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41.
A Multilayered Configuration Broadband Polarization Insensitive Reflector Utilizing a Multi-Subpart Profile Grating Structure
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A multilayered configuration broad bandwidth polarization insensitive reflector realized by a multi-subpart profile grating structure is presented. The properties of the reflector are investigated by rigorous coupled-wave analysis. It is shown that over a broadband spectrum of 1.62-1.76μm, the reflector demonstrates high reflectivity (R 〉 99%), low polarization-dependent loss (PDL〈 0.02 dB) and good angular insensitivity of about 29.6% for both transverse electric and transverse magnetic polarized waves. 相似文献
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双核铜酶模型的合成及对安息香的催化氧化 总被引:2,自引:0,他引:2
为寻求更有效的仿酶模型,本文设计合成了含四个咪唑配基、两个咪唑基与铜配位的新型双核铜酶模型,并实现了在氧气存在下模型对安息香的催化氧化作用。以邻-氯苯酚为原料,经直接咪唑甲基化,醚化偶联,继与[Cu(CH~3CN)~4]CLO~4反应合成目标酶模型6-8。类似地,由对-氯苯酚合成酶模型9。以机械7为例,研究了在氧气下它们催化氧化安息香为二苯乙二酮的反应,高产率地合成目标产物,并求得催化氧化反应动力学参数。考查不同催化剂对反应的影响,发现它们的活性次序如下:7>4+[Cu(CH~3CN)~4]ClO~4>[Cu(CH~3(CN)~4]ClO~4>2+[Cu(CH~3CN)~4]ClO~4。 相似文献
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Syndiotactic polystyrene (sPS) and polyamide-6 (PA6) are immiscible and incompatible and have been recognized. In this study, sulfonated syndiotactic polystyrene (SsPS-H) is employed as compatibilizer in the blend of sPS/PA6. During melt blending, the sulfonic acid groups of the SsPS-H can interact strongly with the amine end-groups of PA6 through acid-base interaction. In addition, SsPS-H is miscible with sPS when SsPS-H content is less than 20 wt.%. Therefore, the addition of SsPS-H to sPS/PA6 blends reduces the dispersed phase size and improves the adhesion between the phases. The glass transition temperatures of the PA6 component in the compatibilized blends shift progressively towards higher temperature with the content of SsPS-H-12 increase, indicating enhanced compatibility. On the other hand, the progressive lowering of the melting point and crystallization temperatures of PA6 in the blends with increasing SsPS-H contents compared to the incompatibilized blend, provide some insight into the level of interaction between the PA6 and SsPS-H. The compatibilized blends have significantly higher impact strength than the blends without SsPS-H. The best improvement in the impact strength of the blends was achieved with the content of the SsPS-H (11.9 mol%) about 5 wt.%. 相似文献
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Shuang-Kou Chen Bo-Chu Wang Tai-Gang Zhou Ying-Zhu Feng Hua-Ming Liang Wen-Zhang Huang 《Colloids and surfaces. B, Biointerfaces》2009,70(2):243-247
Adhesive proteins secreted by the marine mussel could bind strongly to all kinds of surfaces, for instance, ship hulls and petroleum pipelines. Studies indicated that there was an unusual amino acid 3,4-dihydroxy-l-phenylanine (dopa), which was the crucial super adhesive unit in the proteins. The technology of electrolyzing seawater was employed to generate HOCl solution to hinder the adhesion. However, the detailed anti-fouling mechanism of HOCl solution remained unknown to be fully explained. Herein, we theoretically reported a study of single molecular (dopa) reaction under the HOCl solution environment, which would be helpful to reveal the anti-fouling mechanism through electrolyzing seawater. By using the density functional theory (DFT) quantum mechanics procedure, we theoretically studied the reaction mechanism of the adhesive unit dopa in mussel with electrolyzing seawater. Two possible pathways (1 and 2) were obtained (Fig. 6). The transition state for each pathway was determined, the intrinsic reaction coordinate (IRC) was analyzed and the mechanism had been confirmed. The calculations indicated dopa tended to have electrophonic attacking substitution reaction to generate 3-chlorine-4,5-dihydroxyphenylalanine (dopa-Cl) with different pathways, which hindered the formulation of conjuncted dopa–dopa and thus the stickiness among mussel adhesive proteins reduced. The transition states computation showed that pathway (1) had one transition state (TS1-1) with an activation energy of 102.22 kJ mol−1, while pathway (2) had two transition states (TS2-1, TS2-2) with activation energies of 191.98 kJ mol−1 and 42.00 kJ mol−1 respectively and one intermediate (IM2-1). Rate constant value of pathway (1) was much bigger than that of pathway (2) regardless of high or low temperature, which meant that in the reaction process, pathway (1) was the favorable reaction step; but as the temperature rose, the competitiveness of pathway (2) gradually increased. After the theoretical calculation, we found that it was Cl+ played an important and direct role in the dopa's modification. 相似文献
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The local structure and spin Hamiltonian parameters (the g factors and the hyperfine structure constants) for the orthorhombic Cu2+ center in LiNbO3 are theoretically studied from the perturbation formulas of these parameters for a 3d9 ion in an orthorhombically elongated octahedron. This center is ascribed to Cu2+ occupying the Nb5+ site in LiNbO3, associated with one nearest neighbour oxygen vacancy VO along the Z axis. The planar bond lengths are found to suffer the relative variation of about 0.16 Å by compressing and stretching the Cu2+–O2? bonds along the X and Y axes, respectively, due to the Jahn–Teller effect and the charge mismatching substitution of Nb5+ by Cu2+. Meanwhile, the effectively positive VO can make the central Cu2+ displace away from the VO along the Z axis by about 0.3 Å. The theoretical spin Hamiltonian parameters based on the above local distortions show good agreement with the experimental data. 相似文献