• 한국생산제조학회지
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• 제25권6호
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• pp.421-425
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• 2016

Micro-EDM is one of the recent fine-machining technologies. Micro-EDM is widely used in precision processes because products manufactured via EDM are free from workpiece hardness. However, the debris produced during the process cause many problems such as reduced precision of the process. The first solution of this problem involves using the milling hole process. Micro-EDM hole process involves an electrode moving rapidly in the vertical direction via a servo system to disperse debris. However, this process can cause reduced work efficiency owing to contact between the electrode and workpiece. In this study, ultrasonic vibration is added to micro-EDM channel machining. Ultrasonic vibration removes the debris during machining and enables precision machining. Consequently, a clean work environment for the subsequent processes is maintained.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.567-567
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• 2003

The purpose of this study was to evaluate the effect of multiple application of all-in-one dentin adhesive system on microtensile bond strength using confocal laser scanning microscope and microtensile bond strength test. The dentin surface of human molars, sectioned to remove the enamel from the occlusal surface were prepared. In group I, Scotchbond Multipurpose(SM, 3M ESPE) was applied by manufature's recommended. In group II, after the all-in-one adhesive, Adper Prompt L-Pop was applied for 15s, and light cured for 10s, the second coat was re-applied and light-cured.(omitted)

• Medical Lasers
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• 제9권1호
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• pp.25-33
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• 2020

Optical-based imaging technology has high resolution and can assess images in real time. Numerous studies have been conducted for its application in the dental field. The current research introduces an oral camera that includes fluorescent imaging, a second study examining a 3D intraoral scanner applying a confocal method and a polarization structure that identifies the 3D image of a tooth, and finally, an optical coherence tomography technique. Using this technique, we introduce a new concept 3D oral scanner that simultaneously implements 3D structural imaging as well as images that diagnose the inside of teeth. With the development of light source technology and detector technology, various optical-based imaging technologies are expected to be applied in dentistry.

• 천문학회보
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• 제44권2호
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• pp.79.1-79.1
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• 2019

The Schwarzchild-Chang telescope is a confocal off-axis two mirror telescope with D = 50 mm, F = 100 mm and FOV = 8 ° × 8 °. Unlike common off-axis telescopes, the mirrors of the Schwarzchild-Chang telescope share their focal points to remove the linear astigmatism. In this poster, we show the alignment process of the Schwarzchild-Chang telescope with wavefront measurement and the sensitivity table method. Wavefront is measured using the Shack-Hartmann sensor, and Zernike polynomials are obtained from measured wavefront. Sensitivity table method is to calculate alignment errors from the Zernike coefficients. As a result, we evaluate tilt, decenter, and despace of each mirror of linear astigmatism-free con-focal off-axis system.

• Restorative Dentistry and Endodontics
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• 제24권2호
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• pp.310-321
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• 1999

In this in vitro study, confocal laser scanning microscopic morphology of dentin-resin interface and its relationship to shear bond strength were investigated after the exposed dentin surfaces were treated with 3 different kinds of dentin adhesive systems[three-step; Scotchbond Multi-Purpose Plus(SMPP), self-priming bonding resin; Single Bond(SB), self-etching primer; Clearfil Liner Bond 2(LB2)]. 52 extracted human molar teeth without caries and/or restorations. The experimental teeth were randomly divided into three groups of seventeen teeth each. In five teeth of each group, class V cavities(depth: 1.5mm) with 900 cavosurface angles were prepared at the cementoenamel junction on buccal and lingual surfaces. Bonding resins of each dentin adhesive system were mixed with rhodamine B. Primer of SMPP was mixed with fluorescein. In group 1. the exposed dentin was conditioned with etchant, applied with above primer and bonding resin of SMPP. In group 2, with etchant and self-priming bonding agent of SB. In group 3, with self-etching primer and bonding agent of LB2. After treatment with dentin adhesive systems, composite resin were applied and photocured. The experimental teeth were cut longitudinally through the center line of restoration and grounded so that about $90{\mu}m$-thick wafers of buccolingually orientated dentin were obtained. And, $70{\sim}80{\mu}m$-thick wafers sectioned horizontally, thus presenting a dentinal tubules at 900 to the cut surface of a remaining tooth, were obtained. Primer of SMPP mixed with rhodamine B was applied to these wafers. Confocal laser scanning microscopic investigations of these wafers were done within of 24 hours after treatment. To measure shear bond strength, the remaining twelve teeth of each group were grounded horizontally below the dentinoenamel junction, so that no enamel remained. After applying dentin adhesive systems on the dentin surface, composite was applied in the shape of cylinder. The cylinder was 5mm in diameter, and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. It was concluded as follows ; 1. Hybrid layer of SMPP(mean: $4.56{\mu}m$) was thicker than that of any other groups. This value was not statistically significant thicker than that of SB(mean: $3.41{\mu}m$, p>0.05), and significant thicker than that of LB2(mean: $1.56{\mu}m$, p<0.05). There was a statistical difference between SB and LB2(p<0.05). 2. Although there were variations in the length of resin tag even in a sample, and in a group, most samples in SMPP and SB showed resin tags extending above $20{\mu}m$. But samples in LB2 showed resin tags of $10{\mu}m$ at best. 3. Besides primer's infiltration into demineralized peritubular dentin and dentinal tubules, fluorophore of primer was detected in the lateral branches of dentinal tubules. 4. All groups demonstrated statistically significant differences from one another(p<0.05), with shear bond strengths given in descending order as follows: SMPP(18.3MPa), SB(16.0MPa) and LB2(12.4MPa). 5. LB2 having thinnest hybrid layer($1.56{\mu}m$) showed the lowest shear bond strength(12.4MPa).

• 한국식품위생안전성학회지
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• 제16권3호
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• pp.232-240
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• 2001

시장에서 수집한 갈변병에 감염된 느타리버섯으로부터 125 균주를 분리하였고 그 중 45 균주는 병원성 균주로 조사되었다. WLFO 6 strains, WLFO 6 strains으로 나타났고, WLRO의 몇 균주는 병원성 검정 실험에서 약한 병원성을 나타내기도 했다. WLFO 6균주는 모두 느타리버섯의 갈변병 주원인균으로 알려진 P. tolaasii로 미생물 신속 동성을 (MIDI, gas chromatograph-microbial identification system)에 의해 동정되었고 WLRO는 P. gingeri, P. fluorescens biotype A and type C. 로 동정되었다. 그 외의 선발된 Pseudomonas spp.는 P. gingeri, P. agarici, P. fluorescens biotype B, P. chloroaphis, non-pathogenic P. tolaasii, P. putida biotype A, B 등으로 동정이 되었다. 분리된 병원성 세균의 세포배양 여과액으로 버섯에서의 갈변과 조직 함몰을 실험하였다. 병원성 검정에서 약한 병원성을 보인 분리균들은 갈변 또는 조직함몰이 나타나지 않았으나 강한 병원성을 나타냈던 균들은 두 현상이 모두 나타났다. P. tolaasii에 의해서 생성되는 세포외독소인 tolaasin의 활성을 조사하기 위하여 600 nm에서 용혈 활성을 측정하였다. P. tolaasii로 동정된 6 균주는 0.8∼0.9, 약한 병원성의 WLROs는 0.9∼1.0 그리고 Pseudomonas spp.는 10∼1.2로 나타났다. 공초점 현미경 기술을 이용하여 신선한 버섯에서의 조직을 optical sectioning image와 vertical sectioning image로 관찰하였고 또한 P. toiaasii에 의하여 오염된 조직부위의 영상을 회득하였다.

• 한국광학회지
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• 제17권1호
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• pp.47-53
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• 2006

미국 등 세계 여러 나라에서 사용되는 기존의 총기 인식 시스템(Integrated Ballistic Identification System)은 탄흔을 2차원 현미경을 통해 측정, 해석하기 때문에 여러 가지 한계를 가지고 있다. 대표적으로 측정 표면의 거칠기나 기울기 성분, 빛의 조명 각도, 조명 광량의 균일 정도, 표면의 다중 반사나 광학적 특성에 의해 측정 결과가 크게 영향을 받는다. 이로 인해 부정확한 해석을 할 수밖에 없고, 결국 총기 인식 결과의 신뢰성이 떨어진다. 본 연구에서는 이와 같은 단점을 극복하기 위해 조명이나 표면 조건에 영향을 적게 받는 삼차원 형상 측정을 도입했다. 대표적으로 백색광 주사간섭계와 동초점현미경이 사용되었으며, 이런 측정기들은 미국 표준연구소 (National Institute of Standards and Technology, NIST)의 교정 단계를 밟아 보정했다. 그 결과 반복성과 재현성이 뛰어난 측정 결과를 얻을 수 있었다. 또한 본 논문에서 제안하는 3차원 형상 비교 알고리즘을 통해 보다 높은 신뢰도를 갖는 총기 인식이 가능해졌다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.282-285
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• 2001

질산화 생물여과 시스템 내 생물막 안에 존재하는 ammonia oxidizers 및 nitrite oxidizers의 군집 구조 및 공간적 분포를 조사하였다. FISH 분석 결과 생물막 내 숫적으로 우점종을 이루는 미생물은 ammonia oxidizer인 Nitrosomonas spp.로 나타났으며 nitrite oxidizer 인 Nilrospira spp.에 비해 3 ${\sim}$ 5 정도 더 많이 존재하였다. 이는 실협 기간동안 완전한 질산화를 보였지만 반응기가 2 년 이상 nitrite 축적을 위해 높은 free ammonia 농도 빛 낮은 용존 산소 상태에서 운선되어 nitrite oxidizers에 저해를 주었기 때문인 것으로 사료된다. FISH와 결합된 CLSM 관찰 결과 생물막 전체에 걸쳐 ammonia oxidizer가 분포하는 반면 안쪽으로 갈수록 nitrite oxidizers가 분포함을 보였다. 이는 폐수의 ammonium 을 생물막 내 ammon ia oxidizer가 먼저 nitrite로 산화시키고 이를 nitrite oxidizers가 곧바로 nitrate로 산화시키기 때문이다.

• 대한의용생체공학회:의공학회지
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• 제28권4호
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• pp.471-476
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• 2007

Various active microwave imaging techniques have been developed for cancer detection for past several decades. Both the microwave tomography and the UWB radar techniques, constituting functional microwave imaging systems, use the electrical property contrast between normal tissues and malignancies to detect the latter in an early development stage. Even though promising simulation results have been reported, the understanding of the functional microwave imaging diagnostics has been relied heavily on the complicated numerical results. We present a computationally efficient and physically instructive analytical electromagnetic wave channel models developed for functional microwave imaging system in order to detect especially the breast tumors as early as possible. The channel model covers the propagation factors that have been examined in the previous 2-D models, such as the radial spreading, path loss, partial reflection and transmission of the backscattered electromagnetic waves from the tumor cell. The effects of the system noise and the noise from the inhomogeneity of the tissue to the reconstruction algorithm are modeled as well. The characteristics of the reconstructed images of the tumor using the proposed model are compared with those from the confocal microwave imaging.

• The Korean Journal of Physiology and Pharmacology
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• 제9권6호
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• pp.363-369
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• 2005

It is imperative to analyse brain injuries directly in real time, so as to find effective therapeutic compounds to protect brain injuries by stress. We established a system which could elucidate the real time $Ca^{2+}$ dynamics in an organotypic cultured hippocampal slice by the insults of artificial stress hormone, dexamethasone. The real time $Ca^{2+}$ dynamics could continuously be detected in cornus ammonis 3 (CA3) of the organotypic hippocampus for 8 hours under confocal microscopy. When dexamethasone concentration was increased, the $Ca^{2+}$ was also increased in a dose dependent manner at $1{\sim}100{\mu}M$ concentrations. Moreover, when the organotypic cultured hippocampal slice was treated with a glutamate receptor antagonist together with dexamethasone, the real time $Ca^{2+}$ dynamics were decreased. Furthermore, we confirmed by PI uptake study that glutamate receptor antagonist reduced the hippocampal tissue damage caused by dexamethasone treatment. Therefore, our new calcium ion dynamics system in organotypic cultured hippocampal slice after dexamethasone treatment could provide real time analysis method for investigation of brain injuries by stress.