• 한국생산제조학회지
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• 제20권5호
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• pp.541-546
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• 2011

This study was numerically investigated on thermal deformation of AC4C and AC7A aluminum alloy casting material for manufacturing the automobile tire mold. The metal casting device was used in order to manufacture the mold product of automobile tire at the actual industrial field. The temperature distribution and the cooling time of these materials were numerically calculated by finite element analysis. Thermal deformation with stress distribution was also calculated form the temperature distribution results. The thermal deformation was closely related to the temperature difference between the surface and inside of the casting. As shown by numerical analysis result, the thermal deformation of AC7A casting material became higher than AC4C casting material. In addition, the results of displacement and stress distributions appeared to be larger at the center parts of casting than on its sides because of the shrinkage caused by the cooling speed difference.

• 동아시아식생활학회지
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• 제20권4호
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• pp.543-550
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• 2010

칡에서 추출한 이소플라본(AI)의 첨가량을 0, 1.76, 3.52 및 7.11 g/kg으로 각각 달리하여 제조한 청국장(Con, AC1, AC2, AC3)의 품질 특성 및 이소플라본의 함량을 조사하여, 칡 이소플라본 첨가 청국장의 건강기능성 식품으로서의 이용 가능성을 알아보았다. AI 첨가량이 증가할수록 청국장의 pH는 낮아졌고, 점질물의 함량은 4.46~7.36%로 대조구(4.36%)에 비해 높아졌으나, 일반 성분 함량은 차이가 없었다. 청국장의 색도는 AI 첨가량이 증가할수록 $L^*$, $a^*$ 및 $b^*$ 값 모두 낮아져 전체적으로 옅은 초록색을 나타냈다. 칼슘 함량은 AI 첨가구(AC1, AC2, AC3)가 대조구에 비해 11.18~12.82% 증가하였다. 청국장의 이소플라본 함량은 AI 첨가량의 증가에 따라 AC3>AC2>AC1 순으로 유의적으로 증가하여, 대조구에 비해 30.81~130.66% 증가하였다. Aglycone 형태인 genistein과 daidzein은 AI 첨가구(AC1, AC2 및 AC3)가 대조구에 비해 각각 65.00~128.34%와 89.38~142.91% 증가하였으며, glycoside 형태의 genistin과 daidzin 역시 AI 첨가량의 증가에 따라 그 함량이 증가하였다. 이상의 결과, 칡 이소플라본을 첨가하여 제조한 청국장은 일반 청국장에 비해 이소플라본의 함량이 높을 뿐만 아니라 특히, 체내 이용 효율이 높은 aglycone 형태의 이소플라본을 높게 함유하고 있으므로 건강기능성 식품 개발에 활용할 수 있을 것으로 사료된다.

• 수산해양교육연구
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• 제23권1호
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• pp.67-74
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• 2011

The study was constructed an analysis of postures of a expert diver's wearing and taking off with skinscuba equipment using ergonomics tools(REBA, RULA, OWAS) for prevention of Musculoskeletal injuries. This survey is consisted of 4 postures in terms of wearing and taking off : Crouching(alone), Standing(alone), Helping of assistance, Using of stanchion. Their rate of injuries is getting higher due to instability postures, exposed dangers and excessive physical actions. So this study provides basic and educational information for prevention of that. The result is as follows : The result of crouching postures of wearing alone was REBA 9(Ac Level 3), RULA 7(Ac Level 4), OWAS AC 2, and crouching postures of taking off alone was REBA 12(Ac Level 4), RULA 7(Ac Level 4), OWAS AC 4. The result of standing postures of wearing alone was REBA 8(Ac Level 3), RULA 7(Ac Level 4), OWAS AC 3, and standing postures of taking off alone was REBA 8(Ac Level 3), RULA 7(Ac Level 4), OWAS AC 3. The result of helping of assistance postures of wearing was REBA 4(Ac Level 2), RULA 3(Ac Level 2), OWAS AC 2, and standing postures of taking off alone was REBA 4(Ac Level 2), RULA 4(Ac Level 2), OWAS AC 1. The result of using of stanchion postures of wearing was REBA 3(Ac Level 1), RULA 3(Ac Level 2), OWAS AC 1, and standing postures of taking off alone was REBA 3(Ac Level 1), RULA 3(Ac Level 2), OWAS AC 1. Especially both postures of wearing and taking off alone showed high results in the analysis of postures using ergonomics tools(REBA, RULA, OWAS).

• Korean Journal of Ophthalmology
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• 제32권6호
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• pp.483-487
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• 2018

Purpose: To compare the characteristics and surgical outcomes in patients with tenacious proximal fusion (TPF) and high accommodative convergence/accommodation ratio (AC/A) types of intermittent exotropia. Methods: This study retrospectively enrolled 40 patients with intermittent exotropia, 23 with TPF and 17 with high AC/A. Binocular function was evaluated by Worth's 4-dot test. Patients underwent lateral rectus recession, and surgical outcomes were compared. Surgical success was defined as less than ${\pm}10$ prism diopters (PD) at 12 months postoperatively. Results: The proportion of diplopia at near, evaluated by Worth's 4-dot test, was significantly higher in patients with high AC/A than in those with TPF (35.3% vs. 4.3%, p = 0.029). The mean preoperative angles of deviation in TPF and high AC/A types were $28.3{\pm}4.4$ and $28.8{\pm}4.5PD$ at distances, and $14.7{\pm}4.2$ and $15.1{\pm}4.1PD$ at near. Twelve months after surgery, the mean angles of deviation in TPF and high AC/A types were $2.9{\pm}9.8$ and $1.2{\pm}9.6PD$, respectively, at distance and $1.7{\pm}7.7$ and $-1.3{\pm}11.3PD$ at near. The surgical success rates were similar in the TPF and high AC/A types (74.0% vs. 64.7%). Five (21.7%) patients with TPF and 2 (11.8%) with high AC/A type experienced recurrence, with consecutive esotropia occurring in 1 (4.3%) patient with TPF and 4 (23.5%) patients with high AC/A. Conclusions: The proportion of diplopia at near was higher in patients with high AC/A type than in those with TPF intermittent exotropia. However, the surgical success rates were not significantly different between the types.

• 한국자원식물학회지
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• 제31권6호
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• pp.634-640
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• 2018

Aralia cordata (A. cordata), which belongs to Araliaceae, is a perennial herb widely distributed in East Asia. We evaluated the anti-inflammatory effect of stems (AC-S), roots (AC-R) and leaves (AC-L) extracted with 100% methanol of A. cordata and elucidated the potential signaling pathway in LPS-stimulated RAW264.7 cells. The AC-L showed a strong anti-inflammatory activity through inhibition of NO production. AC-L dose-dependently inhibited NO production by suppressing iNOS, COX-2 and $IL-{\beta}$ expression in LPS-stimulated RAW264.7 cells. AC-L inhibited the degradation and phosphorylation of $I{\kappa}B-{\alpha}$, which donated to the inhibition of p65 nuclear accumulation and $NF-{\kappa}B$ activation. Furthermore, AC-L suppressed the phosphorylation of ERK1/2 and p38. These results suggested that AC-L may utilize anti-inflammatory activity by blocking $NF-{\kappa}B$ and MAPK signaling pathway and indicated that the AC-L can be used as a natural anti-inflammatory drugs.

• Transactions on Electrical and Electronic Materials
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• 제7권5호
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• pp.235-239
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• 2006

Charge dynamics in polymeric materials after aged under ac electric field using the pulsed electroacoustic (PEA) technique is reported. The emphasis is placed on charge decay. The charge dynamics of the ac aged additive free low density polyethylene (LDPE) samples under dc bias differ from the sample without ac ageing, indicating changes brought in by ac ageing. It is believed that a slow decay rate of charge in the ac aged sample is related to the formation of deep traps in the material. However, chemical analysis by infrared spectroscope (FTIR) and Raman microscope reveals no significant chemical changes taken place in the bulk of the material after ac ageing. Further experiments on irradiated LDPE have revealed a similar behaviour, i.e. the charge decay is slower in irradiated samples than that of fresh sample. The findings presented clearly indicate that space charge measurement can be used as a diagnostic tool to monitor ageing in polymeric materials.

• 한국초전도ㆍ저온공학회논문지
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• 제8권4호
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• pp.1-7
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• 2006

This paper reviews AC loss characteristics of high $T_c$ superconductors. The mechanisms of AC loss generation are explained briefly, and AC losses are classified by the magnetic field components which generate them. A couple of analytical formulae of AC losses, which are useful for simple and rough AC loss estimations, are presented. AC loss characteristics of single BSCCO multifilamentary conductors and single YBCO coated conductors are reviewed based on previous experimental and numerical studies. AC loss characteristics of those two types of practical high $T_c$ superconductors are compared with each other.

• 해양환경안전학회지
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• 제16권2호
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• pp.235-240
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• 2010

백열전구를 대체하기위한 친환경 에너지 절약형 7w급 LED 램프의 구동을 위한 전원장치를 설계하였다. LED 램프는 칩 LED를 여러개 직 병렬로 연결하여 사용하게 되므로 적합한 직류 전압과 전류를 공급하여야 한다. 그런데 LED 램프는 상용 AC 220V 전원에 직접 연결해 사용하게 되므로 드라이버에는 전압제어와 전류제어가 포함된 AC/DC, DC/DC 전력변환기가 반드시 필요하게 된다. 따라서 본 논문에서는 램프의 LED 열에 따라 출력전압과 전류제어가 가능하며 변압기가 없는 간단한 구조의 LED 램프 드라이버를 설계하였다.

• 한국주조공학회지
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• 제25권2호
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• pp.88-94
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• 2005

The microstructure and mechanical property of the ceramic reinforced AC4C matrix composites processed by squeeze casting were investigated. In this study Kaowool and Saffil fiber which are ceramic reinforcements are used as preform materials. As a matrix material, Al-7wt.%Si-0.3wt.%Mg(AC4C) has been used. In case of Kaowool and Saffil/AC4C composites, 7.5 MPa squeezing pressure and minimum 7.0% binder amount are needed to produce sound composite materials. The tensile strength of Kaowool/ AC4C composite is lower than the matrix metal and this can be explained by the melt unfilling due to formed cluster of Kaowool reinforcements. But the mechanical properties of hardness, wear resistance and thermal expansion are better than the matrix materials due to the strengthening effect of ceramic reinforcements.

• Korean Journal of Acupuncture
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• 제22권1호
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• pp.75-84
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• 2005

Objectives : Acupuncture has been used as treatment of disease in the korean medicine. In this study, it was investigated that effects of reduction of acupuncture techniques of five evolutive phase for appling excess in the heart, kidney on cardiovascular system as blood pressure and renin and atrial natriuretic peptide (ANP) in plasma, cardiac hypertrophy. Materials and methods : The experiments were performed on Sprague Dawley rats, 2K1C hypertension model was prepared by constricting the left renal artery with a sliver clip. Animals were then divided into seven groups, 2K1C induced and no treated group (Control), acupuncture on SP3 HT7(AC-1), LR1 KI1 (AC-2), SP3 HT7 LR1 KI1 (AC-3). The treatments were performed once a day for 10 days in rats. Results : The results are that the blood pressure was significantly decreased at 15days in AC-1 group. The cardiac hypertrophy was significantly decrease in AC-3 group. The activity of plasma ANP was increased in all groups without AC-1 group and the that of plasma Rein was decrease in AC-1, AC-2 groups than control group. Conclusions : These results suggest that acupuncture at SP3 HT7 and SP3 HT7 LR1 KI1 can be used as a therapy for controlling renal hypertension induced by 2K1C in the rats.