Development of an amperometric flow injection immunoanalysis system for the determination of the herbicide 2,4-dichlorophenoxyacetic acid in water

An amperometric flow injection immunoanalysis (FIIA) system based on an immunoreactor with immobilized biocomponents on a silica surface has been developed for the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). In the antigen coating mode the hapten was immobilized and monoclonal primary antibody against 2,4-D together with alkaline phosphatase (AP)-labelled secondary antibody were used as sensing elements in a titration assay. In the antibody coating mode a biotinylated monoclonal antibody was immobilized on the surface of the immunoreactor and a 2,4-D-AP-conjugate was used for detection. For electrochemical measurements p-aminophenol enzymatically generated from p-aminophenyl phosphate was oxidized at a carbon working electrode at +150 mV versus Ag/AgCl. The system enabled the determination of 2,4-D in drinking water samples in the range from 0.2 to 70 micrograms/l. The whole system was computer controlled with a measuring time of 12 min for one determination.     

Using a precision-metered injection system to minimize dental injection anxiety

In this study, 90% of dental patients reported being at least mildly anxious about receiving dental injections. A new precision-metered injection system has been developed that can greatly increase the probability of painless injections of local anesthetic. Surveys were administered to patients to quantify their fears of dental injections and to measure the desensitization effect of using the new injection system. According to survey results, fear levels decreased significantly when the new technology was used.     

基于人工神经网络的粉末注射成形智能化控制仿真系统

基于数值模拟和人工神经网络模型以及对智能控制工艺过程的适当简化,为拉伸样模型的注射过程建立了一套智能化控制仿真系统.研究表明,该系统能够根据样品对性能的要求(如密度分布),自动进行注射工艺参数的优化.采用优化后的注射工艺参数重新进行注射过程模拟计算后,发现注射坯密度分布的均匀性较调整前有显著提高,基本符合预期的密度要求,证明智能化控制仿真系统可行.     

Flow injection analysis system for the supervision of industrial chromatographic downstream processing in biotechnology

Sugar beet molasses is a natural resource for various products used in daily life, ranging from sucrose to amino acids for pharmaceutical industry. The separation of molasses into these high value components is performed on a large scale by ion exchange/exclusion chromatography. A biosensor system was set up for the "in time" analysis of serine and sucrose during molasses desugarisation. D-Serine was analysed with the multi-enzyme system D-serine dehydratase/lactic dehydrogenase and photometric detection of the NADH consumed. Sucrose was determined with invertase/mutarotase/glucose oxidase and the oxygen consumed was monitored amperometrically. An analysis could be performed within 2-5 min by directly injecting samples from the chromatographic process into the flow injection analysis system. The determination range for the sucrose analysis was 0-2.5 gl-1 and for the analysis of D-serine 0-0.5 gl-1. The standard deviation for the measurement of D-serine was 1.7%.     

Flow regimes in submerged gas injection

The behavior of gas discharging into a liquid has been investigated in the labora-tory and in plant. The laboratory work has involved the injection of different gases from a submerged, horizontal tuyere into water, zinc-chloride solution, and a mercury bath. High speed cinematography and pressure measurements in the tuyere have been carried out to characterize the flow regimes. In the case of the mercury bath, a novel “half-tuyere” has been developed to permit visual observation of the gas. In this way, two regimes of flow, bubbling and steady jetting, have been delineated as a function of the modified Froude number and the ratio of gas to liquid densities. Pressure measurements at the tuyere tip have been correlated to the different stages of bubble growth in the bubbling regime, and can be used to distinguish one flow regime from the other. The measured bubble frequency and volume correspond reasonably well to predictions of a simple model of bubble growth under conditions of constant flow. The forward penetration of the jet centerline from the tuyere tip has been measured and found to depend both onN _Fr′ andρg/ρl. In the industrial tests, pressure taps have been installed in the tuyeres of a nickel converter to monitor the pressure wave of the jets under normal, low pressure blowing operations. The measurements show that the converter jets operate in the bubbling mode with a bubble frequency of 10 to 12 s⁻¹, similar to a gas jet in mercury. Tests involving higher pressure injection indicate that the steady jetting, or underexpanded, regime obtains at pressures of about 340 kPa (50 psi). Based on equivalent experiments in the laboratory, it is clear that low pressure blowing has the disadvantage of poor penetration of air into the bath so that the jets rise close to the back wall and locally accelerate refractory wear. Moreover between the formation of successive bubbles, the bath washes against the tuyere mouth and contributes to accretion formation. This necessitates periodic punching of the tuyeres which also contributes to refractory wear at the tuyere line. The use of high pressure injection to achieve steady jetting conditions, as currently practiced in the new bottom blown steelmaking processes, should be considered to solve these prob-lems, and possibly usher in a new generation of nonferrous converters.     

利用Silnikov定理构造混沌系统

利用Silnikov定理构造了一类新的三维二次多项式混沌系统,该系统只具有一个平衡点.理论分析表明该系统具有Smale马蹄意义的混沌,计算机仿真实例显示系统的Smale马蹄具有吸引性.利用该方法还可以构造其他的三维二次多项式混沌系统.     

流动注射分光光度法测定废水中砷

建立了测定砷(Ⅲ)的流动注射光度分析法。在0.5 mol/L的硫酸介质中,溴酸钾的强氧化性将砷(Ⅲ)氧化成砷(Ⅴ),剩余的溴酸钾与碘化钾反应生成单质碘,利用碘与淀粉形成蓝色络合物,间接测定微量砷(Ⅲ)。方法的线性范围为0.04~1.20μg/mL,检出限为6.2×10-3μg/mL(3倍噪音);除IO3,IO4,Cr2O27-等强氧化性阴离子外,其余阴离子以及大量常见阳离子对砷的测定没有干扰。对质量浓度为0.30μg/mL的As(Ⅲ)标准溶液连续进样11次测定,相对标准偏差为1.8%。该方法用于废水中砷的     

Optimal Barrage Design based on Subsurface Flow Considerations

A barrage, a structure across a river to divert flow into a man-made channel, is designed to satisfy surface and subsurface flow considerations. There is, however, no procedure to fix the basic barrage parameters, which are depth of sheet piles/cutoffs and the length and thickness of floor, in a cost-effective manner. A method for minimizing the cost of a barrage using an optimization technique is presented in this paper. The applicability of the approach has been illustrated with two examples indicating it’s suitability to evolve a cost-effective design. A parametric analysis has also been carried out to gain insight into the effects of various parameters on the optimal design barrage.     

Flow injection photometric determination of zinc and copper with zincon based on the variation of the stability of the complexes with pH

PURPOSE: The objective of this study was to determine the maximally tolerable doses (MTDs) of vinorelbine (VNR) and gemcitabine (GEM) when combined with a fixed dose of cisplatin (CDDP). PATIENTS AND METHODS: Chemotherapy-naive patients with stage IIIB-IV non-small-cell lung cancer (NSCLC) received a fixed dose of CDDP (50 mg/m2) and escalating doses of VNR (starting from 20 mg/m2) and GEM (starting from 800 mg/m2) on days 1 and 8, every three weeks. The single escalation of GEM alone, by 200 mg/m2 at each step, was initially planned up to a dose of 1,200 mg/m2, to be followed by increments of the VNR dose of 5 mg/m2 at each step. RESULTS: Thirty-one patients were enrolled at five different dose levels. The escalation was stopped at level 4 (GEM 1,200 mg/m2 and VNR 25 mg/m2) since two of six patients of this cohort showed dose-limiting neutropenia at treatment cycle 1. Two different dose levels, GEM 1,200 mg/m2 + VNR 20 mg/m2, and GEM 1,000 mg/m2 + VNR 25 mg/m2 were fairly well tolerated. No treatment-related deaths occurred. Neutropenia was the main toxic effect, occurring in 76% of the total of 116 cycles delivered, and in 24% of them was of grades 3 or 4. A total of eight patients (26%) experienced grade 4 neutropenia lasting more than seven days; in five of them it occurred in the first course. Neutropenic fever was observed in four cases. Grade 4 thrombocytopenia occurred in only two patients. Non-hematologic toxicity was a minor problem in all patients but was never dose-limiting. No complete responses were obtained, but sixteen out of 31 (52%) patients achieved partial responses. The median duration of response was 20 (range 6-56+) weeks, while at a nine-month median follow-up, the median survival time has not yet been reached. To date, 18 patients are still alive. The one-year projected survival for all patients was 51%. CONCLUSIONS: Our results show that CDDP, VNR and GEM can be safely given together without substantial reductions in their individual dose intensities. In our opinion, the dose level of GEM 1,000 mg/m2 + VNR 25 mg/m2 given in combination with CDDP 50 mg/m2 on days 1 and 8 of a three-week cycle can be recommended for phase II trials, since it provides a better balance in dose intensity of GEM and VNR. A phase II randomised study is underway to establish the activity of this new regimen (at the above-cited dose level) in chemo-naive NSCLC patients.     

A study on measurement of gas-liquid interfacial area in a dispersed gas injection system

The gas-liquid interfacial area in a dispersed gas injection system was estimated by a chemical method and measured directly by an electroresistivity probe method. In the chemical method, the gas-liquid interfacial area was obtained by plotting CO₂ absorption rate in 0.1 mol/L KOH solution based on the gas absorption theory. In the electroresistivity probe method, local gas holdup, bubble rising velocity, and local bubble diameter were measured in the same solution into which air was injected upwardly. Overall mean values of gas holdup and bubble diameter in the vessel were obtained by means of statistical treatments. The specific interfacial area was calculated from these data. Measurements were done in a cylindrical water vessel under different conditions of gas flow rate and nozzle diameter. The measured values of the specific interfacial area by the electroresistivity probe method were compared with those by the chemical method and showed good agreement. H.K. PARK, formerly Graduate Student, Seoul National University.     

Flow injection cytometry: a new approach for sample and solution handling in flow cytometry

A prototype instrument for sample and solution handling in flow cytometry has been constructed. The system is modular and allows the control of any combination of up to 4 pumps, 2 selection valves, and 2 injection valves. These devices are controlled by a computer using TTL-logic. The flow injection instrument is interfaced to the flow cytometer via a 6-port injection valve, thereby facilitating virtually any flow pattern to be implemented without affecting the fluidics of the cytometer. Salient features of the instrument are accurate control of the volume of injected sample and reagent, reproducible timing, and controlled mixing conditions. Results from model experiments of on-line staining of trout erythrocytes with different concentrations of 4',6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI) are shown. Possible ways to improve the performance and utility of the instrument are also discussed.     

流动注射电化学发光分析法测定煤灰中微量铀

采用恒电位电解技术,使不具发光活性的铀(Ⅵ)通过自制的流通式碳电解池后,在-0.70 V(vs.Ag/AgCl)电位下在线还原为铀(Ⅲ),铀(Ⅲ)与鲁米诺在碱性条件下产生化学发光,从而建立了铀(Ⅵ)的流动注射电化学发光分析法。方法的线性范围为1.0×10-9~1.0×10-5g/mL,检出限为2×10-10g/mL,对1.0×10-7g/mL铀(Ⅵ)进行13次测定,得到相对标准偏差为2.5%。该方法用于煤灰中微量铀(Ⅵ)的测定,结果良好。     

单喷颗粒镁脱硫与镁基复合喷吹脱硫喷吹系统的区别

单喷颗粒镁脱硫和镁基铁水脱硫是最常见的铁水脱硫技术,对单喷颗粒镁脱硫与镁基复合喷吹脱硫喷吹系统进行了比较,主要区别在于:单喷镁脱硫系统要求的镁颗粒较大,球形度好,采用机械给料的方式精确给料,料罐容积小,利于实现设备的小型化,但是喷枪需要设置气化室,结构复杂;复合喷吹铁水脱硫通过调节动力学参数来调节镁粉喷吹速率。     

基于流量信号的液压系统故障诊断

以流量信号作为特征信息进行液压故障诊断,分析了液压系统中出现流量异常时的主要表现及产生原因,基于流量信号与液压系统工况之间关系的分析及CBG 2040型齿轮泵的4种故障的实验研究,指出:流量信号也是状态信息的丰富载体,利用流量信号来监测液压系统的状态及进行故障诊断是可行的、有效的.     

一种非接触式实时视线追踪系统的设计

为方便残疾人和老年人使用计算机进行信息交互,设计了一种非接触式低成本视线追踪系统.系统设计了一种双环形红外光源,通过交替照射用户脸部,用单CCD摄像机得到\     

Determination of human leg blood flow: a thermodilution technique based on femoral venous bolus injection

1. A thermodilution method was developed for the determination of human leg blood flow. The method is based on bolus injection of an indicator distally into the femoral vein, at room temperature, and recording of the dilution curve in the same vessel at the level of the inguinal ligament. The blood flow was computed automatically with two thermistors and an integrator. 2. The leg blood flow determined by this method at rest and during exercise at work loads of 50, 100 and 150 W in six healthy subjects was found to agree closely with measurements by an intraarterial indicator-dilution technique. A linear relationship was found between leg blood flow and work. The reproducibility of the blood flow determinations, expressed as the coefficient of variation for a single determination, was 12.9 at rest and 5.3 or less during exercise. 3. The method was used in two patients with occlusive arterial disease of the leg. Extremely low leg blood flows were found in these patients when they were forced to interrupt the exercise by severe calf pain     

Flow and fracture of bimaterial systems based on aluminum alloys

The effect of property mismatches on constrained plastic flow in aluminum alloys was investigatedvia both finite element modeling (FEM) and experimentation. Double-notched tension tests on monolithic aluminum alloys and notched trilayer laminates, consisting of the aluminum alloy and a discontinuously reinforced aluminum material, were used to experimentally study the degree of constraint developed in aluminum alloys for use in bimaterial systems. Constraint levels in bimaterial systems were found to be affected by mismatches in elastic modulus and strength. The trends observed in the development of constrained plastic flow in these studies were rationalized based upon the effects of stress triaxiality on the flow and fracture behavior of the various aluminum alloys investigated.     

喷煤系统的节能措施

结合国内外喷煤新技术，分析了与喷煤系统本身有关的几个节能问题，提出了节能的具体措施；选用新型磨煤机；简化制粉系统；喷吹混合煤，喷吹粒煤，浓相输送煤粉等。