Li / V6O13 리튬 폴리머 전지의 성능

김형선,조병원,윤경석,전해수 ( Hyung Sun Kim,Byung Won Cho,Kyung Suk Yun,Hai Soo Chun ) 한국공업화학회 1996 공업화학 Vol.7 No.2

Li/V_6O_(13) 전지의 성능과 poly(acrylonitrile)[PAN]계 폴리머 전해질의 전기화학적인 성질을 조사 하였다. 폴리머 전해질의 이온 전도도는 상온에서 2.3×10^(-3)S/㎝를 보였으며 리튬 전극과의 상용성도 우수하였다 또한 4.3V(vs. Li^+/Li)까지의 전기화학적인 안정성이 있는 것으로 나타났다. Li/V_6O_(13) 전지 반응은 V_6O_(13) 전극과 폴리머 전해질간의 계면저항이 지배적 이었다. V_6O_(13)내의 리튬 이온의 확산 계수값은 2.7×10^(-9)∼4.2×10^(-8)㎠/sec로 나타났다. V_6O_(13) 활물질의 이용률은 C/8(50㎂/㎠)에서 95%였으며 C/4(100㎂/㎠)에서는 82%로 각각 나타났다. The performance of Li/V_6O_(13) cell and the electrochemical properties of polymer electrolyte based on poly(acrylonitrile)[PAN] was investigated. The ionic conductivity of polymer electrolyte showed 2.3×10^(-3)S/㎝ and the compatibility with lithium electrode was excellent. Also, it showed the electrochemical stability up to 4.3V(vs. Li^+/Li). The cell reaction of Li/V_6O_(13) was dominated by the interfacial resistance between V_6O_(13) electrode and polymer electrolyte. The diffusion coefficient of lithium ion within V_6O_(13) was 2.7×10^(-9)∼4.2×10^(-8)㎠/sec. The utilization of V_6O_(13) active material was 95% at C/8(50㎂/㎠) and 82% at C/4(100㎂/㎠), respectively.

Li/V₆O₁₃ 리튬 폴리머 전지의 성능

김형선,조병원,윤경석,전해수,Kim, Hyung-Sun,Cho, Byung-Won,Yun, Kyung-Suk,Chun, Hai-Soo 한국공업화학회 1996 공업화학 Vol.7 No.2

The performance of The performance of $Li/V_6O_{13}$ cell and the electrochemical properties of polymer electrolyte based on poly(acrylonitrile)[PAN] was investigated. The ionic conductivity of polymer electrolyte showed $2.3{\times}10^{-3}S/cm$ and the compatibility with lithium electrode was excellent. Also, it showed the electrochemical stability up to 4.3V(vs. $Li^+/Li$). The cell reaction of $Li/V_6O_{13}$ was dominated by the interfacial resistance between $V_6O_{13}$ electrode and polymer electrolyte. The diffusion coefficient of lithium ion within $V_6O_{13}$ was $2.7{\times}10^{-9}{\sim}4.2{\times}10^{-8}cm^2/sec$. The utilization of $V_6O_{13}$ active material was 95% at C/8($50{\mu}A/cm^2$) and 82% at C/4($100{\mu}A/cm^2$), respectively.

Ti-6Al-4V 티타늄 합금나사의 절삭 특성

김형선,최종근,김동민,류민영,Kim, Hyung-Sun,Choi, Jong-Guen,Kim, Dong-Min,Lyu, Min-Young 한국생산제조학회 2009 한국생산제조학회지 Vol.25 No.1

Titanium is one of the most attractive materials due to their superior properties of high specific strength and excellent corrosion resistance. The applications in aerospace and medical industries demand machining process more frequently to obtain more precise products. Machining of titanium is faced with strong challenges such as increased component complexity i.e. airframe components manufacturing processes. The machining cost on titanium have traditionally demanded high cutting tool consumable cost and slow machining cycle times. Similarly, the high wear of the cutting tools restricts the cutting process capabilities. Titanium screws applied to fasten parts In the several corrosion environment. In the thread cutting of titanium alloys, the key point for successful work is to select proper cutting methods and tool materials. This study suggests a guidance fur selecting the cutting methods and the tool materials to improve thread quality and productivity. Some experiments investigate surface roughnesses, cutting forces and tool wear with change of various cutting parameters including tool materials, cutting methods, cutting speed. As the results, the P10 type insert tip was assured of the best for thread cutting of Ti-6Al-4V titanium alloy. Also the initial depth of infeed was desirable to use the value below 0.5mm as the uniform cutting area method is applied.

리듐 이차전지용 고체고분자전해질의 특성

김형선,백지흠,조병원,윤경석 ( Hyung Sun Kim,Chi Hum Paik,Byung Won Cho,Kyung Suk Yun ) 한국화학공학회 1994 추계학술발표논문집 Vol.- No.-

리튬 2차전지용 poly ( acrylonitrile ) 고분자 전해질 및 LiCoO2 양극 특성에 관한 연구

김형선,조병원,윤경석,전해수 ( Hyung Sun Kim,Byung Won Cho,Kyung Suk Yun,Hai Soo Chun ) 한국화학공학회 1996 화학공학의이론과응용 Vol.2 No.2

리튬이차전지용 Si/Cu/Graphite 복합체 음극의 전기화학적 거동

김형선,정경윤,조원일,조병원,Kim, Hyung-Sun,Chung, Kyung-Yoon,Cho, Won-Il,Cho, Byung-Won 한국전기화학회 2009 한국전기화학회지 Vol.12 No.2

The carbon-coated Si/Cu powders were synthesized by mechanical ball-milling and hydrocarbon gas decomposition methods at high temperature. The carbon-coated Si/Cu powder was used as anode for lithium secondary battery and its electrochemical behavior was investigated. In addition, the carbon-coated Si/Cu/graphite composite anode material was prepared using natural graphite powder and their electrochemical characteristics were compared with natural graphite anode. The specific capacity of carbon-coated Si/Cu anode increased to the initial 10 cycles. The carbon-coated Si/Cu/graphite composite anode exhibited the reversible specific capacity of 450mAh/g and the first cycle efficiency of 81.3% at $0.25mA/cm^2$. The cycling performance of the composite anode was similar to that of pure graphite anode except the reversible specific capacity value.

Redox Flow Battery용 일체화된 흑연/DSA 전극의 전기화학적 특성

김형선,Kim, Hyung-Sun 한국전기화학회 2010 한국전기화학회지 Vol.13 No.2

An assembled-graphite/DSA(Dimensionally Stable Anode) was prepared using graphite powder to increase durability and energy efficiency of redox flow battery and investigated its electrochemical properties in vanadium-based electrolyte. The cyclic voltammetry (CV) was carried out in the voltage range of -0.7V and 1.6V vs. SCE at 5 mV/sec scan rate to analyze vanadium redox reaction. From the CV results, the assembled-graphite/DSA electrode showed a fast couple reaction and good reversibility in 2M $VOSO_4$ + 2.5 M $H_2SO_4$ electrolyte. Therefore, it has been expected that this electrode increases power density as well as energy density of redox flow battery.

Poly ( ethylene oxide ) - Li 계 고분자 전해질의 전기화학적 특성 및 물리적 성질

김형선,조병원,윤경석,전해수 ( Hyung Sun Kim,Byung Won Cho,Kyung Suk Yun,Hai Soo Chun ) 한국공업화학회 1996 공업화학 Vol.7 No.3

분자량이 큰 Poly(ethylene oxide)[PEO] 고분자에 LiClO₄, LiCF₃SO₃ 등의 리튬염과 ethylene carbonate(EC), propylene carbonate(PC) 등의 가소제를 고정화시킨 고분자 전해질의 전기화학적 특성 및 물리적 성질을 조사하였다. 가소제가 첨가된 PEO-Li계 고분자 전해질은 상온에서 10^(-4)S/㎝의 이온 전도도를 보였고 4.5 V(vs. Li^+/Li)까지 높은 전기화학적인 안정성을 나타냄으로써 리튬 2차전지에 적용 가능한 것으로 나타났다. 리튬염 및 가소제의 첨가에 따라 PEO의 결정상이 감소되었고 특히 LiClO₄, PC 등이 LiCF₃SO₃, EC 등에 비하여 더 효과적인 것으로 나타났다. 리튬염의 농도가 증가할수록 고분자 전해질의 유리전이온도(T_g)는 증가되었으며 반면에 융점온도(T_m)는 감소하는 것으로 나타났다. 가소제가 첨가된 고분자 전해질은 6℃에서 결정화 되었다. Electrochemical characteristics and physical properties of polymer electrolyte which immobilized lithium salts such as LiClO₄ and LiCF₃SO₃ and plasticizers such as ethylene carbonate(EC) and propylene carbonate(PC) in high molecular weight polyethylene oxide)[PEO] polymer was investigated. PEO-Li based polymer electrolyte with plasticizers showed ionic conductivity of 10^(-4)S/㎝ at room temperature and high electrochemical stability up to 4.5 V(vs, Li^+/Li), so it can be applied to lithium secondary battery. The crystallinity of PEO decreased with the addition of lithium salts and plasticizers, especially LiClO₄ and PC showed more effective than LiCF₃SO₃ and EC. Glass transition temperature(T_g) of polymer electrolyte increased with increasing lithium salt concentration whereas melting temperature(T_m) decreased. Polymer electrolyte with plasticizers crystallized at 6℃.

연구발표논문초록 ( 공업화학 (2) ) : DSA 전극의 산성용액에서의 양극산소발생

김형선(Hyung Sun Kim),조병원(Byung Won Cho),윤경석(Kyung Suk Yun) 한국화학공학회 1989 추계학술발표회 Vol.- No.-

뇌파와 심전도 분석을 기반으로 한 온열환경 및 조도가 재실자의 업무에 미치는 영향

김형선 ( Hyung Sun Kim ),임재현 ( Jae Hyun Lim ),김형태 ( Hyoung Tae Kim ),김형식 ( Hyoung Sik Kim ),곽원택 ( Won Tack Kuwak ),김진호 ( Jin Ho Kim ) 한국감성과학회 2014 감성과학 Vol.17 No.3

This research analyzed biosignals associated with the change of emotion from lighting felt by the occupants and task type under various indoor thermal environments and illuminance, and examined the biosignals` impacts on work. To this end, the indoor thermal environment was constructed on the basis of PMV (predicted mean vote) index value, and various indoor environments were created by changing the brightness of LED stands. In this manner, a variety of indoor environments were constructed, and experiments were carried out. This research evaluates the sensibility response to lighting through a questionnaire survey in the given environment and incorporates different types of error searches. In this way, changes were analyzed by measuring electroencephalogram (EEG) and electrocardiograms (ECG). As a result, all biosignals on the task type showed significant differences from the thermal environment change. When PMV index value was 0.8 (temperature: 25 ℃, humidity: 50 %), concentration and attention were the most activated. However, the biosignals did not show significant differences from the illuminance change. Concentration on an occupant`s work capability was confirmed to be closely related to the thermal environment. As for the subjective emotional response to lighting, the occupants felt comfort as illuminance was lower, while they felt discomfort as illuminance was higher. However, there were no significant differences from the thermal environment change.