检索结果-南通市图书馆

Evolution of microstructure and intervariant boundaries ofαphase in electron beam melted and heat-treated Ti-6Al-4V alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第8期40卷 2118-2126页

作者： Ming Wang hao-qing li Hong Guo liu Feng Shu-Yu liu Xiao-Ying Fang Institute for Advanced Manufacturing Shandong University of TechnologyZibo255000China Center of Testing and Analysis Shandong University of TechnologyZibo255000China School of Mechanical Engineering Shandong University of TechnologyZibo255000China

It is important to understand the correlation between grain morphology and intervariant boundaries of theαphase after heat treatment belowβtransus of the electron beam melted(EBMed)Ti-6 Al-4 V *** electron microscopy(SEM)and electron backscatter diffraction(EBSD)analysis have shown about 99%αphase and 1%βphase in the heat-treated samples when the temperature rises to 950℃.Four distinct types ofαgrain morphology have been found:allotromorphousα,relatively coarseαplate,large precipitationαand granularα.A single peak of the intervariant boundary with the misorientation of 60°/[1120]associated with Burgers orientation relationship(OR)was found in the allotromorphousα*** intervariant boundaries mixed with a fraction of general high-angle grain boundary(GHABs,not Burgers OR)were present in the relatively coarseαplate *** only low-angle grain boundaries(LABs)with the misorientation of<5°were found in the large precipitationαgrains.βphase tends to distribute around the boundaries of relatively coarseα*** suggests that different formation mechanisms are involved in the distinct types ofαgrain morphology.

关键词： Intervariant boundaries Electron beam melting Ti-6Al-4V alloy Heat treatment

Characterization of products from photooxidation of toluene

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2006年第5期18卷 903-909页

作者： hao li-qing WANG Zhen-ya FANG li ZHANG Wei-jun WANG Wei li Cheng-xiang SHENG liu-si Laboratory of Environmental Spectroscopy Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei 230031 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230026 China

Photooxidation reaction of toluene in smog chamber systems was initiated by the UV radiation of tolucne/CH5ONO/NOx mixtures. The products of the photooxidation reaction of toluene and its subsequent reactions were analyzed directly utilizing Fourier transform infrared spectrometer （FTIR）. Detailed assignments to FTIR spectrum of gas-phase products were given. The information of some important functional groups in the products, such as, carbonyl groups （C-O）, hydroxyl groups （-OH）, carboxylic acid （- COOH）, C-C bonding, N O bonding and C-H bonding （C H）, was got from this analysis. These results were compared to those analyzed by aerosol time of flight mass spectrometer （ATOFMS）. It was found that there are some differcnccs between FTIR analysis of gas-phase products and that of particle-phase, for example, the products with carbonyl groups, which were connected to unsaturated chemical bonds, was relatively higher in the gas phase, while kctoncs, aldehydes, carboxylic acid and organonitrates were the dominant functional groups in the aerosol-phase reaction products. The possible reaction pathways of some important products in the gas phase were also discussed.

关键词： toluene photooxidation secondary organic aerosol Fourier transform infrared spectrometer smog chamber

Size distribution of the secondary organic aerosol particles from the photooxidation of toluene

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2005年第6期17卷 912-916页

作者： hao li-qing WANG Zhen-ya HUANG Ming-qiang PEI Shi-xin YANG Yong ZHANG Wei-jun Laboratory of Environmental Spectroscopy Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei 230031 China

In a smog chamber, the photooxidation of toluene was initiated by hydroxyl radical （OH.） under different experimental conditions. The size distribution of secondary organic aerosol（SOA） particles from the above reaction was measured using aerodynamic particle sizer spectrometer. It was found from our experimental results that the number of SOA particles increased with increasing the concentration of toluene. As the reaction time prolonged, the sum of SOA particles was also increased. After a reaction time of 130 min, the concentration of secondary organic aerosol particles would be kept constant at 2300 particles/cm^3. Increasing illumination power of blacklamps could significantly induce a higher concentration of secondary organic aerosol particle. The density of SOA particles would also be increased with increasing concentration of CH30NO, however, it would be decreased as soon as the concentration of CH30NO was larger than 225.2 ppm. Nitrogen oxide with initial concentration higher than 30. 1 ppm was also found to have little effect on the formation of secondary organic aerosol.

关键词： toluene hydroxyl radical secondary organic aerosol smog chamber

Observation and mitigation of image distortion in high-energy electron radiography

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第6期34卷 69-77页

作者： hao-qing li liang Sheng Chang-qing Zhang Ying-Chao Du Zheng Zhou Xiu-Feng Weng Jia-hao Xiao Hong-Qiao Yin Bin Sun Kun Wei Yang li Bao-Jun Duan Yong-Tang liu Yan-Hong Zhang Mei Zhang Yan Song Xiao-Dong Zhang Jun liu Zhu-Ming Fu qing Xu Xue Du Jian-Peng Gao Xin-Yi Wang Xin-Jian Tan Dong-Wei Hei Department of Engineering Physics Tsinghua UniversityBeijing100084China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an710024China Institute of Applied Electronics China Academy of Engineering PhysicsMianyang621900China Institute of Intelligent Machines Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei230031China Zhongke Hefei Institutes of Collaborative Research and Innovation for Intelligent Agriculture Hefei231131China

Image distortion caused by the angular misalignment of quadrupole magnets in high-energy electron radiography has been studied *** propose that the distortion originates from the coupling of the electron motions in the transverse directions,based on a theoretical analysis and the transfer-matrix *** relative angular rotation between the second and third magnetic quadrupoles was identified as the main contributor to image *** was verified by both a beam-dynamics simulation and *** strategies to mitigate this image distortion are also explored,including magnets online tuning,higher beam energy and larger magnification *** study provides criteria for designing experiments and paves the way for achieving higher image precision.

关键词： Misalignment Angular rotation Russian quadruplet Transfer matrix

Time-resolved laser-induced breakdown spectroscopy of aluminum

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2008年第5期4卷 369-370页

作者： liU Xian-yun ZHANG Wei-jun WANG Zhen-ya hao li-qing HUANG Ming-qiang Zhao Wen-wu LONG Bo Zhao Wei Laboratory of Environment Spectroscopy Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei 230031 China

We develop a system to measure the elemental composition of unprepared samples using laser-induced breakdown spec-troscopy (liBS) in our laboratory,which can be used for the determination of elements in solids,liquids and aerosols. A description of the instrumentation,including laser,sample chamber and detection,is followed by a brief discussion. The time-resolved liBS of aluminum at atmospheric pressure is presented. At the end,the possibilities and later uses of this technique are briefly discussed.

关键词：铝光谱学 liBS 烟雾剂测试技术

Omnidirectional simulation analysis of thermomechanical coupling mechanism in inertia friction welding of Ni-based superalloy

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2025年第1期38卷 202-216页

作者： Chang-an li Guoliang QIN hao WANG School of Materials Science and Engineering Shandong UniversityJinan 250061China

The coupling between heat and pressure is the kernel of inertia friction welding(IFW)and is still not fully understood.A novel 3D fully coupled finite element model based on a plastic friction pair was developed to simulate the IFW process of a Ni-based superalloy and reveal the omnidirectional thermo-mechanical coupling mechanism of the friction *** numerical model successfully simulated the deceleration,deformation processes,and peak torsional moments in IFW and captured the evolution of temperature,contact pressure,and *** simulated results were validated through measured thermal history,optical macrography,and axial *** results indicated that interfacial friction heat was the primary heat source,and plastic deformation energy only accounted for 4%of the *** increase in initial rotational speed and friction pressure elevated the peak temperature,reaching a maximum of 1525.5K at an initial rotational speed of 2000 r/min and friction pressure of 400 *** interface heat generation could form an axial temperature gradient exceeding 320K/*** radial inhomogeneities of heat generation and temperature were manifested in a concentric ring distribution with maximum heat flux and temperature ranging from 2/5 to 2/3 *** radial inhomogeneities were caused by increasing linear velocity along the radius and an opposite distribution of contact pressure,which could reach 1.7 times the set pressure at the *** circumferential inhomogeneity of thermomechanical distribution during rotary friction welding was revealed for the first time,benefiting from the 3D *** deflection and transformation of distribution in contact pressure and Mises stress were indicators of plastic deformation and transition of quasi-steady state *** critical Mises stress was 0.5 times the friction pressure in this *** presented modeling provides a reliable insight into the thermo-mechanical coupling mechanism of IFW and lays a solid found

关键词： Inertia friction welding Thermo-mechanical coupling Inhomogeneity Numerical simulation Ni-based superalloy

在线全文

学校读者我要写书评

暂无评论

敷设约束阻尼层的工字梁振动特性研究

振动工程学报 2024年第8期37卷 1320-1329页

作者：李小珍李昊卿蒋希昊毕然西南交通大学土木工程学院桥梁工程系四川成都610031

本文提出了一种计算带约束阻尼层梁振动响应的方法。以工字梁为研究对象,开展了室内振动试验,测得了不同位置的振动响应。并基于有限元法同步建立了数值仿真模型,利用模态应变能法准确计算了结构的自振频率和模态损耗因子。基于上述结果... 详细信息

本文提出了一种计算带约束阻尼层梁振动响应的方法。以工字梁为研究对象,开展了室内振动试验,测得了不同位置的振动响应。并基于有限元法同步建立了数值仿真模型,利用模态应变能法准确计算了结构的自振频率和模态损耗因子。基于上述结果,利用模态叠加法进行谐响应分析,得到了约束阻尼层工字梁的振动响应结果。将振动响应的实测值与仿真值进行对比,验证了模型的准确性。分析了设计参数(阻尼层厚度、约束层厚度)对构件自振频率、模态损耗因子及加速度总振级的影响。研究结果表明:各板件的振动响应有着相似的变化规律,腹板加速度总振级最大,底板次之,顶板最小;总体上阻尼层厚度对工字梁前5阶自振频率影响不大,而随着约束层厚度的增大,构件前5阶自振频率先减小后增大;增大阻尼层厚度和约束层厚度都能持续增大构件的模态损耗因子,进而有效降低加速度总振级,且对腹板的减振效果好于顶板和底板。

关键词：振动试验工字梁约束阻尼层模态应变能理论数值仿真

维普期刊数据库博看期刊

Findings of non-pathologic perfusion defects by CT arterial portography and non-pathologic enhancement of CT hepatic arteriography

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 1998年第6期4卷 58-60页

作者： li li, WU Pei Hong, liN hao Gao, li Jin qing, MO Yun Xian, ZHENG lie, LU li Xia, RUAN Chao Mei and CHEN lin

AIM To recognize the characteristic findings of non pathologic perfusion defects with CT arterial portography (CTAP) and nonpathologic enhancement found in CT hepatic arteriography (CTHA). METHODS The manifestations of nonpathologic perfusion defects with CTAP and non pathologic enhancement found in CTHA were analyzed in 50 patients with primary hepatocellular carcinoma. RESULTS The false positive rate of perfusion defects detected in CTAP was 15 1%. The shapes of perfusion defects were peripheral wedge, small, round, and patchy. The occurrence rate of non pathologic enhancement found in CTHA was 22 0%. The shapes of non pathologic enhancement were small, round, irregular, and wedge. CONCLUSION There was a high frequency of non pathologic perfusion defects detected with CTAP and non pathologic enhancement found in CTHA. The simultaneous use of both procedures may help decrease the false positive rate, and increase the veracity of diagnosis for hepatocellular carcinoma.

关键词： liver neoplasms/radiography carcinoma, hepato cellular/radiography hepatic arteriography tomography, X ray computed

Processing,microstructure,and mechanical properties of wire arc additively-manufactured AZ91 magnesium alloy using cold arc process

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

中国有色金属学报 2025年第1期35卷 91-104页

作者： Bai-hao CAI Ji-kang FAN Jie li Dong-qing YANG Yong PENG Ke-hong WANG Key Laboratory of Controlled Arc Intelligent Additive Technology Ministry of Industry and Information TechnologyNanjing University of Science and TechnologyNanjing 210094China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

Thin walls of an AZ91 magnesium alloy with fine equiaxed grains were fabricated via cold arc-based wire arc additive manufacturing(CA-WAAM),and the droplet transfer behaviours,microstructures,and mechanical properties were *** results showed that the cold arc process reduced splashing at the moment of liquid bridge breakage and effectively shortened the droplet transfer *** microstructures of the deposited samples exhibited layered characteristics with alternating distributions of coarse and fine *** layer-by-layer deposition,the β-phase precipitated and grew preferentially along grain boundaries,while the fineη-Al_(8)Mn_(5)phase was dispersed in the α-Mg *** mechanical properties of the CA-WAAM deposited sample showed isotropic *** ultimate tensile strength and elongation in the building direction(BD)were 282.7 MPa and 14.2%,*** microhardness values of the deposited parts were relatively uniform,with an average value of HV 69.6.

关键词： AZ91 magnesium alloy droplet transfer microstructure mechanical properties cold arc process