• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.538-543
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• 2000

The purpose of this study is to develope electrostatic separation system for recycling of mixed waste plastics. The electrostatic separation system is designed and investigated the separation efficiency for separating of mixed waste plastics. Electrostatic separation system consisted of a tribocharger, separator (two electrode), collector (5 tray) and controller (positive/negative high voltage power supply). The tribocharger is a fluidized bed using tribo-electrification mechanism between particles and particles. In experimental results, the tribocharger of the fluidized bed was more effective separation efficiency. It showed the purity of $85{\sim}99\;%$ and the recovery of $80{\sim}98\;%$ from the powder of mixed plastics such as LDPE, HDPE, PP, PS, PET and PVC. Especially, In the separation experiment of Polyvinylchloride(PVC) which generates hazardous hydrogen chloride gas in case of the combustion. its purity was over 99 % and recovery was over 95 %.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.494-499
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• 2004

A ion source using inductively coupled plasma has been tested in order to test its feasibility as a high brightness ion source for focused ion beam. When operating the ion source with filter magentas in front of plasma electrode for a negative ion source, lower remittances are expected. Extracted beam remittances are measured with an Allison-type scanning device for various plasma parameters and extraction conditions. The normalized omittance has been measured to be around 0.2$\pi$mmmrad with beam currents of up to 0.55 ㎃. In particular, noting that multicusp magnets have a role in decreasing the remittance as well as increasing plasma discharge efficiency, transverse magnetic field has been confirmed to be a useful tool fur decreasing remittance via electron energy control.

• 전기화학회지
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• 제23권4호
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• pp.105-112
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• 2020

리튬이온 이차전지용 음극 활물질 중 전환반응을 거치는 전이금속 산화물은 높은 용량을 지니고 있으나, 아직 해결되어야 하는 여러 문제점을 지니고 있다. 본 연구에서는 새로운 음극 활물질로써 망간 피로인산화물(Mn₂P₂O₇) 및 니켈 피로인산화물(Ni₂P₂O₇)과 이를 포함하는 탄소 복합물질을 고상법으로 간단하게 합성하였다. 망간 피로인산화물 및 니켈 피로인산화물의 초기 가역용량은 각각 333 및 340 mAh g^-1의 용량을 나타내었으며, 탄소와 복합재료를 구성하면 각각 433 및 387 mAh g^-1로 가역용량이 증가하였을 뿐만 아니라 초기효율도 약 10% 정도 향상되었다. 망간 피로인산화물과 탄소와의 복합재료로 구성된 활물질이 가장 높은 초기용량과 효율을 지니며, 사이클 성능도 가장 우수하였다. 다중 음이온을 포함하는 망간 피로인산화물은 망간 산화물인 MnO와 비교하였을 때, 음이온의 질량이 크기 때문에 무게당 용량은 낮았지만, 전압곡선이 기울기를 지니는 형태를 나타내면서 충전(lithiation)전압은 0.51에서 0.57 V (vs. Li/Li⁺)로 높아지고, 방전(delithiation)전압은 1.15에서 1.01 V (vs. Li/Li⁺)로 낮아졌다. 따라서, 충전과 방전에서의 전압차이가 0.64 에서 0.44 V로 크게 감소하므로 전지의 전압효율이 개선되며, 방전과정에서 음극전위가 낮아지게 되어 완전지의 작동전압을 높일 수 있다.

• 대한전기학회논문지
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• 제36권11호
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• pp.796-805
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• 1987

The flashover voltages have been investigated for spacer and unbridged-gap in SF6-N2 gas mixtures up to the value of 760(torr. cm), The gap was stressed by DC source The results obtained are as follows` 1) The flashover voltages for an unbridged gap and for a spacer in SF6, N2 and SF6-N2 gas mixtures follow the Paschen's curve. 2) The polarity effects was not observed in both unbridged gap and a spacer which had per ect contact with an electrode. The flashover voltages for negative polatity are lower than those for positive polarity in case of imperfect contact. 3) 3%flashover voltage is decreased by putting a spacer which had perfect contact with an electrode. The spacer which has a gap void shows the lowest flashover voltage. 4) The lowest spacer efficiency was obtained with higher gas pressure & large amount of N2 content. The flashover voltages depend on the gas pressure rather than the spacer efficienty at low value of pd. 5) The flashover voltages of gas mixtures of N2 with SF6 are relatively high, even though the amount of SF6 gas content is small.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권6호
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• pp.328-334
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• 2000

A lithium ion secondary battery using carbon as a negative electrode has been developed. Further improvements to increase the cell capacity are expected by modifying the structure of the carbonaceous material. There are hopes for the development of large capacity lithium ion secondary batteries with long cycle, high energy density, high power density, and high energy efficiency. In the present paper, needle cokes from petroleum were examined as an anode of lithium ion secondary battery. Petroleum cokes, MCL(Molten Caustic Leaching) treated in Korea Institute Energy Research, were carbonized at various temperatures of 0, 500, 700, $19700^{\circ}C$ at heating rate of $2^{\circ}C$/min for lh. The electrolyte was used lM liPF6 EC/DEC (1:1). The voltage range of charge & discharge was 0.0V(0.05V) ~ 2.0V. The treated petroleum coke at $700^{\circ}C$ had an initial capacity over 560mAh.g which beyond the theoretical maximum capacity, 372mAh/g for LiC6. This phenomena suggests that carbon materials with disordered structure had higher cell capacity than that the graphitic carbon materials.

• 전기화학회지
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• 제22권3호
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• pp.128-137
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• 2019

리튬은 가장 가벼운 금속일 뿐만 아니라 낮은 환원전위(-3.04 V vs. SHE)와 큰 이론용량($3860mAh\;g^{-1}$)을 가지고 있어 차세대 음극 소재로 연구되고 있다. 리튬 금속을 전극으로 사용하는 리튬이차전지의 경우 전지의 효율과 에너지 밀도 극대화를 위해 얇은 두께의 리튬 전극이 필요하지만 기존의 리튬 박을 제조하는 물리적인 압연 방법으로는 일정수준 이하의 두께를 가지는 리튬 박을 제조하는데 한계가 있다. 본 연구에서는 물리적인 방법 대신 전해도금법으로 박막의 리튬을 전착하여 전해도금 시 사용되는 전해액의 종류와 전착 조건이 전착 특성 및 전착된 리튬의 전기화학 특성에 주는 영향을 확인하였다. 전착 전해액의 농도가 높을 수록 리튬 덴드라이트(dendrite) 형성 억제에 유리한 크고 둥근 형태의 리튬 입자를 형성하였으며 우수한 stripping 효율 (92.68%, 3M LiFSI in DME) 을 나타냈다. 전착 속도(전류 밀도)의 경우 속도 증가에 따라 리튬이 길이 방향으로 성장하여 길고 끝이 뾰족한 형태를 가지는 경향을 보였으며, 이로 인한 비표면적 증가로 전착된 리튬 전극의 stripping 효율이 감소(90.41%, 3M LiFSI in DME, $0.8mA\;cm^{-2}$)하는 경향을 확인하였다. 두 종류의 염과 용매를 조합하여 얻은 1.5M LiFSI + 1.5M LiTFSI in DME : DOL (1 : 1 vol%) (Du-Co) 전해액에서 전착된 리튬 전극이 가장 우수한 stripping 효율 (97.26%) 및 안정적인 가역성을 보였으며, 이는 염의 분해물로 구성된 전극 표면 피막의 Li-F 성분이 주는 안정성 향상과 피막의 유연성을 부여하는 DOL 효과에 기인한 것으로 추정된다.

• 한국가축번식학회지
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• 제7권2호
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• pp.8-26
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• 1983

Various early pregnancy diagnostic methods have been developed in order to improve the reproductive efficiency in cow, mare, mule, sow, sheep, goat, dog, cat, rabbit, buffalo, camel, elephant, monkey, deer, lion, coipus and guinea pig. These methods include abdominal swelling, abdominal palpation, esturs cylce detection, Lupin test, gonadotropin assay, colostrum injection test, sperm motility assessment, cervical mucus viscosity test, Kaber chromagens method, estrogen test, A Scheim-Zond다 test, spectrophotometric detection of estrogen in urine and feces, boric acid crystraline formation test in urine, oxytocin injection test, diamino-oxidase test, PMSG HA test, behaviour test, Simolus iodine detection test, detection of tryptophane in urine, x-ray method, Cuboni and Lunaas method, vaginal biopsy method, Friedmann Schneider diagnostic method, electrode method, barium chloride detection method, ECG, Doptone method, ultrasound method, ultrasound scanning method, LDH method, rectal palpation method, CL palpation method, radioautography, serum creatine test, serum globulin test, chlormadine method, CAP method, Medata Do, pp.ers method, body fluid test, Plasma oCS detection method, ERIA, LHRH method, negative latex cogulation test and oestrone sulphate detection method. The most reliable methods with high a, pp.icability to farm animals such as sheep, mare, sow and cow are rectal palpation, ultrasound method and hormonal assay in blood and milk. However, they require complicated laboratory works for the early diagnosis of pregnancy and in most cases, the simple and economical methods which are described up to now need a long period of time after conception. Generally, it is possible to detect pregnancy after one estrus cycle, even though it varies depending on the species of animals. For improvement of the reproductive efficiency, it is required to develop a more accurate, economical, simple and early detectable method. It is anticipated that the result of a study on the detection method of EPF(early pregnancy factor) would be a, pp.icable to various animals within 6 hours after conception.

• 한국표면공학회지
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• 제43권6호
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• pp.297-303
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• 2010

The effect of solution acidity and organic additives, polyethylene glycol (PEG), on the trivalent chromium electroplating was systematically investigated in the view point of electroreduction of trivalent chromium ions and solution stability. It was found that solution acidity controlled at pH 2.5 showed the widest current range for bright electrodeposits in the presence of PEG additives, which reduced the local current intensification at high current densities. Through complex interaction between PEG additives and hydrogen ion, that is, solution acidity, electrode potential was moved in the negative direction in the bulk solution, while it shifted in the positive when electric potential was scanned. In conjunction with electrochemical quartz crystal microbalance (EQCM), it was found that PEG additives had a role in promoting the electron transfer to trivalent chromium ion complexes in bulk solution and their adsorption at the electrode surface as well as interfering with hydrogen ion reduction process below pH 2.5. The PEG additives developed the nodular morphology during electroreduction of trivalent chromium ions with the increase of solution acidity and enhanced its current efficiency by maintaining the consumption of complexant, formic acid, at low speed.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.184-187
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• 2007

Hydrogen could be produced from any substance containing hydrogen atoms, such as water, hydrocarbon (HC) fuels, acids or bases. Hydrocarbon fuels couold be converted to hydrogen-rich gas through reforming process for hydrogen production. Even though fuel cell have high efficiency with pure hydrogen from gas tank, it is more beneficial to generate hydrogen from city gas (mainly methane) in residential application such as domestic or office environments. Thus hydrogen is generated by reforming process using hydrocarbon. Unfortunately, the reforming process for hydrogen production is accompanied with unavoidable impurities. Impurities such as CO, $CO_2$, $H_2S$, $NH_3$, and $CH_4$ in hydrogen could cause negative effects on fuel cell performance. Those effects are kinetic losses due to poisoning of electrode catalysts, ohmic losses due to proton conductivity reduction including membrane and catalyst ionomer layers, and mass transport losses due to degrading catalyst layer structure and hydrophobic property. Hydrogen produced from reformer eventually contains around 73% of $H_2$, 20% or less of $CO_2$, 5.8% of less of $N_2$, or 2% less of $CH_4$, and 10ppm or less of CO. Most impurities are removed using pressure swing adsorption (PSA) process to get high purity hydrogen. However, high purity hydrogen production requires high operation cost of reforming process. The effect of carbon dioxide on fuel cell performance was investigated in this experiment. The performance of PEM fuel cell was investigated using current vs. potential experiment, long run (10 hr) test, and electrochemical impedance measurement when the concentrations of carbon dioxide were 10%, 20% and 30%. Also, the concentration of impurity supplied to the fuel cell was verified by gas chromatography (GC).

• 폴리머
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• 제36권4호
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• pp.486-493
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• 2012

칼콘기를 포함하는 광가교성 sulfonated polyimide(SPI) 전해질 고분자를 칼콘기를 가지는 실란 커플링제가 처리된 알루미나 전극에 도포하여 습도센서를 제조하였다. SPI 필름 중 bis(tetramethyl)ammonium 2,2'-benzidinedisulfonate($Me_4N$-BDS)/4,4'-diaminochalcone(DAC)/pyromellitic dianhydride(PA)= 90/10/100 이루어진 습도센서는 20과 95 %RH 영역에서 4.48부터 $2.1k{\Omega}$까지 변화하며 좋은 직선성(Y = -0.04528X+7.69446, $R^2=0.99675$)을 보여주었다. 33 %RH와 94 %RH 사이에서 흡습과 제습과정의 응답속도는 약 79초이며, 가교화된 SPI 필름은 습도를 빠르게 검지할 수 있는 매우 효율적인 감습재료이다. 온도 의존성 계수는 $-0.49%RH/^{\circ}C$이며 습도센서로서 응용시 온도 보상이 필요하다. 또한 센서의 기재를 칼콘을 포함하는 실란 커플링제로 처리한 센서는 가교와 동시에 기재에 접합되어 480시간 이상 내수성, 고온과 고습 안정성 및 장기 안정성이 뛰어남을 알 수 있었다. 이렇게 가교화된 SPI는 상용화된 센서보다 우수한 특성을 보이는 재료로서 응용 가능성을 보여주었다.