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11.
L. Ward 《Optics & Laser Technology》2002,34(7):3280
Contour graphs of 2 vs 4 for different film thicknesses and a range of angles of incidence have been plotted for the ellipsometric functions Δ and Ψ in both the reflection and transmission modes. In the case of reflection ellipsometry, when the plots for ΔR and ΨR are superimposed, the two sets of contours cross nearly at right angles over a large part of the field, this being indicative of the high accuracy obtainable in using this technique to determine 4 and 2 and hence the optical constants, n and k, for the film material. The reflection ellipsometric technique is accurate over angles of incidence between 30° and 75° and for a range of film thicknesses between λ/30 and 5λ. Transmission ellipsometry is less useful, due to anomalies in both Xs and Xp where sudden phase changes of ±π occur in regions of interest. There is also the possibility of multiple solutions, although the use of a multiangle technique would enable the “correct” values to be more easily determined. 相似文献
12.
Studies of the behaviour with 1, 2 and film thickness of the optical functions reflectance (R) and phase change on reflection (Φr) have previously been made for both very thin and very thick films. Abelès [J. Opt. Soc. Amer. 47 (1957) 473] has formulated equations for very thin films where functions of 1 and 2 are the coefficients of a power series of the optical thickness, x(2πd/λ) up to x2, whilst in the case of very thick films (solids) the relationships between 1 and 2 can be represented in polar coordinates L and α by 1=L cos α, 2=L sin α where LR=2y20W2(1+cos α−1/W2) [W=(1+R)/(1−R)] and LΦr=2(y0/ tan Φr)2(1−cos α+tan 2 Φr) [Ward, Opt. and Laser Tech. 27 (1995) 125]. The present study is concerned with films of intermediate optical thicknesses (1.0<2πd/λ<solid) and has revealed that the polar-type relationships previously noted for solid materials are augmented by secondary structures of maxima and minima whose position and amplitude can be predicted by adapting the exact equations for R and Φr. 相似文献
13.
14.
土壤砷含量高光谱估算模型研究 总被引:2,自引:0,他引:2
以实验室内测取的土壤反射光谱为研究对象,利用PLSR方法建立反射光谱与土壤As含量之间的模型,通过交叉验证、估算检验建模精度,探讨利用反射光谱估算士壤As含量的可行性.通过比较不同光谱预处理方法、不同光谱分辨率和不同OM含量条件下建模、验证和估算结果.表明,MSC方法可以有效去除散射的影响而取得较好的结果(估算R2=0... 相似文献
15.
Roozbeh HajiraissiMazeyar Parvinzadeh 《Applied Surface Science》2011,257(20):8443-8450
Influence of nanosilica on surface properties of poly(butylene terephthalate) was investigated by the use of Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), contact angle measurement (CAM), scanning electron microscopy (SEM) and reflectance spectroscopy (RS). FTIR results indicated that surface groups of silica have some interfacial interactions and bonding with carboxyl or hydroxyl end groups of PBT chains. AFM and SEM figures of the resultant nanocomposites illustrated increased surface roughness compared to pure PBT. Optical properties of nanocomposite films were finally determined by the aid of reflectance spectrophotometer. 相似文献
16.
A new spectrophotometer design permits simultaneous measurement of color and surface appearance attributes of reflecting specimens. The new design provides a multi-channel spectrometer that is simple, compact, light, and inexpensive, while having a unique combination of features and performance. Novel d/8° geometry provides new capabilities. With a single quick measurement, the instrument measures color and several other appearance attributes. A concentric optical configuration used for the spectrometer eliminates third-order optical aberrations. The optical design and unique features are described and performance data are presented. 相似文献
17.
Si was deposited on the glass substrate as an interlayer for the 2-D growth of Ag thin films because Si has a strong binding energy against Ag and can lead to a negative surface energy change in Ag/glass. The Si interlayer induced an extremely smooth and flat Ag surface, which effectively reduced the resistance and enhanced the reflectance in the IR region. In particular, Ag (9 nm)/Si (3 nm)/glass showed 0.074 emissivity and ∼91% reflectance in the IR region with 67% transmittance in the visible region. 相似文献
18.
A complete inspection of the capabilities of reflectance anisotropy spectroscopy (RAS) in studying the adsorption of molecules or atoms on the Si(0 0 1)-(2 × 1) surface is presented. First, a direct comparison between RA spectra recorded on the clean Si(0 0 1)-(2 × 1) and the corresponding topography of the surface obtained using scanning tunneling microscopy (STM) allows us to quantify the mixing of the two domains that are present on the surface. Characteristic RA spectra recorded for oxygen, hydrogen, water, ethylene, benzene are compared to try to elucidate the origin of the optical structures. Quantitative and qualitative information can be obtained with RAS on the kinetics of adsorption, by monitoring the RA signal at a given energy versus the dose of adsorbate; two examples are presented: H2/Si(0 0 1) and C6H6/Si(0 0 1). Very different behaviours in the adsorption processes are observed, making of this technique a versatile tool for further investigations of kinetics. 相似文献
19.
Using real-time, dynamic reflectance anisotropy spectroscopy (RAS) at both 2.6 eV and 4.0 eV, we demonstrate that an anisotropic oxide will form on As rich c(4 × 4)/d(4 × 4) GaAs surfaces when exposed to moisture- free air diluted in inert gases in a metal organic chemical vapour deposition (MOCVD) reactor, and that the initial c(4 × 4)/d(4 × 4) structure effects the resulting optical anisotropy of the oxide. This was achieved by investigating how the RA signals at 2.6 eV and 4 eV of annealed GaAs (1 0 0) surfaces evolve relative to the as-etched and as-annealed signals when exposed to oxygen. It is found that while the 2.6 eV response, which is known to be associated with the As dimers, degrades to pre-process levels indicating their destruction, the 4 eV signal, stabilizes at an intermediate, permanent level, suggesting the formation of an anisotropic oxide film whose structure is determined at least in part, by the initial c(4 × 4)/d(4 × 4) surface. 相似文献
20.
In the present work HCl-isopropanol treated and vacuum annealed InP(0 0 1) surfaces were studied by means of low-energy electron diffraction (LEED), soft X-ray photoemission (SXPS), and reflectance anisotropy (RAS) spectroscopies. The treatment removes the natural oxide and leaves on the surface a physisorbed overlayer containing InClx and phosphorus. Annealing at 230 °C induces desorption of InClx overlayer and reveals a P-rich (2 × 1) surface. Subsequent annealing at higher temperature induces In-rich (2 × 4) surface. The structural properties of chemically prepared InP(0 0 1) surfaces were found to be similar to those obtained by decapping of As/P-capped epitaxial layers. 相似文献