二次矩阵方程最大最小解存在的充分条件

给出二次矩阵方程Q(X)=AX^2 BX C=0的最大解和最小解存在的充分条件,并且讨论了二次λ-矩阵多项式Q(λ)=λ^2A λB C特征值的性质．     

考虑网络平台服务、消费者需求差异的混合供应链决策

文章研究了由制造商、零售商和网络平台构成的混合供应链系统,构建了混合供应链4种不同的模式:M-M-HSC模式,N-M-HSC模式,M-R-HSC模式和N-R-HSC模式,给出各个模式相应的定价、佣金以及利润等决策,分析消费者需求差异对各个模式运行的影响.研究表明:1)网络平台收取的佣金主要受制造商主导地位的影响,在M-R-HSC模式中,佣金以及网络平台的利润随着消费者网购偏好的增加而增加;在其他模式中,佣金以及网络平台的利润随着消费者网购偏好的增加呈现先增后减的趋势.2)产品的批发价格主要受制造商在传统渠道中的主导权影响,产品的网上销售价格主要受制造商在E-供应链中的主导权力影响.而且无论是产品的批发价格,网上销售价格还是制造商的利润,混合供应链的利润都随着消费者网络偏好的增加而增加.3)在4种模式中,零售商的利润及零售价格的大小是一一对应的,价格和利润都在M-R-HSC模式中最高,在N-M-HSC模式中最低.而且零售价格和零售商的利润随着消费者网购偏好系数的增加而减少.4)制造商主导混合供应链的运作模式有利于系统的运行.这些研究结论会进一步丰富发展混合供应链的理论基础,有利于供应链企业的运营发展.     

CLASSICAL TIME DEPENDENT SOLUTION FORNEUTRON TRANSPORT IN A SLAB WITHGENERALIZED BOUNDARY CONDITIONS

1.IntroductionSincethepioneeringworkofLehner,WingandJorgens['3],thetimedependentneutrontransportproblemhasbeentreatedbymanyinvestigators,andtheliteratureonthissubjectisconsiderable.Variousmethods,theCO-semigroupmethodin[2,3],theNeumannseriesexpansionmetho…     

非奇异H矩阵的判据

本文给出了非奇异Ｈ 矩阵若干新的判据,进一步研究了文［１］ 的相应结果     

对角占优矩阵研究

研究了对角占优矩阵的性质,给出了此类矩阵奇异的一个充分条件和一个充分必要条件,同时给出了它的LU分解形式.     

Change of bacterial community in the Malan Ice Core and its relation to climate and environment

In order to understand the relationship between the community structure of bacteria in ice core and the past climate and environment, we initiated the study on the microorganisms in the three selected ice samples from the Malan ice core drilled from the Tibetan Plateau. The 16S ribosomal DNA (rDNA) molecules were directly amplified from the melt water samples, and three 16S rDNA clone libraries were established. Among 94 positive clones, eleven clones with unique restriction pattern were used for partial sequence and compared with eight reported sequences from the same ice core. The phylotypes were divided into 5 groups: alpha, beta, gamma proteobacteria; CFB, and other eubacteria group. Among them, there were many “typical Malan glacial bacteria“ pertaining to psychrophilies and new bacteria found in the ice core. At a longer time scale, the concentration distribution of “typical Malan glacial bacteria“ with depth showed negative correlation with temperature variations and was coincident with dirty layer. It implied the influence of temperature on the microbial record through impact on the concentrations of the “typical Malan glacial bacteria“. In addition, the nutrition contained in ice was another important factor controlling the distribution of microbial population in ice core section. Moreover, the result displayed an apparent layer distribution of bacterial community in the ice core section, which reflected the microbial response to the past climatic and environmental conditions at the time of deposition.     

用乳酸菌降解猪血培养基中的亚硝酸盐

为了减少食品中对人体有害的硝酸盐含量．进行了不同乳酸菌降解猪血培养基中硝酸盐的实验。结果表明：亚硝酸盐降解量与培养液的pH值呈负相关，pH值下降速度越快，亚硝酸盐的降解速度也越快。乳酸杆菌产酸能力强于球菌，使环境pH值快速下降。导致发酵后期乳酸杆菌对亚硝酸盐的降解能力大于球菌。发酵液酸度越大，pH值越小，亚硝酸盐降解作用越显著。     

微生物青贮剂在玉米秸秆黄贮中的作用

玉米秸秆黄贮过程中接种乳酸菌可以迅速降低原料的pH值，有效抑制腐败菌生长；添加纤维素酶，可以使秸秆的纤维含量由原来的35．3％降低到25．3％，并增加可溶性碳水化合物含量；同时使用酵母菌，可使粗蛋白含量提高10％．所以，微生物青贮剂的使用，能有效改善黄贮秸秆的品质和营养价值．     

邻接对角占优矩阵及其特征值分布

引入邻接对角占优矩阵的概念，给出了邻接对角占优矩阵为广义严格对角占优矩阵的一些充要条件．利用这些结果，得到了新的矩阵特征值的分布区域，改进了Brauer关于矩阵的谱包含域的结果。并推广了现有的一些相应结果．