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101.
102.
从菲涅耳衍射积分的一般形式出发,结合二维(2D)移相光栅掩模(PSGM)的具体参数,通过数值计算得到了作用于样品表面的光强分布.实验上,采用激光干涉晶化的方法,利用周期为400 nm的2D-PSGM调制KrF准分子激光器的脉冲激光束斑的能量分布,在氢化非晶硅(a-Si:H)薄膜上直接制备了2D的有序纳米硅(nc-Si)阵列.测试结果表明:2D的nc-Si阵列的周期和PSGM的相一致,晶化区域与理论模拟的结果符合得很好.
关键词:
纳米硅
激光干涉晶化
移相光栅
菲涅耳衍射 相似文献
103.
We perform a first-principles simulation to study the electronic and optical properties of wurtzite Zn1 xCuxO.The simulations are based upon the Perdew-Burke-Ernzerhof form of generalised gradient approximation within the density functional theory.Calculations are carried out in different concentrations.With increasing Cu concentration,the band gap of Zn1 xCuxO decreases due to the shift of valence band.The imaginary part of the dielectric function indicates that the optical transition between O 2p states in the highest valence band and Zn 4s states in the lowest conduction band shifts to the low energy range as the Cu concentration increases.Besides,it is shown that the insertion of Cu atom leads to redshift of the optical absorption edge.Meanwhile,the optical constants of pure ZnO and Zn0.75Cu0.25O,such as loss function,refractive index and reflectivity,are discussed. 相似文献
104.
YAO Zhong-Yuan LU Xiang-Yang ZHANG Bao-Cheng QUAN Sheng-Wen HE Eei-Si ZHAO Kui 《中国物理C(英文版)》2010,34(5)
Mechanical errors can not be avoided in fabrication. They will cause geometry errors and have impacts on the cavity performance. This paper systematically analyzes the impacts of mechanical errors on the RF performance of Peking University single spoke cavity. The various kinds of shape and size errors are considered, the influences on the resonation frequency and field flatness are studied by numerical simulation and the theoretical models are analyzed. The results show that the single spoke cavity is robust with respect to the mechanical tolerance. It also indicates the most essential factors for fabrication. 相似文献
105.
基于经典热力学理论,对a-SiNx/a-Si:H/a-SiNx三明治结构或a-Si:H/a-SiNx多层膜结构中纳米硅成核,以及从球形到鼓形的生长过程进行了研究. 建立了限制性晶化理论模型:在纳米硅生长过程中,由于界面能增大将导致生长停止,给出限制性晶化条件——a-Si:H子层厚度小于34 nm. 在激光晶化和常规热退火两种方法形成的a-SiNx/nc-Si/a-SiNx三明治结构和nc-Si/a-SiNx多层膜结构中验证了该理论模型.
关键词:
非晶硅
纳米硅
激光辐照
结晶 相似文献
106.
利用结合移相光栅掩模 (PSGM) 的激光结晶技术在超薄a-SiNx/a-Si:H/ a-SiN x三明治结构样品中制备出二维有序分布的纳米硅阵列.原始样品是用等离子体 增强化学气相淀积法生长.a-Si:H层厚为10nm,a-SiNx 为50nm,衬底材料为SiO 2/Si或 熔凝石英.原子力显微镜、剖面透射电子显微镜、高分辨透射电子显微镜对样品表面形貌和 微结构的观测结果表明,采用该方法可以在原始淀积的a-Si:H层中得到位置可控的晶化区域 :每个晶化区域直径约250nm,具有同PSGM一致的2μm周期;晶化区域内形成的纳米硅 颗粒尺寸接近原始淀积的a-Si:H层厚,且晶粒的择优取向为<111>.
关键词:
纳米硅
激光结晶
定域晶化
移相光栅 相似文献
107.
108.
Atomistic molecular dynamics simulations have are used to investigate the liquid crystal systems based on [4-pentyl-(1-cyclohexenyl)]-(4-cyanophenyl)diazene (5CPDCN) and 4-cyano-4'-pentylazobenzene (5AZCN). The results show the growth process of a nematic phase from a disordered phase. Then the phase transition caused by isomerization reaction is studied based on a temporary modification of the dihedral potential. The properties of 5AZCN and 5CPDCN are compared, showing that the orientation of trans-5CPDCN is more highly ordered than trans-5AZCN. This can be attributed to the more extended dihedral angles φ(2) (i.e. the dihedral angle between the ring system and the terminal chain) in trans-5CPDCN enhance the rod-like conformation of the molecules. The orientational correlation functions g(l)(r) (l = 1, 2) are also calculated, by which we find that both 5CPDCN and 5AZCN systems in nematic phase present parallel and anti-parallel dipole correlations. The anti-parallel dipole correlation is localized for the 5CPDCN system; on the contrary, the parallel dipole correlation is weakly localized for the 5AZCN system. 相似文献
109.
We construct the phase diagram of spherical particles interacted with harmonic repulsions, which are ultrasoft and bounded at fully overlapping. This simple potential form can be used for describing the thermodynamic properties and dynamic behavior of interpenetrable globular micelles, microgels, starlike polymer solutions, and so on. Using dissipative particle dynamics simulations combined with thermodynamic integration, we compute chemical potentials of fluid phase and a number of crystal structures. In addition to the face-centered cubic and body-centered cubic structures, we also find the tetragonal, hexagonal, orthorhombic, and diamond crystal structures stable for this system. In the phase diagram, we identify multiple re-entrant melting regions and polymorphic transitions between the crystals. 相似文献
110.