检索结果-南通市图书馆

Enantioselective synthesis of 10-allylanthrones via iridium-catalyzed allylic substitution reaction

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical letters 2016年第5期27卷 619-622页

作者： zheng-le zhao Qing Gu Xin-Yan Wu Shu-Li You Key Laboratory for Advanced Materials and Institute of Fine Chemicals East China University of Science and Technology Shanghai 200237 China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

A highly enantioselective allylic substitution reaction of anthrones with aromatic or aliphatic allyl carbonates was realized by using iridium catalyst prepared from [Ir（COD）CI]2 and BHPphos. Substituted 10-allylanthrones were obtained in excellent yields and with excellent enantioselectivity and regioselectivity （up to 98% yield, 99700 ee） under mild conditions.

关键词： Allylic substitution Anthrone Asymmetric catalysis Enantioselectivity Iridium

通过η~3-苄基钯中间体零价钯催化的吲哚苄基化反应(英文)

在线全文

学校读者我要写书评

暂无评论

催化学报 2015年第1期36卷 15-18页

作者：赵正乐顾庆伍新燕游书力华东理工大学结构可控先进功能材料及其制备教育部重点实验室和精细化工研究所上海200237 中国科学院上海有机化学研究所金属有机国家重点实验室上海200032

本文报道了零价钯催化的吲哚苄基化反应,获得了优秀的区域选择性.使用Pd(PPh3)4作为催化剂,在温和反应条件下,以90%–99%的收率获得含有各类取代吲哚片段的三芳基甲烷化合物.

关键词：苄基化吲哚三芳基甲烷 η3-苄基钯中间体

在线全文

学校读者我要写书评

暂无评论

计算机网络环境下的会计信息化

电脑知识与技术 2012年第5X期8卷 3532-3533页

作者：郑召乐山东省日照市工业学校山东日照276800

随着Internet的迅猛发展,我们迎来了日新月异的电子商务时代,这无疑对传统会计假设会计核算形势传统支付结算方式等产生巨大影响。在计算机网络环境下,在电子商务迅速发展形势下的会计信息化具有无纸化开放性多元化智能性等特点。只有... 详细信息

随着Internet的迅猛发展,我们迎来了日新月异的电子商务时代,这无疑对传统会计假设会计核算形势传统支付结算方式等产生巨大影响。在计算机网络环境下,在电子商务迅速发展形势下的会计信息化具有无纸化开放性多元化智能性等特点。只有建立基于Internet的企业化信息系统,重构企业核心业务流程,实现信息集成,加强企业的运作控制,才能在全球化和网络花的市场竞争中立于不败之地。

关键词：计算机网络会计信息化电子商务

Understanding the local structure and thermophysical behavior of Mg-La liquid alloys via machine learning potential

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 439-449页

作者： Jia zhao Taixi Feng Guimin Lu National Engineering Research Center for Integrated Utilization of Salt Lake Resource East China University of Science and TechnologyShanghai 200237China Joint International Laboratory for Potassium and Lithium Strategic Resources East China University of Science and TechnologyShanghai 200237China

The local structure and thermophysical behavior of Mg-La liquid alloys were in-depth understood using deep potential molecular dynamic(DPMD) simulation driven via machine learning to promote the development of Mg-La alloys. The robustness of the trained deep potential(DP) model was thoroughly evaluated through several aspects, including root-mean-square errors(RMSEs), energy and force data, and structural information comparison results;the results indicate the carefully trained DP model is reliable. The component and temperature dependence of the local structure in the Mg-La liquid alloy was analyzed. The effect of Mg content in the system on the first coordination shell of the atomic pairs is the same as that of temperature. The pre-peak demonstrated in the structure factor indicates the presence of a medium-range ordered structure in the Mg-La liquid alloy, which is particularly pronounced in the 80at% Mg system and disappears at elevated temperatures. The density, self-diffusion coefficient, and shear viscosity for the Mg-La liquid alloy were predicted via DPMD simulation, the evolution patterns with Mg content and temperature were subsequently discussed, and a database was established accordingly. Finally, the mixing enthalpy and elemental activity of the Mg-La liquid alloy at 1200 K were reliably evaluated,which provides new guidance for related studies.

关键词： magnesium-lanthanum liquid alloys local structure macroscopic properties thermodynamic behavior deep potential mo-lecular dynamic simulation

The complex roles of m^(6)A modifications in neural stem cell proliferation, differentiation, and self-renewal and implications for memory and neurodegenerative diseases

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第6期20卷 1582-1598页

作者： Yanxi Li Jing Xue Yuejia Ma Ke Ye Xue zhao Fangliang Ge Feifei zheng Lulu Liu Xu Gao Dayong Wang Qing Xia Department of Biochemistry and Molecular Biology College of Basic Medical SciencesHarbin Medical UniversityHarbinHeilongjiang ProvinceChina College of Basic Medical Sciences Harbin Medical UniversityHarbinHeilongjiang ProvinceChina Basic Medical Institute Heilongjiang Academy of Medical SciencesHarbinHeilongjiang ProvinceChina Key Laboratory of Heilongjiang Province for Genetically Modified Animals Harbin Medical UniversityHarbinHeilongjiang ProvinceChina Translational Medicine Research and Cooperation Center of Northern China Heilongjiang Academy of Medical SciencesHarbinHeilongjiang ProvinceChina Dongzhimen Hospital Beijing University of Chinese MedicineBeijingChina

N6-methyladenosine(m^(6)A), the most prevalent and conserved RNA modification in eukaryotic cells, profoundly influences virtually all aspects of mRNA metabolism. mRNA plays crucial roles in neural stem cell genesis and neural regeneration, where it is highly concentrated and actively involved in these processes. Changes in m^(6)A modification levels and the expression levels of related enzymatic proteins can lead to neurological dysfunction and contribute to the development of neurological diseases. Furthermore, the proliferation and differentiation of neural stem cells, as well as nerve regeneration, are intimately linked to memory function and neurodegenerative diseases. This paper presents a comprehensive review of the roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, as well as its implications in memory and neurodegenerative diseases. m^(6)A has demonstrated divergent effects on the proliferation and differentiation of neural stem cells. These observed contradictions may arise from the time-specific nature of m^(6)A and its differential impact on neural stem cells across various stages of development. Similarly, the diverse effects of m^(6)A on distinct types of memory could be attributed to the involvement of specific brain regions in memory formation and recall. Inconsistencies in m^(6)A levels across different models of neurodegenerative disease, particularly Alzheimer's disease and Parkinson's disease, suggest that these disparities are linked to variations in the affected brain regions. Notably, the opposing changes in m^(6)A levels observed in Parkinson's disease models exposed to manganese compared to normal Parkinson's disease models further underscore the complexity of m^(6)A's role in neurodegenerative processes. The roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, and its implications in memory and neurodegenerative diseases, appear contradictory. These inconsistencies may be a

关键词： Alzheimer's disease cell self-renewal central nervous system memory microglia nerve regeneration neurodegenerative diseases neurogenesis RNA methylation

Unraveling the significance of cobalt on transformation kinetics,crystallography and impact toughness in high-strength steels

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 380-390页

作者： Yishuang Yu Jingxiao zhao Xuelin Wang Hui Guo Zhenjia Xie Chengjia Shang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic *** results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without ***,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to *** improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant ***,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant *** findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.

关键词： high-strength steel cobalt transformation kinetics crystallography impact toughness

Study of thermal decoherence of harmonic oscillators

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第5期42卷 108-114页

作者： LI Jian ZHOU Gao-Liang YAN zheng-Xin LIU Wei WANG zhao-Qi College of Science Xi’an University of Science and TechnologyXi’an 710054China

The thermal decoherence of harmonic oscillators is investigated *** quantum system presented here is a one-dimensional oscillator with angular frequency,which is surrounded by a thermal bath of environmental *** are various environmental oscillators with different angular frequency(below an ultraviolet cutoff).At the beginning,the quantum system is a pure state and the environmental oscillators are in thermodynamic equilibrium with *** a period,the system-environment interactions inspire significant decoherence of the quantum *** decoherence is displayed by explicit calculations of the purity and von Neumann entropy of the quantum *** is worth noting that the decoherence could be significant even in the weak coupling and low temperature case due to the large amount of environmental degrees of *** the decoherence process is inspired between the quantum system and an ordinary thermal environment here,the thermal decoherence result is quite general.

关键词： Quantum decoherence Grand canonical ensemble Oscillators

Identification of Quantitative Trait Locus for Overwintering Germinability in Rice(Oryza sativa L.)

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2012年第11期11卷 1767-1774页

作者： zhao zheng-wu LUO An-cai le Tao LI Shi-gui School of Life Sciences Chongqing Normal University Chongqing 400047 P.R.China Rice Research Institute Sichuan Agricultural University Chengdu 611130 P.R.China

312 recombinant inbred lines （RILs） in F9 from a cross between a overwintering cold-tolerant germplasm resource Glutinous rice 89-1（Gr 89-1） and a cold-sensitive variety Shuhui 527 was used for quantitative trait locus （QTL） analysis. The scores of percent ratooning germinability （PRG） and overwintering germinability （POG） were evaluated. The overwintering germination rate of axillary buds was scored to represent the overwintering germinability. Two significant QTLs （qPRG-4 and qPRG-7） on chromosomes 4 and 7 were detected and explained 8.3 and 7.2% of the total phenotypic variation, respectively. Three significant QTLs （qPOG-2, qPOG-3 and qPOG-7） were identified and mapped on chromosomes 2, 3, and 7, respectively. These QTLs contributed 9.6, 6.7, and 17.8% of phenotypic variations, respectively. A comparative analysis using SSR markers closely linked to the three QTLs for the overwintering revealed cold-tolerant individuals, which harbour the Glutinous rice 89-1 alleles at RM7110, RM250, RM418, and RM232, had a high percent overwintering germinability, while cold-sensitive individuals, which carry Shuhui 527 alleles at these loci, had a low percent overwintering germinability in the F2 population of Shuhui 527/Glutinous rice 89-1. This study demonstrated the utility of these SSR markers for selection of overwintering germinability genotypes.

关键词： rice (Oryza sativa L.) percent overwintering germlnability recombinant inbred lines QTL analysis coldtolerance

Carbonate-activated binder modified by supplementary materials for mine backfill and the associated heavy metal immobilization effects

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2023年第8期30卷 1548-1559页

作者： Xinghang Dai Xiaozhong Gu Jingru zheng Liang zhao le Zhou Haiqiang Jiang School of Civil Engineering Liaoning Petrochemical UniversityFushun 113001China Liaoning Key Lab of Petro-chemical Special Building Materials Fushun 113001China Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang 110819China Changchun Gold Research Institute Co. Ltd.Changchun 130012China

Cemented paste backfill(CPB)is one of the effective methods for resource utilization of tailings,but the high cost of ordinary Portland cement(OPC)limits its *** the poor performance of Na_(2)CO_(3)-activated binders,in this work,supplementary materials,including CaO,MgO,and calcined layered double hydroxide(CLDH),were used to modify their properties with the aim of finding an alternative binder to *** calorimetry,X-ray diffraction,and thermogravimetric analyses were conducted to explore the reaction kinetics and phase assembles of the *** properties of the CPB samples,such as flowability,strength development,and heavy metal immobilization effects,were then *** results show that the coupling utilization of MgO and CLDH showed good *** strength of the Mg_(2)-CLDH_(3) sample was approximately 2.94 MPa after curing for 56 d,which was higher than that of the OPC-based *** the cost of the modified Na_(2)CO_(3)-activated binder was lower than that of the OPC-based *** sample showed satisfactory heavy metal immobilization *** findings demonstrate that carbonate-activated binder modified by supplementary materials can be suitable in CPB.

关键词： tailings cemented paste backfill sodium carbonate environmentally friendly heavy metals