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Effect of the draw ratio in dry jet-wet spinning on aromatic copolysulfonamide fibers

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Nuclear Science and Techniques 2020年第7期31卷 1-11页

作者： Jian-Ning Wang yu-mei zhang Xiao-yun Li State Key Laboratory for Modification of Fibers and Polymer Materials College of Material Science and EngineeringDonghua UniversityShanghai 201620China Shanghai Synchrotron Radiation Facility Shanghai Advance Research InstituteChinese Academy of SciencesShanghai 201210China

Aromatic copolysulfonamide(co-PSA)fiber produced via wet spinning exhibits poor mechanical ***,dry jet-wet spinning was introduced to prepare the co-PSA *** jet-wet spinning exhibits the advantage of positive stretching to the extruded fiber before *** fibers were spun at different jet draw ratios and second draw ratios and were examined for scanning electron microscopy,mechanical properties,sound velocity,small-angle X-ray scattering(SAXS),and wide-angle X-ray scattering(WAXS).The results revealed that all the fibers exhibited a uniform and dense structure and nearly round cross section at different drawing *** strength and orientation of the fiber increased slightly as the jet draw ratio was increased to the second draw ratio of ***,the fibers formed a periodic ordered structure along the fiber ***,the strength of the fibers decreased significantly when the jet draw ratio continued to increase and the second draw ratio decreased year-on-year to maintain the total draw ratio ***,the fibers exhibited lower orientation because the molecular chain segments could not continue to extend and orient even at larger jet draw ratios,and thus they could not be further well-stretched at subsequent lower stretching ***,the periodic ordered structure disappeared and more content of entanglement structure existed in the *** the heat drawing process,the results of SAXS and WAXS indicated that the better ordered molecular chain segments within the fiber were easier to arrange and reconstruct to significantly improve the content of crystalline and mesophase structures in the ***,after the heat drawing process,the strengths of co-PSA-H2 and co-PSA-H3 fibers increased to more than 620 MPa,which is significantly higher than those of commercialized fibers and fibers reported in extant studies.

关键词： fibers spinning stretching

Facile and Large-scale Fabrication of Self-crimping Elastic Fibers for Large Strain Sensors

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Chinese Journal of Polymer Science 2021年第7期39卷 914-924页

作者： Jin-Chao yu Kang Chen Hong Ji Yang zhang yu-mei zhang Zhi-Juan Pan College of Textile and Clothing Engineering Soochow UniversitySuzhou 215123China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China

Stretchable conductive fibers offer unparalleled advantages in the development of wearable strain sensors for smart textiles due to their excellent flexibility and ***,the practical applications of these fibers in wearable devices are hindered by either contradictory properties of conductive fibers(high stretchability versus high sensing stability),or lack of manufacturing ***,we present a facile approach for highly stretchable self-crimping fiber strain sensors based on a polyether-ester(TPEE)elastomer matrix using a side-by-side bicomponent melt-spinning process involving two parallel but attached components with different shrinkage *** TPEE component serves as a highly elastic mechanical support layer within the bicomponent fibers,while the conductive component(E-TPEE)of carbon black(CB),multiwalled carbon nanotubes(MWCNTs)and TPEE works as a strain-sensitive *** addition to the intrinsic elasticity of the matrix,theTPEE/E-TPEE bicomponent fibers present an excellent form of elasticity due to *** self-crimping elongation of the fibers can provide a large deformation,and after the crimp disappears,the intrinsic elastic deformation is responsible for monitoring the strain *** reliable strain sensing range of theTPEE/E-TPEE composite fibers was 160%-270%and could be regulated by adjusting the crimp *** importantly,the TPEE/E-TPEE fibers had a diameter of 30-40 pm and tenacity of 40-50 MPa,showing the necessary *** work introduces new possibilities for fiber strain sensors produced in standard industrial spinning machines.

关键词： Conductive polyether-ester elastic fiber Side-by-side bicomponent fiber Self-crimping Strain sensing

Lipid Peroxidation and Ultrastructural Modifications in Brain after Perinatal Exposure to Lead and/or Cadmium in Rat Pups

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Biomedical and Environmental Sciences 2009年第5期22卷 423-429页

作者： yu-mei zhang XUE-ZHONG LIU HAO LU LI mei ZONG-PING LIU College of Veterinary Medicine Yangzhou University Yangzhou 225009 Jiangsu China College of Veterinary Medicine Northwest Sci-Tech University of Agriculture and Forestry Yangling 712100 Shaanxi China

Objective To assess lipid peroxidation and ultrastructural modifications in rat brains following perinatal exposure to lead （Pb） and/or cadmium （Cd）. Methods Female rats were divided into four groups： control group, Pb （300 mg/L） group, Cd group （10 mg/L） and Pb＋Cd （300 mg/L, 10 mg/L） group. The compounds were delivered in the drinking water throughout pregnancy and lactation. Results The levels of compounds in blood and brain of the Pb＋Cd group were similar to those of other groups, but the effects of Pb＋Cd on pups＇ body and brain weights were higher than on other compounds. Electron microscopy revealed that Pb and Cd had effects on mitochondrial swelling, disruption and cristae loss, Nissl body dissolution, degenerated organelles and vacuoles, cytomembrane disappearance, and nuclear chromoplasm concentration. The activity of glutathione peroxidase （GSH-Px）, superoxide dismutase （SOD）, catalase （CAT）, acetylcholinesterase （ACHE） was decreased, whereas the activity of maleic dialdehyde （MDA） was increased. Conclusion Perinatal exposure to low doses of Pb and Cd can produce alterations in lipid peroxidation and ultrastructural modifications in rat brains, and exposure to both metals can result in greater damages.

关键词： Lead Cadmium Lipid peroxidation Ultrastructure Brain Rat

Surface reconstruction from unorganized point clouds based on edge growing

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Advances in Manufacturing 2019年第3期7卷 343-352页

作者： Xu-Jia Qin Zhong-Tian Hu Hong-Bo Zheng mei-yu zhang College of Computer Science and Technology Zhejiang University of TechnologyHangzhou 310023People's Republic of China Key Laboratory of Visual Media Intelligent Processing Technology of Zhejiang Province Hangzhou 310023People's Republic of China

Owing to unorganized point cloud data,unexpected triangles,such as holes and slits,may be generated during mesh surface *** solve this problem,a mesh surface reconstruction method based on edge growing from unorganized point clouds is *** method first constructs an octree structure for unorganized point cloud data,and determines the k-nearest neighbor for each ***,the method searches for flat areas in the point clouds to be used as the initial mesh edge growth regions,to avoid incorrect reconstruction of the mesh surface owing to the growth of initial sharp ***,the optimal mesh surface is obtained by controlling the mesh edge growing based on compulsive restriction and comprehensive optimization *** experimental results of mesh surface reconstruction show that the method is feasible and shows high reconstruction performance without introducing holes or slits in the reconstructed mesh surface.

关键词： Mesh surface reconstruction Point clouds Edge growing Octree

Amethod for sharing dynamic geometry information in studies on liquid-based detectors

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Nuclear Science and Techniques 2021年第2期32卷 101-111页

作者： Shu zhang Jing-Shu Li Yang-Jie Su yu-mei zhang Zi-yuan Li Zheng-yun You School of Physics Sun Yat-Sen UniversityGuangzhou 510275China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

Liquid-based detectors are widely used in particle and nuclear physics *** fixed method is used to construct the geometry in detector simulations such as Geant4,it is usually difficult to describe the non-uniformity of the liquid in a *** propose a method based on geometry description markup language and a tessellated detector description to share the detector geometry information between computational fluid dynamics simulation software and detector simulation *** method makes it possible to study the impact of a liquid flow and non-uniformity on the key performance of a liquid-based detector,such as the event vertex reconstruction *** will also be helpful in the detector design and performance optimization.

关键词： Liquid-based detector Geometry Simulation Geant4 Computational fluid dynamics

Limit Theorems for Critical Galton-Watson Processes with Immigration Stopped at Zero

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Acta Mathematica Sinica,English Series 2024年第2期40卷 435-450页

作者： Dou Dou LI mei zhang Xian yu zhang College of Statistics and Data Science Faculty of ScienceBeijing University of TechnologyBeijing 100124P.R.China Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875P.R.China

In this paper,we consider a critical Galton-Watson branching process with immigration stopped at zero *** precise estimation on the probability generating function of the n-th population are obtained,and the tail prob... 详细信息

关键词： Branching immigration critical life period limit theorems

Contribution of Root Respiration to Total Soil Respiration in a Betula ermanii-Dark Coniferous Forest Ecotone of the Changbai Mountains, China

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Pedosphere 2005年第4期15卷 448-455页

作者： LIU Ying HAN Shi-Jie ZHOU yu-mei zhang Jun-Hui Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 （China）.

Total and root-severed soil respiration rates for five plots set up 50 m apart in a Betula ermanii Cham.-dark coniferous forest ecotone on a north-facing slope of the Changbai Mountains, China, were measured to evaluate the seasonal variations of soil respiration, to assess the effect of soil temperature and water content on soil respiration, and to estimate the relative contributions of root respiration to the total soil respiration. PVC cylinders in each of 5 forest types of a B. ermanii-dark coniferous forest ecotone were used to measure soil respirations both inside and outside of the cylinders. The contribution of roots to the total soil respiration rates ranged from 12.5% to 54.6%. The mean contribution of roots for the different plots varied with the season, increasing from 32.5% on June 26 to 36.6% on August 3 and to 41.8% on October 14. In addition, there existed a significant (P < 0.01) logarithmic relationship between total soil respiration rate and soil temperature at 5 cm soil depth. Also, a similar trend was observed for the soil respiration and soil water content at the surface (0-5 cm) during the same period of time.

关键词： Betula ermanii Cham. dark coniferous forest ecotone root respiration soil respiration

Transformation of Cabbage(Brassica oleracea ***) with Bt cry1Ba3 Gene for Control of Diamondback Moth

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Agricultural Sciences in China 2011年第11期10卷 1693-1700页

作者： YI Deng-xia CUI Lei LIU yu-mei ZHUANG Mu zhang Yang-yong FANG Zhi-yuan YANG Li-mei Key Laboratory of Horticultural Crops Genetic Improvement Ministry of Agriculture~Institute of Vegetables and Flowers Chinese Academyof Agricultural Sciences Beijing 100081 P.R.China

To obtain transgenic cabbage line with broad insect resistance, a new synthetic Bacillus thuringiensis crylBa3 gene was introduced into white cabbage via Agrobacterium tumefaciens-mediated transformation and 37 transformants were obtained. Polymerase chain reaction （PCR） and Southern blot analyses confirmed that crylBa3 was successfully inserted into the genome of cabbage. Reverse transcription-polymerase chain reaction （RT-PCR） demonstrated that crylBa3 was expressed. Western blot results confirmed the production of insecticidal protein encoded by crylBa3. Insect bioassays showed that transgenic cabbages effectively controlled both susceptible and CrylAc-resistant diamondback moth （DBM） larvae.

关键词： Bacillus thuringiensis crylBa3 cabbage diamondback moth resistance

Gastrointestinal discomforts and dietary intake in Chinese urban elders:A cross-sectional study in eight cities of China

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World Journal of Gastroenterology 2019年第45期25卷 6681-6692页

作者： Ai Zhao mei-Chen Wang Ignatius Man-Yau Szeto Li-Ping Meng Yan Wang Ting Li yu-mei zhang School of Public Health Peking UniversityBeijing 100191China Yili Innovation Center Inner Mongolia Yili Industrial Group Co.Ltd.Hohhot 010110Inner Mongolia Autonomous RegionChina Inner Mongolia Dairy Technology Research Institute Co. Ltd.Hohhot 010110Inner Mongolia Autonomous RegionChina

BACKGROUND Gastrointestinal(GI)discomforts are common in the elderly population;however,whether such discomforts are associated with dietary intake has not been *** To evaluate GI discomforts in Chinese urban elders and the associated *** The gastrointestinal symptom rating scale(GSRS)was used to identify GI discomforts in 688 elders from eight cities of *** semi-quantitative food frequency questionnaire and one time of 24 h dietary recall were used to access the food intake,identify dietary pattern,and calculate the nutrients *** About 83%of studied elders experienced at least one of GI discomforts in the past 6 mo;dyspepsia was the most commonly reported(66.7%),followed by reflux(44.8%),abdominal pain(35.9%),constipation(35.8%),and diarrhea(34.7%).Female gender,lower education level,and lower family income were associated with a higher GSRS *** who were diagnosed with a GI-related disease had a higher score of constipation,but a lower score of *** diseases were positively associated with certain GI *** dietary patterns were identified by the method of principal component analysis,which were characterized as high intake of salt and tea;more frequent intake of tubers,fruits,aquatic products,and soybeans;and high intake of cereal,vegetables,and meat,***,no associations between dietary patterns and GSRS score were *** elders with a higher GSRS score had significantly lower intake of bean *** elders whose GSRS score was≥21 and 18-20 decreased their bean production intake by 7.2(0.3,14.3)g/d and 14.3(1.2,27.3)g/d,respectively,compared with those who had a GSRS score≤*** were no differences in other food categories,calories,or nutrients intake among elders with different GSRS *** GI discomforts are common in Chinese urban *** discomforts might be associated with the choice of food.

关键词： Gastrointestinal discomforts Nutrition Dietary intake Nutrients Elderly population