• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.243.1-243.1
• /
• 2016

Recently, many groups have attempted to fabricate 3-dimensional (3D) structures of GaN such as pyramids, rods, stripes and annulars. Since quantum structures on non-polar and semi-polar planes of 3D structures have less influence of internal electric filed, multi quantum wells (MQWs) formed on those planes have high quantum efficiency. Especially, pyramidal and annular structures consist of various crystal planes with different emission wavelength, providing a possibillity of phosphor-free white light emtting diodes (WLEDs).[1] However, it still has problem to obtain high color rendering index (CRI) number because of narrow-band emission and poor indium composition caused by the formation of few number of facets during metal-organic chemical vapor deposition growth.[2] If we can fabricate 3D structure having more various facets, we can make broad-band emittied WLEDs and improve CRI number. In this study, we suggest a simple method to fabricate 3D structures having various facet and containing high indium composition by means of a combination of metal-organic chemical vapor deposition and wet chemical etching techniques.

• Journal of Microbiology and Biotechnology
• /
• 제25권5호
• /
• pp.629-636
• /
• 2015

Chemical investigation of the actinobacterial isolate Pseudonocardia endophytica VUK-10 has led to the segregation of two known bioactive compounds, namely 4-(2-acetamidoethyl) phenyl acetate and 4-((1, 4-dioxooctahydropyrrolo [1, 2-a] pyrazin-3-yl) methyl) phenyl acetate. The strain was isolated from a sediment sample of the Nizampatnam mangrove ecosystem, south coastal Andhra Pradesh, India. The chemical structure of the active compounds was established on the basis of spectroscopic analysis, including ¹H NMR and ¹³C NMR spectroscopies, FTIR, and EIMS. The antimicrobial and cytotoxic activities of the bioactive compounds produced by the strain were tested against opportunistic and pathogenic bacteria and fungi and on MDA-MB-231, OAW, HeLa, and MCF-7 cell lines. The compounds exhibited antimicrobial activities against gram-positive and gram-negative bacteria and fungi and also showed potent cytotoxic activity against MDA-MB-231, OAW, HeLa, and MCF-7 cell lines. This is the first example for this class of bioactive compounds isolated from Pseudonocardia of mangrove origin.

• 한국환경과학회지
• /
• 제24권10호
• /
• pp.1253-1264
• /
• 2015

This study assessed the fertilizing value of struvite deposit recovered from swine wastewater in cultivating Chinese cabbage. Struvite deposit was compared with commercial fertilizers: complex, organic and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test obviously presented that the struvite deposit more facilitated the growth of Chinese cabbage than organic and compost fertilizers even though complex fertilizer was the most effective in growing Chinese cabbage. It was revealed that the growth rate of Chinese cabbage was simultaneously controlled by phosphorus (P) and potassium (K). Also, the nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Specifically, P was the most abundant component in the vegetable tissue of struvite pot. Meanwhile, the utilization of struvite as a fertilizer led to the lower accumulation of chromium ($Cr^{6+}$) than other pots, except for compost fertilizer pots, and no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the Chinese cabbage. The experimental results proved that the optimum struvite dosage for the cultivation of Chinese cabbage was 2.0 g struvite/kg soil. On the basis of these findings, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for Chinese cabbage cultivation.

• 한국세라믹학회지
• /
• 제33권12호
• /
• pp.1365-1372
• /
• 1996

투광성이 좋고 dimer의 형성이 억제되는 유기염료의 기저체를 얻기 위해 Ormosil(organically modified silicate)제조시에 출발물질 및 촉매의 조성을 변화시켰으며 이 각각의 조성에 따른 미세구조의 변화가 광학특성에 미치는 영향에 대한 연구가 수행되었다. 광학적 응용이 가능한 Ormosil의 TEOS/PDMS 비는 90/10이었으며 겔의 미세구조 변화는 HCI/TEOS의 비를 조절하여 달성하였다. 이 HCI/TEOS의 비가 증가될수록 그 복합체의 기공은 커졌으며, 기공률은 증가되었다. 또한 이 비의 증가에 따라 투광성이 감소되었다. 이러한 특성변화를 가지는 기저체에 염료인 Rhodamice 6G perchlorate(Rh6Gp)를 첨가하면 HCI/TEOS의 비가 증가할수록 monomer에 대한 dimer 피크의 강도가 증가되었다.

• 한국전기전자재료학회논문지
• /
• 제15권7호
• /
• pp.615-620
• /
• 2002

In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidise (GOx) forms a coordinate bond with the polymers backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized enzyme electrodes by electropolymerization added some organic solvent, such as ethanol and tetrahydrofuran (THF). The formative seeds of film growth was delayed by adding ethanol. The delay was induced by radical transfer between ethanol and pyrrole monomer. The radical transfer reactions shared the contribution of dopants between electrolyte anion and GOx polyanion. This led to increase amount of immobilized the enzyme in PPy. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased.

• 한국전기전자재료학회논문지
• /
• 제19권11호
• /
• pp.1037-1043
• /
• 2006

We report the enhancement of hole injection using ozone-treated Ag nanodots dispersed on indium tin oxide anode in $Ir(ppy)_3-doped$ phosphorescent OLED. Phosphorescent OLED fabricated on Ag nanodots dispersed ITO anode showed a lower turn on voltage and higher luminescence than those of OLEDS prepared commercial ITO anode. Synchrotron x-ray scattering examination results showed that the Ag nanodots dispersed on ITO anode is amorphous structure due to low deposition temperature. It was thought that decrease of the energy barrier height as Ag nanodots changed to $AgO_x$ nanodots by surface treatment using ozone for 10 min led to enhancement of hole injection in phosphorescent OLED. Futhermore, efficient hole injection can be explained by increase of contact region between anode material and organic material through introduction of $Ag_2O$ nanodots.

• 상하수도학회지
• /
• 제30권5호
• /
• pp.545-551
• /
• 2016

This study compares characteristic of membrane fouling in MBR-RO systems. In lab. scale MBRs test, MBRs were operated at different Flux(10, 20, 30 & 40 LMH) and temperature(10, 15, 20, 25 & $30^{\circ}C$). The results show that MBR permeate was measured lower amounts of organic substances in Higher flux and lower temperature and led to lower RO fouling rates. The main cause was that due to cake fouling formed on membrane surfaces in MBRs. Under both cases, Cake layer of membrane surfaces formed in MBRs removed RO fouling factors, polysaccharide and protein, because of cake layer attached on membrane surfaces greater amounts of organic substances. This study implies that optimization of MBR with operating conditions is a crucial strategy to RO membrane fouling control.

• 한국지반환경공학회 논문집
• /
• 제8권4호
• /
• pp.41-45
• /
• 2007

바이오필터의 운전에 있어 큰 표면적, 높은 한계 역압력을 가지고 있는 충진 담체의 선택은 매우 중요하다. 본 연구의 목적은 황산화 세균을 분리하고 분리된 황산화 세균과 바이오필터를 이용해 담체 종류에 따른 황화수소의 제거특성을 조사하는 것이며 연구결과는 다음과 같다. 1) 전남 화순의 폐탄광 폐수에서 Thiobacillus sp. IW.를 분리하였다. 2) 다양한 담체를 이용해 유입농도, 공간속도에 따른 바이오필터의 황화수소 제거특성 및 압력손실 변화 살펴본 결과 무기성 담체가 유기성 담체에 비해 우수한 성능을 나타내었다. 3) 무기성 담체 중에서는 섬유상, PU 담체가 다른 담체에 비해 우수한 성능을 나타내었다.

• 한국전기전자재료학회논문지
• /
• 제17권11호
• /
• pp.1192-1198
• /
• 2004

Hole transporting polymer(poly［N-(p-diphenylamine)phenylmethacrylamide］, PDPMA) was doped with nile red dye at various concentrations to study the influence of doping on the energy transfer during light emitting processes. Organic LEDs composed of ITO/blend(PDPMA -nile red)/ Alq$_3$/Al as well as thin films of blend(PDPMA -nile red)/ Alq$_3$ were manufactured for investigating photoluminescence, electroluminescence, and current-voltage characteristics. Atomic Force Microscopy was also used to observe surface morphology of the blend films. It was found that such doping. significantly influences the efficiency of the energy transfer from the Alq$_3$ layer to blended layer and the optical/electrical properties could be optimized by choosing the right concentration of the dye molecule. The results also showed a interesting correlation with the morphological aspect, i.e. the optimum luminescence at the concentration with the least surface roughness. When the concentration of nile red was 0.8 wt%, the maximum energy transfer could be achieved.

• 한국유기농업학회지
• /
• 제19권spc호
• /
• pp.203-205
• /
• 2011

Investigation on oriental melon was carried out for 30 minutes starting at 7 PM every day from March 21 to May 24 to find out the effect of light emitting diode on seedling quality, grafting, growth and flowering of oriental melon. According to the result of the investigation, plant height was longer in Blue, Infrared, Red+Blue and Red treatment and leaf number was higher in Blue, Red+Blue and Infrared treatment than those of control. No big difference was identified between control and Yellow, Green, Ultraviolet treatments. Grafting rate was high in Green, Red+Blue and Green treatment. The number of flower every week in control was nine, the number was almost 1 higher in White and Ultraviolet A treatments, but it was 1 to 4 lower in the rest of treatments. The number of female flowers of control was 10, however, it was 21 in Infrared treatment, 17 in White, 15 in Ultraviolet, 13 in Red+lnfrared, 12 in Blue and Red+Blue, 11 in Yellow and 8 in Green.