bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Material of Small Radius Ball End Mill on Cutting Accuracy in Deep Precision Machining
Authors: Akamatsu Takeshi , Kitajima Koichi , Minamino S. , Kiriyama T.
Published: March 2009

Machining of complex shape and deep micro cavity in die and mold is mostly carried out by electrical discharge machining process. However, it may not be able to sufficiently meet delivery deadline minimization and cost reduction of die and mold. Therefore, precision machining method using small radius ball end mill capable of machining deep cavities in miniature die and mold is proposed as a substitute for electrical discharge machining. This report presents such a result supported by experiment in which it has been proved that long tool life of ball end mill can be
maintained by changing coating material and edge profile of small radius ball end mill experiencing form accuracy and get needed surface finish in workpiece. Therefore, for precision machining of die and mold as substitute for electrical discharge machining, it is proposed to perform deep precision machining using small radius ball end mill. This paper shows effect proved by experiment how cutting characteristics which occur by changing of coating material and edge profile of small radius ball end mill influence form accuracy and finishing surface of workpiece.
Performance of an Electrically Conductive CVD Diamond Electrode for EDM and FEM Analysis for a Very Low Wear
Authors: Suzuki Kiyoshi , Iwai Manabu , Sharma Anurag , Ninomiya Shinichi , Uematsu Tetsutaro , Sano Sadao
Published: March 2009

The performance of electrically conductive CVD (called EC-CVD) diamond thick film possessing a high thermal diffusivity has been examined as an electrode for fine electrical discharge machining (EDM). The results indicate a possibility of zero wear in EDM as compared to copper and copper-tungsten (Cu-W) electrodes. It is particularly significant at short pulse EDM conditions, where the EC-CVD diamond electrodes showed increased machining efficiency and a remarkably low wear. In EDM of tungsten carbide, a very low electrode wear ratio of 0.3% was realized with the EC-CVD diamond electrode. Zero wear EDM could be achieved even for sharp V-shapes with included angles of 15 and 30° with V-shaped EC-CVD diamond electrodes. Thermal FEM analysis to examine the relation between the thermal diffusivity and temperature distribution at short pulse duration indicated lowest temperature on EC-CVD diamond electrode surface.
Study on the Dimensional Precision of the Polymer SLS Prototype
Authors: Liu H.J. , Li Y.M. , Hao Yuan , Huang N.Y. , Shi Yu Sheng
Published: March 2009

Selective Laser Sintering (SLS) has many advantages such as fast building speed, wide range of materials, complicate shape of prototype and simple post-treatment. However, the shrinkage and mechanical stresses result in lost of the accuracy. This paper investigates the dimension precision of polymer SLS prototypes and proposes methods to control dimensions in suitable degree. The
influencing factors of dimensional precision in the file preparation of CAD model, manufacturing system of SLS prototype and sintering process are analyzed. It indicates that the sintering shrinkage in sintering process is the main reason of dimensional changes. To improve the dimensional precision, the measures are proposed to diminish the shrinkage: improving material of prototype, optimizing the
sintering process and compensating the lost of dimension. After analysis the experimental results, the rule of error changes is summarized by fitting equations and feedback to controlling software of SLS system to improve the dimensional precision effectively. The SLS prototype could be controlled in 100±0.20mm through compensation.
Arc Spray Forming of Stainless Steel Mould
Authors: Zhao Zhi Yu , Fang Jian Cheng , Wang H. , Li H.Y.
Published: March 2009

In order to improve the lifespan and performance of the forming mould with low
melting point, arc spray forming of stainless steel mould has been advanced. The technical process of spray mould has been investigated, and the correlations among the spray parameters, in-flight characteristics of molten particle and the forming quality have been analyzed in detail. Meantime, the influence of the preheating temperature of the spray mould and the spray angle on the morphology of the splashing particles has been also investigated. The research results indicate that the atomization pressure greatly influences the velocity and granularity of the in-flight particles. The working current greatly influences the particle temperature, and the spray distance influences the temperature and velocity to some extent. A compact spray layer, with a low porosity, little oxide content, and high microhardness, can be obtained by increasing the atomization pressure. The research has a great significance to optimize and control the forming quality of rapid tooling by arc spraying.
Wavelet Transform Domain Filter and Its Application in Incipient Fault Prognosis
Authors: Li Fu Cai , Chen Jin , Zhang Gui Cai , He Zheng Jia
Published: March 2009

Noise is the biggest obstacle that makes the incipient fault prognosis results uncorrected. According to the theories of correlation analysis and threshold de-noising by wavelets, wavelet transform domain filter (WTDF) is constructed. WTDF is an iterative process. By selecting the process parameters adaptively, WTDF can de-noise signal efficiently. More important, the faint component in the signal will become stronger. WTDF method is used to analyze the signals collected from a bearing that has incipient unbalance and misalignment faults. Results show that WTDF is effective for bearing incipient fault prognosis.
Damage Location in Beam and Plate Structures by Wavelet Analysis of Experimentally Determined Mode Shapes
Authors: Rucka Magdalena , Wilde Krzysztof
Published: March 2009

In this paper a method for estimating the damage location in beam and plate structures is presented. A plexiglas cantilever beam and a plexiglas plate with one fixed boundary condition are tested experimentally. The dynamic response of the structures is analyzed using one and twodimensional continuous wavelet transforms of the structural mode shapes. The location of the crack is indicated by a peak in the spatial variation of the transformed response. The proposed wavelet analysis can effectively identify the crack position without knowledge of either the structure characteristics or its mathematical model. The practical application of the technique for civil engineering structures requires only the response of the structure.
An Investigation on Vibration-Based Damage Detection in an Aircraft Wing Scaled Model
Authors: Trendafilova Irina
Published: March 2009

This work investigates the use of two different vibration-based methods for health monitoring of aircraft wings. A finite element model of a simplified wing is used to model and predict the vibration response of an aircraft wing in an intact condition and in the presence of different types and levels of damage. Two main types of damage are considered- cracks and distributed damage. This study first explores the sensitivity of the lower modal frequencies to different damage levels of the studied types. Then the employment of the frequency response functions subjected to principal components analysis is discussed. This is an early model-based study which is intended to establish if the considered procedures can be used as damage detection tools.
Intelligent Fault Diagnosis in Power Plant Using Empirical Mode Decomposition, Fuzzy Feature Extraction and Support Vector Machines
Authors: Hu Qiao , He Zheng Jia , Zi Yanyang , Zhang Zhou Suo , Lei Yaguo
Published: March 2009

In this paper, a novel intelligent fault diagnosis method based on empirical mode
decomposition (EMD), fuzzy feature extraction and support vector machines (SVM) is proposed. The method consists of two stages. In the first stage, intrinsic mode components are obtained with EMD from original signals and converted into fuzzy feature vectors, and then the mechanical fault can be detected. In the second stage, these extracted fuzzy feature vectors are input into the multi-classification SVM to identify the different abnormal cases. The proposed method is applied to the classification of a turbo-generator set under three different operating conditions. Testing results show that the classification accuracy of the proposed model is greatly improved compared with the multi-classification SVM without feature extraction and the multi-classification SVM with extracting the fuzzy feature from wavelet packets, and the faults of steam turbo-generator set can be correctly and rapidly diagnosed using this model.
Wave Propagation Based Multi-Crack Identification in Beam Structures through Anti-Resonances Information
Authors: Wang Dan Sheng , Zhu Hong Ping
Published: March 2009

Cracks bring a serious threat to safety of structures. Most of the failures and fractures of engineering structures are due to initial cracks or fatigue cracks of materials. So it is very important to analyze the vibration characteristics and to identify the damage of cracked structures. A method for multi-crack identification based on wave propagation is proposed in this paper, which makes use of the driving-point mechanical impedance characteristics of the cracked beams stimulated by harmonic force. The proposed identification method is used to characterize the local discontinuity due to cracks, and a simplified rotational spring model is introduced to model cracks. Subsequently, the proposed method is verified by a numerical example of a simply supported steel beam with three cracks. The effect of crack depth on driving-point impedance is investigated. Combined with the first anti-resonances information, the proposed method can identify the presence of cracks, localize the multiple cracks, and qualitatively identify the extent of the crack damages.
Damage Detection on Typical Aeronautical Structures
Authors: Rodríguez Rosamaria , Yarza A. , López-Díez J. , Cuerno-Rejado C. , Güemes A.
Published: March 2009

The paper pursues the exploration of the feasibility and reliability of current damage detection technologies, evaluating their detection capabilities, environmental factors effects, false alarms rate, adaptability to complex geometries, etc. The method to be used is based on finite element modal updating. Three aspects, as outlined below, are covered: testing samples will be aluminium sheets (0.6m x 0.4m x 1.6mm) strengthened with riveted L-shaped stiffeners. Data will be presented from the undamaged specimens. Secondly, the testing of the samples with damage simulated at different places by temporary removal of specific rivets, thus affecting the overall structural characteristics of the structure. The models used for damage identification methods will be fine tuned to properly detect the simulated damages. Finally, using this information, the paper resumes the capabilities of the method to detect and locate the simulated damage.
Frequency-Demodulated Analysis Based on Cyclostationarity for Local Fault Detection in Gears
Authors: He Jun , Chen Jin , Bi Guo , Zhou Fuchang
Published: March 2009

The demodulation analysis has been extensively used for gear diagnosis. However these techniques mainly deal with the amplitude-modulated signal instead of the frequency-modulated signal. Due to the symmetrical phase relationship of the sidebands, the amplitude-demodulated methods are not suitable for the frequency-modulated signal. This paper introduces the theory of cyclostationary processes as a powerful frequency-demodulation tool for the diagnosis of gears. The Cyclic Autocorrelation Function (CAF) is an important second-order cyclic statistics and acts as an efficient parameter to the frequency-demodulated analysis. In this paper, the CAF of frequency-modulated signal is deduced carefully. Through the discussion of frequency feature of the CAF slice at different cyclic frequency, two useful conclusions have been arrived about the frequency-demodulation. Firstly, the CAF slice at even multiples of the modulator-frequency can demodulate the frequency-modulated signal directly. Secondly, the amplitude-demodulated methods are suitable for the CAF slice of frequency-modulated signal at some special cyclic frequencies, which are equal to odd multiples of the modulator-frequency or close to the double carrier-frequency. These features of the CAF slice mentioned above overcome the invalidation of amplitude-demodulated methods for the frequency-modulated signal and increase it’s application range in engineering. Application in simulated and experimental data from a gear rig verifies the effectiveness of the frequency-demodulated method based on cyclostationarity.
Design and Simulation of a DETF for Use in a Resonant Gyroscope
Authors: Zhu Yi Lun , Wang S.R. , Qiu A.P.
Published: March 2009

The principle of operation of double-ended resonant tuning forks (DETF) is described in this paper. A new kind of DETF used in the resonant gyroscope is proposed. Considering the feasibility of fabrication, the dimensions are optimized. The variation of the natural frequency against the force applied to one end of the DETF is discussed. The relation between the driving modal frequency of resonant gyroscope and the driving modal frequency of DETF is analyzed.
A Scanning Multi-Probe Straightness Measurement System for Alignment of Linear Collider Accelerator
Authors: Gao Wei , Yokoyama J. , Kiyono S. , Hitomi N.
Published: March 2009

This paper describes a scanning multi-probe measurement system for local alignment of linac components. The system consists of two probe-units, each having three displacement probes. The two probe-units, which are placed on the two sides of the cylindrical linac components, are moved by a scanning stage with a scanning range of 5 m to simultaneously scan the two opposed straightness profiles of the linac cylinders. A differential output calculated from the probe outputs in each probe-unit cancels the influence of error motions of the scanning stage, and a double ntegration of the differential output gives the straightness profile. The difference between the unknown zero-values of the probes in each probe-unit of zero-difference, which introduces a parabolic error term in the profile evaluation result, is calculated and compensated for by a zero-adjustment method so that accurate straightness profiles of the linac cylinders can be obtained. The effectiveness of the measuring system is confirmed by experimental results.
A Circular Profile Measurement Method Using Software Techniques
Authors: Okuyama Eiki , Mitsui Kimiyuki
Published: March 2009

In industry, disk type products with a highly accurate surface such as silicon wafer and hard disk, are important elements. To measure these surfaces, an interferometer is used. However, this method generally needs a highly accurate reference surface. Another method to obtain the disk surface profile is by a scanning displacement sensor. However, the output of this sensor is influenced by the parasitic motions of the scanning along the reference guide. This article presents novel measurement procedures, a reversal method, an improved reversal method and a multi-prove method, to measure the circular profile on a disk without any references but with high accuracy.
Theoretical Analysis and Basic Experiments for the 3D Displacement Measurement Using Ring-Shaped Laser Beam
Authors: Usuki S. , Enami Kazuyuki , Hiraki M. , Takahashi S. , Takamasu Kiyoshi
Published: March 2009

For flexible 3D positioning of a complex 3D mechanism, it is needed to measure 3D displacement of the end-effecter of the mechanism in high precision and by non-contact method. It was common to use plural sensors or scales together to measure the 3D displacement. However, it is difficult to calibrate the sensitivities of the plural sensors or scales. A novel 3D displacement measurement is proposed using an optical system in which lens focuses are collected at the center of the sphere, which has been used for the radius measurement of the sphere. Instead of facing in the XY direction that has high sensitivity, new ideas are necessary for the measurement in the Z direction of the optics where focuses are collected at the center of the sphere. The displacement in the XY direction and the one in the Z direction can be measured at the same time by using a ring-shaped laser beam instead of a simple ray.
A Structured-Light-Based On-Line 3D Measurement System and Software Development
Authors: Yu X.Y. , Zhang F.B. , Yuan H.J. , Lang Z.G.
Published: March 2009

The objective of this work is to develop a 3D measuring system for on-line 3D measurement in industry locale. Our system is based on the depth image using a structured-light method. A generator emitting a single stripe light and a camera are used to establish a 3D vision measurement system which is also called as a subsystem. But it only can obtain the depth image of a part at the measured object section. Our system is made up of four subsystems placed symmetrically in space. The depth images obtained by the subsystems are joined to form the depth image of a full section. If the object is uniformly shafted along a fixed beeline direction, the depth image of the full object surface is achieved. The indefiniteness in the image combination criterion can be removed when using the depth image. This paper introduces the system principle and the mathematical model. The algorithm is proposed with system parameters. A prototype is developed. The system has the range of 100mm in height x 100mm in width. The length is not limited. The measuring error is less than 0.5mm in height and width and less than 0.01mm in length. The characteristics make the system suitable for on-line 3D shape measurement and non-contact measurement with high speed.
A Laser Sensor Technique for Measuring 3D Surfaces Based on the Polarized Heterodyne Astigmatic Principle
Authors: Qiu L.R. , Ding X.M.
Published: March 2009

A laser measurement technique based on polarized heterodyne astigmatic principle is proposed for high precision three-dimensional (3D) profile measurement. In the presented system, the defocus astigmatic signal coming from the polarized reflection of the detected 3D surface is used to determine the position of the surface. The work of tracing, scanning and processing of the detected 3D surface is performed by combining the system with an ultra precision laser coordinate measuring machine (CMM). Compared with the current heterodyne astigmatic measuring technique, a polarization incidence and Glan-Thompson prism (GP) is used in the novel polarized heterodyne astigmatic measuring method. The anti-interference ability of the optical sensing system is significantly improved. The undesired influence on the measurement results, caused by fluctuation of surrounding brightness, by the intensity disturbance of the laser source, and by the multi-reflection among optical elements, is effectively restrained. Experimental results show that the stability of the optical sensing system is better than 2%. The resolution of the system is better
than 0.005µm.
Detection of Vortex Frequency in Gas Flow with Ultrasound
Authors: Hans Volker , Filips C.
Published: March 2009

The coincidence of vortices generated by a bluff body in a gaseous flow (Karman vortex street) with an ultrasonic beam crossing these vortices raises a lot of questions concerning physics and signal processing. The ultrasonic signal will be complex modulated. The spectrum of the resulted signal shows the carrier frequency of ultrasound and two narrow sidebands with the information about the modulation. For further signal processing the carrier frequency must be filtered. The carrier frequency can be shifted to zero by digital processing and undersampling the signal by an integer multiple. Then the sideband with its low frequency range can be analysed. The real and imaginary parts of the signal can be determined by sampling the signal shifted by 90 degrees (Hilbert transform). Even the 90 degree shifted angle can be measured by undersampling. The sensitivity of the vortex meter depends on the bluff body size. A simple relation between the bluff body dimension and the sensitivity, the vortex frequency, respectively, is shown.
Performance Characterization of Pressure Sensors Using an Improved Pressure Square Wave Generator
Authors: Tsung Tsing Tshih , Han Lee Long , Chen Liang Chia , Chang Ho
Published: March 2009

The purpose of this paper is to analyze and compare the dynamic characteristics of various structure pressure sensors using the Improved Pressure Square Wave Generator (IPSWG). The developed IPSWG is a signal generator that creates pressure square waves as an excitation source. The dynamic characteristics of pressure sensor in hydraulic systems can be measured and evaluated effectively due to the high excitation energy. The method is also useful for dynamic testing and characterization for a high frequency range, which cannot be performed by the traditional methods, such as the hammer kit excitation, sweeping frequency pressure wave, and random frequency wave. Result shows that piezoelectric sensors (quartz) have a largest gain margin and overshoot. The strain gauge sensor has a smaller gain margin and overshoot. The piezoelectric sensor is more suitable for measuring dynamic pressure.
Design of an Intelligent Multi-Gyro Measurement Device
Authors: Wang J.P. , Zhou W. , Tian W.F. , Jin Z.H.
Published: March 2009

This paper describes the design of an intelligent multi-gyro measurement device to measure and monitor an inertial unit composed of three dynamically tuned gyros (DTGs). A 16-bit microprogrammed control unit is programmed to fulfill the functions of signal processing, logic control and serial communication with a master computer. An FPGA, designed by using Verilog Hardware Description Language, is used to realize high speed 16-bit reversible counters for output pulses of the DTG digital dynamic balance circuits. The count values represent the angular motion of the inertial unit. A stepping electric bridge is employed to measure the resistance of thermal resistors within the gyros in a wide temperature environment. The resistance represents the working temperature of the gyros. An effective calibration method for the bridge is developed to eliminate the resistance measurement error. A test system is established to examine whether the device meets the user requirements. Results of the tests show that the device has a good performance. A trial use has proved that the device is stable and reliable and that it satisfies the demand of the user.
An X-Y Stage with a Plane Cross Grating Metrology System
Authors: Wang Xuang Ze , Gao Y. , Guo Jun , Xie T.
Published: March 2009

This paper describes an X-Y stage with a plane cross grating for position feedback. The stage has a current servo motor and a piezoelectric actuator to realize coarse and fine positioning throughout the 50mm x 50mm range of travel. The objective table contacts tightly on a planar wafer to enhance the motion flatness. The horizontal positioning noise is less than 20nm. The stage has a positioning accuracy of 3µm. If a high quality grating and guide is used, it should be useful for 3D surface measurement and ultra-precision machining. The operating principle and the characteristics of the plane cross grating are presented. The internal structure is explained. The comparison result for the stage with a laser interference calibration is presented. The theoretical precision and error sources of the system including grating grid, guide and grating installation error are analyzed. Experiments on factors such as system noise, guide error and motion interference are presented and the results are analyzed.
Surface Reconstruction Based on Laser Scan Data
Authors: Luo Yi Ping , Jiang Zhuang De , Li B. , Wang Y.G.
Published: March 2009

The problem of freeform surface reconstruction starting from a cloud of points measured by a laser scanning system is examined. The objective is to fully integrate reverse engineering and laser scanning for rapid product development. The measuring principle and the configuration of the system are investigated. Based on non-uniform rational B-spline (NURBS) curve and surface, the freeform curve, the surface reconstruction method, the step and parameterization algorithms are introduced. The interfaces between initial graphic exchange specification (IGES) and stereo lithography interface specification (STL) with CAD and rapid prototyping manufacturing (RPM) system are discussed. The system is developed based on an open graphics library (OPEN GL) software environment. A practical case is presented to illustrate the effectiveness of the approach.
Sub-Pixel Edge Detection for Precision Measurement Based on Canny Criteria
Authors: Xie S.H. , Liao Qiu , Qin S.R.
Published: March 2009

A new nonlinear intensity interpolation algorithm is presented to realize sub-pixel edge detection. The interpolation algorithm based on the Canny criteria makes full use of grads information attained by Canny edge detection to perform special interpolation in the grads direction. When the resolution is enhanced, the interpolated image by the new interpolation scheme can efficiently preserve high frequency component in the original image. The edge detection of interpolated image permits high precision localization. The new interpolation algorithm is more effective in reserving the grads information of the step edge of the initial image than the usual linear interpolations. It requires simpler computation than the present non-linear interpolations.
Online Calibration for a Stereo Vision Measurement System
Authors: Yu Z.J. , Ma S.Y. , Che R.S. , Wang Q.Z. , Tian W. , Li Z.H. , Li J.Z.
Published: March 2009

A new method for calibrating stereo vision measurement system is presented. By moving a rigid optical reference bar in a pattern in and around the measurement volume, the relative orientation and position of the two cameras can be determined by using the epipolar constraint, the linear normalization eight-point algorithm and the M-estimator method. The scale factor of the translation between the two cameras can be calculated by the distances between the marks on the reference bar. With automatically controlled infrared LED marks, the imaging feature points have a uniform intensity profile and a high contrast with background. The calibration accuracy can be improved. The simulation and experiments have shown that the calibration accuracy can be comparable with the complex off-line calibration.
Micro-Force Calibration with an All-Coil Magnetic Levitation
Authors: Hsu S.W. , Chen T.L.
Published: March 2009

A prototype all-coil electromagnetic force balance has been designed and built. This measurement system compares the mechanical force to an SI realization of electromagnetic force, which is driven from interaction of currents in radial coil set and levitation coil. The preliminary measurement results demonstrate that the magnetic field distribution and magnetic force output are consistent with the results by simulation.
Synthesis and Evaluation of Electrochemical Properties of Mesoporous Anatase Titania
Authors: Okada Tomomi , Miyayama Masaru
Published: March 2009

Lithium intercalation properties were investigated for mesoporous titania, prepared by hydrolysis of titanium tetrabutoxide followed by calcining at various temperatures. X-ray diffraction analysis showed that synthesized titania were anatase phase. The B.E.T. surface area of mesoporous titania decreased with increasing calcining temperature, but that of mesoporous titania calcined at 450°C was over 50 m2/g. Lithium intercalation capacities of mesoporous anatase increased with increasing calcining temperature up to 450°C. Mesoporous anatase titania calcined at 450°C showed a capacity of 118 mAh/g at a current density of 1 A/g. The lithium intercalation properties depended on crystallinity, remaining water content and mesopore size.
Effect of Growth Conditions on the Cathodoluminescence of β-Ga2O3 Crystals Grown by Electric Current Heating Method
Authors: Suzuki Kenichi , Kuroki Yuichiro , Okamoto Tomoichiro , Takata Masasuke
Published: March 2009

Beta gallium oxide (β-Ga2O3) crystals were grown on β-Ga2O3 ceramics heated by electric current under vacuum at various ambient temperatures. From cathodoluminescence at room temperature, emission peaks at 2.9 and 3.5 eV were clearly observed. With increasing ambient temperature, the relative intensity of ultraviolet emission (3.5 eV) to blue emission (2.9 eV) showed a peak at 400oC. These results suggest that the ambient temperature during the electric current heating of β-Ga2O3 ceramics in vacuum is one of the most effective factors for the ultraviolet emissive β-Ga2O3 crystal.
Microfabrication of Thermoelectric Hydrogen Sensor Using KOH Solution Etching
Authors: Tajima Kazuki , Choi Yeong Soo , Shin Woosuck , Izu Noriya , Matsubara Ichiro , Murayama Norimitsu
Published: March 2009

Micromachined sensors are a new generation of sensor technology combining existing integrated circuit fabrication technology with novel deposition and etching processing. In the viewpoint of low-power operation, high sensitivity and fast response speed of thermoelectric hydrogen sensor (THS), we prepared the micromachined thermoelectric hydrogen sensor (micro-THS) with the combination of the thermoelectric effect of SiGe thin film and the Pt-catalyzed exothermic reaction of hydrogen oxidation. The power consumption of the micro-THS was greatly reduced to be 50 mW for 100 °C operating, by the Pt-micro-heater on single membrane. The micro-THS with 40 wt.% Pt/alumina catalyst showed voltage signal of 10 mV for 1 % H2 in air.
Effect of Mn and Co Addition on Electrical Degradation of ZnO Varistors
Authors: Yoshino Hiroyuki , Takada Masayuki , Morioka Jyunya , Yoshikado Shinzo
Published: March 2009

The effects of Mn and Co addition on the electrical degradation of ZnO varistors were investigated on the basis of voltage-current (V-I) characteristics, X-ray diffraction (XRD), capacitance-voltage (C-V) characteristics, and isothermal capacitance transient spectroscopy (ICTS). The optimum Co content for preventing electrical degradation was determined to be approximately 0.5mol% in Bi-Mn(0.5mol%)-Co(0~1.0mol%)-added ZnO varistors. Correlations between the improvement of electrical degradation and the structural changes of additives were investigated by XRD. It is suggested that the crystal structure of a-Bi2O3 at the grain boundary changes to a different structure, such as d-Bi2O3 or Bi7.65Zn0.35O11.38 with a fluorite-type structure, at the optimum Co content. It is speculated that the structural change of Bi2O3 at the grain boundary contributes to the improvement of electrical degradation characteristics. Three trap levels were detected in all Bi-Mn-Co-added samples by ICTS. These trap levels showed a local maximum at the optimum Co content.
Giant Polarization Properties of Ba-Based Bismuth Layer-Structured Ferroelectrics
Authors: Kobayashi Tomo , Noguchi Yuji , Miyayama Masaru
Published: March 2009

Intergrowth-structured Bi4Ti3O12-BaBi4Ti4O15 (BiT-BBTi) single crystals were grown by a self-flux method, and the crystal structure and polarization properties were investigated. Transmission electron microscope observations and X-ray diffraction analysis presented direct evidence of the intergrowth structure composed of the alternate stacking of BiT and BBTi layers. The BiT-BBTi crystals showed a giant spontaneous polarization (Ps) along the a axis of 52 μC/cm2, which was larger than those of the crystals of BiT (46 μC/cm2) and BBTi (16 μC/cm2). The large Ps of the BiT-BBTi crystals is suggested to originate from the ferroelectric displacements of the Bi of Bi2O2 layers as well as from the Bi substitution for Ba induced by compositional deviation. It was found that the polarization properties of the BiT-BBTi crystals depend strongly on the composition.
Dielectric and Piezoelectric Properties of Ba(Ti,Zr)O3 Thin Films Consisted of Nano-Crystals
Authors: Tanaka Kiyotaka , Suzuki Kazuyuki , Kimura Tatsuo , Nishizawa Kaori , Miki Takeshi , Kato Kazumi
Published: March 2009

Lead-free Ba(Ti1-xZrx)O3 (BTZ) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by the chemical solution deposition (CSD) process. The microstructure of the BTZ (x = 0.00 to 0.20) thin films was improved by additional sintering process, and their crystallite sizes were increased in each composition. The dielectric constant er and piezoelectric constant d33 of the BTZ thin films depended on the crystallite size. We give a guide for further investigation to improve the characteristics of BTZ thin films.
Growth and Characterization of AlBN Polycrystalline Thin Film by Radio-Frequency Plasma-Assisted Molecular Beam Epitaxy
Authors: Yamashita Masashi , Ishikawa Yukari , Ohsato Hitoshi , Shibata Noriyoshi
Published: March 2009

An AlBN thin film with a boron content (B/(Al+B)) of 0.1 or 0.3 was obtained by radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE) using EB-guns as group-III element sources and an RF radical source for nitrogen supply. We compared the characteristics of the film with those of AlN and BN films. By reflective high-energy electron diffraction (RHEED), we observed ring patterns in the AlBN film. The X-ray photoelectron spectroscopy (XPS) N1s peak of the AlBN film was observed at a binding energy between the peaks of AlN and BN. There was no evidence for phase separation in the film.
Study on Abilities of Mineral Admixtures and Geopolymer to Restrain ASR
Authors: Li Ke Liang , Huang Guo Hong , Jiang Lin Hua , Cai Yue Bo , Chen Jian , Ding Jian Tong
Published: March 2009

This paper deals with the effect of mineral admixtures and Geopolymer on preventing
excessive expansion due to alkali-silica reaction (ASR). The test method used was ASTM C 441-97. Expansions of mortar-bars were measured at 14, 56, 90 days. The results prove that mineral admixtures can effectively restrain ASR. When three kinds of mineral admixtures, silica fume, fly ash, and ground granulated blast-furnace slag (GGBS), were used together, they bring about a compound effect which is more effective to restrain ASR. Mortar expansion can be reduced 81.9 %
by this compound effect. Chemical analysis of the pore solution shows that mineral admixtures reduced concentrations of hydroxyl, potassium and sodium ion, so that damages from ASR decreases. Geopolymer, an amorphous inorganic material, was prepared with metakaolin and other mineral admixtures in the condition of high pH. Alkalis fixed in the framework of Geopolymer, there are no enough alkalis to react with active aggregates. Geopolymer does not generate any dangerous alkali-silica reaction even with alkali contents as high as 12.1 %.
A Development of the Research on High Performance Concrete Incorporated with High Volume Fly Ash
Authors: Xing Feng , Guo Xiang Yong , Leng Fa Guang , Zhang Ren Yu
Published: March 2009

In this paper, the main characteristic of definition, property, requirement of raw material, mix proportion design and performance improvement of high volume fly ash concrete (for short HVFAC) are summarized. The applications of HVFAC in dam, highway, building and port are introduced. The research results have shown that HVFAC have outstanding properties of physical mechanics, but some problems need to be further studied. It is believed that an operable strict corresponding technical criterion would be set down as soon as possible for engineering practice.
Quality Improvement of Recycled Aggregate Concrete
Authors: Tam Vivian W.Y. , Gao X.F. , Tam C.M.
Published: March 2009

The developments of recycled aggregate concrete pressing hard in construction activities; however, the limitations on their applications had never being ended. The focus of this paper is: i) investigating the waste management strategy in construction; ii) proposing the two-stage mixing approach (TSMA) to improve the quality of RAC; and iii) experimenting the TSMA and assessing the benefits possibly gained. It proposes a new approach in mixing concrete, namely, the two-stage mixing method, to improve compressive strength of RAC and lower its strength variability. The replacement ratio from zero to thirty is under experiment on their compressive strength. Based upon the experimental results, improvements of 31 % in strength at 28 days with 30 % RA substitute was achieved. The effect can be attributably to the porous nature of the RA and the pre-mix process which can make some pores filled up resulting in a denser concrete and thus leading to higher strength when compared with the traditional mixing approach. Therefore, two-stage mixing approach can open up a wider application of recycled aggregate concrete.
A Study on Supercritical Water Technology for Recycling of Building Materials
Authors: Yamamoto Keiki , Yuasa Noboru , Matsui Isamu , Hiaki Toshihiko , Tanaka Satoshi
Published: March 2009

Supercritical water (SCW) has both the solvent power approximate to liquids and the transport properties common to gases. It is therefore expected as an excellent solvent for industrial waste treatment. In this study, various building materials were treated with SCW, and their morphological changes after treatment were observed. The effects of SCW treatment on the pore structure and compressive strength of cement concrete and mortar were also investigated. In the range of this study, after SCW treatment, inorganic materials and organic materials can be recovered as solids and liquids, respectively. Under sub-critical and super-critical temperature and
pressure conditions, compressive strength of mortar decreases, while the effective pore volume increases.
Research and Applications of High-Anticorrosivity Concrete
Authors: Chen Cui Hong , Wang Yuan , Li Jing Huan , Jin Heng Gang
Published: March 2009

To improve the anticorrosivity of concrete, an analysis was made to the corrosivity/anticorrosivity mechanism of concrete followed by some relevant technical measures proposed to take. In the experiments, anticorrosive agent was used to prepare the high-anticorrosivity concrete with different proportioning. Both the experimental and application results showed that the concrete we developed had high physical/mechanical properties and durability especially the high anticorrosivity feature.
Proper Characterisation of Pore Size Distribution in Cementitious Materials
Authors: Hu J. , Stroeven Piet
Published: March 2009

In this paper, a mathematic morphology measurement with the name of opening operation was applied to section images for the assessment of pore size distribution in cement pastes. This method is compared with other methods for characterising pore size distribution, including the experimental technique of mercury intrusion porosimetry, the conventional image analysis by area histogram and a direct approach by a simulation model. The comparison study reveals that the so-called opening distribution technique yields realistic structural information of pore size distribution in cement pastes. The proper characterisation of pore size distribution is of significant importance to permeability prediction of cementitious materials and thereby to durability studies of the materials.
Analysis of a Sudden Failure of RC Roof Slabs in a Steel Mill
Authors: Hao Ting Yu , Hui Yun-Ling
Published: March 2009

Two Reinforcement Concrete (RC) roof slabs, with a size of 1.5 m×6 m, suddenly
dropped from the roof after 32 years service in a steel rolling workshop of a steel mill. By in-situ inspection and lab investigation, it was found that the failure of the roof slabs were due to the severe corrosion of the prestressed steel bar, which was induced by concrete degradation connected closely with the service environments of the slabs.
Research on Shear Resistant Capacity and Reliability of Multi-Ribbed Composite Wall in High-Rise Building
Authors: Jia Ying Jie , Yuan Quan , Yao Qian Feng
Published: March 2009

As a new structural system, MRSS (multi-ribbed slab structure) has some applications in multistory building. But theoretical investigation and application study on multi-ribbed composite wall in high-rise building should be developed with various factors composing shear resistant capacity of wall under complicated loads. By means of model test and numerical simulation with FEM (finite element method), shear resistant expression of slab in tall building is set up and reliability index of a representative wall under small earthquake is figured out. Sensitivity of each factor affecting shear strength is evaluated. These works disclose the wall’s load bearing mechanism and make the structure application more feasible and assure the new system safety in practice.
Study on Long Term Performance of Concrete of Slag-Alkali Higher Calcium Fly Ash
Authors: Tang Ming , Li Xiao
Published: March 2009

The slag-alkali is used to activate the activity of higher calsium fly ash. By the designs of the mixture ratio and the quadratic regression orthogonal design, the best combination is sought out. Several mixture factors which affect the rule of the concrete material properties and long term performance are researched. The mathematic models which are set up by the mixture ratio design with the quadralic regression orthogonal design can be effective. The precision is high. The strength
of the concrete of slag-alkali fly ash was still increasing after 8 year. The dispersion degree of those specimens is small. The SEM photo of cracked specimen and early concrete specimen shows the surface of fly ash in 7 days concrete is slick and that in 8 years old specimen has been enwrapped tightly by much hydrate plant.
Mechanism of the High Efficiency Grinding Fluid Used for Ceramics
Authors: Tian Xin Li , Wu Z.Y. , Yu Ai Bing
Published: March 2009

It is an effective method to enhance the engineering ceramic grinding efficiency using the organic grinding fluid added with the long chain alcohol. In the cutting-grinding experiment, the ceramic grinding efficiency was 2.4 times higher than the common grinding fluids. The microstructural analysis and the hardness testing performed for the liquid-solid interface using the Raman Spectrum technology and the nano impression technology found that there were abnormal peaks in the Raman Spectrum of the liquid-solid interface between the ceramics and the organic grinding fluid and the presence of abnormal peaks was familiar with the changing rules of surface hardness. The effect might change the grinding mode of the diamond grain micro-blade in the grinding process, thus to affect the grinding efficiency and the machining quality. It is a research direction to be further discussed.
The Formation and Control of Surface Cracks in the Cemented Carbide Materials in the Process of Grinding
Authors: Dong G.Q. , Wang Gui Cheng , Pei Hong Jie , Ma Li Jie
Published: March 2009

As the common materials of making cutting tool, the cemented carbide has been widelyused in all kinds of mechanical machining. Based on the manufacturing craft of the brazing welded cemented carbide cutting tools, according to the theory of engineering mechanics and fracture mechanics, the main factors are analyzed and studied which influence surface cracks of cutting tool from prefabricated stress σc, brazing stress σq, removable stress σw at heat preservation and extra
stress σf several aspects in this paper. Then the author founded the math-mechanics model of forming the surface cracks and deduced the critical condition generated surface cracks in brazing welded cemented carbide cutting tools and puts forward several kinds of technology, crafts and methods restraining or minishing surface cracks of the cemented carbide cutting tools.
Study on Chemical Mechanical Polishing Mechanism of LiTaO3 Wafer
Authors: Wei Xin , Yuan Hui , Du H.W. , Xiong Wei , Huang Rui Wei
Published: March 2009

In this paper, the scratching processes by a diamond indentor under the loads linearly increased from zero were studied to assess the mechanical behavior of LiTaO3 crystal wafer. Material removal mechanism of LiTaO3 crystal by mechanical loads was analyzed based on the measured acoustic signals in the scratching processes and the observation on the scratched surfaces of LiTaO3 wafers. The chemical mechanical polishing (CMP) processes of LiTaO3 wafers were analyzed in detail according to the observation and measurement of the polished surfaces of LiTaO3 wafers with SEM and XRD. The research results show that there exist four regimes along the scratched groove with the increasing of down force in a scratching process of LiTaO3 crystal wafer, and the critical load for each regime is affected by the loading speed and final load, etc. When H2O2
and KOH are added into the polishing slurry, the material of LiTaO3 wafer is removed by chemical reaction and mechanical action sequentially in the CMP processes, and the material removal rate increases while the surface roughness is improved.
Study on Ultra-Precise Machining of CLBO Crystal
Authors: Lv Xun , Yuan Ju Long , Dai Yong , Zheng Jia Jin , Zhou Zhao Zhong , Zhao Ping
Published: March 2009

Cesium Lithium Borate (CsLiB6O10 or CLBO) is the most effective non-linear crystal which generates ultraviolet harmonics of the Nd:YAG fundamental laser wavelength. In order to enhance the damage threshold, low CLBO surface roughness, by ultra-precision machining, is needed. Because the CLBO crystal has easy hydroscopic reaction and micro scratches in machining, ultra-precise machining of the CLBO crystal is a difficult technical problem. In this paper, the new lapping slurry and polishing slurry are introduced. And the deliquescence
degree of CLBO is fallen to lowest. A new working technology is also adopted. After rough polishing, the concentration of ultra-precision polishing slurry is increased properly. So does the ultra-precision polishing speed, and the wiping speed is faster than the deliquescence speed. The CLBO crystal surface roughness can achieve 1nm and keep the surface quality well.
Research on Tool Radius Compensation for 4-Axis Gang Control Grinding of Rolling Cutter Curve-Edge
Authors: Ruan Zhen , Hu De Jin
Published: March 2009

Rolling cutter curve-edge is a complex spatial curve. This paper states the present method of tool radius compensation for grinding it by 4-axis gang control grinding center, analyzes the existence of processing error due to this method, and proves the error can not be neglected. To avoid the error, a new method of tool radius compensation based on vector decoupling is raised. From a comparative experiment, it shows that the new method can promote processing precision and enlarge work-life of rolling cutter evidently.
EDM Dressing for Metal-Bond Super Hard Arc-Forming Wheel
Authors: Zhang Fei Hu , Kang Gui Wen , Yang Yong Shan , Shi Xing Kuan , Luo S.B.
Published: March 2009

In the process of ultra-precision grinding, workpiece can be ground with the arc area of the superfine and super hard arc-forming wheel. It is of great significance to study the precision dressing technology for super hard arc-forming wheels. EDM (Electron Discharge Machining) dressing can be the ideal dressing method for metal-bond super hard arc-forming wheel. Dressing device with pendulant electrode was designed. Polarity effects and the influences of different electrical
parameters on wheel dressing efficiency and accuracy were studied in the experiments. The forming results showed that EDM dressing can satisfy the dressing requirement of arc-forming wheel.
An Experimental Study on Creep Deformation of PBX with Laser Moiré Interferometry Method
Authors: Xie Hui Min , Shi Hang , Chen Peng Wan , Huang Feng Lei , Fang Dai Ning
Published: March 2009

In this paper, the creep deformation of PBX was measured using the moiré interferometry. The experimental results show a different creep process compared with pure high polymer and this phenomenon is preliminary analyzed from damage mechanics.