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131.
I. J. Ferrer C. De Las Heras N. Menéndez J. Tornero C. Sánchez 《Journal of Materials Science》1993,28(2):389-393
Mössbauer spectroscopy has been used to analyse FeS2 thin films obtained by sulphidation of 57Fe evaporated layers. Complementary characterization of the films has been carried out by X-ray diffraction and optical absorption measurements. It is concluded that the two processes (formation and crystallization of FeS2) which lead to polycrystalline FeS2 films are strongly influenced by the temperature at which sulphidation is accomplished. The composition of the films drastically changes at temperatures which depend on the thickness of the Fe film to be sulphidated, and their crystallization seems to show a critical temperature at which the crystallization process is severely altered. Optical properties of the pyrite films seem to depend strongly on their stoichiometry. 相似文献
132.
标准气体微流量计的性能测试 总被引:1,自引:1,他引:0
主要介绍标准微流量计的性能测试。测试结果表明;气体流量的测量范围为17.1×10-5~1.22×10-5pa·L/s,不确定度小于2%。 相似文献
133.
门乃姣 《水利水电工程设计》2006,25(1):10-12,19
龙口水利枢纽工程设计过程中,充分考虑了各方面因素,合理利用地形和地质条件,解决了狭窄河道多建筑物枢纽总体布置、多泥沙河流排沙及大流量泄洪消能设施设计等问题,并经整体水工模型试验验证设计方案合理、切实可行。 相似文献
134.
本文详细分析了现有输入噪声模型和输出噪声模型的抗噪声原理,提出了一种能同时抑制输入噪声和输出噪声的无偏差估计模型,它利用二次互功率谱代替通常估计中的自功率谱。使得由于噪声引起的误差可以通过多次平均完全消除。新估计模型的精度与输入噪声和输出噪声的水平无关,仅与统计次数有关。在输入、输出噪声不相关条件下,即使相干函数很低仍能通过多次平均获得具有足够精度的频响函数值。文章最后给出了不同噪声干扰下的(?)估计值、(?)估计值以及本文模型的(?)估计值,并与没有噪声干扰下的H_o 值进行比较。 相似文献
135.
P Johansen Y Men R Audran G Corradin HP Merkle B Gander 《Canadian Metallurgical Quarterly》1998,15(7):1103-1110
PURPOSE: Tetanus toxoid (Ttxd) encapsulated in polyester microspheres (MS) for single injection immunization have so far given pulsatile in vitro release and strong immune response in animals, but no boosting effect. This has been ascribed to insufficient toxoid stability within the MS exposed to in vivo conditions over a prolonged time period. This study examined the effect of co-encapsulated putative stabilizing additives. METHODS: Two different Ttxd were encapsulated in poly(D,L-lactic-co-glycolic acid) (PLGA 50:50) and poly(D,L-lactic acid) (PLA) MS by spray-drying. The influence of co-encapsulated additives on toxoid stability, loading in and release from the MS, was studied by fluorimetry and ELISA. RESULTS: Co-encapsulated albumin, trehalose and gamma-hydroxypropyl cyclodextrin all improved the toxoid encapsulation efficiency in PLGA 50:50 MS. Albumin increased the encapsulation efficiency of antigenic Ttxd by one to two orders of magnitude. Further, with albumin or a mixture of albumin and trehalose ELISA responsive Ttxd was released over 1-2 months following a pulsatile pattern. CONCLUSIONS: Optimized Ttxd containing MS may be valuable for a single-dose vaccine delivery system. 相似文献
136.
Diñeiro Y Menéndez MI Blanco-López MC Lobo-Castañón MJ Miranda-Ordieres AJ Tuñón-Blanco P 《Analytical chemistry》2005,77(20):6741-6746
A methodology based on density functional theory calculations for the design of molecularly imprinted polymers (MIPs) is described. The method allows the rational choice of the most suitable monomer and polymerization solvent among a set of chemicals traditionally used in MIP formulations for the molecular imprinting of a given template. It is based on the comparison of the stabilization energies of the prepolymerization adducts between the template and different functional monomers. The effect of the polymerization solvent is included using the polarizable continuum model. A voltammetric sensor for homovanillic acid was constructed using different MIPs as recognition element, confirming that the solvent (toluene) and functional monomer (methacrylic acid) selected according to the theoretical predictions lead to the most efficient molecular recognition sensing phase. With the voltammetric sensor prepared using the MIP designed according to the theoretical predictions, a linear response for concentrations of homovanillic acid between 5 x 10(-8) and 1 x 10(-5) M can be obtained. The limit of detection is 7 x 10(-9) M. The selectivity obtained for homovanillic acid over other structurally related compounds buttresses the validity of this strategy of design. 相似文献
137.
138.
An approach to achieve spectral filtering is proposed, using a fibre Bragg grating (FBG) embedded polarisation maintaining fibre Sagnac loop mirror (SLM) through temperature tuning. The opposite temperature sensitivities of the FBG Bragg resonance wavelengths and the interferometric peaks of the fibre SLM, as well as their pronounced difference in bandwidth, provide an opportunity to realise spectral filtering. 相似文献
139.
Microcystis aeruginosa has quickly risen in infamy as one of the most universal and toxic bloom-forming cyanobacteria. Here we presented a species of golden alga (Poterioochromonas sp. strain ZX1), which can feed on toxic M. aeruginosa without any adverse effects from the cyanotoxins. Using flow cytometry, the ingestion and maximal digestion rates were estimated to be 0.2∼1.2 and 0.2 M. aeruginosa cells (ZX1 cell)−1 h−1, respectively. M. aeruginosa in densities below 107 cells mL−1 could be grazed down by ZX1, but no significant decrease was observed when the initial density was 3.2 × 107 cells mL−1. ZX1 grazing was a little influenced by the light intensity (0.5∼2500 lx) and initial pH of the medium (pH = 5.0∼9.5). ZX1 could not survive in continuous darkness for longer than 10 days. The pH value was adjusted to 8 by ZX1 while to 10 by M. aeruginosa. This study may shed light on understanding the ecological interactions between M. aeruginosa and mixotrophic Poterioochromonas sp. in aquatic ecosystems. 相似文献
140.