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《Superlattices and Microstructures》2000,27(5-6)
A genetic algorithm approach is used to fit orbital interaction energies of sp3s* tight-binding models for the nine binary compound semiconductors consistent of Ga, Al, In and As, P, Sb at room temperature. The new parameters are optimized to reproduce the bandstructure relevant to carrier transport in the lowest conduction band and the highest three valence bands. The accuracy of the other bands is sacrificed for the better reproduction of the effective masses in the bands of interest. Relevant band edges are reproduced to within a few meV and the effective masses deviate from the experimental values typically by less than 10%. 相似文献
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根据Mie散射理论,对磷化稼粒子光散射特性进行了数值计算与理论分析,得到了散射强度与散射角、入射波长以及偏振度与散射角的关系。研究表明,红外波段光散射很小,前向散射占有优势,粒子半径越大,前向散射越强,并且在散射角900方向上能观测到线偏振光,对研究GaP红外光学特性提供了理论参考。 相似文献
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The structural, electronic and optical properties of GaP, BP binary compounds and their ternary alloys Ga1?xBxP (, 0.5 and 0.75) have been studied by full-potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT) as implemented in WIEN2k package. Local density approximation (LDA) and generalized gradient approximation (GGA) as proposed by Perdew–Burke–Ernzerhof (PBE), Wu–Cohen (WC) and PBE for solid (PBESol) were used for treatment of exchange-correlation effect in calculations. Additionally, the Tran–Blaha modified Becke–Johnson (mBJ) potential was also employed for electronic and optical calculations due to that it gives very accurate band gap of solids. As B concentration increases, the lattice constant reduces and the energy band gap firstly decreases for small composition x and then it shows increasing trend until pure BP. Our results show that the indirect–direct band gap transition can be reached from . The linear optical properties, such as reflectivity, absorption coefficient, refractive index and optical conductivity of binary compounds and ternary alloys were derived from their calculated complex dielectric function in wide energy range up to 30 eV, and the alloying effect on these properties was also analyzed in detail. 相似文献
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报道了利用脉宽可调的光子晶体光纤飞秒激光放大器抽运矩形波导结构的GaP晶体太赫兹(THz) 发射器产生频率可调谐的超快THz脉冲.非线性晶体中光整流过程产生的THz辐射频率随抽运光脉冲宽度而 变化. GaP波导THz发射器可通过波导的几何尺寸来控制色散,以达到增加有效作用长度和提高输出功率的目的. 不同横截面尺寸的波导型发射器的THz辐射峰值频率随相位匹配条件的改变而改变,加以脉宽调节技术, 可以在大频谱范围获得频谱精细可调的THz脉冲.实验中在1 mm×0.7 mm的波导型THz发射器中获得了 频率可调谐的THz脉冲.提出实现THz辐射频率大范围调谐的GaP波导型阵列发射器的实施方案. 相似文献
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Takenori Tanno Ken Suto Yutaka Oyama Jun-Ichi Nishizawa 《Journal of Electronic Materials》2003,32(3):172-175
The effects of substrate pre-annealing on deep level density in Mg-doped GaP liquid-phase epitaxy (LPE) layers were investigated
by photocapacitance measurement. With annealing under optimum phosphorus-vapor pressure, concentration of deep donor at EC — 1.9–2.1 eV increased in undoped GaP substrate. Deep level densities in Mg-doped layers were also affected by pre-annealing
of the substrates. Densities of dominant deep levels at EV + 0.85 eV and EV + 1.5 eV were an order of magnitude reduced and, in contrast, the level at EC − 2.1 eV in Mg-doped layer increased with long pre-annealing. This level at EC − 2.1 eV is supposed to be involved with P-rich-type nonstoichiometric defects, such as phosphorus interstitial atoms diffused
from the surface of the substrate. 相似文献
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测量了GaP纯绿发光二极管老化前后的可见和近红外发光光谱,研究了老化产生的深能级的来源及其对二极管发光效率的影响.在老化后的发光光谱中观测到650nm和1260nm发光带,发现1260nm发光带的发光强度随老化时间的增加而增强.实验结果表明老化产生的与磷相关的深能级严重地影响了GaP纯绿LED的发光效率. 相似文献