Sb 核構造 決定

邊大鉉 弘益大學校 1976 弘大論叢 Vol.8 No.-

The radiation of ??Sb has been studied with a double focusing beta-ray spectrometer which has a resolving power of 0.68 percent for internal conversion electroon energy of 624.1keV emitted from standard source, ??Cs. Beta-spectra measured by this spectrometer, have shown that ??Sb has the end point energyes at 95.37keV, 125.18keV, 132.35keV, 242.12keV, 303.37keV, 323.10keV, 446.23keV and 621.20keV. Twenty-one gamma-rays with energies of 671.40keV, 635.90keV, 606.09keV, 598.92keV, 463.40keV, 443.67keV, 427.90keV, 408.17keV, 379.08keV, 321.05keV, 227.73keV, 208.00keV, 204.11keV, 197.92keV, 178.19keV, 174.97keV, 171.02keV, 116.9keV, 110.07keV, 109.77keV and 35.50 keV were detected by Ge(Li) detector and by a Multichannel analyzer which have 4096 channels. By comparing the data for the beta-ray energies(spin and parity) with those for the gamma-ray energy and degree for multipole emitted from ??Te, the nuclear structure of the ??Te, war determined

Prediction of global geographic distribution of Metcalfa pruinosa using CLIMEX

변대현,정재민,정성훈,이왕희 한국곤충학회 2018 Entomological Research Vol.48 No.2

Globalization has changed the habitats of various species, resulting in harmful pest invasion. Among these pests, Metcalfa pruinosa has caused worldwide economic and hygienic damage in both urban and agricultural/forested areas. It has been reported that prediction of pest distribution is key to the management of pest prevention. Hence, this study aimed to predict the potential geographic distribution of M. pruinosa under the current climate and under a climate change scenario. CLIMEX, modeling software that analyzes the habitat suitability of a target species based on comprehensive climatic and physiological data, was used mainly to establish a map of predictive distribution of M. pruinosa at present and in the future. Based on our simulations, we predict that M. pruinosa will tend to extend its distribution northward in North America and Europe. We conclude that climate change could result in M. pruinosa invasion in a northward direction, suggesting the need for a thorough system of control and prevention.

¹³¹I의 崩壞에 關한 硏究

邊大鉉 弘益大學校 1978 弘大論叢 Vol.10 No.-

The radiation of ??I has been studied with a double focusing beta-ray spectrometer which has a resolving power of 0.68% for internal conversion electron energy of 624.1keV emitted from standard source, ??Cs. Beta-spectra measured by this spectrometer, have shown that ??I has the end point energies at 807.2keV. 605.3keV, 464.6keV, 338.1keV and 247.9keV. These Values of comparative half-lives associated with their maximum end point energies are 9.1, 6.7, 8.05, 6.75 and 6.7 respectively. Six gamma-rays with energies of 721.9keV, 637.1keV, 363.9keV, 285.0keV and 80.0keV were detected by NaI(Ti) scintillator which has a resolving power of 8% for gamma-ray emergy of 661.6keV emitted from standard source, ???Cs, and by a multichannel analyzer which have 512 channels. K to L+M ratios of gamma-rays from ???I are 3.1, 6.0, 8.2, 3.7, 2.2 and 7.2 respectively. The possible transion form associated with K-conversion coefficients are MI transition for two gamma-ray energies of 721.9keV and 80.0keV, M1 and E2 for three gamm-ray energies of 637.1keV, 363.9keV and 285.0.

표면 여기현상을 이용한 내연기관의 열효율 증진에 관한 연구

변대현 弘益大學校 1980 弘大論叢 Vol.12 No.-

The formation of ions in Nacl vapour and charge exchange cross sections of Cd metastable state emitted from a Pt nozzle due to surface excitation phenomena have been studied in this study. And burning temperature of oil burner with changing nozzle material has been also studied. The effects of illuminating the Nacl vapour as it left the heated Pt nozzie, was an increase of about 30% in the ion current. The charge transfer cross sections for the metastable state was larger than for the ground state by a factor 15. The burning temperature has been found to increase with work function of the nozzle material, which is good agreement with the theory of Saha-Langmuir.

β-r 角相關에 關한 硏究

邊大鉉 弘益大學校 1977 弘大論叢 Vol.9 No.-

Non-unique first-forbidden beta ray of end point energy 960keV and 412keV cascade gamma ray of Au?? has been studied as function of energy of beta-particles by means of the Yonsei Ⅱ doublefocusing beta ray spectrometer operated in coincidence with gamma ray detector (Na I (Tl) cryscal). It has been ivestigated that shape factor is small and transition of beta-decay in Au?? nearly displays the statistical shape. The directional correlation for the 2?(β)2?(?)0? cascade of 960keV beta energy has been measured at the energy from 1.41to 2.76 in the relativistic unit. The data for 2?→2? transition are analysed on the basis of the εapproximation and the modified Bij approximation which defines parameter V and Y corresponding to the relative contribution of tensor rank 0 and 1 respectively. On the basic of the modified Bij approximation the shape measurement provides the limit V?+Y?≤0.51, whereas the angular correlation measurement (V+0.893)?+(Y-4.0980)?=(.014±0.05)?.

Vicinal 표면에서의 원자 성장구조연구

邊大鉉 弘益大學校 科學技術硏究所 1999 科學技術硏究論文集 Vol.10 No.1

The stability conditions of ultra thin film growth on vicinal surface are studied through kinetic Monte Ccarlo simulation(KMC). It is seen that the meandering along the step line appeared at high coverage, and these are originated from the diffusion limited aggregation(DLA) of adsorbed atoms. The meandering width depend largely on the magnitude of step detachment diffusion barrier, and have nearly same size as branch width of growth on fcc(100) surface. The stable growth on vicinal surface can be possible only in the condition of low diffusion barrier or low Schwoebel barrier, which are same in the case of growth on fcc(100) surface.

CCD Camera를 이용한 RHEED Oscillation 측정장치 개발

邊大鉉 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.4 No.-

By employing CCD(Charge Coupled Device) camera and image processing software. RHEED spot intensity oscillation could be measured conveniently in real time. The growth rate of homoepitaxial GaAS overlayer was mornitored and analized quntitatively by that system. Further, a method to control the growth rate of thin films by applying the system is suggested.

표면분석을 위한 낮은 에너지 이온용 에너지 분석기의 제작과 특성

邊大鉉 弘益大學校 1984 弘大論叢 Vol.16 No.2

Semi-spherical, cylindrical and retarding potential grid energy analysers are designed and constructed in order to study the characteristics of these analysers. The theoretical and experimental values of V??/V?? for these analysers are measured and compared with others. The experimental value of V??/V?? for semi-spherical analyser is found to be 1.90, which is in good agreement with theoretical value, 1.84, and the resolution is found to be 0.032. The values of experimental and the theoretical of V??/V??, and the resolution for the cylindrical analyser are 1.00, 1.38, and 0.1 respectively. The resolution of retarding potential difference analyser found to be 0.43. The maximum acceptance-angle; tan αis found to be 0.07 from the computer simulation results.

Effect of types of meteorological data on species distribution predicted by the CLIMEX model using an example of Lycorma delicatula (Hemiptera: Fulgoridae)

변대현,정재민,정성훈,이왕희 국립중앙과학관 2020 Journal of Asia-Pacific Biodiversity Vol.13 No.1

Climate has been used as a main variable in species distribution model, suggesting that the type ofmeteorological data can affect the predictive range of a target species. This study was to investigate theeffect of meteorological data on the prediction of the potential distribution of a species in the CLIMEXmodel.We constructed three different types of meteorological data to be inserted into the CLIMEX modelto predict the climatic suitability of the spotted lanternfly [Lycorma delicatula (Hemiptera: Fulgoridae)] inSouth Korea: (1) minimumemaximum data (Y-data), (2) annual average data (AY-data), and (3) 30-yearlong-term average data (A-data). As a result, the climatic suitability represented by the Ecoclimatic Index(EI) was significantly different in the Y-data compared with the other data sets because of the extremewinter condition in which they were recorded. In contrast, the AY- and A-data sets showed similar climaticsuitability, but the AY-data showed slightly higher Ecoclimatic Index values than the A-data. It isconclusive that the AY- and A-data sets were suitable for evaluating annual variations by the years of datacollection and current potential distribution, respectively, whereas the Y-data could be used for simulationunder extreme climate conditions for a conservative assessment.

Effectiveness of Sensitivity Analysis for Parameter Selection in CLIMEX Modeling of Metcalfa pruinosa Distribution

변대현,정성훈,모창연,이왕희 한국농업기계학회 2018 바이오시스템공학 Vol.43 No.4

Purpose: CLIMEX, a species distribution modeling tool, includes various types of parameters representing climatic conditions; the estimation of these parameters directly determines the model accuracy. In this study, we investigated the sensitivity of parameters for the climatic suitability calculated by CLIMEX for Metcalfa pruinosa in South Korea. Methods: We first changed 12 parameters and identified the three significant parameters that considerably affected the CLIMEX simulation response. Results: The result indicated that the simulation was highly sensitive to changes in lower optimal temperatures, lower soil moisture thresholds, and cold stress accumulation rate based on the sensitivity index, suggesting that these were the fundamental parameters to be used for fitting the simulation into the actual distribution. Conclusion: Sensitivity analysis is effective for estimating parameter values, and selecting the most important parameters for improving model accuracy.