排序方式: 共有6条查询结果,搜索用时 62 毫秒
1
1.
Hosseinkhani S 《Cellular and molecular life sciences : CMLS》2011,68(7):1167-1182
Firefly luciferase-catalyzed reaction proceeds via the initial formation of an enzyme-bound luciferyl adenylate intermediate.
The chemical origin of the color modulation in firefly bioluminescence has not been understood until recently. The presence
of the same luciferin molecule, in combination with various mutated forms of luciferase, can emit light at slightly different
wavelengths, ranging from red to yellow to green. A historical perspective of development in understanding of color emission
mechanism is presented. To explain the variation in the color of the bioluminescence, different factors have been discussed
and five hypotheses proposed for firefly bioluminescence color. On the basis of recent results, light-color modulation mechanism
of firefly luciferase propose that the light emitter is the excited singlet state of OL− [1(OL−)*], and light emission from 1(OL−)* is modulated by the polarity of the active-site environment at the phenol/phenolate terminal of the benzothiazole fragment
in oxyluciferin. 相似文献
2.
In this paper, the joint production and recycling problem is investigated for a hybrid manufacturing and remanufacturing system
where brand-new products are produced in the manufacturing plant and recycled products are remanufactured into as-new products
in the remanufacturing facility. Both the brand-new products and remanufactured products are used to satisfy customer demands.
Returns of used products that are recycled from customers are assumed to be stochastic and nonlinearly price-dependent. A
mathematical model is proposed to maximize the overall profit of the system through simultaneously optimizing the production
and recycling decisions, subject to two capacity constraints — the manufacturing capacity and the remanufacturing capacity.
Based on Lagrangian relaxation method, subgradient algorithm and heuristic algorithm, a solution approach is developed to
solve the problem. A representative example is presented to illustrate the system, and managerial analysis indicates that
the uncertainties in demand and return have much influence on the production and recycling policy. In addition, twenty randomly
produced examples are solved, and computational results show that the solution approach can obtain very good solutions for
all examples in reasonable time. 相似文献
3.
LI Jian ZHAO ChengGang CAI GuoQing ASREAZAD Saman XU Xi Frank HUANG QiDi 《科学通报(英文版)》2013,58(27):3422-3429
In this paper, based on the porous media theory, the specific expressions of the total stress and the input work of unsaturated expansive soils with double porosity are proposed, and then the energy-conjugate variables are further derived. We make distinctions between the effects of capillary water and adsorbed water on the soil behaviour, as well as between the deformations of microand macrostructure. According to the derived input work expression and the work-energy-dissipation relations for an open multiphase thermodynamic system, we establish a thermodynamics-based modelling framework for unsaturated expansive soils with double porosity. 相似文献
4.
Kinetic modeling of copper bioleaching from low-grade ore from the Shahrbabak Copper Complex 下载免费PDF全文
Saman Beikzadeh Noei Saeed Sheibani Fereshteh Rashchi Seyed Mohammad Javad Mirazimi 《矿物冶金与材料学报》2017,24(6):611-620
The copper recovery from low-grade copper sulfide ore was investigated using microbial leaching. Several parameters substantially affect the bioleaching of copper; among them, pulp density and nutrient media were selected for investigation. The optimum conditions for copper recovery were a pulp density of 5 g/mL, a mixed-mineral salt medium of Acidithiobacillus thiooxidans (70vol%) and Acidithiobacillus ferrooxidans (30vol%), and 10vol% of inoculum. Under these conditions, the maximum bioleaching capacity of the medium for copper recovery was determined to be approximately 99%. The effect of pulp density on the kinetics of the bioleaching process was surveyed using both da Silva's method and constrained multilinear regression analysis. The kinetics of copper dissolution followed the shrinking core model, and the process was diffusion controlled at a pulp density of 5 g/mL. Nevertheless, at higher pulp densities, the process was controlled by chemical reaction. 相似文献
5.
Saman Eskandarzadeh Kourosh Eshghi Mohammad Modarres Yazdi Mohsen Bahramgiri 《系统科学与系统工程学报(英文版)》2014,23(3):312-328
In this paper, we address a basic production planning problem with price dependent demand and stochastic yield of production. We use price and target quantity as decision variables to lower the risk of low yield. The value of risk control becomes more important especially for products with short life cycle. This is because, the profit implications of low yield might be unbearable in the short run. We apply Conditional Value at Risk (CVaR) to model the, risk. CVaR measure is a coherent risk measure and thereby having nice conceptual and mathematical underpinnings. It is also widely used in practice. We consider the problem under general demand function and general distribution function of yield and find sufficient conditions under which the problem has a unique local maximum. We also both analytically and numerically analyze the impact of parameter change on the optimal solution. Among our results, we analytically show that with increasing risk aversion, the optimal price increases. This relation is opposite to that of in Newsvendor problem where the uncertainty lies in demand side. 相似文献
6.
Expression of human fibroblast interferon gene in Escherichia coli 总被引:15,自引:0,他引:15
The human fibroblast interferon gene was inserted in a thermoinducible expression plasmid under control of the phage lambda PL promoter. The primary translation products predicted on the basis of the plasmid constructions were hybrid proteins starting with beta-lactamase or phage MS2 polymerase information followed by the total preinterferon. On induction, antiviral activity, whose physico-chemical, immunological and biological characteristics closely corresponded to those of authentic human fibroblast interferon, was synthesized. Processing to a size compatible with mature but unglycosylated authentic product was observed. 相似文献
1