• 통합자연과학논문집
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• 제3권3호
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• pp.148-152
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• 2010

Photoluminescence properties and surface morphologies of porous silicon etched with various applied current densities at fixed etching times. FE-SEM image of porous silicon surface indicated that the porous silicon prepared at currents below 200 mA exhibited very bright red photoluminescence properties. As the applied current densities increased, the photoluminescence efficiencies of porous silicon prepared at applied current densities above 300 mA decreased, and displayed the cracked surface on porous silicon. This cracked surface start to collapsed to give cracked domains.

• 전자공학회논문지A
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• 제29A권8호
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• pp.56-62
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• 1992

This paper is analyzed the charge trapping and electrical properties of 0(Oxide), NO(Nitrided oxide) and ONO(Reoxidized nitrided oxide) as dielectric films in MIS structures. We have processed bottom oxide and top oxide by the thermal method, and nitride(Si$_{3}N_{4}$) by the LPCVD(Low Pressure Chemical Vapor Deposition) method on P-type(100) Silicon wafer. We have studied the charge trapping properties of the dielectrics by using a computer controlled DLTS system. All of the dielectric films are shown peak nearly at 300K. Those are bulk traps. Many trap densities which is detected in NO films, but traps. Many trap densities which is detected in NO films. Varing the nitride thickness, the trap densities of thinner nitride is decreased than the thicker nitride. Finally we have found that trap densities of ONO films is affected by nitride thickness.

• ETRI Journal
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• 제17권2호
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• pp.11-19
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• 1995

The plasma densities generated from a semiconductor bridge (SCB) device employing a capacitor discharge firing set have been measured by a novel diagnostic technique employing a microwave resonator probe. The spatial resolution of the probe is comparable to the separation between the two wires of the transmission lines (${\approx}$3 mm). This method is superior to Langmuir probes in this application because Langmuir probe measurements are affected by sheath effects, small bridge area, and unknown fraction of multiple ions. Measured electron densities are related to the land material and input energy. Although electron densities in the plasma generated by aluminum or tungsten-land SCB devices show a general tendency to increase steadily with power, at the higher energies, the electron densities generated from tungsten-land SCB devices are found to remain constant.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.130-133
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• 2011

This paper reports the Survey results from a field monitoring study of office occupancy densities. The field measurement of a office in Yongin was carried out from 19 September to 30 September 2011. The survey has an aim to reveal the building energy consumption relationship between occupancy densities of a realistic office and the previous studies. The results showed that hourly occupied density of the previous studies is more higher than a field survey. we investigated the effects of difference occupancy densities on annual heating and cooling energy consumption using EnergyPlus. Heating and cooling consumption was raised because of the increased occupancy density. therefore, accurately measure the occupnacy schedule is important in order to reduce excessive building energy consumption, and is an significant element to be considered in the energy simulation.

• Communications for Statistical Applications and Methods
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• 제11권3호
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• pp.609-617
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• 2004

To present graph of probability densities, many softwares and graphical tools use methods that link points or straight lines. However, the methods can't display exactly and smoothly the graph and are not efficient from the viewpoint of process time. One method to overcome these shortcomings is utilizing interpolation methods. In these methods, selecting the number and location of knots is an important factor. This article proposes an algorithm to select knots for graphically presenting densities and implements graph components based on the algorithm.

• 한국작물학회지
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• 제33권1호
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• pp.1-4
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• 1988

남부지방에서 황금의 직파재배시 재식밀도가 생육과 품질 및 수량에 미치는 영향을 구명하여 적정 재식거리를 확립하고자 시험한 결과는 다음과 같다. 1. 초장은 밀식일수록 크고, 소식일수록 짧아서 재식주수와 초장은 고도의 정의 상관이 인정되었다. 2. 경직경과 분지수는 소식일수 크고 밀식일수록 적었다. 3. 수량구성요소인 주당 근장과 건근중은 재식주수가 많을수록 감소되어 부의 상관이 인정되었다. 10a당 건근중은 재식주수가 많은 밀식구에서 증가되는 경향이었다. 4. 품질은 밀식에서는 1개 건근중이 가벼워 상품비율이 낮았으나, 소식에서는 1개 건근중이 무거워 상품비율이 높았다. 이상과 같은 결과로 보아 30$\times$10cm(33주/m$^2$)가 상품비율이 높고 1개 건근중도 무거워 알맞은 재식거리로 사료된다.

• 한국도로학회논문집
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• 제17권1호
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• pp.51-58
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• 2015

PURPOSES : The objective of this study is to compare the densities of asphalt pavements measured both in the field and in the laboratory, and also to evaluate the applicability of field density measuring equipment, such as the pavement quality indicator (PQI), by using statistical analysis. METHODS : For the statistical analysis of the density measured from asphalt pavement, student t-tests and a coefficient of correlation are investigated. In order to compare the measured densities, two test sections are prepared, with a base layer and an intermediate layer constructed. Each test section consists of 9 smaller sections. During construction, the field densities are measured for both layers (base and intermediate) in each section. Core samples are extracted from similar regions in each section, and moved to the laboratory for density measurements. All the measured densities from both the field and laboratory observations are analyzed using the selected statistical analysis methods. RESULTS AND CONCLUSION : Based on an analysis of measured densities, analysis using a correlation coefficient is found to be more accurate than analysis using a student t-test. The correlation coefficient (R) between the field density and the core density is found to be very low with a confidence interval less than 0.5. This may be the result of inappropriate calibration of the measuring equipment. Additionally, the correlation coefficient for the base layer is higher than for the intermediate layer. Finally, we observe that prior to using the density measuring equipment in the field, a calibration process should be performed to ensure the reliability of measured field densities.

• Asian-Australasian Journal of Animal Sciences
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• 제13권7호
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• pp.929-934
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• 2000

Optimum stand density of alfalfa (Medicago sativa L.) varies with locations and climates. Stand density is one of the factors that determines herbage yield, forage quality and persistence of alfalfa. As establishment costs increase, the question arises whether present population densities are optimum for obtaining maximum herbage yield and forage quality. The objectives of this study were: 1) to determine the optimum plant density for highest herbage yield and forage quality for the dehydrated alfalfa industry under Edmontons climatic conditions in Alberta, Canada; 2) to compare herbage yield and forage quality of the cultivars 'Algonquin' and 'Vernal' grown at a range of stand densities. Alfalfa seedlings of both cultivars were either transplanted at spacings of 6, 10, 15 and 25 cm or direct seeded at the 4.5 cm plant spacings, providing population densities of 494, 278, 100, 45 and $16plants/m^2$. The experimental design was a randomized complete block with a split-plot arrangement having three replicates; the main plots consisted of two alfalfa cultivars Algonquin and Vernal, and the sub-plots were the five population densities. The cultivar Vernal had significantly higher annual yield than did the cultivar Algonquin. There was no significant effect of plant density on herbage yield. There was no difference in crude protein (CP) between the two cultivars. At the first cut, there was a significant quadratic effect of plant density on CP content and the greatest CP occurred at the 100 plants/m2 density. Crude protein was not affected by plant density at the second cut. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) were not affected by plant density. The cultivar Algonquin usually had a lower ADF and NDF than cultivar Vernal. In conclusion, high population densities ($278plants/m^2$ or more) of alfalfa did not improve herbage yield and forage quality compared with low plant population densities ($100plants/m^2$ or less) of alfalfa.

• 수산해양교육연구
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• 제23권4호
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• pp.772-778
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• 2011

In order to estimate the densities and composition of floating marine debris (FMD), a sighting survey was conducted from July 1st to July 14th, 2009 in the East China Sea (ECS) using a training vessel "Kaya (1,737 ton)" of Pukyong National University. The sampled zones are divided into 5 transects by observation day during the survey days and the densities and composition in each transect were calculated using the numbers of item per $km^2$. The results of distribution of FMD are as follows: 1. During the surveys, a large variety of FMD was discovered and highest densities were found in the Central East(CE) of the East China Sea(ECS) (48.2 items/$km^2$), whereas densities in the less populated transects in Okinawa(OK1, OK2) were comparatively low(3.5 ~ 4.9 items//$km^2$). 2. Among the classified 6 items, styrofoams(Styro) were most abundant and ubiquitous(10.3 items/$km^2$, 53% of the total number), except OK2 area. Next abundant item was vinyl and plastics called V & P(4.9 items/$km^2$, 25%). Above 2 items of the major proportion of FMD accounted for 78% of the total number of FMD observed through this study. 3. The percentages of manufactured plastics(Styro and V & P) found in the Seas near Korean Peninsula were varied from 87.2% to 69.8%. It was recognized that polluted level is middle value among them.

• Communications for Statistical Applications and Methods
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• 제4권2호
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• pp.465-471
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• 1997

This paper deals with the problems of obtaining some Bayesian and empirical Bayesian Predictive densities and prediction intervals of a future observation $X_{(\tau+\gamma)}$ in the Rayleigh distribution. Using an inverse gamma prior distribution, some prodictive densities and prodiction intervals are proposed and studied. Also the behaviors of the proposed results are examined via numerical examples.