• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.11a
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• pp.407-411
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• 2002

Ternary sequences are digital codes consisting of discrete values -1, 0, and 1 only. They are advantageous in that the correlation can be carried out using additions only. Also, they feature an ideal circular autocorrelation function, but in channel characterization tasks, the usual requirement is that the linear autocorrelation function be ideal, i.e., a Kronecker delta function. In this article, we consider two approaches to improving their linear autocorrelation or crosscorrelation properties: one is an inverse filtering method with thresholding, and the other is a singular value decomposition (SVD) method. Both methods are simulated under noisy circumstances. The inverse filtering method resulted in an improvement in peak sidelobe level of about 11 dB at an SNR of 30 dB, and the SVD method showed similar performances, albeit more sensitive to noise depending on the singular value selection strategy.

• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.635-641
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• 2006

In an attempt to find ways of improving the quality and sanitary state of dried squid, this study compared artificial drying methods i.e. hot air drying and cold air drying with natural drying method. The drying rates of squid were in the order of hot air, cold air and natural drying. However, cold-air drying was slower than natural drying at $7^{\circ}C$. The drying rates increased with increasing drying temperature. When drying temperature was close to the dew point on a dehumidifier surface, which was the case with cold air drying at $7^{\circ}C$, the driving force for dehumidification was lower than under other drying conditions, which resulted in a lower drying rate. There were little color differences between the drying methods and temperature. Squid dried by cold air-drying had better mechanical texture and sensory qualities than with other drying methods. In addition, the cold air drying method maintained superior quality in terms of the contents of amino acids, taurine, EPA, DHA, other fatty acids and a low TBA value than the other drying methods.

• Journal of Welding and Joining
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• v.32 no.3
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• pp.95-101
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• 2014

Joining of grey cast iron by fusion welding has much difficulties for its extremely low ductility and low toughness because of the flake form of the graphite. And the brittle microstructure, i.e. ledeburite may be formed during fusion welding by its rapid cooling rates. By these kinds of welding problem, preheat and post heat treatment temperature must be increased to avoid weld crack or welding problems. In order to avoid these fusion welding problem, friction welding of cast iron was carried out for improving joint soundness, establishing friction welding variables. There is no factor for evaluating friction weldability in continuous drive type friction welding. In this point of view, this study proposed the parameters for calculating friction weld heat input. The results obtained are as follows ; 1. There was a close relationship between tensile strength and flash appearance of friction welded joint. 2. Tensile strength was decreased and flash was severely oxidized as increasing frictional heating time. 3. As increased forging pressure $P_2$, flash had a large crack and tensile strength was decreased. 4. As powdered graphite by rotational frictional force induced flat surface and hindered plastic flow of metal, tensile strength of welded joint was decreased. 5. Heat input for continuous drive type friction welding could be calculated by the factors of $P_1$, $P_2$ and upset distance(${\delta}$).

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.201-206
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• 2000

Effects of the post-annealing temperature of CeO$_2$ buffer layers on the properties of YBCO films on CeO$_2$-buffered sapphire were investigated. 45 nm-thick CeO$_2$ buffer layer was prepared in-situ on r-cut sapphire using an on-axis rf magnetron sputtering method, which was later post-annealed at temperatures between 950$^{\circ}$C and 1100$^{\circ}$C in an oxygen-flowing environment. YBCO films were prepared on CeO$_2$-buffered sapphire (CbS), for which the surface morphology, crystal structures and electrical properties of the YBCO films were studied. YBCO films on post-annealed CbS appeared to have better properties than those on as-grown CbS with regard to the morphological, structural and electrical properties when the YBCO films were prepared on CeO$_2$ buffer layer post-annealed at temperatures of 1000 - 1050$^{\circ}$C. A TE$_{011}$ mode rutileloaded cylindrical cavity resonators was fabricated with the YBCO films placed as the endplates, for which the unloaded Q of the resonator was measured. It turned out that the resonator with the endplates prepared from the YBCO films on postannealed CbS at 1000 $^{\circ}$C showed the highest unloaded Q with the value more than 8 ${\times}$ 10$^5$ at 30 K and 8.6 CHz, revealing that the YBCO films on post-annealed CbS at 1000$^{\circ}$C the temperature could be the lowest among the YBCO films on post-annealed CbS.

• Progress in Superconductivity
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• v.11 no.2
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• pp.106-111
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• 2010

Sapphire resonators with $YBa_2Cu_3O_{7-\delta}$ (YBCO) endplates have provided a way to realize extremely high quality factor due to the extremely low dielectric loss of sapphire and conductive loss of YBCO films, which enables to measure the low surface resistance of superconductor films at microwave frequencies. We present microwave properties of HTS sapphire resonators designed for measuring the surface resistance of HTS films at millimeter-wave frequencies by using the two-resonance mode dielectric resonator method. Despite enhanced surface resistance ($R_S$) of YBCO films due to the quadratic frequency dependence of the $R_S$, the unloaded quality factor ($Q_0$) of the $TE_{021}$ mode sapphire resonator still appears to be well above $1\;{\times}\;10^6$ at a mm-wave frequency of 38 GHz at 10 K. However, it appears that the $TE_{012}$ mode $Q_0$ is unexpectedly low despite that the corresponding resonance peak looks uncoupled with parasitic modes. We discuss possible reasons for the unexpected results using the surface resistance at the $TE_{021}$, $TE_{012}$, and $TE_{011}$ mode frequencies.

• Progress in Superconductivity and Cryogenics
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• v.15 no.4
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• pp.15-20
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• 2013

We investigated the flux pinning properties of both 10 mol% Zr-and Sn-doped $YBa_2Cu_3O_{7-{\delta}}$ (YBCO) films with the same thickness of ~350 nm for a comparative purpose. The films were prepared on the $SrTiO_3$ (STO) single crystal substrate by the metal-organic deposition (MOD) process. Compared with Sn-doped YBCO film, Zr-doped one exhibited a significant enhancement in the critical current density ($J_c$) and pinning force density ($F_p$). The anisotropic $J_{c,min}/J_{c,max}$ ratio in the field-angle dependence of $J_c$ at 77 K for 1 T was also improved from 0.23 for Sn-doped YBCO to 0.39 for Zr-doped YBCO. Thus, the highest magnetic $J_c$ values of 9.0 and $2.9MA/cm^2$ with the maximum $F_p$ ($F_{p,max}$) values of 19 and $5GN/m^3$ at 65 and 77 K for H // c, respectively, could be achieved from Zr-doped YBCO film. The stronger pinning effect in Zr-doped YBCO film is attributable to smaller $BaZrO_3$ (BZO) nanoparticles (the average size ${\approx}28.4$ nm) than $YBa_2SnO_{5.5}$ (YBSO) nanoparticles (the average size ${\approx}45.0$ nm) incorporated in Sn-doped YBCO film since smaller nanoparticles can generate more defects acting as effective flux pinning sites due to larger incoherent interfacial area for the same doping concentration.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1244-1245
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• 2008

Recently, piezoelectric transformer is applied to wide fields. Multi layer piezoelectric transformer has the advantage of high step up ratio, electromechanical coupling coefficient(Kp) and mechanical quality factor(Qm), but is indicated of peeling-phenomenon of electrode, rising sintering temperature made price of costly electrode. So in this study, it discuss on method for fabrication of rosen type piezoelectric transformers. For the fabrication as rosen type piezoelectric transformers, synthesized the powder using 0.01Pb$(ni_{1/3}Nb_{2/3})O_3$ - 0.08Pb$(Mn_{1/3}Nb_{2/3})O_3$ - 0.91Pb$(Zr_{0506}Ti_{0496})O_3$ (abbreviated as PNN-PMN-PZT) ceramics. The density, microstructure, dielectric and piezoelectric properties as a function of sintering temperature were investigated. The results indicated that the optimized properties of ceramics were obtained at sintering temperature of 1200$^{\circ}C$, showed the value of $d_{33}$=273pC/N, $K_p$=0.60 $Q_m$=1585, ${\varepsilon}_r$=1454, density=7.917$g/cm^3$ and $tan{\delta}$=0.0064.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.3
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• pp.281-288
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• 2004

The hybrid composite material (Al/GFRP laminates) are applied to the fuselage and wing in a aircraft. Therefore, Al/GFRP laminates suffer from the cyclic bending moments. This study was to evaluate the effect of fiber stacking angle on the fatigue crack propagation and delamination behavior using the relationship between crack growth rate (da/dN) and stress intensity factor range (ΔK) in Al/GFRP laminates under cyclic bending moment. The variable delamination growth behavior in case of three different type of fiber orientations, i.e., [Al/O$_2$/Al], [Al/+45$_2$/Al] and [Al/90$_2$/Al] at the interface of Al layer and glass fiber layer was measured by ultrasonic C-scan images. As results of this study, It represent that the delamination shape should turns out to have more effective characteristics on the fiber stacking angle. The extension of the delamination zone in case of [Al/+45$_2$/Al] and [Al/90$_2$/Al] were not formed along the fatigue crack profile. The shape of delamination zone depend on fiber stacking angle and the variable type with the delamination contour decreased non-linearly toward the crack tip at the Al layer.

• Korean Journal of Oriental Medicine
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• v.2 no.1
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• pp.514-550
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• 1996

There are many theory in acupuncture mechanism, so we must know the detail contents. and then we can use the acupuncture as we know. the follow article will be helpful in this part. 1. Spinal cord are role in intermediate part in somatosensorypathway also in acupuncture stumulating tract 2. Acute pain pathway started in laminae I, V of gray colmn, next are the spinothalamic tract(trigeminal spinothalamic tract in above neck part) and then go to the specific thalamic nucleus. but chronic pain in laminae II, III, VI, VII, next are spinoreticular tract(trigeminal spinoreticular tract in the neck part) and finally to the nonspecific thalamic nucleus. 3. Thalamus is very important area in somatosensory stimuation including acupuncture stumulating sensory also as a pain control center. but except this, there are Hypothalamus, Limbic system Cerebral cortex and Cerebellum as intermediator. as we Know hypothalamus is related to the emotional analgesic system with a limbic system. 4. A ${\delta$ fiber has relationship in Acute, sharp and initial pain, contrary this C fiber is related with Chronic, dull and last pain. 5. In Acupuncture mechanism of pain analgesia, there are two theory, one is gate control theory as large fiber another is stimuation produced analgesia as small diameter fier. 6. In DNIC, the stimulation sources are mechanical, thermal, heating, pain and acupuncture stimulation etc. we call these as a Heterotopic Noxious Stimulation. 7. In DNIC, SRD(Subnucleus reticularis dorsalis)is core nucleus in pain imtermediated analgesic mechanism. 8. Takeshige insisted nonacupuncture point dependent analgesic mechanism and acupuncture point dependent analgesic mechanism. and protested that Stimulation acupuncture piing evoke blocking nomacupuncture point analgesic pathway.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.3
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• pp.92-105
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• 2010

Objectives: The purpose of this study is to investigate the effects of Daecheongryong-tang (DCRT) on the adipogenesis in 3T3-L1 preadipocytes. Methods: 3T3-L1 preadipocytes were differentiated with adipogenic reagents by incubating for 2 days in the absence or presence of DCRT ranging 0.25 and 2%. The effect of DCRT on adipogenesis was examined by Oil red O staining, and the protein, RNA, and RT-PCR were measured. Results: Our results showed that DCRT decreased the TG content by ORO staining. To elucidate the mechanism of the effects of DCRT on lowering TG content in 3T3-L1 adipocytes, we examined the DCRT modulate expressions of transcription factors to induce adipogenesis and adipogenic genes which is related to the regulation of accumulation of lipids. As a result, the expression of SREBP1, C/$EBP{\beta}$, C/$EBP{\delta}$, C/$EBP{\alpha}$, and $PPAR{\gamma}$ genes, which induce the adipose differentiation and adipose-specific aP2, adipsin, LPL, CD36, TGF-${\beta}$ and adiponectin genes which regulates fat formations, were decreased. In addition, DCRT reduced the expression of iNOS and IL-6 in 3T3-L1 adipocytes, resulting in inflammation. Conclusions: DCRT could regulate transcript factor related to induction of adipose differentiation, inhibit the accumulation of lipids and expression of the adipogenic genes.