降低直喷型柴油机的排放

本文以 4L22B直喷式自然吸气型柴油机为例进行了深入研究,通过改进燃烧室设计,调整喷油特性、喷油提前角等措施,使该机型排放满足欧I排放法规的要求,通过有效后处理装置使其排放接近欧II排放法规的要求。     

基于JSON格式的自定义组合条件查询设计与实现

查询模块在软件系统的开发中属于基本的必需模块,条件与对象属性相对应,而对象属性与表字段相对应,前台条件以And或者Or组装成JSON格式的数据,后台接受来自于前台的JSON数据进行一系列处理最终拼接为Hql字符串进而查询出满足条件的数据返回给前台展示。前台的查询条件组装成JSON格式数据借助于ligerui的ligerFilter插件,后台借助java代码对JSON格式数据进行处理。由于对象属性字段与数据表字段的对应采用了Hibernate映射框架,故在程序中对实体对象的操作相当于对数据库表的操作,这样简化了后台查询代码的编写工作,并且使得查询代码易于维护。     

一种扩展的基于角色的工作流访问控制模型

提出了一个扩展的基于角色工作流访问控制模型E WACM(Extended Workflow Access Control Model Based on Role).该模型提供细粒度的授权控制,使授权更为灵活,更符合工作流过程的需要,加入的时间参数使授权过程与工作流过程相互协调,实现最小特权原则.     

铝合金滚边仿真方法与工艺参数影响分析

为解决铝合金滚边过程中出现的难以成型、开裂等缺陷及验证铝合金包边模型和分析解决铝合金板件滚边过程中的所受应力大小问题,首先对固定型和压紧型两种滚边仿真建模方法的合理性进行对比研究。其次,在压紧边界条件下对铝合金滚边前的初始工艺参数—圆角大小、翻边高度、滚轮大小等因素对铝合金板件所受应力大小的影响进行了研究分析。结果表明,压紧型边界条件更符合实际滚边过程;通过选择合理的初始工艺参数,可以有效降低铝合金覆盖件滚边时所受应力大小。     

Theoretical photoelastic stresses in three dimensional body with elastic contact

An understanding of the Hertz contact theory is important for investigating the failure strength and behavior of rolling and/or slipping mechanical-structural components. Two simple special cases including a circular contact and line contact patch have been solved in the closed form solution. However, there are many unsolved complicated cases where the contact areas become elliptical contact patches. In this paper, a simple stress field generated in contact bodies under general loading conditions is derived. The stress field derived in this paper is utilized to generate theoretical three dimensional photoelastic isochromatic fringe patterns. Some of the theoretical isochromatic fringe patterns are compared with published experimental results. The agreement between the theoretical and the experimental results are found to be good.     

基于MRUP的中小型项目软件开发设计

近年来,随着大数据时代的到来,数据化运算影响着各个领域的各个方面。在我国,传统中小型项目软件开发设计方法存在项目要素条件引入域窄、项目预期效果逻辑评估性差、运算处理分析速度慢等问题。针对传统中小型项目软件开发设计方法的现状,提出基于MRUP的中小型项目软件开发设计方法,采用MRUP大数据引擎、动态MIFGL项目评估算法、多路径处理运算模组,形成一套完整的立体化方法设计。通过实验证明,提出的基于MRUP的中小型项目软件开发设计具有项目分析要素涵盖面广、分析处理速度快、项目预期评估准确率高的特点。     

Determination of permissible deviations of the two-sided arc welding conditions

Methods for determining the permissible deviations of welding conditions are investigated. The sensitivity parameters do not provide information on the relative risk of different types of perturbation of the parameters. A relative coefficient of transfer of perturbations is proposed which can be used to estimate the susceptibility of the welding parameter to perturbations and does not require any controlling effect of the system. An example of the application of the methods of determining the requirements for the accuracy of the parameter and the conditions for two-sided argon-shielded arc welding of sheets made of high-alloy steel without edge preparation is described.     

Rapid and robust resolution of Underwood equations using convex transformations

In this work, a new method is proposed for solving Underwood's equations. Newton methods cannot be used without interval control, and may require many iterations or experience severe convergence problems if the roots are near poles and the initial guess is poor. It is shown that removing only one adjacent asymptote leads to convex functions, while removing both asymptotes leads to quasi convex functions which are close to linearity on wide intervals. Using a change of variable, a pair of convex functions is defined; at each point within the search interval one of the two functions is guaranteed to satisfy the monotonic convergence condition for Newton methods. The search interval is restricted to narrow solution windows (simple and costless) and a simple high quality initial guess can be obtained using their bounds. Two solution algorithms are presented: in the first one, Newton (including higher-order) methods can be safely applied without any interval control using the appropriate convex function; in the second one, Newton iterations are applied to a quasi-convex function, and convex functions are used only if an iterate goes out of its bounds. The algorithms are tested on several numerical examples, some of them recognized as very difficult in the literature. The proposed solution methods are simple, robust, very rapid (quadratic or super-quadratic convergence) and easy to implement. In most cases, convergence is obtained in 2–3 Newton iterations, even for roots extremely close to a pole.     

Dense nuclei segmentation based on graph cut and convexity–concavity analysis

With the rapid advancement of 3D confocal imaging technology, more and more 3D cellular images will be available. However, robust and automatic extraction of nuclei shape may be hindered by a highly cluttered environment, as for example, in fly eye tissues. In this paper, we present a novel and efficient nuclei segmentation algorithm based on the combination of graph cut and convex shape assumption. The main characteristic of the algorithm is that it segments nuclei foreground using a graph‐cut algorithm with our proposed new initialization method and splits overlapping or touching cell nuclei by simple convexity and concavity analysis. Experimental results show that the proposed algorithm can segment complicated nuclei clumps effectively in our fluorescent fruit fly eye images. Evaluation on a public hand‐labelled 2D benchmark demonstrates substantial quantitative improvement over other methods. For example, the proposed method achieves a 3.2 Hausdorff distance decrease and a 1.8 decrease in the merged nuclei error per slice.     

高生物量富硒酵母的选育和培养条件的初步研究

对富硒酵母进行了选育并进行了条件优化，得到了摇瓶培养时富硒酵母的最适发酵条件：温度30℃，10％接种量，转速200r／min，发酵培养基最适初始硒浓度为25μg／ml，初始pH为4．0，发酵培养时间48h，经测定成品硒酵母生物量达到10g／L，硒含量超过1500μg／g，硒总含量超过15000μg／L，其中有机硒含量超过90％。