• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.4 no.2
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• pp.38-45
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• 1995

The diagnosis and monitoring system of abnormal cutting condition is necessary to realize precision machining proces and factory automation, which are final goal of metal cutting in order to develop this system, theimage processing technique has been investigated in machining process. In theis paper, the measurement system of tool wear using computer vision is designed to detect the wear pattern by non-contact and direct method and get the realiable wear information about cutting tool. We measured the area of the side and front part of the diamond core dril which is used in 40kHz ultrasonic vibration machine.

• CDE review
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• v.3 no.1
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• pp.50-51
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• 1997

CYL/HEAD제작에 있어서 DIGITAL MOCK-UP의 효과는 다음과 같다. 1. PATTERN에서 가상 몰드를 만들어 몰드의 장, 탈착성을 검토할 수 있고 각 몰드 및 전체중량을 산출할 수 있기 때문에 최적의 PARTING을 할 수 있다. 2. 가상 몰드의 조립에 의해서 가상 주물형을 만들 수 있기 때문에 생산하기 전에 실물의 내, 외부의 정확한 형상을 알 수가 있다. 즉 주물공정상 외형부분과 CORE 부분의 형상을 따로 만들기 때문에 형상을 잘못 만들었든가 몰드 조립을 잘못 했든가 하는 등의 이유로 간혹 두께가 맞지 않은 경우가 있는데 SECTION 확인에 의해서 외형부분과 CORE 가장자리에 두께가 제대로 되어 있는지 알 수가 있으므로 오류를 줄일 수 있다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.3
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• pp.274-287
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• 1984

밀폐용기 내의 자연대류에 의한 흐름현상에 고유하며 아직까지 해결되지 않고 있는 중요한 문제 는 그 내부흐름의 형태를 주어진 물리적인 조건으로부터 미리 예측할 수 없다는 것이다. 이는 이 문제의 해석적인 해결에 가장 큰 난점이 되고 있다. 본 논문에서는 multiple scales method를 이 용한 해석적인 모델을 개발하여 종횡비가 낮은 직각형 밀폐용기 내에서 운동력이 코어에 존재하 는 경우 그 내부 흐름형태를 scaling analysis를 통해 정성적으로 예측, 기존의 결과와 비교 검토 하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.320-326
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• 2008

In this paper, we propose a new algorithm emulating the DNA characteristics for noise-tolerant pattern matching problem on digital system. The digital pattern matching becomes core technology in various fields, such as, robot vision, remote sensing, character recognition, and medical diagnosis in particular. As the properties of natural DNA strands allow hybridization with a certain portion of incompatible base pairs, DNA-inspired data structure and computation technique can be adopted to bio-signal pattern classification problems which often contain imprecise data patterns. The key feature of noise-tolerance of DNA computing comes from control of reaction temperature. Our hardware system mimics such property to diagnose cardiovascular disease and results superior classification performance over existing supervised learning pattern matching algorithms. The hardware design employing parallel architecture is also very efficient in time and area.

• Nuclear Engineering and Technology
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• v.20 no.1
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• pp.9-18
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• 1988

Previously determining the fuel loading pattern is based on the trial and error method. For a candidate pattern, the core analysis is performed and the pattern is examined whether it satisfies the imposed constraints such as the power peaking or not. The pattern, then, is revised by the shuffling of assemblies and the revision is repeated until all of the conditions are met. This method unavoidably requires many iterative diffusion calculations, computing times and accumulated experiences. To overcome these disadvantages, a new method which is called backward diffusion calculation is introduced. If the most desirable power distribution is already known, the optimal loading pattern can be obtained by solving the backward diffusion equation with simple calculation. In this study, the basic equation for the backward diffusion calculation is derived and the optimal power and fuel distributions are searched in one-dimensional cylindrical geometry by using the proposed method. In addition, the basis to determine the optimal power and fuel distributions is suggested for the real core geometry.

• Journal of Life Science
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• v.22 no.2
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• pp.245-250
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• 2012

The 16S rDNA - RFLP types for six Vibrio species (V. fluvialis, V. proteolyticus, V. vulnificus, V. mimicus) including two core group members, V. alginolyticus and V. parahaemolyticu s, and Grimontia (Vibrio) hollisae were determined using PCR-RFLP analysis. Six tetrameric restriction enzymes (Alu I, Cfo I, Dde I, Hae III, Msp I, and Rsa I) were selected for RFLP analysis. V. alginolyticus, V. parahaemolyticus, and V. proteolyticus showed the same RFLP pattern following digestion with four of the six used restriction enzymes: CfoI, DdeI, MspI, and RsaI. Various restriction enzyme combinations generated digests recognizable as distinct RFLP types for each of the assayed Vibrio species. In particular, AluI single digestion produced species specific band patterns that enabled the differentiation between these Vibrio species. Dendrogram based on restriction patterns showed that two Vibrio core group members, V. alginolyticus and V. parahaemolyticus were closely related having a similarity over 90%. Although the observed RFLP pattern for Grimontia hollisae shared several common bands with other Vibrio spp., G. hollisae results were still clearly distinct from Vibrio spp. RFLP types for all restriction enzymes tested. If restriction enzymes are aptly selected, PCR-RFLP analysis is still a rapid and effective tool for differentiating Vibrio species.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.2
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• pp.55-59
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• 2015

Novel low-volume solder-on-pad (SoP) process is proposed for a fine pitch Cu pillar bump interconnection. A novel solder bumping material (SBM) has been developed for the $60{\mu}m$ pitch SoP using screen printing process. SBM, which is composed of ternary Sn-3.0Ag-0.5Cu (SAC305) solder powder and a polymer resin, is a paste material to perform a fine-pitch SoP in place of the electroplating process. By optimizing the volumetric ratio of the resin, deoxidizing agent, and SAC305 solder powder; the oxide layers on the solder powder and Cu pads are successfully removed during the bumping process without additional treatment or equipment. The Si chip and substrate with daisy-chain pattern are fabricated to develop the fine pitch SoP process and evaluate the fine-pitch interconnection. The fabricated Si substrate has 6724 under bump metallization (UBM) with a $45{\mu}m$ diameter and $60{\mu}m$ pitch. The Si chip with Cu pillar bump is flip chip bonded with the SoP formed substrate using an underfill material with fluxing features. Using the fluxing underfill material is advantageous since it eliminates the flux cleaning process and capillary flow process of underfill. The optimized interconnection process has been validated by the electrical characterization of the daisy-chain pattern. This work is the first report on a successful operation of a fine-pitch SoP and micro bump interconnection using a screen printing process.

• Journal of the Korean Ceramic Society
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• v.55 no.1
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• pp.55-60
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• 2018

In this study, quantum dots composed of $Mn^{2+}$ doped ZnS core and ZnS shell were synthesized using MPA precursor at room temperature. The ZnS: Mn/ZnS quantum dots were prepared by varying the content of MPA in the synthesis of ZnS shells. XRD, Photo-Luminescence (PL), XPS and TEM were used to characterize the properties of the ZnS: Mn/ZnS quantum dots. As a result of PL measurement using UV excitation light at 365 nm, the PL intensity was found to greatly increase when MPA was added at 15 ml, compared to the case with no MPA; the PL peaks shifted from 603 nm to 598 nm. A UV sensor was fabricated by using a sputtering process to form a Pt pattern and placing a QD on the Pt pattern. To verify the characteristics of the sensor, we measured the electrical properties via irradiation with UV, Red, Green, and Blue light. As a result, there were no reactions for the R, G, and B light, but an energy of 3.39 eV was produced with UV light irradiation. For the sensor using ZnS: Mn/ZnS quantum dots, the maximum current (A) value decreased from $4.00{\times}10^{-11}$ A to $2.62{\times}10^{-12}$ A with increasing of the MPA content. As the MPA content increases, the PL intensity improves but the electrical current value dropped because of the electron confinement effect of the core-shell.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.225-233
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• 1994

The restorations of the severely damaged teeth by post core have been increased with the developement of endodontic procedures. But high failure rates of these procedures being reported, various restorative modifications were induced for successful treatments. Cast post-core and prefabricated post with core buildups are choice of treatment. The main causes of failure of the restorations are the fracture of post and core, root fracture, and recurrent caries due to microleakage. Recently, the acid etching technique and the use of dentin bonding agent at tooth surface to reduce the possible microleakage at the tooth-restoration interfaces were introduced. The object of this study was to measure and compare the microleakage by the types and cementation methods of post-core. For this study, forty extracted human anterior teeth were selected for specimen. After cleansing and routine endodontic procedures, anatomic crowns of each specimen were removed at the level of 2mm above the cementoenamel junction. Canals were preparated for post insertion and specimens were divided into four groups randomly. Post-cores were fabricated according to method for each group. Microleakage was measured by length of dye penetration at the tooth-restoration interfaces with measuring microscope at 50 magnification. Oneway ANOVA and t-test were performed for statistical analysis of resulting data. The following results were obtained from this study. 1. There wert significant statistical differences in degree of microleakage between each group (p<0.01). 2. Cast post-core cemented with ZPC (Group I) showed the most severe microleakage pattern$(1.5547{\pm}0.0872mm)$, and cast post-core cemented with adhesive resin cement after tooth surface treatment with dentin bonding agent (Group II) showed the least microleakage $(0.1497{\pm}0.0872mm)$. 3. Group IV revealed less dye penetrations than group III, but no statistical significance was seen between two groups.

• Polymer(Korea)
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• v.26 no.2
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• pp.227-236
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• 2002

The structure of pregel state in thermoreversible poly(vinylidene fluoride)(PVDF) /propylene carbonate(PC) system was investigated by laser light scattering. It was found that the PVDF chain did not exist as a separate chain even in a very dilute concentration(i.e. 100 times more dilute than the gel formation concentration) but as a large spherical aggregate with the radius of gyration $R_G$, of 232 nm and the effective hydrodynamic radius $R_H$= of 407 nm at $40^{\circ}C$. Based upon experimental results such as $R_H/R_G$=ratio of 1.75 and the pattern of scattering intensity with a minimum, a core-shell type sphere model was suggested as a structure of the aggregate. According to this model, the radius of core part was estimated as 215 nm, the shell thickness as 192 nm, and the ratio of monomer density of the shell part to that of the core part as about 0.075.