• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.60-67
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• 2007

Catalyst coated membrane [CCM] type and catalyst coated substrate [CCS] type of membrane electrode assembly [MEA] were manufactured and evaluated their performance. Degradation test were conducted to find the difference of long term stability in two types of MEA and the factor for performance degradation problem occurred. Performance degradation test of single cell in two different types of MEA were carried out when current density was $200mA/cm^{2}$. The degradation test had proceeded for 230 hours and performance degradation was checked by I-V curve and impedance measurement at regular intervals. Also, MEA before/after operation and changes of catalyst layer were characterized by SEM, TEM, and XRD. Maximum power density of CCM type was higher than that of CCS type. Meanwhile, an increase of particle size of catalyst and an increase of impedance resistance after long term operation were observed. In the case of using CCM type MEA, the performance was deteriorated 38% of initial performance. In the case of using CCS type MEA, the performance was deteriorated 43% of initial performance. In consideration of difference of initial performance, performance of CCM type is higher than that of CCS type but both types had similar problems during degradation test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3398-3405
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• 2010

In this paper we developed a CCM Manager which is a management system to support efficient development, publication and promotion of Clinical Contents Model(CCM)'s outcomes. We derived the functions of manager and user from the analysis of work process from development of CCM to management and publication, designed the database based on CCM architecture, and developed web-based system for each user to easily access and search the contents. CCM Manager supports to share the results between model developers well, distribute and promote the outcomes of model type to general users without manager's manual packaging and publishing it. This paper shows superiority compared with other clinical information model management system in aspects of providing multiple search functions, visual model browsing methods and management functions. The proposed CCM Manager is currently used in process of CCM development, and the analysis of its efficiency with the results will be made in the future.

• The Journal of the Korean dental association
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• v.53 no.11
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• pp.804-816
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• 2015

PURPOSE: The aim of this study was to evaluate the influence of the oxide layer removal process in the Co-Cr-Mo (CCM) abutment after casting procedure on the prosthesis settlement and screw stability. MATERIALS AND METHODS: CCM abutments of four different interface conditions (CCM-M; machined, CCM-O; oxide layer formed, CCM-B; blasted, CCM-P; polished after blasted) and gold abutment (Gold-C; Cast with type III Gold alloy) were used. The initial settling values of abutments were evaluated according to the difference of implant-abutment length when the tightening torques were applied at 5 Ncm and 30 Ncm, and the settling values of abutments caused by loading were evaluated according to the difference of implant-abutment length before and after loading with 250 N, 100000 cycle. The loss ratios of removal torque for abutment screws were evaluated according to the difference in value of removal torques under 30 Ncm tightening torque applied before and after cyclic loading. RESULTS: The CCM-P and CCM-B group showed a higher initial settling value compared with the Gold-C group (P<.05), while the Gold-C group showed the highest settling values caused by loading (P<.05) and no significant differences were observed for between CCM groups (P>.05). The loss ratio of removal torque values for the CCM-B, CCM-P groups did not differ significantly from that of the Gold-C group (P>.05). CONCLUSION: Even though the oxide layer was removed by different methods, CCM abutment with internal conical connection structure showed lower abutment settling and similar screw loosening after cyclic loading compared with gold abutment.

• Journal of Periodontal and Implant Science
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• v.51 no.1
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• pp.40-52
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• 2021

Purpose: Various crosslinking methods have been introduced to increase the longevity of collagen membranes. The aim of this study was to compare and evaluate the degradation and bone regeneration patterns of 3 collagen membranes. Methods: Four 8-mm-diameter circular bone defects were created in the calvaria of 10 rabbits. In each rabbit, each defect was randomly allocated to 1) the sham control group, 2) the non-crosslinked collagen sponge (NS) group, 3) the chemically crosslinked collagen membrane (CCM) group, or 4) the biphasic calcium phosphate (BCP)-supplemented ultraviolet (UV)-crosslinked collagen membrane (UVM) group. Each defect was covered with the allocated membrane without any graft material. Rabbits were sacrificed at either 2 or 8 weeks post-surgery, and radiographic and histologic analyses were done. Results: New bone formed underneath the membrane in defects in the CCM and UVM groups, with a distinctive new bone formation pattern, while new bone formed from the base of the defect in the NS and control groups. The CCM maintained its shape until 8 weeks, while the UVM and NS were fully degraded at 8 weeks; simultaneously, sustained inflammatory infiltration was found in the margin of the CCM, while it was absent in the UVM. In conclusion, the CCM showed longer longevity than the UVM, but was accompanied by higher levels of inflammation. Conclusions: Both the CCM and UVM showed distinctive patterns of enhancement in new bone formation in the early phase. UV crosslinking can be a biocompatible alternative to chemical crosslinking.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.660-660
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.530-537
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• 2017

Composted animal manure added for improving soil quality and enhancing crop productivity can lead to greenhouse gas emissions such as nitrous oxide ($N_2O$) by processes of nitrification and denitrification. In addition, the amount of $N_2O$ emission from composted manure amended soils can vary greatly with composted manure type or different soil type. Therefore, the influence of cattle composted manure on $N_2O$ emissions was evaluated during growth of sweet potato (Ipomoea batatas). The treatments included control, conventional fertilization (CF), and CF + cattle composted manure (CCM) $10Mg\;ha^{-1}$ were applied in the spring. $N_2O$ emissions were significantly affected by composted manure and chemical fertilizer and the CCM had greater N2O emissions compared with other treatments. The majority of $N_2O$ emissions occurred shortly after composted manure and chemical fertilizer application compared with the rest of the growing seasons for all treatments. Also, $N_2O$ flux was associated with water-filled pore space (WFPS) at all treatments. On average of $N_2O$ emission accumulation, the CCM was 1.5 times greater than control treatment while there was no difference between CF and control.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.2
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• pp.65-72
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• 2004

Switching power supply systems are widely used in many industrial fields. Power factor correction (PFC) circuits have a tendency to be applied in new power supply designs. The input active power factor correction (APFC) circuits can be implemented in either the two-stage approach or the single-stage approach. The two-stage approach can be classified into boost type PFC circuit and dc/dc converter. The power factor correction circuit with a boost converter used as an input power source is studied in this paper. In a boost power factor correction circuit there are two feedback control loops, which are a current feedback loop and a voltage feedback loop. In this paper, the regulation performance of output voltage and compensator to improve the transient response presented at the continuous conduction mode (CCM) of the boost PFC circuit is analyzed. The validity of designed boost PFC circuit is confirmed by MATLAB simulation and experimental results.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.195-196
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• 2012

본 논문에서는 저가형 고효율의 탭인덕터 벅-부스트 마이크로 인버터를 제안한다. 제안하는 인버터는 정상상태 연속모드(CCM)에서 단상전력계통에 고역률의 정현파전류를 공급할 수 있는 새로운 구조이다. 강압시에는 벅모드로 동작하며, 승압시에는 탭인덕터 부스트 모드로 동작한다. 정류형태의 전류를 2차측에 공급하면, 낮은 주파수를 사용하는 전파정류 인버터가 고역률의 교류 파형으로 변환한다. 벅부스트에 탭인덕터를 적용함으로써 권선비에 따른 시비율을 조절할 수 있어 극단적인 승압시에도 벅부스트의 도통을 적절히 유지할 수 있다. 제안하는 인버터는 정상상태 연속모드(CCM)에서 PSIM을 통해 시뮬레이션을 하여 증명하였다.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.347-353
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• 2006

A helium permeation type standard leak calibration system has newly developed by using dynamic gas expansion method. The measurement range was extended lower to $10^{-6}$ Pa L/s for participating CCM (Consultative Committee for Mass and Related Quantities) standard leak key comparison. For the system, pressure ratios of high and ultra-high vacuum chamber and porous plug conductance for helium gas were determined. By using the system, a permeation type standard leak of $5.6{\times}10^{-4}$ Pa L/s range was calibrated. The calibration result showed that the difference between standard commercial leak was 11.1 %.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.189-197
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• 2017

This paper elaborates two novel proposed topologies (type-I and type-II) of the high step-up DC-DC converter using switched inductor and voltage multiplier cell. The advantages of these proposed topologies are the less voltage stress on semiconductor devices, low device count, high power conversion efficiency, high switch utilization factor and high diode utilization factor. We analyze the Type-II topologies operating principle and mathematical analysis in detail in continuous conduction mode. High-intensity discharge lamp for the automotive application can use the derived topologies. The proposed converters give better performance when compared to the existing types. Also, it is found that the proposed type-II converter has relatively higher voltage gain compared to the type-I converter. A 40 W, 12 V input voltage and 72 V output voltage has developed for the type-II converter and the performances are validated.