基于分形插值的改进趋势面拟合法在地面沉降中的应用

针对区域地面沉降监测点数量有限、分布不均的情况,一般采用空间插值的手段建立表面拟合模型来解决。基于分形插值,采用随机选择迭代函数的思想对传统的趋势面拟合法作出改进,改进后拟合优度系数提高0.03,达到0.995,且改进前后的拟合结果符合显著性检验的要求。实验结果表明:改进前后趋势面拟合法拟合结果满足地面沉降监测的精度要求,改进后方法的拟合优度更高,对现实地面沉降量变化的描绘更加真实,可为沉降灾害评价工作提供更准确的依据。     

An engineering method for complex structural optimization involving both size and topology design variables

This work presents an engineering method for optimizing structures made of bars, beams, plates, or a combination of those components. Corresponding problems involve both continuous (size) and discrete (topology) variables. Using a branched multipoint approximate function, which involves such mixed variables, a series of sequential approximate problems are constructed to make the primal problem explicit. To solve the approximate problems, genetic algorithm (GA) is utilized to optimize discrete variables, and when calculating individual fitness values in GA, a second-level approximate problem only involving retained continuous variables is built to optimize continuous variables. The solution to the second-level approximate problem can be easily obtained with dual methods. Structural analyses are only needed before improving the branched approximate functions in the iteration cycles. The method aims at optimal design of discrete structures consisting of bars, beams, plates, or other components. Numerical examples are given to illustrate its effectiveness, including frame topology optimization, layout optimization of stiffeners modeled with beams or shells, concurrent layout optimization of beam and shell components, and an application in a microsatellite structure. Optimization results show that the number of structural analyses is dramatically decreased when compared with pure GA while even comparable to pure sizing optimization.     

Design for comfort and social interaction in future vehicles: A study on the leg space between facing-seats configuration

With the advent of future vehicles, passengers expect to travel in comfort, and the free leg space between facing-seats could be an issue due to the unsuitability for all people, according to their anthropometric variability. A previous investigation survey showed the need to increase the leg-space between facing seats and, if installed, to improve the surface of the table placed in between. So, four different distances between seat-pans front edges of facing seats have been set-up and tested (44 cm, 51 cm, 58 cm, 65 cm) with a table in between. 13 couples of participants with different heights took part to experiments. The aim was to investigate the relationship between facing-seat distances and passenger wellbeing in terms of postural comfort and social interaction. Postural comfort has been analysed through optical tracking (for postural angles overtime) and questionnaires (perceived comfort). Social interaction feelings have been investigated with questionnaires. Experiment results showed the suitable distance could be 51 cm keeping the same table surface; otherwise, the 65 cm one could be ideal changing the table surface.Relevance to industryWith the advent of autonomous driving, vehicle manufacturers and designers are working hard to define new paradigms of public transportation in terms of seat layout, passenger wellbeing and interiors’ design. This paper contributes to increasing the general knowledge on the effects of distance between facing seats on postural comfort and social interaction.     

旱地西红柿种植技术

随着人民生活水平的提高,旱地西红柿种植面积逐年增大,但由于种植技术的缺乏,产量和质量均得不到提高。文章通过多年的研究,对西红柿从育苗、施肥、覆膜种植到管理进行了系统的阐述,有效提高山区人民旱地西红柿的种植水平,增加农民收入。     

Recent-onset ecstasy use: Association with deviant behaviors and psychiatric comorbidity.

Background: Despite increases in ecstasy (MDMA) use in the United States, little is known about characteristics linked with recent-onset ecstasy use, especially psychiatric symptoms and deviant behaviors. Aims: To test whether individuals with high levels of other drug use are more likely to be recent-onset ecstasy users; to test whether psychiatric symptoms in adults are associated with recent-onset ecstasy use; to explore the association between recent-onset ecstasy use and concomitant deviant behaviors in adolescents and adults. Methods: Data from the 2001 National Survey on Drug Use and Health. Findings: Recent-onset ecstasy use was significantly more likely to occur among adolescents and adults (18-34 years old) who engaged in deviant behaviors during the past year as compared with those who did not engage in deviant behaviors during the past year. Higher levels of deviancy indicated a higher likelihood of being a recent-onset ecstasy user, and associations were strongest with nonviolent deviant behaviors such as selling illegal drugs and stealing. Associations between deviant behaviors and recent-onset ecstasy use were similar in strength to associations between deviant behaviors and recent-onset cocaine and marijuana use, respectively. Adults who had past-year psychiatric symptoms (both depressive and panic symptoms) were twice as likely to be recent-onset ecstasy users as compared with those without past-year psychiatric symptoms. Greater levels of drug involvement increased the odds of being a recent-onset ecstasy user. Conclusion: Recent-onset ecstasy use seems to be associated with a range of other behavioral problems and may reflect one aspect of a larger problem behavior syndrome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

8VSB芯片的层次式设计方法

提出了深亚微米下系统级芯片层次式版图设计的方法，并用该方法设计了HDTV信道解码芯片8VSB的版图。实例设计结果表明，该方法在节约面积、加速时序收敛方面效果明显，大大缩短了芯片设计周期。     

大型往复式压缩机的配管设计

大型往复式压缩机功率大、占地面积大,管道振动问题也更为突出。笔者结合实践经验,对大型往复式压缩机的配管设计进行探讨,说明了平面布置与管道防振设计的密切关系,并介绍了管道防振设计的方法和步骤,以及相对简单的复杂管系气柱固有频率的转移矩阵计算方法。     

云南磷肥工业副产氟资源综合利用途径初探

根据云南磷肥工业发展情况 ,提出对磷肥工业副产氟资源综合利用的设想 ,并介绍目前国内已有的一些氟资源综合利用的工艺技术     

小流域氮流失特征及其影响因素

由非点源流失的氮是造成水体污染的主要因子之一，而土地利用方式往往对氮的流失产生重要影响。本课题在福建省九龙江流域遴选了4个不同土地利用方式的小流域，通过在自然降雨条件下现场采样与室内分析相结合，研究不同土地利用结构的小流域氮的流失特征和影响因素。研究结果表明：总氮、可溶态氮和泥沙结合态氮的浓度通常比径流先达到峰值，然后开始降低；氮的流失以可溶态氮为主(占73%～98.3％)，因此其流失量主要受径流量的影响与雨强关系不大；土地利用方式对氮的流失有明显影响，一般植被覆盖度提高可以降低流失，而农业活动会加剧流失；此外，在高植被覆盖度的天然林地，氮的流失呈现出以泥沙结合态为主。通过本研究可以看出土地利用结构的调整和合理布置是九龙江流域非点源污染控制的重点。     

乡镇供水工程设计中应注意的若干问题

乡镇供水作为水利开发建设中的一个新领域，设计工作是龙头，有许多技术问题需要研究和探索，阐述了乡镇供水工程设计应注意的若干问题，并对设计中存在的一些具体问题进行了分析和探讨。