检索结果-南通市图书馆

Caution in building a Burgers circuit for studying secondary dislocations

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第6期35卷 1192-1197页

作者： wen-sheng xu wen-Zheng Zhang Key Laboratory of Advanced Materials (MOE) School of Materials Science and EngineeringTsinghua University

As the Burgers vector of a secondary dislocation may not conform to the translation vectors in the periodic pattern in a high-resolution transmission electron microscope(HRTEM) image, a Burgers circuit directly constructed according to an HRTEM image may render a wrong Burgers vector. The HRTEM images of the habit plane(HP) of δ precipitate in an Inconel 718 alloy were re-examined by using different Burgers circuits, as an example. Evidence is found for predicted secondary dislocation associated with a down step. The Burgers vector of the dislocation is 1/6[112]/1/3[001]δ, determined with the Burgers circuit built on the reference of the displacement shift completely lattice(DSCL). It is consistent with both the calculated and the measured result of the major defects in the habit plane. Different Burgers vectors due to different Burgers circuits were explained quantitatively. The present study has a general implication for the determination of the Burgers vectors of secondary interfacial dislocations in other systems.

关键词： Dislocation Burgers vector Burgers circuit Coincidence site lattice (CSL) Displacement shift completely lattice (DSCL) Lattice correspondence

Interpretation of the Habit Plane of d Precipitates in Superalloy Inconel 718

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2018年第2期31卷 113-126页

作者： wen-sheng xu Xiao-Peng Yang wen-Zheng Zhang Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University Beijing 100084 China Oxford Instruments Beijing Office Beijing 100085 China

A calculation method based on a combination of Dg parallelism rule, good matching site（GMS） analysis, CSL/DSCL（coincidence site lattice/displacement shift complete lattice） and the O-lattice theory has been applied to interpret the observation of the habit plane（HP） of the d precipitates and the linear defects in the HP in an Inconel 718 superalloy. The small scattering in the HP orientation around an ideal rational plane is interpreted by the existence of a mixture of two types of steps with different heights and inclinations. These steps play a significant role to enhance the degree of matching in the HP. They are associated with secondary dislocations, with Burgers vectors of 1/6 （1 1 2）y/1/3（0 0 1）, and with a direction parallel to a near-invariant line along （110）y. The spacing of the secondary dislocations projected on the terrace plane is around 6.3 nm. The calculated dislocation structure is in good agreement with the observation.

关键词： Good matching site Dislocation Orientation relationship Interfacial structure Coincident site lattice

A Thermodynamic Perspective on Polymer Glass Formation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第9期41卷 1329-1341,I0004页

作者： wen-sheng xu Zhao-Yan Sun State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China

The dynamics of polymeric and other glass-forming liquids dramatically slows down upon cooling toward the glass transition temperature without any obvious significant change in their static structure.A quantitative understanding of this extraordinary dynamic slowdown remains one of the most significant challenges in condensed matter ***,extensive efforts have been devoted to explaining the dynamics of glass-forming liquids in terms of thermodynamic properties,leading to a number of semi-empirical models emphasizing distinct thermodynamic ***,a thermodynamic perspective is provided on the glass formation of polymeric and other *** begin with an overview of the thermodynamic models of glass formation,including the intuitively appealing“free volume”models,enthalpy models originally emphasized by Goldstein and later by others,and the highly influential configurational entropy-based *** review of these models is followed by a discussion of the advances that attempt to bring together some of the seemingly disparate thermodynamic viewpoints on glass formation by revealing a close interrelation between thermodynamic *** conclude this review with remarks on several key topics in this field,along with our viewpoint for future work.

关键词： Glass formation Entropy Free volume Enthalpy

Molecular Dynamics Study of Star Polymer Melts under Start-up Shear

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2022年第7期40卷 807-816页

作者： Dong-Dong Wang Kai-Feng Yu Xiao-Lei xu wen-sheng xu Key Laboratory of Automobile Materials Ministry of Education and College of Materials Science and EngineeringJilin UniversityChangchun130025China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China

It has been established that star polymers with a large number of arms display both the conventional chain relaxation and a slower interchain relaxation due to the formation of hard cores,which is called the local structural ***,we demonstrate that this unique relaxation property of multi-arm stars leads to unusual rheological *** study the response of star polymer melts with various arm numbers to start-up shear flow via nonequilibrium molecular dynamics *** simulation results indicate that the stress-strain response of multi-arm star polymer melts differs from that of star polymers with a small number of arms in both quantitative and qualitative *** the multi-arm star polymer melts exhibit an overshoot peak in the stress-strain curve both at relatively small and sufficiently large shear rates,two overshoot peaks appear when the flow strength is comparable to the relaxation time of the star *** double stress overshoot is absent in linear polymers and star polymers with a small number of arms and is evidently related to the presence of the local structural relaxation in star polymers with a large number of *** present a detailed analysis of the conformational and dynamical properties of star polymer melts under start-up shear to gain a molecular understanding of their stress response.

关键词： Simulation Star polymer Start-up shear

Stress-Structure Relationship of the Reversible Associating Polymer Network under Start-up Shear Flow

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2021年第3期39卷 387-396,I0008页

作者： Ai-Qing Liu Li-Jun Liu wen-sheng xu Xiao-Lei xu Ji-Zhong Chen Li-Jia An College of Chemistry Jilin UniversityChangchun 130012China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei230026China

We adopt Langevin dynamics to explore the stress-structure relationship of telechelic reversible associating polymer gel during startup shear flow, with shear strengths varying from Wi=12.6 to Wi=12640. At weak shear flow Wi=12.6, the shear stress proportionally increases with shear strain at short times, followed by a strain hardening behavior and then passes through a maximum(σmax, γmax) and finally decreases until it reaches the steady state. During the evolution of stress, the gel network is only slightly broken and essentially maintains its framework, and the strain hardening behavior originates from the excessive stretching of chains. On the other hand, the stress-strain curve at intermediate shear flow Wi=505.6 shows two differences from that at Wi=12.6, namely, the absence of strain hardening and a dramatic increase of stress at large strains,which is caused by the rupture of gel network at small strains and the network recovery at large strains, respectively. Finally, at very strong shear flow Wi=6319.7, the gel network is immediately broken by shear flow and the stress-strain curve exhibits similar behaviors to those of classical polymeric liquids.

关键词： Associating polymer Start-up shear Stress-structure relationship

Experimental study on desorption of soluble matter as influenced by cations in static water

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2014年第4期7卷 384-394页

作者： wen-sheng xu Li CHEN Xiao-xia TONG Xiao-ping CHEN Ping-cang ZHANG Division of Soil and Water Conservation Changjiang River Scientific Research Institute State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

With variation of drainage basin environments, desorption of soluble matter has become one of the significant erosion processes in rivers. It has a considerable impact on flow and sediment transport, as well as processes of river bed deformation and landform evolution throughout a watershed. In this study, considering influences on sediment movement, especially on cohesive sediment transport, Ca^2＋ and H^＋ were chosen as characteristic ions of soluble matter, and the total desorption quantity of Ca^2＋ and pH value when the desorption equilibrium is reached were employed as two indexes representing the desorption of soluble matter. By means of an indoor experiment, desorption of soluble matter as influenced by cations in static water was investigated. The results show that the total desorption quantity of soluble matter increases with the initial cation concentration until a maximum desorption quantity value is obtained and maintained. The total desorption quantity of soluble matter depends on properties of the specific cations in static water, and the stronger the affinity is between the cation and sediment surface, the higher the total desorption quantity will be. Finally, a strong approximate linear relationship between desorption quantities for different kinds of soluble matters was obtained, which means that variation of pH values can accurately reflect the desorption results of soluble matter.

关键词： soluble matter desorption cation sediment static water indoor experiment

Icariin plus curcumol enhances autophagy through the mTOR pathway and promotes cathepsin B-mediated pyroptosis of prostate cancer cells

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2024年第2期14卷 55-64页

作者： xu-Yun Wang wen-Jing xu Bo-Nan Li Tian-Song Sun wen sheng Department of Andrology Beijing Hospital of Traditional Chinese MedicineCapital Medical UniversityBeijing100010China Department of Dermatology The First Affiliated Hospital of Hunan University of Chinese MedicineChangsha410021China School of Integrated Chinese and Western Medicine Hunan University of Chinese MedicineChangsha410208China Andrology Laboratory Hunan University of Chinese MedicineChangsha410208China School of Rehabilitation Medicine and Health Care Hunan University of MedicineHuaihua418000China School of Traditional Chinese Medicine Hunan University of MedicineHuaihua418000China

Objective:To examine the effect of icariin plus curcumol on prostate cancer cells PC3 and elucidate the underlying ***:We employed the Cell Counting Kit 8 assay and colony formation assay to assess cell viability and *** expression was analyzed using monodansylcadaverine *** and Western blot analyses were used to evaluate protein expressions related to autophagy,pyroptosis,and the mTOR *** damage was examined using the lactate dehydrogenase ***,cathepsin B and NLRP3 were detected by ***:Icariin plus curcumol led to a decrease in PC3 cell proliferation and an enhancement of *** levels of LC3-Ⅱ/LC3-Ⅰand beclin-1 were increased,while the levels of p62 and mTOR were decreased after treatment with icariin plus *** changes were reversed upon overexpression of ***,3-methyladenine resulted in a decrease in inflammatory cytokines,pyroptosis-related protein levels,and lactate dehydrogenase concentration,compared to the icariin plus curcumol *** cathepsin B reversed the regulatory effects of icariin plus ***:Icariin plus curcumol demonstrates great potential as a therapeutic agent for castration-resistant prostate cancer by enhancing autophagy via the mTOR pathway and promoting pyroptosis mediated by cathepsin *** findings provide valuable insights into the molecular mechanisms underlying the therapeutic potential of icariin and curcumol for prostate cancer treatment.

关键词： Icariin Curcumol Autophagy mTOR Cathepsin B Pyroptosis Prostate cancer

Recent advances in bioinspired vision systems with curved imaging structures

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

Rare Metals 2024年第4期43卷 1407-1434页

作者： Ze-Ping He xun Han wen-Qiang Wu Zhang-sheng xu Cao-Feng Pan CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing100083China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing100049China ZJU-Hangzhou Global Scientific and Technological Innovation Center School of Micro-Nano ElectronicsZhejiang UniversityHangzhou311200China Institute of Microscale Optoelectronics Shenzhen UniversityShenzhen518060China

Limited by the planar imaging structure,the commercial camera needs to introduce additional optical elements to compensate for the curved focal plane to match the planar image *** results in a complex and bulky *** contrast,biological eyes possess a simple and compact structure due to their curved imaging structure that can directly match with the curved focal *** by the structures and functions of biological eyes,curved vision systems not only improve the image quality,but also offer a variety of advanced ***,we review the recent advances in bioinspired vision systems with curved imaging ***,we focus on their applications in implementing different functions of biological eyes,as well as the emerging curved neuromorphic imaging systems that incorporate bioinspired optical and neuromorphic processing *** addition,the challenges and opportunities of bioinspired curved imaging systems are also discussed.

关键词： Bioinspired Curved vision system Compound eye Chambered eye Neuromorphic

Understanding Mass Dependence of Glass Formation in Ring Polymers

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第9期41卷 1447-1461,I0008页

作者： Xiang-Yu Song Zhen-Yue Yang Qi-Lu Yuan Shang-Wei Li Zi-Qiang Tang Yue-Tong Dong Shi-Chun Jiang wen-sheng xu State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China School of Materials Science and Engineering Tianjin UniversityTianjin300072China

Having highly tunable molecular topology is one of the most important characteristics of polymers that provides these materials with a wide range of interesting and unique *** particular,ring polymers exhibit a number of properties that are markedly distinct from their linear ***,we compare and contrast the glass formation of unknotted,nonconcatenated ring and linear polymer melts having variable molecular mass based on molecular dynamics simulations of a coarse-grained *** revealing an unusual property in the structure of small rings,we discuss the mass dependence of the structural relaxation time determined from the self-intermediate scattering function over a wide range of temperatures in both ring and linear *** a general trend,we find that the characteristic temperatures(e.g.,the glass transition temperature)and fragility of glass formation increase with increasing molecular mass in linear polymers,but the mass dependences of these properties are rather weak in the family of ring polymer models considered,in broad accord with experimental ***,we show that the glass formation of ring polymers can quantitatively be described by the string model,a model that is broadly consistent with the entropy theory of glass formation and that takes the mass of string-like clusters as a molecular realization of the abstract cooperatively rearranging *** opens the possibility of applying the configurational entropy-based theories to describe the glass formation of ring polymers,once the ring topology is taken into account.

关键词： Ring polymers Glass formation String model Molecular dynamics simulation