全文获取类型
收费全文 | 43篇 |
免费 | 3篇 |
国内免费 | 4篇 |
专业分类
化学 | 25篇 |
力学 | 18篇 |
物理学 | 7篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有50条查询结果,搜索用时 296 毫秒
1.
We measured the time decay of the magnetic moment of high Tc superconductors YBa2Cu3O7-δ ceramic samples and found the memory effect which has hitherto been reported only in single crystals. The temperature and field ranges, especially the memory phenomenon in ceramic samples at liquid nitrogen temperature can only be understood in a combined picture of both flux creep and glass behaviour 相似文献
2.
Jin Yuan Ling Wang Yitong Wang Prof. Dr. Jingcheng Hao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(16):3545-3554
Copper nanoclusters (CuNCs) as a new class of fluorescent materials have attracted a great deal of interest due to their outstanding fluorescence properties. In this work, a variety of organic solvents were used to induce self-assembly of glutathione-capped CuNCs (GSH-CuNCs) to form ordered assemblies with enhanced fluorescence properties. Assemblies with multicolor fluorescence emission were constructed on the basis of the aggregation-induced emission (AIE) of GSH-CuNCs and the solvent effect. The fluorescence emission from these GSH-CuNCs assemblies can also be tuned from yellow to purple by changing the organic solvent. A possible mechanism based on the size of the assemblies and electron transfer was explored to explain the solvent effects on GSH-CuNCs. Stimuli-responsive nanoswitches with excellent reversibility can be controlled by changing the type of organic solvent and the ratio of the organic solvent to the aqueous solution of GSH-CuNCs. As the CuNCs assemblies exhibit strong, stable, and color-tunable fluorescence, they were employed as color-conversion materials for recognizing different organic solvents. 相似文献
3.
Junrui Duan Jie Ji Lili Ye Yitong Zhai Lidong Zhang 《Proceedings of the Combustion Institute》2021,38(1):681-689
The low-temperature oxidation mechanism of n?butyl radicals (n-C4H9) has been investigated by high level quantum chemical calculations coupled with the Rice–Ramsperger–Kassel–Marcus/Master Equation (RRKM/ME) theory. The potential energy surfaces (PES) were explored at the QCISD(T)/CBS//B3LYP/6-311++G(d,p) level. The temperature- and pressure-dependent rate constants were computed and fitted in modified Arrhenius parameters. The major reaction channels were discussed to more deeply understand the competing relationships between chain branching, chain propagation and termination reactions. The results show that the 1,5 H-shift reaction is more competitive than the 1,6 H-shift and 1,4 H-shift for isomerization reactions of n?butyl peroxy radicals, and the concerted HO2 elimination channel to form butene becomes more important at high temperatures. Furthermore, based on our calculations, a revised kinetic model was developed to describe n-butane oxidation. Good consistency between model predictions and experimental data was shown. This study enhances our understanding of the combustion mechanism of n-butane and can be used as a reliable reference for mechanistic understanding of larger alkanes. 相似文献
4.
Luyan Li Yahui Cheng Weihua Wang Shiwei Ren Yitong Yang Xiaoguang Luo Hui Liu 《Solid State Communications》2011,151(21):1583-1587
The ferromagnetic properties of Mn- and Co-doped Cu2O with copper and oxygen vacancies (VCu and VO) are studied by first-principles calculations. The results indicate that Mn-doped Cu2O has an antiferromagnetic state in the near configuration, while it has a ferromagnetic state for the far configuration. On the contrary, Co-doped Cu2O possess a ferromagnetic state regardless of the distance between the two Co atoms. The observed ferromagnetism can be attributed to the 90° ferromagnetic super-exchange mechanism. The presence of VO can enhance the ferromagnetism, whereas VCudepresses it. 相似文献
5.
报道了一种高溶解性导电聚苯胺(PANI)的制备方法,以聚2-丙烯酰胺-2-甲基丙磺酸(PAMPS)作为掺杂酸和乳化剂,利用其特有的长链、亲水性及强酸性基团效应,通过乳液聚合法一步合成出具有较高溶解性的导电聚苯胺。利用核磁共振光谱仪(NMR)、傅里叶红外光谱仪(FT-IR)和扫描电子显微镜(SEM)等技术手段对产物结构和性能进行了表征分析。结果表明,在m(苯胺)∶m(AMPS)∶m(APS)=1∶2∶1.5;AMPS质量分数为20%;APS质量分数为30%;反应时间为5 h;反应温度为5℃的条件下,聚苯胺的产率高达86%,在有机溶剂二甲基甲酰胺(DMF)中的溶解度可达0.3814 g/g,在水中的溶解度可达0.2123 g/g,电导率达5.9 S/cm。 相似文献
6.
Mengmeng Zhu Weishuo Li Panpan Xu Jingjing Shi Shan Shao Xiaosi Zhu Yitong Guo Yaowu He Zhao Hu Hongtao Yu Yanan Zhu Igor F. Perepichka Hong Meng 《中国科学:化学(英文版)》2017,60(1):63-76
Thieno[3,2-b]thiophene (TT) monomers end-capped with 3,4-ethylenedioxythiophene (EDOT) moieties are electropolymerized to form π-conjugated polymers with distinct electrochromic (EC) properties. Steric and electronic factors (electron donor and acceptor substituents) in the side groups of the TT core, as well as the structure of the polymer backbone strongly affect the electrochemical and optical properties of the polymers and their electrochromic characteristics. The studied polymers show low oxidation potentials, tunable from–0.78 to +0.30 V (vs. Fc/Fc+) and the band gaps from 1.46 to 1.92 eV and demonstrate wide variety of color palettes in polymer films in different states, finely tunable by structural variations in the polymer backbone and the side chains. EC materials of different colors in their doped/dedoped states have been developed (violet, deep blue, light blue, green, brown, purple-red, pinkish-red, orange-red, light gray, cyan and colorless transparent). High optical contrast (up to 79%), short response time (0.57–0.80 s), good cycling stability (up to 91% at 2000 cycles) and high coloration efficiency (up to 234.6 cm2 C–1) have been demonstrated and the influence of different factors on the above parameters of EC polymers have been discussed. 相似文献
7.
ZhangYitong HaoYongjiang LiCuiyu 《Acta Mechanica Solida Sinica》2004,17(2):131-139
I. INTRODUCTION Previous research on woven fabric ignored the micro-weaving structures in fabric and modeled thewoven fabric as a ?exible orthotropic plate[1??3]. However, such a model is unable to predict certainbuckling phenomena of fabric commonly ob… 相似文献
8.
Bize Gao Dr. Quanren Zhu Prof. Dr. Yanhui Yi Yue Li Guoxing Wu Yitong Guo Prof. Dr. Zhaochi Feng Prof. Dr. Hongchen Guo 《欧洲无机化学杂志》2023,26(22):e202200661
The epoxidation of propylene with dilute H2O2 aqueous solution over titanium silicalite-1 (TS-1) zeolite catalyst is a green chemical reaction for propylene oxide (PO) production. Carrying out the reaction in gas-phase can get rid of problems caused by using methanol solvent. This paper reports an attempt of using non-zeolite catalyst for the gas-phase epoxidation. Amorphous Ti/SiO2, obtained by grafting amorphous SiO2 with TCl4 in ethanol solvent in a chemical liquid-phase deposition (CLD) process, has been used as the catalyst. Results show that the CLD Ti/SiO2 with appropriate Si/Ti molar ratio is an active catalyst for gas-phase epoxidation, achieving 9.8 % propylene conversion and 66.9 % PO selectivity with 40.3 % H2O2 utilization, which indicates that this amorphous Ti/SiO2 catalyst deserves extensive studies in the future. 相似文献
9.
A simple and rapid sample preparation method using accelerated solvent extraction and solid-phase extraction (SPE) cleanup for determining organophosphorus (OP) pesticides in the roots of Platycodon grandiflorum was developed. The OP pesticides were concentrated by use of an SPE cartridge (ENVI-Carb) and quantitatively analyzed and confirmed by capillary gas chromatography with flame photometric detection. The pesticides were eluted from the cartridges with 20 mL acetonitrile-toluene (3 + 1, v/v). The average recovery from 10 g PF grandiflorum roots, fortified at 3 levels ranging from 0.04 to 1.00 mg/kg, was 91.9% with a relative standard deviation of 4.3%. The limits of detection ranged from 1.16 x 10(-3) mg/kg (dimethoate) to 4.64 x 10(-3) mg/kg (dichlorvos). The proposed method showed acceptable accuracy and precision while minimizing environmental concerns, time, and labor. 相似文献
10.
实验表明,在高温下,某些金属材料呈非线性粘弹性:对不同的应变增量,材料有不同的瞬时弹性模量,所产生的应力沿不同的松弛曲线松弛。该了表述材料这一力学行为的变温非线性粘弹性本构方程,它可用于在高温和变温下工作的构件(如模具)的变形计算。 相似文献