• 한국경영과학회지
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• 제1권1호
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• pp.151-170
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• 1976

There are many cases of production processes which intermittently produce several different kinds of products for stock through one set of physical facility. In this case, an important question is what size of production run should be prduced once we do set-up for a product in order to minimize the total cost, that is, the sum of the set-up, carrying, and stock-out costs. This problem is used to be called scheduling of multiple products through a single facility in the production management field. Despite the very common occurrence of this type of production process, no one has yet devised a method for determining the optimal production schedule. The purpose of this study is to develop quantitative analytical models which can be used practically and give us rational production schedules. The study is to show improved models with application to a can-manufacturing plant. In this thesis the economic production quantity (EPQ) model was used as a basic model to develop quantitative analytical models for this scheduling problem and two cases, one with stock-out cost, the other without stock-out cost, were taken into consideration. The first analytical model was developed for the scheduling of products through a single facility. In this model we calculate No, the optimal number of production runs per year, minimizing the total annual cost above all. Next we calculate No$_{i}$ is significantly different from No, some manipulation of the schedule can be made by trial and error in order to try to fit the product into the basic (No schedule either more or less frequently as dictated by) No$_{i}$, But this trial and error schedule is thought of inefficient. The second analytical model was developed by reinterpretation by reinterpretation of the calculating process of the economic production quantity model. In this model we obtained two relationships, one of which is the relationship between optimal number of set-ups for the ith item and optimal total number of set-ups, the other is the relationship between optimal average inventory investment for the ith item and optimal total average inventory investment. From these relationships we can determine how much average inventory investment per year would be required if a rational policy based on m No set-ups per year for m products were followed and, alternatively, how many set-ups per year would be required if a rational policy were followed which required an established total average inventory inventory investment. We also learned the relationship between the number of set-ups and the average inventory investment takes the form of a hyperbola. But, there is no reason to say that the first analytical model is superior to the second analytical model. It can be said that the first model is useful for a basic production schedule. On the other hand, the second model is efficient to get an improved production schedule, in a sense of reducing the total cost. Another merit of the second model is that, unlike the first model where we have to know all the inventory costs for each product, we can obtain an improved production schedule with unknown inventory costs. The application of these quantitative analytical models to PoHang can-manufacturing plants shows this point.int.

• Journal of Nutrition and Health
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• 제30권2호
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• pp.155-169
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• 1997

This study investigated the effect of weight control by using the commercial appetite suppressant ((-)-hydroxycitric acid(HCA) formula) and nutrition education on 72 obese women over a period of 8 weeks. During the study it conducted nutritional education for women to control their weight, thus analyzed their changes in anthropometric variables. All obese women were randomized in a double-blind method to consume either HCA(HCA group : experimental group) or placebo(placebo group : control group). Two groups were also divided randomly into 2 groups combined with commercial formula diet in 1 meal a day(HD group and PD group : HCA + gormula diet and placebo + formula diet) or not(HO group and conducted with 4 groups(HD, HO, PD, and PO group). All subjects were assigned to consume 800-1500kcal/d balanced diet which is 500kcal less than their usual energy requirement. To evaluate the effect of the weight control program, weight, percent of body fat, waist and hip circumferences, and 5 skinfold thickness were measured up to 5 times in all obese women. The mean weight of the subjects at the onset of the study was 76.5$\pm$10.6kg. The mean body mass index(BMI) wa 30.1$\pm$3.8 and it was in the upper 5 percentile of mean BMI of Korean women. At the end of the program, mean weight loss was 3.5kg after 2 weeks(p<0.001), and 5.8kg after 4 weeks(p<0.001). The waist, hip ratio(WHR) and skinfold thickness measurements of biceps, triceps, subscapular, suprailiac and abdominum showed significant reduction over the entire study period(p<0.05). These outcome were evaluated by effect of nutritional education and counselling. The reduction of % of body fat was significantly different among the 4 groups. Women who administrated HCA demonstrated more change in weight, BMI than the placebo group. There was also significant reduction in body composition (% of body fat, WHR, and skinfold thickness) than the other groups. The HD group which was administrated HCA combined with formula diet was more decreased than other groups. It showed that this program using commercial HCA and formula diet induced not only a change in weight but also a change in body composition. The outcome of this study suggests that HCA has a more effctive change on weight control which is carried out with nutritional education and counselling.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.11-11
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• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.

• 한국응용곤충학회지
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• 제20권2호
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• pp.117-121
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• 1981

멸구류에 대한 품종저항성 검정법을 개발하고자 동위원소 $^{32}P$를 이용 식물체를 통하여 충체에 이행된 $^{32}P$ 방출량을 G.M. Counter로 조사하므로서 저항성 정도를 판별하기 위한 연구중 일차적으로 다음과 같은 결과를 얻었다. 가. 공시기구 개발 : 공시기구 개발을 위해 4가지 형의 기구를 공시하였는데 B,C,D형 기구는 공시법과 $^{32}P$ 용액과 분리된 시험기구로서 이중 D형이 가장 취급이 간편하며 안전하게 $^{32}P$의 흡즙량을 조사할 수 있었다(Fig. 1). 나. $^{32}P$의 적정량 : 식물체에 흡수시킬시 2Ml 까지 비슷한 경향을 보였으나 흡즙시간의 경과에 따라서 $^{32}P$용액을 식물체가 흡수하여 차츰 적은 량으로 되어 뿌리의 활력에 따라서 개체간 흡수량의 차이가 생길 우려가 있어 $2\~3ml$의 $^{32}P$용액이 요구되었다. 의. $^{32}P$의 방사능 세기 : $0.07\~7{\mu}Ci$까지는 충체에 미치는 영향이 없었으며 처리별로 각각 충분한 CPM의 방사능을 나타내었기에 $0.7{\mu}Ci$ 내외의 방사능 세기가 멸구류 검정시 효과적으로 본다. 라. 충표식방법 및 충탈피각내 잔류량 : :식물성의 흡수를 통한 표식이 효과적이었으로 충탈피각내에는 잔류량이 거의 없는 것으로 나타났다.

• 한국환경보건학회지
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• 제21권4호
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• pp.1-9
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• 1995

This study was carried to investigate the biodegradability of phenol in the wastewater with the two sludge blanket-packed bed reactor in series. Each reactor had a dimension of 0.09 m i.d. and 1.5 m height and consisted of two regions. The lower region was a sludge blanket of 0.5 m height and the upper region was a packed-bed of 1 m height. The packed bed region was charged with ceramic raschig rings of 10 mm i.d., 15 mm o.d. and 20 mm length. The reactors were operated at 35$\circ$C and the hydraulic retention time(HRT) was maintained 24 hours. The synthetic wastewater composed of glucose and phenol as major components was fed into the reactor in a continuous mode with incereasing phenol concentration. In addition, the nutrient trace metals($Na^+, Mg^{2+}, Ca^{2+}, PO_4^{3-}, NH_4^+, Co^{2+}, Fe^{2+}$ etc.) were added for growing anaerobes. The phenol concentration of the effluent, the overall gas production, the composition of product gas, the efficiency of COD reduction and the duration of acclimation period were measured to determine the performance of the anaerobic wastewater treatment system as the phenol concentration of the influent was increased from 600 to 2400 mg//l. Successfully stable biodegradation of phenol could be achieved with the anaerobic treatment system from 600 to 1, 800 mg/l of the influent phenol concentration. The upper level of influent phenol loading was high enough to meet most of the practical requirement. The duration of acclimation increased with the phenol loading. At steady state of the influent phenol concentration of 1800 mg/l, the treatment performance indicated the phenol reduction efficiency of 99%, the COD reduction efficiency of 99% and the gas production rate of 37 l/day. At the influent phenol concentration of 2400 mg/l, however, the operation of the treatment system was noted unstable. While the concentration of methane in biogas decreased with increasing the influent phenol loading, the carbon dioxide was increased. However, the concentration of hydrogen was varied negligibly. The concentration of methane was high enough to be used as a fuel. As a result, it is suggested that anaerobic phenol wastewater treament was economical in the sense of energy recovery and wastewater treatment.

• 농업과학연구
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• 제17권2호
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• pp.130-141
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• 1990

각종 식용유지에 대한 갈근 추출물의 항산화 효과를 검토하기 위하여, 수종의 유기용매를 사용하여 갈근으로 부터 항산화성 획분을 추출, 분리하여 돈지, 우지, 대두유 및 팜유에 첨가하고 $60^{\circ}C$, $100^{\circ}C$, $145^{\circ}C$에서 열처리하면서 POV, COV, TBA value 및 지방산 조성의 변화를 검토한 결과는 다음과 같다. 1. 갈근 분말을 ethanol, methanol : isopropyl al-cohol(1 : 4) 및 chloroform : methanol(95 : 5)로 항산화성 획분을 추출한 결과 얻어진 추출물의 수율은 2.5%이었다. 2. 각종 식용유지에 대하여 갈근 추출물을 0.1% 첨가하였을 때, $\alpha$-tocopherol 100ppm 첨가구 보다 다소 높은 항산화 효과를 나타내었다. 3. $60^{\circ}C$ 및 $100^{\circ}C$에서 가열처리 하였을 때 갈근추출물의 항산화 효과는 우지>팜유>돈지>대두유의 순이었다. 4. $145^{\circ}C$에서 갈근 추출물의 항산화 효과는 우지에서 미약 하였으며, 돈지, 팜유 및 대두유에 대해서는 거의 인정되지 않았다. 5. 구성 지방산중 포화 지방산 함량은 가열처리에 의하여 적게 변화하였으나 불포화 지방산의 함량은 크게 감소 하였다.

• 한국식생활문화학회지
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• 제15권2호
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• pp.139-145
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• 2000

A survey on the preference of kimchi and actual amounts of kimchi intake conducted from july to october 1999 to get basic information needed for the augmentation of kimchi intake. Total 1,241 of women and men aged $10{\sim}60$ in kyung-nam area participated in this survey. Except people aged $20{\sim}30$, all of subjects, especially in people aged 60 and over, liked fresh prepared kimchi best, and then fermented kimchi. But all of subjects disliked over fermented kimchi.(p<0.001) And women$(4.3{\pm}0.9)$ liked better fresh prepared kimchi than men$(4.2{\pm}1.0)$, men$(4.0{\pm}0.9)$ liked better fermented kimchi than women$(3.9{\pm}1.1)$.(p<0.05) In subjects aged above 40, as age grow up, the preference of fermented kimchi and over fermented kimchi grew lower. All of subjects best liked chinease cabbage kimchi, and then chonggak kimchi, kakdugi, yeulmu kimchi, dongchimi in order. And women liked better nabag kimchi, yeulmu kimchi, sesame leaf kimchi, bek kimchi, cucumber kimchi, godulppegi kimchi than men and men liked better chinease cabbage kimchi, kakdugi, dongchimi than women.(p<0.05) People aged $10{\sim}20$ and above 60 disliked chonggag kimchi. The preference of kakdugi were high in people aged $10{\sim}20$, but as age grow up, the preference of kakdugi became lower.(p<0.001) The preference of nabak kimchi and dongchimi with juice were significantly high in people aged 60 and over but people aged $10{\sim}20$ disliked. Also subjects aged $10{\sim}20$ disliked significantly yeulmu kimchi, sesame leaf kimchi, green onion kimchi, bek kimchi, cucumber kimchi, mustard leaf kimchi and godulppegi kimchi and subjects aged $20{\sim}30$ disliked significantly yeulmu kimchi, mustard leaf kimchi, godulppegi kimchi(p<0.001). But subject aged 30 and older liked all kinds of kimchi. The amounts of kimchi intake in Kyung-nam area were same level of average amount(100g) of korean intake but the amounts of kimchi intake of men$(106.4{\pm}74.0)$ were more than women$(96.9{\pm}69.5)$(p<0.05)

• 한국식품과학회지
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• 제36권1호
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• pp.14-18
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• 2004

본 연구는 인공감미료의 사용확대에 따른 실태 파악 및 실제 섭취량 조사를 통해 현행 사용기준의 안전수준에 대한 안전성을 확보하는 연구의 기초자료로서 우리나라에서 식품첨가물로 허용되어 있는 인공감미료인 삭카린나트륨, 아스파탐, 아세설팜칼륨 및 수크랄로스에 대한 식품 중 분석법을 확립하였으며 결과는 다음과 같다. 먼저 투석이나 정제과정 없이 보다 간편하고 짧은 시간에 효율적으로 시료를 전처리할 수 있는 방법을 시료의 성상에 따라 확립하였다. 고속액체크로마토그래프(HPLC)의 최적 분석조건을 검토한 결과, 삭카린나트륨, 아스파탐 및 아세설팜칼륨의 3종 인공감미료의 분석에 컬럼은 Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$, 이동상은 0.005M tetrapropylammonium hydroxide가 함유된 0.01M $KH_{2}PO_{4}$: acetonitrile(9:1, pH 3.5). 측정파장은 210mm로 설정하였다. 수크랄로스의 분석조건은 컬럼은 Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$, 이동상은 water: methanol(7:3)을 사용하였고 검출기는 굴절율 검출기(RI), sensitivity=16호 설정하였다. 검출한계는 삭카린나트륨, 아스파탐 및 아세설팜칼륨은 각각 0.1ppm, 수크랄로스는 25ppm으로 측정되었다. 이와 같이 결정된 인공감미료의 최적 분석조건으로 회수율을 측정한 결과 아스파탐 92.5%, 아세설팜칼륨 97.3%, 삭카린나트륨 96.5%, 수크랄로스 93.4%로 양호한 결과를 얻었다. 시중에서 유통되고 있는 제품 중 총 17종 151품목을 다상으로 4종의 인공감미료 함량을 정량한 결과, 아스파탐은 탄산음료 2품목에서 $180.8{\mu}g/g$, 발효음료 4품목에서 $65.3{\mu}g/g$, 껌 2품목에서 $232.5{\mu}g/g$, 사탕 1품목에서 $1,672.0{\mu}g/g$, 혼합제제식품첨가물 2품목에서 $5,259.0{\mu}g/g$이 검출되었으며 아세설팜칼륨은 탄산음료 2품목에서 $110.8{\mu}g/g$, 껌 3품목에서 $250.3{\mu}g/g$, 혼합제제식품첨가물 1품목에서 $2,362.1{\mu}g/g$, 삭카린나트륨은 어묵 1품목에서 $42.3{\mu}g/g$, 수크랄로스는 껌 1품목에서 $120.1{\mu}g/g$이 검출되었으며 검출된 인공감미료는 표시사항과 일치하였다.

• 한국환경생태학회지
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• 제30권6호
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• pp.986-995
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• 2016

본 연구에서는 금강 대권역에 서식하는 멸종위기 담수어류의 분포, 이들 종에 대한 화학적 지표와의 관계 및 물리적 서식지 특성을 분석하였다. 금강 대권역에 서식하는 멸종위기종의 개체수는 감돌고기(Pseudopungtungia nigra), 꾸구리(Gobiobotia macrocephala), 돌상어(Gobiobotia brevibarba), 퉁사리(Liobagrus obesus), 미호종개(Iksookimia choii) 순으로 나타났다. 멸종위기 야생생물 I급 어류인 감돌고기는 금강 대권역 내 18개 하천에서 가장 광범위하게 분포하여, 향후 감돌고기의 I급 어종 선정에 대한 재평가가 필요한 것으로 사료되었다. 또한 초강 중권역에서 멸종위기어종이 총 4종 384개체가 채집되어 종수 및 개체수가 풍부하였다. 멸종위기어종 서식지에서 이화학적 수질내성도 분석에 따르면, 생물학적 산소요구량(BOD) 및 총인(TP)은 각각 매우 좋음(Ia), 좋음(Ib)으로 평가 되었으며. 암모니아성 질소($NH_{4+}$), 총질소(TN), 인산염 인($PO_{4^-}P$) 등의 수질 항목도 멸종위기종 비 출현지점에 비해 훨씬 양호한 것으로 분석되었다. 한편, 미호종개의 경우 수질의 내성범위가 다른 어종에 비해서 광범위하게 나타나, 화학적 수질특성이 크게 악화되지 않을 경우 수질특성 보다는 미소서식처의 하상구조, 수리수문학적 특성 등의 물리적 서식지 조건이 더 중요한 것으로 나타났다. 또한, 멸종위기종의 분포는 1~3차의 소형하천보다 4~6차 대형하천에서 높게 나타났으며, 주로하천의 상류 및 중상류에 작은 무리를 이루며 서식하는 것으로 나타났다. 멸종위기종 미출현지역과 출현지역의 생태건강도 다변수 평가모델 값은 각각 21.6 "보통상태(Fair)" 및 30.5 "양호상태(Good)"로 나타나 뚜렷한 차이를 보여, 생태건강도가 잘 유지된 곳에서 멸종위기종이 잘 서식하는 것으로 나타났다. 본 연구를 요약해 보면, 감돌고기와 같은 어종의 멸종위기종 선정에 대한 재평가가 향후 필요하며, 수질오염 및 서식지교란이 가속화되고 있어 멸종위기종에 대한 체계적인 보호 및 관리가 필요하다.

• 한국축산시설환경학회지
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• 제11권3로
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• pp.207-214
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• 2005

축산폐수에서 용해인과 암모니아 질소를 제거하기 위하여 마그네슘을 첨가하여 시험을 수행하였다. 자돈사의 축산폐수를 대상으로 실험을 하였을 때 원수의 용해인의 수치가 폭기구에서 $471mg/\ell$, NaOH로 pH를 조정하여 준 구에서 $559mg/\ell$ 이었으며, 각기 $5mg/\ell$와 $4mg/\ell$으로 감소하여 공히 $99\%$의 제거효율을 나타내었다 특히, 실험온도가 $6-8^{\circ}C$를 유지하였는데에도 양호한 효과를 나타내어서 겨울철 낮은 온도에서도 작동이 가능할 것으로 판단되었다. 암모니아 질소의 제거효율은 폭기구에서 $15\%$, NaOH로 pH를 조절해준 구에서 $18\%$를 나타내었다. pH를 NaOH로 조정해준 구와 폭기를 시켜준 구의 비교에서 폭기만 시켜주어도 pH가 8.4 정도로 되어 pH 조정구와 유사한 제거 효과를 얻을 수 있었다. Struvite 결정체의 관찰에서 직사각형 형태의 결정체와 결정체가 서로 결합한 모양을 볼 수 있었다. 마그네슘과 인을 동시에 주입하여 암모니아 질소의 제거효율을 높이고자 한 실험에서 용해인은 인을 2g 넣은 구에서는 $99\%$로 거의 제거되었으나 4g 넣은 구에서는 절대량으로 보아서는 제거량이 많으나 효율면에서는 $15\~19\%$로 그리 높지 알았다. 암모니아 질소의 제거율도 각각 $18\%,\;15\%$로 앞선 실험의 결과와 유사하였고 향상되지 않아 반응기작에 관한 분석이 더 필요한 것으로 사료된다.