蒙脱土增强热塑性淀粉性能的研究

用蒙脱土(MMT)作增强剂、甲酰胺和尿素为混合塑化剂制备了MMT增强热塑性淀粉(MTPS)。用扫描电子显微镜(SEM)、万能实验机和热重分析法(TG)对MTPS进行了结构表征和性能测试。SEM表征结果说明,MMT可均匀分散在热塑性淀粉(TPS)中,MMT和TPS有良好的界面结合。力学性能测试结果表明,w(MMT)=0-30％时,MTPS拉伸强度达到23.415MPa,断裂伸长率从112.522％降至21.421％,屈服应力从3.172MPa上升至17.204MPa,屈服应变从31.221％降至4.471％,杨氏模量达到531.114 MPa,断裂能从2.033 N·m下降到1.414 N·m。该材料的耐水性能和热稳定性均高于纯TPS。     

On-machine interlocking of 3D laminate structures for composites

By using an adjacent-layer interlocking method on a weaving machine, multi-layer preform structures are developed. The on-loom interlocking method eliminates the yarn breakage resulting from needle penetration which is the case for off-loom interlocking of fabric layers. The concept of this three-dimensional (3D) fabric design is to bind each pair of adjacent layers at one connecting point in every other plain-weave repeat within each layer. The mechanical properties of the resulting composites are investigated by means of impact, short-beam shear and the long-beam flexural testing. The failure mechanisms found in 3D on-loom interlocked composites include fiber breakage, fiber debonding and fiber pull-out.     

Simulated Annealing and the Generation of the Objective Function: A Model of Learning During Problem Solving

A computational model of problem solving based on significant aspects of human problem solving is introduced. It is observed that during problem solving humans often start searching more or less randomly, becoming more deterministic over time as they learn more about the problem. This two‐phase aspect of problem‐solving behavior and its relation to learning is one of the important features this model accounts for. The model uses an accelerated simulated annealing technique as a search mechanism within a real‐time dynamic programming‐like framework upon a connected graph of neighboring problem states. The objective value of each node is adjusted as the model moves between nodes, learning more accurate values for the nodes and also compensating for misleading heuristic information as it does so. In this manner the model is shown to learn to more effectively solve isomorphs of the Balls and Boxes and Tower of Hanoi problems. The major issues investigated with the model are (a) whether such a simulated annealing‐based model exhibits the kind of random‐to‐directed transition in behavior exhibited by people, and (b) whether the progressive discovery of the objective function, even when given very little or poor initial information, is a plausible method for representing the learning that occurs during problem solving and the knowledge that results from that learning.     

预应力混凝土结构设计中几个问题的探讨

提出了等效荷载的简化计算方法，分析了在不同情况下考虑预应力筋作用的不同方法，建议在建筑结构中利用抗弯预应力筋来承担部分扭矩，以提高材料的使用效率。     

北京科技会展中心预应力混凝土板开洞技术研究

北京科技会展中心由于使用功能的改变 ,需在裙房部分 1、2层顶板增加商用扶梯 ;因此需对原结构进行开洞处理。开洞尺寸分别为 3 2m× 7 4 5m和 3 2m× 12m ;本文从板底支撑的搭设、混凝土板的分段剔凿、预应力筋的切断放张、张拉端面加固处理和重新张拉等方面对预应力混凝土板的开洞做了详尽的阐述     

Dopamine and reward: Comment on Hernandez et al. (2006).

Many lines of evidence suggest that the dopaminergic projection from the midbrain tegmentum to the forebrain must play a critical role in mediating the behavioral effects of natural and artificial rewards, with brain stimulation reward and addictive drugs included in the latter category. However, a closer look reveals many incongruities. The work of G. Hernandez et al. (2006; see record 2006-09890-013) resolves several puzzles. It implies that the dopaminergic projection does not carry the signal that encodes the magnitude of a brain stimulation reward. It suggests that the elevation in the tonic levels of dopamine consequent on brain stimulation reward modulates the registration of the magnitude of the reward. This reconciles the psychophysical evidence with the pharmacological, electrophysiological, and anatomical evidence. However, some serious puzzles do remain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

抗震钢筋对高拱坝抗震性能的影响

依据小湾拱坝伸缩横缝间布设抗震钢筋方案、特点和要求,围绕抗震钢筋对大坝抗震的影响展开研究,内容包括抗震钢筋种类的选择、温度影响、配筋方式、部位、数量的布设、方案的效果检验及其优化、以及布设预应力钢束的效果等,并提出了这些抗震措施对坝体横缝张开度的影响。研究结果认为在提供上、下游面各布设6层含钒抗震钢筋能有效减小地震时上游横缝的张开度,采用穿越横缝的抗震钢筋是有效的抗震措施。     

Developments in the measurement of reinforcement strain distributions in reinforced concrete members

A technique is described for measuring in detail the longitudinal strain distribution along the reinforcement of reinforced concrete members by means of strain gauges installed in a central duct within the reinforcement. Results of a preliminary test are given.     

汉江堤防白蚁的危害与防治

汉江流域气候温和，土质、植被适宜白生长。蚁害威胁到汉江河道堤防的防洪安全和两岸千百万人民的生命财产安全，必须严加防治。其治理办法有挖，寻，灌，烟熏等。施毒烟熏灭蚁行之有效，能省工省力、节省省金，但仍须加强认识，制订规划，配备人员，进行防治技术的科研与创新。     

Reinforcement and Binet Performance in Disadvantaged Children.

Test-taking motivation has been viewed as an important determinant of the attenuated IQ scores of disadvantaged children. This study compared the effect of a material reward (money) and the symbolic reward generally used (praise) in the test-taking situation on Binet IQ scores of severely disadvantaged fourth-grade children. Forty-six boys and 46 girls were administered the Stanford-Binet Intelligence Scale, Form L-M, with either material reward (money) or symbolic reward (praise) for correct responses. The IQ scores of the four groups, constituted on the basis of reward condition and sex, were compared. Results indicated no IQ difference due to reward and no interaction between reward and sex. Boys made significantly higher IQ scores than did girls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)