全文获取类型
收费全文 | 86篇 |
免费 | 1篇 |
专业分类
化学 | 53篇 |
力学 | 1篇 |
数学 | 5篇 |
物理学 | 28篇 |
出版年
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 7篇 |
2010年 | 2篇 |
2009年 | 9篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 31 毫秒
1.
Results of an experimental observation of the voltage oscillations associated with a discrete tunneling of holes in porous silicon at room temperature are presented. The noise characteristics of diode structures with a porous silicon interlayer formed on heavily boron-doped silicon single crystals are studied. Peaks of excessive noise are observed at frequencies of ~1 MHz, at which single-electron oscillations should be expected. The peak noise power is found to increase with current according to the ~2.5 power law and, at a current density of 0.15 A/cm2, to exceed the noise power of the receiver by three to four orders of magnitude. The complex shape of the noise spectrum and its extension to the higher frequency region with increasing current are explained by the three-dimensionality of the system of nanometer-sized silicon grains embedded in insulating silicon dioxide of porous silicon. 相似文献
2.
Tegos GP Demidova TN Arcila-Lopez D Lee H Wharton T Gali H Hamblin MR 《Chemistry & biology》2005,12(10):1127-1135
Fullerenes are soccer ball-shaped molecules composed of carbon atoms, and, when derivatized with functional groups, they become soluble and can act as photosensitizers. Antimicrobial photodynamic therapy combines a nontoxic photosensitizer with harmless visible light to generate reactive oxygen species that kill microbial cells. We have compared the antimicrobial activity of six functionalized C(60) compounds with one, two, or three hydrophilic or cationic groups in combination with white light against gram-positive bacteria, gram-negative bacteria, and fungi. After a 10 min incubation, the bis- and tris-cationic fullerenes were highly active in killing all tested microbes (4-6 logs) under conditions in which mammalian cells were comparatively unharmed. These compounds performed significantly better than a widely used antimicrobial photosensitizer, toluidine blue O. The high selectivity and efficacy exhibited by these photosensitizers encourage further testing for antimicrobial applications. 相似文献
3.
A. I. Bulavchenko M. G. Demidova P. S. Popovetskiy T. Yu. Podlipskaya P. E. Plyusnin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(8):1493-1501
It is shown by physicochemical means (IR Fourier spectroscopy, CHN-analysis with preliminary sorption of surfactant on SiO2) that the content of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in an electrophoretic concentrate remains unchanged during the electrophoretic concentration of silver and gold nanoparticles. Diluting the concentrate and carrying out the second stage of electrophoresis reduces the concentration of surfactant from 0.25 to 0.015 M while maintaining the mass concentration of nanoparticles. Nanoparticles in organosols before and after electrophoresis are characterized by means of photon correlation spectroscopy, phase analysis light scattering, and spectrophotometry. Conducting films on glass substrates are obtained from concentrates with a different contents of surfactant via water–alcohol treatment and thermolysis. 相似文献
4.
Nikita O. Shaparenko Marina G. Demidova Alexander I. Bulavchenko 《Electrophoresis》2021,42(16):1648-1654
Electrophoretic mobility of SiO2 nanoparticles in a n-hexadecane-chloroform mixture depending on AOT concentration and chloroform content was determined. It was shown that an increase in chloroform content and a decrease in AOT concentration cause a growth in electrophoretic mobility. The use of the values of Debye lengths (characteristic thickness) of the diffuse part of the electric double layer (EDL) that were determined previously allowed us to calculate the electrokinetic potential and to evaluate the stability of organosols. The obtained data were in good correlation with the dynamics of temporal changes of hydrodynamic radius and the intensity of light scattering. Organosols may be used for heteroaggregation (sorption) of Au and Ag nanoparticles on SiO2. 相似文献
5.
6.
7.
M. G. Demidova A. I. Bulavchenko T. Yu. Podlipskaya A. I. Boronin L. S. Kibis V. I. Zaikovskii 《Russian Journal of Inorganic Chemistry》2011,56(8):1199-1207
We have developed methods for the synthesis and coagulation of ultrafine silver powders in the water-Triton N-42-decane inverted-micellar
system. Varying AgNO3 concentration (1–5 mol/L), the type of reducing agent (hydrazine or potassium borohydride), and the coagulation method (spontaneous
or induced by acetone or water addition) allowed us to select the parameters that provide powders containing about 98% silver
and having particle sizes of 15–80 nm. We propose methodology for characterizing ultrafine silver powders comprising the determination
of the total and surface composition and the charge state of impurities using atomic absorption spectroscopy (AAS), atomic
emission spectroscopy (AES), microanalysis, FTIR spectroscopy, and X-ray photoelectron spectroscopy. The impurity composition
of the nanomaterial is found to depend on the type of reducing agent, the synthesis parameters, and coagulation conditions. 相似文献
8.
M. G. Demidova N. O. Shaparenko T. Yu. Podlipskaya A. I. Bulavchenko 《Russian Journal of Inorganic Chemistry》2017,62(6):715-722
Stable SiO2 and TiO2 organosols were prepared by hydrolyzing tetraethyl orthosilicate (TEOS) in the presence of 6–12 M NH3 and titanium(IV) isopropylate (TTIP) in reverse microemulsions of 0.12–0.25 M bis(2-ethylhexyl) sulfosuccinate (Aerosol OT, AOT) in n-decane with the aqueous pseudophase content of 2–3 vol %, 0.018–0.090 M TEOS, and 0.15–0.55 vol %, 0.003–0.025 M TTIP. The degree of hydrolysis was monitored by IR spectroscopy (for TEOS) and spectrophotometry (for TTIP). Oxide nanoparticles were characterized by photon-correlation spectroscopy (PCS) (D h = 8–100 nm) and laser electrophoresis (ζ-potential = 7.4–11.6 mV). The occurrence of surface potential made it possible to separate the oxides from the excess of surfactant by nonaqueous electrophoresis and to determine particle sizes (7–40 nm) by means of transmission electron microscopy (TEM). 相似文献
9.
E. S. Demidov A. N. Mikhaylov A. I. Belov M. V. Karzanova N. E. Demidova Yu. I. Chigirinskii A. N. Shushunov D. I. Tetelbaum O. N. Gorshkov E. A. Evropeitsev 《Physics of the Solid State》2011,53(12):2415-2420
It has been shown that the presence of silicon nanoparticles in a layer of porous silicon saturated with tungsten-tellurite
glass causes an increase in the photoluminescence quantum efficiency of erbium (1530 nm) by an order of magnitude in the case
of long-wavelength excitation and an enhancement of the ytterbium photoluminescence (980 nm) by almost 50 times and erbium
photoluminescence by 25 times in the case of short-wavelength pumping. This luminescence enhancement is explained by the formation
of additional channels of transfer of external excitation by silicon nanocrystallites in porous silicon to impurity ytterbium
and erbium ions in tungsten-tellurite glass. 相似文献
10.
V. I. Albul V. B. Bychkov S. S. Vasil’ev K. E. Gusev V. S. Demidov E. V. Demidova N. K. Krasnov A. F. Kurchanov V. E. Luk’yashin A. Yu. Sokolov 《Acoustical Physics》2005,51(1):33-37
In an experiment with a beam of protons accelerated up to an energy of 200 MeV, the space-time structure of the hydroacoustic field generated by protons stopping in the water medium was observed. The contributions of three components were separated: a cylindrical wave diverging from the middle part of the acoustic antenna and the signals from the ends of the antenna, namely, from the region of the maximal energy density release by protons (the Bragg peak) and from the other end corresponding to the beam entrance into water. 相似文献