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측벽 및 홀 구조를 포함하는 바이오 부품의 플라스틱 사출성형 기술 개발
Trieu Khoa Nguyen,차경제(Kyoung Je Cha),이봉기(Bong-Kee Lee) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
In the present study, a plastic injection molding technology was investigated for a mass-replication of the biomedical product with complicated features. The current plastic biomedical product, which is one part of the novel biomedical device, was designed to have a cylindrical sidewall and rectangular hole. Because the complicated features like sidewall and hole can lead to the critical defects, such as weldline formation, air trap, short shot, and breakage, during the injection molding process, both the precise design of the injection mold and optimization of the processing parameters are required. In this regard, the injection mold to produce the biomedical product with sidewall and hole structures was designed and manufactured. The experimental and numerical investigations of the injection molding filling stage were carried out. From the investigations, the detailed filling sequence and flow behavior were identified, thereby verifying the feasibility of the current mold design.
고속 솔레노이드 밸브 제어 나노리터급 액적 분주를 통한 액체혼합방법
박성제(Sung Jea Park),차경제(Kyoung Je Cha),권태헌(Tai Hun Kwon) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
In this study, an active mixing method is proposed utilizing a nanoliter-level dispensing system which is controlled by high speed solenoid valves. In the nanoliter-level dispensing system, pressurized air transfers liquids from a reservoir to nozzles through tube via high speed solenoid valves, thus injecting liquid droplets into a well. The droplet volume depends on the air pressure, nozzle size and more importantly on the opening time of solenoid valves, which is controlled by a circuit with the help of computer through serial port. Finally a new mixing method is to inject two or more different liquids through different slanted nozzles, simultaneously or alternatingly into a well making use of the so-developed dispensing system. This study also reports successful mixing performance by this new mixing method.
실시간 헬스케어 모니터링의 독립 구동을 위한 접촉대전 발전과 전자기 발전 원리의 융합
조수민 ( Sumin Cho ),정윤수 ( Yoonsu Joung ),김현수 ( Hyeonsu Kim ),박민석 ( Minseok Park ),이동한 ( Donghan Lee ),감동익 ( Dongik Kam ),장순민 ( Sunmin Jang ),라윤상 ( Yoonsang Ra ),차경제 ( Kyoung Je Cha ),김형우 ( Hyung Woo Kim 한국화학공학회 2022 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.60 No.1
Recently, the bio-healthcare market is enlarging worldwide due to various reasons such as the COVID-19 pandemic. Among them, biometric measurement and analysis technology are expected to bring about future technological innovation and socio-economic ripple effect. Existing systems require a large-capacity battery to drive signal processing, wireless transmission part, and an operating system in the process. However, due to the limitation of the battery capacity, it causes a spatio-temporal limitation on the use of the device. This limitation can act as a cause for the disconnection of data required for the user's health care monitoring, so it is one of the major obstacles of the health care device. In this study, we report the concept of a standalone healthcare monitoring module, which is based on both triboelectric effects and electromagnetic effects, by converting biomechanical energy into suitable electric energy. The proposed system can be operated independently without an external power source. In particular, the wireless foot pressure measurement monitoring system, which is rationally designed triboelectric sensor (TES), can recognize the user’s walking habits through foot pressure measurement. By applying the triboelectric effects to the contact-separation behavior that occurs during walking, an effective foot pressure sensor was made, the performance of the sensor was verified through an electrical output signal according to the pressure, and its dynamic behavior is measured through a signal processing circuit using a capacitor. In addition, the biomechanical energy dissipated during walking is harvested as electrical energy by using the electromagnetic induction effect to be used as a power source for wireless transmission and signal processing. Therefore, the proposed system has a great potential to reduce the inconvenience of charging caused by limited battery capacity and to overcome the problem of data disconnection.
정전발전 기반 바람에너지 수확장치의 최적화 및 고전압 생성을 위한 활용 방안
장순민 ( Sunmin Jang ),라윤상 ( Yoonsang Ra ),조수민 ( Sumin Cho ),감동익 ( Dongik Kam ),신동진 ( Dongjin Shin ),이희규 ( Heegyu Lee ),최부희 ( Buhee Choi ),이세혁 ( Sae Hyuk Lee ),차경제 ( Kyoung Je Cha ),서경덕 ( Kyoung Duck Seo 한국화학공학회 2022 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.60 No.2
As the scope of use of portable and wearable electronic devices is expanding, the limitations of heavy and bulky solid-state batteries are being revealed. Given that, it is urgent to develop a small energy harvesting device that can partially share the role of a battery and the utilization of energy sources that are thrown away in daily life is becoming more important. Contact electrification, which generates electricity based on the coupling of the triboelectric effect and electrical induction when the two material surfaces are in contact and separated, can effectively harvest the physical and mechanical energy sources existing in the surrounding environment without going through a complicated intermediate process. Recently, the interest in the harvest and utilization of wind energy is growing since the wind is an infinitely ecofriendly energy source among the various environmental energy sources that exist in human surroundings. In this study, the optimization of the energy harvesting device for the effective harvest of wind energy based on the contact electrification was analyzed and then, the utilization strategy to maximize the utilization of the generated electricity was investigated. Natural wind based Fluttering TENG (NF-TENG) using fluttering film was developed, and design optimization was conducted. Moreover, the safe high voltage generation system was developed and a plan for application in the field requiring high voltage was proposed by highlighting the unique characteristics of TENG that generates low current and high voltage. In this respect, the result of this study demonstrates that a portable energy harvesting device based on the contact electrification shows great potential as a strategy to harvest wind energy thrown away in daily life and use it widely in fields requiring high voltage.
마찰대전 나노발전기의 출력 및 안정성 향상을 위한 일렉트렛 개발
감동익 ( Dongik Kam ),장순민 ( Sunmin Jang ),윤영철 ( Yeongcheol Yun ),배홍은 ( Hongeun Bae ),이영진 ( Youngjin Lee ),라윤상 ( Yoonsang Ra ),조수민 ( Sumin Cho ),서경덕 ( Kyoung Duck Seo ),차경제 ( Kyoung Je Cha ),최동휘 ( Dongwhi 한국화학공학회 2022 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.60 No.1
With the rapid development of ultra-small and wearable device technology, continuous electricity supply without spatiotemporal limitations for driving electronic devices is required. Accordingly, Triboelectric nanogenerator (TENG), which utilizes static electricity generated by the contact and separation of two different materials, is being used as a means of effectively harvesting various types of energy dispersed without complex processes and designs due to its simple principle. However, to apply the TENG to real life, it is necessary to increase the electrical output. In addition, stable generation of electrical output, as well as increase in electrical output, is a task to be solved for the commercialization of TENG. In this study, we proposed a method to not only improve the output of TENG but also to stably represent the improved output. This was solved by using the contact layer, which is one of the components of TENG, as an electret for improved output and stability. The utilized electret was manufactured by sequentially performing corona charging-thermal annealing-corona charging on the Fluorinated ethylene propylene (FEP) film. Electric charges artificially injected due to corona charging enter a deep trap through the thermal annealing, so an electret that minimizes charge escape was fabricated and used in TENG. The output performance of the manufactured electret was verified by measuring the voltage output of the TENG in vertical contact separation mode, and the electret treated to the corona charging showed an output voltage 12 times higher than that of the pristine FEP film. The time and humidity stability of the electret was confirmed by measuring the output voltage of the TENG after exposing the electret to a general external environment and extreme humidity environment. In addition, it was shown that it can be applied to real-life by operating the LED by applying an electret to the clap-TENG with the motif of clap.
곡선형 형상적응형 냉각채널을 갖는 금형 코어 제작을 위한 DMT 공정개발
한지수(Ji Su Han),유만준(Man Jun Yu),이민규(Min Gyu Lee),이윤선(Yoon Sun Lee),김우성(Woo-Sung Kim),이호진(Ho Jin Lee),김다혜(Da Hye Kim),성지현(Ji Hyun Sung),차경제(Kyoung Je Cha) 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.11
The cooling rate and the uniformity of mold temperature, in the injection molding process, possess great influences on the productivity and quality of replications. The conformal cooling channel, which is of a uniform spacing from the mold cavity by the metal additive manufacturing process, receives much attention recently. The purpose of this study is to develop a mold core with a curved conformal cooling channel for a pottery-shaped thick-wall cosmetic container through the hybrid method of direct metal tooling (DMT) process. In this study, we design a mold core that contains the curved cooling channel for the container. A method that divides the cavity is proposed and the DMT process is carried out to form the curved cooling channel. The test mold core, with the curved conformal cooling channel, has been fabricated by the proposed method to confirm the feasibility of the design concept. We show that no leakage is observed for the additive manufactured test mold core, and its physical properties demonstrate that it can be sufficiently used as the injection mold core.