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排序方式: 共有4483条查询结果,搜索用时 194 毫秒
981.
982.
稀土在激光熔覆涂层中的分布和行为 总被引:23,自引:2,他引:23
用激光快速熔凝法研究了加入钢表层稀土的行为和分布。结果表明,因用激光处理含稀土的涂层能够使较多的稀土偏聚到钢的表层;偏聚到钢表层的过饱和稀土除与氧、硫作用外,还可固溶于晶内、晶界或晶界附近,甚至能形成金属间化合物RE2Fe17;经过激光处理后表面稀土的作用更为明显 相似文献
983.
《Electrophoresis》2018,39(17):2246-2252
Upconversion nanoparticles (UCNPs) are an emerging class of optical materials with high potential in bioimaging due to practically no background signal and high penetration depth. Their excellent optical properties and easy surface functionalization make them perfect for conjugation with targeting ligands. In this work, capillary electrophoretic (CE) method with laser‐induced fluorescence detection was used to investigate the behavior of carboxyl‐silica‐coated UCNPs. Folic acid, targeting folate receptor overexpressed by wide variety of cancer cells, was used for illustrative purposes and assessed by CE under optimized conditions. Peptide‐mediated bioconjugation of antibodies to UCNPs was also investigated. Despite the numerous advantages of CE, this is the first time that CE was employed for characterization of UCNPs and their bioconjugates. The separation conditions were optimized including the background electrolyte concentration and pH. The optimized electrolyte was 20 mM borate buffer with pH 8. 相似文献
984.
A laser processed micro-supercapacitor (LPMS) based on carbon nanotubes/manganese dioxide composite is fabricated through slurry dispensing and laser scribing techniques. This device presents superior electrochemical performance and aesthetic property. 相似文献
985.
A simple method utilizing laser writing technology to fabricate all-solid-state micro-supercapacitors was reported. The solid-state micro-supercapacitors based on MnO2/graphene nanocomposites deliver high volumetric capacitances, promising energy density, good stability and low leakage current. 相似文献
986.
Gadolinium oxide - Graphene (Gd2O3-G) nanocomposites were prepared with different weight ratio of graphene using low temperature solution process. The structural, morphological, electrochemical and photocatalytic properties of the composites were investigated by X-ray diffraction, Raman, FE-SEM, HRTEM, Cyclic voltammetric and photo-degradation analysis. The chemical composition of the composites was studied by elemental mapping analysis using EPMA. The binding states of various elements present in the composites were analyzed by XPS. Cyclic voltammetric studies revealed that the nanocomposite with 5% graphene exhibits the specific capacitance of 26 F g−1, which is higher than that of pure Gd2O3 (18 F g−1). The presence of graphene has greatly enhanced the photocatalytic performance of Gd2O3G composites as the rate of degradation of MB dye is relatively higher in the composites compared to pure Gd2O3. The significant increase in the specific capacitance and rate of degradation of dye suggest that the Gd2O3G is a promising material for energy storage and environmental applications. 相似文献
987.
We report a novel separation method that is applicable to both DNA and protein samples, based on electrophoresis in a three-dimensional (3-D) geometry. In contrast to conventional electrophoresis, samples are applied in a two-dimensional, planar array to one of the surfaces of a 3-D geometry separation medium. Loading onto a plane results in a very high sample capacity. Sample migration and separation occur along the third spatial dimension, which is perpendicular to the loading plane. The key problem of electrophoresis in a 3-D geometry separation setup is that temperature gradients are caused by Joule's heat, affecting the electrical conductivity and viscosity of the separation medium. A means of achieving straight sample migration under these circumstances is to force heat flow through the separation medium parallel to the axis of sample migration. This can be done by dissipating the heat via the electrode sides of the gel and blocking any other heat transfer. The separation of DNA and proteins by this method has been tested using agarose gel electrophoresis, polyacrylamide gel electrophoresis, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Data were acquired off-line by conventional staining methods as well as on-line by detection of laser-induced fluorescence. We describe how to excise samples from the separation medium for preparative purposes. Possible unique applications of this 3-D geometry electrophoresis separation method are also discussed. 相似文献
988.
Pulsed IR laser ablation of poly(ethylene succinate) results in the formation of volatile products (mainly carbon oxides, hydrogen, C1-C4 hydrocarbons) and affords deposition of polymeric films. Composition, structure and molecular weight distribution of the latter products were examined by EDX-SEM, FTIR, UV and NMR spectroscopy and gel permeation chromatography and revealed to be virtually identical to the initial poly(ethylene succinate). The deposited films and poly(ethylene succinate) decompose in the same way, as proved by TGA analysis. The formation of the volatile products is accounted for by random cleavages of the polymer backbone. The deposition of the polymeric products is judged to be due to molecular ester group interchange and/or a sequence of the C-C bond homolysis and recombination of the produced radicals. 相似文献
989.
990.
Element determination in solid waste products from the steel industry usually involves the time-consuming step of preparing a solution of the solid. Laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS) has been applied to the analysis of Cr, Ni, Cu, As, Cd and Sn, elements of importance from the point of view of their impact on the environment, in electric arc furnace flue dust (EAFD). A simple method of sample preparation as pressed pellets using a mixture of cellulose and paraffin as binder material was applied. Calibration standards were prepared spiking multielement solution standards to a 1:1 ZnO + Fe2O3 synthetic matrix. The wet powder was dried and mechanically homogenised. Quantitative analysis were based on external calibration using a set of matrix matched calibration standards with Rh as a internal standard. Results obtained using only one-point for calibration without matrix matched, needing less time for standardization and data processing, are also presented. Data are calculated for flue dust reference materials: CRM 876-1 (EAFD), AG-6203 (EAFD), AG-6201 (cupola dust) and AG-SX3705 (coke ashes), and for two representative electrical arc furnace flue dusts samples from Spanish steelmaking companies: MS-1 and MS-2. For the reference materials, an acceptable agreement with certificate values was achieved, and the results for the MS samples matched with those obtained from conventional nebulization solutions (CN). The analytical precision was found to be better than 7% R.S.D. both within a single pellet and between several pellets of the same sample for all the elements. 相似文献