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991.
992.
Zhi?LiEmail author Zhemin?Lü Jingjing?Li Xiaoping?Shi 《Theoretical and Applied Climatology》2017,127(1-2):103-110
Pediatric vehicular hyperthermia (PVH) persists as the leading cause of non-crash, vehicle-related deaths among US children with an average of 37 children dying after being left unattended in motor vehicles each year. Our study aims to demonstrate the microclimate conditions within an enclosed vehicle that lead infants and small children to reach key physiological heat thresholds: uncompensable heating (>37 °C) and heatstroke (>40 °C) under “worst case” conditions. A modified version of the Man-Environment Heat Exchange Model was used to compute the length of time for an infant to reach these thresholds. Several different scenarios were modeled using different initial cabin air temperatures. Assuming full sun exposure and maximum heating rates, an infant may reach uncompensable heating within 5 min and experience hyperthermia anywhere from 15 to 55 min depending on the starting cabin air temperature. The rapid approach of these heat-related thresholds occurs as enclosed vehicles maximize heating and minimize cooling mechanisms, leading to net heating and increase in core body temperatures. Health experts can use this information to support public health messaging on the topic of PVH by explaining why it is important to never leave a child alone in a car and increase the public perception of severity and susceptibility to this ongoing public health issue. 相似文献
993.
Guan Xiaoping 《中国地质大学学报(英文版)》1998,9(2):30
SinceHess(1964)foundforthefirsttimethediferenceof0.3km/sbetweenthevelocitiesoflongitudinal(P)wavesperpendiculartoandparalelto... 相似文献
994.
采用最小二乘法代替傅里叶系数计算公式来确定谐波系数,使用若干个磁静日的谐波系数均值作为磁扰日的谐波系数,再取一定截断阶数的傅里叶级数作为太阳静日变化模型。以此进行地磁观测数据中太阳静日变化和磁扰的分离。然后对日变站太阳静日变化进行地方时差校正得到测点处的太阳静日变化,将其与地磁扰动一起用于测点的日变改正。通过台站数据的计算结果分析了模型的截断阶数、日变站与测点间的经度差等因素对日变改正精度的影响,并对比了此方法与扰日法的改正效果。结果说明了此方法的合理性与可行性。 相似文献
995.
China's population has been aging rapidly in recent years, with more than 90 percent of elderly people living at home and many of them alone. Although they are in need of many services, healthy and affordable meals are particularly important because most find cooking three meals a day to be a challenge. In response, several cities in China such as Beijing, Shanghai, and Xi'an have set up Elderly Dining Services (EDS) with government subsidies. A survey of 227 local residents aged sixty and over as well as the nine designated restaurants for EDS in the area was conducted in 2012 in the Xinjiekou Jiedao community of Xicheng District in Beijing to determine whether these services are accessible and sufficient to meet the demand of the local elderly population. Our findings show that eat-in services are considered within an acceptable distance for 90 percent of elderly residents and that delivery services within 1,000 m would cover 100 percent of the 16,913 elderly residents in the area (although not all of them are interested in EDS). The potential demand far exceeds what the nine EDS restaurants are willing to provide, however. Our results indicate that the main issue in supply shortage is cost, especially for delivery services. 相似文献
996.
Detailed wind tunnel tests were carried out to establish the mean downwind velocity and transport rate of different-sized loose dry sand at different free-stream wind velocities and heights, as well as to investigate the vertical variation in the concentration of blowing sand in a cloud. Particle dynamic analyzer (PDA) technology was used to measure the vertical variation in mean downwind velocity of a sand cloud in a wind tunnel. The results reveal that within the near-surface layer, the decay of blown sand flux with height can be expressed using an exponential function. In general, the mean downwind velocity increases with height and free-stream wind velocity, but decreases with grain size. The vertical variation in mean downwind velocity can be expressed by a power function. The concentration profile of sand within the saltation layer, calculated according to its flux profile and mean downwind profile, can be expressed using the exponential function: cz=ae−bz, where cz is the blown sand concentration at height z, and a and bare parameters changing regularly with wind velocity and sand size. The concentration profiles are converted to rays of straight lines by plotting logarithmic concentration values against height. The slope of the straight lines, representing the relative decay rate of concentration with height, decreases with an increase in free-stream wind velocity and grain size, implying that more blown sand is transported to greater heights as grain size and wind speed increase. 相似文献
997.
利用东亚及邻区49个地磁台1970-1979年、H、Z的实测年均值,逐年计算、缓制了蒙古异常的地磁非偶极场等值图,给出了蒙古异常非偶极场Zn分量的焦点位置和强度变化及其对中国东北地区地磁场的影响量级,计算表明蒙古异常的年变化是该区地磁场年变化的主要成份。 相似文献
998.
999.
简要地阐述了桂阳县东塔景园建设项目滑坡的地质环境条件、现状成因。根据现场调查勘探,利用滑坡数学模型对滑坡进行了稳定性计算及评价,提出了该滑坡的相应防治对策。 相似文献
1000.