• 대한핵의학회지
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• 제32권4호
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• pp.365-373
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• 1998

목적: 일반 감마카메라는 그 크기(${\sim}500mm$ 폭)가 전신영상 획득에 적합하도록 설계되어있어 유방영상 획득에는 비 이상적이다. 이 연구의 목적은 물리적 영상 저하요인인 배후 방사능과 광자감쇠 효과를 최소화하여 높은 공간분해능과 시스템 민감도를 가지며 유방영상에 적합하도록 소형화된 저가-고성능유방암 진단전용 소형 감마카메라 개발이다. 대상 및 방법: 크기가 $60 mm{\times}60 mm{\times}6 mm$인 NaI(T1) 섬광결정을 위치민감형 광전자증배관에 접합시켜 감마선 측정신호인 $X^+,\;X^-,\;Y^+,\;Y^-$를 얻은 다음, 증폭기 등을 포함한 전자회로(nuclear instrument modules, NIM)를 통하여 검출기로부터 발생하는 위치신호와 트리거 신호를 처리하였다. 이 신호들을 아날로그-디지털 변환기와 앵거로직을 사용하여 분석한 후 감마카메라 영상을 구성하여 일반 개인용컴퓨터에 표현하는 시스템을 개발하였다. 개발된 감마카메라의 1차적인 성능을 평가하기 위해 Tc-99m 점선원을 이용하여 내인성 계수율과 플러드 영상을 획득하였다. 또한 일정간격의 구멍이 있는 구멍 마스크와 직경 2, 3, 4, 5, 6, 7 mm 크기의 구모양에 방사능 용액을 채울 수 있는 유방모형을 제작하여 평행구멍형조준기를 장착하고 영상을 획득하였다. 결과: 개발된 감마카메라는 약 $8{\times}10^3 counts/sec/{\mu}Ci$의 계수율을 보였으며, 공간왜곡은 관찰되나 양질의 플러드 영상과 구멍 마스크 영상을 획득할 수 있었고, 유방모형에 위치한 방사능 분포를 정확하게 영상화할 수 있을 뿐 아니라 최소 2 mm의 방사능 위치를 판별할 수 있는 영상을 획득하였다. 결론: NaI(T1)-위치민감형 광전자증배관를 이용하여 유방영상에 적합한 소형감마카메라를 개발하였다. 추후 선형성, 장균일도 및 불응시간에 대한 보정 알고리즘을 완성하여 적용하고, 정상작동 여부를 검사하기 위한 정도관리 방법을 설정하면, 유방 신티그라피의 정확도를 높이는데 기여할 것이다.

• 대한기계학회논문집
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• 제10권3호
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• pp.357-366
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• 1986

본 연구에서는 3공피토우관 및 열선유속계를 사용하여 벽에 평행한 2차원 난류제트의 난류량들을 측정하였고, 스캐니 밸브를 이용하여 벽면아력분포를 측정함 으로써 재순환 영역을 포함한 전체유동장에서의 유동특성을 고찰하였다. 또한 잘 알려진 표준 k-.epsilon. 난류모형 및 유선곡률을 고려한 수정된 k-.epsilon. 난류모형을 이용하여 측정 수치해석을 수행하였다.

• 한국동물위생학회지
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• 제18권2호
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• pp.163-176
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• 1995

Triphenyl Tetrazolium Chloride(TCC) reduction test is simple and sensitive to some residual antibiotics (especially to penicillin) in milk, but comparatively insensible to sulfo-namides. The volumn of sample is also large. Thus this study was undertaken to increase the detectable level of sulfonamides in raw milk. In this study, we used small transparent plastic hole and pulp disc instead of 10m1 test tube and made test medium in which was added 0.08%TTC, 0.3% agar, 10% skim milk, approximately $10^6$ CFU/ml streptococcus thermophilus and 5ppm Trimethoprim to enhance the sensitivity for sulfonamides The results of TCC reduction test by disc plate method were summarized as follows : 1. sensitivity to residual sulfonamides were much higher than official TCC reduction test. Detectable limites of sulfamethazine, sulfamerazine, sulfathiazole, sulfachloropy-ridazine, sulfadimethoxine, sulfamononethoxine, sulfadiazine and sulfaquinoxaline were 0.1-0.5ppm levels. 2. Detectable limites to some antibiotics were simillar or good than that of official method as 0.005-0.1ppm to three ${\beta}$ -lactams, 0.25-0.5ppm to one macrolide, 2-10ppm to three aminoglycosides, 0.2-0.5ppm to three tetracycline, 0.1-0.5ppm to chloramphenicol. 3. Only 0.1ml of milk was needed to test and the test medium could be stored appnoximatly 7days in the refrigerator. So test procedure was convenient than offcial method. 4. These results suggest that disc plate method is more useful to detect bacterial growth inhibition substances including sulfonamides in raw milk.

• Applied Microscopy
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• 제10권1_2호
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• pp.7-17
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• 1980

Electron microscope radioautography introduced by Liquier-Milward (1956) is now used routinely in many laboratories. Most of the technical difficulties in specimen preparation have been overcome. This method is modified from loop method for improvement of EM radioautographic techniques. The advantages of this method are: 1. the use of single specimens on small corks and of a large wire loop, allows the experimenter to avoid the blemishes in the membrane; 2. the surfactant dioctyl sodium sulphosuccinate is added to diluted ILford L4, thus greatly prolonging the period of time over which good emulsion layers can be made; 3. corks can be handled in perspex holder which allows about 20 specimens to be developed simultaneously. The steps of the method comprise: 1. Cut ribbons of ultrathin sections of silver interference colour 2. Pick them up on formvar-coated 200 mesh grids 3. Prestaining of tissues 4. Coat the specimens with a thin layer of carbon by evaporation (30-60A) 5. Mount the specimens on corks (about 1cm apical diameter) using double-sided scotch tape 6. Emulsion coating; a. Take a 250m1 beaker, place it on the pan of a sliding weight balance and weigh it. Add 10 grams extra to the beam. Add pieces of ILford L4 emulsion to the beaker until the balance is swinging freely. Add the 20ml of distilled water that was previously measured out. b. Surfactant dioctyl sodium sulphosuccinate is added to diluted ILford L4. 7. Prepare a series of membranes of gelled emulsion with the wire loop and apply one to each cork-borne specimen. 8. Put the specimens away to expose by pushing the corks into short length of PVC tubing, each tube having a small hole in the side 9. Place the tubes in small boxes together with silica gel. 10. Exposure 11. Developer - Kodak Microdol X for 3 minutes 12. Fixer - A perspex holder can be manufactured which allows 20 specimens to be developed simultaneously. 12. Fixer - 30% sodium thiosulfate for 10 minutes 13. Examination with Siemens Elmiskop 1A electron microscope

• Journal of Magnetics
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• 제19권3호
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• pp.248-254
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• 2014

The purpose of this study is to figure out how uptake counts of technetium ($^{99m}Tc$) among radioisotopes in the human body are affected if computed tomography (CT), magnetic resonance imaging (MRI) and isotope examination are performed consecutively. $^{99m}Tc$ isotope material, iodinated contrast media for CT and paramagnetic contrast media for magnetic resonance (MR) were used as experimental materials. First, $^{99m}Tc$ was added to 4 cc normal saline in a test tube. Then, 2 cc of CT contrast media such as $Iopamidol^{(R)}$ and $Dotarem^{(R)}$ were diluted with 2 cc normal saline, and 2cc of MRI contrast media such as $Primovist^{(R)}$ and $Gadovist^{(R)}$ were diluted with 2 cc normal saline. Each distributed contrast media was a total of 4 cc and included 10m Ci of $^{99m}Tc$. A gamma camera, a LEHR (Low energy high resolution) collimator and a pin-hole collimator were used for image acquisition. Image acquisition was repeated a total of 6 times and 120 frames were obtained and uptake counts of $^{99m}Tc$ were measured (from this procedure). In this study, as a result of measuring the uptake counts of $^{99m}Tc$ using the LEHR collimator, the uptake counts were less measured in all contrast media than normal saline as a reference. In particular, the lowest uptake counts were measured when $Gadovist^{(R)}$, contrast media for MRI, was used. However, the result of measuring the uptake counts of $^{99m}Tc$ using the pin-hole collimator showed higher uptake counts in all contrast media, except for $Iopamidol^{(R)}$, than normal saline as a reference. The highest uptake counts were measured particularly when $Primovist^{(R)}$, contrast media for MRI, was used. In performing the gamma camera examination using contrast media and $^{99m}Tc$, it is considered significant to check the changes in the uptake counts to improve various diagnosis values.

• 한국지열·수열에너지학회논문집
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• 제8권2호
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• pp.36-47
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• 2012

Time-series variation of groundwater temperature in Mongolia shows that maximum temperature is occured from end of October to the first of February(winter time) and minimum temperature is observed from end of April to the first of May(summer time). Therefore ground temperature is s a good source for space heating in winter and cooling in summer. Groundwater temperatures monitored from 3 alluvial wells in Ulaabaatar at depth between 20 and 24 m are $(4.43{\pm}0.8)^{\circ}C$ with average of $4.21^{\circ}C$ but mean annual ground temperature(MAGT) at the depth of 100 m in Ulaanbaatar was about $3.5{\sim}6.0^{\circ}C$. Bore hole length required to extract 1 RT's heat energy from ground in heating time and to reject 1 RT's heat energy to ground in summer time are estimated about 130 m and 98 m respectively. But in case that thermally enhanced backfill and U tube pipe placement along the wall are used, the length can be reduced about 25%. Due to low MAGT of Ulaabaatar such as $6^{\circ}C$, the required length of GHX in summer cooling time is less than the one of winter heating time. Mongolia has enough available property, therefore the most cost effective option for supplying a heating energy in winter will be horizontal GHX which absorbs solar energy during summer time. It can supply 1 RT's ground heat energy by 570 m long horizontally installed GHX.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 제7회 특별심포지움 논문집
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• pp.83-92
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• 2005

연안지역에서 해수침투대의 특성을 파악하기 위하여 전기전도도 검층을 수행하였다. 검층의 목적은 투수성 파쇄대 및 고염분 지하수가 유입되는 구간의 확인이다. 전기전도도 검층은 시추공 내의 지하수를 전기적으로 다른 성질을 갖는 지하수로 치환하고 일정 양수 또는 자연 상태에서 시간에 따른 전기전도도의 변화를 측정한다. 따라서 시추공과 교차하는 투수성 파쇄대 또는 다공성의 대수층에서 시추공내로 유입되는 지층수 전기전도도의 변화 특성을 일정 시간 간격에 따라서 측정하면 지하수가 유입되는 구간의 확인이 가능하다. 현장 시험에 적용한 공내수 치환 시스템은 주입과 양수, 유량측정이 가능하며 내경이 작은 모니터링 PVC 케이싱도 적용이 가능하도록 제작하였다. 전남 영광의 연안지역에 위치하는 3개 시추공에 공내수 치환기법을 적용하여 전기전도도의 변화 특성을 측정한 결과, 연안지역의 고염분지하수는 균열암반을 통한 해수침투는 물론 간척사업으로 인한 잔류염분의 영향을 동시에 받고 있음을 확인할 수 있었다. 공내수 치환기법과 추가적으로 수행될 정량적인 해석 결과는 연안지역에서 수리상수 추정, 최적의 양수설계, 해수침투 특성 평가 등에 활용될 것으로 예상된다.

• 대한조선학회논문집
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• 제51권4호
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• pp.311-320
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• 2014

Test uncertainty of a towed underwater Stereoscopic Particle Image Velocimetry (SPIV) system was assessed in a towing tank. To estimate the systematic error and random error of mean velocity and turbulence properties measurement, velocity field of uniform flow was measured. Total uncertainty of the axial component of mean velocity was 1.45% of the uniform flow speed and total uncertainty of turbulence properties was 3.03%. Besides, variation of particle displacement was applied to identify the change of error distribution. In results for variation of particle displacement, the error rapidly increases with particle movement under one pixel. In addition, a nominal wake of a model ship was measured and compared with existing experimental data by five-hole Pitot tubes, Pitot-static tube, and hot wire anemometer. For mean velocity, small local vortex was identified with high spatial resolution of SPIV, but has serious disagreement in local maxima of turbulence properties due to limited sampling rate.

• 한국지반환경공학회 논문집
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• 제20권5호
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• pp.31-38
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• 2019

최근 도심지에서 지반함몰의 발생이 증가하고 있으며, 이러한 경우 신속한 복구를 통해 안전사고 및 통행에 대한 불편을 최소화하는 것이 중요하다. 현재의 지반함몰 복구 방법으로는 함몰지반을 개착한 후에 되메우기를 하거나 그라우팅 주입재를 사용하여 지반을 복구하는 방법이 주로 적용되고 있으나. 지반 함몰복구 시 사용되는 재료에 대한 연구는 미비한 실정이다. 따라서 본 연구에서는 함몰지반에 사용되는 되메움재료의 특성을 규명하기 위하여 준설점토를 친환경 고화재를 이용하여 개량한 후 고화재의 혼합비율 및 화강풍화토의 혼합비율을 변화시켜 3, 7, 14, 28일 양생시킨 후 일축압축 강도특성을 분석하였으며, 기존에 사용되던 고화재인 시멘트의 일축압축강도와 비교하였다. 되메움재료의 강도특성을 평가하기 C.B.R 시험을 수행하였고, 되메움 재료가 상하수도관 등의 부식에 영향을 주는지에 대한 검토를 위하여 토양비저항시험을 수행하였다. 시험결과 긴급을 요하는 함몰지반 복구공사의 경우 12%의 고화재를 혼합하여 3일 이상 양생하는 것이 좋다고 판단되며, 가스관이나 상하수도관의 부식에 영향을 미치지 않도록 하기 위하여 화강풍화토를 30% 이상 혼합할 것을 제안한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권1호
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• pp.3-10
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• 2014

Objectives: Although nerve growth factor (NGF) could promote the functional regeneration of an injured peripheral nerve, it is very difficult for NGF to sustain the therapeutic dose in the defect due to its short half-life. In this study, we loaded the NGF-bound heparin-conjugated fibrin (HCF) gel in the NGF-delivering implants and analyzed the time-dependent release of NGF and its bioactivity to evaluate the clinical effectiveness. Materials and Methods: NGF solution was made of 1.0 mg of NGF and 1.0 mL of phosphate buffered saline (PBS). Experimental group A consisted of three implants, in which $0.25{\mu}L$ of NGF solution, $0.75{\mu}L$ of HCF, $1.0{\mu}L$ of fibrinogen and $2.0{\mu}L$ of thrombin was injected via apex hole with micropipette and gelated, were put into the centrifuge tube. Three implants of experimental group B were prepared with the mixture of $0.5{\mu}L$ of NGF solution, $0.5{\mu}L$ HCF, $1.0{\mu}L$ of fibrinogen and $2.0{\mu}L$ of thrombin. These six centrifuge tubes were filled with 1.0 mL of PBS and stirred in the water-filled beaker at 50 rpm. At 1, 3, 5, 7, 10, and 14 days, 1.0 mL of solution in each tubes was collected and preserved at $-20^{\circ}C$ with adding same amount of fresh PBS. Enzyme-linked immunosorbent assay (ELISA) was done to determine in vitro release profile of NGF and its bioactivity was evaluated with neural differentiation of pheochromocytoma (PC12) cells. Results: The average concentration of released NGF in the group A and B increased for the first 5 days and then gradually decreased. Almost all of NGF was released during 10 days. Released NGF from two groups could promote neural differentiation and neurite outgrowth of PC12 cells and these bioactivity was maintained over 14 days. Conclusion: Controlled release system using NGF-HCF gel via NGF-delivering implant could be an another vehicle of delivering NGF to promote the nerve regeneration of dental implant related nerve damage.