• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.429-433
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• 2003

We try to analyse the localization phenomenon of a lightwave in random media by means of considering the solution of the propagation equation on a transmission line in which the propagation constants are randomly distributed. Lightwave localization is generated at the turning point where the solution is changed suddenly from an increase to a decrease. First, in order to investigate the changing process of the solution, we have derived the approximated one-dimensional Schrodinger equation from the two-dimensional wave equation by using the Brags condition. Considering the many types of solutions of the wave equation, we have investigated the conditions that allow the solutions to exist. Also, we have investigated the relationships between the localization of the solution and the variation of the propagation constant. In case of the exponential solution, we know that the permittivity $\varepsilon$=(0,0$\varepsilon$$_{0}$) is a very important parameter to influence the phase of the lightwave and to generate the localization.

• Journal of Biomedical Engineering Research
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• v.22 no.3
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• pp.249-257
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• 2001

The voluntary contracted EMG signal of spinal cord injured patients is very small because the information from central nervous system is not sufficiently transmitted to $\alpha$ motor neuron or muscle fiber. Therefore the acquisited EMG signal from needle or surface electrodes can not be identified obvious voluntary contraction pattern by muscle movement. In this paper we propose the extraction technique of voluntary muscle contraction and relaxation pattern from EMG signal of spinal cord injured patient whose EMG signal is composed of the linear sum of mo색 unit action potentials with two noise sources, additive noise assumed to be white Gaussian noise and high frequency discharge assumed to be not motor unit action potential but impulsive noise. In order to eliminate impulsive noise and additive noise from voluntary contracted EMG signal, we use the FatBear filter which is a nonarithmetic piecewise constant filter, and multiscale nonlinear wavelet denoising processing, respectively. The proposed technique is applied to the EMG signal acquisited from transverse myelitis patients to extract voluntary muscle contraction pattern.

• International Journal of Concrete Structures and Materials
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• v.9 no.2
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• pp.241-254
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• 2015

A lot of reinforced concrete (RC) structures in Syria went out of service after a few years of construction. This was mainly due to reinforcement corrosion or chemical attack on concrete. The use of blended cements is growing rapidly in the construction industry due to economical, ecological and technical benefits. Syria is relatively rich in scoria. In the study, mortar/concrete specimens were produced with seven types of cement: one plain Portland cement (control) and six blended cements with replacement levels ranging from 10 to 35 %. Rapid chloride penetration test was carried in accordance with ASTM C 1202 after two curing times of 28 and 90 days. The effect on the resistance of concrete against damage caused by corrosion of the embedded steel has been investigated using an accelerated corrosion test by impressing a constant anodic potential. The variation of current with time and time to failure of RC specimens were determined at 28 and 90 days curing. In addition, effects of aggressive acidic environments on mortars were investigated through 100 days of exposure to 5 % $H_2SO_4$, 10 % HCl, 5 % $HNO_3$ and 10 % $CH_3COOH$ solutions. Evaluation of sulfate resistance of mortars was also performed by immersing in 5 % $Na_2SO_4$ solution for 52 weeks. Test results reveal that the resistance to chloride penetration of concrete improves substantially with the increase of replacement level, and the concretes containing scoria based-blended cements, especially CEM II/B-P, exhibited corrosion initiation periods several times longer than the control mix. Further, an increase in scoria addition improves the acid resistance of mortar, especially in the early days of exposure, whereas after a long period of continuous exposure all specimens show the same behavior against the acid attack. According to results of sulfate resistance, CEM II/B-P can be used instead of SRPC in sulfate-bearing environments.

• Archives of Reconstructive Microsurgery
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• v.8 no.1
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• pp.15-21
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• 1999

Soft tissue defect on heel area of the foot present difficult problems particularly because of anatomic property of plantar surface of the foot. There is a paucity of available local tissue in the foot for coverage. In addition to having little expandable tissue, the foot's plantar surface has a unique structure, making its replacement especially challenging. Plantar skin is attached to the underlying bone by fibrous septa, preventing shear of the soft-tissue surfaces from the underlying skeleton. Plantar surface of foot is in constant contact with the environment. Protective sensibility also would be maintained or restored in the ideal reconstruction. So the ideal flap for reconstruction of the heel should include thin, durable hairless skin with potential for reinnervation. The aim of this article is to present a clinical experience of free lateral arm neurosensory flap for reconstruction of the heel. From March 1995 to December 1997, a total 16 lateral arm free flaps were performed to soft tissue defects on the weight-bearing area of the hindfoot. we used tibial nerve as recepient nerve in 11 and calcaneal branch of tibial nerve in 5 for restoration of sensibility of flap. All cases survived completely. A static two-point discrimination of 14 to 34mm was detected in the flap. Radial nerve palsy which was caused by hematoma in donor site occured in one case, but recorverd in 3 weeks later completely. In conclusion, the lateral arm free flaps are versatile, reliable and sensible cutaneous flap and especially indicated for soft tissue defect on plantar surface of the hindfoot which are not good indications for other better-known flaps.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.8-15
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• 2018

A portion of the veterinary antibiotics administrated to livestock are generally excreted via feces and urine. Tetracyclines and tylosin have a greater priority of environmental risk in Korea based on the consumption and the potential to reach soil and water environment. The antibiotics in animal byproducts need to be reduced or eliminated before they are applied to agricultural lands through composting or other agricultural practices. The objective of the study was to investigate the effect of aeration on degradation of antibiotics during storage of swine slurry. Two antibiotics, tetracycline (TC) and tylosin (TYL), were detected from the swine slurry used in the study. One hour aeration per day for 62 days reduced TC concentration from 199 to $43ng\;L^{-1}$ compared with $104ng\;L^{-1}$ without aeration. Aeration for three and six hours decreased TC level to 30 and $23ng\;L^{-1}$, respectively. The dissipation of TC was fitted with a first-order kinetic model. Aeration for 1, 3, and 6 hours every day increased the first-order rate constant, k, from $0.011day^{-1}$ under anaerobic condition to 0.022, 0.026, and $0.037day^{-1}$, respectively. For TYL, aeration during storage of swine slurry enhanced k from $0.0074day^{-1}$ to 0.014, 0.018, and $0.031day^{-1}$ for 1, 3, and 6 hours per day, respectively. For liquid swine slurry, biotic processes can be more effective for dissipation of antibiotics than abiotic processes because of low organic matter and high water content. These results suggest that aeration can increase the degradation rate of antibiotics during storage of swine slurry.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.453-458
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• 1994

$(Ba_{0.5}Sr_{0.5)/TiO_3$(BST) thin films were prepared for the application of 256 Mb DRAM by RF magnetron sputtering. The crystallinity of BST thin films increased with increasing deposition tempera lure. The composition of thin films was $(Ba_{0.48}Sr_{0.48)/TiO_{2.93}$ Pt/Ti barrier layer suppressed the diffusion of Si into BST layer. The films showed a dielectric constant of 320 and a dissipation factor of 0.022 at 100 kHz. the change of capacitance of the films with applied voltage was small, showing paraelectric property. The charge storage density and leakage current density were 40fC/$\mu \textrm{m}^{2}$ and 0.8$\mu A/\textrm{cm}^2$, respectively at a field of 0.15 MV/cm. The BST films obtained by RF magnetron sputtering appeared to be potential thin film capacitors for 256 Mb DRAM application.

• Korean Journal of Materials Research
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• v.19 no.10
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• pp.550-554
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• 2009

Unreported dielectrics based on the binary system of MgO-SiO$_2$ were investigated as potential candidates for microwave dielectric applications, particularly those demanding a high fired density and high quality factors. Extensive dielectric compositions having different molar ratios of MgO to SiO$_2$, such as 2:1, 3:1, 4:1, and 5:1, were prepared by conventional solid state reactions between MgO and SiO$_2$. 1 mol% of V$_2$O$_5$ was added to aid sintering for improved densification. The dielectric compositions were found to consist of two distinguishable phases of Mg$_2$SiO$_4$ and MgO beyond the 2:1 compositional ratio, which determined the final physical and dielectric properties of the corresponding composite samples. The increase of the ratio of MgO to SiO$_2$ tended to improve fired density and quality factor (Q) without increasing grain size. As a promising composition, the 5MgO.SiO$_2$ sample sintered at 1400 $^{\circ}C$ exhibited a low dielectric constant of 7.9 and a high Q $\times$ f (frequency) value of $\sim$99,600 at 13.7 GHz.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.3
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• pp.203-212
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• 2010

In this paper, we present an analytical model for the first eigen energy level ($E_0$) of the carriers in the inversion layer in present generation MOSFETs, having ultrathin gate oxides and high substrate doping concentrations. Commonly used approaches to evaluate $E_0$ make either or both of the following two assumptions: one is that the barrier height at the oxide-semiconductor interface is infinite (with the consequence that the wave function at this interface is forced to zero), while the other is the triangular potential well approximation within the semiconductor (resulting in a constant electric field throughout the semiconductor, equal to the surface electric field). Obviously, both these assumptions are wrong, however, in order to correctly account for these two effects, one needs to solve Schrodinger and Poisson equations simultaneously, with the approach turning numerical and computationally intensive. In this work, we have derived a closed-form analytical expression for $E_0$, with due considerations for both the assumptions mentioned above. In order to account for the finite barrier height at the oxide-semiconductor interface, we have used the asymptotic approximations of the Airy function integrals to find the wave functions at the oxide and the semiconductor. Then, by applying the boundary condition at the oxide-semiconductor interface, we developed the model for $E_0$. With regard to the second assumption, we proposed the inclusion of a fitting parameter in the wellknown effective electric field model. The results matched very well with those obtained from Li's model. Another unique contribution of this work is to explicitly account for the finite oxide-semiconductor barrier height, which none of the reported works considered.

• Polymer(Korea)
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• v.34 no.6
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• pp.527-533
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• 2010

The pioglitazone loaded poly(lactide-co-glycolide)(PLGA) nanospheres were prepared by emulsion-evaporation method and optimized for particle size and entrapment efficiency. The optimized particles were 125~170 nm in size with narrow size distribution and showed above 85% entrapment efficiency at 30% of pioglitazone loading when prepared with 3% w/v of poly(vinyl alcohol) (PVA) as a surfactant. These particulate carriers exhibited a controlled in vitro release of pioglitazone for 40 days at a nearly constant rate. The pioglitazone loaded PLGA nanospheres were not only effective to reduce the blood sugar level of diabetic rats but also non-toxic for the animal body, in particular for sensitive organs like kidney, liver, heart, lung and spleen. These results indicate that PLGA nanospheres have a great potential for oral delivery of pioglitazone.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.42-42
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• 2008

Considerable attention has been focused on the applications of flexible liquid crystal (LC)-based displays because of their many potential advantages, such as portability, durability, light weight, thin packaging, flexibility, and low power consumption. To develop flexible LCDs that are capable of delivering high-quality moving images, like conventional glass-substrate LCDs, the LC device structure must have a stable alignment layer of LC molecules, concurrently support uniform cell gaps, and tightly bind two flexible substrates under external tension. However, stable LC molecular alignment has not been achieved because of the layerless LC alignment, and consequently high-quality images cannot be guaranteed. To solve these critical problems, we have proposed a PDMS pixel-wall based bonding method via the IB irradiation was developed for fasten the two substrates together strongly and maintain uniform cell gaps. The effect of the IB irradiation on PDMS with PI surface was also evaluated by side structure configuration and a result of x-ray photoelectron spectroscopic analysis of PDMS interlayer as a function of binder with substrates. large number of PDMS pixel-walls are tightly fastened to the surface of each flexible substrate and could maintain a constant cell gap between the LC molecules without using any other epoxy or polymer. To enhance the electro-optical performance of the LC device, we applied an alignment method that creates pretilt angle on the PI surface via ion beam irradiation. Using this approach, our flexible LCDs have a contrast ratio of 132:1 and a response time of about 15 ms, resulting in highly reliable electro-optical performance in the bent state, comparable to that of glass-substrate LCDs.