http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
이계중 선문대학교 대학원 1998 논문집 Vol.2 No.-
The polymer electrolytes, lithium ion conductor, prepared by polymerizing the mixtures of polymerizable PEO-oligomer, plasticizer for enhancing ionic conductivity and SARAN. The ionic conductivites of the polymer electrolytes were measured by impedance. The "SARAN", which is a copolymer between poly(vinylidene chloride) and poly(acrylonitrile), purchased from Dow Chemical Co. was used as matrix polymer due to its high solubility in PEO acrylate system. After adding proper initiators and lithium salts, ion-conducting complexes were obtained as thick films by thermal polymerizations, and measurements of physical properties such as impedance were performed varying temperatures and plasticizer contents. As the temperature goes up, the ionic conductivity of the polymer electrolytes increases as expected, since the movement of chain and the mobility of lithium ion are enhanced. Plasticizer were added to this system to improve the ionic conductivity with low weight-percentage, because adding plasticizer made the polymerization difficult.
PAN-PVDF-PEGME Blend계 고분자전해질의 전기화학적 특성
류광선,이계중,류광경,강성구,장순호,Ryu, Kwang Sun,Lee, Gye Joong,Liou, Kwang Kyoung,Kang, Seong Gu,Chang, Soon Ho 대한화학회 1999 대한화학회지 Vol.43 No.2
PAN-PVDF-PEGME 블랜드(blend)계의 고분자전해질을 만들어 전기화학적인 특성을 조사하였으며 PEGME의 첨가에 따른 물성변화를 측정하였다. PEGME가 첨가되면서 PVDF의 결정성은 감소하고, 이온 전도도는 대부분 $∼10^{-3}S/cm$의 이온전도도를 나타내므로 고분자전해질로 사용이 가능하다. 또한 이온전도도의 온도의존성으로부터 PEGME의 첨가양이 증가할수록 효과적으로 높은 이온전도도를 갖는 통로가 생겨 이온전도도가 증가하는 것으로 예상할 수 있다. SPE 2(10 wt% PEGME)에서 가장 큰 양이온 수율을 나타내고 있으며 PEGME의 양이 증가할 수록 감소하는 것을 알 수 있다. PEGME를 첨가하지 않은 SPE 1(PAN-PVDF계) 고분자전해질의 전기화학적으로 안정한 영역은 ∼4.3 V인 반면에 PEGME를 첨가한 SPE 2-4(PAN-PVDF-PEGME계) 고분자전해질은 ∼4.6 V까지 전기화학적으로 안정한 것을 알 수 있다. 또한 이 고분자전해질을 사용하여 전지를 구성하여 충방전 성능을 비교하여 보면 PEGME를 첨가함에 따라 방전 용량이 증가함을 알 수 있다. 즉 PEGME를 첨가함에 따라 이온전도도가 증대되며, 전기화학적으로 안정한 영역이 넓어질뿐만 아니라 전지구성시 방전 성능도 향상됨을 알 수 있다. The electrochemical properties of PAN-PVDF-PEGME blend polymer electrolyte system are investigated and the physical properties are also measured with varying the content of PEGME. This PEGME partially reduces the crystallinity of PVDF. The ionic conductivities of the polymer electrolytes are about $10^{-3}S/cm$, which may be applicable to a constituent of lithium secondary battery. From the temperature dependence of ionic conductivity, it is suggested that the ionic conductivity increases with the PEGME content due to the fomation of effective ion-conducting path. The cation transference number reaches its maximum value for the electrolytes (SPE 2) with 10 wt% PEGME and then decreases for further increase of PEGME contnet. The electrochemically stable range of SPE 1 (without PEGME) is about 4.3 V, but SPE 2-4 (PAN-PVDF-PEGME system) is about 4.6 V. When these polymer electrolyte are used as electrolyte in rechargeable battery and the cell performances are tested, the discharge capacity increses with the amount of PEGME. Therefore, PEGME increases the ionic conductivity, extends the electrochemical stable range, and finally improves the discharge capacity of cell adopting the electrolyte system.
Experimental study on heat transfer performance of a two-phase single thermosyphon using HFE-7100
오상현,최종원,이계중,전원표,조형희,김성일 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10
In this study, the heat transfer performance of a two-phase single thermosyphon was experimentally measured and compared with respect to the aspect ratio and filling ratio. For the control experiments, we prepared three 1 m-long thermosyphons with the ratio of evaporator and condenser length by 5:5, 4:6 and 3:7. The working fluid, HFE-7100 was selected to consider the evaporator heat source temperature. The experiments were carried out with respect to the filling ratio and cooling air velocity. As a result, the highest heat transfer rate (about 1.0 kW) was obtained at the filling ratio of 40 % with the length ratio of 5:5 and the cooling air velocity of 2.0 m/s. Among the various parameters, we suggest that the filling ratio and the length ratio play a key role in the heat transfer performance. Out of the experimental data, we suggest the Kutateladze number based correlation between the heat transfer and operating parameters in the thermosyphon using HFE-7100 within the error of ±2 %.