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581.
兰莎 《福建地质》2011,30(1):55-61
宁德地质公园集晶洞花岗岩地貌、火山岩地貌、河床侵蚀地貌、海岸海蚀地貌于一体,景观具有很高的观赏价值.公园的许多地质遗迹具有稀有性和独特性,多种地貌景观的组合,反映了其地质历史的复杂性.地质遗迹与生物、人文景观的结合使宁德地质公园具有丰富的科学内涵和科普价值.  相似文献   
582.
Ammonium molybdate has been used to remove the toxic metals in waste water by forming precipitates, such as Pb. However, the ammonium molybdate has not been used to remediate the toxic metals contaminated soils. The objectives of this study were to report: (1) the reaction mechanisms of ammonium molybdate with toxic metals; (2) the effects of ammonium molybdate on (im)mobilization of the toxic metals in soils; (3) and the effects of ammonium molybdate on uptake toxic metals from soils by alfalfa (Medicago sativa L.) plants. In this paper, it was found that: the effects of ammonium molybdate on toxic metals are amphoteric-immobilization/mobilization. Cr and Zn can be precipitated with ammonium molybdate, but Cd, Ni, Cu can be formed more soluble fractions with ammonium molybdate. The ammonium molybdate can be named as half-chemical stabilization agent, half-extracting agent, or amphoteric agent. The contents and BCF values of toxic metals in alfalfa plants were increased after the soils were treated with ammonium molybdate. TF values of alfalfa plants (both controls and treatments) were lower than 1. The addition of ammonium molybdate can increase the acid soluble fractions of Cd, Ni, Cu, and residual fractions of Cr, Zn. In other words, the toxicities of Cd, Ni, and Cu to plants in soils have been increasing. Instead, the toxicities of Cr, Zn have been decreasing. The ammonium molybdate has promoted plants to produce more biomass, but the growths of shoot and root in seedling stages have been decreased by the increasing Cd, Ni, and Cu toxicities which caused by ammonium molybdate.  相似文献   
583.
按照大气动力学和热力学的原理,采用划分天气型、定性判别和定量计算相结合,预报与服务系列化,在微机上研制出6-9月湿球温度短期客观预报服务系统,湿球预报的开展,为纺织,仓贮等行业空调工艺超前决策提供重要依据。  相似文献   
584.
TS—2A系留探空系统的对比实验   总被引:1,自引:0,他引:1  
张文煜  陈长和 《高原气象》1992,11(3):330-334
  相似文献   
585.
暴雨降水强度和历时的面积分布律   总被引:1,自引:2,他引:1  
马力  沙拉买提 《高原气象》1993,12(4):432-436
暴雨的历时,面积和深度的关系(时、面,深)是水文气象学的重要研究课题之一。近年来,从熵最大原理的角度曾推导出其中的两个负指数关系,并被大量的观测所证实。本文通过对5个个例的分析发现,降水过程的另外两组变量也服从负指数关系。即不同的降水历时与其占有的面积之间和不同的降水强度与其占有的面积之间都遵从负指数关系。而这两组新关系显然对暴雨预告有实用价值。  相似文献   
586.
The transports of dust are calculated using 3-dimensional(3-D) trajectory method for three cases of duststorms in the terrain-following coordinate system,and the synoptic processes are also discussed for each case.The case of 17-20 April 1980,a severe duststorm was associated with the rapid development of a cyclone over the Mongolia Plateau.The dust moved from west to east across several deserts,formed a typical dust path in spring.The other two were weaker and the dust was triggered by the strong wind behind the cold front from northwest or north.Because the vertical velocity is considered in 3-D trajectory analysis,trajectories calculated should better reveal the transport rule of the dust particles and the results seem to be more consistent with the synoptic processes.The trajectory analysis on the 2-D isobaric surfaces is simpler but can be used only in the conditions with weak vertical wind shear and weak vertical velocity.The difference of trajectories at lower levels between two methods may be caused by the different treatment of orography.  相似文献   
587.
通过移动走航式观测获取长沙市岳麓山周边道路不同通勤时段PM2.5浓度数据,结合土地覆盖、兴趣点、数字高程模型、邻近污染源和街区路网分布5类微环境地理因子,采用空间聚合、空间自相关分析、分位数回归分析等方法,探究研究区内道路PM2.5浓度的时空变化及其与城市微环境地理因子的潜在联系.结果表明,长沙市岳麓山周边道路不同通勤时段PM2.5浓度时空差异明显:晚高峰时段PM2.5中位数浓度高达31.5μg/m3,早高峰和非高峰时段分别为28.2μg/m3和22.0μg/m3;高值PM2.5浓度在通勤高峰时段空间分布相对集中,在非高峰时段则相对分散.就地理因子影响而言:不同通勤时段影响PM2.5浓度的微环境地理因子在数量与类别上存在差异;同时,微环境地理因子对不同分位数道路PM2.5浓度的影响也具有异质性.依据各通勤时段不同地理因子的影响趋势和影响程度,采取相应的针对性调控、空间合理配置等干预策略有望全面降低道路PM2.5浓度.本研究可为基于空气质量视角的城市空间规划与开发建设调控提供科学依据.  相似文献   
588.
Health inequality is an increasing concern worldwide. Using the coefficient of variation, Theil index, exploratory spatial data analysis, and spatial panel econometric model, we examined the regional inequality, spatio-temporal dynamic patterns, and key factors in the health status of Chinese residents from 2003 to 2013. We found that China’s residential health index (RHI) decreased from 0.404 to 0.295 in 2003–2013 at an annual rate of 2.698%. Spatially, resident health status, based on the RHI, has improved faster in the western region than in the eastern and central regions. Inequality in resident health status continued to increase between 2003 and 2013; inequality between regions decreased, but health status inequality expanded within regions. Furthermore, disparities in health status grew faster in western regions than in the eastern and central regions. The spatial distribution of resident health status formed a “T-shaped” pattern across China, decreasing from east to center then to the west with a symmetric decrease north and south. Using the change in Moran’s I from 2003 to 2008 and 2013, we found that the distribution of resident health status across China has narrowed. All the hot spots and cold spots have decreased, but they are also stable. Resident health status formed a stable cold spot in the western regions, while the east coastal area formed a stable hot spot. Selected explanatory variables have significant direct impacts on resident health status in China: increasing per capita GDP, per capita spending on health, and urbanization, and improving environmental quality all lead to better resident health status. Finally, we highlight the need for additional research on regional inequality of resident health status across multiple time, spatial, and factor domains.  相似文献   
589.
The characteristics of tropical cyclone(TC) extreme rainfall events over Hainan Island from 1969 to 2014 are analyzed from the viewpoint of the TC maximum daily rainfall(TMDR) using daily station precipitation data from the Meteorological Information Center of the China Meteorological Administration, TC best-track data from the Shanghai Typhoon Institute,and NCEP/NCAR reanalysis data. The frequencies of the TMDR reaching 50, 100 and 250 mm show a decreasing trend[-0.7(10 yr)~(-1)], a weak decreasing trend [-0.2(10 yr)~(-1)] and a weak increasing trend [0.1(10 yr)~(-1)], respectively. For seasonal variations, the TMDR of all intensity grades mainly occurs from July to October, with the frequencies of TMDR 50 mm and 100 mm peaking in September and the frequency of TMDR 250 mm [TC extreme rainstorm(TCER) events]peaking in August and September. The western region(Changjiang) of the Island is always the rainfall center, independent of the intensity or frequencies of different intensity grades. The causes of TCERs are also explored and the results show that topography plays a key role in the characteristics of the rainfall events. TCERs are easily induced on the windward slopes of Wuzhi Mountain, with the coordination of TC tracks and TC wind structure. A slower speed of movement, a stronger TC intensity and a farther westward track are all conducive to extreme rainfall events. A weaker northwestern Pacific subtropical high is likely to make the 500-h Pa steering flow weaker and results in slower TC movement, whereas a stronger South China Sea summer monsoon can carry a higher moisture flux. These two environmental factors are both favorable for TCERs.  相似文献   
590.
诸多沉积记录揭示,中国北方早期历史,气候环境大致经历了3580-3050 cal a BP、3050-1800 cal a BP两个阶段;前者为稳定的湿润气候期,后者为逐渐趋于干燥的气候期;前期为中国历史上第二个王朝—商王朝统治期,政局稳定,社会承平,王朝较为稳定地传承了500余年,是中国历史上“寿命”最长的朝代;后者对应西周—东周(春秋—战国)—秦—西汉—东汉—三国等朝代,在不足1300年内,政权格局多次更迭,表现出一种与前期截然相反的社会政治生态。这期间,以都城为标志的王朝的重心,具有向东南迁移的趋势。年代对比发现,商代夏、周代商、平王东迁、西汉甚至东汉灭亡等改朝换代的社会政治事件,都与沉积记录所指示的气候环境的显著变化(恶化)对应。研究再次证实早期的中国历史与气候变化存在密切的关系,并认为如下两个因素可以阐述这种关系的存在:① 中国北方地理环境空间是扇状的,且自然环境具有梯度变化的特征,这种地理环境格局叠加在气候变化之上,具有特殊的加剧与舒缓区域社会矛盾的作用。② 小农经济具有对气候变化的特殊敏感性。对西汉所做的案例考察认为,不尽合理的社会体制往往通过一系列反馈作用将这种敏感性在气候恶化阶段“放大”,随之形成一系列连锁反应,由此造成的各种危机成为王朝崩溃重要因素。  相似文献   
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