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181.
S. Koppel J. L. Charlton P. Hua P. Y. Liu H. Pham K. Stephan 《Traffic injury prevention》2018,19(8):S173-S175
AbstractObjective: The current study investigated whether older drivers’ driving patterns during a customized on-road driving task were representative of their real-world driving patterns.Methods: Two hundred and eight participants (male: 68.80%; mean age?=?81.52 years, SD?=?3.37 years, range?=?76.00–96.00 years) completed a customized on-road driving task that commenced from their home and was conducted in their own vehicle. Participants’ real-world driving patterns for the preceding 4-month period were also collected via an in-car recording device (ICRD) that was installed in each participant’s vehicle.Results: During the 4-month period prior to completing the on-road driving task, participants’ median real-world driving trip distance was 2.66?km (interquartile range [IQR]?=?1.14–5.79?km) and their median on-road driving task trip distance was 4.41?km (IQR?=?2.83–6.35?km). Most participants’ on-road driving task trip distances were classified as representative of their real-world driving trip distances (95.2%, n?=?198).Conclusions: These findings suggest that most older drivers were able to devise a driving route that was representative of their real-world driving trip distance. Future research will examine whether additional aspects of the on-road driving task (e.g., average speed, proportion of trips in different speed zones) are representative of participants’ real-world driving patterns. 相似文献
182.
The annual relative mass of storage organs cycle of Bufo gargarizans in southwestern China was studied from December 2005 to November 2006. We described how those organs changed in response to extreme temperatures. Energy reservation dropped to the lowest levels after dormancy for both sexes, and then increased for period of 4.25 month. However, the mass of these organs dropped again rapidly until August (liver) and September (fat bodies) due to the constraint from extreme high temperature occurred during the summer, and then non-significantly increased before hibernation. For ovaries, varied with a different profile to those of liver and fat bodies have a resting period of four months. In addition, the toads’ ovaries kept growing when the mass of liver and fat bodies declining accordingly during hibernation. Therefore, ovarian mass increased during the hibernation and non-hibernation period. 相似文献
183.
道路交通噪声预测声源简化研究 总被引:1,自引:1,他引:0
为了分析《环境影响评价技术导则声环境》(HJ 2.4—2009)中将道路声源简化为1条位于道路中心线处的线声源与按照车道数简化为多条线声源之间的误差,针对不同宽度的道路,推导了多条线声源与1条线声源在接收点噪声影响的误差计算公式,并基于Predictor-lima预测软件预测和现场噪声衰减规律实测进行了验证。研究结果表明,对于接收点到道路边缘的距离大于道路宽度的情况,可简化为1条线声源;对于接收点到道路边缘的距离小于道路宽度的情况,应按照车道数简化为多条线声源。 相似文献
184.
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186.
中国城镇建设用地经济密度的区位差异及影响因素——基于273个地级及以上城市的分析 总被引:4,自引:0,他引:4
以全国地级及以上城市中的273个样本城市为研究对象,分别从全国、沿海地区、内陆地区三个层次考察了样本城市城镇建设用地经济密度的区位差异。根据柯布-道格拉斯生产函数的理论与分析方法建立模型,分析了资本、劳动力、土地三大投入要素和城市全要素生产率等对城镇建设用地的影响,并在控制以上变量的条件下侧重考察了城市区位差异的影响。发现我国城镇建设用地经济密度的区位差异明显,具有区位优势的城市土地效益平均高于缺乏区位优势的城市;沿海水陆口岸的区位优势十分显著,建设用地经济密度相对较高,而内陆地区水陆口岸的区位优势有待发掘;航空口岸对提高城镇建设用地经济密度未发挥积极作用。分析结果表明,生产要素投入、科技水平、市场环境和城市发展阶段是影响土地效益的主要因素,但不同区位条件下城镇建设用地经济密度的影响因素有所不同,为提高城镇建设用地经济密度,不同区位条件的城市着力点应各有侧重。 相似文献
187.
Agricultural Productivity Changes Induced by the Sloping Land Conversion Program: An Analysis of Wuqi County in the Loess Plateau Region 总被引:3,自引:0,他引:3
This paper examines the agricultural productivity change induced by the Sloping Land Conversion Program (SLCP) using the Malmquist
index method and household data collected from Wuqi. We find that during the period of 1998–2004, the total factor productivity
(TFP) grew by 15.8%. While numerous households suffered a TFP decline, the majority of them experienced a large gain. By decomposing
the TFP, we further show that its increase is due exclusively to the improvement of technical efficiency rather than to technological
change. To validate these findings and put them in perspective, we also estimated the TFP change with county-level aggregate
data. It is revealed that driven by technological change and scale efficiency, the TFP grew slightly during the period of
1992–1998. Because of the tremendous cropland reduction and production mode shift caused by implementing the SLCP, the TFP
declined substantially during the first three years of the program; due to continued improvement of technical efficiency;
however, its growth accelerated later. Altogether, our evidence consistently suggests that implementing the SLCP has contributed
to the agricultural TFP growth in the longer term and that the efficiency improvement has resulted mainly from the increased
public expenditures for extension services and diffusion of technical knowledge. Wuqi’s experience proves that it is possible
to achieve environmental conservation and increase productivity simultaneously, even when facing a cropland reduction and
production mode alternation. 相似文献
188.
高膜通量厌氧微网生物反应器处理生活污水的研究 总被引:3,自引:1,他引:2
将动态膜技术与厌氧膜生物反应器相结合,形成一体式厌氧微网生物反应器(AnFBR),用于城市生活污水的处理,研究了在高膜通量条件下,AnFBR的运行情况和对生活污水的处理效果。结果表明,AnFBR在膜通量为72 L/(m2.h)条件下可连续稳定运行40 d;系统对COD平均去除率为58.4%,对TN和NH3-N有一定的去除效果;出水SS最高为15.0 mg/L,出水中污染物粒径在10μm以下;微网动态膜对小分子物质的截留量不高,但对分子量大于1 000 kU的物质有明显的截留效果,进水中的大部分大分子物质被转化为小分子物质;AnFBR在保留了泥水分离特点的情况下还具有结构简单、膜通量高、微网过滤周期长等优点。 相似文献
189.
Renbin Zhu Yashu Liu Hua Xu Tao Huang Jianjun Sun Erdeng Ma Liguang Sun 《Atmospheric environment (Oxford, England : 1994)》2010,44(3):304-311
During the summertime of 2007/2008, carbon dioxide (CO2) and methane (CH4) fluxes across air–water interface were investigated in the littoral zones of Lake Mochou and Lake Tuanjie, east Antarctica, using a static chamber technique. The mean fluxes of CO2 and CH4 were ?70.8 mgCO2 m?2 h?1 and 144.6 μgCH4 m?2 h?1, respectively, in the littoral zone of Lake Mochou; The mean fluxes were ?36.9 mgCO2 m?2 h?1 and 109.8 μgCH4 m?2 h?1, respectively, in the littoral zone of Lake Tuanjie. Their fluxes showed large temporal and spatial dynamics. The CO2 fluxes showed a significantly negative correlation with daily total radiation (DTR) and a weakly negative correlation with air temperature and water temperature, indicating that sunlight intensity controlled the magnitude of CO2 fluxes from the open lakes. The CH4 fluxes significantly correlated with local air temperature, water table and total dissolved solids (TDS), indicating that they were the predominant factors influencing CH4 fluxes. Summertime CO2 budgets in the littoral zones of Lake Mochou and Lake Tuanjie were estimated to be ?152.9 gCO2 m?2 and ?79.7 gCO2 m?2, respectively, and net CH4 emissions were estimated to be 312.3 mgCH4 m?2 and 237.2 mgCH4 m?2, respectively. Our results show that shallow, open, alga-rich lakes might be strong summertime CO2 absorbers and small CH4 emitters during the open water in coastal Antarctica. 相似文献
190.
Hong Sui Zhengtao Hua Xingang Li Hong Li Guozhong Wu 《Environmental science and pollution research international》2014,21(9):5774-5784
Petroleum ether was used to extract petroleum hydrocarbons from soils collected from six oil fields with different history of exploratory and contamination. It was capable of fast removing 76–94 % of the total petroleum hydrocarbons including 25 alkanes (C11–C35) and 16 US EPA priority polycyclic aromatic hydrocarbons from soils at room temperature. The partial least squares analysis indicated that the solvent extraction efficiencies were positively correlated with soil organic matter, cation exchange capacity, moisture, pH, and sand content of soils, while negative effects were observed in the properties reflecting the molecular size (e.g., molecular weight and number of carbon atoms) and hydrophobicity (e.g., water solubility, octanol–water partition coefficient, soil organic carbon partition coefficient) of hydrocarbons. The high concentration of weathered crude oil at the order of 105 mg kg?1 in this study was demonstrated adverse for solvent extraction by providing an obvious nonaqueous phase liquid phase for hydrocarbon sinking and increasing the sequestration of soluble hydrocarbons in the insoluble oil fractions during weathering. A full picture of the mass distribution and transport mechanism of petroleum contaminants in soils will ultimately require a variety of studies to gain insights into the dynamic interactions between environmental indicator hydrocarbons and their host oil matrix. 相似文献