A New Approach to Predicting Forming Limits of Steel Sheet

A yield criterion utilizing five independent material parameters for representing the yield locus was proposed by Hill in l993. This paper describes an attempt to analyze forming limits of aluminum-killed (AK) steel sheet metal based on this criterion in conjunction with the M-K approach. Comparison of the predicted results with experimental data indicates that localized necking can be characterized only to a limited extent. However, material properties do not remain constant, but are deformation history dependent. Inclusion of deformation-dependent parameters in the analysis demonstrates a significant positive influence on forming limits. Comparison of predicted results with the experimental data underscores that the consideration of history-dependent material properties can improve forming limit predictions considerably.     

地下水主要组分水化学异常识别方法对比：以柳江盆地为例

地下水化学组分的异常识别是构建水化学背景值及开展人类活动影响程度识别量化的重要基础.以往提出的基于5种水化学图的主要组分异常识别方法取得了良好效果,但是该方法考虑的水化学图种类过多,计算复杂.为简化水化学图法,本文以柳江盆地为例,尝试采用Durov图替代5种水化学图,对地下水主要组分进行异常识别.为此,分别对比分析了水化学图与数理统计法组合出的7种异常识别方法的剔除效果,并进行方法可靠性检验.结果表明,数理统计法与水化学图法结合识别地下水异常相对于两者单独使用可以取得更好的识别效果;其中3σ准则+5种水化学图法和3σ准则+Durov图法对地下水主要组分异常识别效果最好;并证实采用Durov图可以有效替代5种水化学图进行地下水主要组分的异常识别,既保留了水化学识别异常的科学性,又大大简化了异常识别计算的过程.     

一种K干旱指数在西北地区春旱分析中的应用

用西北地区140个气象站1971～2000年的春季降水、蒸发资料,计算了一种K干旱指数,并制定了干旱标准,分析了西北春季干旱的气候特征。对K干旱指数与改进的Palmer干旱指数、降水距平百分率干旱指数作了比较分析;同时利用没有参加干旱指标划分的2001～2005年乌鲁木齐、玉树、兰州和西峰4个代表站(分别代表干旱、高原、半干旱和半湿润地区)的降水、蒸发独立样本资料对制定的干旱指标进行了检验。结果表明,新疆南部、甘肃西部、青海西部是重旱的高发区;新疆北部偏南地区、甘肃北部、南部和东部、宁夏北部、青海东南部、陕西北部是中旱的高发区;新疆西部、甘肃南部、青海西部、陕西东部是轻旱的高发区。K干旱指数对西北春季干旱有较好的监测能力;改进的Palmer干旱指数对干旱区的干旱监测效果好,但对高原、半干旱、半湿润地区的干旱监测有一定的局限;降水距平百分率干旱指数对轻旱和重旱监测效果好,对中旱监测能力差。在2001～2005年的检验中,再次证明改进的Palmer干旱指数对西北地区干旱监测有一定的局限,K干旱指数对西北地区的干旱监测有较好的效果。     

辽东湾沿岸水域甲肝病毒和粪大肠菌群分布

报道了2002年辽东湾3个沿岸海域表层海水中甲肝病毒和粪大肠菌群分布的检测结果。结果显示,5月份表层海水 中没有检出甲肝病毒,粪大肠菌群也符合卫生标准;8月份和10月份表层海水中的甲肝病毒loo％呈阳性,粪大肠菌群均超标。 结果表明,粪大肠菌群指示海水中肠道病毒污染程度仍具有很大程度的可靠性。     

Tool Path Planning for Avoiding Exit Burrs

Milling exit burrs usually form along the edges of a workpiece when the tool leaves the part while removing stock material. One of the most efficient methods for minimizing exit burrs is to prevent the tool from exiting the workpiece during material removal. This paper describes a systematic framework to generate tool paths that always enter a part, which is not a thin structure, in a planar milling operation. Three distinct tool exit conditions are analyzed for polygonal parts. A test criterion is then proposed to examine the occurrence of tool exits. For each condition, a tool path planning scheme is developed to avoid tool exits. These schemes are proved to be effective using the test criterion. This work is integrated into a networked manufacturing environment as a burr agent. Test parts are cut to demonstrate that this framework enhances edge quality by minimizing tool exits.     

以海岸带可持续发展为目标的战略环境评价

战略环境评价(SEA)就是对政策、计划/规划及其各种替代方案的环境影响进行规范的、系统的、综合的分析和评价过程.以海岸带可持续发展为目标的SEA应遵循与战略决策过程紧密结合、综合、多元评价标准及公众参与4个基本原则进行厦门岛东部海岸发展规划的战略环境评价案例研究.     

Technology-based industrial environmental management: a case study of electroplating in Shenzhen,China

Severe industrial pollution has largely hindered the sustainable development of China. Taking Shenzhen’s electroplating industry as a case, this article investigates the current status of the industry and proposes a specialized policy framework to push its environmental innovation. There is a relatively complete environmental management system in Shenzhen’s government, but it does not work well when dealing with the electroplating industry, mainly because it lacks regulation aiming at production technology, which is the underlying decisive factor of the environmental performance of the industry. So, we first develop an evaluation criterion, which incorporates a technological index about whether enterprises engage identified obsolete technologies. With this evaluation criterion, enterprises are classified into “advanced” and “obsolete”. Then, we propose specific policy suggestions for different types of enterprises, including command and control mixed with economic tools, voluntary agreements, establishing electroplating parks, and improving current management system. Finally, we assess the impact of the policy proposal and prove it to be conducive to the sustainable development of the industry and conclude it from a more general perspective.     

荷兰人体健康土壤环境基准与标准研究及其对我国的启示

土壤环境基准与标准是开展土壤环境保护与管理的基础. 荷兰是世界上较早开展污染土壤风险管控与土壤环境基准研究的发达国家之一,本文以荷兰为例,综述其土壤环境基准与标准研究,以期为我国土壤环境基准制定提供参考. 通过分析荷兰建立的有关土壤环境保护与管理的政策与法规,系统梳理已经制定的基于保护人体健康的土壤环境基准与标准,从人体毒理学基准、用地类型、暴露途径以及暴露参数四方面阐述荷兰土壤环境基准的制定方法,最后提出对我国土壤环境基准研究的建议. 荷兰较早制定了有关土壤修复的法案,形成了以土壤修复和可持续管理为主的法律体系,建立了以干预值和最大值为主的标准体系,并确定了土壤环境基准推导的理论方法. 我国应完善土壤污染防治的法规标准体系,开展符合区域具体情况、多种用地方式下的精细化土壤环境基准研究,加强本土化暴露评估模型研究,建立土壤环境基准数据库与优控污染物名录.      

基于潮汐时变特征的水质时空双重达标控制标准

潮汐河口水文、水质要素具有日内、月相周期性的时变特征,不适用恒定流的计算方法和评价标准进行水质达标控制,从而无法科学核定河口的水环境容量用于水污染防治管理。本文针对潮汐河口的非恒定往复流特性及水质的时变特征,提出了适用于潮汐河口水质达标控制的时、空双重控制标准;建立了钱塘江河口潮流水质模型,基于水质时空双重达标控制标准核定了各水功能区的环境容量。其中时间控制标准采用1d内超标小时数和月内超标天数两个指标控制,空间控制标准采用功能区空间平均水质、交界断面水质、混合区面积和敏感点水质等4项控制指标进行控制。水质时、空双重控制标准能够更全面更真实的反映潮汐河口水质达标情况,从而有效保护河口水资源水环境质量。其计算思路和方法可供相关水环境研究人员和环境管理人员借鉴。     

基于地理分区及神经网络的湖泊水库富营养化研究

构建了一个基于地理分区及神经网络的湖泊水库富营养化综合评价体系.以美国环境保护署Nutrient Criteria Database数据库为参照对象,有针对性地研究我国湖泊水库的情况,首次提出了基于地理分区的简易评价标准,对不同地理特征的水体富营养化临界值进行了定量研究.同时本研究还建立了基于神经网络的富营养化评价模型...     

青岛海滨疗养区环境噪声中的海浪声研究

本文提出海滨疗养区环境噪声为海浪声与海浪声为OdB时的环境本底噪声的合成,并介绍一种调查观测和实验方法,来分析海浪声L′及其对人的影响,着重分析了疗养房间开窗期间(5—9月份)海浪声与近岸风浪、涌浪、地形,海浪声强度、频谱与人的感受关系,研究结果表明,疗养人员对一般海况下的海浪声有好感和不受影响者在98％以上,影响睡眠的海浪声的发生率仅占2％以下,从而得出一般海浪声不应视为噪声且对人们有一定益处的结论,提出海滨疗养区环境噪声评价标准的建议。     

太湖流域水环境长效管理研究

流域长效管理现状不容乐观是造成太湖治理在投入大量人力、财力和物力后水质并无明显改善的重要原因之一。本文在深刻剖析太湖流域水环境长效管理存在问题的基础上,有针对性地提出了对策与建议。     

Evaluation of Bacterial Contamination as an Indicator of Viral Contamination in a Sedimentary Aquifer in Uruguay

In Uruguay, groundwater is frequently used for agricultural activities, as well as for human consumption in urban and rural areas. As in many countries worldwide, drinking water microbiological quality is evaluated only according to bacteriological standards and virological analyses are not mentioned in the legislation. In this work, the incidence of human viral (Rotavirus A, Norovirus GII, and human Adenovirus) and bacterial (total and thermotolerant coliform and Pseudomonas aeruginosa) contamination in groundwater in the Salto district, Uruguay, as well as the possible correlation between these groups of microorganisms, was studied. From a total of 134 groundwater samples, 42 (32.1%) were positive for Rotavirus, only 1 (0.7%) for both Rotavirus and Adenovirus, and 96 (72.6%) samples were positive for bacterial indicators. Results also show that Rotavirus presence was not associated with changes in chemical composition of the aquifer water. Bacteriological indicators were not adequate to predict the presence of viruses in individual groundwater samples (well scale), but a deeper spatial–temporal analysis showed that they are promising candidates to assess the viral contamination degree at aquifer scale, since from the number of wells with bacterial contamination the number of wells with viral contamination could be estimated.     

Ubiquity of parasporin-1 producers in <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> natural populations of Japan

Parasporin, a Bacillus thuringiensis parasporal protein, is unique in having a strong cytocidal activity preferential for human cancer cells. In this study, we characterized parasporin activities associated with three novel geographical isolates of B. thuringiensis. Parasporal inclusion proteins of the three isolates were highly toxic to human uterus cervix cancer cells (HeLa), but not to non-cancer uterine smooth muscle cells (UtSMC). Inclusions of the isolates lacked insect toxicity and hemolytic activity against sheep erythrocytes. Ouchterlony immunodiffusion tests revealed that the proteins of the three isolates are immunologically closely related to parasporin-1 (Cry31A), but dissimilar to the three other existing parasporin groups. Our results provide evidence that the parasporin-1-producing organism is a common member in B. thuringiensis populations occurring in natural environments of Japan.     

机场周围飞机噪声主要评价量合理性分析

简要阐述了现有机场飞机噪声主要评价量的优缺点，并通过对连续感觉噪声级LWECPN与昼夜等效声级LDN及其相互之间的内存关系的比较分析，推导了两者的差值计算公式，并用实例进行了计算，根据基于两个评价量的不同标准限值，得到分别以LWECPN与LDP。进行飞机噪声影响评价相差8dB以上的结果，但这并不意味着两者评价方法不同产生优劣矛盾，其实真正决定飞机噪声评价结果是否合理在于评价标准的限值大小。最后，提出了使飞机噪声影响评价更趋合理的建议。     

Prenatal sex diagnosis: Testosterone and fsh levels in mid-trimester amniotic fluids

We studied the validity of mid-trimester amniotic fluid testosterone and FSH in the diagnosis of fetal sex in abnormal fetuses and in twins. It was found that the testosterone/FSH ratio, but not the level of the individual hormones, was an excellent criterion for fetal sex diagnosis. In a control group of 32 female and 34 male fetuses, the testosterone/FSH ratio was diagnostic. In two cases the values were indeterminate and fetal sex could not be predicted, but there were no false diagnoses. The abnormalities of the fetuses were diagnosed by karyotype analyses or raised levels of α-fetoprotein. It was found that neither autosomal trisomies nor X-chromosome aneuploidy or neural tube defect interfered with the diagnostic value of the hormonal approach. The twin study included 14 pairs, three of whom were discordant for sex. In all twins the fetal sex diagnosis was appropriate. In co-twins of the same sex the hormone levels were very close to each other.     

刺激浮游植物生长的Fe对大气C沉降的影响

探讨了Fe对海洋浮游植物生长的影响过程和Fe在大气C沉降中的作用,作者认为:Fe不是浮游植物生长限制因子,而是浮游植物生长刺激因子;用Fe作为肥料,不仅不会降低大气中的CO2,还会相对增加大气中的CO2。Fe对浮游植物生长影响的研究过程给我们揭示了人类只能认识自然规律和变化过程以及运行的机制,而不能随意去改变它们。     

立贮固体发动机黏接界面剪切破坏风险研究

目的 评估长期立贮固体发动机黏接界面因剪切变形导致破坏的风险。方法 对固体发动机黏接界面剪切试件进行高温加速老化,而后对老化剪切试样进行定速拉伸剪切试验,依据剪切试验结果,总结固体发动机黏接界面力学性能的老化规律。基于Arrhenius方程外推得到固体发动机黏接界面考虑老化的剪切变形破坏判据,采用该破坏判据对立式贮存15 a的某型固体发动机黏接界面因剪切变形发生破坏的风险进行评估。结果 黏接界面在经过15 a的老化后,其最大剪切变形为0.792 6 rad,比初始性能下降5.31%。选定某型固体发动机进行长期立贮工况计算,仿真计算结果显示,该固体发动机立贮15 s时,黏接界面危险点处的切向应变值0.463 3 rad。该值小于老化15 a后黏接界面剪切变形破坏起始点,即该发动机在立式贮存15 a后,界面剪切变形程度未达到破坏阈值。结论 该破坏判据能够较为直观地对长期立式贮存固体发动机黏接界面因剪切变形发生破坏的风险进行评估,可为长期贮存固体发动机黏接界面结构完整性评估提供借鉴参考。     

经验强度准则确定有压隧硐上覆岩层最小厚度的方法

水工建筑中,据岩体的强度特性和内水压力的大小,精确确定有压隧硐上覆岩层最小厚度是非常重要的。文章在对经典方法进行评述的基础上,引入反映岩体非线性破坏特征的经验强度准则,视有压隧硐为内水压力和岩体初始应力联合作用的弹性体,据经验准则对岩体破坏的表述,理论推导了坚硬无裂缝岩体中有压隧硐上覆岩层最小厚度计算公式。最后,以简单算例说明文中方法。     

湿地泥沙环境动态评估方法及其应用研究——(Ⅰ)理论

通过类比相邻学科近年来发展的水体快速生物评估的思想，根据湿地泥沙自身的特点，提出了一种适用于湿地沉积物的环境质量评价方法－湿地（泥沙）沉积物环境动态评价方法。该方法主要用于湿地环境质量变化趋势的评价，其最大特色是可以对那些受人为活动影响较大的区域进行快速的动态评估。快速评估的目的在于加速环境质量评估过程，同时促进后续的管理决策进程。