• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.34.1-34.1
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• 2009

1970년대 WernerKern에 의해서 개발된 RCA 습식 세정 공정은 이후 메가소닉 기술 개발과 더불어 현재까지반도체 세정 공정에서 필수 공정으로 알려져 있다. 하지만, 반도체패턴의 고집적화 미세화에 따라 메가소닉을 기반으로 하는 세정기술은 패턴 붕괴 및 나노 입자 제거의 한계를 드러내면서 난관에 봉착하고 있으며, 특히, 기존의 Batch식에서 매엽식으로 세정 방식이 전환은 새로운 개념의 메가소닉 기술 개발을 요구하게 되었다. 메가소닉을 사용한습식 세정공정은 메가소닉에 의한 캐비테이션 효과 (Cavitation Effect)에 따른 충격파 및음압 (Acoustic Streaming)에 의한 입자제거를 주요 메커니즘으로 한다. 메가소닉 주파수와 Boundary Layer 두께는, $\delta=\surd(2v/\omega)$($\delta$=두께, v=유체속도), $\omega=2{\pi}f$ (f=주파수), 으로 표현할 수 있다. 위의 식에 따르면, 메가소닉을 이용한 세정공정에서 주파수가 높아질수록 Boundary Layer의 두께가 감소하며, 이는제거 가능한 입자의 크기가 작아짐을 의미하며, 다시말해, 1 MHz 보다 2 MHz 메가소닉 세정장비에서 미세 입자 세정에 유리함을 예상할 수 있다. 본연구에서는 매엽식 세정장비를 사용하여, 1MHz 및 2MHz 콘-타입 (Cone-Type) 메가소닉 장치를 100nm이하 세정 입자에 대한 입자 제거효율을 평가하였다. 입자 제거 효율을 평가하기 위하여, 표준 형광입자(63nm/104nm 형광입자, Duke Scientifics, USA)를각각 IPA에 분산시킨 후, 실리콘 쿠폰 웨이퍼 ($20mm{\times}20mm$)를 일정시간 동안 Dipping 한 후, 고순도 질소로 건조시켜 오염하였다. 매엽식 세정장비(Aaron, Korea)에 1MHz와 2MHz의 콘-타입메가소닉 발진기 (Durasonic, Korea)를 각각 장착하였다.입자 오염 및 세정 후 입자 개수 측정 및 오염입자의 Mapping은 형광현미경 (LV100D, Nikon, Japan)과 소프트웨어(Image-proPlus, MediaCybernetics, USA)를 사용하여 평가하였으며, Hydrophone을 사용하여 메가소닉에서 발생되는 음압의 균일도를 각 조건에서 측정하였다. 각각의 세정공정은 1MHz와 2MHz 메가소닉 발진기 각각에서 1W, 3W, 5W 파워로 1분간 처리하였으며, 매질을 초순수를 사용하였다. 104nm 형광 입자는 1MHz 와 2 MHz 메가소닉 세정기와 모든 세정 공정조건에서 약 99%의 세정효율인 반면, 63nm 형광입자의 경우는 전체적인세정 결과가 80% 대로 감소하였다. 본 연구를 통하여, 입자크기의 미세화에 따른 입자제거효율이 크게 감소 하는 것을 확인할 수 있으며, 기존 Batch식 메가소닉 대비 단시간 및 낮은 전압에서 동일 혹은높은 세정 효율을 얻었다. 다만, 1MHz와 2MHz 메가소닉에서의 세정력은 큰 차이를 관찰 할 수 없었는데, 주파수변화에 따른 세정효율 측정을 위하여 미세 입자를 사용한 추가 실험이 필요 할 것이다.

• Journal of radiological science and technology
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• v.36 no.3
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• pp.237-244
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• 2013

The purpose of this study is to compare method in the treatment of breast cancer using dose index. And, it is to find the optimized treatment technique to the patient. The phantom filled with tissue-equivalent material were used simulation and treatment as techniques of 3D-CRT, IMRT, VMAT was planned using Eclipse v10. By using HI(homogeneity index), CI(Conformity index), OED(Organ equivalent dose), EAR(Excess Absolute Risk), were assessed for each treatment plans. HI and CI of 3D-CRT, IMRT, VMAT were calculated 16.89, 11.21, 9.55 and 0.59, 0.61, 0.83. The organ average doses of Lt lung, Rt lung, liver, heart, esophagus, cord, Lt breast, trachea and stomach were 0.01 ~ 2.02 Gy, 0.36 ~ 5.01 Gy, 0.25 ~ 2.49 Gy, 0.14 ~ 6.92 Gy, 0.03 ~ 2.02 Gy, 0.01 ~ 1.06 Gy, 0.25 ~ 6.08 Gy, 0.08 ~ 0.59 Gy, 0.01 ~ 1.34 Gy, respectively. The OED, EAR of the IMRT and VMAT show higher than 3D-CRT. As the result of this study, we could confirm being higher dose index(HI, CI) in IMRT and VMAT than 3D-CRT, but doses of around normal organs was higher IMRT, VMAT than 3D-CRT.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.95-100
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• 2006

The COMS(Communication, Ocean and Meteorological Satellite) EPS(Electrical Power Subsystem) is derived from an enhanced Eurostar 3000 version. Eurostar 3000 EpS is fully autonomous operation in nominal conditions or in the event of a failure and provides a high level of reconfigure capability. This paper introduces the COMS EPS preliminary design result. COMS EPS consists of a battery, a solar arrat wing, a PSR(Power Supply Regulator), a PRU(Pyrotechnic Unit), a SDAM(Solar Array Drive Mechanism) and relay and fuse brackets. COMS EPS can offer a bus power capability of 3 kW. The solar array is made of a deployable wing with two panels. One type fo solar cells is selected ad GaAs/Ge triple junction cells. Li-ion battery is base lined with ten series cell module of five cells in parallel. PSR associated to battery and solar array wing generates a power bus fully regulated at 50 V. Power bus os centralized protection and distribution by relay and fuse brackets. PRU provides power for firing actuarors devices. The solar array wing is rotated by the SADM under control of the attitude orbit control subsystem. The control and monitoring of the EPS, especially of the battery, is performed by the PSR in combination with the on-board software.

• Journal of Biomedical Engineering Research
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• v.20 no.1
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• pp.107-113
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• 1999

The purpose of this study was to develop a miniature imaging gamma probe with high performance that can detect small or residual tumors after surgery. Gamma probe detector system consists of NaI(Tl) scintillator, position sensitive photomultiplier tube (PSPMT), and collimator. PSPMT was optically coupled with 6.5 mm thick, 7.62 cm diameter of NaI(Tl) crystal and supplied with -1000V for high voltage. Parallel hexagonal hole collimator was manufactured for characteristics of 40-mm hole length, 1.3-mm hole diameter, and 0.22 mm septal thickness. Electronics consist of position and trigger signal readout systems. Position signals were obtained with summing, subtracting, and dividing circuit using preamplifer and amplifier. Trigger signals were obtained using summing amplifier, constant fraction discriminator, and gate and delay generator module with preamplifer. Data acquisition and processing were performed by Gamma-PF interface board inserted into pentium PC and PIP software. For imaging studies, flood and slit mask images were acquired using a point source. Two hole phantom images were also acquired with collimator. Intrinsic and system spatial resolutions were measured as 3.97 mm and 5.97 mm, respectively. In conclusion, Miniature gamma probe images based on the PSPMT showed good image quality, we conclude that the miniature imaging gamma probe was successfully developed and good image data were obtained. However, further studies will be required to optimize imaging characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1355-1363
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• 2015

In order to maintain customer voltage within allowable limit($220{\pm}13V$), tap operation of SVR(step voltage regulator) installed in primary feeder could be carried out according to the scheduled delay time(30 sec) of SVR. However, the compensation of BESS(battery energy storage system) is being required because the customer voltages during the delay time of SVR have a difficultly to maintain within allowable limit when PV system is interconnected with primary feeder. Therefore, this paper presents modeling of SVR to regulate voltage with the LDC(line drop compensation) method and modeling of BESS to control active and reactive power bi-directionally. And also, this paper proposes the coordination control modeling between BESS and SVR in order to overcome voltage problems in distribution system. From the simulation results based on the modeling with the PSCAD/EMTDC, it is confirmed that proposed modeling is practical tool for voltage regulation analysis in distribution system.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.2
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• pp.103-108
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• 2012

Recently, as the prevalence of high-performance mobile devices and the application of the multimedia content are expanded, Super Resolution (SR) technique which reconstructs low resolution images to high resolution images is becoming important. And in the mobile devices, the development of the SR algorithm considering the operation quantity or memory is required because of using the restricted resources. In this paper, we propose a new single frame fast SR technique suitable for mobile devices. In order to prevent color distortion, we change RGB color domain to HSV color domain and process the brightness information V (Value) considering the characteristics of human visual perception. First, the low resolution image is enlarged by the improved fast back projection considering the noise elimination. And at the same time, the reliable edge map is extracted by using the LoG (Laplacian of Gaussian) filtering. Finally, the high definition picture is reconstructed by using the edge information and the improved back projection result. The proposed technique removes effectually the unnatural artefact which is generated during the super resolution restoration, and the edge information which can be lost is amended and emphasized. The experimental results indicate that the proposed algorithm provides better performance than conventional back projection and interpolation methods.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.273-281
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• 2019

The energy consumed by buildings among the total national energy consumption is more than 10% of the total. For this reason, Korea has adopted the zero energy building policy since 2025, and research on the energy saving technology of buildings has been demanded. Analysis of buildings' energy consumption patterns shows that lighting, heating and cooling energy account for more than 60% of total energy consumption, which is directly related to solar power acquisition and window opening and closing operation. In this paper, we have developed a low - power IoT sensor module for window system to transfer acquired information to building energy management system. This module transmits the external environment and window opening / closing status information to the building energy management system in real time, and constructs the network to actively take energy saving measures. The power used in the module is designed as an independent power source using solar power among the harvest energy. The topology of the power supply is a Buck converter, which is charged at 4V to the lithium ion battery through MPPT control, and the efficiency is about 85.87%. Communication is configured to be able to transmit in real time by applying WiFi. In order to reduce the power consumption of the module, we analyzed the hardware and software aspects and implemented a low power IoT sensor module.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.2
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• pp.71-82
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• 2022

In order to replace the sampling tensile test of products produced in the tab welding process, which is one of the automotive battery manufacturing processes, vision inspectors are currently being developed and used. However, the vision inspection has the problem of inspection position error and the cost of improving it. In order to solve these problems, there are recent cases of applying deep learning technology. As one such case, this paper tries to examine the usefulness of applying Faster R-CNN, one of the deep learning technologies, to existing product inspection. The images acquired through the existing vision inspection machine are used as training data and trained using the Faster R-CNN ResNet101 V1 1024x1024 model. The results of the conventional vision test and Faster R-CNN test are compared and analyzed based on the test standards of 0% non-detection and 10% over-detection. The non-detection rate is 34.5% in the conventional vision test and 0% in the Faster R-CNN test. The over-detection rate is 100% in the conventional vision test and 6.9% in Faster R-CNN. From these results, it is confirmed that deep learning technology is very useful for detecting welding error of lead tabs in automobile batteries.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.457-467
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• 2022

Electron bombardment to silicate glass during electron probe microanalysis (EPMA) causes outward migration of Na from the excitation volume and subsequent decrease in the measured X-ray count rates of Na. To acquire precise Na₂O content of silicate glass, one should use proper analytical technique to avoid or minimize Na migration effect or should correct for decreases in the measured Na X-ray counts. In this study, we analyzed 8 silicate glass standard samples using automated Time Dependent Intensity (TDI) correction method of Probe for EPMA software that can calculate zero-time intercept by extrapolating X-ray count changes over analysis time. We evaluated an accuracy of TDI correction for Na measurements of silicate glasses with EPMA at 15 kV acceleration voltage and 20 nA probe current electron beam, which is commonly utilized analytical condition for geological samples. Results show that Na loss can be avoided with 20 ㎛-sized large beam (<0.1 nA/㎛²), thus silicate glasses can be analyzed without TDI correction. When the beam size is smaller than 10 ㎛, Na loss results in large relative errors up to -55% of Na₂O values without correction. By applying TDI corrections, we can acquire Na₂O values close to the reference values with relative errors of ~ ±10%. Use of weighted linear-fit can reduce relative errors down to ±6%. Thus, quantitative analysis of silicate glasses with EPMA is required for TDI correction for alkali elements such as Na and K.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.5
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• pp.211-220
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• 2022

Recently, research on smart factories triggered by the 4th industrial revolution is being actively conducted. Accordingly, the manufacturing industry is conducting various studies to improve productivity and quality based on deep learning technology with robust performance. This paper is a study on the method of detecting tire surface defects in the visual inspection stage of the tire manufacturing process, and introduces a tire surface defect detection method using a depth image acquired through a 3D camera. The tire surface depth image dealt with in this study has the problem of low contrast caused by the shallow depth of the tire surface and the difference in the reference depth value due to the data acquisition environment. And due to the nature of the manufacturing industry, algorithms with performance that can be processed in real time along with detection performance is required. Therefore, in this paper, we studied a method to normalize the depth image through relatively simple methods so that the tire surface defect detection algorithm does not consist of a complex algorithm pipeline. and conducted a comparative experiment between the general normalization method and the normalization method suggested in this paper using YOLO V3, which could satisfy both detection performance and speed. As a result of the experiment, it is confirmed that the normalization method proposed in this paper improved performance by about 7% based on mAP 0.5, and the method proposed in this paper is effective.