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.

고관절 반 치환술의 대퇴 골절 예방을 위한 강선 고정의 효과

유정한 ( Jeong Han Yoo ),박용욱 ( Yong Wook Park ),박진수 ( Jin Soo Park ),노규철 ( Kyu Cheol Rowe ),정국진 ( Kuk Jin Chung ),김홍균 ( Hong Kyun Kim ),김형년 ( Hyong Nyun Kim ),임희준 ( Hee Joon Lim ),이철 ( Cheol Lee ),황지효 ( 대한고관절학회 2009 Hip and Pelvis Vol.21 No.2

목적: 무시멘트형 양극성 반 인공 관절 치환술에 있어서 수술 도중 발생하는 대퇴 골절 예방을 위한 예방적 강선 고정술의 효과를 분석하고자 한다. 대상 및 방법: 2004년 1월부터 2008년 8월까지 무시멘트형 양극 인공 관절 치환술을 받은 65세 이상의 환자 48명(1군)을 대상으로 하여 강선을 사용하지 않은 48명의 환자(2군)와 비교하였다. 평균 나이는 75.4세(1), 73.6세(2)이었고 평균 추시 기간은 19.1개월(1), 18.3개월(2)이었다. 수술 도중 골절 발생율 외에 수술 시간, 수술 도중 예상 출혈량, 입원 기간, 방사선학적 안정성을 측정하였고 임상적 평가를 위한 대퇴 통증과 Jensen의 기능 점수와 Parker와 Palmer의 활동 점수를 비교하였다. 결과: 1군에서는 수술 도중 골절이 발생하지 않았으며 2군에서 4예(8.3%)가 발생하였다(p=0.041). 수술 시간은 각각 172분(1), 162분(2) 예상 출혈량은 866 cc(1), 855 cc(2), 입원기간 36일(1), 35일(2)이었다. 방사선학적으로 침강은 1.59 mm(1), 1.67 mm(2)이었으며 임상적으로 대퇴 통증이 1예(1), 2예(2) 관찰되었다. 임상적으로 Jensen의 기능 점수는 평균 2점(1) 2.2점(2), Parke와 Palmer의 활동 점수는 평균 5.2점(1), 5.3점 (2)이었다. 결론: 무시멘트형 인공 관절 치환술에 있어서 예방적 강선 고정술은 골절률을 의의있게 감소시켰다. Purpose: The purpose of this study was to assess the effect of a prophylactic cable fixation for prevention of femoral fractures in cementless bipolar hemiarthoplasties. Materials and Methods: Forty-eight cementless bipolar hemiarthroplasties with prophylactic cable fixations on the femur were performed in patients>65 years of age between January 2004 and August 2008 (group 1). The control group which did not undergo prophylactic cable fixation included 48 cases (group 2). The mean age was 75.4 years (group 1) and 73.6 years (group 2). The patients were followed up for an average of 19.1 (group 1) and 18.3 months (group 2). The intra-operative fracture rates were compared. Additionally, operative time, estimated blood loss (EBL), and length of hospital stay were compared. Radiologic assessment for stem stability was performed. Clinical assessment was evaluated by the thigh pain and Jensen`s functional score, and Parker & Palmer`s mobility score. Results: There was no fractures in the cabled group (1), and 4 fractures (8.3%) in the control group (2; p=0.041). The mean operative time was 172 minutes (1) and 162 minutes (2), the EBL was 866 cc (1) and 855 cc (2), and the duration of admission was 36 (1) and 35 days (2), respectively. Radiologically, subsidence was 1.59 mm (1) and 1.67 mm (2). Clinically, one (1) and two (2) thigh pains were recorded and the functional score of Jensen was 2 (1) and 2.2 points (2), and the mobility score of Parker and Palmer was 5.2 (1) and 5.3 points (2), respectively. Conclusion: Prophylactic cable fixation is effective for reducing intra-operative femoral fractures.

간세포암의 고주파 열치료 후 천자침 경로를 통한 전이 1례

조영완,박석주,진한영,김준영,이재익,강명주,박정하,윤정희,박성재,지삼룡,이연재,이상혁,설상영 인제대학교 2006 仁濟醫學 Vol.27 No.-

Radiofrequency ablation(RFA), as a form of minimally invasive therapy for hepatocellular carcinoma, has become an important treatment modality. Because of limitation of surgery, RFA has become standard therapy for hepatocellular carcinoma in some situations. But there are some complications of RFA such as bleeding, infection, hematoma, adjacent organ thermal damage including intestinal perforation, needle track seeding, and so on. There are few reports in the literature that systematically evaluate the incidence of needle tract seeding and its associated risk factors. And only 2 cases of needle tract seeding of hepatocellular carcinoma after RFA were reported in Korea. We report a case of needle tract seeding of hepatocellular carcinoma after RFA.

개에서 이중 결찰법을 통한 동맥관 개존증의 완치 예

윤헌영,정순욱,박희명,박철,정만복,김준영,한현정,황민,노병국,박상혁,장하영,박정윤 한국임상수의학회 2004 한국임상수의학회지 Vol.21 No.1

A ten months old, female Yorkshire terrier weighing 2.88 kg referred to veterinary teaching hospital of college of veterinary medicine, Konkuk University because of syncope, cough and dyspnea. First hematological and serum chemical test revealed thrombocytopenia, mild anemia, and increase of concentration of ALP (195 U/L). On 57 days later, second hematological and serum chemical test revealed polycythemia, increase of concentration of ALP (211 U/L), and Tchol (387 mg/dl). Right atrium enlargement, main pulmonary artery bulge and cardiomegaly (VHS = 11.5) were observed in radiographic findings. Ultrasonographic images showed both right and left ventricular dilation and turbulent flow between the descending aorta and the main pulmonary artery in color Doppler imaging. ECG showed left ventricular enlargement, SA block, and electrical alternant. Thoracotomy was performed through left fourth intercostal incision under isoflurane anesthesia. Patent ductus arteriosus was double ligated with 1-0 silk. Cough and dyspnea disappeared on 5 days after operation. Turbulent flow was not found in color doppler imaging of ultrasonography on 10 days after operation. Ten months later after the operation, syncope could not exist any more.

Effect of a Series Connection of a Bi-Electrolyte Hydrogen Sensor in a Leak Detector

( Hyeuk Jin Han ),( Chong Ook Park ),( Young Kyu Hong ),( Jong Suk Kim ),( Jeong Woo Yang ),( Yoon Seo Kim ) 한국센서학회 2015 센서학회지 Vol.24 No.1

Conventional leak detectors are widely based on helium gas sensors. However, the usage of hydrogen sensors in leak detectors has increased because of the high prices of helium leak detectors and the dearth in the supply of helium gas. In this study, a hydrogen leak detector was developed using solid-state hydrogen sensors. The hydrogen sensors are based on Park.Rapp probes with heterojunctions made by oxygen-ion conducting Yttria-stabilized zirconia and proton-conducting In-doped CaZrO3. The hydrogen sensors were used for determining the potential difference between air and air balanced 5 ppm of H2. Even though the Park.Rapp probe shows an excellent selectivity for hydrogen, the sensitivity of the sensor was low because of the low concentration of hydrogen, and the oxygen on the surface of the sensor. In order to increase the sensitivity of the sensor, the sensors were connected in series by Pt wires to increase the potential difference. The sensors were tested at temperatures ranging from 500.600oC.

대동맥 협착증과 동반된 출혈성 위장관 동정맥 기형에서 Estrogen-Progesterone 치료 1예

김도연,김화정,김효정,남준식,박수영,박영미,신정은,주미순,황민규,정혜경,손혜영,이선영,이한주 大韓消化器內視鏡學會 1999 Clinical Endoscopy Vol.19 No.부록2

경주지역 여고생의 초경과 체성장간의 관계

김준섭,권오구,박진석,오종수,박정현,박제식,안세한,이용환,서정호,신태섭,최영배,김덕수,이관,박수경 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

본 연구는 경주지역 1개 고등학교 3학년 여고생을 대상으로 초경 시작 전인 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레 수치와 초경 연령을 파악하여 여성의 초경이 빠를수록 체성장 속도의 변화가 있을 것이라는 가설을 기초로 두 요인간의 관련성을 파악하고자 시행되었다. 경주시 1개 여자고등학교 3학년생 총 317명에 대해 ㅊ경 나이, 초경시 심리 상태, 초경이 시작되었을 때의 상담 여부와 상담하였던 사람, 부모 신장과 초경전후의 식사 규칙성, 다이어트 경험, 수면시간, 스트레스, 음주/흡연 여부, 질병력 등에 대한 설문 조사를 시행하였고, 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레에 대한 정보는 건강기록부에서 확보하였다. 상기 대상자 중 건강기록부가 분실된 39명, 초경나이에 대해 응답하지 않았던 29명 및 결석 등으로 조사를 하지 못하였던 42명을 제외한 조사 대상자는 206명으로 선정하였다. 대상자들의 초경연령 평균값(Mean±SD)은 13.0±1.11이었고, 초등학교 4학년부터 고등학교 2학년까지의 초경 이후 신장 성장률은 감소하였으며, 초경연령이 빠른 군이 초등학교 때는 신장에 있어서 우위를 차지하나 고등학교에 오면서 신장은 비슷한 수준이 되었다. 초경후 1-2년 사이에 체중과 흉위의 증가율은 감소하였고, 초경연령이 빠른 군이 초등학교와 고등학교 사이에 체중과 흉위에서 모두 우위를 차지하였다. 본 연구의 결과는, 흔히 이차 성징의 시작 시점 혹은 사춘기의 시작 시점으로 보고있는 초경 연령이 청소년기의 성장과 밀접한 관련성이 있고, 특히 체중과 흉위의 성장 속도와 밀접한 관련성이 있음을 시사한다. To understand the onset of menarche in relation to changes in physical growth that take place during female adolescence, especially the changes in height and weight velocity. The 207 senior in one women high school of Kyongju were investigated in April 3 to 8, 2001. We collected the information, relation in the age at menarche, height & weight of parents, regularity of eating, and obesity diet, duration of sleeping, sickness & stress near age at menarche, by self-recording. The status of height, weight & chest circumference between the 4th grade of primary school and the junior of high school was collected by individual Health Record. The results were followed; The average age at menarche was 12.95±1.11 years old and the most frequent age of menarche is 13 years. After menarche, the velocity of height, weight and chest circumference were decreased. The most rapid group of menarche hold dominant position in height during elementary school. As time passed, they dont hold dominant position in height. The most rapid group of menarche get an advantage in the weight and the girth of chest after elementary school. The height of subjects is directly proportional to the height of their parents. These results suggest that the starting age at menestuation can be closely associated with physical growth and development.