火力电站冷却氢参数的实时在线监测系统设计

提出了一种能够通过组网、远程采集等技术对火力电站冷却氢参数的实时在线监测系统的设计方案.该方案利用MCGS组态软件进行上位机监控界面的组态,并利用GSM模块实现报警数据的无线传输;以16位单片机MSP430F149作为通用通信模块控制器核心,实现基于RS—485总线模式及Modbus协议的数据采集和通信过程.实际应用表明,该系统能够有效地实现氢参数的实时监测,通信稳定可靠.

基于层次分析-熵值法的氢内燃机异常燃烧风险评估

为了综合评估进气道喷射(PFI)氢内燃机异常燃烧风险,基于层次分析法(AHP)构建了异常燃烧风险系数模型,分别探究喷氢参数对指标层(异常燃烧特征参数)及目标层(异常燃烧风险系数)的影响.结果表明:通过改变喷氢参数,可以使进气道残余氢气量下降33.4%~41.6%,显著降低了回火的可能性.当喷氢角度为30°~45°、喷氢流量为4.36~4.96 kg/h时,缸内混合气均匀性系数较大,有利于组织燃烧,却不能保证炽热区域温度等参数处于较低水准.所构建的异常燃烧风险系数模型能够结合多个特征参数对氢内燃机异常燃烧(早燃及回火)风险进行有效评估.当喷氢角度为45°、喷氢流量为4.96 kg/h时,各项特征参数均处于合理区间,异常燃烧风险系数下降了3.6%~6.8%,降低了异常燃烧的可能性.

Control of repair effect and hydrogen embrittlement risk by parameters optimization for BIEM

Bidirectional electromigration rehabilitation(BIEM)is a novel electrochemical rehabilitation method involving the injection of inhibitors into steel bar surface.The BIEM effect and hydrogen embrittlement(HE)risk depend on the electrochemical parameters(current density and duration)and operating condition(stress level and concrete cover thickness)of reinforced concrete structures.Experiments were performed in this study to investigate the relationships between the aforementioned factors.For a small current density group,a linear relationship was established between electric flux and chloride extraction.For a large current density group,the reasonable current density,stress level,and treatment time were obtained.Finally,the querying method of electrochemical parameters combined with treatment time and current density was proposed.

A non-invasive method for gastrointestinal parameter monitoring

AIM: To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract.METHODS: The authors developed a miniature, multifunctional gastrointestinal monitoring system, which comprises a set of indigestible biotelemetry capsules and a data recorder.The capsule, after ingested by patients, could measure pressure, temperature and pH value in the gastrointestinal tract and transmit the data to the data recorder outside the body through a 434 MHz radio frequency data link. After the capsule passed out from the body, the data saved in the recorder were downloaded to a workstation via a special software for further analysis and comparison.RESULTS: Clinical experiments showed that the biotelemetry capsules could be swallowed by volunteers without any difficulties. The data recorder could receive the radio frequency signals transmitted by the biotelemetry in the body. The biotelemetry capsule could pass out from the body without difficulties. No discomfort was reported by any volunteer during the experiment. In vivo pressure and temperature data were acquired.CONCLUSION: A non-invasive method for monitoring 24-h gastrointestinal parameters was proposed and tested by the authors. The feasibility and functionality of this method are verified by laboratory tests and clinical experiments.

Application of Discrete Lumped Kinetic Modeling on Vacuum Gas Oil Hydrocracking

The kinetic model of vacuum gas oil （VGO） hydrocracking based on discrete lumped approach was investigated, and some improvement was put forward at the same time in this article. A parallel reaction scheme to describe the conver- sion of VGO into products （gases, gasoline, and diesel） proposed by Orochko was used. The different experimental data were analyzed statistically and then the product distribution and kinetic parameters were simulated by available data. Fur- thermore, the kinetic parameters were correlated based on the feed property, reaction temperature, and catalyst activity. An optimization code in Matlab 2011b was written to fine-me these parameters. The model had a favorable ability to predict the product distribution and there was a good agreement between the model predictions and experiment data. Hence, the ki- netic parameters indeed had something to do with feed properties, reaction temperature and catalyst activity.

Study on Hydrocracking of VGO Derived from Kazakhstan-Russian Mixed Crude

This article investigates the influence of the property of VGO derived from the Kazakhstan- Russian mixed crude on the hydrocracking catalyst. The influence of reaction temperature, reaction pressure, space velocity and hydrogen/oil ratio on the distribution and quality of products was analyzed with the optimal process regime determined, when the VGO was hydrocracked in the presence of the FC-16 catalyst.

Study on Kinetics of Iron Oxide Reduction by Hydrogen

Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined. In the experiments, in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe203 to Fe3O4, the reaction temperatures were set between 440 ℃ and 490 ℃. However, in order to distinguish the reduction of Fe304 to FeO from that of FeO to Fe, the reaction temperature in the experiment was set to be greater than 570 ℃. Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.

Electrode properties and phase composition of Ti_(0.5)Ni_(0.25)Al_(0.25) hydrogen storage alloys and theoretical simulation

Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was studied.The phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various temperatures.Electrochemical reaction kinetic parameters were also studied with proper electrochemical techniques.The influence of the secondary corrosion reaction on the anodic linear polarization measurement was also analyzed by theoretical simulation.The results show that,proper ball-milling with nickel powders is beneficial to electrochemical performance.The theoretical simulation proves that,the existence of the side reaction can disturb the measurement of electrochemical reaction kinetic parameters.

Study of large area hydrogenated microcrystalline silicon p-layers for back surface field in crystalline silicon solar cells

A series of hydrogenated microcrystalline silicon （μc-Si：H） p-layers for back surface field in crystalline silicon solar cells were deposited on glass substrates by the developed large area （45 cm×45 cm） plasma enhanced chemical vapour deposition processor operating at 13.56 MHz and various values of source gas trimethylboron （TMB） to H2 flowratio. The influence of deposition parameters on the large area p-layer performance was intensively studied, as well as the thin film uniformity, optical, electrical and structural performances by Raman, PTIR, Ellipsometry, etc. Arrhenius and Tauc plots were used to discuss the μc-Si：H thin film＇s activation energy and the defects state distribution. When amorphous-microcrystalline transition state was obtained, the deposited p-doped μc-Si：H layers showed specific resistance of 38.3 Ω^-1cm1 at the flowratio of 0.66% and high crystallinity of 45%-50% with no further treatment. The effect of source gas flowratio, deposition rate, and source gas partial pressure on μc-Si：H thin film＇s performance was also investigated.

Reversible phase transition of the 1:1 complex between 18-crown-6 and n-propylammonium triiodide

Solid-state structure of the crystalline 1：1 complex [C3H10N（18-crown-6）]＋[I3] （1） between 18-crown-6 and n-propylammonium triiodide has been determined at 293 and 93 K, respectively, showing a change from monoclinic P21/m to monoclinic P21/a. Crystal structural analysis shows that in addition to van der Waals＇ forces, conventional N-H..-O hydrogen bonds are the key interactions. Measurements of unit cell parameters versus temperature show that the values of one of the three axes and the crystal volume change abruptly and remarkably at 220 K, indicating a first-order phase transition. The lack of the mirror plane in the low temperature structure is the most important differences between the two structural forms. Dif- ferential scanning calorimetry （DSC） measurement confirms that I undergoes a reversible phase transition at about 220 K with a thermal hysteresis of 3.5 K. The relatively large latent heat makes 1 a good candidate for phase change materials. The phase transition is accompanied by an anomaly of dielectric constant during heating and cooling process near the phase transition temperature.