第10戰鬪飛行團의 操縱士 給食 食品分析

홍동기,장학천 공군본부 의무감실 1964 항공의학 Vol.12 No.2

초음파를 이용한 프로바이오틱스 분말의 유통기한 연장 및 생존율증대 효과

홍동기,정성은,이명희,이호진,이재호,나국남,최일동,이정열,심재헌 한국낙농식품응용생물학회 2018 Journal of Dairy Science and Biotechnology (JMSB) Vol.36 No.4

The purpose of this study was to investigate the effect of ultrasonic treatment during probiotics production process on the shelf life and the survival rate. Once Lactobacillus plantarum and Bifidobacterium longum were cultured in edible culture medium, ultrasonic treatment was performed at 100 Hz for 1, 2, 5, 7, and 10 minutes. Ultrasonic-treated L. plantarum HY7715 and B. longum HY8001 were centrifuged, mixed with a cryoprotectant, and lyophilized. The prepared lactic acid bacteria powder was individually packaged. After 6 months, viable cell counts were measured separately under cold storage and room temperature. In vitro digestion experiments were performed to determine the survival rate at digestive tract. As a result, it was observed that shelf life and survival rate were increased compared to untreated control group.

Synthesis and Preparation of Solid Polymer Electrolytes Based on Anion-Trapping Boron Moieties and Polysiloxane for Lithium Ion Batteries

홍동기,백지훈,김상완,이종찬 한국고분자학회 2020 한국고분자학회 학술대회 연구논문 초록집 Vol.45 No.2

Preparation of Solid Polymer Electrolytes Based on Polysiloxane and Anion-Trapping Boron Moieties for Lithium Ion Batteries

홍동기,백지훈,김상완,이종찬 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

In this study, solid polymer electrolytes were prepared using polysiloxane, which has low glass transition temperature, and anion-trapping boron moieties. Polysiloxane having thiol group was synthesized via sol-gel reaction of 3-mercaptopropyl(dimethoxy)methylsilane. Allyl PEG was synthesized by the reaction between poly(ethylene glycol) methyl ether and allyl bromide. Crosslinker having boron moieties was synthesized by the reaction between poly(ethylene glycol) methacrylate and trimethyl borate. Solid polymer electrolytes were prepared by photo-initiated thiol-ene click reaction between thiol group of polysiloxane and carbon-carbon double bond of allyl PEG and the crosslinker. The thermal and electrochemical properties of the prepared solid polymer electrolytes were investigated.

Synthesis and Characterization of All-Solid-State Polymer Electrolytes Based on Anion-Trapping Boron Moieties and Polysiloxane for Lithium Metal Batteries

홍동기,백지훈,김상완,이종찬 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

In this study, all-solid-state polymer electrolytes were prepared via thiol-ene click reaction between anion-trapping boron moieties and polysiloxane. Boron containing poly (ethylene glycol) (PEG) crosslinker was synthesized by the reaction between trimethyl borate and poly (ethylene glycol) methacrylate. Branched polysiloxane with thiol group was synthesized by acid-catalyzed reaction between (3-mercaptopropyl) dimethoxymethylsilane and (3-mercaptopropyl) trimethyl silane. Allyl PEG was synthesized by reaction between poly (ethylene glycol) methyl ether and allyl bromide using KOH catalyst. The all-solid-state polymer electrolytes were prepared by UV-initiated thiol-ene click reaction between carbon-carbon double bond of allyl PEG and the boron crosslinker and thiol group of polysiloxane. The thermal properties and ionic conductivity of the prepared solid polymer electrolytes were investigated.

Carbon nanodots assisted homogeneous lithium deposition for lithium metal battery

홍동기,박수진 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.1

Preparation of Thermally Stable and Nonflammable Gel Polymer Electrolytes based on Perfluoropolyether for Lithium Batteries

홍동기,백지훈,김동균,이진홍,김상완,이종찬 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

A gel polymer electrolyte (FGPE) based on perfluoropolyether (PFPE) was prepared using PFPE crosslinker via photo-initiated polymerization. The ionic conductivity and Li ion transference number of the prepared electrolyte are 1.72 x 10^-5 S cm^-1 and 0.53 at 60 ℃. The FGPE has high thermal stability, without any weight loss up to 175 ℃, and nonflammability. Moreover, the FGPE shows an excellent electrochemical stability (up to 5.0 V vs. Li/Li⁺). As a result, the FGPE is expected to be suitable electrolyte for safety-enhanced high-temperature lithium batteries.

Solid Polymer Electrolytes Based on Anion-Trapping Moieties and Polysiloxane for Lithium Ion Batteries

홍동기,백지훈,김상완,이종찬 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In this study, solid polymer electrolytes were prepared via in situ polymerization using UV polymerization of polysiloxane and aniontrapping boron moieties. Polysiloxane having thiol group was synthesized by reaction between 3-mercaptopropyl(dimethoxy)methylsilane and 3-mercaptopropyltrimethylsilane. Allyl PEG was synthesized by reaction between poly(ethylene glycol) methyl ether and allyl bromide with KOH catalyst. Boron moieties containing crosslinker was synthesized by the reaction between trimethyl borate and poly(ethylene glycol) methacrylate. Solid polymer electrolytes were prepared by UV-initiated thiol-ene click reaction between thiol group of polysiloxane and carbon-carbon double bond of allyl PEG and the boron crosslinker. The thermal properties and ionic conductivity of the prepared solid polymer electrolytes were investigated.

Customer Acceptance Procedure for Clinac (21EX-Platinum)

홍동기,이우석,권경태,박광호,김정만,Hong, Dong-Ki,Lee, Woo-Seok,Kwon, Kyung-Tae,Park, Kwang-Ho,Kim, Chung-Man 대한방사선치료학회 2004 大韓放射線治療技術學會誌 Vol.16 No.2

목적 : 환자의 치료에 있어서 정확한 장비의 설치와 성능 평가는 치료의 질을 향상시키는데 중요한 요소라고 할 수 있으며 사용자가 장비의 특성과 사용 방법을 숙달하고 업무를 수행하는 것이 매우 중요하다고 생각한다. 그러므로 방사선 치료기를 설치하고 방사선 치료를 하기 전에 사용자가 직접 장비의 설치와 성능 평가에 참여하고 특성을 파악하여 이해하는 것이 필요하다. 본 연구에서는 CAP의 과정과 성능 평가결과를 소개하고자 한다. 대상 및 방법 : 선형가속기 21EX(varian, USA)를 대상으로 설치 시부터 성능 검사까지 전 과정을 평가하였고 성능평가는 크게 radiation survey, mechanical test, radiation isocenter test, beam performance, dosimetry, enhanced dynamic wedge로 구분하여 X-omat film(kodark), 선량 측정 장비(multidata, densitometer, electrometa)를 이용하여 실시하였다. 또한 선형가속기에 부착된 MLC(millenium, 120leaf)와 EPID(portal vision)의 성능 평가는 별도로 실시하였다. 결과 : Survey meter를 이용하여 측정한 leakage는 허용 범위 이하의 선량이 검출되었고 mechanical test에서 collimator, gantey, couch rotation은 1mm 이하였고 육안으로 평가한 angle은 digital이 ${\pm}1^{\circ}$이내에 mechanical은 ${\pm}5^{\circ}$이내였다. 또한 light field와 cross-hair의 직선성 검사도 1mm이내로 평가되었다. (A)symmetrical jaw field는 upper/lower 모두 ${\pm}0.5mm$이내였다. X-omat film을 이용한 radiation isocenter test는 1mm 이하였고 light field와 radiation field 의 일치성 검사는 ${\pm}1mm$ 이내였으며 선량 측정 장비를 이용하여 측정한 $\%DD$는 photon energy는 모두 ${\pm}1\%$ 이내로 electron energy는 $90\%,\;80\%,\;50\%,\;30\%$를 측정한 결과 허용 범위 내에서 평가되었다. photon 과 electron energy의 flateness는 각각 $2.3\%$(기준 $3\%$)이내, $3\%$(기준 $4.5\%$)이내이고 symmetry는 $0.45\%$(기준 $2\%$), $0.3\%$(기준 $2\%$)이내에서 평가 할 수 있었다. 그리고 dosimetry test는 sort term, MU setting, rep rate, dose rate accuracy를 photon과 electron energy 별로 MU와 gantry angle을 바꿔가면서 측정한 결과 허용범위 오차이내에 포함되는 것을 확인 할 수 있었다. EPID(portal vision)의 Exact-Arm의 기계적인 검사는 vertical, lateral, longitudinal은 허용범위 내에서 동작했으며 명암과 해상도 검사도 05.mm의 니크롬선이 선명하게 나타났으며 phantom의 음영도 뚜렷하게 나타났다. Multileaf collimator(MLC)검사는 leaf이 isocenter의 중심에 정확하게 배열되었으며 재현성 검사도 정상적으로 동작하였다. 결론 : Clinac 21EX 장치의 customer acceptance를 통해서 향후의 환자의 치료를 하는데 있어 장치의 안정성을 확인 할 수 있었으며 치료 전의 선형가속기와 주변장치의 특성을 파악 할 수 있어서 장비 사용에 있어서 어려움을 감소시킬 수 있으리라고 생각된다. 또한 사용자가 적극적으로 참여함으로써 앞으로 환자를 치료하는데 있어서도 많은 도움이 되리라 생각한다. Purpose : For qualify improvement in radiotherapy, it is important to set up and evaluate equipment (linac) accurately. In addition, technicians are needed to be fully aware of the equipment's detailed quality and its manual. Therefore, the result of ATP is evaluated and introduced, in order that the technicians are skilled by participating in quality assurance (QA) and understanding the quality of the equipment before clinical use. Method and Material : QA for LINAC 21EX (Varian, US) was done with suppliers its procedure was divided into radiation survey, mechanical test, radiation isocenter test, bean performance, dosimetry, and enhanced dynamic wedge and using X-omat film (Kodak), multidata, densitometer, and electrometer. QA of MLC (Millennium, 120 leaf) attached to LINAC and EPID (Portal vision) were done separately. Result : The leakage dose by survey meter was below the tolerance. In mechanical test, collimater, gantry, and couch rotation were less than 1mm, and the angles were ${\pm}0.1^{\circ}$ for digital and ${\pm}0.5^{\circ}$ for mechanical. The alignment test of the light field and crosshair were evaluated less than 1mm. The (a)symmetrical jaw field was less than ${\pm}0.5mm$. The radiation isocenter test using X-mat film was less than 1mm. The consistency of light field and radiation field was less than ${\pm}0.1mm$. PDD for photon energy was less than ${\pm}1\%$ and for electron energy of $90\%,\;80\%,\;50\%,\;and\;30\%$ were evaluated within the tolerance. Flatness for photon and electron energy was evaluated $2.3\%$ (tolerance $3\%$) and $3\%$ (tolerance $4.5\%$), respectively, and symmetry was $0.45\%$ (tolerance $2\%$) and $0.3\%$ (tolerance $2\%$), respectively. Dosimetry test for short term, MU setting, rep rate, and dose rate accuracy of photon and electron energy was within the tolerance depending on energy, MU, and gantry angle. Conclusion : Accuracy and safety for clinical use of Clinac 21EX was verified through customer acceptance procedure and the quality of the equipment was found out. These can reduce the difficulties in using the equipment. Furthermore, it is useful for clinically treatment of patients by technicians' active participations.

두경부암 환자 치료시 3차원 보상체의 임상 적용에 대한 고찰

홍동기,이정우,이두현,박광호,김정만,Hong, Dong-Ki,Lee, Jeong-Woo,Lee, Koo-Hyun,Park, Kwang-Ho,Kim, Jeong-Man 대한방사선치료학회 1997 大韓放射線治療技術學會誌 Vol.9 No.1

The goal of radiation treatment planning is to deliver the dose to the patient within $5\%$ of that prescribed. We have often encountered the situation that the area which have not only several irregular contours but also tissue heterogeneities should be treated. With conventional devices such as wedges, missing tissue compensator. there are some limitations to achieve the uniform dose distribution in treatment volume. The use of CT simulator, 3-D planning system, computer-controlled milling machine enables it to deliver the dose uniformally. This report includes the whole procedure which have patient data acquisition 3D planning, computer-controlled milling, performance verification of 3D compensator, and TLD evaluation. We applied it for the treatment of head and heck cancer only. In Spite of the irregular contour and different electron density of tessue, we have achieved the uniformity of the dose distribution within ${\pm}3\%$ relatively. Although there are some problems which are not only verification of performance but uncertainties of using the new treatment device, we believe that the improvement of dosimetry will eliminate the uncertainties of that application. so the other lesions besides head and neck can will be ale to use the 3D compensator to achieve the dose uniformity