• Journal of Communications and Networks
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• v.15 no.6
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• pp.569-575
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• 2013

In this paper, we present a photonic approach for generating highly stable coherent sub-terahertz (THz) signals for wireless communications. As proof-of-concept we transmit data at 100 GHz carrier frequency using on-off keying modulation and heterodyne detection. The sub-THz carrier signals are generated by photo-mixing two optical carrier signals at different frequencies, extracted from an optical frequency comb. We introduce a novel system to stabilize the phase of the optical carrier signals. Error-free transmission is successfully achieved up to a bit rate of 8.5 Gbit/s at 100 GHz.

• ETRI Journal
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• v.27 no.3
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• pp.319-325
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• 2005

In this paper the effect of temperature on the electrical properties of organic semiconductor disperse orange dye 25 (OD) have been examined. Thin films of OD have been deposited on $In_{2}O_{3}$ substrates using a centrifugal machine. DC current-voltage (I-V) characteristics of the fabricated devices $(Al/OD/In_{2}O_{3)$ have been evaluated at varying temperatures ranging from 40 to $60^{\circ}C$. A rectification behavior in these devices has been observed such that the rectifying ratio increases as a function of temperature. I-V characteristics observed in $Al/OD/In_{2}O_{3)$ devices have been classified as low temperature $({\leq} 50^{\circ}C)$ and high temperature characteristics (approximately $60^{\circ}C$). Low temperature characteristics have been explained on the basis of the charge transport mechanism associated with free carriers available in OD, whereas high temperature characteristics have been explained on the basis of the trapped space-charge-limited current. Different electrical parameters such as traps factor, free carrier density, trapped carrier density, trap density of states, and effective mobility have been determined from the observed temperature dependent I-V characteristics. It has been shown that the traps factor, effective mobility, and free carrier density increase with increasing values of temperature, whilst no significant change has been observed in the trap density of states.

• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.319-323
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• 1973

The state of carrier-free silver-111 has been studied by applying filtration method. The studies involved that the effects of pH and concentration of silver-111 in aqueous solution have been determined with membrane filters. The present studies revealed that the retainment of silver-111 on membrane filters followed Freundlish adsorption isotherm, and the adsorbed state of silver-111 was present in the form of AgOH. Also it was supposed that the formation of the non-adsorbed hydroxide of$Ag(OH)_{2}-$ may prohibit the existance of AgOH at higher pH, and it seems to be valid that the carrier-free silver-111 in aqueous solution exists in$Ag^+$state.

• Journal of Pharmaceutical Investigation
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• v.40 no.6
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• pp.373-378
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• 2010

In order to develop a topical preparation which has a high occlusive property with skin moisturization, nano-structured lipid carrier (NLC) systems along with solid lipid nanoparticle (SLN) were designed. Various NLC dispersions were successfully formulated with Compritol 888 ATO as a solid lipid, Labrafil M 1944 CS as an oil, and Tween 80 as a surfactant. The increase of oil content (5 to 50%) led to the decrease in the occlusion factor in the order of SLN > NLC-5 > NLC-15 = NLC-30 > NLC-50. Particle size of lipid particulates was in the range of 100 to 160 nm. NLC-based carbogels were prepared by the employment of humectants such as urea, glycerin, and Tinocare GL to carbomer gel. NLC-30 gel formulations containing 4 or 8 % of lipid particles showed improved occlusive effect in vitro, compared to NLC-free gel base. Even though NLC-free gel base revealed comparable occlusion effect by itself, the occlusion factor of 4 % NLC-30 gel was about 2-fold higher than that of NLC-free gel base.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.263-269
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• 2021

The carrier-based differential global navigation satellite system (CD-GNSS) has been garnering significant attention as a promising technology for unmanned vehicles for its high accuracy. The CD-GNSS systems to be used for safety-critical applications should provide a certain level of integrity. The integrity of these systems must be analyzed under various conditions, including fault-free and satellite fault conditions. The systems should be able to detect the faults that can cause large biases on the user position errors and quantify the integrity risk by computing the protection level (PL) to protect the user against the faults that are left undetected. Prior work has derived and investigated the PL for the fault-free condition. In this study, the integrity of the CD-GNSS system under the fault condition is analyzed. The position errors caused by the satellite's fault are compared with the fault-free PL (PL_H0) to verify whether the integrity requirement can be met without computing the PLs for the fault conditions. The simulations are conducted by assuming the ephemeris fault, and the position errors are evaluated by changing the size of the ephemeris faults that missed detection. It was confirmed that the existing fault monitors do not guarantee that the position error under the fault condition does not exceed the PL_H0. Further, the impact of the faults on the position errors is discussed.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.344-352
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• 2000

Purpose: Re-188-Hydroxyethylidene diphosphonate (HEDP) is a new cost-effective agent for systemic radioisotope therapy of metastatic bone pain. We investigated the influence of carrier for labeling and biodistribution of Re-188-HEDP using HEDP kit with or without carrier ($KReO_4$). Materials and Methods: The kits (HEDP 15 mg, gentisic acid 4 mg and $SnCl_2.2H_2O_2$ 4.5 mg) with or without carrier ($KReO_4$ 0.1 mg) were labeled with Re-188 solution, made available from an in-house generator by boiling for 15 min. We compared the labeling efficiency and stability of carrier-added and carrier-free preparations of Re-188-HEDP Biodistribution and imaging studies of each preparation were performed in ICR mice ($1.85{\sim}3.7MBq/0.1ml$) and SD rats ($74.1{\sim}85.2MBq/0.5ml$). Results: The carrier-added preparation showed high labeling efficiency (95% at pH 5) and high stability in serum (88%, 3 hr). However, the carrier-free preparation showed low labeling efficiency (59% at pH 5) and low stability (43%, 3 hr). The carrier-added preparation showed high uptake in bone and low uptake in stomach and kidneys. However, the carrier-free preparation showed lower uptake in bone and higher uptake in both stomach and kidneys, which is supposed to be due to released perrhenate. The carrier-added preparation also showed better images with higher skeletal accumulation, lower uptake in other organs and lower soft tissue uptake than the carrier-free preparation. Conclusion: The results of these studies clearly demonstrate that addition of carrier perrhenate is required for high labeling efficiency, stability, bone uptake and good image quality of Re-188-HEDP.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.583-592
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• 2005

The turbulent free surface flow around a self-propelled KRISO 138K LNG Carrier is numerically simulated using the finite volume based multi-block RANS code, WAVIS developed at HRISO. The realizable k-$\varepsilon$ turbulence model with a wail function is employed for the turbulence closure. The free surface is captured with the Level-Set method and body forces are used to model the effects of a propeller without resolving the detail blade flow. In order to obtain an accurate free surface solution and stable convergence, the computations are executed with a proper fine grid refinement around the free surface and with an adoption of implicit discretization scheme for the Level-Set formulation. The computed velocity vectors at the several stations and wave patterns show a good agreement with the experimental results measured at the KRISO towing tank.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.5
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• pp.24-29
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• 1976

In the phase locked AM signal detection, phase locked loop is used to extract a synchronous carrier from an input AM signal. Under the assumption that input noise is white Gaussian and free-running frequency of voltage controlled oscillator is the same that of an input carrier, operational behaviours of phase locked loop is analyzed and signal to noise ratio of the detection is derived quentitatively. The results show that the phase locked AM signal detection method offers a higher degree of noise mmunity than conventional AM signal detections.

• Journal of the Korean Ceramic Society
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• v.37 no.7
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• pp.686-692
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• 2000

Tin-doped In2O3 (ITO) films were fabricated using a d.c. magnetron reactive sputteirng of a In-10 wt% Sn alloy target in an Ar and O2 gas mixture. To understand the behavior of the carrier mobility in ITO films with O2 partial pressure, the resistivity, carrier concentration and mobility, film density, and intrinsic stress in the films were measured with O2 partial pressure. It was found experimentally that the carrier mobility increased rapidly as the film density increased. In the ITO film with the density close to theoretical one, the mean free path was the same as the columnar diameter. This indicated that the mobility in ITO films was strongly influenced by the crystall size. However, in the case where the film density was smaller than a theoretical density, the mean free paths were also smaller the columnar diameter. It was analyzed that the electron scattering at pores and holes within the crystalline was the major obstacle for electron conduction in ITO films. The measurement of intrinsic stress in ITO films also made it clear that the density of ITO films was controlled by the bombardment of oxygen neutrals on the growing film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.947-950
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• 2001

We report the characteristics of organic light emitting diodes (OLEDS) by controlling the carrier mobility according to the crystalline of Iron(II) Phthalocyanine(Fe-Pc) and metal-free Phthalocyanine (H$_2$-Pc). In order to change the recombination zone, we controlled the hole mobility by changing the crystal structures of Fe-Pc and H$_2$-Pc. OLEDs were constructed with ITO/Fe-Pc/triphenyl-diamine (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq$_3$)/Al and ITO/H$_2$-Pc/triphenyl-diamine (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq$_3$)/Al. The electroluminescent properties were changed according to the heat-treatments of Fe-Pc and H$_2$-Pc. We observed that the recombination zone and the carrier mobility were changed as the higher occupied molecular orbital levels of Fe-Pc and H$_2$-Pc decreased.