有机膨润土的制作及其结构研究

有机膨润土是一种新型的乳化剂和分散剂及增稠剂。它由表面活性物质在一定条件下处理蒙脱石研制而成。本文重点研究其制备方法和结构。制成的产品已与美国标准样品同时进行测试,各项指标皆符合要求。     

关于Gerber定理的推广及应用

给出了关于n维单形的Gerber定理的推广,建立了关于单形内点一个更强的几何不等式,并给出了它的一个应用.     

精神家园的深情回望--评王安忆90年代末的短篇小说创作

王安忆90年代末的短篇小说,主要叙写当年知青生活中的亲历往事,深情礼赞淮河儿女的人性美,藉此建构自己的精神家园.这种在岁月回望中寻找、建构精神家园的执着与努力,体现出对当下平庸现实的背离.在文学创作中这并非个例."距离的审美"是王安忆精神家园得以重建的根本原因.     

"切削深度"的定义应予修正

对现行金属切削教材、设计手册及有关文献的"切削深度"定义进行了研究,论述该定义应用场合的局限性及不可操作(确定)性,分析并提出了能适用于各种切削加工情况的且易于操作(确定)的"切削深度"的定义的修正意见.     

审美的距离悠远的韵味--解读卞之琳的《断章》

<断章>是卞之琳的代表作,半个多世纪以来,无数评论家从不同角度对其进行阐释.本文通过"审美距离"对诗歌的形式层、表现层和再现层进行解析.正是由于营造了时空距离、想象距离和情感距离,该诗才显示出无穷的韵味和悠远的理趣.这些距离,既增添了诗歌的审美情韵,又造成了主旨的朦胧性.     

An Additive Genetic Gamma Frailty Model for Linkage Analysis of Diseases with Variable Age of Onset Using Nuclear Families

Many late-onset complex diseases exhibit variable age of onset. Efficiently incorporating age of onset information into linkage analysis can potentially increase the power of dissecting complex diseases. In this paper, we treat age of onset as a genetic trait with censored observations. We use multiple markers to infer the inheritance vector at the disease susceptibility (DS) locus in order to extract information about the inheritance pattern of the disease allele in a pedigree. Given the inheritance distribution at the DS locus, we define the genetic frailty for each individual within a nuclear family as the sum of frailties due to a putative major disease gene and a polygenic effect due to any remaining DS loci. Conditioning on these frailties we use the proportional hazards model for the risk of developing disease. We show that a test of linkage can be formulated as a test of zero variance due to a specific locus of the additive gamma frailties. Maximum likelihood estimation, using the EM algorithm, and likelihood ratio tests are employed for parameter estimation and tests of linkage. A simulation study presented indicates that the proposed method is well behaved and can be more powerful than the currently available allele-sharing based linkage methods. A breast cancer data example is used for illustration.     

Characterization of an optimal matrix estimator under convex loss function

Characterization of an optimal vector estimator and an optimal matrix estimator are obtained. In each case appropriate convex loss functions are considered. The results are illustrated through the problems of simultaneous unbiased estimation, simultaneous equivariant estimation and simultaneous unbiased prediction. Further an optimality criterion is proposed for matrix unbiased estimation and it is shown that the matrix unbiased estimation of a matrix parametric function and the minimum variance unbiased estimation of its components are equivalent.     

因特网约车平台双边报价交易机制创新及策略研究

现有网约车平台采用接受或拒绝的定价交易机制，即乘客和司机被动选择接受或拒绝交易平台给出的定价及加价规则。由于缺乏对平台用户个体需求的了解，当前平台产生的价格不能反映不同交易者的内在诉求，如每个乘客的用车目的、紧急程度、经济能力，司机的实际运行成本、期望收益等差异。由于每个交易者的内在诉求对每笔交易的合理定价具有很大影响，为优化资源配置，将这类信息纳入网约用车市场价格形成机制变得越来越重要。本文设计了基于网约车平台的双边报价交易机制，该机制允许乘客和司机分别进行报价，网约车平台基于每次交易涉及的乘客及司机的报价自动生成交易价格并实现乘客与司机的交易匹配，该机制满足参与理性约束、预算平衡约束，保障乘客和司机获得该机制作用下的所有交易剩余，文章还对该机制下交易人的报价策略及投机策略进行了理性及仿真分析，证明该机制鼓励交易者说真话，从而优化平台资源配置。     

Social interaction distance and stratification

There have been calls from several sources recently for a renewal of class analysis that would encompass social and cultural, as well as economic elements. This paper explores a tradition in stratification that is founded on this idea: relational or social distance approaches to mapping hierarchy and inequality which theorize stratification as a social space. The idea of 'social space' is not treated as a metaphor of hierarchy nor is the nature of the structure determined a priori. Rather, the space is identified by mapping social interactions. Exploring the nature of social space involves mapping the network of social interaction--patterns of friendship, partnership and cultural similarity--which gives rise to relations of social closeness and distance. Differential association has long been seen as the basis of hierarchy, but the usual approach is first to define a structure composed of a set of groups and then to investigate social interaction between them. Social distance approaches reverse this, using patterns of interaction to determine the nature of the structure. Differential association can be seen as a way of defining proximity within a social space, from the distances between social groups, or between social groups and social objects (such as lifestyle items). The paper demonstrates how the very different starting point of social distance approaches also leads to strikingly different theoretical conclusions about the nature of stratification and inequality.