智能型岩心流动梯度仪设计

智能型岩心流动梯度仪采用岩心轴向不同深度设置测压点的方法 ,测定岩心的整段以及分段渗透率参数 ,从而对地层的非均质性以及生产作业措施对油层的损害程度和深度进行评价。文章介绍了智能型岩心流动梯度仪的测试原理、结构特点以及软件功能等。该仪器的开发 。

钨合金丝材无模拉拔成形温度场及流动应力梯度

简述了目前钨合金丝材加工技术特点及变形过程存在的技术问题,分析了采用无模拉拔成形技术加工钨合金丝材的可行性及变形机制。通过实验研究,确定了钨合金丝材无模拉拔成形的温度场模型和流动应力模型,确定了钨合金丝材无模拉拔成形变形区温度梯度及流动应力梯度。研究结果表明,钨合金丝材无模拉拔成形时,当Z≤ZM时变形区温度场沿轴向呈线性分布;当Z>ZM时变形区温度场沿轴向呈非线性分布,温度梯度沿轴向呈线性分布;变形区流动应力场沿轴向接近线性分布,流动应力梯度接近于常数。

平行平板间电流变液非零压力梯度Couette流动的稳定性分析

采用Rajagopal和Wineman所提出本构方程 ,对电流变液在二维平行平板间非零压力梯度Couette流动的线性稳定性问题进行研究。通过分析和数值计算发现 ,任何壁面运动都将使流动稳定性增强。在外加电场存在的情况下 。

我国农村劳动力“反梯度”流动的经济学分析——以新疆采棉工为例

农村劳动力"反梯度"流动是我国经济和社会转型期间出现的一种特殊现象。从流向看,它有悖于劳动力由乡—城、由落后地区—发达地区流动的规律。文章采用经济学分析方法,以新疆采棉工为研究对象,从理论和现实两个层面研究分析采棉工理性的流动决策行为以及基本特征和相关影响因素。

钨合金丝材无模流变成形温度梯度及流动应力梯度

分析了目前钨合金丝材加工技术特点、变形过程存在的技术问题 ,分析了采用无模流变成形技术加工钨合金丝材的可行性及变形机制 ,确定了钨合金丝材无模流变成形的温度场模型和流动应力模型 。

流动注射梯度稀释法在原子吸收分析中的应用

提出了应用流动注射梯度稀释法与原子吸收光度法相结合 ,样品不经稀释便可同时测定酸雨中不同浓度的钙。

梯度流体剪应力下细胞膜张力的数值模拟

目的分析梯度流体剪应力(fluid shear stress,FSS)流场中细胞膜张力分布。方法构建梯度平板流动腔模型,采用流固耦合数值模拟方法,研究不同FSS梯度和幅值、不同静水压下细胞膜的膜张力分布。结果当流动腔入口流量增大时,FSS流场梯度呈正比例增大。梯度FSS流场下,细胞膜张力由贴壁侧向顶部呈先减小后增大的趋势。在正常人体血压下,静水压越大,细胞膜张力越大。当FSS幅值一定时,增加FSS梯度,细胞高、低FSS区域平均膜张力差值增大;当FSS梯度一定时,增加FSS幅值,细胞高、低FSS区域平均膜张力差值增大。结论梯度FSS流场会引起细胞膜张力的局部差异,其可能是破骨前体细胞在梯度流场中定向迁移的重要原因。

高效液相色谱仪中等度和梯度洗脱对吡虫啉及多菌灵杂质峰的影响

高效液相色谱仪是现代农药残留检测的重要设备之一,它具有检测时间短、准确度、灵敏度高等特点,是我国现代农业水果蔬菜农药残留检测中重要组成部分,高效液相色谱仪分析样品时分等度洗脱和梯度洗脱两种模式,用等度洗脱进行色谱分离时,指用不同溶剂构成的流动相组成相同,从而使流动相的离子强度、pH值、极性等,在分离的全过程中保持不变。而用梯度洗脱进行色谱分离时,在洗脱过程中含2种或两种以上不同极性溶剂的流动相组成会连续或间歇地随时间的改变而改变,从而改变流动相的配比和流动相的极性,改善样品中各组分间的分离度。从而导致杂质峰前移或推后,使得杂质峰和主峰更好地分离开,能减少检测中杂质峰对检测结果的影响。

聚合物驱、调剖后聚合物驱三维模型驱油效果评价

模拟大庆某注聚油藏 ,制作了包含渗透率和厚度不同的 4个小层的三维非均质物理模型 ,尺寸 80× 80× 4.6 (cm) ,中央设注入井 ,四角设采出井 ,驱替中测定每层测量网点上的压力和电阻率 ,由电阻率求出该点含水率和含油率。驱替程序如下 :水驱至含水 93% ,注入 10 0 0mg/L聚合物溶液 0 .5 7PV(模型 1,聚合物驱 )或先注入 0 .0 3PV调剖剂 ,成胶后注入 0 .5 4PV聚合物溶液 (模型 2 ,调剖 +聚合物驱 ) ,最后均水驱至含水 98% ,实验温度45℃。与聚合物驱相比 ,调剖 +聚合物驱中注聚采收率提高 2 .16 % ,最终采收率提高 2 .18% ,含水率下降滞后(最低点由 1.0 7PV移至 1.33PV) ,注聚后采收率上升也滞后。模型第 3层注入井到 3号采出井方向上 (含高渗条带 ) ,调剖 +聚合物驱中前一段压力梯度增幅较大 ,后一段则较小 ,这是强凝度调剖剂封堵了高渗条带的结果。给出了驱替结束时两个模型各层油饱和度分布图。聚合物驱后的油饱和度 ,第 1和第 4层分别为 0 .42和 0 .48,第 3层 1,2 ,4号采出井方向上为 0 .5 4,3号采出井方向上为 0 .42。与聚合物驱相比 ,调剖 +聚合物驱后第 3层各方向上油饱和度分布趋于均匀 ,第 3层采出油量略减少 。

耗散结构理论与心身医学

耗散结构理论主要研究系统由无序向有序转化的机制、条件和规律。该理论可应用于心身医学研究,促使机体生命系统形成并维持耗散结构状态。1.生命系统必须开放适时,适度引入负熵流,减少机体内熵增加。2.通过非线性反馈机制,提高机体有序度,保证正常生命活动进行。3.生命系统应远离平衡态、维持负熵流动梯度,促进心身健康发展。

当代世界技术贸易的地理格局初探

本文在论述当代国际技术贸易地理分布的基础上分析了当代国际技术贸易的流动特点，并探讨其成因，最后指出了当代国际技术贸易地理的主要研究领域。

制备型高效液相色谱在生物医药制品领域的应用

制备型高效液相色谱(preparative high performance liquid chromatography,Prep-HPLC)是一种使用高压、大流量液体输送系统在高分辨率、大内径、高载量分离柱上进行样品高纯度分离的液相色谱制备方法.应用该方法分离的产品在纯度、回收率、分离效率等方面远远优于传统的制备方法,因此在生物制品和药物研究、生产领域得到广泛应用[1-3].本文就近年来Prep-HPLC方法的研究进展及其在生物医药制品领域的应用做一综述.……

人口梯度流动背景下的彝族农业移民研究

在中国城乡一体化改革进程中,大批农民进入城镇务工。已有研究对少数民族农民向汉族农村的人口流动关注极少,然而这类具有差异性的农村内部的流动,是和当代城市化进程紧密关联。因为只有在汉区农村农民向城市大规模流动之时,才可能有民族地区农民向汉区农村的梯度推进。作者选择以四川省仁寿县为例,对彝族农民向仁寿县汉区农村的人口流动进行全方位的实地调查研究,并总结提出独特的彝族农业移民管理建议。

Characteristics of unsteady flow in porous media while considering threshold pressure gradient with Green＇s function

The flow behavior in porous media with threshold pressure gradient(TPG) is more complex than Darcy flow and the equations of motion, and outer boundary and inner boundary with TPG are also different from Darcy flow for unsteady flow of a producing well in a reservoir. An analytic method to solve this kind of problem is in a need of reestablishment. The classical method of Green's function and Newman product principle in a new way are used to solve the unsteady state flow problems of various shapes of well and reservoir while considering the TPG. Four Green's functions of point, line, band and circle while considering the TPG are achieved. Then, two well models of vertical well and horizontal well are built and simultaneously the function to calculate the moving boundary of each well model is provided. The results show that when considering TPG the pressure field is much different, which has a sudden pressure change, with a moving boundary in it. And the moving boundary of each well model increases with time but slows down rapidly, especially when the TGP is large.

Spatial Distribution of Land Cover and Vegetation Activity along Topographic Gradient in an Arid River Valley, SW China

Anthropogenic activities have become more and more important in characterizing the landscape, but their impacts are still restricted by natural environments. This paper discusses the interactions of anthropogenic activity, vegetation activity and topography through describing the spatial distribution of land cover and vegetation activity (represented by Normalized Difference Vegetation Index, NDVI) along topographic gradient in a mountainous area of southwestern China. Our results indicate that the existing landscape pattern is controlled by anthropogenic activities as well as topographic factors. Intensive anthropogenic activities mainly occur in areas with relatively low elevation, gentle and concave slopes, as these areas are easy and convenient to attain for human. Because of the destruction by human, some land cover types (mainly grassland and shrub) are only found in relatively harsher environments. This study also finds that topographic wetness index (W) used in other places only reflects runoff generation capacity, but not indicate the real spatial pattern of soil water content in this area. The relationships between NDVI and W, and NDVI and length slope factor (LSF) show that runoff and erosion have complex effects on vegetation activity. Greater values of W and LSF will lead to stronger capacity to produce runoff and transport sediment, and thereby increase soil water content and soil deposition, whereas beyond a certain threshold runoff and erosion are so strong that they would destruct vegetation growth. This study provides information needed to successfully restore native vegetation, improve land management, and promote sustainable development in mountainous areas, especially for developing regions.

Turbulence Model Investigations on the Boundary Layer Flow with Adverse Pressure Gradients

In this paper, a numerical study of flow in the turbulence boundary layer with adverse and pressure gradients （APGs） is conducted by using Reynolds-averaged Navier-Stokes （RANS） equations. This research chooses six typical turbulence models, which are critical to the computing precision, and to evaluating the issue of APGs. Local frictional resistance coefficient is compared between numerical and experimental results. The same comparisons of dimensionless averaged velocity profiles are also performed. It is found that results generated by Wilcox （2006） k-co are most close to the experimental data. Meanwhile, turbulent quantities such as turbulent kinetic energy and Reynolds-stress are also studied.

Finite element simulation on percolation of low permeability reservoir with permeability anisotropy

In low permeability porous media which permeability anisotropy is ubiquitous,the percolation of fluid no longer follows linear Darcy’s Law.Oil-water two phase flow equation of low permeability reservoir with permeability anisotropy is established based on generalized Darcy’s law and starting pressure gradient,corresponding finite element program is developed and simulated based on the Finite Element Program Generator system (FEPG).The results show that energy-gathering exists in the flow event of flowing area front in low permeability reservoir.In the process of energy-gathering,the flow velocity changed little but increased rapidly as soon as the pressure gradient exceeded the starting pressure gradient of the reservoir,then gradually stabilized.The greater the starting pressure gradient is,the greater the near wellbore pressure drop is,the smaller the area influenced by the reservoir pressure changes caused by water injection and oil recovery.The greater the starting pressure gradient is,the lower the water saturation in same point of the reservoir is,the smaller the water flood swept area is.There will be more difficulties in water injection to the same extent.

快速测定白酒中甜味剂-超高效液相色谱串联质谱法可行性研究

目的:研究超高效液相色谱-串联质谱检测方法对白酒中甜味剂(安赛蜜、糖精钠、甜蜜素和三氯蔗糖)检测的可行性;方法:使用Agilent ZORBAXSB-C18色谱柱(50 mm×2.1 mm,1.8μm)分离,以0.1%甲酸水溶液-甲醇作为流动相梯度洗脱,在电喷雾离子源ESI负离子模式下多重反应监测(MRM)定性、定量测定甜味剂;结果:4种甜味剂在10μg/L^500μg/L浓度范围内呈现良好的线性关系(r≥0.999);检出限为0.5~2.4μg/L,加标回收率在89.4%~104.6%之间,RSD小于4%;

Magnetorheological finishing of low-gradient curved surfaces based on four-axis linkage technique

Based on the distribution characteristic of magnetic field along the polish wheel,the four-axis linkage technique is advanced to replace a standard five-axis one to figure low-gradient optical surfaces with a raster tool-path in magnetorheological finishing(MRF).After introducing the fundaments of such simplification,the figuring reachability of a four-axis system for the low-gradient optics was theoretically analyzed.Further validation including magnetic field intensity and influence function characteristic was performed to establish its application.To demonstrate the correctness,feasibility and applicability of such technique,a K4 spherical part was figured by two iterations of MRF with surface form error improved to 0.219λPV and 0.027λRMS.Meanwhile,the surface roughness was also improved a lot in MRF process.These theoretical analyses and experimental results both indicate that high form accuracy and excellent surface quality can be obtained by using the four-axis linkage technique in the process of figuring low-gradient optical elements,and the four-axis linkage system undoubtedly is much more easy to control and much more economical.

根据具体情况优化EPA8310中色谱分离条件

运用Agilent(安捷伦)1200系列高效液相色谱和多环芳烃专用柱ZORBAX Eclipse PAH(4.6×250mm、5μm,P.N.959990-918,S.N.USPAB01066),对16种多环芳烃化合物混合溶液进行分析,根据具体实验条件优化EPA8310中色谱分离条件并得到了更节省时间、分离效率更好的流动相梯度变化程序。