• Journal of the Korean Society of Safety
• /
• v.21 no.4 s.76
• /
• pp.13-18
• /
• 2006

In spite of frequent defect in industrial boilers, life assessment or diagnostic method for them has not been actively studied. In this research, SS400 carbon steel used in industrial boilers is simulated with artificial aging heat treatment. To do qualitative life assessment, differences in micro-structures and hardness of SS400 by the degradation time are studied. In addition, variation in material properties by aging was observed with the tensile test at room temperature and $179^{\circ}C$ and changes in ductile to brittle transition temperature was observed with the charpy impact test performed at several test temperature.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.258-258
• /
• 2006

Electrospun fibers of poly(vinyl alcohol) (PVA) were successfully prepared and applied as drug carriers for transdermal drug delivery system. Sodium Salicylate (SS) was the model drug and it was incorporated in the PVA fibers by adding 20 % of SS in a PVA solution prior to electrospinning. Electrospinning of SS-containing PVA solution resulted in the formation of beaded fibers. In order to control the rate of SS release and decrease water solubility of PVA, the SS-loaded electrospun PVA mat was cross-linked by either glutaraldehyde or glyoxal vapor. The morphology, thermal behavior, swelling behavior, release characteristic, kinetics of drug release and also toxicity of the cross-linked sample were investigated.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.15 no.2
• /
• pp.171-174
• /
• 2007

Sericin beads were prepared from ethanol-precipitated sericin. The addition of ethanol into hot-water extracted sericin solution induced precipitation of sericin and thereby some sericin could be fractionated. The ethanol-precipitated sericin (EpSS) had narrower molecular weight distribution than original sericin. The EpSS had mainly random coil structure with small portion of ${\beta}-sheet$ structure. With the EpSS, spherical beads could be prepared at lower concentration than with original sericin due to higher viscosity. The EpSS beads had better compressive strength than the original sericin beads and had rubber-like property. Our results suggest that EpSS is more compatible in the polymeric field, since it has better mechanical strength than original sericin.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.11
• /
• pp.855-865
• /
• 1991

A simple method for analysis of serial search burst-format direct-sequence spread-spectrum (DS-SS) code acquisition system had been recently proposed, and therein, the effect of the code autocorrelation sidelobes on the performance of DS-SS code acquisition system has been assessed [4],[5]. In this paper, a new hybrid scheme which combines the serial search with maximum likelihood search is proposed to eliminate the deleterious effect of code autocorrelation sidelobes, and the performance is analyzed for the additive withe Gaussian noise (AWGN) channels. To analyze the performance of this system, we have generalized the method used in [4],[5] to arbitrary burst-format DS-SS acquisition schemes. The results show that a new hybrid scheme has good immunity against the effect of code autocorrelation sidelobes. Thevalidity of the presented approach has been confirmed form the results of simulation.

• Journal of Oral Medicine and Pain
• /
• v.40 no.3
• /
• pp.130-134
• /
• 2015

$Sj{\ddot{o}}gren's$ syndrome (SS) is an autoimmune disease characterized by an autoimmune exocrinopathy involving mainly salivary and lacrimal glands. Apart from manifestations due to involvement of exocrine glands, patients with SS can present with muscular and neurological manifestations. Here, we report a rare case of a 59-year-old woman with primary SS, who presented with severe general toothache and masticatory muscle myalgia successfully treated with clonazepam. Although it was not certain that these symptoms could be originated from focal muscle dystonia or neurological changes that are associated with primary SS, our case suggested that comprehensive evaluation including neuromuscular examinations in the oral and maxillofacial area is needed in patients with SS.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.34S no.1
• /
• pp.9-15
• /
• 1997

In this paper, the performance of a hybrid direct-sequence/slow-frequency-hoped (DS/SFH) spread-spectrum (SS) system with noncoherent DPSK modulation is considered. Th ebit error probability is derived ovef a rayleigh fading channel in the presence of multiple tone jamming. Numerical evaluations are presented for some combinations of system parameters. The performance of a hybrid DS/SFH SS system is shown to be inferior to that of a pure DS SS system at low jamming-to-signal power ratio (JSR). At high JSR, the performance of a pure DS SS system is shown to be the same as the worst case peformance of a hybrid DS/SFH SS system.

• Journal of Agricultural Extension & Community Development
• /
• v.11 no.1
• /
• pp.161-174
• /
• 2004

This paper discussed community ecological approach for Environmentally Sound and Sustainable Development(ESSD) and Sustainable Society(SS). Community ecology is composed of nature, environment and diverse species and is dynamic and sustainable system by interaction among those components. It is required long-term, integrating and eco-centric stances to achieve ESSD and SS such as eco-city and eco-village movements. This is integrated and complicated perspective beyond traditional dichotomy between human and environment. Community ecological perspective directs people toward ecological society system which creates and maintains adaptable life style under ecological situation in community. Building up eco-parts, eco-cites, eco-villages are crucial movements for promoting human's environmental living standards. These sustainable community movements require people to change their values and life styles suitable for their SS. It is required integrated and balanced perspective and participating endeavor of residents to maintain SS.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.1
• /
• pp.67-73
• /
• 2005

In order to compensate for the degradation caused by the frequency shift under the Rayleigh fading with the balanced QPSK DS-SS communication, it is necessary to devise an efficient phase estimation method. In this paper, using the pilot signal, three conventional methods and a complex number method are presented and compared. The performance comparison results show that the combination complex number method is better than the other conventional methods, which have some limiting conditions.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.1316-1319
• /
• 2002

In this paper, an online SNR estimator is derived for turbo coded multicode DS/SS systems in Nakagami fading channels. The multicode DS/SS approach is one of promising solutions to obtain higher-rate data transmission in DS/SS technologies. Turbo coding has paid much attention because of the significant improvements on error rate performances in various communication systems including multicode DS/SS systems. However, in the turbo decoding, channel state information, especially signal-to-noise ratio (SNR) at the correlator outputs, is desired in order to obtain such improvements. We evaluate the accuracy of the derived SNR estimation. It is shown that the bit error rate performance using our SNR estimation is close to the performance with perfect knowledge of channel state information.

• Korean journal of applied entomology
• /
• v.29 no.3
• /
• pp.190-193
• /
• 1990

To establish the successive rearing method of the perilla leaf pyralid, Prausta panopealis Walker, experiments were carried out wiht three diets based on a JAMSI-type artificial die for silkworm. On the SS4 diet containing 40% of perilla leaf powder the pupal and adult yields were higher than those on th fresh green perilla leaves.