bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowing Place in International Landscape Architectural Practice
Authors: Zhang Yun , Du Ming
Published: August 2012

This paper investigates ways of knowing a particular place in landscape architectural practice across cultures. The approach of landscape architecture to place suggests a primary goal to look after places’ characteristics. Therefore, landscape architects have developed ways to gain understanding of place and its natural and cultural environment. A case study of the planning and design of the Li Lake area in China where Australian landscape architects played key roles showed their genuine engagement with place through intensive site investigations and close interaction with local governmental clients. It also showed their difficulties in gaining implicit knowledge of this area, because their early and direct interaction with local landscape architects and communities was restricted by the commissioning process.
Bond of Corroded Reinforcement and Concrete under Repeated Loading
Authors: Dai Xiao Dong , Kou Xin Jian , Wen Shi Chen , Liu Jin
Published: August 2012

Bond of corroded reinforcement and concrete under repeated loading was investigated experimentally. An electrolyte corrosion technique was used to accelerate reinforcement corrosion. The results of the experiment indicate that: corrosion of reinforcement is the significant factor affecting the bond, with the increasing number of loading, the peak bond stress and area of hysteretic curve decrease gradually.
Durability of the Airfield Pavement Concrete on the Qinghai-Tibet Plateau
Authors: Cen Guo Ping , Liu Qing Tao , Hong Gang , Wang Jin Hua
Published: August 2012

This paper analysed the unique climatic characteristics of Qinghai-Tibet plateau and the durability requirements of airfield pavement concrete, improved the frost resistance, impermeability and abrasion resistance of pavement concrete by mixing air-entraining and water-reducing admixtures. The relations of content of the air-entraining admixture, strength and frost resistance of concrete were tested systematically in laboratory, the appropriate air content was put forward. The tests shown that the frost resistance, impermeability and abrasion resistance fulfilled the requirements of the plateau airfield pavement. In the field of Yushu Airfield in Qinghai, it studied the raw materials selecting, control of air content and construction technics, ensured the durability of the pavement concrete and gained well effect.
Elasticity Stability Analysis of Cable Stayed Arch Bridge in Plane
Authors: Yan Xiao Xin , Yu Shu Fang , Zhao Liang Hua , Li Zong Ming
Published: August 2012

Cable stayed arch bridge is a hybrid arch system which is different with architectural cable-arch and stretch-draw prestressed tendon out of arch. In this article, by comparing the plane models of cable stayed arch bridge and common arch bridge and calculating, we analysed cable stayed arch elastic stability in plane of different rise-span ratios, boundary conditions, load cases.
Nonstationary Probabilistic Seismic Response Analysis of Nonlinear Soil Profile under Bidirectional Dynamic Loading
Authors: Pan Xiao Dong , Zhong Jia En , He Chao Chao
Published: August 2012

In this paper, according to the characteristics of near-fault earthquakes, combined with the strong ground motion attenuation law in China, the nonstationary power spectrum of bidirectional ground motion input is obtained through random vibration analysis. By introducing the pseudo excitation algorithm, the evolutionary power spectral density (PSD) of acceleration at the engineering bedrock is handled as the nonstationary pseudo input, and the Hardin-Drnevich hyperbolic model is utilized to take into account the nonlinearity of soil layer. On this basis, finite element method in the time domain and frequency domain are used for seismic response analysis of soil profile. Values including various time-varying power spectral density of the dynamic response, time varying RMS and time-dependent reliability at different threshold can be obtained by calculating, which provides a basis for the analysis of the foundation dynamic reliability assessment.
Optimal Design for the Maximum Load of Three-Point Bending Concrete Beam Based on the Analyzing of Critical Crack-Mouth Opening Displacement
Authors: Wang Xue Qin , Wang Lin
Published: August 2012

An optimal design method for the maximum load of three-point bending concrete beam is proposed in this study. The statistics model is built according to the theory of GR resistance curve. With the help of least square method and Matlab® computing platform, the optimal design results are very similar of the experimental results, and thus a new criterion for unstable fracture in crack extension resistance curve theories is constructed. It can able to monitor safety and stability of specimens in engineering practice at any time.
Bearing Capacity Analysis on Improved Slotted End Plate Connections
Authors: Wan Hong , Peng Yi Liang , Yang Jun Fen , Qiang Ruo Hui
Published: August 2012

Full-scale of U-type and grooved-type slotted end plate (SEP) connections are tested to determine their failure modes and damage mechanisms under ultimate loading. Simulate on mechanical behaviors of U-type and grooved-type SEP connections under compression using finite element software ANSYS based on the experimental research. Obtain load-vertical displacement curves of the SEP connections, and compare with the experimental results to determine the validity of the model. On this basis, this paper provide the improved SEP connections, and contrast with the U-type and grooved-type SEP connections. The results indicate that finite element results are in good agreement with experimental data. Difference of the ultimate load between the test specimen and finite element model is less than 10%. The finite element can simulate mechanical behaviors of the SEP connections better. The ultimate bearing capacity of the UC-type SEP connected joints is significantly higher than the U-type and grooved-type, which shows the improved SEP Connections is reasonable and effective. SEP is the main factor of the U-type and grooved-type SEP Connections’ ultimate load, tube is controlling factor of the UC-type SEP connected joints.
Numerical Investigation of Stress Concentration Phenomenon in Piled Embankment under Moving Train Loads
Authors: Thach Pham Ngoc , Kong Gang Qiang
Published: August 2012

A numerical study is performed to investigate the stress concentration phenomenon in a piled embankment during high-speed train passage. In the numerical simulation, the loading of a moving train is first represented in the model as a series of time-varying equivalent concentrated forces vertically acting on the ballast surface, and the explicit finite element method (FEM) is then used to analyze the ballast-embankment-ground system subjected to the equivalent forces. The study shows that owing to the very high stiffness of the piles relative to the soft soil, a majority of the wave energy, which is generated by the passage of wheel axles, is concentrated to the improving piles and transferred down to the stiff soil stratum. By this stress concentration phenomenon, the soft soil surrounding the piles is subjected to less stress, and thus preventing undesirable dynamic effects that could be induced in the soft soil.
Experimental Research on Shock Wave in Water of Underwater Drilling Blasting
Authors: Si Jian Feng , Zhong Dong Wang , Li Lin Na
Published: August 2012

Based on theoretical research, waveform curve of shock wave and the pressure data of underwater group of satchel charges were measured by doing the monitoring test in the waterway dredging project of the second-phase construction in Gulei Xiamen. Characteristics and the law of its propagation of shock wave in water produced by the explosion were analyzed, the conclusion which the single dosage is 110 ~ 500kg while the total dosage is 730 ~ 4710kg and the blasting distance is from 74.5 to 220m was given. Semi-theory-semi-experienced formula of the shock wave on this condition was verified. Much valuable experience has been accumulated for the further research.
The Forecasting for Artificial Frozen Soil Temperature Field Based on Support Vector Machines Method
Authors: Zhang Shi Yin , Chen Jun Hao , Mao Fen
Published: August 2012

The level of soil freezing temperature has a direct impact on the time of formatting effective frozen wall and the value of freeze wall thickness, and it has a certain relationship with the soil composition, moisture content, density, liquid limit moisture content, pressure and saltness .For the feature of less measured sample of new mines, using the theory that is based on structural risk minimization and the method of small sample study-Support Vector Machine Algorithm, the support vector machine computation model of artificial frozen soil temperature has been established. Using support vector machines of different kernel functions to analyze the frozen temperature calculation of artificial freezing soil, the kernel function that is fit for the frozen temperature calculation of artificial has been determined. The results of support vector machine calculation model shows that this method is an effective method, it has provide a new approach for the frozen temperature calculation of artificial freezing soil.
Pore Size Dependence of Compressive Behavior and Energy Absorption Properties of Porous Copper
Authors: Hao Gang Ling , Xu Qiao Ping , Han Fu Sheng
Published: August 2012

Porous copper with an open-cellular structure was prepared basing on space-holder method. Depending on the volume fraction and size of the space holding particle, the porosity can be varied in a wide range of 40-85%, and the pore size can be tailored from micron to millimeter in order. The effects of pore size on compressive behavior and energy absorption properties were investigated by quasi-static compression measurement. The results showed that the pore size shows a significant effect on compressive behavior and energy absorption properties. The compressive stress-strain curves were increased with increasing the pore size. The energy absorption capacity and energy absorption efficiency were greatly improved at the same strain, when the pore sizes transferred from micron to millimeter in order, indicating a more desirable energy absorption property of larger pore size.
Simulation Analysis of Springback for Lead Frame Copper Alloy
Authors: Su Juan Hua , Ren Feng Zhang , Yang Ze
Published: August 2012

The bending performance of lead frame materials is a very important in improving the quality of lead frame alloys and meeting the needs of high performance integrated circuit. The sringback amount of curvature variation of CuFeP , CuCrZrMg , CuNiSi and CuCrSnZn alloy are researched by numerical simulation. Bending model is built by 3D modeling software, and the necessary post-processing is carried out. The bending springback amount △K of the four kinds of copper alloy materials are calculated out. The results show that the sringback amount of curvature variation of four copper alloys at the same condition from large to small in turn is CuCrZrMg, CuNiSi, CuFeP, CuCrSnZn. Smaller the minimum relatively bending radius of copper alloy used in lead frame, less the springback amount and better the forming performance.
Improving the Properties of Magnetic Bearing Shaft Material by HVOF Coating of WC-Metal Powder and Laser Heat Treatment
Authors: Cho T.Y. , Joo Y.K. , Yoon J. H. , Chun H. G. , Zhang S.H.
Published: August 2012

Abstract. Micron-sized WC-metal (WC-0.6%C-21%Cr-6%Ni) powder was coated onto the substrate of magnetic bearing shaft material Inconel718 (substrate or In718) using JK3500 HVOF thermal sprayer for the improvement of the surface properties of the substrate. The optimal coating process for the highest surface hardness was obtained using the Taguchi experimental program. The coating was laser heat-treated (LH) by CO2(g) laser for further improvement of the properties. During the thermal spraying, a small portion of metal carbides of powder decomposed to W2C, metals and free carbon. The free carbon reacted with excessively sprayed oxygen, and formed carbon oxide gases, forming porous coating. By laser-heating, porosity decreased and the porous strips at the interface of coating and substrate (coat/sub) compacted. At the interface, the precipitated graphite concentration decreased and the metal elements diffused from both the coating and substrate increased, enhancing the functions as buffer zone and increasing adhesion of coating. The surface hardness of substrate increased by coating and further increased by laser-heating from 410±30 Hv to 983±101 Hv and 1425±94 Hv respectively. Porosity of coating decreased by laser-heating from 2.6±0.4% to 0.35±0.06%, and coating thickness shrank from 280㎛ to 200㎛. Friction coefficients of substrate decreased from 0.52±0.02 to 0.36±0.04 by coating, because the free carbon formed by decomposition of WC to W2C functioned as a solid lubricant. By increasing sliding surface temperature from 25°C to 450°C, the friction coefficients of substrate and coating were decreased from 0.52±0.02 to 0.31±0.02 and from 0.36±0.04 to 0.23±0.04 respectively, because of easy formation of free carbon and metal oxides which functioned as solid lubricants. Wear depth of surface was decreased by coating and by LH coating from 55µm to 32 µm and to 12 µm respectively. HVOF coating of WC-metal powder on In718 surface and laser heat-treatment of the coating are highly recommended for the improvement of the properties of magnetic bearing shaft.
Influence of Carbon Content on the Solid-State Shrinkage and Expansion of Carbon Steel
Authors: Wang Bo , Li Qing Chun , Yue Xu Dong , Chen Shu Ying , Chang Guo Wei
Published: August 2012

The self-made device to test the shrinkage ratio and temperature of cast ingot is used to measure the shrinkage mass of Fe-0.1%C, Fe-0.15%C, Fe-0.33%C cast ingot with the dimension of 200×80×100mm. The results show that the total shrinkage mass of cast ingot is increased with the increase of carbon content. In the carbon content range of the experiment, the rate of shrinkage and expansion of Fe-0.15%C steel during, before and after eutectoid reaction is all the quickest. The solid-state shrinkage rate of Fe-0.15%C steel before eutectoid reaction is 288 μm•s-1. The shrinkage mass and rate of cast ingot after eutectoid reaction are 0.051 mm and 127 μm•s-1, respectively. The expansion mass and rate of cast ingot during eutectoid reaction are 0.016 mm and 53.3 μm•s-1, respectively.
The Oxidation of Co-5Si Alloys in 1 atm of Pure O2 at 700 and 800°C
Authors: Zhang Hong Hua , Xiang Jun Huai , Sun Hai Ying , Li Yi
Published: August 2012

The kinetics and products of oxidation of binary Co-5Si alloys in 1 atm of pure O2 at 700 and 800 oC were investigated. Co-5Si alloys followed a parabolic behavior to a good approximation (n=2). The parabolic rate constants as functions of temperature were 2.789×10-11, 2.240×10-10 g2cm-4s-1 at 700 and 800 oC, respectively. The scales formed on Co-5Si alloys were double-layered, with formation of an outer layer of columnar CoO and an inner region containing a mixture of SiO2 and CoO, coupled to the internal oxidation region of Si.
Hot Compressive Behavior of Ti-3.0Al-3.7Cr-2.0Fe Titanium Alloy at Different Strain Rates
Authors: Wang Guo , Hui Song Xiao , Ye Wen Jun
Published: August 2012

The characteristics of hot compression deformation of Ti-3.0Al-3.7Cr-2.0Fe titanium alloy have been studied by Gleeble−1500D thermal simulated test machine in the strain rates range 0.01～10s−1 and temperature range 800～950°C. The true stress-true strain curves show that the peak flow stress decrease with increase temperature and decrease strain rate. At the temperature range in the article, there is a distinct peak in the flow stress in the early stage deformation followed by a stable state at high strains. The variation of flow stress with temperature and strain rate follows the standard kinetic rate equation and the apparent activation energy is estimated to be about 214.22KJ•mol-1. The constitutive relationship of Ti-3.0Al-3.7Cr-2.0Fe alloy is obtained on the base of Arrhenius equation at the experimental conditions.
Preparation and Characterization of Blackening Films in Steel Surface
Authors: Chen Ze Min , Lu Pin , Gao Jing Yin , Cai Jian Gong
Published: August 2012

With antimony trichloride, tartaric acid, sodium molybdate, hydrochloric acid, sodium silicate as the main raw material, a black chemical conversion coating treatment process was developed in the steel surface by the impregnation method at room temperature, and analyzed the films by SEM, XPS, XRD method. The results showed that: the film was a single black mass of antimony-based, and contains a small amount of Al2O3•2SiO2•3H2O crystal composite coating. It showed the crystalline structure in the scanning electron microscope, then preliminary analysis the mechanism on this based.
3-D Coupled Thermo-Mechanical FE Modelling and Simulation of Combined Ring Rolling
Authors: Zhang Zhi Qiang , Qian Dong Sheng , Hua Lin
Published: August 2012

Ring parts of duplicate gear, double-side flange, high pressure value body, are widely used in engineering machinery, have the common geometrical characteristic of thick-wall, small-hole and deep-groove on the surface. High energy consumption, low material utilization, low productivity and poor quality exist in the current forging technology of this type of rings. In this paper, a new forming method for this type of rings named combined ring rolling (CRR) is proposed. The forming principle of CRR is introduced at first, then, a 3-D coupled thermo-mechanical FE model for the CRR process of a double-side flange ring is developed. By simulation and analysis, the feasibility of CRR technology is testified, and the evolution and distribution rules of stain, temperature, force and power in the rolling process are revealed. The results provide the guideline for the research and development of CRR technology.
Modeling and Calculation of Initial Ignition Gas Pressure Flow through the Rigid Porous Media in 100 mm Ignition Simulator
Authors: Xiao Zheng Gang , He Wei Dong , Ying San Jiu , Xu Fu Ming
Published: August 2012

To acquire better understanding of the early ignition phenomena in 100mm ignition simulator loaded with packed propellant bed, a theoretical model of ignition gas flow through rigid porous media is developed. Three pressure gauges are installed in the lateral side of ignition simulator for chamber pressure measurements after ignition. The pseupropellant loaded in the chamber is similar to the standard 13/19 single-base cylindrical propellant in size. It is composed of rigid ceramic composite with low thermo conductivity. It is assumed that the pseupropellant bed is rigid in contrast to the previous elastic porous media assumption. The calculated pressure values can be verified by the experimental data well at the low loading density of pseupropellant bed of 0.18 g/cm3. However, there is still error between the experimental and calculated results in the early pressure peak position close to the ignition primer when the loading density of pseupropellant bed increases to 0.73 and 1.06g/cm3, due to the change of local permeability of pseupropellant bed at high loading density, which is assumed a constant in the model for the modeling easily. The calculations can enable better understanding of physical processes of ignition gas flow in the ignition simulator loaded with the pseupropellant bed.
Mass Transfer Model for Coated Urea Particle in Controlling-Release Process
Authors: Hao Shi Xiong , Liu Xing Yong , Yu Zu Xiao
Published: August 2012

Based on mass conservation and Fick’s diffusion law, a model for describing the nutrient release from coated urea particles was proposed. This model was verified by the release data of three novel paraffin- rosin coated urea in distilled water. The results indicate that the model is effective in describing and predicting the delivery behaviors for a diffusion-controlled coated- urea and their correlation coefficients R2 are 0.9976, 0.9973 and 0.9984, respectively. The model shows that the nutrient release rate for coated urea is direct proportion to effective diffusion coefficient Deff, inverse proportion to diameter’s square of urea granule and inverse proportion to the coating thickness.
Molecular Dynamic Simulation for Co Cluster Deposition on Si Substrate
Authors: Hwang Shun Fa , Li Yi Hung , Hong Zheng Han
Published: August 2012

Molecular dynamic simulation for Co cluster deposition on Si substrate was investigated in this work. The surface roughness and the interface mixing will be evaluated for the deposited film quality under different incident energies and substrate temperatures. The effect of thermal annealing on the ability of gap filling will be discussed by a slip vector. The results indicate that the incident energy has dominant effect on the surface roughness, and there is a minimum surface roughness value around the incident energy of 8 eV. However, the substrate temperature has little effect on the surface roughness. For interface mixing, the simulation indicates the easy diffusion of Co atoms into Si substrate. However, increasing either the incident energy or the substrate temperature could not change much the mixing conditions. As for the ability of gap filling, it is clear that the thermal annealing does improve this ability and obtains better surface roughness and interface mixing.
Heat Transfer of Bottom Tubes in Delayed Coking Furnace: Simulation and Measurement
Authors: Yang Jun Wei , Wang Lan Juan , Xiao Jia Zhi , Yang Chao He
Published: August 2012

Adding tubes on the bottom of delayed coking furnace is an useful measure for enhancing the throughput, but the distance between tubes and burners is too small to conform design standard. The security of these bottom tubes is uncertain. The processes of turbulence, combustion and heat transfer in the furnace were simulated by numerical method. Detailed information of velocity field, temperature field and heat flux was obtained. The heat transfer of tubes in entrainment zone of jet flame was investigated. The possibility of tube oxidation and hot spot was also discussed. Results show that the bottom tubes are security, which located in the low temperature field and the range of heat flux is 22~45 kW/m2. The results are in good agreement with industrial testing data.
Data Collection for Power Generator Condition Monitoring by Chemical ‎Analysis of Cooling Gas
Authors: Sarabi Soheila Dalirian , Ahmadi S. Ahmad , Alizadeh Reza
Published: August 2012

Power generator used as one of the main parts of a power plant, plays a big role in power ‎generation. Its high performance in continuous power generation is very important. Parameters of ‎temperature, insulating materials quality and performance of its cooling system affect on its ‎efficiency and lifetime. Cooling gas temperature monitoring can help us control it in the suitable ‎range, and as the gas is circulated inside the generator area, it can help scientists to find probable ‎defects of the system [1]. Organic insulating materials used in big power generators, degrade and ‎overheat after working long time, or because of electrical defects, and cause thermal decomposed ‎sub micron products entrained in the gas stream coolant of power generator [2]. By sampling and ‎chemical analysis of cooling gas detection of sub micron decomposition products is possible. ‎Therefore it is possible to prevent some unexpected troubles in different parts of generators like ‎stator core, rotor or stator winding [4]. This paper contains design and development of a system for ‎simulating of insulating material and coatings thermal decomposition with the same atmosphere as ‎generators, named Pyrolyzer, which has a hot plate to pyrolysis electrical insulating materials, and ‎on other hand decrease the temperature of the inside atmosphere to room temperature. And then ‎explains pyrolysis of insulators, sampling of cooling gas impurities, analysis of impurities by GC-‎MS, and identification of the overheat products, in order to use them as patterns and witnesses of ‎condition monitoring analysis of power generators.‎
Numerical Investigation of Hydrodynamic Behaviors in Gas-Solid Magnetic Fluidized Beds
Authors: Li Hui , Yang Hui
Published: August 2012

A mathematical model describing the transient hydrodynamic behaviours is introduced to predict the effect of magnetic field intensity and process parameters in magnetically stable fluidized beds (MSFBs). Computational fluid dynamics (CFD) code Fluent 6.2 has been used to investigate the hydrodynamics of a gas-solid MSFB operated with fine particles. The model is incorporated into simulations based on an Eulerian approach. In the simulations, the closure models describing the hydrodynamics of the solids phase are directly affected by the behavior of magnetic field intensity. The simulations are compared with experiments at different gas Reynolds numbers (ReG = uGdp/vG) and magnetic field intensity (Er = 3μ0MpH/2gdpρp). The agreement obtained between the simulation results and experimental data for local solid holdup is good at lower ReG and Er values.
Fire Performances, Hot Properties and Decomposition Kinetics of Sb2O3/DBDPE/RTV
Authors: Wang Juan Juan , Li Wen Xing , Feng La Jun
Published: August 2012

Fire and hot properties of title composite were taken by the method of vertical burning, OI, and TG. Fire performance experiments demonstrated that the scale of flame retardant property of Sb2O3/ DBDPE/RTV was FV-0, OI was 46. Hot decomposition temperature is about 400 oC to 520 oC with the amount of 20wt% as additives. The kinetic parameters of the decomposition reaction of the title composite have been studied by means of DSC. The data are fitted to the integral, differential and exothermic rate equations by linear least-squares, iterative, combined dichotomous and least-squares methods, respectively. The study leads the reader to the conclusion that the empirical kinetic model functions in differential form, the values of and of this reaction were , -1857.20 kJ/mol and 244.9 s-1 respectively. Sb2O3/ DBDPE are a kind of flame retardant which own its flame retardant function to higher activation energy but the release of halogen. It is a usable retardant during the lifetime.
Thermal Properties of Carbon/Epoxy Resin Composites Based on the Template of Artificial Sponge
Authors: Wang Tian Chi , Chang Li Jing , Wong Ching Ping
Published: August 2012

Artificial sponge was used as the template to produce carbon/epoxy resin composites with interpenetrating network structure. Carbon with a network structure was first obtained by the pyrolysis of sponge. The composites were then obtained by injecting epoxy resin into the carbon. Their microstructures, thermal diffusivity, and thermal expansions were analyzed. The results show that the structure of sponge controlled the interpenetrating network structures of the carbon/epoxy resin composites. The composites exhibit a lower coefficient of thermal expansion and a high thermal diffusivity than the epoxy resin.
The Study of Fe-Based Broad Amorphous Ribbon’s Variable-Temperature Kinetics
Authors: Gui Qiang , Wang Li Jun
Published: August 2012

Variable temperature kinetics under different heating rates for the Fe-based amorphous ribbons are studied by differential scanning calorimeter (DSC) technology. The results show that imported and domestic amorphous ribbons have the same overheating degree under the same heating rate, and the initial crystallization temperature is proportional to the cube root of the heating rate. The calculation indicate that the crystallization activation energy of imported and domestic amorphous ribbons are about 297~300 kJ/mol and 335~340 kJ/mol, respectively.
Effect of Particle Size on the Zener Limit: A Monte Carlo Simulation Approach
Authors: Phaneesh Kalale Raghavendra Rao , Bhat Anirudh , Mukherjee Gautam , Kashyap Kishore T.
Published: August 2012

2D Potts model Monte Carlo simulation was carried out on a square lattice to investigate the effects of varying the size of second phase particles on the Zener limit of grain growth, in two-phase polycrystals. Simulations were carried out on a 1000^2 size matrix with Q-state of 64, dispersed with second phase particles of various sizes and surface fractions, and run to stagnation. Different grain growth parameters such as mean grain size, largest grain size, fraction of second phase particles lying on grain boundaries, etc., were computed for the pinned microstructures. The pinned average grain size or the Zener limit increased with increase in particle size, as per the classic Smith-Zener equation. The Zener limit scaled inversely with the square root of the particle fraction for all particle sizes, while it scaled exponentially with the fraction of second phase particles lying on the grain boundaries (ϕ), for all particle sizes tested.
Thermal Stabilization of γ-Al2O3 with Modification of Polyethylene Glycol by Reverse Precipitation Method
Authors: Wu Yu Sheng , Ma Jiao , Hu Fang
Published: August 2012

A series of γ-Al2O3 modified with different content of polyethylene glycol (PEG) was prepared by a reverse precipitation method. The phase transformation, thermal stabilization and the morphology of PEG-modified γ-Al2O3 was studied by XRD, BET and TEM, respectively. The results showed that the γ-Al2O3 with 1mol% PEG-modified has the excellent thermal stabilization after calcined at 1100°C for 3h. With the content of PEG increasing, the surface area of γ-Al2O3 was reduced gradually. Simultaneity, the γ-Al2O3 phase was transferred to θ-Al2O3 with the surface area 92 m2g-1 and a pore volume of 0.77 cm3g-1. The high surface area maintained at such high treatment temperature shows the 1mol% PEG-modified γ-Al2O3 prepared by reverse precipitation method can be applied in the automotive three-way catalyst support.
Kinetics of Epoxidation of Vegetable Oils Catalyzed by Formic Acid, Peroxophosphatotungstate and Methyltrioxorhenium
Authors: Zhang Wei Jie , Jiang Ping Ping , Wu Feng Juan , Chen Min
Published: August 2012

The kinetics of epoxidation of vegetable oils by traditional route (formic acid) or novel routes (peroxophosphatotungstate, methyltrioxorhenium) with hydrogen peroxide (H2O2, 30 wt. %) were investigated. The mathematical models describing the kinetics of epoxidation were developed. Using a linear fit method, kinetic parameters were estimated by fitting experimental data. The activation energy of the epoxidation reaction decreased in the following order: peroxophosphatotungstate > formic acid > methyltrioxorhenium. Other oils were also investigated under the same conditions. Results showed that the activation energy of epoxidation was in the order; rapeseed oil < fatty acid methyl ester < soybean oil < sunflower oil. Thermodynamic parameters of the epoxidation of vegetable oils were also obtained.
The Microwave Synthesis and Photocatalytic Activity of Silver Vanadate
Authors: Liao Xue Hong , Liu Yi , Xu Zhi Hua , Chen Xiao Dong , Wang Ru
Published: August 2012

Using one simple microwave synthesis method, take silver nitrate and vanadium(V) oxide as raw meterial to synthesize Silver Vanadate. The photocatalytic degradation of methyl orange under visible light irradation showed that the photocatalytic activities of microwave synthetic samples were better than those of samples produced by conventional hydrothermal technique. This experiment is to discuss the impact of these factors upon the catalyst performance through the control of the calcine temperature, the quantity of hydrogen peroxide, pH, the concentration of methyl orange and the quantity of catalyst. When the catalyst was calcined at 500 °C ,0.1 g, and 0.5 mL hydrogen peroxide joinded as well as pH was 2.0, the degradation ratio of Ag3VO4 for methyl orange of 100 mL 5 mg/L reached 91.49％ in 40 min.
Effect of pH on the Phosphorous Components in Tetra-Hydroxymethyl Phosphonium Chloride Solution
Authors: Shao Shuang Xi , Jiang Lan , Li Ya , Shi Kai Qi
Published: August 2012

At present, tetra-hydroxymethyl phosphonium chloride (THPC) is widely used in flame retardant finishing, industrial water treatment and leather manufacture industry etc., and its decomposition which was caused by pH changing will influence on the actual application. So acid-alkali decomposition of THPC was studied by 31P Nuclear Magnetism Resomance (31P NMR), spectrophotometry and titration respectively. The results show that THPC solution is stable when pH9.0, all of the phosphorus compounds converts to TrHPO. Consequently, THPC content decreases when pH of the THPC solution rising, which could give a favorable guide in THPC application.
FT-IR Studies of Acid Properties of Physically Mixed Mo/HZSM-5 Catalysts for Methane Dehydroaromatization
Authors: Jiang Hong Tao , Zhang Zhan Guo , Ji Jian Bing
Published: August 2012

The MoO3/H-ZSM5 catalysts for CH4 dehydroaromatization are prepared by physically mixing MoO3 and HZSM-5 and calcining the mixtures under different atmospheres at different temperatures. Transmission infrared spectra have been used to characterize the acidic properties of the MoO3/HZSM-5 catalysts. On the base of observations obtained the effects of the calicination temperature and environment were discussed on the migration of Mo and its dispersion over HZSM-5.
Thermal Treatment of New Inorganic Thermal Insulation Board Based on Expanded Perlite
Authors: Skubic Blaž , Lakner Mitja , Plazl Igor
Published: August 2012

A new lightweight thermal insulation board, containing expanded perlite and inorganic silicate binder with corresponding industrial production procedure was developed. The industrial technology was developed in cooperation between company Trimo d.d. and Faculty of chemistry and chemical technology Ljubljana and among others includes mixing of raw materials, molding, microwave drying and high temperature treatment of the dried board. A new product has low density (130 – 160 kg/m3), good mechanical properties and durability and can be used in various fields where inorganic thermal insulation is required. The current work presents the experimental study of the final process during plate production – high temperature treatment with sintering. During thermal treatment of the board, certain shrinkage is required to obtain sufficient mechanical properties and durability. Controlling the process of high temperature thermal treatment is the key to achieve the right balance between low final density of the board and its good mechanical properties.
Qn Distribution in Silicates: Alkali Silicate Glasses and Melts
Authors: Osipov Armenak A. , Osipova Leyla M.
Published: August 2012

Three-parameter statistical method of the calculation of Qn distribution in silicate melts and glasses has been developed. The method allows determining the concentrations of silicate structural units in wide compositions range at different temperatures when only the limited experimental data are available. The method is based on a destruction of the preassigned network as a model of the interaction of the modifier oxide with a silicon-oxygen framework. Qn distributions in binary alkali silicate glasses and melts were determined by this method. It was found that Qn distribution does not depend on a topology or dimension of the initial network. Moreover, a linear correlations were found to be exist between ln(1/wi) values (w1 and w2 are the first and second adjustment parameters) and 1/rM (rM is cation radius, M = Li, Na, K, Rb, Cs). These correlations allow using the concept of a “fictitious” cation radius in order to calculate of the Qn units at different temperatures.
Preparation of Carbon Micro-Spheres from Liquefaction Products of Lignite with NaOH-Methanol
Authors: Lei Zhi Ping , Gao Li Juan , Shui Heng Fu , Wang Zhi Cai , Ren Shi Biao
Published: August 2012

Carbon micro-spheres (CMSs) with diameters of several micrometers were synthesized by surfactant-assisted self-assembly of direct coal liquefaction products, which come from the lignite liquefaction with NaOH and methanol. The synthesized CMSs were characterized by X-ray diffraction, scanning electron microscope and TG analysis. The results show that cetyltrimethylammonium bromide (CTAB) and carbonization temperature play an important role in the formation of CMSs. The CMSs have a spherical morphology, smooth surface, probable size of about 5-10μm and a relatively high thermal resistance in N2 atmosphere. The formation mechanism of these CMSs was discussed based on the feature of the reaction system.
Synthesis of (R)-(-)-Mandelic Acid Ethyl Ester by Asymmetric Reduction of Ethyl Benzoylformate with Yeast Cells
Authors: Ou Zhi Min , Nan Ying Kang
Published: August 2012

An efficient yeast cell biotransformation process was set up for asymmetric synthesis of (R)-(-)-mandelic acid ethyl ester, a key drug intermediate. Saccharomyces cerevisiae 21 was selected as optimum strain for biotransformation. The optimum reduction conditions are as follows: substrate concentration 20 g/L, cell concentration 140 g/L, reaction time 36 h, temperature 30 0C. Conversion and enantiometric excess of (R)-(-)-mandelic acid ethyl ester reached 99.8 % and 100%.
Measurement and Correlation of Solubilities and Surface Tension of Caffeine in Water
Authors: Zhu Zhao You , Zhang Da Wei , Wang Ying Long
Published: August 2012

The solubility of caffeine in water between 323.15 and 353.15 K was measured using the balance method. The solubility trend was modeled by use of the modified Apelblat equation and Yaws equation. The calculated solubility values according to the two empirical equations compare favorably with the experimental data. Besides, the relationship between supersaturated ratio and induction time was studied with the method of laser, basing on which, the surface tension of caffeine at 283.15 K, 293.15 K and 298.15 K in water was calculated.
Preparation of Pt-Sn-K/Al2O3 Catalysts and its Catalytic Performance in Propane Dehydrogenation
Authors: Li Jun , Wang Ning Ning , Ma Zhan Hua
Published: August 2012

Al2O3 supported platinum catalysts prepared by using different impregnation methods have been tested for the dehydrogenation of propane to propylene. The effect of promoter type and amounts of promoters has been investigated in a detail. The results indicated that the best catalytic performance was achieved on the catalyst prepared under the following conditions: sequential impregnation method, Sn and K as promoter, Pt loading 0.5%, Sn loading 1.0%, K loading 2.1%.
A Study on Catalytic Hydrolysis of Corncob by Formic Acid
Authors: Xue Jing Wen , Wang Zhe
Published: August 2012

Corncob powder was hydrolyzed with formic acid under the catalyzation of hydrochloric acid. Sugar contents in hydrolysis liquor at different reaction time and temperature were determined. The chemical compositions in hydrolysis residue were also analyzed. Results showed that the formic acid could hydrolyze the polysaccharides in corncob and the degradation products were dissolved in hydrolysis liquor. The addition of catalytic hydrochloric acid accelerated the hydrolysis of polyose. The proper hydrolysis condition was 80°C for 3h. Lignin might undergo hydrolysis at higher temperature.
The Microscopic Mechanism of Compton Scattering of Some Saline Solutions
Authors: Luo Guang , Hu Xian Quan , Xiao Guang Yu , Kong Chun Yang
Published: August 2012

Based on preliminary research results about Compton scattering of saline solution, a linear relationship between the scattered photon counts and the concentrations had been deduced for a certain solution and it had been found that the slope of the lines was decreasing with the atomic number of the cation increasing for LiC1, NaCl and KC1(the same result for MgC1BB2BB and BaC1BB2BB) solution. Now, in order to explain such rule of the slope, the microscopic mechanism of scatterers has been studied. Through the electronic structure of hydrated ions is analyzed in detail: the distance between hydration ion and O atom after optimized, the total energy of hydration ion, the equivalent charge distribution of hydration ion and the electronic density distribution of hydration ion. At last, it is concluded that the reason of the slope decreasing when the atomic number of the alkali cation for KC1, NaCl, LiCl solutions (or MgC1BB2BB and BaClBB2BB solutions) is the bounding strength of the system on its electrons become increasing, the probability of Compton scattering is decreasing, and it will constrain the increasing velocity of the scattered photon counts.
The Application of Cellular Automata in the Dumping Site Analysis
Authors: Wang Guang Jin , Liu Tian Jun , Dong Wen Bin , Kong Xiang Yun
Published: August 2012

Based on Cellular Automata method，The article developed the HHC-CA model which generated the granular samples of different fabric to characterize the heterogeneous and random distribution of samples group．Then by means of FLAC3D，conducting triaxial numerical simulation tests of granular samples and acquiring the average cohesion C and average internal frictional angle of different relative height．In addition，on the basis of on-site survey of granular size distribution，the slope model of current situation，had considered the features of particle size grading，was established according to Xiyuanlin 413 step dumping site．The results of slope stability analysis indicated that the upper displacement vector，whose displacement direction maintained the same direction of the current situation slope of Xiyuanlin 413 step dumping site，performanced for subsidence．The middle displacement vector showed shear and the displacement vector of bottom had slightly the trend of anti-lift．The slope failure model of current situation expressed in crack at the top platform and shearing out with a arc in the middle．This status of current situation slope was temporary steady stage．
Levitated Drop Microreactors for Biochemical Kinetics
Authors: Scheeline Alexander , Choi Woo Hyuck , Chainani Edward T. , Ngo Khan T.
Published: August 2012

Ultrasonically-levitated drops have been widely studied for materials processing and for sample preparation for chemical analysis. We report on the development of such drops for study of kinetics of enzyme-catalyzed reactions and other chemical processes. We review how to simply and reliably levitate drops, discuss why such drops are desirable for studying biochemical reactions, especially those generating or consuming free radicals, and report progress towards routine kinetics measurements in microliter drops.
Biomimetic Pattern Recognition Method for Breast Cancer Using Gene Expression Data
Authors: Yang Xiao Li , Yang Si Ya , He Qiong , Zhao Hong Yan
Published: August 2012

The purpose of this study was to develop a novel prediction method for breast cancer based on gene expression data through using a susceptible marker-selectable biomimetic pattern recognition (BPR) method, with which a parameter increasing method (PIM) was proposed to incorporate. The method was used to predict early detection, transition from normal cell to cancerous cell and prognosis signature of patients with adjuvant systemic therapy. Several genes were selected as susceptible genes associated with breast cancer. It can be shown by the results that the “cognition” BPR method could correctly predict detection, cancerous cell transition and good or poor prognosis signature with approximate 85%, 98% and 88% accuracy separately. In order to study the performance of BPR, Fisher discriminant analysis (FDA) and support vector machine (SVM) methods also were applied to analyze the gene expression data. From the results, it can be found that the BPR method is superior to FDA and SVM with respect to classification ability. Furthermore, the prediction performance can be improved through using biomarker instead of whole gene expression data for any method.
Preparation of N, O-carboxymethyl chitosan-Human-Like Collagen Microspheres for Drug Delivery
Authors: Ma Pei , Su Ran , Fan Dai Di
Published: August 2012

In this investigation, the N, O-carboxymethyl chitosan (NOCC) was synthesized. A novel pH-sensitive hydrogel system composed of a water-soluble chitosan derivative (N,O-carboxymethyl chitosan, NOCC)and Human-like collagen (HLC) blended with phosphate was developed for controlling drug delivery and NOCC–HLC microspheres were prepared by the technology of electrostatic droplet generation technique. The release profiles of a model protein drug (bovine serum albumin, BSA) from test hydrogels were studied in simulated gastric and intestinal media.
Comparative Evaluation of the Chemical Composition of Essential Oil from Different Parts of Ficus microcarpa
Authors: Lin Qiang , Liu Yan Feng , Chen Yu Kai , Wang Zhao , Liang Zhen Yi , Feng Yu Hong , Xu Jing
Published: August 2012

This study was designed to comparative evaluate the chemical composition of the essential oil from leaf, aerial root, twig, root and bark parts of Ficus microcarpa L.f. (Moraceace). Gas chromatography (GC) and gas chromatography/mass spectrometry (GC–MS) analyses of the oils revealed the presence of 6, 6, 5, 5 and 5 compounds in the essential oils obtained by hydrodistillation from different parts, respectively. The total yield of the volatile fractions was subsequently 1.89%, 0.87%, 1.27%, 0.97% and 0.71%. Higher amounts of aliphatic acids were found to compose a major chemotype in diverse parts of the plant. n-Hexadecanoic acid, elaidic acid and linoleic acid were the main and common component of all the essential oils totally attaining in average 74%, 87%, 56%, 46% and 88%, independently. In addition, some pharmaceutical components such as elaidic acid, linoleic acid and squalene were discovered. The study offers theoretic basis for utilization of the traditional folk herb F. microcarpa.
Auto-Catalytic Ethanol Pulping of Corncob Acid Hydrolyzed Residua
Authors: Li Jie , Xiong Lian , Zhang Hai Rong , Ding Fei , Chen Xin De
Published: August 2012

The effects of ethanol concentration, reaction time, solid-liquid ratio and temperature on auto-catalytic ethanol pulping reaction of corncob acid hydrolyzed residua were investigated. The relationships of those four factors and pulping selectivity(Y/K ratio) were also discussed. The optimal pulping conditions were determined, which were ethanol concentration 55%, reaction time 2.0h, solid-liquid ratio 1:10, temperature 175°C. The temperature has the most influential effect. Structures of corncob acid hydrolyzed residua and dry pulp were observed by electronic microscope. The process of pulping reaction and the delignification were also verified.
Separation Test of Refractory Lead-Zinc Ore from Myanmar
Authors: Hu Ting , Liu Quan Jun , Deng Rong Dong , Ye Feng Hong
Published: August 2012

The paper recovered the lead and zinc from a refractory oxide lead-zinc ore. The grade of lead is 3.97%, with the oxidation rate of 50%.The grade of zinc is 3.37%, with the oxidation rate of 10%.The test made the lead-zinc sulphide flotation first, depressing the zinc mineral and floating the lead mineral, then selected the oxide of lead by sulfidation. The experiment got the best pharmacy system by comparing the species and amount of agent. As a result, the lead sulphide concentrate with a grade of 45.32% and the recovery of 44.86%, the zinc concentrate with a grade of 50.19% and the recovery of 81.23%, the lead oxide concentrate with a grade of 50.37% and the recovery of 45.64% were obtained. Three products had received good indicators, and the issue of lead and zinc interacted with each other had been resolved.