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Mechanisms of melatonin in anti-aging and its regulation effects in radiation-induced premature senescence

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Radiation Medicine and Protection 2021年第1期2卷 33-37页

作者： Liping Ma Qingjie Liu Mei tian xuelei tian Ling Gao Key Laboratory of Radiation Protection and Nuclear Emergency China CDCNational Institute for Radiological ProtectionChinese Center for Disease Control and PreventionBeijing100088China

Melatonin is an effective antioxidant hormone produced mainly by the pineal gland.Premature senescence refers to senescence induced by declined cell proliferation and physiological functions when cells are stimulated by nontelomeric signals.The anti-aging effect of melatonin is exerted by upregulating the expression of silent information regulator 1/Sirtuin 1(SIRT1),which reduces oxidative stress damage,decreases p53 activation,and inhibits the NF-κB pathway.Radiation can induce premature senescence through direct or indirect oxidative stress damage.The mechanism by which melatonin regulates radiation-induced premature senescence includes the inhibition of the p53-mediated senescence pathway through elimination of reactive oxygen species or p53 deacetylation induced by upregulation of SIRT1 expression.Melatonin exhibits different regulatory effects for different cells and types of radiation.

关键词： Melatonin Premature senescence Anti-aging Radiation p53

V-Vo-Co_(3)O_(4)催化剂的制备及其析氧性能的研究

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煤炭转化 2024年第2期47卷 98-108页

作者：郝根彦田露郎学磊钟达忠赵强山西工学院山西朔州036000 太原理工大学化学工程与技术学院太原030024 山西省气体能源高效清洁利用重点实验室太原030024

阳极的析氧反应(OER)是限制电解水制氢的主要因素,传统的OER电催化剂由于活性低、稳定性差等缺点无法实现大规模使用。过渡金属氧化物Co_(3)O_(4)是一种很有前景的OER催化剂,但较弱的导电性仍然制约着其电催化性能。通过对Co_(3)O_(4)... 详细信息

阳极的析氧反应(OER)是限制电解水制氢的主要因素,传统的OER电催化剂由于活性低、稳定性差等缺点无法实现大规模使用。过渡金属氧化物Co_(3)O_(4)是一种很有前景的OER催化剂,但较弱的导电性仍然制约着其电催化性能。通过对Co_(3)O_(4)进行改性以增强电催化活性及稳定性,分别在NaBH4和VCl_(3)水溶液中两步浸泡法合成了富氧空位、V掺杂的Co_(3)O_(4)催化剂。利用XRD、SEM、EDS、TEM、HRTEM、SAED、拉曼光谱、XPS等手段对催化剂的相纯度、晶体结构、微观形貌、含有的官能团及化学键等性质进行测试和分析,并对催化剂进行电化学性能测试。结果表明:氧空位的引入使晶格间距有所增大,V成功掺杂到了Vo-Co_(3)O_(4)/NF(Vo指氧空位)结构中;氧空位和V掺杂协同提高了Co_(3)O_(4)/NF的OER性能。在1 mol/L KOH中,V-Vo-Co_(3)O_(4)/NF仅需253 mV/270 mV的过电位就能驱动50(mA·cm^(-2))/100(mA·cm^(-2))的电流密度,Tafel斜率为71.5 mV/dec,并具有100 h的稳定性。其性能的提升主要归因于V掺杂及氧空位的引入对Co_(3)O_(4)电子构型的调控,低结晶度的表面暴露了更多活性位点,以及亲水性的增强有利于OER过程中反应中间体的吸附和解吸。

关键词：析氧反应(OER) 掺杂氧空位 Co_(3)O_(4) 电解水

The structural change of Cu-Sn melt

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Science China(Physics,Mechanics & Astronomy) 2007年第4期50卷 414-420页

作者： HOU JiXin SUN JianJun ZHAN ChengWei tian xuelei CHEN XiChen Key Laboratory of Liquid Structure and Heredity of Materials of Ministry of Education Shandong UniversityJinan 250061China

With the high-temperature viscometer and magnetic susceptibility measurement device designed by our group,the viscosity and the magnetic susceptibility of the Cu65Sn35 melt were measured during the cooling process.An anomalous change can be found in the curves of viscosity and magnetic susceptibility at a certain temperature.The structure of the melt was studied by the high-temperature X-ray diffractometer.The anomalous change also can be found in the pair distribution function,correlation radius,and coordination number at the approximate tem-perature,which shows the microstructural change of the Cu65Sn35 melt.From the results,it was confirmed that the Cu6Sn5 compound occurs in the melt,which leads to the structural change of the melt.

关键词： Cu-Sn alloy melt structure

Structure correlation of Al_(71.6)Ge_(28.4) eutectic alloy between liquid and solid states

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Chinese Science Bulletin 2010年第15期55卷 761-765页

作者： SUN JianJun tian xuelei ZHAN ChengWei SHI XinYing Key Laboratory of Liquid Structure and Heredity of Materials (Ministry of Education) Shandong University Jinan 250061 China Shandong Labour Vocation and Technology College Jinan 250022 China

The liquid structure of Al71.6 Ge28.4 eutectic alloy was studied by X-ray diffractometer.For the liquid alloy Al71.6 Ge28.4,the structure has no change while the order increases with the decreasing temperature from 1150°C to 550°C.Meanwhile,the correlation between liquid structure and solid structure has also been analyzed by "the nanocrystal model".It is shown that the melt consists of 72.8% α clusters and 27.2% β clusters,but the liquid structure and solid structure have striking difference,which is one of the reasons to obtain a large undercooling easily for this alloy.

关键词：液态结构共晶合金固体结构液体 X射线衍射仪相关性分析液态合金温度降低

Solvothermal-Assisted Exfoliation Process to Produce Graphene with High Yield and High Quality

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Nano Research 2009年第9期2卷 706-712页

作者： Wen Qian Rui Hao Yanglong Hou Yuan tian Chengmin Shen Hongjun Gao xuelei Liang Department of Advanced Materials and Nanotechnology College of EngineeringPeking UniversityBeijing 100871China Institute of Physics Chinese Academy of SciencesBeijing 100190China Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking UniversityBeijing 100871China

Monolayer and bilayer graphene sheets have been produced by a solvothermal-assisted exfoliation process in a highly polar organic solvent,acetonitrile,using expanded graphite(EG)as the starting material.It is proposed that the dipole-induced dipole interactions between graphene and acetonitrile facilitate the exfoliation and dispersion of graphene.The facile and effective solvothermal-assisted exfoliation process raises the low yield of graphene reported in previous syntheses to 10 wt%12 wt%.By means of centrifugation at 2000 rpm for 90 min,monolayer and bilayer graphene were separated effectively without the need to add a stabilizer or modifi er.Electron diffraction and Raman spectroscopy indicate that the resulting graphene sheets are high quality products without any signifi cant structural defects.

关键词： Graphene solvothermal-assisted exfoliation monolayer and bilayer high quality

A novel Al-10Si-2Fe master alloy and its ef ect on inoculation of eutectic cells in Sr-modii ed A356 alloy

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China Foundry 2014年第2期11卷 98-102页

作者： Zhang Yong Zheng Hongliang Liu Yue Shi Lei Xu Rongfu tian xuelei Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong University Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong University

To investigate the possibility of inoculating eutectic cells, a novel Al-10Si-2Fe master alloy was synthesized and tested in Sr-modifi ed A356 alloy. The new master alloy that consists of α-Al, Si and β-Al5FeSi phases was prepared by a casting process, and the silicon phase was found to grow epitaxially from the β-Al5FeSi particles. The inoculation effi ciency of the new master alloy on Sr-modifi ed A356 alloy has been investigated by quenching experiment and thermal analysis. With the addition of the new master alloy, the area density of eutectic cells is effectively increased by 100% and the eutectic growth temperature is increased by 1.5 oC. Therefore, the new master alloy is deduced to introduce nucleating substrates for eutectic cells and to refi ne the eutectic cells in Sr-modifi ed A356 alloy. There is no poisonous interaction between the Al-10Si-2Fe master alloy and the Sr in this study. Consequently, the mechanical properties have been improved by the addition of the new master alloy.

关键词： aluminum alloys eutectic cells inoculation mechanical properties

Correlation between Structures of Bulk Amorphous Zr-Ti-Ni-Cu-Be Alloy in Different States

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Journal of Materials Science & Technology 2001年第1期17卷 93-94页

作者： xuelei tian and Xichen CHEN Institute of Mater. Sci. & Eng., Shandong University of Technology, Jinan 250061, China Inst. of Mater. Sci. Shandong Univ. of Technol. Jinan 250061 China

The structures of the bulk amorphous Zr41Ti14Cu12.5Nil0.0Be22.5 alloy have been analyzed in solid, supercooled liquid and liquid with X-ray diffraction. The first coordination sphere radii and the first coordination numbers are 0.312 um, 11.2 in solid state.10.932 nm, 10.932 in supercooled liquid region and 0.305 urn, 11.296 in liquid state. The structures are the same in different states. But it shows some tendency to crystallizing that the first coordination sphere radius and the first coordination number drop in supercooled liquid region.

关键词： Ti Zr Correlation between Structures of Bulk Amorphous Zr-Ti-Ni-Cu-Be Alloy in Different States Cu

Chromosome-Level Reference Genome and Population Genomic Analysis Provide Insights into the Evolution and Improvement of Domesticated Mulberry (Morns alba)

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Molecular Plant 2020年第7期13卷 1001-1012页

作者： Feng Jiao Rongsong Luo xuelei Dai Hui Liu Gang Yu Shuhua Han Xin Lu Chao Su Qi Chen Qinxia Song Caiting Meng Fanghong Li Hongmei Sun Rui Zhang tian Hui Yonghua Qian Aichun Zhao Yu Jiang The Sericultural and Silk Research Institute College of Animal Science and TechnologyNorthwest A&F UniversityYangling 712100China Key Laboratory of Animal Genetics Breeding and Reproduction of Shaanxi ProvinceCollege of Animal Science and TechnologyNorthwest A&F UniversityYangling 712100China State Key Laboratory of Silkworm Genome Biology Institute of Sericulture and Systems BiologySouthwest UniversityChong Qing 400716China State Key Laboratory of Reproductive Regulation&Breeding of Grassland Livestock Inner Mongolia UniversityHohhot 010070China

Mulberry(Morns spp.)is the sole plant consumed by the domesticated silkworm.However,the genome of domesticated mulberry has not yet been sequenced,and the ploidy level of this species remains unclear.Here,we report a high-quality,chromosome-level domesticated mulberry(Morus alba)genome.Analysis of genomic data and karyotype analyses confirmed that M.alba is a diploid with 28 chromosomes(2/7=2x=28).Population genomic analysis based on resequencing of 134 mulberry accessions classified domesticated mulberry into three geographical groups,namely,Taihu Basin of southeastern China(Hu mulberry),northern and southwestern China,and Japan.Hu mulberry had the lowest nucleotide diversity among these accessions and demonstrated obvious signatures of selection associated with environmental adaptation.Further phylogenetic analysis supports a previous proposal that multiple domesticated mulberry accessions previously classified as different species actually belong to one species.This study expands our understanding of genome evolution of the genus Morus and population structure of domesticated mulberry,which would facilitate mulberry breeding and improvement.

关键词： domesticated mulberry de novo assembly population genomics comparative genomics sericulture environment adaption

Effects of Cooling Rate on High-temperature Mechanical Properties of A356 Alloys

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稀有金属材料与工程 2011年第S3期40卷 63-68页

作者： Zhang Kai, Sun Yucheng, Wang Suolin, Zheng Hongliang, Xu Rongfu, tian xuelei Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China Shandong Univ Key Lab Liquid Solid Struct Evolut & Proc Mat Minist Educ Jinan 250061 Peoples R China

High temperature mechanical properties of A356 alloy castings under different solidification cooling rates have been studied and the influence of cooling rates on secondary dendrite arm spacing (SDAS) and mechanical properties has been discussed. To get different cooling rates, three different types of mold—green sand, green sand with chill and permanent mold, were used to pour castings which would subsequently be machined into tensile test and metallographic specimens. The temperature curves of castings’ solidification in three different mold were recorded using thermal couples, which would be used to calculate their corresponding cooling rates. Tensile tests were carried out at 20, 200, 300, 400 and 500 ℃ and then mechanical properties, such as tensile strength, yield strength, elongation, of specimens from different mold types at different test temperatures were obtained. And SDAS of different specimens were measured using optical metallographic photos. From integrated analysis of all those results, following conclusions could be reached. The relationship between SDAS and cooling rates is negative, and the quantitative relationship has been obtained through data fitting analyzing. Generally speaking, tensile strength and yield strength decease as the temperature elevates while elongation behaves in the contrary trend. Through the regression analysis of SDAS, mechanical properties and temperature, the relationship among them is obtained, which makes quantitative prediction of A356 alloy’s mechanical properties at different temperatures with different solidification cooling rates be possible.

关键词： A356 alloy high temperature mechanical properties cooling rate SDAS