检索结果-南通市图书馆

Cerium Salt Promoted Homocoupling Reaction of Dialkylanilines in Water

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2008年第2期24卷 226-230页

作者： YANG xiang-hua LU Wen-chao LIAO qian xi Chan-juan Key Laboratory for Bioorganic Phosphorus Chemistry ＆ Chemical Biology Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 P. R. China

Highly regioselective homocoupling of N,N-dialkylanilines can be achieved in water with cerium reagents, in which various N,N,N′,N′-tetraalkylbenzidines are obtained from N,N-dialkylanilines either by direct oxidati... 详细信息

关键词： Homocoupling Regioselectivity Cerium salts N,N-Dialkylaniline N,N,N′,N′-Tetraalkylbenzidine

Enhancing the ionic conductivity in a composite polymer electrolyte with ceramic nanoparticles anchored to charged polymer brushes

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第3期31卷 831-835页

作者： Bintao Zhao xi Lu qian Wang Jingfa Yang Jiang Zhao Henghui Zhou College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China Pulead Technology Industry Co.Ltd. Beijing 102200China Institute of Chemistry Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Polymer electrolytes a re essential for next-gene ration lithium batteries because of their excellent safety ***,low ionic conductivity is the main obstacle restricting their commercial *** with nanoparticles are a promising route to overcome this *** this work,lithium polystyrene sulfonate brushes(LiPSS)is anchored to silicon dioxide nanoparticles with chemical bonding using atom transfer radial polymerization(SI-ATRP).The composite polymer electrolytes are made by mixing vinylene carbonate and nanoparticles via a facile in situ polymerization *** ionic conductivity of composite polymer electrolytes is improved to 7.2×10^-4 S/cm at room temperature,which is attributed to the low degree of crystallinity of polymer electrolyte and the fast ion transport on the surfaces of polymer brush layers that act as a conductive *** composite polymer electrolytes show a wide electrochemical window of approximately 4.5 V ***^+/Li and excellent cycling performance retention of approximately 95%after 100 cycles at ambient *** results also prove that surface groups of ceramic na noparticles are an important way to increase the electrochemical properties of composite polymer electrolytes.

关键词： Polymer electrolyte Polymer brushes Solid batteries Nanoparticles Composite electrolyte

THERMO-RESPONSIVE BLOCK COPOLYMERS BASED ON LINEAR-TYPE POLY(ETHYLENE GLYCOL):TUNABLE LCST WITHIN THE PHYSIOLOGICAL RANGE

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2012年第5期30卷 770-776页

作者： Guo-liang Yue qian-ling Cui Yu-xi Zhang Er-jian Wang 吴飞鹏 Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing100190China Graduate School of Chinese Academy of Sciences Beijing100049China

Therrno-responsive block copolymers poly（ethylene glycol）-block-poly（N-acryloyl-2,2-dimethyl-1,3-oxazolidine）, PEG-b-PADMO, based on linear PEG were prepared via a versatile reversible addition-fragmentation chain transfer （RAFT） polymerization, PEG22 （Mw = 1000） was used as the hydrophilic component, whose dehydration was the main driving force for the phase transition of these copolymers, as demonstrated by the tH-NMR spectra. Their lower critical solution temperatures （LCSTs） could be tuned in the range of 20℃ to 35℃, by adjusting the degree of polymerization （DP） of PADMO between 14-27. Furthermore, a sharp phase transition at ca. 33℃, close to the physiological temperature with minimal hysteresis, was observed for the PEGzz-b-PADMO14 copolymer. Moreover, excellent reversibility and reproducibility were displayed for the same copolymer over 10 cycles of repeated temperature change between 25℃ （below the LCST） and 40℃ （above the LCST）.

关键词： Thermo-responsive Block copolymers Linear PEG Phase transitions.

乡村振兴背景下成都乡村饮食文化资源开发研究:基于旅游体验价值

在线全文

学校读者我要写书评

暂无评论

江苏商论 2025年第1期 3-6,10页

作者：赵豫西冉杰李倩周媛媛四川旅游学院四川成都610100

党的十九大提出实施乡村振兴战略,发展旅游业是乡村振兴的重要途径,而饮食文化资源是乡村旅游发展的核心资源之一,为促进乡村旅游的高质量发展提供了强大的动力。基于此,本文通过分析成都乡村饮食文化资源开发的现状,在此基础上提出乡... 详细信息

党的十九大提出实施乡村振兴战略,发展旅游业是乡村振兴的重要途径,而饮食文化资源是乡村旅游发展的核心资源之一,为促进乡村旅游的高质量发展提供了强大的动力。基于此,本文通过分析成都乡村饮食文化资源开发的现状,在此基础上提出乡村振兴背景下乡村饮食文化资源开发对策。

关键词：乡村振兴饮食文化资源体验价值

Coarsening behavior of MX carbonitrides in type 347H heat-resistant austenitic steel during thermal aging

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2016年第3期23卷 283-293页

作者： Ying-hui Zhou Chen-xi Liu Yong-chang Liu qian-ying Guo Hui-jun Li State Key Lab of Hydraulic Engineering Simulation and Safety School of Materials Science and Engineering Tianjin University

In this work, the growth kinetics of MX （M - metal, X - C/N） nanoprecipitates in type 347H austenitic steel was systematically studied. To investigate the coarsening behavior and the growth mechanism of MX carbonitrides during long-term aging, experiments were performed at 700, 800, 850, and 900℃ for different periods （1, 24, 70, and 100 h）. The precipitation behavior of carbonitrides in specimens subjected to various aging conditions was explored using carbon replicas and transmission electron microscopy （TEM） observations. The corresponding sizes ofMX carbonitrides were measured. The results demonstrates that MX carbonitrides precipitate in type 347H austenitic steel as Nb（C,N）. The coarsening rate constant is time-independent; however, an increase in aging temperature results in an increase in coarsening rate of Nb（C,N）. The coarsening process was analyzed according to the calculated diffusion activation energy of Nb（C,N）. When the aging temperature was 800-900℃, the mean activation energy was 294 kJ·mol -1, and the coarsening behavior was controlled primarily by the diffusion of Nb atoms.

关键词： austenitic steel heat resistance carbonitrides coarsening nanoparticles diffusion thermal aging

A wireless solution for greenhouse monitoring and control system based on ZigBee technology

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第10期8卷 1584-1587页

作者： ZHANG qian YANG xiang-long ZHOU Yi-ming WANG Li-ren GUO xi-shan School of Biosystem Engineering and Food Science. Zhejiang University. Hangzhou 310029 China

With the rapid development of wireless technologies, it is possible for Chinese greenhouses to be equipped with wireless sensor networks due to their low-cost, simplicity and mobility. In the current study, we compared the advantages of ZigBee with other two similar wireless networking protocols, Wi-Fi and Bluetooth, and proposed a wireless solution for green- house monitoring and control system based on ZigBee technology. As an explorative application of ZigBee technology in Chinese greenhouse, it may promote Chinese protected agriculture.

关键词： Greenhouse Monitoring and control Wireless ZigBee IEEE802.15.4 JN5121

A nonlocal Burgers equation in atmospheric dynamical system and its exact solutions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第1期28卷 189-194页

作者： xi-Zhong Liu Jun Yu Zhi-Mei Lou xian-Min qian Institute of Nonlinear Science Shaoxing UniversityShaoxing 312000China Yuanpei College Shaoxing UniversityShaoxing 312000China

From a two-vortex interaction model in atmospheric and oceanic systems, a nonlocal counterpart with shifted parity and delayed time reversal is derived by a simple AB reduction. To obtain some approximate analytic solutions of this nonlocal system, the multi-scale expansion method is applied to get an AB-Burgers system. Various exact solutions of the AB-Burgers equation, including elliptic periodic waves, kink waves and solitary waves, are obtained and shown *** show the applications of these solutions in describing correlated events, a simple approximate solution for the two-vortex interaction model is given to show two correlated dipole blocking events at two different places. Furthermore, symmetry reduction solutions of the nonlocal AB-Burgers equation are also given by using the standard Lie symmetry method.

关键词： AB–BA equivalence principle nonlocal Burgers equation periodic waves

Relationship between settlements and topographical factors:An example from Sichuan Province,China

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2018年第9期15卷 2043-2054页

作者： xi Chang-bai qian Tian-lu CHI Yao CHEN Jie WANG Jie-chen Department of Geographic Information Science Nanjing UniversityNanjing 210023China Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Nanjing UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Terrain can influence the spatial distribution of settlements. Studies on the terrain characteristics of settlements can help to understand the effects of the environment on human activities. This paper provides a quantitative analysis of the relationship between settlements and topographical factors. A statistically significant sample of residential locations and ASTER GDEM V2 were used to investigate terrain traits and settlements distributions. We selected eight topographical factors and introduced a practical concept, distributive entropy, into assessing the aggregation extent of the settlements' spatial distribution. The study showed that topography varies within the study area, and distributive entropy indicates that settlements have distinctive distribution tendency in statistic approach. According to the results of this study, mountain inhabitants prefer to settle in valleys. Additionally, with distributive entropy, residential suitability was divided to three levels: suitable, normal, and unsuited. The results showed that suitable area is small in Sichuan Province, accounting for 8.2%～29.9%; however, unsuited area is large, accounting for 33%～63.3%.

关键词： Settlement Topographical factor Distributive entropy Spatial pattern GeographicalInformation System

An Intrinsic Model for the Polarization Position Angle Swing Observed in QSO 1150+812

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2004年第1期4卷 37-50页

作者： Shan-Jieqian xi-ZhenZhang NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012

The rapid polarization position angle swing of ~ 180° observed in QSO 1150+812 at 2cm by Kochenov and Gabuzda is quite a regular event. One interesting property of the event is that, during the time of the swing the polarized flux density remained almost constant. We suggest that such an event can be explained in terms of a relativistic thin shock propagating through a uniform helical magnetic field, giving rise to relativistic aberration effects as the transverse field component rotates. The model may also be applicable to other similar events in which variations in polarization are not accompanied by variations in total flux density.

关键词： radio continuum: galaxies polarization quasars: individual: QSO 1150+812