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941.
Kurt Leichtweiß 《manuscripta mathematica》1986,56(4):429-464
Ohne ZusammenfassungHerrn Martin Barner zum 65. Geburtstag gewidmet 相似文献
942.
This paper reviews tools which have great potential for reducing the difficulty of solving IP (and also MIP) problems, if
well implemented in solvers. Recent experiments with Branch and Bound solvers, in connection with “Short Start Features”,
have shown that implementations need and can still be improved. Concepts which are likely to be specially important for (0,1)
MIP are pointed out. 相似文献
943.
We consider the simultaneous linear minimax estimation problem in linear models with ellipsoidal constraints imposed on an unknown parameter. Using convex analysis, we derive necessary and sufficient optimality conditions for a matrix to define the linear minimax estimator. For certain regions of the set of characteristics of linear models and constraints, we exploit these optimality conditions and get explicit formulae for linear minimax estimators. 相似文献
944.
945.
946.
This article reports a comparative study on texturing in silicon and germanium surfaces after exposure to femtosecond laser irradiation in the gaseous environments of sulfur hexafluoride (SF6) and hydrogen chloride (HCl). The surface texturing results from the combined effect of laser-assisted chemical etching and laser ablation. Optimized processing conditions have produced features on the order of nanometers in size. We demonstrate for the first time that regular conical pillars can be formed in Ge and that HCl can be used to form regular conical pillars in Si. 相似文献
947.
A highly convergent, scalable synthesis of the rebeccamycin analog 2 was demonstrated in seven steps and 31% overall yield based on the N-protected building block dibromomaleimide 7. The practical synthesis of other two building blocks, 5,6-difluoro-3-benzothiopheneboronic acid 6 and 5,6-difluoroindole 8, is described. 相似文献
948.
Norling L Lute S Emery R Khuu W Voisard M Xu Y Chen Q Blank G Brorson K 《Journal of chromatography. A》2005,1069(1):79-89
We evaluated viral clearance in multiply-cycled anion-exchange media run in flow-through mode. We found that anion-exchange columns do not lose viral clearance capacity after extensive re-use, if they are cleaned with recommended buffers that do not chemically degrade the media. In contrast, anion-exchange (AEX) columns that are not cleaned or are cleaned with buffers that chemically degrade the media lost viral clearance capacity after extended use. In these cases, other performance attributes that changed at the same time were increased band spreading, decreased DNA clearance and accumulating backpressure that prevented re-use past 80-120 cycles. Thus, our data suggests that flow through mode anion-exchange columns that are cleaned with recommended cleaning buffers, and periodically monitored for band spreading, DNA clearance and/or backpressure need not be re-evaluated for viral clearance at the end of the validated media lifetime. 相似文献
949.
DNA-programmed organic reactions are new and powerful tools for assembling chemical compounds into predetermined complex structures and a brief review of their use is given. This approach is particular efficient for the selection and covalent coupling of multiple components. DNA-templated synthesis is used for polymerization of PNA tetramers and for copying of the connectivity information in DNA. Direct DNA-programmed multicomponent coupling of custom designed organic modules is described. The macromolecular structures obtained are highly conjugated potentially conducting nanoscaffolds. Some future developments in this area are discussed. 相似文献
950.