检索结果-南通市图书馆

Science China(Technological Sciences) 2007年第2期50卷 129-137页

作者： han XueSong & hu YuanZhong State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China State Key Laboratory of Tribology Tsinghua University

Burrs (exit failure), being one of the important factors influencing the final precision of workpiece, have been widely studied. Today, with the development of manufacturing technology, the depth of cut falls into the range of nanometer or subnanometer, there may be some different disciplines dominating the burrs generation process. Molecular dynamics (MD) emthod, which is different from continuous mechanics, plays an important role in describing microscopic world. Take the example of single crystal copper, this paper carries out MD analysis micro-mechanism of burrs generation process. The results show that the burrs geometry depends on the type of workpiece (ductile or brittle). The depth of cut is decreased in the case of positive burrs generation process while the depth of cut is increased in case of negative burrs generation process. Keywords burr - molecular dynamics - micro-mechanism Supported by China Postdoctor Science Foundation (Grant No. 20060390458)

关键词： burr molecular dynamics micro-mechanism

Ab initio quantum simulation of strongly correlated materials with quantum embedding

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 1568-1578页

作者： Changsu Cao Jinzhao Sun Xiao Yuan han-Shi hu hung Q.Pham Dingshun Lv ByteDance Research Zhonghang PlazaNo.43North 3rd Ring West RoadHaidian DistrictBeijing 100089China Department of Chemistry Tsinghua UniversityBeijing 100084China Clarendon Laboratory University of OxfordOxford OX13PUUK Center on Frontiers of Computing Studies Peking UniversityBeijing 100871China ByteDance Research San JoseCA 95110USA Imperial College London London SW72AZUK

Quantum computing has shown great potential in various quantum chemical applications such as drug discovery,material design,and catalyst *** significant progress has been made in the quantum simulation of simple molecules,ab initio simulation of solid-state materials on quantum computers is still in its early stage,mostly owing to the fact that the system size quickly becomes prohibitively large when approaching the thermodynamic *** this work,we introduce an orbital-based multifragment approach on top of the periodic density matrix embedding theory,resulting in a significantly smaller problem size for the current near-term quantum *** demonstrate the accuracy and efficiency of our method compared with the conventional methodologies and experiments on solid-state systems with complex electronic *** include spin-polarized states of a hydrogen chain(1D-H),the equation of state of a boron nitride layer(h-BN)as well as the magnetic ordering in nickel oxide(NiO),a prototypical strongly correlated *** results suggest that quantum embedding combined with a chemically intuitive fragmentation can greatly advance quantum simulation of realistic materials,thereby paving the way for solving important yet classically hard industrial problems on near-term quantum devices.

关键词： quantum embedding thereby

Developing in situ electron paramagnetic resonance characterization for understanding electron transfer of rechargeable batteries

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第10期16卷 11992-12012页

作者： Bin Wang Wanli Wang Kang Sun Yujie Xu Yi Sun Qiang Li han hu Mingbo Wu State Key Lab of Heavy Oil Processing Institute of New EnergyCollege of Chemical EngineeringChina University of Petroleum(East China)Qingdao 266580China Institute of Chemical Industry of Forest Products Chinese Academy of ForestryNanjing 210042China College of Physics Qingdao UniversityQingdao 266071China

Electrochemical energy storage devices are pivotal in achieving“carbon neutrality”by enabling the storage of energy generated from renewable *** facilitate the development of these devices,it is important to gain insight into the underlying the single-/multi-electron transfer *** can be achieved through in-time detection under operational conditions,but there are limited tools available for monitoring electron transfer under operando *** paramagnetic resonance(EPR)is a powerful technique that can meet these expectations,as it is highly sensitive to unpaired electrons and can detect changes of paramagnetic *** the long history of in situ electrochemical EPR research,its potential has been surprisingly underutilized due to the need for strict operando cell design under special testing *** review comprehensively summarizes recent efforts to understand energy storage mechanisms using in situ/operando EPR,with the aim of drawing researchers’attention to this powerful *** introducing the fundamental principles of EPR,we describe the critical advances made in detecting batteries using operando EPR,along with the remaining challenges and opportunities for future development of this technology in *** emphasize the need for strict operando cell design and the importance of designing experiments that closely mimic real-world *** believe that this review will provide innovative solutions to solve tough problems that researchers may encounter during their battery research,and ultimately contribute to the development of more efficient and sustainable energy storage devices.

关键词： electron paramagnetic resonance in situ energy storage battery

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于阴离子交换膜电解水的离聚物研究进展

材料导报 2024年第8期38卷 24-34页

作者：赵涔凯邹杰鑫王旻李思明赵微张时林滕珏瑾王艳皎吴明铂胡涵李亚伟中国石油大学(华东)化学化工学院重质油国家重点实验室山东青岛266580 青岛海尔智能技术研发有限公司山东青岛266101 山西大学化学化工学院太原030006 能量转换与储存材料山西省重点实验室太原030006

在能源日益匮乏的今天,氢能作为一种可再生、绿色环保的新型能源成为全球节能降碳的重要载体。传统的碱水电解(Alkaline water electrolysis,AWE)制氢要求较高pH的碱液作为电解液,而且只能在低电流密度下工作;质子交换膜电解水(Proton e... 详细信息

在能源日益匮乏的今天,氢能作为一种可再生、绿色环保的新型能源成为全球节能降碳的重要载体。传统的碱水电解(Alkaline water electrolysis,AWE)制氢要求较高pH的碱液作为电解液,而且只能在低电流密度下工作;质子交换膜电解水(Proton exchange membrane water electrolysis,PEMWE)制氢技术具有电流密度大、效率高的特点,被人们视为最有前景的电解水制氢技术,但是其昂贵的催化剂以及所需的高耐酸性部件成为制约PEMWE发展的重要因素。阴离子交换膜电解水(Anion exchange membrane water electrolysis,AEMWE)作为一种新兴的技术,可以实现低成本“绿氢”制备。相较于AWE,AEMWE避免了高浓度碱液的循环;相较于PEMWE,AEMWE则具有成本低、腐蚀性低等优势。离聚物作为关键部件膜电极(Membrane electrode assembly,MEA)中三相界面(Triple phase boundary,TPB)的重要组成部分,对AEMWE内部催化作用和水管理能力起着重要作用。本文首先围绕AEMWE技术原理和离聚物在AEMWE中的作用进行了概述,随后对常见的不同种类的阴离子离聚物结构及特点进行了总结,最后从结构、含量以及添加剂调控三种调控策略入手,针对如何调控离聚物以达到更加优异的电解性能进行了具体的分析总结。

关键词：阴离子交换膜电解水离聚物三相界面调控策略

Experimental study on jet pulse assembly design and numerical simulation

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2020年第1期17卷 222-231页

作者： Liang Xue hu han Dian Wang Xian-Bo Liu He Liu Zhi-Qiang Yu China University of Petroleum–Beijing Beijing 102249China Bohai Drilling Engineering Technology Research Institute Tianjin 300280China

Jet pulse assembly is one of the main components of jet hydraulic *** pressure wave characteristics produced by jet pulse assembly have an important influence on the performance of the *** this paper,the structure and working principle of jet pulse assembly are studied,the mechanical analysis model of piston rod is established,the dynamic resistance ratio formula of jet pulse assembly is deduced,and the numerical simulation test of 89-mm jet pulse assembly structure parameters is carried *** results show that the piston rod downward stroke is driven by both the jet element driving force and the throttle plate load driving force,and can stably *** driving force of the piston rod upward stroke jet element is opposite to the load acting force of the throttle disc,and the jet driving force needs to be greater than the load resistance of the throttle disc to stably *** dynamic resistance ratio formula is *** the area of the end of the piston rod is reduced,the resistance of the throttle disc is reduced and the jet power is increased,thus solving the problem of insufficient power of the piston rod in the upstroke and ensuring the normal operation of the *** groups of numerical simulation tests were carried out,and it was found that the pressure amplitude and pressure drop of the tool decreased significantly with the increase of the tool size,and the error between the numerical simulation value and the theoretical calculation value was less than 9%,which verified the correctness of the *** is suggested to select tools on site according to the drilling construction situation to ensure the drilling effect.

关键词： Friction reduction and torsion Jet pulse assembly Dynamic resistance ratio formula Pressure amplitude Numerical simulation

Study on the Interaction between CdSe Quantum Dots and Bovine Serum Albumin with Ultraviolet Visible Absorption Spectroscopy

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2006年第7期17卷 961-964页

作者： He You han De Hong hu Jian Gong LIANG Zong Hai SHENG College of Science MOA Key Laboratory of Food Safety Evaluation Huazhong Agricultural University Wuhan 430070

The interaction of CdSe quantum dots （QDs） with bovine serum albumin （BSA） has been investigated with ultraviolet visible absorption spectroscopy （UVAS）. It was found that the absorption intensity of CdSe QDs significantly decreased after adding BSA solution, showing that CdSe QDs were bonded to BSA. The binding molar ratio was 1：1 and the binding constant was 9.7 × 10^6 L mol^-1.

关键词： CdSe quantum dots bovine serum albumin interaction.

Effective regulation mechanisms of Fe-Ni(oxy)hydroxide:Ni-rich heteroatomic bonding(Ni–O–Fe–O–Ni)is essential

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第10期16卷 12026-12034页

作者： Ruo-Yao Fan hui-Ying Zhao Zi-Yi Zhao Wen-hui hu Xin Liu Jian-Feng Yu han hu Yong-Ming Chai Bin Dong State Key Laboratory of Heavy Oil Processing College of Chemistry and Chemical EngineeringChina University of Petroleum(East China)Qingdao 266580China Stanford PULSE Institute SLAC National Accelerator LaboratoryMenlo ParkCA 95025USA

Although Fe-Ni combination performs well in transition metal-based oxygen evolution reaction(OER)electrocatalysts,there are lack of clear and general regulations mechanism to fully play the synergistic catalytic ***,we made the utmost of the interaction of Fe–Ni heteroatomic pair to obtain a highly active Fe-Ni(oxy)hydroxide catalytic layer on iron foam(IF)and nickel foam(NF)by in-situ electrochemical deposition and rapid surface reconstruction,which only required 327 and 351 mV overpotential to provide a large current of 1,000 mA·cm^(−2),*** results confirm that the moderate Ni-rich heteroatomic bonding(Ni–O–Fe–O–Ni)formed by adjusting the Ni/Fe ratio on the catalyst surface is important to offer predominant OER *** is a key component that enhances OER activity of Ni(O)OH,but Fe-rich structural surface formed by Fe–O–Ni–O–Fe bonding is not ***,the remarkable oxygen evolution performance of the prepared Ni2Fe(O)OH/IF and FeNi2(O)OH/NF can be chalked up to the optimized electronic structure of Fe–Ni heteroatomic bonding,the efficient gas spillover,the fast electron transport,and nanosheet clusters *** summary,our work suggests a comprehensive regulation mechanism for the construction of efficient Fe-Ni(oxy)hydroxide catalytic layer on inexpensive,stable,and self-supporting metallic material surface.

关键词： Fe-Ni(oxy)hydroxide oxygen evolution reaction(OER) heteroatomic bonding Ni-rich structure regulation mechanisms

Identifying and localizing of seismogenic electromagnetic anomalies from data observed by permanent MT stations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第5期67卷 1698-1713页

作者： Bing han Wenbao hu Guoze ZHAO Ji TANG State Key Laboratory of Earthquake Dynamics Institute of GeologyBeijing 100029China Key Laboratory of Exploration Technologies for Oil and Gas Resources of Ministry of Education Yangtze UniversityWuhan 430100China

In this research, an arbitrarily oriented electric dipole at subsurface is used to simulate Seismogenic Electromagnetic(SEM) radiation emanating from a seismic zone during its gestation phase. Analytical synthesis of responses at the Lijiang magnetotelluric(MT) station has revealed that SEM radiation could induce identifiable anomalies in the electromagnetic(EM)spectrum, apparent resistivity and phase within specific frequency bands. Background variations were extracted from long-term observation data of Dali and Lijiang MT stations, enabling the identification of SEM anomalies related to the Yunlong and Yangbi earthquakes. Multiple parameters of dipole sources at subsurface were obtained by applying the Differential Ant Colony Optimization(DACO) algorithm to anomalous data of two stations with multi-frequencies and various response functions. The spatial distribution of these predicted dipoles is predominantly clustered in or around the seismogenic area, with their azimuthal orientation aligning towards the seismogenic fault in general. This study has demonstrated the potential of using subsurface electric dipole simulations for SEM radiation analysis, offering a feasible approach for the prediction and understanding of seismogenic zones.

关键词： MT responses Identifying SEM anomaly Vector electric dipole responses Localizing SEM sources by inversion

复合曲线型进料体旋流器数值分析和试验性能探究

在线全文

学校读者我要写书评

暂无评论

有色金属（选矿部分） 2024年第2期 81-89页

作者：梁志涛李峰韩虎王延超纪祥飞苏州城市学院智能制造与智慧交通学院江苏苏州215104 临沂大学机械与车辆工程学院山东临沂276000

水力旋流器是一种常见的固液分离设备,但由于其自身结构的限制,致使旋流器分级精度不高。进料体作为多相流进入旋流器的首要通道,对旋流器分级性能有着重要影响,但进料体内高湍流场引起的湍流扩散以及颗粒间的相互碰撞挤压造成的颗粒分... 详细信息

水力旋流器是一种常见的固液分离设备,但由于其自身结构的限制,致使旋流器分级精度不高。进料体作为多相流进入旋流器的首要通道,对旋流器分级性能有着重要影响,但进料体内高湍流场引起的湍流扩散以及颗粒间的相互碰撞挤压造成的颗粒分级精度低等问题亟待解决。因此,设计了一种复合曲线式进料体结构旋流器,通过对进料体内部流场和颗粒运动调控,降低细颗粒进入底流的比例,从而达到提高分级精度的目的。采用数值分析法探究了直线式、渐开线式、涡状线式、直线导流式以及复合曲线式五种进料体结构旋流器内的流场特性和分级性能特性,突出了复合曲线式进料体旋流器的优越性,分别从压力场、速度场、分级效率等方面进行了全方位探究,最后对其进行了试验探究。结果表明,复合曲线式进料体结构相比于其他进料体结构具有更好的细颗粒分级性能,且内部流场更加稳定,同时等压面分布呈规律性变化,颗粒运动更加平稳。复合曲线式进料体的切向速度明显高于其他进料体结构,颗粒获得更大离心推动力,颗粒更易分级。通过试验探究发现,复合曲线式进料体旋流器的质效率为46.32%,比常规进料体质效率提高了7.32%,复合曲线式型底流中-24μm颗粒含量比常规型降低了15.07%。溢流中-24μm颗粒含量比常规型提高了3.39%,颗粒分级精度大幅提升。

关键词：复合曲线进料体细颗粒分级精度颗粒运动旋流器

基于CEEMDAN的多时间尺度的北京市PM_(2.5)浓度影响因素研究

在线全文

学校读者我要写书评

暂无评论

中国环境管理 2024年第3期16卷 131-142页

作者：叶紫涵刘婵谭章禄胡翰彭胜男中国矿业大学(北京)管理学院北京100083 国家能源集团技术经济研究院北京102200

研究PM_(2.5)浓度的主要影响因素,对提升北京市空气质量具有重要意义。与以往仅限于原始时间尺度的研究不同,本文基于CEEMDAN方法考察了多时间尺度下年平均风速、城市绿化、人口密度、产业结构和能源强度对北京市PM_(2.5)浓度波动的影响... 详细信息

研究PM_(2.5)浓度的主要影响因素,对提升北京市空气质量具有重要意义。与以往仅限于原始时间尺度的研究不同,本文基于CEEMDAN方法考察了多时间尺度下年平均风速、城市绿化、人口密度、产业结构和能源强度对北京市PM_(2.5)浓度波动的影响,并与原始时间尺度的主导因素进行对比。研究发现:原始尺度的北京市PM_(2.5)浓度影响因素是不同时间尺度内影响因素合力作用结果,不同时间尺度下影响因素不同。城市绿化、人口密度、产业结构和能源强度在多时间尺度中起到短期增强波动的作用,城市绿化和产业结构是贯穿于各个时间尺度的具有趋势性,决定北京市PM_(2.5)浓度基本走势的影响因素。

关键词： PM_(2.5) 多时间尺度影响因素 CEEMDAN 空气质量