• Title/Summary/Keyword: Phase degree

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Structural Behavior of Mixed $LiMn_2O_4-LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ Cathode in Li-ion Cells during Electrochemical Cycling

  • Yun, Won-Seop;Lee, Sang-U
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.5-5
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    • 2011
  • The research and development of hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV) and electric vehicle (EV) are intensified due to the energy crisis and environmental concerns. In order to meet the challenging requirements of powering HEV, PHEV and EV, the current lithium battery technology needs to be significantly improved in terms of the cost, safety, power and energy density, as well as the calendar and cycle life. One new technology being developed is the utilization of composite cathode by mixing two different types of insertion compounds [e.g., spinel $LiMn_2O_4$ and layered $LiMO_2$ (M=Ni, Co, and Mn)]. Recently, some studies on mixing two different types of cathode materials to make a composite cathode have been reported, which were aimed at reducing cost and improving self-discharge. Numata et al. reported that when stored in a sealed can together with electrolyte at $80^{\circ}C$ for 10 days, the concentrations of both HF and $Mn^{2+}$ were lower in the can containing $LiMn_2O_4$ blended with $LiNi_{0.8}Co_{0.2}O_2$ than that containing $LiMn_2O_4$ only. That reports clearly showed that this blending technique can prevent the decline in capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and related structural phase transitions for these composite cathodes. In this presentation, we will report our in situ x-ray diffraction studies on this mixed composite cathode material during charge-discharge cycling. The mixed cathodes were incorporated into in situ XRD cells with a Li foil anode, a Celgard separator, and a 1M $LiPF_6$ electrolyte in a 1 : 1 EC : DMC solvent (LP 30 from EM Industries, Inc.). For in situ XRD cell, Mylar windows were used as has been described in detail elsewhere. All of these in situ XRD spectra were collected on beam line X18A at National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory using two different detectors. One is a conventional scintillation detector with data collection at 0.02 degree in two theta angle for each step. The other is a wide angle position sensitive detector (PSD). The wavelengths used were 1.1950 ${\AA}$ for the scintillation detector and 0.9999 A for the PSD. The newly installed PSD at beam line X18A of NSLS can collect XRD patterns as short as a few minutes covering $90^{\circ}$ of two theta angles simultaneously with good signal to noise ratio. It significantly reduced the data collection time for each scan, giving us a great advantage in studying the phase transition in real time. The two theta angles of all the XRD spectra presented in this paper have been recalculated and converted to corresponding angles for ${\lambda}=1.54\;{\AA}$, which is the wavelength of conventional x-ray tube source with Cu-$k{\alpha}$ radiation, for easy comparison with data in other literatures. The structural changes of the composite cathode made by mixing spinel $LiMn_2O_4$ and layered $Li-Ni_{1/3}Co_{1/3}Mn_{1/3}O_2$ in 1 : 1 wt% in both Li-half and Li-ion cells during charge/discharge are studied by in situ XRD. During the first charge up to ~5.2 V vs. $Li/Li^+$, the in situ XRD spectra for the composite cathode in the Li-half cell track the structural changes of each component. At the early stage of charge, the lithium extraction takes place in the $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component only. When the cell voltage reaches at ~4.0 V vs. $Li/Li^+$, lithium extraction from the spinel $LiMn_2O_4$ component starts and becomes the major contributor for the cell capacity due to the higher rate capability of $LiMn_2O_4$. When the voltage passed 4.3 V, the major structural changes are from the $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component, while the $LiMn_2O_4$ component is almost unchanged. In the Li-ion cell using a MCMB anode and a composite cathode cycled between 2.5 V and 4.2 V, the structural changes are dominated by the spinel $LiMn_2O_4$ component, with much less changes in the layered $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component, comparing with the Li-half cell results. These results give us valuable information about the structural changes relating to the contributions of each individual component to the cell capacity at certain charge/discharge state, which are helpful in designing and optimizing the composite cathode using spinel- and layered-type materials for Li-ion battery research. More detailed discussion will be presented at the meeting.

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C-Reactive Protein in Pregnancy and Labor (임신주령과 진통에 따른 임부 혈청 C-Reactive Protein의 동태)

  • Kim, Jong-Ho;Kim, Byung-Suk;Lee, Jae-Yul;Lee, Young-Gi;Lee, Tae-Hyung;Lee, Seung-Ho
    • Journal of Yeungnam Medical Science
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    • v.10 no.2
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    • pp.298-305
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    • 1993
  • In order to evaluate the clinical usefulness of maternal serum C-reactive protein measurement in early detection of infectious morbidity at term laboring women, serum C-reactive protein levels were measured in 521 healthy pregnant women ; 64 who were not in labor before term, 55 who were in labor before term, 71 who were not in labor at term and 331 who were in labor at term. The frequencies of elevated serum C-reactive protein level were compared in relation to the gestational weeks, the presence or absence of labor, the status of amniotic membranes and the degree of cervical dilation. The obtained results were as follows. 1. The frequencies of women with elevated serum C-reactive protein, 0.8mg/dl or higher and 2.0mg/dl or higher, in 521 health pregnant women were 12% and 4%, respectively. 2. C-reactive pretein levels of 0.8mg/dl or higher were more frequent in the group of women in labor than those not in labor(5.93%, vs. 13.73%, p<0.05), but the frequencies of C-reactive protein level of 2.0mg/dl or higher were not statistically different between both groups. The frequencies of C-reactive protein level of 0.8mg/dl or higher and 2.0mg/dl or higher were not statistically different between the groups before term and at term, intact and ruptured membranes, latent phase and active phase of labor, respectively. 3. Before term, C-reactive protein levels of 0.8mg/dl or higher and 2.0mg/dl or higher were more frequent in the group of women in labor than those not in labor(23.64 vs. 4.69, p<0.001 and 12.73% vs. 3.13%, p<0.05, respectively), but those statistical differences were not seen between both group at term. Above results and review of literature suggest that serum C-reactive protein level of 2.0mg/dl or higher may be reliable in early detection of infectious morbidity at term laboring women as well as laboring women before term, and the presence of subclinical infection should be suspected in the laboring women before term with serum C-reactive protein level of 0.8mg/dl or higher.

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Histomorphologic Change of Radiation Pneumonitis in Rat Lungs : Captopril Reduces Rat Lung Injury Induced by Irradiation (X-선 조사로 생긴 흰쥐 폐장 상해의 형태학적 변화: Captopril에 의한 폐장 상해의 경감 효과)

  • Kim, Jin-Hee
    • Radiation Oncology Journal
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    • v.17 no.3
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    • pp.238-248
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    • 1999
  • Purpose : To assess the histomorphologic changes in the rat lung injury induced by radiation, to determine whether captopril reduces the rat lung injury and to evaluate change in TNF-${\alpha}$ and TGF-${\beta}$ in rat lung damage by radiation and captopril Methods and material : Right lungs in male Sprague-Dawley rats were divided irradiation alone (10, 20, 30 Gy) or radiation (same dose with radiation alone group) with captopril (500 mg/L). Radiation alone group were sacrificed at twelve hours and eleven weeks after radiation and radiation with captopril group (captopril group) were sacrificed at eleven weeks after radiation with captopril. We examined the light microscope and electron microscopic features in the groups. Results : In radiation alone group, there were patch parenchymal collapse and consolidation at twelve hours after radiation. The increase of radiation dose shows more prominent the severity and broader the affected areas. Eleven weeks after radiation, the severity and areas of fibrosis had increased in proportion to radiation dose given in the radiation alone group. There was notable decrease of lung fibrosis in captopril group than in radiation alone group. The number of mast cells rapidly increased with increase of radiation dose in radiation alone group and the degree of increase of mast cell number and severity of collagen accumulation more decreased in captopril group than in radiation alone group. In radiation alone group, expression of TNF-${\alpha}$ and TGF-${\beta}$ increased according to increase of radiation dose at twelve hours after radiation in both group. At eleven weeks after radiation, expression of TGF-${\beta}$ increased according to increase of radiation dose in radiation group but somewhat decreased in captopril group. In the captopril group the collagen deposition increased but less dense than those of radiation alone group. The severity of perivascular thickening, capillary change, the number and degranulation of mast cells more decreased in the captopril group than in the radiation alone group. Conclusion : It is concluded that the effect of captopril in the rat lungs after radiation was considered to be due to its effect on inhibition of mast cells and reduction of collagen deposition, and captopril may be protect in lung damage after radiation. We observed expression of TNF-${\alpha}$ and TGF-${\beta}$ increased at the early phase after radiation and expression of TGF-${\beta}$ increased in proportion to increase of radiation dose at the chronic phase after radiation. This results will contribute to future investigation in reduction mechanism of captopril in lung damage after radiation.

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Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

A Study on the Effect of Startup's Innovation Orientation on Growth Aspiration (창업기업의 혁신지향성이 성장열망에 미치는 영향에 관한 연구)

  • Oh, Hyemi;Lee, Chaewon;Kim, Jinsoo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.16 no.5
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    • pp.1-14
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    • 2021
  • Innovation and Scale-up of Start-up companies are becoming important national tasks. In the past, it was spread the start-up policy paradigm such as 'Start-up America', 'Start-up Chile', 'Start-up Britain' to overcome the recession globally. However as the economic recovery has become more visible recently in advanced economies, it is shifting from a start-up support policy to a scale-up oriented policy paradigm such as 'Scale-up America', Scale-up UK', 'Scale-up Denmark'. It is necessary to enter the scale-up phase beyond the start-up phase to increase the number of high-quality jobs and to continue economic growth. Therefore, it is necessary to grow the start-up into a strong medium-sized company and to lay the foundation for survival. Therefore, the purpose of this study is to consider the antecedent factors that influence the scale-up aspiration for the start-up firm to grow into a scale-up company, and empirically identifies the differences between the stages of economic development and entrepreneurs in the country. In order to accomplish the purpose, this study predicted scale-up by aspiration which is a predictor of scale-up behavior because it is difficult to achieve visible growth in a short period of time due to the characteristics of start-up companies. In order to empirically explore these relationships, the data were collected from nascent entrepreneurs who have less than 3.5 years of the Adult Population Survey(APS) among the subjects surveyed by the Global Entrepreneurship Monitor(GEM) and the national economic development stage are divided into Innovation-driven, Efficiency-driven, Factor-driven type economies. For the test hypotheses, this study adopted the multi-level model analysis for comparison between national economic development stages and using the R 3.5.0 program. The results of this study are as follows. There is difference between the national economic development and the entrepreneur in the relationship between innovation orientation of entrepreneurs and scale-up aspirations. As the economy of the country develops, the innovation activity of the entrepreneur becomes more active. Since start-ups are heavily influenced by entrepreneurs, there is a difference in the degree of aspiration depending on how innovative an entrepreneur is in the same environment. In terms of the relationship between innovation orientation and scale-up aspiration, the fear of failure was found to differ between national economic development and entrepreneurs. The fear of failure differ from country to country, and this is one of the important factors affecting entrepreneurial activities. It is expected that the factors influencing the growth of the start-up companies which are identified through the results of these studies, will be used to create a suitable scale-up ecosystem according to the national economic development stage.

Arctic Climate Change for the Last Glacial Maximum Derived from PMIP2 Coupled Model Results (제2차 고기후 모델링 비교 프로그램 시뮬레이션 자료를 이용한 마지막 최대빙하기의 북극 기후변화 연구)

  • Kim, Seong-Joong;Woo, Eun-Jin
    • Journal of Climate Change Research
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    • v.1 no.1
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    • pp.31-50
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    • 2010
  • The Arctic climate change for the Last Glacial Maximum(LGM) occurred at 21,000 years ago (21ka) was investigated using simulation results of atmosphere-ocean coupled models from the second phase of the Paleoclimate Modelling Intercomparison Program(PMIP2). In the analysis, we used seven models, the NCAR CCSM of USA, ECHAM3-MPIOM of German Max-Planxk Institute, HadCM3M2 of UK Met Office, IPSL-CM4 of France Laplace Institute, CNRM-CM3 of France Meteorological Institute, MIROC3.2 of Japan CCSR at University of Tokyo, and FGOALS of China Institute of Atmospheric Physics. All the seven models reproduces the Arctic climate features found in the present climate at 0ka(pre-industrial time) in a reasonable degree in comparison to observations. During the LGM, the atmospheric $CO_2$ concentration and other greenhouse gases were reduced, the ice sheets were expanded over North America and northern Europe, the sea level was lowered by about 120m, and orbital parameters were slightly different. These boundary conditions were implemented to simulated LGM climate. With the implemented LGM conditions, the biggest temperature reduction by more than $24^{\circ}C$ is found over North America and northern Europe owing to ice albedo feedback and the change in lapse rate by high elevation. Besides, the expansion of ice sheets leads to the marked temperature reduction by more then $10^{\circ}C$ over the Arctic Ocean. The temperature reduction in northern winter is larger than in summer around the Arctic and the annual mean temperature is reduced by about $14^{\circ}C$. Compared to low mid-latitudes, the temperature reduction is much larger in high northern altitudes in the LGM. This results mirror the larger warming around the Artic in recent century. We could draw some information for the future under global warming from the knowledge of the LGM.

Kinematical Analysis of Heel-Brake Stop in Inline Skate (인라인 스케이트(Inline Skate) 힐 브레이크(Heel-Brake) 정지에 관한 운동학적 분석)

  • Han, Jae-Hee;Lim, Yong-Kyu
    • Korean Journal of Applied Biomechanics
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    • v.15 no.2
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    • pp.11-20
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    • 2005
  • This study has a purpose on contributing to apprehend safe and right way to stop to the inline skate beginners and to the instructors who teaches line skating on the basis for the result of the kinematical analysis on Heel brake stop movement of the inline skate, focusing on the displacement on COG, angle displacement of ankle joint, angle displacement of knee joint, angle displacement of hip joint, using a 3D image method by DLT. To achieve this goal, we analysed the kinematical factor of the 3 well-trained inline skating instructors and obtained the following results. 1. During the movement of heel-brake stop, when strong power was given to a stable and balanced stop and the lower limbs, if the physical centroid is lowered the stability increases, and if it is placed high from the base surface, as the stability decreases compared to the case of low physical centroid, we should make a stop by placing a physical centroid in the base surface and lowering the hight of physical centroid. 2. To make a stable and balanced stop and to provide a strong power to the lower limbs, it is advisable to make a stop by decreasing an angle displacement of ankle joint during a "down" movement. In case of the left ankle joint, in all events and phases the dorsiflexion angle showed a decrease. Nevertheless, in the case of the right ankle joint, the dorsiflexion angle shows an increase after a slight decrease. The dorsiflexion angle displacement of ankle joint can be diminished because of the brake pad of the rear axis frame of the right side inline skate by raising a toe, but cannot be more decreased if certain degree of an angle is made by a brake pad touching a ground surface. To provide a power to a brake pad, it is recommended to place a power by lowering a posture making the dorsiflexion angle of the left ankle joint relatively smaller than that of the right ankle. 3. To make a stable and balanced stop and to add a power to a brake pad, the power must be given to the lower limbs in lowering the hight of physical centroid. For this, it is recommended to make a down movement by decreasing the flexion angle of a knee joint and it is necessary to make a down movement by a regular decrease of the angle displacement of knee joint rather than a swift down movement in every event and phase. 4. The right angle displacement of hip joint is made by lowering vertically the hight of physical centroid as leaning slightly forward. If too narrow angle displacement of hip joint is made by leaning forward too much, the balance is lost during the stop by placing the center in front. To make a stable and balance stop and to place a strong power to the lower limbs, it is recommendable to make a narrow angle by lower the hip joint angle. However, excessive leaning of the upper body to make the angle too narrow, can cause an instable stop and loss of physical centroid. After this study, it is considered to assist the kinematical understanding during the heel brake stop movement of the inline skate, and, to present basic data in learning a method of stable and balanced stop for the inline skating beginners or for the inline skate instructors in the present situation of the complete absence of the study in inline skating.

A study on ceremonial costume and Confucianism is Chosun Dynasty - Focusing on Men's Po - (조선시대(朝鮮時代) 유교사상(儒敎思想)과 의예복연구(儀禮服硏究) - 남자(男子) 포(袍)를 중심(中心)으로 -)

  • Lee, Sun-Jae
    • Journal of the Korean Society of Costume
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    • v.16
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    • pp.221-229
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    • 1991
  • This thesis aims at reviewing the wearing aspect and formation of Chosun ceremonial dresses for meal and finding out the thought reflected by them from the standpoint that dresses themselves should be taken as one of the phenomena in culture. That is men's ceremonial costumes and confucian costumes of the royal family and the gentry family in Chosun is reviewed focused on the formation and the wearing aspect of Po, Which is a kind of them. And in the context of the phase of the times. I also considered the thoughts reflected on the clothes such as confucianism, Ying & Yang Theory, and the symbol and the thoughts of patterns in relation to the clothes. Confucian influence was the main force for the Chosun prohibitions for clothes. The major reasons for the prohibitions for clothes were as follows. First, they reflected confucian Chung myoung chooui(the principle that everything should be where it belongs). That is the prohibitions for clothes were used in the means to maintain feudalistic social order. influenced by social rank system. Second, they reflected confucian ethics in the means to recover social disciplines with the maintenance of traditional customs. This shows well in the restriction of luxurious items in dressing included the prohibitions for clothes. Third, they reflected Chosun's toadysm toward China. With the influx of Chinese style of dressing then government even changed the style of uniforms for public officials into that of Chinese resulting in dual styles of dressing. Ying & Yan Theory greatly affected the colors of Korean clothes and reflected toadysm toward China. too. The theory was embodied by prohibition of such colors for clothes as white, gray, and jade green. I reviewed the twelve patterns on Myunpok, Ten-Longivity patterns and Four-Gracious plants patterns in order to analyze the symbolism and thoughts of patterns for clothes. Nansam, Dopo, and Shimui worn by confucian scholars ensures that those clothes bears confucianism and philosopical factors. As shimui was worn by many people it appears in Chosun scholars' studies and a Chinese book called "Yeki". I reviewed the origin, procession, and ornaments of four ceremonial clothes and tried to find out the confucianism in them. First, In Kwanrei (the coming-of-age ceremony) remained ancestor worship and respect for manners. The clothes for this ceremony granted the rights and responsibilities of and adult to the wearer. The royal Kwanreipok had different dresses for each rank. As Samgapok, the crown prince wore Iksunkwan and Konryongpo for the first ritual, Wonryukwan and Kangsapo for the second, and Myunrukwan and Konpok for the third. The rank of the King's grandson was lower than the crown prince's. This example shows that Chosun people respected manners and thought the basic confucianism "God and people are equal." at the Royal court. Second, as Honreipok(wedding gown), the crown prince wore Myunrukwan and Konpok for Daereipok, Wonyukwan and Kangsapo for Napjing and Tongwoo, and Iksunkwan and Konryongpo for Chekbinui. But common people were allowed to wear an official outfit only for wedding in the means of congratulation on the most important day of their life. Wedding gowns which reflected Ying and Yang Theory emphasized the thought that union of a man and a wife is the most important event in life. Third, Sangrei(funeral) was the last ritual of a human being to send off the deceased. The mourning dresses expressed lamentation of the people left behind. Five-Dress-System for each the relative degree of familarity showed the solemnity and formality, which represented the formality of confucianism and ancestor worship. I reviewed the mourning dresses by dividing them into royal, Yangban's, and commons. They were featured by the fact that there was only one style for every walk of life. It is construed that anyone in mourning can wear the same clothes since he feels the same way regardless of his social rank. Fourth, Chereipok(sacrificial rite dresses) had different styles for each social rank. The King wore Myunpok(Kuryumyun and Kujangpok) were recorded to be worn first in the fourth year of King Taecho's ruling. The crown prince wore Palryumyun and Chiljangpok for sacrificial rite dress which was finally settled when King Sejong was in power. Common people wore Dopo, Shimui for the rite dress in the beginning of the Chosun Era and wore Dopo after Japanese invasion of Korea in 1592. In conclusion, confucianism played the main role in ceremonial dress system of Chosun and that was because it emphasized the ethics of action in life, which was different from other religions. It is true that cause-oriented thoughts and Chung myoung chooui in confucianism drove all ceremonies to extreme manners, discriminating the people who belonged to the lower social rank, and resulting in extremly luxurious life style. However, they also created a unique trend and clothes culture in the Chosun Era. I wish that this thesis provieds important information and direction for furthur studies in the future.

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The Importance of Video Fluoroscopy Swallowing Study for Nasogastric Tube Removal in Rehabilitation Patients (재활치료환자의 비위관(nasogastric tube)제거에 따른 비디오 투시연하검사(VFSS)의 중요성 평가)

  • Jung, Myoyoung;Choi, Namgil;Han, Jaebok;Song, Jongnam;Kim, Weonjin
    • Journal of the Korean Society of Radiology
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    • v.9 no.1
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    • pp.1-7
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    • 2015
  • Acute phase patients who are unconscious and are suffering from cerebral infarction, cranial nerve disorders, or cerebral apoplexy are susceptible to aspiration pneumonia due to dysphagia. In these cases, a nasogastric tube is inserted to supply nutrients. Although bedside screening tests are administered during recovery after rehabilitation, clinical examinations may not be able to ascertain asymptomatic aspiration. Therefore, a video fluoroscopy swallowing study (VFSS) was performed in 10 patients with dysphagia after rehabilitation therapy; these patients had nasogastric tubes inserted, and a rehabilitation specialist assessed the degree of swallowing based on the patients' diet and posture. If aspiration or swallowing difficulties were observed, dysphagia rehabilitation therapy was administered. The patients were reassessed approximately 30-50 days after administration of therapy, based on the patients' condition. If aspiration is not observed, the nasogastric tube was removed. A functional dysphagia scale was used to analyze the VFSS images, and the scores were statistically calculated. The mean score of patients with nasogastric tubes was $49.79{\pm}9.431$, thereby indicating aspiration risk, whereas the group without nasogastric tubes showed a mean score of $11.20{\pm}1.932$, which indicated low risk of aspiration. These results demonstrated that a significantly low score was associated with nasogastric tube removal. Mann-Whitney's test was performed to assess the significance of both the groups, and the results were statistically significant with a P value <0.001. In conclusion, VFSS can effectively assess the movements and structural abnormalities in the oral cavity, pharynx, and esophagus. It can also be used to determine the aspiration status and ascertain the appropriate diet or swallowing posture for the patient. Therefore, VFSS can potentially be used as a reliable standard test to assess swallowing in order to determine nasogastric tube removal.

Simultaneous Determination of Carbohydrates and Organic Acids in Various Cultured Dairy Foods by High-Performance Liquid Chromatography: A Preliminary Study (다양한 낙농 발효유제품에서 HPLC를 이용하여 탄수화물과 유기산의 동시 검출에 관한 연구)

  • Kim, Dong-Hyeon;Hwang, Dae-Geun;Chon, Jung-Whan;Kim, Hyunsook;Kim, Hong-Seok;Song, Kwang-Young;Yim, Jin-Hyuk;Kim, Young-Ji;Kang, Il-Byung;Lee, Soo-Kyung;Seo, Kun-Ho
    • Journal of Dairy Science and Biotechnology
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    • v.33 no.4
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    • pp.263-269
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    • 2015
  • Various carbohydrates (lactose, glucose, and fructose), lactic acid, uric acid, and acetoin were separated on a ZORBAX Carbohydrate Analysis column using the Agilent 1200 HPLC ChemStation$^{TM}$, and were identified according to retention times with 325 Dual Wavelength UV-Vis Detector and Refractive Index Detector with 0.013 N $H_2SO_4$ at a flow rate of 0.8 mL/min. In addition, the lactase activity of four commercial probiotic lactic acid bacteria during 6-hour incubation was determined using a high-performance liquid chromatography (HPLC) method. Among the tested samples, Bifidobacterium animalis subsp. lactis showed the greatest lactase activity, followed by Lactobacillus rhamnosus and Lactobacillus casei, with Streptococcus salivarius subsp. thermophilus showing the lowest activity. Therefore, this HPLC technique shows potential for evaluating the fermentation processes of probiotic lactic acid bacteria and could simultaneously confirm the degree of ripening in various fermented dairy foods within only a half hour.

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