• 제목/요약/키워드: Z-factor

검색결과 608건 처리시간 0.02초

몬테 카를로 시뮬레이션을 이용한 2차원 X-선 검출기에 대한 연구 (A Study of 2-dimensional X-ray Detector using Monte Carlo Simulation)

  • 신형섭;이학재;이기성;강정원
    • 반도체디스플레이기술학회지
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    • 제9권4호
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    • pp.67-70
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    • 2010
  • X-ray absorption rate and multiplication factor of X-ray detector were calculated with Garfield code. High Z (= atomic number) was important factor to increase the absorption rate but low Z is also important to increase the multiplication. Five different gas composition were examined under the condition of 1400 V bias and 400 um gap. Xe 100% gas showed the highest absorption rate and He 96% + isobutene 4% showed the highest multiplication.

Kinetic Study of Thermolysin-Catalyzed Synthesis of N-(Benzyloxycarbonyl)-L-Phenylalanyl-L-Leucine Ethyl Ester in an Ethyl Acetate Saturated Aqueous System

  • Nam, Kwang-Ho;Lee, Chang-Kyung;Jeong, Seung-Weon;Chi, Young-Min
    • Journal of Microbiology and Biotechnology
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    • 제11권4호
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    • pp.649-655
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    • 2001
  • The kinetics of the thermolysin-catalyzed synthesis of N-(benzyloxycarbonyl)-L-phenylalanyl-L-leucine ethyl ester (Z-Phe-LeuOEt) from N-(benzyloxycarbonyl)-L-phyenylalanine (Z-Phe) and L-leucine ethyl ester (LeuOEt) in an ethyl acetate saturated aqueous system in a batch operation were studied. The kinetics for the synthesis of Z-Phe-LeuOEt were expressed using a rate equation for the rapid equilibrium random bireactant mechanism. The four kinetic constants involved in the rate equation were determined numerically by the quasi-Newton method so as to fit the calculated results with the experimental data. Within the pH and temperature range examined, the $K_{cat}$ value for the synthesis of Z-Phe-LeuOEt reached a maximum at pH 7.0 and $45^{\circ}C$, whereas the affinity between Z-Phe and thermolysin reached a maximum at pH 6.0 adn $40^{\circ}C$. The inhibitory effect of Z-Phe on the condensation reaction decreased as the pH and temperature decreased. In contrast, they affinity between LeuOEt and thermolysin remained unchanged within the pH and temperature range examined. Therefore, it was concluded that the protonation state of the carboxyl groups. of Z-Phe was more imprtant than that of the amono groups of LeuOEt for the synthesis of Z-Phe-LeuOEt in the present solvent system. The equilibrium yield at pH 6.0 and $30^{\circ}C$ was 8% higher than that at pH 7.0 and $40^{\circ}C$, although the rate was much slower. This result suggested that the affinity between the enzyme and the substrate rather than the overall rate was a more important factor affecting the equilibrium yield, when the peptide synthesis was carried out in a product-precipitation system.

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New ecological health assessment approaches of an urban stream using molecular and physiological level biomarkers and bioindicators

  • Kim, Ja-Hyun;Yeom, Dong-Hyuk;Kim, Joon-Ha;An, Kwang-Guk
    • Animal cells and systems
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    • 제16권4호
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    • pp.329-336
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    • 2012
  • This study evaluated ecological health, using various biomarkers and bioindicators, of pale chub (Zacco platypus) as a sentinel species, in Daejeon Stream, South Korea, during AprilMay 2011. The biomarkers and bioindicators were compared among three sites of control: Reference ($C_z$), transition ($T_z$), and the urban zones ($U_z$); and the 7-Ethoxyresorufin-O-deethylase (EROD) activity, DNA damage, acetylcholinesterase (AChE) activity, and vitellogenin (VTG) concentrations were more significantly increased in the $U_z$ than in the $C_z$. Also, physiological markers such as condition factor, liver somatic index, visceral somatic index, and gonad somatic index were significantly increased in the $U_z$ than in the $C_z$. For the health assessments, three categorized parameters of blood chemistry, molecular biomarkers, and physiological bioindicators were standardized and calculated as a star-plot, representing values of Integrated Health Response (IHR). Values of IHR had more significant (P<0.05) increases in the $U_z$ than any other zones, indicating an impairment of ecological health by organic matter, nutrients (N, P), and toxic chemicals. This study is based on low levels of biological organization approach of molecular and physiological biomarkers and bioindicators, so further study of high-levels of biological organization approach such as community and population is required for overall range of health assessments. The approach of IHR values, however, may be useful in providing early warning of future impacts on ecological health.

다구찌 방법을 이용한 시로코 홴의 최적설계에 관한 실험적 연구 (An Experimental Study on the Optimum Design of Sirocco Fan by Using Taguchi Method)

  • 김장권
    • 대한기계학회논문집B
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    • 제23권6호
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    • pp.761-768
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    • 1999
  • This paper is studied to find the optimum condition of double-inlet Sirocco fan installed in an indoor PAC for low noise operation by the Taguchi method. The goal of this study is to obtain the best combination of each control factor which results in a desired flowrate of Sirocco fan with minimum variability. In this study, the parameter design of the Taguchi method is adopted for robust design by the dynamic characteristic analysis using orthogonal arrays and S/N ratios. The flowrate measurements are conducted by using a multiple-nozzle-type fan tester according to the orthogonal array L9($3^4$). The results of this study can be summarized as follows ; (i) The optimum condition of control factor is a set of where A is an inner to outer diameter ratio($D_1/D_2$), B is a width to outer diameter ratio($L/D_2$), C is a blade attachment angle(${\theta}$) and D is a number of blade(Z), (ii) The flowrate under the optimum condition satisfies the equation $y=0.0384{\cdot}M$ where M is a signal factor, namely number of revolution. The flowrate performance improves about 7.3% more largely as compared with the current condition, which results in about 35RPM reduction of number of revolution for the target flowrate $18.5m^3/min$, and (iii) The sensitivity analysis shows that the major factors in contribution to flowrate performance are A, B, and D ; the percentage contributions of each control factor are 44.01%(Z), 26.77%($D_1/D_2$) and 20.42%($L/D_2$).

횡성호 일대에 분포하는 피라미(Zacco platypus) 개체군의 생태적 특성 분석 (Spatial Analysis of Ecological Characteristics of Zacco platypus Population in Lake Hoengseong Region)

  • 이황구;신현선;김성원;최준길
    • 한국환경생태학회지
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    • 제26권3호
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    • pp.374-381
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    • 2012
  • 본 연구는 횡성호 및 횡성호 상 하류지역을 대상으로 2010년 4월부터 2010년 11월까지 총 4회에 걸쳐 피라미(Zacco platypus) 개체군의 생태적 특성을 조사하였다. 피라미 개체군의 지역별 동태를 비교한 결과 상류지역에서 1,707개체(78.70%)로 가장 큰 개체군을 유지하고 있는 것으로 나타났다. 피라미 개체군의 전장-체중 상관도 분석 결과 횡성호 일대에 분포하는 피라미 개체군의 회귀계수 b값은 3.28로 비교적 안정적인 서식을 하고 있는 것으로 나타났으며, 지역별로는 상류지역 3.28, 횡성호 3.10, 하류지역 3.09로 상류지역에서 가장 양호한 생육상태를 나타내고 있었다. 비만도 지수는 slope가 0.003으로 안정적인 개체군을 형성하고 있는 것으로 나타났으며, 상류지역 0.003, 횡성호와 하류지역이 0.001로 상류지역에서 가장 양호한 영양상태를 유지하고 있었다. 피라미 개체군을 대상으로 전장크기를 비교한 전장빈도 분포 결과 상류지역은 30~50mm, 70~90mm 사이의 개체가 상대적으로 많이 나타났으며, 횡성호에서는 60~80mm의 개체, 횡성호 하류지역은 70~100mm의 개체가 비교적 풍부하게 분포하는 것으로 조사되었다. 결과적으로 횡성호 일대 피라미 개체군은 상류지역에서 가장 안정된 생육상태를 나타냈으며, 서식조건이 충족될 경우 유수역 및 정수역 모두를 선호하는 것으로 확인되었다.

가평천의 물리적 환경요인과 어류 군집구조 분석 (Analysis of Physical Environmental Factors and the Structure of Fish Community in the Gapyeong Stream)

  • 공동수;손세환;김진영;김아름;권용주;김정우;김예지;민정기;김필재
    • 한국물환경학회지
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    • 제33권5호
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    • pp.587-599
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    • 2017
  • Physical environmental factors (water depth, current velocity and substrate) and fish community were surveyed in the Gapyeong stream, Korea. The fish group of Gapyeong Stream was divided into three types. Lithophilic fish, Koreocobitis rotundicaudata and Pseudopungtungia tenuicorpa preferred shallow depth, low-velocity current, and coarse bed condition, whereas Coreoleuciscus splendidus and Microphysogobio longidorsalis were adapted to high-velocity current and bed materials. Nektonic fish, Zacco koreanus and Zacco platypus appeared in a wide range of physical conditions. Intermediate fish, Hemibarbus longirostris, Pungtungia herzi and Coreoperca herzi adapted to moderate water depths and current velocities. Among them, H. longirostris and C. herzi were adapt to various bed materials. C. splendidus, M. longidorsalis and P. herzi showed high niche overlap for current velocity, water depth and substrate with Z. koreanus and Z. platypus. The occurrence of M. longidorsalis in a relatively low-velocity current compared to Z. koreanus and Z. platypus suggests that the current velocity act as a isolation factor for these species. The competition, isolation and character displacement among these species investigated detail in the future. Based on canonical correspondence analysis, the relative importance of each environmental factor was determined as substrate > water depth > current velocity.

듀티 비에 따른 단상 Z-소스 인버터의 효율과 출력 전압에 관한 연구 (A Study on the Output Voltage and Efficiency of the Single-Phase Z-Source Inverters According to Duty Ratio)

  • 홍승표;정영국;임영철
    • 조명전기설비학회논문지
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    • 제25권8호
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    • pp.8-19
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    • 2011
  • This paper was compared for the output voltage and efficiency of the single-phase Z-source inverter(ZSI) according to shoot through duty ratio D. The eight single-phase ZSI in this study are typical ZSI, Embedded ZSI(EZSI), Improved ZSI(IZSI), Quasi ZSI(QZSI), Series ZSI, Trans ZSI(TSI), Switched inductor ZSI(SL-ZSI) and Extended boost ZSI (exZSI). The eight ZSI are divided into two Groups. ; Group-1 which is ZSI with the ordinary voltage boost factor B, and Group-2 which is ZSI with the maximum voltage boost factor B. For the execution of the proposed study, the PSIM simulation was achieved under the condition of input DC voltage=150[V] of ZSI, load =30[${\Omega}$] and 60[Hz] output filter. The output voltage and efficiency of each ZSI were calculated within the limits of D=0.1~0.4. As a result, the output peak voltage of Group-2 was suddenly increased in a specified duty ratio D, and its efficiency was rapidly decreased. On the contrary, Group-1 shown the output and efficiency characteristics without sudden change compared to Group-2 despite the duty ratio increase. The efficiency of the Group-2 was sharply declined at duty ratio D of the most output voltage, but, in case of Group-1, the efficiency was slightly declined. Finally, the input DC current of ZSI with DCM and CCM was discussed.

Theoretical Calculation and Experimental Verification of the Hf/Al Concentration Ratio in Nano-mixed $Hf_xAl_yO_z$ Films Prepared by Atomic Layer Deposition

  • Kil, Deok-Sin;Yeom, Seung-Jin;Hong, Kwon;Roh, Jae-Sung;Sohn, Hyun-Cheol;Kim, Jin-Woong;Park, Sung-Wook
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제5권2호
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    • pp.120-126
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    • 2005
  • We have proposed a characteristic method to estimate real composition when multi component oxide films are deposited by ALD. Final atomic concentration ratio was theoretically calculated from the film densities and growth rates for $HfO_2$ and $Al_2O_3$ using ALD processed HfxAhOz mms.W e have transformed initial source feeding ratio during deposition to fins] atomic ratio in $Hf_xAl_yO_z$ films through thickness factors ($R_{HFO_2}$ ami $R_{Al_2O_3}$) ami concentration factor(C) defined in our experiments. Initial source feeding ratio could be transformed into the thickness ratio by each thickness factor. Final atomic ratio was calculated from thickness ratio by concentration factor. It has been successfully confirmed that the predicted atomic ratio was in good agreement with the actual measured value by ICP-MS analysis.

리트벨트 해석법을 이용한 $Y_1Ba_2Cu_3O_x$ 고온 초전도체의 구조분석 (The structure analysis of $Y_1Ba_2Cu_3O_x$ high Tc superconductor based on rietveld method)

  • 채기병;소대화
    • E2M - 전기 전자와 첨단 소재
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    • 제8권6호
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    • pp.780-786
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    • 1995
  • For the execution of RIETAN program adopting Rietveld Analysis Method, the sample superconductor is made according to the solid state synthesis method at 920.deg. C for 24hrs, and was examined for the optimization of parameters needed to analyze Rietveld method with the input of the measured pattern data after measuring the pattern resulted from the X-ray diffraction. It was proven that the lattice constant of the superconductor which was consisted of Pmmm orthorhombic crystal structure in the analyzed space group correspond to the presented theoretical lattice constant a=3.8887(8).angs., b=3.8238(4).angs., c=11.7079.angs.. Therefore, it was examined and confin-ned that the R factor, which was compensated after analyzing the structure of superconductor resulted from this experimented data with the computer simulation, was refined to $R_{wp}$=8.83[%], $R_{P}$=6.47[%], $R_{I}$=10.08[%], $R_{F}$=7.19[%], $R_{E}$=3.76[%]. On the basis of these experimental data, the significant parameter such as the scale factor(S) and the zero point shift(Z) and FWHM value(U,V,W) were optimized as follows; S=2.0827E-3, Z=0.2146, U=4.2761E-2, V=1.7983E-2, and W=2.6768E-2.2.2.2.2.2.

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Geospatial analysis of wind velocity to determine wind loading on transmission tower

  • Hamzah, Nur H.;Usman, Fathoni
    • Wind and Structures
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    • 제28권6호
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    • pp.381-388
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    • 2019
  • This paper described the application of Geospatial Analysis in determining mean wind speed, $V_h$ for wind load calculation imposed to electrical transmission tower structural design. The basic wind speed data on available station obtained from Malaysian Meteorology Department is adjusted by considering terrain and ground roughness factor. The correlation between basic wind speed, terrain factor and ground roughness stated in EN-50341-1 is used to obtain the $V_h$ for overhead transmission line elements 50 m above ground. Terrain factor, $k_r$ and ground roughness, $z_0$ in this study are presented by land use types of study area. Wind load is then calculated by using equation stated in design code EN-50341-1 by using the adjusted mean wind speed. Scatter plots of $V_h$ for different $k_r$and $z_0$ are presented in this paper to see the effect of these parameters to the value of $V_h$. Geospatial analysis is used to represent the model of $V_h$. This model can be used to determine possible area that will subject to wind load which severe to the stability of transmission tower and transmission line.