博尔塔拉河流域过去461 a夏季温度的重建和分析

 根据采自天山北坡西段博尔塔拉河流域树木年轮样本,建立了该流域的树木年轮年表序列。通过相关普查得出,该年表与夏季（7-8月）月平均温度存在明显的负相关关系,且具有明确的树木生理学意义。用然布尔萨依（t+2）,铁里门萨依（t+1）和阿合峡特（t+2）三个差值树轮年表可较好地重建该流域461 a来该时段的月平均温度,并通过交叉检验可知所构建的方程是稳定可靠的。通过分析发现,博尔塔拉河流域461 a来夏季月平均温度经历了27个偏暖阶段,存在11 a、12 a、13 a、22 a、27 a、40 a、72 a、93 a、94 a、95 a、146 a和147 a的周期变化； 461 a来博尔塔拉河流域夏季月平均温度序列在1696年、1838年、1842和1962年发生过气温突变。     

鄂尔多斯盆地西部晚三叠世构造属性探讨

有关鄂尔多斯盆地西部晚三叠世的构造属性问题,前人的观点大多认为该时期为(类)前陆盆地,笔者对此提出置疑,主要有3个方面的依据:首先,对西缘汝箕沟、石沟驿和崆峒山地区晚三叠世延长组的3套粗碎屑沉积进行了重新认识。汝箕沟延长组确实为边缘相沉积,但其附近层位板内玄武岩的出现,表明该区晚三叠世为拉张环境下的沉积。最新研究表明,石沟驿地区延长组沉积厚度并不大,不超过1500m。崆峒山砾岩沉积可能受西南部的秦祁造山带影响所致,不能作为盆地西部沉积的代表。其次,通过编制晚三叠世延长组地层等厚图及一系列东西向地层剖面对比,发现该时期以往认为的盆地西部从南至北的巨厚沉降带并不存在。最后,通过地震剖面、平衡剖面和裂变径迹测试数据分析,指出西部现今存在的横山堡后冲构造带和马家滩大型逆冲推覆构造带并未形成于晚三叠世,其最早形成于晚侏罗世。故鄂尔多斯盆地西部晚三叠世构造属性并非为前陆盆地,而是残延克拉通内叠合盆地的组成部分。该认识对盆地西部的油气勘探具有重要意义。     

Earthquake-induced residual deformation of Ariake clay deposits with leaching

It is widely known that the sensitivity ratio of Ariake marine clay increases, if the clay is leached. Therefore, it is assumed that the mechanical properties of such clay considerably change and the shear strength decreases, if it is subjected to a cyclic load as a disturbance force, like earthquakes. In the present study, dynamic deformation and strength tests, as well as consolidation tests were conducted on Ariake clay that had leached. Static shear tests were also carried out on the clay after it had been subjected to a cyclic load. The stability of man-made earth structures on Ariake clay deposits that had leached during earthquakes was investigated. Undisturbed samples of the clay sedimented in the sea area were used in all the tests. Furthermore, an earthquake-induced residual deformation analysis was also conducted on the basis of the test results described above. Consequently, the following behaviors were observed in the study. (1) When Ariake marine clay was leached, the dynamic strength decreased and the shear modulus after subjecting it to a cyclic load remarkably decreased. (2) The effect of the leaching on the behavior of Ariake clay deposits was considerable during earthquakes.     

Preparation and evaluation of polyaluminum chloride sulfate (PACS) as a coagulant to remove natural organic matter from water

A series of polyaluminum chloride sulfate (PACS) coagulants, which have different SO₄^2–/Al³⁺ and OH/Al (γ) mole ratio, has been successfully developed using AlCl₃·6H₂O, Al₂(SO₄)₃·18H₂O and Na₂CO₃ as raw materials. The coagulation performance of PACS for removing natural organic matter (NOM) from surface water was evaluated, and the effect of SO₄^2–/Al³⁺ mole ratio and γ value in coagulants PACS on DOC and UV₂₅₄ removal was determined. Furthermore, the influence of pH and dosage of the selected PACS with a SO₄^2–/Al³⁺ ratio of 0.0664 and a γ value of 2.0, which achieved the best coagulation performance for the removal of DOC and UV₂₅₄ of all PACS coagulants, on the removal of DOC and UV₂₅₄ and residual aluminum concentration in treated water was investigated. The results were compared with the ones of polyaluminum chloride (PAC) with γ value of 2.0. The experimental data show that the performance of PACS as a coagulant was highly dependent on SO₄^2–/Al³⁺ mole ratio and γ value. Both for the selected PACS and for PAC, the best DOC and UV₂₅₄ removal results were obtained in the range of pH from 5.0 to 8.2 and at the coagulation dose of 5.0 mg/L as Al. Under the optimum coagulation conditions, the selected PACS gave higher DOC and UV₂₅₄ removal efficiencies, and lower residual aluminum concentrations in the treated water than PAC. The maximum removal of DOC and UV₂₅₄ for PACS was approximately 88.0% and 93.0%, respectively. At the optimum coagulant dose and pH 6.5, the concentration of residual aluminum in treated water by both selected PACS and PAC can comply with the regulated limits. The major mechanisms of NOM removal by PACS and PAC coagulation involve complexation‐charge‐neutralization‐precipitation.     

考虑强度退化效应的堤坝抗震稳定性评价方法

考虑土的动强度随振动孔隙压力上升的衰减效应,将拟静力极限平衡分析和滑动体位移分析相结合,提出了堤坝抗震稳定性评价方法.首先,基于土工动力有限元分析,确定坝坡潜在滑动土体的平均加速度时程,进而,基于拟静力概念,采用极限平衡分析,确定坝坡的安全系数随时间的变化历程,其中当安全系数瞬时小于1时,表明坝坡在地震中处于瞬时超载状态,采用Newmark刚体滑块模型估算瞬时超载所产生的滑动位移,将各个超载阶段的滑动位移叠加,求得设计地震动作用下堤坝边坡的累积滑移量,根据这种方法所进行的数值计算与分析表明,考虑强度循环退化效应后所得到的坝坡滑移量更为合理.     

储层微观动态地质作用与剩余油研究——以胜利油区胜坨油田沙二段为例

长期注水开发油田的开发流体，长期对储集层进行浸泡、驱动，使储集层的众多微观孔隙与喉道的极其微小空间发生风化、剥蚀、溶解和沉积等微观动态地质作用。这些地质作用是由于开发流体打破了地下的动态平衡产生的，它对储集层的岩石骨架、孔隙和喉道等进行改造和破坏，进而控制剩余油的形成与分布，并使得微观剩余油存在多种分布模式。研究指出微观动态地质作用是储集层随开发而发生变化的重要原因，是控制剩余油形成和分布的基本因素。微观动态地质作用长期持续存在，并对储集层进行改造和破坏，使得储集层中的剩余油分布更复杂。     

High Resolution, Deep-Tow Seismic Survey to Investigate the Methane Hydrate Stability Zone in the Nankai Trough

Abstract. A high frequency deep-tow seismic survey was carried out in the Nankai Trough area in 1996. The objective of the survey was to obtain high resolution seismic sections and velocity profiles of the methane hydrate zone, inferred from the strong BSR events seen on conventional seismic data in the area. A special feature of the survey is that both the source and the streamer cable are towed close to the seabed. This special acquisition geometry requires special data processing to handle the varying source and receiver depths. A CMP floating datum processing sequence was designed which led to high quality sections of the shallow geology. A key step in the processing was devising a residual statics technique to compensate for errors in the measured depths.
The processing sequence was applied to a number of lines, totaling 200 km. The final data quality was highly variable. Some lines produced high quality sections and others, much poorer sections with few interpretable events. Conventional seismic data in the area also shows variation in the data quality so part of the reason is a variation in the sub-sea geology, but the deep-tow data is much more sensitive to change in conditions than conventional data. With the current acquired data and processing sequence the deep-tow system offers most advantages when 1) the water depth is around 1 km or greater, 2) the seabed and underlying geology is not too complex, and 3) the acquisition proceeds smoothly with regular shotpoints, slowly varying depths, and with accurate positioning.     

滑带土强度参数的估算方法

滑带土强度参数的确定是滑坡稳定必分析及防治工作设计的关键参数,文中在滑带土强度的影响因素研究基础上,讨论了多种强度参数的评估方法,实际应用时,采用科学合理的反算法及综合多种方法评估滑带土的强度参数被证明是有效的途径。     

Algal genetic engineering in China: Progress and cooperation

INTRODUCTIONTheWellknownthooriesofPritChard(l952)andHansenandRattray(l965)destribeestUarine~ationasfashenedseawatCrflowingoutinanearsurfacelayerandanwaterflowinlandwardbeow.WhenthelateralvariationofbathyInetryistakenintoarmunt,theverticalshatificationrnaybereplatal,orpadiallyreplaed,byalateralstIatfficatfonalongwithalateralvariatinnofveodtyfiekl,whichrnayshowalandwardflowofsaltwaterinthedeepchannelandanWhrdflowoffasherWhterontheshoaIs.fumodeofbarotaedationWhsfustsuggestalbyFischer(l9…     

On the Structural Link Between Variables in Kriging with External Drift

Kriging with external drift allows one to estimate a target variable, accounting for a densely sampled auxiliary variable. Contrary to cokriging, kriging with external drift does not make explicit the structural link between target variable and auxiliary variable, for the latter is considered to be deterministic. In this paper, we show that kriging with external drift assumes implicitly an absence of spatial dependence between the auxiliary variable and the residual of the linear regression of target variable on auxiliary variable at same point. This is the simple model with orthogonal residual, where cokriging is collocated and coincides with kriging of the residual. In this model, the cross-structure is proportional to the structure of the auxiliary variable, and the linear regression of target variable on auxiliary variable does not depend on the support.