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.

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.

A Genealogical Approach to the Incoterms Rules and Revised Incoterms 2010

Jae‐,Hwan Chung,Bong‐,Soo Lee 한국무역학회 2013 Journal of Korea trade Vol.17 No.2

Incoterms have provided a set of rules that the global trade community can use for the interpretation of shipping terms. Always viewed from the perspective of the seller’s delivery obligation, Incoterms focus on the responsibility for the risk of loss or damage to the goods sold, division of transportation and customs‐related costs between the seller and buyer, and the obligation to execute certain functional activities related to the movement of the goods. The ICC has consistently attempted to update Incoterms in a way that keeps pace with the evolution of business practices. The ICC recently published the new listing of terms, which hints at some of the significant changes ahead in the new publication. It is not certain how the Incoterms 2010 have been used in practice, so it is difficult to find out related problems. Therefore, those who are unwilling to use Incoterms 2010 are free to choose Incoterms 2000 or other trade terms. However, this kind of practice can cause a conflict because of differences in the interpretation of trade terms in international trade. It would be desirable to use Incoterms 2010 based on the revised Incoterms 2000. It is still unclear how predominantly Incoterms 2010 will be used in international trade. Of course, it is necessary to keep updating trade terms based on a deeper analysis on the matters associated with the Incoterms rules, and maintain an understanding of contemporary changes. In this context, this thesis aimed to investigate the historical background of the Incoterms rules and find out how t

Consideration of Diluents Selection and Input Amounts of the Hunter Process for Tantalum Production

Jae‑Jin Sim,Sang‑Hoon Choi,Yong‑Kwan Lee,Sung Gue Heo,Taek‑Soo Kim,Seok‑Jun Seo,Kyoung‑Tae Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

Tantalum (Ta) is a heavy refractory metal with an atomic weight of 180.95 g/mol, a density of 16.6 g/cm3, and a high meltingpoint of 3017 °C. With its refractory characteristics, it shows excellent chemical and physical stability as well as corrosionand heat resistance at elevated temperatures. The demand for Ta metal and related compounds is increasing with the expansionof the electronics and chemical industries. The Hunter process was proven to be effective in producing Ta powder in1953. Hunter proposed a method in which potassium heptafluorotantalate (K2TaF7) was reduced by sodium (Na). Thus far,this process has been the primary commercial method to produce Ta powder. In this study, quantitative differences wereanalyzed for diluent selection. Additionally, consideration was given to changes in the caloric value depending on the inputamount of diluents. Finally, the optimum material input and the properties of the prepared Ta were analyzed. Stoichiometricratios of K2TaF7(1 mol), NaCl (6.2–6.7 mol), Na (5–7 mol) were weighed, to perform a metallothermic reduction reaction. After the reaction, the tantalum powder was recovered and the flush process was carried out. After that, it was dried in avacuum atmosphere. Physical properties such as oxygen concentration, PSA, ICP-OES, and XRD of powder were conductedto evaluate the characteristics of Ta powder that was finally manufactured.

QT연장 증후군 환자에서 Head-Up Tilt Test에 의해 유발된 Torsades De Pointes 1례

전익수,차태준,김길수,김동완,김규종,김찬욱,김성만,주승재,이재우 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.8

Characterization of Antihypertensive Angiotensin I-Converting Enzyme Inhibitor from Recombinant E. coli

Kim, Jae-Ho,Jeong, Seung-Chan,Lee, Dae-Hyoung,Lee, Jong-Soo 배재대학교 자연과학연구소 2005 自然科學論文集 Vol.16 No.1

안지오텐신(ACE) 저해제는 항고혈 효과를 갖고 있으므로 오랫동안 고혈압의 예방이나 치료에 이용되어 왔다. 본 연구는 재조합 대장균으로부터 새로운 ACE 저해제를 생산하고 정제하며 나아가 이들이 구조-기능 관P를 규명하기 위해 수행되었다. Saccharomyces cerevisiase의 ACE 저해 펩타이드 유전자를 함유하고 있는 재조합 pGEX-4T-3을 대장균 BL21(DE3)로 형질전환 시켰다. 재조합 pGEX-4T-3을 갖고 있는 대장균 BL21(DE3)로부터 생산된 Glutathione-s 전이효소 (GST) 융합 단백질을 얻어서 그중 ACE저해 펩타이드를 Sephadex G-25 컬럼 크로마토그래피로 정제하였다. 정제된 ACE 저해 펩타이드는 타이로신-아스파틱엑시드-그리신-글리신-발린-패닐알라린-아르기닌-발린-타이로신-트레오닌의 서열을 가진 새로운 decapeptide이었고 ACE에 대하여 경쟁적으로 저해하였다. The angiotensin I-converting enzyme (ACE) inhibitor has anti-hypertensive effects and has long been used as prevention or remedy of hypertension. This study were carried out to produce and purify a new ACE inhibitor from recombinant E. coli and further elucidate its structure-function relationship. Recombinant pGEX-4T-3 containing ACE inhibitory peptide gene of Saccharomyces cerevisiae was transformed into E. coli BL21(DE3). Glutathione-S transferase (GST) fusion protein from E. coli BL21(DE3) harboring the recombinant pGEX-4T-3 was obtained and the ACE inhibitory peptide was purified with Sephadex G-25 column chromatography. The purified ACE inhibitory peptide was a novel decapeptide with sequence Tyr-Asp-Gly-Gly-Val-Phe -Arg-Val-Tyr-Thr which shows very low similarity to the other ACE inhibitory peptide sequence. The purified ACE inhibitor competitively inhibited ACE.

複合生藥製劑의 止血作用및 摘出子官筋에 미치는 影響(第4) : 壽脾煎 및 歸脾양에 대하여 On Soo-Bi-Jeon and Kwi-Bi-Tang

殷載淳,李東熙,黃甲洙 又石大學校 1990 論文集 Vol.12 No.-

These experiments were conducted to investigate the pharmacological difference between Soo-Bi-Jeon and Kwi-Bi-Tang extract,, clinically used in gynecology, on the hemostasis and the contractile force of the isolated uterine muscle. For this purpose, the effects of the extracts on the bleeding time in mouse tail and prothrombin time in vitro were estimated. Forthermore, its activity on the isolated uterine muscle in rats were investigated. The results obtained were as following; The bleeding time and prothrombin time were significantly shortened compared with the control group in all samples, The uterotonic action produced by Kwi-Bi-Tang(Sample II), Sample III and IV (the same component crude drugs between not blocked by atropine (10^(-7)M) and cyproheptadine (10^(-7)M). but inlhibited by pretreatment of verapamil (10^(-7)M). On the oter hand, Soo-Bi-Jeon(Sample I) extract relaxed the uterine muscle.

관상동맥내 스텐트 삽입후 발생한 관상동맥류 2례

제인수,허민영,문치숙,이재호,정수룡,조길현,이영민,김대경,김두일,김동수 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.3

Coronary artery aneurysms are detected with increasing frequency because of the routine use of coronary angiography in the diagnosis and management of coronary artery disease. Although some coronary artery aneurysms are congenital or inflammatory, most are atherosclerotic. The prognosis of atherosclerotic coronary artery aneurysm may depend on the morphology of the aneurysm or the presence of coexisting obstructive disease. Coronary artery aneurysms have been also reported to occur after ballon angioplasty, directional athrectomy, laser angioplasty, and stent implantation with a frequency of 2% to 4%. The long-term outcome of post-intervention coronary artery aneurysm is unknown. We report two cases of the development of a coronary aneurysm 6 months after stent implantation as a treatment of severe obsructive coronary artery disease.

심장 이식 환자에서 발생한 Cryptococcus neoformans에 의한 뇌막염 2예 : The report of two cases

박재형,이윤정,강수진,정영훈,장진석,정준원,최상호,김순종,김양수,김재중 대한화학요법학회 2001 대한화학요법학회지 Vol.19 No.3

최근 장기 이식과 관련된 면역억제제의 사용 빈도의 증가 및 후천성면역결핍증 환자의 증가 등으로 인해 기회감염이 증가되고 있으며, C. neoformans에 의한 감염도 증가되고 있다. 저자들은 심장이식 후 6개월이상 지난 환자에서 발생한 크립토코쿠스 뇌막염 2예를 경험하였는데, 한 예의 경우는 거대세포 바이러스 감염과 함께 C. neoformans의 전신적 파급성 감염의 형태로 나타났었고, 폐에 A. fermigatus에 의한 감염이 같이 병발된 경우였다. 이들은 모두 경미한 증상만을 호소하였고, 뇌척수액 검사를 통해 진단받았으며 liposomal amphotericin B와 경구용 fluconazole을 사용하여 완치되었기에 문헌고찰과 함께 보고하는 바이다. Cryptococcal meningitis is a subacute or chronic mycotic infection caused by Cryptococcus neoformans and it is a second most common central nervous system (CNS) infection in organ transplant patients. The recent rise in incidence of the disease can be attributable to the wide use of immunosuppressive agents in organ transplant patients, the advent of acquired immunodeficiency syndrome (AIDS) patients and increased use of chemotherapeutic agents. We report two cases of cryptococcal meningitis after cardiac transplantation. Their symptoms were not typical and neurologic examination was nonfocal. One patient had disseminated cryptococcal infection and invasive pulmonary aspergillosis, it might be assodated with cytomegalovirus infection. They were diagnosed by cryptococcus latex agglutinin test and culture study with cerebrospinal fluid and treated with liposomal amphotericin B and oral fluconazole without any neurologic defects.

Magnetic resonance images of ameloblastoma

Kim, Jae-Duk,Kim, Jin-Soo 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.4

Purpose : To classify and describe the characteristic features of MRI of some ameloblastoma variants. Materials and Methods : The MR images, CT images, and panoramic radiographs in 5 cases were retrospectively examined as follows. First, the contents of ameloblastomas were devided into two portions of either solid or cystic components on the basis of MR signal intensities. The signal intensity within the solid or cystic portions was classified as homogeneous or heterogeneous. Next, the characteristic internal feature of the lesion on T1W1 or T2WI was described. The signal intensities were classified into low, intermediate, slightly high, high, and strong high signal intensity. Results : Unicystic lesion showed homogeneous high signal intensity (SI) on T2W2 and the rim enhancement of the surrounding area including the mural nodule and the thick wall except the central portion on Gd-T1W1 Solid type revealed heterogeneous and high SI area with strong high SI area on T2W2. On Gd-T1W1, the area corresponding to the low signal spot on T1W1 and the strong high signal spot on T2W1 showed low SI. Hybrid type showed slightly enhanced capsular structures and low SI for the round bony septa and the areas connecting the mixed and cystic lesions on T2W1 and Gd-T1W1. Conclusion : MRI could easily assess the relationship between the mixed and cystic findings in ameloblastoma.