Effect of Impact Velocity on Interface Characteristics of HT‑9 Steel Joints Fabricated by Magnetic Pulse Welding

Jun‑Woo Song,Jin‑Ju Park,Gyoung‑Ja Lee,Min‑Ku Lee,Kyu‑Hyun Park,Soon‑Jik Hong,Jung Gu Lee 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.3

The weldability window in magnetic pulse welding (MPW) is proposed for the end-closure joining of HT-9 steel tubularworkpieces. Based on both theoretical and experimental investigations, the impact velocity of the flyer tube at the momentof collision had a dominant effect on the bonding characteristics of the resultant joints and the optimal impact velocity wasestimated to be in the range of 265–290 m/s in this alloy system. Under the optimal process conditions, no leak was detectedduring helium leak testing. Moreover, the integrity of the joint interface was preserved until the tube section ruptured duringinternal pressure burst testing. For HT-9 steel, the ductile δ-ferrite phase produced by the localized interfacial melting duringMPW acted as an effective obstacle to crack propagation, thereby enhancing the fracture resistance of the joint interface. Allof the results demonstrated the high integrity and durability of the HT-9 steel tube assembly fabricated by the MPW process.

연령증가에 따른 혈압요소들의 좌심실비대 및 관동맥질환과의 관련성

박재석,박창규,박미영,박재형,김용현,나진오,신성희,서순용,홍순준,박성미,임홍의,김응주,서홍석,오동주,노영무 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.2

서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1998)

김재홍,김준호,반재용,이정우,황성주,정준규,정성태,강진문,조흔정,홍창의,정혜신,이한승,김이선,이봉길,이종호,선영우,한기덕,윤성필,이성훈,안종성,박석범,문승현,조항래,김형섭,류지호,황재영,박준홍,손상욱 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1

In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria gonorrhoeae(PPNG), we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by menas of the chromogenic cephalosporin method. In 1998, 93 strians of N. genorrhoeae were isolated, among which 60(64.5%) were PPNG. The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 64.5% in 1998.

Clinical usefulness of infrared thermal imaging as a non-invasive screening test for diagnosis of vascular malformations

( Chihyeon Sohng ),( Jun Hong Park ),( Won Kee Lee ),( Jun Young Kim ),( Yong Hyun Jang ),( Weon Ju Lee ),( Seok-jong Lee ) 대한피부과학회 2018 대한피부과학회 학술발표대회집 Vol.70 No.2

Background: Infrared thermal imaging (ITI), aka thermography, has been used widely in medicine, but been studied rarely its clinical application in vascular malformations (VMs). Objectives: This study investigated validity and usefulness of ITI as a new screening test to differentiate between capillary malformation (CM) and arteriovenous malformation (AVM). Methods: This study included 50 patients with VMs who conducted ITI between 2011 and 2018. They were divided into two groups; CM and AVM, and those with Parkes-Weber syndrome (PWS) were also included in AVM group. Temperature difference (ΔT) between lesional and contralateral non-lesional area was compared using ITI to calculate the maximum ΔT (ΔTmax). The receiver operating characteristic (ROC) curve was then plotted to determine optimal cutoff value of ΔTmax. Results: Of the total 50 patients, 34 were finally diagnosed with CM, and 16 AVM (12 pure AVM, and 4 PWS). AVM group had significantly higher ΔTmax (2.57±1.23°C) than CM group (0.69±0.50°C).The area under the curve of ΔTmax for diagnosis of AVM versus CM was 0.938. The sensitivity and specificity were showed 87.5% and 94.1% (LR+, 14.87; LR-, 0.13) in cutoff value of ΔTmax 1.39°C, and 81.3% and 97.1% (LR+, 27.62; LR-, 0.19) in cutoff value of ΔTmax 1.42°C. Conclusion: The value of ΔTmax measured by ITI was useful to distinguish AVM from CM, so ITI can be employed as a new non-invasive differential screening test for uncertain VMs.

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

고속주축 모니터링용 광파이버 변위센서의 레이저 다이오드 출력에 따른 성능평가

박찬규,신우철,홍준희,이동주 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

This paper is to develop an optical fiber displacement sensor for monitoring high speed spindle. Proper magnitude of optical power as well as amplification of output signal are necessary to improve sensitivity of the sensor. In this paper, to meet the need of improvement of the sensor resolution, we choose proper optical power and amplification level through speculating on optical power of a laser diode.

탱자(Poncirus tripoliata RAF)잎으로부터 Mitochondrial DNA의 분리

박종필,전홍성,김연순,이숙영,김성준 조선대학교 부설 유전생물공학연구소 1992 유전생물공학연구지 Vol.2 No.-

Differaitial centrifugation, sucrose(30%, 60%) and percoll(13.5%, 21% and 45%) density gradient centrifugation were used to effectively isolate mitochondria and mitochondrial DNA (mt DNA) from the leaves of the genus Poncirus (Pondrus trifoliata RAF.) The results showed that percoll density gradient centrifugation provided a convinient and effective method for the preparation of clean mitochondria. The purity of prepared mt DNA was increased by the removal of the nuclear DNA by DNase treatment to the crude mitochondrial suspension mt DNA on the agarose gel was shown extra fluorescent background in case of isolation by differential centrifugation and more cleared band included slightly smeared patterns for sucrose density gradient, and highly paint band from percoll density gradient was appeared to the best results of the above three methods. In addition to chromosomal mt DNAs, two short mt plasmid-like elements were detected in the genus Poncirus. These elements consistently co-purified with the chromosomal mt DNAs and is widely distributed among natrual Poncirus trifoliata RAF. populations. But these elements required proteinase K treatment for mobility in agarose gels.

접촉연소검지방식을 이용한 후막형 메탄가스센서의 제조 및 그 특성

박준식,이재석,홍성제,박효덕,신상모 경북대학교 센서기술연구소 1995 센서技術學術大會論文集 Vol.6 No.1

본 연구에서는 스크린 프린팅 기술을 이용한 병렬저항열원을 갖는 후막형 가연성 가스센서를 제조하고, 메탄가스에 대한 감도특성을 조사하였다 알루미나 기판의 양면 위에 제조된 병렬형 백금 후막발열체는 후막형 백금 저항체로 사용된 백금페이스트 온도 감지 특성과 표면 특성을 조사하여 paste A로 선정하였다. 제조된 백금 후막 발열체는 평균저항값이 1.8Ω이고, TCR값은 3685ppm/℃이었다. 제조된 백금 발열체상에 Pt과 Pd이 첨가된 촉매 페이스트를 제조하고 가지부는 Pt과 Pd가 첨가된 촉매를 스크린 프린팅하여 후막을 형성하고 열처리하여 제조하였다. 제조된 후막형 센서는 메탄가스에 대해 4.3mV/1009ppm의 감도를 보였으며, 소비전력은 2.12W이었다. We fabricated the sensors with parallel Pt heaters using screen printing process and investigated sensitivities to hydrocarbon gases. The paste A was selected as Pt paste for heater by investigated the properties of TCRs and thick film microstructures. The average resistance of parallel Pt heaters was 1.8Ω, and the best TCR obtained was 3685ppm/℃. On the top of the Pt heaters, a sensing layer added with Pt and Pd as catalyst paste was screen printed and heat treated. The sensitivity of fabricated the sensor was 4.3mV/1000ppm to methane. The power consumption of the sensors was 2.12watts

고속 주축 상태 모니터링용 광파이버 변위 센서 설계 제작 및 성능평가

홍준희,박찬규,신우철,이동주 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

This paper is focused on practical applicability of the optical fiber sensor considering the machine center which is going to use them. Optical fibers may be fluctuated because the machine center operates as column moving type. This causes distortion of the sensor output signal. To reduce this problem, we have improved the sensor structure and its bracket. And we evaluated performances of the sensor.

고속주축 모니터링용 광파이버 변위센서의 파이버 특성에 따른 센서 성능 연구

박찬규,신우철,배완성,홍준희,이동주 한국공작기계학회 2003 한국공작기계학회 추계학술대회논문집 Vol.2003 No.-

To make high speed spindle system work properly, sensors with outstanding resolution and dynamic characteristics are essential. An optical fiber displacement sensor is based on simple principles. Electrical signal responds to the optical flux change due to the displacement change between a target and a sensor probe. In this paper, the performance of optical fiber displacement sensor has been investigated according to properties of optical fiber. Firstly, optical loss has been measured before and after polishing optical fiber endface. Secondly, allowance of optical fiber bending has been tested. thirdly sensitivity and linear range of the sensor has been found out according to the shape of cross section of optical fiber.