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.

CONVERGENCE OF APPROXIMATING FIXED POINTS FOR MULTIVALUED NONSELF-MAPPINGS IN BANACH SPACES

Jung, Jong Soo The Kangwon-Kyungki Mathematical Society 2008 한국수학논문집 Vol.16 No.2

Let E be a uniformly convex Banach space with a uniformly $G{\hat{a}}teaux$ differentiable norm, C a nonempty closed convex subset of E, and $T:C{\rightarrow}{\mathcal{K}}(E)$ a multivalued nonself-mapping such that $P_T$ is nonexpansive, where $P_T(x)=\{u_x{\in}Tx:{\parallel}x-u_x{\parallel}=d(x,Tx)\}$. For $f:C{\rightarrow}C$ a contraction and $t{\in}(0,1)$, let $x_t$ be a fixed point of a contraction $S_t:C{\rightarrow}{\mathcal{K}}(E)$, defined by $S_tx:=tP_T(x)+(1-t)f(x)$, $x{\in}C$. It is proved that if C is a nonexpansive retract of E and $\{x_t\}$ is bounded, then the strong ${\lim}_{t{\rightarrow}1}x_t$ exists and belongs to the fixed point set of T. Moreover, we study the strong convergence of $\{x_t\}$ with the weak inwardness condition on T in a reflexive Banach space with a uniformly $G{\hat{a}}teaux$ differentiable norm. Our results provide a partial answer to Jung's question.

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.

Periapical multilocular osteoporotic bone marrow defect

Jung, Yun-Hoa,Cho, Bong-Hae,Nah, Kyung-Soo 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.4

A case of osteoporotic bone marrow defect, which appeared as a well-defined multilocular radiolucency overlapping the roots of mandibular right second molar, was reported. On periapical radiograph, a daughter cyst-like radiolucency was seen at the anterior margin of the lesion making it difficult to rule out odontogenic keratocyst.

반복적인 실신 및 실신전환자의 기립경사 검사시 뇌혈류 변화

조수진,김준수,이광호,정진상,송희정,이상철,서정돈,이원로 대한신경과학회 1999 대한신경과학회지 Vol.17 No.3

Cardinal Andrew YEOM Soo-jung

YEOM Soo-jung 신학과사상학회 2018 가톨릭 신학과 사상 Vol.- No.81

유치거리 분석을 통한 도시공원의 적정배치에 관한 연구

류연수,나정화,도후조 慶北大學校農業科學技術硏究所 2002 慶北大農學誌 Vol.20 No.-

The purpose of this study is to analysis of disposition distance of city park for the plan of suitable arrangement of city park based on the date examining Daegu Metropolitan City. The results of this study are as follows. 1) The result of analysis of population density as the case of districts, it appeared highly in city center area which Seo-Gu district and Nam-Gu district besides Jung-Gu district. However, it apperared in a low Buk-Gu district, Dong-Gu district and Salseong-Gun. 2) The result of analysis of population density as the case of regions, it appeared very highly Joukjun-Dong of Dalseo-Gu district(31,554per/㎢), Naedang-Dong of Seo-Gu district(29,922per/㎢). However it appeared in a low YeugaoMaen(85per/㎢) and Gachang-Maen(94per/㎢) of Dalseong-Gun. The regions where the population density is high have very low green space and live a lot of low income layer. 3) The result of analysis of disposition distance, in the case of children park, it appeared an intensive distribution in Dongcheon-Dong and Guam-Dong of Buk-Gu district, Whanggm-Dong and Dusan-Dong of Suseong-Gu district, Sangin-Dong and Yeongasn-Dong and Walsung-Dong of Dalseo-Gu district. however, it appeared in a low in Jung-Gu district. The case of urban park of the neighboring area, it appeared the most in Dalseo-Gu district except 2 parks in Jung-Gu district, the case of urban park of the walking area, it apperared in equality in city. 4) In conclusion, the area have population density and lots of low income layer, is in out of disposition distance should be considered in first for city park plan.

The Effect of Train Acceleration on the Pantograph Dynamics

Kim, Jung Soo Research Institute of Science and Technology HONGI 2005 Hongik Journal of Science and Technology Vol.9 No.-

The dynamic characteristics of the pantograph are evaluated by conducting a test run in which signals from accelerometers and load cells attached to the various parts of the pantograph assembly are evaluated. By analyzing these signals, it has been found that the dynamic characteristics of the pantograph are strongly influenced by the train speed, with the major frequency components arising from the train traversing the span spacing and the 8.5 Hz component originating from the panhead resonance. The train acceleration is found to have significant influence on the span passing frequency but negligible effect on the resonant response.

병원에서 사용된 백신양으로 평간한 예방접종 실태

김정수,백용수,정문현,이진수,오경선 대한감염학회 2008 감염과 화학요법 Vol.40 No.3

Background : Studies on immunization in Korea mainly focus to the coverage rates in recipients. The attitudes of health-care providers regarding immunization are rarely evaluated. Therefore, to assess the pattern of vaccine administration by health-care personnel, the vaccine consumption in a university hospital was investigated. Materials and Methods : The vaccine consumption in a university hospital during 2 months (September and October) in 2 years (2002 and 2007) was evaluated. September is representative of months when influenza vaccine is not available, whereas October is representative of months when influenza vaccine is available. These monthly data were summarized by departments and vaccines. Results : Vaccine consumption over the 5-year period increased primarily because of the increased use of the influenza and tetanus-diphtheria (Td) vaccines in adults. In 2007, the most frequently administered vaccine during the influenza season was the influenza vaccine, followed by the Td vaccine. In the same year, the Td vaccine was the most frequently administered vaccine during the non-influenza season. Compared to 2002, there was a marked increase in the use of the hepatitis A virus (7-fo1d), Japanese encephalitis (6-fo1d), and pneumococcal polysaccharide (3-fold) Vaccines in 2007; the Td, meningococcal, and pneumococcal protein-conjugated vaccines were not available in 2002. In adults, pneumococcal vaccination was increasingly prescribed concomitant with the increased influenza vaccination: a similar trend was not observed in children. The use of vaccines in most departments was confined to the influenza vaccine, and the majority of Td vaccine was consumed in the emergency department. As compared to the internal medicine and family medicine departments, fewer vaccines were prescribed by the neurology, surgical, and minor specialty departments, especially in the non-influenza season. Conclusion : Although vaccine consumption increased during the 5-year period, the increase was attributed to the increased consumption of the influenza vaccine. Promotion and education regarding the use of non-influenza vaccines are needed. 배경 : 국내에서 백신 사용은 접종을 받은 사람에서만 조사가 되었고, 예방접종 제공자에서 조사가 적었다. 앞으로 백신 접종률을 높이기 위해서는 접종자에 대한 연구도 있어야 하며, 병원 단위에서 백신 사용 양상을 알기 위해 대학병원에서 백신 사용량을 조사하였다. 재료 및 방법 :2002년과 2007년의 9월과 10월에 약제부에서 사용된 백신 양을 조사하였다. 9월은 인플루엔자 백신이 없는 달을 대표하는 달이고 10월은 인플루엔자 예방 접종이 가능한 달을 대표한 것이다. 월별 백신 소모량을 과별, 백신별로 정리를 하였다. 결과 : 2002년에 비해 2007년에는 백신 사용량이 1.6배 증가했으며, 인플루엔자 백신과 Td의 사용 증가가 주요 이유였다. 인플루엔자 백신 접종 시기에는 인플루엔자 백신 사용량이 제일 많았고, 두 번째 많이 사용되는 백신은 2002년에는 B형 간염 백신이었고 2007년에는 Td였다. 성인에 서는 인플루엔자 백신 사용과 함께 폐렴사슬알균 백신 사용량이 늘었지만 소아에서는 이런 경향이 보이지 않았다. 인플루엔자 백신 접종 시기인 10월에는 소아과에서 사용보다 비소아과에서 백신 사용량이 더 많았다. 과별로 보면 대부분 과에서 인플루엔자 백신이 주로 사용되었고, 응급실에서는 Td만이 사용되었다. 신경과와 재활의학과, 외과계열, 소수과에서 사용이 적었다. 결론 : 예방접종이 5년 사이 증가하였으나 인플루엔자 백신에 국한된 양상을 보였다. 인플루엔자 백신과 파상풍-디프테리아 백신뿐만 아니라 다른 백신에 대한 홍보가 필요하다.

연작업자들에서의 δ -aminolevulinic acid dehydratase 유전형질의 다형성이 신기능에 미치는 영향

안익수,황보영,김용배,리갑수,이성수,장봉기,함정오,안규동,이병국 순천향대학교 산업의학연구소 2001 순천향산업의학 Vol.7 No.1

δ-aminolevulinic acid hehydratase (ALAD) is a polymorphic enzyme that has two alleles, ALAD1 (ALAD1-1 as phenotype) and ALAD2 (ALAD1-2 or ALAD2-2 as phenotype). ALAD genotype has been reported to modify the toxicokinetics of lead. To investigate the influence of ALAD genotype polymorphism on renal function in lead workers, author studied 1022 male lead workers and 149 non lead workers in the same industries. For the cross-sectional renal function indices, blood urea nitrogen (BUN), serum creatinine, uric acid and total protein were selected. Blood lead and blood zinc protoporphyrin were also measured as indices of lead exposure. Information on weight, age, job duration, smoking & drinking history were collected. Following results are as follows: 1. Whereas the mean (standard deviation) of blood lead and blood ZPP of lead workers were 27.2±12.5 ㎍/㎗ and 57.7±37.8 ㎍/㎗, those of non-lead workers in the same premises were 14.9±6.5 ㎍/㎗ and 44.6± 15.8 ㎍/㎗ respectively. The difference of mean blood lead and blood ZPP between two groups were statistically significant. 2. Whereas the prevalence of the variant allele, ALAD2 in 1022 lead workers was 10.2 %, the prevalence of that in 149 non-lead workers was 7.4 %. But there was no difference of prevalence between two groups. 3. The mean±standard deviation of blood lead of subjects with ALAD1 was 25.5± 12.7 ㎍/㎗ and was slightly lower than that of subjects with ALAD2 (26.5±10.9 ㎍/㎗), and the mean±standard deviation of blood ZPP of subjects with ALAD1 was slightly higher than that of subjects with ALAD2 (56.7±37.3 ㎍/㎗ vs 48.9±18.6 ㎍/㎗). But the differences of blood lead and blood ZPP between two genotypes were not statistically significant. 4. There were no differences of cross-sectional renal function indices (BUN, serum creatinine, uric acid and total protein) either by lead workers and non-lead workers or two genotypes. 5. In multiple regression analysis of ALAD genotype on BUN after controlling for possible confounders (sex, weight, job duration, smoking and drinking status), the mean of BUN in ALAD2 subjects was 0.629 ㎎/㎗ lower than ALAD1 subjects with a weak statistical significance (p=0.07). But in logistic analysis of ALAD genotype on median value of BUN revcaled that subjects of ALAD2 genotype were 32% less likely to have median value or more of BUN than subjects of ALAD1 with odd ratio of 0.618 (95% confidence interval 0.411-0.920). 6. In multiple regression analysis of ALAD genotype on serum creatinine after controlling for possible confounders (sex, weight, job duration, smoking and drinking status), the mean of serum creatinine in ALAD2 subjects was 0.0271 ㎎/㎗ lower than ALAD1 subjects with statistical significance (p=0.02). On the other hand, in logistic analysis of ALAD genotype on median value of serum creatinine revealed that subjects of ALAD2 genotype were 30% less likely to have median value or more of scrum creatinine than subjects of ALAD1 with odd ratio of 0.700 (95% confidence interval 0.442-1.080). With the above results, it was found that the variant allcle, ALAD2 appeared to modify the association of lead and renal function and ALAD2 genotype may be supportive for the protective effect of lead.