检索结果-南通市图书馆

Chinese Physics Letters 2011年第11期28卷 174-177页

作者： ZOU Yang CAI Jie wan ming-zhen LV Peng GUAN Qing-Feng College of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013

The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam(HCPEB)irradiation is *** is discovered that dispersed micropores with sizes of 0.1–1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB *** dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along grain boundaries and/or dislocations towards the irradiated *** is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.

关键词： pores surface mechanism

Optimizing electronic structure through point defect engineering for enhanced electrocatalytic energy conversion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2025年第1期10卷 109-131页

作者： Wei Ma Jiahao Yao Fang Xie Xinqi wang Hao wan Xiangjian Shen Lili Zhang Menggai Jiao zhen Zhou Interdisciplinary Research Center for Sustainable Energy Science and Engineering(IRC4SE2) School of Chemical EngineeringZhengzhou UniversityHenan450001China

Point defect engineering endows catalysts with novel physical and chemical properties,elevating their electrocatalytic *** introduction of defects emerges as a promising strategy,effectively modifying the electronic structure of active *** optimization influences the adsorption energy of intermediates,thereby mitigating reaction energy barriers,altering paths,enhancing selectivity,and ultimately improving the catalytic efficiency of *** elucidate the impact of defects on the electrocatalytic process,we comprehensively outline the roles of various point defects,their synthetic methodologies,and characterization ***,we consolidate insights into the relationship between point defects and catalytic activity for hydrogen/oxygen evolution and CO_(2)/O_(2)/N_(2) reduction reactions by integrating mechanisms from diverse *** underscores the pivotal role of point defects in enhancing catalytic *** last,the principal challenges and prospects associated with point defects in current electrocatalysts are proposed,emphasizing their role in advancing the efficiency of electrochemical energy storage and conversion materials.

关键词： Point defect engineering Doping Vacancy Electrocatalysis Electronic structure

油气输送管道法兰环复合轧制过程几何尺寸精度控制方法

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

塑性工程学报 2016年第2期23卷 35-40页

作者：吕中欢汪小凯华林朱乾皓万明珍戴玉同武汉理工大学现代汽车零部件技术湖北省重点实验室武汉430070 西安交通大学机械工程学院 710049 汽车零部件技术湖北省协同创新中心 430070 张家港中环海陆特锻股份有限公司张家港215626

随着我国能源装备工程建设的加速推进,对大型石油天然气管道接头、双边法兰和高压阀体环件的需求增多,复合轧环工艺是成形此类环件的新技术。针对当前油气输送管道用法兰环成形精度低、环件尺寸公差大的现状,研究了环件几何尺寸公差与... 详细信息

随着我国能源装备工程建设的加速推进,对大型石油天然气管道接头、双边法兰和高压阀体环件的需求增多,复合轧环工艺是成形此类环件的新技术。针对当前油气输送管道用法兰环成形精度低、环件尺寸公差大的现状,研究了环件几何尺寸公差与毛坯允许质量误差之间的关系,提出了此类环件复合轧制过程尺寸精度控制方法,建立了相应的轧辊位置修正数学模型,并选用两组不同质量的毛坯进行复合轧环实验来验证该几何尺寸精度控制方法。结果表明,实验得到的成形环件尺寸与数学模型计算的理论值接近,研究结论对于优质油气输送管道法兰环的精密轧制生产具有实际指导意义。

关键词：法兰环复合轧环质量误差几何尺寸精度控制

大黄鱼(Pseudosciaena crocea)leptin和cholecystokinin基因的克隆和表达特性研究

在线全文

学校读者我要写书评

暂无评论

海洋与湖沼 2017年第5期48卷 1071-1083页

作者：刘立芹王茂廷崔文涛刘婉吕振明龚理杨静文董迎辉浙江海洋大学海洋生物种质资源发掘与利用国家地方联合工程实验室舟山316022 浙江万里学院浙江省水产种质资源高效利用技术研究重点实验室宁波315100

本文克隆了两种大黄鱼(Pseudosciaena crocea)摄食调控因子胆囊收缩素(CCK)、瘦素(LEP)基因的全长序列,并对其表达特性进行了研究。结果表明,克隆得到CCK基因属硬骨鱼类的CCK1亚家族,全长900nt,编码137个氨基酸,与其他鱼类的CCK1相比序... 详细信息

本文克隆了两种大黄鱼(Pseudosciaena crocea)摄食调控因子胆囊收缩素(CCK)、瘦素(LEP)基因的全长序列,并对其表达特性进行了研究。结果表明,克隆得到CCK基因属硬骨鱼类的CCK1亚家族,全长900nt,编码137个氨基酸,与其他鱼类的CCK1相比序列组成非常保守,特别是在20氨基酸的信号肽和8个氨基酸的CCK-8活性结构区域;而克隆得到LEP基因属硬骨鱼类的LEPA亚家族,全长1290nt,编码161个氨基酸,与其他鱼类LEP相比基因同源性较差,但在3D结构上却保留了LEP经典的4个α螺旋特征。两种因子在所检测的所有组织中均有表达,但尤以脑、胃、肠消化道、肝脏等摄食及能量平衡相关组织中表达活性最高。8天的饥饿能使大黄鱼脑、消化道组织的CCK和肝脏、脂肪组织中的LEP表达显著降低(P<0.05)。该结果说明CCK和LEP可能在大黄鱼的摄食生理和能量平衡中起着重要的调控作用;本研究将为深入了解鱼类食欲调控的神经内分泌机理提供基础。

关键词：大黄鱼瘦素胆囊收缩素基因克隆表达

Numerical simulation of local and global mixing/segregation characteristics in a gas–solid fluidized bed

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2022年第4期35卷 72-86页

作者： zhen wan Youjun Lu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Researches on solids mixing and segregation are of great significance for the operation and design of fluidized bed *** this paper,the local and global mixing and segregation characteristics of binary mixtures were investigated in a gas–solid fluidized bed by computational fluid dynamics-discrete element method(CFD-DEM)coupled approach.A methodology based on solids mixing entropy was developed to quantitatively calculate the mixing degree and time of the *** mixing curves of global mixing entropy were acquired,and the distribution maps of local mixing entropy and mixing time were also *** comparing different operating conditions,the effects of superficial gas velocity,particle density ratio and size ratio on mixing/segregation behavior were *** showed that for the partial mixing state,the fluidized bed can be divided into three parts along the bed height:complete segregation area,transition area and stable mixing *** areas showed different mixing/segregation *** gas velocity promoted the local and global mixing of binary *** increase in particle density ratio and size ratio enlarged the complete segregation area,reduced the mixing degree and increased the mixing time in the stable mixing area.

关键词： Discrete element method Solids mixing Binary mixtures Fluidized bed

Instantaneous mixing characteristics of binary mixtures differing in density in a gas-solid fluidised bed

在线全文

学校读者我要写书评

暂无评论

Particuology 2020年第6期18卷 63-71页

作者： zhen wan Youjun Lu Hao wang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina

Characterisations of instantaneous mixing behaviours in fluidised beds with binary mixtures has many *** studied the instantaneous mixing characteristics of binary mixtures in a 2-D quasi gas-solid fluidised bed using a capacitance probe *** method enabled the quantitative assessment of instantaneous mixing behaviours,including mixing index,rate,and *** kinds of binary mixtures of similar size but different density were used for the transient and steady fluidisation experiments in a bubbling fluidised *** mixing curves of initially segregated binary mixtures were acquired,and the instantaneous characteristics for the entire process were *** equation was proposed to describe the mixing process and predict the mixing degree over *** comparing experiments with different working conditions,the effects of superficial gas velocity and density ratio on the mixing in the centre and at the wall of the fluidised bed were *** the stable fluidisation stage,the axial concentration profiles of the mixtures were obtained,and the mechanisms of mixing were *** showed that the mixing level increased logarithmically with time and eventually reached a relatively stable *** the superficial gas velocity and reducing the density ratio promoted mixing and reduced mixing *** superficial gas velocities tended to mix the mixtures well and quickly,regardless of the density ratio of the two components.

关键词： Binary mixtures Fluidised bed Mixing Instantaneous characteristics

Particle convective heat transfer near the wall in a supercritical water fluidized bed by single particle model coupled with CFD-DEM

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2023年第2期73卷 47-58页

作者： Tianning Zhang zhen wan Youjun Lu State Key Laboratory of Multiphase Flow in Power Engineering(SKLMFPE) Xi'an Jiaotong UniversityXi'an710049ShaanxiChina Xi'an Electronic Engineering Research Institute Xi'an710100ShaanxiChina

Supercritical water fluidized bed(SCWFB)is a promising reactor to gasify biomass or *** optimization design is closely related to wall-to-bed heat transfer,where particle convective heat transfer plays an important *** paper evaluates the particle convective heat transfer coefficient(h_(pc))at the wall in SCWFB using the single particle *** critical parameters in the single particle model which is difficult to get experimentally are obtained by the computational fluid dynamics-discrete element method(CFD-DEM).The contact statistics related to particle-to-wall heat transfer,such as contact number and contact distance,are also *** results show that particle residence time(τ),as the key parameter to evaluate h_(pc),is found to decrease with rising velocity,while increase with larger thermal boundary layer thickness.τfollows a gamma function initially adopted in the gas-solid fluidized bed,making it possible to evaluate h_(pc) in SCWFB by a simplified single particle *** theoretical predicted h_(pc) tends to increase with rising thermal gradient thickness at a lower velocity(1.5 U_(mf)),while first decreases and then increases at higher velocity(1.75 and 2 U_(mf)).h_(pc) occupies 30%-57%of the overall wall-to-bed heat transfer coefficient for a particle diameter of 0.25 *** results are helpful to predict the overall wall-to-bed heat transfer coefficient in SCWFB combined with a reasonable fluid convective heat transfer model from a theoretical perspective.

关键词： Supercritical water Fluidized bed Particle residence time Discrete element method Single particle model

Drought-induced responses of organic osmolytes and proline metabolism during pre-flowering stage in leaves of peanut (Arachis hypogaea L.)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2017年第10期16卷 2197-2205页

作者： ZHANG ming wanG Li-feng ZHANG Kun LIU Feng-zhen wan Yong-shan Key Laboratory of Crop Ecophysiology and Farming System Ministry of Agriculture/College of Agronomy Shandong Agricultural University Tai'an 271018 P.R. China

Peanut （Arachis hypogaea L.）, an improtant oil crop, usually encounters drought stress in the process of growth and development, especially at pre-flowering stage. In order to gain insight into the drought tolerance potentials based on osmolyte accumulation and metabolism of proline aspects of peanut, pot experiments were conducted with a split-plot design in Tai＇an, Shangdong Province, China in 2013 and 2014. Pre-flowering drought （PFD） stress and optinum irrigation （control, CK） were served as the main plots and the two peanut cultivars Shanhua 11 and Hua 17 served as sub-plots. Shanhua 11 was drought-tolerant cultivar and Hua 17 was drought-sensitive. The content of soluble sugars, soluble protein, free proline and other free amino acids, the activities of enzymes involved in proline metabolism, and malondialdehyde （MDA） content and ion leakage were all investigated in the two cultivars at pre-flowering stage. Results showed that PFD stress significantly increased the levels of soluble protein, free proline and free amino acid, and increased Al-pyrroline-5-car- boxylate synthetase （P-5-CS, EC 2.***.2.11） activity in the leaves of drought-tolerant and drought-sensitive cultivars. The activity of proline dehydrogenase （proDH）（EC 1.***.99.8） decreased under PFD stress in both cultivars. The leaves of the tolerant cultivar maintained higher increments of osmolyte levels, lower increments of MDA content and ion leakage, as well as a higher increased proportion of P-5-CS activity and higher inhibited proportion of proDH activity under water stress compared with the drought-sensitive cultivar. The study suggests that proline accumulation in peanut leaves under PFD can be explained by the higher enhanced activities of P-5-CS and higher inhibition of proDH. The results will provide useful information for genetic improvement of peanut under drought tolerance.

关键词： drought stress peanut (Arachis hypogaea L.) △1-pyrroline-5-carboxylate synthetase (P-5-CS) 5-ornithinetransaminase (OAT) proline dehydrogenase (proDH)

Topological Confinement in Reversibly Interlocked Polymer Networks

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第2期42卷 133-140,I0004页

作者： wan-Ting Dai zhen-Hua Xie Yu-Bin Ke Yang You Min-Zhi Rong ming-Qiu Zhang Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education GD HPPC LabIGCMESchool of ChemistrySun Yat-sen UniversityGuangzhou510275China Spallation Neutron Source Science Center China Spallation Neutron SourceDongguan523803China Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China College of Materials and Metallurgy Guizhou UniversityGuiyang550025China

Recently, we reported a series of reversibly interlocked polymer networks(RILNs), whose mechanical robustness and functionalities improvement was believed to be derived from topological interlocking of two sub-networks, although the direct evidence for the deduction is still lacking. Herein, a specially-designed RILNs system, in which the inter-component hydrogen bonds can be shielded as needed, was prepared and used to study the micro-structures of RILNs, aiming to verify the existence of mechanical interlocking in RILNs. By changing the pH of the swelling solvent, the effect exerted by the inter-component non-covalent bonds was eliminated, so detailed information of the networks structure was exposed. The small angle X-ray scattering(SAXS) and small-angle neutron scattering(SANS) results indicated that swelling-induced structural evolution of the two sub-networks mutually affected each other, even when the inter-component hydrogen bonds were absent, proving the presence of topological interlocking. The findings may help to draw a more accurate physical image and reveal the detailed structureproperty relationship of RILNs.

关键词： Reversibly interlocked polymer networks Small angle X-ray scattering Small-angle neutron scattering Topological confinement

Dielectric Characteristics and Layer Periodic Effects of Ferroelectric Superlattice BaTiO_(3)/SrTiO_(3)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第9期18卷 1271-1274页

作者： ZHANG Jiang YIN zhen ZHANG ming-Sheng CHEN wan-Chun National Laboratory of Solid State Microstructures and Center for Materials Analysis Nanjing UniversityNanjing 210093 Institute of Physics Chinese Academy of SciencesBeijing 100080

A pseudospin-phonon coupled model in double-time Green's function theory has been developed to investi- gate the dielectric susceptibility of the ferroelectric-dielectric superlattice BaTiO_(3)/SrTiO_(3) (BTO/STO). As the pseudospin-pseudospin and pseudospin-phonon interactions increase, the dielectric susceptibility changes from a narrow shape into the strong and broad shape with the peak shifting to a higher temperature region. With increasing pseudospin-phonon interaction in the BTO layer and at smallpseudospin-pseudospin interaction in BTO layer, the dielectric susceptibility was sensitively adjusted around the transition temperature of strontium titanate, and at large pseudospin-pseudospin interaction in the BTO layer, the dielectric susceptibility was increased in the high-temperature region covering the tetragonal-cubic transition temperature of barium titanate. A critical period of 10/I0 in the BTO/STO superlattice has been obtained, which is in good agreement with the experimental data of 40A, for ten unit cells.

关键词： dielectric susceptibility interaction