Characterization and Property Evaluation of Ti‑Based Target Materials and Their Nitride Nano‑composites Coating Layers

Jeong‑Han Lee,Hyun‑Kuk Park,장준호,Ik‑Hyun Oh 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

This study formed a hard TiAlSiWN coating layer using Ti, Al, Si and W raw powders that were mechanically alloyed andrefined. The TiAlSi and TiAlSiW coating targets were fabricated using a pulse current activated sintering process in a shorttime with the optimal sintering conditions. The optimized sintering condition was obtained by controlling process parameterssuch as temperature, pressure, heating rate and pulse ratio (on/off). The coating targets were successfully deposited onthe WC substrate to form the TiAlSiN and TiAlSiWN nitride nano-composite structures by an arc ion plating process andalso, their coating layers were compared according to the addition of W element. The microstructures of the nitride nanocompositecoating layer were analyzed, focusing on the distribution of the crystalline phases, amorphous phases (Si3N4),and growth orientation of the columnar crystal depending on the addition of W element. The mechanical properties of thecoating layers were exhibited a hardness of approximately 3000 kg/mm2 and adhesion of about 117.77 N in the TiAlSiN. Inparticular, the TiAlSiWN showed excellent properties with a hardness of more than 4300 kg/mm2 and an adhesion of about181.47 N, respectively.

Effect of Mechanical Alloying on the Microstructural Evolution of Al60Cr30Si10 Alloys Processed by Spark Plasma Sintering

Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5

In this study, Al, Cr and Si fine powders were alloyed by planetary ball milling to investigate their microstructural evolution,following their mechanical alloying behavior. The formation of Al(Cr) supersaturated solid solution by the Cr grainsembedded in Al-matrix, which contributed substitutional structure is discussed in relation to their structural evolution inaccordance with the distortion of a crystal lattice. The compacts of Al–Cr–Si alloys were prepared by rapid sintering withina short time by dense consolidation above the density of 99.9% as the formation of intermetallics, except in the case of thedistribution of single-phases induced by the Al-melting. The formation behavior of intermetallics was dominated by dependenceon the structures of the milled-powder and subsequent sintering temperature. To estimate the consolidated behaviorsof compacts, various approaches derived from TEM and XRD analysis were taken to obtain microstructural evidences ofthe inter-diffusion, following the presence of thermally stable intermetallics.

Influence of Phase Composition in TiAlSiN Hard Coatings on the Evolution of Structure and Mechanical Properties

Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.3

The aim of this study is to investigate the structural evolution and mechanical properties of TiAlSiN coatings when processedby the arc ion plating method. To form a hard coating, Ti, Al, and Si powders were mechanically alloyed by planetary ballmilling; the powders were then densely compacted during a rapid sintering process into a ternary system coating, i.e. TiAlSi. The evolution of the structural phase from a powder to a compact material is dominated considerably by phase states suchas a supersaturated solid solution or intermetallic compounds. In the case of coating layers, the factors that determine thestructural evolution are associated with the phase stability of the nano-crystalline structure that in turn is associated withthe Ti/Al composition ratio. Motivated by this, we performed experiments to investigate the distribution of microstructures;the material’s binding energy, quantitative properties, transformation of crystal structure, and distribution of amorphous/crystalline were all recorded. In particular, the relationship between the physical and chemical properties during the coatingprocess is considered to be the dominant factor controlling the orientation and morphology of that zone (1, T, and 2). TheTiAlSiN coating layer was found to have hardness above 45 GPa and an adhesion above 100 N. In other words, understandingthe evolution and structure of TiAlSin helped us to produce a material with excellent properties that can be used as a hardcoating. Specifically, these properties were induced by a grain refinement of the nano-crystalline structure that correspondsto an increase in the silicon nitride contents.

Rapid Consolidation of WC‑ZrSiO4 Hard Materials by Spark Plasma Sintering: Microstructure, Densification, and Mechanical Properties

Jeong‑Han Lee,Ik‑Hyun Oh,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

Densely consolidated WC-based hard materials with 5–20 vol% ZrSiO4was fabricated by spark plasma sintering at 1400 ℃ ata constant heating rate of 70 ℃/min−1. To achieve mechanical alloying of WC-ZrSiO4, planetary ball milling was carried outfor 12 h, during which the brittle-brittle components (WC-ZrSiO4) became fragmented and their particles became refined. Itwas observed that certain, specific, non-isothermal sintering kinetics, such as apparent activation energy, sintering exponents,and densification strain, affected the densification behavior. The evolution of phase structure from powder to compact wasfound to be related the lattice distortion and micro-strain in the basal planes of WC. By examining the mechanical propertiesof the samples, it was that the added zircon content leads to enhanced fracture toughness (12.9 MPa m1/2) owing to thepresence of WC-ZrSiO4 in the cemented carbide. In fact, the microcrack propagation of the fracture passed through zirconfrom a transgranular to a ductile component (fcc) where the crack tips could be absorbed.

사람 갑상선자극호르몬 수용체를 발현하는 Chinese Hamster Ovary(hTSHR-CHO)세포를 이용한 자극형 갑상선자극호르몬 수용체 항체 활성 측정의 임상적 유용성

한희정,원진호,채수홍,김현진,송민호,김영건,노흥규 충남대학교 의과대학 지역사회의학연구소 2000 충남의대잡지 Vol.27 No.1

Detection of thyroid stimulating hormone receptor(TSHR) autoantibodies has clinical value in establishing the diagnosis of Graves ' disease, and in predicting its clinical course with high sensitivity and high specificity. Especially, TBII using radioreceptor assay has been widely used. Recently, for detecting thyroid stimulating antibody(TSAb), a sensitive method using human TSH receptor-transfected Chinese Hamster Ovary(CHO) cells has been developed and clinically used. The aims of this study are to determine the change and discrepancy of 2 TSHR autoantibodics in clinical course and to evaluate the correlation between 2 autoantibodies. We measured TSAb and TBII in 30 newly diagnosed and untreated patients and in 73 previously diagnosed as Graves ' disease and treated with antithyroid drug. Also we compared the changes of the antibodies in clinical course and correlation between 2 antibodies. Thes results are summarized follows. 1. In newly diagnosed patients, all of the 30 patients had positive TBII and/or TSAb. None of them had negative TBII and negative TSAb. And in newly diagnosed patients, mean TBII and mean TSAb values are 46.8% and 361%, respectively. In 73 treated patients mean values are 18. 7% and 196% each other. Therefore, newly diagnosed group has significant greater TBII and TSAb than antithyroid drug-treated group. 2. TBII was significantly different between euthyroid group and thyrotoxic group in antithyroid drug-treated patients, but TSAb was not. 3. TBII was sequentially decreased as increased medication duration, but TSAb was not shown sequential decrease as increased medication duration. 4. There was significant negative correlation between cumulative doses of antithyroid drug and TBII, but no significant correlation between cumulative doses and TSAb. 6. There was significant positive correlation between TBII and TSAb in total patients group and in antithyroid drug medication group, but not in newly diagnosed group. In conclusion, in Graves ' disease patients, detection of TSHR antibodies are clinical values in establishing the diagnosis and prediction of clinical course. A method detecting TSAb using hTSHR-CHO cells should be further studied for standardization of measurement, and for detecting the changes of TSAb in clinical course, long-term follow-up of patients are important.

위 전절제술을 받았던 환자에서 아급성 연합성 변성 1예

한정호,하현욱,이정석,송은향,김우정,김두응,최진영 건국대학교 의과학연구소 2000 건국의과학학술지 Vol.10 No.-

Subacute combined degeneration is a metabolic disorder of the spinal cord caused by vitamin B12 deficiency. A 72-year old man was admitted with weakness and tingling sensation of the bosh upper extremities. 9 years ago, he was diagnosed as having stomach cancer. So total gastrectomy with splenectomy was done at that time. The complete blood cell counts and morphology revealed megaloblastic anemia. Nerve conduction velocity study(NCV), electoromyography(EMG) and somatosensory evoked potentials(SEP) showed diffuse sensorimotor peripheral neuropathy. Magnetic resonance imaging(MRI) showed an increased T2-weighted signal, mild decreased T1-weighted signal, and slight contrast enhancement of the posterior columns of the cord in the cervical and upper thoracic spinal region. He was treated with vitamin B12 supplements and improved gradually. If abnormal sensation and muscle weakness was developed after gastrointestinal surgery, subacute combined degeneration should be considered in the differential diagnosis. We describe MRI findings of a typical case of subacute combined degeneration, which was induced by total gastrectomy.

석면함유 슬레이트 지붕 물받이 퇴적물 중 석면 섬유 함유율

임지현,한솔민,김현석,신유민,박시은,허정윤,김민영,장봉기 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

This study attempted to determine the degree of asbestos release from the aging slate roof by comparing the asbestos content in the slate roof rain gutter with a colored steel plate (tin plate) over the slate roof. Four slate roof houses located in Haengmok-ri, Asan-si, Chungcheongnam-do, and one house constructed with a colored steel plate on the slate roof were selected to collect the sediment of the roof rain gutter. The asbestos fiber content was calculated by a point counting method using a polarization microscope after pretreatment with conversion treatment and hydrochloric acid treatment. The average asbestos content of the four slate roof rain gutter were 1.89%. However, asbestos was not detected in the Slate covering roof rain gutter, which were constructed on the slate roof. Asbestos fiber content was the highest at 2.89% in the slate roof rain gutter installed in 1976, followed by 2.44% in 1953. From the above results, it is necessary to minimize secondary damage as asbestos fibers released from slate roof houses to the surrounding atmosphere or leaked from slate roofs as rainwater may cause soil pollution and seriously affect residents' health. Although covering with colored steel plates (tin plates) has been shown to prevent the leakage of asbestos fibers to some extent, it is believed that a policy alternative to remove the slate roof as soon as possible is needed to solve the fundamental problem.

‘병동 중심의 처치수가 산정지침 개발’ 등을 통한 간호업무 표준화 및 그 효과

한혜정,설미진,김영주,박소영,박아리스,문한경,이현영 한국의료QA학회 2009 한국의료질향상학회지 Vol.15 No.1

문제: 병동 처치수가 산정 부정확 및 누락으로 인한 부적절한 재고관리로 진료차질, 불필요한 업무발생 및 수익이 감소한다. 목적: 병동 처치수가 산정 정확화를 위한 업무 표준화 도구 및 시스템을 개발하여 적정 재고관리를 통한 수익증대 및 직무만족도를 향상시킨다. 의료기관: 서울시 종로구에 소재한 대학병원 질 향상 활동: 병동중심의 처치 산정지침 개발 및 수가물품의 적정재고 관리방안을 모색하였다. 개선효과: 병동중심의 처치수가 산정 지침서를 제작하여 업무표준화를 기하였음. 응급청구 품목 및 수량이 ’07년 대비 71%감소하고 타 병동 차용품목이 활동 전에 비해 61% 감소, 수량은 77% 감소함. 응급청구 총소요시간이 활동 전에 비해 ’07년 대비 77% 감소하고 타 병동 차용 총 소요시간이 61% 감소함. 전년 동기간 대비 수익이 4% 증가하였으며 또한 54병동과 보험 심사팀에서 직원들의 직무만족도가 향상되었다.

有機製品의 物性改質에 必要한 Silicone 架橋劑開發에 관한 硏究

韓貞璉,梁在乾,鄭一鉉,裵長淳 단국대학교 1985 論文集 Vol.19 No.-

Alkoxysilanes were synthesized by me alcoholysis of trichbromethyhilanc having trifunctional group with corresponding alcohols under sodium alkoxide or HCl acceptor. The yields of the products were more than 80%. It was found that the rate of the hydrolysis of ethoxysilane was faster than methoxysilane. Hexamethyldisilazanes were synthesized by the reaction of chlorotrimethylsilane with ammonia gas or ammonium liquid solution. The yields of the products were 86% and 26% respectively. As the results of hydrolysis of disilazanes prepared under acidic, neutral, and alkali solutions, the rate of the hydrolysis was increased with the order of alkali, neutral, and acidic solution. After synthesizing α,ω-dichloromethylsiloxane by the reaction of diethoxydimethylsilane with dimethyldichlorosilane, α,ω-dichloromethylsiloxanol with terminal hydroxyl group was prepared by the hydrolysis of the product. p-Phenylene-bis-dimethylchlorosilane was prepared through Grignard reaction of p-dibromobenzene with dimethyldichlorosilane, and then p-phenylene-bis-dimethyltydroxysilane was synthesized by the hydrolysis of p-phenylene-bis-dimethylchlorosilane. α,ω-dichloromethylsiloxane

오리부산물과 한약재를 이용한 추출액의 영양성분 및 중금속 노출에 대한 피해 완화 효과 : (Ⅱ) 중금속 노출에 대한 오리추출액의 피해 완화 효과 (Ⅱ) Damage Mitigation Effects on Heavy-metals Exposure of Peking-Duck By-Product Extracts

한종현,이우진,조성균,이미정,정미란,전정우,김운영,박성혜 동아시아식생활학회 2003 동아시아식생활학회지 Vol.13 No.4

This study was performed to investigate the effects of peking-duck extracts added with medicinal herbs(DJ) on the intoxication of heavy metals (Hg, Pb, Cd, As) in rats. Sprague-Dawley rats weighing 150±15g, were randomly assigned to 5 groups: basal diet only in normal control group(NCG); basal diet and heavy metals without DJ injection in heavy metal control group(HMC); basal diet, heavy metals and DJ(3㎎/㎖) injection in heavy metal low duck juice group(HMLD), basal diet, heavy metals and DJ(30㎎/㎖) injection in heavy metal middle duck juice group(HMMlD); basal diet, heavy metal and DJ(300㎎/㎖) injection in heavy metal high duck juice group(HMHD). Hg and As was injected by 50ppm and Cd and Pb by 25ppm for 17days. Also DJ oral feeding was conducted for 28days. The result of this study were as follows: Food intake and body weight gain in heavy metal administered groups were lower than those of NCG. Liver, kidney and testis weights were not significantly different among 5 groups. GOT, GPT and BUN activities were significantly reduced in DJ treated groups as compared to HMC. DJ showed the suppressing effect on the accumulation of Hg, Pb and Cd in serum, liver and kidney. Fecal Hg and Cd excretions increased with DJ feeding. The results suggested that DJ may have some protective effects on Hg, Cd and Pb intoxication by reducing the accumulation m tissues and increasing excretion. This study also showed the effective way of using duck-extract and its application to the oriental medicine.