腔微管 逆向补偿设计
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Enhancing pain modulation: the efficacy of synchronous combination of virtual reality and transcutaneous electrical nerve stimulation
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作者 Yanzhi Bi Xu liu +5 位作者 Xiangyue Zhao Shiyu Wei jingwei li Faguang Wang Wenbo Luo li Hu 《General Psychiatry》 CSCD 2023年第6期501-511,共11页
Introduction Virtual reality(VR)and transcutaneous electrical nerve stimulation(TENS)have emerged as effective interventions for pain reduction.However,their standalone applications often yield limited analgesic effec... Introduction Virtual reality(VR)and transcutaneous electrical nerve stimulation(TENS)have emerged as effective interventions for pain reduction.However,their standalone applications often yield limited analgesic effects,particularly in certain painful conditions.Aims Our hypothesis was that the combination of VR with TENS in a synchronous manner could produce the best analgesic effect among the four experimental conditions.Methods To address this challenge,we proposed a novel pain modulation strategy that synchronously combines VR and TENS,aiming to capitalise on both techniques'complementary pain modulation mechanisms.Thirty-two healthy subjects participated in the study and underwent three types of interventions:VR alone,a combination of VR with conventional TENS,and a combination of VR with synchronous TENS.Additionally,a control condition with no intervention was included.Perceived pain intensity,pain unpleasantness,positive and negativeaffect scores,and electroencephalographic(EEG)data were collected before and after the interventions.To delve into the potential moderating role of pain intensity on the analgesic efficacy of VR combined with synchronous TENS,we incorporated two distinct levels of painful stimuli:one representing mild to moderate pain(ie,low pain)and the other representing moderate to severe pain(ie,high pain).Results Our findings revealed that both combination interventions exhibited superior analgesic effects compared with the VR-alone intervention when exposed to low and high pain stimuli.Notably,the combination of VR with synchronous TENS demonstrated greater analgesic efficacy than the combination of VR with conventional TENS.EEG data further supported these results,indicating that both combination interventions elicited a greater reduction in event-related potential magnitude compared with the VR-alone intervention during exposure to low and high pain stimuli.Moreover,the synchronous combination intervention induced a more significant reduction in N2 amplitude than the VR-alone intervention during exposure to low pain stimuli.No significant differences in EEG response changes were detected between the two combination interventions.Both combination interventions resulted in a greater reduction in negative affect compared with the VR-alone intervention.Conclusions Altogether,our study highlights the effectiveness of the synchronous combination of VR and TENS in enhancing pain modulation.These findings offer valuable insights for developing innovative pain treatments,emphasising the importance of tailored and multifaceted therapeutic approaches for various painful conditions. 展开更多
关键词 PAIN STIMULATION ALONE
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用于丁二烯选择性加氢Ni_(3)ZnC_(0.7)@Ni@C催化剂的设计
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作者 陈智冰 陈鑫泰 +6 位作者 吕雅丽 牟效玲 范佳辉 李经伟 严丽 林荣和 丁云杰 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第5期304-315,共12页
丁二烯选择性加氢是提升碳四综合利用效率的关键技术,因此受到了工业界和学术界的广泛关注.然而,在实际操作过程中,原料中的单烯烃也可能发生加氢,这降低了整个工艺过程的经济性.此外,丁二烯分子内含有两个共轭的C=C双键,其化学性质活泼... 丁二烯选择性加氢是提升碳四综合利用效率的关键技术,因此受到了工业界和学术界的广泛关注.然而,在实际操作过程中,原料中的单烯烃也可能发生加氢,这降低了整个工艺过程的经济性.此外,丁二烯分子内含有两个共轭的C=C双键,其化学性质活泼,容易在金属催化剂表面发生聚合生成碳沉积物,从而导致催化剂失活.因此,如何提高烯烃的选择性和催化剂的稳定性成为一项挑战.目前,丁二烯加氢反应主要采用Pd,Pt,Au等贵金属催化剂,但贵金属的高昂价格和稀缺性限制了其大规模应用.因此,开发基于廉价金属的替代催化剂具有重要意义.镍基体系在丁二烯的选择性加氢中显示出一定潜力,然而,其实际应用受到积炭和过度加氢导致的严重失活等问题的影响.本文在前期工作固相法合成Ni_(3)ZnC_(0.7)@C(采用无溶剂的固态反应法合成,将金属硝酸盐与双氰胺机械混合,再于氢气下高温还原制得,其中Ni_(3)ZnC_(0.7)颗粒外围具有碳层覆盖,详见Dalton Trans.,2023,52,11571–11580)基础上,通过对Ni_(3)ZnC_(0.7)@C进行可控的空气氧化处理去除碳层,设计制备了一种具有双核壳结构的Ni_(3)ZnC_(0.7)@Ni@C新型催化剂.该催化剂的特点是金属镍小团簇均匀分散在中心Ni_(3)ZnC_(0.7)纳米粒子上,而Ni_(3)ZnC_(0.7)@Ni被全部包裹在多孔碳壳中.利用高角度环形暗场扫描透射电子显微镜、高分辨透射电镜、热重分析和Ar离子溅射X射线光电子能谱等技术进行了表征,并提出了氧化过程中催化剂组成与结构的变化规律.实验结果表明,Ni_(3)ZnC_(0.7)@Ni@C催化剂在丁二烯选择性加氢反应中表现出较好的活性和稳定性,其性能超过了Ni_(3)ZnC_(0.7)@C和很多文献报道的镍催化体系,如Ni_(3)InC0.5和Ni_(3)In合金等.此外,本文还发现Ni_(3)ZnC_(0.7)@Ni@C催化剂在初始反应阶段的积炭行为具有自限性.相对于碳载体本身,反应中原位沉积的少量碳质(“软”积炭)能够在更低温度下被氧化,并且碳沉积在反应初期达到平衡,该现象不仅能够抑制催化剂的进一步失活,还可以显著提高总丁烯的选择性.在温和反应条件下,Ni_(3)ZnC_(0.7)@Ni@C催化剂能够获得高于93%的总丁烯选择性和98%的转化率,并且在长达80 h测试中依然保持催化性能稳定.综上,本文通过利用镍及其间隙化合物的独特性质,开发了一种高活性、高选择性的非贵金属催化剂.通过调节电子结构、表面反应性以及潜在的协同效应,显著提高了催化性能.此外,研究发现反应中原位生成的“软”积炭不仅能够抑制催化剂的过度失活,还有助提高催化剂的选择性和稳定性.上述结果对于研究存在类似积炭问题的其他催化过程具有借鉴意义. 展开更多
关键词 丁二烯加氢 间隙化合物 Ni_(3)ZnC_(0.7)@Ni@C 稳定性 结构演变
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Synthesis of 3D Hexagram-Like Cobalt–Manganese Sulfides Nanosheets Grown on Nickel Foam: A Bifunctional Electrocatalyst for Overall Water Splitting 被引量:5
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作者 jingwei li Weiming Xu +5 位作者 Jiaxian Luo Dan Zhou Dawei Zhang licheng Wei Peiman Xu Dingsheng Yuan 《Nano-Micro Letters》 SCIE EI CAS 2018年第1期53-62,共10页
The exploration of low-cost and efficient bifunctional electrocatalysts for oxygen evolution reaction and hydrogen evolution reaction through tuning the chemical composition is strongly required for sustainable resour... The exploration of low-cost and efficient bifunctional electrocatalysts for oxygen evolution reaction and hydrogen evolution reaction through tuning the chemical composition is strongly required for sustainable resources. Herein, we developed a bimetallic cobalt–manganese sulfide supported on Ni foam(CMS/Ni) via a solvothermal method. It has discovered that after combining with the pure Co_9S_8 and Mn S, the morphologies of CMS/Ni have modulated. The obtained three-dimensionally hexagram-like CMS/Ni nanosheets have a significant increase in electrochemical active surface area and charge transport ability. More than that, the synergetic effect of Co and Mn has also presented in this composite. Benefiting from these, the CMS/Ni electrode shows great performance toward hydrogen evolution reaction and oxygen evolution reaction in basic medium, comparing favorably to that ofthe pure Co_9S_8/Ni and Mn S/Ni. More importantly, this versatile CMS/Ni can catalyze the water splitting in a twoelectrode system at a potential of 1.47 V, and this electrolyzer can be efficiently driven by a 1.50 V commercial dry battery. 展开更多
关键词 Bifunctional electrocatalysts Oxygen evolution reaction Hydrogen evolution reaction Cobalt–manganese sulfides Water splitting
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Three-dimensional lily-like CoNi_2S_4 as an advanced bifunctional electrocatalyst for hydrogen and oxygen evolution reaction 被引量:4
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作者 jingwei li Qiuna Zhuang +3 位作者 Peiman Xu Dawei Zhang licheng Wei Dingsheng Yuan 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第8期1403-1410,共8页
Designing low-cost, highly efficient, and stable bifunctional electrocatalysts for both hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is of vital significance for water splitting.Herein, thre... Designing low-cost, highly efficient, and stable bifunctional electrocatalysts for both hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is of vital significance for water splitting.Herein, three-dimensional lily-like CoNi_2S_4 supported on nickel foam(CoNi_2S_4/Ni) has been fabricated by sulfuration of the Co–Ni precursor. As expected, CoNi_2S_4/Ni possesses such outstanding electrocatalytic properties that it requires an overpotential of only 54 mV at 10 mA cm^(-2) and 328 mV at 100 mA cm^(-2) for HER and OER, respectively. Furthermore, by utilizing the CoNi_2S_4/Ni electrodes as bifunctional electrocatalysts for overall water splitting, a current density of 10 mA cm^(-2) can be obtained at a voltage of only 1.56 V. 展开更多
关键词 Bifunctional electrocataly stHydrogen evolution reaction Oxygen evolutionreaction Lily‐likeCoNi2S4 Overall water splitting
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Hydroformylation of methyl-3-pentenoate over a phosphite ligand modified Rh/SiO_2 catalyst 被引量:1
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作者 Xianming li Yunjie Ding +3 位作者 Guiping Jiao jingwei li li Yan Hejun Zhu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2008年第4期351-354,共4页
A phosphite ligand modified Rh/SiO2 catalyst has been developed for hydroformylation of internal olefins to linear aldehydes, which showed high activity and regioselectivity and could be separated easily by filtration... A phosphite ligand modified Rh/SiO2 catalyst has been developed for hydroformylation of internal olefins to linear aldehydes, which showed high activity and regioselectivity and could be separated easily by filtration after reaction in an autoclave. Effects of reaction temperature and syngas pressure on the performances of the catalyst in the reaction were also investigated. 展开更多
关键词 Rh/SiO2 PHOSPHITE HYDROFORMYLATION internal olefins linear aldehydes
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3层共挤模具交汇夹角对单层厚度及离模胀大的调控机制
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作者 刘磊 王鑫杨 +4 位作者 李经纬 刘奎 杨天洋 靳国宝 赵丹阳 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2023年第12期71-79,共9页
聚合物共挤模具结构对制品成型质量有着重要影响,尤其是模具交汇夹角对熔体厚度及离模胀大有着明显的影响。文中采用Carreau黏度模型和Picard迭代计算方法,深入研究了外层为聚十二内酰胺(PA12)、中层为乙烯-醋酸乙烯酯共聚物(EVA)和内... 聚合物共挤模具结构对制品成型质量有着重要影响,尤其是模具交汇夹角对熔体厚度及离模胀大有着明显的影响。文中采用Carreau黏度模型和Picard迭代计算方法,深入研究了外层为聚十二内酰胺(PA12)、中层为乙烯-醋酸乙烯酯共聚物(EVA)和内层为聚丙烯(PP)的3层微管共挤过程的数值模拟。结果表明,外层熔体交汇夹角增大时,PA12厚度增加,EVA和PP厚度减小,内外径均减小,胀大率增大;中层熔体交汇夹角增大时,EVA厚度增大,PA12和PP厚度减小,内外径均减小,胀大率减小;两处熔体交汇夹角同时增大时,PA12和EVA厚度增大,PP厚度减小,内外径均减小,胀大率增大。3层共挤实验证明了模拟结果的正确性与有效性。该研究结果能够为聚合物多层共挤模具的流道结构设计提供了有价值的参考。 展开更多
关键词 聚合物共挤 交汇夹角 熔体厚度 离模胀大 模具设计
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Nucleation and growth control for iron-and phosphorus-rich phases from a modified steelmaking waste slag 被引量:1
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作者 Juncheng li Guoxuan li +7 位作者 Feng Qiu Rong Wang Jinshan liang Yi Zhong Dong Guan jingwei li Seetharaman Sridhar Zushu li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第2期378-387,共10页
Recovering the iron(Fe)and phosphorus(P)contained in steelmaking slags not only reduces the environmental burden caused by the accumulated slag,but also is the way to develop a circular economy and achieve sustainable... Recovering the iron(Fe)and phosphorus(P)contained in steelmaking slags not only reduces the environmental burden caused by the accumulated slag,but also is the way to develop a circular economy and achieve sustainable development in the steel industry.We had pre-viously found the possibility of recovering Fe and P resources,i.e.,magnetite(Fe_(3)O_(4)) and calcium phosphate(Ca_(10)P_(6)O_(25)),contained in steel-making slags by adjusting oxygen partial pressure and adding modifier B_(2)O_(3).As a fundamental study for efficiently recovering Fe and P from steelmaking slag,in this study,the crystallization behavior of the CaO-SiO_(2)-FeO-P_(2)O_(5)-B_(2)O_(3) melt has been observed in situ,using a confocal scanning laser microscope(CLSM).The kinetics of nucleation and growth of Fe-and P-rich phases have been calculated using a classical crys-tallization kinetic theory.During cooling,a Fe_(3)O_(4) phase with faceted morphology was observed as the 1st precipitated phase in the isothermal interval of 1300-1150℃,while Ca_(10)P_(6)O_(25),with rod-shaped morphology,was found to be the 2nd phase to precipitate in the interval of 1150-1000℃.The crystallization abilities of Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases in the CaO-SiO_(2)-FeO-P_(2)O_(5)-B_(2)O_(3) melt were quantified with the in-dex of(T_(U)−T_(I))/T_(I)(where T_(I) represents the peak temperature of the nucleation rate and TU stands for that of growth rate),and the crystalliza-tion ability of Fe_(3)O_(4) was found to be larger than that of Ca_(10)P_(6)O_(25) phase.The range of crystallization temperature for Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases was optimized subsequently.The Fe_(3)O_(4) and Ca_(10)P_(6)O_(25) phases are the potential sources for ferrous feedstock and phosphate fertilizer,respectively. 展开更多
关键词 steelmaking slag MAGNETITE calcium phosphate NUCLEATION GROWTH KINETICS
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Simultaneously removal of P and B from Si by Sr and Zr co-addition during Al–Si low-temperature solvent refining
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作者 Chen Chen jingwei li +2 位作者 Qiuxia Zuo Boyuan Ban Jian Chen 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第2期365-377,共13页
To remove the key impurity elements,P and B,from primary Si simultaneously,Sr and Zr co-addition to Al-Si alloy systems during solvent refining has been investigated.Sr reacts with Al,Si,and P in the melt to form a P-... To remove the key impurity elements,P and B,from primary Si simultaneously,Sr and Zr co-addition to Al-Si alloy systems during solvent refining has been investigated.Sr reacts with Al,Si,and P in the melt to form a P-containing Al_(2)Si_(2)Sr phase and Zr reacts with B to form a ZrB_(2) phase.In the Al-Si-Sr-Zr system,high removal fractions of P and B in the primary Si,with 84.8%-98.4%and 90.7%-96.7%,respectively,are achieved at the same time,respectively.The best removal effect is obtained in the sample with the addition of Sr-32000+Zr-3000μg·kg^(-1),and the removal fractions of P and B in the purified Si reach 98.4%and 96.1%.Compared with the Sr/Zr single-addition,the removal effects of Sr and Zr co-addition on P and B do not show a significant downward trend,indicating that the nucleation and growth of the B/P-containing impurity phases are mutually independent.Finally,an evolution model is proposed to describe the nucleation and the growth stages of Sr/Zr-containing compound phases,which reveals the interaction between the impurity phases and the primary Si. 展开更多
关键词 Al2Si2Sr phase zirconium boride phase phase directional solidification solvent refining
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High-Performance Flexible Asymmetric Supercapacitor Based on CoAl-LDH and rGO Electrodes 被引量:10
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作者 Shuoshuo li Pengpeng Cheng +5 位作者 Jiaxian Luo Dan Zhou Weiming Xu jingwei li Ruchun li Dingsheng Yuan 《Nano-Micro Letters》 SCIE EI CAS 2017年第3期72-81,共10页
A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive el... A flexible asymmetric supercapacitor(ASC)based on a Co Al-layered double hydroxide(Co Al-LDH)electrode and a reduced graphene oxide(r GO) electrode was successfully fabricated. The Co Al-LDH electrode as a positive electrode was synthesized by directly growing Co Al-LDH nanosheet arrays on a carbon cloth(CC)through a facile hydrothermal method, and it delivered a specific capacitance of 616.9 F g^(-1)at a current density of1 A g^(-1). The r GO electrode as a negative electrode was synthesized by coating r GO on the CC via a simple dipcoating method and revealed a specific capacitance of110.0 F g^(-1)at a current density of 2 A g^(-1). Ultimately,the advanced ASC offered a broad voltage window(1.7 V)and exhibited a high superficial capacitance of1.77 F cm^(-2)at 2 m A cm^(-2)and a high energy density of0.71 m Wh cm^(-2)at a power density of 17.05 m W cm^(-2),along with an excellent cycle stability(92.9% capacitance retention over 8000 charge–discharge cycles). 展开更多
关键词 Flexible asymmetric supercapacitor Layer double hydroxides Reduced graphene oxide Cycle stability
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Pantograph-catenary electrical contact system of high-speed railways:recent progress,challenges,and outlooks 被引量:8
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作者 Guangning Wu Keliang Dong +10 位作者 Zhilei Xu Song Xiao Wenfu Wei Huan Chen Jie li Zhanglin Huang jingwei li Guoqiang Gao Guozheng Kang Chuanjun Tu Xingyi Huang 《Railway Engineering Science》 2022年第4期437-467,共31页
As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed rail... As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed railways all over the world,some commercialized lines are built for covering the remote places under harsh environment,especially in China;these environmental elements including wind,sand,rain,thunder,ice and snow need to be considered during the design of the pantograph-catenary system.The pantograph-catenary system includes the pantograph,the contact wire and the interface—pantograph slide.As the key component,this pantograph slide plays a critical role in reliable power transmission under dynamic condition.The fundamental material characteristics of the pantograph slide and contact wire such as electrical conductivity,impact resistance,wear resistance,etc.,directly determine the sliding electrical contact performance of the pantograph-catenary system;meanwhile,different detection methods of the pantograph-catenary system are crucial for the reliability of service and maintenance.In addition,the challenges brought from extreme operational conditions are discussed,taking the Sichuan-Tibet Railway currently under construction as a special example with the high-altitude climate.The outlook for developing the ultra-high-speed train equipped with the novel pantograph-catenary system which can address the harsher operational environment is also involved.This paper has provided a comprehensive review of the high-speed railway pantograph-catenary systems,including its progress,challenges,outlooks in the history and future. 展开更多
关键词 High-speed railway Pantograph-catenary system Contact wire Pantograph slide Status detection
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Robust ZnS interphase for stable Zn metal anode of high-performance aqueous secondary batteries 被引量:4
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作者 lingyun Xiong Hao Fu +4 位作者 Weiwei Han Manxiang Wang jingwei li Woochul Yang Guicheng liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2022年第5期1053-1060,共8页
Although Zn metal is an ideal anode candidate for aqueous batteries owing to its high theoretical capacity,lower cost,and safety,its service life and efficiency are damaged by severe hydrogen evolution reaction,self-c... Although Zn metal is an ideal anode candidate for aqueous batteries owing to its high theoretical capacity,lower cost,and safety,its service life and efficiency are damaged by severe hydrogen evolution reaction,self-corrosion,and dendrite growth.Herein,a thickness-controlled ZnS passivation layer was fabricated on the Zn metal surface to obtain Zn@ZnS electrode through oxidation–orientation sulfuration by the liquid-and vapor-phase hydrothermal processes.Benefiting from the chemical inertness of the ZnS interphase,the as-prepared Zn@ZnS electrode presents an excellent anti-corrosion and undesirable hydrogen evolution reaction.Meanwhile,the thickness-optimized ZnS layer with an unbalanced charge distribution represses dendrite growth by guiding Zn plating/stripping,leading to long service life.Consequently,the Zn@Zn S presented 300 cycles in the symmetric cells with a 42 mV overpotential,200 cycles in half cells with a 78 mV overpotential,and superb rate performance in Zn||NH;V;O;full cells. 展开更多
关键词 Zn metal anode dendrite-free ZnS passivation layer controllable thickness chemical inertness unbalanced charge distribution
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Surface density of synthetically tuned spinel oxides of Co^(3+) and Ni^(3+) with enhanced catalytic activity for methane oxidation 被引量:4
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作者 Zeshu Zhang jingwei li +5 位作者 Ting Yi liwei Sun Yibo Zhang Xuefeng Hu Wenhao Cui Xiangguang Yang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第7期1228-1239,共12页
Spinel oxides containing Co and Ni are a promising substitute as a noble metal catalyst for methane combustion.Achieving a complete oxidation of methane under 400°C remains challenging,andhydrothermal 60 h NiClit... Spinel oxides containing Co and Ni are a promising substitute as a noble metal catalyst for methane combustion.Achieving a complete oxidation of methane under 400°C remains challenging,andhydrothermal 60 h NiClittle impact on activity,especially at high space velocities due to the long hydrothermal time with less absorbed oxygen species and crystal defects.Overall,these results help clarify methane activa-tion mechanisms and aid the development of more efficient low-cost catalysts. 展开更多
关键词 Spinel oxides Catalytic combustion of methane Porous nanosheets Active center Hydrothermal stability
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OPTIMAL DIVIDEND-PENALTY STRATEGIES FOR INSURANCE RISK MODELS WITH SURPLUS-DEPENDENT PREMIUMS 被引量:3
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作者 jingwei li Guoxin liU Jinyan ZHAO 《Acta Mathematica Scientia》 SCIE CSCD 2020年第1期170-198,共29页
This paper concerns an optimal dividend-penalty problem for the risk models with surplus-dependent premiums.The objective is to maximize the difference of the expected cumulative discounted dividend payments received ... This paper concerns an optimal dividend-penalty problem for the risk models with surplus-dependent premiums.The objective is to maximize the difference of the expected cumulative discounted dividend payments received until the moment of ruin and a discounted penalty payment taken at the moment of ruin.Since the value function may be not smooth enough to be the classical solution of the HJB equation,the viscosity solution is involved.The optimal value function can be characterized as the smallest viscosity supersolution of the HJB equation and the optimal dividend-penalty strategy has a band structure.Finally,some numerical examples with gamma distribution for the claims are analyzed. 展开更多
关键词 band strategy risk models with surplus-dependent PREMIUMS HJB equation VISCOSITY solution Gerber-shiu function
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Synthesis of hexagonal boron nitrides by chemical vapor deposition and their use as single photon emitters 被引量:1
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作者 Hongwei liu Chae Young You +5 位作者 jingwei li Patrick Ryan Galligan Jiawen You Zhenjing liu Yuting Cai Zhengtang Luo 《Nano Materials Science》 CAS CSCD 2021年第3期291-312,共22页
Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,includ... Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,including the use of site defects in hBN as single photon emitters(SPEs).In this review,we systematically summarize recent advanced strategies towards the controllable synthesis of 2D hBN using chemical vapor deposition,towards a full control of the domain size,orientation,morphology,layer number,and stacking order,etc.Moreover,we review the underlying mechanisms for single photon emission(SPE)in hBN and methods to selectively generate and tune the SPEs.Defects(e.g.,carbon substituted defects)are discussed for the potential use as emission sites.We finally give an outlook of future challenges and opportunities on desirable hBN synthesis and further investigation of SPEs in hBN,targeting to utilize hBN as single photon emitters in an industrial scale. 展开更多
关键词 hBN CVD Controllable synthesis Single photon emission
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The long-term health outcomes, pathophysiological mechanisms and multidisciplinary management of long COVID 被引量:1
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作者 jingwei li Yun Zhou +6 位作者 Jiechao Ma Qin Zhang Jun Shao Shufan liang Yizhou Yu Weimin li Chengdi Wang 《Signal Transduction and Targeted Therapy》 SCIE CSCD 2023年第12期5584-5602,共19页
There have been hundreds of millions of cases of coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).With the growing population of recovered patients,it i... There have been hundreds of millions of cases of coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).With the growing population of recovered patients,it is crucial to understand the long-term consequences of the disease and management strategies.Although COVID-19 was initially considered an acute respiratory illness,recent evidence suggests that manifestations including but not limited to those of the cardiovascular,respiratory,neuropsychiatric,gastrointestinal,reproductive,and musculoskeletal systems may persist long after the acute phase.These persistent manifestations,also referred to as long COVID,could impact all patients with COVID-19 across the full spectrum of illness severity.Herein,we comprehensively review the current literature on long COVID,highlighting its epidemiological understanding,the impact of vaccinations,organ-specific sequelae,pathophysiological mechanisms,and multidisciplinary management strategies.In addition,the impact of psychological and psychosomatic factors is also underscored.Despite these crucial findings on long COVID,the current diagnostic and therapeutic strategies based on previous experience and pilot studies remain inadequate,and well-designed clinical trials should be prioritized to validate existing hypotheses.Thus,we propose the primary challenges concerning biological knowledge gaps and efficient remedies as well as discuss the corresponding recommendations. 展开更多
关键词 MECHANISMS consequences hundreds
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Novel tools for early diagnosis and precision treatment based on artificial intelligence 被引量:2
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作者 Jun Shao Jiaming Feng +3 位作者 jingwei li Shufan liang Weimin li Chengdi Wang 《Chinese Medical Journal Pulmonary and Critical Care Medicine》 2023年第3期148-160,共13页
Lung cancer has the highest mortality rate among all cancers in the world.Hence,early diagnosis and personal-ized treatment plans are crucial to improving its 5-year survival rate.Chest computed tomography(CT)serves a... Lung cancer has the highest mortality rate among all cancers in the world.Hence,early diagnosis and personal-ized treatment plans are crucial to improving its 5-year survival rate.Chest computed tomography(CT)serves as an essential tool for lung cancer screening,and pathology images are the gold standard for lung cancer diagnosis.However,medical image evaluation relies on manual labor and suffers from missed diagnosis or misdiagnosis,and physician heterogeneity.The rapid development of artificial intelligence(AI)has brought a whole novel op-portunity for medical task processing,demonstrating the potential for clinical application in lung cancer diagnosis and treatment.AI technologies,including machine learning and deep learning,have been deployed extensively for lung nodule detection,benign and malignant classification,and subtype identification based on CT images.Furthermore,AI plays a role in the non-invasive prediction of genetic mutations and molecular status to provide the optimal treatment regimen,and applies to the assessment of therapeutic efficacy and prognosis of lung cancer patients,enabling precision medicine to become a reality.Meanwhile,histology-based AI models assist patholo-gists in typing,molecular characterization,and prognosis prediction to enhance the efficiency of diagnosis and treatment.However,the leap to extensive clinical application still faces various challenges,such as data sharing,standardized label acquisition,clinical application regulation,and multimodal integration.Nevertheless,AI holds promising potential in the field of lung cancer to improve cancer care. 展开更多
关键词 Lung cancer Artificial intelligence Diagnosis TREATMENT Precision medicine
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Boosting alkaline hydrogen evolution performance by constructing ultrasmall Ru clusters/Na^(+),K^(+)-decorated porous carbon composites
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作者 Mingxiu Duan Tie Shu +4 位作者 jingwei li Daliang Zhang li-Yong Gan Ke Xin Yao Qiang Yuan 《Nano Research》 SCIE EI CSCD 2023年第7期8836-8844,共9页
The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydroph... The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydrophilic nanocomposites of Ru clusters(~1.30 nm)anchored on Na^(+),K^(+)-decorated porous carbon(Ru/Na^(+),K^(+)-PC)through hydrothermal method and subsequent annealing treatment at 500℃.The Ru/Na^(+),K^(+)-PC exhibits ultralow overpotential of 7 mV at 10 mA·cm^(-2),mass activity of 15.7 A·mgRu^(-1)at 100 mV,and long-term durability of 20,000 cycles potential cycling and 200 h chronopotentiometric measurement with a negligible decrease in activity,much superior to benchmarked commercial Pt/C.Density functional theory based calculations show that the energy barrier of H-OH bond breaking is efficiently reduced due to the presence of Na and K ions,thus favoring the Volmer step.Furthermore,the Ru/Na^(+),K^(+)-PC effectively employs solar energy for obtaining H_(2)in both alkaline water and seawater electrolyzer.This finding provides a new strategy to construct high-performance and cost-effective alkaline HER electrocatalyst. 展开更多
关键词 hydrogen evolution reaction decorated porous carbon ultrasmall Ru clusters ELECTROCATALYSTS solar-to-hydrogen
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Influencing factors and optimization on mechanical performance of solid waste-derived rapid repair mortar
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作者 jingwei li Xiangshan Hou +5 位作者 Aiguang Jia Xin Xiao Xujiang Wang Yonggang Yao Ziliang Zhang Wenlong Wang 《Waste Disposal and Sustainable Energy》 EI CSCD 2023年第2期223-234,共12页
There is a great demand for high performance rapid repair mortar(RRM)because of the wide use of cement concrete.Solid-waste-based sulfoaluminate cement(WSAC)is very suitable as a green cementitious material for repair... There is a great demand for high performance rapid repair mortar(RRM)because of the wide use of cement concrete.Solid-waste-based sulfoaluminate cement(WSAC)is very suitable as a green cementitious material for repair materials because of its characteristics of high early-age strength and short setting time.However,the influence and optimization of various factors of WSAC-based RRM,such as water-to-RRM ratio,binder-to-sand ratio and additives,as well as the further solid waste replacement of aggregate,remain to be studied.This paper comprehensively studied the influence of the above factors on the performance of WSAC-based RRM and obtained a green high-performance RRM by optimizing these factors.The experimental results showed that the early and late strength of the obtained RRM is excellent,and the setting time and fluidity are appropriate,which reflected good mechanical properties and construction performance.Ordinary Portland cement(OPC)doping could not improve RRM strength.It was feasible to prepare RRM with gold tailing sand replacing part of the quartz sand.This paper provides data and a theoretical basis for the preparation of high-performance RRM based on solid waste,expanding the high value utilization of solid waste,which is conducive to the development of a low carbon society. 展开更多
关键词 Rapid repair mortar Solid-waste-based sulfoaluminate cement Ordinary Portland cement Pilot production Gold tailing sand Environmental friendliness
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High-Throughput Drug Screening on Borrelia garinii and Borrelia afzelii Identified Hypocrellin A as an Active Drug Candidate Against Borrelia Species
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作者 Tingting li Yuxian Xin +4 位作者 Dongxia liu Jingrong Sun jingwei li Ying Zhang Jie Feng 《Infectious Microbes & Diseases》 CSCD 2023年第2期83-92,共10页
Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured b... Lyme disease(LD)is a tick-transmitted infection caused by Borrelia burgdorferi sensu lato species,which include B.burgdorferi,Borrelia afzelii and Borrelia garinii.The majority of patients with early LD can be cured by the standard treatment,yet some still suffer from posttreatment LD syndrome.The presence of Borrelia persisters has been proposed as a contributing factor,because they cannot be completely eradicated by the currently used antibiotics for LD.Finding new pharmaceuticals targeting Borrelia persisters is crucial for developing more effective treatments.Here,we first confirmed the existence of persisters in B.garinii and B.afzelii cultures and then conducted a high-throughput screening of a customdrug library against persister-rich stationary-phase B.garinii and B.afzelii cultures.Among 2427 compounds screened,hypocrellin A(HA),anthracycline class of drugs and topical antibiotics along with some other natural compounds were identified to have strong potential for killing persisters of B.garinii and B.afzelii.HA was the most active anti-Borrelia compound,capable of eradicating stationary-phase Borrelia persisters,in particular when combined with doxycycline and/or ceftriaxone.Liposoluble antioxidant vitamin E was found to antagonize the activity of HA,indicating HA’s target is the cell membrane where HA triggers the generation of reactive oxygen species in the presence of light.HA was found to have distinct bactericidal activity against Borrelia species but had poor or no activity against gram-positive and gram-negative bacteria.Identification of the abovementioned drug candidates may help develop more effective therapies for LD. 展开更多
关键词 drug screening Borrelia afzelii Borrelia garinii persister hypocrellin A BIOFILM
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