检索结果-南通市图书馆

In Situ TEM Observation on Martensitic Transformation during Tensile Deformation of SUS304 Metastable Austenitic Stainless Steel

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第3期28卷 302-306页

作者： xi-feng li Wei Ding Jian Cao li-Yan Ye Jun Chen Department of Plasticity Technology School of Materials Science and EngineeringShanghai Jiao Tong University Department of Mechanical Engineering Northwestern University

Through in situ transmission electron microscopy observation on SUS304 metastable austenitic stainless steel during stretching at room temperature,it is found that e martensite plates were induced preferentially from the sites of dislocation *** increasing deformation,some of ε thin martensite platelets disappear and reversibly transform toγ austenite without heating treatment,which is different from the previous result that ε martensite can entirely transform toα＇***,some of deformation twins appear and grow along the vertical direction of ε martensite due to（111）_γ⊥（1010）_ε.Moreover,it is directly observed that multiple transformation mechanisms via γ→ε→γ,γ→ε,γ→α′,γ→ε→α′,γ→ deformation twins →α′ can co-exist.

关键词： In situ TEM SUS304 stainless steel Martensitic transformation ε Martensite Deformation twin

Protective effect of prednisolone on ischemia-induced liver injury in rats

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2008年第27期14卷 4332-4337页

作者： Meng Wang feng Shen Le-Hua Shi Tao xi xi-feng li Xu Chen Meng-Chao Wu Eastern Hepatobiliary Surgery Hospital Second Military Medical University 225 Changhai Road Shanghai 200438 China

AIM: To investigate the effects of prednisolone on cell membrane bleb formation, calpain μ activation and talin degradation during hepatic ischemia-reperfusion injury in rats. METHODS: The hilar area of the left lateral and median lobes of rat liver (68%) was clamped for 60 min and followed by 120 min reperfusion. Prednisolone was administered at 1.0, 3.0, or 10 mg/kg at 30 min before ischemia. In addition to biochemical and microscopic analyses, activation of calpain μ was determined using specific antibodies against the intermediate (activated) form of calpain μ. Degradation of talin was also studied by Western blotting. RESULTS: In the control and prednisolone (1.0 mg/kg) groups, serum aspartate transaminase (AST) and alanine transaminase (ALT) level were elevated, and cell membrane bleb formation was observed after 120 min of reperfusion. Moreover, calpain μ activation and talin degradation were detected. Infusion of prednisolone at 3.0 or 10 mg/kg significantly suppressed serum AST and ALT, and prevented cell membrane bleb formation. At 10 mg/kg, prednisolone markedly suppressed calpain μ activation and talin degradation. CONCLUSION: Prednisolone can suppress ischemia- reperfusion injury of the rat liver. Its cytoprotective effect is closely associated with the suppression of calpain μ activation and talin degradation.

关键词： Ischemia-reperfusion Prednisolone Cell membrane bleb Calpain μ Talin

Effects of arsenic on seed germination and physiological activities of wheat seedlings

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

Journal of Environmental Sciences 2007年第6期19卷 725-732页

作者： li Chun-xi feng Shu-li SHAO Yun JIANG li-na LU Xu-yang HOU xiao-li College of life Sciences Henan Normal University Xinxiang 453007 China

The effects of arsenic （As） were investigated on seed germination, root and shoot length and their biomass and some other factors to elucidate the toxicity of As. The results showed low concentrations of As （0-1 mg/kg） stimulated seed germination and the growth of root and shoot, however, these factors all decreased gradually at high concentrations of As （5-20 mg/kg）. The contents of O2^-, MDA, soluble protein and peroxidase （POD） activity all increased with increasing As concentrations. Soluble sugar content, ascorbate peroxidase （APX）, and superoxide dismutase （SOD） activities decreased at low concentrations of As, and increased at high concentrations of As. While acetylsalicylic acid （ASA） and chlorophyll contents, catalase （CAT） activity displayed increasing trend when the concentrations of As was lower than 1 mg/kg, and then decreasing trend. By polyacrylamide gel electrophoresis （PAGE）, As induced the expression of POD isozymes of wheat seedlings. As induced the expression of CAT isozymes but inhibited the expression of SOD isozymes of wheat seedlings at concentrations lower than 1 mg/kg. However, As inhibited the expression of CAT isozymes but induced the expression of SOD isozymes at concentrations higher than 5 mg/kg. The results indicated As could exert harmfulness in the early development stage of wheat at inappropriate concentrations.

关键词： arsenic wheat germination physiological activities

Tensile deformation behavior of coarse-grained Ti-55 titanium alloy with different hydrogen additions

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 2092-2098页

作者： xi-feng li Fang-Fei Xu Lan Hu Fu-Hui Zhu Jun Chen Department of Plasticity Technology School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200030China Shanghai Aerospace Equipments Manufacturer Co. Ltd.Shanghai200245China

The effect of hydrogen addition on the deformation behavior of coarse-grained Ti-55 alloys(~20μm)was studied by uniaxial tension tests at high *** elongation of hydrogenated Ti-55 titanium alloy firstly increases and then decreases with hydrogen content increasing at 8750 *** highest elongation of 243.8%is obtained in the hydrogenated alloy with 0.1 wt%H,and the peak stress reaches a minimum value of 29.0 MPa in the hydrogenated alloy with 0.3 wt%*** with that of the unhydrogenated alloy,the elongation of the hydrogenated alloy with 0.1 wt%H increases by 41.3%and its peak stress decreases by 40.6%at 875℃.Hydrogen addition can promote the transformation of β phase and the dislocation *** hydrogen content can evidently improve the deformation properties of coarse-grained Ti-55 titanium alloy.

关键词： Coarse-grained Ti-55 titanium alloy Hydrogen addition Plastic deformation

Tsallis Entropy Based q-Gaussian Density Model and Its Application in Measurement Accuracy Improvement

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2017年第1期15卷 77-82页

作者： Xuan xie xi-feng li Qi-Zhong Zhou Yong-Le xie School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 610054China

The central limit theorem guarantees the distribution of the measurand is Gaussian when the number of repeated measurement is infinity, but in many practical cases, the number of measurement times is limited to a given number. To overcome this contradiction, this paper firstly carries out the maximum likelihood estimation for parameter q in qGaussian density model developed under the maximum Tsallis entropy principle. Then the q-Gaussian probability density function is used in the particle filter to estimate and measure the nonlinear system. The estimated parameter q is related to the ratio between the measurement variance and the given variance, which indicates that the measurement accuracy cannot be improved if we only increase the repeated measurement times. Via using the proposed q-Gaussian density model,the measurement error（the average mean square error）of the estimation results can be reduced to a considerable level where the number of repeated measurement is limited. The experimental example is given to verify the proposed model and the measurement results prove the correctness and effectiveness of it.

关键词： variance entropy overcome infinity likelihood guarantees sequentially verify carries contradiction

Dolphin Vocal Sound Generation via Deep WaveGAN

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2022年第3期20卷 282-293页

作者： Lue Zhang Hai-Ning Huang li Yin Bao-Qi li Di Wu Hao-Ran liu xi-feng li Yong-Le xie the Institute of Acoustics Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China the Key Laboratory of Science and Technology on Advanced Underwater Acoustic Signal Processing Chinese Academy of SciencesBeijing100190China the School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu611731SichuanChina

The marine biological sonar system evolved in the struggle of nature is far superior to the current artificial sonar. Therefore, the development of bionic underwater concealed detection is of great strategic significance to the military and economy. In this paper, a generative adversarial network(GAN) is trained based on the dolphin vocal sound dataset we constructed, which can achieve unsupervised generation of dolphin vocal sounds with global consistency. Through the analysis of the generated audio samples and the real audio samples in the time domain and the frequency domain, it can be proven that the generated audio samples are close to the real audio samples,which meets the requirements of bionic underwater concealed detection.

关键词： Bionic underwater concealed detection dolphin generative adversarial network(GAN) wave generative adversarial network(WaveGAN)

Compressive near-field millimeter wave imaging algorithm based on Gini index and total variation mixed regularization

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2023年第1期21卷 65-74页

作者： Jue Lyu Dong-Jie Bi Bo liu Guo Yi Xue-Peng Zheng xi-feng li li-Biao Peng Yong-Le xie Yi-Ming Zhang Ying-li Bai School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu611731China Shanghai Spaceflight Precision Machinery Institute Shanghai201600China Electrical Engineering Department Northwestern UniversityEvanston60208USA Institute of Telecommunication Satellite China Academy of Space TechnologyBeijing100094China

A compressive near-field millimeter wave(MMW)imaging algorithm is *** the compressed sensing(CS)theory,the compressive near-field MMW imaging process can be considered to reconstruct an image from the under-sampled sparse *** Gini index(GI)has been founded that it is the only sparsity measure that has all sparsity attributes that are called Robin Hood,Scaling,Rising Tide,Cloning,Bill Gates,and *** combining the total variation(TV)operator,the GI-TV mixed regularization introduced compressive near-field MMW imaging model is *** addition,the corresponding algorithm based on a primal-dual framework is also *** results demonstrate that the proposed GI-TV mixed regularization algorithm has superior convergence and stability performance compared with the widely used l1-TV mixed regularization algorithm.

关键词： Millimeter wave(MMW) Compressed sensing(CS) Gini index(GI) Total variation(TV) Signal processing Image reconstruction

Nyström kernel algorithm based on least logarithmic hyperbolic cosine loss

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2023年第3期21卷 82-93页

作者： Shen-Jie Tang Yu Tang xi-feng li Bo liu Dong-Jie Bi Guo Yi Xue-Peng Zheng li-Biao Peng Yong-Le xie School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu611731China Shanghai Spaceflight Precision Machinery Institute Shanghai201600China

Kernel adaptive filters(KAFs)have sparked substantial attraction for online non-linear learning *** is noted that the effectiveness of KAFs is highly reliant on a rational learning *** this,the logarithmic hyperbolic cosine(lncosh)criterion with better robustness and convergence has drawn attention in recent ***,existing lncosh loss-based KAFs use the stochastic gradient descent(SGD)for optimization,which lack a trade-off between the convergence speed and *** recursion-based KAFs can provide more effective filtering ***,a Nyström method-based robust sparse kernel recursive least lncosh loss algorithm is derived in this *** via measures and synthetic data against the non-Gaussian noise confirm the superiority with regard to the robustness,accuracy performance,and computational cost.

关键词： Kernel adaptive filter(KAF) logarithmic hyperbolic cosine (lncosh)loss Nyström method Recursive

Effect of grain size on high-temperature stress relaxation behavior of fine-grained TC4 titanium alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2020年第3期30卷 668-677页

作者： He-li PENG xi-feng li Xu CHEN Jun JIANG Jing-feng LUO Wei xiONG Jun CHEN Shanghai Spaceflight Precision Machinery Institute Shanghai 201600China Shanghai Engineering Technology Research Center of Near-Net Shape Forming for Metallic Materials Shanghai 201600China Institute of Forming Technology&Equipment School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200030China

In order to analyze the effect of grain size on stress relaxation(SR) mechanism,the SR tests of TC4 alloy with three kinds of grain size were performed in a temperature range of 650-750℃.A modified cubic delay function was used to establish SR model for each grain size.A simplified algorithm was proposed for calculating the deformation activation energy based on classical Arrhenius *** grain size distribution and variation were observed by microstructural *** experimental results indicate that smaller grains are earlier to reach the relaxation limit at the same temperature due to lower initial stress and faster relaxation *** SR limit at 650℃ reduces with decreasing grain *** the effect of grain size on SR limit is not evident at 700 and 750℃ since the relaxation is fully *** the increase of grain size,the deformation activation energy is improved and SR mechanism at 700℃ changes from grain rotation and grain boundary sliding to dislocation movement and dynamic recovery.

关键词： stress relaxation grain size fine-grained microstructure TC4 titanium alloy dislocation