• Nuclear Engineering and Technology
• /
• 제56권4호
• /
• pp.1165-1203
• /
• 2024

In the paper we validate theoretical models of the pulse against experimental data from the Jozef Stefan Institute TRIGA Mark II research reactor. Data from all pulse experiments since 1991 have been collected, analysed and are publicly available. This paper summarizes the validation study, which is focused on the comparison between experimental values, theoretical predictions (Fuchs-Hansen and Nordheim-Fuchs models) and calculation using computational program Improved Pulse Model. The results show that the theoretical models predicts higher maximum power but lower total released energy, full width at half maximum and the time when the maximum power is reached is shorter, compared to Improved Pulse Model. We evaluate the uncertainties in pulse physical parameters (maximum power, total released energy and full width at half maximum) due to uncertainties in reactor physical parameters (inserted reactivity, delayed neutron fraction, prompt neutron lifetime and effective temperature reactivity coefficient of fuel). It is found that taking into account overestimated correlation of reactor physical parameters does not significantly affect the estimated uncertainties of pulse physical parameters. The relative uncertainties of pulse physical parameters decrease with increasing inserted reactivity. If all reactor physical parameters feature an uncorrelated uncertainty of 10 % the estimated total uncertainty in peak pulse power at 3 $ inserted reactivity is 59 %, where significant contributions come from uncertainties in prompt neutron lifetime and effective temperature reactivity coefficient of fuel. In addition we analyse contribution of two physical mechanisms (Doppler broadening of resonances and neutron spectrum shift) that contribute to the temperature reactivity coefficient of fuel. The Doppler effect contributes around 30 %-15 % while the rest is due to the thermal spectrum hardening for a temperature range between 300 K and 800 K.

• 한국생활과학회지
• /
• 제9권4호
• /
• pp.471-482
• /
• 2000

The purpose of this study is to produce slacks pattern for pregnant women in the mid or second half period of their pregnancy according to the development figure of the body shell from a follow-up measurement. We here would like to produce slacks pattern for pregnant women constructed to fit better with their individual property in their figure and to help maintain the shape and beauty of the lower half of body and would compare it with two manufactured slacks pattern. The results of the study were as follows; 1. As the pregnancy proceeds, the height of natural-waist line went up spontaneously due to the projection of abdominal region, therefore, it was given darts at the front zipper part so that they could maintain a nice figure and to avoid possibility of feeling oppressed. To acquire a slimmer outfit, we made of the slacks-bottom narrower than the width at the knee line, and it worked out. 2. Sensory evaluation for appearance: According to the statistical of the result of 19items on the questionaire, all items showed significant difference(a$\leq$0.01) between the new and A(bunka) B(Kim's pattern) method slacks pattern, with the new pattern having higher scores. The new drafting method proved to be better fitted, to fit the shape of bodies properly and to get a visual effect to look slim.

• 전력전자학회논문지
• /
• 제16권3호
• /
• pp.293-301
• /
• 2011

본 논문에서는 정류용 브릿지 다이오드가 없는 고효율 하프 브릿지 AC-DC 컨버터를 제안한다. 제안하는 컨버터는 비대칭 펄스 폭 변조 방식의 하프 브릿지 DC-DC 컨버터와 정류용 브릿지 다이오드가 없는 역률 개선 회로가 통합된 회로 구조를 지닌다. 제안하는 컨버터는 정류용 브릿지 다이오드를 사용하지 않고 교류 입력 전압으로부터 절연된 직류 출력 전압을 공급한다. 간단한 회로 구조와 함께 도통 손실을 줄일 수 있다. 또한 스위칭 소자들의 영전압 스위칭을 통하여 스위칭 손실을 줄일 수 있다. 두 개의 직렬 연결된 트랜스포머를 구비함으로서 프로파일을 낮추고 전력밀도를 높일 수 있다. 250 W (48 V / 5.2 A) 회로 설계 및 실험을 통하여 제안된 컨버터의 성능을 $90 \;V_{rms}$ 교류 입력 전압에 대하여 입증하였다.

• 한국전기전자재료학회논문지
• /
• 제36권2호
• /
• pp.136-142
• /
• 2023

In the past, the efficiency of solar cells had been increased in order to increase the efficiency of solar modules. However, in recent years, in order to increase output in the solar industry and market, the competitiveness of solar cells based on large-area solar cells and multi-bus bar has been increasing. Multi-busbar solar module is a technology to reduce power loss by increasing the number and width of the front busbar of the solar cell and reducing the current value delivered by the busbar by half through half-cutting. In the case of the existing M2 (156.75×156.75 mm²) solar cell, even with a half-cut, power loss could be sufficiently reduced, but as the area of the solar cell is enlarged to more than M6 (166×166 mm²), the need for more divisions emerged. This affected not only solar cells but also inverters required for module array configuration. Therefore, in this study, the electrical characteristics of a large-area solar cell and after division were extracted using Griddler simulation. The output characteristics of the module were predicted by applying the solar cell parameters after division to PSPice, and a guideline for the large-area solar module design was presented according to the number of divisions of the large-area solar cell.

• 복식문화연구
• /
• 제26권1호
• /
• pp.30-44
• /
• 2018

The study purpose was to investigate the jacket-fit satisfaction level of men in their 20s and 30s, using body-scanning data and a questionnaire. Thirty-five men were scanned using a 3D body scanner. The participants were divided into three groups (Small, Medium, and Large) based on their chest-circumference measurement. Their levels of satisfaction with the fit of their tailored jacket were compared by group. Chest, waist, and hip circumferences increased substantially as group size increased. The M-group was mostly satisfied with all body-site views. The S-group was especially dissatisfied with height, back width, waist circumference, and upper-arm circumference. The L-group was especially dissatisfied with waist circumference and hip circumference. The majority of the participants preferred the jacket closely fitted to their body. More than half of the participants thought finding a jacket of suitable size was difficult. When purchasing ready-to-wear jackets, the S-group and the M-group considered shoulder width important, while the L-group considered chest circumference the most important area. When evaluating the fit of ready-to-wear jackets, the L-group evaluated chest circumference, back width, and waist circumference as poor fits. The M-group evaluated sleeve length and shoulder width as poor fits, and the S-group agreed with respect to sleeve length. Body-satisfaction levels and matching jacket-satisfaction levels differed by body-size group, as did areas that need improvement. The conclusion is that size-group analysis using 3D body scanning can be utilized effectively for jacket-fit analysis. The findings of the current study can be applied to improving jacket fit among young male consumers.

• 한국생활과학회지
• /
• 제23권6호
• /
• pp.1191-1204
• /
• 2014

Even though a Han-bok, or traditional Korean costume, should be inherited since it is invaluable part of our culture, research on Han-bok is scarce. Since the development of a Jeogori pattern, the upper garment of Korean traditional clothes, is done mostly based on the chest size, the design does not completely consider on wearer's body shape. Moreover, unless made by an expert, trial and error is almost always necessary to improve the fit of the clothes. In this research, a Jeogori pattern was suggested that improves the fit based on the shape of the upper back(straight or bent) of a female in her late 20s who often wears a Han-bok and is comfortable when moving. Using a 3D virtual clothing system, the optimum pattern was selected based on the body shape. The final selection was made, and each subjects tried the garment on to evaluate the comfort when moving, along with its appearance, based on a seven point Likert scale. As a result, for a straight body shape, the optimum ease for the front bust width was 2.5cm, and that for the back bust width was 2.0cm. The optimum center back dart was 1.0cm. The optimum Geodae width was 7.6cm, and the optimum back Geodae point was 2.0cm. For the bent body shape, the optimum ease for the front and back bust was 2.0cm. The optimum Geodae width was 8.4cm, and the optimum back Geodae point was 1.5cm. Furthermore, if the Hwajang slope was set at half of the vertical distance between the laterals of the neck and shoulder, a fitted silhouette appeared, which is preferred nowadays. In the appearance evaluation, the final pattern designed in this research received higher scores than the original design(straight; p<.001, bent; p<.05). The results of the evaluation of the comfort when moving also showed higher scores for the final pattern that was designed.

• 한국의상디자인학회지
• /
• 제5권1호
• /
• pp.13-24
• /
• 2003

The purpose of this study is to design Jugori model compatible with the body types of the middle-aged women especially from 40 to 59 years old. The result is as follows: We decided five items as the necessary items for designing jugori model : the bust girth (the breast & shoulder width), the B.P length, the neck width, the armhole circumference, and Hwa-jang. The breast & shoulder width are the size that comes out if the bust is divided by the breast & shoulder width on the basis of the side line, and Hwa-jang is a length measured with arms stretched out to 0° direction. With each person's physical characteristics considered, the application of the size of each body types and body parts is as follows: 1. The breast & shoulder width (1/4 portion) : We decided B/4+2cm as a standard size and, we adjusted the extra room on the basis of the discrepancy between the breast width and the shoulder width to make it fit well to the each body type. For the breast width (1/2 portion), we bisected the difference between the breast width and the shoulder width of the bust, and moved Gut-sup to the center of the Sup and Sup-sun for An-sup. According to the body type, the movement of the Sup for the people with big breasts gets bigger because there should be a big difference between the breast width and the shoulder width for them, and for the people with small breasts the movement will be relatively smaller. For the shoulder width (1/2 portion), we curved the back center line after we shortened as much as the difference between the amount of the shoulder width/2+1cm and of B/4+2cm. The movement of back center line will be bigger for a person with leaned-backward body type. 2. The front & back length: We made the front length to B.P length+2.5cm to have Jugori cover the breast point fully around the bust line, which is a vogue nowadays. For an upright body type, we decided the back length as (AH/2.2)+5cm. And for a bent-forward and a leaned-backward body type, we adjusted the calculation formulae differently taking the physical characteristics into account. We decided the back length (A) as (A.H/2.2)+5cm, and the front length (B) as the back length+5cm. So, (A+B) is the sum of the front length and the back length. Going back to the original formula, the front length is B.P+2.5cm. So, we can decide the back length if we subtract B.P+2.5cm from the sum of the front length and the back length. To make well-fit Jugoris, the front & back length are areas that we should pay attention to if we take each person's physical characteristics into consideration. 3. Go-dae (1/2 portion) : We decided Go-dae as the neck width/2+0.5cm. For an upright body type, because the base line which went down vertically from the tragion was straight, we generally decided Go-dae Dalim line as 1.0cm. But we decided Go-dae Dalim line down to 1.5cm for bent-forward type and up to 0.2cm for leaned-backward type because the upper half of the body of them was bent forward or leaned backward from the base line. 4. The armhole : We decided the armhole circumference as A.H/2+2cm with the whole extra room of 4cm. 5. The side line length : We can calculate the side line length to (the back length-the armhole)/2, and, in terms of the trend, 2.5cm will be appropriate.

• Bulletin of the Korean Chemical Society
• /
• 제33권2호
• /
• pp.393-397
• /
• 2012

We report a new route to synthesize high quality zinc blende CdS and ZnS nanocrystals in noncoordinating solvent 1-octadecene, using dodecanethiol (DDT) molecules as both the sulfur source and surface capping ligands. Different reaction temperatures and Cd(Zn)/DDT molar ratios were tested to optimize the synthesis conditions. Absorption photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) pattern, and transmission electron microscopy (TEM) were used to characterize assynthesized nanocrystals. The narrow half width at the half-maximum on the long wavelength side of the firstexcitonic absorption peak and TEM images demonstrated nearly monodisperse size distributions of asprepared CdS, ZnS, and CdS/ZnS core/shell nanocrystals. Only trap emissions of the nanocrystals were detected when the amount of DDT was excessive, this came from the strong quenching effect of thiol groups on the nanocrystal surfaces. After overcoating with ZnS shells, band-gap emissions of CdS nanocrystals were partially recovered.

• 대한전자공학회논문지SD
• /
• 제41권1호
• /
• pp.1-8
• /
• 2004

Quantized memory addressing (QMA) 이론을 바탕으로 새로운 PDP 계조 구현을 수행하는 방법을 개발하였다. 어드레스 펄스 폭을 조절함에 따라 셀에 기입되는 벽전하 양은 "fully on", "off" 그리고 "half on"의 세 단계를 가지게 된다. 이 세 단계의 벽전하를 이용하여 7개의 서브필드로 255단계의 계조를 표현할 수 있다. 더욱이 기존의 구동 방법과는 달리 인접한 두 계조를 표현하기 위해 사용하는 서브필드들이 동영상 의사윤곽을 제거한다. 이 방법은 7개의 서브필드를 사용함으로써 12개의 서브필드를 이용하여 동영상 의사 윤곽을 저감시킨 방법에 비해 유지 방전 시간을 $70\%$이상 증가시킨다.

• Journal of Power Electronics
• /
• 제15권6호
• /
• pp.1429-1437
• /
• 2015

A new parallel hybrid soft switching converter with low circulating current losses during the freewheeling state and a low output current ripple is presented in this paper. Two circuit modules are connected in parallel using the interleaved pulse-width modulation scheme to provide more power to the output load and to reduce the output current ripple. Each circuit module includes a three-level converter and a half-bridge converter sharing the same lagging-leg switches. A resonant capacitor is adopted on the primary side of the three-level converter to reduce the circulating current to zero in the freewheeling state. Thus, the high circulating current loss in conventional three-level converters is alleviated. A half-bridge converter is adopted to extend the ZVS range. Therefore, the lagging-leg switches can be turned on under zero voltage switching from light load to full load conditions. The secondary windings of the two converters are connected in series so that the rectified voltage is positive instead of zero during the freewheeling interval. Hence, the output inductance of the three-level converter can be reduced. The circuit configuration, operation principles and circuit characteristics are presented in detail. Experiments based on a 1920W prototype are provided to verify the effectiveness of the proposed converter.