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   96篇
  免费   2篇
化学   48篇
晶体学   1篇
力学   1篇
数学   7篇
物理学   41篇
  2021年   4篇
  2020年   5篇
  2018年   1篇
  2017年   2篇
  2016年   2篇
  2015年   1篇
  2014年   2篇
  2013年   2篇
  2012年   6篇
  2011年   7篇
  2010年   7篇
  2009年   5篇
  2008年   3篇
  2007年   5篇
  2006年   4篇
  2005年   8篇
  2004年   3篇
  2003年   5篇
  2002年   2篇
  2001年   2篇
  2000年   7篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1996年   3篇
  1994年   1篇
  1993年   2篇
  1991年   1篇
  1984年   1篇
  1981年   1篇
  1966年   1篇
排序方式: 共有98条查询结果,搜索用时 406 毫秒
1.
Partial critical dependences of the form current-magnetic field in a two-layered symmetric Josephson junction are modeled. A numerical experiment shows that, for the zero interaction coefficient between the layers of the junction, jumps of the critical currents corresponding to different distributions of the magnetic fluxes in the layers may appear on the critical curves. This fact allows a mathematical interpretation of the results of some recent experimental results for two-layered junctions as a consequence of discontinuities of partial critical curves.  相似文献   
2.
A pyrolysis—gas chromatographic (Py—GC) method for the determination of the antioxidant Alurofen in synthetic rubbers was developed. The Alurofen was extracted from the rubber, then pyrolysed as 873 K in continuous-mode furnace pyrolyser in 20 s. Chromatographic conditions for the separation of the pyrolysis products were established. The pyrolysis of the Alurofen at several temperatures was investigated by measuring the yields of the pyrolysis products. It was observed that 2-phenyl-2-(4-hydroxyphenyl)propane was produced in the greatest, amounts, and the effect of the pyrolysis temperature on the yield of this compound was studied. The overall Py—GC method for the determination of the Alurofen content of rubbers had a mean relative error of 2.7% and a relative standard deviation of 2.94%.  相似文献   
3.
HDS catalysts were prepared by loading H3PMo12O40 or H4PMo11V1O40 polyoxometallates on TiO2 (0.5 and 1.0 mmol (Mo+V)). Activity of the catalysts was tested in the HDS of thiophene. The activity of catalysts of low concentration was 2–3 times higher than the activity of those of high concentration. Temperature programmed reduction (TPR) and IR spectroscopy were used to determine the properties of the catalyst. TPR measurements proved that vanadium promotes and stabilizes HDS activity due to an increase in the Mo5+/Mo4+ ratio.  相似文献   
4.
A new ordinary differential inequality without global solutions is proposed. Comparison with similar differential inequalities in the well‐known concavity method is performed. As an application, finite time blow up of the solutions to nonlinear Klein–Gordon equation and generalized Boussinesq equation is proven. The initial energy is arbitrary high positive. The structural conditions on the initial data generalize the assumptions used in the literature for the time being. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
5.
The galvanic behavior of a hollow cathode discharge versus an external weak magnetic field is investigated. The application of this field leads to disordering of the self-aligned states, which is detected as a resonance in the discharge current, named the magneto-galvanic signal. A correlation magneto-galvanic signal–operating voltage-current point is established and attributed to Penning ionization. The contribution of the metastable Ne I 1 s5 to the magneto-galvanic resonance is also verified.  相似文献   
6.
In situ, reversible coacervate formation within lipid vesicles represents a key step in the development of responsive synthetic cellular models. Herein, we exploit the pH responsiveness of a polycation above and below its pKa, to drive liquid–liquid phase separation, to form single coacervate droplets within lipid vesicles. The process is completely reversible as coacervate droplets can be disassembled by increasing the pH above the pKa. We further show that pH-triggered coacervation in the presence of low concentrations of enzymes activates dormant enzyme reactions by increasing the local concentration within the coacervate droplets and changing the local environment around the enzyme. In conclusion, this work establishes a tunable, pH responsive, enzymatically active multi-compartment synthetic cell. The system is readily transferred into microfluidics, making it a robust model for addressing general questions in biology, such as the role of phase separation and its effect on enzymatic reactions using a bottom-up synthetic biology approach.  相似文献   
7.
The process e + e ? → η′γ, η′ → η π0π0, η → γγ is investigated by an SND detector in experiment on a VEPP-2M equipment with colliding electron-positron beams. The analysis of experimental data yields a value of B(? → η′γ)=(6.7 ?4.2 +5.0 ±1.5)×10?5 for the decay probability. Taking into account a previous measurement of this quantity by an SND detector in the decay channel η′ → π+π?η, one finally obtains B(?→η ′γ)=(6.7 ?2.4 +2.8 ±0.8)×10?5.  相似文献   
8.
Physics of Atomic Nuclei - The process $$e^{+}e^{-}\to\eta\pi^{0}\gamma$$ is studied in the range of center-of-mass (c.m.) collision energies between 1.05 and 2.00 GeV on the basis of data...  相似文献   
9.
Physics of Atomic Nuclei - In an experiment with the SND detector at the VEPP-2000 $$e^{+}e^{-}$$ collider, the cross sections for the processes $$e^{+}e^{-}\to K^{+}K^{-}\pi^{0}$$ and...  相似文献   
10.
We study the interaction of alkali metal chlorides with lipid vesicles made of palmitoyloleoylphosphatidylcholine (POPC). An elaborate set of techniques is used to investigate the binding process at physiological conditions. The alkali cation binding to POPC is characterized thermodynamically using isothermal titration calorimetry. The isotherms show that for all ions in the alkali group the binding process is endothermic, counterintuitively to what is expected for Coulomb interactions between the slightly negatively charged POPC liposomes and the cations. The process is entropy driven and presumably related to the liberation of water molecules from the hydration shells of the ions and the lipid headgroups. The measured molar enthalpies of the binding of the ions follows the Hofmeister series. The binding constants were also estimated, whereby lithium shows the strongest affinity to POPC membranes, followed by the rest of the ions according to the Hofmeister series. Cation adsorption increases the net surface potential of the vesicles as observed from electrophoretic mobility and zeta potential measurements. While lithium adsorption leads to slightly positive zeta potentials above a concentration of 100 mM, the adsorption of the rest of the ions mainly causes neutralization of the membrane. This is the first study characterizing the binding equilibrium of alkali metal chlorides to phosphatidylcholine membranes at physiological salt concentrations.  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