로이유리의 전도성 금속박막을 이용한 발열유리 제작에 관한 연구

오재곤(Chaegon Oh) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.1

본 논문은 로이유리(Low emissivity glass) 표면에 증착되어 있는 금속박막의 전도 특성을 이용하여 발열유리(Heatable glass)를 제작하는 방법에 대해 제안한다. 로이유리의 발열량은 로이유리 표면저항에 의한 주울(Joule) 열에 의존하므로 소재의 표면저항을 측정함으로써 예측 및 설계가 가능하다. 본 연구에서는 저방사층이 11nm인 소프트로이유리 시료에 각 50mm 간격으로 은(Ag) 전극을 형성시키고, 4단자법으로 면저항을 측정하여 로이유리의 소비전력과 발열량을 예측한 후에, 제작 및 실험을 통해 발열성능을 확인하였다. 기존의 발열유리 제작방법은 크게 두 가지로 일반유리(Normal glass)에 니크롬(Nichrome) 열선을 삽입하는 방법과, 일반유리에 전도성 투명박막을 증착하는 방법이 있다. 니크롬 열선 삽입 방식은 발열성능은 우수하나 유리 고유의 투명성을 저해하고, 전도성 투명박막을 증착하는 방법은 투명성은 양호하나 공정이 복잡하여 실용성이 저하된다. 본 논문에서는 주로 건축물의 단열효과 향상을 위해 사용되는 로이유리를 이용하여 로이유리 전면에 코팅되어 있는 전도성 금속박막에 레이저 빔을 조사하여 원하는 발열성능을 가지는 발열유리를 제작하는 방법을 제안한다. 제안된 방법은 기존의 니크롬 열선을 삽입하는 방법에 비해 투명성이 양호하고, 전도성 투명박막을 증착하는 방법에 비해 제작과정이 보다 수월함을 확인하였다. 아울러, 레이저를 조사하여 로이유리의 표면 박막을 패터닝(Patterning) 하는 형태에 따른 발열특성의 비교와 로이유리에 적합한 레이저 출력조건을 제시하고자 한다. This paper proposes a method for fabricating heatable glass using the conduction characteristics of metal thin films deposited on the surface of Low-e(Low emissivity) glass. The heating value of Low-e glass depends on the Joule heat caused by Low-e glass sheet resistance. Hence, its prediction and design are possible by measuring the sheet resistance of the material. In this study, silver electrodes were placed at 50 mm intervals on a soft Low-e glass sample with a low emissivity layer of 11 nm. This study measured the sheet resistance using a 4-point probe, predicted the power consumption and heating value of the Low-e glass, and confirmed the heating performance through fabrication and experience. There are two conventional methods for manufacturing heatable glass. One is a method of inserting nichrome heating wire into normal glass, and the other is a method of depositing a conductive transparent thin film on normal glass. The method of inserting nichrome heating wire is excellent in terms of the heating performance, but it damages the transparency of the glass. The method for depositing a conductive transparent thin film is good in terms of transparency, but its practicality is low because of its complicated process. This paper proposes a method for manufacturing heatable glass with the desired heating performance using Low-e glass, which is used mainly to improve the insulation performance of a building. That is by emitting a laser beam to the conductive metal film coated on the entire surface of the Low-e glass. The proposed method is superior in terms of transparency to the conventional method of inserting nichrome heating wire, and the manufacturing process is simpler than the method of depositing a conductive transparent thin film. In addition, the heat characteristics were compared according to the patterning of the surface thin film of the Low-e glass by an emitting laser and the laser output conditions suitable for Low-e glass.

Prevalence and Mechanisms of Low Level Quinolone Resistance among Non-Typhoidal Salmonella Isolates from Human and poultry/Livestock in Korea: Usefulness of Nalidixic Acid Resistance Test

황인숙,송준영,김우주,정혜원,김무상,정희진 대한감염학회 2010 Infection and Chemotherapy Vol.42 No.4

Background: Non-typhoidal Salmonella (NTS) are important commensal microorganisms. We intended to investigate the prevalence and mechanisms of nalidixic acid resistance among NTS isolated from human and poultry/livestock. Methods: A total of 151 Salmonella isolates (36 human and 115 livestock isolates,respectively) was tested for the Minimum inhibitory concentrations (MICs) of nalidixic acid, together with serotyping. As for the nalidixic acid resistant isolates,further studies were taken: MICs of ciprofloxacin, mutation analysis of gyrA and parC genes, and organic solvent tolerance test. Results: Eighty-four isolates of 151 human and livestock isolates were resistant to nalidixic acid. The prevalence of nalidixic acid resistance and was 13.9% (5of 36 isolates) in human isolates and 68.7% (79 of 151 isolates), in the livestock isolates respectively. Among 84 nalidixic acid-resistant isolates, the The prevalence of ciprofloxacin resistance in livestock isolates was 24.1% (1 resistant and 18intermediate of 79 strains), but no ciprofloxacin resistance was found in 5 human isolates. Among 65 nalidixic acid resistant, ciprofloxacin-susceptible isolates, 3(60%, of 5 human isolates) and 60 (100%, all livestock isolates) showed low level fluoroquinolone resistance (ciprofloxacin MIC, 0.125-1.0 μg/μL). Six types of point mutations were found in the analysis of DNA sequencing of the gyrA gene in the 84isolates; 75 isolates showed point mutations on amino acid Ser 83 and/or Asp 87. On the other hand, no point mutation was found from the parC genes. Forty-seven nalidixic acid resistant isolates showed tolerance to organic solvents. Conclusions: Nalidixic acid resistance was a good marker of low level fluoroquinolone resistance. As for the severe NTS infection, MIC test for nalidixic acid would be required.

고효율, 저가화 실리콘태양전지를 위한 Ni/Cu/Ag 금속전극의 특성 연구

이지훈(Ji-Hun Lee),조경연(Kyeng-yeon Cho),이수홍(Soo-hong Lee) 한국태양에너지학회 2009 한국태양에너지학회 학술대회논문집 Vol.- No.-

Crystlline silicon solar cells markets are increasing at rapid pace. now, crystlline silicon solar cells markets screen-printing solar cell is occupying. screen-printing solar cells manufacturing process are very quick, there is a strong point which is a low cost. but silicon and metal contact, uses Ag & Al pates. because of, high contact resistance, high series resistance and sintering inside process the electric conductivity decreases with 1/3. and In pastes ingredients uses Ag where 80∼90% is metal of high cost. because of low cost solar cells descriptions is difficult. therefore BCSC(Buried Contact Solar Cell) is developed. and uses light-induced plating, ln-line galvanization developed equipments. Ni/Cu matel contact solar cells researches. in Germany Fraunhofer ISE. In order to manufacture high-efficency solar cells, metal selections are important. metal materials get in metal resistance does small, to be electric conductivity does highly. efficiency must raise an increase with rise of the curve factor where the contact resistance of the silicon substrate and is caused by few with decrement of series resistance. Ni metal materials the price is cheap, Ti comes similar resistance. Cu and Ag has the electric conductivity which is similar. and Cu price is cheap. In this paper, Ni/Cu/Ag metal contact cell with screen printing manufactured, silicon metal contact comparison and analysis.

Review Article : Low Salt Diet and Insulin Resistance

( Hyunwoo Oh ),( Hyo Young Lee ),( Dae Won Jun ),( Seung Min Lee ) 한국임상영양학회 2016 Clinical Nutrition Research Vol.5 No.1

It is well known that high sodium intake is closely associated with the risk of cardiovascular disease, but the effect of low sodium intake on insulin resistance is not clear. In this article, we summarize findings from previous studies focusing on the association between low sodium intake and insulin resistance. While many investigations on this topic have been conducted actively, their major findings are inconsistent, partly due to different study designs. Thus, additional randomized controlled trials with an adequate study period and reasonable levels of low sodium intake are needed.

해안매립지 하수처리시설물에 적용한 저발열시멘트 콘크리트의 내화학성 평가

정용택,이병재,김윤용 한국구조물진단유지관리공학회 2019 한국구조물진단유지관리공학회 논문집 Vol.23 No.7

Concrete structures built on reclaimed land are combined with chemical erosion such as chlorine and sulfate ions from seawater. Chloride attack deteriorates the performance of the structure by corroding reinforcing bars. In addition, the waste water treatment structure has a problem that the concrete is deteriorated by the sulfate generated inside. Therefore, in this study, the characteristics and chemical resistance of low heat cement concrete used in wastewater treatment structures constructed on reclaimed land were evaluated. As a result of the experiment, the target slump and air content were satisfied under all the mixing conditions. The slump of low heat cement (LHC) concrete was higher than that of ordinary portland cement (OPC) concrete, while the air content of LHC concrete was smaller than that of OPC concrete with the same mix proportion. As a result of compressive strength test, OPC concrete showed higher strength at younger age compared to 28 days. In contrast, LHC concrete exhibited higher strength than OPC concrete at the age of 56 days. As a result of chlorine ion penetration tests, LHC-B concrete showed chlorine ion penetration resistance performance of the “very low” level at the age of 56 days. As a result of chemical resistance evaluation, when the LHC concrete is applied without epoxy treatment, chemical resistance is improved by about 18% compared to OPC concrete. In testing chemical resistance, the epoxy coated concrete exhibited less than 5% strength reduction when compared to sound concrete. 해안매립지에 건설되는 구조물은 해수로부터 유입되는 염소 및 황산염 이온 등의 화학적 침식에 의한 영향을 복합적으로 받는다. 염해는 콘크리트 내부의 철근을 부식시켜 구조물의 성능을 저하시킨다. 또한, 하수처리시설에서는 내부에서 발생되는 황산염에 의해 콘크리트가 열화되는 문제점을 가진다. 따라서 본 연구에서는 해안매립지에 건설되는 하수처리구조물에 적용할 수 있는 혼합형 저발열시멘트의 특성 및 내화학성을 평가하였다. 실험결과, 모든 배합조건에서 목표슬럼프 및 공기량을 모두 만족하였다. 동일 배합조건에서 LHC사용시 OPC보다 슬럼프는 증가되고, 공기량은 감소하는 경향을 나타내었다. 압축강도 시험결과, 초기재령에서는 OPC의 강도발현이 빨랐으며, 28일 이후 LHC가 OPC보다 높은 강도를 나타내었다. 염소이온침투저항성 평가결과, LHC-B의 경우 56일 재령에서, “매우낮음” 단계의 염소이온침투저항성을 나타내 LHC의 내염해성을 확인하였다. 내화학성 평가 결과, 에폭시 처리 하지 않은 경우 LHC를 적용한 경우, OPC보다 약 18%정도 내화학성이 개선되는 것으로 나타났으며, 콘크리트 표면에 에폭시 공법 적용시 강도보존율이 95% 이상 확보 가능한 것으로 확인되었다.

지역필터를 이용한 수변전실 접지저항의 새로운 측정방법

이복희,엄주홍,이승칠,김성원,안창환,Lee, Bok-Hui,Eom, Ju-Hong,Lee, Seung-Chil,Kim, Seong-Won,An, Chang-Hwan 대한전기학회 2001 전기학회논문지C Vol.51 No.3

This paper describes an advanced measuring method and precise evaluation of the ground resistance for the grounding system of energized substations and power equipments. A grounding system of substations consists of all interconnected grounding connections of grounded conductors, neutral ground wires, underground conductors of distribution lines, cable shields, grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding system of high voltage energized substations because of harmonic components caused by switched power supplies or overloads. The conventional fall-of-potential method may be subject to big error if stray ground currents and potentials are present. In this work, to improve the precision in measurements of the ground resistance by eliminating the effects of harmonic components and stray currents and potentials, the investigations of the ground resistance measurement by using a low pass filter in a model energized grounding system were conducted. The accuracy of ground resistance mesurements was evaluated as a function of the ratio of the test signal to noise (S/N). The errors due to the proposed ground resistance measurement method were decreased with increasing S/N and were less than 5[%] as S/N is 10. The proposed ground resistance measurement method appears to be considerably more accurate than the conventional fall-of -potential method. It is allows cancellation of the parasitic resistance of energized grounding systems, to employ the measurement method that allows cancellation of the parasitic effects due to other circulating ground currents and ground potential rises in practical situations.

저방사 필름 적용 공기층을 가지는 FSFB의 하중비에 따른 내화성능 평가

강성묵,김진국 한국콘크리트학회 2023 콘크리트학회논문집 Vol.35 No.5

An analytical investigation was conducted into the fire resistance performance of fabricated slim floor beams (FSFBs) according to the load ratio. The goal was to establish a numerical standard for assessing FSFB members’ performance when exposed to fire during structural calculations or design. Unlike other types of slim floor beams, FSFBs have superior fire resistance due to the presence of an air layer in their manufacturing process. In addition, the application of Low-E film reduces heat transfer in this air layer, thereby improving FSFBs’ fire resistance performance. To address these factors, a finite element model was employed, and variable analysis was conducted. This model’s validity was established by comparing its results with tests and analyses from other research papers. Subsequently, the analysis was performed with the load ratio and the application of Low-E film as variables, using a verification model to ensure its accuracy. Based on the analysis results, the fire resistance performance of FSFBs was compared under various conditions, leading to the derivation of a fire resistance performance regression equation for fire resistance performance, with the load ratio as the independent variable. This regression equation enables the calculation of the load ratio for each FSFB size and usage scenario, depending on whether or not Low-E film is applied.

혈류제한 저강도 근력 트레이닝이 노인 여성의 혈중 VEGF 농도, 골대사 지표 및 골밀도에 미치는 영향

박수빈,이진석,안지영,손왕국,윤성진 국민체육진흥공단 한국스포츠정책과학원 2019 체육과학연구 Vol.30 No.3

[Purpose] The purpose of this study was to investigate the effects of low intensity resistance training with blood flow restriction on serum VEGF, bone markers and bone mineral density in elderly women. [Methods] The subjects were divided into three groups: low-intensity resistance training with blood flow restriction(BFR LRT, n=8); high intensity resistance training(HRT, n=8); low- intensity resistance training (LRT, n=5). Both the BFR LRT and LRT groups worked out knee extension and leg curl exercises at 20% of each estimated one repetition maximum(1RM) and HRT group worked out knee extension and leg curl exercises at 70% of each estimated 1RM 3 days per week for 12 weeks. [Results] As a result after 12 weeks, serum VEGF level have increased significantly among BFR LRT group compared to HRT and LRT groups. Serum Bone ALP level have increased significantly among BFR LRT and HRT groups compared to LRT group. Calcaneus BMD have increased significantly among BFR LRT and HRT groups compared to LRT group. [Conclusions] In conclusion, despite using low-intensity load, BFR LRT is a efficient training alternative to HRT for improving bone metabolism in older women. [목적] 이 연구의 목적은 노인 여성을 대상으로 혈류제한 저강도 근력 트레이닝이 혈중 VEGF 농도, 골대사 지표 및 골밀도에 미치는 영향을 검증하는데 있다. [방법] 이 연구에서는 65세 이상 노인 여성 27명을 연구대상자로 모집하였으며, 연구대상자들은 혈류 제한 저강도 근력 트레이닝 집단(BFR LRT, n=8), 고강도 근력 트레이닝 집단(HRT, n=8), 저강도 근력 트레이닝 집단(LRT, n=5)으로 무작위 분류되었다. 트레이닝은 세 집단 모두 12주간 주3회 knee extension과 leg curl 운동을 하였으며, BFR LRT 집단은 혈류제한과 함께 최대근력의 20% 운동 강도, LRT 집단은 최대근력 20%의 운동 강도, HRT 집단은 최대근력의 70% 강도로 운동하도록 하였다. [결과] 연구 결과, 12주의 트레이닝 기간 후 VEGF 농도는 BFR LRT 집단이 HRT, LRT 집단과 비교하여 유의하게 증가하였다(P<.05). 혈청 Bone ALP 농도는 BFR LRT, LRT 집단이 LRT 집단과 비교하여 유의하게 증가하였다(P<.05). T-score 점수는 BFR LRT, HRT 집단이 LRT 집단과 비교하여 유의하게 증가하였다(P<.05). [결론] 결론적으로, 혈류제한 저강도 근력 트레이닝은 노인 여성의 골대사 지표 개선에 효과적임을 증명함으로써 혈류제한 저강도 근력 트레이닝은 고강도 근력 트레이닝을 대처할 수 있는 효율적인 운동 방법의 하나가 될 수 있을 것으로 생각된다.

16 V 급 NMOSFET 소자의 낮은 게이트 전압 영역에서 출력저항 개선에 대한 연구

김영목,이한신,성만영,Kim, Young-Mok,Lee, Han-Sin,Sung, Man-Young 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.2

In this paper we proposed a new source-drain structure for N-type MOSFET which can suppress the output resistance reduction of a device in saturation region due to soft break down leakage at high drain voltage when the gate is biased around relatively low voltage. When a device is generally used as a switch at high gate bias the current level is very important for the operation. but in electronic circuit like an amplifier we should mainly consider the output resistance for the stable voltage gain and the operation at low gate bias. Hence with T-SUPREM simulator we designed devices that operate at low gate bias and high gate bias respectively without a extra photo mask layer and ion-implantation steps. As a result the soft break down leakage due to impact ionization is reduced remarkably and the output resistance increases about 3 times in the device that operates at the low gate bias. Also it is expected that electronic circuit designers can easily design a circuit using the offered N-type MOSFET device with the better output resistance.

High-temperature hydrogen-reduction process for the preparation of low-oxygen Mo powder from MoO₃

Ku, J.G.,Oh, J.M.,Kwon, H.,Lim, J.W. Pergamon Press ; Elsevier Science Ltd 2017 International journal of hydrogen energy Vol.42 No.4

<P>In this study, a new high-temperature hydrogen-reduction (HTHR) process was applied for the preparation of a low-oxygen Mo powder whereby MoO3 was used as a raw material. The HTHR-prepared Mo powder showed a low oxygen concentration of 1580 ppm, which was obtained at a reduction temperature of 1500 degrees C. From the oxidation-resistance test of the low-oxygen Mo powder, the oxidation resistance of the 1500 degrees C-prepared low-oxygen Mo powder is outstanding. The improved oxidation resistance is derived from the reduced oxygen concentration that can be diffused to the surface where it forms an oxidation layer on the Mo powder. When compared with the conventional hydrogen reduction process, the HTHR process provided an improved oxidation resistance as well as a low oxygen concentration. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>