• 한국강구조학회 논문집
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• 제16권1호통권68호
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• pp.11-20
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• 2004

본 눈문은 C.F.T구조에서 폐단면인 각형강관기둥과 H형강보의 접합방법중의 하나인 외측형 다이아프램을 대상으로 한다. 본 연구에서의 내력평가는 기존의 단순인장형 접합부 실험결과를 기초로 항복선이론을 이용한 내력평가, 범용 유한요소해석 프로그램을 이용한 비선형 해석, 규준식 등을 통하여 수행되었다. 항복선이론은 수정된 K. Morita 역학모델을 이용하였고, 범용 유한요소해석프로그램은 Abaqus/Standard를 사용하였으며 비탄성 정역학적 유한요소해석을 하였다. 규준식에서의 최대내력 예측식은 장기하중에 대한 계수와 재질을 고려한 항복비를 적용하였으며, 규준식에서의 항복내력은 비충전형의 경우 2.6의 안전율을 갖는 값으로 하였고, 충전형의 경우 2.2의 안전율을 갖는 값으로 하였다. 연구결과, 본 연구에 사용된 기존의 단순인장형 접합부 내력평가는 항복선이론, 유한요소해석, 규준식을 통하여 모두 가능한 것으로 판단되며, 이들 중 규준식이 기존의 실험결과를 가장 과소평가하였다. 유한요소 해석결과에서의 내력과 변형모듈은 기존의 단순인장형 접합부 실험결과와 잘 일치하였다.

• 수산해양기술연구
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• 제14권2호
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• pp.63-68
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• 1978

일본에서 멸치를 어획하는데 보편적으로 쓰이고 있는 파치망의 성능을 알기 위하여 1/20 크기의 모형어구를 제작하여 해상에서 예인하여 실험한 결과는 대략 다음과 같다.1. 어구의 전저항 $R_p$(kg)과 끝자루만의 저항 $R_b$(kg)은 예망속도 v(m/sec)가 $0.3\leqv\leq0.7$의 범위에 있을 때는 $R_p=69.6 V_{I.66}$ $R_h=37 v^2$라고 표현된다. 2. 그물꼴로서는 끝자루가 구김살없이 전개되고 수비부분이 재래식과 같이 봉소마모양이 되지 않으며, 날개끝에 여분의 망지가 없는 점을 장점이라고 볼수 있다. 그러나 그물목줄 길이는 날개끝의 도개깊이, 뜸줄쪽 그물목줄 및 발줄쪽 그물목줄의 길이 사이에 피타고라스정리가 성립되도록 조정할 필요가 있고, 또 날개 끝에 지나치게 무거운 추를 채우는 것도 바람직하지 않은 것 같다. 또 자루(문턱과 천장망사이)의 전개 깊이의 끝자루의 그것에 대한 비는 2:1정도이며, 어구 크기에 비하여 그 비가 그다지 크지 않은 것 같다. 또 예인속도가 빨라지면 문턱 밭줄이 날개끝 보다 들어 올려지는데, 이것을 시정하기 위해서는 끝자루 장력의 전달방식을 개선할 필요가 있다고 보아진다.은 韓國에 도입 된지 반세기가 넘었다. 그 동안 漁法이 引寄網에서 引廻網으로 발달하였고 漁具材料중 일부가 함성섬유로 대치되 있으며, 揚網機에 의한 날개그물의 양망등 상당한 발달을 하였다. 그러나, 漁具의 기본 형태는 引寄網시대의 원형에서 크게 벗어나지 않은 채 그저 확대되어 온 것에 지나지 않으며, 그물그물은 여전히 人力으로서 揚網되고 있어서 省力化를 위한 漁具, 漁船, 漁撈裝備의 개량이 요망되고 있다. 權現網漁業에 관한 硏究로서는 在來式漁具의 그물꼴에 관하여 李 梁 徐 孫(1971)이 1/10 크기의 模型漁具로써 연구한 것 이외는 없다. 다만 1972년 부터는 기선권 현망 수산업협동조합에서 일본식 파치망을 도입하여 실지 조업 시험을 실시한 바 있으며, 재래식의 반정도의 인력으로서 조업이 가능하므로 보편화되는가 했더니 어획성능이 좋지않아서 계속되지 않았다. 그러나 이 漁具는 일본에서는 보편적으로 쓰이고 있는것이므로 다른형의 漁具의 개발에 앞서이 漁具의 장단점을 규명하여 새로은 漁具의 개발이 참고가 되게 하고자 그 것의 모형실험을 실시하였다.의 개발이 참고가 되게 하고자 그 것의 모형실험을 실시하였다.

• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2004년도 총회및 심포지움
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• pp.67-72
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• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml $h^{-1}\;m^{-2}\;atm^{-1}$ at $5^{\circ}C\;and\;99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%\;CO_2+1\;or\;20\%\;O_2,\;8\%\;CO_2+1\;or\;20\%\;O_2,\;or\;12\%\;CO_2+20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2+1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SSC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown using black polyethylene mulch under NF was over 7-fold that of slices from tomato fruit grown using hairy vetch under Tom-Cast. When stored at $20^{\circ}C$, slices from light-red tomato fruit grown with black polyethylene or hairy vetch mulches both showed a rapid increase in electrolyte leakage beginning 6 hours after slicing. However, slices from tomato fruit grown using the hairy vetch mulch tended to have lower electrolyte leakage than those grown with black polyethylene mulch. These results suggest that tomato fruit from plants grown using hairy vetch mulch may be more suitable for fresh-cut slices than those grown using black polyethylene mulch. Also, use of the disease forecasting model Tom-Cast, which can result in lower fungicide application than is currently used commercially, resulted in high quality fruit for fresh-cut processing. Experiments were conducted to determine if ethylene influences chilling injury, as measured by percentage of slices exhibiting water-soaked areas in fresh-cut tomato slices of 'Mountain Pride' and 'Sunbeam' tomato (Lycopersicon esculentum Mill.). Ethylene concentration in containers without ventilation significantly increased during storage at $5^{\circ}C$, whereas little or no accumulation of ethylene occurred in containers with one or six perforations. Chilling injury was greatest for slices in containers with six perforations, compared to slices in containers with one perforation, and was over 13-fold greater than that of slices in control containers with no perforations. An experiment was also performed to investigate the effectiveness of including an ethylene absorbent pad in containers on subsequent ethylene accumulation and chilling injury. While ethylene in the no-pad controls increased continually during storage of both 'Mountain Pride' and 'Sunbeam' tomatoes at $5^{\circ}C$ under modified atmosphere conditions, no increase in accumulation of ethylene was observed in containers containing ethylene absorbent pads throughout storage. The ethylene absorbent pad treatment resulted in a significantly higher percentage of chilling injury compared with the no-pad control. In studies aimed at inhibiting ethylene production using AVG during storage of slices, the concentration of ethylene in control containers (no AVG) remained at elevated levels throughout storage, compared to containers with slices treated with AVG. Chilling injury in slices treated with AVG was 5-fold greater than that of controls. Further, we tested the effect of ethylene pretreatment of slices on subsequent slice shelf-life and quality. In slices treated with ethylene (0, 0.1, 1, or $10\;{mu}L\;L^{-1}$) immediately after slicing, ethylene production in non-treated controls was greater than that of all other ethylene pre-treatments. However, pretreatment of slices 3 days after slicing resulted in a different pattern of ethylene production during storage. Ihe rate of ethylene production by slices treated with 1 L $L^{-1}$ ethylene 3 days after slicing was greater during storage than any of the other ethylene treatments. With slices pre-treated with ethylene, both immediately and 3 days after slicing, the rate of ethylene production tended to show an negative correlation with chilling injury. Chemical name used: 1-aminoethoxyvinylglycine (AVG).

• Clinical and Experimental Reproductive Medicine
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• 제11권2호
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• pp.51-57
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• 1984

The success of human in vitro fertilization (IVF) & embryo transfer (ET) has focused attention on the culture conditions that can provide optimal development of the preimplantation embryo. Studies of in vitro fertilization using mouse have direct implications to human IVF, since similar conditions are used for both species. Mouse IVF as a quality control system for human IVF & ET was studied since Feb., 1984. The results were as follows: 1. Egg retrieval following superovulation in IeR mice was l5.1${\pm}$5.3 eggs ovulated/mouse (Mean${\pm}$ S.D.) 2. In vitro cleavage rate was 61.7% (1146 eggs cleaved/l858 eggs inseminated) and % blastocyst was 42.6%. 3. In comparison with two media of Ham's F-10 and m-KRB, in vitro cleavage rate were 40.9%/63.l% and %blastocyst were 44.3%/61.2% (P<0.05). 4. It was concluded that mouse IVF system has a valuable place in human IVF & ET as a quality-control system and in human reproductive physiology as a research model.

• 천문학회보
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• 제36권2호
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• pp.103.1-103.1
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• 2011

Recent observations by Hinode show weakly-attenuated coronal loop oscillations in the presence of background flow (Ofman & Wang 2008, A&A, 482, L9). We study the vertical kink oscillations in solar coronal loops, considering field aligned flows inside the loops as well as surrounding the loops environment. The two dimensional numerical model of straight slab is used to explore the excitation and attenuation of the impulsively triggered fast magnetosonic standing kink waves. A full set of time dependent ideal magnetohydrodynamics equations is solved numerically taking into account the value of flow of the order of observed flows detected by SOT/Hinode. We find that relaxing the assumption of the limited flows within the loops enhances the damping rate of the fundamental mode of the standing kink waves by 2 - 3 % as compared to flow pattern which is basically localized within the loops. We further notice that extending the flow pattern beyond the loop thickness also enhances the strength of the shock associated with slow magnetoacoustic waves, recognized as an addition feature detected in the numerical simulation. The wider out-flow pattern destroys the oscillation patterns early as compared to narrower flow pattern, in other words we can say that it affects the durability of the oscillation. However, for the typical coronal loops parameters we find that the observed durability periods of the SOT/Hinode observation can be achieved with an out-flow Gaussian patterns for which half-width is not greater than factor 2.0 of the loop-half-width. explain a possible relation between electric current structure and sigmoid observed in a preflare phase.

• 한국식품과학회지
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• 제40권6호
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• pp.707-711
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• 2008

본 연구의 목적은 발효차 중에 미량물질로 존재하는 purpurogallin 유도체의 항염증에 대한 효과를 검토하고자 실시하였다. 특히 발효차에 존재하는 미량 성분들에 대한 생리활성 연구보고는 많지 않은데 이러한 이유는 미량성분을 기술적으로 발효차로부터 분리 정제하기가 매우 어렵기 때문으로 판단된다. 특히 녹차잎에 존재하는 페놀 화합물중 하나인 gallic acid는 발효과정 중 benzotropolone 구조를 가지는 purpurogallin 유도체를 새롭게 만드는 것으로 알려져 있는데 본 연구에서는 gallic acid 화합물이 이러한 과정 중에 생성하는 산화물을 효소적 산화 모델시스템인 peroxidase/hydrogen peroxide 모델을 이용하여 산화물을 얻은 후 컬럼크로마토그라피법을 이용하여 순수 분리하였다. 이 과정에서 purpurogallin carboxylic acid(PCA)를 gallic acid의 산화물로 분리할 수 있었고 이의 구조를 $^{1}H$ NMR, $^{13}C$ NMR 및 MS 분석방법을 이용하여 확인할 수 있었다. 이후 단리되어진 PCA의 항염증 효과를 검토하였다. RAW264.7 세포를 이용하여 PCA의 항염증 효과를 검토하였는데 PCA 100, 75, $50{\mu}g/mL$ 처리는 NO의 생성을 LPS만 처리한 세포에 비해 각각 57.6, 41.5, 21.8%를 유의적으로 저해시키는 것으로 나타났다. PCA 100, $75{\mu}g/mL$ 처리군에서 LPS만 처리한 RAW264.7 세포에 비해 IL-6의 생성이 각각 43.1, 23.9% 억제되어지는 것으로 관찰되었다. 또한 유사한 경향으로 PCA 100 및 $75{\mu}g/mL$ 처리군에서 LPS만 처리한 RAW264.7 세포에 비해 $PGE_2$의 생성이 각각 29.0% 및 15.4% 억제 되어지는 것으로 관찰되었다. 최근 생리활성을 가지는 신물질의 탐색 및 신소재 개발의 중요성이 부각되고 있다. 특히 선진국의 신물질의 개발에 의한 물질 특허가 증가하고 있고, 이에 따라 국내에서도 국제 경쟁력을 확보하기 위한 새로운 소재 개발이 시급한 상황이다. 본 연구 결과는 gallic acid의 산화물인 purpurogallin 유도체를 이용한 항염증 소재의 적용 가능성을 검토한 주요한 결과로 사료되어진다. 또한 본 연구를 통하여 발효차에 미량으로 존재하는 화합물들의 생리활성을 확인할 수 있었으며, 발효차에 포함되어 있는 미량 성분들의 항염증 관련 신소재 개발 가능성을 검토할 수 있었다.

• Journal of Korean Society for Atmospheric Environment
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• 제16권E호
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• pp.19-27
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• 2000

Particle Induced X-ray Emission (PIXE) and Elemental Analysis Syztem (EAS) were applied to the investiga-tion of the Characteristics and sources of wintertime atmospheric aerosols in Seoul. Atmospheric aerosols were collected by both fine and coarse fractions using a two-stage filter pack sampler from Kon-Kuk university during the winter season of 1999. PIXE was applied to the analysis of the middle and heavy elements with atomic numbers greater than 14(Si) and EAS was applied to the measurement of the light elements such as H, C and N. The fact that 64.2% of mass of fine particles in Seoul consists of the light elements (N, C , and H) suggests that the measurement of light elements is extremely important. The average mass concentration is Seoul was 38.6$\mu\textrm{g}$m(sup)-3. Elements such as Ca, Fe, Mg, and Ti appeared to have very low Fine/Coarse ratios(0.1∼0.4), whereas che-mical components related to anthropogenic sources such as Br, V, Pb, and Zn were observed to accumulate in the fine fraction. In the Asian Dust Storm(ADS) event, the concentation of soil components increased dramatically. Reconstruction of the fine mass concentrations estimated by a newly revised simple model was fairly in good agreement with the measured ones. Source identification was attempted using the enrichment factor and Pearsons coefficient of correlation. The typical elements derived from each source could be classified by this method.

• Parasites, Hosts and Diseases
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• 제45권4호
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• pp.255-266
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• 2007

The protective effect of the Synadenium carinatum latex lectin (ScLL), and the possibility of using it as an adjuvant in murine model of vaccination against American cutaneous leishmaniasis, were evaluated. BALB/c mice were immunized with the lectin ScLL (10, 50, 100$[\mu}g$/animal) separately or in association with the soluble Leishmania amazonensis antigen (SLA). After a challenge infection with $10^6$ promastigotes, the injury progression was monitored weekly by measuring the footpad swelling for 10 weeks. ScLL appeared to be capable of conferring partial protection to the animals, being most evident when ScLL was used in concentrations of 50 and 100${\mu}g$/animal. Also the parasite load in the interior of macrophages showed significant reduction (61.7%) when compared to the control group. With regard to the cellular response, ScLL 50 and 100 ${\mu}g$/animal stimulated the delayed-type hypersensitivity (DTH) reaction significantly (P < 0.05) higher than SLA or SLA plus ScLL 10 weeks after the challenge infection. The detection of high levels of IgG2a and the expression of mRNA cytokines, such as IFN-$\gamma$, IL-12, and TNF-$\alpha$ (Th1 profiles), corroborated the protective role of this lectin against cutaneous leishmaniasis. This is the first report of the ScLL effect on leishmaniasis and shows a promising role for ScLL to be explored in other experimental models for treatment of leishmaniasis.

• 한국식품과학회지
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• 제38권3호
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• pp.452-455
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• 2006

퇴행성뇌질환인 치매의 정확한 원인은 아직 불분명하나 빠른 뇌세포사멸이 주요한 원인으로 알려져 있다. 특히, 알츠하이머형 치매는 다량 생성되는 활성산소에 의한 뇌세포사멸이 주요원인인 것으로 입증되고 있다. 따라서 본 연구에서는 웅담활성성분인 UDCA의 세포보호 및 항산화효과로부터 알츠하이머형 치매와 같은 퇴행성 뇌질환억제 또는 치료물질로서의 가능성을 입증하고자 하였고 뇌의 대식세포인 소교세포(microglia)를 cell model로 하였다. MTT 실험결과 UDCA에 의한 세포보호효과는 $7.5\;{\mu}g/mL$ 주변 농도에서 관찰되었고 NO에 의한 세포손상 유도억제효과를 확인하였다(Fig. 2). 이와 같은 결과는 형광현미경하에서 보다 명확히 관찰되어(Fig. 3) 결국 UDCA에 의한 항세포사효과가 있음을 알 수 있었다. UDCA의 항산효과는 활성산소인 $H_2O_2$의 단백질 분해 저해능을 관찰하는 금속이온촉매 산화효과를 통해 확인하였다(Fig. 4). 즉, UDCA는 농도의존적으로$(1{\sim}100\;{\mu}g/mL)$ 단백질 분해억제능을 보였으며 $100\;{\mu}g/mL$ 이상의 농도에서 양성대조군인 ascorbic acid와 유사한 억제효과를 나타냈다. 이와 같은 UDCA의 항산화효과는 $10\;{\mu}g/mL$ 전후에서 관찰되어 세포보호효과를 나타내는 농도$(7.5\;{\mu}g/mL)$와 큰 차이가 없는 것으로 사료되었고 따라서 UDCA의 농도범주는 일괄적 적용이 가능할 것으로 판단된다. 결론적으로 웅담활성성분인 UDCA는 일반적으로 사용하여온 간질환 및 소화계질환의 보조요법제의 개념을 벗어나 항염 및 항산화효과에 잠재능을 가지며 나아가 뇌신경세포를 보호하고 세포사를 차단하여 알츠하이머와 같은 퇴행성뇌질환 조절 후보물질로 적용이 가능할 것으로 판단되나 보다 심도 있는 in vivo 및 임상적 차원의 연구가 요구된다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권7호
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• pp.1054-1060
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• 2017

Objective: This study was aimed at evaluating effects of cattle breed resources and alternative mixed-feeding practices on meat productivity and emission intensities from household farming systems (HFS) in Daklak Province, Vietnam. Methods: Records from Local $Yellow{\time}Red$ Sindhi (Bos indicus; Lai Sind) and 1/2 Limousin, 1/2 Drought Master, and 1/2 Red Angus cattle during the growth (0 to 21 months) and fattening (22 to 25 months) periods were used to better understand variations on meat productivity and enteric methane emissions. Parameters were determined by the ruminant model. Four scenarios were developed: (HFS1) grazing from birth to slaughter on native grasses for approximately 10 h plus 1.5 kg dry matter/d (0.8% live weight [LW]) of a mixture of guinea grass (19%), cassava (43%) powder, cotton (23%) seed, and rice (15%) straw; (HFS2) growth period fed with elephant grass (1% of LW) plus supplementation (1.5% of LW) of rice bran (36%), maize (33%), and cassava (31%) meals; and HFS3 and HFS4 computed elephant grass, but concentrate supplementation reaching 2% and 1% of LW, respectively. Results: Results show that compared to HFS1, emissions ($72.3{\pm}0.96kg\;CH_4/animal/life$; least squares $means{\pm}standard$ error of the mean) were 15%, 6%, and 23% lower (p<0.01) for the HFS2, HFS3, and HFS4, respectively. The predicted methane efficiencies ($CO_2eq$) per kg of LW at slaughter ($4.3{\pm}0.15$), carcass weight ($8.8{\pm}0.25kg$) and kg of edible protein ($44.1{\pm}1.29$) were also lower (p<0.05) in the HFS4. In particular, irrespective of the HSF, feed supply and ratio changes had a more positive impact on emission intensities when crossbred 1/2 Red Angus cattle were fed than in their crossbred counterparts. Conclusion: Modest improvements on feeding practices and integrated modelling frameworks may offer potential trade-offs to respond to climate change in Vietnam.