检索结果-南通市图书馆

热处理对Inconel 718合金电子束焊接头微观组织和性能的影响

在线全文

学校读者我要写书评

暂无评论

机械制造文摘（焊接分册） 2017年第1期 26-31页

作者：郑欣师玉英陈玉宝张伟杰中国航发哈尔滨东安发动机有限公司黑龙江哈尔滨150066

研究了"双8时效"制度和"短时效"制度对Inconel 718高温合金母材和焊缝区的金相组织、室温力学性能的影响。结果表明,焊缝区为铸造组织特征,定向生长的树枝晶内析出γ″和γ'强化相,枝晶主干细长挺直,两侧的二次枝晶以δ相为主,形态短而... 详细信息

研究了"双8时效"制度和"短时效"制度对Inconel 718高温合金母材和焊缝区的金相组织、室温力学性能的影响。结果表明,焊缝区为铸造组织特征,定向生长的树枝晶内析出γ″和γ'强化相,枝晶主干细长挺直,两侧的二次枝晶以δ相为主,形态短而直。由于"短时效"热处理的温度偏高,使γ″亚稳定相向δ稳定相转变,导致"短时效"热处理后焊件的显微硬度和强度略低于"双8时效"热处理试件,而断后伸长率基本无变化。

关键词：高温合金电子束焊时效热处理微观组织力学性能

Strain-controlled graphdiyne membrane for CO2/CH4 separation:First-principle and molecular dynamic simulation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第7期28卷 1898-1903页

作者： xin zheng Shuai Ban Bei Liu Guangjin chen State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China College of New Energy and Materials China University of PetroleumBeijing 102249China

Tensile strain of porous membrane materials can broaden their capacity in gas *** this work,using van der Waals corrected density functional theory(DFT)and molecular dynamics(MD)simulations,the performance and mechanism of CO2/CH4 separation through strain-oriented graphdiyne(GDY)monolayer were studied by applying lateral *** is demonstrated that the CO2 permeance peaks at 1.29×10^6 gas permeation units(GPU)accompanied with CO2/CH4 selectivity of 5.27×10^3 under ultimate strain,both of which are far beyond the Robeson’s ***,the GDY membrane exhibited a decreasing gas diffusion energy barrier and increasing permeance with the increase of applied tensile ***2 molecule tends to reoriented itself vertically to permeate the ***,the CO2 permeability decreases with the increase of the temperature from300 K to 500 K due to conserving of rotational freedom,suggesting an abnormal permeance of CO2 in relation to *** theoretical results suggest that the stretchable GDY monolayer holds great promise to be an excellent candidate for CO2/CH4 separation,owing to its extremely high selectivity and permeability of CO2.

关键词： Graphdiyne Strain CO2 separation Molecular dynamics Density functional theory

An accurate single descriptor for ion–π interactions

在线全文

学校读者我要写书评

暂无评论

National Science Review 2020年第6期7卷 1036-1045页

作者： Zhangyun Liu zheng chen Jinyang Xi xin Xu Collaborative Innovation Center of Chemistry for Energy Materials Key Laboratory of Molecular Catalysis and Innovative Materials MOE Key Laboratory of Computational Physical Sciences Department of Chemistry Fudan University

Non-covalent interactions between ions and π systems play an important role in molecular recognition,catalysis and biology. To guide the screen and design for artificial hosts, catalysts and drug delivery,understanding the physical nature of ion–π complexes via descriptors is indispensable. However, even with multiple descriptors that contain the leading term of electrostatic and polarized interactions, the quantitative description for the binding energies(BEs) of ion–π complexes is still lacking because of the intrinsic shortcomings of the commonly used descriptors. Here, we have shown that the impartment of orbital details into the electrostatic energy(coined as OEE) makes an excellent single descriptor for BEs of not only spherical, but also multiply-shaped, ion–π systems, highlighting the importance of an accurate description of the electrostatic interactions. Our results have further demonstrated that OEEs from a low-level method could be calibrated to BEs from a high-level method, offering a powerful practical strategy for an accurate prediction of a set of ion–π interactions.

关键词： ion–π interactions physical nature descriptors electrostatics multiply-shaped ions

The Silk Textile Embedded in Silk Fibroin Composite: Preparation and Properties

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2018年第9期36卷 1043-1046页

作者： Yu Duan xin chen zheng-Zhong Shao State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Laboratory of Advanced Materials Fudan University

Silk reinforced silk-fibroin-based composites were prepared by embedding of silk textile into regenerated silk fibroin （RSF） matrix. The breaking stress and breaking strain of the composites were found 37.7 MPa and 71.1% respectively at （95 ：t： 5）% RH. Morphological analysis was carried out to observe fracture behavior of the samples. The in vitro biodegradation test showed that the composite degraded slowly and lost 70% weight at the end of 168 h. Moreover, compared with RSF pure film, the composite kept strength and toughness much longer time. In conclusion, this composite has the potential for more accurate cytology research and biomedical tests in the future.

关键词： Silk protein Biomaterials Composite Mechanical properties Natural product

Investigations into sensing characteristics of circular thin-plate electrostatic sensors for gas path monitoring

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2014年第4期27卷 812-820页

作者： Zhongsheng chen xin Tang zheng Hu Yongmin Yang Science and Technology on Integrated Logistic Support Laboratory National University of Defense Technology

Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important performance parameters. In this paper, an analytically mathematical model of induced charge on a circular thin-plate electrode is first derived. Then the spatial sensitivity and filtering effect of the circular electrostatic sensor are investigated by numerical calculations. Finally,experimental studies are performed to testify the theoretical results. Both theoretical and experimental results demonstrate that circular thin-plate electrostatic sensors act as a low-pass filter in the spatial frequency domain, and both the spatial filtering effect and the temporal frequency response characteristics depend strongly on the spatial position and velocity of the charged particle. These conclusions can provide guidelines for the optimal design of circular thin-plate electrostatic sensors.

关键词： Circular thin-plate Electrostatic sensor Gas path monitoring Induced charge Spatial filtering effect Spatial sensitivity

在线全文

学校读者我要写书评

暂无评论

竞争环境下资金约束企业的召回风险管理策略

管理工程学报 2025年第2期39卷 262-281页

作者：陈静杨艺郑朝南邓开洋东南大学经济管理学院上海财经大学商学院香港中文大学社会科学学院

基于绩效进行采购订单分配是引入供应商竞争、提升零部件质量的一种常见手段。然而资金约束供应商为了避免后期财务困境的发生,很可能在初期削弱其质量投资以增加流动资金的持有量。由资金约束引发的质量竞争失效问题可能在制造商基于... 详细信息

基于绩效进行采购订单分配是引入供应商竞争、提升零部件质量的一种常见手段。然而资金约束供应商为了避免后期财务困境的发生,很可能在初期削弱其质量投资以增加流动资金的持有量。由资金约束引发的质量竞争失效问题可能在制造商基于保障零部件质量而实施的惩罚机制下更为严重。为此,越来越多的制造商采用保险机制提升供应商的财务能力。本文考虑召回成本随机分布,通过构建供应商的质量竞争模型,研究惩罚机制与保险机制对供应商质量竞争行为的影响。研究发现,相较于惩罚机制,保险机制使资金约束供应商更容易在低采购价格下进入市场并参与竞争。此外,惩罚机制或具有较高赔付限额的保险机制会产生“价格黑洞”。当采购价格位于“价格黑洞”中时,提高采购价格反而会带来更低的零部件质量。当保险赔付限额较低时,保险机制可形成非对称均衡,此时仅一家供应商能够进入市场。

关键词：资金约束质量竞争召回风险惩罚与保险

同方期刊数据库

Cadmium-Resistant Oyster Mushrooms from North China for Mycoremediation

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2018年第6期28卷 848-855页

作者： chen Miaomiao zheng xin chen Liang LI Xiaofang Key Laboratory of Agricultural Water Resources Centre for Agricultural Resources Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences Environment Centre Sustainable Minerals Institute The University of Queensland

Macrofungi have been advocated to be a promising remediation material for heavy metal pollution. This study aimed to screen for cadmium(Cd)-tolerant oyster mushroom strains which may be used as biomaterials for Cd remediation in North China. To this end, 43 oyster mushroom strains were collected across North China and subject to Cd inhibition test. Phylogenetic affiliation of the tolerant strains was identified using molecular fingerprinting, and representative Cd-tolerant strains were characterized in terms of their Cd sorption capacity. Two strains, JINONG21 and SUYIN6 affiliated with Pleurotus ostreatus, were found to be highly tolerant to Cd, with a minimal inhibitory concentration of 4 mg L^(-1) Cd and a maximal tolerant concentration of 80 mg L^(-1) Cd under the test conditions. Meanwhile, JINONG21 and SUYIN6 were able to absorb up to 676 mg kg^(-1) and 970 mg kg^(-1) Cd in their mycelia in the culture medium with 20 mg L^(-1) Cd, respectively. In conclusion, the P. ostreatus strains identified in this study presented an outstanding capacity of Cd tolerance and sorption and could be promising biomaterials for Cd remediation in North China.

关键词： bioaccumulation heavy metal macrofungi maximal tolerant concentration Pleurotus ostreatus remediation sorption capacity tolerant strain

在线全文

学校读者我要写书评

暂无评论

锚拉式桩板墙结构模型试验和数值模拟研究

西南民族大学学报（自然科学版） 2005年第1期31卷 94-98页

作者：李国正陈新四川大学水电学院成都610065

对一种新型的挡土结构锚拉式桩板墙,采用模型试验和有限元计算方法,研究了在不同工况下其受力作用状态,为设计和施工提供参考依据.

关键词：锚拉式桩板墙模型试验数值模拟

Primordial non-Gaussianity from LAMOST surveys

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2010年第2期10卷 107-115页

作者： Yah Gong xin Wang zheng zheng Xue-Lei chen National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Institute for Advanced Study Einstein Drive Princeton NJ 08540 USA Center of High Energy Physics Peking University Beijing 100871 China Kavli Institute for Theoretical Physics China CAS Beijing 100190 China

The primordial non-Gaussianity （PNG） in the matter density perturbation is a very powerful probe of the physics of the very early Universe. The local PNG can induce a distinct scale-dependent bias on the large scale structure distribution of galaxies and quasars, which could be used for constraining it. We study the detection limits of PNG from the surveys of the LAMOST telescope. The cases of the main galaxy survey, the luminous red galaxy （LRG） survey, and the quasar survey of dif- ferent magnitude limits are considered. We find that the Mainl sample （i.e. the main galaxy survey which is one magnitude deeper than the SDSS main galaxy survey, or r 〈 18.8） could only provide a very weak constraint on PNG. For the Main2 sample （r 〈 19.8） and the LRG survey, the 2or （95.5%） limits on the PNG parameter fNL are ｜ fNL｜〈 145 and ｜ fNL｜〈 114 respectively, which are comparable to the current limit from cosmic microwave background （CMB） data. The quasar survey could provide a much more stringent constraint, and we find that the 2a limit for ｜fNL｜ is between 50 and 103, depending on the magnitude limit of the survey. With Planck-like priors on cosmological parameters, the quasar survey with g 〈 21.65 would improve the constraint to I fNLI 〈 43 （2or）. We also discuss the possibility of further tightening the constraint by using the relative bias method proposed by Seljak.

关键词： cosmology: large scale structure