Microstructure‑Strengthening Interrelationship of an Ultrasonically Treated Hypereutectic Al–Si (A390) Alloy

Soo‑Bae Kim,Young‑Hee Cho,Jae‑Gil Jung,Woon‑Ha Yoon,Young‑Kook Lee,Jung‑Moo Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

Ultrasonic melt treatment (UST) was applied to an A390 hypereutectic Al–Si alloy in a temperature range of 750–800 °Cand its influence on the solidification structure and the consequent increase in strength was investigated. UST at such a hightemperature, which is about 100 °C above the liquidus temperature, had little effect on the grain refinement but enhanced thehomogeneity of the microstructure with the uniform distribution of constituent phases (e.g. primary Si, α-Al and intermetallics)significantly refined. With the microstructural homogeneity, quantitative analysis confirmed that UST was found tosuppress the formation of Cu-bearing phases, i.e., Q-Al5Cu2Mg8Si6, Al2Cuphases that form in the final stage of solidificationwhile notably increasing the average Cu contents in the matrix from 1.29 to 2.06 wt%. A tensile test exhibits an increasein the yield strength of the as-cast alloy from 185 to 208 MPa, which is mainly associated with the solute increment withinthe matrix. The important role of UST in the microstructure evolution during solidification is discussed and the mechanismcovering the microstructure-strengthening interrelationship of the ultrasonically treated A390 alloy is proposed.

Propofol과 Enflurane 마취중 발생한 심부정맥

이수일,여광환,황기백,이황재,이종국 大韓臨床藥理學會 1998 臨床藥理學會誌 Vol.6 No.2

低溫貯藏魚類 中의 低溫性 大腸菌群에 關한 硏究

鞠重烈,張壽賢,金鍾培 군산대학교 1979 群山水産專門大學 硏究報告 Vol.13 No.3

In this study, the total bacterial count and coliforms MPN in samples stored at 5℃ investigated. The distribution, biochemical character and growth temperature of Psychrotrophic coliforms isolated from samples during cold storage were studied, also. The results were as follows : 1.The increasing rate of Psychrotrophic bacterial flora in samples was higher than that of Psy-chrotrophic coliforms. 2.In 213 strains of coliforms isolated from samples, 181 strains were Psychrotrophic coliforms. 3.The isolated Klebsiella aerogenes and Citrobacter freundii from samples were superior in number, showing 106 strains for Klebsiella aerogenes while 54strains for Citrobacter freundii. 4.The number of Klebsiella aerogenes and Citrobacter freundii of isolating Psychrotrophic coliforms showed maxima compared with others of Psychrotrophic coliforms.

Micral-Test^TM을 이용한 미세단백뇨 측정의 임상적 유용성

문대수,이국일 조선대학교 1994 The Medical Journal of Chosun University Vol.19 No.1

The excretion of small quantities of urinary albumin (microalbuminuria) might the earliest clinical sign of incipient diabetic nephropathy and important predictor of renal failure in diabetes. Currently methods available to detect microalbuminuria were not suitable for routine screening. A test strip (Micral-Test_TM : Boehringer Mannheim GmbH, Germany) based on dry immnunochemical principles had recently been developed which allows semiquantitative detection of urinary low albumin concentration. We measured microalbuminuria by Micral-Test_TM and compared with any other items. The results were summerized as follows : 1. The relationships of the duration of diabetes to microalbuminuria was low positive association (r=0.332l). 2. Results obtained by Micral-Test_TM correlated closely with values obtained by rate nephelometry (r=0.7998). 3. There were statistically significant difference in BUN between positive and negative results of Micral-Test_TM(p<0.05), but no significant difference in FBS TG, total cholesterol, creatinine and BP . 4. There were statistically significant difference in BUN, creatinine BP between positive and negative results of N-Multistix SG_TM(p<0.001, p<0.01, p<0.05), but no significant difference in FBS, TG, total cholesterol. 5. The detection discrepancy rate of albuminuria in diabetes between Micral-Test_TM and N-Multis- tix SG_TM was 12.9%. In conclusioin, Micral-Test_TM was a good screening method for easy and quick detection of microalbuminuria and monitoring the development of urinary albumin excretion in the microalbuminuric range.

유용미생물 고정용 세라믹 담체의 제조 및 부착능

김수룡,김용국,이종국,황인옥 조선대학교 생산기술연구소 2006 生産技術硏究 Vol.28 No.2

Effective micro-organisms (EM) increase the natural resistance of soil and plants, and it considerably improves the quality and fertility of soil as well as the growth and quality of crops. In this study, Porous ceramics were prepared with various ceramic types and were observed that EM was attached on the pores inside. EM was well attached on various porous ceramics. However, attachment ability of EM on surface was better than that of EM inside. Open pore is essential to attach EM inside of ceramics. From this result, potential application for environment purification ceramics was confirmed and made it to use in a field of environmentally-friendly.

김장용배추 품종별 절임배추의 저장성 검토

강국희,이인선,박완수 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.2

The ferrnetnation characteristics and microbial changes during the storage of salted Chinese cabbage cultivars were investigated. When 10 Chinese cabbage cultivars produced in fall were salted up to 3 and stored at 0%, their pHs were lowered with different modes. and total acid contents were increased with the same way as pH. Results on microbial counts was the best in "noranmat'.

官能檢査法에 의한 아이스크림의 品質評價에 관한 硏究 : (弟1報)市販 아이스크림의 成分分析 및 官能的 品質評價 試驗

채수규,이상건,심상국 서울保健大學 1982 論文集 Vol.2 No.1

시판 Carton 및 Cone형 아이스크림에 대한 化學成分 分析 및 脂肪成分의 理化學的 性質을 조사하고, 또한 選拔 및 訓練된 파넬에 의해 官能的 品質 評價試驗을 실시하여 다음과 같은 결과를 얻었다. 1) 시판 아이스크림 중의 脂肪, 總固形分, 總蛋白質, 無脂乳固形分, 乳糖 및 粗灰分 함량은 製造會社 別로 큰 차이가 없었으며, 그들의 평균 함량은 각각 Carton형이 8.53%, 34.18%, 3.43%, 11.02%, 6.17% 및 0.84%이었고 Cone형이 6.54%, 34.02%, 3.29%, 10.40%, 5.84% 및 0.77% 이었다. 2) 抽出된 아이스크림 脂肪의 酸價, 감화가 , 요요드價 및 Reichert-Meissl價는 製造會社 別로 다소간의 큰 차이를 나타내었으며, 그들의 평균값은 각각 Carton형이 0.58, 221.88, 19.63 및 29.04 이었고, Cone형이 0.65, 219.45, 18. 64 및 28.82 이었다. 3) 시판 4개회사 제품의 아이스크림을 시료로 하여 3點試驗法, 順位試驗法 및 採點試驗法에 의한 官能的 品質 評價試驗을 실시한 결과 거의 5% 수준 이상에서 製造會社別로 有意的인 차이가 인정되었으며, Carton 및 Cone형 모두가 C 및 D 會社 製品의 아이스크림이 A 및 B 會社 製品의 것보다 우수하게 평가되었다. Commercial ice creams were subjected to chemical analysis and sensory evaluation by trained panel members. Chemical composition of commercial ice creams was not much different among the makers. The average contents of fat, total solid, total protein, milk solids-not-fat, milk lactose and crude ash were 8.53%, 34.18%, 3.43%, 11.02%, 6.17% and 0.84% in Carton, and 6.54%, 34.02%, 3.29%, 10.40%, 5.84% and 0.77% in Cone, respectively. Chemical properties of fat extracted from commercial ice creams were much different among the makers. The average values of acid, saponification, iodine and Reichert-Meissl value were 0.58, 221.88, 19.63 and 29.04 in carton, and 0.65, 219.45, 18.64 and 28.82 in cone. According to the results of triangle, ranking and scoring tests for commercial ice creams produced by four makers, significant difference on the sensory quality among four commercial ice cream samples was recognized at over 5 percent level. C and D samples had better sensory quality than A and B in both type of Carton and Cone.

^(99m)TC Phytate 간스캔에 있어서 정량적 간외섭취율의 임상적 의의

김병수,문태용,김건일,남상화,한국상 부산의대 1991 부산의대잡지 - 부산대학교 의과대학 Vol.31 No.2

등줄쥐의 生態와 防除

姜壽遠,申源國 세계평화교수협의회 1973 아카데미論叢 Vol.1 No.1

들쥐의 피해를 방제하기 위하여 기초적인 생태연구를 수원시내에 위치한 서울대 농대 농장에서 1972년 봄부터 가을까지 그리고 방제연구를 광주지역에서 수행한 결과를 요약한다. (1) 3월 31일부터 7월까지 채집된 105마리의 들쥐류를 분류한 바 그중 97마리(92%)가 등줄쥐 Apodemus agrarius coreae이고 나머지는 비단털쥐 1.5%와 시궁쥐 1.5%이었다. (2) 농대농장에 있어서 등줄쥐의 서식밀도는 50/㏊로 같은 지역에서의 1970년도의 55/㏊에 비하면 적었고 성비는 거의 ♂ : ♀ ≒ 2 : 1이다. (3) 등줄쥐의 한개의 쥐집에는 쥐구멍(출입구)이 2개 이상이고 봄(4월)에 조사한 결과 저장 식량은 전무했고 쥐집중 70%가량은 쥐가 발견되지 아니했다. (4) 사육중인 등줄쥐의 수명은 수컷이 평균 544일이고 암컷이 평균 347일이었다. (5) 새로운 살서제(쥐약)인 신석반하제는 등줄쥐에 대한 기피성이 전무하고 기호성은 높으나 치사시간이 6~72시간이 소요되는 완효성 쥐약이다. 그리고 한번 투약이 6~8개월간 약효가 계속되며 LD_50=0.0287g/㎏ LD_100=0.600g/㎏이다. (6) Bait box(쥐약 투여상자) 속에 놓은 살서제를 등줄쥐가 취식하는 효과에 있어서는 conselt(1)과 (2)가 가장 좋고 다음의 상자형, 원통형이며 그리고 원주형과 삼각형 baitbox가 가장 나빴다.

활석을 이용한 사포나이트의 수열합성

배인국,장영남,채수천,류경원,최상훈 한국광물학회 2003 광물과 암석 (J.Miner.Soc.Korea) Vol.16 No.2

삼팔면체형의 스멕타이트계 사포나이트(saponite)를 천연 광물질인 활석을 이용하여 수열법에 의해 합성하였다. 출발물질은 활석에 Na₂CO₃를 첨가하여 공기중에서 800℃로 가열한 후, 화학양론적 조성에 맞게 Al(No₃)₃·9H₂O 및 Mg(No₃)₂·6H₂O 금속염 수용액을 첨가하였고, pH는 7∼12 범위 내로 NH₄OH 수용액에 의해 조절하여 제조하였다. 수열반응 조건은 약 1리터의 수열반응 용기에서 230 ℃, 압력은 25∼75 kgf/㎠의 범위 내에서 10∼60시간이었다. 실험결과, 반응온도 및 회전속도를 230℃와 180 rpm으로 고정시킨 수열조건 하에서 반응시간, 반응압력, pH 조건을 각각 40시간, 25 kgf/㎠, 약 10으로 하였을 때, 그리고, 화학조성을 화학양론적 조성에 필요한 Na₂O의 양보다 200% 과량 추가하였을 때, 양호한 사포나이트가 합성되었다. 또한 압력을 75 kgf/㎠까지 증가시켜도 결정도에 미치는 영향은 미미하였으며, 반응시간이 길수록 더 좋은 결정도를 나타냈다. Saponite was synthesized from talc by hydrothermal method. The starting material was prepared by adding Al(N0₃)₃·9H₂0 and Mg(N₃)₂·6H₂O solution to the talc powder, which was previously activated in air at 800℃ together with Na₂C0₃. The alkalinity of the solution was controlled by NH₄0H solution. The autoclaving was carried out in the closed stainless steel vessel (about 1 liter) for 40 hours under the pressure of 25 ㎏f/㎠ at 230℃. The characterization of the reaction product shows that saponite was crystallized successfully. After the experimental results, pressure was not sensitive parameter in the range of 25-75 ㎏f/㎠, but longer reaction time results in better crystallinity.