• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.575-575
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• 2012

Synthesis of novel two dimensional materials has gained tremendous attention recently as they are considered as alternative materials for replacing graphene that suffers from a lack of bandgap, a property that is essential for many applications. Single layer molybdenum disulfide ($MoS_2$) has a direct bandgap (1.8eV) that is promising for use in next-generation optoelectronics and energy harvesting devices. We have successfully grown high quality single layer $MoS_2$ by a facile vapor-solid transport route. As-grown single layer $MoS_2$ was carefully characterized by using X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy and electrical transport measurement. The results indicate that a high quality single layer $MoS_2$ can be successfully grown on silicon substrate. This may open up great opportunities for the exploration of novel nanoelectronic devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.9
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• pp.781-785
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• 2009

We have fabricated simple triple-layer blue-emitting phosphorescent organic light emitting diodes (OLEDs) using different thicknesses (25 and 55 nm) of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) electron transport layers. 1,1-bis[4-bis (4-methylphenyl)- aminophenyllcyclohexane (TAPC), bis[(4,6-di-fluorophenyl)-pyridinate-$N,C^{2'}$]picolinate (FIrpic) and N,N' -dicarbazolyl-3,5-benzene (mCP) were used as hole transport, blue guest and host materials, respectively. The driving voltage, electroluminescence (EL) efficiency and emission characteristics of devices were investigated. The maximum EL efficiency was 20 cd/A in the device with 55 nm BCP layer, which efficiency was about 33% higher than the device with 25 nm BCP layer. The higher efficiency in the 55 nm BCP device resulted from the enhanced electron-hole balance. In the EL spectrum of blue phosphorescent OLED with BCP layer, the relative intensity between 470 and 500 nm peaks was related to the location of emission zone.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.8
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• pp.499-509
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• 2014

In this paper, we propose that a FDL(Freeze DeadLine) Algorithm to solve handover problems in heterogeneous wireless networks. Many previous studies concentrated on low level layer to solve handover problems. In this paper, however, we concentrate on high level handover problems such as network layer and transport layer. We analyze handover's problems of transport layer in Heterogeneous wireless network, propose the FLD algorithm for better performance than others studies. The Proposed method is analyzed by theoretical frames and we verify that the propose method using the NS-2(Network Simulation - 2).

• Journal of Plant Biology
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• v.35 no.2
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• pp.143-153
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• 1992

Nectar secretion from extrafloral nectary cells of Prunus yedoensis was examined by light and electron microscopy. Nectaries were composed of two or three layers of secretory cells and one layer of subsectretory cells. Vascular bundles in the petioles were connected to those of the subsectretory cell layer. Secretory cells had a number of mitochondria with poorly developed cristae. Plastids had little thylakoids and small vesicles, about 0.2 to 0.3 mm in diameter; however, no plastids had starch grains. Calcium oxalate crystals and plasmodesmata were frequently observed in the subsectretory and secretory cells, respectively. And nectar substances were observed in phloem of petiole, subsectretory, and secretory cells of the secretory gland. These results suggested that the nectar moved by symplastic transport through the plasmodesmata. On the other hand, the nectar droplets were observed in the secretory cell walls. in the cuticular layer just beyond of the former, and on the outer surface of the cuticular layer: such observations indicated that a apoplastic movement was involved in the final step of the nectar secretion. Cellular components related to the nectar transport, such as plasma membrane, cell wall and cuticle were not destroyed but intact: it was interpreted as a eccrine secretion.retion.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.665-667
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• 2004

In previous studies, charged mosaic membranes having two different fixed charges in the membrane matrix indicated unique transport behavior such as preferential material transport. In this study, the composite charged mosaic membrane endurable to mechanical pressure in practical application was investigated from the same aspect of solute and solvent transport as before. Lp and ${\omega}$ estimated by taking account of active layer thickness were satisfactorily consistent with those in mosaic membrane without reinforcement. On the other hand, the reflection coefficient s indicated the negative value that suggests preferential material transport.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.710-714
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• 1998

Organic electroluminescence devices (ELD) with hetero-junction structure were fabricated utilizing poly(p-phenylne vinylene) (PPV) as emitting layer and electron transport layer (ETL). 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) was used as an electron transport agent. Copolymers with stilbene type comonomers, such as poly(styrene-co-PVTS), poly(styrene-co-MeO-PVTS) and poly(styrene-co-MeO-ST) were synthesized to be used as a matrix polymer to disperse electron transport agent (PBD). Among the hetero-junction EL devices fabricated with the above materials, the device with poly(styrene-co-PVTS) as matrix polymer for ETL gave the highest luminance ($120.7cd/m^2$, 13 V). EL devices made with poly(styrene-co-MeO-PVTS) or poly(styrene-co-MeO-ST) matrix exhibited lower luminance than the one with polystyrene matrix and the single layer EL (ITO/PPV/Mg) device.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04a
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• pp.76-77
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• 2009

In this paper, We have studied Electron Transport Layer(ETL) in the New Organics applied to Red phosphorescent organic light-emitting devices. The structure of ITO/2-TNATA(15nm)/CBP;$Ir(piq)_3$/DPVBi(30nm)/New ETL(60nm)/LiF(0.5nm)/Al(100nm) has been used, measured changing doping concentration of EML. The results of OLED turn-on voltage at 2.2V, and Maximum Luminance at 2.8V was $1000cd/m^2$. This high luminance at low voltage results from a high electron. conduction of the new electron transport layer.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.733-740
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• 2005

In this paper, we propose an approach to transport layer mobility support leveraging the SCTP extension dubbed dynamic address reconfiguration in IPv6 networks. Timing issues related to the end-to-end address management, and a novel error recovery mechanism associated with a handover are discussed. The proposed error recovery mechanism is analyzed and compared to that of the plain SCTP to show that it reduces the handover latency and error recovery time.

• Proceedings of the KIEE Conference
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• summer
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• pp.1133-1135
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• 2004

Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of important parameters in high-temperature superconducting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and ac loss. In this paper, the transport current and magnetic field distributions at conducting layers were investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer. The transport current distribution due to the pitch length and winding direction was improved in case of HTSC power cable with shield layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.116-119
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• 1997

In this paper A double-layer organic electroluminescent(EL) device was fabricated using a TPD(N,N'-dipheny] -N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4.4'-diamine: aromatic diamine), as a hole-transport material and tris (8-hydroxy quinolinate) aluminum(Alq$_3$) as a an emiting material and its performance characteristics were investigated. structure of devices is ITO/TPD/Alq$_3$/Al. we have fabricated hole transport layer of two types. Doping material of Hole Transport material is Poly(methyl methacrylate)(PMMA) and PEI(Poly-Ether-Imide). Carrier injection from the electrodes to the doped PMMA and PEI layer through the dopants and concomitant electroluminescence from Alq$_3$were observed. Green emission with luminance of 40cd/m$^2$was achieved at a drive voltage of 30V