• 한국대기환경학회지
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• 제19권6호
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• pp.689-699
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• 2003

This study was to examine characteristics of treating toluene vapor, which gets to be problematic due to its harmful carcinogenicity and mass generation from various sources, through a biological treatment facility which is environment-friendly and adopts a high-efficient and low-cost clean technology. In order to identify whether Alnus Firma Fruit (AFF) can be used as a media for a bioreactor, its utility and basic operating factors, a study was conducted on pressure drop, supply of nutrient substances and retention time which are operating factors of a biofilter, and eliminating characteristics were compared between AFF and the conventional biological activatedcarbon (BAC) widely used as filter media. In the case of AFF, the initial microbial deposits was 2.3${\times}$10$^{7}$ CFU/g dry AFF, which represents the initial microbial density higher than the case of BAC showing 5.5${\times}$10$^{6}$ CFU/g dry BAC And it took about 2 weeks to acclimate until its eliminating rate got to be increased over 90%. As a result of comparing pressure loss taking place with the lapse of time between BAC and AFF, after 130 days passed at SV 25h$^{-1}$ , BAC showed that its eliminating efficiency had a tendency to drop greatly due to a great pressure loss (0.53\longrightarrow54.7 mm$H_2O$/m) caused by an excess of biomass as accumulated. On the other hand. AFF showed that the pressure drop was 0.53 mm$H_2O$/m, about 2 times as much as the initial pressure loss of 0.4 mm$H_2O$/m, which represents no great change in the pressure loss, and its eliminating efficiency was also shown to be continuously high. Therefore, when AFF was used as a filler for a biological treatment facility, a biological filter enabling improvement of the purifying efficiency to be promoted could be provided, and moreover, the pressure loss was so small that the filler replacement cycle or the back flushing cycle could be extended. So, even in terms of the operating cost, it was identified to be an economical filler When an inorganic material was used as a filler, the biofilters performance acted sensitively on whether nutrient substances were supplied or not. In the case of AFF with low adsorptivity, addition of ethyl-alcohol increased the solubility of toluene, and consequently, biodegradation got to be actively made by microbes, and thus, its eliminating rate could be increased. As the flow velocity and the inflow concentration got to be more increased, its eliminating rate got to be lower, and particularly, an increase in the flow velocity made its eliminating rate drop more greatly than an increase in the concentration.

• Journal of Ginseng Research
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• 제29권2호
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• pp.113-118
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• 2005

본 연구는 수삼의 저장용기로 많이 이용되고 있는 플라스틱 상자의 통기구 비율 즉 개공율이 수삼의 저장성에 미치는 영향을 조사하기 위하여 개공율을 밀폐(0), 1, 3, 5, 및 $10\%$로 설정하여 실온에서$(19\~23^{\circ}C,\;RH\;40\~61\%)$ 10일간, 냉장으로$(4\~9^{\circ}C,\;RH\;72\~92\%)$ 30일간 저장하면서 이 화학적 변화를 조사한 결과는 다음과 같다. 실온에서 외관변화는 밀폐구에서 4일 부터 곰팡이 발생이 관찰되며 10일째는 부패하였고, $1\%$는 8일부터 곰팡이 발생이 관찰되었다. $5\%$와 $10\%$ 개공율은 4일부터 시들기 시작하였다. 중량감모율은 개공율이 높을수록 많이 나타나 $5\%$와 $10\%$개공율에서 4일후 $10\%$이상 나타났다. 유리당은저장기간의 경과에 따라 maltose와 sucrose가 감소하였는데 개공율이 낮을 수록 많이 감소하였다. 냉장에서 곰팡이 발생은 관찰되지 않았으며 중량모율은 $5\%$와 $10\%$ 개공율에서 12일부터 약 $10\%$를 보이면서 시들기 시작하였으며, 밀폐와 $1\%$는 30일간 저장기간에서도 양호한 외관상태를 보였다. 유리당중 maltose는 감소, sucrose는 감소하였다가 증가하는 경향을 보였다. 이상의 결과에서 보관상자의 개공율을 조절하여 수삼의 저장성을 향상시킬 수 있음을 알 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제36권4호
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• pp.459-466
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• 2012

엔진성능 분석을 위해서는 기관의 정확한 출력이 기본적으로 중요한 인자이며, 또한 오늘날 엔진의 연소압력 분석 장치는 엔진의 연구와 개발, 환경규제 및 엔진의 유지관리를 위해서 필수 장비로 대두 되고 있다. 디젤엔진에서 성능 분석의 정확도는 TDC의 위치를 정확하게 찾는 것이 무엇보다 중요하다. 따라서 본 연구에서는 2행정 대형저속의 선박엔진에서 TDC의 위치에 영향을 주는 인자들의 영향을 조사 분석하고, 정확한 TDC 위치를 파악하기 위한 새로운 방법을 제시하고자 한다. 전보에서 정확한 엔진 출력은 TDC위치의 정확도에 의해서 결정이 되며, '시간기준 계측' 방법 보다 '각도기준 계측' 방법이 정확도 측면에서 우수함을 밝혔다. 또한 압축압력의 피크는 열손실 및 Blow by에 의한 가스누설로 실제 TDC와 차이가 발생하는 손실각(Loss of angle)을 확인하였으며, 이를 이용하여 정확한 출력을 측정할 수 있는 '향상된 시간기준' 방법을 고안하였다. 이 방법은 선박의 주기관의 손실각만 보정함으로써 엔코더가 설치된 실린더의 '각도기준 계측' 방법과 같은 결과를 얻을 수 있음을 확인하였다. 따라서 본 연구에서는 정확한 엔진출력의 새로운 계측 방법을 제시하고, 그 결과에 대한 신뢰성을 검증 하고자 한다.

• Journal of Preventive Medicine and Public Health
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• 제24권4호
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• pp.496-506
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• 1991

모 철강공장에서 1990년 8월 27일부터 9월 6일까지 실시되었던 정기 특수건강진단에 참여한 근로자 중 평균 소음노출이 $91.8{\pm}5.2dB(A)$인 고소음부서 기능직 근로자 1,034명과 $75.2{\pm}4.6dB(A)$인 저소음부서 기능직 근로자 390명 사이에 고혈압(수축기 160mmHg 이상 또는 이완기 100mmHg 이상) 유병률을 비교하고, 청력손실(1,000Hz에서 25dB 이상 또는 4,000Hz에서 40dBA이상) 여부와 고혈압 유병률과의 관계를 관찰하여 다음과 같은 결과를 얻었다. 고소음부서와 저소음부서 사이에 평균 수축기 및 이완기 혈압의 차이를 보이지 않았다(p>0.05). 고소음부서와 저소음부서 사이의 고혈압 유병률은 통계적으로 유의하지는 않았으나 39세 이내의 연령군에서는 고소음부서에서 더 높았으며, $40{\sim}49$세 사이의 연령군에서는 차이가 없었고, 50세 이상의 연령군에서는 오히려 저소음부서에서 높은 경향을 보였다. 고혈압 유병률은 고연령군에서 보다 저연령군의 청력손실군에서 정상 청력군에 비해 통계적인 유의성이 없었으나 더 높은 경향을 보였다. 청력손실, 비만도지수, 연령, 음주습관 및 고혈압 가족력이 이완기 혈압의 예견지표였다(p<0.02). 청력손실은 특히 40세 이전의 연령군에서 주요 이완기혈압 예견지표로 나타났다(p<0.01).

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.316-316
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• 2017

The objective of this study is to estimate quantitatively soil salinity and soil loss at upland soils in agriculture land region in Saemangeum reclaimed land on the south Korea coasts. Soil loss and soil salinity are the most critical problem at reclaimed tidal saline soil in Korea. The several thematic maps of research area such as land cover map, topographic and soil maps, together with tabular precipitation data used for soil erosion and soil salinity calculation. Meteorological data were measured directly as air temperature, wind speed, solar radiation, and precipitation. The experiment was conducted 2% sloped lysimeter ($5.0m{\times}20.0m$) with 14 treatments and it were separated by low salinity division (LSD) and high salinity division (HSD) install. The cation content in ground water increased during time course, but in the case of land surface water the content was variable, and $K^+$ was lower than that of $Na^+$ and $Mg^{2+}$. At the LSD under rainproof condition, the salinity was directly proportional to soil water content, but at the HSD the tendency was no reversed. In condition of rainproof, the amount of soil salinity was higher at the HSD than at the LSD. Positive correlation was obtained between the soil water content and available phosphorous content at the rainfall division, but there was no significance at the surface soil of the rainproof division. Sodium adsorption ratio and anion contents in soil were repressed in the order of vinyl-mulching > non-mulching > bare field. According to the result of analyzing soil loss, soil loss occurred in a vinyl-mulching, a non-mulching and a bare field in size order, and also approximately 11.2 ton/ha soil loss happened on the reclaimed land area. The average soil loss amount by the unit area takes place in a non-mulching and bare field a lot. Our results indicate that soluble salt control and soil erosion are critical at reclaimed tidal saline soil and the results can provide some useful information for deciding management plans to reduce soil loss and salt damage for stable crop production and diverse utilization or cultivation could be one of the management options to alleviate salt damage at reclaimed tidal saline soil in Korea.

• 터널과지하공간
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• 제27권1호
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• pp.50-57
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• 2017

본 연구는 네트워크형 복층터널의 환기설계를 위하여 분기부지점에서 발생할 수 있는 충격손실에 대한 실험연구이다. 충격손실양을 결정할 수 있는 충격손실계수는 현재까지 종횡비가 일정한 원형이나 사각단면에 관한 설계값 및 이론식만이 존재하고 있다. 하지만 현재 국내에서 검토중인 복층터널이 종횡비가 약 1:3정도로 층고가 낮은 소형차 전용도로이기 때문에 본 조건에 맞는 충격손실계수의 제시가 필요하다. 이를 위하여 Reynolds 상사법칙이 적용된 약 1:23 스케일의 실험모델을 제작하여 큰 종횡비에 따른 분기부 지점 충격손실계수를 측정하였다. 연구 결과 분기부가 존재할 때 직선구간에 작용하는 충격손실 계수 와 분기부에서 작용하는 충격손실 계수 이 선행연구 되었던 설계값 및 이론식보다 2~3배 높게 측정되는 것을 확인하였다. 즉, 큰 종횡비가 충격손실계수에 미치는 영향이 크다는 것을 확인함에 따라서 네트워크형 복층터널의 환기설계 시 보다 정확한 설계값을 제시할 수 있을 것으로 기대한다.

• ETRI Journal
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• 제42권4호
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• pp.575-584
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• 2020

Electromagnetic (EM) waves used to send signals under seawater are normally restricted to low frequencies (f) because of sudden exponential increases of attenuation (𝛼) at higher f. The mathematics of EM wave propagation in seawater demonstrate dependence on relative permeability (𝜇_r), relative permittivity (𝜀_r), conductivity (𝜎), and f of transmission. Estimation of 𝜀_r and 𝜎 based on the W. Ellison interpolation model was performed for averaged real-time data of temperature (T) and salinity (S) from 1955 to 2012 for all oceans with 41 088 latitude/longitude points and 101 depth points up to 5500 m. Estimation of parameters such as real and imaginary parts of 𝜀_r, 𝜀_r', 𝜀_r", 𝜎, loss tangent (tan 𝛿), propagation velocity (V_p), phase constant (𝛽), and α contributes to absorption loss (L_a) for seawater channels carried out by using normal distribution fit in the 3 GHz-40 GHz f range. We also estimated total path loss (L_PL) in seawater for given transmission power P_t and antenna (dipole) gain. MATLAB is the simulation tool used for analysis.

• 한국축산식품학회지
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• 제38권5호
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• pp.959-969
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• 2018

This study investigated the effects of deep freezing and storage temperature ($-50^{\circ}C$, $-60^{\circ}C$, and $-80^{\circ}C$) on the quality and freshness of lamb. To compare the qualities of deep frozen and stored lamb, fresh control and normal freezing conditions ($-18^{\circ}C$) were adopted. As quality and freshness parameters, drip loss (thawing loss and cooking loss), water-holding capacity (WHC), texture profile analysis (TPA), thiobarbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVBN) were evaluated during 5 months of storage. Temperature influenced the drip loss and WHC, and deep freezing minimized the moisture loss during frozen storage compared to the normal freezing condition. Lamb frozen and stored at deep freezing temperature showed better tenderness than that stored in normal freezing conditions. In particular, lamb frozen at lower than $-60^{\circ}C$ exhibited fresh lamb-like tenderness. Regardless of temperature, evidence of lipid oxidation was not found in any frozen lamb after 5 months, while TVBN was dependent on the applied temperature. Therefore, this study demonstrated that deep freezing could potentially be used to maintain freshness of lamb for 5 months. From the quality and economic aspects, the freezing and storage condition of $-60^{\circ}C$ is estimated as the optimum condition for frozen lamb.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.104-107
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• 2001

In order to investigate the effect of Ge addition to the Cu matrix on the microstructure and the critical current density, four kinds of internal tin processed Nb$_3$Sn strands with pure Cu and Cu 0.2, 0.4, 0.6 wt % Ge alloys were drawn to 0.8 mm diameter. The microstructure and critical current of internal tin processed Nb$_3$Sn wires that were heat treated at temperatures ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$ for 240h were investigated. The Ge addition to the matrix did not make workability worse. A Ge rich layer in the Cu-Ge matrix suppressed the growth of the Nb$_3$Sn layer and promoted grain coarsening. The greater the Ge content in the matrix, the lower the net Jc result after Nb$_3$sn reaction heat treatment. There was no significant variation in Jc observed with heat treatment temperature ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$. The values of AC loss of Ge added wires were decreased to 40 % compare with no addition wire. Low AC loss was due to segregation of Ge rich layer in the Cu-Ge matrix. If Ge added wire with thin Nb filaments were fabricated, slow diffusion rate of Sn would be overcome and decreased AC loss that is weak Point of internal tin method.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1621-1626
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• 2012

Background and objectives: Weight loss and malnutrition are common among cancer patients, these two factors greatly affecting survival and quality of life during treatment. Since cancer is becoming increasingly common in the world and in order to provide better treatment measures, it is important to identify and prevent side effects. The present study has been conducted in 2010 on a sample of cancer patients in the oncology center of Shahid Beheshti University of Medical Sciences to determine the prevalence rates of malnutrition and the factors affecting it. Methods: The PG-SGA standard questionnaire was administered to 416 cancer patients to evaluate their nutrition status and determine the frequency of each malnutrition stage. Correlations and ANOVA tests were used to analyze the relationship between factors and weight loss and how they might affect the development of malnutrition. Results: The prevalence of malnutrition among the patients was 53.1% out of which 29.1% had moderate and 24% had severe malnutrition. The most common factors inducing nutritional symptoms were depression and anorexia. Some 35 % of the patients had over 5% weight loss in the last mouth. The average PG-SGA score was 10.1 with 49 being the highest. 46.1 percent of the patients scored over 9 (requiring critical nutrient intervention). Malnutrition has a high correlation with weight loss, activity limitations, nutritional symptoms, and cancer stage, but low correlation with treatment and pathologic type. Conclusion: Malnutrition has a high prevalence in Iranian cancer patients and has a close relationship with mortality, morbidity and treatment-related problems and also quality of life. Therefore, periodical assessment by PG-SGA to detect malnutrition in patients should be made so that appropriate nutritional interventions can be provided.