材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
53 巻 , 12 号
選択された号の論文の23件中1~23を表示しています
  • 松野 健次, 井上 正志, 渡辺 宏
    2004 年 53 巻 12 号 p. 1263-1266
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    A graft copolymer having poly (2-vinylpyridine) trunk (Mw=1.87×105) and sixty-eight polystyrene branches(Mw=4.98×103) was synthesized by anionic coupling method. The trunk span between branching points was about two times wider than the Rouse segment size for linear polystyrene. Dynamic birefringence and dynamic viscoelastic measurements around glass transition zone showed that the complex Young's modulus and the strain optical coefficient of the copolymer was very similar to those of linear polystyrene. The complex Young's modulus was separated into the rubbery and the glassy component moduli with the aid of the modified stress optical rule. The stress optical coefficients for the glassy and the rubbery components, respectively, agreed with those for linear polystyrene, meaning that no indication of microphase separation was rheologically detected over a whole range of frequencies studied. The effect of branching was not observed in the frequency dependence of the glassy component. The Rouse segment size calculated from the limiting modulus of the rubbery component at high frequencies was not affected by branching. Dynamic viscoelastic measurements around the terminal flow zone revealed that two relaxation modes were involved in the rubbery zone. The mode observed at short times was attributed to motion of polystyrene branches, and the other mode at long times was related to the motion of poly (2-vinylpyridine) trunk. Although Mw of poly (2-vinylpyridine) was much higher than the molecular weight of entanglement strands of linear polystyrene, the rubbery plateau zone was not clearly observed, possibly due to the dilution of entanglements by branching
  • 巽 大輔, 柳澤 正弘, 松本 孝芳
    2004 年 53 巻 12 号 p. 1267-1271
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Celluloses from different biological origins were blended to get solutions having various molecular weights and molecular distributions of the polymer. The flow curves of the cellulose blends lay between those of the original solutions. The high molecular weight component, tunicate cellulose, had remarkable effect on the long-time region of the viscoelastic functions of the blends. The weight fraction dependence of the zero-shear viscosity of the blends can be expressed by a linear mixing relation based on Ninomiya theory. The zero-shear viscosities of the blends are in proportion to the 5/2-th power of the weight-average molecular weight calculated from a linear combination of that of each component. This indicates that the zero-shear viscosity of the cellulose blends depends strongly on the molecular weight but scarcely on the molecular distribution.
  • 柏原 久彦, 高橋 雅興, 浦山 健治, 瀧川 敏算
    2004 年 53 巻 12 号 p. 1272-1275
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Effects of strains on rheological properties in the course of isothermal crystallization of polybutene-1 have been investigated. Dynamic viscoelasticity measurements made as a preliminary experiment showed that an induction period emerged on the plots of dynamic storage and loss moduli against time. The induction period was affected by the strain amplitude (γ) in the region of γ>0.03, but was independent of γ at γ≤0.03. The induction time for the dynamic measurement was independent from the frequency, but that for the steady shear measurement depended on the shear rate: the larger the shear rate, the shorter the induction time. This induction period was not governed by the total strain.
  • 渡部 豊光, 南齋 征夫, 肥留間 繁男
    2004 年 53 巻 12 号 p. 1276-1280
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Structural relaxation in cross-linked poly (methyl methacrylate) (C-PMMA) quite slowly cooled from the rubbery state to a quasi-equilibrium glassy state was studied at a temperature of 10°C less than the, glass transition temperature Tg (Tg-10°C=110°C). Constant-rate mechanical tension test and differential scanning calorimetry (DSC) technique were used for the observation of structural relaxation. At long times of storage at 110°C for quasi-equilibrium C-PMMA, a prominent structural relaxation was found as highly progressive developments of yield stress in the tension test and endothermic peak in the DSC measurement. Imposition of a tensile strain of 0.10 to the slowly cooled specimens induced short times structural relaxation modes. Yet, in spite of the imposition of finite strain, long times relaxation modes were almost the same to that of unstrained quasi-equilibrium C-PMMA specimens.
  • 小林 直, 溝口 真知子, 栗山 卓
    2004 年 53 巻 12 号 p. 1281-1286
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to understand distribution of TiO2 in LDPE molded by injection molding, acoustic velocity measurement was performed. As acoustic velocity is a function of elastic modulus and density of an object, it is expected to express the filler content that affects both elastic modulus and density. The specimen fabricated has step-like shape, and the thickness varies 1, 2, 3, 4mm in one molding. It was found that the acoustic velocities on a step were very scattered. The meaning of acoustic velocity was considered and it is confirmed that it is greatly affected by filler content. Therefore the scatter of acoustic velocity meant the heterogeneous distribution of TiO2 in LDPE. The filler contents showed large scatter around the steps, and filler contents were slightly changed from the gate to the end of flow in injection molding. It could be understood by acoustic velocity measurements that the distribution of filler content can be improved by adding surface treatment agent.
  • 正原 和幸, 山根 秀樹
    2004 年 53 巻 12 号 p. 1287-1294
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Rheological and mechanical properties of silicone resins filled with various silica particles were investigated before and after crosslinking. Both hydrophilic and hydrophobic particles were prepared from tetraethoxysilane and vinyltriethoxysilane, respectively in a liquid silicone matrix through a sol-gel process. Vinyl groups on the surface of the hydrophobic particles react with silicone resin. Rheological investigation for the uncrosslinked resin filled with particles revealed that the liquid polymer matrix containing hydrophilic particles has a strong three-dimensional structure. While the hydrophilic particle tends to form a three-dimensional structure, the hydrophobic particle in the liquid silicone matrix suppressed such tendency. Once matrix is crosslinked, although the three-dimensional structure of the hydrophilic particles gives rise to the slight increase in tensile modulus, the tensile strength and the elongation at break decrease. However, adhesion between hydrophobic particles and the matrix enhances the mechanical properties significantly.
  • 松田 成広, 廣瀬 真樹, 棚橋 満, 武田 邦彦
    2004 年 53 巻 12 号 p. 1295-1300
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Prior to the preparation of nano-scale composites, porous silica was prepared by the pseudo-phase separation method previously researched by the authors. The structure of the particle consists of two layers. One was the outer shape whose diameter was about 100μm and the inner structure was constructed by very fine particles. The diameter of the inner particles, formed by the agglomeration of the original silica particles, was about 20-30nm. The bonding strength between the inner agglomerated particles was controlled by the sintering temperature. The porous silica was blended with ethylene-vinyl alcohol copolymer and polystyrene in a Microlabo kneader. The diameter of the inner particles dispersed within the organic/inorganic composite was less than 100nm. Although the inner particles pull strongly against each other, the re-agglomeration was probably prevented by the insertion of the viscous polymeric materials between the inner particles. The relation between the force of agglomeration by the surface potential and the dispersion by the shear in the kneader is discussed and the fundamental characteristics are preliminarily studied.
  • 石川 朝之, 牧 育広, 越塚 朋和, 武田 邦彦
    2004 年 53 巻 12 号 p. 1301-1308
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    The thermal degradation and the flame retardancy of polycarbonate (PC) as one of the excellent flame retardant materials have been studied. Decabromodiphenylether (DBDPE), bisphenol-A biscrezel phosphate, red phosphorous, magnesium hydroxide, ammonium polyphosphate/pentaerythrytol and perfluoro-buthane-sulfonic acid potassium salt (PPFBS) were used as flame retardants. TGA and Py-GC-MS were used for analyzing the degradation and the assignment of the scission products. UL-test and cone calorimeter test were applied to observe the flame retardancy. Mg(OH)2 and ammonium polyphosphate (APP) made the molecular weight lower and the flame retardancy worse. It was due to hydrolysis of PC chain. Red phosphorous and PPFBS as well as DBDPE and organic phosphate which have been used as industrial flame retardants restrained the flammability. In particular, a very small amount of PPFBS showed an excellent effect on the flame retardancy measured by UL-test. However, the ignition time of PC blended with PPFBS measured by cone calorimeter was shorter than that of neat-PC. The relation between the flame retardancy and the thermal degradation has been analyzed. The generation of bisphenol-A as a scission product affected on the flame combustion time and the secondary decomposition of bisphenol-A was observed. The different thermal degradation paths were observed and simulated by computer in the case of the blends where the cleavage of isopropylidene in the chain took precedence over the hydrolysis of carbonate and crosslinking reaction was considered to follow the cleavage. The char on the surface was analyzed by elemental analysis and the chemical structure was discussed.
  • 日置 亜也子, 木本 正樹, 鈴木 義彦
    2004 年 53 巻 12 号 p. 1309-1312
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Titanium oxide (TiO2) is popular material as a white pigment, an ultraviolet rays absorbent etc. and recently TiO2 has attracted attention as a photocatalyst. We prepared mono-dispersed needle-like TiO2 particles by hydrolysis and condensation polymerization of titanium alkoxides in methanol-rich alcohol solutions with mild conditions; at atmospheric pressure and at 20-50°C. In the case of using other alcohol rich solutions, spherical particles were obtained or any particle was not obtained. H2O concentrations in solutions also affected the shapes of the particles. Using the solvent containing ≥0.2vol% H2O, the shape of the particles obtained was not needle-like but spherical. The needle-like particles were obtained only within the case where particles were prepared in methanol-rich solutions containing ≤0.1vol% H2O. The length and the aspect ratio of the particles were increased with increasing reaction period and reaction temperature. All of the particles obtained were amorphous before heating treatment. The particles possessed anatase structure after being heat-treated at 500°C for 1h. After irradiation with UV-light to the aqueous solutions of methylene blue added with the TiO2 particles, the absorbance of methylene blue decreased. The particles after heating were active as photocatalysts for decomposition of methylene blue in aqueous solutions and photocatalytic activities were dependent on the reaction conditions.
  • 青井 芳史, 神林 久栄, 小林 小百合, 上條 栄治, 出来 成人
    2004 年 53 巻 12 号 p. 1313-1317
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Anatase TiO2 with three-dimensional ordered macroporous structure has been fabricated by the liquid phase deposition method using colloidal template formed by self-assembling of polystyrene latex spheres of 199nm diameter as a substrate. The interstitial spaces of template were completely filled with TiO2 by the liquid phase deposition method. Heat treatment of the polystyrene-TiO2 composite film resulted in three-dimensional ordered macroporous TiO2. The obtained three-dimensional ordered macroporous TiO2 have sharp reflectance peak at 350nm indicating that the sample exhibits the behavior of a photonic crystal.
  • 田口 貢士, 吉本 昌広, 更家 淳司
    2004 年 53 巻 12 号 p. 1318-1322
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Silicon nitride (SiNx) films have been deposited at a substrate temperature ranged from R. T. to 800°C by a new radical-beam deposition technique. In order to reduce carbon incorporation into the film, hexamethyldisilazane was decomposed in a reaction with atomic nitrogen rather than in plasma directly in this technique. The carbon concentration of the film was estimated to be less than the order of 1019cm-3 based on secondary ion mass spectroscopy. The density of the film estimated from Rutherford backscattering spectroscopy (RBS) increased from 2.6 to 3.2g/cm3 with increasing substrate temperature. The resistivity and the dielectric constant of the film were evaluated to be 1013Ω·cm at 3MV/cm and 5.7 at 300kHz, respectively. This new technique is promising to obtain high-quality SiNx film by deposition without using SiH4.
  • 中村 俊一, 木本 恒暢, 松波 弘之
    2004 年 53 巻 12 号 p. 1323-1327
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Homoepitaxial growth on 4H-SiC {0001}-vicinal faces by chemical vapor deposition (CVD) operating at 1500°C is investigated. Homoepitaxy is successful for both 0.2° -off 4H-SiC (0001)Si and 0.7° -off 4H-SiC (0001)C faces, as well as a 3.5° -off (0001)Si face. In the case of (0001)Si faces, reduction of C/Si ratio during CVD growth and wafer re-polishing are effective to suppress formation of major surface defects like carrots and extending triangles, which, however, were not completely eliminated probably due to polishing damages remaining near the wafer surfaces. For (0001)C faces, the density of major surface defects, namely pits and extending triangles, decreases with increasing thickness of pre-growth thermal oxide up to 0.4-0.5μm. Thus, for (0001)C faces, proper thermal oxidation is effective to remove surface damages induced during wafer preparation that might cause the major surface defects.
  • 小池 一歩, 眞壁 勇夫, 矢野 満明, Erich KAUFMANN, Wolfgang HEISS, Gunther SPRINGHOL ...
    2004 年 53 巻 12 号 p. 1328-1333
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper describes molecular beam epitaxial growth of PbTe/CdTe quantum wells on (100)-oriented GaAs substrates and characterization of their photoluminescence spectra. Despite of the differences in crystal structure and thermal expansion coefficient between PbTe and CdTe, an intense mid-infrared emission was observed even at higher temperatures than 300K. The energy of the emission peak showed blue shift with decreasing well width and had a positive dependence on temperature in agreement with that of bulk PbTe, indicating that the emission resulted from electron-hole recombination in a type I quantum well. Multiple peaks, however, were found in the PL spectra, and analysis of the temperature dependence of PL peak energy revealed that the thermal mismatch between CdTe and PbTe promoted the peak separation. A PbTe/CdTe double quantum well showed a higher efficiency of the PL emission. These results indicate a promising application of this heterosystem to cleaved-edge cavity laser diodes operating at room temperature.
  • 森山 匠, 藤田 茂夫, 藤田 静雄
    2004 年 53 巻 12 号 p. 1334-1339
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Correlation between the quality of bulk ZnO substrates and the properties of homoepitaxial ZnO films grown by metalorganic vapor phase epitaxy (MOVPE) has been investigated. Two kinds of commercial wafers grown by different methods have been employed for the investigation. One of them exhibited (i) mosaic structure revealed by xray diffraction (XRD), and (ii) room-temperature photoluminescence (PL) featured by strong LO phonon replicas of free exciton emission. This reflects a dominant phonon scattering by defects, and/or emissions from impurities or defects. The other substrate showed (i) fine single crystal from XRD, and (ii) free exciton emission from the PL data at room temperature. PL peak position of the homoepitaxial film on the former substrate was lower than that of the free exciton emission. For the homoepitaxial film on the latter, (i) the PL peak at room temperature appeared at the energy position of free exciton emission, and (ii) the surface morphology was smoother than that of the film on the former substrate. We found that crystal quality of substrates significantly influenced the ZnO homoepitaxial films, and therefore it is a key to choose a high quality bulk ZnO substrate for homoepitaxial growth to make high quality epilayers contributing to conductivity control and device applications.
  • 中島 貴史, 藤田 隆洋, 中島 洋二, 中井 正人, 前元 利彦, 佐々 誠彦, 井上 正崇
    2004 年 53 巻 12 号 p. 1340-1345
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Electron interference effects at 4.2K were studied in nano-scale open dots fabricated in InAs surface inversion layers and in an InAs/AlGaSb quantum well. These structures were fabricated using AFM oxidation. We have observed periodic oscillations and aperiodic fluctuations on both systems. We investigated oscillation period using Fast Fourier Transform analysis. We found that for the InAs surface inversion layers the oscillation periods correspond to that of Aharonov-Bohm effect (AB effect) in agreement with the dot size. In contrast, for the InAs/AlGaSb quantum well, the deduced oscillation period did not correspond to the dot size. These results suggest that the observed AB oscillations are caused by the channel formed along the dot periphery due to the electron transfer from the InAs oxide to the InAs. Aperiodic fluctuations were characterized using correlation field analysis. For InAs/AlGaSb quantum well, correlation field was increased due to smaller skipping radius, as magnetic field increased. For InAs inversion layers, the correlation fields were not changed because the dot size is smaller than the cyclotron radius. The estimated electron phase breaking times tf were 1 psec and 10 psec for the InAs surface inversion layers and quantum well, respectively. The longer tf in InAs than that of GaAs systems at 4.2K indicates the importance of electron interference in InAs even at higher temperatures.
  • 永原 靖治, 喜多 隆, 和田 修, Henri MARIETTE
    2004 年 53 巻 12 号 p. 1346-1350
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    We have studied anisotropic exchange interaction in (CdTe)0.5 (Cd0.75Mn0.25Te)0.5 tilted superlattices fabricated by fractional monolayer growth onto a 1° off vicinal surface of Cd0.74Mg0.26Te (001). The (CdTe)0.5(Cd0.75Mn0.25Te)0.5 tilted superlattices have been confirmed by polarized photoluminescence to be equivalent to compositionally modulated quantum wires consisting of CdTe-rich and Cd0.75Mn0.25Te-rich wires. The Stokes shift for the CdTe-rich wires is remarkable at less than 10K. The large Stokes shift is due to exciton-magnetic polaron formation and non-magnetic localization. The exciton magnetic polaron formation is a result of the exchange interaction between excitons and Mn ions. The exchange interaction causes the large Zeeman shift of the CdTe-rich wires. The Zeeman shift depends on the direction of the magnetic field in the (001) plane; the Zeeman shift in the magnetic field parallel to the wire direction is smaller than that in the perpendicular field. We demonstrate reorientation of hole spins in the parallel magnetic field by polarized magneto-photoluminescence measurements. The reorientation of the hole spins causes the valence-band mixing, which results in the small Zeeman shift in the parallel magnetic field.
  • 青木 正雄
    2004 年 53 巻 12 号 p. 1351-1358
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 屋代 如月, 金井 雅之, 冨田 佳宏
    2004 年 53 巻 12 号 p. 1359-1364
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    In the present study, the deformation behavior of lamellae of polyethylene has been directly observed using the Atomic Force Microscopy in-situ bending test. A cantilever type specimen of polyethylene is bent on the AFM stage, and the surface profile is scanned in a time sequence. The rotation angle, shear and elongation of more than one hundred lamellae are quantitatively evaluated from the successive height profiles of AFM images. The result suggests that the deformation of each lamella is basically correlated with the global strain of scanned area, however, some lamellae show different behavior as “inclusion”. We also observed the onset of a craze in a time series, which reveals the following two facts; (1) the surface irregularity leads to the super-fibrils in a craze, (2) a super-fibril is found to break, shrink and annihilate in the later stages of deformation.
  • 岩本 剛, 澤 俊行, 佐々木 理洋
    2004 年 53 巻 12 号 p. 1365-1370
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    TRIP steels possess such favorable mechanical properties as high work-hardening characteristics, tenacity and strength due to strain-induced martensitic transformation during plastic deformation. However, appropriate mechanical properties are realized under quite restricted circumstances. To obtain the expected mechanical properties, more precise modeling of deformation behavior of TRIP steel is indispensable. Therefore, the constitutive equation for TRIP steel should be established based on micromechanics. Here, based on the Green function and selfconsistent approximation for homogenization, a strain rate field in the microregion and a macroscopic constitutive equation for TRIP steels are derived. Then, the tensile test of the plane strain block of SUS304 is simulated by FEM along with the proposed constitutive equation. Finally, the effects of the geometrical characterisitics of matensite particles on its mechanical properties are discussed.
  • 鎌倉 光利, 戸梶 惠郎, 石泉 有規, 長谷川 典彦
    2004 年 53 巻 12 号 p. 1371-1377
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper presents the fatigue crack propagation (FCP) characteristics and the fatigue behaviour of smooth specimens in an extruded AZ61 magnesium alloy. FCP tests and axial fatigue tests have been performed at the stress ratio of 0.05 and -1 respectively, in laboratory air at ambient temperature. Fatigue properties were evaluated and compared with those of a rolled AZ31 alloy in a previous report, and fracture mechanisms were discussed on the basis of crack initiation, small crack growth and fracture surface analysis. The relationship between FCP rate and stress intensity factor for large cracks consisted of two parts with different slopes, which became much more remarkable when FCP rates were characterized in terms of the effective stress intensity factor. This was attributed to a fracture mechanism transition because the fracture surface appearance was clearly different above and below the stress intensity factor where the slopes changed. The fatigue strength of the AZ61 alloy was higher than that of the AZ31 alloy and the fatigue strengths at 107 cycles were 60MPa and 50MPa respectively. However, the fatigue strengths characterized in terms of fatigue ratio were similar with a considerably low fatigue ratio of 0.22. Regardless of stress level, fatigue cracks initiated at the specimen surface in intergranular or transgranular mode due to cyclic slip deformation at a very early stage of fatigue cycling. The growth behaviour of small cracks was consistent with the FCP characteristic after allowing for crack closure for large cracks, but the operative micromechanisms were different between small and large cracks. Except for subsurface fracture occurred in the AZ31 alloy, the fatigue properties described above were basically the same as observed in the AZ31 alloy.
  • 泉 聡志, 三宅 威生, 酒井 信介, 太田 裕之
    2004 年 53 巻 12 号 p. 1378-1383
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    We have proposed a method to infer the initiation points and slip system of generated dislocations through the combination of FEM calculation and dislocation dynamics simulation. In order to reproduce accurate shape of dislocations observed by TEM, we adopted the Brown's core splitting in the same procedure that Schwarz did. We applied our method to dislocation motion in a shallow trench isolation (STI) structure. Both initiation points and slip systems of four kinds of generated dislocation could be identified. It was found that the observed dislocation loops had certain shapes, which would be determined by the balance between line tension and Peach-Koehler force originated from applied stress field. This indicates that the estimation of the resolved shear stress field would be also possible.
  • 斎藤 雄治, 栗田 政則, 石井 斉
    2004 年 53 巻 12 号 p. 1384-1391
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    An x-ray stress measuring method for a single crystal is proposed. This method can be applied to a orthorhombic single crystal having x, y and z crystal symmetry planes, the x-y plane being the specimen surface. In the plane stress state, residual stresses σ0x and σ0y can be determined using slopes M and M' of sin2ψ diagrams for the x and y measurement directions. Various stresses σa were applied to a silicon single crystal wafer specimen in longitudinal (x) direction using a four points bending loading device, and the peak positions of different diffraction planes were measured in the x and y directions by x-ray diffraction method. The measured peak positions of diffraction planes were plotted in the sin2ψ diagram for various applied stresses σa. Although the peak positions of different planes in the sin2ψ diagram deviated from the straight lines determined by the least squares method, the straight lines crossed at a point, and the slopes and intercepts of the straight lines varied linearly with the applied stress σa. The peak positions for a fixed ψ angle varied proportionally to the applied stress σa, and the measured proportionality constants ki and k'i in the x and y directions, respectively, almost agreed with the theoretical values.
  • 織田 伸吾, 佐藤 憲一, 服部 成雄
    2004 年 53 巻 12 号 p. 1392-1397
    発行日: 2004/12/15
    公開日: 2009/06/03
    ジャーナル フリー
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