• 한국수자원학회논문집
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• 제51권9호
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• pp.783-793
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• 2018

본 연구의 목적은 한국의 지역별 연평균 강우침식인자 값을 갱신하기 위한 것이다. 2012년 환경부는 표토의 침식 현황조사에 관한 고시를 공포하면서 전국 규모의 토양침식량을 추정하기 위한 모델로서 범용토양유실공식 모델을 채택한 바 있다. 이 고시에는 범용토양유실공식을 적용하기 위해 필요한, 158개 지점에 대한 지역별 강우침식인자가 포함되어 있으나, 이 값은 1997년 이전에 만들어진 데이터를 바탕으로 하고 있기에 개선될 필요가 있다. 본 연구는 우리나라 전국 단위의 연평균 강우침식인자 데이터를 수집하고 분류, 통합하여 분석에 사용하였다. 연구결과 1961~2015년 기간의 54개 지점에 대한 연평균 강우침식인자를 재산정하였으며 새로운 등강우침식도를 제시하였다. 또한 실무에서 활용이 용이하도록 국내 167개 시 군별 연평균 강우침식인자 데이터를 제시하였다. 본 연구에서 제시한 값은 표토침식량을 예측하기 위한 업데이트된 강우침식인자로 활용될 수 있을 것이다.

• 한국식품과학회지
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• 제16권2호
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• pp.182-184
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• 1984

감마선(線) 조사(照射)와 자연저온(自然低溫)에 의한 송이 저장법(貯藏法) 개발(開發)을 목적(目的)으로 $1{\sim}2.5kGy$ 범위(範圍)의 감마선(線)을 조사(照射)하고 자연저온(自然低溫) 저장고(貯藏庫)에 저장(貯藏)하면서 이화학적(理化學的) 변화(變化)를 조사(調査)하였다. 비조사구(非照射區)에서는 저장(貯藏) 7 일(日)에 97%의 갓이 피었고, 28%의 높은 부패율(腐敗率)을 나타내었으나 적정선량(適正線量)이라고 생각되는 $2{\sim}2.5kGy$ 조사구(照射區)에서는 5%의 갓핌과 $5{\sim}8%$의 낮은 부폐율(腐敗率)을 보였으며, 중량감소(重量減少), texture 및 내부(內部)의 변색(變色)에 있어서도 조사구(照射區)는 비조사구(非照射區) 보다 우수하여 10일(日) 이상(以上)의 저장기간(貯藏期間)을 연장(延長)할 수 있었다. 화학성분(化學成分) 변화(變化)에 있어서는 선량(線量)의 증가(增加)와 더불어 환원당(還元糖)이 약간증가(增加)하였고 ascorbic acid는 감소(減少)하였으며 다른 성분(成分)에 있어서는 별차이(別 差異)가 없었다.

• 한국전자파학회논문지
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• 제12권7호
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• pp.1086-1093
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• 2001

본 논문에서는 n차 오차신호발생기(error signal generator)를 이용한 postdistortion 방식의 RF 전력증폭기의 선형화 기법을 제안하였다. n차 ESG(error signal generator)는 전력증폭기의 기저대역 등가 복소 전달함수를 바탕으로 오차신호를 발생시켜, 이를 전력증폭기의 출력 단에서 n차 이하의 비선형성만을 제거한다. 따라서, 출력 단의 n차 이상의 혼변조 왜곡(intermodulation distortion) 성분에 영향을 미치지 않으며, 개루프(open-loop) 형태이므로 시스템의 안정성을 보장할 수 있다. 또한, 전력증폭기의 입력 신호를 이용하여 오차신호를 발생시키므로 feedforward 방식에서와 같이 오차신호 발생에 따른 주신호 경로(main signal path)의 시간지연 회로가 불필요하다. 실험 결과로 7차 ESG를 이용한 postdistorter를 최대 출력이 5 W인 셀룰러 대역 A급 증폭기에 적용한 경우의 혼변조 왜곡 개선도와 3-carrier CDMA 신호를 이용한 측정 결과를 제시하여 본 방법의 타당성을 검증하였다.

• 한국대기환경학회지
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• 제27권4호
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• pp.454-459
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• 2011

In this study, the recovery rate of Tedlar bag (T) sampler was investigated in comparison to polyester aluminum bag (P) sampler. To derive the comparative data sets for the relative performance between different samplers, a series of calibration experiments were performed by using 1 ppb standard of four offensive reduced sulfur compounds (RSC) odorants ($H_2S$, $CH_3SH$, DMS, and DMDS) along with $SO_2$ and $CS_2$. All the analysis was made by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server/thermal desorber (AS/TD). The measurement data were obtained by loading gaseous standards (1 ppb) at 3 injection volumes (250, 500 and 1,000 mL) at three intervals (0, 24 and 72 hrs). The recovery rates (RR) of P sampler were computed against the slope values of T sampler. According to our analysis, P sampler exhibits slightly enhanced loss relative to T, especially with light RSCs ($H_2S$ and $CH_3SH$). At day 0, RR for the two were 88 and 85%, respectively. Such reduction proceeded rather rapidly in the case of $H_2S$ through time. However, P sampler was more stable to store $SO_2$ unlike others. Despite slightly reduced recovery, P sampler appears as a good replacement of T sampler.

• 한국전기전자재료학회논문지
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• 제26권3호
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• pp.246-251
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• 2013

Screen printing is commonly used to form the front/back electrodes in silicon solar cell. But it has caused high resistance and low aspect ratio, resulting in decreased conversion efficiency in solar cell. Recently the plating method has been combined with screen-printed c-Si solar cell to reduce the resistance and improve the aspect ratio. In this paper, we investigated the effect of light induced silver plating with screen-printed c-Si solar cells and compared their electrical properties. All wafers were textured, doped, and coated with anti-reflection layer. The metallization process was carried out with screen-printing, followed by co-fired. Then we performed light induced Ag plating by changing the plating time in the range of 20 sec~5min with/without external light. For comparison, we measured the light I-V characteristics and electrode width by optical microscope. During plating, silver ions fill the porous structure established in rapid silver particle sintering during co-firing step, which results in resistance decrease and efficiency improvement. The plating rate was increased in presence of light lamp, resulting in widening the electrode with and reducing the short-circuit current by shadowing loss. With the optimized plating condition, the conversion efficiency of solar cells was increased by 0.4% due to decreased series resistance. Finally we obtained the short-circuit current of 8.66 A, open-circuit voltage of 0.632 V, fill factor of 78.2%, and efficiency of 17.8% on a silicon solar cell.

• 한국통신학회논문지
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• 제29권12C호
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• pp.1601-1605
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• 2004

연속적인 최대 천이 길이(j)를 2 이하로 제한하는 MTR 코드를 사용할 경우, 4차의 부분 응답 최대 유사도 (PRML) 검출기의 성능은 기존의 일반적인 코드를 사용한 경우에 비해 현저히 향상될 수 있으나, 낮은 코드율로인해 코드율 손실이 생긴다. 본 논문에서는 코드워드 자체에서는 MTR 구속 조건이 2를 만족하면서 코드워드를 연결하였을 때에는 j=3을 허용하는 코드율이 7/8인 코드에 대해 i=2와 j=3인 형태의 트렐리스를 결합시켜 변형된 형태의 PRML 검출 방법을 제안하였다. 이러한 결합된 트렐리스를 갖는 변형된 형태의 4차 PRML 검출 방법은 높은 기록 및도의 수평 또는 수직 자기기록 시스템에서 기존의 코드율 8/9인 코드에 대한 4차 PRML 검출 방법에 비해 10-5 BER에서 최소 2dB 이상의 SNR 성능 이득을 보임을 확인하였다.

• Archives of Plastic Surgery
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• 제38권5호
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• pp.655-662
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• 2011

Purpose: The anterolateral thigh flap is versatile flap for soft-tissue reconstruction for defects located at various sites of the body. This useful flap offers a thick and vascular fascia lata component with large amounts that can be soft tissue coverage for different reconstructive purposes. We present our clinical experience with the use of vascular fascia lata, combined with anterolateral thigh flap for various reconstructive goals. Methods: From April 2008 to February 2011, we transferred anterolateral thigh flaps with fascia lata component to reconstruct soft-tissue defects for different purposes in 11 patients. The fascia lata component of the flap was used for tendon gliding surface in hand/forearm reconstruction in 4 patients, for reconstruction medial and lateral patellar synovial membrane and retinaculum in 2 patients, for reconstruction of plantar aponeurosis in the foot in 2 patients, for reconstruction of fascial and peritoneal defect in the abdominal wall in 2 patient, and for dural defect reconstruction in the scalp in the remaining one. Results: Complete loss of the flap was not seen in all cases. Partial flap necrosis occurred in 2 patients. These complications were treated successfully with minimal surgical debridement and dressing. Infection occurred in 1 patient. In this case, intravenous antibiotics treatment was effective. Conclusion: Anterolateral thigh flap has thick vascular fascia with large amounts. This fascial component of the flap is useful for different reconstructive aims, such as for tendon, ligament, aponeurosis defects, abdominal wall or dura reconstruction. It should be considerated as an important advantage of the flap, together with other well-known advantages.

• Journal of Chest Surgery
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• 제44권1호
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• pp.25-31
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• 2011

Background: Mature autogenous arteriovenous fistulas have better long term patency and require fewer secondary interventions compared to arteriovenous prosthetic graft. Our Study evaluated vascular patency rates and incidence of interventions in autogenous arteriovenous fistulas and grafts. Material and Methods: A total of 166 vascular access operations were performed in 153 patients between December 2002 and November 2009. Thirty seven caeses were excluded due to primary access failure and loss of follow-up. One group of 92 autogenous arterioveous fistulas and the other group of 37 arteriovenous prosthetic grafts were evaluated retrospectively. Primary and secondary patency rates were estimated using the Kaplan-Meier method. Results: The primary patency rate (84%, 67%, 51% vs. 51%, 22%, 9% at 1, 3, 5 year; p=0.0000) and secondary patency rate (96%, 88%, 68% vs. 88%, 65%, 16% at 1, 3, 5 year; p=0.0009) were better in autogenous fistula group than prosthetic graft group. Interventions to maintain secondary patency were required in 23% of the autogenous fistula group (average 0.06 procedures/patient/year) and 65% of prosthetic graft group (average 0.21 procedures/patient/year). So the autogenous fistula group had fewer intervention rate than prosthetic graft group (p=0.01) The risk factor of primary patency was diabetus combined with ischemic heart disease and the secondary patency's risk factor was age. Conclusion: Autogenous arteriovenous fistulas showed better performance compared to prosthetic grafts in terms of primary & secondary patency and incidence of interventions.

• Journal of Korean Neurosurgical Society
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• 제37권5호
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• pp.340-344
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• 2005

Objective: Posterior lumbar interbody fusion(PLIF), the current leading method of pedicle screw fixation combined with interbody fusion via posterior route, sometimes requires too much destruction of the facet joint than expected especially for the patient with a narrow spine. On the other hand, tranforaminal lumbar interbody fusion(TLIF) technique provides potential advantages over PLIF and can be chosen as a better surgical alternative to more traditional fusion methods in certain surgical conditions. Methods: From October 1999, 99 PLIF and 29 TLIF procedures were done for the patients with spinal stenosis and instability. Radiological data including the interpedicular distance and the size of the pedicles as well as the clinical parameters were collected retrospectively. The degree of resection of the inferior articular process was compared with the interpedicular distance in each patient who received PLIF. Results: No significant differences were found between PLIF and TLIF regarding the operation time, blood loss, duration of hospital stay, or short term postoperative clinical result. There were no complication with TLIF, but PLIF resulted in 9(9.1%) complications. During PLIF procedure, all patients(n=24) except one with the interpedicular distance shorter than 27mm required near complete or complete resection of the inferior articular processes, whereas only 6(31.5%) of 19 patients with the interpedicular distances longer than 30mm required the similar extent of resection. Conclusion: TLIF is better than PLIF in terms of the complication rate. The patient who had narrow interpedicular distance(<27mm) might be better candidate for TLIF.

• Journal of Korean Neurosurgical Society
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• 제60권4호
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• pp.456-464
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• 2017

Objective : Although little is known about its origins, neck pain may be related to several associated anatomical pathologies. We aimed to characterize the incidence and features of chronic neck pain and analyze the relationship between neck pain severity and its affecting factors. Methods : Between March 2012 and July 2013, we studied 216 patients with chronic neck pain. Initially, combined tramadol (37.5 mg) plus acetaminophen (325 mg) was administered orally twice daily (b.i.d.) to all patients over a 2-week period. After two weeks, patients were evaluated for neck pain during an outpatient clinic visit. If the numeric rating scale of the patient had not decreased to 5 or lower, a cervical medial branch block (MBB) was recommended after double-dosed previous medication trial. We classified all patients into two groups (mild vs. severe neck pain group), based on medication efficacy. Logistic regression tests were used to evaluate the factors associated with neck pain severity. Results : A total of 198 patients were included in the analyses, due to follow-up loss in 18 patients. While medication was successful in reducing pain in 68.2% patients with chronic neck pain, the remaining patients required cervical MBB. Lateral cervical curvature, such as a straight or sigmoid type curve, was found to be significantly associated with the severity of neck pain. Conclusion : We managed chronic neck pain with a simple pharmacological management protocol followed by MBB. We should keep in mind that it may be difficult to manage the patient with straight or sigmoid lateral curvature only with oral medication.