Symphurus civitatium (Pleuronectiformes: Cynoglossidae), a second estuarine-occurring tonguefish off the Southeastern United States and Northern Gulf of Mexico

Two species of tonguefishes,Symphurus plagiusa (Linnaeus 1766) andSymphurus civitatium Ginsburg 1951, occur sympatrically and sometimes syntopically in shallow water habitats in North Carolina and Louisiana estuaries. In North Carolina, approximately 2% of 430 small (<75 mm SL) tonguefishes collected wereS. civitatium, while in Barataria Bay, Louisiana, this species was more abundant and cosmopolitan in distribution than wasS. plagiusa, comprising over 82% of 3,564 tonguefishes collected with a small beam trawl over a 2-yr period. Historical literature has regardedS. plagiusa as the only tonguefish species inhabiting inshore waters in both regions. Presence of a secondSymphurus species in shallow estuaries has been overlooked, most probably due to difficulties in identifying early post-settlement juveniles because both species have similar morphologies and overlapping dorsal-fin and anal-fin ray counts. Juveniles can be readily recognized by differences in number of caudal-fin rays (10 inS. plagiusa versus 12 inS. civitatium), especially when used in combination with pigmentation patterns and posterior extent of the jaws relative to the posterior margin of the lower eye. The most distinctive pigmentation difference between juveniles of these two species (allowing for accurate identifications of over 98% of juveniles) is the absence inS. civitatium (12–61 mm SL) of a series of melanophores overlying pterygiophore regions of the dorsal and anal fins on the blind side. This feature contrasts markedly with that of juvenileS. plagiusa (12–65 mm SL), which are characterized by two interrupted, diagonal series of dark chromatophores converging, but not merging, with posterior tapering of the body. Occurrence of two sympatric species of tonguefishes in estuarine environments in the northcentral Gulf of Mexico and southeastern U.S. potentially compromises results of earlier ecological and distributional studies that assumed presence of only a single tonguefish species in these regions.     

对西金大厦基坑降水工程的思考

西金大厦场地勘察工作于1994年8月完成,5年以后开始基坑降水工作。本文分析场地地下水现状,剖析降水设计方案,提出有针对性的降水新构想。     

山东省牟平邓格庄金矿Ⅱ号矿体深部预测

牟平邓格庄金矿为一富黄铁矿石英脉型金矿床,其Ⅱ号矿体金品位及其厚度数据处理表明矿体具有向北侧伏的规律.Ⅱ号矿体深部(-225~-345 m)地球化学原生晕研究表明,其原生晕呈反向分带.据上述研究推测Ⅱ号矿体-345 m以下地段还有盲矿体的存在.     

石油对金的活化迁移作用的研究初探

在测定原油中金浓度和对相关岩心样品中金分析的基础上，初步研究了原油对岩石中金的活化迁移作用。结果表明，原油中的金浓度与对应的岩心样品中含金量呈正相关性，原油对岩石中金具有较强的活化迁移作用，为原油对金的相互作用的研究提供了重要的实验基础。     

咸阳地热田水溶氦气资源评价与开发利用前景分析

近年来,在咸阳地热田资源开发利用过程中,发现地热水中普遍伴生有较高浓度的氦气(0.16％～3.00％).多年监测结果表明,伴生的氦气资源分布范围广,含量高且稳定,表现出了较大的资源潜力.通过对咸阳地热田水溶氦气资源量的定量计算,得到咸阳市区水溶氦气资源量为10.92×108 m3,可采量为0.22×108 m3.认为咸阳市开发利用水溶氦气资源的优势显著,在咸阳率先开展水溶氦气提取试验及建立年产万方级水溶氦气先导性试验区,可为在渭河盆地建立我国氦气工业基地及热、矿、水综合开发利用起到示范作用.     

InSAR技术在多年冻土区形变监测的应用

作为大地测量的一种新兴空间技术,合成孔径雷达干涉（synthetic aperture radar interferometry, InSAR）具有全天时、高精度、大范围和速度快的优点,逐渐被应用于多年冻土区地表形变监测中。通过综述多年冻土形变原理及InSAR监测多年冻土形变的应用实例,研究表明：在气候变暖的背景下,多年冻土区地表年际形变以下沉为主,多年冻土上限附近地下冰含量的大小是影响年际形变量的主要因素;活动层内土壤含水量影响着地表季节形变量的大小,不同类型多年冻土区的地表年际形变量和季节形变量存在着较大的差异。研究还表明,不同波长的SAR产品在不同类型多年冻土区的适用性不同,下垫面特征对利用InSAR获取地表形变量有较大影响,L波段的SAR数据在植被覆盖度较好的区域有更好的效果。由于InSAR的失相干问题,加之目前还缺少长时间、多类型、高频率的实测形变结果作为验证和标校数据,获取准确且连续的大范围形变数据较为困难。针对目前寒区研究需求,布设野外长期观测站点,建立适用于不同多年冻土区的地表形变反演算法,构建具有较高精度和较高时空分辨率的地表形变数据集具有重要的实践和科学意义。     

宜川—旬邑地区长6～长8储层流体包裹体特征及意义

宜川—旬邑地区显示油气丰富,但是实际勘探效果不佳,通过宜川-旬邑地区延长组长6~长8储层流体包裹体岩相、均一温度、盐度的研究表明,该区主要发育液烃包裹体和气液烃有机流体包裹体。流体包裹体主要分布在石英次生加大边与石英颗粒裂纹、方解石胶结物和裂缝充填物中;包裹体个体多为5~15μm,均一温度为49~127℃,平均89℃。80%以上样品的含油流体包裹体丰度(GOI)大于或等于1%,其中近40%样品的GOI在5%以上。流体包裹体总体偏向低盐度,包裹体盐度与均一温度间的相关性差。结合延长组成岩作用、热史和埋藏史分析指出,延长组发生过广泛的油气运移与充注事件,充注时间主要在早白垩世早期—早白垩世晚期;油藏具储层边致密、石油边成藏的特点,受后期构造运动的影响,原始封闭体系遭到破坏,在方解石胶结物不甚发育且原生粒间孔隙保存较好的区域,有望获得油气勘探的突破。     

心墙堆石坝应力状态对渗流场影响的有限元分析

一般对土石坝进行渗流分析时都未考虑坝体的应力场对渗流场的影响。然而,在土石坝的蓄水过程中,坝体内的应力状态复杂且变化大,对渗流场的影响也较大。因此,忽略应力场对渗流场的影响必然造成一定的误差。用有限元方法对心墙堆石坝体蓄水过程中考虑和不考虑应力场影响的渗流场进行对比分析,计算结果表明,渗流-应力耦合作用下坝体局部压密变形,渗透流速减小,心墙下游出逸区域的水力坡降峰值明显高于非耦合值。因此,渗流分析时有必要考虑应力场的影响,否则会得出偏于危险且对工程不利的结果     

多工况下汉源二蛮山滑坡机理数值模拟

利用FLAC3D软件对四川省雅安市汉源县二蛮山滑坡坡体进行建模,模拟降雨滑坡过程,并进行应力应变特征及稳定性计算分析,从而为深入研究地震及降雨诱发再次滑坡及防灾减灾提供可靠依据。研究中假设地震工况,对边坡进行详细的动力分析,得到了各监测点动力特征曲线;通过降雨工况下坡体稳定性系数分析得到了不同强度折减安全系数。研究结果表明,滑源区相对特殊的地形条件和地质构造以及不利的结构面组合是滑坡的基础;前期强降雨期间饱水加载以及大量雨水沿斜沟张裂结构面的下渗软化作用,是诱发滑坡发生的关键因素。      

Contact angles in CO2-water-coal systems at elevated pressures

Injection of carbon dioxide into coal seams is considered to be a potential method for its sequestration away from the atmosphere. However, water present in coals may retard injection: especially if carbon dioxide does not wet the coal as well as water. Thus contact angles in the coal-water-CO₂ system were measured using CO₂ bubbles in water/coal systems at 40 °C and pressures up to 15 MPa using five bituminous coals. At low pressures, in this CO₂/water/coal system, receding contact angles for the coals ranged between 80° to 100°; except for one coal that had both high ash yield and low rank, with a contact angle of 115°, indicating that it was hydrophilic. With increasing pressure, the receding contact angles for the different coals decreased, indicating that they became more CO₂-wetting. The relationship between contact angle and pressure was approximately linear. For low ash or high rank coals, at high pressure the contact angle was reduced to 30-50°, indicating the coals became strongly CO₂-wetting; that is CO₂ fluids will spontaneously penetrate these wet coals. In the case of the coal that was both high ash and hydrophilic, the contact angle did not drop to 90° even at the highest pressures used. These results suggest that CO₂ will not be efficiently adsorbed by all wet coals equally well, even at high pressure. It was found that at high pressures (> 2 MPa) the rate of penetration of carbon dioxide into the coals increased rapidly with decreasing contact angle, independently of pressure. Injecting CO₂ into wet coals that have both low rank and high ash will not trap CO₂ as well as injecting it into high rank or low ash coals.