bluuebunny/crossref_metadata_2025 huggingface dataset:
The Improvement of Wet Anisotropic Etching with Megasonic Wave
Authors: Che Woo Seong , Suk Chang Gil , Park Tae Gyu , Kim Jun Tae , Park Jun Hyub
Published: March 2009

A new method to improve the wet etching characteristics is described. The anisotropic wet-etching of (100) Si with megasonic wave has been studied in KOH solution. Etching characteristics of p-type (100) 6inch Si have been explored with and without megasonic irradiation. It has been observed that megasonic irradiation improves the characteristics of wet etching such as the etch rate, etch uniformity, surface roughness. The etching uniformity was less than ±1% on the whole wafer. The initial root-mean-squre roughness(Rrms) of single crystal silicon is 0.23nm [1]. It has been reported that the roughnesses with magnetic stirring and ultrasonic agitation were 566nm and 66nm [3]. But with megasonic irradiation, the Rrms of 1.7nm was achieved for the surface of 37µm depth. Wet etching of silicon with megasonic irradiation can maintain nearly the original surface roughness during etching. The results have verified that the megasonic irradiation is an effective way to improve the etching characteristics - the etch rate, etch uniformity and surface roughness.
Influence of Groove Slotting for Micro-Sensor Embedding on Smart Bearing's Mechanical Characteristics
Authors: Gao Hang , Lv Qing , Qu Li Gang
Published: March 2009

It is necessary to slot a groove on the outside of the bearing’s raceway in order to embed micro-sensor for smart bearing. Reasonable choice of slotting parameters for different type of bearings is one of key problems to be solved in smart bearing design. In this paper three-dimensional solid model and corresponding mechanics model for a segment of ball bearing’s out ring are built according to some reasonable simplification and supposition of boundary condition and loading status. Further more the influence of slotting parameters on smart bearing’s mechanical characteristics is studied with FEA method. Choosing 220 type of ball bearing as an example, theoretical analysis results of influence of slotting parameters on the maximum stress and deformation of outer ring are shown. The FEA results showed that micro-sensors for smart bearings should be manufactured flatter or the groove depth for micro-sensor embedding should be smaller soon as possible in order to insure the smart bearing’s original mechanical rigidity and strength.
Experimental Reliability Estimation and Improvement for a Wafer Level Vacuum Packaged MEMS Device
Authors: Choi Min Seog , Choa Sung Hoon
Published: March 2009

We carry out reliablity tests and investigate the failure mechanisms for wafer level vacuum packaged (WLVP) MEMS resonator using an accelerated degradation test (ADT). ADT is also used to estimate the mean life-time (or failure) of WLVP. The main failure mechanism of WLVP is found to be outgassing inside the package. Failure distribution of log-logistic is well fitted with the failure data from ADT, and Arrhenius model is used as a stress-life model because the main stress parameter is temperature. Acceleration factor (AF) for temperature levels is calculated and used to evaluate mean life-time of the WLVP after redesign. Finally the accuracy of ADT model is examined by verification test. The successful WLVP is achieved by reducing outgassing through the deposition of titanium coating inside the package as a getter material.
Analysis of Time-Dependent Degradation of a Micro-Resonating Structure with a Notch
Authors: Kim Jong Jin , Son Dong Il , Kwon Dong Il
Published: March 2009

Reliability is very important for the further development, commercialization and miniaturization of microelectromechanical systems (MEMS). In particular, concern arises about time-dependent degradation such as fatigue for MEMS with flexural elements because they are used in cyclic loading. This study investigated the time-dependent degradation of silicon micro-resonating structures. The test structure, designed and fabricated by micromachining, consisted of suspended
beams, shuttle, combs and electrodes. It was operated at resonance mode by applying AC voltage with a function generator and the change of resonant frequency was detected. The failure of a notched beam was detected by the saturation of the decrease in resonant frequency. The test structure showed
a decrease in resonant frequency with cycles that was attributed to stiffness degradation due to fatigue crack growth at the notch tip. By analyzing the test structure as a spring-mass system, the variation of stiffness of a notched beam with cycles was obtained from the resonant frequency. From this relation and the stiffness-crack relation, crack growth with cycles was calculated. Finally, the lifetime of the test structure was calculated and compared with experimental results.
Limit Load Interaction of Welded Piping Branch Junctions Subjected to Combined Internal Pressure and Bending
Authors: Xuan Fu Zhen , Li Pei Ning , Tu Shan Tung
Published: March 2009

Systematic detailed non-linear finite element (FE) analysis are described for limit load interaction of piping branch junctions subjected to internal pressure and bending. The results show that for the tees with a small diameter ratio, the limit load interaction closes to the linear expression; as diameter ratio d/D increasing, the interaction relationship tends to parabolic equation; for the piping branch junction with diameter ratio equaling to unit, the limit load combinations is approximately quadratic. Compared to the individual limit bending value, internal pressure slightly
increases the bending capability as it is in the range of 0.2£P/PL£0.4, especially for the cases of the main pipe with thinner wall. A closed limit load solution is obtained from the FE results through accommodating the geometrical parameter influence, and validated by using experimental results.
Application of Discrete Hamilton's Equation for Parallel Processing of Impact Problems
Authors: Koo Ja Choon , Kim H.S. , Choi Jae Boong , Kim Young Jin
Published: March 2009

Application of Hamilton’s theorem is limited to rigid body dynamics problems in spite of its benefit that always yield a set of first order differential equations as a model. From the fundamental formulation procedure, introduction of Hamilton’s principle to continuum problems differs from the traditional continuum modeling methodology that relies upon partial differential field equation. For the analysis of impact problems where highly nonlinear coupled models are norm, massively distributed computation schemes are usually employed and they significantly reduce computational cost and improve accuracy. With the parallel resources in mind, the present work applies Hamiltonian modeling approach to a shock propagation problem in continuous media. The formulated model which is in first order ordinary differential equations is efficiently calculated on a Beowulf based Linux parallel machines.
Effect of Strength Mismatch on Ductile Crack Initiation Behavior from Notch Root under Static Loading
Authors: An Gyu Baek , Ohata Mitsuru , Mochizuki Masahito , Bang Han Sur , Toyoda Masao
Published: March 2009

It has been well known that ductile fractures of steels are accelerated by triaxial stresses. The characteristics of ductile crack initiation in steels are evaluated quantitatively using two-parameter criterion based on equivalent plastic strain and stress triaxiality. It has been demonstrated by authors using round-bar specimens with circumferential notch in single tension that the critical strain to initiate ductile crack from specimen center depends considerably on stress triaxiality, but surface cracking of notch root is in accordance with constant strain condition. This study fundamentally clarifies the effect of strength mismatch, which can elevate plastic constraint due to heterogeneous plastic straining under static loading, on critical conditions for ductile cracking from the pre-notch root. In order to evaluate the stress/strain state in the pre-notch root of specimens, a thermal elastic-plastic finite element (FE) analysis has been carried out.
Influence of Dwell Time on Creep-Fatigue Crack Growth Behavior of P92 Steel Weldment at High Temperature
Authors: Lim Byeong Soo , Kim Bum Joon , Kim D. , Kim J.W. , Lee Dong Bok
Published: March 2009

In this study, the creep-fatigue crack growth behavior was investigated at 600°C under the maximum load with various dwell times. Test material was P92 steel (9%Cr-2%W) weldment. The creep-fatigue crack growth behavior of the HAZ(heat affected zone) and base metal was compared. The relationship between the crack growth behavior and dwell time was studied and it was characterized using ΔK and (Ct)avg parameters. The area fraction of micro-voids/cavities at the crack tip and fracture modes were examined and the relationship between crack growth rate and dwell time was investigated. The cycle dependant crack growth rate increased with the increase in dwell time. From the results of creep-fatigue test, the crack growth rate of the HAZ was found to be faster than that of base metal. As the dwell period increased, the intergranular fracture was observed along the crack growth path with the effect of creep during the dwell period.
Experimental Investigation on the Interface Properties Evaluation in Piezoelectric Layered Structures by Love Waves Propagation
Authors: Jin Feng , Kishimoto Kikuo , Inoue Hirotsugu , Tateno Takashi
Published: March 2009

The linear ultrasonic technique has been extensively used as a powerful, non-destructive test tool for reliability testing and failure analysis of electronic packaging. This is used most often in the inspection of defects such as delaminations, voids, or cracks through use of a SAM (Scanning Acoustic Microscope). Then, as the reliability level that is required of electronic packaging becomes higher and the thickness of package becomes thinner, the possible defect which needs to be detected becomes smaller. In the conventional SAM, however it is very difficult to detect small defects less than m µ 1 . 0 , such as micro-delaminations. In order to solve such a problem, this paper proposes a nonlinear ultrasonic method, where the nonlinearity caused by the effect of crack-face interactions is considered. The basic concept of this method involves harmonic frequencies that are generated in the transmitted ultrasonic wave due to the partial contact at the interface of micro-delamination. As an evaluation index, the nonlinear parameter dependent on the amplitude of the second order harmonic frequency component is obtained by spectral analysis of the transmitted signal. Experimental results show that the nonlinear parameter has good correlation with the micro-gap and the proposed method can detect the micro-delamination even less than nm 1 .
Nonlinear Ultrasonic Method to Detect Micro-Delamination in Electronic Packaging
Authors: Ha Job , Jhang Kyung Young
Published: March 2009

The linear ultrasonic technique has been extensively used as a powerful, non-destructive test tool for reliability testing and failure analysis of electronic packaging. This is used most often in the inspection of defects such as delaminations, voids, or cracks through use of a SAM (Scanning Acoustic Microscope). Then, as the reliability level that is required of electronic packaging becomes higher and the thickness of package becomes thinner, the possible defect which needs to be detected becomes smaller. In the conventional SAM, however it is very difficult to detect small defects less than m µ 1 . 0 , such as micro-delaminations. In order to solve such a problem, this paper proposes a nonlinear ultrasonic method, where the nonlinearity caused by the effect of crack-face interactions is considered. The basic concept of this method involves harmonic frequencies that are generated in the transmitted ultrasonic wave due to the partial contact at the interface of micro-delamination. As an evaluation index, the nonlinear parameter dependent on the amplitude of the second order harmonic frequency component is obtained by spectral analysis of the transmitted signal. Experimental results show that the nonlinear parameter has good correlation with the micro-gap and the proposed method can detect the micro-delamination even less than nm 1 .
Development on Stress Monitoring Method for Measurement of Cyclic Stress of Railway Axles
Authors: Kwon Seok Jin , Ogawa Kazuhiro , Shoji Tetsuo
Published: March 2009

In general, the S-N curve in railway axles was mainly carried out under 107-108 cycles, while the service area of a railway axle is 108-109 cycles. The strain gages using electrical resistance have been used to measure stresses in railway vehicle wheelsets. However, there are some problems with strain gages using electrical resistance for railway axles. For example, the measured data is for special or limited intervals only. Strain gage installation is complicated, that is, it requires lead wires
for measurement. The design of railway axles makes use of data that was obtained many years ago. The applied stresses in wheelsets running for a long time and in new railway vehicle wheelsets have not been studied clearly yet. It is necessary to carry out stress monitoring for more than 108 cycles to evaluate the safety of railway wheelset. Therefore, it is necessary to develop new stress monitoring techniques that can easily measure the working stress of the wheelset. In the present paper, the stress measurement technique of copper electroplating is considered because of its high potential for this purpose.
Analysis of the Test Parameters in the Shear Test of BGA Solder Joints
Authors: Kim Jong Woong , Park Sun Kyu , Jung Seung Boo
Published: March 2009

Ball shear test was investigated in terms of effects of important test parameters, i.e. shear height and shear speed, with an experimental and non-linear finite element analysis for evaluating the solder joint integrity of area array packages. A Pb-free solder composition was examined in this work: Sn-3Ag-6Bi-2In. The substrate was a common SMD (Solder Mask Defined) type with solder bond pad openings of 460㎛ in diameter. It could be observed that increasing shear height, at fixed shear
speed, has the effect of decreasing shear force, while the shear force increased with increasing shear speed at fixed shear height. Too high shear height could cause some bad effects on the test results such as unexpected high standard deviation values or shear tip sliding from the solder ball surface. The low shear height conditions were favorable for screening the type of brittle interfacial failures or the degraded layers in the interfaces.
Chip Warpage Damage Model for ACA Film Type Electronic Packages
Authors: Yang Se Young , Kwon Woon Seong , Lee Soon Bok , Paik Kyoung Wook
Published: March 2009

The use of anisotropically conductive adhesives (ACA) for the direct interconnection of flipped silicon chips to printed circuits (flip chip packaging), offers numerous advantages such as reduced thickness, improved environmental compatibility, lowered assembly process temperature, increased metallization options, cut downed cost, and decreased equipment needs. Despite numerous benefits, ACA film type packages bare several reliability problems. The most critical issue among them is their electrical performance deterioration upon consecutive thermal cycles attributed to gradual delamination growth through chip and adhesive film interface induced by CTE mismatch driven shear and peel stresses. In this study, warpage of the chip is monitored by real time moiré interferometer during –50oC to +125oC temperature range. Moreover, reduction in chip warpage due
to increase in delamination length is obtained as in function of thermal fatigue cycles. Finally, a new model to predict damage level of ACA package and remained life is proposed and developed.
'Micro-Meso-Process Theory' for Fatigue Source Evolution in Metallic Parts
Authors: Yao Mei , Yan Qingxian , Gao Yu Kui
Published: March 2009

This paper is an overview of our previous works [1-15]. A “micro-meso-process theory” [1, 3, 7] for quantitative analyses of the critical conditions of fatigue source evolution in metals and metallic parts has been established under comprehensive considerations of the processes occurring in individual weak grains (called as “micro-processes”) and the cooperative processes occurring in their surrounding grains (called as “meso-processes”), as well as the macro-scopical features of the fatigue behaviour. All these processes have stochastic and harmonizing characters, then it is concluded, that the most important process for fatigue source evolution is the formation of “cyclic meso-yielding zones” (CMYZs) under the cyclic loading, in which dislocation motions occur during
loading not only within some weak grains, but also within rather many grains surrounding them and, whereafter, during unloading or reverse loading, back motions of dislocations can occur along intersected slip plans in individual weak grains. The critical condition for fatigue source evolution is that the CMYZs get over some critical sizes and the apparent fatigue limit of metal or metallic part is
a stress / load needed for formation of such critical CMYZs at the position of weakest link. According to this consideration, a concept of surface / internal fatigue limit of metal is put forward [5, 6, 11, 12]; furthermore, the relationships of internal fatigue limit of metals to their small strain flow stress [8] are established and the procedures for prediction of the apparent fatigue limits of un- and surface-hardened smooth/notched specimens are proposed [9-15].
Effects of Environmental Factors on Stress Corrosion Cracking of Pipeline Steels
Authors: Yang Wu , Li Guang Fu , Guo Hao , Zhou Jian Jiang , Huang Chun Bo , Bai Jiasheng
Published: March 2009

Effects of some environmental factors on stress corrosion cracking (SCC) of pipeline steel X-70 both in near-neutral pH environments, including NS4 solution and several solutions containing main types of soil in the eastern part of China, and in high pH solution were studied by means of electrochemical measurement and slow strain rate testing (SSRT). The anodic polarization curves showed different features in near-neutral pH and high pH solutions in terms of active-passive transition behavior. In near-neutral pH solutions, the cracking mode was transgranular with the feature of quasi-cleavage, the susceptibility to SCC increased with decreasing potential, pH and temperature as well as increasing CO2, indicating a dominant mechanism of hydrogen induced cracking (HIC). In high pH solutions, the cracking behavior was similar to that in near-neutral pH solutions when the specimens were polarized at cathodic potentials, but quite different at anodic potentials. A comparison of the electrochemical behavior with the SCC potential region indicated a dominant SCC mechanism associated with anodic dissolution (AD) of X70 in high pH solution at anodic potentials. A preliminary experimental potential (E)-pH-SCC diagram has been established for X70 in near-neutral pH environments.
Evaluation of Mechanical Properties of Alumina Green Compact during Sintering at Relative Low Temperature
Authors: Nambu Shoichi , Enoki Manabu
Published: March 2009

Recently, ceramics was used extensively as structural materials and ceramics components became larger and more complex. Fracture sometimes occurs during firing because of large and complex shape, and this fracture interrupts manufacturing process. The simulation of sintering has been studied to prevent this fracture. However, it was difficult to simulate fracture process because there was little data on strength of green compact. It is necessary to measure strength during sintering in order to perform a useful simulation. In this study, we measured strength of two kind of alumina green compact during sintering. Three point bending test at elevated temperature was performed and strength was estimated at each temperature. A model for strength at relative low temperature was also proposed using the temperature dependence of specific surface area. Furthermore, fracture toughness test was performed and the relationship between strength and fracture toughness was obtained. Strength at relative low temperature increased with temperature. Fracture toughness was proportional to strength at the temperature range where materials demonstrated brittle fracture manner. Strength of each alumina was analyzed using this model.
Environmental Effects on Stress Corrosion Cracking Susceptibility of Cr-Mo Steel Tubes in Steam Generators
Authors: Kim Hyo Jin , Seo Do Won , Lim Jae Kyoo
Published: March 2009

Steam generator began having severe problems 20 years ago. The main causes were wastage, wear, loose parts, denting. These problems were solved by changing the water chemistry treatment method. Therefore these damage types were replaced by stress corrosion cracking on the inner surface of the tubes and most recently by intergranular attack and stress corrosion cracking on the external surface of the tube. Steam generator has experienced various forms of damage, most involving some kind of corrosion. Some of these problems have been virtually eliminated, others are successfully managed, but a few have not yet been brought under control. This study is to evaluate the environmental effects on the susceptibility to stress corrosion cracking in Cr-Mo alloy under simulated crevice condition. The test is simulated by producing drop, wet and evaporation process.
The XRF measurement is performed to investigate the amount and distribution of chromium carbide of grain boundaries. The tests are performed in the alkalic and acidic solution under various strain rates.
Environmental Fatigue Crack Propagation Behavior of Cast Stainless Steels under PWR Condition
Authors: Jeong Ill Seok , Kim Sang Jai , Song Taek Ho , Kwon Jong Jooh , Hong Sung Yul , Cho Sun Young
Published: March 2009

Environmental fatigue crack propagation of CF8M and CF8A steels used in the domestic nuclear power plants (NPPs) were investigated on the simulated pressurized water reactor (PWR) condition (temperature: 316°C, pressure: 15MPa). The test equipment for environmental fatigue (high temperature-high pressure loop, autoclave, load frame, and measurement system) was designed. As-received and 60-year aged specimens were used in the test. To compare with
environmental fatigue test, another test in the air condition was performed. The fracture surfaces of specimens were difficult to verify the fracture modes such as striation, inter-granular crack and cleavage and so on. As the ferrite content of CF8M is increased, more particles on the fracture surface were peeled.
Effects of Cold Working and Heat Treatment on Caustic Stress Corrosion Cracking of Alloy 800M
Authors: Huang Chun Bo , Li Guang Fu , Lu Zhan Peng , Zeng Jian Min , Yang Wu
Published: March 2009

The effects of cold working and heat treatment on caustic stress corrosion cracking (SCC) of mill annealed (MA) alloy 800M in boiling solution of 50%NaOH+0.3%SiO2+0.3%Na2S2O3 were investigated by means of microstructure examination, tensile test, X-ray stress analysis, SCC testing of C-rings, Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and metallography.
The microstructure of alloy 800M under tested conditions was austenite. With a train of 25% by cold working, the grains of alloy 800M became longer, yield strength (YS) and ultimate tensile strength (UTS) increased, elongation (δ ) decreased, residual stress and the susceptibility to SCC increased. With increasing temperature of heat treatment of alloy 800M with cold working, the grains became bigger , residual stress, YS and UTS decreased and δ increased, the susceptibility to SCC of alloy 800M decreased. In boiling caustic solution, SCC cracks on the surfaces of C-ring specimens polarized potentiostatically at –20mV/SCE initiated from pitting and propagated along grain boundaries. AES analysis indicated that the surface films on MA alloy 800M were enriched in nickel and depleted in iron and chromium.
Electric Properties of Sr1-xBi2+xTa2-yNbyO9 Ceramics
Authors: Takenaka Tadashi
Published: March 2009

The dielectric, ferroelectric and piezoelectric properties of strontium bismuth tantalate niobate, Sr1-xBi2+xTa2-yNbyO9 [SBTN10x(y)] ceramics were investigated. The samples were fabricated by a conventional ceramic fabrication technique. Curie temperature, Tc, increased with an increase in Nb concentration y, and Tc of SBTN2(y) showed two regions with different slopes that divided near y=1.0. The coercive field, Ec, of SBTN2(y) increased with the increase in y and the highest Ec of 90 kV/cm was obtained. SBTN2(0.6) and SBTN2(1.0) showed the highest coupling factor k33 of 0.17 in the SBTN2(x) system.
High-Rate Charge/Discharge Properties of Li Ion Secondary Battery Using V2O5/Carbon Composite Electrodes with Carbon Fiber
Authors: Kuwahara Akira , Suzuki Shinya , Miyayama Masaru
Published: March 2009

The charge/discharge properties of V2O5/carbon composites with controlled microstructures were investigated to achieve a high-rate lithium electrode performance. Composite electrodes were synthesized by mixing a V2O5 sol, carbon and a surfactant, followed by drying. V2O5/AB (acetylene black) and V2O5/VGCF (vapor-grown carbon fiber) composite electrodes showed high-rate charge/discharge properties only when they had very high carbon contents. V2O5/ (AB and VGCF) composite electrodes with controlled microstructures exhibited a discharge capacity of 245 mA·h·g-1 at a high current density of 40 A·g-1, which was approximately 70% of that at a low current density of 100 mA·g-1. The improvement in the high-rate charge/discharge properties was attributed to the short lithium ion diffusion distance, large reaction area and high electronic conductivity of those composite electrodes.
Fabrication and Optical Properties of PLZT Photonic Crystals Using a Sol-Gel Process
Authors: Aoki Tsuyoshi , Kondo Masao , Tsukada Mineharu , Kurihara Kazuaki , Kuwabara Makoto
Published: March 2009

Two-dimensional Pb0.865La0.09Zr0.65Ti0.35O3 (PLZT) photonic crystals with hexagonal arrays of air holes on (001) Pt-sputtered magnesium oxide substrates were fabricated using a sol-gel process with resist molds. The PLZT photonic crystals have a thickness of 200 nm, and the period of hexagonal array and the radius of air holes were 400 or 450 nm and 135 or 165 nm, respectively. The PLZT photonic crystals were primarily orientated along the c-axis. The strain hysteresis loop of the photonic crystals suggested that the photonic crystals are ferroelectric. Several peaks within range of wavelength between 500 nm and 1000 nm appeared in the optical reflection spectra from the cleaved facet of the photonic crystals. The peaks have polarization dependence and the frequency bands of the each peak were close to that of photonic band gaps (PBGs) expected by the calculations.
Self-Assembly of Perovskite Nanosheet Colloid at Room Temperature
Authors: Toda Kenji , Sato Hiroki , Sugawara Akira , Tokuoka Saori , Uematsu Kazuyoshi , Sato Mineo
Published: March 2009

We present a new method for soft chemical synthesis of perovskite materials. Perovskite K1-xLixNbO3 powders are produced by an ion-exchange reaction of layered perovskite precursor, K2NbO3F, with lithium chloride in water at room temperature. X-ray diffraction and X-ray fluorescent spectroscopic studies show that a mechanism of the ion-exchange reaction is a self-assembly between the perovskite nanosheets in aqueous solution.
Integration of Ceramic Catalyst on Micro-Hotplate of Thermoelectric Hydrogen Sensor
Authors: Choi Yeong Soo , Tajima Kazuki , Shin Woosuck , Sawaguchi Naoya , Izu Noriya , Matsubara Ichiro , Murayama Norimitsu
Published: March 2009

To integrate the ceramic Pt/alumina catalyst on micro-hotplate of micro-thermoelectric hydrogen sensor (micro-THS), a dispenser technique was used in this study. This micro-THS with the Pt/alumina catalyst is capable of sensing wide range hydrogen concentration of 50 ppm to 3 % at room temperature. For hydrogen/air mixture gas of 50 ppm, voltage signal is measured to be 0.03 mV at room temperature.
Study on Pervious Road Brick Prepared by Recycled Aggregate Concrete
Authors: Yan Han Dong , Huang Guo Hui
Published: March 2009

The influence of aggregate to cement ratio(A/C), sand to aggregate ratio(S/A) and water to cement ratio(W/C) on mechanical properties and pervious coefficient of pervious concrete prepared by recycled aggregate were systematically investigated in the paper. The optimum mix proportion by weight of pervious concrete prepared by recycled aggregate were 3.5 of aggregate to cement ratio, 0.15 of sand to aggregate ratio and 0.34 of water to cement ratio, resulted from an effect coefficient method. Flexural strength and compressive strength of pervious concrete road brick prepared by recycled aggregate concrete could satisfy the requirements of Chinese Standard for Concrete Road Brick (JC/T466-2000) and had good pervious performance.
Microstructure and Mechanical Properties of Shale Ceramsite Concrete
Authors: Zheng Xiu Hua , Zhang Bao Sheng , Jie Yuan , Chi Xu , Guo Yong Zhi , Kong Li Juan
Published: March 2009

The influence of pre-wetted time on strength of shale ceramsite concrete is
studied.Microstructures of both cement paste and interfacial zone between aggregate and paste of concrete are observed by scanning electronic microscope (SEM). The results show that, if the pre-wetted time of the shale ceramsite increased, the decline degree of early strength of concrete will be greater than strength at a longer age, and the growth rate of concrete strength may obviously
increase. The pore characteristics of concrete at different ages is examined. The change tendency of concrete strength at different ages is revealed from the point of view of microstructure.
Research of High Performance Artificial Reef for Breeding Abalone in Sea Water
Authors: Tang Ming , Li Xiao , Wang Tao
Published: March 2009

According to abalone’s growth characteristics, artificial abalone reefs are invented in this paper. The trace elements are added in concrete. The proportion is fixed by test. Ocean alga adheres to reefs with them very well. The craft, matching optimization, curing terms in the island environment and concrete long-term stability in the ocean current are studied to solve the durability of reefs in the marine environment. It shows the durability of fishing reef by high performance, high function, and ecological concrete technology is reliable. Its strength is still increasing for one year and no damage has been found. It is feasible to use the complex admixture, high-quality fly ash, ultrafine silicon powder, surface-soaking-into water-hating material made by our own, adhering-shaking-compact molding equipment made by ourselves and solar-energy-curing technology. Ten thousands of large-scale artificial abalone reefs have been done. A large amount of marine organisms covered the reefs only after 40 days using.
State-of-the-Art of Multifunctional and Smart Concrete
Authors: Sui Li Li , Liu Tie-Jun
Published: March 2009

This paper has summarized generally the progress of multifunctional, intelligent concrete, and the concept of intrinsic intelligent materials is put forward on the point of materials, in addition the research and development direction of multifunctional and intelligent concrete is advanced.
Study on Energy-Saving Residential Building Structures of Multi-Ribbed Composite Walls with High Performance Concrete
Authors: Zhang Yin , Yao Qian Feng , Ding Yong Gang
Published: March 2009

In this paper, the study and application of an entirely new energy-saving residential
building structure, whose wall is constructed with multi-ribbed composite wall and latent frame. Based on experimental research and theoretical analysis, it was found that the structure system had good seismic behaviors, strong structure adaptability and good energy-saving effect. At the same time, notable social and economic benefits have been shown in several examples.
Experimental Study on Stress-Strain Relationship of New-Old Concrete
Authors: Yin Jian , Li Yi Jin , Zhang Xiong , Zhou Shi Qiong
Published: March 2009

In this paper, full-range compression tests were conducted on prisms of Old concrete, New-Old concrete and High-Performance Rapid Repair Concrete (HPRRC) prisms The complete stress-strain curve of HPRRC incorporating PFAC (pulverized fly ash composite), Old concrete and New-Old concrete were obtained and compared with each other. The essential uniform deformation capacity of three kinds of concrete was verified with the experimental results. At the same time, the unified numerical expressions of the compressive complete stress-strain curves of the three kinds of concrete are put forward. The theoretical curves from calculation are in good agreement with the experimental curves.
Long Term Load-Carrying Capacity of Eccentrically Compressed Concrete Filled Steel Tubular Members
Authors: Han Bing , Wang Yuan Feng
Published: March 2009

Based on the creep model of CFST members constructed with the Elastic Continuation and Plastic Flow theory of concrete creep and the creep theory of concrete under multi-axial stresses, the paper studies the load-carrying capacity of eccentrically compressed CFST members with consideration of creep. Some eccentrically compressed CFST members’ long-term loadbearing capacity is calculated and corresponding results are compared with the load-carrying capacity without consideration of creep. According to the analysis of calculating results, it can be concluded that creep will decrease the load carrying capacity of eccentrically compressed CFST members, and it should be paid enough attentions in actual engineering.
Active Cutting Edges in Vitrified CBN Grinding Wheels
Authors: Cai R. , Qi H.S. , Cai Guang Qi
Published: March 2009

Wheel structure has a critical influence on grinding performance especially active cuttingedge density. Experiments were carried out to find out the relationshipbetween active and staticcutting edge density. It was found that there are many more active cutting edges in grinding thanexpected based on chip thickness formulae mainly due to wheel deflection in grinding.
Research on Genetic Optimization of Special Spiral Rod Grinding Process
Authors: Wang Wei , Yao Jian Shi , Cai Guang Qi
Published: March 2009

In the grinding process of special spiral rods, the actual feed rate is far below the allowable limit, resulting in great efficiency waste. To tackle the problem, this paper presents a controlling strategy which significantly improves rough grinding efficiency through changing grinding feed rate, enhances work-piece surface quality and shortens the processing time. Based on the establishment of the work cycle model of the special spiral rod grinding process, the strategy sets the grinding efficiency of each individual rod section as the objective function, thus via genetic algorithm realizes an optimal calculation on grinding feed rate variable and resolves the power and roundness constraint problem. Through computer simulation, an optimal grinding control plan is obtained which can help the grinding process to achieve overall optimization.
Experimental Study on Creep Feed Deep Grinding Titanium Alloy with Slotted CBN Grinding Wheel
Authors: Fu Yu Can , Xu Hong Jun , Sun Fang Hong
Published: March 2009

In order to improve the grindability of titanium alloys, the inhibition of chemical affinity
between abrasives and titanium alloys and cooling enhancement in grinding zone are carried out in this paper. Slotted electroplated CBN grinding wheels with optimum topography are used, and different grinding fluid supply systems such as conventional tangential spraying coolant supply, inner chamber coolant jet impingement, radial high-pressure coolant jet impingment are employed
in creep feed deep grinding experiments on titanium alloy (TC4). The experimental results show that high-pressure jet impingement has remarkable cooling effect. The temperature of the workpiece surface can be steadily kept below the critical film boiling temperature 120~130°C, while the workpiece surfaces is badly burnt with conventional coolant supply. The study will exploit an important research orientation that has great potential in high efficiency grinding. Further perfection of this study will not only enable us to increase the available material removal rate to a new level
but also solve the workpiece burn problem of the difficult-to-machining materials in high efficiency grinding.In order to improve the grindability of titanium alloys, the inhibition of chemical affinity between abrasives and titanium alloys and cooling enhancement in grinding zone are carried out in this paper. Slotted electroplated CBN grinding wheels with optimum topography are used, and different grinding fluid supply systems such as conventional tangential spraying coolant supply,
inner chamber coolant jet impingement, radial high-pressure coolant jet impingment are employed in creep feed deep grinding experiments on titanium alloy (TC4). The experimental results show that high-pressure jet impingement has remarkable cooling effect. The temperature of the workpiece surface can be steadily kept below the critical film boiling temperature 120~130°C, while the workpiece surfaces is badly burnt with conventional coolant supply. The study will exploit an important research orientation that has great potential in high efficiency grinding. Further perfection
of this study will not only enable us to increase the available material removal rate to a new level but also solve the workpiece burn problem of the difficult-to-machining materials in high efficiency grinding.
Prediction of Surface/Subsurface Crack Damage of Ground Ceramics
Authors: Lin Bin , Zhu Hong Tao , Han L. , Yu S.Y.
Published: March 2009

Ceramic is prone to engender surface/subsurface crack damage layer because of great grinding force and high brittle. Prediction of crack damage of ground ceramic is important for design and assessment of grinding process. In this paper, an investigation for surface/subsurface crack damage of ground ceramic is introduced. Depth of crack damage layer can predicted by calculating crack propagation balance size and a predicting model of crack damage layer depth is obtained.
Analysis of Dynamic Characteristics in Polishing Based on Two-Dimension Vibration of Fluid
Authors: Guo Zhong Ning , Yang Z.G. , Hang Z.G. , Yu Z.Q. , Yue T.M. , Lee Wing Bun
Published: March 2009

A novel polishing technique based on the two-dimension vibration of fluid is put forward to obtain ultra-smooth surface without damage. In operation, the polishing pad is replaced by fluid where fine abrasive particles are mixed, and the impact and grinding effect can be produced by means of the vibration of fluid and the relative motion of workpiece. It can achieve the ultra-precise polishing for all kinds of planes and curved surfaces. A finite element method is employed to analyze the dynamic behaviors, including vibration mode and harmonic response under the action
of the exciter, and the fluid field based on two-dimension vibration is simulated.
Experimental Research on Ultrasonic Lapping Al2O3 Engineering Ceramics Using Fixed Oilstones
Authors: Gao G.F. , Zhao Bo , Liu C.S. , Kong Qing Hua
Published: March 2009

Experimental researches on material removal rate and surface roughness of Al2O3
engineering ceramic guide-pulley lapping were carried out using W20 and W5 fixed oilstones by self-developed ultrasonic lapping tool both with and without ultrasonic assistance. Experimental results show that lapping speed, lapping pressure and grain size produce different effects on the lapped surface roughness and material removal rate. The material removal rate in ultrasonic lapping process is two times as large as that in traditional lapping, and the ground surface roughness is superior to that in common machining method. The material removal rate increases along with the
average diameter of grains and the lapping speed both in ultrasonic lapping and traditional lapping. In traditional lapping process the material removal rate becomes bigger along with the lapping force, while in ultrasonic lapping it gets the optimal value with the lapping force 450N. The value of lapped surface roughness increases along with the lapping speed in traditional lapping, on the contrary it decreases contrast to the lapping speed until 250rpm in the ultrasonic lapping. The value of traditionally lapped surface roughness decreases contrast to the lapping force, whereas it achieves the minimum with the lapping force 450N with ultrasonic assistance.
Mathematical Description of the Rotating Error Motion
Authors: Zhang Lei , Zhang Yu
Published: March 2009

According to the definitions of the CIRP Unification Document, The locus equations of the rotating center and the average rotating center are deduced, and then, the parameter equations of the rotating axis and the average rotating axis are obtained. All of above verify the definition of the rotating axis of the CIRP Unification Document in theory, and it is also proved clearly that the rotating axis and the average rotating axis are sole.
Thickness Effect of Pulse Shaper on Dynamic Stress Equilibrium in the NBR Rubber Specimen
Authors: Lee Ouk Sub , Kim Sung Hyun , Lee Jong Won
Published: March 2009

This paper presents an experimental finding in the Split Hopkinson Pressure Bar (SHPB) technique to obtain a better compressive stress strain data for rubber materials. An experimental technique which modifies the conventional SHPB has been developed for measuring the compressive stress strain responses of materials with low mechanical impedance and low compressive strengths such as rubber. This paper uses an all-polymeric pressure bar to achieves a closer impedance match between the pressure bar and the specimen materials. In addition, a pulse shaper is utilized to lengthen the rising time of the incident pulse to ensure stress equilibrium and homogeneous deformation of rubber materials. It is found that the modified technique can determine the dynamic deformation behavior of a rubber more accurately.
Design and Analysis of Micro Electrostatic Deformable Focusing Mirror Actuated by Hemispherical Electrode
Authors: Chang Pen-Lun , Lin Meng Ju
Published: March 2009

Deformable focusing micromirror is one of the important optical MEMS devices. The focusing length is determined by the profile of the micromirror surface. For uniform deformation, based on bulk microfabrication of isotropic etching and wafer bonding, a novel micro electrostatic deformable focusing mirror actuated by hemispherical electrode is designed and analyzed. Due to the coupling between elastic and electrostatic force, numerical method of finite element using ANASYS software is used to analyze the deformations and stresses of different structure sizes. The phenomenon that structures deform abruptly fast due to nonlinear increasing electrostatic force called pull-in is also discussed. Using the least square method, the profile of micro focusing mirror can be curve fitting as a parabola. And the focal length can be obtained. The results show deformation increases nonlinearly as applying voltages increasing. The stresses increase linearly when thickness also increase but nonlinearly when radius of mirror increases. The maximum stress happens in the region of bounded. The focal length decreases quasi-linearly as applying voltage increases. The mirror sizes and gaps have effect on pull-in voltages. Larger gap and smaller mirror radius will cause larger pull-in voltage.
On the Damage Evolution of 3-D Hydrous Cracks through CT Tests
Authors: Li Shu Cai , Zhu Wei Shen , Jiao Yu Yong , Jian H.
Published: March 2009

By using the real-time CT (computerized tomography) unit with specially developed water-injection loading apparatus, several failure tests of single-crack concrete specimens with interstitial water pressures under triaxial compression were conducted. The complete failure process: the closure, the initiation of new damage area, the secondary closure, as well as the crack propagation of the specimens were simulated. The CT images at each stage, the CT numbers and the comparison among different sections in the specimens were obtained. Based on the observed results, the role of compressive pressure in damage and propagation of hydrous crack can be intuitively revealed, and the characteristics of damage-evolution of cracks in brittle material can be better understood at meso-level.
3-D FLAC Numerical Analysis of Rheological Character and Stability of Underground Caverns Surrounding Rock Mass of Xiao Langdi Key Water Control Project
Authors: Zhu Wei Shen , Liu Jian Hua , Li Shu Cai
Published: March 2009

A brief description is given to the visco-plastic constitutive model of 3-D FLAC
software and some treating methods for the numerical analysis. The excavation steps and the exerting time of excavation loads are determined in the light of the real construction process. The rockmass mechanical parameters are determined according to back analysis of in-situ measured displacement data. The analysis results of displacement and stability of the opening complex surrounding rocks in the construction process and in a long period of time after excavation completion are given.
Damage Detection of a Gear with Initial Pitting Using the Zoomed Phase Map of Continuous Wavelet Transform
Authors: Lee Sang Kwon , Shim Jang Sun , Cho Byung-Og
Published: March 2009

Impulsive vibration generated by localized gear damage can be used as an indicator for damage detection. Local damage induces an abrupt increase of the amplitude and phase lag of the impulsive vibration signal measured on the gearbox. Relatively large damage like “tip breakage” can be easily detected by the amplitude map of CWT (continuous wavelet transform) for the impulsive vibration signal measured on the gearbox. However, minor damage like “initial pitting” cannot be detected with the amplitude map. To overcome this problem, in this paper we take into account the phase map for a damage signal. The zoomed phase map of CWT is successfully applied to the detection of minor gearbox damage.
Damage Tolerance Analysis on Repaired Fuselage Skin
Authors: Legowo Dibyo , Susena I Wayan , Tambunan Sharudin
Published: March 2009

This paper discussed about the method used by operator to perform damage tolerance analysis for repaired fuselage skin. Skin damage may be caused by accidental damage or fatigue crack. Some element needed for damage tolerance analysis and the method to develop load spectrum will be discussed briefly. Therefore, this paper will describe a case study of damage tolerance analysis on repaired fuselage skin of narrow body jet aircraft.
Acoustic Emission as a Tool of Fatigue Assessment
Authors: Han Kyung Seop , Oh Kwang Hwan
Published: March 2009

A series of laboratory investigations concerned about fatigue assessment with acoustic emission method was presented. Fatigue aspects including cumulative fatigue damage, fatigue crack growth and creep-fatigue interaction were considered. As a basic approach, residual strength and acoustic emission characteristics of fatigue damaged materials were considered from the nominal stress-life (S-N) viewpoint. Acquired signal indicated that counts emission quantity can be a good measure of cumulated fatigue damage. In the fatigue crack growth approach, interrelationship between acoustic emission parameter and stress intensity factor was examined with different stress level and crack length. Experimental results were somewhat scattered since sensitive characteristics of acoustic emission method. However, their empirical relation indicated that counts rate correlated with fracture mechanics parameter. Finally, acoustic emission application was extended to the creep-fatigue interaction at elevated temperature. Emission response under each damage mode was compared and characterized. Based on these characteristics, creep-fatigue interaction was evaluated by use of acoustic emission parameter. Overall investigations concluded acoustic emission is very effective tool of fatigue assessment.