RECENT ADVANCES IN STRAIN GRADIENT PLASTICITY
Keh-Chih HWANG and Tatsuo INOUE
Review Paper (Vol.4 No.4)
RECENT ADVANCES IN STRAIN GRADIENT PLASTICITY |
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Keh-Chih HWANG and Tatsuo INOUE |
227 |
General Papers (Vol.4 No.4)
LOCAL STRUCTURE OF Eu3+ IN BOROSILICATE GLASSES BY PHONON SIDEBAND SPECTRA |
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Zhidong YAO, Yong DING, Tokuro NANBA and Yoshinari MIURA |
239 |
PHOTOLUMINESCENCE ENHANCEMENT OF Er3+ IN PHASE SEPARATED BOROSILICATE GLASSES |
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Zhidong YAO, Yong DING, Tokuro NANBA and Yoshinari MIURA |
244 |
REMOVAL OF TOXIC SUBSTANCES OF CHLOROFORM AND BENZENE BY CARBONIZED WOODY MATERIALS |
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Shiro SAKA and Makoto DOI |
249 |
EVALUATION OF SOIL STABILIZED BY FERRUM LIME |
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Masashi KAMON, uanda Gu and Takeshi KATSUMI |
254 |
METHOD FOR PREDICTION OF DISLOCATION GENERATION IN SILICON SUBSTRATES OF SEMICONDUCTOR DEVICES |
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Hiroyuki OHTA, Hideo MIURA and Makoto KITANO |
261 |
MICROSTRUCTURAL STUDY OF MECHANICAL AND THERMAL PROPERTIES OF DIAMOND-LIKE CARBON |
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Yoshitada lSONO, Takeshi TANAKA and Nobuyuki TERAYAMA |
267 |
MODELLING OF SUPERELASTICITY OF SMA BASED ON THE EXPERIMENTALLY OBTAINED STRESS-STRAIN DIAGRAMS |
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Borut BUNDARA |
275 |
EFFECTS OF CONSOLIDATIONS ON MECHANICAL PROPERTIES OF KNITTED FABRIC REINFORCED THERMOPLASTIC COMPOSITES |
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Nguyen K. CUONG, Miyako INODA and Zen-ichiro MAEKAWA |
281 |
THE EFFECT OF WATER-ABSORPTION AND CRYOGENIC TEMPERATURE ON THE STRENGTH OF ArFRP |
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Sohei SHIROSHITA, Keiji OKAMOTO and Kenjiro KOMAI |
287 |
Short comunication (Vol.4 No.4)
ESTIMATION OF RESIDUAL STRESS WITH NON-UNIFORM DISTRIBUTION BY INDENTATION-FRACTURE METHOD IN CERAMICS | |
Toshihiko HOSHIDE |
294 |
Vol.4 No.4 ABSTRACT
RECENT ADVANCES IN STRAIN GRADIENT PLASTICITY
Keh-Chih HWANG and Tatsuo INOUE
Abstract:In the paper three kinds of framework of strain gradient plasticity recently developed and their applications are reviewed: strain gradient plasticity for CS solid-the couple stress-theory, strain gradient plasticity for SG solid, and mechanism-based strain gradient (MSG) plasticity. The applications are mainly focussed on the fracture problems. One way of accounting for material compressibility is suggested. The review is confined to the deformation theory version, though the flow theory version can be parallelly constructed. Key Words:Strain gradient, Plasticity, Couple stress, Higher-order stress, Fracture, Mechanism-based theory
LOCAL STRUCTURE OF Eu3+ IN BOROSILICATE GLASSES BY PHONON SIDEBAND SPECTRA
Zhidong YAO, Yong DING, Tokuro NANBA and Yoshinari MIURA
Abstract:In xNa2O (40-x)B2O3 60SiO2 (mol%) (x = 5, 10, 15, 20, 25, 30) glasses with 0.25 mo1% Eu2O3 as additive, the local structure around Eu3+ was explored by employing the phonon side band spectra of Eu3+ associated with 5D2 © 7F0 transition. It was found that the types and faction of the structural units around Eu3+ varied with glass composition. Moreover, the B-O Vibrational mode of BO3 unit exists around Eu3+ when x 15, which is not present in the same composition glasses free of Eu3+. A greatest asymmetry in the surrounding of Eu3+ occurs at x = 10, inconsistent with a maximum of some physical properties found in soditm borosilicate glasses at a Na:B ratio of about unity. In addition, various structural units possess different coordination preference to Eu3+. The highest theoretical microscopic optical basicity on the oxygen atoms in these units was advocated as a criterion of the coordination preference, which successfully elucidated a series of coordination preference phenomena occurring in silicate, borate and borosilicate glasses. Key Words:Eu3+, Phonon sideband, Local structure, Borosilicate glasses, Microscopic optical basicity.
PHOTOLUMINESCENCE ENHANCEMENT OF Er3+ IN PHASE SEPARATED BOROSILICATE GLASSES
Zhidong YAO, Yong DING, Tokuro NANBA and Yoshinari MIURA
Abstract:Two sodium borosilicate glasses containing Er3+ were isothermally heat treated for phase separation, followed by the formation of die droplet and interconnected textures, respectively. The effects of heat treatment condition and the phase separated texture on photoluminescence (PL) intensity of 4S3/2 ¨ 4Il5/2 transition of Er3+ were studied. It was found that the PL intensity increased with phase separation developing in both glasses. Moreover, die maximum PL intensities obtained by the phase separation in both glasses are 8.5 and 4.1 times as high as those in the respective untreated samples, the droplet texture being superior to the interconnected one. The mechanism of augmentation of the PL intensity was discussed in terms of the derived expression of he PL intensity. It was supposed that the induced interface after phase separation, causing notable increase in the radiative decay rate from the 4S3/2 to 4Il5/2 levels, was responsible for the significant enhancement in the PL intensity. Key Words:Er3+, Photoluminescence (PL), Borosilicate glasses, Phase separation, Interface
REMOVAL OF TOXIC SUBSTANCES OF CHLOROFORM AND BENZENE BY CARBONIZED WOODY MATERIALS
Shiro SAKA and Makoto DOI
Abstract:In a global expansion of environmental po11utions, trihalomethanes in water and aromatic toxic substances in air are both increasing. In this study, therefore, an effort has been made to develop carbonized woody materia1s to remove specifia11y these polluting materials and explore a potential of developing more functionalized new woody carbonized materials. It was found by elemental analysis that carbonized woody material prepared under hydrogen gas now was nope reduced, compared with that under nitrogen gas now, Particularly over 550 deg. Both carbonized woody materials were decreased in vapor adsorption of water with increasing the temperature, whereas adsorption of chloroform and benzene was instead improved and over 560 deg, carbonized woody materials under hydrogen gas now was superior to that under nitrogen gas now in their adsorption. Carbonized woody materials with these characteristics were found to adsorb chloroform in water and benzene in atmosphere effectively. These lines of evidence would support a concept that hydrogenative reduction of woody materials would be effective to enhance its adsorptivity against chloroform in water and benzene in atmosphere. Key Words:Carbonized woody materials, Polluting substances, Trihalomethane, Chloroform, Benzene, Vapor adsorptivity
EVALUATION OF SOIL STABILIZED BY FERRUM LIME
Aluminum Sludge for Road Base Materials
Masashi KAMON, uanda Gu and Takeshi KATSUMI
Abstract:Aluminum sludge is production waste from aluminum industry. The purpose of this paper is to investigate the effective utilization of this industrial waste as road base stabilization material. As ferrum lime stabilized soil has been used as road base material for a long time, mixing aluminum sludge with ferrum lime to form a new stabilizer may be beneficial to improve pavement performance as well as utilization of the waste. In order to assess engineering properties of the new stabilizer for its application to road construction, a series of laboratory tests such as unconfined compressive and bending tests had been carried out. Based on test results, both compressive strength and flexural strength of the stabilized soil can be promoted by addition of aluminum sludge, and in particular, the fracture surface energy, a Parameter which indicates the resistance of a material to cracking, can be improved significantly compared with ferrum |1ime or hydrated lime stabilized soils. It can be inferred that the durability of pavement is improved when stabilized with ferrum lime|aluminum. Key Words:Ferrum-aluminum lime,Stabilized soil, Cmpression strength, Flexural strength, Fracture surface energy
METHOD FOR PREDICTION OF DISLOCATION GENERATION IN SILICON SUBSTRATES OF SEMICONDUCTOR DEVICES
Hiroyuki OHTA, Hideo MIURA and Makoto KITANO
Abstract:In semiconductor devices, the stresses in the silicon substrate sometimes produces dislocations during high-temperature fabricating processes. Although most of the dislocations are generated at stress singularity fields, dislocation generation has been discussed without paying attention to stress-singularity matters. This paper shows that dislocation generation can be predicted considering stress singularity problem. In the experiments discussed, silicon substrates with stressed thin film bands, at whose edges the stress singularity fields were formed, were used as specimens. The strength of the singularities was controlled by changing the bandwidth. Data concerning whether or not dislocations appeared was compared with the values of the singularity parameter. This comparison was performed for two structures of thin films and at three temperatures, and the results show that the singularity parameter can be used to predict the generation of dislocations. Key Words:Dislocation, Silicon, Silicon nitride, Glide plane, Stress singularity parameter
MICROSTRUCTURAL STUDY OF MECHANICAL AND THERMAL PROPERTIES OF DIAMOND-LIKE CARBON
Yoshitada lSONO, Takeshi TANAKA and Nobuyuki TERAYAMA
Abstract:This paper describes the microstructural study of a chemical vapor deposited diamond-like carbon (DLC) thin film, ranging the thickness from 1 mm to 1.36 mm. the effect of deposition condition on the microstructure of the DLC film was analyzed by Raman spectroscopy. Increasing the bias voltage and the discharge current shifted the peak shift of G band toward high frequency and enlarged I(D)/I(G) ratio. Lower density films were obtained by lowering bias voltage at discharge current of 5A, but conversely higher density films by lowering bias voltage at 10A and 20A. The hardness and Young's modulus were directly proportional to density of the film. Molecular dynamics analyses gave a linear relationship between the bonding ratio, density and Young's modulus of the film. These analytical results qualitatively agreed with the experimental results. The thermal conductivity of the DLC films was discussed based on the molecular dynamics results. Key Words:Diamond-like carbon, Nano-indentation, Roman spectroscopy, Film Density, Hardness, Young's modulus, Thermal conductivity
MODELLING OF SUPERELASTICITY OF SMA BASED ON THE EXPERIMENTALLY OBTAINED STRESS-STRAIN DIAGRAMS
Borut BUNDARA
Abstract:Superelasticity is very applicable property of shape memory alloys, and for its wide implementation engineering practice it is important to have an efficient method which would enable designers to consider the material properties with sufficient precision in heir calculations. From the application point of view a new model is proposed in the paper. The general characteristic of the model is that modelling is based on the experimentally obtained stress-strain diagrams what is important for direct implementation of the material properties in design. With the model various tension and pure bending loading conditions were simulated numerically and the results are compared with the corresponding results obtained experimentally. Key Words:Superelasticity, Shape memory alloys, Numerical modelling, Tension, Pure bending
Nguyen K. CUONG, Miyako INODA and Zen-ichiro MAEKAWA
Abstract:A study was conducted on the effects of cooling conditions on flexural properties of aramid fiber knitted fabric (AFKF) and glass fiber knitted fabric (GFKF) reinforced thermoplastic polypropylene composites. To study these effects, composite laminates were fabricated under a molding pressure of 3 MPa far 20 min, then consolidated from the melt at different cooling conditions: rapid cooling i.e., quasi-quenching and gradual cooling. Flexural tests were carried out on specimens in two directions: Vale and course. Evaluation on thermal properties and morphology was studied using a differential scanning calorimetry (DSC). Flexural properties were little
THE EFFECT OF WATER-ABSORPTION AND CRYOGENIC TEMPERATURE ON THE STRENGTH OF ArFRP
Sohei SHIROSHITA, Keiji OKAMOTO and Kenjiro KOMAI
Abstract:Aramid fiber reinforced plastics (ArFRP) is being applied in severe service conditions, such as aeronautical or space environments. Therefore, it is necessary to elucidate their strength in various environments. In the present study, static tensile and fatigue tests of dry and wet specimens of ArFRP were carried out at room temperature and at cryogenic temperature, 77K. Two types of aramid fibers, du pont's Kevlar 49 and Teijin's Technora were used for the reinforcement. The fractured specimens were inspected under a Scanning Electron Microscope (SEM) after the tests and the fracture mechanisms were analyzed. The tensile strength of individual aramid fibers was also measured at the same temperatures. The effects of cryogenic temperature and water absorption on the strength of ArFRP and aramid fibers were made clear. Key Words:ArFRP, Static strength, Fatigue strength, Cryogenic temperature, Water absorption, SEM, Fractography