• Natural Product Sciences
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• 제27권1호
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• pp.36-44
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• 2021

The essential oils from the aerial parts (leaves and flowers) of Spiraea hypericifolia L. (Rosaceae), collected in Northern Kazakhstan, were obtained by distillation in two dispersion media (distilled water and 15% NaCl solution). The chemical composition of the essential oils was evaluated by GC-MS for the first time. The yield of the essential oil was 0.04% (in fresh growth conditions) and 0.02% (in dry growth conditions) respectively regardless of which dispersion media (H2O or 15% NaCl solution) was used at the isolation of essential oil. The main compounds were aliphatic hydrocarbons (alkanes) (40.6-53.2%), aldehydes (8.4-17.4%), diterpenoids (9.1-16.7%) and ketones (6.2-8.7%). Content of monoterpenoids was depended on dispersion media (2.2-3.6% where H2O was dispersion media and 8.4-8.5% where 15% NaCl solution was dispersion media). n-Heneicosane (17.4-34.1%) and n-tricosane (14.3-19.5%) were the main constituents of the essential oil of S. hypericifolia. There were many insects from different classes in S. hypericifolia at flowering. Important components such as α-methylene-γ-butyrolactone (0.8-2.8%), benzyl cyanide (0.7-1.1%), β-damascenone (1.2-2.9%), (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (1.8-2.7%), β-ionone (0.5-1.8%) and others were detected in small amounts.

• 감성과학
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• 제25권4호
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• pp.107-118
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• 2022

Human can rapidly detect and deal with dangerous elements in their environment, and they generally manifest as attentional bias toward threat. Past studies have reported that this attentional bias is affected by anxiety level. Other studies, however, have argued that children and adolescents show attentional bias to threatening stimuli, regardless of their anxiety levels. Few studies directly have compared the two age groups in terms of attentional bias to threat, and furthermore, most previous studies have focused on attentional capture and the early stages of attention, without investigating further attentional holding by the stimuli. In this study, we investigated both attentional bias patterns (attentional capture and holding) with respect to negative emotional stimulus in neurotypical adults and adolescents. The effects of anxiety level on attentional bias were also examined. The results obtained for adult participants showed that abrupt onset of a distractor delayed attentional capture to the target, regardless of distractor type (angry or neutral faces), while it had no effect on attention holding. In adolescents, on the other hand, only the angry face distractor resulted in longer reaction time for detecting a target. Regarding anxiety, state anxiety revealed a significant positive correlation with attentional capture to a face distractor in adult participants but not in adolescents. Overall, this is the first study to investigate developmental tendencies of attentional bias to negative facial emotion in both adults and adolescents, providing novel evidence on attentional bias to threats at different ages. Our results can be applied to understanding the attentional mechanisms in people with emotion-related developmental disorders, as well as typical development.

• 한국의학물리학회지:의학물리
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• 제33권4호
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• pp.136-141
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• 2022

Purpose: This study aimed to develop a breath control training system for breath-hold technique and respiratory-gated radiation therapy wherein the patients can learn breath-hold techniques in their convenient environment. Methods: The breath control training system comprises a sensor device and software. The sensor device uses a loadcell sensor and an adjustable strap around the chest to acquire respiratory signals. The device connects via Bluetooth to a computer where the software is installed. The software visualizes the respiratory signal in near real-time with a graph. The developed system can signal patients through visual (software), auditory (buzzer), and tactile (vibrator) stimulation when breath-holding starts. A motion phantom was used to test the basic functions of the developed breath control training system. The relative standard deviation of the maxima of the emulated free breathing data was calculated. Moreover, a relative standard deviation of a breath-holding region was calculated for the simulated breath-holding data. Results: The average force of the maxima was 487.71 N, and the relative standard deviation was 4.8%, while the average force of the breath hold region was 398.5 N, and the relative standard deviation was 1.8%. The data acquired through the sensor was consistent with the motion created by the motion phantom. Conclusions: We have developed a breath control training system comprising a sensor device and software that allow patients to learn breath-hold techniques in their convenient environment.

• Macromolecular Research
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• 제12권2호
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• pp.172-177
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• 2004

We have studied the lamella-level morphology of poly(ethylene terephthalate) (PET)/polycarbonate (PC) blends using small-angle X-ray scattering (SAXS). Measurements were made as a function of the holding time in the melt. We determined the morphological parameters at the lamellar level by correlation function analysis of the SAXS data. An increased amorphous layer thickness was identified in the blend, indicating that some PC was incorporated into the interlamellar regions of PET during crystallization. The blend also exhibits a larger lamella crystalline thickness (l$\sub$c/) than that of pure PET. A possible reason for the increase in l$\sub$c/ is that the inclusion of the PC molecules in the interlamellar regions causes an increase in the surface free energy of folding. At the early stage of isothermal crystallization, we observed a rapid drop in the value of l$\sub$c/ in the blend; this finding indicates that a relatively large fraction of secondary crystals form during the primary crystallization. In contrast, the value of l$\sub$c/ for the sample that underwent a prolonged holding time increased with time in the secondary crystallization-dominant regime; this observation suggests that the disruption of chain periodicity, which results from transesterification between the two polymers, favors the development of fringed micellar crystals that have larger values of l$\sub$c/ rather than the development of normal chain-folded crystals.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.904-913
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• 2005

This paper deals with an integrated problem of inventory control and dynamic pricing strategies for a commodity with price and sales-period dependent demand pattern, where a seller and customers have complete information of each other. The problem consists of two parts; one is each buyer's benefit problem which makes the best decision on price and time for buyer to purchase items, and the other one is a seller's profit problem which decides an optimal sales strategy concerned with inventory control and discount schedule. The seller's profit function consists of sales revenue and inventory holding cost functions. The two parts are closely related into each other with some related variables, so that any existing general solution methods can not be applied. Therefore, a simplified model with single seller and two customers in considered first, where demand for multiple units is allowed to each customer within a time limit. Therewith, the model is generalized for a n-customer-classes problem. To solve the proposed n-customer-set problem, a dynamic programming algorithm is derived. In the proposed dynamic programming algorithm, an intermediate profit function is used, which is computed in case of a fixed initial inventory level and then adjusted in searching for an optimal inventory level. This leads to an optimal sales strategy for a seller, which can derive an optimal decision on both an initial inventory level and a discount schedule, in $O(n^2)$ time. This result can be used for some extended problems with a small customer set and a short selling period, including sales strategy for department stores, Dutch auction for items with heavy holding cost, open tender of materials, quantity-limited sales, and cooperative buying in the on/off markets.

• Journal of Nutrition and Health
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• 제36권10호
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• pp.1071-1082
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• 2003

The objective of this study was to evaluate and improve the microbiological quality of HACCP application in school foodservice operations. The microbiological quality of foods and utensils were evaluated two times at each critical control point (CCP) with 3M petrifilm in five Daegu elementary schools. Two processes were evaluated: Heating process and after-heating process. The CCPs of the heating process were receiving, cooking and serving temperatures. The CCPs of the after-heating process were personal hygiene, cross contamination avoidance and serving temperature. After the first experiment, 31 employees of five schools were classroom educated, trained on-site, and pre- and post-tested on HACCP-based sanitation with the goal of improving the microbiological quality of the foodservice. Scores representing knowledge of holding, thawing, washing, food temperature, sanitizing and food-borne illness increased after education. In the heating process, internal food temperatures in the first and second experiments were higher than 74$^{\circ}C$, the holding temperature in the first experiment was less than 6$0^{\circ}C$. In the second experiment, the serving temperature improved to a satisfactory level. The microbiological quality in the second experiment improved by decreasing the time from cooking to serving. In the after-heating process, the ingredients were boiled before being cut in the first experiment. In the second experiment, ingredients were cut before being boiled, improving microbiological quality. Also in the second experiment, cooking just before serving food improved its microbiological quality through time-temperature control. These results strongly suggest it is essential to measure microbiological quality regularly and to educate employees on HACCP continuously, especially time-temperature control and cross contamination avoidance in order to improve foodservice quality.

• 대한영양사협회학술지
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• 제13권4호
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• pp.389-406
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• 2007

This study was conducted to estimate the safety level of non-cooking and cooking processed foods to propose the sanitary management of foods donated to foodbanks. The time and temperature were measured and the microbial levels of aerobic plate counts (APC), coliforms, E. coli, Salmonella spp., S. aureus, B. cereus, and E. coli O157:H7 were analyzed on ten food items donated to seven foodbanks. The amount of cooked foods donated to each foodbank was about 10 to 40 servings. All foodbanks hired a supervisor and had at least one refrigerator/freezer and one temperature-controlled vehicle, but only four foodbanks had the separate offices to manage the foodbank operation. The flow of donated foods was gone through the steps; production, meal service and holding at donator, collection by foodbank, transport (or holding after transport) and distribution to recipients. After production, the levels of APC of both non-cooking and cooking processed foods were complied with the standards by Ministry of Education & Human Resources Development, and were not increased till distribution. Only the level of coliforms in dried squid & cucumber salad (1.5×$10^3$ CFU/g) was not met the standards. E. coli and other pathogens were not detected in all tested samples. The microbial levels of delivery vessels and work tables were satisfactory, but the APC levels of two of four tested serving tables (6.9×$10^3$ and 5.3×$10^3$ CFU/100$cm^2$) and the coliforms level of one (1.1×$10^3$ CFU/100$cm^2$) were over the standards. The air-borne microflora level in serving room was estimated as satisfactory. It took about 3.0 to 6.5 hours from after-production to distribution and the temperatures of donated foods were exposed mostly to temperature danger zone, which had a high potential of microbial growth. These results imply that a checklist to monitor time and temperature in each step should be provided and the employees involving foodbank operation should be properly educated to ensure the safety of donated foods.

• 열처리공학회지
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• 제5권4호
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• pp.209-214
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• 1992

7072Al 을 기지로하고 W 섬유를 강화재로 사용하여 진공 hot press 에서 복합재료를 제조한 후 시간을 변수로 열처리하여 처리시간에 다른 계변층의 변화와 이에 따른 기계적 성질의 변화를 비교 검토하였다. 각종기기(SEM, XRD 등)를 사용하여 계면층을 분석한 결과 처리시간이 10시간까지는 계면층의 변화는 미미하였으나 10시간을 초과하면서 계면층은 현저히 성장하기 시작했다. 이 계면층은 취성이 있는 $WAl_{12}$ 및 $WAl_5$의 화합물로 확인되었다. 이 화합물층의 생성은 기계적성질의 저하를 초래화고 있었다. 즉 인장강도가 처리시간이 10시간을 초과하면서 현저하게 감소하고 있었다. 또한, 파괴양상은 계면화합물층으로 인해 열처리한 후에는 열처리전의 연성파괴에서 취성파괴로 변화되었다.

• 한국화재소방학회논문지
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• 제22권1호
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• pp.84-92
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• 2008

본 연구에서는 영동지역의 대표 수종인 소나무와 떡갈나무를 대상으로 주요 부위별 열적특성을 고찰하고자 콘칼로리미터 시험을 수행하여 중량변화, 착화시간, 화염유지시간, 발열량 그리고 CO와 $CO_2$ 배출농도를 비교 분석하였다. 소나무와 떡갈나무 모두 가지의 총중량감소가 가장 크게 나타났으며, 낙엽의 착화시간이 9 s 정도로서 가장 빠르게 나타났다. 낙엽과 수피부위의 화염유지시간은 $640{\sim}1,016s$ 정도였으며, 총방출열량은 낙엽비 생엽의 2배 정도인 60.1 $MJ/m^2$로 가장 높게 나타났다. 또한, CO 및 $CO_2$의 최대 배출농도는 떡갈나무의 가지부위가 소나무의 가지보다 2.82배 이상 높게 나타남으로써 소나무와 떡갈나무의 열적특성은 부위별로 많은 차이가 있음을 확인하였다.

• 대한인간공학회지
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• 제25권4호
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• pp.93-101
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• 2006

This study examined whether there is a transfer effect to other joint angles and the angular specificity of muscle fatigue after 6 weeks of isometric training of the vastus medialis. Twenty subjects were randomly assigned to 30° and 90° knee flexion groups and were trained at 80% maximal voluntary isometric contraction(MVIC) three times a week for 6 weeks. The pre-and post-training values of the 80% holding time(endurance time) of MVIC, the Fatigue Index(FI), and the MVIC at 30°, 60°, and 90° were compared. After isometric training for 6 weeks, in the 30° knee flexion group, FI decreased significantly(p<0.05) only at 30°, which was the training angle; there was no change at other angles. By contrast, in the 90° knee flexion group, FI decreased significantly(p<0.05) at both the trained angle and at the other angles, indicating a transfer effect of training. MVIC did not increase significantly(p<0.05) at any trained angle in either the 30° or 90° knee flexion groups after 6 weeks of isometric training, neither did the 80% holding time of MVIC differ significantly compared with pre-training in either group. These findings suggest that training at 90° of knee flexion is more effective than training at 30° of knee flexion for obtaining a training transfer effect on muscle fatigue in the vastus medialis.