Spatial-temporal Variations of H2 Concentration in Soil Gas in the Seismic Fault Zone Produced by the Wenchuan MS 8.0 Earthquake

Degassing of Hydrogen (H₂) from fault may be a good indicator of fault activity. The concentration of H₂ in soil gas in the seismic surface rupture zone produced by the Wenchuan M_S 8.0 earthquake was investigated in twenty three measuring regions in order to explore the relationship between the spatio-temporal variations of H₂ concentration in soil gas along the seismic rupture zone and the vertical displacements and aftershocks activities. The results indicated: ① the sources of H₂ were directly related to from the release of natural gas reservoirs; ②the average concentration of H₂ in soil gas spatially decreased from Yingxiu to Nanba; ③the magnitudes of the H₂ concentration anomalies declined significantly with time. It is very significant to study the variation tendency of atmospheric environment with further research of degassing of H₂ from faults.     

准噶尔盆地中央坳陷莫索湾地区侏罗系三工河组深层致密砂岩气储集层特征及成因*

综合利用岩心、薄片、扫描电镜以及测井资料,对准噶尔盆地中央坳陷莫索湾地区侏罗系三工河组一段致密砂岩气储集层特征及致密化成因进行研究。结果表明: (1)三工河组一段储集层平均埋深超过4500 m,具低—特低孔、低—特低渗特征,属于典型深层致密砂岩气储集层;(2)沉积类型为浅水三角洲—湖泊相沉积,三角洲前缘水下分流河道砂岩为主要储集层;(3)岩石类型以细砂岩、粉—细砂岩为主,主要为低成分成熟度的岩屑砂岩,具有岩屑和塑性岩屑含量高及胶结物含量低的“两高一低”特征;(4)储集层孔隙类型以混合孔为主,孔隙-孔喉组合类型以中细孔-细喉型为主,孔喉分选性、连通性和渗流能力相对较差,微观孔隙结构总体较差;物质成分、压实作用及胶结物充填是3个导致储集层致密化的因素,从而形成三工河组一段深层致密砂岩气储集层。     

阵列式探地雷达信号极化场特征

阵列式观测是探地雷达系统研制和新型探测方法的一个重要发展趋势,而同形多源并发地下目标响应特征分析成为系统研制和数据处理研究的基础和前提。阵列式天线的多源并发信号及目标反射信号存在复杂的极化特性,但同时也包含更多目标特征的响应信息。本文针对基于似平面波探地雷达系统,分析了目标体在极化平面波照射下的响应特征,从多极化信号角度分析典型地下目标体形态特征;并采用时域有限差分正演分析方法,通过对阵列天线接收到的数据沿时间轴进行积分来获得目标在地表投影的分布情况,分析了一维及二维分布的收发天线阵列对目标的检测。研究成果表明,多极化综合特征分析能够有效改善目标检测的稳定性,提高目标响应信号的信噪比,减弱天线方向图和目标散射截面闪烁对数据剖面的影响,降低数据处理和解释的难度。     

Effects of waterlogging and cadmium on ecophysiological responses and metal bio-accumulation in Bermuda grass (<Emphasis Type="Italic">Cynodon dactylon</Emphasis>)

Bermuda grass (Cynodon dactylon) can endure long-term and deep submergence stress and cadmium toxicity, respectively. But we do not know whether they can endure cadmium plus waterlogging and what are the differences of ecophysiological responses and metal bio-accumulation of Bermuda grass subjected to normal condition, waterlogging, cadmium or cadmium-and-waterlogging treatments, respectively. Here, the four treatments on Bermuda grass are performed with four replications. Our objective is to determine the ecophysiological responses and endurance abilities, cadmium and zinc bio-concentration and translocation, and the metal uptake mechanisms of Bermuda grass subjected to the four treatments. Our results demonstrated different treatments showed different ecophysiological responses in Bermuda grass. The shoot weights of cadmium treatment were significantly lower than those of the other treatments when the values determined after treated 25 d. Cadmium had a certain promotion effect on the root growth at the early growth stage. SPAD values indicate the relative amounts of chlorophyll present in plant leaves. SPAD value of 35 d was higher than 25 d of cadmium treatment, indicating cadmium had negative effects on chlorophyll contents in the early stage, but the negative effects might be ameliorated as plants adapted to cadmium stress. Waterlogging induced the biomass decrease and accelerated cadmium translocation. The plant leaves had the highest cadmium contents exposed to cadmium-and-waterlogging treatment, while the root showed the highest cadmium contents suffered only cadmium stress. The bio-concentration factor of cadmium-and-waterlogging treatment was less than that of cadmium treatment, but the translocation factor of cadmium-and-waterlogging treatment was much greater than that of cadmium treatment, which indicated phytostabilization was the main phytoremediation process subjected to only cadmium stress, while phytoextraction was the main process when exposed to cadmium-and-waterlogging treatment. Bermuda grass was a cadmium hyperaccumulator and had strong adaptability to waterlogging, cadmium toxicity or both.     

Origin of the volcanic rocks erupted in the eastern Manus Basin: Basaltic andesite-andesite-dacite associations

There has been much recent interest in the origin of intermediate lava and several hypotheses are: 1) direct melting of the mantle under water-saturated conditions, 2) partial melting of altered crust, 3) fractional crystallization of parent magma, and 4) magma mixing of mafic magmas with dacitic/rhyolitic magmas. Volcanic rocks series ranging from basaltic andesite to dacite (SiO₂ ranges from 53.8 to 63.0 wt.%) from the eastern Manus Basin were detected for major and trace element compositions to understand their origin. Low H₂O contents, positive correlations of La-SiO₂ and Yb-SiO₂, oxygen isotope data and the indistinct change of trace element concentrations in oscillatory zoning of plagioclase phenocrysts rule out the models in which silicic lava results from direct melting of hydrous mantle, partial melting of altered oceanic crust or gabbros, and magma mixing, respectively. Besides, the geochemical data of whole rock and melt inclusions indicate that fractional crystallization plays a dominant role in generating the intermediate lava with subduction features.     

《湖北省地图集》制作难点及解决方法探析

以湖北省地图集编制为例,简要介绍了纪录湖北发展状况的大型综合性图集的表示内容,着重探讨了图集中各区域普通地图设计技术难点及新方法的应用,并分析了制作过程中出现的等高线综合、地貌晕渲、影像色调处理等问题及其解决方法。     

Expansion strategies and evolution paths of hotel groups in China

The organizational structure change of enterprises should be subject to the change of strategy, and strategy change is the reaction to the environment change. This paper studied the expansion strategies and evolution paths of hotel groups in China by a survey in 2007, in which the research objects were 91 hotel groups listed by China Tourist Hotels Association. The conclusions are drawn: based on the two dimensions of unification management function scope and the unification management degree, hotel groups can be divided into four strategic types, including strategically concentrated group, close function group, widespread alliance group and loose union group. Simultaneously there are three different expansion paths: stability path, growth path and undulation path. About 72.5% of Chinese hotel groups have a stability or growth expansion path.     

Mesoscale structure of the central South China Sea detected by SCSMEX Buoy and Argo float

We addressed the mesoscale structure variation of the central South China Sea (SCS) with the measurements by a long-lived Argo float and a high-resolution ATLAS buoy during 1998–2002. T-S diagram indicates cooling and freshening events in 2000 and 2001 with lower salinity (0.5–0.8) and lower temperature (1–1.7°C). Significant decrease in the net heat flux and increase in the precipitation suggest that the cooling and freshening is due to extra forcing by the atmosphere. Additional to large year-to-year changes, intraseasonal variability is moderate in the research area. The axis of the maximum intraseasonal temperature and salinity signals are mainly located on the thermocline. Typically, amplitude and period of intraseasonal temperature is about 2°C and 40–60 days, and that of salinity is 0.3–0.5 and 35–60 days. Rapidly-changing winds, heat flux, and precipitation are critical in controlling the intraseasonal fluctuations of the mixed layer of the area. Studies on heat and freshwater balance in the mixed-layer further suggest that horizontal advection plays an important role in intraseasonal fluctuation in the upper ocean. In addition, the energetic mesoscale propagation radiated from the east boundary is linked to the intraseasonal variability in winter.     

234Th-derived particulate organic carbon export flux in the western Arctic Ocean

To evaluate the particle dynamics and estimate the POC (particulate organic carbon) export flux from the euphotic zone in the western Arctic Ocean, ²³⁴Th-²³⁸U disequilibrium was applied during the second Chinese National Arctic Research Expedition (July 15–September 26, 2003). The POC export fluxes are estimated from the measured profiles of the ²³⁴Th/²³⁸U activity ratios and the POC/PTh ratios. The average residence times of the particulate and dissolved ²³⁴Th in the euphotic zone are 33 d and 121 d, and their average export fluxes are 480 dpm/m²d and 760 dpm/m²d, respectively. The scavenging and removal processes of particle reactive elements are active in the upper layer of the Chukchi Sea. The average residence time of ²³⁴Th increases from shelf to basin, while the export fluxes of ²³⁴Th decrease. The estimated POC export fluxes from the euphotic zone vary from 2.1 to 20.3 mmol/m²d, indicating that the western Arctic Ocean is an important carbon sink in summer due to efficient biological pump.     

基于不同地形的GPS对流层延迟插值方法研究

通过利用北京、武汉两地的GPS数据,采用反距离加权法、克里金法研究不同地形下GPS对流层延迟插值效果.经比较,反距离加权法与克里金法的插值效果基本一致,在对武汉地区进行GPS对流层延迟插值时插值效果均在毫米级,在北京地区的插值效果则有不同:平坦地区插值效果达到毫米级;山区插值效果为厘米级,无法满足应用需求.