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121.
一种基于瞳面相位差的波前传感器相位恢复   总被引:3,自引:1,他引:2  
杨慧珍  龚成龙 《光学学报》2011,(11):124-129
根据瞳面相位差波前传感器的特点,提出把模式分解和随机并行梯度下降算法结合起来实现波前相位的恢复.以32单元变形镜的初始面形和Roddier提出的相位生成方法随机产生的一帧相屏为研究对象,分析所提出的相位恢复算法的性能.结果表明,两种情况下的畸变波前都得到了很好的恢复.当像差仅含有低阶成分时,使用模式分解法就可获得令人满...  相似文献   
122.
Genetic algorithms are known to be efficient for global optimizing. However, they are not well suited to perform finely-tuned local searches and are prone to converge prematurely before the best solution has been found. This paper uses genetic diversity measurements to prevent premature convergence and a hybridizing genetic algorithm with simplex downhill method to speed up convergence. Three case studies show the procedure to be efficient, tough, and robust.  相似文献   
123.
研究了带反馈链路的选择式频率分集的短波信道FH/MFSK编码系统,在具有加性白高斯噪声(AWGN)的瑞利衰落信道中,存在部分频带噪声阻塞时的性能,给出了采用RS码、双-k码、重发码时,无编码和有编码系统的码符差错率与比特能量噪声比的关系曲线.  相似文献   
124.
This paper applies the two-party dependence theory (Castelfranchi, Cesta and Miceli, 1992, in Y. Demazeau and E. Werner (Eds.) Decentralized AI-3, Elsevier, North Holland) to modelling multiagent and group dependence. These have theoretical potentialities for the study of emerging groups and collective structures, and more generally for understanding social and organisational complexity, and practical utility for both social-organisational and agent systems purposes. In the paper, the dependence theory is extended to describe multiagent links, with a special reference to group and collective phenomena, and is proposed as a framework for the study of emerging social structures, such as groups and collectives. In order to do so, we propose to extend the notion of dependence networks (applied to a single agent) to dependence graphs (applied to an agency). In its present version, the dependence theory is argued to provide (a) a theoretical instrument for the study of social complexity, and (b) a computational system for managing the negotiation process in competitive contexts and for monitoring complexity in organisational and other cooperative contexts.  相似文献   
125.
Asymptotic representations of the difference of M-estimators of the parameters of nonlinear regression model for the full data and for the subsample of data are given for the following three situation: i) fix number of points excluded from data, ii) increasing number, however asymptotically negligible part of data excluded, and finally iii) asymptotically fix portion of data excluded. Asymptotic normality of the difference of estimators (for the two latter cases) is proved.  相似文献   
126.
A novel strategy for avian species identification by cytochrome b gene   总被引:1,自引:0,他引:1  
We report a DNA-based test that can be applied to any avian species so that the amplicon can be used in species identification. The need for the test arose from the requirement to enforce the Wildlife Conservation Act in Taiwan where over 150 avian species are protected. It is difficult to enforce the law if no gross morphology is present and hence there is a requirement to develop a DNA test. This study uses a novel strategy for avian species identification by the cytochrome b gene where a series of primer pairs producing amplicons of decreasing size was designed. The test is designed to produce the largest possible amplicon based upon the quality of the DNA in the sample. A total of 331 avian samples were tested representing 40 species. Sequencing of the amplicons revealed limited intraspecies variation and that no DNA sequence was shared by samples from two different avian species. The closest genetic distance among the 40 species was 0.059 which was between Lonchura punctulata and Estrilda melpoda based upon data from the smallest amplicon. A DNA databank including 138 sequence types from 331 samples tested, representing 40 different species, was constructed in this study. A blind test was used to determine the value for this system for forensic applications that successfully identified the species.  相似文献   
127.
Six heterometallic Zn(II) coordination polymers, Zn(H2O)3(FNA) (1), [NH4]2[Zn(H2O)2(FNA)2] (2), [ZnNa2(FNA)2]·3H2O (3), [ZnK2(FNA)2]·H2O (4), [ZnRb2(FNA)2]·2H2O (5) and [ZnMg(FNA)2]·4H2O (6) (H2FNA = 4-nitrobenzene-1,2-dicarboxylic acid), were synthesised by introducing different alkali/alkaline earth (AeI/AeII) metals. These complexes exhibit diverse structures with the different AeI/AeII metals used and distinct ligand coordination modes the ions provide. For 1 and 2, the Zn(II) centres with distorted octahedra are connected by FNA to form 1-D chain structures. The Zn(II) centres in 36 with distorted tetrahedra are linked by FNA to form 2-D anionic grid layers. For 35, these 2-D anionic grid layers are connected by alkali metal (Na, K and Rb) with the O–AeI–O connectivity to exhibit 3-D framework structures, while 6 features a 2-D Zn–Mg network. Luminescence properties of 16 have been investigated.  相似文献   
128.
X‐chromosomal short tandem repeats (X‐STRs) have been proved to be useful for some deficiency paternity cases in recent years. Here, we studied the genetic polymorphisms of 19 X‐STR loci (DXS10148‐DXS10135‐DXS8378, DXS10159‐DXS10162‐DXS10164, DXS7132‐DXS10079‐DXS10074‐DXS10075, DXS6809‐DXS6789, DXS7424‐DXS101, DXS10103‐HPRTB‐DXS10101 and DXS7423‐DXS10134) in 252 male and 222 female individuals from Guanzhong Han population, China. No deviation for all 19 loci was observed from the Hardy–Weinberg equilibrium. The polymorphism information content values of the panel of 19 loci were more than 0.5 with the exception of the locus DXS7423. The combined power of discrimination were 0.9999999999999999999994340 in females and 0.9999999999997662 in males, respectively; and the combined mean exclusion chances were 0.999999993764 in duos and 0.999999999997444 in trios, respectively. The haplotype diversities for all the seven clusters of linked loci were more than 0.9. The results showed that the panel of 19 X‐STR loci were powerful for forensic applications in Guanzhong Han population. Locus by locus population comparisons showed significant differences at more than seven loci between Guanzhong Han population and the groups from North America, Europe and Africa.  相似文献   
129.
The pollution of arable lands and water with petroleum-derived products is still a valid problem, mainly due the extensive works aimed to improve their production technology to reduce fuel consumption and protect engines. An example of the upgraded fuels is the BP 98 unleaded petrol with Active technology. A pot experiment was carried out in which Eutric Cambisol soil was polluted with petrol to determine its effect on the microbiological and biochemical properties of this soil. Analyses were carried out to determine soil microbiome composition—with the incubation and metagenomic methods, the activity of seven enzymes, and cocksfoot effect on hydrocarbon degradation. The following indices were determined: colony development index (CD); ecophysiological diversity index (EP); index of cocksfoot effect on soil microorganisms and enzymes (IFG); index of petrol effect on soil microorganisms and enzymes (IFP); index of the resistance of microorganisms, enzymes, and cocksfoot to soil pollution with petrol (RS); Shannon–Weaver’s index of bacterial taxa diversity (H); and Shannon–Weaver’s index of hydrocarbon degradation (IDH). The soil pollution with petrol was found to increase population numbers of bacteria and fungi, and Protebacteria phylum abundance as well as to decrease the abundance of Actinobacteria and Acidobacteria phyla. The cultivation of cocksfoot on the petrol-polluted soil had an especially beneficial effect mainly on the bacteria belonging to the Ramlibacter, Pseudoxanthomonas, Mycoplana, and Sphingobium genera. The least susceptible to the soil pollution with petrol and cocksfoot cultivation were the bacteria of the following genera: Kaistobacter, Rhodoplanes, Bacillus, Streptomyces, Paenibacillus, Phenylobacterium, and Terracoccus. Cocksfoot proved effective in the phytoremediation of petrol-polluted soil, as it accelerated hydrocarbon degradation and increased the genetic diversity of bacteria. It additionally enhanced the activities of soil enzymes.  相似文献   
130.
As the population ages globally, there seem to be more people with Alzheimer’s disease. Unfortunately, there is currently no specific treatment for the disease. At present, Huperzine A (HupA) is one of the best drugs used for the treatment of Alzheimer’s disease and has been used in clinical trials for several years in China. HupA was first separated from Huperzia serrata, a traditional medicinal herb that is used to cure fever, contusions, strains, hematuria, schizophrenia, and snakebite for several hundreds of years in China, and has been confirmed to have acetylcholinesterase inhibitory activity. With the very slow growth of H. serrata, resources are becoming too scarce to meet the need for clinical treatment. Some endophytic fungal strains that produce HupA were isolated from H. serrate in previous studies. In this article, the diversity of the endophytic fungal community within H. serrata was observed and the relevance to the production of HupA by the host plant was further analyzed. A total of 1167 strains were obtained from the leaves of H. serrata followed by the stems (1045) and roots (824). The richness as well as diversity of endophytic fungi within the leaf and stem were higher than in the root. The endophytic fungal community was similar within stems as well as in leaves at all taxonomic levels. The 11 genera (Derxomyces, Lophiostoma, Cyphellophora, Devriesia, Serendipita, Kurtzmanomyces, Mycosphaerella, Conoideocrella, Brevicellicium, Piskurozyma, and Trichomerium) were positively correlated with HupA content. The correlation index of Derxomyces with HupA contents displayed the highest value (CI = 0.92), whereas Trichomerium showed the lowest value (CI = 0.02). Through electrospray ionization mass spectrometry (ESI-MS), it was confirmed that the HS7-1 strain could produce HupA and the total alkaloid concentration was 3.7 ug/g. This study will enable us to screen and isolate the strain that can produce HupA and to figure out the correlation between endophytic fungal diversity with HupA content in different plant organs. This can provide new insights into the screening of strains that can produce HupA more effectively.  相似文献   
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