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Influences of pre-torsion deformation on microstructure and mechanical properties of pure titanium subjected to subsequent tension deformation

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Chinese Journal of Aeronautics 2018年第4期31卷 837-844页

作者： jie LIU Fuguo LI han CHEN School of Aeronautics Northwestern Polytechnical University Xi'an 710072 China State Key Laboratory of Solid cation Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China

A series of experimental studies was carried out to investigate the influences of pretorsion on microstructure evolution, mechanical properties, and fracture appearance of pure titanium subjected to subsequent tension deformation. An introduction of pre-torsion strain can improve the materials＇ mechanical properties through micro hardness evaluation. That is, the micro hardness of tensile samples with pre-torsion deformation is much higher than that of samples processed by single torsion or tension. It can be seen from the microstructure that pre-torsion deformation can be used to refine grains better and control grains＇ morphology by combining subsequent tension. The results indicate that the grains are refined most evidently for tensile samples with 2 turn pre-torsion deformation. Moreover, fracture analysis indicates that tensile samples with pre-torsion strain can present good comprehensive performance. In conclusion, pre-torsion deformation plays an important role in improving comprehensive performance and controlling microstructure evolution on pure titanium subjected to later tension deformation.

关键词： Combined torsion and tension Fracture Mechanical properties Microstructure Pre-torsion Titanium

3D wind-induced response analysis of a cable-membrane structure

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 337-344页

作者： Jun-jie LUO Da-jian han State Key Laboratory of Subtropical Architecture Science School of Civil Engineering and Transportation South China University of Technology Guangzhou 510640 China

Wind loading is a dominant factor for design of a cable-membrane structure. Three orthogonal turbulent components, including the longitudinal, lateral and vertical wind velocities, should be taken into account for the wind loads. In this study, a stochastic 3D coupling wind field model is derived by the spectral representation theory. The coherence functions of the three orthogonal turbulent components are considered in this model. Then the model is applied to generate the three correlated wind turbulent components. After that, formulae are proposed to transform the velocities into wind loads, and to introduce the modified wind pressure force. Finally, a wind-induced time-history response analysis is conducted for a 3D cable-membrane structure. Analytical results indicate that responses induced by the proposed wind load model are 10%-25% larger than those by the con- ventional uncorrelated model, and that the responses are not quite influenced by the modified wind pressure force. Therefore, we concluded that, in the time-history response analysis, the coherences of the three orthogonal turbulent components are necessary for a 3D cable-membrane structure, but the modified wind pressure force can be ignored.

关键词： Cable-membrane structures Time-history analysis Coherence Gust response factor

Band gap analysis of periodic structures based on cell experimental frequency response functions(FRFs)

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Acta Mechanica Sinica 2019年第1期35卷 156-173,I0005页

作者： Li-jie Wu han-Wen Song School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China

An approach is proposed to estimate the transfer function of the periodic structure, which is known as an absorber due to its repetitive cells leading to the band gap phenomenon. The band gap is a frequency range in which vibration will be inhibited. A transfer function is usually performed to gain band gap. Previous scholars regard estimation of the transfer function as a forward problem assuming known cell mass and stiffness matrices. However, the estimation of band gap for irregular or complicated cells is hardly accurate because it is difficult to model the cell exactly. Therefore, we treat the estimation as an inverse problem by employing modal identification and curve fitting. A transfer matrix is then established by parameters identitled through modal analysis. Both simulations and experiments have been performed. Some interesting conclusions about the relationship between modal parameters and band gap have been achieved.

关键词： Band gap Modal analysis Parameter identification Periodic structure Transfer matrix

Acupuncture improves dendritic structure and spatial learning and memory ability of Alzheimer's disease mice

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Neural Regeneration Research 2018年第8期13卷 1390-1395页

作者： Bo-Hong Kan Jian-Chun Yu Lan Zhao jie Zhao Zhen Li Yan-Rong Suo Jing-xian han First Teaching Hospital of Tianjin University of Traditional Chinese Medicine Tianjin China Tianjin Key Laboratory of Acupuncture & Moxibustion Science Tian)in China Institute of Acupuncture and Moxibustion Research Tianjin China Tianjin University of Traditional Chinese Medicine Tianjin China

Acupuncture can improve the cognitive state of Alzheimer＇s disease, but its mechanism is not clear. Dendritic atrophy and synaptic loss in Alzheimer＇s disease brain are positively correlated with cognitive damage. Therefore, we speculated that the effect of acupuncture on improving cognitive function may be associated with reduced dendritic damage in the brain. Acupuncture at Qihai（CV6）, Zhongwan（CV12）, Danzhong（CV17）, bilateral Zusanli（ST36）, and bilateral Xuehai（SP10） acupoints was performed once a day（1-day rest after 6-day treatment） for 14 consecutive days. Senescence-accelerated mouse prone 8（SAMP8） mice without acupuncture and senescence-accelerated mouse resistant 1（SAMR1） mice were used as normal controls. After 14 days of treatment, spatial learning and memory ability of mice was assessed in each group using the Morris water maze. Dendritic changes of pyramidal cells in the hippocampal CA1 region were analyzed by quantitative Golgi staining. Our results showed that acupuncture shortened escape latency and lengthened retention time of the former platform quadrant in SAMP8 mice. Further, SAMP8 mice exhibited a significant increase in the number of apical and basal dendritic branches and total length of apical and basal dendrites after acupuncture. These results suggest that acupuncture improves spatial learning and memory ability of middle-aged SAMP8 mice by ameliorating dendritic *** can improve the cognitive state of Alzheimer＇s disease, but its mechanism is not clear. Dendritic atrophy and synaptic loss in Alzheimer＇s disease brain are positively correlated with cognitive damage. Therefore, we speculated that the effect of acupuncture on im- proving cognitive function may be associated with reduced dendritic damage in the brain. Acupuncture at Qihai （CV6）, Zhongwan （CV 12）, Danzhong （CV17）, bilateral Zusanli （ST36）, and bilateral Xuehai （SP10） acupoints was performed once a day （1-day rest after 6-day treat- ment） for 14 consecutive days

关键词： nerve regeneration Alzheimer's disease senescence-accelerated prone mouse 8 acupuncture cognition dendrite hippocampal CA 1 region Morris water maze Golgi staining neural regeneration

Thermodynamic and experimental study of high-temperature roasting of blast furnace gas ash for recovery of metallic zinc and iron

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Journal of Iron and Steel Research International 2024年第1期31卷 108-120页

作者： Zi-han Wang Jing Guo han-jie Guo Bin Li School of Metallurgical Engineering University of Science and Technology BeijingBeijing100083China School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina

A high-temperature reduction roasting method was used to achieve metallic iron and zinc recovery from blast furnace gas ash(BFA).The reduction processes for Zn-containing and Fe-containing oxides were analyzed in detail by using ther-modynamic equilibrium calculation and the principle of minimum free *** results showed that the main reaction in the system is the reduction of ZnFe_(2)_(4)and iron *** the full temperature range,iron oxides were more easily reduced than zinc *** of the amount of CO contained in the system,the reduction of ZnO to Zn was difficult to proceed below the boiling point(906℃)of *** the reduction temperature is below 906℃,the reduction process of zinc ferrate was ZnFe_(2)_(4)→ZnO;when the reduction temperature is above 906℃,its reduction process becomed ZnFe_(2)_(4)→ZnO→Zn(g).The metallization and dezincification rates of the BFA gradually increased with increasing reaction *** the C/O ratio increased,the metallization and dezincification rates first increased and then *** effect of reduction time on BFA reduction was similar to that of reaction temperature.

关键词： Blast furnace gas ash Thermodynamics Zinc removal Iron reduction High-temperature reduction roasting Integrated utilization

Evaluation of semivariogram features for objectbased image classification

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Geo-Spatial Information Science 2015年第4期18卷 159-170页

作者： xian WU Jianwei PENG jie Shan Weihong CUI School of Remote Sensing and Information Engineering Wuhan University129 Luoyu RoadWuhan 430079China Central Southern China Electronic Power Design Institute of China Power Engineering Consulting Group 668 Minzhu RoadWuhan 430071China Lyles School of Civil Engineering Purdue UniversityWest LafayetteIN 47907USA Collaborative Innovation Center of Geospatial Technology Wuhan University129 Luoyu RoadWuhan 430079China

Inclusion of textures in image classification has been shown *** paper studies an efficient use of semivariogram features for object-based high-resolution image ***,an input image is divided into segments,for each of which a semivariogram is then ***,candidate features are extracted as a number of key locations of the semivariogram *** we use an improved Relief algorithm and the principal component analysis to select independent and significant *** the selected prominent semivariogram features and the conventional spectral features are combined to constitute a feature vector for a support vector machine *** effect of such selected semivariogram features is compared with those of the gray-level co-occurrence matrix(GLCM)features and window-based semivariogram texture features(STFs).Tests with aerial and satellite images show that such selected semivariogram features are of a more beneficial supplement to spectral *** described method in this paper yields a higher classification accuracy than the combination of spectral and GLCM features or STFs.

关键词： object based image analysis image segmentation image classification texture feature semivariogram

Black-box membership inference attacks based on shadow model

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The Journal of China Universities of Posts and Telecommunications 2024年第4期31卷 1-16页

作者： han Zhen Zhou Wen'an han Xiaoxuan Wu jie School of Computer Science Beijing University of Posts and TelecommunicationsBeijing 100876China

Membership inference attacks on machine learning models have drawn significant *** current research primarily utilizes shadow modeling techniques,which require knowledge of the target model and training data,practical scenarios involve black-box access to the target model with no available *** training data further complicate the implementation of these *** this paper,we experimentally compare common data enhancement schemes and propose a data synthesis framework based on the variational autoencoder generative adversarial network(VAE-GAN)to extend the training data for shadow ***,this paper proposes a shadow model training algorithm based on adversarial training to improve the shadow model's ability to mimic the predicted behavior of the target model when the target model's information is *** conducting attack experiments on different models under the black-box access setting,this paper verifies the effectiveness of the VAE-GAN-based data synthesis framework for improving the accuracy of membership inference ***,we verify that the shadow model,trained by using the adversarial training approach,effectively improves the degree of mimicking the predicted behavior of the target *** with existing research methods,the method proposed in this paper achieves a 2%improvement in attack accuracy and delivers better attack performance.

关键词： machine learning membership inference attack shadow model black-box model

Gene Expression and Activities of SOD in Cucumber Seedlings Were Related with Concentrations of Mn^(2+),Cu^(2+),or Zn^(2+) Under Low Temperature Stress

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Agricultural Sciences in China 2009年第6期8卷 678-684页

作者： GAO Jun-jie LI Tao YU xian-chang The lnsititute of Vegetables and Flowers Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China College of Horticulture Science and Engineering State Key Laboratory of Crop Biology Shandong Agricultural University Tai＇an 271018 P.R. China Municipal Bureau of Agriculture Tai＇an 271000P.R.China Yantai Academy of Agricultural Sciences Yantai 265500 P.R.China

Effects of increasing Mn^2＋, Cu^2＋, or Zn^2＋ on SOD expressions were studied in cucumber seedlings under low temperature stress. Both gene expressions and activities of Cu/Zn-SOD and Mn-SOD in cucumber seedling leaves were induced by increasing Mn^2＋, Cu^2＋, or Zn^2＋ under low temperature stress, especially 48 h afterwards. The activities of Cu/Zn-SOD and Mn-SOD at 0 and 48 h after treatment were in accordance with their gene expression levels, which implied that the transcriptional regulation plays key roles in regulating their activities at the early stage of low temperature stress. Gene expressions of Cu/Zn-SOD and Mn-SOD declined at 96 h, but Cu/Zn-SOD and Mn-SOD activities still remain high, which suggested that Cu/Zn-SOD and Mn-SOD activities might be regulated by other factors after transcription at the later stage of low temperature stress. Therefore, we concluded that the increasing Mn^2＋, Cu^2＋, or Zn^2＋ could increase the capacity of scavenging ROS in cucumber seedlings under low temperature stress by inducing gene expressions of Cu/ Zn-SOD and Mn-SOD, elevating activities of Cu/Zn-SOD, Mn-SOD, or regulating other factors after transcription.

关键词： real-time quantitative PCR cucumber seedlings SOD low temperature stress manganese copper zinc

Test research on sticking mechanism during hot rolling of SUS 430 ferritic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 573-578页

作者： Jun-xian Liu Yong-jun Zhang Jing-tao han School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The sticking phenomenon during hot rolling of SUS 430 ferritic stainless steel was investigated by means of a two-disc type high-temperature wear tester. The test results indicate that sticking particles on the surfaces of high chromium steel （HiCr） and high-speed steel （HSS） rolls undergo nucleation, growth, and saturation stages. Grooves on the roll surface generated by grinding provide nucleation sites for sticking particles. The number of sticking particles on the HiCr roll surface is greater than that on the HSS roll surface. The average surface roughnesses （Ra） of HiCr and HSS rolls change from 0.502 and 0.493 μm at the initial stage to 0.837 and 0.530 μm at the saturation stage, respectively. The test further proves that the sticking behavior is strongly dependent on roll materials, and the HSS roll is more benefi- cial to prevent particles sticking compared with the HiCr roll under the same hot-rolling conditions.

关键词： ferritic steel stainless steel hot rolling sticking rolls