Sidewall effects and sand trap efficiency in a large wind tunnel

Aeolian sand transport is a widespread physical phenomenon on the surface of Earth, as well as on Mars and Titan. Accurate measurements of the components of the transport system are necessary if we are to understand the nature of the physical processes. Sand traps are typically used to measure sediment transport rates, and issues associated with the sampling efficiency of traps and the development of reliable traps have received considerable attention in recent decades. In this study, we measured aeolian transport rate at five distances from a wind tunnel sidewall using a vertically‐segmented sand trap. Total transport rates were determined by weighing the bed sediment before and after each experiment, and with and without a trap installed. The following results were obtained: (1) sand transport increased linearly with the distance away from the sidewall, and the appropriate location to measure maximum transport is within the central 20% of the wind tunnel; (2) current methods overestimate the sampling efficiency of sand traps when comparing trap data to transport rate data obtained by weighing sand moved through the entire tunnel because the effects of the sidewalls in decreasing total transport are neglected; (3) the efficiency of the vertically‐segmented trap that we tested ranged from 11.57% to 31.68% using our revised methods, whereas standard methods caused efficiency to be overestimated by 32–72% of the efficiency; (4) using either method, the efficiency of the trap increased exponentially with shear velocity for the range we used. Copyright © 2017 John Wiley & Sons, Ltd.     

Problems and Solutions in Pesticide Analysis Using Solid‐phase Extraction (SPE) and Gas Chromatography Ion‐trap Mass Spectrometry Detection (GC‐MS)

In the present study an analytical method was tested for the determination of selected pesticides and metabolites using solid‐phase extraction (SPE) and gas chromatography ion‐trap mass spectrometry (GC‐MS). The extraction efficiency of C18, Isolut ENV+, and Lichrolut EN for SPE was compared for trifluralin, fenitrothion, endosulfan, propargite, 2,4‐D, 3‐methyl‐4‐nitrophenol, 2‐(4‐tert‐butylphenoxy)cyclohexanol, endosulfan sulfate, and 2,4‐dichlorophenol. Isolut ENV+ and C18 showed good results as sorbents and acetone as an elution solvent for SPE for the selected pesticides. Recoveries varied between 36% and 176% with a relative standard deviation of 2...18%. Because of coextracts from the SPE materials, recovery values higher than 100% were obtained for fenitrothion, endosulfan sulfate, and 2,4‐D with C18 as well as for endosulfan sulfate and 3‐methyl‐4‐nitrophenol with Isolut ENV+. A standard addition method was used to verify the occurrence of coextracts in the sample after SPE.     

油气圈闭定量化地质评价

在定量化地质方法评价圈闭含油气性的过程中,首先用区域地质资料、钻井资料、地震资料等建立这个地区的数值模板,其次就是把要评价的圈闭地质条件和这个模板作比较。然后给这些圈闭评分。最后用数学方法对这些评分进行计算。其计算结果就表示圈闭评价结果,数值越高,评价效果也越高。     

涠西南凹陷二号断裂带断裂控藏研究及应用

涠西南凹陷是勘探开发一体化研究重点区,本文以二号断裂带为研究对象,综合断裂动力学特征、运动学特征、几何学特征等研究,将中段“坡坪式”断裂体系、两侧“铲式”断裂体系等差异性断裂体系内部划分为3级雁列式主断裂、4级分支断裂、5级分支断裂。中段“坡坪式”断裂体系受到更高强度地应力作用,主断裂与分支断裂更为发育,二号断裂带绝大多数油气分布于此。综合分析二号断裂带差异性断裂体系内部断裂系统与油气展布规律之间的关系,得到3方面断裂控藏规律及4种优势断裂控藏模式。在断裂控藏规律及断裂控藏模式的指导下,搜索、优选二号断裂带中段北1块、北3块、北4块潜力目标进行评价、实施。3个潜力区块均实施成功,达到地质油藏目的,断裂控藏规律、断裂控藏模式在涠西南凹陷二号断裂带潜力区块应用效果好。     

Fast generation of cluster states in a linear ion trap

We propose a practical scheme to generate cluster states by simultaneously accomplishing two-qubit conditional gating on an array of equidistant ions by using transverse modes. Our operation is robust to heating and insensitive to Lamb--Dicke parameter. Meanwhile, as it is carried out in a geometric quantum computing fashion, our scheme enables the fast and high-fidelity generation of cluster states. The experimental feasibility is discussed with sophisticated ion trap techniques.     

油气差异聚集原理应用效果分析——以黄河口凹陷为例

黄河口凹陷是渤海湾盆地的富烃凹陷之一,近几年勘探发现原油超过2×108m3,天然气超过100×108m3,成果显著。但成功的背后,仍存在众多疑问：地质条件良好的构造上竟然钻了干井,同一个油源的相似构造,钻井结果有的以油层为主,而有的井含气层位多;同一深度段的油层,在不同井中原油密度却存在较大差异。为解决这些疑问,笔者运用差异聚集原理,首先对黄河口凹陷渤中28-2E空圈闭的形成原因进行了分析,建立了本区油气运移的模式。在此模式的指导下对渤中29-4构造开展了评价,准确预测了该构造含油气区域的分布范围,结果证明黄河口凹陷的油气运聚符合差异聚集原理。该原理能够很好的指导本区下一步的勘探,可以取得很好的经济效益。     

High downward flux of mucilaginous aggregates in the Ligurian Sea during summer 2002: similarities with the mucilage phenomenon in the Adriatic Sea

The DYFAMED sediment trap station in the Ligurian Sea (NW Mediterranean) has been active since 1986 and today comprises the longest time‐series of downward particle flux in the Mediterranean Sea. As such, it provides valuable information on the interannual variability of the particle flux, and also documents possible recent changes in the NW Mediterranean pelagic ecosystems. We report an unprecedented episode of downward flux of mucilaginous material at the DYFAMED station during summer 2002 in association with singular hydrometeorological conditions. The rain of mucilaginous aggregates clogged a PPS5 sediment trap at 260 m depth and was also clearly detected at 1080 m depth. The possible factors governing the development and sinking of the mucilaginous material are discussed. A very sharp increase of sea surface temperature during June and the presence of freshened waters in the surface the following month resulted in a stronger than usual stratification of the upper water column throughout the summer season. We suggest that the steepness of the vertical density gradient was responsible for the unusual accumulation of mucous aggregates. Additionally, a diatom bloom took place during the nutrient‐depleted conditions typical of summer, a factor which may have contributed to feed the pycnocline with transparent exopolymer substances. A storm occurring in the beginning of August relaxed the stratification and promoted the deposition of the mucilaginous aggregates accumulated in the upper water column during the preceding months. Important similarities of ambient conditions preceding the apparition of mucilaginous material in our open‐sea site and those reported in the Adriatic Sea during major mucilage events, suggest that general climatic conditions, rather than local factors, drive the occurrence of major accumulations of mucilaginous material in the water column at both sub‐basins of the Mediterranean Sea. In this regard, the strength of the air temperature increase during the onset of the stratified season is proposed as a major controlling factor.     

海洋激流的观测实验及分析讨论

海洋中存在着冲击力极强的海洋激流,这已是不争的事实.从20世纪70年代起,一些国家就开始对大洋海底激流进行现场观测.据报道,他们所观测到的异常的底层流速的最大值仅为0.4m/s,却被视之为海底激流加以分析研究[1～5].     

北部湾盆地涠西南凹陷油气成藏条件分析

涠西南凹陷位于北部湾盆地西南部,发育有多个油气田(含油气构造)。以油气地质理论为指导,在构造和沉积地层特征研究的基础上,重点分析了烃源岩、储集层、圈闭及输导介质等油气成藏的基本要素,认为涠西南凹陷拥有较好的烃源岩、发育多套储集层、多种类型圈闭和复合的输导介质,具备油气藏形成的基本条件,具有广阔的油气勘探前景。     

前陆盆地斜坡带低幅度构造地球物理识别技术

为了有效识别前陆盆地斜坡带低幅度含油气构造,深入剖析了低幅度构造圈闭及油藏特征,围绕储层地震预测开展了针对性的地球物理识别技术研究.在南美西北部奥连特-马拉农盆地多个区块进行了储层的岩性、形态、物性及含油气性等方面的预测,形成了一整套基于高精度地球物理资料的低幅度构造和岩性圈闭识别和描述的精细地震解释技术.