棒状薄层色谱法在焦化蜡油族组成分析中的应用

建立了快速测定焦化蜡油族组成的薄层色谱／氢火焰（TLC／FID）检测法，使用2种展开剂可以将试样很好地分成饱和烃、芳烃、胶质和沥青质．以经典柱色谱法测得的数据为基准，考察了方法的准确度，2种方法的绝对偏差不大于3％．同时对方法的精密度进行了考察，相对标准偏差小于5％，方法简单快速，每分析10个样品仅需3h，为蜡油族组成分析提供了一个方便快速的方法．     

苯衍生物急性毒性与分子结构的定量相关研究

苯衍生物是一类重要的有机污染物之一,研究苯衍生物的毒性与分子结构之间的关系具有重要意义.用Dragon计算了69个苯衍生物的一系列分子结构参数,通过逐步回归分析,选择了醇/水分配系数(MlogP)、Balaban指数(Jhete)、Barysz矩阵特征值之和(SEigZ)及指示变量(I)等4个结构参数对苯衍生物致呆鲦鱼的急性毒性(-logLC50)建立多元线性回归模型,得到R=0.997 7,s=0.30;交叉验证结果为Rcv=0.909 0,scv=0.33.与文献结果比较,建立的QSAR模型所用参数少,建模方法简单,物理意义明确,且模型性能优于文献报道结果.     

GPS(RTK)技术原理及精度影响因素

简述GPS的应用以及原理,RTK技术的原理、方法、组成结构、精度影响的因素、提高精度的注意事项等等.     

试论HDPE检查井漏水处理方法

在市政污水处理工程中,传统的污水检查井是采用砖砌或混凝土井制成,这种井在结构上虽然结实可靠,但是工期较长,成本较大。目前,在国外已经大量采用HDPE塑料检查井代替传统的砖砌井和混凝土井。特别是在中东地区和德国,HDPE塑料检查井已经得到广泛应用,其配套的检测疏通清洗和维修技术也已经成熟。在不远的将来,这种新型的材料也很可能会大量应用到我国的城市污水工程上。结合我公司在中东地区承建的阿曼马斯喀特污水工程,本文就HDPE污水检查井的修复做些介绍。     

限定性范围副词的再分类及其与N(P)组合分析

通过语言事实的考察,对双音节限定性范围副词的再分类及其与名词或名词短语的组合问题进行分析和探讨,以揭示它们在句法功能上的共性与差异性。     

具有负系数的解析函数的新子类及其性质

利用解析函数邻域的概念,并应用卷积、超几何函数构造了算子L(a,c),讨论了与算子L(a,c)相关的性质,主要证明了(n,δ)邻域以及解析函数新子类的包含关系.     

关于序列商π的（P）映射

建立了度量空间的序列商π的（P）映像的内在特征.     

Optimal policy with a total order quantity commitment contract in the presence of a spot market

In this paper,the optimal policy is considered when the buyer faces two supply sources:one is the contract supplier from which the buyer orders over a specific contract period(say,a year) at a pre-agreed price,and the other is the spot market.However,when ordering from the contract supplier,the buyer must fulfill a pre-determined total order quantity,or the so-called definite total order quantity commitment,over the whole contract period.In other words,the commitment secures the buyer a fixed price but obliges him/her a total order quantity over the contract period.Although the spot market gives the buyer more flexibility in terms of order quantities,its prices are volatile.Such a combination of contract and spot procurements is often observed in practice.Within the contract period,there are multiple sub-periods,during each of which the buyer reviews the inventory,issues an individual order,and uses the on-hand inventory to meet the random demand.Thus,in each(ordering) period,the buyer will weigh between the current known spot price(by procuring from the spot market) and a lower future price(by waiting while consuming the remaining commitment).An optimal dual ordering policy is characterized for each period,depending on the on-hand inventory level,the spot price,and the remaining commitment quantity.The optimal policy in each period is also shown to be independent of the contract price.Through a numerical study,the inventory cost is demonstrated to be(1) insensitive to the contract price when the total commitment quantity is lower than the total expected demand over the contract period and(2) non-increasing in the variability of spot prices.     

过热蒸汽袋式除尘器CFD分析

过热蒸汽袋式除尘器是以过热蒸汽为动力的过热蒸汽气流磨的重要组成部分。利用计算流体动力学（CFD）软件的FLUENT工具模拟及评价了按照传统方法设计的过热蒸汽袋式除尘器，通过对滤袋间隙气流、温度场、压力场的分析显示，按照传统的设计方法模拟设计的过热蒸汽袋式除尘器流场分布均匀，能满足设备运行要求，相关参数可为设备改进及工业放大提供依据。     

Capacitated stochastic coloured Petri net-based approach for computing two-terminal reliability of multi-state network

Classical network reliability problems assume both networks and components have only binary states,fully working or fully failed states.But many actual networks are multi-state,such as communication networks and transportation networks.The nodes and arcs in the networks may be in intermediate states which are not fully working either fully failed.A simulation approach for computing the two-terminal reliability of a multi-state network is described.Two-terminal reliability is defined as the probability that d units of demand can be supplied from the source to sink nodes under the time threshold T.The capacities of arcs may be in a stochastic state following any discrete or continuous distribution.The transmission time of each arc is also not a fixed number but stochastic according to its current capacity and demand.To solve this problem,a capacitated stochastic coloured Petri net is proposed for modelling the system behaviour.Places and transitions respectively stand for the nodes and arcs of a network.Capacitated transition and self-modified token colour with route information are defined to describe the multi-state network.By the simulation,the two-terminal reliability and node importance can be estimated and the optimal route whose reliability is highest can also be given.Finally,two examples of different kinds of multistate networks are given.