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11.
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《Sensors and actuators. B, Chemical》2006,113(1):106-111
A stable film made from hydroxyethylcellulose (HEC) on pyrolytic graphite (PG) electrode was employed for incorporating hemoglobin (Hb), myoglobin (Mb) and horseradish peroxidase (HRP), and the electrochemical characteristics of the proteins were studied correspondingly. Experimental results revealed that HEC film could greatly accelerate electron transfer between the proteins and electrode, and the proteins showed a thin layer electrochemical behavior in the film. Moreover, all the proteins in the film exhibited good catalytic activity towards the reduction of hydrogen peroxide (H2O2) in the low H2O2 concentration range. In the high concentration range, H2O2 would exhibit toxicity effect on the proteins. The electrochemical properties and electrocatalytic abilities of the three heme proteins in HEC film have been compared, and the optimal conditions for H2O2 biosensor fabrication have been obtained. 相似文献
13.
《Computers & Geosciences》2006,32(8):1205-1220
In deepwater-reservoir modeling, the proper representation of the spatial distribution of architectural elements is important to account for pore-volume distribution and the connectivity of reservoir sand bodies. This is especially critical for rock and fluid-volume estimates, reservoir-performance predictions, and development-well planning.A new integrated stochastic reservoir-modeling approach (ModDRE—Modeling Deepwater Reservoir Elements) accounts for geomorphic and stratigraphic controls to generate the deepwater-reservoir architecture. Information on stratal-package evolution and sediment provenance can be integrated into the reservoir-modeling process. A slope-area analytical approach is implemented to account for topographical constraints on channel and sheet-form reservoir architectures and their distribution. Inferred sediment–source statistics and architectural-element variability (from seismic, outcrop, and stratigraphic studies) associated with relative changes in sea level can also be used to constrain the deepwater-reservoir-element statistics. Based on these geomorphic and stratigraphic constraints, deepwater-reservoir elements (channels, lobes) are built into the model sequentially (in stratigraphic order).Integration of realistic geological and engineering attributes into deepwater-reservoir models is vital for optimal reservoir management. This approach is unique in that it is more directly constrained to geomorphic and stratigraphic parameters than traditional object- or surface-based techniques for stochastic deepwater-reservoir modeling. 相似文献
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在弹丸外弹道优化设计中,需对优化设计变量赋于初始值.初始值选取得如何,对整个优化计算所耗机时、迭代点收敛到哪个极值点上等等,影响很大.该文对初始值的选取原则、选取方法等作了讨论,所得结果也可作为对弹丸主要结构参数选优的预估. 相似文献
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《Engineering Analysis with Boundary Elements》2006,30(9):799-807
This paper describes a new method for direct numerical evaluation of multidimensional hypersingular integrals assigned on smooth curves and surfaces. These integrals arise when the boundary integral equations are used to solve problems of mechanics, electrodynamics, aerodynamics, etc. The hypersingular integrals are considered, in the sense of Hadamard, as finite parts. The main advantage of the proposed method is the numerical computation of the hypersingular integrals by the direct application of the developed cubature formulas, thus requiring little analytical pre-work. The method is not restricted to the type of problem however and may be easily applied to any hypersingular integrals. The convergence of the proposed technique has been proved and error estimates are given. An illustrative example demonstrates the accuracy and efficiency of the method. 相似文献
19.
《Diamond and Related Materials》2007,16(3):526-530
Vickers hardness of the cubic BC2N has been investigated using the microscopic hardness model, in which the parameters have been obtained using first principles calculations. Ionicities of the chemical bonds in the cubic BC2N depend on their surrounding chemical environments, which are included in the hardness calculations of the cubic BC2N using the population ionicity scale. For the four selected configurations of the cubic BC2N, the theoretical Vickers hardness has been found to lie between 70 and 72 GPa, consistent with the experimental value of 76 GPa. According to our calculations, it should be the cubic BC2N that ranks second among the superhard materials instead of the cubic BN. 相似文献
20.
This article presents a detailed investigation on the influence of the phosphorus element upon the laser sintering of a multicomponent
Cu-based metal powder system consisting of Cu, Cu-10Sn, and Cu-8.4P. Powder systems containing 0, 10, 15, and 20 wt pct CuP
were sintered in atmosphere at room temperature using the following optimal processing parameters: laser power of 350 W, scan
speed of 0.04 m/s, scan line spacing of 0.15 mm, and layer thickness of 0.25 mm. It was found that the relative density of
the sintered sample with 15 wt pct CuP increased by 24,4 pct as compared with the sample without phosphorus addition. A further
increase in the CuP content (≥20 wt pct), however, resulted in a poor densification with a serious delamination. The exact
metallurgical roles of the phosphorus element in the laser sintering process were addressed as follows. First, the phosphorus
could prevent the sintering system from oxidation by forming CuPO3, thereby improving the wetting characteristics and the sintering kinetics. Second, the phosphorus could decrease the surface
tension of molten materials, leading to a successive transition from highly discontinuous sintered tracks to fairly coherent
ones with increasing the phosphorus content. Third, the phosphorus could lower the melt viscosity, thereby improving the microstructural
homogeneity of the laser-sintered samples. 相似文献