全文获取类型
收费全文 | 97篇 |
免费 | 1篇 |
专业分类
化学 | 45篇 |
晶体学 | 10篇 |
力学 | 1篇 |
数学 | 10篇 |
物理学 | 32篇 |
出版年
2021年 | 2篇 |
2018年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 2篇 |
2005年 | 6篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有98条查询结果,搜索用时 31 毫秒
91.
A. Usami 《Optical and Quantum Electronics》1976,8(1):15-22
The effects of Cu-doping, oxygen and dopant on the fast neutron radiation damage of silicon solar cells are studied in this paper. The diffusion length damage coefficientK
L is defined as KL= (1/L
i
2
– 1/L
o
2
)–1= (1/L2)–1. The (1/L2) values of n/p-type cells, measured at 300 and 80K, are smaller by about one order in magnitude than those of p/n-type cells. Characteristic curves of (1/L
2) values versus total neutron flux of p/n, n/p and copper-doped n/p-type cells begin to deviate from a 45° straight line around a total neutron flux of 1012 to 1013 n cm–2. The effect of copper-doping on the radiation resistant property is observed with high resistivity bulk n/p-type (20 to 40 -cm) cells, but not with low resistivity bulk n/p-type (10 -cm) cells at 300K. Values of (1/L
2) versus neutron flux, measured at 80K, are not affected by copper-doping, bulk dopant and oxygen concentration in the bulk region of n/p-type cells. The isochronal annealing of silicon solar cells depends on the total neutron flux, copper-doping and carrier injection during the annealing process. Namely, copper-doping and carrier injection enhance the annealing process of the neutron-induced defect clusters in n/p-type cells. 相似文献
92.
Ion-pair formation constant (KAgPic in mol−1 dm3) of silver picrate (AgPic), those (KAgLPic) of its ion-pair complexes (AgLPic) with crown ethers (L) and complex formation constants (KAgL) of Ag+ with L (15-crown-5 ether (15C5) and benzo-15C5) in water (w) were determined potentiometrically at 25 °C. Compounds used as L were 18-crown-6 ether (18C6), its benzo-derivative (B18C6) and the two 15C5 derivatives. Extraction constants (Kex in mol−1 dm3) of AgPic with L (15C5, 18C6, B18C6) from acidic w-phases into either C6H6 or CHCl3 were recalculated from KAgPic, KAgL, KAgLPic and data opened in previous papers. Thus obtained Kex was divided into five component equilibrium constants containing KAgL and KAgLPic anew. Then, contributions of the component constants, KAgL, KAgLPic and distribution constants of AgLPic between the w- and C6H6-phases, to Kex were discussed and compared with corresponding extraction systems of NaPic and KPic with18C6. 相似文献
93.
Kudo Y Wakasa M Ito T Usami J Katsuta S Takeda Y 《Analytical and bioanalytical chemistry》2005,381(2):456-463
Ion-pair formation constants (mol–1 dm3 unit), KMX for a univalent metal salt (MX) and KMLX for its ion-pair complex (ML+X–) with a crown ether (L) in water, were determined at various ionic strengths (I) and 25°C by potentiometry with ion-selective electrodes for MX=NaPic, NaMnO4, NaBPh4, KPic, and KMnO4; and MLX=Na(18C6)Pic, K(18C6)Pic, and Na(18C6)BPh4, where Pic– and 18C6 denote a picrate ion and 18-crown-6 ether, respectively. Equations for analyzing I-dependence of logKMLX and logKMX were derived and fitted well to the I-dependence using a non-linear regression analysis. The equilibrium constants at I=0 mol dm–3, KMLX° and KMX°, were simultaneously obtained from the analysis. The experimental values of KMLX and KMX were only in agreement with the values calculated from KMLX° and KMX°, respectively, in the ranges of higher I. 相似文献
94.
Südmeyer T Innerhofer E Brunner F Paschotta R Usami T Ito H Kurimura S Kitamura K Hanna DC Keller U 《Optics letters》2004,29(10):1111-1113
We demonstrate a synchronously pumped high-gain optical parametric oscillator with feedback through a fiber, using a passively mode-locked Yb:YAG thin-disk laser as a pump source. We obtain as much as 19-W average signal power at a wavelength of 1.45 microm in 840-fs pulses and 7.8 W of idler power at 3.57 microm. The repetition rate of the pulses is 56 MHz, and the transverse beam quality of the generated signal is M2 < 1.6. 相似文献
95.
We experimentally investigate and compare the effects of copropagating and counterpropagating directions on a semiconductor optical amplifier-Mach-Zehnder interferometer based wavelength converter. When an assist light is not used, the copropagating scheme induces a long rise-fall time and small timing jitter, whereas the counterpropagating scheme induces a short rise-fall time and large timing jitter. The results show that the copropagating scheme with a backward assist light yields the best performance. 相似文献
96.
Kazuo Nakajima Toshihiro Kusunoki Yukinaga Azuma Noritaka Usami Kozo Fujiwara Toru Ujihara Gen Sazaki Toetsu Shishido 《Journal of Crystal Growth》2002,240(3-4):373-381
The effect of the supply of depleted Si solute elements on the compositional variation in the Si-rich SiGe bulk crystals was studied using the method which was used to grow Ge-rich SiGe single crystals with a uniform composition. By selecting the proper pulling rate, we can obtain Si-rich Si1−xGex bulk crystals with uniform composition of x=0.1 without using the supply mechanism of depleted Si solute elements. When the supply mechanism of Si solute elements was used, the initial composition in Si-rich SiGe crystals can be much more easily determined by controlling the growth temperature than that in Ge-rich crystals because the Si seed crystal is not melted down. The supply of Si solute elements is very effective to change the compositional variation even for Si-rich SiGe crystals. 相似文献
97.
98.
Unusual behaviour of the dark conglomerate (DC) phase seen in an oxadiazole-based achiral bent-core liquid crystal, which has not previously been reported for the DC phase of other liquid crystals, is described. Under polarising optical microscopy, we see no domains of opposite handedness in the ground state of the DC phase. However, it shows unusual transformations when an electric field is applied to the system. On increasing the electric field, at first the domains of opposite handedness become visible and then they grow in size and slowly the sample transforms to a monochiral or single-handed form which is followed by a nonchiral state at very high fields. The threshold electric fields required to achieve these changes are temperature dependent and the transformations are seen irrespective of the frequency of the applied electric field (100 Hz to 5 kHz), type of the waveform (sine, square and triangular) and the thickness (1.5 μm to 15 μm) or the geometry (planar and twisted) of the device used. Further, there is no field-induced high birefringence texture observed even though sufficiently large electric field (~22 V/μm) has been applied across the devices. The nature of the behaviour is investigated by various techniques such as optical microscopy, conoscopy, circular dichroic and Raman spectroscopies, electro-optics and dielectric spectroscopy. The possible physical phenomena behind these changes are discussed in detail. 相似文献