基于CAE分析的汽车制动液罐注射模设计

分析了汽车制动液罐注射件的结构特点,使用Moldflow软件对制品的注射成型过程进行CAE分析,确定了模具的浇注系统和成型工艺条件。模具为三板式点浇口结构,采用嵌件抽芯、斜导柱抽芯和液压抽芯相结合的方式实现模具的抽芯要求,并在此基础上完成了模具设计。     

0.618法在一步成形模拟方法中的应用

合理地选择冲压件的毛坯外形 ,可以提高板料的成形性 ,同时也可以提高材料利用率。本文着重研究了一步成形模拟方法中松弛因子对收敛的稳定性和收敛效率的影响问题 ,提出了一种基于 0 618法的松弛因子优化算法 ,并且设计编制了计算程序。通过球冠、L形件、行李箱盖外板、T形件 4个算例 ,与一系列未经优化的固定松弛因子结果进行了比较 ,验证了此方法的有效性     

Medical specialists prefer to withdraw familiar technologies when discontinuing life support

OBJECTIVE: To assess how members of different specialties vary in their decisions about which form of life support to withdraw. The hypothesis was that each specialty would be more comfortable withdrawing its "own" form of life support relative to other forms and other specialties. DESIGN: Mail survey. SETTING: 24 medical centers. PARTICIPANTS: 225 specialists in six specialties and 225 comparison physicians randomly matched according to percentage of time devoted to clinical practice. MEASUREMENTS: The six specialties were linked with six life-sustaining technologies related to their special expertise: 1) pulmonologists with mechanical ventilation, 2) nephrologists with hemodialysis, 3) gastroenterologists with tube feedings, 4) hematologists with blood products, 5) cardiologists with intravenous vasopressors, and 6) infectious disease specialists with antibiotics. The subjects ranked different forms of life support in the order in which they would prefer to withdraw them. They also expressed their preferences in response to hypothetical clinical vignettes. RESULTS: In five of the six specialties, the specialists had a relative preference for withdrawing their "own" form of life support, compared with the preferences of the comparison physicians. Overall, the physicians tended to prefer withdrawing a form of life support closely linked with their own specialty. CONCLUSIONS: Just as some specialist physicians tend to reach for different technologies first in treating patients, they also tend to reach for different technologies first when ceasing treatment. Specialists' preferences for different ways to withdraw life support not only may reflect a special understanding of the limits of certain technologies, but also may reveal how ingrained are physicians' patterns of practice.     

“互联网+”背景下厨房系统的设计服务模式

目的构建"互联网+"背景下厨房系统的设计服务模式。方法在分析"互联网+"内涵的基础上,比较传统"微笑曲线"模式和"互联网+制造业"模式下工业设计切入模式的差异,构建"互联网+"背景下整体厨房云设计服务系统的功能目标、服务流程和生长模式。结论在"互联网+"背景下,厨房系统不仅实现了开放协同的定制设计,而且还实现了从产品形象一致性到用户体验一致性的设计转型,有助于快速创新和解决产能过剩问题。     

液体苯系物等类油物质吸附材料综述

近年来,苯系物等类油物质泄漏事故频发。由于苯系物多数具有极强的毒性和挥发性,因此苯系物比原油等重油泄漏事故引发的危害更大。考虑到苯系物和油类物质理化性质的相似性,对苯系物泄漏事故的应急处置办法可以参考溢油事故的处置办法。通过对溢油事故中常用的无机类吸附材料、有机高分子吸附材料和天然高分子吸附材料的研究现状和应用前景进行了综述,希望能够为相关科研工作者解决苯系物泄漏的应急处置提供思路,促进该领域的快速发展。     

Genetic effects of 1,3-butadiene and associated risk for heritable damage

A summary of the results of the studies conducted in the EU Project "Multi-endpoint analysis of genetic damage induced by 1,3-butadiene and its major metabolites in somatic and germ cells of mice, rats and man" is presented. Results of the project are summarized on the detection of DNA and hemoglobin adducts, on the cytotoxic and clastogenic effects in somatic and germinal cells of mice and rats, on the induction of somatic mutations at the hprt locus of experimental rodents and occupationally exposed workers, on the induction of dominant lethal mutations in mice and rats, and on heritable translocations induced in mice, after exposure to butadiene (BD) or its major metabolites, butadiene monoepoxide (BMO), diepoxybutane (DEB) and butadiene diolepoxide (BDE). The primary goal of this project was to collect experimental data on the genetic effects of BD in order to estimate the germ cell genetic risk to humans of exposure to BD. To achieve this, the butadiene exposure are based on data for heritable translocations and bone marrow micronuclei induced in mice and chromosome aberrations observed in lymphocytes of exposed workers. A doubling dose for heritable translocations in human germ cells of 4900 ppm/h is estimated, which, assuming cumulative BD exposure over the sensitive period of spermatogenesis, corresponds to 5-6 weeks of continuous exposure at the workplace to 20-25 ppm. Alternatively, the rate of heritable translocation induction per ppm/h of BD exposure is estimated to be approximately 0.8 per million live born, compared to a spontaneous incidence of balanced translocations in humans of approximately 800 per million live born. These estimates have large confidence intervals and are only intended to indicate orders of magnitude of human genetic risk. These risk estimates are based on data from germ cells of BD-exposed male mice. The demonstration that clastogenic damage was induced by DEB in preovulatory oocytes at doses which were not ovotoxic implies that additional studies on the response of mammalian female germ cells to BD and its metabolites are needed. The basic assumption of the above genetic risk estimates is that experimental mouse data obtained after BD exposure can be extrapolated to humans. Several points exist in the present report and in the literature which contradict this assumption: (1) the level of BMO-hemoglobin adducts was significantly elevated in BD-exposed workers; however, it was considerably lower than would have been predicted from comparable rat and mouse exposures; (2) the concentrations of the metabolites DEB and BMO were significantly higher in mouse than in rat blood after BD exposure. Thus, while metabolism of BD is qualitatively similar in the two species, it is quantitatively different; (3) no increase of HPRT mutations was shown in 19 workers exposed on average to 1.8 ppm of BD, while in a different population of workers from a US plant exposed on average to 3.5 ppm of BD, a significant increase of HPRT variants was detected; and (4) data from cancer bioassays and cancer epidemiology suggest that rat is a more appropriate model than mouse for human cancer risk from BD exposure. However, the dominant lethal study in rats gave a negative result. At present, we do not know which BD metabolite(s) may be responsible for the genetic effects even though the bifunctional alkylating agent DEB is the most likely candidate for the induction of clastogenic events. Unfortunately, methods to measure DEB adducts in hemoglobin or DNA are only presently being developed. Despite these several uncertainties the use of the mouse genetic data is regarded as a justifiable and conservative approach to human genetic risk estimation given the considerable heterogeneity observed in the biotransformation of BD in humans.     

The syndrome of depressive depersonalization

Nineteen patients (9 men, 10 women aged 22--38 years) with depressions were examined. The phenomena of anesthesia of ideatoric functions dominated in clinical picture of such depression. This depression is defined as the depression of estrangement. Psychopathologic differentiation of mental estrangement in the structure of depression and in similar disorders of self-consciousness which were formed in depressions under conditions of "transitional syndrome" (according to G.Gross) is outlined. This syndrome is characterised by irreversible negative disorders of "defective depersonalization". The following signs permit to distinguish depression of estrangement from "transitional syndrome": partiality of the estrangement's phenomenon; connection between psychopathologic formations and pathology of imagination (figurative expressiveness, demonstrativity, lability to psychogenic and medical actions); conformity of the syndrome's structure and characteristics of premanifested personality's structure (combination of hyperthymic features with histrionic and/or narcissic ones). "Apperceptive anesthesia" is suggested for designation of the variant of the depression described.     

iDCX 51在Webit上的设计与实现

Webit是一个独立的、低成本的网络服务器,由东大新业技术股份有限公司研制成功.iDCX 51是Intel公司开发的实时操作系统,在工业控制等领域已成功应用,为使其能在Webit中也能够运行,以增强Webit的性能,对此本文以Webit内部单片机AT90S8515为例介绍iDCX 51往Webit中移植的设计与实现,并对移植后的时间性能进行了测试与对比分析,得知其任务切换时间与最大中断禁止时间这两项关键的时间性能指标分别减少33.3%和31.9%,表明系统移植后实时性得到了提高.     

单级倒立摆建模及其控制方法设计

单级倒立摆控制是一个即复杂而又对准确性、快速性要求很高的非线性不稳定系统控制问题。单级倒立摆数学模型的建立对研究其稳定性具有指导作用。用拉格朗日功能平衡法建立了倒立摆的刚体动力学方程,采用了LQR法对其进行了控制设计,并且进行了MATLAB仿真,结果表明此方法均可以成功控制倒立摆,使其稳定并具有良好的鲁棒性。     

基于ANSYS的汽车排气消声器改进设计

建立消声器的ANSYS仿真模型,分析原消声器的消声性能,通过建立三维仿真模型,研究两腔串联的复杂式结构消声器的消声性能,结果表明,改进后增加了消声器低频带的宽度和中频范围内的消声量,同时稳定高频振荡,但在1 550 Hz和2 300 Hz仍存在问题,加入端部共振腔后,低频段的消声量明显增加,2 300 Hz高频带得到改善.