• 동력기계공학회지
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• 제19권2호
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• pp.33-39
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• 2015

In conducting indoor positioning by code division multiple access using spread spectrum ultrasonic waves, it is required to detect signals under the influence of near-far problem occurred by difference on signal power, caused by distance between transmitter and receiver. For discussing robustness to the problem, we verified measuring accuracy on distance from an experiment on a real space with a hardware device where our proposed method is mounted. The proposed method performs automatic signal detection by setting threshold level dynamically. As an experimental result, measurable distance were improved by the proposed method, and measurement errors were up to 50mm in distances from 1000mm to 6000mm; therefore, enough accuracy to realize self-localization or navigation for autonomous mobile robot or human was obtained.

• 대한임상검사과학회지
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• 제39권2호
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• pp.96-103
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• 2007

This study was carried out on 14,443 subjects (8,706 men, 5,737 women ; between 20-80 years of age, mean age $41.8{\pm}9.16$) who visited the health promotion center of one university hospital. Serum $T_3$, $T_4$ and TSH concentrations were measured with CIA using commercial kits on ADVIA Centaur Assay. The prevalence of thyroid disfunction was high in elderly people and women like in western countries. The results were as follows; 1. The prevalence of overt hyperthyroidism was 4.8/1,000 population (men 4.1/1,000, women 5.9/1,000) and was higher in women than in men. 2. The prevalence of subclinical hyperthyroidism was 10.7/1,000 population (men 9.0/1,000, women 13.2/1,000) with peak prevalence at the age group 50, 60 and was higher in women than in men. 3. The prevalence of overt hypothyroidism was 0.5/1,000 population (men 0.5/1,000, women 0.5/1,000). The prevalence increased with age and was significantly higher in women in the age group over 60 years. 4. The prevalence of subclinical hypothyroidism was 12.6/1,000 population (men 6.0/1,000, women 22.7/1,000) and was as high as about 4 times in women than in men. 5. The prevalence of thyroid dysfunction was higher in women than in men in all the age groups, and was higher in the age group 50, 60 years than in any other age group.

• Wind and Structures
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• 제4권1호
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• pp.73-84
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• 2001

Analysis of pressures measured on the roof of the full-scale Texas Tech building and a 1/50 scale model of a typical house showed that the pressure fluctuations on cladding fastener and cladding-truss connection tributary areas have similar characteristics. The probability density functions of pressure fluctuations on these areas are negatively skewed from Gaussian, with pressure peak factors less than -5.5. The fluctuating pressure energy is mostly contained at full-scale frequencies of up to about 0.6 Hz. Pressure coefficients, $C_p$ and local pressure factors, $K_l$ given in the Australian wind load standard AS1170.2 are generally satisfactory, except for some small cladding fastener tributary areas near the edges.

• 방사선산업학회지
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• 제3권1호
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• pp.31-37
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• 2009

This paper describes the preparation of manufacturing a new nanocomposite material, which involves adding a multi walled carbon nanotube (MWCNT) to improve thermal characteristics of poly (ethylene-co-vinyl acetate) (EVA). We irradiated the prepared nanocomposites with doses of 50 kGy, 100 kGy and 200 kGy at a dose rate of $5kGy\;hr^{-1}$ and examined their thermal stability, activation energy and crosslink level by using a thermogravimetric analyzer (TGA) and gel fraction experiments. TGA results indicated that the samples with a MWCNT had higher Derivative Thermo Gravimetry (DTG) 2nd peak temperatures than those without a MWCNT. And activation energy of the samples reduced as the absorption dose and the MWCNT content increased. Finally, the gel fraction increased rapidly up to 100 kGy as total absorption dose increased, and then the growth rate of all samples was slowly increased from 100 kGy.

• 전자공학회논문지
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• 제50권12호
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• pp.56-62
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• 2013

우리는 MOSFET Layout 단계에서 Multiplier 구성을 통한 Common centroid layout 방식을 사용한 무선 전력 전송 용 CMOS 정류회로를 제안한다. 제안하는 정류회로는 기존의 다이오드를 사용하지 않은 Cross-coupled MOSFET 정류회로로 13.56 MHz에서 동작한다. 전력 소모를 최소화하고, 높은 주파수까지 동작하기 위하여 Full bridge 정류회로에서 효율을 높이기 위한 비교기를 제거하였다. Layout 단계에서 Multiplier 구성을 통한 Common centroid layout 방식은 Chip-layout 상에서 MOSFER의 Finger에 의해 길어진 연결 선로에 존재하는 기생 직렬 저항과 병렬 Capacitor에 의해 발생하는 시간 지연을 줄이기 위해 고안되어, 천이 시간을 줄여 Cross-coupled 구조의 On-상태에서 Off-상태, 혹은 그 반대의 상태 변화를 빠르게 한다. 이는 빠른 상태 변화 시간으로 인해 전력 변환 효율을 증가시킨다. 본 정류회로는 $0.11{\mu}m$ CMOS 공정으로 제작되었으며, 전력 변환 효율은 최대 86.4%로 측정되었으며, 600 MHz 이상까지 높은 전력 변환 효율을 가지며, 이는 현재 발표된 것 중, Cross-coupled 구성을 기반으로 한 정류회로 중 가장 높은 성능을 가진다.

• 대한토목학회논문집
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• 제4권1호
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• pp.103-112
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• 1984

본(本) 연구(硏究)는 단위유량도이론(單位流量圖理論)에 근거하여 소하천유역(小河川流域)의 계획홍수량(計劃洪水量)을 결정할 수 있는 일련(一聯)의 경험적(經驗的)인 절차(節次)를 개발한 것이다. 특정재현기간(特定再現期間)의 홍수량(洪水量)은 유역면적(流域面積)에 재현기간(再現期間)에 해당되는 강우능계수(降雨能係數)와 강우특정기간별(降雨特精期間別) 유출능계수(流出能係數) 및 첨두홍수량(尖頭洪水量) 감소계수(減少係數)의 곱으로 표시(表示)하였다. 강우능계수(降雨能係數)와 유출능계수(流出能係數)의 결정방법(決定方法)은 본(本) 연구이전(硏究以前)에 수행된 연구(硏究)(13)에서 정립(定立)된 바 있어 본(本) 연구(硏究)에서는 첨두유량감소계수(尖頭流量減少係數)를 결정하는 방법(方法)을 개발(開發)한 후 경안천(慶安川)의 한 지점유역(地點流域)에 대한 50년홍수량(年洪水量)을 이 방법(方法)으로 산정(算定)하여 이를 타홍수량(他洪水量) 추정방법(推定方法)과 비교(比較) 검토(檢討)하였다. 첨두홍수량(尖頭洪水量) 감소계수(減少係數)는 면적집성법(面積集成法)에 의해 유도된 소유역별(小流域別) 단위도(單位圖)로부터 산정(算定)된 유역(流域)의 지체시간(遲滯時間) 대비(對比) 강우(降雨)의 특정시간(特精時間)을 변량(變量)으로 하여 상관관계(相關關係)가 수립되었으며, 지체시간(遲滯時間)은 유역(流域)의 지형인자(地形因子)인 유로연장(流路延長) 및 평균유로경사(平均流路傾斜)와 상관(相關)시켰다.

• 한국양식학회지
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• 제19권2호
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• pp.125-132
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• 2006

본 실험은 볼락 종묘를 안정적으로 대량 생산하는 데 필 수적인 자치어기의 성장과 소화효소인 trypsin, pepsin-like enzyme, amylase 그리고 lipase의 activity를 측정하여 소화생리에 대한 기초 자료를 제공하고자 수행하였다. 산출 직후 자어의 체장은 $5.01{\pm}0.22 mm$이었던 것이 산출 후 100일에는 $36.01{\pm}1.22 mm$ 까지 성장하였고, 습중량은 산출 후 70일 전후로 급격히 증가하였다. trysin 활성은 산출후 2일째 처음으로 확인되어 $7.00{\pm}1.48$ unit을 나타내고 산출후 66일 $1425{\pm}230$ unit으로 peak를 나타내었다. pepsin-like enzyme 활성은 산출 후 11일째 처음으로 확인되었고 산출후 66일째 $902{\pm}160$ unit까지 급격히 증가하였다. Lipase 활성은 산출후 2일째 $4.5{\pm}1.4$ unit으로 확인되었고 산출후 47일계에는 $38.3{\pm}0.4$unit로 peak를 나타내었다. Amylase 활성은 산출후 11일째 $0.18{\pm}0.11$ unit으로 처음 확인되었고 산출후 50일째 $23.48{\pm}5.11$ unit까지 급격히 증가하였다. specific activity는 trypsin이 산출후 14일째, pepsin-like enzyme이 61일째 peak를 나타냈다. 볼락의 체중이 현저하게 증가하는 시기에 맞춰서 각 효소와 전활성이 급격히 상승하는 것을 확인 할 수 있었다. 이것은 이시기가 위선이 기능적으로 역할을 하는 시기와 일치하므로 단백질 소화능력의 비약적인 증가가 체중 증가에 크게 관여하였음을 나타낸다. 그러므로 본 실험에서 확인 된 체중이 급격히 증가하는 시기는 볼락 양식에 있어서 사료 전환기 즉, 생물사료에서 배합사료로 전환하기에 적당하다고 할 수 있겠다.

• 한국초지조사료학회지
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• 제30권4호
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• pp.291-300
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• 2010

본 연구는 쉽 페스큐 50%와 야생화 50%의 파종비율로 조성한 야생화초지의 생육특성, 계절분포 및 식생비율을 구명하고자 충남대학교 내 초지시험포장에서 2007년 10월부터 2009년 12월까지 수행하였다. 공시초종은 기본초종인 잔디형 목초로 쉽 페스큐(Azure)와 국내산 야생화 4종과 외국산 야생화 29종 등 총 33종을 공시하였다. 야생화의 개화당시의 평균초장은 1년차 30.0 cm, 2년차 35.6 cm 이었다. 꽃 색은 10가지로 다양하게 개화되었으나 8월, 9월 및 10월에는 단순화되었다. 개화는 5~6월에 절정을 이루었으나, 8월부터 10월까지는 편중되는 양상이 뚜렷하였다. 특히, 2년차(2009)에는 월동 후 일년생 야생화초종의 식생감소로 야생화의 꽃 색, 계절분포 및 영속성이 문제시 되었다. 야생화초지의 연평균 식생비율은 야생화, 쉽 페스큐 및 잡초가 각각 1년차(2008)에는 28%, 55% 및 17%이었고, 2년차(2009)에는 각각 24%, 60% 및 16%를 유지하였다. 이상의 결과로 보아 쉽 페스큐와 야생화의 파종비율을 50:50%의 비율로 야생화초지를 조성할 경우는 단기간(1년)에 공원 및 하천변과 같은 평탄지를 대상으로 경관을 목적으로 조성할 경우에 더 적합한 방법으로 판단된다.

• Korean Circulation Journal
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• 제54권6호
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• pp.325-335
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• 2024

Background and Objectives: The number of sensitized heart failure patients on waiting lists for heart transplantation (HTx) is increasing. Using the Korean Organ Transplantation Registry (KOTRY), a nationwide multicenter database, we investigated the prevalence and clinical impact of calculated panel-reactive antibody (cPRA) in patients undergoing HTx. Methods: We retrospectively reviewed 813 patients who underwent HTx between 2014 and 2021. Patients were grouped according to peak PRA level as group A: patients with cPRA ≤10% (n= 492); group B: patients with cPRA >10%, <50% (n=160); group C patients with cPRA ≥50% (n=161). Post-HTx outcomes were freedom from antibody-mediated rejection (AMR), acute cellular rejection, coronary allograft vasculopathy, and all-cause mortality. Results: The median follow-up duration was 44 (19-72) months. Female sex, re-transplantation, and pre-HTx renal replacement therapy were independently associated with an increased risk of sensitization (cPRA ≥50%). Group C patients were more likely to have longer hospital stays and to use anti-thymocyte globulin as an induction agent compared to groups A and B. Significantly more patients in group C had positive flow cytometric crossmatch and had a higher incidence of preformed donor-specific antibody (DSA) compared to groups A and B. During follow-up, group C had a significantly higher rate of AMR, but the overall survival rate was comparable to that of groups A and B. In a subgroup analysis of group C, post-transplant survival was comparable despite higher preformed DSA in a desensitized group compared to the non-desensitized group. Conclusions: Patients with cPRA ≥50% had significantly higher incidence of preformed DSA and lower freedom from AMR, but post-HTx survival rates were similar to those with cPRA <50%. Our findings suggest that sensitized patients can attain comparable post-transplant survival to non-sensitized patients when treated with optimal desensitization treatment and therapeutic intervention.

• 설비공학논문집
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• 제20권12호
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• pp.802-807
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• 2008

A Study on Typical Rates of Water-use for School Facilities has been carried out in this work. Water supply system is given much weight in school facilities. Therefore, it set up a basis efficiency using of water sources to calculate typical rates of water use. The results are summarized as follows; 1) On the whole, typical rates of water-use was founded out 15 L/stu. d in pirmary school, 10 L/stu. d in middle school and 30 L/stu. d in high school smaller than the existing it. It was rate of water-use change as season and Max. Rates of water-use was July. 2) I deem that school hours are 5 hour's in primary school, 7 hour's in middle school and 8 hour's in high school. It the concept of 1 hour that is lesson time 40 minutes and resting time 10 minutes in primary school, lesson time 45 minutes and resting time 10 minutes in middle school and lesson time 50 minutes and resting time 10 minutes in high school. 3) It is desired that we calculate the volume of pump and water tank throughout this concept and the size of water tank should be 1.5 times with taking peak load into consideration by this study on typical rate of water-use. 4) The amount of using water increases in gradually and I consider the life cycle of facilities is more than 10 years. As a result, I can forecast that the size will be insufficiency but I deem that if we devise a plan about parallel pumping on water tank space, we can cope with it. Also, it is expected that we can cut back the transport energy by controlling pump volume.