온도변화에 따른 알루미늄합금 용접부의 피로수명에 관한 연구

이동길,양승훈,김건호,정재강 朝鮮大學校 機械技術硏究所 2002 機械技術硏究 Vol.5 No.1

본 연구에서는 저온용기 등에 많이 사용되고 있는 알루미늄 합금 A15083-0재에 대한 보호가스 혼합비율과 피로수명과의 관계를 규명하고자 혼합가스 비율을 여러 가지로 달리하여 GMA 용접을 실시하였다. 시험온도는 상온에서 극저온까지 단계적으로 낮추어가며 실시하였다. 용접재의 피로수명은 모든 불활성가스 혼합비율 및 노치 가공위치에서 모재보다 높은 피로수명을 보였으며, 영향부, 용융선 및 용착금속부 순으로 피로수명이 증가하였다. 상온에서부터 -85℃까지는 온도가 낮아짐에 따라 피로수명은 모재 및 Ar33%+He67%의 경우 증가한 반면, 다른 불황성 가스혼합비에서는 감소하는 경향을 나타내었며, -196℃ 극저온에서는 피로수명 크게 증가하여 저온재료로서 유용한 성질이 나타났다. The influence of mixing shield gas ratio and test temperature on fatigue life of welding zone were examined experimentally for a AI5083-O aluminum alloy. The GMA(Gas Metal Arc) welding was carried out for weld specimen with various mixing gas ratio(Ar100% + He0%, Ar67%+He33%, Ar50%+He50%, and Ar33%+He67%). The tested temperature range was from room temperature(+25℃) to cryogenic temperature(-192℃). The welding zone was divided into four sub-zones for analysis ; weld metal, fusion line, HAZ, and base metal. In the influence of mixing gas ration, fatigue life of weld metal was decreased with higher Argon gas ration, but fusion line and HAZ specimens were not influenced greatly, The fatigue life increased at lower temperatures, particularly at -196℃. It was known availability that the A15083-O is appropriate for used low temperature material.

STR 유전자의 개인식별력 측정을 위한 통계량

이혜승,이재원,한길로,황적준 大韓法醫學會 1998 대한법의학회지 Vol.22 No.2

When we intend to do the personal identification using DNA profiles, it will obviously be better to use as much information as possible. The power of identification is increased by using the genetic marker system such as VNTRs or STRs. Although STRs do not have many alleles per locus as VNTRs, these can be compensated by a large number of loci that are potentially usable. However, it will be more efficient to use a morphic loci. Therefore, prior to choose the genetic marker system of STRs for identification, it is essential to consider the statistical parameters of each STR locus, such as obs-H(observed heterozygosity), exp-H(expected heterozygosity), pM(probability of match), DI(discrimination index), PD(power of discrimination), MEC(mean exclusion chance), MEP(mean exclusion paternity), PIC(polymorphic information content) et al. In this article, we described the exact meaning of statistical parameters for the purpose of identification.

장기 이식 환자에서 Voriconazole 과 Cyclosporine 또는 Tacrolimus의 상호작용

한혜원,김재연,송영천,김승은,유성길 한국병원약사회 2009 병원약사회지 Vol.26 No.1

Abstract: In organ transplant patients, the opportunity of fungi infections such as invasive aspergillosis increase by use of immunosuppresant drugs and voriconazole is recommended as primary treatment drug. When voriconazole is administered with cyclosporine(CsA) or tacrolimus(FK506), caution about increment of blood CsA or FK506 concentrations that caused by the change of CYP3A4 activity is required but few domestic cases of interaction were reported yet, The purpose of this study was to assess the effect of voriconazole on the blood CsA or FK506 concentrations in transplant recipients and the factors of recipients that have an effect on the results. 25 transplant recipients who were administered voriconazole with CsA or FK506 from January 1 of 2006 to August 17 of 2008 in Asan Medical Center were objects (12 patients on CsA coadministration arm - 9 males, 3 females; 41~62years;2 liver, 2 kidney, 3 bone marrow, 5 heart transplant recipients, and 13 on FK506 coadministration arm - 7 males, 6 females;26~65years; 10 liver, 2 kidney, 1 heart transplant recipients). Blood CsA or FK506 concentrations before and after coadministration of voriconazole, and maximum concentration in one month from the first day of coadministration were monitored retrospectively. In most cases CsA or FK506 were administered as recommended doses regardless of coadministration of voriconazole, and blood concentration increased from 239.42±126. 77ng/ml to maximum 411.92±225. 76ng/ml in CsA coadministration arm(p=0.003), and from 7.72±2.79ng/ml to maximum 19.16±9.35ng/ml in FK506 coadministration arm(p=0.003). Gender, age, and the kind of transplant organ did not affect to the change of blood concentration in both two arms. In consequences, administration of voriconazole could affect on the blood CsA or FK506 concentration, and in cases of administra tion of voriconazole in transplant recipients treated with CsA or FK506, close monitoring and dose adjustment is needed.

매실박, 당근박, 감귤박 급여가 산란계 난황의 Vitamin E, K 함량에 미치는 영향

최승현,나재천,권오상,박상미,이봉덕,안길환 충남대학교 농업과학연구소 2008 농업과학연구 Vol.35 No.2

This experiment is a quantitative experiment where insoluble Vitamins E and K are extracted from the yolk of the spawning which was fed by by-products of tangerine, carrot, or Japanese apricot. Finally the purpose is to raise contents of the insoluble Vitamins E and K inside the yolk of the spawning. The saponification method through α, α - dipyridyl was used to determine the content of Vitamin E. Diethyl dithiocarbamate assay was used to examine the content of Vitamin K. The contents of Vitamin E in egg yolks of chicken fed by by-products of tangerine, carrot, or Japanese apricot increased 2 - 3 times compared to control egg, while the contents of Vitamin K almost no changed. 본 실험에서는 감귤, 매실, 당근의 껍데기로 감귤박, 매실박, 당근박을 먹여 산란계의 난황에 들어있는 Vitamin E와 K 함량을 높이고자 했다. Vitamin E 추출방법에는 검화방법인 α, α -dipyridyl에 의한 비색정량법을 사용하였으며 전처리 과정 중 석유 ether를 가하여 층을 분리하는 과정과 증류수를 가하여 층을 분리하는 과정에 있어서 신중을 가하였고 신속한 시료 전처리과정이 요구되었다. Vitamin K 추출에는 Diethyl dithiocarbamate에 의한 방법이 사용되었다. 실험결과 일반난황에서의 Vitamin E 함량보다 실험난황에서의 Vitamin E 함량이 2배 이상 높아졌음을 알 수 있었던 반면 Vitamin K의 함량은소량 증가하여 큰 변화가 없었다. 위의 결과를 통해서 난황에 이전된 Vitamin E의 종류가 무엇이며 어떠한 형태의 Vitamin E가 이전이 많이 되었는지를 확인하는 실험이 필요할 것이다. 이러한 추가적인 실험이 이루어졌을 때 상업적으로 이용한 가치가 있는 가를 고려하여야 할 것이다.

散亂線 除去用 格子 特性에 關한 檢討

한재진,이성길,김승국,김영근 광주보건대학 1992 論文集 Vol.17 No.-

For the researches physical characterisitcal of stationary Grid, how to use of fluorescence meter and conventional in clinic for the film method made an experimental study on the image quality influenced scattered radiation and abtained the results as follows. 1. Direct transmitted radiation is decrease for the Grid-ratio to increase and variable X-ray tube voltage thichness of phantom is not variation. 2. Scattered radiation content is better for increase on thickness of phantom. But using increase of X-ray tube voltage. 3. At the Acry1 phantom 15∼20 ㎝ equivalent to A-P and lateral projectin for the skull phantom using the 8 : 1 Grid showed image quality.

접촉각 측정을 통한 Alkanethiol로 표면 처리한 은 분말의 표면 특성 연구

이길재,신승일,오성근 한국공업화학회 2004 공업화학 Vol.15 No.1

은 분말을 alkanethiol로 표면 처리한 후, alkanethiol의 탄소 개수 변화에 따른 은 입자의 표면 특성변화를 접촉각 측정을 통해 연구하였다. 이때 은 입자 표면에 alkanethiol의 흡착여부를 DRIFT (diffuse reflectance infrared fourier transform) spectrum를 통해 확인하였다. 접촉각은 Washburn 식을 바탕으로 한 liquid penetration 방법으로 측정하였고, 이 측정법의 보완을 위해 분말에 압력을 가하여 원판형태로 만들어 그 표면에서 접촉각을 측정하는 sessile drop 방법을 함께 사용하였다. 그 결과 순수한 은 입자의 물에 대한 접촉각은 두 가지 방법에 대해 각각 58°, 40° 나왔고, 다양한 탄소개수(C_(4)-C_(12))의 alkanethiol로 표면 처리한 입자는 모두 90° 이상의 결과를 얻었다. 즉 alkanethiol로 처리한 은 입자의 표면이 소수성으로 변했음을 의미한다. 여기서 처리한 alkanethiol의 탄소개수가 증가할수록 접촉각은 계속 증가했으나, 접촉각의 증가 폭은 상대적으로 점차 감소하였다. Contact angles of silver powders were measured for investigation of surface properties of silver particles as changing alkyl chain length of alkanethiol. Silver powders were modified by various alkanethiol (C4∼C12). Adsorption of alkanethiol on silver particles was confirmed by DRIFT (diffuse reflectance infrared fourier transform) spectrum. Contact angles were measured by liquid penetration method based on Washbum equation and sessile drop method on tablet of compressed powder. In result. the value of contact angles on water were 53°, 40°about two method. Contact angles of surface treated particles by alkanethiol of varied alkyl chain length were larger than 90°. Because of bonding between silver and sulfur in alkanethiol, silver surface was surrounded by alkyl groups of alkanethiol. Surface properties of silver particles were increased on hydrophobicity with alkyl chain length of alkanethiol. In comparison with increase of contact angle accordingto increase of alkyl chain length of alkanethiol. the widths of increasing contact angle were relatively decreased.

Al5083-O 용접부의 보호가스 혼합비율에 따른 저온 인성 평가

이동길,이상열,양훈승,정재강 朝鮮大學校 機械技術硏究所 2002 機械技術硏究 Vol.5 No.1

본 연구에서는 저온용기 등에 많이 사용되고 있는 알루미늄 합금 A15083-O재에 대한 보호가스 혼합비율과 저온인성과의 관계를 규명하고자 혼합가스 비율을 여러 가지로 달리 하여 GMA 용접을 하였다. 시험온도는 상온에서 극저온까지 단계적으로 낮추어가며 계장화 샬피충격시험을 실시하였다. 최대하중은 시험온도가 낮아질수록 증가하였으나 변위는 25℃부터 -85℃까지는 시험온도에 관계가 없었으나 -196℃에서는 크게 감소하였으며, 모든 시험온도 및 불활성가스 혼합비율에서 흡수에너지는 용착금속부, 용융선 및 HAZ 순으로 증가하였다. 용착금속부의 흡수에너지는 시험온도 및 불활성가스 혼합비율에 관계없이 매우 낮게 나타난 반면, 용융선 및 HAZ시험편의 흡수에너지는 모재와 거의 유사한 값을 나타내었다. 또한, 모든 시험온도에서 흡수에너지는 He의 혼합량이 증가할수록 증가하는 경향을 보여 Ar33%+He67%에서 가장 우수한 인성을 나타내었다. In this study, the low temperature toughness was evaluated by using the instrumented Charpy impact testing procedures for A15083-O aluminum alloy used in the LNG carrying and storing tank. The specimens were GMA(Gas Metal Arc) welded with four different mixing shield gas ratios (Ar100% + He0%, Ar67%+He33%, Ar50%+He50%, and Ar33%+He67%), and tested at four different temperatures(+25, -30, -85, and -196℃) in order to investigate the influence of the mixing shielding gas ratio and the low temperature. The specimens were divided into base metal, weld metal, fusion line, and HAZ specimen according to the notch position. From experiment, the maximum load was increased a little up to -85℃, and the maximum load and maximum displacement were shown the highest and the lowest at -196℃ than the test temperatures because of the brittle behavior. The absorption energy of weld metal notched specimens was not nearly depends on test temperature and mixing shield gas ratio because the casting structure was formed in weld metal zone by melting welding wire. In the other hand, the others specimens was shown that the lower temperature, the higher absorption energy slightly up to -85℃ but the energy was decreased so much at -196℃.

모래다짐말뚝의 원심모델링

유남재,정길수,김상진,채승호 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

This paper is results of extensive centrifuge model experiments about design factors influencing the bearing capacity and the settlement behaviors of SCP (Sand Compaction Pile). Centrifuge model tests were carried out changing design factors for SCP method such as replacement area ratio (as= 20, 40, 70%), improvement ratio to footing width (W/B = 1, 2, 3), and amount of fines in sand pile (#200 = 5, 10, 15). Therefore, the effects of these design factors on the bearing capacity and the settlement behavior of SCP were investigated and changes of stress concentratio rato due to such an design factors were also investigated. Centrifuge model testing technique for preparing and installing centrifuge model of sand compaction pile, using freezing them, was also developed. As results of centrifuge model tests, more fines in sand compaction pile increases the bearing capacity of SCP. Optimum improvement ratio to footing width was found to be 2. Values of stress concentration ratio was in the ranges of 1.5 - 3.5. The depth of bulging in sand piles was found in the range of 2.0 - 2.5 times of pile diameter.

DNA 증거의 집단유전학적 분석을 위한 SAS시스템

이효정,이혜승,한길로,이재원,황적준 大韓法醫學會 2000 대한법의학회지 Vol.24 No.1

DNA analysis has become one of the most powerful tools in forensic inference for human identification and is now used worldwide. It is used to be statistical technique for the individual identification of a civil and criminal action. The purpose of this article is computerization of the statistical technique for the population study and DNA evidence analysis. The system using SAS/AF and SAS/SCL is the graphic user interface and the correspondence of the changed experimental circumstances

친모의 유전자형을 알 수 없을 때 친자확인 유전자 검사

황적준,이재원,한길로,이혜승 大韓法醫學會 1999 대한법의학회지 Vol.23 No.1

In parentage testing DNA profiles are used to link the alleged father with paternity by matching their patterns. The probative value of a match is often calculated by multiplying together the estimated frequencies with which each particular VNTR or STR pattern occurs in a reference population. When this calculating method applies to the motherless case of paternity disputes, a calculation must usually be based on types determined for the child and the alleged father. In such case, the first consideration is to exclude a man from paternity of a child when the man did not have the child's paternal allele at some loci, or if the paternal allele cannot be determined, when the man had neither of the child's alleles. The second is to evaluate the DNA evidence when a man is not excluded by the paternal allele. This work is to provide theories of paternity analysis with three approach methods for the motherless case, and to evaluate their efficiency compared to the trio case when the man tested is not excluded. Consequently, the motherless case offers lower probability exclusion and questionable cumulative paternity index than those of the trio case as being typed with 14 STR loci(CSF1PO, THO1, TPOX, vWA, nity index than those of the trio case as being typed with 14 STR loci(CSF1PO, THO1, TPOX, vWA, D5S818, D13S317, D7S820, D16S539, FGA, D21S11, FES/FPS, F13A1, D18S80, D17S5). Since the motherless case in paternity disputes is less efficient for paternity exclusion of the child, the use of genetic maker systems with the higher value of mean exclusion chance(MEC) and exact levels of the relative probability of paternity must be of importance considered in the analysis of such deficiency cases.