Equilibrium on the hydrolysis of boron trifluoride in large amount of water

In order to clarify the equilibrium components in the hydrolysis solution of boron trifluoride(BF_3-H_2O),the BF_3-H_2O was prepared by mixing BF_3-CH_3OH with large amount of water,in which the stoichiometric concentration of BF_3 is less than 0.1 mol/L.Two ionic equilibrium models were proposed to simulate the hydrolysis equilibrium of BF_3 and tested by special acid-base titration technique.The most accurate ion equilibrium constants were determined.The model,which was assumed to have no HF,was proved to be more representative for the real system and used to simulate the hydrolysis equilibrium of BF_3.The simulation suggested that H~+,BF_4~-,BF_3OH~- and H_3BO_3 were the main species in the dilute hydrolysis solution,while BF_2(OH)_2~- and F~- were insignificant species whose concentrations were both in the order of 10~(-4) mol/L magnitude,and BF(OH)_3~- could be omitted because its concentration almost equaled zero.Meanwhile,the equilibrium constant of the overall ionic reaction at 25℃ was obtained as 161.6.     

Mn3+～甲苯非均相体系的氧化反应动力学

The reaction kinetics of the heterogeneous oxidation oftoluene with Mn^3 was studied by considering the effects of disproportionation of Mn^3 in reaction system,a “parallel”modulus was set up.And then the concentration of Mn^3 in disproportionation and the concentration of benzaldehyde in oxidation were respectively determined in turn.the rate constant,order and pseudo-activation energy of the heterogeneous oxidation were obtained by mathematical deduction and the kinetic equation was concluded.In addition,the reaction mechanism was analyzed.It shows that the results are completely consistent with modulus.     

Prediction and setup of phytoplankton statistical model of Qiandaohu Lake

This research considers the mathematical relationship between concentration of Chla and seven environmental factors, i.e. Lake water temperature (T), Secci-depth (SD), pH, DO, CODMn, Total Nitrogen (TN), Total Phosphorus (TP). Stepwise linear regression of 1997 to 1999 monitoring data at each sampling point of Qiandaohu Lake yielded the multi-variate regression models presented in this paper. The concentration of Chla as simulation for the year 2000 by the regression model was similar to the observed value. The suggested mathematical relationship could be used to predict changes in the lakewater environment at any point in time. The results showed that SD, TP and pH were the most significant factors affecting Chla concentration.     

Automatic separation system for marine meiobenthos based on laser-induced fluorescence technology

An automatic system for marine meiobenthos separation was developed by using laser-induced fluorescence technology. Rose Bengal was used as organism dye and the spectrums of Rose Bengal were measured. Laser-induced fluoresce ncesystem was established to detect marine meiobenthos in sediments. Data obtained from experiments were analyzed by using a mathematical model. The results showed that laser-induced fluorescence technology worked well in the system. The system could select the meiobenthos efficiently and precisely.     

Corrosion of carbon steel, zinc and copper by air pollution in Chongqing

This paper presents the research on the atmospheric corrosion rates of carbon steel, zinc and copper in Chongqing, which was a corrosion subprogram of an international project, Regional Air Pollution in Developing Countries. We performed field exposure tests of carbon steel, zinc and copper at an urban site Guanyinqiao and a rural site Tieshanping inChongqing, then used grey relational analysis, based on the database of the whole corrosion project, to determine the order of the effect of environmental factors on corrosion rates of tested metals, and established dose-response functions for these three metals. The results showed that the two crucial agents of acidic environment, SO2 and H , were common factors that contributed most to the corrosion of the tested metals. The established dose-response functions for outdoor carbon steel and zinc are proved applicable to use in Chongqing, but the function for copper needs further modifying. We employed these dose- response functions and general environmental data to elaborate the maps of corrosion rate respectively of carbon steel and zinc by geological information system (GIS) technique which help to identify areas of high corrosion damage risk. An acceptable annual average SO2 level of 21 μg/m3 for carbon steel and that of 61 μg/m3 for zinc are also put forward to control the air pollution impact on atmospheric corrosion in Chongqing urban areas.     

Integration of USEPA WASP model in a GIS platform

The integration of water quality analysis simulation program （WASP） with a geographical information system （GIS） is presented.This integration was undertaken to enhance the data analysis and management ability of the widely used water quality model.Different types of data involved in WASP modeling were converted and integrated into GIS using a database method.The spatial data modeling and analysis capability of GIS were used in the operation of the model.The WASP water quality model was coupled with the environmental fluid dynamics code （EFDC） hydrodynamic model.A case study of the Lower Charles River Basin （Massachusetts,USA） water quality model system was conducted to demonstrate the integration process.The results showed that high efficiency of the data process and powerful function of data analysis could be achieved in the integrated model,which would significantly improve the application of WASP model in water quality management.     

Isobaric vapor-liquid equilibrium for methyldichlorosilane-methyltrichlorosilane-dimethyldichlorosilane system

This paper describes measurement of vapor-liquid equilibrium (VLE) data of methyldichlorosilane-methyltrichlorosilane-dimethyldichlorosilane system and that of the three binary systems at 101.325 kPa with a new pump-ebulliometer. The equilibrium composition of the vapor phase was calculated from pTx by indirect method. The model parameters of the liquid activity coefficient of the Wilson, NRTL, Margules and van Laar equations was corrected by the least square method. The ternary system VLE data were predicted by the Wilson equation, with the calculated boiling points showing good agreement with the experimental data.     

Evaluation and optimization of secondary water supply system renovation

Due to pollution in second water supply system (SWSS),nine renovation alternative plans were proposed and com-prehensive evaluations of different plan based on Analytical Hierarchy Process (AHP) were presented in this paper. Comparisons of advantages and disadvantages among the plans of SWSS renovations provided solid foundation for selecting the most appro-priate plan for engineering projects. In addition,a mathematical model of the optimal combination of renovation plans has been set up and software Lingo was used to solve the model. As a case study,the paper analyzed 15 buildings in Tianjin City. After simulation of the SWSS renovation system,an optimal scheme was obtained,the result of which indicates that 10 out of those 15 buildings need be renovated in priority. The renovation plans selected for each building are the ones ranked higher in the com-prehensive analysis. The analysis revealed that the optimal scheme,compared with two other randomly calculated ones,increased the percentage of service population by 19.6% and 13.6% respectively,which significantly improved social and economical benefits.     

不锈钢氩氧脱碳精炼过程的物理和数学模型

The available studies in the literature on physical and mathematical modeling of the argon-oxygen decarburization(AOD) process of stainless ssteel have briefly been reviewed.The latest advances made by the author with his research group have been summarized.Water modeling was used to investigate the fluid flow and mixing characteristics in the bath of an 18t AOD vessel,as well as the “back-attack” action of gas jfets and its effects on the erosion and wear of the refractory lining,with sufficiently full kinematic similarity.The non-rotating and rotating gas jets blown through two annular tuyeres,respectively of straight-tube and spiral-flat tube type.Were employed in the experiments.The geometric similarity ratio between the model and its prototype(including the straighttube type tuyeres)was 1:3 ,The influences of the gas flow rate,the angle included between the two tuyeres and other operating parameters,and the suitability of the spiral tuyere as a practical application,were examined.These latest studies have clearly and successfully brought to light the fluid flow and mixing characteristics in the bath and the overall features of the back-attack phenomena of gas jfets during the blowing.nd have offered a better understanding of the refining process.Besides,mathematical modeling for the refining process of stainless steel was carried out and a new mathematical model of the process was proposed and developed.The model performs the rate calculations of the refining and the mass and heat balances of the system.Also,the effects of the operating factors,including adding the salg materials.crop ends,and scrap,and alloy agents;the non-isothermal conditions;the changes in the amounts of metal and slag materials,crop ends,and scrap,and alloy agents;the non-isothermal conditions;the changes in the amounts of metal and slag during the refining;and other factors were all considered.The model was used to deal with and analyze the austenitic stainless steel making (including ultra-low carbon steel) and was tested on data of 32 heats obtained in producing 304 grade steel in an 18t AOD vessel.The changes in the bath compostion and temperature during the refining process with time can be accurately predicted using this model.The model can provide some very useful information and a reliable basis for optimizing the process practice of the refining of stainless steel and control of the process in real-time and online.     

Application of Dual Throttling Air-Conditioning System to Explosion-Proof Frequency Converter

An explosion-proof dual throttling air-conditioning system was put forward to solve the heat dissipation and internal dewing problems of explosion-proof frequency converter in the underground coal mine. This study investigated the feasibility and benefits of explosion-proof dual throttling cooling and dehumidification air-conditioning system applied to the explosion-proof frequency converter. The physical model of dual throttling air-conditioning system was established and its performance parameter was described by mathematical method. The design calculation of the system has also been done. The experimental result showed that the system reached the steady state at the refrigeration mode after running 45 min, and the maximum internal temperature of the flame-proof cavity was 31.0 ℃. The system reached the steady state at the dehumidification mode after running 37 min. The maximum internal relative humidity and temperature of the flame-proof cavity were 33.4% and 36.3 ℃, respectively. Therefore, the proposed system had excellent ability of heat dissipation and avoided internal dewing. Compared with water cooling system, it was more energy-saving and economical. The airflow field of dual throttling air-conditioning system was also studied by CFD simulation. It was found that the result of CFD numerical simulation was highly consistent with the experimental data.     

Modeling personalized head-related impulse response using support vector regression

A new customization approach based on support vector regression (SVR) is proposed to obtain individual headrelated
impulse response (HRIR) without complex measurement and special equipment. Principal component analysis (PCA) is
first applied to obtain a few principal components and corresponding weight vectors correlated with individual anthropometric
parameters. Then the weight vectors act as output of the nonlinear regression model. Some measured anthropometric
parameters are selected as input of the model according to the correlation coefficients between the parameters and the weight
vectors. After the regression model is learned from the training data, the individual HRIR can be predicted based on the
measured anthropometric parameters. Compared with a back-propagation neural network (BPNN) for nonlinear regression,
better generalization and prediction performance for small training samples can be obtained using the proposed PCA-SVR
algorithm.     

Rheology-based facial animation realistic face model

This paper presents a rheology-based approach to animate realistic face model. The dynamic and biorheological
characteristics of the force member (muscles) and stressed member (face) are considered. The stressed face can be modeled
as viscoelastic bodies with the Hooke bodies and Newton bodies connected in a composite series-parallel manner. Then, the
stress-strain relationship is derived, and the constitutive equations established. Using these constitutive equations, the face
model can be animated with the force generated by muscles. Experimental results show that this method can realistically
simulate the mechanical properties and motion characteristics of human face, and performance of this method is satisfactory.     

Phytoremediation potential of Cyperus rotundus for diesel-contaminated wetland

Oil spills may considerably damage sensitive coastal wetlands. The phytoremediation potential and restoration of a dominant coastal marsh plant, Cyperus rotundus, for diesel pollutant and its phytoremediation effectiveness were investigated in this open-air pot experiment. Cyperus rotundus was transplanted into soil contaminated with diesel at concentrations of 1 000, 5 000, 10 000, 15 000, 20 000 mg/kg. In order to better elucidate the biochemical and physiological responses to diesel pollutants, activity of the antioxidant enzymes peroxidase （POD）, catalase （CAT） and ascorbic acid oxidase （AAO） were determined in the plant tissue after 50 d treatment at the levels mentioned above. The results showed that CAT and AAO of stem and leaf exhibited peak enzyme activities on 15 000 mg/kg soil and 10 000 mg/kg soil respectively, and declined at higher concentrations. Additionally, the increment of biomass and the content of soluble protein, as well as chlorophyll content were affected by diesel. The highest restoration effectiveness appeared at the level of 5 000 mg/kg. Collectively, Cyperus rotundus is a potential plant which can be used for restoring the diesel-contaminated soil.     

Exposure of university students to polycyclic aromatic hydrocarbons measured from urinary monohydroxy metabolites

Internal exposure of university students to polycyclic aromatic hydrocarbons(PAHs)was assessed through urinary PAHs metabolites. Eight monohydroxylated PAHs(OH-PAHs)were detected with high performance liquid chromatography (HPLC). The detectable frequencies were 59%-100% for different analytes. Major components in the subjects‘ urine were 2-hydroxynaphthalene(2-OHNap, 0.60 μg/mmol creatinine), followed by hydroxyphenanthrene(ΣOH-Phe, 0.38 μg/mmol cre-atinine)and 2-hydroxyfluorene(2-OHFlu, 0.25 μg/mmol creatinine). Excretion of 1-hydroxypyrene(1-OHPyr, 0.08 μg/mmol creatinine)was almost one order of magnitude lower than the 2-OHNap level in the urine samples. Phenanthrene can be metabolized to five monohydroxy metabolites in human urine. In the present study, 1-or 9-hydroxyphenanthrene(1-or9-OHPhe)was the dominant component(79%), followed by 2-+3-OHPhe(18%)and 4-OHPhe(3%). The study indicates that 1-OHPyr may not be a good marker for total PAHs exposure, and monitoring of 2-OHNap, 2-OHFlu, 1-or 9-OHPhe and 1-OHPyr as multiple biomarkers are more suitable than only using 1-OHPyr. The levels of OH-PAHs detected in urines of students living in Shanghai are higher those of people in other countries or regions. The concentrations of urine OH-PAHs are directly related to the exposure to PAHs in the environment, indicating that Shanghai residents are at high health risk.     

Riemann problem of a Chapman-Jouguet combustion model for pressure-gradient system

In this paper,the Riemann problem of a Chapman-Jouguet combustion model for the pressure-gradient equations is considered.By analyzing in phase space,existence and uniqueness of the solution to the Riemann problem are obtained constructively under the global entropy conditions.     

Preparation of the polysulfonamide/titania composites

A series of polysulfonamide （PSA）/TiO 2 modifier nano-composite films were successfully prepared by in-situ polymerization at a low temperature based on 4, 4-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N, N-dimethylacetamide （DMAc）. It was shown that the nano particles were well dispersed in the polymer substrate. Mean-while, PSA/TiO 2 /modifier composites exhibited good UV-resistant properties and mechanical properties. In addition, the composites’ heat stability improved. These prepared composites are promising in preparing spinning solution and might have potential application in heat-resistant fiber.     

Extraction of color-intensity feature towards image authentication

A color-intensity feature extraction method is proposed aimed at supplementing conventional image hashing algorithms that only consider intensity of the image. An image is mapped to a set of blocks represented by their dominant colors and average intensities. The dominant color is defined by hue and saturation with the hue value adjusted to make the principal colors more uniformly distributed. The average intensity is extracted from the Y component in the YCbCr space. By quantizing the color and intensity components, a feature vector is formed in a cylindrical coordinate system for each image block, which may be used to generate an intermediate hash. Euclidean distance is modified and a similarity metric introduced to measure the degree of similarity between images in terms of the color-intensity features. This is used to validate effectiveness of the proposed feature vector. Experiments show that the color-intensity feature is robust to normal image processing while sensitive to malicious alteration, in particular, color modification.     

Determination of the volatile fraction of coal tar

The coal tar was qualitative and quantitative anMyzed by gas chromatography （GC） method. 74 components were identified exactly by gas chromatographY-mass spectrometry （GC-MS）. 31 components （37%） were quantitatively analyzed by gas chromatography-flame ionization detector （GC-FID）. The linearity, accuracy, precision, limit of detection （LOD） and limit of quantitative （LOQ） determination were inspected. The scope of quantitative analysis by CC was discussed. The experimental results of thermogravimetric analysis （TGA） proved that GC quantitative analysis of the coal tar was reliable.     

Microstructure and mechanical properties analysis of β-tricalcium phosphate/carbon nanotubes scaffold based on rapid prototyping

β-TCP ceramic scaffolds were fabricated with selective laser sintering(SLS)in this work. Carbon nanotubes(CNTs)were mixed with porous β-TCP matrix to enhance the mechanical performance of the bone tissue engineering scaffolds. Scaffold reconstruction and microstructure analysis were fulfilled based on micro-computed tomography(Micro-CT)scanning data.Results show that the strength of scaffold mixed with 0.2% CNTs reaches 0.819 MPa which has been improved by 85.7% compared with that without CNTs. Micro-CT analysis shows that the scaffold has a good interconnectivity, and pore size mainly distributes in the two regions of 60-340 μm and 500 620 μm.     

Planetary scroll surface polishing method for aluminum wheel hub

Instead of manual polishing work for aluminum wheel hub （hub） surface, a new planetary scroll surface polishing method based on the rotation and revolution of hub in abrasives is presented in this paper. Since conventional barrel rotation polishing mode is unsatisfactory, shorter polishing period and lower energy consumption are expected. The surface polishing mechanism of the proposed method is ghen introduced. The influence of cutting velocity, cutting angle, abrasive on surface polishing quality and efficiency, as well as the correlation of the revolution velocity and the rotation velocity of hub are discussed. Experimental results show that high surface polishing quality and efficiency can be achieved with the new polishing method implying that a dustless clean working environment is realized.