• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.696-702
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• 2018

Recently, the current thermal battery technology needs new materials for electrodes in the power and energy density to meet various space and defense requirements. In this paper, to replace the pellet type Li(Si) anode having limitations of the formability and capacity, electrochemical properties of the lithium anode with high density for thermal batteries were investigated. The lithium anode (Li 17, 15, 13 wt%) was fabricated by mixing the molten lithium and iron powder used as a binder to hold the molten lithium at $500^{\circ}C$. The single cell with 13 wt% lithium showed a stable performance. The 2.06 V (OCV) of the lithium anode was significantly improved compared to 1.93 V (OCV) of the Li(Si) anode. Specific capacities during the first phase of the lithium anode and Li(Si) were 1,632 and $1,181As{\cdot}g^{-1}$, respectively. As a result of the thermal battery performance test at both room and high temperatures, the voltage and operating time of lithium anode thermal batteries were superior to those of using Li(Si) anode thermal batteries. The power and energy densities of Li anode thermal batteries were also remarkably improved.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.217-222
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• 2022

It is very important to analyze the OCV change behavior during the open circuit potential holding (OCV holding) process, which accelerates the evaluation of the electrochemical durability of the PEMFC membrane. In this study, an empirical formula using the experimental data of three MEAs with different durability was created and compared. The durability evaluation time of the reinforced membrane MEA without radical scavenger inside the membrane was 383 h, and the durability evaluation time of the reinforced membrane MEA with radical scavenger inside the membrane was 1,000 and 1,650 h, respectively. The degradation of the membrane was divided into the reversible degradation that can be recovered by activation and the irreversible degradation that is not recovered. The irreversible degradation of the membrane was indicated by an increase in hydrogen permeability, and the change in hydrogen permeability was similar to the irreversible degradation constant c of all three MEAs. The initiation of irreversible deterioration without recovery is indicated by an increase in hydrogen permeability, and the OCV is not recovered due to an increase in hydrogen permeability, so the slope of the OCV recovery line (ORL) decreases, which can be confirmed by an increase in the constant c value of the empirical formula.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.317-345
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• 2022

This study carried out a survey to utilize basic data for the conservation of northern lineage plants that are vulnerable to climate change, targeting algific talus slope of a specific forest biodiversity region in Yeotan-ri, Jeongseon-eup, Jeongseon-gun, Gangwon-do. The survey was conducted by dividing the wind hole into 625 m² inside and 6,925 m² outside based on the wind hole. The vascular flora were identified as 84 families, 203 genera, 296 species, 6 subs., 27 var., 2 for., and a total of 331 taxa. This was found to be about 7% of 4,724 species of vascular plants in Korea. Plants endemic to the Korean peninsula were identified as 19 taxa, including Syringa fauriei, and 11 taxa for rare plants designated by IUCN. Critically endangered grade (CR) was Paeonia obovata 1 taxa, Endangered grade (EN) was Forsythia saxatilis and Prunus choreiana 2 taxa. A total of 78 taxa were florisitc target species, and 19 taxa were classified for indicator plants in the limestone area. As for alien plants, 20 taxa such as Taraxacum officinale were identified, and the naturalization rate was 6.04% and the urbanization rate was 5.33%. Geographical plants of the study area are 2 taxa of Syringa fauriei and Syringa villosa subsp. wolfii.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.362-367
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• 2023

Recently, research and development of proton exchange membrane fuel cells (PEMFC) membranes are progressing in the direction of thinning to reduce prices and improve performance. Demand for hydrogen-powered vehicles for commercial vehicles is also increasing, and their durability should be five times greater than those for passenger vehicles. Despite the thinning of the membranes, the durability of the membranes must be increased five times, so the improvement of the durability of the membranes has become more important. Since the acceleration durability evaluation time also needs to be shortened, the protocol using oxygen instead of air in the existing protocol was applied to a 10 ㎛ thin membrane to evaluate durability. The accelerated durability test (Open circuit voltage holding) was terminated at 720 hours. If the air-based department of energy (DOE) protocol was used, a lifespan of 450,000 km of driving hours would be expected, with a durability of about 1,500 hours. During the chemical durability evaluation, the active area of the electrode decreased by 51%, suggesting that catalyst degradation had an effect on membrane durability. Reducing the catalyst degradation rate is expected to increase membrane durability.

• Korean Journal of Environment and Ecology
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• v.9 no.2
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• pp.147-155
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• 1996

To investigate the structure and the conservation strategy of natural forest at Dongdaesan, Turobong, Sangwangbong Area in Odaesan National Park, 27 plots(20$\times$20m) set up with random sampling method. Three groups were classified by cluster analyses. High positive correlations was proved between Tilia amurensis and Acer pseudo-sieboldianum, Malus faccata and Syringa reticulata var. mandshurica, Prunus padus and Viburnum sargentii, and High negative correlations was proved between Quercus mongolica and pronus padus, Tilia amurensis and Prunus padus, Acer pseudo-sieboldianum and Prunus padus. Species diversity(H') of investigated area was calculated 0.9586~1.1814.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.90-97
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• 1991

A stepping motor can be driven with open-loop or closed-loop control. The major disadvantage of open-loop control is that it is subjected to resonance and instability in certain speed range, and that there is no way to check stalling or error in position. In this paper, a closed-loop control system consisting of a microcomputer, a hybrid stepping motor, a drive, a lead screw, and an encoder which is used as a position sensor is developed. A control program is programmed in assembly language for real time control and the versatile interface adapter(VIA) is used as the interface with the microcomputer. The experimental results of the stepping motor were eliminated on all kinds of inertia load, and maximum start stop pulse rate and maximum slewing pulse rate were also increased about twice respectively.

• LOGISTICS
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• v.2 no.3 s.5
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• pp.18-21
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• 2004

동북아물류 중심 실현을 위해서는 종합물류기업 육성과 중국을 중심으로 하는 물류정책이 필요하다. (사)한국물류협회(회장 서병륜)와 한국로지스틱스학회, 매일경제신문, 물류신문사가 공동으로 주최하고 대신정보통신(주), (주)진양로지스틱스, 로지스올 그룹이 후원한 제10차 물류정책토론회에서 이와 같은 주장이 제기됐다. 지난 3월 23일 전국경제인연합회 회관 대회의실에서 200여명이 참석한 가운데 개최된 토론회에서 서병륜 (사)한국물류협회 회장은 개회사를 통해 ''정부는 중국경제의 역동적 성장으로 인한 위기를 우리의 국부창출을 위한 기회로 전환하고자 동북아 물류중심 로드맵을 발표하고 국가물류체계 개선대책을 내놓는 등 물류산업의 발전을 위해 다각적인 노력을 해오고 있다''며 ''이는 정부뿐만 아니라 물류관계자 모두의 노력 위에서 실현될 것이므로 우리도 이를 위해 매진해야 한다 ''고 말했다. 진형인 한국로지스틱스학회 회장은 인사말을 통해 ''동북아 물류중심화 실현을 위해서는 여러 가지 해야할 과제가 많다''며 ''이와 같은 과제해결을 위한 토론회와 많은 연구가 필요하다''고 말했다. 이번 토론회에서는 ‘동북아 물류중심 실현을 위한 선결과제 및 제도적 지원방안’이라는 주제로 제1테마 ‘중국의 물류 환경 변화와 동북아 물류중심화 전략의 보완방안’, 제2테마 ‘국제경쟁력을 가진 종합물류기업의 효율적 육성방안’으로 나뉘어 해양수산개발원원 임종관 박사와 SJ-GLS의 이병욱 박사가 각각 주제발표를 진행했다.

• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.165-173
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• 2007

In order to survey the prevalence of Toxocara cams in soil of playground in a detached dwelling area, 150 samples were taken from playground 50 unit. The survey was carried out during 3 months from July to September in 2006. The Egg of Toxocara canis were detected in 6 samples (4.0%) from 150 cases of playground. The prevalence of T canis by month was 6.0% in July, 4.0% in August, 2.0% in September, respectively. This study results suggested that the prevalence of T canis were decreased in 2006 compared to 18.5% (30 positive/162 samples) in 2000.

• Journal of agricultural medicine and community health
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• v.23 no.2
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• pp.295-303
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• 1998

Toxocariasis is a parasitic zoonosis caused by infestation of humans with larvae of Toxocara canis, the common roundworm in dogs. Two syndromes have been identified : visceral larva migrans and ocular toxocariasis. In this study we were characterized proteinase activity in crude extracts from liver, lung, kidney and heart of mice infected with Toxocara canis and the dynamics of their changes in different stages of disease. The optimal pH was 5.5. In liver of mice infected with Toxocara canis, the maximun activity of proteinase was observed in 5 day post infection. In lung, the activity reached its maximun on 5th day in A group (infected with 100 embryonated eggs), and on 5th week in B group (infected with 50 embryonated eggs). In kidney, the maximum activity was shown at 6th week in A group, and in B group was shown at 10th day. In early infection, the activity reached its maximun in heart of mice infected with Toxocara canis. As we could see, the dynamics of the changes of proteinase activity in mice is similar in the case of the disease with other biochemical and immunological indices observed in toxocariasis.

• Journal of Hydrogen and New Energy
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• v.21 no.5
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• pp.419-424
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• 2010

The 125kW external reforming (ER) type molten carbonate fuel cell (MCFC) system for developing a commercial prototype has been operated at Boryeong thermal power plant site since the end of 2009. The system consists of 125kW stack with $10,000 cm^2$ effective area, mechanical balance of plant (MBOP) with anode recycle system, and electrical balance of plant (EBOP). The 125kW MCFC stack installed in December, 2009 has been operated from January, 2010 after 20 days pre-treatment. The stack open circuit voltage (OCV) was 214V at initial load operation, which approaches the thermodynamically theoretical voltage. The stack voltage remained stable range from 160V to 180V at the maximum generating power of 120 kW DC. The stack has been operated for 3,270 hours and operated at rated power for 1,200 hours.