2성분계 PZT 압전세라믹스의 Mole 比에 따른 전기적 특성에 관한 연구

설정식,이수대,강광용 경남대학교 환경문제연구소 1987 환경연구 Vol.9 No.-

Lead zirconate titanate (Pb (Zr_(x), Ti_(1-x)) O_(3)) piezoelectric ceramics were prepared from PbO, ZrO_(2) and TiO_(2). These oxides were wet ball-milled and were hot pressed at 1250℃ in 0_(2) for 4h at 50kg/cm^(2) finally, and were ascertained by x-ray diffraction experiments. Samples which were used for measurement, were classified into 5 types according to x-values and Curie temperatures determined for each samples, from the dielectric measurements at 1 KHz, are gradually lowered with the decrease of x-values and electromechanical coupling factors (k) which were calculated from the measurement of frequency-impedance relation are increased with the decrease of x-values. These results are fairly consistent with the ones reported previously.

고온가열 살균처리가 굴 통조림의 품질 특성에 미치는 영향

공청식,강수태,김종태,오광수 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-

보다 품질이 우수한 굴 통조림을 제조하기 위한 기초 자료를 제시할 목적으로, 원료 굴을 자숙한 후 301-3관에 충전, 밀봉하여 115℃에서 Fo값이 5~2O 되도록 가열살균처리를 하였으며 이같은 가열살균처리가 내용물의 물리적, 이화학적 성분의 변화 및 관능적 변화 등과 같은 굴 통조림의 전반적인 품질에 미치는 영향에 대하여 검토하였다. 제품의 수율은 Fo값이 증가할수록 약간씩 감소하였고, 수율은 79.2~83.7% 정도였다 가열처리중 시료 굴 통조림의 pH는 별 변화를 보이지 않았고, 휘발성 염기질소는 원료 굴의 육 성분이 분해되어 휘발성 염기성분이 생성됨에 따라 열처리정도에 따라 상당량 증가하였다. 원료 굴의 주요 구성지방산은 14:0, 16:0, 18:In9, 20:5n3 및 22:6n3 으로서, 고온가열처리를 많이 받을수록 포화 및 모노엔산의 조성비는 약간씩 증가한 반면 플리엔산은 약간씩 감소하였다. 고도불포화지방산의 잔존율 역시 Fo값이 증가할수륵 상당히 감소하는 경향을 보였다. 시료 굴 통조림의 정미성분 중 유리아미노 산류는 자숙 및 가압 살균시 수분이 유출됨에 따라 처음에는 상당량 감소하였으나, 이후 열처리가 진행될수록 약간씩 증가하였다. Tau의 경우는 Fo값이 증가할수록 계속 감소하였다. Betaine은 생굴에 400.6 mg/100g으로 다량 함유되어 있었으며, 고온가열처리 중 상당량 감소하였다. 엑스분 중의 주요 무기이온성분은 Na, K, Mg 및 P 이었으며, 이들은 고온가열처리 중 Fo값이 증가할수록 상당량 감소하여 Fo 20 시료의 경우 대부분 무기이온성분들이 생굴에 비해 1/3 정도로 감소하였다. 조직감면에서는 고온에서의 열처리로 인한 조직의 연화보다는 가압에 따른 수분의 유출과 압착으로 인해 조직이 단단해지는 것으로 나타났다. 가열처리에 따른 굴 통조림의 관능적 특성의 변화에서 색조는 Fo값이 증가할수록 약간씩 갈변화되었고, 냄새는 가열처리를 많이 받을수록 대체로 좋은 평가를 받았다. 맛과 조직감은 가열처리의 정도에 따른 차이를 인지할 수 없었으며, 종합평가면에서 Fo 5~15시료간에는 유의적 차이가 인정되지 않았다. The boiled-oyster vacuum-packed in cylindrical can(No. 303-3) were thermally processed at 115℃ to reach Fo values of 5~20 min changes in food components and sensory evaluation of canned oyster by thermal processing at high temperature were investigated. The moisture contents of canned oyster meat decreased with the increasing of Fo values at 115℃, while crude protein contents relatively increased. The yield was slightly decreased with the increasing of Fo values(79.2 ~83.7% degrees), and volatile basic nitrogen(VBN) contents increased markedly with the increasing of Fo value. In fatty acid composition of canned oyster, the composition ratio of saturates and monoenes such as 14:0, 16:0 and 18:In9 increased, while polyunsaturated fatty acids such as 20:5n3 and 22:6n3 decreased with the increasing of Fo value. In taste compounds, content of total free amino acid in raw oyster was 1,533.5 mg%, and this total content was slightly increase(1,140.8 mg%~l,266.2 mg% degrees) with the increasing of Fo values. The major free amino acids of canned oyster were Tau, Glu, Asp, Ala and Cys. But contents of betaine and ionic minerals such as Na, K, Mg and P decreased markedly by thermal processing at l15℃. As compared with Fo 5 min heat treatment; Fo 20 min heat treatment at 115'c became more hardened in texture of oyster meat. In sensory evaluations on organoleptic characteristics, no significant difference was observed among the canned oyster heated at Fo 5, 10 and 15 min.

珪酸마그네슘의 合成條件에 關한 硏究

전우정,신화우,최광식,안세민,이광표,장영수 원광대학교 식품약품안전성연구소 1993 食品藥品安全性硏究 Vol.6 No.-

Magesium twisilicate is mainly uaed as a nonsytemic antacid andabsrbent. Magnesium trisilicate when teeated with anacid sxuh as diluted hydrochloric acid in gastric juice decomposes to form Magnesium chloride and colloidal Silicates. 2MgO·3SiO_2 + 4Hcl - 2MgCl_2 + H_4Si_3O_8 (or 3SiO_2 + 2H_2O) Colloidal mixture The resultng colloidal silicates can protect ahe ulcer frdm further acid and peptic attack and possibly adsorb the pepsin. It is well known that yield of Magnesium trisilcate produced is greatly affected by the Synthesis condition such as the reactant concentration, reaction temperature and moleatio of reactant solutions as well as by the emperature at which the precipitate is dried and the temperature of washing water, etc. The purpose of this study is to investigate the optimum synthesis conditions of Magnesium trisilicate. A randomized complete block design suggested by G.E.P. Bdx and K.B. Wagnesium sulfate solution with Sodium silicate solution in this study. It was found that optimal synthesis conditidns were: Reaction temperature range : 57-90 ℃. Concentration range of reactants (Sodium silicate and Magnesium sulfate) : 19.1-29% molar ratio of the reactants. [Sodium silicate]/[Magnesium sulfate]: 1.47-1.80. temperature range of washing water: 45-48℃ and drying temperature range: 65-82℃ The antacidic activity of five Magnesium trisilicate samples which shows the maximum antacidic efficacy was tested by pharmacopeia acid consuming capacity test. The five Magnesium trisilicate samples were samples were identified by chemical analysis.

댐퍼붙이 거위목바이트를 使用하는 切削系의 動的 安定性에 關한 硏究

李炯植,鄭準基,盧光春 연세대학교 산업기술연구소 1982 논문집 Vol.14 No.2

The effect of the damped goose-neck tool upon the dynamic stability of machine tool was investigated. The dynamic stability of machine tool is directly related to the chatter in the metal cutting process. By the test of the dynamic characteristics for the damped goose-neck tool, theoretical approach of dynamic stability of machine tool is identified. It's results are compared with the results of actual cutting test. And the dynamic stability of machine tool is improved by the higher elasticity and the increase of damping coefficient for the damped goose-neck tool.

골아세포 MC₃T₃-E₁의 증식과 기능에 Insulin Like Growth Factor Ⅰ, Ⅱ 및 부갑상선 호르몬이 미치는 영향

윤현구,정호연,양인명,김성운,김진우,김광원,김영설,최영길,서광식 대한내과학회 1992 대한내과학회지 Vol.42 No.1

MC₃T₃-E₁골아세포군을 이용하여 IGF-Ⅰ과 Ⅱ를 투여하고 DNA합성과 골아세포기능을 측정하기 위해 PTH에 대한 C-AMP반응정도, alkaline phosphatase 활성도를 측정하여 다음과 같은 결과를 얻었다. 1) IGF-Ⅰ과 Ⅱ는 모두 DNA합성이 어느 농도까지는 증식효과를 나타내지만 그 이후에는 억제되는 양상을 보였다. 2) PTH에 대한 골아세포의 C-AMP반응으로 증가되었지만 IGF-Ⅰ과 Ⅱ의 투여시 농도변화에 따른 의미있는 변화는 없었다. 3) 본 실험의 조건에서 alkaline phosphatase 활성도는 증가되지 않았다. 이상의 결과로 MC₃T₃-E₁ 골아세포에 IGF-Ⅰ과 Ⅱ는 세포의 증식을 자극하여 PTH는 C-AMP생성을 촉진하는 효과가 있었다. The effect of insulin-like growth factor (IGF) Ⅰ and Ⅱ on cloned MC₃T₃-E₁ cells that had osteoblastic activity was examined by [³H] thymidine incorporation into DNA, cyclic AMP responsiveness to parathyroid hormone (PTH), and alkaline phosphatase activity. IGF Ⅰ and Ⅱ stimulated the growth and proliferation of osteoblastic cells at 20ng/㎖ and 50ng/㎖, respectively. We next examined the effect of IGF-Ⅰ and Ⅱ on the expression of osteoblastic activity. Adenylate cyclase response of PTH to IGF-Ⅰ and Ⅱ-treated cells showed maximal stimulation at 10 and 50㎚PTH, respectively, but IGF Ⅰ and Ⅱ induced limited activity of osteoblastic function. In conclusion, IGF-Ⅰ and Ⅱ were potent stimulators to the growth of osteoblastic cells but did not have an immediate effect on expression of osteoblastic function in this experiment.

Humic acid가 카드뮴 어독성에 미치는 영향

류지성,정규혁,최필선,이길철,최덕일,최성수,류홍일,박광식 한국환경독성학회 1998 환경독성보건학회지 Vol.13 No.1

Cadmium, a major aquatic pollutant in many parts of the world, is toxic and readily accumulated in aquatic organisms. It mainly exists in water as complexes with organic ligands such as dissolved organic carbon and this complexation is known to have effects on the aquatic toxicities. In this study, acute toxicity, histology, and bioaccumulation were studied to evaluate effects of humic acid on cadmium toxicity and bioavailability to fish using Oryzias latipcs and Cypriruts carpio. 96h~LC50 of cadmium was 6.38 mg/L using Oryzias latipes. However, the mortality showed the dose-dependent decrease when humic acid was added to the test solution. When fish were exposed to 5 mg/L of cadmium, histological changes in the exposed organs (caudal fins, gills, kidney, liver, and gut) of Cyprinifs carpio were decreased by humic acid, especially in kidney and liver. Bioaccumulation of cadmium also decreased by treatment of humic acid. It seems that the formation of complexes between cadmium and humic acid may decrease bioavailability of cadmium to fish, and thus reduce the toxic effects of cadmium.

Humic acid가 카드뮴 어독성에 미치는 영향

류지성,정규혁,최필선,이길철,최덕일,최성수,류홍일,박광식 성균관대학교 약학연구소 1998 成均藥硏論文集 Vol.10 No.1

Cadmium, a major aquatic pollutant in many parts of the world, is toxic and readily accumulated in aquatic organisms. It mainly exists in water as complexes with organic ligands such as dissolved organic carbon and this complexation is known to have effects on the aquatic toxicities. In this study, acute toxicity, histology, and bioaccumulation were studied to evaluate effects of humic acid on cadmium toxicity and bioavailability to fish using Oryzias latipes and Cyprinus carpio. 96h-LC50 of cadmium was 6.38 ㎎/L using Oryzias latipes. However, the mortality showed the dose-dependent decrease when humic acid was added to the test solution. When fish were exposed to 5㎎/L of cadmium, histological changes in the exposed organs(caudal fins, gills, kidney, liver, and gut) of Cyprinus carpio were decreased by humic acid, especially in kidney and liver. Bioaccumulation of cadmium also decreased by treatment of humic acid. It seems that the formation of complexes between cadmium and humic acid may decrease bioavailability of cadmium to fish, and thus reduce the toxic effects of cadmium.

전처리방법에 따른 새송이 된장절임의 품질특성 변화

황성희,정헌식,윤광섭 동아시아식생활학회 2004 동아시아식생활학회지 Vol.14 No.3

This study was conducted to find the optimum pretreatment method to improve the quality of Pleurotus eryngii pickled with the fermented soybean paste. Blanching(70 , 10min), salting(5%, 20 , 72hr) and drying(50 , 3hr) were used as pretreatment methods. The moisture loss of the mushrooms during pickling was accelerated more by salting and drying. Salinity increase was retarded by salting. Surface and internal browning of the mushrooms were suppressed by blanching. Hardness tended to increase sharply until 20 days of pickling and then slowly decreased. In the sensory evaluation, mushrooms pickled for 40 days were scored as the highest. Blanching was a superior treatment compared to the others in term of color, taste, flavor, texture and overall acceptability.

감초추출물 첨가가 청국장의 품질에 미치는 영향

황성희,정헌식,김순동,윤광섭 동아시아식생활학회 2004 동아시아식생활학회지 Vol.14 No.6

This study was conducted to investigate the effects of Glycyrrluizia uralensis water extract on the quality of Cheonggukjang(fermented soybean paste). Soybeans were soaked for 24 hrs, steamed for 1 hr at 121 , mixed with G. uralensis extract(0, 1, 3 and 5%) and fermented for 54 hrs at 40 after inoculation of Bacillus lichenifomis. The amounts of viscous substance and reducing sugar, and pH of the products were increased when the G. uralensis extract was added. The color of the products was changed to dark yellow by the addition of G. uralensis extract. Ammonia odor and bitter taste decreased as the G. uralensis extract content increased. The products added with 5% of G. uralensis extract showed higher acceptability scores than the others. Results suggest that the water extract of G. uralensis could be used as an additive to improve the quality of Cheonggukjang.

全南地方의 韓牛에 發生하고 있는 原因不明의 急性疾患에 關한 硏究(豫報)

康炳奎,金廣植,李政吉 全南大學校 農漁村開發硏究所 1973 農業科學技術硏究 Vol.7 No.-

Studies were made on the etiology of the acute, unknown disease of Korea cattle in Chonnam area. Total 12 cattle reared in the infected area were selected and examined periodically from May to November in 1972. Of the 12 cattle, two were died during the experiment. They were autopsied and histopathologically examined. In order to compare with symptoms and histopathological changes of died cattle, three goats were poisoned with phenylmercuric-triethanol-ammonium borate(PTAB), sodium nitrate(NaNO₃), and potassium cyanide(KCN). Meanwhile, samples of water, soil, and feedstuffs from the infected and noninfected area were analysed. Results obtained and matters presumed were as follows: 1. Chemical examinations for blood revealed that Korean cattle reared in the infected area had pronounced hypomagnesemia and hypocalcemia. The total leukocyte count was gradually increased in the blood examination of the two Korean cattle died during the experiment. In the analysis of soil, water, and feedstuffs of the infected and noninfected area, the differences were noted in the values of magnesium, calcium, and nitrate nitrogen. 2. Similar histopathological changes of liver and kidney in died cattle and poisoned goats led us to suspect a toxic substance. 3. Next studies should include the blood examination for calcium, magnesium, nitrate and nitrite nitrogen, cyanide, copper, vitamine A, and methemoglobin. Further investigations on soil, water, and feedstuffs are also desired.