bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Measurement Accuracy Using Image Super-Resolution
Authors: Ling D.S.H. , Hsu H.Y. , Lin G.C.I. , Lee S.H.
Published: March 2009

A super resolution measurement technique is proposed to improve the accuracy of the automated stereovision measurement systems. Image super resolution is useful to reconstruct a visually enhanced high resolution image from a set of low resolution images. Due to the ill conditioning problem of the super resolution model, a-priori information is augmented into the model. We examined different a-priori and concluded that the Solution norm is the most suitable apriori to be used with the optimization technique described. Experiment also showed that the super resolution technique could perform measurement on small images, which are not possible without the technique. An increase in measurement accuracy from 99.73% to 99.91% is obtained.
An Application of the AGC Technology for Sensor Signal Processing
Authors: Liu Xiao Kang , Peng Dong Lin , Zhang Xing Hong , Cheng X.H.
Published: March 2009

Machining precision deficiency and installing error are very common problems for many sensors, which may result in unstable amplitude i the signal detected by the probe and further cause measurement errors of the sensors. The concept of using electronic technology to offset machinery precision deficiency is utilized. A new method of electronic rectifying is proposed. The automatic gain control (AGC) technology used in the field of wireless communication is applied for sensor signal processing. An AGC circuit consisting of a multiplier and divider AD534 is designed. A new smart time grating displacement sensor currently under development by us is used to provide experimental results for comparison with and without the AGC technology.
Electrical and Optical Properties of Potassium Niobate Grown by Vertical Bridgman Method
Authors: Takagi Takashi , Fujii Takashi , Ando Akira , Sakabe Yukio
Published: March 2009

Piezoelectric properties of potassium niobate (KNbO3; KN) crystal grown using the Vertical Bridgman method were obtained by a resonance-antiresonance method for a length extensional mode. The crystal was poled at 200°C under an electric field of 70 V/mm applied parallel to one of the spontaneous polarization axes. An electromechanical coupling factor (k31) of 0.248, mechanical quality factor (Qm) of 5700, piezoelectric constant (d31) of 9.6 pC/N, elastic compliance (s11E) of
4.02 pm2/ N, and constant (e33T/e0) of 42 were obtained. The optical absorption coefficient of poled crystal has been less than 1.0 cm-1 in the wavelength region of 400-1600 nm. Comparing these values with the reported one for TSSG-KN, indicated that our VB-KN was of good quality.
Photoluminescence Spectra of ZnO Films Doped with Li and Cl Atoms
Authors: Kobayashi Kenkichiro , Tomita Yasumasa , Maeda Yasuhisa , Matsushima Shigenori
Published: March 2009

ZnO films doped with Li and Cl atoms have been prepared by organometallic chemical vapor deposition method. In photoluminescence spectra of the doped ZnO films, strong emission appears at 376 nm which is slightly longer than that of free-excitons. As excitation intensity increases, a peak wavelength of the emission is shifted toward a shorter value. The emission near band-gap edge is assigned to radiative recombination via Li-Cl pairs.
Enhanced Piezoelectric Properties of Barium Titanate Single Crystals by Domain Engineering
Authors: Yako Koichi , Kakemoto Hirofumi , Tsurumi Takaaki , Wada Satoshi
Published: March 2009

Engineered domain configuration was induced into barium titanate (BaTiO3) single crystals, and the d33 piezoelectricity was investigated as a function of domain size. Prior to the domain engineering, the dependence of domain configuration on the temperature and the electric-field was investigated, and above Curie temperature (Tc), when the electric-field over 16 kV/cm was applied along [111]c direction, the fine engineered domain configuration appeared. On the basis of the above information, the 33 resonators with different domain sizes were successfully prepared. Their piezoelectric measurement revealed that the d33 of the 33 resonators with fine-engineered domain configurations were higher than those of BaTiO3 single-domain crystals. Moreover, d33 increased with decreasing domain sizes. The highest d33 of 289 pC/N was obtained in the BaTiO3 crystal with a domain size of 13μm.
Fabrication of Flat PZT Cantilevers through MEMS Technologies and Application to Optical MEMS
Authors: Kobayashi Takeshi , Tsaur Jiunnjye , Ichiki Masaaki , Maeda Ryutaro
Published: March 2009

Flat PZT cantilevers have been successfully fabricated from the Pt/Ti/PZT/Pt/Ti/SiO2/SOI multi-layered structure through MEMS technologies. A displacement of the tip of the cantilever driven at 6 V is measured to be 7.6 μm and the transverse piezoelectric constant calculated from the displacement is –103 pm/V. 1D optical scanners have been designed, simulated, fabricated and tested. The rotation angles of the mirror of the scanners were 60-70% of the simulated values.
Structure Analyses and Electrical Properties of Er-Doped ZnO Thin Films
Authors: Tanaka Shigeru , Ishikawa Yukari , Nezaki Dai , Okamoto Mitsuhiro , Shibata Noriyoshi
Published: March 2009

Er-doped ZnO thin films which emitted intense infrared light in the vicinity of 1.5 μm were investigated from points of view of the microstructure and electrical properties. The result of X-ray diffraction (XRD) pattern revealed that the crystal lattice of ZnO was apparently expanded by doping of Er ions. Electrical resistance in the direction of thickness of Er-doped ZnO film showed linear behavior, which was resemble to that of undoped ZnO film. Infrared light emission phenomenon of the film was related to the chemical / physical state of Er ions in ZnO matrix.
Interfacial Structure of GaN and InN Thin Films Grown on ZnO Substrates
Authors: Ohgaki Takeshi , Sugimura Shigeaki , Ryoken Haruki , Ohashi Naoki , Sakaguchi Isao , Sekiguchi Takashi , Haneda Hajime
Published: March 2009

Gallium nitride (GaN) and indium nitride (InN) films were grown on a zinc oxide (ZnO) single crystalline substrate with a (0001) orientation using molecular beam epitaxy. The interfacial structure and relaxation mechanism of the lattice mismatch at the nitride/oxide interface were investigated, particularly the effects of an (In,Ga)N alloy buffer layer on the interfacial structure of the GaN films. This layer significantly improved the crystallinity of the GaN films by gradually relaxing the lattice mismatch between the GaN and ZnO. In spite of the large lattice mismatch between InN and ZnO, InN films with high crystallinity were grown without an (In,Ga)N buffer layer. Structural analysis revealed that an InN layer with low crystallinity formed spontaneously during the initial growth stage, and this amorphous-like layer likely contributed to relaxation of the interfacial stress caused by the lattice mismatch.
Effects of Hydrolysis on Photochromic ZrO2 Precursor Solutions
Authors: Nishizawa Kaori , Miki Takeshi , Suzuki Kazuyuki , Tanaka Kiyotaka , Kato Kazumi
Published: March 2009

The UV-Vis absorption spectrum of ZrO2 precursor solution containing 4-(phenylazo)benzoic acid (C6H5N=NC6H4COOH) reversibly changed accompanied with reversible change of the spectrum of 4-(phenylazo)benzoic acid by light irradiation. However, the spectrum of ZrO2 precursor solution containing azobenzene (C6H5N=NC6H5) did not change accompanied with reversible change of azobenzene by light irradiation. Furthermore, the back reaction of ZrO2 precursor solution containing 4-(phenylazo)benzoic acid by visible light irradiation was suppressed even if the back reaction of 4-(phenylazo)benzoic acid has occurred by visible light irradiation, when the hydrolysis of ZrO2 precursor was suitably controlled.
Study on Improvement of Concrete Durability by Using High Performance Cement
Authors: Feng Nai Qian , Niu Quan Lin , Cai Jun Wang , Li Chong Zhi , Huang Ren Chang
Published: March 2009

Sulphate ion and chloride ion existed in the alkaline saline soils may cause serious
problems on the durability of reinforced concrete structures, while it is found that superfine mineral powder plays positive role in the precaution of the alkaline saline corrosion. A composite cement named high performance cement (H.P.C) composed of clinker, metakaolin and fly ash powder in appropriate proportions is developed with good performance in preventing concrete from alkaline saline soil corrosion. Mortar bar test and visual examination showed that the cement could
effectively control AAR and sulphate ion related expansion, and the charge passed tested according to ASTM C1202 was decreased to “negligible” level for concrete with W/B ratio of 0.3, and “very low” grade for concrete with W/B ratio of 0.45 and 0.55 when the high performance cement was used. Other properties such as low hydration heat and anti-freezing properties, as well as the uniformity of the fresh concrete (with no bleeding and segregation), made it an important material in the construction of concrete structure in alkaline saline soils.
The Research and Application of Self-Compacting Concrete
Authors: Yu Xin Wen , Gao Yu Hai , Hao Dong , Li Shu Zhi , Wang Lan Ying
Published: March 2009

Self-compacting concrete (SCC) has the environmentally friendly effect. The SCC can be prepared by using the technical approaches of “Double adding” (adding mineral admixtures and chemical admixtures and) low W/B (the ratio of water to composite binder). According to the requirements of design and construction, SCC of C30～C60 can be produced by selecting materials used and adjusting the amount and composition of composite binder, the dosage and composition of high performance chemical admixture as well as W/B, based on the reasonable component of SCC with volume. It had been applied successfully in some construction works in several, such as concrete filled steel pipe column and strengthening of concrete structure.
Study on Strength and Velocity of Longitudinal Wave of Low-Strength Concrete
Authors: Chen Wen Hua
Published: March 2009

A new kind of low-strength concrete is suggested to fill big caves to protect environment and ecosystem. The low-strength concrete have been studied regarding strength, wave propagation, water content, porosity, composition and cemented material by press experiments and sound wave analysis and shear tests. Those results show that: (1) the mechanical characteristics of low-strength concrete is complex; (2) strength of the low-strength concrete comes from interlocking of large-size crushed stones and bond of cement particle; (3) water content has significant effect (more than 30 percent) on velocity of longitudinal wave of the low-strength concrete and has little effect on strength; while effect of porosity of concrete on strength are more than 30 percent; (4) strength of
low-strength concrete are controlled by both the content of crust stones and content of cement and a relationship of strength and velocity of longitudinal wave is proposed.
High Performance Concrete with High Volume Fly Ash
Authors: Wu Jian Hua , Pu Xin Cheng , Liu Fang , Wang Chong
Published: March 2009

The emphasis of this paper is how to increase the 3-day and 28-day strength of high volume fly ash concrete. By some technical measures, such as improving the initial pozzolanic activity (3 day) of fly ash and decreasing the ratio of water to binding material and increasing the total dosage of binding materials, a concrete with the ratio of fly ash to binding materials between 50 %-70 % can be made. The fluidity of the concrete mix with large dosage of fly ash is very good and the strength at 3 day and 28 day are more than 42.5 MPa and 85 MPa respectively. By determining the pH value and the calcium hydrate content of the paste with large dosage of fly ash and accelerated carbonation test, it is shown that the resistance of the concrete to carbonization has been improved. The concrete with large dosage fly ash has good volume stability.
Early-Age Concrete Cover Crack and Its Effects on Concrete Cover
Authors: Huang Xin Min , Yang Cheng Yong
Published: March 2009

The influence of early-age crack on concrete cover was studied in this paper. Cracks in concrete increase the permeability of concrete, the section where cracking occurs should be treated as getting thinner. The formation and propagation mechanism of the early-age cover crack, and cover crack depth were two main topics, which were discussed mainly based on the dual boundary element method. At last, the ultimate analytical method was used to determine the minimum thickness of concrete cover.
Effect of Mineral Admixtures on Durability of Concrete Structure Subjected to Alkaline Saline Corrosions
Authors: Niu Quan Lin , Feng Nai Qian
Published: March 2009

Effect of a combination of alkali ions, sulfate ion and chloride ion on durability of
concrete structures was analyzed, and the effect of different mineral admixtures on deterioration caused by Cl- penetration, sulfate attack and alkali-silica reaction was investigated. It is shown from wetting-drying test that sulfate attack on concrete was greatly relieved in high Cl- concentration solution, but diffusion test showed that Cl- diffusion was accelerated by SO4 2- ion existence as SO4 2- may incorporate with aluminum phase prior to Cl- ion. Replacement of cement with mineral admixtures such as ground blast furnace slag (SL) and metalaolin (MK) were beneficial for absorption of Cl- ion penetrated into paste, while ASTM C441 showed that fly ash
(FA), metakaolin and natural zeolite (NZ) exhibited effectiveness in controlling Alkali-silica reaction (ASR).
Study on the Virtual Wheel and Grinding Process
Authors: Wang Wan Shan , Xu F. , Liang F. , Liu J. , Gong Ya Dong
Published: March 2009

In this paper the modeling method of object entity in the environment of virtual is
introduced and the three-dimensional simulation model of grinding wheel is established in Visual C++ programming language and OpenGL tool. The simulated experiment is made, which can indicate the effect of different parameters to grinding process. It proved the reliability and practicability of virtual wheel through comparing the simulation results and experimental data.
Raman Microspectroscopy Study on the Ground Surface of Monocrystalline Silicon Wafers
Authors: Zhang Y.X. , Kang Ren Ke , Guo Dong Ming , Jin Zhu Ji
Published: March 2009

In order to obtain higher ground surface quality of silicon wafers, it is essential to better understand the grinding mechanism. This study investigates the phase transformations in ground silicon wafer surface with the aid of Raman microspectroscopy. On the surface ground by #325 grinding wheel, the characteristic Raman peak of pristine Si (Si-I) is predominant and very small amount amorphous silicon (α-Si) is observed. It shows that short-range disorder or residual strains in the Si lattice are not caused, the material was removed by brittle mode. But the Raman spectra of surface ground by #600 and #2000 wheel demonstrate the presence of the α-Si and high-pressure phases (Si-III and Si-XII). It is confirmed that the Si momentarily exists in the metallic phase Si-II during grinding process. The Si-II is ductile and easily removed by ductile mode. The transformed phases of all ground wafers disappear after chemical etching. In general, the material can be removed by ductile or brittle mode. Which mode dominates is determined by the grinding condition.
Study on the Dependence of Glossiness on the Micro-Uneven of Natural Granite Surface
Authors: Dai Qiu Lian , Qin C.Q. , Xu Xi Peng
Published: March 2009

In this paper, three kinds of granite were lapped and polished by loose abrasives. Glossiness and surface roughness of the lapped and polished granites were measured and the surface morphologies were observed. The experimental results revealed that the readings of roughness were very discrete. High glossiness can be achieved only when the surface roughness is decreased to a certain level. The average surface roughness of the three kinds of granite after being finely polished can reach 0.02～0.04um. Further reducing of roughness has little effect on the glossiness because the existence of the defects, which prohibits the further increase of the glossiness.
Theoretical Research on Gear-Honing and Manufacturing Technology with Electroplated CBN Honing Wheel
Authors: Zhang Man Dong , Lv Ming , Ya Gang , Ma L.
Published: March 2009

The theory and effect of gear-honing are wholly different between electroplated CBN hard honing wheel and epoxy resinoid soft honing wheel. In the paper, through deeply analyzing the mechanical character and engaging situation of both plated CBN hard honing wheel and gear, the bending deformation, contact distortion and cutting depth are calculated at engaging point. At last, the manufacturing technology combining conventional CBN electroplating and thermal diffusion in vacuum to produce gear-honing wheels for hardened tooth is introduced. These are important to improve the machining accuracy and finish of hardened gear tooth surface.
Research on the Heavy Abrasive Belt Grinding Machine to Reduce Thickness of Engine Connecting Rod Head
Authors: Huang Yun , Huang Z.
Published: March 2009

The paper describes the heavy abrasive belt grinding technology and the conventional machining method to reduce thickness of connecting rod head, analyses the technique difficulties with the latter, brings forward a reasonable new method which can reduce thickness by heavy abrasive belt grinding, expatiates on the grinding result with the grinder which is designed by this method, finally summarizes and prospects to this new method.
Study on Application of SFD for Deep Hole Machining
Authors: Yu Tian Biao , Gong Ya Dong , Liu J. , Xu F. , Wang Wan Shan
Published: March 2009

Based on the shortcoming and deficiency of deep hole machining, a grinding wheel
spindle with squeeze film damper—SFD is design based on squeeze film damped theory. The motion differential equation of SFD grinding wheel spindle is constituted according to D’ Ale mbert principle，and a lot of simulated research has been carried out about the locus of grinding wheel spindle affect by SFD. Founded on the simulated result, the SFD grinding wheel spindle of internal grinder have designed, and the grinding experiments have been performed. Experimental result indicate that the rationality of design for SFD can make the vibration of the grinding wheel spindle
reduce 25% , and make machining precision of hole improve 20% , make work efficiency of the grinder raise 15%.
Research on NC Point-Grinding of the Curve Based on Normal Tracing
Authors: Wu Q.J. , Hu De Jin
Published: March 2009

This paper presents a new technology, which is the normal tracing, for NC point-grinding of the curve. The development of the technology is based on the simultaneous three-axis machining. By controlling the superposition between the rotary surface of the grinding wheel and the normal vector of the curve, point contact between them is realized. So grinding just like turning, the abrasive
machining of the complex curve is easy to be realized. The main advantage of the technology is the fact that it can not only reduce the deformation of the grinding wheel and simplify the NC programming, but also improve surface quality and profile accuracy. This paper builds the mathematic model of the normal tracing by analyzing the geometric property and the kinematic relationship between the wheel and the work piece. Then the control algorithm of the normal tracing is given and used in a new-type digital curve grinder successfully, MD9040 developed by ourselves.
Intelligent Monitor and Control System for Grinding Process
Authors: Liu Gui Jie , Gong Ya Dong , Wang Wan Shan
Published: March 2009

The intelligent monitor and control system for grinding process is proposed in this paper, it utilizes the nonlinear modeling theory and self-learning capability of neural network to setup non-liner mapping relations between grinding conditions and AE signals, and to realize grinding process intelligent monitor and control by picking-up grinding AE signals on line. Grinding quality can be monitored on-line, starting parameters for grinding process can be selected, on-line intelligent adjustment of grinding conditions also can bee realized by using this system.
Optimizing Design of the Helix Flute Grinding Parameters with a 6UPS Parallel Grinding Machine
Authors: Shen Xing Quan , Pei B.Q. , Zhu X.J. , Gao H.
Published: March 2009

The helix flute grinding was important to machine a complex revolving tool. The
geometric parameters (especial its rake angle, flute depth and flute width) have essential effect on the performances of the tool. Using the 6UPS parallel grinding machine developed from BEIHANG, especially after analyzing its special machining and structure features, this paper gave general analysis to all factors which will influence the flute shaping. According to the moving relationship between
grinding wheel and the tool, a simulation modeling system was established. This system could be adopted to optimize and quantitative design that influence parameters deeply. The parameters refer to the grinding wheel defluxion, the grinding wheel thickness, the grinding wheel offset position along the X direction, and the flute depth. Experiments were carried out to verify the influence results.
Development of an On-Line Bowl-Shaped Diamond Grinding Wheel Dresser
Authors: Shi Jia Shun , Cai Guang Qi , Hu Ming , Liang Q.Y.
Published: March 2009

In this paper, a new on-line diamond grinding wheel dresser, which is comprised of high-speed rotatory dressing wheel, micro-feed mechanism and control system, is presented. The principle of micro-feed machine working at requiring dressing depth, the control method of the dressing wheel speed adjusting and dressing depth, and structure of the control system are also introduced. The experiments we have done show that the dresser reach the goal of diamond grinding wheel on-line dressing.
Material Removal Model and Experimental Verification for Abrasive Jet Precision Finishing with Wheel as Restraint
Authors: Li Chang He , Cai Guang Qi , Xiu Shi Chao , Li Q.
Published: March 2009

The material removal rate (MRR) model was investigated in abrasive jet precision
finishing (AJPF) with wheel as restraint. When abrasive wore and workpiece surface micro-protrusion removed, the size ratio for characteristic particle size to minimum film thickness gradually diminishing, the abrasive machining from two-body lapping to three-body polishing transition in AJPF with grinding wheel as restraint. In the study, the material removal rate model was established according to machining mechanisms and machining modes from two-body to three-body process transition condition, and active number of particles in grinding zone were calculated and simulated. Experiments were performed in the plane grinder for material removal
mechanism and academic models verification. It can be observed from experimental results that the surface morphology change dramatically to a grooved or micro-machined surface with all the grooves aligned in the sliding direction in two-body lapping mode. On the other hand, the surface is very different, consists of a random machining pits with very little sign of any directionality to the deformation in the three-body machining mode. Furthermore, the material removal rate model was
found to give a good description of the experimental results.
The Effect of High Pressure Abrasive Water Jet Cutting Parameters on Cutting Performance of Granite
Authors: Huang Chuan Zhen , Hou Rong Guo , Wang Jun , Feng Yan Xia
Published: March 2009

The effect of cutting parameters such as water pressure, nozzle traverse speed and
standoff distance on the granite cutting performance as characterized by kerf width, kerf taper, and striation drag angle are researched with a series of experiments using garnetabrasive and ultra high pressure abrasive water jet numerical control machine tool. The relationship between system pressure and abrasive mass flow rate is also studied. The research results show that the abrasive mass flow rate is only proportional to water pressure and the effect of other cutting parameters is
not significant. It is found that an increase in water pressure is associated with an increased kerf width and a decreased kerf taper. The kerf width decreases with the enhancement of nozzle traverse speed, and resulting in a significant increase in kerf taper as the nozzle traverse speed increases. The kerf width increases with the enhancement of standoff distance, and hence it causes a significant increase in kerf taper at the standoff distance domain from 3mm to 4mm and then a little decrease in
kerf taper at the standoff distance increasing from 4mm to 5mm. The striation drag angle decreases with an increase in water pressure and a decrease in nozzle traverse speed.
New Method of Pre-Stress Grinding for Gearlike Cylindrical Surface of Linear Bearing
Authors: Ye Bang Yan , Liu Xiao Chu , Liu Jian Ping , Zhao Xue Zhi
Published: March 2009

Gearlike cylindrical structure can be used as outer ring of linear bearing for saving
material, but the machined surface quality and roundness of this kind of bearing is beyond control in cylindrical grinding and machining efficiency is low. To solve these problems, a new method of pre-stress grinding for gearlike cylindrical surface of linear bearing is put forward based on analysis on the principle of cylindrical centerless grinding. For implementing this process, a set of device with expanding mandrel for loading tensile pre-stress on bearing ring is designed and experiment of
through-feed grinding is carried out on centerless grinder. The experimental results show that this method can get fine quality of machined surface and increase the grinding efficiency greatly.
Molding Characteristics of Etched Surface Pattern in Polymers
Authors: Lee H.K. , Yang G.E. , Kim Hong Gun
Published: March 2009

Molding characteristics are presented for the surface pattern of polymeric materials in injection molding. They are related to the polymer properties and surface roughness of the etched mold. The polymer structure and the mold roughness can affect roughness deviation and surface duplication quality on polymers. Experiments are performed with respect to the surface roughness analysis. It is expected that the duplication properties can contribute to molding process of surface pattern in injection molding.
Effect of Lid Materials on the Solder Ball Reliability of Thermally Enhanced Flip-Chip Plastic Ball Grid Array Packages
Authors: Jen Yi-Ming , Chien Hsi Hsin , Lin Tsung-Shu , Huang Shih Hsiang
Published: March 2009

This research studied the thermal fatigue life for eutectic solder balls of thermally enhanced flip-chip plastic ball grid array (FC-PBGA) packages with different lid materials under thermal cycling tests. Three FC-PBGA packages with different lid materials, i.e., Al, AlSiC, and Cu, were utilized to examine the lid material effect on solder ball reliability. The cyclic stress/strain behavior for the packages was estimated by using the nonlinear finite element method. The eutectic solder was assumed to be elastic-plastic-creep. The stable stress/strain results obtained from FEM analysis were utilized to predict the thermal fatigue life of solder balls by using the Coffin-Manson prediction model. Simulation results showed that the fatigue life of the FC-PBGA package with a Cu lid was much shorter than FC-PBGA packages with other lid materials. The relatively shorter fatigue life for the FC-PBGA package with a Cu lid was due to the complex constrained behavior caused by the thermal mismatch between the lid, substrate and the printed circuit board. The difference was insignificant in the fatigue lives between the package with an Al lid and the conventional package.
Stress Engineering of Backend Metallization
Authors: Goh Chia Lan , Maury Alvaro , Yaacob Iskandar Idris
Published: March 2009

The backend structures of advanced VLSI (Very-Large Scale Integration) devices have become increasingly complex because of the need to combine several types of dielectric and metal layers in order to enhance device performance and/or reliability. For example, the inter-metal dielectric (IMD) stack of an aluminum-metallization device may consist of high density plasma (HDP) fluorine-doped silicate glass (FSG) for gap fill and RC-delay minimization, plus a silicon-rich oxide (SRO) cap to prevent aluminum attack from fluorine out-diffusion. Depending on the interplay between the tensile stress of the aluminum, and the typically compressive stress of the dielectric stack, the wafer may develop a large bow of either positive or negative sign. A large positive bow may negatively impact wafer handling during processing steps that use vacuum chucking, and can also
lead to excessive edge polishing during tungsten and oxide chemical–mechanical planarization (CMP) steps. This paper presents a methodology to reduce final wafer bow from ~+40 to ~-10 micron by a careful selection of SRO deposition conditions to achieve a stress value that results in flatter wafers.
Preparation of Hollow Polystyrene Nanocapsules via a Miniemulsion Polymerization Process
Authors: Kim Yang Soo , Sudol David , Dimonie Victoria , El-Aasser Mohammed
Published: March 2009

Hollow polystyrene nanocapsules with sizes of ~100 nm have been prepared
via a miniemulsion polymerization process by applying the encapsulation of a
nonsolvent (i.e., isooctane). Divinylbenzene has been added to styrene as a cross-linking comonomer in order to improve a structural stability of the hollow polymer capsules. Morphology variation of nanocapsules with concentrations of divinylbenzene and also isooctane has been studied using transmission electron microscopy analysis. Kinetic study on the miniemulsion polymerization of styrene in the presence of divinylbenzene and isooctane has been carried out using fractional conversion data determined by the gravimetric analysis.
Synthesis and Characterization of Iron Oxides Nanoparticles
Authors: Ang Bee Chin , Yaacob Iskandar Idris
Published: March 2009

Magnetic iron oxides nanoparticles were synthesized at room temperature using water in oil microemulsion process. This microemulsion system was prepared using HTAB (surfactant), noctane (oil), 1-butanol (cosurfactant) and aqueous salt solution of Fe2+ and OH-. The microemulsions were used as microreactors for controlling the growth of the particles. The nanoparticles were characterized using TGA, XRD, TEM, BET, DLS and AGM. X-ray diffraction analysis revealed that the magnetic nanoparticles could be directly formed at room temperature. It also showed that the particles were either maghemite (γ-Fe2O3) or magnetite (Fe3O4). TGA thermogram showed two significant weight losses at around 100°C and 250° C, which were caused by dehydration and burn off of the surfactant. The surface area of the magnetic particles measured using gas absorption and desorption technique was 105.43m2/g, which indicated the presence of particles of 21nm in length. The size measured by TEM and DLS was 105nm and 107.9nm respectively due to the formation of large aggregated clusters. The sample also showed strong magnetic properties with the value of Ms of 11.2 emu/g.
Computational Simulation of Tensile Mechanical Properties of Nano-Crystal Material Fe
Authors: Di Yu Xian , Ji Xin Hua , Li Lin'an , Qin Yu Wen , Chen Jin Long
Published: March 2009

The traditional finite element analysis method in conjunction with the atomic simulation technology was applied to study the mechanical properties of nanostructure materials. A phase mixture model in which nanocrystalline material is regarded as a mixture of crystalline phases and intercrystalline phases (grain-boundary, triple line junction and quadratic node) and pores is presented. The Morse potential function was used to simulate the nonlinear constitutive model of grain boundary phase of NC Fe. The effects of grain size and porosity were investigated in the literature. The calculated results are compared with previously published experimental data.
Development of a Soft Linear Motion Actuator Using Synthetic Rubber
Authors: Choi Hyouk Ryeol , Jung Kwang Mok , Jung Min Young , Koo Ja Choon , Nam Jae Do , Lee Young Kwan
Published: March 2009

As ElectroActive Polymers (EAPs) attract keen attentions from various engineering fields, they have been proven more beneficial over the traditional electromagnetic transducers. In the present paper, a new polymeric material that could be adopted for a dielectric elastomer actuator is introduced. The proposed synthetic rubber produces larger deformation at higher energy efficiency compared to previously known dielectric elastomers. A method for the material synthesis and a set of comparative testing of the material to the existing material are to be mentioned in the present work. In addition, benefits of actuators made with the proposed material are discussed.
Model of Damage Fracture and Damage Rheology for Jointed Rock Mass and Its Engineering Application
Authors: Zhu Wei Shen , Li Shu Cai , Zhang Q. , Qiu X.
Published: March 2009

This paper puts forward a damage-fracture mechanical model and a
damage-rheology mechanical model for the jointed rock mass of the high slopes in the ship lock area of Three Gorges Project. These two models are used to analyze the slopes’ stability. A comparison of the computed displacements at numbers of points on the slope surfaces with the results from 3-D analysis is also made. In addition, some computing results are compared with the in-situ measured ones, showing that the model proposed is basically reliable.
A Three-Dimensional Numerical Model for Simulating Deformation and Failure of Blocky Rock Structures
Authors: Jiao Yu Yong , Liu Quan Sheng , Li Shu Cai
Published: March 2009

This paper presents a three-dimensional numerical model for simulation of blocky rock structures based on static relaxation approach. The proposed method utilizes static equilibrium equations to calculate the displacements of blocks, compared to Newton’s second law applied by the traditional DEM. In order to obtain displacements simultaneously, the technique of global stiffness matrix is introduced in to form the global equilibrium equations. Because large displacements come from the accumulation of small displacement increments, an iteration procedure is adopted in the calculation. A C++ program is developed based on the proposed algorithm, and an illustrative example is computed for verification.
Numerical Simulation of Humidity-Stress in Unsaturated Argillite Tunnel
Authors: Chen Wei Zhong , Li Fei , Wu Guo Jun , Li Shu Cai , Shao Jian Fu
Published: March 2009

An extension of Hoek-Brown criteria to include unsaturated behavior of argillite in
porous medium is presented. The model is applied to simulate evolution of saturation degree in argillite and concrete in an experimental tunnel where field investigation of
thermo-hydro-mechanical response of argillite and concrete will be done. Based on the laboratory experimental data, two different flow rules of water relative permeability and water saturation degree were suggested. The general evolution rules of saturation degree in argillite and concrete with time considering the effects ventilation are obtained.
Mohr-Coulomb Model Considering Variation of Elastic Modulus and Its Application
Authors: Cui X.Z. , Jin Q. , Shang Q.S. , Liu S.T.
Published: March 2009

Mohr-Coulomb model is a perfect elastoplastic model. It only considers the variation of material strength with lateral compressive stress, but doesn’t consider the variation of elastic modulus with lateral compressive stress and stress level and this is accordant with the true characteristic of geological material. The elasticity modulus in Mohr-Coulomb model was modified by employing the processing method of tangential modulus in Duncan-Chang nonlinear elastic model. In modified
model, the stress-strain curve in elastic phrase behaves as hyperbola. In order to embed the modified model in FLAC3D program (Fast Lagrangian Analysis of Continua in 3 Dimensions), a preprocessing program was written and was employed to analyze numerically the bearing capacity of rigid piles loaded laterally.
3-D Network Simulation of Rock Joints and Permeability Tensor Analysis
Authors: Yang Chun He , Wang Guibin , Yin Liming
Published: March 2009

Based on the field geology survey data, the probability distribution function of joint aperture was analyzed and the availability of the fitting data was verified. The joint aperture data observed the previous fitted function can be generated in the process of joint simulation. The seepage of rock mass is proportional to the third power of joint’s aperture. It is much more reasonable and feasible to analyze the permeability tensor of rock mass with the previous generated data. At the same time, the method comprehensively considered the effect of joint’s orientation, aperture, scale
and their distribution.
Application of Sliding Block Computation Model in Stability Evaluation for Anchored Rockmass Slope
Authors: Zhang Qiang Yong , Zhang X.T. , Xiang W.
Published: March 2009

Based on the basic idea of Sara method, A sliding block computational model for the
anchored slope is established in this paper after taking into consideration the action of earthquake and influence of underground water as well as the supporting effect of rock-bolts . This model has been applied to stability analysis for the high slope project of a hydropower station and conclusions of significance to engineering design has been got.
Acoustic Emission Characteristics of Single-Edge-Notched Glass Fiber/Aluminum Hybrid Laminates
Authors: Woo Sung Choong , Kim Dae Joon , Choi Nak Sam
Published: March 2009

Acoustic emission (AE) characteristics have been studied for single-edge-notched monolithic thin aluminum (Al) plates and glass fiber/Al hybrid laminates. Traveling microscope was used for observing the plastic deformation and damage zone around the initial notch tip. Frequency characteristics of AE signals processed by fast Fourier transform (FFT) from monolithic Al could be classified into two different types. Type I signal had a relatively low frequency band of 96~260kHz,
while Type II signal had broad band frequencies of 192~408kHz. In case of glass fiber/Al hybrid laminates, AE signals with high amplitude (>80dB) and long duration (>2msec) were additionally confirmed on FFT frequency analysis, which corresponded to macro-crack propagation and/or delamination between aluminum layer and glass fiber layer. Also, distributions of the first and the
second peaks in frequency spectrum were related with local fracture behaviors of the hybrid laminates. AE source location determined by signal arrival time showed the extent of fracture zones. On the basis of the above AE analysis, characteristic features of fracture processes of single-edge-notched glass fiber/aluminum laminates were elucidated according to different fiber orientations.
A Novel Description of Thermomechanical Behavior Using a Rheological Model
Authors: Lee Keum Oh , Hong Seong Gu , Lee Soon Bok
Published: March 2009

Isothermal cyclic stress-strain deformation and thermomechanical deformation (TMD) of 429EM stainless steel were analyzed using a rheological model employing a bi-linear model. The proposed model was composed of three parameters: elastic modulus, yield stress and flow stress. Monotonic stress-strain curves at various temperatures were used to construct the model. The yield stress in the model was nearly same as 0.2% offset yield stress. Hardening relation factor, m, was proposed to relate cyclic hardening to kinematic hardening. Isothermal cyclic stress-strain deformation could be described well by the proposed model. The model was extended to describe TMD. The results revealed that the bi-linear thermomechanical model overestimates the experimental data under both in-phase and out-of-phase conditions in the temperature range of 350-500oC and it was due to the enhanced dynamic recovery effect.
Detection of Surface Flaw in a Homogeneous Ceramic Product by Resonant Ultrasound
Authors: Yang In Young , Kim Seung Hoon , Kim Young Nam , Yang Soon Ho , Beak Kyung Yun , Im Kwang Hee
Published: March 2009

This study evaluates cracks in a ceramic ferrule. When an optical fiber is connected to machinery, a ferrule is used to precisely set the optical axes of an optical fiber. A ferrule is a cylinder of 10.5mm in length and 2.5mm in diameter. The crack size of a ferrule can range from 10.40m to 32.35m. An acceptable ferrule must have no cracks. In this paper, we predicted and examined defects by Resonant Ultrasound Spectroscopy (RUS). To verify the data obtained from the experiment, we carried out simulation by explicit finite elements method, and compared the experimental results with simulation results. The average error range is 1~2 percent between the experimental resonant frequency of the acceptable specimens and the simulated FEM resonant frequency. Also, we compared the resonant frequencies of specimens with a crack with those of acceptable specimens. The histogram drawn from these data and the available mode surveyed were used to classify the specimens in the plant as either cracked or non-cracked specimens.
Model of Behavior of Materials with Delaminations under Hydrogen Embrittlement Conditions
Authors: Balueva A.V.
Published: March 2009

We consider fracture growth controlled by fluid diffusion into the fracture. If the
fluid is accumulated inside the fracture, after some incubation period, it starts growing under the pressure of the accumulated fluid. An important example is given by hydrogen induced cracking. Hydrogen absorbed by a metal is typically dissolved in the lattice in the proton form. Some of the protons reach the surface of a pre-existing or freshly created cracks where they recombinate with electrons and form molecular hydrogen in the crack cavity. Because usually the molecular form of hydrogen is thermodynamically more stable, this process leads to accumulation of gas hydrogen inside the crack. Then, the fracture often takes place even in the
absence of any external loading, that is, only under the excessive hydrogen pressure. Another example is given by heating of water saturated rock. If due to the heat diffusion, the water evaporates/boils inside the cracks, the pressure exerted by the vapor can cause the cracks to propagate, increasing the crack sizes by orders of magnitude.
Structural Integrity Assessment of Major Nuclear Components Using Probabilistic Fracture Mechanics
Authors: Lee Sang Min , Chang Yoon Suk , Choi Jae Boong , Kim Young Jin
Published: March 2009

The integrity of major components in nuclear power plant should be maintained during operation. In order to maintain the integrity of these components, complicated assessment procedures are required including fracture mechanics analysis, etc. The integrity assessment of components has been performed by using conventional deterministic approaches whilst there are lots of uncertainties to carry out a rational evaluation. In this respect, probabilistic integrity assessment is considered as an
alternative method for nuclear component evaluation. The objectives of this paper are to develop an integrity assessment system based on probabilistic fracture mechanics and to estimate the failure probability of major nuclear components containing a defect. The integrity assessment system consists of three evaluation modules which are first order reliability method, second order reliability method and crude Monte Carlo simulation method. The developed system has been applied to
evaluate failure probabilities of nuclear structural components such as steam generator tube and piping. The evaluation results showed a promising applicability of the probabilistic integrity assessment system.
Failure Analysis of Connecting Rod at Big End
Authors: Lee Su Young , Lee Seong Beom , Kim Heung Seob , Kim Tae Gu , Kam Moon Gab , Yoon Jung Whan
Published: March 2009

The connecting rod is one of the most important parts of an engine system. It fits in between the crosshead and the crankshaft and converts the piston’s reciprocating motion to rotary motion with the crankshaft. The connecting rod is subjected to a complex state of loading. High compressive loads and high tensile loads are due to combustion and connecting rod’s mass of inertia, respectively. This is why the connecting rod is the most stressed part of an engine system. If the engine is operating, connecting rod fails, this could cause a critical situation. Therefore, the connecting rod should be able to withstand tremendous load and transmit a great deal of power smoothly. In general, the failure occurs at the big end of connecting rod. Hence, the connecting rod’s big end corner radius was taken
as a design variable. Also, three dimensional finite element analyses were performed. From these results, the stress distribution was estimated and the value of the corner radius was optimized.
Compression Tests of Unidirectional Composite Laminates with Two Delaminations
Authors: Hwang Shun Fa , Chen Horng Ming
Published: March 2009

Compression tests are conducted on composite laminates consisting of 16
unidirectional carbon/epoxy layers with two through-width delaminations. Two types
of delamination length and location are considered. One is that a short delamination is located at the middle surface along the thickness direction and a long delamination is positioned between the second layer and the third layer. The other is that a long
delamination is located at the middle surface and the position of the short elamination
is between the second layer and the third layer. The results indicate that if the long
delamination is close to the surface of the laminate, the inner, short delamination has
no effect on the critical buckling stresses. However, the presence of inner, short
delamination may significantly change the critical delamination growth stresses. If the
short delamination is above the long delamination that is located on the middle surface, the presence of the short delamination may significantly reduce the critical buckling stresses. But its effects on the critical delamination growth stresses are minor.
Damage Evaluation of Subsurface Defect in Sandwich by Phase-Shifting Digital Shearography
Authors: Chen Jin Long , Sun Cuiru , Qin Yu Wen , Ji Xin Hua
Published: March 2009

When a sandwich structure is loaded in uniaxial in-plane compression the skin over the debonded region may buckle allowing further propagation of the debond, leading to structural collapse. Hence how to detect the shape and size of debonded defect, and to trace propagation trend of the defect are key factor in the process of damage evaluation of subsurface defect. In the paper, a nondestructive testing system is developed based on liquid crystal cell and Wollaston shearing prism. Nematic liquid crystal has the property of modulating the intensity and phase of light, and the intensity will not change during the phase modulating. According to this property, the
phase-shifting of digital shearography are performed successfully. The experimental results prove that we can not only perform detection of the defect size and shape in subsurface of sandwich structure, but also trace the further propagation of debonded defect because of local buckle. This indicates that the method of digital shearogrephy will offer an effective measurement tool to research the buckle behavior of debond defect in subsurface of sandwich under uniaxial in-plane compression.