材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
67 巻 , 9 号
選択された号の論文の12件中1~12を表示しています
論文
  • 田原 和彦, 松岡 英毅, 甘中 将人, 喜多 隆
    2018 年 67 巻 9 号 p. 829-833
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    We developed a heterodyne interferometry system cancelling the noise caused by a light source using a pair of heterodyne interferometers. The interferometry is one of the powerful tools to precisely measure the flatness of a polished semiconductor wafer. Generally, the noise caused by a light source affects the change of distance measured by interferometers, and it is difficult to avoid the noise by filtering a lock-in-amplification process. Here, we demonstrate that a pair configuration of interferometers synchronizing each other dramatically cancels the noises. The noise cancelling has been conducted by replacing the arrangement of the modulation frequency of two light waves producing an interference signal in one and the other interferometer each other. Utilizing these noise-cancelling heterodyne interferometers, we characterized the flatness of a polished silicon wafer. The precision has been improved 16% by the noise cancelling, and the system has enabled the measurement of the wafer flatness with repeatability of 0.32 nm.

  • 原田 宜明, 笠田 洋文, 安東 孝止, 阿部 友紀, 市野 邦男
    2018 年 67 巻 9 号 p. 834-839
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    Operating-current-pulse-width control (OCPWC) has been applied to the operation of white-light-emitting diodes used for plant growth. Plants were grown under light form LEDs driven by pulsed current using OCPWC as well as DC. Plant growth, i.e., the difference in the weight of a plant before and after the growth was found to be roughly proportional to the average current (and thus optical output power). In particular, when the LEDs were driven with an average current being 1.5 times higher than the standard condition, plant growth results in 1.6 times higher than the case for DC operation with the standard current. In addition, even after the operation for more than 900 hours with the 1.5 times current, the output power from the LEDs remained unchanged. These results suggest that OCPWC enables high power operation of LEDs suppressing degradation, and that the proposed technique is useful to increase plant growth per a facility and to reduce the production cost of plants.

  • 竹市 祐実, 三谷 展弘, 宇野 和行, 田中 一郎
    2018 年 67 巻 9 号 p. 840-843
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    We fabricated field-effect transistors (FETs) using ammonium sulfide-treated PbS colloidal nano-dot (CND) films. After the ligand molecules were removed from the CNDs by the ammonium sulfide treatment, many cracks were observed in the atomic force microscope image of the PbS ND monolayer that was formed by horizontal lifting method. Those cracks were filled and almost disappeared after we repeated the formation of the PbS CND monolayer and removal of the ligand molecules for three times. The FETs fabricated with the cracked PbS ND films exhibited serious bias stress effect and very low hole mobility of 5.6×10-5 cm2V-1s-1, which were attributed to the carrier traps existing on the NDs surface. On the other hand, the carrier mobility of the FETs with the crack-free PbS ND films was improved to be 1.1×10-3 cm2V-1s-1 because the cracks were filled and the trap density was significantly reduced.

  • 鎌田 大輝, 高田 賢志, 吉村 武, 藤村 紀文
    2018 年 67 巻 9 号 p. 844-848
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    Discovery of ferroelectric behavior of HfO2-based thin film is attracting much attention as a material applicable to FeFET based on the non-destructive operation with low power consumption and which obeys the scaling rule. For application to FeFET it is an important to grow orthorhombic HfO2 directly on Si substrate without buffer layer. In this paper, the crystal structure and the growth process of HfO2:Y epitaxial films on (001) Si substrate by pulsed laser deposition method are discussed. The effect of the O2 gas pressure and laser power for ablation on the crystal structure, the lattice parameters and the growth process are studied. It is revealed that the epitaxial HfO2:Y films can be obtained by controlling the oxygen pressure before deposition and active O* species in plume during deposition.

  • 小池 一歩, 村上 聡, 岩田 知也, 亀井 龍真, 矢野 満明
    2018 年 67 巻 9 号 p. 849-853
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    This paper describes characteristics of the tungsten trioxide (WO3) films fabricated on a glass substrate by a sol-gel spin-coating method. Ammonium meta-tungstate (AMT) and poly-vinyl alcohol (PVA) were used as the solute and stabilizer materials, respectively. The advantage of AMT is the high solubility in water, giving the capability for highly concentrated and alkali-metal-free aqueous solution. The fabricated films were characterized by x-ray diffraction, atomic force microscopy, optical transmittance spectroscopy, and Hall-effect measurement. By sintering the spin-coated solution in air, α-axis oriented orthorhombic-phase polycrystalline WO3 flat films were obtained with a bandgap energy of ∼2.8 eV and a relatively high electron mobility of ∼30 cm2/Vs. These results indicate that the sol-gel spin-coating method can be promising for the fabrication of semiconducting WO3 films to apply electronic devices.

資料
  • 高木 節雄, 増村 拓朗, Fulin Jiang, 土山 聡宏
    2018 年 67 巻 9 号 p. 855-860
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    Elastic anisotropy of polycrystalline metals can be evaluated by the difference in diffraction Young's modulus of each crystal plane {hkl} and the values of Young's modulus are theoretically calculated applying the stiffness; C11, C12 and C44 to the Reuss and Voigt model. In this paper, the values of diffraction Young's modulus E*hkl are calculated by the Reuss-Voigt average model for pure iron (bcc), austenitic steels (fcc), nickel (fcc), copper (fcc) and aluminum (fcc) and then the Young's modulus ratio ωhkl=(E*hkl/E0) is proposed to evaluate the relative elastic anisotropy. Here, E0 denotes the value obtained by the Voigt model. The value of E0 can be estimated from the experimentally obtained Young's modulus Em for polycrystalline metals by the equation; E0≒1.13Em. It was also found that there is good correlation between the anisotropy parameter Ai (=2C44/(C11-C12)) and ωh00=(E*h00/E0).

論文
  • 伊藤 潔洋, 濱田 泰輔, 荒井 正行
    2018 年 67 巻 9 号 p. 861-868
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    Fan blades and turbine blades in a jet engine are seriously damaged by high velocity impingements of bard, dust, volcanic ash, and metallic fragment, etc. onto these surfaces, which is called foreign object damage (FOD). Finite element method (FEM) is, generally, used for estimation of indent size and residual stress distribution resulting from the FOD caused on a metallic substrate. In order to estimate the FOD of a metallic substrate more easily, an estimate equation for the FOD (EFOD) is developed from a simple theoretical model based on energy conservation under high velocity impingement of a spherical particle onto a metallic substrate. In this study, a radius of crater formed on the surface was focused on. The EFOD was formulated based upon energy conservation before and after impingement phenomena. The Johnson-Cook constitutive equation was also employed to introduce effects of plastic strain and plastic strain rate, i.e. work hardening and strain rate hardening, into the EFOD. The plastic strain and plastic strain rate developed into a substrate were evaluated using FEM and formulated as functions of impact velocity, radius of particle and radius of crater. The validity of the EFOD was checked by comparing with the results of both FE analysis and experiment. It was confirmed that the radius of crater estimated by the EFOD was in a good agreement with that obtained by the FE analysis. Furthermore, the experiment using a single particle impact testing system showed that the EFOD can estimate the radius of crater on a SS400, C1020 and A1070 substrates accurately.

  • 松岡 瑛喜, 廣瀬 陽一, 倉橋 貴彦, 村上 祐貴, 外山 茂浩, 池田 富士雄, 井山 徹郎, 井原 郁夫
    2018 年 67 巻 9 号 p. 869-876
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    In this paper, we present the inverse analysis for identification of the cavity position and the cavity size in structures. The performance function is defined by square sum of residual between the observed and the computed sound pressure. Here, the observed sound pressure is measured by the microphone in the experiment of hammering test. The problem is to find the cavity position and the cavity size so as to minimize the performance function. The formulation for this problem is carried out by the adjoint variable method, and the numerical simulation of the sound pressure propagation is carried out based on the wave equation and the finite element method. In addition, the identification of the cavity position and the cavity size is also carried out based on the adjoint variable and the finite element methods. The hammering signal is also identified by the observed sound pressure. To do that, it is important how to give the initial condition of the cavity position and the cavity size. In this study, the result of the clustering based on the self-organizing map is employed to determine the initial condition of the cavity position and the cavity size. The identification of the cavity position and the cavity size for a partial problem is shown in this paper.

  • 佐藤 賢之介, 斎藤 豪, 佐伯 竜彦, 小根澤 英之
    2018 年 67 巻 9 号 p. 877-884
    発行日: 2018/09/15
    公開日: 2018/09/20
    ジャーナル フリー

    This study was conducted to investigate the properties of sulfate ion transfer and the effects of pore structure and surface potential on sulfate ion transfer in cementitious materials after 5mass% sulfate solution immersion. In this study, the sulfate ion effective diffusion coefficient, the oxygen gas diffusion coefficient, the porosity, the pore size distribution and the ion composition of the pore solution of cement paste specimens after 5mass% sodium sulfate and 5mass% magnesium sulfate solution immersion were measured. The tortuosity of sulfate ion diffusion and that of oxygen diffusion were calculated from each diffusion coefficient, and the ratio of two tortuosity which is indirectly expressing the effect of surface potential was calculated. Results shows that the tortuosity of sulfate ion transfer was greater than that of oxygen diffusion in most cases of sodium sulfate immersion. On the other hand, in almost half of magnesium sulfate immersion, the tortuosity of sulfate ion transfer was comparable with that of oxygen diffusion. Furthermore, the sulfate ion effective diffusion coefficients decreased with increasing of the ratios of tortuosity of sulfate ion diffusion and that of oxygen gas diffusion in the case of 5mass% sodium sulfate solution immersion. In the case of 5mass% magnesium sulfate solution immersion, the correlation was low as compared to sodium sulfate immersion. Therefore, it was suggested that the effect of surface potential was dominant in sulfate ion transfer in the case of 5mass% sodium sulfate solution and the effect of pore structure was acting more strongly in the case of 5mass% magnesium sulfate solution.

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