推进国家助学贷款与创新诚信教育

国家助学贷款已成为资助高校贫困生的主渠道,推进国家助学贷款工作,呼唤创新高校诚信教育,强化诚信教育应作为大学生思想道德教育的突破口,加强信用管理须设为防范贷款风险的"防火墙"。     

高校学生贷款制的国际比较与争议

随着世界各国高等教育收费制的纷纷出台 ,学生贷款制已成为学生资助的主要形式。大体上学生贷款的形式主要有抵押贷款和按收入比例偿还的贷款两种 ,贷款管理机构一般是高校或单独成立的自治机构和商业银行。世界各国对高校学生的贷款种类和形式略有不同 ,其实施效果也是迥异。由此引起了理论上与实践上的较大争议 ,特别是在发展中国家尤为明显。理论上争论的焦点集中在个人收益率是否大于社会收益率以及高等教育公平与效率问题。学生贷款在实践上的争议焦点是贷款实施的成本 -效益问题。对各国的学生贷款制进行比较研究 ,了解现时关于学生贷款的争议热点也许会给我国的学生贷款制研究带来一些启示。     

有效制度建设体系——秦冶重工制度建设实践

秦皇岛秦冶重工有限公司(见封面)是一家以钢铁企业为客户,以高炉炉顶、冶金阀门、冶金车辆和焦化设备为主导产品的知名冶金装备制造企业。公司原为国有企业,2004年改制。改制之后,公司取得较大发展,到2008年底,公司已有员工2000多人,投资参股企业9家,生产制造基地3处,年营业收入7亿元以上。但公司的制度建设工作却没有跟上经营发展,存在一定的问题,迫切需要改革。2009年之前,秦冶重工的制度建设工作主要存在以下问题:一是职责划分不明确,谈制度就是企业策划部的事,专业职能机构普遍认为制度建设不是其职能;二是制度缺失比较严重,不成体系,不能全面支撑经营管理;三是制度本身质量不高,可执行性不强,不适用的制度不能及时修订废止;四是制度建设工作缺乏激励约束机制,制度执行效果差。为了解决制度建设中存在的上述问题,提升规范管理水平,促进经营发展,从2009年开始,秦冶重工加强了制度建设,在制度建设方面进行了有益探索。经过3年多的探索实践,秦冶重工较好地解决了之前存在的问题,并形成了一个以组织体系为主体、制度体系为内容、技术体系为支撑、监查考核体系为驱动的促进并保障经营管理的有效制度建设体系。     

中国大学自主性的制度环境

大学自主性的制度环境是指决定、约束大学自主性活动的制度规则的总和。中国大学自主性的制度环境具有宏观鼓励与微观约束,制度剩余与制度匮乏,制度空间小于观念空间,民主法治传统的短缺与公民社会的不成熟等特征,正是这些特征导致中国大学自主性的现实特征。     

助学贷款：济困助学的有效途径

一、助学贷款概念的内涵及外延我们这里所指的助学贷款是指面向全体具有还款能力的学生，由本人自愿申请，银行在对个人的资信程度审核的基础上，以银行信贷的方式向学生发放贷款的学生资助形式。与传统的贷学金相比较，它具有以下特点：①信贷双方变成了学生和银行。学生直接向银行贷款，由银行负责有关信贷的全部事宜，改变了以前学生向学校申请，由学校内部发放贷款的方式；②个人助学贷款面扩大。当前的贷学金主要是针对贫困生而设立的，许多具有还款能力的学生被拒之门外，以银行信贷的方式使广大具有还款能力学生都能享受这一政策；③…     

基于综合约束的微小直线段速度连续规划算法

在刀具轨迹利用微小直线段进行表示的曲面高精高速加工中,存在以下几方面的约束:①相邻微小直线段之间的速度连续约束;②进给速度和端点剩余长度两者之间的相互约束;③符合给定加减速曲线的全局约束。在以上的约束条件下给出了微小直线段的速度连续规划算法,首先根据相邻直线段之间的几何关系,给出端点速度约束,根据端点速度与设定起跳数度的比较识别出高曲率点,并设置这些高曲率点为起跳点。然后在相邻起跳点之间进行一次全局速度规划,比较端点速度约束和一次全局约束的结果,调整每条直线段的起、末速度。随后根据逐步速度规划,包括前向速度约束和回溯匹配两个过程完成整个规划。根据以上算法,在软件数控系统上进行了试验,并给出了模拟和数值分析结果,表明能够应用于微小直线段的高速连续加工。     

基于滑移约束面方法的毛坯反求技术

由于一步逆算法在用于求解坯料展开问题中,并不能得到足够准确的毛坯,其计算误差会随着变形路径的复杂程度而变大.本文提出采用多步逆算法得到较为精确的毛坯形状及应力、应变分布.多步逆算法将成形过程分成几个工步进行模拟,并通过引入滑移约束面得到中间成形形状,采用牛顿-拉费森迭代将材料坐标和全局坐标中的残余应力转换到局部坐标.将此算法应用于油底壳的拉深计算,通过对比计算结果与实验结果,两步法得到的毛坯右端与实验结果十分吻合.多步有限元逆算法进一步提高了毛坯展开尺寸及应力分布的计算精度.     

基于特征约束语义的夹具自动装配技术研究

为提高夹具装配的准确性与效率,采用了一种基于特征约束语义的自动装配方法.该方法利用参数化技术建立夹具的三维模型元件库,定义了特征约束语义的描述方法.通过约束转换,用程序自动将基于特征约束的装配转换为基于几何约束的装配,从而实现快速装配.并开发了原型系统,验证了该方法的有效性.     

冲压工艺实例修改方法

提出一种冲压工艺实例修改方法,分两个阶段生成新冲压工艺方案。第一阶段,在旧工艺方案的基础上,根据新旧冲压件特征匹配对,进行特征之间的映射和转换,并且通过特征和刃口的关联,进行刃口的替换、删除和增加,自动生成新冲压工艺初始条料排样图;第二阶段,对已生成的初始排样图进行刃口修补,校核刃口间顺序约束、特征约束、最小工步约束和距离约束,并且仿照旧冲压工艺参数的计算方法重新计算新冲压工艺参数,从而生成最终工艺方案。并通过实例验证该方法的有效性。     

浅议政府采购制度

为了规范政府采购制度,我们应该发展和规范政府采购的代理机构;建立和完善政府采购制度的法律法规体系.选择适合国情的采购模式和采购方式;建立和完善政府采购制度保障措施.     

An attribute control chart using discriminant limits for monitoring process under the Weibull distribution

A new efficient process monitoring scheme has been developed for a process under which the quality characteristic follows the Weibull distribution. Recently control charts using discriminant limits for process monitoring for a normal distribution have been developed. But, there are many situations in which the distribution of underlying data is not normal. So, the application of such chart to a skewed distribution like the Weibull distribution may lead to erroneous conclusions. In this paper, an attribute chart using discriminant limits for the Weibull distribution has been developed. The parameters of the proposed chart have been determined by considering the in-control average run lengths. An example using the simulation data has been included for the practical use of the proposed scheme. It has been observed that the proposed chart is efficient for the quick detection of an out-of-control process. A real example from a healthcare area is also added to show the application of the proposed control chart.     

电磁半连续复合铸造轧辊的思路与实践

为了实现复合轧辊的顺序凝固，研制了电磁半连续复合铸造试验装置，利用该装置进行了一系列电磁半连续复合铸造试验，探索出了一套合理的电磁复合铸造工艺，制造了高铬铸铁／45#钢复合轧辊，并进行了装机试验。结果表明：电磁半连续复合铸造轧辊思路正确，装置简单合理，既实现了轧辊在复合过程中的顺序凝固，减少了铸造缺陷，又使复合界面达到良好结合，提高了轧辊质量和生产效率。     

新型活塞异形销孔加工方法的研究

简述了采用活塞异形销孔的必要性及其结构特点。提出一种新型活塞异形销孔数控加工方法，该方法采用一个基于压电陶瓷驱动的柔性铰链放大机构来实现镗刀的径向微位移。进行了异形孔加工过程中刀具运动特性分析，给出了柔性铰链刚度参数的设计方法，并进行了有限元分析。结果表明该方法适于异形孔的精密加工。     

Micro cutting in the micro lathe turning system

As an application of cutting for the manufacture of micro mechanical parts and as a trial of the development of a miniature machining system matching the micro size of the work piece, a micro lathe turning system has been developed. A work material 0.3 mm in diameter is clamped and cut to a minimum of 10 μm in diameter with a rotation speed up to 15,000 rpm. The whole size of the equipment is about 200 mm which can be set under an optical microscope. A micro diamond single point tool has been applied to the cutting of various shapes, and the usefulness of such a micro cutting tool for the various forms has been confirmed. Cutting force has been investigated using a three directional force sensor and the possibility of the reduction of resistant force to improve working accuracy and to apply to micro parts has been examined.     

Extracting dimensional information from steel reinforcing bars in concrete using neural networks trained on data from an inductive sensor

A new method is presented for extracting dimensional information from steel bars using images generated by an inductive sensor. The technique is based on the application of two feedforward backpropagation neural networks; one to estimate bar depth and the other to estimate bar diameter. Both of the networks have been trained on a set of data that consists of the peak parameters of six different bars scanned at 41 different bar depths. These input and target data must be pre-processed to obtain a good network generalisation. By testing the two networks with a completely different set of data, accurate performance has been obtained. Real, two-dimensional scan data have then been applied to both of the networks and the bar dimensional parameters have been extracted successfully. The advantage of the neural network method for extracting information is that it continues to operate reliably for very deep bars, for which the signal strength is severely attenuated and manifests a poor signal-to-noise ratio. Depth and diameter measurements have been obtained for bars located down to 58 mm, with errors that satisfy the requirements of the BS 1881 standard. At a depth of 40 mm, these measurements yield an error of ±4%, and this decreases as the depth reduces; in other words, the extracted bar diameter is within the requirements of the DIN 488 standard.     

新一代的溶液几何模型及其今后的展望

由二元系估算三元系和多元系的几何模型是当今在热力学和相图计算中用得最为广泛的一种溶液模型。但现有的这类几何模型由于假设了模型的设定与所处理的具体体系无关，结果造成了一些不可克服的固有缺陷，为了解决这个３０多年来一直存在的问题，我们摒存了这一不合理的假设而假定模型的设定应与所处理的体系有关。当我们引进了“相似系数”这一新概念以后，一种新的更合理的模型出现了。我们将这一类模型统称为新一代的几何模型。这     

Advances in optimisation of mechanical properties in cast TiAl alloys

The room temperature tensile properties of a number of cast TiAl-based alloys, which have been grain-refined either by additions of boron or by a new quenching and ageing treatment, have been assessed. It has been found that in the alloys which have been grain-refined by boron addition, the size of the titanium boride particles, which is strongly influenced by the size of the cast samples, is an important factor in limiting the tensile ductility. The tensile properties of samples which have been quenched and aged can be significantly improved and it has been shown that this grain refinement technique, which is based on the massive transformation, can be applied to a wide range of alloys. Quenching to above the ductile-to-brittle temperature, but below the temperature at which the massive transformation occurs, reduces the tendency for cracking during this type of heat treatment. The potential for producing cast components using these two approaches to grain-refinement is discussed.     

精密微塑性成形系统的研制

随着微型零件尺寸的减小,对成形设备提出了更高要求,传统的塑性成形设备难以在小行程下实现载荷和位移的精确控制。针对微成形的特点研制了精密微塑性成形系统,设计了宏动／微动相结合的驱动系统,微动部分使用压电陶瓷作为驱动器,宏动部分采用精密丝杠旋钮来实现,借助数据采集系统进行数据的实时采集和处理,使用成形工艺控制器对微成形过程进行精确控制,该系统可以对模具进行加热以实现等温成形,由温度PID控制器控制。使用该精密微塑性性成形系统进行了微成形试验,所成形的微型齿轮零件质量良好。     

Capturing Expert Knowledge for Supporting Design and Manufacturing of Injection Molds

Knowledge based approach is effective for renovating design and manufacturing processes. The objective of this paper is to investigate roles and usages of expert engineering knowledge in high-quality manufacturing, and to study a practical knowledge capturing method for realizing engineering support tools. An engineer oriented interface for a capturing method is proposed, and a flexible representation framework is studied for various types of expert knowledge. An integrated knowledge-based system has been developed for mold design support. The results have been evaluated by design and manufacturing of molds for cellular phones, and have shown substantial reduction of lead time for mold production.     

Qualification of parallel kinematics machines in high-speed milling on free form surfaces

Serial milling machines may one day find their limits in high-speed milling due to their limited dynamic characteristics. Indeed, the major drawback of a serial structure is that it consists of a pile of actuated joints; hence the mass on board for the axis underneath can be huge. This is mainly the reason why parallel structures are of interest in milling: in order to go faster.Such structures have been developed since 1980 for robotic tasks, while the first parallel kinematics machine tool appeared only 14 years later. Since then, very few papers have been published that deal with the potential of these structures in milling. The objective of this study is to show the potentialities of parallel structures in milling and especially in high-speed milling of free form surfaces, in comparison to serial structures. To do so, experiments have been realised on four serial kinematics machines (SKMs) and four parallel kinematics machines (PKMs). These experiments were of two kinds: either a real piece has been milled, or the output axis encoder data have been saved (this method of measurement has been previously developed in our team).So far, a comparison between the two structures (serial and parallel) has been possible, which permitted us to show that PKMs can provide interesting results in terms of time and precision. Hence, the goal of this study has been reached, as the PKMs potentialities in milling free form surfaces have been highlighted. With more experiments, a generalisation, by taking into account all the parameters (shape and material of the part, structure of the machine, etc.), will be attempted. In parallel, the development of our simulator for PKMs is necessary in order to be able to predict milling on these machines.