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871.
872.
随着通航产业的蓬勃发展,轻型飞机已成为通用航空市场中非常具有发展潜力的机型,保障飞行安全对于轻型飞机的长远发展而言至关重要。弹道式整机降落伞救生系统作为飞行安全的最后一道防线,可大大提升驾驶员和乘客的旅程安全性。本文以西锐公司飞机配备的整机降落伞系统为研究对象,详细介绍了CAPS系统的设计验证、结构、工作程序、适用情况、使用条件和着陆考虑因素等方面,以期使相关专业设计人员对CAPS系统有一个较全面的认识,更好地把握整机降落伞系统的研究和发展方向。 相似文献
873.
OBJECTIVE: Speeding tickets are the most commonly used tool to deter speeders, yet little is known about how speeding citations affect individual drivers' behavior over time. This study examined the effects of being cited for speeding and types of legal consequences on drivers' subsequent speeding citations, which are an indicator of speeding behavior. METHODS: A cohort of 3,739,951 Maryland licensed drivers were identified and followed for one year. Drivers were categorized by whether or not they received a speeding citation in May 2002. Among those cited for speeding in May 2002, drivers were grouped by type of penalty (fines and points; probation before judgment [PBJ, which results in fines but no points]; or no legal consequences). The relative risks (RR) and 95 percent confidence intervals (CI) of receiving a speeding citation during follow-up were compared between drivers ticketed and not ticketed in May 2002, as well as among different penalty groups. Cox proportional hazards regression modeling was used to adjust for potential confounders, including age, gender, alcohol-impaired driving, and residence. Kaplan-Meier survival functions were used to examine timing of violations. RESULTS: Young drivers and male drivers were more likely to receive a speeding citation. Drivers who received a speeding citation in May 2002 had almost twice the risk of receiving a speeding citation during follow-up, compared with those not cited for speeding that month (RR 1.6, 95% CI 1.52-1.68). Overall legal consequences had no significant effect on the risk of receiving a repeat speeding citation relative to ticketed drivers who escaped those consequences (RR 0.98, 95% CI 0.84-1.15); however, stratified analyses showed a significant decrease in repeat citations among females (RR 0.75, 95% CI 0.63-0.90) and drivers who received PBJ (RR 0.81, 95% CI 0.67-0.96). Kaplan-Meier curves showed that the study group of speeders had a significantly shorter time between May 2002 until receipt of a speeding citation than controls. Among penalty groups, significantly shorter times until receipt of another citation were observed among drivers escaping consequences or receiving fines/points compared with drivers receiving fines/PBJ. CONCLUSIONS: Drivers who receive speeding citations are at increased risk of receiving subsequent speeding citations, suggesting that speeding citations have limited effects on deterrence in the context of the current traffic enforcement system. When comparing different penalties, PBJ is associated with a reduced rate of recidivism more than stronger penalties; however, it is unclear whether the reduction primarily is attributable to the penalty itself or to characteristics of drivers receiving PBJ. Increasing drivers' perceptions that they are at risk of being caught speeding may improve the effectiveness of speeding law enforcement. 相似文献
874.
XAD-8 resin isolation of organic matter in water was used to divide organic matter into the hydrophobic and hydrophilic fractions.
A pilot plant was used to investigate the change in both fractions during conventional and advanced treatment processes. The
treatment of hydrophobic organics (HPO), rather than hydrophilic organicas (HPI), should carry greater emphasis due to HPO’s higher
trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP). The removal of hydrophobic matter
and its transmission into hydrophilic matter reduced ultimate DBP yield during the disinfection process. The results showed that sand
filtration, ozonation, and biological activated carbon (BAC) filtration had distinct influences on the removal of both organic fractions.
Additionally, the combination of processes changed the organic fraction proportions present during treatment. The use of ozonation and
BAC maximized organic matter removal e ciency, especially for the hydrophobic fraction. In sum, the combination of pre-ozonation,
conventional treatment, and O3-BAC removed 48% of dissolved organic carbon (DOC), 60% of HPO, 30% of HPI, 63% of THMFP,
and 85% of HAAFP. The use of conventional treatment and O3-BAC without pre-ozonation had a comparable performance, removing
51% of DOC, 56% of HPO, 45% of HPI, 61% of THMFP, and 72% of HAAFP. The e ectiveness of this analysis method indicated that
resin isolation and fractionation should be standardized as an applicable test to help assess water treatment process e ciency. 相似文献
875.
经对鄂尔多斯市达拉特旗树林召镇的转基因试验林中的v系列转基因银中杨与非转基因对照组的生长性状的对比研究证明:该转基因系列具有较强的环境适应性,生长状况明显优于非转基因杨树。 相似文献
876.
通过现场测试对包钢中水水质类型及其用于高炉循环冷却系统的现状进行了调查研究。确定了在现有条件下4#高炉循环冷却水系统的水质类型为腐蚀为主,兼有结垢;包钢中水为微量结垢和腐蚀型水质,随着浓缩倍数的增加逐步转化为严重结垢型水质。 相似文献
877.
本文探讨了如何提高顶空气相色谱法测定三氯甲烷及四氯化碳的灵敏度、精密度与准确度。重点讨论了平衡条件的优化以及带顶空自动进器的气相色谱仪的各个关键参数的优化。 相似文献
878.
879.
Xiaoming Xu Jie Tang Zhaoyang Li Chang Liu Weizheng Han 《Mitigation and Adaptation Strategies for Global Change》2011,16(6):721-731
In this study, paddy fields in Jilin province which are flooded parcel of arable lands used for growing rice (Oryza sativa Linn.) were selected as the object. Long-term exploitation of paddy fields led to variations of soil organic carbon (SOC) and green
house gases (GHGs) emissions which might contribute to global warming. In order to calculate the amount of global warming
potentials (GWPs) of emissions from ricepaddies and find the correlations among rice yield, SOC storage and GWP, DeNitrification-DeComposition
(DNDC) model was used to simulate SOC densities and fluxes of main GHGs emitted from paddy fields. After verification, simulation
results were used to calculate SOC storages and 100-year GWPs from 1949 to 2009. Results indicated that SOC densities in depths
of 0–10 cm, 10–20 cm and 20–30 cm all kept increasing. Average methane (CH4) and nitrous oxide (N2O) fluxes were 278.55 kg carbon (kgC) ha−1 a−1 and 2.22 kg nitrogen (kgN) ha−1 a−1. The SOC storage (0–30 cm) had increased from 3.96 × 109kgC in 1949 to 47.85 × 109kgC in 2009. In addition, GWP emission was increasing exponentially in the past 61 years, from 0.16 × 106 Mg carbon dioxide equivalents (CO2-equivalents) to 66.36 × 106 Mg CO2-equivalents. Both SOC storage and GWP presented obviously linear relation to rice yields. Overall, the research suggested
that long-term rice yields could be used to estimate the SOC storage and GWP variations. 相似文献
880.