절화용 수국 4품종(‘Magical Amethyst’, ‘Magical Emerald’, ‘Magical Pearl’, ‘Magical Sneeuwbal’)의 상자재배시 배지의 종 류 및 배양액의 EC 농도가 개화에 미치는 영향을 구명하기 위하여 본 실험을 수행하였다. 분홍색 계열인 수국 ‘Magical Amethyst’의 경우, 개화는 7월 4일에서 7월 17일 사이에 이루어 졌다. 식물체당 개화율은 코코피트:원예용상토(1:1, v/v), 원예 용상토 그리고 펄라이트에서 75% 이상으로 나타났으며 분지수 당 개화율은 펄라이트의 EC 0.8dS·m-1에서 85%로 가장 높게 나타났다. 절화장은 코코피트의 EC 0.8dS·m-1에서 77.3cm로 가장 길게 나타났으며 화폭은 펄라이트의 EC 0.8dS·m-1에서 19.4cm로 가장 컸다. 또 다른 분홍색 계열인 수국 ‘Magical Emerald’에 있어서 개화는 5월 18일에서 6월 12일 사이에 이루 어졌다. 식물체당 개화율은 모든 처리에서 거의 100%로 높게 나타났으며 분지수당 개화율은 코코피트:원예용상토(1:1, v/v) 와 암면의 EC 0.8dS·m-1에서 100%를 보였다. 절화장과 화폭은 각각 원예용상토의 EC 1.4dS·m-1에서 62.1cm 그리고 25.8cm 로 가장 크게 나타났다. 흰색 계열인 수국 ‘Magical Pearl’의 경 우, 개화시기는 5월 30일에서 6월 8일이었으며 식물체당 개화율 은 대부분의 처리에서 75%를 보였으며 암면과 펄라이트의 EC 0.8dS·m-1에서 분지수당 개화율이 95.8%로 가장 높게 나타났 다. 절화장은 원예용상토의 EC 1.6dS·m-1에서 53.7cm로 가장 길었으며 화폭은 암면의 EC 0.8dS·m-1에서 24.7cm로 가장 컸 다. 흰색 계열인 수국 ‘Magical Sneeuwbal’에 있어서 개화는 5월 20일에서 6월 25일 사이에 이루어졌다. 식물체당 개화율은 일반 적으로 코코피트와 원예용상토에서 양호하게 나타났다. 절화장 과 화폭은 원예용상토의 EC 1.6dS·m-1과 EC 1.4dS·m-1에서 각각 71.7cm 그리고 24cm로 가장 높았다.

The effect of CNT diameters on properties of CNT-polyamide composites was investigated such as electrical conductivity, tensile strength and thermal conductivity. To get different diameter distributions of CNTs, several portions of Mo and Fe in Mo-Fe/MgO catalysts were synthesized by a combustion method at 600℃. And all CNTs growed at 900℃ with 3 SLM methane and 1 SLM hydrogen for 40min. Four kinds of CNTs with different diameter distributions, such as 1~3nm, 3~7nm, 7~13nm, and 10~30nm, were selected to make CNT-polyamide composites. Each composite was manufactured by a solution mixing using bar-type ultra-sonicator in the CNT portions from 1phr to 50phr. And electrical conductivity, tensile strength, and thermal conductivity were measured. Three properties of CNT-polyamide composite, manufactured with 10nm diameter, were more excellent compared to other composites, with electrical conductivity  Ω at 7phr, thermal conductivity 2.4.W/mK at 40phr, tensile strength 60MPa at 30phr. CNTs with a diameter of 10nm were superior to other diameters for the multi-functional composite such as CNT-polyamide composites.

This paper investigates the dependency of the critical content for electrical conductivity of carbon powder-filled polymer matrix composites with different matrixes as a function of the carbon powder content (volume fraction) to find the break point of the relationships between the carbon powder content and the electrical conductivity. The electrical conductivity jumps by as much as ten orders of magnitude at the break point. The critical carbon powder content corresponding to the break point in electrical conductivity varies according to the matrix species and tends to increase with an increase in the surface tension of the matrix. In order to explain the dependency of the critical carbon content on the matrix species, a simple equation (Vc* = [1 + 3(γc1/2 − γm1/2)2/(ΔqcR]−1) was derived under some assumptions, the most important of which was that when the interfacial excess energy introduced by particles of carbon powder into the matrix reaches a universal value (Δqc), the particles of carbon powder begin to coagulate so as to avoid any further increase in the energy and to form networks that facilitate electrical conduction. The equation well explains the dependency through surface tension, surface tensions between the particles of carbon powder.

감자 가공용 신품종‘새봉’의 무병주 대량생산을 위하여 microponic system에서 배양액의 농도변화가 감자 소식물체 생육에 미치는 영향을 구명하고자 수행 하였다. 조절한 감자 배양액의 농도는 EC 0.2, 0.6, 1.0, 1.4, 1.8, 14.0dS·m−1수준 이었으며 감자 조직배양묘는 생장점과 잎을 2개 포함한 1.5cm길이로 잘라 50mL 유리병(glass vial) 에 1개씩 치상하여 18일, 또는 21일간 2회에 걸쳐 하였다. 배양액량은 용기 당 2mL씩 넣고 10일 후 1 mL를 첨가 하였으며, 환경조건은 일장 16시간, 온도 23 ± 1oC, 40mmol−2·s−1의 백색 LED에서 실험 I의 배양액농도는 EC 0.2, 1.0, 14dS·m−1였으며, 실험 II의 배양액농도는 0.6, 1.0, 1.4, 1.8dS·m−1로 조정하였다. 치상 7일 후 소식물체의 생존율은 0.2dS·m−1에서 90%, 0.6dS·m−1에서 100%, 1.0dS·m−1에서 100%, 1.4dS·m−1에서 0%, 1.8dS·m−1에서 0%, 14.0dS·m−1에서 0% 이었다. 배양액의 전기전도도를 1.0dS·m−1으로 조절한 처리에서 이식 2일 후 뿌리가 발육 되어 소식물체 생육이 왕성하게 생장하여 18일 만에 7개 의 엽, 길이 5cm, 생중 0.5g이상의 식물체로 생육하였다. 배양액의 농도를 0.6dS·m−1으로 조절한 처리에서는 이식 4일 후부터 뿌리가 발육되어 21일 후 5개의 엽, 길이 4cm, 생중 0.2g을 가진 식물체로 생육하였다. 따라서 microponic system에서 무병 감자 묘 대량생산을 위해서는 감자배양액의 전기전도도를 0.6~1.0dS·m−1 조절하여 관리하는 것이 효과적임을 알 수 있었다.

In this work, electroless Ni-plating on polyethylene terephthalate (PET) ultra-fine fibers surfaces was carried out to improve the electric conductivity of the fiber. The surface properties of PET ultra-fine fibers were characterized using scanning electron microscopy, X-ray diffraction, and contact angle analyses. The electric conductivity of the fibers was measured using a 4-point testing method. The experimental results revealed the presence of island-like nickel clusters on the PET ultra-fine fibers surfaces in the initial plating state, and the electric conductivity of the Ni-plated fibers was enhanced with increasing plating time and thickness of the Ni-layers on the PET ultra-fine fibers.

Ti₂AlN composites are a laminated compounds that posses unique combination of typical ceramic proper- ties and typical metallic(Ti alloy) properties. In this paper, the powder synthesis, SPS sintering, composite characteristics and machinability evaluation were systematically conducted. The random orientation characteristics and good crystalli- zation of the Ti2AlN phase are observed. The electrical and thermal conductivity of Ti2AlN is higher than that of Ti6242 alloy. A machining test was carried out to compare the effect of material properties on micro electrical discharge drilling for Ti2AlN composite and Ti6242 alloy. Also, mixture table as a kind of tables of orthogonal arrays was used to know how parameter is main effective at experimental design. Consequently, hybrid Ti2AlN ceramic composites showed good machining time and electrode wear shape under micro ED-drilling process. This conclusion proves the feasibility in the industrial applications.

The bipolar plate is the most important and most costly component of proton exchange membrane fuel cells. The development of a suitable low density bipolar plate is scientif-cally and technically challenging due to the need to maintain high electrical conductivity and mechanical properties. Here, bipolar plates were developed from different particle sizes of natural and expanded graphite with phenolic resin as a polymeric matrix. It was observed that the particle size of the reinforcement significantlyinfluencesthe mechanical and electri-cal properties of a composite bipolar plate. The composite bipolar plate based on expanded graphite gives the desired mechanical and electrical properties as per the US Department of Energy target, with a bulk density of 1.55 g.cm-3 as compared to that of ~1.87 g.cm-3 for a composite plate based on natural graphite (NG). Although the bulk density of the expanded-graphite-based composite plate is ~20% less than that of the NG-based plate, the I-V perfor-mance of the expanded graphite plate is superior to that of the NG plate as a consequence of the higher conductivity. The expanded graphite plate can thus be used as an electromagnetic interference shielding material.

In this paper, a three dimensional numerical analysis tool was applied to study the PEMFC performance characteristics. The porosity and electrical conductivity of GDL and CL as well as the relative humidity of anode and cathode channel gas were selected as simulation parameters. The porosity of GDL and CL was varied as 0.3, 0.5, and 0.7. The relative humidity of anode and cathode was varied as 0, 20, 40, 60, 80, and 100 percent. The electrical conductivity of GDL and CL was varied as 1, 5, 10, 50, 102, and 104 1/Ω·m. For a constant cell voltage condition, the maximum current density was obtained at GDL porosity of 0.7, anode relative humidity of 100 percent, cathode relative humidity of 60 percent, and electrical conductivity of 104 1/Ω·m for GDL and CL. As the porosity of GDL and CL increases, current density increases because reactant gases diffuse well. As the electrical conductivity of GDL and CL increases, current density increases due to increased electron transfer rate. As anode relative humidity increases, current density increases. Unlike anode, current density increases when cathode relative humidity increases from 0 percent to 60 percent. Then current density decreases when cathode relative humidity increases from 60 percent to 100 percent.

A fabrication method to improve the processability of thermoplastic carbon nanotube (CNT) mat composites was investigated by using in-situ polymerizable and low viscous cyclic butylene terephthalate oligomers. The electrical conductivity of the CNT mat composites strongly depended on the compression pressure, and the trend can be explained in terms of two cases, low and high compression pressure, respectively. High CNT mat content in the CNT mat composites and the surface of the CNT mat composites with fully contacted CNTs was achieved under high compression pressure, and direct contact between four probes and the surface of the CNT mat composites with fully contacted CNTs gave resistance of 2.1Ω. In this study the maximum electrical conductivity of the CNT mat composites, obtained under a maximum applied compression pressure of 27 MPa, was 11 904 S m-1, where the weight fraction of the CNT mat was 36.5%.

Graphene is one of the most promising materials for many applications. It can be used in a variety of applications not only as a reinforcement material for polymer to obtain a combination of desirable mechanical, electrical, thermal, and barrier properties in the resulting nanocomposite but also as a component in energy storage, fuel cells, solar cells, sensors, and batteries. Recent research at Michigan State University has shown that it is possible to exfoliate natural graphite into graphite nanoplatelets composed entirely of stacks of graphene. The size of the platelets can be controlled from less than 10 nm in thickness and diameters of any size from sub-micron to 15 microns or greater. In this study we have investigated the influence of melt compounding processing on the physical properties of a polyamide 6 (PA6) nanocomposite reinforced with exfoliated graphite nanoplatelets (xGnP). The morphology, electrical conductivity, and mechanical properties of xGnP-PA6 nanocomposite were characterized with electrical microscopy, X-ray diffraction, AC impedance, and mechanical properties. It was found that counter rotation (CNR) twins crew processed xGnP/PA6 nanocomposite had similar mechanical properties with co-rotation (CoR) twin screw processed or with CoR conducted with a screw design modified for nanoparticles (MCoR). Microscopy showed that the CNR processed nanocomposite had better xGnP dispersion than the (CoR) twin screw processed and modified screw (MCoR) processed ones. It was also found that the CNR processed nanocomposite at a given xGnP content showed the lowest graphite X-ray diffraction peak at 26.5˚ indicating better xGnP dispersion in the nanocomposite. In addition, it was also found that the electrical conductivity of the CNR processed 12 wt.% xGnP-PA6 nanocomposite is more than ten times higher than the CoR and MCoR processed ones. These results indicate that better dispersion of an xGnP-PA6 nanocomposite is attainable in CNR twins crew processing than conventional CoR processing.

Carbon materials such as graphite and graphene exhibit high electrical conductivity. We examined the electrical conductivity of synthetic and natural graphene powders after the chemical reduction of synthetic and natural graphite oxide from synthetic and natural graphite. The trend of electrical conductivity of both graphene (synthetic and natural) was compared with different graphite materials (synthetic, natural, and expanded) and carbon nanotubes (CNTs) under compression from 0.3 to 60 MPa. We found that synthetic graphene showed a marked increment in electrical conductivity compared to natural graphene. Interestingly, the total increment in electrical conductivity was greater for denser graphite; however, an opposite behavior was observed in nanocarbon materials such as graphene and CNTs, probably due to the differing layer arrangement of nanocarbon materials.

In this study, the effect of Sn and Mg on microstructure and mechanical properties of Cu-Fe-P alloy were investigated by using scanning electron microscope, transmission electron microscope, tensile strength, electrical conductivity, thermal softening, size and distribution of the precipitation phases in order to satisfy characteristic for lead frame material. It was observed that Cu-0.14wt%Fe-0.03wt%P-0.05wt%Si-0.1wt%Zn with Sn and Mg indicates increasing tensile strength compare with PMC90 since Sn restrained the growth of the Fe-P precipitation phase on the matrix. However, the electrical conductivity was decreased by adding addition of Sn and Mg because Sn was dispersed on the matrix and restrained the growth of the Fe-P precipitation. The size of 100 nm Mg3P2 precipitation phase was observed having lattice parameter a:12.01Å such that [111] zone axis. According to the results of the study, the tensile strength and the electrical conductivity satisfied the requirements of lead frame; so, there is the possibility of application as a substitution material for lead frame of Cu alloy.

This study looked at high performance copper-based alloys as LED lead frame materials with higher electrical-conductivity and the maintenance of superior tensile strength. This study investigated the effects on the tensile strength, electrical conductivity, thermal softening, size and distribution of the precipitation phases when Cr was added in Cu-Fe alloy in order to satisfy characteristics for LED Lead Frame material. Strips of the alloys were produced by casting and then properly treated to achieve a thickness of 0.25 mm by hot-rolling, scalping, and cold-rolling; mechanical properties such as tensile strength, hardness and electrical-conductivity were determined and compared. To determine precipitates in alloy that affect hardness and electrical-conductivity, electron microscope testing was also performed. Cr showed the effect of precipitation hardened with a Cr3Si precipitation phase. As a result of this experiment, appropriate aging temperature and time have been determined and we have developed a copper-based alloy with high tensile strength and electrical-conductivity. This alloy has the possibility for use as a substitution material for the LED Lead Frame of Cu alloy.

본 연구는 시중에서 판매되는 고추 역병저항성 대목품종을 이용한 시설내 접목재배시 기존의 실생묘와 비교하여 공급양액의 EC 수준에 따른 고추 접목묘들의 생육과 생리적 반응을 알아보고자 하였다. 접목을 위한 대목으로 '카타구루마', '코네시안 핫', '탄탄'의 3가지 품종을 사용하였고, 대조구로 실생 품종 '녹광' 접수로 이용하였다. 공급양액의 EC 조건에 따른 접목묘와 실생묘의 생육과 생리적 반응 시험을 위해 공급 양액의 EC를 각각 1.5, 3.0, 5.0dS/m로 설정하여 비교시험을 수행하였다. 공급양액의 EC 수준에 따른 생육은 실생묘와 접목묘 모두 EC 수준이 높아질수록 억제되는 경향을 보였다. 접목묘 중 '카타구루마'가 EC 5.0dS/m에서 다른 품종들에 비해서 생육이 상대적으로 양호하였다. 단, EC 조건에 따른 생육은 재배시험 시기에 따라 다소 차이가 있었다. 무기양분의 흡수는 T-N과 P 농도는 EC 수준이 높을수록 증가하였으며, Ca과 Mg은 흡수량이 감소하였다. 광합성 능력은 실생묘는 EC 1.5와 3.0dS/m 수준간에 차이가 없으나, EC 5.0dS/m 수준에서 낮게 나타났다. 접목묘들도 EC 5.0dS/m 수준에서 광합성 능력이 낮아지는 결과를 보였다. SOD 활성도는 EC 수준에 따라 일정한 경향이 나타나지 않았으며, APX 활성도는 EC 5.0dS/m 수준에서 활성도가 높게 나타났다. 추후 더 다양한 대목들을 이용한 비교시험이 필요하며, 저온신장성과 내염성이 강한 대목 품종의 개발을 위한 연구의 필요성이 높다.

Hydrogen production via high high-temperature steam electrolysis consumes less electrical energy than compared to conventional low low-temperature water electrolysis, mainly due to the improved thermodynamics and kinetics at elevated temperaturetemperatures. The elementalElemental powders of Cu, Ni, and YSZ are were used to synthesize high high-temperature electrolysis cathodecathodes, of Ni/YSZ and Cu/YSZ composites, by mechanical alloying. The metallic particles of the composites were uniformly covered with finer YSZ particles. Sub-micron sized pores are were homogeneously dispersed in the Ni/YSZ and Cu/YSZ composites. In this study, The cathode materials were synthesized and their Characterizations properties were evaluated in this study: It was found that the better electric conductivity of the Cu/YSZ composite was measured improved compared tothan that of the Ni/YSZ composite. Slight A slight increase in the resistance can be produced for in a Cu/YSZ cathode by oxidation, but it this is compensated offset for by a favorable thermal expansion coefficient. Therefore, Cu/YSZ cermet can be adequately used as a suitable cathode material of in high high-temperature electrolysis.

제주도는 현무암과 조면암으로부터 기원한 투수성 높은 토양으로 인하여 지표수 유입에 따른 상시하천 발달이 어려워, 용수의 대부분을 지하수에 의존하고 있다. 이에 따른 무분별한 지하수 개발은 지하수위 강하로 이어져, 제주도내 많은 지역에서 지하수 오염과 해수침투 현상이 나타나고 있다. 제주특별자치도는 제주도의 항구적인 지하수자원 보전을 위하여 1994년 이래 일부 지역을 지하수 보전구역으로 지정하였으며, 이 지역내의 모든 지하수 개발은 허가를 받도록 지정한 바 있다. 또한 지하수 수문과 관련된 수리지질 정보 획득을 위하여, 2001년 이래로 제주도 내 해안지역 및 저지대 전체를 대상으로 지하수 관측망을 설치 운영 중이다. 본 연구에서 이러한 지하수 관측망으로부터 얻어진 지하수위, 수온, 전기전도도 등 장기 관측자료를 분석한 결과, 북부 해안지역의 경우 지하수위가 지속적으로 하강하는 것으로 나타났다. 또한 동부 해안지역의 경우는 최근 취수량의 급격한 증가에 따른 해수침투의 영향으로, 대부분의 관측정에서 전기전도도가 높게 나타나며 지속적으로 증가하고 있는 추세로 분석되었다. 이러한 문제점들은 지하수 개발과 관련하여 제주특별자치도의 강력한 통제로 인하여 최근들어 감소하는 추세이지만, 본 연구 결과에 의하면 해안지역의 경우에는 지하수위 하강 및 전기전도도 상승 현상이 지속될 것으로 판단된다.

[ ] was coated with , MgO and respectively by sol-gel method and cured at 900 and . The coated oxides did not react with at but reacted with it to form at . The specimen coated with at formed a dense protecting layer and showed the best oxidation resistance at in air. However, the dense protecting layers did not form in and MgO coated specimens cured even at . MgO coated specimen showed the worst improvement in the oxidation resistance because the reactivity of MgO with was highest. On the other hand, the electrical conductivities were measured in MgO and coated specimens to have TiCx but could not be measured in the coated ones because of the nonconductive dense protected layers.

The microstructure and electrical conductivity of CNTs dispersed nanocomposites depending on the powder processing and CNTs content were demonstrated. The composite powders with homogeneous dispersion of CNTs could be synthesized by a catalytic route for direct formation of CNTs on nano-sized Fe dispersed powders. The sintered nanocomposite using the composite powder with directly synthesized CNTs showed homogeneous microstructure and enhanced elelctrical conductivity. The influence of powder processing on the properties of sintered nanocomposites was discussed by the observed microstructural features.