타이타늄 임플란트와 상부구조물의 갈바닉 쌍의 전기화학적 특성

오근택,김명화,최병갑,김경남 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.1

For the aesthetic and functional restoration of edentulous patients, recently dental implants have been used widely. Dental implants and restorative alloys are required with the high corrosion resistance. Suprastructure and implant with different compositions, which are in electrical contact, may develop galvanic or coupled corrosion problems. Besides galvanic corrosion, crevice and pitting corrosion may occur in the marginal gap or the gap between dental implant assemblies. In this study, Ti implants, gold, silver-palladium, cobalt-chromium and nickel-chromium suprastructures were used to investigate their galvanic and crevice corrosion of suprastructure/Ti implant couples. Potentiodynamic and potentiostaic testing were performed in artificial saliva at 37℃. Potentiodynamic testing was carried out at the potential scan rate of 1 ㎷/sec and in the range of -600∼1600 ㎷(SCE). Potentiostatic testing such as open circuit potential and current densities at -250, 0 and 250 ㎷(SCE) was performed for 5000 seconds in artificial saliva. After electrochemical testing, the surface and cross-sectional morphologies of the samples were observed using optical microscopy. Potentiodynamic test results indicated that suprastructure/Tim implant couples exhibited the passive current density range of 0.5∼12 ㎂/㎠, Ti abutment/Tim implant and gold/Tim implant couples exhibited relatively low passive current density, Co-Cr/Tim implant couples the highest. Co-Cr and Ni-Cr/Tim implant couples showed the breakdown potentials of 700 and 570 ㎷(SCE), respectively. Open circuit potentials of silver, Ti abutment, gold, Ni-Cr and Co-Cr/Ti implant couples were -93.2±93.9, -123.7±58.8, -140.0±80.6, -223.5±35.1, and -312.7±29.8, respectively and stable according to immersion time. The couples exhibited cathodic current densities at -250 ㎷(SCE), especially, gold and silver alloys showed the high cathodic current densities of ±3.18 and ±6.63 ㎂/㎠, respectively. At 250 ㎷(SCE), Ti abutment/Ti implant couples exhibited the lowest current density of 9.48×10^-2 ㎂/㎠, and gold, Ni-Cr, Co-Cr and silver/Ti implant couples exhibited 0.313, 1.27, 5.60 and 8.06 ㎂/㎠, respectively. The couples exhibited relatively low current densities at 0 ㎷(SCE). The photographs after electrochemical testing showed crevice or pitting corrosion in the marginal gap and suprastructure surface. Although Co-Cr/Ti implant couples among the tested samples had the possibility of the galvanic corrosion, its degree was not significant.

초음파가공에 의한 박판 버 제거기술

정연택,신용주,김병희 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

The shearing process for the sheet metal is normally used in the precision elements such as a frame of TFT-LCD or lead frame of IC chips. In these precision elements, the burr formation prevents the system assembly and needs the additional burr removing process. In this study, we have developed the novel ultrasonic deburring system to remove the small burr came from shearing of the sheet metal effectively. The deburring tool is driven by the stepping motor and alumina and SiC particles are used as abrasives. Ultrasonic power and the flowing resistance of the abrasives make ti possible to abrasive the burr.

읽기폭 검사의 신뢰도 연구

이병택 서울大學校 社會科學大學 心理科學硏究所 2002 心理科學 Vol.11 No.1

읽기폭 검사는 언어이해처리에 필요한 작업기억의 용량을 측정한다고 알려진 과제이다. 이 검사는 근래의 언어이해와 관련된 개인차 연구에서 많이 사용되어 부분적으로 타당도를 인정받은 검사이다. 그러나 아직까지 이 검사의 신뢰도는 보고된 바가 없다. 따라서 본 연구에서는 읽기폭 검사의 신뢰도를 검토하고자 하였다. 신뢰도의 검토를 위해 검사-재검사 신뢰도와 동형검사 신뢰도 방법을 이용하여 읽기폭 검사의 신뢰도를 측정하였다. 특히 동형검사 신뢰도를 측정하기 위해서 읽기폭 검사 한 벌을 추가로 고안하였다. 두 가지 유형의 신뢰도에서 읽기폭 검사는 비교적 높은 신뢰도를 보여주었다. The reading span test is the one that measures working memory capacity required in reading comprehension. In several individual difference studies on language comprehension, this task has proved to be valid. However, there has been no report on the reliability of the task. The goal of this study is to measure the reliability of the reading span test. To do this, the test-retest reliability and the alternative test reliability of the test have been measured. Especially, to measure the alternative test reliability, the alternative test of the reading span test was made. The reading span test shows relative high reliability in two indices.

세포질내 정자주입법(ICSI)에 있어서 정자흡입 및 난자내 주입방법에 관한 연구

이택후,김항진,송건호,김대근,전상식,박윤규,서태광,전병균,류은경,이은숙,문진수,김광철 경북대학교 의학연구소 2000 경북대학교병원의학연구소논문집 Vol.4 No.1

Study on Method of Sperm Aspiration and Injection into an Oocyte in Intracytoplasmic Sperm Injection(ICSI) Immobilization of spermatozoa prior to intracytoplasmic sperm iniection(ICSI) sometimes results in crooked tail and this makes it difficult to aspirate sperm into an injection pipette tail first. Head-first sperm aspiration into an injection pipette avoid this problem due to the bigger size of the sperm head. The effect of head or tail-first sperm injection into an oocyte on fertilization cleavage, percentage of grade I embryos and development to blastocyst stage in ICSI program has been studied. A single living immobilized spermatozoa from oligoasthenozoospermic patient was injected into an oocyte head-first or tail-first according to the treatment. Eighteen hours after microinjection, oocytes ware inspected for survival and fertilization Fertilized oocytes with two pronuclei were cultured in 30μl drop of mHTF supplemented with 10% heat-inactivated follicular fluid(FF) at 37℃. On day 2. embryo transfer was performed with cleaved embryos. The remaining 2-8 cell stage embryos were co-cultured with BRL cells in mHTF + 10% FF for 72 hours and the developmental stage was observed. The data were analyzed by Analysis of Variance. A total of 164 oocytes from 36 cycles were assigned to earth treatment and ICSI was performed(88 head-first, tail-first). The rates of normal fertilization were 81.8% and 76.3% for head-first and tail-first, respectively. Of the fertilized oocytes, the percentage of cleaved embryos and the percentage of grade 1 embryo among cleaved embryos were 88.9% and 68.8%, 93.1% and 74.1% for head-first and tail-first, respectively. Of the 2-8 cell embryos cultured, 44.4%(16/36) and 50.0%(10/20) for head first and tail first, respectively developed to blastocyst stage. There were no differences in fertilization, cleavage, rates of grade 1 embryos, and development to blastocyst stage. In conclusion, head-first or tail-first sperm injection into an oocyte in ICSI program does not affect fertilization and subsequent embryo development to blastocyst stage in vitro.

복숭아나무 揷穗의 크기와 저장양분의 發根과 圃場活着에 미치는 影響

林敬鎬,金炳三,黃仁澤,金月洙,金光秀,金相喆 全南大學校 農業科學技術硏究所 1998 農業科學技術硏究 Vol.33 No.-

복숭아나무 경지삽목 번식에 있어서 삽수 굵기와 길이 및 삽수내 저장 양분 함량이 발근과 포장활착에 미치는 영향을 구명하였다. 삽수 굵기는 直徑 5∼8㎜의 삽수가 발근율이나 발근수, 발근장 등 뿌리 발달이 좋았으나 포장 활착율은 삽수재 저장양분이 많은 직경 8∼11㎜가 좋았다. 삽수 길이는 20∼30㎝ 처리가 발근율, 발근수, 발근장 등 발근력이 좋았으나 포장 활착율은 삽수재 잔존 저장 양분이 많은 30㎝ 길이가 좋았다. 삽목용 적정삽수는 8㎜ 굵기에 30㎝ 길이가 가장 효과적이었으며 포장에서 활착후 묘고, 간경 등 생육은 모든 처리에서 116㎝ 이상, 20.4㎜ 이상으로 삽목 당년에 우량묘가 생산되었다. This experiment was studied to examine the effect of cutting size and storage nutrient on rooting and survival in field using hardwood cutting of 'Sunaga Wase' peach to establish mass production system of rooted cutting. Cuttings having 5 to 8㎜ in stem diameter showed the best rooting percentage, root number and root length. In the survival in field, the stem diameter of 8 to 11㎜ showed the highest survival rate and less consumption of storage nutrient during cutting. Those hardwood cuttings of 20 to 30㎝ in stem length showed the best rooting, and higher survival in field was obtained in 30㎝ long cuttings. After transplanting rooted cuttings to field, tree height and trunk diameter of 'Sunaga Wase' peach was 116㎝ and 20.4㎜, respectively.

Design of Low Phase-Noise Oscillator Based on a Hairpin-Shaped Resonator Using Composite Right/Left-Handed Transmission Line

Byeong-Taek Moon,Noh-Hoon Myung THE INSTITUTE OF ELECTRICAL ENGINEERS 2014 IEEE Microwave and Wireless Components Letters Vol. No.

<P>In this letter, a low phase-noise microwave oscillator based on a hairpin-shaped resonator (HSR) using a composite right/left-handed transmission line (CRLH TL) is proposed. The proposed HSR consists of the conventional transmission line (CTL) and the CRLH TL. In order to obtain the high- Q factor, an electric field is concentrated on the CRLH TL, and then the CRLH TL provides a low loss due to a slow wave effect. The proposed HSR has a very compact size of 0.105 λ<SUB>g</SUB> ×0.19 λ<SUB>g</SUB>. An oscillator based on the HSR was designed, fabricated and measured. At the oscillation frequency of 4.95 GHz, the measured phase noise is -120.5 dBc/Hz at 100 kHz offset with 4.93 dBm output power.</P>

CRLH 전송선을 이용한 Marchand 발룬의 소형 격리 회로 설계

문병택(Byeong-Taek Moon),한정훈(Jung-Hoon Han),명로훈(Noh-Hoon Myung) 한국전자파학회 2012 한국전자파학회논문지 Vol.23 No.9

Marchand 발룬의 평형 단자들의 임피던스 정합과 향상된 격리도 특성을 위한 소형 격리 회로를 설계하였다. 제안한 소형 격리 회로는 Composite Right/Left-Handed(CRLH) 전송선과 CRLH 전송선의 단위 셀을 이용한 소형위상 반전기로 각각 구성된다. 또한, 이 소형 격리 회로에 대한 설계 방법을 제시하고 분석하였다. 기본적인 격리 회로의 크기인 0.5 λg에 비해서 CRLH 전송선을 이용한 경우는 0.11 λg로 소형 위상 반전기를 이용한 경우는 0.07 λg 로 각각 소형화 시켰다. 제안된 소형 격리 회로를 이용한 Marchand 발룬의 동작 주파수는 2.45 ㎓이고, 실험을 통하여 검증하였다. In order to obtain balanced ports matching and isolation between balanced ports of a Marchand balun, a compact isolation network is proposed. The proposed compact isolation network is designed using composite right/left-hand (CRLH) transmission line and compact phase inverter using CRLH transmission line unit cell. Also, design method and analysis of proposed isolation network are presented. The sizes of the proposed isolation networks are significantly reduced to 0.11 λg and 0.07 λg compared with the conventional isolation network of 0.5 λg. The Marchand balun is operated at 2.45 ㎓ and is demonstrated through excellent experimental results.

각막 점액종 1 예

이병택(Byeong Taek Lee),이종혁(Jong Hyunk Lee),조미연(Mi Yeon Cho),김순현(Soon Hyun Kim) 대한안과학회 1994 대한안과학회지 Vol.35 No.2

감압밸브 성능에 영향을 미치는 요인들에 관한 고찰

윤병택(Byeong-Taek Yun) 대한설비공학회 2019 대한설비공학회 학술발표대회논문집 Vol.2019 No.-

A pressure reducing valve is used as a device for maintaining an appropriate pressure on the user side. There are many factors that affect the pressure reducing valve performance. Factors include system water pressure, cavitation, water impact, and dissolved air, etc. In this paper, we investigate the problems that may be caused by the factors mentioned above and suggest ways to solve them.

억제와 재인 읽기폭 검사

이병택(Byeong-taek Lee),이경민(Kyoung-Min Lee),김정오(Jung-Oh Kim),홍재성(Chai-Song Hong) 한국인지과학회 2002 인지과학 Vol.13 No.4