检索结果-南通市图书馆

A Classification of Finite Metahamiltonian p-Groups

在线全文

学校读者我要写书评

暂无评论

Communications in Mathematics and Statistics 2021年第2期9卷 239-260页

作者： Xingui Fang lijian An School of Mathematics Science Peking UniversityBeijing 100087People’s Republic of China Department of Mathematics Shanxi Normal UniversityLinfen 041004ShanxiPeople’s Republic of China

A finite non-abelian group G is called metahamiltonian if every subgroup of G is either abelian or normal in *** G is non-nilpotent,then the structure of G has been *** G is nilpotent,then the structure of G is determined by the structure of its Sylow ***,the classification of finite metahamiltonian p-groups is an unsolved *** this paper,finite metahamiltonian p-groups are completely classified up to isomorphism.

关键词： Minimal non-abelian groups Hamiltonian groups Metahamiltonian groups A_(2)-groups

Finite p-groups with a minimal non-abelian subgroup of index p(Ⅲ)

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

Science China Mathematics 2015年第4期58卷 763-780页

作者： QU HaiPeng XU MingYao AN lijian School of Mathematics and Computation Science Shanxi Normal University

This paper finishes the classification of three-generator finite p-groups G such that Φ(G) Z(G).This paper is a part of classification of finite p-groups with a minimal non-abelian subgroup of index p, and partly sol... 详细信息

关键词： characteristic matrix At-groups congruent sub-congruent quasi-congruent

Microstructure and Mechanical Properties of 06Cr13Ni4Mo Steel Treated by Quenching–Tempering–Partitioning Process

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2016年第2期32卷 189-193页

作者： Yuanyuan Song Jingping Cui lijian Rong Institute of Metal Research Chinese Academy of Sciences Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences

A heat treatment process, quenching-tempering-partitioning （Q-T-P）, has been applied to a low carbon martensitic stainless steel 06Crl3Ni4Mo. By using this process, ultrafine reversed austenite can be obtained at room temperature. The microstructures of the reversed austenite and the martensite matrix were characterized by transmission electron microscopy （TEM） and energy dispersive spectroscopy （EDS） in detail. The results show that the ultrafine reversed austenite is enriched in Ni resulting in the austenite stability at room temperature. Two new types of nano-scale carbide precipitates are found in the martensite matrix. Detailed analysis suggests that the two nano-scale precipitates can be identified as ω phase and λ phase carbides, respectively. The orientation relationship between the ω phase and matrix is [011]α [/[2110]ω and （211）α//（0110）ω, while that between the X phase precipitate and matrix is [011]α][[0001]λ and （200）α/（1210）λ. For the present steel, the ultrafine reversed austenite and carbide precipitates obtained by Q-T-P treatment provide a good combination of high strength and toughness.

关键词： Quenching-tempering-partitioning Martensitic stainless steel Microstructure Reversed austenite Carbide precipitates

Residue analysis and dissipation of a new fungicide 2-allylphenol in tomato

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2005年第3期17卷 491-493页

作者： HUJi-ye ZHANGWen-ji lijian-zhong ResearchCenterforEeo-EvironmentalSciences ChineseAcademyofSciencesBeijing100085.China ScienceCollege ChinaAgriculturalUniversity.Beijiug100094China

The method of residue analysis of a new synthesized fungicide 2-allylphenol was studied by simulating the active compound structure in Gingko tree(Gingko biloba L.) and its dissipation rate and terminal residue levels in tomato under field condition. Residues of 2-allylphenol were extracted from tomato matrix with acetone, purified by liquid-liquid extraction and Florisil cartrieges, and then determined by HPLC with UV-detector. The minimum detectable amount of 2-allylphenol was 3×10 -9 g, the minimum detectable concentration of 2-allylphenol in the samples of tomato were 0.01 mg/kg. The ranges of average recoveries and coefficient variation of the method were 87.7%—90.2% and 1.25%—2.06%, respectively. The dissipation rate and terminal residue levels in tomato were determined with the method described above. The results showed that the half-life of 2-allylphenol in tomato was 6.37 d, and 2-allylphenol declined with 82.6% of the initial deposit remaining in tomato at harvest. The terminal residue levels in tomato were 0.15 mg/kg and 0.20 mg/kg following the recommended doses and time intervals.

关键词： fungicide 2-allylphenol residue analysis dissipation

Syntheses of Tetrahydropyrrolizino[2,1-c]quinoline Derivatives

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2005年第4期21卷 460-462页

作者： SONGHong-rui WANGFei lijian ZHANGShou-fang SchoolofPharmaceuticalEngineering ShenyangPharmaceuticalUniversityShenyang110016P.R.China

The three title compounds were prepared from 2-phenylaminomethyl-3H-1,2-dihydro-1-pyrrolizinols via an intramolecular Friedel-Crafts reaction. 2-Phenylaminomethyl-3H-1,2-dihydro-1-pyrrolizinols were prepared from 2-phenylaminomethyl-3H-1,2-dihydro-1-pyrrolizinones via reduction. The heterocyclic ring system of pyrrolizino[2,1-c]quinoline has not been found in literature.

关键词： Pyrrolizino[2,1-c]quinoline Synthesis Heterocycles

1990-2019年全球宫颈癌疾病负担分析

在线全文

学校读者我要写书评

暂无评论

中华肿瘤防治杂志 2024年第4期31卷 210-215页

作者：卫飞雪冯瑞梅高雪丁玲雷立健王彤山西医科大学公共卫生学院流行病学与卫生统计学教研室煤炭环境致病与防治教育部重点实验室山西太原030001

目的通过分析全球、各区域和不同国家近30年宫颈癌疾病负担的变化趋势,以识别在消除宫颈癌方面取得进展的国家以及需要进一步努力的国家和地区,从而为实现世界卫生组织(WHO)提出的消除宫颈癌的全球目标提供借鉴。方法采用线性回归模... 详细信息

目的通过分析全球、各区域和不同国家近30年宫颈癌疾病负担的变化趋势,以识别在消除宫颈癌方面取得进展的国家以及需要进一步努力的国家和地区,从而为实现世界卫生组织(WHO)提出的消除宫颈癌的全球目标提供借鉴。方法采用线性回归模型分析全球疾病负担2019数据库中1990-2019年全球、6个WHO分区以及204个国家宫颈癌发病、死亡及伤残调整生命年(DALY)的时间变化趋势。结果全球宫颈癌新发病例数从1990年的335 642例增长至2019年的565 541例,年增长率为2.3%,死亡病例数从184 527例增长至280 479例,年增长率为1.7%。1990-2019年全球和除西太平洋地区以外的WHO区域宫颈癌年龄标化发病率、标化死亡率和标化DALY率均呈降低趋势,年降低率为0.1%~1.2%。在204个国家中,过去30年有43个国家宫颈癌标化发病率和20个国家宫颈癌标化死亡率呈增长趋势,这些国家主要集中在非洲地区,尤其是撒哈拉以南地区。结论全球宫颈癌绝对负担的增加以及在非洲等部分国家标化发病率和死亡率的增加提示亟需在这些地区制定和实施相关政策,以提高疫苗接种率、宫颈癌筛查覆盖率以及宫颈病变的治疗率,从而尽快实现在全球范围内消除宫颈癌这一宏伟目标。

关键词：宫颈癌发病死亡伤残调整生命年时间趋势分析

Microstructure and Mechanical Properties of Electron Beam Welded Alloy J75

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2014年第5期30卷 493-498页

作者： Shenghu Chen Mingjiu Zhao Hao Liang lijian Rong Institute of Metal Research Chinese Academy of Sciences Institute of System Engineering China Academy of Engineering and Physics

Microstructure and mechanical properties of electron beam post-weld aging treatment （PWAT） conditions. The results welded alloy J75 were studied under as-welded and showed that high-quality welds were produced by electron beam welding. Under as-welded condition, a fine dendritic structure consisting of gamma dendrite matrix and Laves phase was observed in the welds. Better mechanical properties were obtained in the weld zone than that of base metal because of the fine size of the dendritic structure. After PWAT, a discontinuous distribution of γ＇ particles existed in the dendritic structure. The presence of a γ＇ depletion zone in the dendrite core resulted in a significant degradation of mechanical properties of the weld.

关键词： Electron beam welding Alloy J75 Precipitation Mechanical properties

Overview of hydrogen-resistant alloys for high-pressure hydrogen environment:on the hydrogen energy structural materials

在线全文

学校读者我要写书评

暂无评论

Clean Energy 2023年第1期7卷 99-115页

作者： Jiaxing Liu Mingjiu Zhao lijian Rong Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

With the progressive expansion of hydrogen fuel demand,hydrogen pipelines,hydrogen storage cylinders and hydrogen refuelling stations(HRSs)are the primary components of hydrogen energy systems that face high-pressure hydrogen *** embrittlement(HE)is a typical phenomenon in metallic materials,particularly in the high-pressure hydrogen environment,that causes loss of ductility and potentially catastrophic *** is associated with materials,the service environment and *** primary mechanisms for explaining the HE of materials are hydrogen-enhanced decohesion,hydrogen-induced phase transformation,hydrogen-enhanced local plasticity,adsorption-induced dislocation emission and hydrogen-enhanced strain-induced *** reduce the risk of HE for metallic structural materials used in hydrogen energy systems,it is crucial to reasonably select hydrogen-resistant materials for high-pressure hydrogen *** paper summarizes HE phenomena,mechanisms and current problems for the metallic structural materials of hydrogen energy systems.A research perspective is also proposed,mainly focusing on metal structural materials for hydrogen pipelines,hydrogen storage cylinders and hydrogen compressors in HRSs from an application perspective.

关键词： hydrogen energy hydrogen refuelling station hydrogen pipelines hydrogen storage cylinder hydrogen embrittlement hydrogen embrittlement mechanism

Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex:[NdFe(CN)_6(DMF)_4(H_2O)_3]H_2O

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

Chinese Journal of Structural Chemistry 2003年第2期22卷 182-186页

作者： lijian－Rong BUXian－He 等 StateKeyLaboratoryofStructuralChemistry FujianInsttituteofResearchonTheStructureofMantterTheChineseAcademyofSciencesFuzhouFujian350002China DepartmentofChemistry NankaiUniver

A new bimetallic cyano-bridged complex, [NdFe(CN)6(DMF)4(H2O)3]H2O (DMF = N,N-dimethylformamide) 1, has been obtained by the reaction of hexacyanoferrate potassium with neodymium (Ⅲ) chloride in H2O/EtOH/DMF (volume ratio: 2:2:1), and its structure was determined by means of single-crystal X-ray diffraction. The compound crystallizes in space group P21/n of monoclinic system with cell parameters: a = 17.646(1), b = 8.9011(3), c = 19.945(1) ? b = 95.835(2)? V = 3116.6(3) ?, Z = 4, Dc = 1.536 g/cm3, Mr = 720.66, F(000) = 1456, m = 2.166 mm-1, R = 0.0386, wR = 0.1120 and S = 1.061. The central Nd (Ⅲ) ion is coordinated by seven oxygen atoms of four DMF molecules and three water molecules and one nitrogen atom of the bridging cyanide in a slightly distorted square-antiprism arrangement, and the Fe (Ⅲ) ion is in an almost octahedral environment coordinated to six cyano-ligands, of which one cyanide ligand bridges the Nd (Ⅲ) ion to form a bimetallic complex. Molecules of complexes in the crystal lattice are held together by hydrogen bonding, forming a three-dimensional framework.

关键词： crystal structure cyano-bridged bimetallic complex neodymium (Ⅲ) complex ion (Ⅲ) complex