• 한국치위생학회지
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• 제12권3호
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• pp.641-646
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• 2012

Objectives : The purpose of this study is to analyze the sterilizing effects of toothbrushes by administering bacteria into toothbrushes and reproducing the antibacterial effects using a microwave oven. Methods : The heads of four-row mid-strength toothbrushes were cut, put in a bacterial solution ($3{\times}10^9cells/ml$) for vortexing, and sterilized with microwaves for 0, 30, and 60 seconds. They were then moved into four tubes containing DW 10 ml and suspended in a vortex mixer for two minutes to separate bacteria from them. DW 9ml was added by 1ml of bacteria for dilution of $10{\sim}10^6$ times. It was then administered to the BHI agar plate by 0.1ml and cultured at $37^{\circ}C$ for 24 hours. Total number of bacteria adhered to a toothbrush was obtained by multiplying the number of colonies by the dilution factor. The experiment was done in the first, second, and third step, being repeated in a normal temperature drier ($23^{\circ}C$) after 5, 9 and 24 hours. Results : The results of the experiment revealed that the sterilizing effects were 95% or over. When toothbrushes were sterilized for 60 seconds, the number of colonies is about 11 after drying for 5 hours, 7 after drying for 9 hours and 2 after drying for 24 hours. The sterilizing effects reached 98% when the bacteria-administered toothbrush was sterilized for 1 minute after drying for 24 hours. Conclusions : The results demonstrated that toothbrush sterilizing by using microwave is a suitable way to prevent cross-contamination of toothbrushes by oral bacterial infection and thus easy to use at home. However, this study suggests that toothbrush sterilizing by using microwave should be limited within two times a week because the physical properties of toothbrush might be changed.

• 한국수소및신에너지학회논문집
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• 제24권2호
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• pp.142-149
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• 2013

Carbon materials are mainly used as catalyst supports for polymer exchange membrane fuel cell (PEMFC). Catalyst supports are required specific characteristics of the carbon materials, such as large surface area and high electrical conductivity. Attempted were to improve electrical conductivity and to maintain high surface area of carbon materials using a microwave treatment. Microwave treatment, as a relatively new technique, takes short reaction time and reduce the consumption of the gases used for carbon treatment compared to a traditional heat treatment. Hybrid carbon (ACF/Graphene) as catalyst supports by microwave-irradiation method for PEMFC increase the cell performance because of increased electrical conductivity resulting in triple-phase contact and reduced the interfacial resistance. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-Ray Diffraction (XRD) were employed to analyze carbon materials. The performance of microwave-treated carbon materials was evaluated by measuring current-voltage (I-V) characteristics and electrode impedance.

• Korean Chemical Engineering Research
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• 제43권6호
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• pp.683-690
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• 2005

왕겨를 마이크로파로 탄화하고 그의 탄화속도를 기존의 열적 탄화에 의한 탄화속도와 비교하였다. 왕겨를 $300{\sim}600^{\circ}C$에서 각각 30분 동안 열적 탄화하고 그의 탄화속도를 분석한 결과 탄화온도가 증가할수록 질량감소 및 탄화도(C/H 몰비)가 현저히 증가했지만 왕겨에 마이크로파를 조사하면 입사전력과 조사시간이 증가해도 탄화가 일어나지 않았다. 그러나 $600^{\circ}C$에서 30분 동안 탄화시켜 C/H 몰비가 3.0 이상인 탄화왕겨 6 wt％를 왕겨에 혼합시키고 마이크로파를 조사한 결과 탄화가 잘 되었고 그의 속도식은 마이크로파 입사전력 및 조사시간에 의존하였으며 열적 탄화와 마찬가지로 Arrhenius 식으로 잘 표현되었다. 이때 마이크로파 탄화로 얻어진 활성화에너지는 열적 탄화에 비하여 크게 낮은 반면에 반응속도상수는 훨씬 컸다. 이는 마이크로파 흡수촉진 매체, 즉 촉매적 개시제(initiator)로 사용된 탄화왕겨에 대한 마이크로파 에너지의 내부 부피가열 특성에 기인한 것으로 판단된다. 마이크로파 흡수특성에 대한 왕겨의 회분과 탄화왕겨의 탄화도 및 혼합비율에 대한 영향을 검토하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권2호
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• pp.68-71
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• 2006

Active thermography has been used for several years in the field of remote non-destructive testing. It provides thermal images for remote detection and imaging of damages. Also, it is based on propagation and reflection of thermal waves which are launched from the surface into the inspected component by absorption of modulated radiation. For energy deposition, it use external heat sources (e.g., halogen lamp or convective heating) or internal heat generation (e.g., microwaves, eddy current, or elastic wave). Among the external heat sources, the ultrasound is generally used for energy deposition because of defect selective heating up. The heat source generating a thermal wave is provided by the defect itself due to the attenuation of amplitude modulated ultrasound. A defect causes locally enhanced losses and consequently selective heating up. Therefore amplitude modulation of the injected ultrasonic wave turns a defect into a thermal wave transmitter whose signal is detected at the surface by thermal infrared camera. This way ultrasound thermography(UT) allows for selective defect detection which enhances the probability of defect detection in the presence of complicated intact structures. In this paper the applicability of UT for fast defect detection is described. Examples are presented showing the detection of defects in PCB material. Measurements are performed on various kinds of typical defects in PCB materials (both Cu metal and non-metal epoxy). The obtained thermal image reveals area of defect in row of thick epoxy material and PCB.

• 공업화학
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• 제18권4호
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• pp.320-325
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• 2007

본 연구에서는 재래식 및 마이크로파 합성법을 통하여 비수계 유기용매인 diethanolamine을 용매로 하여 초산니켈 수용액과 히드라진 수화물로부터 니켈 분말을 합성하였다. X선 회절분석, 주사 전자현미경 분석, 열분석 및 X선 광전자 분광기 분석등을 통하여 마이크로파의 비열적 효과 및 반응 조건이 니켈분말의 합성에 미치는 영향을 조사하였다. 재래식 합성과 비교해보면, 마이크로파를 이용한 합성에서 마이크로파의 비열적 효과에 기인하여 상대적으로 응집이 적게 일어나고, 입자 크기는 작고, 입도 분포는 균일하였다.

• Korean Journal of Acupuncture
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• 제22권2호
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• pp.127-149
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• 2005

This study is designed to investigate the method of manufacturing herbal acupuncture through literature of oriental medicine. The findings of this study are as follows; 1. The methods of manufacturing herbal acupuncture go through the process of abstraction, purification, mixing, filtration, putting and tight sealing in the container, sterilization, quality control, printing and packing 2. There are many ways to manufacturing herbal acupuncture, for example water-alcohol precipitation, alcohol-water precipitation, liquid-liquid abstract, acid-base abstract, metal base precipitation, distillation, molecular structure, polyamide absorption, dialysis, and ion exchange, etc. And popular method is water-alcohol precipitation. This is through alcohol precipitate extracting the principal ingredients from water abstraction. This is very simple and efficient way using melting characteristics of compounds in herb to water and ethanol. 3. Sterilization of herbal acupuncture is through heating-pressure, boiling, steam flowing, low temperature, filtering, radiation, cooling, and microwaves. Nowadays filtering is commonly used. And sterilization is estimated by an examination of asepsis . 4. Herbal acupuncture must be undergo study and experiment to clinical use. The problems of herbal acupuncture are turbidity, instability, causing hemolysis, pain, and fever. So many provisions (addition, sterilization, and filtration etc.) must be prepared. 5. The theory of manufacturing herbal acupuncture is from oriental medicine, not western. So it must be corresponded to oriental medical theory, for example Gimi(氣味), Guigyung(歸經), Ingyung(引經), Bosa(補瀉), and Match of Herb. It is recommended that further study of many other sided investigations in the future.

• 한국재료학회지
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• 제30권9호
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• pp.489-494
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• 2020

SiC is a material with excellent strength, heat resistance, and corrosion resistance. It is generally used as a material for SiC invertors, semiconductor susceptors, edge rings, MOCVD susceptors, and mechanical bearings. Recently, SiC single crystals for LED are expected to be a new market application. In addition, SiC is also used as a heating element applied directly to electrical energy. Research in this study has focused on the manufacture of heating elements that can raise the temperature in a short time by irradiating SiC-I₂ with microwaves with polarization difference, instead of applying electric energy directly to increase the convenience and efficiency. In this experiment, Polydimethylsilane (PDMS) with 1,2 wt% of iodine is synthesized under high temperature and pressure using an autoclave. The synthesized Polycarbosilane (PCS) is heat treated in an argon gas atmosphere after curing process. The experimental results obtain resonance peaks using FT-IR and UV-Visible, and the crystal structure is measured by XRD. Also, the heat-generating characteristics are determined in the frequency band of 2.45 GHz after heat treatment in an air atmosphere furnace.

• 대한화학회지
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• 제50권1호
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• pp.53-59
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• 2006

분자체를 마이크로 파와 일반적인 수열 합성방법을 이용하여 같은 반응물로부터 제조하였으며 합성, 특성 분석 및 산화 반응 촉매로의 가능성을 비교하였다. FAPO-5는 마이크로 파에 의해 비교적 짧은 시간에 합성이 이루어 졌으며 일반 수열 합성에 비해 약 1/20 정도의 시간으로 합성이 가능하였다. 즉, 170oC에서 마이크로파의 경우 15분, 일반적인 수열 합성의 경우 약 6시간 이내에 합성이 완결되었다. 표면적 및 철의 배위 상태 등은 두 시료에서 큰 차이가 없었다. 마이크로파에 의해 얻어진 FAPO-5는 일반 수열 합성에 의해 얻어진 FAPO-5에 비해 에폭시화 반응에서 에폭시드의 수율이 높았으며 이는 상대적으로 큰 소수성 때문인 것으로 생각되었다.

• 천문학회보
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• 제38권1호
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• pp.65.1-65.1
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• 2013

The 2011 August 09 Flare is one of the largest X-ray flares of Sunspot Cycle 24 to attract a lot of attention for its various activities detected in coronal images. In this study we concern ourselves mostly on information of high energy electrons produced during this flare provided by hard X ray data from the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) and radio data from the Korean Solar Radio Burst Locator (KSRBL) and Ondrejov. EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory are used to provide the context of magnetic reconnection. In our results, (1) HXR spectra have a rich spectral morphology. Initially it could be fit by one thermal component (T~30MK) and one single power law nonthermal spectrum, but later a better fit could be made by introducing an additional thermal component (T~55 MK). (2) Time delays between the KSRBL burst and the RHESSI hard X-ray emission were found which are more obvious at low frequencies and insignificant at high frequencies. (3) The HXR source lies in the core of the quadrupolar active region. In our interpretation based on AIA 94 A images, the outer part of the active region erupted to be blown out, leaving the intense hard X-ray emission concentrated in the core. We relate the appearance of the second thermal component to the evolution of the AIA 171 and 94 A images. The time delays of microwave peaks to HXR peaks are interpreted as indicating presence of trapped electrons in larger closed magnetic loops. With these result we conclude that the hard X ray and microwaves are due to impulsive acceleration in the low and high heights and a sigmoidal reconnection scenario.

• 한국식품영양과학회지
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• 제29권1호
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• pp.168-173
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• 2000

The purpose of this study was to investigate the changes of microsomal mixed function oxidase (MFO) and xanthine oxidase activities (XOD) in the liver of rats exposed to microwave. Sprague-Dawley male rats weighing 200$\pm$10g body weight were randomly assigned to a normal and microwave exposed(MW) groups; microwave exposed groups were divided into two groups; microwave (MW) group and green tea(GT) gropu which were fed distilled water and green tea extracts during experimental periods, respectively. Rats were irradiated with microwave at the frequency of 2.45 GHz for 15min and rats wre sacrificed at the 4th day of the microwave irradiaton. The hemoglobin level of GT group was higher than that of the normal gropu and MW group, but the hematocrit value was not significantly different among all experimental gropus. The activity of serum GOT of MW group was significantly increased but that of GT group was similar to normal group. Activities of GPT were not significantly different among all experimental groups. Liver XOD activity was significantly increased in the microwave exposed groups but green tea normalized the XOD activity. The activity of hepatic microsomal cytochrome P450 was significantly increased in MW group compared to normal group and that of GT group was similar to that of the normal group. The activity of hepatic microsomal NADPH-cytochrome P450 reductase was also significantly increased in MW group compared to normal group, but that of GT group was similar to that fo the normal group. In conclusion, the activities of MFO and XOD were elevated by microwave irradiaton, but the activation of MFO system as well as the damage of the liver by microwave were reduced by green tea supplementation.