Characteristics and evolution of lacustrine turbidite of Chang-7 Member of Yanchang Formation in northern Shaanxi

Lacustrine turbidite of Chang-7 Member in the studied area consists of sihstone and fine sandstone with respect to grain size, which is feldspathic lithie sandstone, syrosem arkose and arkose with respect to mineral constitution affected by provenance. There are such apparent signatures as lithology, sedimentary structure, sedimentary sequence and well logs, to recognize turbidite. During the paleogeographic evolution of Chang-7 Member, lake basin and deep lake are both at their maximum extent during Chang-73 stage, resulting in the deposition of Zhangjiatan shale with widespread extent and of turbidite with fragmental-like. Deep lake line is gradually moving toward lake center and turbidite sand bodies are gradually turning better with better lateral continuity, connectivity and more thickness, from stages of Chang-73, Chang-72 and Chang-7t, which can be favorable reservoir in deep-water.     

Water relation characteristics ofAlhagi sparsifolia and consequences for a sustainable management

Water relation characteristics of the desert legumeAlhagi sparsifolia were investigated during the vegetation period from April to September 1999 in the foreland of Qira oasis at the southern fringe of the Taklamakan Desert, Xinjiang Uygur Autonomous Region of China. The seasonal variation of predawn water potentials and of diurnal water potential indicated thatAlhagi plants were well water supplied over the entire vegetation period. Decreasing values in the summer months were probably attributed to increasing temperatures and irradiation and therefore a higher evapotranspirative demand. Data from pressure-volume analysis confirmed thatAlhagi plants were not drought stressed and xylem sap flow measurements indicated thatAlhagi plants used large amounts of water during the summer months. Flood irrigation had no influence on water relations inAlhagi probably becauseAlhagi plants produced only few fine roots in the upper soil layers. The data indicate thatAlhagi sparsifolia is a drought-avoiding species that utilizes ground water by a deep roots system, which is the key characteristic to adjust the hyper-arid environment. Because growth and survival ofAlhagi depends on ground water supply, it is important that variations of ground water depth are kept to a minimum. The study will provide a theoretical basis for the restoration and management of natural vegetation around oasis in arid regions.

     

New interpretation on the provenance changes of the upper Pinghu–lower Huagang Formation within Xihu Depression,East China Sea Shelf Basin

Both Pinghu and Huagang formations are important hydrocarbon reservoirs of the Xihu Depression in the East China Sea Shelf Basin. Clarifying the source suppliers and restoring source-to-sink transport routes are of great significance to the future petroleum and gas undertakings. Previous researchers were largely confined by either limitation of geological records, highly dependence on a singular method or low-precision dating techniques. Our study integrated heavy mineral assemblages, geochemica...     

Examining locally driven climate change policy efforts in three Pacific states

Local jurisdictions play a critical role in climate change mitigation and adaptation. This study analyzes the theoretical framework of locally driven climate change actions and uses geographic information system (GIS) to map local jurisdictions’ climate change policy efforts in three Pacific states - California, Oregon, and Washington. The results of our study indicate statistically significant differences in geographic clusters and variations across jurisdictions. An Ordinary Least Squares (OLS) regression model was used to examine climate risk, emission stress, and socioeconomic context variables to detect influence on local climate change policy efforts. The explanatory results indicate that coastal proximity, population density, vehicles emission, and education variables significantly influence local jurisdictions’ climate change actions. The findings contribute to local organizational decision model research and can help local communities to develop more effective climate change policies.     

利用卫星遥感资料估算海面太阳辐照度的初步结果

本文在分析了若干由卫星信息提取地表的太阳辐照度物理模式的基础上,将１９９５年５月２６日的ＮＯＡＡ卫星ＡＶＨＲＲ资料经适当变换后,选用Ｈａｙ和Ｈａｎｓｏｎ模式估算并分析了黄渤海３５°～４０°Ｎ、１２０°～１２５°Ｅ海区的海面太阳辐照度值。文中指出,卫星测量可成为海面太阳辐照度观测的有效手段。建议：１）尽快在国内开展这方面的研究;２）应进行海洋实况测量（最好是卫星过境时同步进行）;３）建立从卫星资料提取我国海区海面辐照度的适用算法。     

地层测试评价仪在渤海油田的应用

电缆地层测试是求取储层流体性质、进行储层评价最为直接的方法之一。地层测试评价仪（FET）是国产新一代地层测试评价仪器,不仅可以精确测量地层压力并根据压力剖面确定地层流体类型和油气水界面,而且在目的层取样时可以抽排污染流体、实时检测地层流体特性,对确定地层流体性质和分析流体成分起到了重要作用,同时它也可以计算地层渗透率,进行储层产能预测。通过在渤海油田的成功应用,简单介绍FET的基本工作原理和主要用途,重点论述其优越性和局限性,以及在渤海油田成功应用的典型实例,这对FET在其它油田的推广应用具有参考意义。     

The synchronous coupling of a third-generation wave model and a two-dimensional storm surge model

The interaction of waves and currents is studied by the dynamical coupling of a third generation wave model and a two-dimensional storm surge model. The coupling process of the two models is implemented synchronously. To estimate the effects of waves on the generation of storm surges, the theory of Janssen is used. The effects of the wave radiation stress on surge levels and the effects of storm-induced currents on waves are also investigated.The coupled wave and storm surge models have been tested by hindcasting two storm events in the northern South China Sea. The use of the Simth and Banke stress relation underestimates the surges by 10%. The inclusion of the radiation stress improves the accuracy of the computed results slightly by 2%. The introduction of a wave-dependent surface drag gives a significant improvement. The storm-induced currents clearly affect the wave characteristics at the peak stage. However, as far as the prediction of wave height is concerned, it is better not to consider the wave radiation stress in the storm surge model unless this is accompanied by a wave-dependent surface drag.     

一种高Q值单频水声信号放大提取电路的设计

针对水声信号所处环境复杂、背景噪声源多的特点,提出了一种基于JFET的超低噪音放大电路,该电路选用两片低噪音的场效应管2SK170作为第一级放大器件,经过CR高通滤波连接到同相放大电路,整体电路增益可达70dB;为进一步提升接收信号信噪比,结合双T滤波器特点优化设计出一种高Q值选频电路;通过Multisim14仿真表明,设计的电路在1 Hz处的电压噪声密度仅为2.4 nV/Hz^0.5,滤波器Q值可达25.6,结合实际电路测试结果表明,设计的电路能够满足水声测量要求。     

Field and Theoretical Analysis on the Response of Destructive Pile Subjected to Tension Load

Most field tests are carried out using working piles for verification purposes in China, and loading tests are terminated before achieving true pile capacity. In this work, two full-scale destructive loading tests on tension piles instrumented with strain gauges were conducted to capture true pile capacity. The load-displacement response, load transfer, and threshold of the pile-soil relative displacement for fully mobilizing skin resistance in the uplift case were discussed. It was found that the shaft resistance degradation is observed to be along the pile depth with a reduction factor of 0.905 to 0.931, and the thresholds of pile-soil relative displacement for fully mobilizing skin resistance of the tension pile in different soils are found to be in the range 0.67% to 1.34% of the pile diameter. Based on the field test results, a simple softening model was proposed to describe the degradation behavior of skin friction along the pile-soil interface. Further study was conducted to assess the influence of the threshold of pile-soil relative displacement for fully mobilizing skin friction and the reduction factor on the skin friction. As to the analysis of the response of single pile subjected to tension load, a highly effective iterative computer program was developed using the proposed skin friction softening model. Comparisons of the load-settlement response for the well-instrumented tests were given to demonstrate the effectiveness and accuracy of the proposed simple method.