环境变迁、经济开发与政区演变的相关研究——以上海浦东地区为例

该文以上海浦东地区为典型地域的研究表明 ,政区演变具有内在与外在两种动力机制 ,它们对政区不同要素的作用有所侧重 ,而环境变迁、经济开发等背景因素对政区设置产生的影响 ,具有一定的阶段性。     

中国对虾一种C型杆状病毒随机扩增多态性DNA分析

于１９９４年和１９９５两年的７月从青岛崂山上马镇养虾场中染病的中国地虾中分离纯化出一种Ｃ型杆状病毒。为建立中国对虾病毒的鉴别和检测技术，利用随机扩增多态性ＤＮＡ技术对电泳纯化的病毒ＤＮＡ进行分析和研究。将病虾匀浆、经差速离心和蔗糖密度梯度离心纯化获得完整病毒粒子；从病毒中提取ＤＮＡ后再进行电泳纯化，收集长度完整，均一的病毒ＤＮＡ：在其他参数保持不变的情况下，对Ｏｐｅｒｏｎ生产的１０碱基随机引物Ｋ试     

Multi‐model ensemble prediction of terrestrial evapotranspiration across north China using Bayesian model averaging

Using high‐quality dataset from 12 flux towers in north China, the performance of four evapotranspiration (ET) models and the multi‐model ensemble approaches including the simple averaging (SA) and Bayesian model average (BMA) were systematically evaluated in this study. The four models were the single‐layer Penman–Monteith (P–M) model, the two‐layer Shuttleworthe–Wallace (S–W) model, the advection–aridity (A–A) model, and a modified Priestley–Taylor (PT‐JPL). Based on the mean value of Taylor skill (S) and the regression slope between measured and simulated ET values across all sites, the order of overall performance of the individual models from the best to the worst were: S–W (0.88, 0.87), PT‐JPL (0.80, 1.17), P–M (0.63, 1.73) and A–A (0.60, 1.68) [statistics stated as (Taylor skill, regression slope)]. Here, all models used the same values of parameters, LAI and fractional vegetation cover as well as the forcing meteorological data. Thus, the differences in model performance were mainly attributed to errors in model structure. To the ensemble approach, the BMA method has the advantage of generating more skillful and reliable predictions than the SA scheme. However, successful implementation of BMA requires accurate estimates of its parameters, and some degradation in performance were observed when the BMA parameters generated from the training period were used for the validation period. Thus, it is necessary to explore the seasonal variations of the BMA parameters according the different growth stages. Finally, the optimal conditional density function of half‐hourly ET approximated well by the double‐exponential distribution. Copyright © 2016 John Wiley & Sons, Ltd.     

Hydro-mechanical coupled analysis of near-wellbore fines migration from unconsolidated reservoirs

Oil or gas production from unconsolidated reservoirs could be hampered by sand migration near the wellbore. This paper presents a numerical investigation of production-induced migration of fine sands towards a wellbore drilled in a gap-graded sediment. The solid–fluid interaction is simulated by coupling the discrete element method and the dynamic fluid mesh. With the merit of DEM and a dynamic mesh, the model is capable of naturally capturing particle movements and spatiotemporal variations of hydraulic properties of the sediment at the pore scale. The results show that fine particles are mobilized by radial flow under an imposed hydraulic gradient, and the increase in the hydraulic gradient causes an increase in the fines production. The microscopic pattern of sand migration is clearly visualized through the simulation. The presence of fine particles affects the process of fines migration through two competing mechanisms. Under a low fine content, fine sands mainly serve as the fines production source, and thus, fines production is enhanced as the fine content increases up to a critical value, beyond which fines production is weakened with a further increase in the fine content since the blocking effect gradually dominates. A barrier layer is likely formed during sand migration due to settling and jamming of fine sands at the throats of pores, as fine sands migrate with the radial flow towards the wellbore. This layer is helpful to slow down sand migration, while it could impede production due to reduced permeability in the affected reservoir.

     

A mobile polar atmospheric parameter measurement system:II. First atmospheric turbulence observation at Antarctic Taishan Station

This is the second paper of a series devoted to atmospheric optical turbulence Cn2 observation using a mobile polar atmospheric parameter measurement system. We present the initial results of Cn2 measu...     

新疆地球化学景观区划分及意义

系统地划分了新疆地球化学景观区，并在典型景观区方法试验基础上，提出了相应景观区中矿产地球化学勘查方法技术建议，为今后在类似景观区开展矿产地球化学勘查工作提供了借鉴和参考。     

银洞子银铅矿床重晶石岩的地球化学特征

重晶石岩是银洞子银铅矿床中重要的热水沉积岩，其化学成分较纯，微量元素含量比较贫乏，ＲＥＥ含量较低，具有强烈的角肴异常和不明显的铈异常，δ＾３４Ｓ值与同期海水硫酸盐相似，是在中－低温、较酸性、弱氧化环境中由快速的热水沉积作用形成的。