数据挖掘中聚类方法比较研究

聚类是数据挖掘领域中的一个重要研究课题。聚类在电子商务、图像处理、模式识别、本分类等领域有广泛的应用。本首先建立了数据挖掘中聚类方法的比较标准，然后从基于优化、关系、变换这样一个新的角度对聚类方法进行了分类和比较，最后对数据挖掘中常用聚类算法进行了分析，以便于人们更易于选择研究方向和选择适合于具体问题的聚类算法。     

坑柄井田南部延伸开采的环境地质评价

通过对坑柄井田南部原生地质环境，开采对工程地质环境和水环境影响的分析和评价，对可能出现的环境地质问题提出了预防对策。     

中外中小学数学教育之“长”“短”几则

根据比较教育学的原理和文化的多元性理论,列举事实,试图阐明：对中、外中小学数学教育的种种特点,往往不能简单地、轻易地概以“优点”或“缺点”,而盲目地“继承”或“拿来”,在中小学数学教育改革的过程中,必须始终坚持辩证唯物主义精神和实事求是的态度。     

The mechanical properties of stored red blood cells measured by a convenient microfluidic approach combining with mathematic model

The mechanical properties of red blood cells (RBCs) are critical to the rheological and hemodynamic behavior of blood. Although measurements of the mechanical properties of RBCs have been studied for many years, the existing methods, such as ektacytometry, micropipette aspiration, and microfluidic approaches, still have limitations. Mechanical changes to RBCs during storage play an important role in transfusions, and so need to be evaluated pre-transfusion, which demands a convenient and rapid detection method. We present a microfluidic approach that focuses on the mechanical properties of single cell under physiological shear flow and does not require any high-end equipment, like a high-speed camera. Using this method, the images of stretched RBCs under physical shear can be obtained. The subsequent analysis, combined with mathematic models, gives the deformability distribution, the morphology distribution, the normalized curvature, and the Young''s modulus (E) of the stored RBCs. The deformability index and the morphology distribution show that the deformability of RBCs decreases significantly with storage time. The normalized curvature, which is defined as the curvature of the cell tail during stretching in flow, suggests that the surface charge of the stored RBCs decreases significantly. According to the mathematic model, which derives from the relation between shear stress and the adherent cells'' extension ratio, the Young''s moduli of the stored RBCs are also calculated and show significant increase with storage. Therefore, the present method is capable of representing the mechanical properties and can distinguish the mechanical changes of the RBCs during storage. The advantages of this method are the small sample needed, high-throughput, and easy-use, which make it promising for the quality monitoring of RBCs.     

Thermophoretic collection of virus-laden (SARS-CoV-2) aerosols

Detecting the existence of SARS-CoV-2 in the indoor atmosphere is a practical solution to track the prevalence and prevent the spread of the virus. In this work, a thermophoretic approach is presented to collect the novel coronavirus-laden aerosols from the air and accumulate to high concentrations adequate for the sensitivity of viral RNA detection. Among the factors, the density and particle size have negligible effects on particle trajectory, while the vertical coordinates of particles increase with the rise in heating source temperature. When the heating temperature is higher than 355K, all of the particles exit the channel from one outlet; thus, the collecting and accumulating of virus-laden aerosols can be realized. This study provides a potential approach to accelerate the detection of SARS-CoV-2 and avoid a false negative in the following RNA test.     

跨境电子商务用户采纳行为的演化博弈研究

在大举推进跨境电子商务(以下简称"跨境电商")之前,用户对于跨境电商的采纳程度将是各国政府首要关注的焦点,决定着整个跨境电商交易主体之间的良性互动,进而真正实现跨境电商让利于民的美好初衷。本文通过对跨境电商交易双方(即品牌商与消费者)之间演化博弈模型的构建,对影响跨境电商用户采纳行为的因素及其关系进行系统研究,从而为进一步开拓跨境电商这片新蓝海提供科学依据。结果表明,影响跨境电商交易活动主体采纳的核心因素由初始投入成本、风险承担能力、超额收益的公平分配等要素构成,政府应努力建立一套有效的约束机制,使得海内外买卖双方在保持正常收益的同时,加强合作使风险最小化,并设法寻找到最佳的超额收益分配系数,以使跨境电商朝向合作共赢的方向演进。     

面向企业内部的财务预警管理系统研究

财务预警应当区分企业外部使用者和内部使用者建立不同的模型,研究的重心应当转移到企业内部应用上来;运用滚动预算、预警管理理论和信息技术,构建了一个面向企业内部的财务预警管理系统;详细阐述了该系统的构建思路、结构、原理模型、技术要点和应用方法。     

用于同步辐射X光束线的间接冷却T形单色器

设计了一种T形单色器冷却方案,相比传统的底冷方案,新设计中晶体面形可以通过参数优化得到控制.T形单色器冷却方案适用于功率密度 0.5W/mm2 以下,总功率在 1 0 0W左右的功率条件下     

基于结构方程模型对医学院校教师心理紧张反应的研究

影响心理紧张反应的因素有年龄、性别、学历、收入等个体特征,对支持利用度、时间控制、环境紧张因素、注意力需求、时间压力、合作需求、工作组织问题以及合作的可能性工作紧张因素,还有负性生活事件紧张因素都是影响教师心理紧张反应的主要因素。年龄越高,工龄越长、心理症状越明显,女性总体幸福感比男性低。工作紧张因素以及社会生活紧张因素都是影响其心理紧张反应的主要因素。     

外语资源网络利用平台的构建与实现

为给学生提供一个自主学习的网络学习环境,我们选择大学生最为关注、载体形式多样的外语学习资源为突破口,构建了外语资源网络利用平台。文章从平台的开发背景、总体框架与功能以及具体的实现方法等几方面介绍了整个构建过程。