检索结果-南通市图书馆

Enantioselective Resolution of (±)-l-Phenylethyl Acetate by Using the Whole Cells of Deep-sea Bacterium Bacillus sp. DL-2

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

Chemical Research in Chinese Universities 2019年第5期35卷 792-798页

作者： DONG Lu XU Yongkai ZHANG Yun SUN Aijun HU Yunfeng CAS Key Laboratory of Tropical Marine Bio-resources and Ecology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301P.R.China University of Chinese Academy of Sciences Beijing 100049P.R.China Guangdong Key Laboratory of Marine Materia Medica South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301P.R.China Affiliated Hospital of Shandong University of Traditional Chinese Medicine Jinan 250014P.R.China

Bacillus sp. DL-2 was isolated from the deep sea of the Western Pacific and further utilized as novel biocatalysts to efficiently asymmetrically hydrolyze (±)-1-phenylethyl acetate. After the optimization of hydrolytic reactions, chiral chemicals (R)1-phenylethanol and (S)-l-phenylethyl acetate were obtained with high optical purities (96% and 99.8%, respectively). Our research is about the asymmeric hydrolysis of (±)-1-phenylethyl acetate using whole-cell biocatalysts. In addition, the optical purity of (S)-l-phenylethyl acetate generated through the kinetic resolution of (±)-1-phenylethyl acetate using the whole-cells of Bacillus sp. DL-2 was the highest report so far. Using the whole cells of deep sea bacterium Bacillus sp. DL-2 as the biocatalysts is an enviromnentally friendly method and will play critical roles in industrial asymmetric synthesis.

关键词： Deep-sea microorganism Whole-cell biocatalyst asymmetric hydrolysis (R)-1-Phenylethanol (S)-1-Phenylethyl acetate

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

中国财政周期波动的非对称性特征研究

财政与税务 2014年第7期 11-18页

作者：孙晓娟

财政收入和支出是宏观经济生活中的重要指标。随着中国基本建设投入力度的不断加大，财政收支的周期性波动对国民经济产生了越来越重要的影响。运用HP滤波、BK模型和二阶导数法三种分析工具，对中国的财政收支的非对称性特征进行检验。... 详细信息

财政收入和支出是宏观经济生活中的重要指标。随着中国基本建设投入力度的不断加大，财政收支的周期性波动对国民经济产生了越来越重要的影响。运用HP滤波、BK模型和二阶导数法三种分析工具，对中国的财政收支的非对称性特征进行检验。结果显示，中国的财政波动呈现出陡升缓降、扩张深度型和扩张尖度型相结合的非对称性特征。据此，可以给出相应的政策含义。

关键词：财政波动非对称性 HP滤波 BK模型二阶导数 financial fluctuation asymmetric HP filter BK model two order derivative

来源：人大复印报刊资料评论

在线全文

人大复印报刊资料

学校读者我要写书评

暂无评论

电波传播与天线

电子科技文摘 2003年第9期 45-46页

Y2002-63392-317 0319915非对称耦合硅线接地面实验研究=Expenmental sludyof the ground plane in asymmetric coupled sillcon lines[会,英]/Arz.u.& Williams,D.F.//2001 IEEE10th Topial Meeting on Electrical Performance of Elec... 详细信息

关键词：电波传播地面实验非对称 asymmetric 微波段时域有限差分法瞬态分析收发模块光电子技术硅衬底

在线全文

学校读者我要写书评

暂无评论

不对称轴手性化学（英文）

不对称轴手性化学（英文）

Value of plasma ADMA in predicting cardiac structure and function of patients with chronic kidney diseases

中国化学会·第十六届全国有机合成化学学术研讨会

作者：谭斌南方科技大学

Axially chiral compounds(轴手性化合物)in which the chirality originates from highly sterically hindered rotation along a chiral axis rather than a stereogenic center with four different substituents have received much attention from chemists because of their widespread appearance in biologically active compounds and useful chiral ligands in asymmetric catalysis. Owing to the importance of this structural motif,the catalytic atroposelective construction of axially chiral scaffolds has been intensively investigated and great progress has been accomplished.2 However,the majority of methodologies in this field focused on the use of metal catalysis,whereas synthetic approaches involving organocatulysis have started to emerge only recently. We describe some advances from our group in organocatalytic atroposelective synthesis of axially chiral compounds involving the following strategies:enantioselective cross coupling of two aryl counterparts,asymmetric construction of an aromatic ring and kinetic resolution/desymmetrization and so on.

关键词： Axial Chirality asymmetric Organocatalysis Atroposelective Synthesis

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

China Medical Abstracts(Internal Medicine) 2012年第4期29卷 228-228页

作者：叶建华 Dept Nephrol General HospNingxia Med Univ

Objective To explore the predicting value of plasma asymmetric dimethylarginine (ADMA) in cardiac structure and function of patients with chronic kidney diseases(CKD). Methods A total of 100 CKD patients were enrolled... 详细信息

关键词： predicting staging sectional asymmetric enrolled guideline ejection cardiovascular stepwise crease

Non-covalent organocatalysis by N-heterocyclic carbenes

在线全文

学校读者我要写书评

暂无评论

Science Foundation in China 2015年第1期23卷 22-22页

*** Yong’s laboratory at Peking University,Shenzhen Graduate School,reported the first highly enantioselective non-covalent catalysis using iV-heterocyclic carbenes(NHC).This work was published in Nature Communications(2014,5:3437).In the past decade,asymmetric catalysis using non-metal,small organic molecules has emerged as a new frontier for assembling chemical bonds in an optically enriched *** unparalleled success using

关键词： covalent heterocyclic catalysis assembling asymmetric bonds frontier enriched Peking chiral

Aerosol transportation in horizontal channels w让h gravitational effects

在线全文

学校读者我要写书评

暂无评论

Particuology 2019年第3期17卷 159-168页

作者： Yongwei Gao Ke Zhong Yanming Kang School of Environmental Science and Engineering Donghua University Shanghai 201620 China School of Physics and Electronic-Electrical Engineering Ningxia University Yinchuan 750021 China

Aerosol particle deposition in a narrow horizontal channel with gravitational effects is studied in the laminar flow regime. A general explic让 solution for predicting the aerosol transportation in the channel is obtained theoretically. The characteristics of the asymmetric concentratio n profiles and their dependence on gravitational settling are analyzed for different settings of the diffusion and sedimentation parameters. Aerosol deposition on the channel walls, which is influenced by a combination of mechanisms, is also analyzed. The results are compared with those from simplified models obtained in previous studies in which only diffusion or gravity was considered. The analysis reveals that the literature results regarding this aspect may be simplified with the present solution under specific conditions.

关键词： Exact solution Combined deposition Gravitational effect Horizontal channel asymmetric distribution

Enantioselective Alkynylation of Benzaldehyde Catalyzed by New Chiral Lewis Acid Ligand: Zinc-Amide Complex

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

合成化学 2004年第Z1期12卷 53-53页

作者： Kang Yong-feng , Wang Rui 1 ?1,2 , Liu Lei1, Yan Wen-jin , Xu Zhao-qing , Zhou Yifeng , Chen Chao1, 1 1 1 Tang Ning Xu Jiangke 1 1. Department of Biochemistry & Molecular Biology, School of Life Sciences, Lanzhou University, Lanzhou, Gansu 730000, China 2. State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou Gansu 730000 China Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou Gansu 730000 China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences L

The enantioselective alkynylzinc addition to aldehydes is very useful for the synthesis of chiral propargyl alcohols which are important versatile building blocks of many biologically active compounds and natural products1. A series of chiral oxazolidines were conveniently synthesized from amino acids in three steps with good yields. The use of chiral Lewis acid ligand: zinc-amide complex in situ generated from this oxazolidine with alkylzinc as chiral catalysts for the enantioselective alkynylation of benzaldehyde provides a simple, practical and inexpensive method to generate chiral propargyl alcohols with 93% ee. We report the first example of this asymmetric reaction catalyzed by a chiral Lewis acid ligand: zinc-amide complex ligand(scheme 1). A further investigation of the zinc-amide complex ligand is currently underway.

关键词： asymmetric addition, phenylacetylene, oxazolidine, benzaldehyde