• Food Science and Preservation
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• v.23 no.1
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• pp.131-138
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• 2016

This study was conducted to investigate the change in the quality of early season Fuji apples that were subjected to eight different storage conditions using the developed controlled atmosphere (CA) storage system. Early season Fuji apples grown at Mungyeong, in the South Korea, were harvested in September 2014 for storage studies. Flesh firmness, titratable acidity, total soluble solid content, weight loss, and internal browning disorder were used as quality indicators for the stored apples. Flesh firmness and weight loss were better than that of the control after 70 days of storage. However, there was no significant difference in the titratable acidity or total soluble solid content among the apple samples from eight chambers after storage. The internal browning disorder of apple samples in CA chambers occurred when exposed to 1% $CO_2+2%$ $O_2$ and 1% $CO_2+0.5%$ $O_2$, resulting in a higher incidence rate of 2 and 8% after 70 days of storage than that in the control. In addition, the CA storage conditions at 3, 4 and 5% $CO_2+2%$ $O_2$ increased the rate of internal browning disorder by 26%. Therefore, CA storage can be used to maintain the quality of the apple if the optimal gas concentrations in the CA are applied to the storage strategy.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.45-47
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• 2002

반도체 소자의 고집적화 및 고속화가 요구됨에 따라 MOSFET 구조의 게이트 절연막으로 사용되고 있는 SiO₂ 박막의 두께를 감소시키려는 노력이 이루어지고 있다. 0.1㎛ 이하의 소자를 위해서는 15Å 이하의 두께를 갖는 SiO₂가 요구된다. 하지만 두께감소는 절연체의 두께와 지수적인 관계가 있는 누설전류를 증가시킨다[1-3]. 따라서 같은 게이트 개패시턴스를 유지하면서 누설전류를 감소시키기 위해서는 높은 유전상수를 갖는 두꺼운 박막이 요구되는 것이다. 그러므로 약 25정도의 높은 유전상수를 갖고 5.2～7.8 eV 정도의 비교적 높은 bandgap을 갖으며, 실리콘과 열역학적으로 안정한 물질로 알려진 HfO2[4-5]가 최근 큰 관심을 끌고 있다. 본 연구에서는 HfO₂ 박막을 실제 소자에 적용하기 위하여 전극 및 열처리에 따른 HfO₂ 박막의 미세구조 및 전기적 특성에 관한 연구를 수행하였다. 이를 위해, HfO₂ 박막을 reactive DC magnetron sputtering 방법으로 증착하고, XRD, TEM, XPS를 사용하여 ZrO₂ 박막의 미세구조를 관찰하였으며, MOS 캐패시터 구조의 C-V 및 I-V 특성을 측정하여 HfO₂ 박막의 전기적 특성을 관찰하였다. HfO₂ 타겟을 스퍼터링하면 Ar 스퍼터링에 의해 에너지를 가진 산소가 기판에 스퍼터링되어 Si 기판과 반응하기 때문에 HfO₂ 박막 형성과 더불어 Si 기판이 산화된다[6]. 그래서 HfO₂같은 금속 산화물 타겟 대신에 순수 금속인 Hf 타겟을 사용하고 반응성 기체로 O₂를 유입시켜 타겟이나 시편위에서 high-k 산화물을 만들면 SiO/sub X/ 계면층을 제어할 수 있다. 이때 저유전율을 갖는 계면층은 증착과 열처리 과정에서 형성되고 특히 500℃ 이상에서 high-k/Si를 열처리하면 계면 SiO₂층은 증가하는 데, 이것은 산소가 HfO₂의 high-k 박막층을 뚫고 확산하여 Si 기판을 급속히 산화시키기 때문이다. 본 방법은 증착에 앞서 Si 표면을 희석된 HF를 이용해 자연 산화막과 오염원을 제거한 후 Hf 금속층과 HfO₂ 박막을 직류 스퍼터링으로 증착하였다. 우선 Hf 긍속층이 Ar 가스 만의 분위기에서 증착되고 난 후 공기중에 노출되지 않고 연속으로 Ar/O₂ 가스 혼합 분위기에서 반응 스퍼터링 방법으로 HfO₂를 형성하였다. 일반적으로 Si 기판의 표면 위에 자연적으로 생기는 비정질 자연 산화막의 두께는 10～15Å이다. 그러나 Hf을 증착한 후 단면 TEM으로 HfO₂/Si 계면을 관찰하면 자연 산화막이 Hf 환원으로 제거되기 때문에 비정질 SiO₂ 층은 관찰되지 않았다. 본 실험에서는 HfO2의 두께를 고정하고 Hf층의 두께를 변수로 한 게이트 stack의 물리적 특성을 살펴보았다. 선증착되는 Hf 금속층을 0, 10, 25Å의 두께 (TEM 기준으로 한 실제 물리적 두께) 로 증착시키고 미세구조를 관찰하였다. Fig. 1(a)에서 볼 수 있듯이 Hf 금속층의 두께가 0Å일때 13Å의 HfO₂를 반응성 스퍼터링 방법으로 증착하면 HfO₂와 Si 기판 사이에는 25Å의 계면층이 생기며, 이것은 Ar/O₂의 혼합 분위기에서의 스퍼터링으로 인한 Si-rich 산화막 또는 SiO₂ 박막일 것이다. Hf 금속층의 두께를 증가시키면 계면층의 성장은 억제되는데 25Å의 Hf 금속을 증착시키면 HfO₂ 계면층은 10Å미만으로 관찰된다. 그러므로 Hf 금속층이 충분히 얇으면 플라즈마내 산소 라디칼, 이온, 그리고 분자가 HfO₂ 층을 뚫고 Si 기판으로 확산되어 SiO₂의 계면층을 성장시키고 Hf 금속층이 두꺼우면 SiO/sub X/ 계면층을 환원시키면서 Si 기판으로의 산소의 확산은 막기 때문에 계면층의 성장은 억제된다. 따라서 HfO₂/Hf(Variable)/Si 계에서 HfO₂ 박막이 Si 기판위에 직접 증착되면, 순수 HfO₂ 박막의 두께보다 높은 CET값을 보이고 Hf 금속층의 두께를 증가시키면 CET는 급격하게 감소한다. 그러므로 HfO₂/Hf 박막의 유효 유전율은 단순 반응성 스퍼터링에 의해 형성된 HfO₂ 박막의 유전율보다 크다. Fig. 2에서 볼 수 있듯이 Hf 금속층이 너무 얇으면 계면층의 두께가 두꺼워 지고 Hf 금속층이 두꺼우면 HfO₂층의 물리적 두께가 두꺼워지므로 CET나 EOT 곡선은 U자 형태를 그린다. Fig. 3에서 Hf 10초 (THf=25Å) 에서 정전 용량이 최대가 되고 CET가 20Å 이상일 때는 high-k 두께를 제어해야 하지만 20Å 미만의 두께를 유지하려면 계면층의 두께를 제어해야 한다.

• Journal of Life Science
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• v.24 no.3
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• pp.242-251
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• 2014

The objective of this study was to isolate a photosensitizer from Pueraria thunbergiana leaves that induces apoptosis in SK-HEP-1 cells. Column chromatography and thin layer chromatography were used to isolate active compounds from extracts of P. thunbergiana leaves. The structures of the isolated compounds were determined by 1D-NMR, 2D-NMR, and FAB-mass spectroscopy. A substance, named M4-3, was purified from the leaves of P. thunbergiana using various chromatography methods, and the absorbance of the substance was measured. The absorbance was highest at 410 nm, suggesting that the M4-3 substance was a different compound from chlorophyll a and b, which absorb at 410, 502, 533, and 607 nm. Further analyses revealed that the M4-3 compound was a $13^2$-hydoxy pheophorbide, a methyl ester with a molecular weight of 662. M4-3 was identified as a derivative compound of pheophorbide, with a structure that magnesium comes away from the porphyrin ring. The results of the analysis of the cytotoxicity of the M4-3 substance against the SK-HEP-1 cells revealed that it inhibited rates of cell growth by 40% and 80% at a concentration of 0.04 ${\mu}M$ and 0.08 ${\mu}M$, respectively. The M4-3 compound was found to be a photosensitizer for cytotoxicity because it was appeared only in light condition as examining activity in different irradiation conditions (light condition and nonlight condition) under the same concentration. Analysis of morphological changes in the cells following cell death induced by exposure to the M4-3 substance reveled representative phenomena of apoptosis (nuclear condensation, vesicle formation, and fragmentation of DNA). The induction of apoptosis was attributed to the compound's photodynamic activity.

• Education of Primary School Mathematics
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• v.10 no.1 s.19
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• pp.41-56
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• 2007

Related with the mathematics gifted children the situation of different case studies is the research which is limited in mathematics problem solving process of the most mathematics gifted children. The research which it sees hereupon observes from the scope which is wider the quality of the mathematics gifted children, before the hazard mathematics gifted children whom it sees enter into the mathematics gifted children education center unit life and life after studying living and dismissal of a class from the general school, namely for their general life it leads compared to attitude it observes the reporter it does a quality. For a what kind of interest in the mathematics gifted children, the research leads the family or general class, from the gifted children education center it has it considers encouragement, map and to give a help to good mathematics gifted children education activation, it does. It will reach and to respect with afterwards it set a same three research problem. First, before entering into the mathematics gifted children education center, are the mathematics gifted children what kind of quality? Second, Are the mathematics gifted children what kind of quality for general school hour? Third, Are the mathematics gifted children what kind of quality after dismissal of a class after hour? Being selected in the hazard gifted children education center which solves an up research problem, simple characteristic and approach ease characteristic, by the condition of the permission possibility back it selected 2 person gifted children school boxes which are coming and going. And, before entering into these mathematics gifted children education center, studying life from the general school, life after dismissal of a class it will extend at 1 years, various recording it will ask and it collected direct observation and interview it led against their quality it analyzed. It shared the result which it analyzes with emotional quality, studying conduct qualities, general qualities of the mathematics gifted children and qualities of mathematics gifted children parents. Studies level of the mathematics gifted children parents high facility when them are young from, the interest and helping out which it has were considerable, to advance with the direction where in order for always with great disaster them are proper the map it did. In general quality of the mathematics gifted children from young age the ability which finds a language and a possibility concept superiorly the ability which expresses the thought of oneself logically was superior, the competitive spirit was high, it liked it came reading, a leader role, to reveal a deepening school with the fact that it comes and goes. Also it will burn with their studying conduct quality and it will roll and it did deeply and it arranged knot eagerly, accomplishing which is superior from the field which is various it showed, the originality was superior, the subject attachment power was high quite, oneself it studies it has a devotion the possibility of knowing it was. And, the social characteristic of the friends and is good with their emotional quality and it does there is own reflection and an encouragement at any time and also a confidence, but just as good as the stress also it receives the possibility of knowing it was to him.

• Korean journal of food and cookery science
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• v.22 no.6 s.96
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• pp.914-922
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• 2006

Korean traditional rice wines and liquors have been long brewed using nuruk or koji, cooked rice, How, yeast and some medicinal plants or herbs. The rosemary shrub (Rosmarinus officinalis L), belonging to the Labiatae family, is well recognized for its aromatic, antioxidant, antimicrobial and antitumoral properties. In this study, we investigated the effect of rosemary addition on the quality characteristics of Korean traditional rice wine. Wines containing different rosemary concentrations (0, 10, 20 or 30%) were ripened for 0, 5, 10, 15 and 20 days at 25C. The following quality characteristics were compared: pH, total acid, titratable acidity, amylase activity, color, reducing sugar amount, total sugar and ethanol. Although total acid increased, the pH of rosemary wine rapidly decreased during the rot 5-days of ripening, and these two changes were greatest in the wine containing 10% rosemary. The amount of both reducing sugar and ethanol in the wine rapidly increased during the rot 5-days of ripening, while total sugar content of rosemary wine decreased significantly with increasing ripening periods(p<0.05). According to the Hunter's color results, a significant color change in 'L' value was observed with increasing fermentation period in the wine containing 10% rosemary. Although 'a' value of control (0% rosemary liquor) increased during the ripening period, the addition of rosemary did not significantly affect 'a' or 'b' values. The transmittance of rosemary wines increased with increasing rosemary content but decreased throughout the ripening periods. Amylase activity decreased with increasing rosemary content, especially after a 5-day ripening period.

• Herbal Formula Science
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• v.22 no.2
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• pp.63-76
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• 2014

Objectives : This study investigated the improvement effects of Pakistani (DF-a) and Chinese Ephedra herba-containing Gangjihwan (DF-b) on obesity in a high fat diet-fed obese mouse model. Methods : Eight-week-old C57BL/6N mice were divided into four groups: a normal lean group given a standard diet, an obese control group given a high fat diet, and DF-a and DF-b groups given a high fat diet with DF-a (80 mg/kg), and DF-b (80 mg/kg), respectively. After 8 weeks of treatment, body weight gain, feeding efficiency ratio, blood lipid markers, fat weight and histology were examined. Results : 1. Body weight gain and fat mass were significantly decreased in DF-a and DF-b groups compared with control. The extent of decreases was eminent in DF-a group. 2. Feeding efficiency ratio and circulating leptin concentration were significantly decreased in DF-a and DF-b groups compared with control, whereas circulating adiponectin concentration was increased in DF-a and DF-b groups compared with control. 3. Consistent with their effects on body weight gain and fat mass, circulating concentrations of triglyceride, glucose and insulin were decreased in DF-a and DF-b groups compared with control. 4. The size of adipocytes were decreased by DF-a and DF-b compared with control, whereas the adipocyte number per unit area was increased by them, suggesting that DF-a and DF-b decreased the number of large adipocytes. 5. Consistent with their effects on body weight gain, liver fibrosis was reduced in DF-a and DF-b groups compared with control. Conclusions : In conclusion, these results suggest that DF-a and DF-b not only decrease feeding efficiency ratio, plasma leptin concentration, and blood anti-obesity biomarkers, but also reduce fat mass, contributing to the improvement of obesity. DF-a and DF-b also inhibit liver fibrosis. In addition, these effects were similar between Pakistani Ephedra herba and Chinese Ephedra herba-containing Gangjihwan.

• Herbal Formula Science
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• v.22 no.2
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• pp.105-120
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• 2014

Objectives : This study was investigated the improvement effects of Gangjihwan (DF) and combination of Gangjihwan and Gamisochehwan (GSH) on obesity in a high fat diet-fed obese mouse model. Methods : Eight-week-old C57BL/6N mice were divided into four groups: a normal lean group given a standard diet, an obese control group given a high fat diet, and DF and DF+GSH groups given a high fat diet with DF (40 mg/kg), and DF+GSH (80 mg/kg), respectively. After 8 weeks of treatment, body weight gain, feeding efficiency ratio, blood lipid markers, fat weight and histology were examined. Results : 1. Body weight gain and fat mass were significantly decreased in DF and DF+GSH groups compared with control. The extent of decreases was eminent in DF+GSH group. 2. Feeding efficiency ratio and circulating concentration of leptin were decreased in DF and DF+GSH groups compared with control. These decreases were significant in DF+GSH group. 3. Consistent with their effects on body weight gain and fat mass, circulating concentrations of triglyceride, glucose and insulin were decreased in DF and DF+GSH groups compared with control. 4. The size of adipocytes was decreased by DF and DF+GSH compared with control, whereas the adipocyte number per unit area was increased by them, suggesting that DF and DF+GSH decreased the number of large adipocytes. 5. Consistent with their effects on body weight gain, liver fibrosis was also improved in DF and DF+GSH groups compared with control. Conclusions : In conclusion, these results suggest that DF and DF+GSH groups decrease feeding efficiency ratio, plasma leptin concentration, blood anti-obesity biomarkers and fat mass, improves body weight gain contributing to the inhibition of liver fibrosis. In addition, these effects were more effective in DF+GSH combination group than in DF-only group.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.3
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• pp.108-118
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• 2012

To investigate the responses of yellow poplar (Liriodendron tulipifera L.) seedlings to the interactive effects of the elevated atmospheric $CO_2$ level and nitrogen addition, we measured biomass, photosynthetic pigments, photosynthesis, and the contents of nitrogen (N) and carbon (C) from the seedlings after 16 weeks of the treatments. Yellow poplar seedlings were grown under the ambient ($400{\mu}mol\;mol^{-1}$) and the elevated (560 and $720{\mu}mol\;mol^{-1}$) CO2 concentratoins with three different N addition levels (1.2, 2.4, and $3.6g\;kg^{-1}$) in the Open Top Chambers (OTC). The dry weight of the seedlings enhanced with the increased N levels under the elevated $CO_2$ concentrations and the increment of the dry weight differed among the different N levels. Photosynthetic pigment content of the yellow poplar leaves also increased with the increase of the $CO_2$ concentration levels. The effects of the N levels on the photosynthetic pigment content, however, were significantly different among the $CO_2$ levels. Photosynthetic rates were affected by the levels of $CO_2$ and N concentrations. Stomatal conductance and transpiration rates increased with increasing $CO_2$ concentration. The carboxylation efficiency of the seedlings without N addition increased under the higher $CO_2$ concentrations whereas that with N addition decreased under the elevated $CO_2$ concentrations. Nitrogen and carbon uptake in leaf, stem, and root increased with the elevated $CO_2$ concentration level and N addition. In conclusion, under the elevated $CO_2$ concentrations, physiological characteristics and carbon uptake of the yellow poplar seedling were improved and increased with N addition.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.1
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• pp.31-38
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• 2008

Ad-Hoc network is a network architecture which has no backbone network and is deployed temporarily and rapidly in emergency or war without fixed mobile infrastructures. All communications between network entities are carried in ad-hoc networks over the wireless medium. Due to the radio communications being extremely vulnerable to propagation impairments, connectivity between network nodes is not guaranteed. Therefore, many new algorithms have been studied recently. This study proposes the secondary header approach to the cluster based routing protocol (CBRP). The primary header becomes abnormal status so that the primary header can not participate in the communications between network entities, the secondary header immediately replaces the primary header without selecting process of the new primary header. This improves the routing interruption problem that occurs when a header is moving out from a cluster or in the abnormal status. The performances of proposed algorithm ACBRP(Advanced Cluster Based Routing Protocol) are compared with CBRP. The cost of the primary header reelection of ACBRP is simulated. And results are presented in order to show the effectiveness of the algorithm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.2
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• pp.295-301
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• 2003

This study was carried out to investigate perception about body image, dietary attitude, nutrient intake and dietary self-efficacy of high school students in Pusan. A questionaire survey was distributed among 491 high school students. The survey was conducted from April 8 to April 22 in 2002. The results are summarized as follows. Forty percents of the underweight group, 53.9% of the normal weight group, 61.8% of the overweight group and 48.2% of obesity group have correct perception about their body image. Most of the students were concerned with their body image and weight control. Obesity of parents was significantly correlated with obesity of the subjects (p<0.01). The higher obesity rate, the lower dietary self-efficacy. The higher dietary self-efficacy, the higher dietary attitude. There was a significant positive correlation between the education level of their parents and dietary attitude of the subjects (p<0.01) and a significant negative correlation between obesity rate of their mothers and dietary attitude of the subjects (p<0.01). Dietary attitude scores showed no significant difference among the groups. Intakes of most nutrients, except protein, niacin and vitamin C, were lower than those of the recommended dietary allowances for Koreans. Therefore, proper nutrition education is required to improve their nutritional status and dietary self-efficacy.