Experimental investigation of different brines imbibition influences on co-and counter-current oil flows in carbonate reservoirs

Imbibition of water,as wetting phase in oil-wet fractured carbonate reservoirs,plays a key role in fluid flow between matrix and fracture system.The type of injected seawater and its chemistry would profoundly influence the imbibition process.In this study,the impact of smart water(a brine that its ions have been adjusted to facilitate oil recovery)and low salinity water on co-and counter-current imbibition processes for oil-wet carbonate cores has been experimentally investigated.The results show an increase of about 10% in oil recovery for co-and counter-currents for smart seawater imbibition compared to that of low salinity seawater.In addition,as a result of the influence of co-and counter-current on each other,by co-current removal from one core face,the countercurrent in the other face would be intensified by as much as about 75%.A close examination of different lengths(5,7 and 9 cm)of carbonate cores with the same permeability revealed that by decreasing porous medium length,the amount of counter-current producing oil would be decreased so that in the 5 cm core,counter current oil production will not happen.For similar core lengths by increasing permeability,the share of counter current flow would be decreased approximately 18% since the capillary pressure could not overcome non-wetting phase viscous forces.Considering the role of matrix length along with a modified brine(which is designed according to the matrix mixture)strengthen the relevant mechanisms to have more oil production so that the higher thickness of matrix causes the higher amount of co-current oil producing and consequently more total recovery.

Preparative isolation and purification of 12,13-dihydroxyeuparin from Radix Eupatorii Chinensis by high-speed counter-current chromatography

An efficient method for the isolation and purification of 12,13-dihydroxyeuparin from Radix Eupatorii Chinensis by high speed counter-current chromatography (HSCCC) was established in this paper. The ether extracts of Radix Eupatorii Chinensis were purified by HSCCC with a solvent system of hexyl hydride-ethyl acetate-methanol-water (1:2:1:2, v/v/v/v). The upper phase was used as the stationary phase and the lower phase as the mobile phase. About 8.4 mg of 12, 13-dihydroxyeuparin was obtained from 200 mg of ether extracts from Radix Eupatorii Chinensis in one-step HSCCC separation, with the purity of 96.71%, as determined by HPLC. After methanol- water recrystallization, the purity of 12,13-dihydroxyeuparin reached 99.83%. Such a simple and effective method was fairly useful to prepare pure compound as reference substances for related study on Radix Eupatorii Chinensis.

Counter-Wind Deep Current in the Northern Beibu Gulf in Boreal Winter

The Beibu Gulf is at an important geographical location and rich in gas, oil and biological resources. The observed currents showed that the current in the upper layer was opposite to that in the lower layer in boreal winter in the northern Beibu Gulf and it was northeastward in the lower layer. This northeastward current was reproduced by a 3 D baroclinic model in this study. It's found that the counter-wind deep current(referred to as ‘CWDC' hereinafter) strengthened from September to November but weakened from December to the following February. A closed meridional circulation in vertical direction was found in the northern Beibu Gulf, including CWDC, surface southwestward current, an upwelling, and a downwelling. The temporal variation process of the meridional circulation was similar to that of CWDC, with strength and range stronger in November and December than in other four months. Similar to the variation process of CWDC, the monsoon wind changed from weak easterly wind in September to strong northeasterly wind in November and December, and it was transformed into weak southeasterly wind in February again. The sensitive experiments showed that CWDC and the meridional circulation were controlled by the monsoon wind and were adjusted by heat flux-and tide-induced mixing, respectively. According to the momentum balance equation, it can be revealed the counter-wind deep current is a compensation current which is induced by the surface elevation gradient balanced by the Coriolis force, vertical diffusion and baroclinic pressure gradient.

An Economical Method for Preparative Purification of Five Alkaloids from Coptis Chinensis Franch by High-Speed Counter-Current Chromatography Using Singled Prepared Solvent System by GC

Coptis chinensis Franch, a widely used Traditional Chinese Medicine, shows various kinds of bioactivity. The major active components of the herb are considered to be alkaloids. Thus, preparative separation of these alkaloids is critical important for further pharmacology and mechanism studies. In the paper, five alkaloids from C. chinensis were purified by HSCCC using the solvent system composed of chloro-form-metha- nol-water (2:1:1, v/v/v) single prepared. The content of each solvent in solvent system were determined by gas chromatography (GC), then according the ratios of solvents in each phase to prepare the mobile and stationary phase respectively. And a comparative study was carried out between together preparation and single preparation of the solvent system. The purities and recoveries of all the products were over 98.5% and 92%. However, 134 mL chloroform, 336 mL methanol and 452 mL water were saved when the two phase were singled by GC. Our research showed an economical method for separating alkaloids from C. chinensis by HSCCC using the solvent system single prepared by GC.

Rapid and Continuous Extraction of Methyl Red from Wastewater Using Counter Current Chromatography

A new prototype and simple low speed counter current chromatography (LSCCC) has been fabricated and a laboratory work has been carried out for rapid and continuous removal of methyl red from wastewater using xylene as an extractant. The distribution ratio (D) and percentage of recoveries were calculated. The optimum concentration for extraction of methyl red was in the range of 2 × 10-4 to 8 × 10-4 mol·L-1. Maximum extraction achieved at pH range of 2 to 4.5. Various dye concentrations and solvent effects were studied to optimized conditions. It was shown that when the ratio of the organic phase to aqueous phase increased to more than 3:1, the striping efficiency decreased sharply. The experiments were carried out for 5 times and the highest extraction achieved was 99.8 per cent by two-solvent system LSCCC in just 5 minutes. Real wastewater samples were analyzed and the efficiency of the technique was compared with liquid-liquid extraction (LLE). In practice it was shown that although both techniques are rapid, the efficiency of the LSCCC is much better than LLE.

Separation and Purification of Acetophenones from Cynanchum bengei Decne Root Bark by Combination of Silica Gel and High-speed Counter-current Chromatography

[Objectives] To develop a method for separation and purification of acetophenones from Cynanchum bengei Decne root bark by combination of silica gel and high-speed counter-current chromatography( HSCCC). [Methods]The crude extract of Cynanchum bengei Decne root bark was separated by silica gel column chromatography,and parts A and B containing acetophenones were obtained. Then,parts A and B were separated by HSCCC with a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water( 4∶ 6∶ 4. 5∶ 5. 5 and4∶ 6 ∶ 3 ∶ 7, V/V), respectively. [Results] From 260 mg of part A, four compounds with p-dihydroxybenzene 3. 9 mg(Ⅰ),4-hydroxyacetophenone 17. 1 mg( Ⅱ),2,5-di-hydroxyacetophenone 13. 3 mg(Ⅲ) and 2,4-dihydroxyaceto-phenone 21. 0 mg(Ⅳ) were obtained. And from 300 mg of part B,136 mg of Radix Cynanchi Bungei benzophenone(Ⅴ) was obtained. The purity of compounds determined by HPLC was 97. 0%,96. 6%,99. 2%,99. 7%,99. 5%,respectively. [Conclusions] The established method is simple and efficient. It can be used for separation of acetophenones from Cynanchum bengei Decne root bark and has better practical value,which could provide a reference basis for development and utilization of Cynanchum bengei Decne root bark.

Comparison of Co-Current and Counter-Current Flow Fields on Extraction Performance in Micro-Channels

Several applications such as liquid-liquid extraction in micro-fluidic devices are concerned with the flow of two immiscible liquid phases. The commonly observed flow regimes in these systems are slug-flow and stratified flow. The latter regime in micro-channels has the inherent advantage that separation of the two liquids at the exit is efficient. Recently extraction in a stratified counter-current flow has been studied experimentally and it has been shown to be more efficient than co-current flow. An analytical as well as a numerical method to determine the steady-state solution of the corresponding convection-diffusion equation for the two flow-fields is presented. It is shown that the counter-current process is superior to the co-current process for the same set of parameters and operating conditions. A simplified model is proposed to analyse the process when diffusion in the transverse direction is not rate limiting. Different approaches to determining mass transfer coefficient are compared. The concept of log mean temperature difference used in design of heat exchangers is extended to describe mass transfer in the system.

矿渣水泥基复合材料在杂散电流作用下的抗软水溶蚀机理研究

在轨道交通工程运营期间,复杂的服役环境导致混凝土结构耐久性下降。本文主要研究了在杂散电流与软水溶蚀耦合作用下,矿渣掺量、水胶比和杂散电流电压强度对矿渣水泥基复合材料微观结构的影响。结合X射线衍射、热重、扫描电子显微镜和压汞等方法,分析了矿渣水泥基复合材料经溶蚀90 d后的物相组成、Ca(OH)_(2)含量、微观形貌以及孔结构变化。研究结果表明:矿渣掺量越大,矿渣水泥基复合材料内部的Ca(OH)_(2)含量越少,材料的孔隙率越低,结构更均匀致密;随着杂散电流电压强度的增加,矿渣水泥基复合材料内部的Ca(OH)_(2)和AFt含量变少,且AFt和Ca(OH)_(2)等物相边界变得模糊不清;矿渣水泥基复合材料中C-(A)-S-H的含量略有增多,孔隙率略有下降;随着水胶比的增大,矿渣水泥基复合材料内部的Ca(OH)_(2)含量变少,剩余物相含量变少,微观结构变得松散多孔,孔径结构整体粗化,孔隙率增大。

蜘蛛网流道冷板冷却液对向流锂离子电池散热分析

锂离子电池工作温度过高或温差过大将导致其容量降低和寿命缩短。为了降低其工作温度及温差,设计了一款蜘蛛网流道冷板,采用数值方法对其冷却液对向流锂离子电池散热进行了计算。比较了蜘蛛网流道冷板冷却液对向流与同向流锂离子电池的散热情况,分析了冷却液流量以及冷板内流道夹角、槽深、壁厚对电池散热的影响。结果表明:与冷却液同向流电池相比,冷却液对向流电池最高温度、温差都降低,电池温度分布更加均匀。在0.02~0.06 kg/s区间,随着冷却液流量增大,电池最高温度和温差快速降低,而冷却液压降缓慢增大;当冷却液流量大于0.06 kg/s时,随着冷却液流量增大,电池最高温度和温差缓慢降低,而冷却液压降快速增大。增大流道夹角可使流道在冷板内分布更加均匀,提高冷板散热能力。当冷却液质量流量恒定时,增大流道槽深可使冷却液压降显著减小,但会引起电池最高温度和温差略微升高。随着流道壁厚增大,电池最高温度和温差均呈下降趋势。蜘蛛网流道冷板在流道夹角80°、槽深1 mm、壁厚2 mm、冷却液流量0.06 kg/s对向流冷却条件下,可使锂离子电池3C放电最高温度和温差降至31.02℃和4.54℃。

基于反电动势的地铁牵引电机电流传感器故障检测与容错控制

针对地铁列车牵引系统电流传感器发生故障时给列车运行带来重大安全风险这一问题,提出了一种新型的故障监测与容错控制算法。首先,利用三相异步电机的静态数学模型结合转子磁链与反电动势的特定关系设计了电流滑模观测器。然后,将电流传感器的测量值与滑模观测器中的估计值进行比对并生成电流残差,通过修正的Bayes分类算法对电流传感器工作状态进行实时监测与定位。当故障发生时用观测器中的电流重构值代替故障值参与系统的控制。最后,利用仿真平台MATLAB/Simulink对其有效性进行验证并与另外3种典型的控制算法进行对比分析。研究结果表明,方案具有较高的精度和较强的鲁棒性,在对三相电流重构方面优于对比方案,其系统综合误差减小了24.2%,具有更好的控制效果。

Enhanced recovery of high-purity Fe powder from iron-rich electrolytic manganese residue by slurry electrolysis

Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.

废炼油催化剂酸浸液中镍的选择性萃取

针对废炼油催化剂酸浸液中的镍,研究了以HBL110为萃取剂进行直接选择性萃取。优化了萃取剂皂化率、萃取剂浓度、萃取平衡时间,确定了萃取与反萃取级数,并进行了实验室多级逆流串联萃取模拟试验及线上流程的连续萃取试验。结果表明:在皂化率40%、HBL110浓度25%、萃取时间10 min条件下,经五级逆流萃取,萃余液中镍质量浓度低于30 mg/L,镍萃取率达98%以上,Al、Fe萃取率低于3%;以75 g/L硫酸对镍负载有机相进行三级逆流反萃取可100%实现镍的反萃取;对废催化剂酸浸液进行线上萃取流程连续运行5 d,萃余液中镍质量浓度稳定在5 mg/L,镍萃取率达99%,反萃取液中镍质量浓度稳定在8 g/L,镍反萃取率为100%,有机相可以实现有效的循环再利用。

无患子皂苷连续管式逆流超声辅助提取的釜式微分模拟研究

借助工业生产(行业)公认的“萃取”扩展定义,以尊重原理、“化繁为简”、“实施可行”的理念,对无患子皂苷连续管式逆流超声辅助提取的工艺过程展开了“釜式微分提取”的模拟研究。结果表明,不同提取阶段的提取液皂苷含量与其相对应的进料液皂苷含量之间的函数关系为Y=0.0188x^(4)-0.0389x^(3)-0.2866x^(2)+0.6108x+1.4536,R^(2)=0.7108。从数理统计学的角度,可以将它看作是“连续管式逆流超声辅助提取无患子皂苷的动力学行为关系”。

城市轨道交通计轴设备受干扰分析及解决方案

城市轨道交通系统采用交流供电模式时常发生牵引供电回流干扰计轴设备的问题,针对该问题,分析计轴系统工作原理,对某市域轨道交通线路发生计轴设备受扰问题进行监测、试验、分析,并提出有效的解决方案。

钢管密闭塔水平圆管降膜热质传递规律研究

冷却塔通过热质交换将高温介质的热量从系统排放到大气,从而达到冷却效果。对钢管密闭式冷却塔水平圆管降膜蒸发器传热传质的影响因素进行研究与分析,搭建逆流式密闭塔水平圆管降膜传热传质性能研究可视化实验台,主要研究气流速度、喷淋密度、喷淋水温度对横管降膜蒸发传热传质性能的影响。在给定实验工况下,得出当最佳喷淋密度为0.0416 kg/(m·s),对应的最大总换热系数为1625.01 W/(m^(2)·K);当最佳喷淋水温度为16.82℃,对应的最大总换热系数为1736.86 W/(m^(2)·K);最佳气流风速在1~2 m/s之间。

杭州地铁1号线计轴红光带问题分析及解决方案

[目的]在杭州地铁1号线三期区段动车调试及试运行过程中,在线路不同位置处,计轴设备均出现了受扰异常占用(红光带)的情况,严重影响了地铁的运营安全。因此,有必要对异常受扰场景进行分析和测试试验,选择合适的改进方案解决计轴设备的受扰异常占用问题。[方法]介绍了列车通过1号线三期计轴区段异常受扰占用情况;分析了列车牵引设备回流与计轴设备干扰谐波之间的关系,并进行了相关调查测试及验证;提出了列车牵引设备与计轴设备工作频段重叠产生干扰谐波的解决方案。[结果及结论]对于1号线三期工程列车通过三期计轴区段异常受扰占用(红光带)情况,可采用优化列车牵引系统设备工作频率参数的方法解决该问题,错开列车牵引设备工作频段与计轴设备工作频段,以解决设备的同频干扰问题。

脑前额叶区经颅直流电刺激对纵跳能力影响的时效性研究

目的 探讨经颅直流电刺激(transcranial direct current stimulation, t DCS)对纵跳(counter movement jump, CMJ)能力的影响。方法 21名普通大学生(普通大学生组)和17名大学生运动员(运动员组)随机接受脑前额叶区2 m A、20 min的真刺激(anodic t DCS,a-t DCS)或假刺激(sham t DCS,s-t DCS),采集刺激后即刻及10、20、30、40 min时间点的CMJ运动表现数据。对受试者不同时间点的跳跃高度、加速度、峰值功率、峰值垂直地面反作用力(vertical ground reaction force, v GRF)进行双因素重复测量方差分析(刺激类型×测试时间点)。结果 运动员组,受试者跳跃高度和峰值v GRF的刺激类型×测试时间点交互作用显著,简单效应分析发现a-t DCS后5个时间点的测试数据均显著优于基准值及s-t DCS后(P<0.05);加速度和峰值功率的刺激类型主效应显著。普通大学生组,受试者加速度、峰值功率、峰值v GRF的刺激类型×测试时间点交互作用显著,简单效应分析发现a-t DCS后5个时间点的测试数据均显著优于基准值及s-t DCS后(P<0.05);跳跃高度的刺激类型主效应显著。结论 脑前额叶区a-t DCS能显著改善CMJ完成过程中的多项指标且具有一定的持续性,可以考虑将其作为增强纵跳能力的一种手段。

变频冷水机组在轨道交通的应用能效分析

地铁车站的人流量密集,舒适度要求高,是人们生活中极为重要的公共建筑。本文以深圳地铁12号线的新安公园站、左炮台站、福永站3个站点的空调系统为研究对象,从DeST的负荷模拟、机组性能曲线、运行的实测数据等方面对串联逆流超磁螺杆机组、永磁同步变频螺杆机组、永磁同步变频离心机组、机房和系统进行能效分析。结果表明,应用串联逆流技术的超磁螺杆机组能效较高,5-11月份其主机COP、EERs、TCOP分别达到8.52,7.10,4.05。

The spatio-temporal variation of wintertime subtidal currents in the western Taiwan Strait

A new data set of observations by six cruises of ship-mounted acoustic doppler current profiler（SADCP） and three 40 d long bottom-mounted ADCPs（BADCPs） is employed to reveal the spatiotemporal variability of tidal and subtidal currents in the western Taiwan Strait（TWS） during winter season. The results confirm the existence of intense cotidal lines for M2 tidal current, which is located north of 25°N. In this case, no existence of an amphidromic point can be identified. It is also revealed that the counter-wind current（CWC） can extend through the whole western TWS and even occupy the entire water column during winter monsoon relaxation. However,this CWC is observed to be thoroughly overwhelmed by the downwind China coastal current（CCC） during the two big monsoon bloom events in the winter of 2007, and the CCC consequently extends southward throughout the western TWS instead. Most importantly, the variation of the spatial extent for the CWC and the CCC in the western TWS is found to be well explained by the first two modes of the vector empirical orthogonal function（VEOF） analysis, that is, it is mainly controlled by a wind-driven quasi barotropic current as the first mode and slightly modulated by a relatively weak background current with a first-order baroclinic structure as the second mode.

猪苓中黄嘌呤氧化酶抑制剂的筛选分离及质谱分析

试验以猪苓为研究对象,综合利用遗传算法-BP神经网络数学模型、色谱和质谱等技术,建立快速筛选猪苓中黄嘌呤氧化酶抑制剂的新方法。首先,利用遗传算法-BP神经网络数学模型优化猪苓中麦角甾醇的提取工艺;其次,以黄嘌呤氧化酶为生物靶分子,应用超滤质谱技术,筛选猪苓中潜在的黄嘌呤氧化酶抑制剂,同时,应用分子对接技术验证超滤实验的准确性;最后,以活性筛选为导向,利用高速逆流色谱技术分离猪苓中黄嘌呤氧化酶抑制剂。结果显示:猪苓中麦角甾醇的最佳提取工艺为乙醇体积分数80%、液料比16 mL/g、提取时间1.4 h、提取次数3次,在此条件下,麦角甾醇得率为2.31%;从猪苓中筛选并分离出4个纯度均在90%以上的黄嘌呤氧化酶抑制剂,其抑制效果强弱顺序为猪苓酮A>猪苓酮B>麦角甾-4,6,8(14),22-四烯-3-酮>麦角甾-7,22-二烯-3-酮。该方法快速、灵敏,为猪苓抗痛风药理作用的进一步研究提供了一定的理论基础。