bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation and Experiment Research on Aerodynamic Characteristics of a Multi-Blade Centrifugal Fan
Authors: Zhang Yong Chao , Chen Qing Guang , Zhang Yong Jian , Jia Xiang Xing
Published: August 2011

The full flow field model of a widely used multi-blade centrifugal fan was built, and unstructured grids were used to discrete the computational domain. The moving reference frame is adopted to transfer data between the interfaces of the rotating field and the stationary field. Pressure boundary conditions are specified to the inlet and the outlet. The SIMPLE algorithm in conjunction with the RNG k-ε turbulent model was used to solve the three-dimensional Navier-Stokes equations. The steady and unsteady numerical simulations of the inner flow in the fan at different working conditions were presented using the CFD method. The numerical simulation results were validated by contrasting to the experiment results. The results displayed the characteristics of the velocity field, pressure field, pressure fluctuation at two monitoring points in the centrifugal fan. The results can provide basis for optimizing the fan design and the internal flow, and have important value of engineering applications in the increase of the overall performance in operation.
Compressor Anti-Surge Control System Optimization Energy Saving Renovation
Authors: Cao Hui , Wang Chen , Lin Chang Ji
Published: August 2011

The original control system adopts MEH controller and maintains the operation of the unit by continually backflow. But surge problem still exists in the running, which constitutes a serious threat to the safety of the unit, meanwhile wastes a lot of energy. Later S5 Duplex control system of CCC Company is adopted in the reconstructed control system, which rebuilds the compression anti-surge control system, eliminates surge threat and huge energy consumption. Millions of profits can be created by this renovation each year. The targets of stable operation and energy conservation can be achieved as well.
Feasibility Analysis of Thermal Energy Recovery for the Shanghai Railway Station
Authors: Tong Zheng Ming , Liang Shu Jun
Published: August 2011

In recent years, China has focused on the research of energy reuse and environmental protection with lots of manpower and financial capacity. And we have already gotten results on many aspects from transportation to factory production. In this paper, we will think about energy reuse from a new perspective: recovery and reuse of heat energy of human body. This paper researches and analyses the feasibility of thermal energy recovery for the shanghai railway station.
History’s Continuity and Regeneration of Fangzi, a Modern Town along Jiaoji Railway
Authors: Zhu Xiao Lin , Liu Juan , Ju Hong Lei
Published: August 2011

Fangzi, a century town, born because of Jiaoji Railway , still retains the old style, showing unique town layout and the historical and cultural landscape as a modern industrial town along the Jiaoji Railway, preserved basic integrity of the modern German-style architecture. In recent years, as urban development, adjustment planning of urban industrial layout, Fangzi, as the representative of industrial and mining town is facing a crucial decision. This paper through the understanding of the process of formation and development of Fangzi, urban pattern and architectural style, from the angle of science, history, art, culture to made the value research, and finally to identify strategies to protect and re-use, in the meantime, provide reference for the same type towns.
Control Methods of Active Power Filter
Authors: Ma You Jie , Zhao Jian , Zhou Xue Song
Published: August 2011

Active power filter (APF) is an important device to compensate harmonic and reactive current in power system control method adopted has a great influence on its performance. The paper introduces several control methods used by APF, including the deadbeat control, single-cycle control, space vector control and so on. After comparing and analyzing their individual advantages and disadvantages, some improvements for APF performance are proposed.
Second Order Model Reduction Based on Diagonal Blocks of Gramians
Authors: Teng Cong
Published: August 2011

In this paper, some new algorithms based on diagonal blocks of reachability and observability Gramians are presented for structure preserving model order reduction on second order linear dynamical systems. They are more suitable for large scale systems compared to existing Gramian based algorithms, namely second order balanced truncation methods. In experiments, they have similar performance as the existing techniques.
Study on Preparation and Factors of Amino Silicone with Low Viscosity
Authors: Lei Yuan Yuan , Zheng Guo , Sun Yu , Zhou Yong
Published: August 2011

Amino silicone (PDMS) with lower viscosity were synthesized at a certain temperature by ring opening copolymerization of octamethylcyclotetrasiloxane (D4), N-β-aminoethyl-γ- aminopropyl methyl dimethoxysiloxane (YDH-602), hexamethyldisiloxane (MM) with KOH as catalyst and DMSO as accelerating agent. The chemical structure was characterized via IR and 1HNMR. And the important factors were investigated carefully and the best technology of synthesis was obtained: reaction temperature 100-110°C, time 3h, KOH 0.05%, DMSO 0.5% and MM 5-7%, distilling at 110°C/0.095Mpa for 40 min.
Optimizing Design and Application of BP Neural Networks Based on Genetic Algorithm
Authors: Niu Wang Jie , Qu Er Guang , Liu Chun Yan
Published: August 2011

Genetic algorithm optimize weight’s volume of Neural Networks by optimizing learning rate and inertia coefficient, which overcome the BP algorithmic shortcoming of easy into the part extreme, and have ensured BP algorithmic training accuracy, and makes it have higher self-adaptability and self-learning ability.
Robust Control with Input-Output Decoupling Technique for an Interior Permanent Magnet Synchronous Motor in Electrical Vehicle System
Authors: Lin Li , Tang Hong Wei , Tang Jie
Published: August 2011

A new interior permanent magnet synchronous motor (IPMSM) control method is presented for electrical vehicle drive system. Based on the differential geometry theory, the nonlinear system is changed into a linear system with input-output decoupling technique. Then, by the maximum torque per ampere (MTPA) control strategy, the output torque of the drive system is added. And then, a load torque observer is designed to resist the variable load. In the end, Based on the linearization model, an controller is given. Simulation results show that the electrical vehicle drive system based on decoupling robust control has fast transient responses, good load disturbance resistance responses and good tracking responses.
Prediction of Liquid Viscosity Effect on Flow Field and Performance in a Solid-Liquid Hydrocyclone
Authors: Feng Ding , Huang Si , Luo Li , Ma Wei Guo
Published: August 2011

Many factors can have effect on flow field and performance, which makes the hydrocyclone design a complex work. Liquid’s viscosity is one of these factors, but it is costly and almost impossible to investigate how the liquid viscosity influences the performance of the hydrocyclone by test or experiment. At present, CFD technique provides us a convenient method for the flow field research in the hydrocyclone. This paper, intended to explore the effect of liquid’s viscosity on the flow field and hydrocyclone’s efficiency, presents a simulation to model the flow field in the hydrocyclone by changing the viscosity of the liquid. By comparing the results of the simulation, it is found that liquid with higher viscosity can reduce the velocity of the flow because of the friction between flow and wall and the friction between the two phases. Furthermore, viscosity increase of the liquid enlarges the area of shot flow and circulating flow, which make separating efficiency decrease and energy consumption rise.
Research on the System of Lighting Energy Conservation in Public Places
Authors: Liu Hui Wen , Wu Han Shui , Zhao Xue Zheng
Published: August 2011

To response the call of “constructing an economical society” and saving electricity consumption of public places, this paper designs an automatic control system of lumination in public places based on time, lighting intensity and personal distribution etc. It’s in low price that it is equivalent to a manual switch. Moreover, it’s low energy consumption, with steady performance, convenient installation without changing original line.
Effect of Impact Load on Transient Elastohydrodynamic Lubrication of Spur Gears
Authors: Wang You Qiang , He Zhi Cheng
Published: August 2011

A full transient elastohydrodynamic lubrication(EHL) solution of involute spur gears is obtained under impact load based on the multi-grid (MG) method for solving the pressures, the multi-level multi-integration (MLMI) approach for evaluating the elastic deformations, which takes into account the variation of equivalent curvature , entertainment velocity and load on time along the line of action, the gear tooth surface is assumed to be smooth. The influences of impact load spectrum and the approach impact load when the teeth come into action on the EHL pressure and film thickness are analyzed in the paper. The results show that the approach impact load can strongly influence the approach point maximum pressure and minimum film thickness. The impact load can lead to instantaneous lubrication film deterioration between contact teeth of involute spur gears. The maximum pressure and the minimum film thickness all occur in the vicinity of approach point immediately after the impact load was feed. The approach impact load is seriously harmful to the gear lubrication.
Vibration Control Performance of Active Mount System Featuring Inertial Piezostack Actuator
Authors: Oh Jong Seok , Choi Seung Bok , Nguyen Vien Quoc , Moon Seok Jun , Choi Sang Min
Published: August 2011

This paper proposes an active mount of naval ships in order to reduce unwanted vibrations. The active mount consists of rubber element and piezostack actuator. To avoid being broken piezostack actuator, the inertial actuator which the piezostack actuator is connected to the inertial mass and rubber element is devised. After describing the configuration of the mount, the active mount system supported by four mounts is then constructed. To attenuate the transmitted vibrations, the feedforward control is designed and experimentally implemented to the system. Vibration control performances such as vertical accelerations are evaluated at each mount and presented in frequency domain.
Study of EV Motor Control Scheme
Authors: Yan Shi Rong , Li Shi Zhong
Published: August 2011

According to electrical vehicle (EV) working requirements, a built-in permanent magnet (IPM) synchronous motor is selected as the topic motor. A mathematical model about the motor is described here. To make the EV run smoothly, safely and economically, two control loops for the electric motor are developed. One is based on motor current control, which consists of maximum torque per ampere control and field weakening control. Other is motor speed control loop, in which a sliding mode control (called a variable speed exponential reaching law) is used. Through simulation study, the control scheme developed here can make the motor work well, which means it can be used in some EV driving systems.
Multi-Objective Optimization of a 2-DoF Purely Translational Parallel Manipulator
Authors: Li Zhi Bin , Lou Yun Jiang , Zhang Yong Sheng , Li Ze Xiang
Published: August 2011

The paper addresses the multi-objective optimization of a 2-DoF purely translational parallel manipulator. The kinematic analysis of the Proposed T2 parallel robot is introduced briefly. The objective functions are optimized simultaneously to improve Regular workspace Share (RWS) and Global Conditioning Index (GCI). A Multi-Objective Evolution Algorithm (MOEA) based on the Control Elitist Non-dominated Sorting Genetic Algorithm (controlled ENSGA-II) is used to find the Pareto front. The optimization results show that this method is efficient. The parallel manipulator prototype is also exhibited here.
Longevity Study of the Head of Hammer Crusher
Authors: Lin Jian Dong , Huang Ping , He Fan
Published: August 2011

Aiming at the poor condition of high chromium casting iron hammerhead longevity, developing high vanadium casting iron hammerhead, producing it by metal mould, and passing more than 10,000 tons production testing.
Computer Aided Geometric Method of Forward Kinematics Analysis of Multi-Legged Walking Robots
Authors: Wang Liang Wen , Tang Wei Gang , Wang Xin Jie , Chen Xue Wen
Published: August 2011

The high order equation causing by analytic method in multi-legged robot forward kinematics analysis may have imaginary root, repeated root, extraneous root or even lost solution. A system based on the theory of computer aided geometric method is proposed. Consideration with the internal structural constraint relations of multi-legged walking robots, the solidworks model was constructed and Visual Basic develop platform was adopted to fulfill the secondary development of solidworks. A system of forward kinematics analysis of multi-legged walking robots is established. The example validates that the system is simple and effective for all reptiles-like quadruped walking robot.
Complete 3D Modeling from Rotational Devices
Authors: Chen Sheng Yong , Liu Da Wei , Wang Xiao Yan , Huang Wei , Guan Qiu
Published: August 2011

For acquisition of complete 3D models, this paper uses a rotational device to capture a set of image sequences. A direct projective reconstruction method is proposed by linear transformation, which can avoid getting corresponding points in more than two images. Actually, projective reconstructions are obtained from two neighboring images and the reconstructions are combined with the common 3D points. Finally, all reconstructions are merged into the initial one to construct a complete model. Several practical experiments have been carried out to validate the accuracy of the method.
Applications of Visible and near-Infrared Hyperspectral Imaging for Non-Destructive Detection of the Agricultural Products
Authors: Jiang Ying Lan , Zhang Ruo Yu , Yu Jie , Hu Wan Chao , Yin Zhang Tao
Published: August 2011

Agricultural products quality which included intrinsic attribute and extrinsic characteristic, closely related to the health of consumer and the exported cost. Now, imaging (machine vision) and spectrum are two main nondestructive inspection technologies to be applied. Hyperspectral imaging, a new emerging technology developed for detecting quality of the food and agricultural products in recent years, combined techniques of conventional imaging and spectroscopy to obtain both spatial and spectral information from an objective simultaneously. This paper compared the advantage and disadvantage of imaging, spectrum and hyperspectral imaging technique, and provided a description to basic principle, feature of hyperspectral imaging system and calibration of hyperspectral reflectance images. In addition, the recent advances for the application of hyperspectral imaging to agricultural products quality inspection were reviewed in other countries and China.
Serial-Parallel Combined Distributed Algorithm For High Speed Sampled Data Filter of Sensor Signal
Authors: Xie Bao Zhong , Chen Tie Qun
Published: August 2011

Distributed Algorithm (DA) has been applied widely because it doesn’t need multiply operation. The serial structure DA takes less chip resource but more calculation time, while the full pipeline parallel structure DA is just the reverse. A Serial-Parallel combined DA is proposed in this paper to take full advantages of the above structures to realize sampled data filter from sensor signal. Through the verification by simulation and synthesization, it is shown that the proposed improved serial-parallel DA can realize real time high speed sampled data filter from sensor, and it can reach the best tradeoff of time and chip area.
Effect of Laser Hardening Parameters on the Valve Seat of Worm Cast Iron
Authors: Pang Ming , Li Hui , Tan Jian Song , Xu Guang Hui , Zhang Quan Zhong
Published: August 2011

Exploring experiments of the laser hardening valve seat of worm cast iron were conducted.Microstructure of laser hardening region was characterized by optical microscopy (OM). Mechanical properties of the hardening region were evaluated by hardness. Effect of laser hardening parameters on the valve seat of worm cast iron were discussed in detail. Results show that the harded region have non-equilibrium microstructures consisting of martensite and residual austenite with a little ferrite. Microstructure of the martensite shell around the worm graphite in the hardened zone is observed. With increasing defocusing distance ,the hardness of hardened region decrease.The hardness of hardened region can be increased by imporving laser power and reducing laser welding velocity.
Synthesis and Characterization of SiO2/ZnO Core-Shell Spheres
Authors: Tseng Yung Kuan , Wang Pei Han , Su Shun Lung
Published: August 2011

This Study applies to Stöber method for synthesis an characterization of even-sized SiO2micrometer sphere; and then applies to sol-gel method for encapsulation for one layer of ZnO at SiO2spherical surface after regarded it as core so that synthesis SiO2/ZnO core-shell spheres successfully. And observe morphology by FE-SEM and crossection by TEM. The TEM specimen were cut by two-beam FIB. Besides, EDS, XRD and UV-Visible spectroscopy were using for the analysis of composition, crystallization structure, and absorption spectrum, respectively. Experimental results showed that, SiO2spherical surface became smooth after deposition for zinc oxide. The specimen made by FIB more obviously was observed for core-shell distribution by TEM. EDS analysis made us clearly see shell signal with ZnO content, but core signal only is SiO2content. XRD analysis indicated its core-shell sphere signal possessing ZnO content, but UV-Visible absorption spectrometer displayed ZnO has been absorbed in range of UV light, in contrast, it is not absorbed in range of visible light.
Transportation Risk Assessment of Hazardous Chemicals Based on Risk Rank
Authors: Liu Li Ping , Liu San Hua , Li Shu Xia
Published: August 2011

Research on hazardous chemicals transportation risk assessment has very important significance not only for security of life and property but also for improvement of social environment. This paper reviews literatures of transportation risk assessment. On this basis, transportation assessment model of hazardous chemicals is presented considering probability of risk magnitude and the measurement of loss. Then corresponding transportation assessment process based on risk rank of hazardous chemicals is given.
FEA Analysis and Monitoring of Long-Term Behavior of an Insulation Block from Recycled Polymer HDPE
Authors: Pěnčík Jan , Matějka Libor
Published: August 2011

Use of waste materials is an actual topic that corresponds to current trends associated with the decreasing of power exigency and sustainable development. The possibility to reduce depletion of natural resources and decrease the produced waste lies in an efficient and possibly repeated use of resources. An important subgroup of waste is formed by materials from petroleum derivatives - polymers (PP, PE, HDPE etc.). Polymers and their composite materials can be used as a base material for most products including products used in civil engineering. One of these products is an insulation block for elimination of thermal bridges in wall footing. During design of this product the MAP method (modelling-analysis-prediction) has been used together with experimental testing. This paper deals with the description of long term behaviour of an insulation block made of recycled polymers using full scale testing. Experimental data is compared to different rheological models.
Primary Study of Wear-Resistance Characters of the Recycled Composite Materials
Authors: Feng Zhi Ming , Song Yan Pei , Zhao Zhen Kai
Published: August 2011

Study of wear-resistance of recycled composites matrix preparated by means of remelting and centrifugal casting to waste composites is conducted under Low speed and different load. The results show that wearability of recycled composites matrix are higher than that of the primary composites matrix and high-Cr cast iron,it reveals that recycled composites matrix has better wear-resistance properties. with the increase of load,the friction coefficient decreases,and wear rate increases.wear mechanisms of recycled composites matrix are susceptible to load,wear mechanisms of recycled composites samples are mainly adhesion wear in low load condition, and with the load increased, wear mechanisms are mainly the plastic formation wear, plowing wear and oxidative wear.
Study on Coarse Aggregate Gradation Analysis of Cement Treated Base Course Based on Core Sample Image
Authors: Hu Li Qun , Wang Chao Fan
Published: August 2011

In order to get the coarse aggregate particle gradation of cement treated base course core sample dilled form the pavement, an image acquisition system is designed. The system mainly contains an Aviiva ® M2 CL line scan camera, a core sample rotation platform and a LED light source. The software are designed and implemented by using the Matrox Mil controls in the Visual Studio VB.NET. Test results show that when the camera exposure time is set to 800μs, good quality image of core sample can be obtained. In the study, the original core sample images of cement treated aggregate were improved by rescaling of each pixel, then were binarized by using adaptive threshold method. After getting the binary image, morphological operations were carried out to deal with the conglutinations of the particles. Next, characteristics of each particle, such as area, perimeter, fitting ellipse and minFeret were extracted to calculate the area passing rate of aggregate with different size. Results shows that, in this way, the gradation of coarse aggregate (>2.36mm) can be got and the method helps to get the coarse aggregate particle distribution of cement treated aggregate core sample quickly.
Determination of Moisture Content in Ginger Using PSO Combined with Vis/NIR
Authors: Li Jing , Xue Long , Liu Mu Hua , Lv Ping , Yan Lin Yuan
Published: August 2011

Vis/NIR spectroscopy was used to measure the moisture content of ginger. 330 samples were separated into two groups, as training and validation. Vis/NIR reflection spectral data from 350 to 1800 nm were collected using ginger within the training and validation sets. PSO was used to establish the PLS model. In comparison to the full spectrum model (contained 1451 variables), the prediction capability was improved after using PSO for PLS models. The number of selected variables and LVs were 300 and 6, respectively. The correlation of determination in validation set (), root mean square error of prediction (RMSEP), and bias by PSO-PLS were 0.9881, 4.7827, and 0.1751.
Design of Fault Diagnosis System for the Parameter-Depended Control System
Authors: Zhou Jing
Published: August 2011

A robust parameter-depended reduced order(RPRO) fault detection filter(FDF) is designed. Contrary to the parameter-depended uncertainty system, the order of the linear matrix inequalities is reduced, then the RPRO fault detection and fault isolated filters are constructed. Then a RPRO fault isolation filter is designed for occurrence of both actuator fault and sensor fault in the aerocraft’s closed-loop control system, and fault diagnosis system is structured based on the fault isolation filters. Through the output of the fault diagnosis system, we can alarm the fault timely and the advantages of this approach are highlighted.
Effect of γ-Radiation on the Property of Polypropylene/Nylon-6 Blends
Authors: Chen Jin Zhou , Wang Qian , Niu Ming Jun , Guo Kai , Li Xin Fa , Wang Jing Wu
Published: August 2011

Blends PP/PA (100:18) was prepared by means of melt-mixing using a twin- screw extruder, and the effects of γ-radiation in air on their stability under lower radiation dose (≤5kGy) at a fixed dose rate of 110Gy/min have been researched. The effects of nylon-6 (PA-6), trimethyrol-propane trimethacrylate (TMPTA), maleated polypropylene (mPP) and γ-radiation dose (D) on melt flow ability, mechanical property, thermal property and morphology of the blends were investigated. It was noted that its tensile strength (σs) and Young’s modulus (E) increased with the addition of TMPTA, while its elongation (ε) and melt flowing rate (MFR) decreased. Compatibilizer mPP and TMPTA could improve the compatibility of the PP/PA-6. Its heat resistance was superior to PP. There was little effect of γ-radiation in air on their σs, E and ε when irradiation dose ranged from 0.1 to 5.0kGy.
Numerical Simulation of Creep-Fatigue Crack Growth for Nickel-Based Super Alloy with Extended Finite Element Method
Authors: Zhang Guo Bin , Yuan Huang
Published: August 2011

Extended finite element method is widely used to simulate the discontinuity problems, e.g. fatigue crack growth. This paper mainly analyzes the fatigue crack propagation under elevated temperature in nickel-based super alloy with extended finite element method. Cohesive zone model is used to describe the mechanical behavior around the crack tip. A modified creep damage model is introduced. Fatigue damage and creep damage are accumulated in a linear relationship. And the results produced by computational code are presented and draw a comparison with experimental observation.
Laser Textured Black Silicon Solar Cells with Improved Efficiencies
Authors: Sedao Xxx , Torres Rémi , Sarnet Thierry , Delaporte Philippe , Sentis Marc
Published: August 2011

Femtosecond laser irradiation of silicon has been used for improving light absorption at its surface. In this work we demonstrate the successful implementation of femtosecond laser texturisation to enhance light absorption at Si solar cell surface. In order to adapt this technology into solar industry, the texturisation process is carried out in air ambient. The microstructure similar to what has been produced in vacuum can be made in air by using appropriate laser conditions. The texturised surface shows excellent optical properties with a reflectivity down to 7% without crystalline orientation dependence. Junction formation and metallisation proceeded after texturisation. Suns-Voc measurements are performed to evaluate the cell performance and decent electrical characteristics have been achieved.
Study on Three-Dimensional Fluorescence Spectra of Oil Concentration in Water
Authors: Wang Yu Tian , Yang Li Li , Lu Xin Qiong
Published: August 2011

According to the Lambert-Beer laws, the fluorescence spectra of oil in water were investigated by measuring excitation-emission matrixes with FS920 fluorescence spectrometer. On the basis of the three-dimensional fluorescence spectra of oil in water, the excitation wavelength of 290nm and emission wavelength of 324nm were chosen for the quantitative analysis of oil in water. The results show that the concentration of oil in water is linearly proportional to the fluorescence intensity in the range of 1ppm-100ppm, and the measurement model of concentration is obtained with the linear correlation coefficient of 0.9993. The artificial samples has also been tested and the results are satisfactory. The recovery is in the range of 92%-106%. The research provides experimental basis for the quantitative analysis of multi-component oil in water.
Carbon Black Conductive Composite Based Resistance-Temperature Measurement System Using AT89S51
Authors: Wang Juan , Lai Si Yu
Published: August 2011

AT89S51 microcontroller based carbon black conductive composite materials resistance-temperature measurement system is designed, which achieves the measurements of resistance and temperature with the help of thermocouple amplifier chip AD595. Describe the hardware and software design, especial the acquisition of temperature and resistance and the display process. The experimental results show that the system can easily and accurately measure the resistance and temperature and the metrical data validate the PTC properties of carbon black conductive composite.
Research on Adsorption Material for Organic Solvent Floating on the Water
Authors: Liu Gui Ling , Xia Xin , Wu Qing Bin
Published: August 2011

Based on short of effective disposal measure for organic solvent leakage, this paper developed a kind of styrene-divinybenzene copolymer that can absorb massive organic solvent such as benzene on the water, and it contains a great deal of benzene ring, has good hydrophobic and lipophilic property, what’s more, it has lower density than water and thus floating on the water before and after adsorption, easily separating from water, so it is a kind of perfect adsorption material of organic solvent like benzene at leakage case on the river. Besides, this paper discussed synthesis temperature, feeding proportion and water containing, obtaining optimal synthesis conditions, so max. adsorption amount for benzene on the water can be reached 25mg/l at this optimal conditions.
The Elasticity of Soybean Protein Fiber Blended Yarn
Authors: Yang Qing Bin , Gao Shou Wu
Published: August 2011

Abstract In order to describe the relation between the elasticity and the blended ratio of soybean protein fiber blended yarn, the elasticity of different kinds of blended ratio of soybean protein fiber/polyester and soybean protein fiber/cotton blended yarn was measured. The relation between the elasticity and the blended ratio of blended yarn is determined. The optimum blended ratio is analyzed.
Effect of Eutectic Reaction Induced by Pr on Microstructure in Semisolid A356 Alloy
Authors: Liu Zheng , Liu Xiao Mei , Hu Yong Mei
Published: August 2011

Semisolid A356 alloy, which is grain-refined by Pr, was prepared by low superheat pouring. The effects of grain-refined by Pr on the morphology and the grain size of the primary α-Al in semisolid A356 alloy are researched. The results indicate that semisolid A356 alloy with particle-like and rosette-like primary α-Al can be prepared by low superheat pouring from liquid A356 alloy grain-refined by Pr. The grain size and particle morphology of primary α-Al in A356 alloy are markedly improved by 0.3wt% Pr. The refining mechanism of Pr on the morphology and the grain size of the primary α-Al in semisolid A356 alloy were delved.
Stability of Material from Hydrothermal Humification of Biomass in Soil
Authors: Guo Shu Qing , Dong Xiang Yuan
Published: August 2011

hydrothermal humification (HTH) is a novel way to treat biomass in order to produce soil conditioner or organic fertilizer. The incubations were performed in about 200mL pots which were either filled with mixtures HTH material and soil (1:3, wt:wt).The several studies were carried out to investigate how HTH materials derived from lawn-grass, pine-branch, and pine-needle interact with existing organic matter in soils. Compared with natural soil, C/N and lignin residue changes of incubated materials were analyzed during incubation. The results show that although the C/N and lignin residue decreased across incubation, HTH addition hadn’t a significant effect on activity of microorganism, indicating a more efficient stability of HTH in soil.
Synthesis and Fluorescence Properties of New Europium (III) and Terbium (III) Complexes with N-(3-methoxyl–phenyl)ketoacetamide
Authors: Tai Xi Shi
Published: August 2011

Aβ-diketonate-type ligand, N-(3-methoxyl–phenyl)ketoacetamide (L), and its complexes with europium (III) and terbium (III) were synthesized. The ligand and complexes were characterized by elemental analysis, IR spectra,1HNMR spectra, mass spectra and luminescent spectra. The complexes were characterized by elemental analysis, IR spectra. The stoichiometry of metal-to-ligand in the complexes also was confirmed by the fluorescence behavior of the ligand and complexes in CH3CH2OH solution. In addition, the fluorescence properties of complexes in DMF, CH3OH, CH3CH2OH, acetone and CHCl3were investigated. The characteristic fluorescence of terbium (III) was assigned.
Application of CMAC Neural Network & PID Control on Hydraulic Speed Servo System
Authors: Tang Rui
Published: August 2011

Pointing on nonlinear and parameters vary with time in the velocity servo system, and the requirement of servo system is difficult to meet by the traditional PID control scheme. A control scheme of ANN-based PID controller is developed here for velocity tracking control for an electro-hydraulic velocity servo system. In this paper the mathematical model is established for the system, and the PID controller based on cerebellar model articulation controller (CMAC) are designed and connected in parallel. Numerical simulation results indicate that the proposed control scheme has an excellent performance on high precision velocity tracking ability and rejection of disturbance, comparing with conventional PID control strategy.
Hydrogen-Induced Dissociation of the Fe-B Pair in Boron-Doped P-Type Silicon
Authors: Tang Chi Kwong , Vines Lasse , Svensson Bengt Gunnar , Monakhov Eduard
Published: August 2011

The interaction between hydrogen and the iron-boron pair (Fe-B) has been investigated in iron-contaminated boron-doped Cz-Si using capacitance-voltage measurements (CV) and deep level transient spectroscopy (DLTS). Introduction of hydrogen was performed by wet chemical etching and subsequent reverve bias annealing of Al Schottky diodes. The treatment led to the appearance of the defect level characteristic to interstitial iron (Fei) with a corresponding decrease in the concentration of the Fe-B pair. Concentration versus depth profiles of the defects show that dissociation of Fe-B occurs in the depletion region and capacitance-voltage measurements unveil a decrease in the charge carrier concentration due to passivation of B. These quantitative observations imply strongly that H promotes dissociation of Fe-B releasing Fei whereas no detectable passivation of Fe-B or Fei by H occurs.
Room Temperature Direct Band-Gap Emission from an Unstrained Ge P-I-N LED on Si
Authors: Arguirov Tzanimir , Kittler Martin , Oehme Michael , Abrosimov Nikolay V. , Kasper Erich , Schulze Jörg
Published: August 2011

We present a novel Ge on Si based LED with unstrained i-Ge active region. The device operates at room temperature and emits photons with energy of 0.8 eV. It basically resembles a p-i-n structure formed on a sub-micrometer thin Ge layer. The Ge layer has been grown on Si substrate by utilizing thin virtual buffer, so it becomes stress free but with high threading dislocation density. We show that such forward biased diode generates strong emission, caused by direct band to band transition in Ge. Using an InSb based detector we were able to analyze the emission spectrum in a broad energy range. We show that at low and moderate currents, features belonging to the direct and the indirect band to band electronic transitions are present which are characteristic for Ge. Clearly dominating is the direct transition related peak. Due to the missing stress-related red shift this peak appears close to the desired communication wave length of 1.55 μm. The dependence of radiation intensity on the excitation current follows a power low with exponent of 1.7, indicating that the recombination rate of the competitive nonradiative processes is relatively low. At high excitation currents features appear in the low energetic part of the spectrum. All results presented here are discussed in view of the outcome from measurements on Ge high quality bulk material. The role of the dislocation in the Ge films is discussed.
Stress Relaxation Mechanism by Strain in the Si-SiO2 System and its Influence on the Interface Properties
Authors: Kropman Daniel , Mellikov Enn , Kärner Tiit , Laas Tõnu , Medvid Arthur , Onufrijevs Pavels , Dauksta Edvins
Published: August 2011

The results of the investigation of stresses relaxation by strain by means of EPR spectra, IR absorption spectra, SEM and samples deflection are presented. It has been shown that stresses relaxation mechanism depended on the oxidation conditions: temperature, cooling rate, oxide thickness. In the Si-SiO2-Si3N4system the stresses relaxation by the strain occur due to the opposite sign of the thermal expansion coefficient of Si-SiO2and Si3N4on Si. Laser irradiation allows to modify the system stresses.
New Results on the Bound Exciton Luminescence in Germanium
Authors: Allardt Matthias , Kolkovsky Vladimir , Kolodinski Sabine , Abrosimov Nikolay V. , Irmscher K. , Clauws Paul , Weber Jörg , Zuber Kai
Published: August 2011

Photoluminescence from excitons bound to shallow donors or acceptors was studied in Al-, As-, B-, Ga- and P-doped Ge. Excitons bound to Al and B acceptors were identified for the first time. The dissociation energy of the excitons satisfies Haynes rule and changes with a factor of 0.1 linearly with the ionization energy of the dopants.
Electron Mobility in Moderately Doped Si1-xGex
Authors: Emtsev Valentin V. , Oganesyan Gagik A. , Abrosimov Nikolay V. , Andreev Boris A.
Published: August 2011

Si1-xGex alloys with small atomic fraction of Ge, x≤ 0.05 are investigated. The Hall mobility of electrons in n-type materials was measured at cryogenic temperatures, T≤ 100 K. Taking into account the partial mobility due to charge carrier scattering by ionized centers and phonons it is possible to estimate the partial mobility associated with alloy scattering. It appears that this contribution to the electron mobility in n-Si1-xGex at low temperatures is important even at x≈0.01. The obtained results can be useful for understanding the nature of SiGe alloys and their transport properties.
Polycrystalline Silicon Layers with Enhanced Thermal Stability
Authors: Lysáček David , Šik Jan , Bábor Petr
Published: August 2011

We report on a new method of external gettering in silicon substrate for semiconductor applications. The proposed method is based on the deposition of a multilayer system formed by introducing a number of thin buried silicon oxide layers into the thick polycrystalline silicon layer deposited on the wafer backside. Oxide films of a few nanometer thicknesses significantly retard both the grain growth and subsequent loss of the gettering capability of the polycrystalline silicon layer during high temperature annealing. The mechanisms of the grain growth and the influence of the embedded oxide layers on the gettering function in the multilayer system are discussed. We used scanning electron microscopy and transmission electron microscopy for the characterization of the multilayer system, and intentional contamination for demonstration of the gettering properties.
Bistable Defects as the Cause for NBTI and RTN
Authors: Goes Wolfgang , Schanovsky Franz , Reisinger Hans , Kaczer Ben , Grasser Tibor
Published: August 2011

Over the last few decades convincing evidence has been collected demonstrating that the oxide reliability is most seriously affected by hole trapping into defects. Recently, valuable information has been delivered by a newly developed measurement technique called time-dependent defect spectroscopy (TDDS), which allows to analyze the behavior of single defects. It indicates the existence of additional metastable defect configurations which are necessary to explain various features seen in TDDS. In this study, it will be shown that these bistable defects may also be the origin of noise phenomena, such as temporary and anomalous random telegraph noise observed in MOSFETs.
Classification of Recombination-Active Defects in Multicrystalline Solar Cells Made from Upgraded Metallurgical Grade (UMG) Silicon
Authors: Lausch Dominik , Bakowskie Ronny , Lorenz Michael , Schweizer S. , Petter Kai , Hagendorf Christian
Published: August 2011

In this contribution a classification of recombination active defects in multicrystalline silicon solar cells made from electronic grade (eg) and upgraded metallurgical grade (umg) silicon feedstock is introduced. On a macroscopic scale the classification is performed by using forward and reversed biased electroluminescence imaging (EL / ReBEL) and imaging of sub-band defect luminescence (ELsub). The luminescence behavior due to structural defects already present in the wafer can be divided into two groups based on their recombination and prebreakdown behavior. As a first step towards a more detailed analysis of the cause for these differences, the classification was also performed on microscopic scale. For this ReBEL and ELsub was performed under an optical microscope (µReBEL/µELsub) and EL was replaced by Electron Beam Induced Current (EBIC). The defect types observed on a macroscopic scale could also be observed on a microscopic scale; however, a third defect type had to be introduced. Finally we propose a qualitative model for the different classified types of recombination active defect structures that can explain the observed recombination and prebreakdown behavior.
The effect of human resource practices on psychological contracts at an iron ore mining company in South Africa
Authors: Scheepers Caren B. , Shuping Johannes G.
Published: August 2011

Orientation: Human resource practices influence the psychological contract between employee and employer and, ultimately, organisational performance. Research purpose: The objective of this study was to examine the effect of human resource practices on the types of psychological contracts in an iron ore mining company in South Africa empirically. Motivation for the study: Although there have been a number of conceptual studies on the effect of human resource practices on psychological contracts, there has been no effort to synthesise the links between these contracts and various human resource practices systematically. This study endeavoured to provide quantitative evidence to verify or refute conceptual studies on this relationship. Its findings could inform human resource strategies and, ultimately, the prioritisation of human resource practices to improve the cost-effective allocation of resources.Research design, approach and method: The researchers administered two questionnaires. These were Rousseau’s Psychological Contract Inventory (2000) and the Human Resource Practices Scale of Geringer, Colette and Milliman (2002). The researchers conducted the study with 936 knowledge workers at an iron ore mining company in South Africa. They achieved a 32% response rate.Main findings: The findings showed that most participants have relational contracts with the organisation. Another 22% have balanced contracts, 8% have transitional contracts whilst only 1% have transactional contracts. The study suggests that there are relationships between these psychological contracts and specific human resource practices. The study found that training and development was the most important human resource practice for developing relational and balanced contracts. Employees thought that they contributed more than their employer did to the relationship. The researchers developed a model to illustrate the influence of the various human resource practices on psychological contracts.Practical/managerial implications: The influence of human resource practices on relational contracts could assist organisations to invest in human resource practices. During recessions, organisations tend to reduce expenditure on human resource practices, especially training and development. The findings of this study, about the relationship between training and development and relational contracts, highlight the negative effect that this trend could have on psychological contracts, individual and organisational behaviour and, ultimately, organisational performance.Contribution/value-add: Based on this empirical study, the researchers proposed a conceptual model to illustrate the relationship between different psychological contracts and specific human resource practices, like training and development, which had the strongest relationships with relational contracts.
Optimizing a beef production system using specialized sire and dam lines
Authors: Tang G. , Stewart-Smith J. , Plastow G. , Moore S. , Basarab J. , MacNeil M. , Wang Z.
Published: August 2011

Tang, G., Stewart-Smith, J., Plastow, G., Moore, S., Basarab, J., MacNeil, M. D. and Wang, Z. 2011. Optimizing a beef production system using specialized sire and dam lines. Can. J. Anim. Sci. 91: 353–361. Crossbreeding is an effective method for improving the efficiency of production in commercial cow-calf operations. It exploits available heterosis (hybrid vigour) and complementarity between different breeds or populations (lines). Before adopting a crossbreeding system, commercial cattle producers should evaluate available genetic resources and feasible crossbreeding systems, and choose one that is most beneficial for their own environment, resources, and management. This study compared profitability of alternative crossbreeding systems based on Beefbooster beef cattle breeding strains through computer simulation. Biological and economic data were collected from commercial customers of Beefbooster in Montana and western Canada, and breeding records from the database of Beefbooster, Inc. Three maternal strains (M1, M2 and M4) and two specialized paternal strains (M3 and TX), were evaluated with two simulated crossbreeding systems. System 1 uses a rotational cross between M1 and M4 with yearling crossbred heifers bred to M3 sires. System 2 is based on a three-strain rotation of M1, M2 and M4 with yearling crossbred heifers bred to M3 to facilitate ease of calving and crossbred cows bred to a classical terminal sire strain TX. Simulated base profit from system 2 was $29.57 greater ($215.21 vs. $185.64 yr−1 per cow) than from system 1.
Effects of an early lipopolysaccharide challenge on growth and small intestinal structure and function of broiler chickens
Authors: Hu Xiao , Guo Yu , Li Jian , Yan Gui , Bun Sideoun , Huang Bei
Published: August 2011

Hu, X. F., Guo, Y. M., Li, J. H., Yan, G. L., Bun, S. and Huang, B. Y. 2011. Effects of an early lipopolysaccharide challenge on growth and small intestinal structure and function of broiler chickens. Can. J. Anim. Sci. 91: 379–384. Two experiments were conducted to determine the effect of early exposure to lipopolysaccharide (LPS) on small intestinal structure and function of broiler chickens. Seven-day-old birds were randomly allotted to two equal treatments: an LPS-injected treatment in which the birds were injected intraperitoneally with LPS 500 µg kg−1 body weight (dissolved in 1 mL saline) on 8, 10, 12, 15, 17, and 19 d of age, i.e., on days 1, 3, and 5 d for 2 continuous weeks, and a control treatment (CTRL) in which the birds were similarly injected with 1 mL saline as a placebo. In exp. 1, food intake and weight gain were monitored over the 2 wk, the weight of the small bowel was determined at 14 and 21 d of age and duodenal and jejunal villus height and crypt depth, D-xylose uptake were also measured at 21 d. In exp. 2, additional measurements of the intestinal peristalsis ratio and the BrdU-labeling index and duodenal sodium-glucose co-transporter-1 (SGLT1) mRNA level were made at 21 d of age. The results showed that LPS challenge decreased feed intake, daily gain, duodenal and jejunal villus height and crypt depth, plasma D-xylose concentration and intestinal BrdUrd-labeling index, respectively (P<0.05) as well as small bowel weight at 14 and 21 d of age (P<0.05). Conversely, LPS injection increased SGLT1 mRNA level in the small intestine (P<0.05) and the small intestinal relative weight at 14 (P<0.05) and 21 d of age (P=0.063). Following LPS injection there were non-significant changes in feed conversion ratio and intestinal peristalsis ratio (P>0.05). In conclusion, early LPS challenge delayed the growth of intestine and impaired small intestinal structure and absorptive function.