全文获取类型
收费全文 | 33篇 |
免费 | 28篇 |
国内免费 | 35篇 |
专业分类
化学 | 40篇 |
晶体学 | 1篇 |
物理学 | 55篇 |
出版年
2023年 | 4篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 5篇 |
2013年 | 3篇 |
2012年 | 5篇 |
2011年 | 3篇 |
2010年 | 8篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有96条查询结果,搜索用时 15 毫秒
31.
《发光学报》2021,42(1)
通过有限元分析,利用COMSOL软件模拟计算了Nano-LED半极性面InGaN/GaN单量子阱距离边缘不同位置的应变和压电极化分布,并结合模拟得到的量子阱极化电场,采用Silvaco软件计算得到了Nano-LED InGaN/GaN单量子阱距离边缘不同位置的发光光谱。应变和压电极化分布结果表明,其在距离半极性面量子阱边缘100 nm的范围内变化明显。然而,在半极性面内部,应力释放现象消失,压电极化电场变强,量子限制Stark效应导致InGaN/GaN单量子阱发光强度降低。发光光谱分析表明,60 mA工作电流下,Nano-LEDInGaN/GaN半极性面量子阱边缘位置的光谱峰值最大蓝移达21 nm,其原因在于边缘的应力释放作用。Nano-LED非极性面和半极性面的整体光谱分析表明,在固定Nano-LED高度条件下,Nano-LED的直径越大,半极性面占比越高,器件整体发光光谱的双峰值现象越明显,这将为多波长Nano-LED器件的设计提供借鉴。 相似文献
32.
我们分别运用了传统AMBER03力场以及极化力场研究了EK多肽在不同离子浓度和pH值条件下的折叠.其中极化力场源于我们近期发展的可调的氢键专一性电荷方案.这两种力场的差别仅仅在于原子电荷的不同.溶剂化效应用推广的波恩模型描述.结果表明,当使用AMBER03电荷时,尽管多肽倾向于形成螺旋结构,但是对离子浓度和pH值的依赖关系定性上是错误的.而当使用可调的氢键专一性电荷方案时,EK多肽在10ns内就达到了折叠态.在高离子浓度或者极端pH条件下,计算得到的螺旋结构的概率降低.对于原子电荷以及主链氢键相互作用的分析表明极化效应增加了螺旋结构的稳定性.该研究结果再一次证明了静电极化效应对提高传统力场的精度以及对蛋白质折叠的研究都是非常必要的.进一步的分析说明,间隔4个残基的盐桥作用虽然对稳定蛋白质结构起到了一定的效果,但并不是关键作用,这和实验是吻合的. 相似文献
33.
The polarization state is modulated by tilting birefringence component placed in the feedback external cavity.The variation of the polarization state in one period of modulation is found to be similar to sine wave.The periods become increasingly smaller.The maximum of variation in one period decreases against the rotated angle.The experimental phenomenon is subjected to the change of optical path and secondary reflection.The phenomenon is analyzed theoretically based on geometrical optics and crystal optics.High-accuracy measurements of absolute and relative angles can be realized based on the experimental phenomenon.The angle resolution is 0.1 arcsec in theory. 相似文献
34.
^The polarization effect on the spin symmetry for anti-Lambda spectrum in 16 O+Λ system has been studied in relativistic mean-field theory.The PK1 effective interaction is used for nucleon-meson couplings and G-parity symmetry with a reduction factor ξ = 0.3 is adopted for anti-Lambda-meson couplings.The energy differences between spin doublets in the anti-Lambda spectrum are around 0.10-0.73 MeV for p Λ state.The dominant components of the Dirac spinor for the anti-Lambda spin doublets are found to be near identical.It indicates that the spin symmetry is still well-conserved against the polarization effect from the valence antiLambda hyperon,which leads to a highly compressed cold nucleus with the central density up to 2 - 3 times of saturated density. 相似文献
35.
A pixel array CdZnTe imaging system, employing a 40 × 40× 5 mm^3 pixellated CdZnTe detector, is established. The imaging polarization effect in the CdZnTe pixellated detector for a collimated CS137 Gamma source is investigated in detail. The experimental results for different irradiated fluxes indicate that excessive irradiated flux indeed causes central pixels to be shut off completely. The imaging performance of the polarized detector is severely degraded. Polarized detector counts are simultaneously reduced to one-third of the non-polarized detector counts. A theoretical model of potential distribution is also proposed by solving the Poisson equation and, in turn, the electric potential distortion for high irradiated flux is discussed by comparison with the experimental results. 相似文献
36.
37.
38.
Both fast triangle-wave potential sweep method and fast square-wave potential sweep method have been applied to study transient behavior of the functional polymer membrane chloride electrode. On the basis of current-time curve and potential-time curve, the electrochem. parameters of the electrode were calculated successfully under various conditions. The characterization of the level of ion transfer has been made by means of electrochem. polarization resistance Rr which is related not only to the membrane composition and its shape (area etc.), but also to concentration of the chloride ions in solution The Rr values calculated from both methods are the same. Cl- in the concentration range of 10-4-10-1 mol/L showed linear relation between i and log c, where c is the concentration The slope is proportional to the membrane area. 相似文献
39.
40.