• Title/Summary/Keyword: value gap

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Growth and Properties of $Cd_{1-x}$$Zn_x$/S Films Prepared by Chemical Bath Deposition for Photovoltaic Devices (Chemical Bath Depsoition법에 의한 $Cd_{1-x}$$Zn_x$/S 박막의 제조 및 특성에 관한 연구)

  • 송우창;이재형;김정호;박용관;양계준;유영식
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.2
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    • pp.104-110
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    • 2001
  • Structural, optical and electrical properties of Cd$_{1-x}$ Zn$_{x}$S films deposited by chemical bath deposition(CBD), which is a very attractive method for low-cost and large-area solar cells, are presented. Especially, in order to control more effectively the zinc component of the films, zinc acetate, which was used as the zinc source, was added in the reaction solution after preheating the reaction solution and the pH of the reaction solution decreased with increasing the concentration of zinc acetate. The films prepared after preheating and pH control had larger zinc component and higher optical band gap. The crystal structures of Cd$_{1-x}$ Zn$_{x}$S films was a wurtzite type with a preferential orientation of the (002) plane and the lattice constants of the films changed from the value for CdS to those for ZnS with increasing the mole ratio of the zinc acetate. The minimum lattice mismatch between Cd$_{1-x}$ Zn$_{x}$S and CdTe were 2.7% at the mole ratio of (ZnAc$_2$)/(CdAc$_2$+ZnAc$_2$)=0.4. As the more zinc substituted for Cd in the films, the optical transmittance improved, while the absorption edge shifted toward a shorterwavelength. the photoconductivity of the films was higher than the dark conductivity, while the ratio of those increased with increasing the mole ratio of zinc acetate. acetate.

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Structural and Electrical Properties of (Na0.465K0.465Bi0.07)(Nb0.93Ti0.07)O3-0.08MnO2 Ceramics with Variation of Sintering Temperature (소결온도에 따른 (Na0.465K0.465Bi0.07)(Nb0.93Ti0.07)O3-0.08MnO2 세라믹스의 구조적, 전기적 특성)

  • Lee, Tae-Ho;Yeo, Jin-Ho;Lee, Sung-Gap
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.7
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    • pp.506-510
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    • 2012
  • In this study, lead-free $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ ceramics were fabricated by conventional mixed oxide method. Structural and electrical properties of lead-free $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ ceramics with the variation of sintering temperature were investigated. As results of x-ray diffraction analysis, all specimens showed a typical polycrystalline perovskite structure without presence of the second phase. Sintered density increased with an increases of sintering temperature and the specimen sintered at $1,020^{\circ}C$ showed the maximum value of 4.5 $g/cm^3$. The average grain size of the $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ specimen sintered at $1,020^{\circ}C$ is about 0.83 ${\mu}m$. Electromechanical coupling factor, relative dielectric constant and dielectric loss of $(Na_{0.465}K_{0.465}Bi_{0.07})(Nb_{0.93}Ti_{0.07})O_3-0.08MnO_2$ specimens sintered at $1,020^{\circ}C$ were 0.252, 741 and 0.043% respectively.

Secondary mathematics teachers' recognition of the affective domain and analysis od condition in mathematics teaching (중등 수학 교사들의 정의적 특성에 대한 인식과 수업 실태 분석)

  • Han, Hye-Sook;Choi, Kye-Hyen
    • Journal of the Korean School Mathematics Society
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    • v.14 no.4
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    • pp.491-518
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    • 2011
  • According to a number of recent studies, Korean students' affective achievement was at much lower level than cognitive achievement, which indicated the needs for nationwide researches. Although a variety of effort was put into finding ways to improve students' affective achievement, few researches focused on teachers was being underway. Thus, this study was conducted with 327 secondary school mathematics teachers in Gyeonggi-do- by survey method to investigate on how teachers feel affective domain in their teaching practice, how much they it into account at class, and what their wills or plans are to put it into action. According to the results, there existed a distinctive gap between teachers and students in affective domain.

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Properties of Frankfurter-type Sausages with Pork Back-fat Replaced with Bovine Heart Surimi-like Materials

  • Seo, Jin-Kyu;Yum, Hyeon-Woong;Kim, Gap-Don;Jeong, Jin-Yeon;Yang, Han-Sul
    • Food Science of Animal Resources
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    • v.36 no.4
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    • pp.523-530
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    • 2016
  • This study investigates the effect of bovine heart surimi-like material (BHSM) used as a back fat replacer, on the physicochemical and sensory characteristics of frankfurter-type sausages. Frankfurter-type sausage with added BHSM had a higher moisture content and lower fat content than the control. In addition, the samples with added BHSM had higher pH, cooking loss and 2-thiobarbituric acid-reactive substance (TBARS) value and lower water exudation than the control. The sausage formulation with 40% BHSM was more effective in delaying lipid oxidation without affecting cooking loss compared to the 60% BHSM treatment sample. Results showed that hardness values increased upon replacement with BHSM, and sausages manufactured with 40% BHSM had higher lightness and lower redness values. Panelists found there were no differences in color, odor, and tenderness scores and the overall acceptability score found that treatment samples containing 20% and 40% BHSM were preferable to the control after storage for 14 d. These results indicate that fat replacement with BHSM was beneficial to the quality of frankfurter-type sausages, and acceptable reduced-fat products can be produced when back fat is replaced with up to 40% BHSM.

Development of a novel self-centering buckling-restrained brace with BFRP composite tendons

  • Zhou, Z.;He, X.T.;Wu, J.;Wang, C.L.;Meng, S.P.
    • Steel and Composite Structures
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    • v.16 no.5
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    • pp.491-506
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    • 2014
  • Buckling-restrained braces (BRBs) have excellent hysteretic behavior while buckling-restrained braced frames (BRBFs) are susceptible to residual lateral deformations. To address this drawback, a novel self-centering (SC) BRB with Basalt fiber reinforced polymer (BFRP) composite tendons is presented in this work. The configuration and mechanics of proposed BFRP-SC-BRBs are first discussed. Then an 1840-mm-long BFRP-SC-BRB specimen is fabricated and tested to verify its hysteric and self-centering performance. The tested specimen has an expected flag-shaped hysteresis character, showing a distinct self-centering tendency. During the test, the residual deformation of the specimen is only about 0.6 mm. The gap between anchorage plates and welding ends of bracing tubes performs as expected with the maximum opening value 6 mm when brace is in compression. The OpenSEES software is employed to conduct numerical analysis. Experiment results are used to validate the modeling methodology. Then the proposed numerical model is used to evaluate the influence of initial prestress, tendon diameter and core plate thickness on the performance of BFRP-SC-BRBs. Results show that both the increase of initial prestress and tendon diameters can obviously improve the self-centering effect of BFRP-SC-BRBs. With the increase of core plate thickness, the energy dissipation is improved while the residual deformation is generated when the core plate strength exceeds initial prestress force.

A Study on Korean Plastic Characteristics Expressed in Modem Costume - Laying Stress on the Concept of Void, Trait de Korean Painting - (현대 복식에서 표현된 한국적 조형 특성 연구 - 한국 회화의 운필, 여백의 개념을 중심으로 -)

  • Kim, Mi-Gap;Yang, Sook-Hi
    • The Research Journal of the Costume Culture
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    • v.15 no.6
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    • pp.965-981
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    • 2007
  • Since the latter half of 20 century, in Korea, there are many discussions on the identity of Korean itself in several divisions, in which the discussion on the identity in the part of the costume or the part of the art reflecting the life, is the subject which must not fail to be noticed. So, we try to study the common structure manifested in the Korean painting and the costume as a part of basic recognition of problems and the way of problem-solving for the research on the Koran formative characteristics. The method and the process of this study is first, to consider the characteristics of the plastic and style of the Oriental arts and the Occidental arts by discourse implicate the difference between Oriental and Occidental view and the recognition of the body in the two worlds. And in the study we try to apprehend the dynamic modern artistic value of Korean style through assimilation between the Korean style and Baroque style according to the theory of $W\ddot{o}lfflin$ about the classical style and Baroque style. We will describe the Korean identity by analyzing the Korean plasticity with the Occidental style of dress and paintings reflecting the Occidental culture and thought and the Oriental things, and modern paintings and dress in the present age. As a result, we can try to recherche the way of use of new design for the identity of Korean style, in the concept of the ellipsis, repetition of the retrait, obscur silhouette, and superimposition.

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Image Magnification using Fuzzy Method for Ultrasound Image of Abdominal Muscles (복부 초음파 영상에서의 퍼지 기법을 이용한 영상 확대)

  • Kim, Kwang-Baek;Lee, Hae-Jung
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.4
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    • pp.23-28
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    • 2011
  • Ultrasound images for the abdominal muscles are complicated enough to have difficulty in interpreting their results. For better interpretation, magnifying the original image is necessary but its magnified image could be deteriorated and suffer from information loss. Thus, in this paper, we propose a magnifying method that reduces the gap between the original image and the magnified one in quality using a fuzzy method with weights for its brightness and interpolation. The proposed method extracts information of pixels in magnified image that have most similar characteristics of the original one by applying fuzzy membership function. In the process, the difference in the brightness between pixels of the magnified image and the original one using bilinear interpolation method and the weight value using the interpolation from multiplied values of four pixels are supplied to the fuzzy membership function. In this experiment, the proposed method reduces the cloudy phenomenon appears commonly compared to the bilinear interpolation method among those qualitative issues of image interpretation.

DNA barcoding of Schisandraceae in Korea (한국산 오미자과의 DNA 바코드)

  • Youm, Jung Won;Han, Sang-Wook;Seo, Seon Won;Lim, Chae Un;Oh, Sang-Hun
    • Korean Journal of Plant Taxonomy
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    • v.46 no.3
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    • pp.273-282
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    • 2016
  • The establishment of a DNA barcode database at the regional scale and assessments of the utility of DNA barcodes are crucial for conservation biology and for the sustainable utilization of biological resources. Schisandraceae is a small family consisting of ca. 45 species. It contains many economically important species, such as Schisandra chinensis, which is widely used as a source in tonic beverages and in oriental medicine. In Korea, three species, S. chinensis, S. repanda, and Kadsura japonica, are distributed. We evaluated the level of variation of the DNA sequences of rbcL, matK, and the ITS regions from 13 accessions representing the distributional range of the three species. The three DNA barcode regions were easily amplified and sequenced. The minimum values of the interspecific genetic distances among S. chinensis, S. repanda, and K. japonica either separately or in combination are 4- to 23-fold higher than the maximum value of the intraspecific distance, showing that there is a clear DNA barcoding gap in the regions for Korean Schisandraceae. Phylogenetic analyses of the three DNA barcode regions, separately and simultaneously, indicate that all of the DNA barcode regions are useful for identifying a species of Schisandraceae in Korea. The distinctiveness of the three species of Schisandraceae was also supported at the species level when Chinese and Japanese populations were added. The results of this study indicate that three concatenated regions constitute the best option for DNA barcoding in Schisandraceae in Korea.

Statistical Difference of Production Efficiency in Medicinal Crop Farm (약용작물 재배농가의 생산효율성 통계적 차이에 대한 연구)

  • Choi, Don Woo;Kim, Dong Choon;Lee, Hang Ah;Lim, Cheong Ryong
    • Journal of Korean Society for Quality Management
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    • v.48 no.3
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    • pp.453-462
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    • 2020
  • Purpose::This study aims to analyze the management performance and production efficiency of medicinal crop farmers. Methods: We conducted an empirical survey of medicinal crop farmers and analyzed production efficiency using DEA method. Results: First, The crops that increased the number of farms during 2010 and 2018 were Angelica tenuissima and Salvia miltiorrhiza, which was attributed to higher income per hour than other crops. Second, As for the efficiency of Liriope platyphylla, the average was 0.376, and the coefficient of variation was the lowest, 0.566. Third, Salvia miltiorrhiza and Atractylodes japonica had the highest technical efficiency after Liriope platyphylla, but the variation coefficient was high and the efficiency was relatively high. Fourth, As a result of performing variance analysis to find out the difference of each crops on the value of medicinal crop efficiency, the technical efficiency, pure technical efficiency, and scale efficiency were all statistically significant. Conclusion: Based on the results above, following policy suggestions are offered. First, It is necessary to provide information on crops with high income compared to the input of labor, and to develop labor-saving cultivation technologies for each crop. Second, A stable labor supply system will be needed in rural areas. Third, Efforts should be made to close the technological gap between farmers through a lot of education and consulting for farmers who grow medicinal crops.

Monte Carlo Simulation for absorbed dose in PMMA phantom during the low-energy X-ray irradiation (저 에너지 X선 조사 시 PMMA 팬텀 내의 흡수선량 평가를 위한 몬테카를로 시뮬레이션)

  • Kim, Sang-Tae;Kang, Sang-Koo;Kim, Chong-Yeal
    • Journal of the Korean Society of Radiology
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    • v.5 no.6
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    • pp.383-389
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    • 2011
  • This study offered a new method to calculate absorbed dose of actual patients through Monte Carlo Simulation by using the linkage of Geant4 and DICOM, and, the experimental value of absorbed dose at the center and Geant 4 simulation result according to the depth of PMMA mock phantom were compared by using MOSEF in order to verify Geant4 calculation code. In the area where there was no air space between the irregular gap due to incomplete compression of PMMA slab, the differences were $0.46{\pm}4.69$ percent and $-0.75{\pm}5.19$percent in $15{\times}15cm^2$ and $20{\times}20cm^2$ respectively. Excluding the error due to incomplete compression of PMMA mock phantom, the calculation values of the Monte Carlo simulation by linkage of Geant4 and DICOM was the same.