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   17篇
  免费   0篇
化学   17篇
  2021年   1篇
  2018年   3篇
  2017年   1篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2013年   1篇
  2012年   2篇
  2011年   1篇
  2009年   1篇
  2008年   3篇
  2003年   1篇
排序方式: 共有17条查询结果,搜索用时 281 毫秒
1.
Direct synthesis of hydrogen peroxide from hydrogen and oxygen is being actively studied as an alternative to the current manufacturing process. The direct synthesis route has not reached the point of commercialization because of low yields, but significant effort is being spent on enhancing the productivity. With advances in computational capacity, simulation studies based on DFT calculations now offer directions for catalyst improvement, but such modifications can only be realized through the application of nanoparticle synthesis techniques that allow for nanocrystal morphology and size control and unique immobilization. To date, there have only been a small number of studies on such nanoparticles with size and crystallographic homogeneity for the direct hydrogen peroxide synthesis. According to our knowledge no other group has systematically investigated application of nanoparticles in direct synthesis of hydrogen peroxide, and thus included in this review are primarily previous studies conducted by our group. In this review, we discuss the utilization of nanotechnology for the synthesis of Pd catalysts and its effect on the direct synthesis of hydrogen peroxide, and we suggest a direction for future studies.  相似文献   
2.
In a previous work [1] we showed that the swelling behavior of carboxylated core-shell particles (PS-PC) can be modified using a specific sample preparation route or favoring the hydrophobic attractive interaction by other way, i.e. controlling the temperature. In that paper, we found that the swelling was promoted in those particles which were initially in a highly swollen state (pH?10) while it was hindered for those particles which were not previously in this trigger pH. In this work, we present a discussion of the salt-induced swelling of the same carboxylated core-shell system (PS-PC) with two tuned swelling behaviors: the former, called A-2, exhibits promoted swelling while in the latter, called B-1, the swelling is greatly suppressed because of a compact conformation of the polymer shell is induced [1]. Good agreement between experimental, numerical and theoretical results at all pH values is obtained for promoted particles (A-2). On the other hand, the salt-induced swelling behaviors shown by hindered particles (B-1) corroborate that polymer restructuring includes assembly among ionic groups which affect their ionization degree and also the electrosteric interaction between particles. Finally, the salt-induced swelling behavior shown by the B-1 system at pH 8.6 resembles the Pincus regime predicted by scaling theory.  相似文献   
3.
The direct hydroxylation of benzene using molecular oxygen by atmospheric pulse DC corona discharge was investigated. The conversion of benzene increased with the increase of oxygen content and input voltage but the selectivity of phenol decreased due to the formation of polymerized products. The reactivity was also influenced by the kind and content of background inert gas. By using argon as background gas, we could get 2.2% of phenol yield at 60°C and 1 atm with energy consumption of 50 W. The strategy of reductive oxidation, which added hydrogen to the reactant, was not favorable to the phenol formation in this reaction system. The polymerized product showed the oligomeric character and the analysis of its chemical structure with FT–IR was presented.  相似文献   
4.
By conducting a structure-activity relationship study of the backbone of a series of oligoamide-foldamer-based α-helix mimetics of the Bak BH3 helix, we have identified especially potent inhibitors of Bcl-x(L). The most potent compound has a K(i) value of 94 nM in vitro, and single-digit micromolar IC(50) values against the proliferation of several Bcl-x(L)-overexpressing cancer cell lines.  相似文献   
5.
6.
The catalytic reduction of NOx with CO over Pd/Al2O3 and Pd/TiO2/Al2O3 under simulated post Euro-IV diesel exhaust conditions was studied. The catalytic activities obtained by using various Pd and TiO2 loadings and total amounts of reductant and the influence of H2 and H2O was investigated.  相似文献   
7.
8.
9.
A poly(methacrylamide-co-methylmethacrylate) (abbreviated PMAA-MMA) polymer support was studied for supporting a heteropolyacid (tungstophosphoric acid, H3PW12O40) with its surface positively charged in the polymerization step. PMAA-MMA supports could be obtained in a porous form by eliminating template reagent molecules (benzylmalonic acid) combined with properly selected monomer (methacrylamide). The amount of amine groups in PMAA-MMA directly determined the amount of H3PW12O40 impregnated, because the amine groups induced a positive charge on the PMAA-MMA surface. Finally, H3PW12O40/PMAA-MMA showed better acid catalytic activities than unsupported H3PW12O40 in alkylation of 1,3,5-trimethylbenzene with cyclohexene, which confirmed that PMAA-MMA supported H3PW12O40 effectively.  相似文献   
10.
The effects of Ru on the self-reducibility of Ru-doped Ni/MgAl2O4 catalysts, which do not need pre-reduction treatment with H2, were investigated in the steam reforming of methane (SRM). The Ru-promoted Ni/MgAl2O4 catalysts with various amounts of Ru (0–0.5 wt%) were prepared by stepwise impregnation and co-impregnation methods using hydrotalcite-like MgAl2O4 support. For comparison, Ru/MgAl2O4 catalysts with the same amount of Ru were also prepared by the impregnation method. The catalysts were characterized by the N2-sorption, XRD, H2-TPR, H2-chemisorption, and XPS methods. Ni/MgAl2O4 catalyst in the presence of even the trace amount of Ru (Ru content ≥0.05 wt%) showed higher conversion without pre-reduction as compared to Ru/MgAl2O4 catalysts in SRM under the same conditions. The self-activation of Ru–Ni/MgAl2O4 catalysts is mainly attributed to the spillover of hydrogen, which is produced on Ru at first and then reduces NiO species under reaction conditions. Besides, Ru doping makes the reduction of NiO easier. The stepwise impregnated Ru/Ni/MgAl2O4 catalyst produced superior performance as compared to co-impregnated Ru–Ni/MgAl2O4 catalyst for SRM.  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