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71.
Jenni J. Seppälä Antti Larjo Tommi Aho Olli Yli-Harja Matti T. Karp Ville Santala 《International Journal of Hydrogen Energy》2013
Genome-scale model was applied to analyze the anaerobic metabolism of Escherichia coli. Three different methods were used to find deletions affecting fermentative hydrogen production: flux balance analysis (FBA), algorithm for blocking competing pathways (ABCP), and manual selection. Based on these methods, 81 E. coli mutants possessing one gene deletion were selected and cultivated in batch experiments. Experimental results of H2 and biomass production were compared against the results of FBA. Several gene deletions enhancing H2 production were found. Correctness of gene essentiality predictions of FBA for the selected genes was 78% and 77% in glucose and galactose media, respectively. 33% of the mutations that were predicted by FBA to increase H2 production had a positive effect in experiments. Batch cultivation is a simple and straightforward experimental way to screen improvements in H2 production. However, the ability of FBA to predict the H2 production rate cannot be evaluated by batch experiments. Metabolic network models provide a method for gaining broader understanding of the complicated metabolic system of a cell and can aid in prospecting suitable gene deletions for enhancing H2 production. 相似文献
72.
Magnetic properties of metal layer deposited by reduction of metal ions contained in polymer with applying magnetic field 总被引:5,自引:0,他引:5
Mitsuhiro Shibata Hiroshi Beniya Ryutoku Yosomiya Takatoshi Yosomiya 《Journal of Polymer Research》2000,7(1):57-61
Metal layer was deposited by the reduction of NiCl2 and CoCl2 in polyacrylonitrile film after applying an external magnetic field in directions parallel and perpendicular to the surface
of the film; the magnetic properties of the metal-deposited film were investigated. When the parallel magnetic field was applied,
the values of coercivity (Hc), remanent flux density (Br) and maximum flux density (Bs) increased regardless of the composition of the metal ions, compared with the case without the application of the magnetic
field. From the scanning electron micrographs and X-ray diffraction analyses, it was shown that the growth of crystalline
orientation in the deposited metals was enhanced by applying a parallel magnetic field. 相似文献
73.
Hyo Kim 《Korean Journal of Chemical Engineering》1999,16(6):764-773
To answer the questions on the behavior of liquid flows under complicatedly combined actions of stresses, evaporation and
temperature-dependent surface tension effects, thin liquid layers flowing under gravity down an inclined plane uniformly heated
from below are considered There may be two thermal boundary conditions on the hot plate, i e , either constant heat flux or
fixed temperature By using long-wave approximation, the nonlinear evolution equations governing the two-dimensional surface
waves have been derived upto O(ε2) and O(ε) for the constant heat flux and the fixed temperature case, respectively Here the small parameter ε(l) is the ratio
of the characteristic length scale parallel to the flow to the initial basic film thickness The linear and the nonlinear stability
analyses are also performed by using numerical calculations Consequently, the flow subjected to the constant heat flux can
be marked as a more stable system than the flow mechanism at a fixed-tem-perature boundary condition. 相似文献
74.
A. H. Li X. L. Wang H. K. Liu M. Ionescu S. X. Dou P. Xuan E. W. Collings 《Journal of Electroceramics》2006,16(4):605-609
YBa2Cu3O7 (Y123) thin films were grown by pulsed laser deposition (PLD) on LaAlO3 (100) substrates whose surfaces were modified by a discontinuously layer of Ag nano-dots. The Y123 films were characterised
by atomic force microscope, X-ray diffraction, scanning electron microscope, and DC magnetization measurements. Effect of
substrate surface modification using various densities of the Ag nano-dots on the improvements of critical current density
J
c
and microstructures in the Y123 films has been studied systematically. The results showed that at fixed physical deposition
conditions J
c
increased with the number of Ag shots, n. Zero field J
c
at 77 K increased from 106 to 3.3 × 106 A/cm2, and from 1.5 × 107up to 4 × 107A/cm2 for 5 K as the number of Ag shots increased from zero to 150. However, a fluctuation of J
c
was observed for n < 60 at 77 and 40 K in both low and high fields. Detailed microstructure analysis revealed that ab misalignment was gradually improved as Ag nano-dots density gradually increased and believed to be responsible for the J
c
enhancement. 相似文献
75.
76.
电厂热经济性计算的分析研究 总被引:5,自引:0,他引:5
文中依据质能守恒原理引入的热平衡结构矩阵计算方法,对电厂热力系统的经济性作计算分析,分析了几种不同影响因素对机组供电煤耗的影响,指出工质参数基准的确定。通过对与循环函数的比较,以及不同容量机组经济性计算结果的数据分析,得出具有实际意义的发电厂机组几个小指标耗差分析计算表。 相似文献
77.
78.
The state of Nevada has extensive mineral resources, and is the largest producer of gold in the USA as well as fourth in world gold production. Mercury (Hg) is often present in the hydrothermal systems that produce gold deposits, and can be found in elevated concentrations in gold ore. As a result, mining of gold ore in Nevada has been shown to release Hg to the atmosphere from point and non-point sources. This project focused on measurement of air-soil Hg exchange associated with undisturbed soils and bedrock outcrops in the vicinity of two large gold mines. Field and laboratory data collected were used to identify the important variables controlling Hg flux from these surfaces, and to estimate a net flux from the areas adjacent to the active mines as well as that occurring from the mined area pre-disturbance. Mean daily flux by substrate type ranged from 9 ng m− 2 day− 1 to 140 ng m− 2 day− 1. Periods of net deposition of elemental Hg were observed when air masses originating from a mine site moved over sampling locations. Based on these observations and measured soil Hg concentrations we suggest that emissions from point and non-point sources at the mines are a source of Hg to the surrounding substrates with the amount deposited not being of an environmental concern but of interest mainly with respect to the cycling of atmospheric elemental Hg. Observations indicate that while some component of the deposited Hg is sequestered in the soil, this Hg is gradually released back to the atmosphere over time. Estimated pre-disturbance emissions from the current mine footprints based on field data were 0.1 and 1.7 kg yr− 1, compared to that estimated for the current non-point mining sources of 19 and 109 kg yr− 1, respectively. 相似文献
79.
清洗对于电子产品可靠性有着非常重要的影响,针对印制电路组件污染物进行了系统阐述,并对不同的清洗技术和工艺进行了总结归纳,讨论了影响清洗效果的各个因素及其检验规范,为实际生产起到了指导性作用。 相似文献
80.
二维过渡金属二硫化物(TMD)晶体由于其结构的多样性和独特的性质备受关注。真空固态反应法是生长高质量二维TMD晶体的一种强有力工具,此方法大大推动了基于二维TMD晶体的基础研究和应用探索。在这篇综述中,我们总结了在真空系统中生长高质量二维TMD晶体的方法,并讨论了影响二维TMD晶体尺寸、质量、形态和多型性的因素。我们还简要讨论了二维TMD晶体的物理性质及各种应用。最后,对真空固态反应法在二维TMD晶体生长中的应用进行了展望。 相似文献