• Title/Summary/Keyword: Cubic measurement

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Effect of Growth Conditions on Crystal Quality of InGaN Epitaxial Layers Grown by RF-MBE (RF-MBE 성장조건에 따른 InGaN 단결정 박막의 결정성 관찰)

  • Na, Hyunseok
    • Journal of the Korean Society for Heat Treatment
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    • v.31 no.5
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    • pp.237-243
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    • 2018
  • In-rich InGaN epilayers were grown on (0001) sapphire substrates by radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE). InGaN epilayers grown at various growth condition were observed by SEM, XRD, and RHEED. When plasma power of nitrogen increased from 290 to 350 W, surface morphology and crystal quality became worse according to more active nitrogen on the surface of InGaN at N-rich growth condition. As In composition was reduced from 89 to 71% by changing the incoming flux of In and Ga, surface morphology and crystal quality became worse. In addition, weak peaks of cubic InGaN phase was observed from InGaN layer with 71% In composition by XRD ${\Phi}$ scan measurement. When growth temperature decreased from 500 to $400^{\circ}C$, RHEED diffraction pattern was changed to be from streaky to spotty which means atomically rough surface, and spotty pattern showed cubic symmetry of InGaN clearly. XRD ${\Phi}$ scan measurement gave clear evidence that more cubic InGaN phase was formed at low growth temperature. All these results indicates that extremely low surface mobility of Ga adatom caused inferior crystal quality and cubic InGaN phase.

Installation Error Calibration by Using Levenberg-Marquardt Method on a Cubic Parallel Manipulator (Levenberg-Marquardt 방법을 이용한 육면형 병렬기구의 설치 오차 보정)

  • 임승룡;임현규;최우천;송재복;홍대희
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.184-191
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    • 2003
  • A parallel manipulator has high stiffness and all the joint errors on the device are not accumulated at the end -effector unlike a serial manipulator. These are the reasons why the parallel manipulator has been widely used in many fields of industry. In the parallel manipulator, it is very important to predict the exact pose of the end-effector when we want to control the end-effector motion. Installation errors have to be determined in order to predict and control the actual position and pose of the end-effector. This paper presents an algorithm to find the whole 36 joint error components with joint clearance errors and measurement errors considered, when a link length measurement sensor is used and data more than 36 times are acquired for 36 different configurations. A simulation test using this algorithm is performed with a Matlab program which uses the Levenberg-Marquardt method that is known to be efficient for non-linear optimization.

Realization for Automatic Stock Cubic Measuring and Distributing Management Embedded System with 3D Ultrasonic Sensing (3D 초음파센싱 자동물류부피측정 및 분류관리 임베디드시스템 구현)

  • Lee, Eun-Eok;Ryu, Kwang-Rryol;Hur, Chang-Wu
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.285-288
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    • 2007
  • A realization for automatic stock cubic measuring and distributing management embedded system with 3 dimensional ultrasonic sensing is presented in this paper. The height and width of cubic are measured by comparing the 3 values from 3 ultrasonic sensors with reference when an object is passing the conveyer and length is calculated by the passing time and velocity, compensate cubic values for error to vary with the environment temperature, and reduce the error by averaging the sensing data not to be right posture of object. The system enables to classify and load a packed stocks at the store and transportation practically based on the rectangular hexahedral objects.

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Zirconia galvani sensor for the measurement of oxygen activity (용존산소활량 측정용 지르코니아 갈바니 센서)

  • Oh, Young-Jei
    • Journal of Sensor Science and Technology
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    • v.18 no.6
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    • pp.441-448
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    • 2009
  • Magnesia partially stabilized zirconia(Mg-PSZ) solid electrolytes for an improvement of thermal shock resistance, which is suitable for the measurement of oxygen activity in a molten steel, were prepared by post-thermal aging treatment. The steelmaking oxygen sensor elements were formed by an injection molding method, sintered at $1650^{\circ}C$, and then thermal aged ranged from 1250 to $1400^{\circ}C$. Sintered density and porosity were decreased as increasing the magnesia content in a zirconia-magnesia solid solution. Fractions of cubic phase to the synthesized Mg-PSZ solid electrolytes were ranged from 13.13 to 79.54.% after post-thermal aging treatment. Very dense microstructure without voids in the grains was obtained by the post-thermal aging process. Fine tetragonal phase crystallites precipitated on the cubic surface during post-thermal aging up to $1300^{\circ}C$ improve a thermal shock resistance and reappearance of electro motive force(EMF) curve.

Investigation of Strain Measurements using Digital Image Correlation with a Finite Element Method

  • Zhao, Jian;Zhao, Dong
    • Journal of the Optical Society of Korea
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    • v.17 no.5
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    • pp.399-404
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    • 2013
  • This article proposes a digital image correlation (DIC) strain measurement method based on a finite element (FE) algorithm. A two-step digital image correlation is presented. In the first step, the gradient-based subpixels technique is used to search the displacements of a region of interest of the specimen, and then the strain fields are obtained by utilizing the finite element method in the second step. Both simulation and experiment processing, including tensile strain deformation, show that the proposed method can achieve nearly the same accuracy as the cubic spline interpolation method in most cases and higher accuracy in some cases, such as the simulations of uniaxial tension with and without noise. The results show that it also has a good noise-robustness. Finally, this method is used in the uniaxial tensile testing for Dahurian Larch wood specimens with or without a hole, and the obtained strain values are close to the results which were obtained from the strain gauge and the cubic spline interpolation method.

A Human Enginnering Study on an Original Pattern of Clothing for an Abnormal Type of Figure - with special reference to the of kyphosis - (이상체형의 의복원형의 인간공학적연구 - 척추만곡체형을 중심으로 -)

  • 박정순
    • Journal of the Korean Home Economics Association
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    • v.20 no.3
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    • pp.9-18
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    • 1982
  • In this study, we attempted to make an original pattern of clothing for an abnormal type of figure, especially for the type of kyphosis. We measured the curvature of the spine of a woman with kyphosis with a Martin measuring instrument and a silhouetter in the following ways. First, we counted the rate of shrinkage of the standard lines drawn on the surface of the body according as the body moved. Secondly, placing the front and back darts, the front and back shoulder darts and the side darts according to“Munhwa”pattern, we made cubic cuttings of four moving postures as well as the standing one. Thirdly, we superposed the developed patterns of the standing and the moving postures, measuring the position change and the amount of the chaange of the darts, and compared them. The results are as follows: 1) In the developed pattern of a cubic cutting of the basic pattern and the standing posture, the neckhole became larger than that of the basic pattern, and the waist line was lowered than that of the basic pattern because the center back line was shortened due to the curved backbone. 2) As for the change of the standard line according to the movement, we found that the waist line, the center front line, the center back line, the bust width line, the upper back width line and the back width line became longer. Special consideration must be given to the function of the clothing for an abnormal type of figure. 3) The difference of the measurements between the cubic cutting and the body measurement regardless of the body movement is due to a gap by an acute angle at the jutted place between the developed pattern and the body surface. We found that the body measurement of the upper back width line, the back width line and the bust line became larger. Consequently, in making an original clothing pattern, it is desirable that we must not place the front and the back waist darts at the jutted place on the back from the functional and the aesthetic viewpoint of clothing. It is also desirable that we must widen the neckhole because the shoulder angle is close to a straight line due to a jut of the upper back width line.

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A STUDY OF HYDRAULIC PROPERTIES IN A SINGLE FRACTURE WITH IN-PLANE HETEROGENEITY: AN EVALUATION USING OPTICAL MEASUREMENTS OF A TRANSPARENT REPLICA

  • Sawada, Atsushi;Sato, Hisashi
    • Nuclear Engineering and Technology
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    • v.42 no.1
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    • pp.9-16
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    • 2010
  • Experimental examinations for evaluating fracutres were conducted by using transparent replicas of a single fracture in order to obtain the fracture data to contribute to the methodlogy on how to improve the definitaion of representative parameter values used for a parallel plate fracture model. Quantitative aperture distribution and quantitative tracer concentration data at each point in time were obtained by measuring the attenuation of transmitted light through the fracture in high spatial resolution. the representative aperture values evaluated from the multiple different measurement methods, such as arithmetic mean of aperture distribution measured by the optical method, transport aperture evaluated from the tracer test, and average aperture evaluated from the fracture void volume measurement converged to a unique value that indicates the accuracy of this experimental study. The aperture data was employed for verifying the numerical simulation under the assuption of Local Cubic Law and showed that the calculated flow rate through the fracture is 10%-100% larger than hydraulic test results. The quantitative tracer concentration data is also very valuable for validating existing numerical code for advection dispersion transport in-plane heterogeneous fractures.

Density Measurement of Liquid Mixture and Estimation of Excess Molar Volume by A Cubic Equation of State (액체혼합물의 밀도 측정과 3차 상태방정식에 의한 과잉 몰부피의 예측)

  • Kim, Jung-Min;Bae, Hyo-Kwang
    • Korean Chemical Engineering Research
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    • v.43 no.5
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    • pp.637-640
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    • 2005
  • The density of polar-nonpolar liquid mixtures composed of methyl tert-butyl ether(MTBE) and 2,2,4-trimethylpentane, and methyl ethyl ketone (MEK) and 2,2,4-trimethylpentane, and the density of polar-polar liquid mixture of MTBE and MEK were measured by densitometer at 278.15 K, 288.15 K and 298.15 K, respectively. The excess molar volume of the binary systems calculated from the measured density was shown good agreement with the calculated one by the cubic Peng-Robinson- Stryjek-Vera (PRSV) equation of state together with Huron-Vidal mixing rule and it confirmed that the cubic PRSV equation of state could be used in the molar volume calculation of polar mixture.

Accurate Prediction of the Pricing of Bond Using Random Number Generation Scheme (난수 생성기법을 이용한 채권 가격의 정확한 예측)

  • Park, Ki-Soeb;Kim, Moon-Seong;Kim, Se-Ki
    • Journal of the Korea Society for Simulation
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    • v.17 no.3
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    • pp.19-26
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    • 2008
  • In this paper, we propose a dynamic prediction algorithm to predict the bond price using actual data set of treasure note (T-Note). The proposed algorithm is based on term structure model of the interest rates, which takes place in various financial modelling, such as the standard Gaussian Wiener process. To obtain cumulative distribution functions (CDFs) of actual data for the interest rate measurement used, we use the natural cubic spline (NCS) method, which is generally used as numerical methods for interpolation. Then we also use the random number generation scheme (RNGS) to calculate the pricing of bond through the obtained CDF. In empirical computer simulations, we show that the lower values of precision in the proposed prediction algorithm corresponds to sharper estimates. It is very reasonable on prediction.

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