bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Crack Length Measurement and Crack Tip Plastic Zone Determination by Infrared Thermography
Authors: Zhao Yan Guang , Liu Jian Zhong , Hu Ben Run , Chen Bo , Guo Xiang
Published: June 2014

This paper reports a new way to conduct fracture mechanics experiments of welded thin-walled structure for aircraft fuselage applications made of the Al 6156 ally using lock-in infrared thermography. The heat wave, generated by both the themo-mechanical coupling and intrinsic energy dissipation was detected by an infrared camera. The crack growth rate measured by the lock-in infrared thermography is found to be consistent with that measured by conventional method. It is observed that the crack can either grow underneath the stiffener or grow into the stiffener web with the crack length measured at the same time. In addition, the crack tip plastic zone was observed before the specimen was about to be destroyed.
The New Model of Laminar Cooling System and its Fieldbus System
Authors: Wang Hai Fang
Published: June 2014

Hot strip cooling temperature and its cooling rate is get by strip cooling system and coiling temperature of hot rolled strip is an important parameter on its performance index. A clew regarded as the laminar cooling control system is controlled by general linear analytical model. Under detailed analysis of its control system structure, basic theory, analytical method, system design and control method, the structure of the temperature control system is characterized by feed-forward control as the main combined with feed-backward control as the assistant, the configuration software for laminar cooling process is constructed, the mathematics model is present, the characteristic of emerging fieldbus control system is analyzed, and the configuration of fieldbus is brought forward and sketch of distributed structure of laminar cooling control system in a hot rolling mill based on fieldbus and intelligent sensor is presented.
Study on Energy Saving Model of Air Condition for Subway Station
Authors: Zhang Lin Xin , Li Gui Qin , Mitrouchev Peter , Guo Lei
Published: June 2014

In order to analyze air conditioner energy conservation of subway station quantitatively, three-dimensional numerical simulations study is conducted by using CFD theory for air distribution of subway platform, and the flow field and temperature field of the platform under different environment conditions are obtained. The orthogonal experiment method is applied to the numerical simulation analysis for human comfort under different parameters. Based on those results, the functional relationship between human comfort and the boundary conditions of the platform is produced by multiple linear regression fitting method, the order of major boundary conditions which affect human comfort is obtained. The experimental verification is also carried out, the simulation results are well coincided with experimental results. The above study provides a theoretical basis for the final energy-saving strategies.
Experimental Study on Film Cooling Efficiency of Flat Plate through Infrared Thermography Technique
Authors: Chen Wei , Shi Hong Hui , Dong Ruo Ling , Liu Lan Fei
Published: June 2014

Experimental investigations were performaed on the flat plate cooling effectiveness through infrared thermography technique. Surface temperature distribution on the flat plate was measured by means of infrared thermography. The experimental facility and infrared thermography method are described in detail. Tests were conducted under different blowing rations which range from 0.3 to 2.0. The result, presented in terms of cooling efficiency distribution along the plate surface shows the influence of blowing ration on heat transfer. The maximum cooling efficiency achieved in the immediate region with a blowing ration of 0.3, then decreases significantly along the streamwise direction. Cooling efficiency increase slightly at the high blowing ration in far downstream area because of the jet adhere to the plat again. Along the spanwise direction, the jet concentrated in the center of the hole at low blowing ration, while spread evenly at high blowing ration. The jet can take different forms, depengding on the blowing ration, the jet can remain attached, detach and reattach or lift-off comletely. Therefore, cooling efficiency does not change with blowing ration monotonously.
Modelisation of Calorific Capacity by the Debye and Brillouin Functions for the Formalization of the Magnetothermal Problem
Authors: Merouane Boudjemaa , Sebbani Mohamed
Published: June 2014

In the induction heating, in the calculation of the electric machines losses, in the mechanical engineering, in the calculation of the thermal field distribution, the equations of Maxwell and heat equation are required. Those utilize the magnetic permeability and the calorific capacity at constant volume which strongly depends on the temperature and the temperature of Debye, which is a constant for each metal.The Physics of the Solid State,through the study of the acoustic and thermal properties of metals, establishes a formula giving the calorific capacity at constant volume by an integral which one can calculate only numerically.That is due to the form even of the function of distribution of Debye. The purpose of this work is to propose an analytical formulation of the calorific capacity at constant volume by analogy with the Brillouin's function largely used in ferromagnetism.This formulation has the advantage to put at the disposal of the Engineer specific concepts to the Physicist. Another advantage is the facility of ‘’to keep’’ this new formulation by functions which come under the domain of Numerical Analysis, such spline function or other.This same formulation will also allow finding an analytical formulation of internal energy whereas it was given by an integral which one can calculate only numerically.
Thermal Insulative Performance of Bamboo Leaf Aerogel Opacified Using Activated Carbon Compared with Carbon Black
Authors: Kow Kien Woh , Yusoff Rozita , Abdul Aziz A. R. , Abdullah E. C.
Published: June 2014

Silica aerogel with extremely low thermal conductivity has great potential to be used as thermal insulating material. Opacification using carbon black is normally applied to reduce radiative heat loss in silica aerogel. This work attempted to replace carbon black with activated carbon as opacifer. Both the silica aerogel and activated carbon were synthesized via bamboo leaf. Effects of carbon loading and temperatures on the thermal conductivity of opacified aerogel were studied. The results show that an optimal carbon loading that minimized the thermal conductivity present at different temperatures. Such optimal loading increased as temperature applied to the opacified aerogel increased. Properties of aerogels opacified with activated carbon were also compared with aerogels opacified with carbon black.
The Influence of Induction Heating to Remelting Temperature Radial Distribution
Authors: Jia Yu Xian , Wang Cheng Zhi
Published: June 2014

The second remelt is an important influencing factor during semi-solid thixotropy forming technology, and the microstructure is immediately impacted by temperature distribution state. By the way of induction heating the temperature distribution state of 45# steel is researched in this paper. The results indicate: the temperature rises slowly by low power heating and the radial temperature distribution doesn’t reach uniform. But the temperature rises rapidly by high power heating and the radial temperature distribution is nearly homogeneous after a while.
Research on Design and Principles of New Regenerant for Restoring Performance of Aged Pitch
Authors: Song Xiao Yan , Miao Qian
Published: June 2014

The thesis applies the theory of pitch intermiscibility and adopts the orthogonal test to develop the new pitch regenerant through the regression analysis to the test results. Besides, according to the regeneration mechanism, the concentration of the regenerant and the intermiscibility of the regenerant and the pitch also should be taken into consideration.
Study on the Abutment Pressure and Advanced Support of Driving Roadway along Goaf of Isolated Mining Face
Authors: Li Li , Zhang An Bin , Zhang Chun Lei
Published: June 2014

WuTongZhuang No.182309 mining face is an isolated mining face. The abutment pressure is big and roadway deformation is severe due to driving roadway along goaf with short pillar remained. In view of these problems, taking WuTongZhuang No.182309 mining face as project background, the law of the abutment stress distribution was analyzed by use of numerical simulation software FLAC3D and field measurement study. The results showed that the influence scope of the lead abutment pressure was about 55m , the peak value was about 6m ahead of the mining face and the stress concentration factor is 3.3.Based on the above study results, a scheme of advanced support was proposed which effectively controlled the roadway deformation and ensured the safety production of the mining face.
Study on Variation Regular Pattern of Development Indexes in Beierdong Block after Layer Recombination
Authors: Song Li Yang , Mou Jian Ye , Zhang Ji Cheng , Wang Ji Wei
Published: June 2014

Nowadays, in China nearly all the produced oil-fields have already entered the period of high water cut, and the six oil-fields of Daqing and Shengli oil-field etc. have exceeded eighty percent water cut. Beierdong Block has produced for nearly fifty years, and now it has entered into the descending output stage and its water cut has reached more than ninety percent. With oil field infill gradually in Beierdong Block, each series of well network production target getting worse gradually, intersecting with old well network stratigraphic position, and polymer flooding well network use part of water driving old well, making the contradictory of layer well network concatenate and dynamic regulation intensely. Especially as the block of infill adjustment proceeded earliest, acquired better developed effect at the beginning of regulation, but with the deep development of the field, after the phase of extra high water cut, exposed gradually some problems such as the perforating interval is too long, the contradiction of interlamination is obvious, the high water cut of multilayer is serious, bringing huge difficulty to dynamic analysis regulation[1]. Basing on layer recombination and using the reservoir simulation method, the paper studied the distribution of remaining oil, forecast variation regular pattern of development indexes. By contrasting these indexes, the paper estimates the effect of layer recombination. It has important significance for the next period’s development.
Hot Deformation Behavior and Microstructural Evolution of Al-Zn-Mg-Cu Alloy with Different Starting Structures
Authors: Zhao Xiao Dong , Chen Hui Qin , Liu Jian Sheng
Published: June 2014

Hot Deformation behaviors and microstructural evolution of Al-Zn-Mg-Cu alloy with as-homogenized, as-forged and as-over-aged starting structures were studied at temperatures in the range of 300-420°C, strain rates in the range of 0.01-1s-1, and reductions in the range of 20%-80% by high-temperature compression tests. The flow stresses increase with increasing strain rate or decreasing temperature, which can be described by a hyperbolic-sine equation with the deformation activation energies of 246.35KJ/mol, 188.87KJ/mol and 178.25KJ/mol for the homogenized, the forged and the over-aged samples respectively. At the same deformation condition, the flow stress of the homogenized samples is greater than that of the forged and over-aged samples. For the homogenized samples, dendritic coarse grains elongated along the deformation direction, and interdendritic boundaries within coarse grains disappeared gradually due to diffusion at higher temperatures. When deformation is heavy, microstructures became into homogenous and geometric recrystallization occurs and new small grains appear within the severe elongated grains. For the forged samples, higher temperatures promote dynamic recrystallization. Recrystallized new small grains were developed along prior grain boundaries at large strains. For the over-aged samples, prior grains elongated along the deformation direction, and there is not much more dynamic recrystallized grains observed.
Research on Rock Mechanics Characteristics of Mud Sandstone NanTun Formation of HaiLaEr Oilfield
Authors: Liu Yi Kun , He Yang , Wang Feng Jiao , Wang Yong Ping , Tang Hui Min , Jiang Ying Nan
Published: June 2014

Hailar oilfield Nantun Formation is a set of lacustrine sedimentation, the sedimentation dominated by gravity flow,the rock contains a lot of argillaceous components. This paper analyzes the content of mud in mud sandstone in Nantun Formation by means of X-ray diffractometer, the rock mechanics parameters were measured.The results show that mud content increases with the decrease of the young's modulus, mud content increases with the increase of the Poisson's ratio; at the same time, with the increasing of the shale content, the compressive strength of rock reduce, and the tensile strength showed increasing trend; different clay contents of mud sand rock stress strain relationship is not the same, when the clay content ≤20%, rock stress strain is elastic constitutive relation, the shale content 20%-30%, the stress-strain relationship is approximate to the ideal elastic-plastic, shale content ≥30%, stress strain relation of rock strain hardening and softening of two parts including plastic deformation. Fault mud sandstone first with increasing clay content decreases, when the rock is elastic plasticity, fracture little overall change.
Effects of Fillers on the Dynamic Properties of a High Performance Elastomer at Varying Strain Amplitude
Authors: Ghezzo Fabrizia , Miao Xi Geng , Ji Chun Lin , Liu Ruo Peng
Published: June 2014

In recent years, polyurea has been successfully applied as a coating material for increasing the survivability of structures and components subjected to critical impact loading conditions. It was also shown that if a polyurea coating is reinforced with ceramic particles or short glass fibers, an enhanced benefit on the overall impact resistance due to the increased dissipation properties of the material can be observed. Notwithstanding the use of polyureas as coating materials for structures protection, other applications where control and damping of vibrations is of concern would benefit from the high dissipation characteristics of the reinforced elastomer. Nevertheless, there are well known drawbacks in the use of the reinforced elastomers which can be identified in their pronounced nonlinear behavior under cyclic loads and the softening of their mechanical properties. In order to investigate such a phenomenon, in this manuscript we present an experimental investigation conducted on the effects of different volume fractions of the same filler on the response of a polyurea elastomer at varying amplitudes of the applied strain. The characterization of the materials was conducted by using a dynamic mechanical analyzer (DMA). From our preliminary results we observed that in the case of polyurea reinforced with short glass fibers, the nonlinear response of the polymer at varying strain amplitudes becomes evident for fillers volume contents of 10%. Furthermore, the nonlinearity of the response of the material due to the Payne effect seems to be associated with the complex fibers-matrix interaction rather than the disruption of the agglomeration of the fillers under load.
Status Analysis of the Frozen Soil’s Dynamics Parameter Study
Authors: Cui Ling Zhi , Li Gao Min , He Yi Ting , Liao Qin , Luo Fei
Published: June 2014

In this paper, the author points out several key problems needed to be solved about the dynamics of frozen soil by reviewing related literatures about hysteretic curve of frozen soil ,dynamic constitutive relation and dynamical parameter. The problems are the insufficient understanding on morphological characteristics of hysteretic curve and how to transform qualitative understanding into quantitative understanding about morphological characteristics of hysteretic curve. The problem is the rationality of selecting the dynamic constitutive model, namely how to establish the engineering applicable model which conforms to the actual soil mechanics performance.The problem is the rationality of the calculation method about dynamic elastic modulus and damping ratio, namely how to define dynamic modulus of elasticity of frozen soil correctly and the limitation of using the classical method to calculate the damping.
Characterization and Application of Super Clean Coal
Authors: Cui Yong Mei , Xu Yong Quan , Hu Yong Qi , Yuan Zhong Kai , Li Li Ye , Zhang Zhao Xiang , Zhao Feng Yun
Published: June 2014

Industrial washing oil as solvent, super clean coal was extracted and prepared from raw coal using heat extraction technology. The structures of raw coal and super clean coal were characterized by thermogravimetry, Fu Liye infrared spectrum, Gieseler fluidity. The results showed that the heat extraction rate of super clean coal was decreased with the increasing of coalification degree. The ash of raw coal which were silicate and alumina can be concentrated by heat extraction technology into coal residue and the mixtures of various structure were mainly composed of aromatic hydrocarbons also can be extracted effectively. Compared with raw coal, the super clean coal had lower softening temperature,higher final fluid temperature and curing temperature,thus it had the plastic range wider. Thickness of plastic layer was determinate by 80%Si-ma lean coal matching 20% super clean coal which can be considered coking binder was obtained from Xiao-kang village 1/3 coking coal heat extraction. The Y value is 27.4. The coal coking was in complete fusion state after experiment.
Investigation of Surface Roughness after Turning of One Kind of the Bio-Material with Thermoplastic Matrix and Natural Fibers
Authors: Zajac Jozef , Hutyrová Zuzana , Orlovský Imrich
Published: June 2014

Study provides information about one type of bio-based composite – plastic with wood reinforcement in volume more than 50 % (advantage: renewable, inexpensive, can be used to isolate a sound and have got a low density) and about machining of this unique material. During the machining (turning process was use to produce a surfaces by removing material from a rotating workpiece) were changed two parameters – rotation speed and feed rate (depth of cut was constant). There were observed changes of parameter to surface roughness with change of conditions of machining process.
Microstructure and Tribological Properties of Cu-Fe Based Braking Materials
Authors: Wang Xiao Yang , Ru Hong Qiang
Published: June 2014

SiC particle-reinforced Cu-Fe based braking materials were fabricated by the P/M hot pressing method. The phase composition, microstructure and the worn surface of the composite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).The tribological properties were evaluated using a disk-on-disk type laboratory scale dynamometer. Results indicate that the friction coefficient is 0.42 in 6800rpm, 0.7MPa. With the increase of rotation speeds the coefficient of friction and stable rate were decreased.
Preparation and Characterization of Resin-Derived Carbon Foams Containing Hollow Microspheres
Authors: Wang Bin , Li He Jun , Li Yun Yu , Hu Man Hong , Xu Jing Xian , Cao Sheng
Published: June 2014

Resin-derived carbon foams with closed hollow spherical structure were prepared from mixtures of hollow phenolic microspheres and phenolic resin, followed by curing and carbonization. The resultant carbon foam had a bulk density of 0.45 g·cm-3. Effects of hollow microsphere on the on the compressive property and thermal conductivity of carbon foams were investigated. The results revealed that the hollow microspheres played an important role in improving compressive fracture toughness and lowering the thermal conductivity of carbon foams. The compressive fracture characteristics of carbon foam exhibited gradient brittle fracture, and the compressive strength was 10.93 MPa. The thermal conductivity of the carbon foam was 0.907 W·m-1·K-1 at room temperature, which was lowered by 49.67 % in comparison with phenolic-based vitreous carbon.
Investigation of Heat Treatment’s Influence on the Preparation of High Silicon Steel Composite Sheet
Authors: Yang Xing Wen , Liu Jing , Han Jing Tao , Ji Shuai
Published: June 2014

Fe-6.0wt%Si sheet with thickness of 0.4mm was prepared with the process of coating casting, rolling and some corresponding heat treatments. During the preparation process, the effect of heat-treatment on the material’s plasticity was investigated by observing the variations of microstructure, hardness and phase structure before and after the heat-treatment. After heat-treatment and warm rolling, the rolling plasticity of composite sheet was estimated. The results showed that the grains of the coating of composite plate were refined, the ordering degree of composite plate’s core layer phases was restrained or even decreased, and the whole plasticity was increased by different heat treatments. Moreover, the rolling plasticity of the composite sheet, which was dealt with heat treatment and brine quenching, was the most required.
Iron Loss Measurement on 6.5wt%Si Composite Plate Prepared by Clad Casting and Conventional Rolling Processes
Authors: Ji Shuai , Han Jing Tao , Liu Jing , Yang Xing Wen
Published: June 2014

The 6.5wt%Si composite plate, which contains three layers and the middle one is about 10wt% ferrosilicon alloy, is fabricated by clad casting and conventional thermomechanical processes. Experimental results reveal that the high silicon composite plate could get lager plastic deformation on the traditional rolling mill. Microstructure of different stages such as hot rolling, warm rolling and heat treatment are observed by optical microscope. Defects appeared in core layer of 6.5wt% high silicon composite plate could be eliminated in the diffusion annealing process. The values of iron loss are investigated at different frequencies which thickness of these homogenous thin sheets are near 0.3-0.5mm. Measurement results of 6.5wt%Si alloy samples produced by chemical vapor deposition (CVD) and powder rolling processing (DPR), and 3wt%Si grain oriented steel are compared with samples prepared by laminar composite technique.
Insertion versus Growth of Magnetic Nanoparticles in MgB2 Superconducting Composites
Authors: Sandu Viorel , Aldica Gheorghe , Badica Petre , Kuncser Andrei , Hayasaka Yuichiro
Published: June 2014

MgB2-based superconducting composites with magnetic nanoparticles were fabricated by spark plasma sintering technique. Two methods have been used to create nanoparticles within MgB2 matrix: i) direct insertion of passivated magnetic nanoparticles; ii) growth of magnetic nanoparticles by thermolysis of polymers or metallo-organic precursors. These composites display an enhanced critical current density due to the additional magnetic pinning generated by the magnetic interaction with the flux lines.
High Density Dislocation and Magnetoplasticity in Nano-Sized Alumina Reinforced 7055Al Composites Subject to High Magnetic Field
Authors: Li Guirong , Wang Hong Ming , Li Pei Si , Zheng Rui , Li Yue Ming , Cui Yu Hua , Peng Cong Xiang , Zhao Yu Tao
Published: June 2014

Nanometer Al2O3 particles reinforced 7055Al composites were processed by high magnetic field with 2T,3T and 4T magnetic induced intensity (B) with constant 30 pulses. Transmission Electronic Microscopy (TEM) and X ray diffraction (XRD) were mainly used to analyze some characteristic of the treated samples. The results show that with the increase of B the dislocation density was enhanced apparently. It is deduced that plastic deformation was the main reason of high density dislocation. The magnetoplasticity effect was the source of plastic deformation.
Effect of Carbon Nanotubes on Microstructure of Multiphase Composite Al2O3 Ceramics
Authors: Li Xiao Qing , Fang Bin , Xu Ming
Published: June 2014

In this paper, multiphase composite Al2O3 ceramics including carbon nanotubes was fabricated by hot pressing sintering. And researching and analyzing the influence of different volume fraction of carbon nanotubes for the microstructure of multiphase composite Al2O3 ceramics by SEM.
Research on Surface Modification of Nano-TiO2
Authors: Hao Xi Hai , Xiao Ying Zhe
Published: June 2014

Different surfactants such as Triethanolamine, Sodium dodecyl sulfate (SDS), and Polyvinylpyrrolidone (PVP) are applied in surface modification of nanoTiO2. The dispersion of nanopowder processed with different surfactants in water is evaluated using settlement method, in order to make more even composite films. The result shows that dispersion effect will be better when Triethanolamine is combined with the other two types of surfactants than only single type of surfactant is used. The best surfactant for dispersing nanoTiO2 is the mixture of Triethanolamine and Sodium dodecyl sulfate with mass ratio of 2:1 and 30% of surfactant amount; the experiment condition is set as both stirring and ultrasound times are 15 minutes, the initial settlement time of nanoTiO2 is set as 2.5 hours, and the total settlement time is set as more than 120 hours.
Dispersion Stability of Hydroxyapatite-Calcium Phosphate Glass Ceramic-Tertiary Butyl Alcohol System
Authors: Kim Dong Hyun , Yoon Seog Young , Park Hong Chae
Published: June 2014

The sedimentation bulk density and rheology of tertiary-butyl alcohol (TBA)-based hydroxyapatite/calcium phosphate glass ceramic suspension system have been examined in terms of oxide solid loading (10, 15 vol.%), and types of additives (dispersant, dispersant/gelator, dispersant/gelator/surfactant), and calcium phosphate glass ceramic content. Sedimentation density of hydroxyapatite decreased by adding calcium phosphate glass ceramic mainly due to the coarse and hence low surface area of calcium phosphate glass ceramic powder; the decrease effect was nearly offset when the dispersant was added. The suspension viscosity generally behaved in an opposite manner to the sedimentation density. A shear thinning rheology was shown in applied shear rate, regardless of processing variables.
Sintering Behavior of Lead Oxide Ceramic Prepared by Microwave Sintering
Authors: Ma Yan , Zhang Shu Yu , Xu Yan Ze , Lu Chen Lin
Published: June 2014

The structure material corrosion in liquid lead or lead-bismuth eutectic (LBE) is a tremendous limitation of the development of lead cooled fast reactors and accelerator driven sub-critical system (ADS). Keeping a certain oxygen concentration can prevent the steel pipe from corrosion by LBE. Through dissolution and precipitation of PbO ceramic has been found to control the oxygen concentration successfully. This paper presents research on a new technology of processing lead oxide ceramic. The raw material, pure lead oxide powder and deionized water, without any other chemical substances, were dry-pressed, placed in sample holder and heated in household microwave oven. Compare with conventional sintered ceramics, the microwave sintered lead oxide ceramics show better density, greater hardness. The results show that this promising technique has distinguished characteristics of energy-saving, rapid processing and better hardness and microstructure.
Effect of Tb4O7 Doping on Wear Resistance of High-Alumina Ceramic
Authors: Hu Cheng , Wu Bo Lin
Published: June 2014

It was investigated that the effect of wear resistance of high-alumina ceramic with a series of Tb4O7 additives. It showed that wear resistance of ceramic firstly increased and then decreased with increasing of Tb4O7 doped. And we found that microscopic played the vital role to affect wear resistance of alumina ceramic, decreasing grain sizes would improve the wear resistant. Terbium ions dissolved in liquid phases and the second phase of Tb3Al5O12 appeared would improve microscopic of ceramic, taken grain sizes small and made ceramic density. Doped 0.2wt% Tb4O7, alumina ceramic with small grain sizes had better wear resistance than other ceramic.
Effect of Calcite Content on Firing Characteristics and its Sintering Properties of Nixing Pottery
Authors: Zeng Xiao Le , Lu Shi Qiang , Zeng Jian Min , Hu Zhi Liu , Cao De Guang
Published: June 2014

According to the characteristics that purple red of nixing pottery contains an amount of calcite; different samples were fired with different content of calcite in the mud and varying temperature under oxidizing conditions. The phase composition and microstructure were analyzed. The results show that number and size of pores in the sintered samples increased and pore morphology changed from irregular closed hole to round closed then converted to irregular inter-connected one along with the increase of calcite content. As calcite content in the mud increases the viscosity of liquid phase decreases while the crystalline phase gradually increased as sintering, thus wollastonite phase transformed into eutectic phase of aluminum scapolite and wollastonite, and quartz content gradually reduced. Higher sintering temperatures and content of calcite were helpful to the reduction in viscosity, as calcite content increased gradually, the amount of liquid phase increased at first then decreased.
A Life Prediction Model for LEDs Lamps Based on the Thermal Life Theory
Authors: Huang De Zhong , Wu Ji Hua , Xu Guo Yong , Ruan Feng , Zhao Xiao Bao , Wang Guo Hua
Published: June 2014

The photometric, electrical, thermal and life features of LEDs are highly dependent on each other. All these factors should be considered together in order to optimize the operating point of LEDs. A thermal life theory about LEDs is developed. This theory shows the inner inks among photometric thermal and 1ife features of a LED. A life prediction model of LEDs and the relationship between output luminous flux and lifetime was found out by this theory. The life of LEDs can be predicted and find the proper operating point, at which the LED will generate the maximum amount of luminous flux in its total life cycle.
Research on the Mechanism and Model of Contact Resistance
Authors: Zhou Hao , Ji Qing , Jiang Pei
Published: June 2014

Study on contact resistance is a fundamental content of electrical contact field. The causes of contact resistance are complex, and a reasonable theoretical model poses significant impacts on the study and practical application of contact resistance. This paper describes the generating mechanism and components of contact resistance, highlights the summary on the development of the model, and gives the calculation method of contact resistance in practical engineering application.
Test Systems for Life of LED Light Based on Junction Temperature
Authors: Huang De Zhong , Wu Ji Hua , Xu Guo Yong , Ruan Feng , Zhao Xiao Bao , Wang Guo Hua
Published: June 2014

In order to predict the life of white LED in a short time, three groups constant stress accelerated life tests were conducted by increasing the working current. Life information of LEDs was obtained by using bilinear regression method. The numerical results indicated that the scheme of the accelerated life tests was correct and feasible. The estimation of the LED life was accurate by acceleration parameters．
The Effect of Mixed RE Elements on Microstructure and Mechanical Properties of Die-Cast AZ91D Alloy
Authors: Yuan Jia Wei , Li Xing Gang , Zhang Kui , Li Yong Jun , Ma Ming Long , Shi Guo Liang , Li Meng
Published: June 2014

The effect of mixed RE elements (Y, Nd, Gd ) on the microstructure and tensile properties of die-cast AZ91D alloy were investigated. The results indicated that the content of mixed RE elements lead to the change of the formation of Al▔RE compounds and reduction of the fraction of β-Mg17Al12 phase. The grain size of the alloy added 1.0wt. % RE became smaller than die-cast AZ91D and AZ91D+2.0wt. % RE alloys. The UTS of die-cast AZ91D+xRE(x=0 wt. %, 1.0wt. %, 2.0 wt. %) alloys were 204MPa, 194MPa, 203.6MPa at room temperature, respectively. Moreover, RE addition resulted in fracture behaviors changed.
Effect of Temperature on LiMn2O4 Prepared by Molten-Salt Combustion Synthesis
Authors: Li Bin , Xiang Ming Wu , Zhang Zhi Fang , Huang Ji Jun , Bai Hong Li , Liu Gui Yang , Guo Jun Ming
Published: June 2014

Spinel LiMn2O4 was prepared by a molten-salt combustion synthesis using eutectic acetate salts as starting materials without any additional molten-salt at 400°C, 500°C, 600°C and 700°C for 3h. The experimental results show that the main phase of the produts is spinel LiMn2O4, and the impurities are Mn2O3 or Mn3O4. It has been found that elevated temperature was easy to generate Mn3O4, and low temperature was easy to generate Mn2O3. The product prepared at 600 °C is single phase LiMn2O4 and has good crystallinity. With increasing combustion reaction temperature, the particle sizes of the products were decreased. The product prepared at 600 °C has the highest initial specific capacity of 116.5 mAh•g-1 at 0.2C, the capacity retention was only 77.2% after 50 cycles.
Electrochemical Title Performance of LiMn2O4 Synthesized by Flameless Solution Combustion with Acetate System
Authors: Zhong Lei , Xiang Ming Wu , Li Bin , Zhang Zhi Fang , Su Chang Wei , Bai Hong Li , Guo Jun Ming
Published: June 2014

LiMn2O4was synthesized by flameless solution combustion at 600°C for 3 hours (h). The influence of HNO3on the morphologies, crystal structure and electrochemical performances of the material was investigated. The results show that the main phase of all synthesized products is LiMn2O4, and the impurities are Mn2O3or Mn3O4depending on the concentration of HNO3(CHNO3). While CHNO3=0 and 15 mol L-1, the impurity was Mn2O3, when the concentrations of HNO3from 3 to 9 mol L-1, the impurity was Mn3O4; at CHNO3=12 mol L-1, the synthesized product was single phase; CHNO3≤12 mol L-1, with the increase of CHNO3, particles size grew from 70-130 nm to 140-500 nm, however, CHNO3is up to 15 mol L-1, particles become small (70-140 nm); the single phase of LiMn2O4obtained the maximum first discharge capacity (119.7 mAh g-1) at CHNO3=12 mol L-1, but its retention rate was undesirable, while CHNO3=15 mol L-1, the cycling performance of the product was the optimum with first discharge capacity of 118.5 mAh g-1and capacity retention of 90.9 % after 40 cycles at 0.2 C.
Research on Bonded NdFeB Arc-Magnets
Authors: Qin Wan Zhong , He Jie
Published: June 2014

The manufacture technology and mould structure of bonded NdFeB arc-magnets from press molding were described. The effects of the content of binder and additives, particle size of magnetic powder, the molding pressure, the treatment of magnet surface on the mechanical property, processing property, magnetic property and anti-oxidation property of press molding magnets were investigated. The press molding bonded magnets were prepared by using the MQP-B rapidly quenching NdFeB magnetic powder and epoxy binder. The magnetic properties are: Br = 0.722 T, Hcb = 457 kA/m, Hci = 718 kA/m, and (BH) max = 83.5 kJ/m3.
A PbS/ITO/Glass Based Photoelectrochemical Cell with a Sponge-Like Surface Structure
Authors: Yin Zhi Feng , Wang Peng , Fan Li Bo , Chen Zi Fa , Xu Shuo Lu
Published: June 2014

A photoelectrochemical (PEC) cell was made by a conventional three-electrode system. The working electrode was an as-prepared PbS/ITO/glass composite by a chemical bath deposition (CBD) method. The as-deposited films were characterized for structural, morphological, compositional and PEC properties. The X-ray diffraction (XRD) studies reveal that the films are polycrystalline in nature with cubic phases. The surface morphology was determined by scanning electron microscope (SEM) measurements. The film shows p-type conduction mechanism. The PEC cell, with PbS/ITO/glass as a photo cathode and Na2SO4 (0.10 M) solution as an electrolyte, was constructed and investigated for various cell parameters.
Photoionization in GaAs Photoconductive Semiconductor Switches
Authors: Liu Hong , Zheng Li , Yang Wei , Wang Xiao Qian , Dai Song Hui , Zhu Xiao Ling , Yang Hong Jun , Wu Dan
Published: June 2014

The density distribution characteristics of non-equilibrium carrier from spontaneous emission ahead of the tip of the current filaments in high gain semi-insulating GaAs photoconductive semiconductor switches are analyzed. The results show that the ratio of volume to area of the current filament and the average carrier density in the current filaments are two key factors that affect the photoionization effects of the current filaments. The reabsorption of wavelengths λ ≤ 876 nm radiations plays a dominant role in producing the maximum carrier density. The maximum density of photo-generated carrier is approximately 1~3 orders of magnitude lower than the average density of excess carrier inside the current filaments.
Research and Implementation on Methods of Evaluating Lifetime of LED Light Source for LED Lighting System
Authors: Wang Rong , Ma Hai Bo , Qu Bin
Published: June 2014

This research adopts comprehensive evaluation to evaluate lifetime of LED light source for lighting system. By the method, under the condition of LED light source working outside, the situations of LED light source lifetime are analyzed with attenuation rate of illumination got from illumination data of LED light source in practical work. The real lifetime characteristics and real life curve of the LED light source are obtained eventually.
Fabrication and Lead Ion Removal Property of Magnetic Hydroxyapatite Composite with Hierarchically Urchin-like Microstructure
Authors: Sun Rui Xue , Long Jia , Sun Zhen Zong , Li Chang Qiu , Wang Long Shan , Zhang Hong Xin , Chen Ke Zheng
Published: June 2014

The hierarchically urchin-like magnetic hydroxyapatite (HAp)/Fe3O4 composites were hydrothermally fabricated and were used for the removal of Pb (II) from aqueous solutions. The morphology, composition and properties of the magnetic HAp/Fe3O4 composites were fully characterized and investigated. The results showed that the HAp/Fe3O4 composites had a 3D urchin-like hierarchical structure with Fe3O4 nanoparticles dispersed among the building units. These urchin-like composites had high surface area and good magnetic responsibility. The equilibrium removal process of Pb (II) by the composites was correlated well with the Langmuir model, resulting in the maximum adsorption capacity of 223.71 mg/g. The high adsorption capacity and good magnetic responsibility suggest that the multifunctional composites have great potentials for heavy metal ion removal.
Study on Microwave Absorbing of Tourmaline and Dravite/ZnO Complex Powders
Authors: Zhang Xiao Hui , Ma Hong Wen
Published: June 2014

The complex permittivity and permeability of Dravite, Elbaite, ZnO and Dravite/ZnO complex powder are analyzed in this paper. Within the frequency range of 2~18 GHz, the dielectric losses of these four materials are in the sequence of: 0 ≈ Dravite ≈Elbaite < ZnO < coated powder = 0.211. The complex powder's magnetic loss decreases gradually with the increase of frequency. The magnetic loss is between 0.05 and 0.15 at the frequency ranging from 2 to 6 GHz. The research has shown that Dravite/ZnO complex powder exhibits some microwave absorbing capability, which may widen the application of tourmaline in the field of environmental depollution.
Modelisation of Permeability as a Function of Induction and Temperature by the Brillouin’s Function for the Formalization of the Magnetothermal Problem
Authors: Merouane Boudjemaa , Sebbani Mohamed
Published: June 2014

In induction heating, one is often brought to solve the system of coupled equations:Thermal physical caracteristics (calorific capacity and thermal conductivity.) and electromagnetic (permeability, susceptibility, reluctivity, permittivity, electric conductivity) depend on the temperature for the first, the temperature and the magnetic or electric field for the seconds.The modelisation of the permeability according to the only applied field magnetic abounds in the scientific literature. But, its modelisation as a function of the applied field and also temperature is rather rare.The goal of this work is thus to establish this double modelisation.In this intention, we will use the heat equation, the Maxwell's equations and the function of Brillouin, wich is the physical and formally basis of this modelisation.
Finite Element Analysis of Dynamic Splitting Tensile Mechanical Properties of Reinforced Concrete
Authors: Song Xiao Yan , Zhang Pei Wen
Published: June 2014

Finite element analysis is carried out on the dynamic splitting tensile mechanical properties of reinforced concrete with LS-DYNA. The impact of strain rate and reinforcement ratio on the dynamic tensile strength and failure mode of reinforced concrete is considered in the calculation. The result shows that the form of reinforcement and reinforcement ratio has a greater impact on the failure mode and tensile strength of concrete. The dynamic splitting tensile strength of reinforced concrete has a certain strain rate effect and its splitting tensile strength increases with the strain rate; the splitting tensile strength of reinforced concrete also increases with its reinforcement ratio.
Study of Model Tests on Large-Span Tunnel’s Damage Caused by Overload with Arch Cover Method
Authors: Ji Zhao Qi , Jia Yong Gang
Published: June 2014

In the process of large-span tunnel excavation by arch cover method, how to ensure the safety of construction and to reduce the influence on the surroundings and environment has arising wide attention of scholars both domestic and abroad. But now it is still in the stage of experience as to the rock pressure and its instability failure, especially to the research on rock overload damage. Regarding the large-span tunnel rock failure mechanism of progressive collapse by arch cover method, large-diameter modeling test are adopted to do systematical research on the rock failure phenomena as load increase. Determine its ultimate failure state by increasing vertical load, then we can get its failure characteristics and instability criterion in different rock support section.
Study on Moment-Curvature Hysteretic Model of Steel-Concrete Composite Box Beam
Authors: Jiao Chen Bei , Jiang Li Zhong , Huang Zhi
Published: June 2014

In this paper, by the finite element analysis software-ABAQUS, nonlinear analysis models of steel concrete composite beams under vertical low-cycle repeated load were simulated. The influence of seismic performance parameters, such as degree of shear connection, the ratio of height to thickness of the web were studied, and these parameters’ appropriate range were advised. According to the finite element analysis and test results, formulas of positive and reverse stiffness degradation, a trilinear model for moment-curvature hysteretic performance of simply-supported steel concrete composite beam were proposed.
Nonlinear Analysis of Concrete-Filled Steel Tubular Columns under Blast Loading
Authors: Cao Xue Ye , Li Yan , Zhao Jun Hai
Published: June 2014

The plastic ultimate moment of concrete-filled steel tubular and the ultimate displacement of the simply supported beam under uniformly distributed load is established based on unified strength theory. Considered nonlinear impact of mass and stiffness changed in the process of the reaction, the dynamic response of concrete-filled steel tubular columns under blast load were analyzed by the equivalent single degree of freedom model and step by step integration method. Compared the results of this method with relevant literatures, the consequence is good. It can be seen that from the results, this method was satisfied for the requirement of the analytical precision, it can be referred for the research and the safety of concrete-filled steel tubular columns under blast load.
Study on the Ultimate Bearing Capacity of Concrete Filled Steel Square Tubular Short Column with PBL
Authors: Ling Yun , Feng Wen Yu , Zhao Jun Hai , Li Yan
Published: June 2014

Aiming at the specific concrete filled square steel tubular short column stiffened with PBL under axial compression load, considering about the useful effect of the PBL shear connectors, the mechanical behavior of PBL stiffening ribs was analyzed. Through the analysis of the effective restriction-area and ineffective restriction-area of core-concrete, introduce into the effective constraint coefficient of concrete. The ultimate bearing capacity was deduced based on the unified strength theory, with some influencing factors analyzed as well. Compared with the test results in relevant documents, they coincided well with each other. The result shows that the formula which is deducted from the unified strength theory has good applicability and the solution will show its positive impact in the related fields.
Tests Results Strength and Thermophysical Properties of Aerated Concrete Block Wall Samples with the Use of Polyurethane Adhesive
Authors: Grinfeld G. I. , Gorshkov Alexsandr S. , Vatin Nikolay I.
Published: June 2014

This article deals with the strength and thermophysical test results made on the basis of the masonry samples of cellular autoclave curing concrete (aerated concrete blocks) with the use of polyurethane adhesive. Aerated concrete masonry walling with the use of polyurethane adhesive is indicated herein to be technologically feasible and economically viable. The major advantage of the masonry option under consideration lies in the following aspect: thermal conductivity of polyurethane adhesive used to fasten aerated concrete blocks in masonry walls is significantly less than thermal conductivity of concrete adhesives and mortars. For this reason, thermal insulation properties of the masonry with polyurethane adhesive appear to be better comparatively to the block masonry made with the usage of concrete adhesives of any other type. On the ground of the tests conducted the following was resumed: it is acceptable to carry out masonry works with the use of aerated concrete blocks and polyurethane adhesive in construction of exterior and interior nonbearing walls provided appropriate justifying calculations are made.
Current Status and Development Trend of Assembled Structure in Cold Regions
Authors: Wang Ya Bo , Liu Han Ting
Published: June 2014

Based on the review of the history of domestic and foreign architecture, the necessity and urgency of industrialization in construction is expounded. According to the current status and problems of the assembled structure in severe cold region, the method is given. The feasibility analysis is done in the light of the comparatively example.
Highly Filled Building Materials Reduced Flammability
Authors: Gerasimovich Bruyako Mihail , Stanislavovna Grigorieva Larisa
Published: June 2014

This paper presents research on the development of technologies for highly filled building material of low flammability based on CMSW. An affordable and effective fire retardant. The studies assessing the effect of the proportion of components of the molding composition, compaction pressure when forming the product on the final properties of the material.
Modern Building Materials and the Concept of "Sustainability Project"
Authors: Gayevskaya Zlata Anatolyevna , Rakova Xeniya Mikhailovna
Published: June 2014

The term "sustainable development" came in to use in 20th century and can be regarded as the set of mind notion. The International Union of Architects by the Copenhagen Declaration (December 7th, 2009), noted that "the concept of sustainability project" recognizes that all architectural and urban objects are part of a complex interactive system linked to their natural environment" [1]. The search for modern energy efficient building materials and technologies should be linked to the energy-efficient landscaping and typological object organization. Proposed scientific method provides the criteria of "sustainability project" in terms of modern energy efficient building materials usage. The modern construction materials building projected method suggested to be the part of complex interactive system linked to its natural surroundings based on the object energy-efficient organization properties (architectural, landscape and typological).