大学生羞怯与手机成瘾倾向:孤独感的中介作用

为探讨大学生羞怯与手机成瘾倾向的关系,考察孤独感在大学生羞怯与手机成瘾倾向之间的中介作用。采用羞怯量表、UCLA孤独量表得分第三版和大学生手机成瘾倾向量表对在贵州省8所高校抽取的1 147名大学生进行调查。结果显示:大学生羞怯量表得分、孤独感量表与手机成瘾倾向量表得分显著正相关(r=0.27,r=0.29,均P<0.001),羞怯量表得分和孤独感量表得分显著正相关(r=0.49,均P<0.001);羞怯和孤独感均可显著正向预测大学生手机成瘾倾向(均P<0.001),孤独感在大学生羞怯与手机成瘾倾向之间的部分中介作用成立。     

从科学走向艺术--浅论21世纪中国手机造型设计

文章对手机、造型及其造型设计等相关概念作了一个初步的阐释 ,着重就中国手机及其造型设计所面临的机遇和挑战进行了剖析 ;阐述了中国手机造型要实现艺术化设计的观点 ,即从科学走向艺术。     

Heuristic Solution Methods for the Multilevel Generalized Assignment Problem

The multilevel generalized assignment problem is a problem of assigning agents to tasks where the agents can perform tasks at more than one efficiency level. A profit is associated with each assignment and the objective of the problem is profit maximization. Two heuristic solution methods are presented for the problem. The heuristics are developed from solution methods for the generalized assignment problem. One method uses a regret minimization approach whilst the other method uses a repair approach on a relaxation of the problem. The heuristics are able to solve moderately large instances of the problem rapidly and effectively. Procedures for deriving an upper bound on the solution of the problem are also described. On larger and harder instances of the problem one heuristic is particularly effective.     

A covering construction for packing disjoint copies of the Hoffman‐Singleton graph into K50

In this note we show how coverings induced by voltage assignments can be used to produce packings of disjoint copies of the Hoffman‐Singleton graph into K₅₀. © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 408–412, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jcd.10049     

工程施工中运输网络优化方案

施工工地运输方案的优化设计可以归结为 :按施工期要求设计运输线路或验证已有线路通行能力 ,计算总线路中影响提高流量的关键路段 ,取得最小费用最大流 .本文运用图论理论这一数学工具把实际问题抽象为有向网络 ,进而建立数学模型 .此方法理论上严密 ,解题步聚直观清晰 ,对水利、公路、水路、铁路等其它运输系统有普遍意义 .     

Assignment of conformation-sensitive near-infrared bands in high-spin ferrous haemoproteins. Low-temperature magnetic circular dichroism data

An assignment of the near-infrared bands in the 600–800 nm spectral region observed in magnetic circular dichroism (MCD) spectra of high-spin ferrous haemoproteins is presented. The assignment is based on a relative energy level scheme for iron d-electrons, a comparison of predicted and measured temperature dependences of MCD intensity, a sign of MCD bands and a group theoretical analysis of allowed transitions. The proposed assignment is consistent with the ∼15-nm red shift of the ∼760 nm band on breakage of the Fe-His bond in deoxy-myoglobin at low pH, with low-temperature photolysis experiments available for CO complexes of several haemoproteins. In accordance with the observations, the intensity of the MCD bands for proteins with a sulphur anion of cysteine as proximal haemligand (cytochrome P450 and chloroperoxidase) is predicted to be diminished by at least one order of magnitude compared to that for proteins with an imidazole of a histidine as a protein-derived haemligand (i.e. myoglobin, haemoglobin and horseradish peroxidase). Received: 4 February 1997 / Accepted: 1 May 1997     

Adaptive remeshing for ductile fracture prediction in metal formingRemaillage adaptatif pour la prévision de la rupture ductile en mise en forme

The analysis of mechanical structures using the Finite Element Method in the framework of large elastoplastic strain, needs frequent remeshing of the deformed domain during computation. Indeed, the remeshing is due to the large geometrical distortion of finite elements and the adaptation to the physical behavior of the solution. This paper gives the necessary steps to remesh a mechanical structure during large elastoplastic deformations with damage. An important part of this process is constituted by geometrical and physical error estimates. The proposed method is integrated in a computational environment using the ABAQUS/Explicit solver and the BL2D-V2 adaptive mesher. To cite this article: H. Borouchaki et al., C. R. Mecanique 330 (2002) 709–716.     

A note on a polynomial time solvable case of the quadratic assignment problem

We identify a class of instances of the Koopmans–Beckmann form of the Quadratic Assignment Problem that are solvable in polynomial time. This class is characterized by a path structure in the flow data and a grid structure in the distance data. Chr18b, one of the test problems in the QAPLIB, is in this class even though this feature of it has not been noticed until now.     

预测我国钢铁工业发展趋势的递归模型

本文根据我国钢铁工业生产特点,建立了60多个变量、28个方程的递归模型,描述了钢铁工业生产的结构形式,确定了主要生产环节的生产函数,给出了各种经济变量间的相互关系,预测了我国矿、铁、钢、钢材、产值等28个主要的内生变量的未来值,分析了“七五”、“八五”、“九五”三个五年计划可达指标、发展速度及保证条件。经过1984年的实际检验,证明模型的预测效果良好。     

基于移动Agent技术的医学图像检索方法

针对现有医学图像检索方法中，检索算法速度较慢、准确性较低以及远程检索时占用大量带宽等问题，设计并实现了一种基于移动Agent技术的医学图像检索方法，重点讨论了该方法实现的关键技术，包括提升框架下的M带整数小波变换和提取多通道纹理特征的检索算法．模拟实验结果表明，该方法实时性较强，占用网络带宽较少，采用的算法运算速度提高近10倍、运算复杂度降低约50％，提取的纹理特征能充分表达图像内容，较好地满足了医学图像的检索要求，实现了对医学图像库快速较准确的检索．