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102.
103.
为支持高速多址网络中二维图像的传输,Kitayama首次提出码分多址并行图像传输系统的概念.作为码分多址并行图像传输系统的首选光地址码,光正交签名码(OOSPC)是一族具有良好相关性的Hamming重量为k的m×n(0,1)-矩阵.用Θ(m,n,k,λ)表示所有参数为(m,n,k,λ)的OOSPC中码字容量可能的最大值,则称码字容量为Θ(m,n,k,λ)的(m,n,k,λ)-OOSPC是最优的.本文将针对满足下列条件之一的正整数m和n:(1)mn≡8,16(mod 24),gcd(m,n,2)=2,且mn≡16(mod 32)和gcd(m,n,4)=2不同时成立,其中m和n的所有奇素因子均模6余1;(2)mn≡0(mod 24)且gcd(m,n,6)=2,证明Θ(m,n,4,1)=|mn-1/12|,即构造码字容量为|mn-1/12|的最优(m,n,4,1)-OOSPC. 相似文献
104.
Fabrice Gritti Irene Leonardis David Shock Paul Stevenson Andrew Shalliker Georges Guiochon 《Journal of chromatography. A》2010,1217(10):1589-1603
The performance of the new Kinetex-C18 column was investigated. Packed with a new brand of porous shell particles, this column has an outstanding efficiency. Once corrected for the contribution of the instrument extra column volume, the minimum values of the reduced plate heights for a number of low molecular weight compounds (e.g., anthracene and naphtho[2,3-a]pyrene) were between 1.0 and 1.3, breaking the legendary record set 3 years ago by Halo-C18 packed columns. The liquid-solid mass transfer of proteins (e.g., insulin and lyzozyme) is exceptionally fast on Kinetex-C18 much faster than on the Halo-C18 column. The different contributions of dispersion and mass transfer resistances to the column efficiency were determined and discussed. The possible reasons for this extremely high column efficiency are discussed. 相似文献
105.
Tommy Clausen Allan Nordlunde Hjorth Morten Nielsen David Pisinger 《European Journal of Operational Research》2010
In this paper we address the problem of assigning seats in a train for a group of people traveling together. We consider two variants of the problem. One is a special case of two-dimensional knapsack where we consider the train as having fixed size and the objective is to maximize the utilization of the seats in the train. The second is a special case of two-dimensional bin packing where all requests must be accommodated while trying to minimize the number of passenger cars needed. For both variants of the problem we present a number of bounds and develop exact algorithms. Computational results are presented for various instances based on realistic data, and from the packing literature adapted to the problems addressed. 相似文献
106.
《化学:亚洲杂志》2017,12(23):2985-2990
Color tuning of organic solid‐state luminescent materials remains difficult and time‐consuming through conventional chemical synthesis. Herein, we reported highly efficient polymorph‐dependent green (P1), yellow (P2), and red (P3) emissions of organic crystals made by the same molecular building blocks of 4‐(2‐{4‐[2‐(4‐diphenylamino‐phenyl)‐vinyl]‐phenyl}‐vinyl)‐benzonitrile (DOPVB). Single‐crystal X‐ray diffraction (XRD) and spectroscopic data reveal that all three polymorphs follow the herringbone packing motif in H‐type aggregations. On the one hand, from P1, P2 to P3, the reduced pitch translation along π stacks increases the intermolecular interactions between adjacent molecules, therefore leading to gradually red‐shifted emissions from 540, 570 to 614 nm. On the other hand, the edge‐to‐face arrangement and large roll translations avoid strong π–π overlap, making P1, P2 and P3 highly emissive with record‐high solid‐state fluorescence quantum yields of 0.60, 0.98, and 0.68, respectively. Furthermore, the optically allowed 0–1 transitions of herringbone H‐aggregates of P1, P2 and P3 naturally provide a four‐level scheme, enabling green and yellow amplified spontaneous emissions (ASE) with very low thresholds. 相似文献
107.
Ian P. Gent 《Journal of Heuristics》1999,5(1):109-111
If special-purpose methods can be overfitted to benchmarks, so can general methods. 相似文献
108.
设X,Y为拓扑空间,f:X→Y,g:y→X.该文证明了下列结论:对每一自然数n, (1)f(Fix((g o,f)n))=Fix((f o g)n),g(Fix((f og )n))=Fix(g o f)n),且#Fix((g o f)n)= #Fix((f o g)n);(2)R((g o f)n)=R((f o g)n). 相似文献
109.
In this paper a comparison is made between two decomposition techniques to solve a staff scheduling problem with column generation.
In the first approach, decomposition takes place on the staff members, whereas in the second approach decomposition takes
place on the activities that have to be performed by the staff members. The resulting master LP is respectively a set partitioning
problem and a capacitated multi-commodity flow problem. Both approaches have been implemented in a branch-and-price algorithm.
We show a trade-off between modeling power and computation times of both techniques. 相似文献
110.
In this paper, locating some warehouses as distribution centers (DCs) in a real-world military logistics system will be investigated. There are two objectives: finding the least number of DCs and locating them in the best possible locations. The first objective implies the minimum cost of locating the facilities and the latter expresses the quality of the DCs locations, which is evaluated by studying the value of appropriate attributes affecting the quality of a location. Quality of a location depends on a number of attributes; so the value of each location is determined by using Multi Attribute Decision Making models, by considering the feasible alternatives, the related attributes and their weights according to decision maker’s (DM) point of view. Then, regarding the obtained values and the minimum number of DCs, the two objective functions are formed. Constraints imposed on these two objectives cover all centers, which must be supported by the DCs. Using Multiple Objective Decision Making techniques, the locations of DCs are determined. In the final phase, we use a simple set partitioning model to assign each supported center to only one of the located DCs. 相似文献