新疆水资源开发利用与生态问题

新疆作为干旱区的典型省区,其气候条件、水分等自然因素决定了该省区是以内陆河流域为特征的生态系统。本文论述了该省区的自然生态条件及发展绿洲灌溉农业的生态变化,并陈述了生态变化导致的土地荒漠化为特征的生态问题。     

炼铜烟灰制取高纯度硫酸锌

采用炼钢烟灰制取高纯度硫酸锌,研究了制取条件对收率和产品质量的影响,试验结果表明,控制适宜的酸浸条件,锌浸取率≥９８％,铁浸取率可控制在０．０２％以下,当酸浸工艺条件液固比为３：１,温度８０－９０℃,硫酸加入量３９ｇ／Ｌ（酸浸液）滴酸时间１．５ｈ浸取时间２ｈ,再用空气和过氧化氢氧化除去溶液中的铁,产品中硫酸锌含量≥９９％,铁含量可降至０．５ｍｇ／Ｌ以下。     

软土中浅埋地铁车站结构的抗震性能分析

两侧采用粘弹性人工边界,底部为全约束,建立合理的土与地下结构相互作用模型,通过有限元软件分析,比较研究土—地下结构相互作用分析中埋深、土层分布和结构类型等因素对地下结构抗震性能的影响。结果表明,埋深对地下结构影响比较大,选择合适的地质土层和结构类型能大大提高结构抗震性能。     

Sex allocation in a monomorphic seabird with a single-egg clutch: test of the environment, mate quality, and female condition hypotheses

Sex allocation theory posits that mothers should preferentially invest in sons when environmental conditions are favorable for breeding, their mates are of high quality, or they are in good body condition. We tested these three hypotheses in rhinoceros auklets (Cerorhinca monocerata), monomorphic seabirds that lay a single-egg clutch, in 2 years that differed in environmental conditions for breeding. Results supported the environment and mate quality hypotheses, but these effects were interactive: offspring sex was independent of paternal traits in the poor year for breeding, while females mated to larger and more ornamented males reared more sons in the better year. Conversely, offspring sex was unrelated to female condition, as indexed by hatching date. We propose that good rearing conditions enable females to rear sons possessing the desirable phenotypic attributes of their mates. Results also supported two critical assumptions of sex allocation theory: (1) dimorphism in offspring condition at independence: daughters fledged with higher baseline levels of corticosterone than sons and (2) differential costs of rearing sons versus daughters: mothers rearing sons when environmental conditions were poor completed parental care in poorer condition than mothers rearing daughters in the same year and mothers rearing either sex when conditions were better. These novel results may help to explain the disparate results of previous studies of avian sex allocation.     

检测有机汞的标准物质氯化甲基汞的合成条件

选择两步法合成CH₃HgCl,即CH₃I与Hg通过光化学反应制得CH₃HgI,再使用AgCl将CH₃HgI转化为CH₃HgCl。以白炽灯作为光反应的光源;选用无水乙醇或丙酮或乙醚作为转化反应的溶剂,在进行转化反应操作时,必须加以搅拌;同时,确定在相应的溶剂中重结晶３次及操作条件。揭示了AgCl转化CH₃HgI的反应为固液异相反应,并确定了相应的溶剂。合成CH₃HgCl的熔点为169～170℃,元素分析的结果为C：4.89％、H：1.11％,与文献值一致。使用合成的CH₃HgCl配成标准溶液,测定得标准水样中汞浓度与标准值相等     

甲醇为共代谢基质时四氯乙烯的厌氧生物降解

四氯乙烯(PCE) 在厌氧条件下通过还原脱氯发生生物降解.本文研究以甲醇作为共代谢基质时PCE的降解情况.结果表明:在微生物的作用下PCE还原脱氯为TCE和DCEs,可能有VC和乙烯.因此,DCEs、VC和乙烯可能是PCE降解的终产物.PCE、TCE的降解和TCE的生成都符合准一级动力学.PCE和TCE的反应速率常数K分别为0.8991d^-和0.068 d^-;半衰期分别为0.77d和10.19d,TCE的生成速率常数为0.1333d^-.表明PCE的脱氯速度大于TCE,而TCE的生成速率大于降解速率,所以在整个实验期间都有TCE存在.     

Using thermal analysis with kinetic calculation method to assess the thermal stability of 2-cyanopropan-2-yliminourea

Azo compounds, which are commonly used as initiators and blowing agents, are also typical self-reactive materials capable of undergoing runaway reaction during storage and transportation, which can cause severe fires and accidents. To ensure the thermal safety of azo compounds in the process, transportation, and applications, this study investigated 2-cyanopropan-2-yliminourea, which can also be called V-30. First, thermal decomposition characteristics under the non-isothermal conditions were obtained using differential scanning calorimetry. Second, the collected data were combined with a mathematical model to evaluate the primary thermal hazard during the process for V-30. Then, based on a heat-transfer model, the self-accelerating decomposition temperature (SADT) was extrapolated for consideration and non-consideration of consumption of chemicals. The results showed that SADT of V-30 was less than 80 °C. Therefore, it is essential to avoid a temperature beyond SADT or the cooling system will fail. The influence of consumption was also considered for SADT in this study.     

基于小波包熵与AFSA-SVM的压力管道泄漏识别

为了快速、准确地诊断出输气压力管道不同的泄漏状态,提出了一种基于小波包熵与人工鱼群优化支持向量机(AFSA-SVM)相结合的压力管道泄漏模式识别方法。该方法首先对管道泄漏时产生的声发射信号进行小波包分解,并对分解的最后一层节点重构信号进行相关性分析,以获得敏感的节点信号。然后求取这些敏感节点信号的小波包熵值,作为管道不同泄漏信号的特征向量。最后将小波包熵值输入到SVM中,并运用AFSA方法对SVM分类器中惩罚因子C与核函数参数g进行全局优化,以提高其分类准确率。实验结果表明,该方法能准确地识别压力管道不同的泄漏状态,为天然气管道泄漏状态监测提供新方法。     

Impact of medical fitness to drive policies in preventing property damage,injury, and death from motor vehicle collisions in Ontario,Canada

Introduction: Drivers with medical conditions and functional impairments are at increased collision risk. A challenge lies in identifying the point at which such risk becomes unacceptable to society and requires mitigating measures. This study models the road safety impact of medical fitness-to-drive policy in Ontario. Method: Using data from 2005 to 2014, we estimated the losses to road safety incurred during the time medically-at-risk drivers were under review, as well as the savings to road safety accrued as a result of licensing decisions made after the review process. Results: While under review, drivers with medical conditions had an age- and sex-standardized collision rate no different from the general driver population, suggesting no road safety losses occurred (RR = 1.02; 95% CI: 0.93–1.12). Licensing decisions were estimated to have subsequently prevented 1,211 (95% CI: 780–1,730) collisions, indicating net road safety savings resulting from medical fitness to drive policies. However, more collisions occurred than were prevented for drivers with musculoskeletal disorders, sleep apnea, and diabetes. We theorize on these findings and discuss its multiple implications. Conclusions: Minimizing the impact of medical conditions on collision occurrence requires robust policies that balance fairness and safety. It is dependent on efforts by academic researchers (who study fitness to drive); policymakers (who set driver medical standards); licensing authorities (who make licensing decisions under such standards); and clinicians (who counsel patients on their driving risk and liaise with licensing authorities). Practical Applications: Further efforts are needed to improve understanding of the effects of medical conditions on collision risk, especially for the identified conditions and combinations of conditions. Results reinforce the value of optimizing the processes by which information is solicited from physicians in order to better assess the functional impact of drivers’ medical conditions on driving and to take suitable licensing action.     

Settle3D软件在半填半挖黄土路基变形分析中的应用*

为揭示半填半挖黄土路基的变形规律及其影响因素,为高填方黄土路基稳定性的评估提供科学依据。以国道G310典型半填半挖黄土路基为例,运用Settle3D软件对不同工况条件下的黄土路基进行精确建模与系统分析。结果表明:自然条件下路基左右侧沉降量差别不大,而降雨条件下原状黄土侧的沉降大于压实黄土侧的沉降,土层交界处沉降差异显著;降雨条件下中心点的沉降曲线在原填土交界处发生转折,表明压实效果显著;各施工阶段间沉降量差值呈非线性减小趋势,但降雨条件下的稳定时间更长。因此施工中控制路基压实度和采取合理的路基防水排水措施非常重要。