检索结果-南通市图书馆

Chinese Journal of Chemistry 2022年第19期40卷 2345-2355页

作者： Lei Wu minyan wang Yong Liang Zhuangzhi Shi State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjingJiangsu210093 China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHenan453007 China

Monofluoroalkenes are important and versatile privileged components in pharmacologically relevant ***,we report a method for the selective construction of these compounds in a diversity-oriented fashion through regiodivergent cross-coupling of gem-difluorocyclopropanes with allylboronates by employing a palladium catalyst with two different ligands,in which gem-difluorocyclopropanes were used as allyl electrophiles by C—C and C—F bond *** the presence of 2-biphenylyl(diphenyl)phosphine as ligand,the linear-selective allyl–allyl bond formation is highly obtained,while utilizing the sterically hindered BrettPhos(dicyclohexyl[3,6-dimethoxy-2',4',6'-tris(1-methylethyl)[1,1'-biphenyl]-2-yl]phosphine)as the ligand favors the generation of the branched-selective *** and computational studies investigated the key steps of the cross-coupling reactions,revealing the origin of the ligand-controlled regiodivergence.

关键词： Allylation C-C activation Cross-coupling gem-Difluorocyclopropanes Defluorination

Physico-chemical characterization and source tracking of black carbon at a suburban site in Beijing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2015年第7期27卷 188-194页

作者： Hailin wang Lei Nie Dan Liu Meiping Gao minyan wang Zhengping Hao National Urban Environmental Pollution Control Engineering Techniques Research Center Beijing Municipal Research Institute of Environmental Protection Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nan-jing University of Information Science and Technology Department of Chemical Engineering School of Chemical & Environmental Engineering China University of Mining & Technology Department of Environmental Nano-materials Research Center for Eco-Environmental Sciences Chinese Academy of Sciences

Particles from ambient air and combustion sources including vehicle emission, coal combustion and biomass burning were collected and chemically pretreated with the purpose of obtaining isolated BC（black carbon） samples. TEM（transmission electron microscopy）results indicate that BC from combustion sources shows various patterns, and airborne BC appears spherical and about 50 nm in diameter with a homogeneous surface and turbostratic structure. The BET（Barrett-Emmett-Teller） results suggest that the surface areas of these BC particles fall in the range of 3-23 m2/g, with a total pore volume of 0.03-0.05 cm3/g and a mean pore diameter of 7-53 nm. The nitrogen adsorption-desorption isotherms are indicative of the accumulation mode and uniform pore size. O2-TPO（temperature programmed oxidation）profiles suggest that the airborne BC oxidation could be classified as the oxidation of amorphous carbon, which falls in the range of 406-490℃ with peaks at 418, 423 and 475℃,respectively. Generally, the BC characteristics and source analysis suggest that airborne BC most likely comes from diesel vehicle emission at this site.

关键词： Black carbon Characterization Source emission Beijing

Decarboxylative cyanation and thiocyanation via catalytic electron donor-acceptor complex with copper catalysis

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第9期67卷 3019-3028页

作者： Hongping Zhao Xiaoxiang Xi Tianbao Wu Zimin Chen minyan wang Weiming Yuan Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Bioinorganic Chemistry and Materia MedicaSchool of Chemistry and Chemical EngineeringHuazhong University of Science and Technology(HUST)Wuhan 430074China State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210093China Shenzhen Huazhong University of Science and Technology Research Institute Shenzhen 518000China

A new catalytic decarboxylative cyanation and thiocyanation via a synergistic Na I/Cu catalysis is *** photoexcited electron donor-acceptor complex by assembly of Na I,R3P,and N-acyloxy-phthalimide ester(NHPI ester)triggers the generation of alkyl radical species,which then engages in Cu-catalyzed radical coupling *** to success of this dual catalytic transformation is the reliable charge transfer between I·and Cu(I).This dual catalytic platform can eliminate the use of expensive iridium-based photocatalyst or synthetically elaborate organic dyes.A series of primary,secondary,and tertiary alkyl nitriles and thiocyanates are easily ***,an asymmetric decarboxylative cyanation by applying a chiral Cu catalyst is also developed to afford chiral nitriles in high *** mechanistic details and the origin of the high enantioselectivity are further investigated by the mechanistic experiments and the density functional theory calculations.

关键词： electron donor-acceptor catalysis copper catalysis cyanation thiocyanation asymmetric synthesis

Transition-Metal-Free Defluorosilylation of Fluoroalkenes with Silylboronates

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2019年第10期37卷 1009-1014页

作者： Pan Gao Guoqiang wang Longlong Xi minyan wang Shuhua Li Zhuangzhi Shi State Key Laboratory of Coordination Chemistry Chemistry and Biomedicine Innovation Center(ChemBIC)School of Chemistry and Chemical EngineeringNanjing UniversityNanjingJiangsu 210093China Key Laboratory of Mesoscopic Chemistry of Ministry of Education Institute of Theoretical and Computational ChemistrySchool of Chemistry and Chemical EngineeringNanjing UniversityNanjingJiangsu 210093China

Silylated fluoroalkenes are important synthetic intermediates with complementary reactivity,which play a key role in the construction of natural products,pharmaceuticals,and manmade *** the normally highly stable fiuoroalkenes into silylated fluoroalkenes by selective defluorosilylation is a challenging ***,we report a simple,inexpensive and robust defluorosilylation of a variety of fluoroalkenes with silylboronates in the presence of alkoxy base to directly synthesize various silylated *** protocol features mild and safe reaction conditions that avoid a catalyst,a transition metal,a ligand,and high reaction temperature and tolerates a wide scope of fluoroalkene substrates without compromising the *** functional theory calculations show that transient silyl anion complex undergoes an SN2,or SNv substitution,which is responsible for this base-mediated defluorosilylation.

关键词： materials. alkenes nates

Pre-Processing,Quality Assurance,and Use of Global Atmospheric Motion Vector Observations in CRA

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2022年第6期36卷 947-962页

作者： minyan wang Shuang YAO Lipeng JIANG Tao ZHANG Chunxiang SHI Ting ZHU National Meteorological Information Centre China Meteorological AdministrationBeijing 100081 CMA Earth System Modeling and Prediction Centre China Meteorological Administration(CMA)Beijing 100081

Assimilation of atmospheric motion vectors(AMVs)is important in the initialization of the atmospheric state in numerical weather prediction models,especially over oceans and at high latitudes where conventional data are *** paper presents a detailed description of the pre-processing,quality assurance,and use of global AMVs in China’s first generation of the 40-yr(1979-2018)CRA global atmospheric reanalysis product.A new AMV archive is integrated from near real-time operational Global Telecommunication System data and reprocessed AMV datasets released or produced mainly during 2014-2016 according to a priority *** avoid the misuse of data with systematic quality problems,the observations of all 18 types of AMVs from 54 satellites are pre-evaluated over the whole time *** pre-evaluation system developed by the CRA team is based on the NCEP Gridpoint Statistical Interpolation(GSI)three-dimensional variational assimilation system and the ERA-Interim reanalysis *** AMVs in the new AMV archive are denser than the AMVs prepared for the Climate Forecast System Reanalysis product,the bias and root-mean-square values are smaller,and the time series are *** new AMV archive is assimilated in the CRA product based on the NCEP GSI assimilation procedure and quality control configuration with reference to the pre-evaluation *** is the first time that the reprocessed AMVs from Fengyun-2 satellites from June 2005 to July 2017 are assimilated in a reanalysis *** assimilation features inspire confidence in the accuracy and stability of these *** mean root-mean-square values of the observation minus analysis infrared,water vapor,and visible AMV were 1.5-3.4,2.7-3.6,and 1.3-2.1 m s-1,*** experience of integrating,pre-evaluating,and assimilating AMV observations is valuable for the next generation of reanalysis products.

关键词： reanalysis CRA(China’s first generation of 40-yr global atmospheric ReAnalysis product) atmospheric motion vector integration assimilation reprocessed data

Stereoselective fluoroarylation of 1,1-difluoroallenes enabled by palladium catalysis

在线全文

学校读者我要写书评

暂无评论

Green Synthesis and Catalysis 2020年第2期1卷 134-142页

作者： Huanhuan Luo Yunfei Zhao Dawei wang minyan wang Zhuangzhi Shi State Key Laboratory of Coordination Chemistry Chemistry and Biomedicine Innovation Center(ChemBIC)School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210093China School of Chemical and Material Engineering Jiangnan UniversityWuxi 214122China

A novel protocol for palladium-catalyzed fluoroarylation of 1,1-difluoroallenes was described *** reaction proceeded smoothly under mild condition and various trifluoromethylated alkenes were obtained in moderate yields with excellent E *** mechanism involving a vital trifluoromethylated vinyl silver intermediate,which generated through the F-nucleophilic addition to 1,1-difluoroallenes,has been proposed.

关键词： Allenes Fluoroarylation Stereoselectivity Trifluoromethylated alkenes Palladium catalysis

Synergistic Suppression of Cortical Spreading Depression under NR2A and NR2B Inhibition

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pharmacology & Pharmacy 2015年第12期6卷 573-579页

作者： Yiman Jia Jiayi Zhou Fan Bu minyan wang Centre for Neuroscience Department of Biological Sciences Xi’an Jiaotong-Liverpool University Suzhou China

Cortical spreading depression (CSD) is a transient synaptic excitation, followed by depression, which can propagate slowly across cortex, subcortex and retina. CSD is implicated in migraine with aura and may lead to migraine pain. CSD can be suppressed by inhibition of both NR2A and NR2B containing N-methyl-D-aspartic acid (NMDA) receptors. However, whether there is a synergistic effect of co-inhibition of NR2A and NR2B containing receptors on CSD remains unknown. In this study, an efficient in vitro model of migraine with intrinsic optical imaging approach was applied to address this role of co-activation of both NR2A and NR2B in CSD. The results showed that co-application of NVP-AAM077, a drug selectively targeting for NR2A and Ro 25-6981, a drug selectively targeting for NR2B containing receptors, showed synergistic inhibitory effects on propagation rate and the magnitude of CSD in a concentration dependent manner in chick retina. Inhibition of CSD propagation was also observed by a clinical acceptable drug that antagonizes both NR2A and NR2B containing receptors, memantine, at 10 μM. These data suggest that combinational use of antagonists selectively targeting NR2A and NR2B containing receptors could be a useful strategy for preventative treatment of migraine with improved efficacy with potential alleviated side effects.

关键词： Cortical Spreading Depression NR2A NR2B NVP-AAM077 Ro 25-6981 Memantine Chick Retina

CRA-40/Atmosphere—The First-Generation Chinese Atmospheric Reanalysis(1979–2018):System Description and Performance Evaluation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2023年第1期37卷 1-19页

作者： Zhiquan LIU Lipeng JIANG Chunxiang SHI Tao ZHANG Zijiang ZHOU Jie LIAO Shuang YAO Jingwei LIU minyan wang Huiying wang Xiao LIANG Zhisen ZHANG Yan YAO Ting ZHU Zhe CHEN Wenhui XU Lijuan CAO Hui JIANG Kaixi HU National Meteorological Information Centre China Meteorological Administration(CMA)Beijing 100081China National Center for Atmospheric Research BoulderCO 80301USA CMA Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing 100081China

Atmospheric reanalysis reproduces the past atmospheric conditions through assimilation of historical meteorological observations with fixed version of a numerical weather prediction(NWP)model and data assimilation(DA)*** is widely used in weather,climate,and even business-related research and *** paper reports the development of CMA’s first-generation global atmospheric reanalysis(RA)covering 1979–2018(CRA-40;CRA refers to CMA-RA).CRA-40 is produced by using the Global Spectral Model(GSM)/Gridpoint Statistical Interpolation(GSI)at a 6-h time interval and a TL574 spectral(34-km)resolution with the model top at 0.27 hPa.A large number of reprocessed satellite data and widely collected conventional observations were assimilated during the reanalyzing process,including the reprocessed atmospheric motion vector(AMV)products from FY-2C/D/E/G satellites,dense conventional observations(at about 120 radiosonde and 2400 synoptic stations)over China,as well as MWHS-2 and GNSS-RO observations from *** reanalysis fitting to observations is improved over time,especially for surface pressure with root-mean-square error reduced from 1.05 hPa in 1979 to 0.8 hPa,and for upper air temperature from 1.65 K in 1979 to 1.35 K,in *** patterns of global analysis increments for temperature,specific humidity,and zonal wind are consistent with the changes in the observing *** surface temperature from the model’s 6-h forecast reflects the global warming trend *** CRA-40 precipitation pattern matches well with those of GPCP and other ***-40 also successfully captures the QBO and its vertical and temporal development,hemispherical atmospheric circulation change,and moisture transport by the East Asian summer *** is now operationally running in near real time as a climate data assimilation system in CMA.

关键词： CMA reanalysis(CRA) observations data assimilation(DA) forecast model

网络时代我国弱势群体阶层流动困境:表征、根源及对策

在线全文

学校读者我要写书评

暂无评论

中共天津市委党校学报 2020年第3期22卷 58-67页

作者：汪旻艳南京师范大学公共管理学院江苏南京210023

网络时代弱势群体获得了一定的阶层流动机会,但并未完全摆脱阶层流动困境,由此产生的社会对立情绪、社会矛盾和风险日益突出。较之传统时代,网络时代弱势群体阶层流动的困境主要表现在机会困境、动力困境和技术保障困境三个方面,其根源... 详细信息

网络时代弱势群体获得了一定的阶层流动机会,但并未完全摆脱阶层流动困境,由此产生的社会对立情绪、社会矛盾和风险日益突出。较之传统时代,网络时代弱势群体阶层流动的困境主要表现在机会困境、动力困境和技术保障困境三个方面,其根源在于“自我排斥”与“外部排斥”交织循环作用,其结果表现为弱势群体处于相对于网络主流社会、权力中心的边缘境遇,难以与其他社会成员进行互动,产生空间排斥,丧失认同感。通过双向赋权激发弱势群体阶层流动意愿、建立电子包容提供弱势群体阶层流动技术动力、提供网络媒介援助增加弱势群体阶层流动机会是加快弱势群体阶层流动的现实路径。

关键词：网络时代弱势群体阶层流动

在线全文

学校读者我要写书评

暂无评论

利用卫星产品评估数值预报模式云层垂直结构

气象科技 2010年第4期38卷 403-408,I0005页

作者：王旻燕国家气象信息中心北京100081 美国马里兰大学地球系统科学多学科交叉中心(ESSIC) md207403823

对云层垂直结构的准确参数化描述是数值天气预报模式准确计算长短波辐射通量、辐射加热率廓线、云反射率、云辐射效应等参数的重要基础,但地基观测数据无法对模式预报的云层垂直分层情况进行验证。文章基于卫星资料Collection5版本的MO... 详细信息

对云层垂直结构的准确参数化描述是数值天气预报模式准确计算长短波辐射通量、辐射加热率廓线、云反射率、云辐射效应等参数的重要基础,但地基观测数据无法对模式预报的云层垂直分层情况进行验证。文章基于卫星资料Collection5版本的MODIS云产品MOD06,利用国际上能够较准确判别云层垂直分层的一个新算法,以反演的高、中、低云发生频率和云顶气压结果,评估美国国家环境预报中心(NCEP)北美中尺度模式NAM的云层垂直结构。2006年7～10月北美地区(153°～48°W,12°～62°N)的评估结果表明:①卫星反演和模式预报的高、中、低云的云量区域分布比较相似,尤其是高云。热带太平洋地区模式预报高云量大于卫星反演值。模式预报的低云在墨西哥及北美大陆、大西洋地区更多。②卫星反演和模式预报中云发生频率的差异最小,模式预报高云和低云发生频率峰值比卫星反演的峰值更大,且云顶出现的高度更高。③模式预报中云量和低云量的纬度平均值比卫星反演的高,尤其是低云量。NAM的云参数化有待于进一步改进。

关键词：云层垂直结构 MODIS云产品 NCEP数值天气预报模式评估