• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.165.1-165.1
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• 2016

표면활성화 접합은 이종 소재의 표면을 제어하여 직접 접합하는 기술이다. 본 연구에서는 표면활성화 접합을 이용하여 고 방열특성의 LED용 히트스프레더(heat spreader)를 제작하기 위하여 $Al-Al_2O_3$ 복합소재를 제조하였다. LED 제품의 히트스프레더는 LED에서 발생하는 열을 한 곳으로 집중하는 것을 막아 열을 분산하는 금속판을 의미한다. 최근의 LED 제품은 고출력화에 의한 발열량의 급증으로 MCL(Metal Clad Laminate)를 이용하여 LED 칩에서 발생된 열을 외부로 배출하는 모듈구조를 나타내는 경우가 대다수이다. LED에서 열이 증가하게 되면 LED의 효율이 감소하고, 수명이 줄어드는 현상을 보이기 때문에 방열특성은 매우 중요하다. 따라서 고출력화되어 LED 칩에서 발생되는 열을 제어하는 기술이 이슈화 되고 있다. 기존의 히트스프레더 구조는 통상적으로 Al/절연층(폴리머)/Al으로 폴리머의 열전도율이 1W/mk로 고출력화에 의해 급증하는 LED의 발열량을 충분히 해소시키기 어렵다. 본 연구에서는 급증하는 LED의 방열량을 해소시키기 위해서 기존의 Al/폴리머/Al의 구조를 $Al/Al_2O_3/Al$의 구조로 개발하기 위해서 HV-SCDB 기술을 이용한 $Al-Al_2O_3$ 복합소재 제조 및 접합특성에 관하여 연구하였다.

• Membrane Journal
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• v.14 no.2
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• pp.142-148
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• 2004

This paper presents the enhancement of oxygen transfer efficiency using vibrating intravascular lung assist device (VIVLAD) for patients having chronic respiratory problems. The flow rate was controlled by the pump and monitored by a built-in flow meter. The vibration apparatus was composed of a piezo-actuator, a function generator, and a power amplifier. Gas flow rates of up to 6 L/min through the 120-cm-long hollow fibers have been achieved by exciting a piezo-actuator. The output PVDF sensor and FRF (frequency response function) were investigated by various frequency in VIVLAD. As a result, the maximum oxygen transfer rate was found to occur with maximum amplitude and the transfer of vibration to the hollow fiber membranes. It was excited by the frequency band of 35 Hz at various distilled water flow rates, and various module types.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.787-790
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• 2012

Recently due to the development of the information society and the spread of computer, interest for personal information is increased and as policy and technology associated with the development, we have been various attempts to protect your personal information. In this paper, for agencies and departments to computer use and to deal with Important data of individuals, personal information or the company's confidential information, we proposed modules to protect them. As a result, we prevent a public agency or private institutions within that using mean bad or stealing another person's information. When we communicate various information with the systems in the institutions, the module can be prevented critical data and personal information exposure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.945-954
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• 2004

Recently, specifications of flat display module is going to be higher definition, brightness and more wide viewing angle. On the other hand, physical thickness of those modules is forced to be slimmer and lighter. The flat display modules such as plasma or TFT-LCD employ thin crystallized panels that are normally weak to high level transient mechanical energy inputs. As a result, anti-shock performance is one of the most important design specifications of TFT-LCD modules. TFT-LCD module manufacturers and their customers like PC or TV makers perform a series of strict impact/drop test for the modules. However most of the large display module designs are generated based on engineer's own trial-error experiences. Those designs may result in disqualification from the drop/impact test during final product evaluation. A rigorous study on the impact failure of the displays is of course necessitated in order to avoid the problems. In this article, a systematic design evaluation is presented with combinations of FEM modeling and testing to support the optimal shock proof display design procedure.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.231-231
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• 2012

7개 나라가 참여해서 공동으로 제작하고 있는 국제핵융합실험로(ITER)는 2020년경에 제작 설치가 완료될 예정이다. ITER 장치에는 6개의 시험 블랑켓 모듈(Test Blanket Module : TBM)이 장착될 예정이며, 그 중에서 한국도 1개를 독자적으로 제작해서 설치할 예정이다. 한국형 헬륨 냉각 고체형 증식(Helium Cooled Solid Breeder : HCSB) TBM이며, 한국은 ITER 참여국 중 유일하게 중성자 반사 재료를 채택한 것이 특징이다. 중성자 반사재료로는 지름 1 mm 내외의 흑연 페블에 SiC를 코팅해서 사용할 예정이다. SiC는 고온저방사화 물질로 차세대 핵융합로의 구조 재료로도 개발되고 있는 물질로, 이렇게 하면 흑연의 단점인 기계적 특성 향상뿐만 아니라, 산화나 화재 등에 대한 사고의 부담도 크게 줄일 수 있는 장점이 있다. 흑연위에 SiC를 코팅하는 방법은 여러 가지가 있으며, 그 중에서 비교적 간단한 건식 방법은 RF Sputtering, PECVD 등이 있다. 건식은 코팅방법이 간단하고 비교적 쉬운 편이지만 페블표면에 양질의 SiC 박막을 얻기가 쉽지 않은 단점이 있다. 이들 방법보다 습식법은 코팅이 까다롭지만 양질의 코팅막을 비교적 쉽게 얻을 수 있는 장점이 있다. CVD의 경우 전구체 물질로 여러 가지 물질이 사용될 수 있으며 대표적으로 $SiH_4$, $Si(CH_3)_4$, $CH_3SiCl_3$ 등이 있으며, 캐리어 가스로는 $H_2$가 사용된다. 이렇게 얻어진 SiC 코팅페블은 흑연에 비해 파괴강도도 향상되고 마모 등에 강한 것을 확인할 수 있었다.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.553-559
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• 2016

There has been increasing global interest in the environmental pollution problems produced by fossil fuel consumption and greenhouse gas emissions. In order to tackle these issues, new renewable energy such as solar, wind, bio gas, fuel cell and pressure retarded osmosis(PRO) have been developed extensively. Among these energy sources, PRO is one of the salinity gradient power generation methods. In PRO, energy is obtained by the osmotic pressure generated from the concentration difference between high and low concentration solutions separated by a semipermeable membrane. The development for high power density PRO membranes is imperative with the purpose of commercialization. This study investigates development of thin film composite PRO membrane and spiral wound module for high power density. Also, the influence of membrane backing layer on power density was identified, and the characteristic factors of PRO membranes was determined. Different backing layers were used to improve power density. As expected, the PRO membrane with more porous backing layer showed higher power density.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.209-216
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• 1998

Nanofiltration[NF45] and reverse osmosis membrane(HR98PP) separation treatment of dyestuff wastewater was carried out In order to separate relatively pure water from synthetic dyestuff wastewater, which consists of reactive dye, acid dye, basic dye, direct dye, and disperse dye. The experiments were performed by using the plate and frame membrane module. In the nanofiltration and reverse osmosis membrane separation, When the NaCl concentration was 0.1, 5.0, and 20.091, retention was 63.0, 46.0, 0.9%, respectively. When permeate flux was 125.0, 67.5, and 45.0 L/$m^2$ h, the osmotic pressure increased with Increasing the NaCl concentration. Permeate flux of two membranes Increased as temperature Increased due to segmental movement of polymer of the membrane and the rejection rate of dyestuff was decreased gradually. It was found that the rejection rate was about 95% in the nanofiltratlon, while the reverse osmosis membrane showed a high rejection rate of 99% under all temperature and pressures conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.76-83
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• 2014

During PEMFC(Proton Exchange Membrane Fuel Cell) operation monitoring and diagnosis are important issues for reliability and durability. Stack defect can be followed by a critical cell voltage drop in the stack. One method for monitoring the cell voltage is CVM(Cell Voltage Monitoring), where all cells in the stack are electrically connected to a voltage measuring system and monitored these voltages. The other methods are based on the EIS(Electrochemical Impedance Spectroscopy) and on nonlinear frequency response. In this paper, intermodulation(IM) method for diagnosis PEMFC stack is introduced. To detect one or more critical PEMFC cell voltage PEMFC stack is excited by two or more test sinusoid current, and the frequency response of the stack voltage is analyzed. If one or more critical cell voltage exists, higher harmonics on the voltage frequency spectrum will appear. For the proposed IM method, stack simulation and experiments are conducted.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.1103-1113
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• 2012

DLP technology has been effectively enforcing privacy protection policy in on-line computing environment. However, with wide spread use of smart devices and promotion of smart-works, it has been pointed out that DLP technology cannot effectively prevent privacy leakage at smart devices and is comparatively weak at APT attack. In this paper, we suggests a hybrid approach, PPS, which integrates E-DRM system with DLP technology, taking advantages of both technologies. The technology basically uses encryption function and access control of E-DRM system, and thus it can effectively prevent leakage of privacy information of customers, even if the documents are in the hands of malicious third parties.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.178-180
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• 2021

In this paper, we design a system to monitor environmental data in fish farms in real-time and provide machine learning-based prediction services to prevent damage on fish farms caused by changes in the sea environment. The proposed system will install an IoT device module consisting of sensors that can measure hydrogen concentration, salinity, dissolved oxygen, and water temperature, which can be transferred to Cloud DB using LTE or LoRa communication technology and then monitor the real-time condition through a web or mobile application. In addition, it has a function to prepare for changes within the environment of fish farms by applying machine learning-based prediction technology using collected data.