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1.
Zinc oxide (ZnO) nano-particles have been synthesized by a matrix-assisted method with various precursors. An activated carbon was used as a matrix and zinc acetate, zinc nitrate, and zinc chloride were selected as precursors. The ZnO nano-particles appeared to be either spherical or elliptical shapes when zinc acetate and zinc nitrate were used as precursors, while those particles became irregular in their shapes when zinc chloride was used as a precursor. The products were characterized by using TGA, XRD, BET, TEM and SEM. A nano-size ZnO was formulated for the effective removal of a very low concentration of sulfur compounds (H2S, COS) contained in a gasified fuel gas and their reactivity was also investigated in this study. Zinc acetate was the best precursor for the formulation of the ZnO nano-particles in the experiment. The size of the formulated ZnO nano-particles was in the range of 10–30 nm and its surface area was about 40.7 m2/g. From TGA (thermal gravity analysis) test, it was found that its sulfur capacity was about 9.27 g S/100 g-sorbent for H2S and 0.56 g S/100 g-sorbent for COS and its initial sulfur absorption rates with H2S and COS absorption were about 257.5 mg S/min · 100 g-sorbent and 15.6 mg S/min · 100 g-sorbent, respectively. Their reactivity increased as their sizes became smaller and their surface areas of the sorbents were larger. Most prepared nano-size ZnO showed an excellent performance for the removal of not only H2S but also COS.  相似文献
2.
The surface fractal dimension was calculated by using a mathematical model and mercury intrusion data for a variety of bi- and multi-disperse porous solids including silica gels, alumina pellets, and building stones. The mathematical model was obtained by modifying the well-established scaling relation published previously [Ind. Eng. Chem. Res., 34 (1995) 1383-1386]. It was also verified by comparing with the theoretical surface fractal dimensions for regular fractal structures (Skerpinski tetrahedron and Menger sponge) and the calculated surface fractal dimensions for silica gel and alumina particles via the linear fitting method established previously. The calculation results for various bi- and multi-disperse porous solids have demonstrated that the scale-dependent nature of the surface fractal dimension is ubiquitous. The difference in the surface fractal dimension between pore size intervals usually exists. The estimation of the surface fractal dimension on an average stand may lead to erroneous results.  相似文献
3.
掺杂Er^3+的TiO2的发射光谱研究   总被引:1,自引:1,他引:0  
用无水乙醇、冰醋酸、钛酸丁酯凝胶法制备了掺杂Er^3+的TiO2粉末,测量了其在488m激发下的Stokes发射光谱和980nm激发下的上转换发光光谱。在可见光范围内,观察到了绿光和红光,绿光从500-570nm,对应Er^3+的^2H11/2,^4S3/2→^4I15/2,红光从650~690m,对应Er^3+的^4F9/2→^4I15/2的跃迁。由ln Ivis-In Iin曲线可知,绿光和红光均为双光子过程,光强正比于泵浦功率的二次方,即Iout ∝Iin。初步研究了此材料的上转换过程。  相似文献
4.
PbSe量子点在太阳能荧光聚集器中的应用研究   总被引:1,自引:0,他引:1  
将PbSe量子点成功引入到了太阳能荧光聚集器(LSC)的应用中,利用光子追踪的方法,成功建立了一种基于Monte Carlo模拟方法的模型,通过实验测量,得到PbSe量子点相关数据,在这些数据基础上,对PbSe量子点LSC的各个参数进行模拟优化,并在优化的条件下,对基于PbSe量子点LSC对太阳能电池单位输出能量造价进行考察,发现通过PbSe量子点LSC的引入,太阳能电池的造价可以降低49.2%,说明PbSe量子点非常适用于LSC体系。  相似文献
5.
Fluorescent properties of novel dendrimer dyes based on thiazole orange   总被引:1,自引:0,他引:1  
In this paper, polyamidoamine (PAMAM) dendrimers with active amino group of some generations (G=0.5-2) were prepared from commercial aminoacetaldehyde diethyl acetal by the divergent method. After that, thiazole orange (TO) with -COOH was incorporated with dendrimers of G=1 and 2 to afford novel dendrimer-TO dyes. The fluorescent properties studies showed that the fluorescent intensity of the same concentration of dendrimer-TO (G=2) was higher than that of the dendrimer-TO (G=1), and both of them were much stronger than free TO with -COOH. There was a fluorescent enhancement of the dendrimer dyes compared with free dye. The dendrimer dyes were of well-defined chemical structure,with little aggregation and self-quenching as well as good fluorescence properties of good stability, high intensity and sensitivity, which could be used in labeling cancer cells and further in diagnosis and detection of early-stage tumors.  相似文献
6.
Hollow black TiO nanosparticles were obtained via deposition of inorganic coating on the surface of hollow core-shell polymer latex with Ti(OBu)4 as precursor and subsequent calcination in ammonia gas. Hollow TiO particles were characterized by scanning electron microscope, transmission electronic microscopy, X-ray diffraction, and thermogravimetric analysis. Encapsulation of TiO via dispersion polymerization was promoved by pretreating the pigments with 3-(trimethoxysilyl) propyl methacrylate, making it possible to prepare hollow TiO-polymer particles. When St and DVB were used as polymerization monomer, hollow TiO-polymer core-shell particles came into being via dispersion polymerization, and the lipophilic degree is 28.57%. Glutin-arabic gum microcapsules containing TiO-polymer particles electrophoretic liquid were prepared using via complex coacervation. It was founded that hollow TiO-polymer particles had enough electrophoretic mobility after coating with polymer.  相似文献
7.
Activated phenol resin-based carbon spheres (APCS) electrodes with high double layer capacitance and good rate capability were prepared from phenol resin-based spheres (PS) at different carbonization temperatures prior to KOH activation. The carbonization temperature has a marked effect on both the pore structure and the electrochemical performances of the APCS in 6 M KOH electrolyte. APCS carbonized at 600 °C results in higher specific surface area and larger pore size, and hence higher capacitance and better rate capability. The specific capacitance of the APCS in 6 M KOH aqueous solution can be as high as 282 F g−1. It remains 252 F g−1 as the current density increases to 1000 mA g−1.  相似文献
8.
The technology of high-energy irradiation is widely used in the field of material interface modification because of its high efficiency, energy conservation and environment friendliness. In this paper, γ-ray irradiation graft technology was used in order to enhance the surface performance of the carbon fibre (CF). The surface chemical elements and functional groups of untreated and irradiated CF were observed by photoelectron spectroscopy (XPS). The results show that the value of O/C and the quantity of oxygen functional groups on CF surface were enhanced efficiently after treatment by γ-ray irradiation graft technology. The morphology of CF was characterized by scanning electron microscopy (SEM) and atom forced microscopy (AFM), respectively. The surface roughness of CF was greatly increased compared with the untreated CF. Moreover, the interface performance was clearly improved after irradiation.  相似文献
9.
Potato starch-based activated carbon spheres (PACS) were prepared from potato starch by stabilization, carbonization followed by activation with KOH. The obtained PACS are hollow and retain the original morphology of potato starch with decrease in size, as shown by scanning electron microscopy. Modification of textural properties of the PACS was achieved by varying the carbonization temperature and the ratio of KOH/PCS. The results of N2 adsorption isotherms indicate that the samples prepared are mainly microporous. The electrochemical behaviors of the hollow PACS were studied by galvanostatic charge-discharge, cyclic voltammetry, and impedance spectroscopy. The results indicate that high specific capacitance of 335 F/g is obtained at current density 50 mA/g for PACS with specific surface area 2342 m2/g. Only a slight decrease in capacitance, to 314 F/g, was observed when the current density increases to 1000 mA/g, indicating a stable electrochemical property.  相似文献
10.
Superhydrophobic surfaces based on dandelion-like ZnO microspheres   总被引:1,自引:0,他引:1  
This study presents a simple method to fabricate superhydrophobic surface based on ZnO nanoneedles. ZnO nanoneedles had been constructed on zinc layers by immersing in an aqueous NH4OH solution at 80 °C. The ZnO films were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The ZnO films exhibited excellent superhydrophilicity (contact angle for water was 0°), while they changed wettability to superhydrophobicity with a water contact angle greater than 150° after further chemical modification with n-dodecanoic acid. The procedure reported here only needs readily available reagents and laboratory equipments, which can be applied to various substrates of any size and shape.  相似文献
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