停流流动注射分析同时测定碘离子和亚硝酸根的研究

基于铁(Ⅲ)-硫氰酸根络合物褪色动力学反应,利用流动注射分析停流技术,建立了流动注射动力学分析法同时测定碘离子和亚硝酸根离子的新方法.方法对碘离子的线性范围为2×10^(-5)～1.6×10^(-4)mol/L.对亚硝酸根的线性范围为4×10^(-7)～1×10^(-5)mol/L.应用于合成混合液中碘离子和亚硝酸根的测定,结果满意.

废水中痕量酚的流动注射停流-催化光度法测定

基于在硫酸介质中痕量酚对溴酸钾氧化罗丹明B反应的催化作用 ,建立了测定痕量酚的快速、简便的流动注射停流 催化光度分析的新方法。该方法的线性范围为 0 .6 0～ 4.0 0mg/L ,检出限为 0 1mg/L ,进样频率为 34/h。 11次重复测定的相对标准偏差小于 2 0 %。该法用于废水中酚的测定 ,并与 4 氨基安替比林比色法对照 ,结果满意。

折射＼率对流动注射峰形影响的研究

本文利用折射定律、菲涅耳公式和流体力学原理研究不同浓度乙醇溶液为试剂或载流的单流路体系中，正向流动注射与反向流动注射的信号峰形，对每个正、负峰高度和位置进行解释。给出不同相界面曲面方程，计算不同条件下反射率、反射光和折射光被流通池壁吸收时的径向半径及发生全反射时的径向半径，从理论上计算各种条件下的吸光度。

流动注射分析中样品的分散与载流流速关系的研究

根据串联釜模型,流动注射分析响应曲线的峰高与峰面积、1/4峰高处的峰宽两个因素有关.这两个因素与载流流速的关系分别可以用不同的exp(-q)多项式表示(q是无量纲流速).由于分散度与峰高成反比,分散度随流速的变化关系由此能够很好地得到解释.

高浓度试液流动注射在线稀释方法的研究

将分散－区域采样法用于高浓度试液的流动注射在线稀释，并考察了分散管的长度、管径、两次进样的时间间隔等因素对分散度的影响。方法的精密度优于区域采样法，相对标准偏差小于３％。

铀矿石及浸出液中铝、钙、镁、铁、磷、钼的流动注射光度法分析

作者研究了铀矿石及浸出液中铝、钙、镁、铁、磷、钼的流动注射－光度法分析的测试条件，建立了一次溶矿连续测定多元素的简便可靠的方法。实验采用钻天青S光度法、二甲酚橙光度法、邻菲咯啉光度法、磷钼兰光度法、硫氰酸盐光度法分别测定铝、钙、镁、铁、磷、钼。方法测定范围分别是：铝0．5％～25％，钙0．5％～25％，镁0．5％～20％，铁0．5％～20％，磷0．1％～8％、钼0．02％～5％。对国家一级铀矿石标准物质进行了测定，结果与推荐值吻合，精密度＜5％。该方法适合于厂矿企业的大批量含铀矿石及浸出液中铝、钙、镁、铁、磷、钼的测定。

流动注射在线膜分离预富集在原子光谱中的应用

研究了ＩＤＡＥ（Ｉｍｉｎｏｄｉａｃｅｔｉｃａｃｉｄ／ｅｔｈｙｌｃｅｌｕｌｏｓｅ）膜的在线分离预富集环境水样品中痕量元素的流动注射分析系统。建立了将在线流动注射这一体系与火焰原子吸收、电感耦合等离子体原子发射光谱联用，通过计算机辅助采集数据点，实现天然水样品中痕量重金属元素Ｃｄ，Ｃｏ，Ｃｕ，Ｐｂ，Ｍｎ，Ｖ，Ｎｉ等的在线分离预富集的原子光谱分析方法。本方法的测定速率达到３０次／ｈ，浓集倍数达２０倍。同时我们还考察了体系的检出限、相对标准偏差、加标回收率、膜的动态容量和动态富集性能、富集效率、使用寿命等，取得了令人满意的结果。实验结果表明，流动注射分析（ＦＩＡ）在线分离预富集比起微型柱分离来说，有许多优点，如：分析速度快、自动化程度高、操作简便、不易堵塞、寿命长、重现性好、样品的消耗量少等。ＩＤＡＥＣ膜分离预富集与ＦＩＡ－ＩＣＰ－ＡＥＳ联用的体系，是一种极为方便，高效而且普遍适用，易于推广的测定环境水样品中痕量重金属元素的手段。

流动注射分析仪测量数据的处理

流动注射分析(FIA),是丹麦分析化学家Ruzicka在1974年首次提出的连续分析的新概念,很快引起世界各国分析化学家的兴趣,随之兴起FIA的研究热潮,国内应用的也很广泛。 FIA是建立在以往常规分析基础上,吸取自动分析的优点,简化及减少了繁琐的人工取液、稀释、富集、萃取、加试剂、定容和比色等操作程序,很受化学分析工作者的欢迎,广泛应用于各个领域。 我们使用的Venema G Ⅱ自动综合分析仪,是世界银行从荷兰引进的,可对甜菜的品质因素进行综合检测。可连续进样,一个样品一次进入仪器可同时检测多种元素。进样、定容、加试剂、定量、配比、混合、比色、进入各自的测量室、检测、计算、数据处理、输出、打印、排出废液等,所有过程均由“可编程控制器”控制自动进行。测出的数据精度较高。经几年的使用,总结,我们从实验和理论上进行分析,认为可以在对仪器不作任何改动的情况下,只要对数据采用合理的处理方法,就可以使所获数据的精度和重现性相对得到提高,从而减小离散性。

FIA-双光束分光光度法测定废水中银

本文采用一套流动注射(FIA)-双光束分光光度计装置,研究了试银灵(ρ-DMABR)为显色剂测定银的适宜条件。该法设备简单,灵敏度较普通FIA光度法提高近一倍,进样速度为90～100次/h,相对标准偏差小于0.9%。

铕的光度分析新进展

综述了 2 0世纪 80年代中期以来铕的光度分析方法。对常规光度法 ,流动注射光度法 ,动力学光度法 ,导数光度法和荧光光度法的测定条件及测定范围进行了总结。参考文献 78篇。

CALCULATION FOR SMOKE-PREVENTING AIR CURTAIN IN A HIGH-RISE BUILDING

The effective smoke preventing installation should have the functions such as absolute smoke insulation, going into and coming off the smoke preventing place freely, no confinement of sight. The smoke preventing air curtain is the most effective. Based on the previous researches done by others, the flow field is theoretically analyzed and the calculating method for the smoke preventing air curtain of high rise buildings is inferred by means of mathematics in this paper.

EXPERIMENT ON FLOW CHARACTERISTICS OF SYNTHETIC JET DRIVEN BY PIEZOELECTRIC MEMBRANE

The characteristics of the flowfields of a synthetic jet actuator are experimentally investigated with the slot-nozzle driven by the piezoelectric membrane. The particle image velocimetry （PIV） and the hot-wire anemometer are utilized to measure the flowfields and the velocity profiles of the actuator with different actuating factors. Analytical results show that pairs of counter-rotating vortices are generated near the nozzle. With the development of the synthetic ject, the synthetic jet rapidly spreads in the slot-width direction; while in the slot-length direction, it contracts firstly and slowly spreads. The centerline velocity distribution has a up-down tendency varying with axial distances, and accelerates to its maximum at z/b= 10. The transverse velocity profile across the slot-width is centro-symmetric and self-similar. However, the velocity profiles across the slot-length are saddle-like near the nozzle. It shows that there are two resonance frequencies for the actuator. If the actuator works with the resonance frequency, the vorticity and the velocity of the synthetic jet are higher than those of other frequencies. Compared with the continuous jet, the synthetic jet shows special flow characteristics.

EFFECT OF WALL FUNC TION IN NUMERICAL STUDY ON TURBULENT IMPINGING JET

A low Reynolds number k-ε model is used in the numeri cal study on a circular semi-confined turbulent impinging jet . The result is c ompared with that of the standard k-ε model and a refined k-ε mode l, which re-consi-dered the fluctuating pressure diffusion term in the dissipa tion rate equation (ε-equation) through modeling. It shows that the low Re ynolds number k-ε model and the standard k-ε model yield very poor performance, while the predicting ability of the refined k-ε model is mu ch improved , especially for the turbulent kinetic energy k. So it can be co ncluded that the poor performance of the standard k-ε model is owing to t he incorrect considering the effect of the fluctuating pressure diffusion term r ather than the use of the wall function near the wall just as presumed in the re ference.

Flow and natural convection heat transfer characteristics of non-Newtonian nanofluid flow bounded by two infinite vertical flat plates in presence of magnetic field and thermal radiation using Galerkin method

The main goal of this paper is to investigate natural convective heat transfer and flow characteristics of non-Newtonian nanofluid streaming between two infinite vertical flat plates in the presence of magnetic field and thermal radiation.Initially,a similarity transformation is used to convert momentum and energy conservation equations in partial differential forms into non-linear ordinary differential equations (ODE) applying meaningful boundary conditions.In order to obtain the non-linear ODEs analytically,Galerkin method (GM) is employed.Subsequently,the ODEs are also solved by a reliable numerical solution.In order to test the accuracy,precision and reliability of the analytical method,results of the analytical analysis are compared with the numerical results.With respect to the comparisons,fairly good compatibilities with insignificant errors are observed.Eventually,the impacts of effective parameters including magnetic and radiation parameters and nanofluid volume fraction on the velocity,skin friction coefficient and Nusselt number distributions are comprehensively described.Based on the results,it is revealed that with increasing the role of magnetic force,velocity profile,skin friction coefficient and thermal performance descend.Radiation parameter has insignificant influence on velocity profile while it obviously has augmentative and decreasing effects on skin friction and Nusselt number,respectively.

Research on Mechanism of Airshooting

The composition and ultimate principle of airshooting experimental system were expounded, and the mechanism of airshooting was emphatically discussed on the basis of experiments. The results indicate that the fracture of medium under airshooting resultes from both shock action of air spray and quasi static dilatation of high pressure air. The action of air spray leads to the initial fracture of the wall of borehole and arouses stress wave to propagate in the medium. The quasi static dilatation of high pressure air results in the propagation of initial fractures and produces shear fracture in the medium along the free boundary. Along the direction of minimum burden, the superposition of quasi static and dynamic stress fields can prompt the propagation of cracks. The superposition of the reflected wave, which comes from multiple free surfaces, will result in the fracture of medium also if multiple free boundaries exist.

Numerical Investigation of an Active Jet Control Method for Hypersonic Inlet Restart

A flow control method based on an active jet is developed to restart hypersonic inlets. The dynamic restarting process is numerically reproduced by unsteady Reynolds averaged Navier-Stokes(RANS) modeling to verify the effectiveness and reveal the influence of jet conditions. The active jet improves the inlet unstart status by drawing the high-pressure separation bubble from the internal compression duct and performing a full expansion to alleviate the adverse pressure gradient. Moreover, the favorable pressure gradient in the inlet caused by jet expansion allows for a successful restart after turning off the jet. The influence of the jet momentum ratio is then analyzed to guide the design of the active jet control method and choose the proper momentum ratios. A low jet momentum does not eliminate the high-pressure separation bubble, whereas an excessive jet momentum causes severe momentum loss due to the induced shock. The general rule in restarting the inlet using an active jet is to allow a full jet expansion downstream of the jet slot while avoiding excessive momentum loss upstream and preventing the thick low-speed layer.

The turbulent behavior of novel free triple-impinging jets with large jet spacing by means of particle image velocimetry

A novel reactor that achieves rapid liquid–liquid mixing via free triple-impinging jets(FTIJs) is developed to improve mixing efficiency at unequal flow rates for liquid–liquid reactions. The flow characteristics of FTIJs were investigated using particle image velocimetry(PIV). The instantaneous and mean velocities data at different Reynolds numbers(Re) were analyzed to provide insights into the velocity distributions in FTIJs. The effect of jet spacing on the stagnation points, instantaneous velocity, mean velocity, profiles of the x- and ycomponents of mean velocity, and turbulent kinetic energy(TKE) distributions of FTIJs were investigated at Re = 4100 with a volumetric flow rate ratio of 0.5. The characteristics of the turbulent flows are similar for all jet spacings tested. Two stagnation points are observed, which are independent of jet spacing and are not located in the center of the flow field. However, velocity and TKE distributions are strongly dependent on the jet spacing.Decreasing jet spacing increases the expansion angle and the values of TKE, leading to strong turbulence, improving momentum transfer and mixing efficiency in FTIJs. The present study shows that optimization of the operating parameters is helpful for designing FTIJs.

Analysis of chamber effect on intermittent pulsation

A numerical study was conducted to seek an optimized dimension of jet chamber in the pulsating impinging flow.The flow and heat transfer effect of the pulsation flow through a jet chamber was investigated.The numerical results indicate that heat transfer effective enhances near the stagnation region for the intermittent pulsed flow with jet chamber compared to that without jet chamber.Simulations of the flow through a jet chamber show that the heat transfer rate on the impingement surface is highly dependent on the velocity at the position which is really close to target surface.Examination of the velocity field suggests that the velocity exists a maximum value as the axis distance increases.In addition,the velocity at the jet hole is enlarged by the jet chamber due to the entrainment effect,and the velocity is amplified even greater as the size of the jet chamber becomes bigger.Nevertheless,the velocity declines quickly while the flow axis distance is more than a certain range,leading to poor heat transfer.Thus,intermittent pulsed flow with jet chamber is suggested as a method of improving heat transfer by employing larger dimensions of jet chamber for appropriate jet-to-surface spacing.

Fluid flow characteristics of single inclined circular jet impingement for ultra-fast cooling

The fluid flow characteristics of the single bunch inclined jet impingement were investigated with different jet flow velocities,nozzle diameters,jet angles and jet-to-target distances for ultra-fast cooling technology.The results show that the peak pressure varying significantly from nearly 0.5 to above 13.4 kPa locates at the stagnation point with different jet diameters,and the radius of impact pressure affected zone is small promoted from 46 to 81 mm in transverse direction,and 50 to 91 mm in longitude direction when the jet flow velocity changes from 5 to 20 m/s.However,the fluid flow velocity is relatively smaller near the stagnation point,and increases gradually along the radius outwards,then declines.There is an obvious anisotropic characteristic that the flow velocity component along the jet direction is about twice of the contrary one where the jet anlge is 60°,jet diameter is 5 mm,jet length is 8 mm and jet height is 50 mm.