既有混凝土码头的时变氯离子扩散过程

为了研究不同暴露环境(大气区、潮差区和浪溅区)对氯离子在混凝土中传输的影响,以及氯离子扩散过程的时变特性,对北部湾某码头的混凝土现场耐久性进行了检测,得到了不同深度混凝土试样的自由氯离子浓度.结果表明,在同一侵蚀深度,浪溅区的氯离子浓度最大,潮差区的次之,大气区的最小,拟合得到的表面氯离子浓度和表观氯离子扩散系数亦表现出了相同特性;浪溅区是影响临海钢筋混凝土结构耐久性的最不利暴露环境;氯离子扩散系数随侵蚀时间递减,时间参数为服从正态分布的随机变量,大气区、潮差区和浪溅区时间参数的均值分别为0.19,0.36和0.43;在钢筋混凝土结构的耐久性分析中应考虑氯离子扩散系数的时变特性.     

两种不同结构的混合流体局部行波对流斑图

通过流体力学基本方程组的二维数值模拟,探讨了长高比?=20的矩形腔体中有较强Soret效应的混合流体对流中的局部行波的形成及含有缺陷的局部行波的动力学特性.当分离比?=?0.60时,在分叉曲线的鞍结分叉点附近相对Rayleigh数为r=1.926~2.074的范围内,出现了无缺陷局部行波.然后,随r逐渐增加,系统由无缺陷局部行波过渡到含有缺陷的局部行波并在r=2.075~2.224的范围内形成稳定的含有缺陷的局部行波.局部行波对流的宽度随r增加而增加,并在r=2.075处随着对流斑图的转变突然加宽.再随r增加,含有缺陷的局部行波失去稳定,对流控制整个腔体并演化成有缺陷的行波.有缺陷的局部行波是我们发现的新型对流结构.有缺陷的局部行波的形成依赖于局部行波的对流宽度.在具有缺陷的局部行波存在范围内,这种缺陷出现的周期随r增大而增加.     

长期权力感知对谈判结果的影响研究

为了探究个人长期权力感知对谈判结果的影响及作用机制,丰富和创新现有的谈判理论,针对实验被试者设计并实施了一次多事项模拟谈判实验;以实验测量所得的长期权力感知、首次报价、调节作用分别作为自变量、中介变量以及调节变量,探究长期权力感知对谈判结果的影响、首次报价所起到的中介作用以及调节定向的调节作用;结果显示长期权力感知与谈判收益之间具有正向相关关系,首次报价在过程中起到中介作用,但是调节定向的调节作用在其中却并不显著;基于以上研究,长期权力感知更强的谈判者会提出更高的首次报价,从而获取更好的谈判收益,调节定向的调节作用在以后的研究中有待进一步探究。     

农业科技示范园的规划设计初探

随着农业科技示范园的发展,其园区规划和发展需要相关原理及理论来指导,基于此,本文在总结该类园区特征的基础之上,提出了该类园区规划设计的基本原则及规划设计具体内容,科学合理的规划设计方法对园区的长远稳定发展起到了直接的指导作用。     

以典型产品带动专业课实践教学改革

介绍了金属材料专业课实践教学改革的思路和过程,围绕培养学生工程能力和创新精神,以典型产品带动专业课理论和实践教学,实现实践教学环节和内容的贯通,建立由多个环节有机组成的实践教学体系,通过综合性、工程性、设计性、创造性的实践教学,以科研生产促进实践教学开展,丰富和完善各个实践教学环节并突出能力培养,从而有利于学生提高工程实践能力及创新精神。     

Multifunctional artificial nacre via biomimetic matrix-directed mineralization

Natural nacre, one of the most studied biological structural materials with delicate hierarchical structures and extraordinary performance, has inspired the design and fabrication of artificial structural ceramics with high fracture toughness. However, to meet the diverse requirements of different applications, future structural materials must be multifunctional with superior mechanical properties, such as strength, hardness, and toughness. Herein, based on the matrix-directed mineralization method for producing biomimetic structural materials, we introduce nanoparticles with different inherent functions into the platelets of artificial nacre via the co-mineralization of aragonite and the nanoparticles. Besides their enhanced mechanical properties, the obtained artificial nacre materials also exhibit different functions depending on the type of the nanoparticles. To extend the versatility of this strategy, the effects of nanoparticles of different sizes and zeta potentials on mineralization are also analyzed. This universal strategy can be applied to the fabrication of other types of functionalized biomimetic structural ceramics that have potential applications in various fields, such as biomedical science.     

微生物燃料电池修复钒污染地下水的响应曲面优化研究

使用响应曲面法, 对单室微生物燃料电池去除五价钒的运行条件进行分析和优化。采用乙酸钠作为单室微生物燃料电池的碳源, 探讨钒初始浓度、COD初始浓度和电解液电导率对五价钒去除率的影响, 三因素三水平的响应曲面分析结果表明, 五价钒初始浓度对五价钒去除率的影响最显著, 其次为 COD 初始浓度, 最后是电解液电导率。利用响应曲面法得到最优实验条件: 五价钒初始浓度为75.44 mg/L, COD初始浓度为1007.48 mg/L, 电导率为11.98 mS/cm, 此时可获得五价钒的最大理论去除率80.31%。验证实验的结果证实了该优化方法的可靠性。研究成果可以促进微生物燃料电池技术在治理钒污染地下水领域的实际应用。     

An M-Objective Penalty Function Algorithm Under Big Penalty Parameters

Some classical penalty function algorithms may not always be convergent under big penalty parameters in Matlab software, which makes them impossible to find out an optimal solution to constrained optimization problems. In this paper, a novel penalty function (called M-objective penalty function) with one penalty parameter added to both objective and constrained functions of inequality constrained optimization problems is proposed. Based on the M-objective penalty function, an algorithm is developed to solve an optimal solution to the inequality constrained optimization problems, with its convergence proved under some conditions. Furthermore, numerical results show that the proposed algorithm has a much better convergence than the classical penalty function algorithms under big penalty parameters, and is efficient in choosing a penalty parameter in a large range in Matlab software.