1971—2010年三江源地区水汽输送变化分析

在利用三江源地区及邻近区域探空资料对NCEP/NCAR I再分析资料进行适用性分析的基础上,采用1971—2010年再分析资料的逐日风场和比湿数据,分析三江源地区水汽输送的变化。结果表明:1971—2010年,经向流入三江源地区的水汽显著减少,使区域总水汽收支也呈显著减少趋势。水汽通量在1970年代和1980年代的变化相对较小,在1990年代和2000年代的变化幅度则较大。三江源地区总水汽收支在春季、夏季和秋季均呈明显减少趋势,冬季则无明显变化。三江源地区水汽输入明显减少,特别是6月和9月显著减少,对该地区降水形成不利。     

湖南省三级天气预报会商辅助系统的设计与实现

针对天气预报会商业务,基于VB、Fortran90、Perl、C#、Bash shell综合编程技术和Curl、NCL、Surfer外部程序包,设计和开发了湖南省三级天气预报会商辅助系统,从技术上实现了天气预报会商气象信息产品的优化,和湖南各级会商发言PPT制作与传输的快速化、自动化;为增强湖南天气预报技术、思路交流,和提高全省各级天气会商质量和预报质量,提供了有效的业务技术支持。     

Holocene lake level variations on the Qinghai-Tibetan Plateau

Paleoshorelines indicative of multiple high lake stages can be found around many lakes on the Qinghai-Tibetan Plateau (QTP). Conspicuous paleoshorelines associated with the most recent highstands can be readily observed on satellite images and during field investigations. However, earlier paleoshorelines have been identified at only a few sites around these lakes due to a lack of clear shoreline features and limited spatial extension of those that can be identified. We investigated past lake highstands using published chronologies, Aster-DEM, Google Earth, and ArcGIS 9.2 software. These data suggest that (1) paleoshorelines of the most recent lake highstand were formed during the Holocene; (2) during this highstand, lake levels reached more than 90, 60–90, and 30–60 m higher than present in the central Gangdise and western Qiangtang areas, while in the eastern Qiangtang, Holxil-Yushu, and northeastern QTP areas highstands did not exceed 30 m above modern; (3) during the early Holocene, some lakes on the southwestern QTP combined to form large lakes, while lakes in the inland areas of the QTP were only a little larger during the Holocene high lake level stages.     

Comparison of metal(loid) concentrations in water, sediments and fish from two large shallow lakes

Hulun Lake and Taihu Lake are both large shallow lakes in China. In summer and winter of 2009, water, sediments and fish samples were collected from the two lakes and the concentrations of metal(loids) were analyzed. The results demonstrated that aqueous concentrations of arsenic (As), chromium (Cr), cadmium (Cd), nickel (Ni) and copper (Cu) in Hulun Lake were significantly higher than those in Taihu Lake. Especially, the As concentrations (about 130 μg/L) in Hulun Lake dramatically exceeded the permissible level of drinking water. Compared with Taihu Lake, metal(loid) concentrations in the sediments of Hulun Lake were significantly lower, which might have less impacts on the metal exchanges between water and sediments. In contrast, concentrations of the measured metal(loids) (including As) in fish from Hulun Lake and Taihu Lake were comparable, suggesting that the dramatic difference in aqueous and sediment metal(loid) concentrations had less influence on the metal(loid) bioavailability. The higher concentrations of dissolved organic carbon (DOC) and cations (e.g., Na⁺, K⁺ and Mg²⁺) in lake water might contribute to the reduced metal(loid) bioavailability to fish in Hulun Lake.     

Sorption of heavy metals from aqueous solution by dehydrated powders of aquatic plants

Ruppia maritima and Echinodorus amazonicus were prepared in a dehydrated powder form. The characteristics and mechanisms of adsorption of heavy metals were studied under various pH values, reaction times, and heavy metal ion concentrations. The results showed that under different pH and reaction time conditions, heavy metal adsorption was lead > cadmium > zinc > copper. The adsorption of lead increased linearly with the lead concentration. For cadmium, zinc and copper, the adsorption was saturated when metal ion concentration exceeded 200 mg/L. When a Freundlich model was applied, R ² values for the heavy metal adsorption by the aquatic plants mostly exceeded 0.9. The adsorption of heavy metal ions by these two aquatic plant powders was better explained by the Lagergren second-order equation than the first-order equation. From the Fourier Transform Infrared spectra, there was an adsorption peak at 2,115 cm^?1 for R. maritima. The peak shape did not change with metal affiliation except there was a shift of peak wavelength before adsorption. The results indicate that the mechanism of heavy metal adsorption by the two species is not simply on the mono-molecular layer level, and that intra-particulate dispersal is the dominant process. Heavy metal pollution does not affect the basic chemical components, and major substances involved in heavy metal adsorption including carbohydrates, cell wall pectin, and protein functional groups.     

Statistical analysis of the temporal stability of soil moisture in three desert regions of northwestern China

Soil moisture and its variations are key factors for understanding hydrological processes, which are characterized by a high temporal variability at different scales. The study was conducted at three field stations in the desert regions of northwestern China, where soil moisture measurements with gravimetric method were used to characterize the temporal stability of soil moisture using various statistical parameters and an index of temporal stability (ITS). The soils are a gray–brown desert soil at the Linze station, an aeolian sandy soil at the Fukang station, and a brown desert soil at the Cele station. Soil textures are accordingly sandy loam at Linze and Cele, and loamy sand at Fukang. The dynamic variation in soil moisture depends strongly on the rainfall pattern (amount and frequency) in these desert ecosystems. Soil moisture content is low and significantly different among the three desert ecosystems, with the maximum at the Linze station (6.61 ± 2.08 %), followed by the Cele (4.83 ± 0.81 %) and Fukang (3.46 ± 0.47 %) stations. The temporal pattern exhibits high variability because soil moisture is characterized by low temporal stability and a high coefficient of variation (CV). The standard deviation, CV, and ITS increase significantly with increasing soil moisture. Soil moisture displays a skewed frequency distribution that follows a logarithmic function at lower soil moisture but a log-normal distribution at higher values.     

火焰原子吸收法测定和计算误差的减小

通过对火焰原子吸收法样品分析误差产生的各主要环节的分析和实验的验证 ,指出在盐湖资源开发过程产生的混合样品分析中 ,样品稀释倍数、光谱干扰、电离干扰和计算方法是影响结果准确性的主要因素 ,进一步提出了减小误差的办法 ,并给出了用Excel处理数据的示例表格和相应的VBA程序代码。     

Windows终端在地震监测网络中的解决方案

地震监测是一项对震情应急反映要快 ,系统网络安全性要求较高的工作 ,Windows终端就是建立在系统网络的基础上 ,以允许多个用户同时登录到一台服务器并运行服务器上应用的网络系统终端。它具有成本低 ,安全性好 ,解决网络阻塞能力强 ,应急反映速度快等优势。“Windows终端”的局域网模式是目前应用较为广泛 ,使用性能较好的一种网络连接方式。本文系作者在参加福建省地震局“1 0 5 - 0 3”十五重点项目中 ,对监测中心的台网监测网络系统建设的思考。目前我局新办公楼即将竣工 ,我监测中心新的办公写字间网络系统连接方式 ,选择“Windows终端”不失为一个较好的方案。     

Multiwavelength Doppler factors for Fermi-detected gamma-ray loud blazars

We collect a sample of 51 Fermi-detected gamma-ray loud blazars with known radio Doppler factors and study properties of the Doppler factors of blazars at optical,X-ray and gamma-ray bands.A basic assumption is that the emission from the radio to gamma-ray bands of the blazars are produced by the nonthermal radiation of accelerated particles in a jet.Our results show that (1) the Doppler factors of blazars are a function of frequency,with the Doppler factor decreasing with frequency from the radio to X-ray ...     

Quasi-plane-hypothesis of strain coordination for RC beams seismically strengthened with externally-bonded or near-surface mounted fiber reinforced plastic

The application of fiber reinforced plastic(FRP),including carbon FRP and glass FRP,for structural repair and strengthening has grown due to their numerous advantages over conventional materials such as externally bonded reinforcement(EBR) and near-surface mounted(NSM) strengthening techniques.This paper summarizes the results from 21 reinforced concrete beams strengthened with different methods,including externally-bonded and near-surface mounted FRP,to study the strain coordination of the FRP and steel rebar of the RC beam.Since there is relative slipping between the RC beam and the FRP,the strain of the FRP and steel rebar of the RC beam satisfy the quasi-plane-hypothesis;that is,the strain of the longitudinal fiber that parallels the neutral axis of the plated beam within the scope of the effective height(h 0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis.The strain of the FRP and steel rebar satisfies the equation:ε FRP =βε steel,and the value of β is equal to 1.1-1.3 according to the test results.