In commercial solar cells, the pattern of the front electrode is critical to effectively assemble the photo generated current. The power loss in solar cells caused by the front electrode was categorized as four types. First, losses due to the metallic resistance of the electrode. Second, losses due to the contact resistance of the electrode and emitter. Third, losses due to the emitter resistance when current flows through the emitter. Fourth, losses due to the shading effect of the front metal electrode, which has a high reflectance. In this paper, optimizing the number of finger on a 4 ´ 4 solar cell is demonstrated with known theory. We compared the short circuit current density and fill factor to evaluate the power loss from the front metal contact calculation result. By experiment, the short circuit current density(Jsc), taken in each pattern as 37.61, 37.53, and 37.38 mA/ cm2 decreased as the number of fingers increased. The fill factor(FF), measured in each pattern as 0.7745, 0.7782 and 0.7843 increased as number of fingers increased. The results suggested that the efficiency(Eff) was measured in each pattern as 17.51, 17.81, and 17.84 %. Throughout this study, the short-circuit current densities(Jsc) and fill factor(FF) varied according to the number of fingers in the front metal pattern. The effects on the efficiency of the two factors were also investigated.

The addition of a large amount of alloying elements reduces the compactibility and increases the compacting pressure, thereby shortening the life of the compacting die and increasing the process cost of commercial PM steel. In this study, the characteristic changes of Fe-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P alloys are investigated according to the Si contents to replace the expensive elements, such as Ni. All compacts with different Si contents are fabricated with the same green densities of 7.0 and 7.2 g/cm3. The transverse rupture strength (TRS) and sintered density are measured using the specimens obtained through the sintering process. The sintered density tends to decrease, whereas the TRS increases as the Si content increases. The TRS of the sintered specimen compacted with 7.2 g/cm3 is twice as high as that compacted with 7.0 g/cm3.

Recently EC-MBR (Elctrocoagulation - Membrane Bio Reactor) has been suggested as one of alternative processes to overcome membrane fouling problems. Most important operational parameters in the EC-MBR are known to current density and contact time. Their effect on membrane filtration performances has been reported well, however, quantitative interrelationship between both parameters not been investigated yet. The purpose of this study is to give a kinetic model suggesting the current density and the contact time required to reduce the membrane fouling. The 4 different set of current densities (2.5, 6, 12 and 24 A/m2) and contact times (0, 2, 6 and 12 hr) were selected as operational parameters. After each electro-coagulation under the 16 different conditions, a series of membrane filtration was carried out. The membrane fouling decreased as the current density and contact time increased, Total fouling resistances under different conditions, Rt(=Rc+Rf) were calculated and compared to those of the controls (R0), which were calculated from the data of experiments without electro-coagulation. A kinetic approach for the fouling reduction rate (Rt / R0) was carried out and the equation ρi0.46t=7.0 was obtained, which means that the product of current density and the contact time needed to reduce the fouling in certain amounts (in this study, 10% of fouling reduction) is always constant.

Densities of molten salt mixtures of eutectic LiCl-KCl with UCl3, CeCl3, or LaCl3 at various concentrations (up to 13 wt%) were measured using a liquid surface displacement probe. Linear relationships between the mixture density and the concentration of the added salt were observed. For LaCl3 and CeCl3, the measured densities were significantly higher than those previously reported from Archimedes’ method. In the case of LiCl-KCl-UCl3, the data fit the ideal mixture density model very well. For the other salts, the measured densities exceeded the ideal model prediction by about 2%.

For the effective seedling production of the hard shelled mussel, Mytilus coruscus, this study assessed the effects of the dietary value of live food, density, water temperature and salinity on growth and survival rate of the larvae. The optimal survival rate and growth rate were examined under differing conditions of water temperature, salinity, and rearing density for 30 days. The three groups were provided different feeding organisms, such as Isochrysis galbana and Teleaulax suecica. The mixtures were provided at a rate of 5×104 cell mL-1. The best growth was observed in the group with conditions 21℃ water temperature (16.2±9.1 μm), 33 psu of salinity (16.82±3.9 μm), 2500 individual m-2 (17.2±5.9 μm), and fed with 5×104 cell mL-1 of I. galbana and T. suecica mixture (16.0±7.3 μm). The highest survival rate was found in the group at conditions 18℃ water temperature (66.4%), 33 psu of salinity (24.4%), 2500 individual m-2 (65.8%), and fed with 5×104 cell mL-1 of I. galbana and T. suecica mixture (58.8%). We therefore conclude that the suitable culture conditions for the stable production of hard shelled mussel artificial seedlings was at 18 to 21℃ of temperature, 30 to 33 psu of salinity, 2500 to 5000 individual m-2 of rearing density, and feeding supplement of 5×104 cell mL-1 of I. galbana and T. suecica mixture under semi running water system.

Spherical-type zirconia granules are successfully fabricated by a spray-drying process using a water solvent slurry, and the change in the green density of the granule powder compacts is examined according to the organic polymers used. Two organic binders, polyvinyl alcohol (PVA) and 2-hydroxyethyl methacrylate (HEMA), which are dissolved in a water solvent and have different degrees of polymerization, are applied to the slurry with a plasticizer (polyethylene glycol). The granules employing a binder with a higher degree of polymerization (PVA) are not broken under a uniaxial press; consequently, they exhibit a poor green density of 2.4 g/cm3. In contrast, the granule powder compacts employing a binder with a lower degree of polymerization (HEMA) show a higher density of 2.6 g/cm3 with an increase in plasticizer content. The packing behavior of the granule powders for each organic polymer system is studied by examining the microstructure of the fracture surface at different applied pressures.

Through density functional theory calculations, to provide insight into the origins of the catalytic activity of Au nanoparticles (NPs) toward oxidation reactions, we have scrutinized the oxygen adsorption chemistry of 9 types of small unsupported Au NPs of around 1 nm in size (Au13, Au19, Au20, Au25, Au38, and Au55) looking at several factors (size, shape, and coordination number). We found that these NPs, except for the icosahedral Au13, do not strongly bind to O2 molecules. Energetically most feasible O2 adsorption that potentially provides high CO oxidation activity is observed in the icosahedral Au13, our smallest Au NP. In spite of the chemical inertness of bulk Au, the structural fluxionality of such very small Au NP enables strong O2 adsorption. Our results can support recent experimental findings that the exceptional catalytic activity of Au NPs comes from very small Au species consisting of around 10 atoms each.

Activated carbons (ACs) have been used as electrode materials of electric double-layer capacitors (EDLC) due to their high specific surface areas (SSA), stability, and ecological advantages. In order to make high-energy-density ACs for EDLC, petroleum pitch (PP) precarbonized at 500–1000°C in N2 gas for 1 h was used as the electrode material of the EDLC after KOH activation. As the pre-carbonization temperature increased, the SSA, pore volume and gravimetric capacitance tended to decrease, but the crystallinity and electrode density tended to increase, showing a maximum volumetric capacitance at a medium carbonization temperature. Therefore, it was possible to control the crystalline structure, SSA, and pore structure of AC by changing the pre-carbonization temperature. Because the electrode density increased with increasing of the pre-carbonization temperature, the highest volumetric capacitance of 28.4 F/cc was obtained from the PP pre-carbonized at 700°C, exhibiting a value over 150% of that of a commercial AC (MSP-20) for EDLC. Electrochemical activation was observed from the electrodes of PP as they were pre-carbonized at high temperatures above 700°C and then activated by KOH. This process was found to have a significant effect on the specific capacitance and it was demonstrated that the higher charging voltage of EDLC was, the greater the electrochemical activation effect was.

어떤 해역의 해상교통혼잡도를 평가하는 데 있어서 단위 시간당 항행 척수인 교통량을 분석하는 것보다 어떤 시간 단면에 존재하는 단위 면적당의 밀집도 분석을 활용하는 것이 합리적일 수 있다. 본 연구에서는 해상교통안전진단 대행기관의 해상교통혼잡도 평가기법을 표준화하고, 선박톤급별 환산교통량 사용으로 인한 평가오차를 최소화하기 위하여 새로운 방안을 찾고자 한다. 이를 해결하기 위해 선박자동식별장치(Automatic Identification System, AIS)의 통항선박 데이터를 활용하여 항로구간면적 대비 식별된 개개의 통항선박이 갖고 있는 점용영역의 면적을 합산한 값과의 백분율을 해상교통혼잡도로 평가하는 방안을 제시하였다. 새로운 모형에서는 정보통신기술의 획기적인 발달로 인해 실제 데이터 사용이 가능하여 환산 데이터에 의한 오차발생을 줄일 수 있고, 항로구간별 해상교통혼잡도 평가도 가능하게 되었다.

도시 스프롤 정의를 구성하는 핵심적인 두 가지 요소는 저밀도와 분절화이다. 밀도를 기반으로 스프롤을 측정하는 경우 분절화 정도를 파악할 수 없고, 분절화를 중심으로 스프롤을 측정하는 경우 밀도 변화를 고려하기 어렵다. 본 연구의 목적은 밀도와 분절화 정도를 동시에 고려하는 새로운 스프롤 측정치를 고안하는 것이다. 이를 위해 동일한 측정 범위를 갖는 밀도 기반의 스프롤 지수와 두 개의 공간구조 기반 스프롤 지수인 인접 통계량과 분할 지수를 가중치 기법을 이용하여 결합하였다. 이 새로운 측정치를 밀도-공간구조 기반 스프롤 지수로 명명하였다. 밀도, 인접 정보 및 도시화된 지역의 면적을 이용하여 지수를 손쉽게 계산할 수 있고 결합한 세 지수의 측정 범위와 해석 방향이 동일하기 때문에 개발된 지수의 해석이 직관적이다. 사례분석의 결과는 개발된 지수가 밀도기반 접근과 공간구조 기반 접근의 단점을 보완할 수 있음을 보여준다.

The nesting behavior, reproduction, fruit set and shape of O. cornifrons varied significantly with the released sex ratio of O. cornifrons. A female : male sex ratio of 1 : 2 was resulted in a 3.4 to 6.7 fold higher than other sex ratio in a nesting behavior. A ratio of 1 : 2 resulted in a 1.2-fold nesting rate, which was slightly higher than other nesting rates. Releasing only males resulted in a 2.4-fold greater amount of fruit set in non-pollinated sites. A sex ratio of 1 : 2 gave a slightly higher shape index and a 1.2 to 1.6-fold lower asymmetric index than other sex ratios. There was no significant difference between female release numbers in fruit set, and 100 to 200 females gave a slightly higher shape index than 400 females. Thus, we determined that 200 females should be released per 2,000㎡ and that the sex ratio of females to males should be 1 : 2.

섬진강 일대에 서식하는 두꺼비(Bufo bufo gaugauizans) 및 두꺼비서식처를 보호하기 위한 방안을 모색하고자 2014년부터 2016년까지 하동군 악양면에서 두꺼비 모니터링을 실시하였다. 연구결과를 바탕으로 두꺼비 서식의 주요 위협시기와 위협요인을 밝힘으로써 합리적이고 현실적인 보전 및 관리방안을 수립하였다. 연구지역인 하동군 악양면 일대에는 총 14개의 습지가 발달해 있다. 2015년 조사결과 왕버들군락습지, 연꽃군락 습지, 입석상제, 노전소류지, 신흥하제 등 5개 지점에서 두꺼비가 산란하였으며, 2016년 조사결과 신규 산란지인 정서제 1곳이 추가로 확인되었다. 한편, 2015년에 텃개소류지, 중간소류지, 신흥상제 등 3개 지점은 매립되어 주차장, 주거지 및 경작지 등으로 이용되어 산란지 기능을 완전히 상실하였다. 그리고 용정소류지, 신대제 2개 지점은 두꺼비의 주요 번식기인 2~4월 기간 동안 일정수준의 저수량을 갖추지 못하고 있어 두꺼비가 산란하지 않았다. 그리고 마지막으로 봉대천 하류, 동정호, 입석하제 3개 지점은 평소 일정수준의 저수량을 유지하고 있었으나, 두꺼비가 산란하지 않았다. 동정호 일대 경관 조사결과와 생물상 조사결과를 바탕으로 두꺼비의 주요 위협요인을 분석한 결과 성체 두꺼비의 산란기인 2월~3월과 아성체 두꺼비의 이동기인 5월로 분석되었으며, 이는 로드킬로 인한 피해가 컸다. 또한 잠재적 포식자로 수달, 삵, 너구리 등의 포유류, 백로류, 오리류, 까마귀류의 조류, 황소개구리, 유혈목이, 남생이, 자라 등 양서·파충류와 두꺼비 유생의 포식자인 노린재목 수서곤충이 확인되었다. 한편, 두꺼비서식의 주요 위협요인은 산란지의 감소 및 축소이다. 두꺼비는 이동성이 낮고, 서식지가 좁은 양서류의 생태특성상 산란지의 환경변화에 따라 크게 영향을 받았다. 두꺼비가 산란할 수 있는 저수지가 매립으로 인하여 사라지거나, 두꺼비의 주요 번식기인 2~4월 기간 동안 일정수준의 수량을 유지하지 못하는 경우, 그 해에는 두꺼비의 번식이 불가능했다. 두꺼비의 서식처를 보전하기 위해서는 첫째, 두꺼비의 산란공간을 확보하여야 한다. 두꺼비의 산란지로 이용될 수 있는 저수지가 매립되지 않아야하며 저습지관리 및 서식공간을 증대시켜 산란공간을 확보하여야 한다. 둘째, 수로와 농로의 관리가 필요하다. 계류로부터 저수지로 유입되는 수로에 낙엽이나 토석 등이 쌓이지 않게 관리하고 두꺼비산란지 인근 농수로에서 양서류가 빠지면 출구와 연결된 생태적 보조시설이 없는 경우 탈출이 거의 불가능하므로 양서류 탈출구와 같은 시설을 설치해야 한다. 셋째, 두꺼비의 주요 번식기인 2~4월 기간동안 두꺼비가 산란하고 유생단계를 보낼 수 있도록 일정수준의 수량을 유지 관리해야한다.

Dyslipidemia, defined as elevated triglyceride (TG), total- and LDL-C, and/or decreased HDL-C levels, is considered a principal risk factor for cardiovascular disease. The low-density lipoprotein receptor (LDLR) family has been considered a key player in the prevention of dyslipidemia. The LDLR family consists of cytoplasmic membrane proteins and plays an important role not only in ligand–receptor binding and uptake, but also in various cell signaling pathways. Emerging reports state that various functional ingredients dynamically modulate the function of the LDLR family. For instance, oats stimulated the LDLR function in vivo, resulting in decreased body weight and improved serum lipid profiles. The stimulation of LRP6 by functional ingredients in vitro activated the Wnt/β-catenin pathway, subsequently suppressing the intracellular TG via inhibition of SREBP1, PPARγ, and C/EBPα. Furthermore, the extract of Cistanchetubulosa enhanced the expression of the mRNA of VLDLR, followed by a reduction in the serum cholesterol level. In addition, fermented soy milk diminished TG and total cholesterol levels while increasing HDL-C levels via activation of LRP1. To summarize, modulating the function of the LDLR family by diverse functional ingredients may be a potent therapeutic remedy for the treatment of dyslipidemia and cardiovascular diseases.

Pressure retarded osmosis (PRO) processes can be implemented on a number of water types, using different technologies and achieving various power outcomes. In this study, Sewage facility effluent was used for feed solution of PRO and synthetic NaCl water for draw solution. This study was conducted to investigate effect of water quality of pretreatment on power density and flux decline in PRO process. The results show that organic and particulate foulants have to be removed for more stable operation. Flourescence technique with EEM enables to investigate the chemical properties of aquatic organic matter by extracting spectral information. Humic/fulvic matters and soluble microbial by-products were analyzed as the most affecting factors on the PRO performance. As a result of analyzing the whole system based on the energy consumption of the unit process, specific energy consumption(SEC) of the applicable technology for PRO pre-treatment should be about 0.2 kWh/m3 or less.