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Effect of martensitic transformation on nano/ultrafine-grained structure in 304 austenitic stainless steel

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Journal of Iron and Steel Research International 2017年第12期24卷 1231-1237页

作者： Na Gong hui-bin Wu Gang niu Jia-ming Cao Da Zhang Tana Instituted Engineering Technology University of Science and Technology BeijingBeiking 100083China Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China Sinohydro Renewable Energy Co. Ltd.Beijing 100083China

304 austenitic stainless steel was cold rolled in the range of 20%-80%reductions and then annealed at 700-900°C for 60 sto obtain nano/ultrafine-grained（NG/UFG）*** electron microscopy,electron backscatter diffraction and X-ray diffraction were used to characterize the resulting *** results showed that with the increase of cold reduction,the content of martensite was *** steel performed work hardening during cold-working owing to the occurrence of strain induced martensite which nucleated in single shear *** rolling broke up the lath-type martensite into dislocation-cell type martensite because of the formation of slip *** annealed at 800-960°C for 60 swere of NG/UFG structure with different percentage of nanocrystalline（60-100 nm）and ultrafine（100-500 nm）grains,submicron size（500-1000 nm）grains and micron size（〉1000 nm）*** value of the Gibbs free energy exhibited that the reversion mechanism of the reversion process was shear controlled by the annealing *** a certain annealing time during the reversion process,austenite nucleated first on dislocation-cell type martensite and the grains grew up subsequently and eventually to be micrometer/submicrometer grains,while the nucleation of austenite on lath-type martensite occurred later resulting in nanocrystalline/ultrafine *** existence of the NG/UFG structure led to a higher strength and toughness during tensile test.

关键词： 304 austenitic stainless steel Nano/ultrafine-grained structure Reversion mechanism Lath-type martensite Dislocation-cell type martensite Martensitic transformation

Structures and Properties of La_(0.8)Sr_(0.2)MnO_(3+σ)^(-z) SBA-15(z=0, 1, 2, 4) Perovskite Catalysts

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Journal of Wuhan University of Technology(Materials Science) 2018年第1期33卷 23-29页

作者：黄学辉 niu Pengju LI Ming LIAO hui SHANG xiaohui School of Materials Science and Engineering Wuhan University of Technology

Mesoporous La0.8Sr0.2MnO3＋σ/z SBA-15（z = 1, 2, 4） perovskite oxides were synthesized via hard-templating with ordered mesoporous silica SBA-15 as the template. The as-prepared samples were characterized by XRD, SEM, AFM, BET, and XPS and the catalytic activity was tested for CO oxidation. The wide-angle XRD patterns showed that La0.8Sr0.2MnO3＋σ perovskite was formed. The SEM and AFM analyses exhibited that La0.8Sr0.2MnO3＋σ by hard-templating method had much smaller particle size（18 nm） than that（40 nm） by the sol-gel method. The perovskite-type oxides La0.8Sr0.2MnO3＋σ/z SBA-15（z = 1, 2, 4） also displayed a higher BET surface area from 70 to 143.7 m^2/g and a disordered mesostructure from nitrogen sorption analysis, as well as a small-angle XRD pattern. Moreover, the La0.8Sr0.2MnO3＋σ/z SBA-15（z = 1, 2, 4） perovskite exhibited a much higher activity in CO oxidation than the conventional La0.8Sr0.2MnO3＋σ perovskite. Further analysis by the means of XPS techniques indicated that the existence of high content of Oads/Olatt species contributed to the high activity.

关键词： hard-templating sol-gel perovskite catalyst mesoporous structure CO oxidation

Inhibitory Effects of 1-MCP and DPA on Superficial Scald of Dangshansuli Pear

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Agricultural Sciences in China 2011年第10期10卷 1638-1645页

作者： hui Wei niu Rui-xue SONG Yao-qiang LI De-ying College of Life Sciences Shaanxi Normal University Xi＇an 710062 P.R.China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 P.R.China Biological Sciences Department Qinghai University Xining 810061 P.R. China

Dangshansuli pear is one of crisp pears and has a non-climacteric respiratory pattern. Dangshansuli pear fruits were treated with 1 000 or 2 000 μL L-1 diphenylamine （DPA） for 1 min, or with 0.5 μL L-1 1-methylcyclopropene （l-MCP） for 12 h before cold storage at （2±0.5）℃ for up to 210 d. Incidences of superficial scald and related physiological indexes were investigated during storage. The results showed that superficial scald occurred in control fruit with a rate of over 90% after 210 d at cold storage plus 10 d at room temperature. Treatments with 1 000 and 2 000 μL L-1 DPA and 0.5 μL L-1 l-MCP inhibited the accumulation of a-farnesene, conjugated trienes, total phenolic contents, and malondialdehyde （MDA） during storage. The treatments also decreased leakage of cell membrane and the activity of polyphenol oxidase （PPO） in the peel. These results indicate that 1-MCP and DPA treatments inhibit and postpone the occurrence of superficial scald of Dangshansuli pears remarkably in cold storage and post-storage shelf life, respectively, while the mechanisms were different. The results above may provide a theoretical evidence for the agriculture production.

关键词： 1-MCP diphenylamine pear superficial scald

Nuclear dynamics in multinucleon transfer reactions near Coulomb barrier energies

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Nuclear Science and Techniques 2018年第12期29卷 128-133页

作者： Peng-hui Chen Fei niu Ya-Fei Guo Zhao-Qing Feng Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000 China University of Chinese Academy of Sciences Beijing 100190China South China University of Technology Guangzhou 510641China

The mechanism of multinucleon transfer reactions has been investigated within the dinuclear system model, in which the sequential nucleon transfer is described by solving a set of microscopically derived master equations. The transfer dynamics in the reaction of^(136)Xe+^(208)Pb near Coulomb barrier energies is thoroughly analyzed. It is found that the total kinetic energies of primary fragments are dissipated from the relative motion energy of two touching nuclei and exhibit a symmetric distribution along the fragment mass. The angular distribution of the projectile-like fragments moves forward with increasing beam energy. However, the target-like fragments exhibit an opposite trend. The shell effect is pronounced due to the fragment yields in multinucleon transfer reactions.

关键词：原子动力学转移反应精力库仑相对运动显微镜子转移原子核

Exploring the tidal effect of urban business district with large-scale human mobility data

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Frontiers of Computer Science 2023年第3期17卷 77-90页

作者： Hongting niu Ying SUN Hengshu ZHU Cong GENG Jiuchun YANG hui XIONG Bo LANG School of Computer Science and Engineering Beihang UniversityBeijing 100191China Key Lab of Intelligent Information Processing of Chinese Academy of Sciences(CAS) Institute of Computing TechnologyCASBeijing 100086China Baidu Talent Intelligence Center Baidu Inc.Beijing 100085China Business School Imperial College LondonLondon SW72AZUK Artificial Intelligence Thrust The Hong Kong University of Science and TechnologyGuangzhou 510030China

Business districts are urban areas that have various functions for gathering people,such as work,consumption,leisure and *** to the dynamic nature of business activities,there exists significant tidal effect on the boundary and functionality of business ***,effectively analyzing the tidal patterns of business districts can benefit the economic and social development of a ***,with the implicit and complex nature of business district evolution,it is non-trivial for existing works to support the fine-grained and timely analysis on the tidal effect of business *** this end,we propose a data-driven and multi-dimensional framework for dynamic business district ***,we use the large-scale human trajectory data in urban areas to dynamically detect and forecast the boundary changes of business districts in different time ***,we detect and forecast the functional changes in business *** results on real-world trajectory data clearly demonstrate the effectiveness of our framework on detecting and predicting the boundary and functionality change of business ***,the analysis on practical business districts shows that our method can discover meaningful patterns and provide interesting insights into the dynamics of business *** example,the major functions of business districts will significantly change in different time periods in a day and the rate and magnitude of boundaries varies with the functional distribution of business districts.

关键词： business district trajectory functionality detection tidal effect boundary detection visiting score

Selective and stable elimination of endosymbionts from multiple-infected whitefly Bemisia tabaci by feeding on a cotton plant cultured in antibiotic solutions

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Insect Science 2020年第5期27卷 964-974页

作者： Dong-xiao Zhao Zhi-Chun Zhang Hong-Tao niu hui-Fang Guo Institute of Plant Protection Jiangsu Academy of Agricultural SciencesNanjingChina

The maternally heritable endosymbiont provides many ecosystem *** elimination of a specific symbiont and establishment of experimental host lines lacking certain symbionts enable the roles of a given symbiont to be *** whitefly Bemisia tabaci(Gennadius)in China harbors obligate symbiont Portiera infecting each in-dividual,as well as facultative symbionts,such as Hamiltonella,Rickettsia and Cardinium,with co-infections occurring relatively *** far no studies have evaluated the selectivity and efficacy of a specific symbiont elimination using antibiotics in whiteflies co-infected with different ***,no success has been achieved in estab-lishing certain symbiont-free *** *** this study,we treated Hamiltonella infected *** line,Hamiltonella-Rickettsia-co infected line and Hamiltonella-Cardinium co-infected line by feeding *** adults with cotton plants cultured in water containing ri-fampicin,ampicillin or a mixture of them,aiming to selectively curing symbiont infections and establishing stable symbiont-free *** found ampicillin selectively eliminated Cardinium without afecting Portiera,Hamiltonella and Rickettsia,although they coex-isted in the same host ***,all of the symbionts considered in our study can be removed by *** reduction of facultative symbionts occurred at a much quicker pace than obligate symbiont Portiera during rifampicin ***,we measured the stability of symbiont elimination in whitefly successive generations and established Rickettsia-infected and Cardinium-infected lines which are absent in natural *** results provide new protocols for selective elimination of symbionts co-existing in a host and establishment of different symbiont-infected host lines.

关键词： antibiotic treatment Bemisia tabaci co-infections endosymbionts infection frequency

Metabolic profiling of DREB-overexpressing transgenic wheat seeds by liquid chromatographymass spectrometry

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The Crop Journal 2020年第6期8卷 1025-1036页

作者： Fengjuan niu Qiyan Jiang xianjun Sun Zheng Hu Lixia Wang hui Zhang Institute of Crop Sciences National Key Facility for Crop Gene Resources and Genetic ImprovementChinese Academy of Agricultural SciencesBeijing 100081China

DREBs are transcription factors that regulate abiotic stress tolerance in ***,we reported that wheat transgenic lines overexpressing Gm DREB1 showed increased tolerance to drought and salt ***,the molecular basis of increased tolerance is still poorly understood,and whether the overexpression of DREB will cause unexpected effects is also of *** performed seed metabolic profiling of the genetically modified(GM)wheat T349 and three non-GM cultivars with LC-MS to identify the metabolic basis of stress tolerance and to assess the unexpected effects of exogenous gene *** we did not note the appearance of novel metabolites or the disappearance of existing metabolites,overexpression of the transcription factor Gm DREB1 in T349 wheat influenced metabolite levels in *** levels of stress tolerance-associated metabolites were found in the stress-sensitive non-transgenic acceptor counterpart J19,while metabolites associated with cell membrane structure and stability accumulated in *** these metabolites in T349,most showed levels similar to those in the non-GM *** of Gm DREB1 in T349 may cause a shift in its metabolic profile leading to down-regulation of several energy-consuming processes to favor increased yield under stress conditions,which is a reasonable expectation of breeders while creating the GM wheat and Gm DREB1 overexpression did not cause unexpected effects in T349 *** results may be helpful for GM crop research and risk assessment.

关键词： Transgenic wheat Metabolomics LC-MS DREB Drought tolerance

Recent advances in CRISPR research

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Protein & Cell 2020年第11期11卷 786-791页

作者： Baohui Chen Yuyu niu Haoyi Wang Kejian Wang hui Yang Wei Li Department of Cell Biology and Bone Marrow Transplantation Center of the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310058China Yunnan Key Laboratory of Primate Biomedical Research Institute of Primate Translational MedicineKunming University of Science and TechnologyKunming 650500China State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China State Key Laboratory of Rice Biology China National Rice Research InstituteChinese Academy of Agricultural SciencesHangzhou 310006China Institute of Neuroscience State Key Laboratory of NeuroscienceKey Laboratory of Primate NeurobiologyCAS Center for Excellence in Brain Science and Intelligence TechnologyShanghai Research Center for Brain Science and Brain-Inspired IntelligenceShanghai Institutes for Biological SciencesChinese Academy of SciencesShanghai 200031China

The clustered regularly interspaced short palindromic repeats(CRISPR)technology has revolutionized life sciences and developed ***,we highlight the recent advances in development and application of CRISPR technologies,including the discovery of novel CRISPR systems,CRISPR base editing and imaging,and the applications of CRISPR in plant breeding,animal breeding,disease modeling and biotherapy.

关键词： CRISPR breeding advances

Could extracellular vesicles derived from mesenchymal stem cells be a potential therapy for acute pancreatitis-induced cardiac injury?

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World Journal of Stem Cells 2023年第7期15卷 654-664页

作者： Long-Fei Pan Ze-Qun niu Song Ren Hong-Hong Pei Yan-xia Gao hui Feng Jiang-Li Sun Zheng-Liang Zhang Emergency Department The Second Affiliated Hospital of Xi'an Jiaotong UniversityXi’an 710004Shaanxi ProvinceChina Department of Geriatric Digestive Surgery The Second Affiliated Hospital of Xi'an Jiaotong UniversityXi’an 710004Shaanxi ProvinceChina

Acute pancreatitis(AP)often leads to a high incidence of cardiac injury,posing significant challenges in the treatment of severe AP and contributing to increased mortality *** stem cells(MSCs)release bioactive molecules that participate in various inflammatory ***,extracellular vesicles(EVs)secreted by MSCs have garnered extensive attention due to their comparable anti-inflammatory effects to MSCs and their potential to avoid risks associated with cell ***,the therapeutic potential of MSCs-EVs in various inflammatory diseases,including sepsis and AP,has gained increasing *** preclinical research on the utilization of MSCs-EVs in AP-induced cardiac injury is limited,several studies have demonstrated the positive effects of MSCs-EVs in regulating inflammation and immunity in sepsis-induced cardiac injury and cardiovascular ***,clinical studies have been conducted on the therapeutic application of MSCs-EVs for some other diseases,wherein the contents of these EVs could be deliberately modified through prior modulation of ***,we hypothesize that MSCs-EVs hold promise as a potential therapy for AP-induced cardiac *** paper aims to discuss this ***,additional research is essential to comprehensively elucidate the underlying mechanisms of MSCs-EVs in treating AP-induced cardiac injury,as well as to ascertain their safety and efficacy.

关键词： Acute pancreatitis Cardiac injury Mesenchymal stem cells Extracellular vesicles Inflammation Therapeutic strategies