首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   39篇
  免费   14篇
  国内免费   11篇
化学   34篇
力学   6篇
数学   1篇
物理学   23篇
  2023年   1篇
  2022年   2篇
  2021年   1篇
  2020年   7篇
  2019年   1篇
  2018年   3篇
  2017年   1篇
  2016年   4篇
  2015年   2篇
  2014年   3篇
  2013年   7篇
  2012年   7篇
  2011年   11篇
  2010年   4篇
  2009年   4篇
  2008年   5篇
  2007年   1篇
排序方式: 共有64条查询结果,搜索用时 15 毫秒
31.
For the conventional translational shape-invariant potentials (TSIPs), it has demonstrated that the phase contribution devoted by the scattered subwaves in the analytical transfer matrix quantization condition is integrable and independent of n. Based on this fact we propose a novel strategy to generate the whole set of conventional TSIPs and classify them into three types. The generating functions are given explicitly and the Morse potential is taken as an example to illustrate this strategy.  相似文献   
32.
合成了两个中位苯基上具有甲氧基取代基的铜咔咯配合物(Tp-OCH3PC)Cu和(To,p-(OCH3)2PC)Cu,通过紫外-可见、红外光谱、元素分析、核磁共振及质谱对它们进行了表征。研究了配合物在非水溶剂中的电子顺磁共振、电化学和光谱电化学性质,结果表明无论在固体状态还是在非水溶剂中,配合物的中心金属离子均为三价铜Cu(Ⅲ),在给定的溶剂中Cu(Ⅲ)可以发生可逆的还原反应生成Cu(Ⅱ),也可以被可逆氧化为Cu(Ⅲ)的阳离子自由基。探讨了甲氧基取代基以及溶剂对配合物的紫外-可见光谱和氧化还原电位的影响。  相似文献   
33.
Two new d10 metal–organic frameworks based on a novel semi-rigid aromatic biscarboxylate ligand, namely, [Zn ( RGAA )( BPY )1/2] ( 1 ) and [Cd5(μ3-OH)2( RGAA )4] ( 2 ) [H2 RGAA = 4-(carboxymethyl)-2-ethoxybenzoic acid, BPY = 4,4′-bipyridine], have been synthesized by the hydrothermal reaction, and characterized by Fourier transform-infrared, elemental analyses, X-ray single-crystal diffraction, powder X-ray diffraction and thermogravimetric analyses. Complex 1 displays a three-dimensional (3D) network with a (2,3,4)-connected (6ˆ3.8ˆ2.10)2(6ˆ3)2(8) topology, while complex 2 exhibits a 3D framework with a (3,10)-connected (3.4.5)2(3ˆ4.4ˆ6.5ˆ18.6ˆ14.7ˆ2.8) topology. The luminescent properties of compounds 1 and 2 have been investigated in detail, where the emission maxima are 464 and 349 nm, respectively.  相似文献   
34.
We study the colour-locked twin-noisy-field correlation effects in the fifth-order nonlinear susceptibility of ultrafast polarization beats in a cascade four-level system. More importantly, the fifth-order phase-sensitive heterodyne detection of ultrafast polarization beats has been exploited. The fifth-order nonlinear optical response can be controlled and modified through the colour-locked correlation of twin noisy fields. Thus, this method with the phase dispersion information is a good way to measure the real and imaginary parts of the fifth-order nonlinear susceptibility.  相似文献   
35.
Palladium-catalyzed asymmetric allylic alkylation of acyclic ketones represents a significant challenge in organic synthesis. We report herein that the synthesis of chiral 2,2-disubsituted pyrrolidines from acyclic ketones has been accomplished by using catalytic asymmetric method in the presence of Pd(dba)2 and (R)-binap ligand. Theses reactions occur between allyl methyl carbonate and unstabilized acyclic lithium enolates to provide the products in moderate to good enantioselectivity (up to 81% ee).  相似文献   
36.
Su  Jing-Jing  Zhang  Sheng  Ding  Cui-Cui 《Nonlinear dynamics》2021,106(3):2415-2429
Nonlinear Dynamics - Under investigation in this paper is the generalized AB system, which is extended from the well-known AB system that is used to describe the evolution of the wave packets in a...  相似文献   
37.
Under investigation in this paper is a generalized (3+1)-dimensional Kadomtsev–Petviashvili equation in fluid dynamics and plasma physics. Soliton and one-periodic-wave solutions are obtained via the Hirota bilinear method and Hirota–Riemann method. Magnitude and velocity of the one soliton are derived. Graphs are presented to discuss the solitons and one-periodic waves: the coefficients in the equation can determine the velocity components of the one soliton, but cannot alter the soliton magnitude; the interaction between the two solitons is elastic; the coefficients in the equation can influence the periods and velocities of the periodic waves. Relation between the one-soliton solution and one-periodic wave solution is investigated.  相似文献   
38.
建立红外光谱法测定复方枸橼酸阿尔维林软胶囊中西甲硅油的含量.选用正己烷萃取西甲硅油,根据聚二甲基硅氧烷在1260cm-1波数处Si-CH3基团的对称变形振动有特征吸收峰,使用红外光谱波数为1330-1180cm-1,分辨率:2.0cm-1,狭缝:宽,响应:快;温度:25℃;相对湿度:50%.在选定的分析条件下,系统适用性、精密度和稳定性良好;西甲硅油在1.0-24.0mg·mL-1浓度范围内呈良好线性关系(r=0.9965);加标回收率为100.79% (RSD=1.68%,n=9); 3批样品含量测定结果分别为标示量的98.70%、97.93%、98.58%.该法简便、快速、专属性强、精密度高,适用于复方枸橼酸阿尔维林软胶囊中西甲硅油的含量测定.  相似文献   
39.
以2,4-二硝基苯肼作为衍生化试剂,采用高效液相色谱法定量检测了大气细粒子(PM2.5)中二羰基类化合物。以乙二醛和甲基乙二醛为目标化合物,对二羰基类化合物采样条件(采集时间,流速等)、样品处理及分析条件进行了优化。研究表明,利用3mL衍生化溶液(含0.25mmol/LHCl和30μL饱和DNPH-乙腈溶液)和3mL乙腈可有效提取滤膜上的二羰基类化合物;本方法在滤膜采样12h内的采样及洗脱效果较好。利用此方法对上海市宝山区上海大学和崇明东平国家森林公园大气细粒子(PM2.5)中二羰基化合物进行了检测。  相似文献   
40.
Deng  Gao-Fu  Gao  Yi-Tian  Su  Jing-Jing  Ding  Cui-Cui  Jia  Ting-Ting 《Nonlinear dynamics》2020,99(2):1039-1052
Nonlinear Dynamics - Fluid mechanics has the applications in a wide range of disciplines, such as oceanography, astrophysics, meteorology, and biomedical engineering. Under investigation in this...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号