Effect of Ultrasonic Melt Treatment on Solidification Microstructure of Al–5Ti–1B Alloy Containing Numerous Inoculant Particles

Soo‑Bae Kim,Jae‑Gil Jung,Young‑Hee Cho,Su‑Hyeon Kim,Kwangjun Euh,Jung‑Moo Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The effect of ultrasonic melt treatment (UST) on the solidification microstructure of an Al–5Ti–1B alloy containing highvolumefractions of Al3Tiand TiB2particles is investigated for various UST times with different melt holding times. Theas-cast Al–5Ti–1B alloy is composed of TiB2and polygonal Al3Tiparticles (present prior to UST), plate-like Al3Tiparticles,and Al grains (formed during UST and/or solidification). The UST causes a size reduction and homogeneous distributionof the TiB2-agglomerated region containing many submicron-sized TiB2particles pushed to the grain boundaries. The USTslightly decreases the size and improves the distribution of polygonal Al3Tiparticles enriched in the TiB2-agglomeratedregion. Unlike the TiB2and polygonal Al3Tiparticles, which exhibit a minor refining effect, the plate-like Al3Tiparticlesshow a significant refinement with UST application. The UST has a significant effect on the size distribution of Al grains byinducing the formation of medium-sized grains at the expense of small and large grains; however, it only has a slight effecton grain refinement. The degree of microstructure modification increases with increasing UST time but decreases with meltholding time after UST. The mechanisms for the refinement and dispersion of the TiB2and Al3Tiparticles and Al grains arediscussed considering fragmentation, nucleation, and growth behaviors induced by the UST and subsequent solidification.

관동맥질환에서 저밀도 지단백 입자 크기의 분포

임효영,김인숙,승기배,강동헌,전두수,장기육,박준철,이수영,홍순조,최규보 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.8

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.

3차원 두부방사선규격사진의 정확성에 관한 연구

배기선,박수병,손우성 대한치과교정학회 1997 대한치과교정학회지 Vol.27 No.1

본 연구는 교정 임상에서 흔히 촬영되는 측모와 정모 두부방사선규격사진을 사용하여 3차원적인 두개안면 형태를 재현하였을 때 그 방법의 정확성을 고찰해 보고, 기존의 측모 두부방사선규격사진과 비교하여 어떠한 차이를 보이는지 알아보고자 하였다. 이를 위해 두개안면 골격모형의 3차원 두부방사선규격사진을 형성하고, 선 계측과 각도 계측을 시행하였다. 여기서 얻어진 계측치들을 실제 계측치 및 측모 두부방사선규격사진에서의 계측치와 비교하여 다음과 같은 결론을 얻었다. 1. 3차원 두부방사선규격사진의 선 계측 평균 오차는 0.94±0.62mm, 평균 확대율 100.31±0.91% 이었으며 실제 계측치와 차이를 보이지 않았다(α=0.1). 2. 측모 두부방사선규격사진은 선 계측에서 평균 오차 6.44±1.48mm, 평균 확대율 106.99±1.45%로서 하악체를 제외한 모든 선 계측에서 확대를 보였다(P<0.005). 3. 3차원 두부방사선규격사진에서의 각도 계측은 평균 오차 1.22±0.82°, 평균 확대율 105.72±12.07%로서 실제 계측치와 차이를 보이지 않았다.(α=0.1). 4. 측모 두부방사선규격사진은 평균 오차 1.70±0.94°, 평균 확대율 106.35±15.70%으로 실제 계측치와 차이를 보이지 않았다(α=0.1). Conventional cephalometrics have inherent errors because their evaluation is performed in two-dimension for three-dimensional object. To compensate these errors, three-dimensional cephalograms - derivation of three-dimensional data from conventional lateral and postero-anterior cephalograms - were developed. In this study, the accuracy and precision of three dimensional cephalograms were determined by means of 10 linear and 12 angular measurements on 36 acrylic skull models and by the comparison of conventional lateral cephalograms. The results were as follows : 1. Mean difference between three-dimensional cephalograms and actual models in linear measurements was 0.94±0.62mm and mean rate of magnification of three-dimensional cephalograms was 100.31±0.91%. There were no statistically significant differences between three-dimensional cephalograms and actual models in linear measurements(α=0.1). 2. Mean difference between conventional lateral cephalograms and actual models in linear measurements was 6.44±1.48mm and mean rate of magnification of lateral cephalograms was 106.99±1.45%. There were statistically significant differences between lateral cephalograms and actual models in linear measurements(P<0.005). 3. Mean difference between three-dimensional cephalograms and actual models in angular measurements was 1.22±0.82° and mean rate of magnification of three-dimensional cephalograms was 105.71±12.07%. There were no statistically significant differences between three-dimensional cephalograms and actual models in angular measurements(α=0.1). 4. Mean difference between conventional lateral cephalograms and actual models in angular measurements was 1.70±0.94° and mean rate of magnification of lateral cephalograms was 106.35±15.70%. There were no statistically significant differences between lateral cephalograms and actual models in angular measurements(α=0.1). There were similarity between three-dimensional and lateral cephalograms in angular measurements.

북한에 진출하는 한국기업의 투자 효율화 방안

배수진 啓明專門大學 産業開發硏究所 2001 啓明硏究論叢 Vol.19 No.1

지난 몇 년 동안 원화 절상, 노사갈등과 부의 적정배분 요구에 따른 임금인상, IMF로 인한 국제 원자재의 가격 상승 등은 산업 경쟁력을 파괴해 버렸다. 수출은 급격히 하락하고 노동 집약산업은 임금 우위국인 아시안 제국가들에게 이전되고 있다. 따라서 우리 기업들은 직접 투자 대상국을 선정하여 경제적 어려움을 해결해야 한다. 북한에 진출한 우리 나라 기업의 문제점을 해결하고 투자를 효율적으로 대응하기 위해서는 북한에 대해 많은 연구를 해서 대처해야 하겠지만 다음과 같은 방안을 강구하는 것이 좋을 것이다 1. 종합상사와 제조기업 또는 대기업과 중소기업이 공동으로 합작 투자사업을 추진함으로써 시너지 효과를 올릴 수 있어야 한다. 2. 정부의 정책적 추진방안이 모색되어야 한다. 결론적으로 우리의 선진기술과 그들의 천연자원과 노동력을 결합하면 우리 기업은 성공할 수 있는 좋은 투자 대상국이 될 수 있다. For the last few years the industrial competition was deeply damaged by the several factors such as wage increase, IMF policy, won currency evaluation, and price hike of raw materials in the international market. Exports were greatly decreased and the labor-intensive industries are moving toward other Asian wage superior countries. The Korean business firms are making a direct investment so as to get over the economic difficulties they have. The aim of this study is to analyze the investment environment and its problems in order to provide the firms which will advance into North Korea with the effective way of investment. Those suggestions are as follows : 1. We should make efforts to achieve synergy effects based on mutual compliment by a joint venture of a general trading, a manufacturing company, a large enterprise, or a small and medium enterprise. 2. A drive plan of policy must be led by the government. Finally. we come to a conclusion that North Korea would be a good partner of investment if we would combine their natural resources and labor with our advanced technologies

수도권에서 아황산가스의 황산염으로 전환시 각 과정의 상대적 기여도

배수야,김용표 한국대기환경학회 2003 한국대기환경학회지 Vol.19 No.4

The major conversion processes of SO₂ to sulfate arc reactions in gaseous, aqueous phase and on dust surface. Using the measurement data in Ganghwa, the background area of metropolitan Seoul Area, the relative contiribution of the conversion processes am estimated. Generally, aqueous cloud is the most important conversion path followed by dust surface. gas, and aqueous aerosol. Importance of conversion on dust surface increases for the dust storm period. The total conversion rate values over the metropolitan Seoul area are between 1.5 and 8.8×10^(-11) mole m_(-3) air.

세탁기시장에서의 소비자피해 실태 및 소비자요구에 관한 연구

배순영,박수경 기전여자대학 1996 論文集 Vol.16 No.-

This study examined the consumer needs on an electric washing machine market. For this purpose, survey was conducted using questionaire. The data included 321 women living om Seoul. Statistics analyses were conducted using frequencies, percenties, mean, ANOVA. The major findings were consumers require improvement about economizing function of washing machine and a catalog and a sales networks. Therefore, economizing function should be better and a catalog should be detailed and a discount store should be enlarge.

수술 후 통증조절을 위한 지속적 경막외제통 및 정맥내 자가조절법 2,510예에 대한 임상분석

배상철,곽수달,강규식 순천향의학연구소 1998 Journal of Soonchunhyang Medical Science Vol.4 No.2

Background: The efficacy and safety of continuous epidural analgesia(CEA) and intravenous patient-controlled analgesia(IV-PCA) for postoperative analgesia on hospital wards was studied. And then we started postoperateve pain management service using a continuous epidural analgesia and intravenous patient-controlled analgesia. Method: A retrospective study was performed to evaluate the effects of continuous epidural analgesia(CEA): 0.125% bupivacaine 100ml + morphine 5~7mg or clonidine 1800㎍ and intravenous patient-controlled analgesia(IV-PCA): normal saline 20ml + fentanyl 800~1000㎍ or nalbuphine 80~100mg, for postoperative pain relief of 2,510 surgical patients who received general-epidural or epidural-regional anesthesia. Anesthesia records, patients charts, and pain control records were received and classified according to: age, sex, department, operation site, degree of pain relief by CEA and IV-PCA, and side effects(including nausea, vomiting, pururitis, urinary retention and respiratory depression). Results: 1) The study included CEA were 1,022(40.7%) patients and IV-PCA were 1,488(59.3%) patients. 2) From the total of 2,510 patients, there were 2,253(89.8%) female patients; 2,078(82.8%) patients were from Obstetrics and Gyneco]ogy. 3) In the operation site, lower abdomen were 2,053(81.8%), lower extremity were 206(8.2%), upper abdomen 136(5.4%) were order of decreasing frequency. 4) Ninety one percent of the patients experienced mild or no pain in the postoperative course. 5) There were most common complication is the nausea and vomiting. 6) There were eight cases of respiratory depression. The course of treatment consisted of: cesation of infusion, and then administration of oxygen and intravenous naloxone. Conclusions: According to our experiences, we conclude that CEA and IV-PCA is an effective, relatevely safe and highly satisfactory method for postoperative pain management.

Rebounder 運動負荷後 恢復期의 心肺機能의 變化

裵玉錫,黃樹寬,金亨鎭,朱永恩 慶北大學校 醫科大學 1982 慶北醫大誌 Vol.23 No.2

20∼22歲의 男子大學生 61名을 硏究對象으로 하여 選手群(21名)과 非選手群(40名)으로 區分하였다 運動負荷는 rebouner에 垂直뛰기를 一分間에 80回程度로 3分동안 實施했으며, 運動後 恢復期 1, 3, 5, 10 및 20分에서 心搏數, 血壓, 呼吸數의 恢復樣相을 觀察하였다. 이로써 체력단속이 恢復期의 心肺機能에 미치는 影響을 分析하고 나아가서 恢復期의 心肺反應이 體力을 評價하는 指標가 될 것인가를 알고자 試圖한 本 硏究結果를 要約하면 다음과 같다. 安靜狀態의 心搏數는 選手群이 非選手群에 比해서 有意하게 낮았으며 血壓 및 呼吸數는 別 差異가 없었다. 運動負荷後 心搏數의 恢復은 選手群은 恢復 1分에 86.4±3.22回로서 非選手群의 118.0±2.81回에 比해 有意하게 낮았고, 兩群 모두 恢復初期에는 急速한 恢復을 보였으며 選手群이 非選手群에 比해 繼續有意하게 낮은 값으로 빠른 速度로 恢復되었다. 運動負荷後 收縮期血壓의 恢復樣相은 選手群이 非選手群보다 繼續 낮은 값으로 恢復되었으며, 特히 恢復 1分에 選手群은 161.2±1.78mmHg로 非選手群의 174.1±3.41mmHg에 比해 有意하게 낮았다. 兩群 모두 恢復初期에 急速히 恢復하여 恢復10分에는 安靜狀態로 恢復되었다. 그리고, 擴張期血壓은 非選手群은 期動後 安靜狀態보다 有意하게 높았으며, 選手群은 오히려 安靜狀態보다 낮았다. 平均動脈壓은 恢復初期에 選手群이 非選手群보다 높은 값으로 恢復되었으나 恢復10分부터는 거의 같은 값으로 恢復되었다. 脈壓은 選手群이 非選手群에 比해 繼續 有意하게 낮은 값으로 恢復되었다. 運動負荷後 呼吸數는 恢復 1分에 選手群에서는 27.1±1.23回로 非選手群의 35.5±1.17回에 比해 有意하게 낮았고, 兩群 모두 恢復 1,3分에 急速히 恢復되었으며, 選手群이 非選手群에 比해 繼續 有意하게 낮은 값으로 恢復되었다. 本硏究結果를 綜合하면 rebounder 運動負荷後 選手群의 心搏數, 血壓 및 呼吸數가 非選手群에 比해 有意하게 낮았으며, 그 恢復速度도 빨랐다. 특히 心搏數는 選手群과 非選手群 사이에 恢復初期부터 恢復 20分까지 繼續 有意한 差異를 나타낸 점은 體力을 客觀的으로 評價하는 重要한 資料가 될 것으로 思料되는 바이다. Sixty-one male subjects aged between 20-22 years were divided into the athletic and non-athletic groups. Exercise was performed as vertical jump on a rebounder at 80 times per min for 3min. The heart rate, blood pressure, and respiratory rate were measured at 1, 3, 5, 10, and 20min after exercise in an effort to analyze the effect of the physical training on the cardiopulmonary function during the recovery period, and to find out if the cardiopulmonary responses during recovery period can be an index of physical fitness. The results are summarized as follows. In resting state, the heart rate was significantly lower in athletes than in non-athletes, while blood pressure and respiratory rate showed no significant difference between the two groups. The heart rate at 1min after the exercise was 86.4±3.22 in athletes which was significantly lower than 118.5±7.85 in non-athletes. The heart rate at the initial stage after exercise showed a rapid recovery in both groups. In athletes, it showed a rapid recovery to reach a significantly lower level than that of non-athletes. The systolic pressure was lower in athletes than in non-athletes throughout the recovery period. In particular, systolic pressure at 1min after the exercise was 161.2±1.78 mmHg in athletes which was significantly lower than 174.1±3.41mmHg in non-athletes. Systolic pressure at initial stage after the exercise showed a rapid recovery, and the resting value was retored in 10 min in both groups. Diastolic pressure during the recovery period was significantly higher in non-athletes and lower in athletes than the resting level.

표고 버섯 중의 Branched chain amino acid Aminotransferase 의 분리정제 및 그 성질에 관한 연구

배강규,민태진,이수용 동국대학교 자연과학연구소 1987 자연과학연구 논문집 Vol.7 No.-

표고버섯중의 branched chain amino acid aminotransferase〔BCAT(EC 2,6,1,42)〕를(NH₄)₂SO₄ 분별침전, DEAE-cellulose column chromatography 및 sephades G-150겔 여과로 정제하여 그 특성을 조사하였다. 이 효소의 최적 pH는 8.5, 최적 온도는 36℃였고, 20℃이하에서 30분동안 열에 안정하였다. 이효소의 분자량은 69,000dalton이었으며, 산 가수분해하여 아미노산을 분석한 결과 18종의 서로 다른 아미노산들로 구성되어 있었다. 이 효소는 가지달린 아니노산인 L-valine, L-leucine 및 L-isoleucine에 대해서 특이성을 보였으며 phenylamine, potassium cyanide, phenylhydrazine, N-ethylmaleimide 및 p-chloromercuribenzoate에의하여 효소활성이 억제되었다. 또 한, L-leucine, a-ketoglutarate 및pyridoxal-5-phosphate에대한 이 효소의 Km값은 각 각 2.40mM, 2.98mM 및 1.74uM이었다. Branched cnain amino acid aminotransferaase 〔BCAT (EC 2.6.1.42)〕was purified by ammonium sulfate saturation. DEAE-cellulose column chromatography and sephadex G-150 gel filtration in Lentinus edodes(Berk.) Sing. Optimum pH and temperature were found to be 8.5 and 36℃, respectively. Apparent molecular weights of this enzyme was estimated 69.000 dalton by HPLC and SDS-PAGE. It showed activity toward L-leucine, L-isoleucine and L-valine as a substrate. It was ingibited by hydroxylamine, potassium cyanide, phenylgydrazine. N-ehylmaleimide, p-chloromercuribenzoate (CMB). cupric acetate and mercuric chloride. The Km values of this enzyme were determined to be 2.40mM for leucine, 2.98mM for a-ketoglutarate and 1.74μM for pyridexal-5- phospate, respectively.