• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.93-99
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• 2019

The purpose of this study was to investigate the bond strength between PEKK(Polyetherketoneketone) and Sinfony(3M ESPE, Seefeld, Germany) the dental composite resin by proposing the three representative surface treatment methods and evaluate to see if they affect the bond strength between two materials. A total of 30 PEKK($Pekkton^{(R)}$ Ivory, $Cendres+M{\acute{e}}taux$, Bienne, Switzerland) specimens were prepared, embedded in acrylic resin, polished(P 1200 grid) to surface, and each group was divided into 10 specimens. After then, by the surface treatment method, it classified into three groups(n=10) such as Air abrasion group(PN), applying Single Bond Universal(3M ESPE) after Air abrasion(PB), applying OPAQUE(3M ESPE) after Air abrasion(PO). Then, veneering was performed by using Sinfony(3M ESPE, Seefeld, Germany). All completed specimens were allowed to rest in a $37^{\circ}C$ water bath for 24 hours. Shear bond strength of each group was measured and fracture patterns were classified. Statistic analysis was performed with One-way ANOVA followed by post hoc Scheffe tast (p<.05). Statistical analysis was performed using the SPSSWIN 21.0 program. As a result of one-way ANOVA, the average value of PB group was $27.67{\pm}4,18MPa$ and it was shown as the highest bond strength, PN and PO were $20.43{\pm}1.70$ and $19.8{\pm}4.77MPa$ each, and these were relatively low(F=18.4, P<.001), and as the post-test the Scheffe test was conducted and verified (p<.05). After examining the scheffe test, it was showed significant differences as PB>PO, PB>PN(p<.001). Through this study, in order to enhance the bonding force between PEKK and the composite resin, perform the Air abrasion and surface treatment by using Single Bond Universal(3M ESPE) is recommended, and as coMPared with other studies. And it is assumed that the increase of the application time of the Air abrasion affects the increase of the shear bond strength. Thus, further research is required.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.5
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• pp.57-61
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• 2001

This study introduces an algorithm for determination of hypocentral parameters using phase analysis and two-point ray tracing to enhance accuracy and stability of computations. When the magnitude of earthquake is relatively small(usually $m_{b}$<3.2), the PmP phase which looks like the first arrival phase may be observed without observing the Pn phase. In this case, the hypocentral parameters calculated by the existing method using the first arrival of P and S phases and by the method developed in this study using PmP and SmS phases show large differences. The computational results of determination of hypocentral parameters for actual earthquake events show that this method gives much smaller rms errors than the existing methods do.o.

• ALGAE
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• v.19 no.3
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• pp.207-216
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• 2004

Characteristics of photosynthesis-light and photosynthesis-temperature relationships were seasonally compared among 4 species, two temperate Sargassurn (S. ringgoldianum and S. spathulophyllum) and two temperate kelp (Ecklonia cava and Eisenia bicyclis), growing in the same habitat in Oura Bay, Shimoda, central Japan. The photosynthesis-irradiance (P-I) curve of each species at the in situ temperature and the photosynthesis-temperature (P-T) curve at near saturation irradiance (400μmol·m^(-2)·s^(-1)) were determined by using differential gas-volumeters. Maximum photosynthetic rates (Prnax) for P-I curves of the two Sargassurn species were higher from summer to autumn than from winter to spring, while those of the two kelp species showed little difference among seasons. Net photosynthetic rates (Pn) at 100-400μmol·m^(-2)·s^(-1) of the Sargassurn species were higher than those of the kelp species in autumn, spring and summer, while in winter the rates were about the same between the Sargassurn and kelp species. Among seasons, the light saturation index (1k) values, dark respiration rates and light compensation points of Sargassurn species differed more than those of kelp species. Optimum temperature for P-T curves of Sargassurn species was 29℃ and that of kelp species was 27℃ in summer, while in winter the former was 27℃ and the latter was 25℃. Pn at 400 μmol·m^(-2)·s^(-1) at 10-33℃ of Sargassurn species were considerably higher than those of kelp species from spring to summer, while from autumn to winter the rates at 5-27℃ were about the same between the two. At supra-optimum temperatures, Pn of kelp species decreased more sharply than those of Sargassurn species in each season. These facts indicate that the two temperate Sargassurn species have a higher potential photosynthetic performance under warmer conditions than the two temperate kelp species even though they grow in the same habitat.

• Journal of Ginseng Research
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• v.36 no.1
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• pp.93-101
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• 2012

This study evaluated the anti-cholinesterases (ChEs) and antioxidant activities of white ginseng (WG) and black ginseng (BG) roots of Panax ginseng (PG), P. quinquefolium (PQ), and P. notoginseng (PN). Ginsenosides $Rg_1$, Re, Rf, $Rb_1$, Rc, $Rb_2$, and Rd were found in white PG, whereas Rf was not found in white PQ and Rf, Rc, and $Rb_2$ were not detected in white PN. The major ginsenoside content in steamed BG including $RK_3$, $Rh_4$, and 20(S)/(R)-$Rg_3$ was equivalent to approximately 70% of the total ginsenoside content. The WG and BG inhibited acetylcholinesteras (AChE) and butyrylcholinesterase (BChE) in a dose dependent manner. The efficacy of BG roots of PG, PQ, and PN on AChE and BChE inhibition was greater than that of the respective WG roots. The total phenolic contents and 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) scavenging activity were increased by heat treatment. Among the three WG and BG, white PG and steamed black PQ have significantly higher contents of phenolic compounds. The best results for the DPPH scavenging activity were obtained with the WG and BG from PG. These results demonstrate that the steamed BG roots of the three studied ginseng species have both high ChEs inhibition capacity and antioxidant activity.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.75-76
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• 2006

New PM route via bulk mechanical alloying is developed to fabricate the solid solution semi-conductive materials with $Mg_2Si_{1-x}Ge_x$ and $Mg_2Si_{1-y}Sn_y$ for 0 < x, y < 1 and to investigate their thermoelectric materials. Since $Mg_2Si$ is n-type and both $Mg_2Ge$ and $Mg_2Sn$ are p-type, pn-transition takes place at the specified range of germanium content, x, and tin content, y. Through optimization of chemical composition, solid-solution type thermoelectric semi-conductive materials are designed both for n-and p-type materials.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.65-66
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• 2012

부하 시스템의 용량 증대와 중요도에 따른 신뢰성 향상을 위해 Uninterruptible Power Supply(UPS)의 병렬운전 연구가 활발히 진행되고 있다. 본 논문은 droop특성을 적용한 3상 UPS의 병렬운전 제어 알고리즘을 제안한다. 또, 기존의 droop 제어기를 적용한 UPS의 plug-and-play(PnP) 운전시 순환 전류의 원인을 분석하고 PnP 운전이 가능한 droop 제어기를 제안한다. 그리고 제안된 알고리즘의 타당성을 검증하기 위해 PSIM을 통해 시뮬레이션을 수행하였다.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.295-301
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• 2021

Digital media technology is gradually developing with the development of convergence quaternary industrial technology and mobile devices. The combination of deep learning and augmented reality can provide more convenient and lively services through the interaction of 3D virtual images with the real world. We combine deep learning-based pose prediction with augmented reality technology. We predict the eight vertices of the bounding box of the object in the image. Using the predicted eight vertices(x,y), eight vertices(x,y,z) of 3D mesh, and the intrinsic parameter of the smartphone camera, we compute the external parameters of the camera through the PnP algorithm. We calculate the distance to the object and the degree of rotation of the object using the external parameter and apply to AR content. Our method provides services in a web environment, making it highly accessible to users and easy to maintain the system. As we provide augmented reality services using consumers' smartphone cameras, we can apply them to various business fields.

• Korean journal of food and cookery science
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• v.21 no.5
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• pp.685-692
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• 2005

This study summarizes our findings on the effect of pine needle powder and water extract on the quality characteristics of wet noodle and the changes of microbial count during storage. The lightness of wet noodles was significantly decreased with increasing amounts of PN powder and water extract added in the noodles(p<.001), whereas the redness and yellowness of the noodles were significantly increased(p<.001). Texture evaluation showed that springiness was the highest in the noodle prepared with 5% PN extract, whereas brittleness was the lowest in 1% PN extract. At the beginning period of storage, there were significant differences of microbial cell count in PCA and PDA among the samples, but a significant decreasing was observed after 6 days. In the relationship between sensory and mechanical properties, a negative correlation was observed between color and sleekness, while there was a positive correlation with redness and yellowness. Sensory evaluation showed that odor, taste, texture and overall acceptability were the best in noodles processed with 3% PN extract.

• Journal of Cardiovascular Imaging
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• v.26 no.4
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• pp.217-225
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• 2018

BACKGROUND: In patients with acute heart failure (AHF), diastolic dysfunction, especially pseudonormal (PN) or restrictive filling pattern (RFP) of left ventricle (LV), is considered to be implicated in a poor prognosis. However, prognostic significance of diastolic dysfunction in patients with ischemic heart disease (IHD) has been rarely investigated in Korea. METHODS: We enrolled 138 patients with IHD presenting as AHF and sinus rhythm during echocardiographic study. Diastolic dysfunction of LV was graded as ${\geq}2$ (group 1) or 1 (group 2) according to usual algorithm using E/A ratio and deceleration time of mitral inflow, E'/A' ratio of tissue Doppler echocardiography and left atrial size. RESULTS: Patients in group 1 showed higher 2-year mortality rate ($36.2%{\pm}6.7%$) than those in group 2 ($13.6%{\pm}4.5%$; p = 0.008). Two-year mortality rate of patient with LV ejection fraction (LVEF) < 40% ($26.8%{\pm}6.0%$) was not different from those with LVEF 40%-49% ($28.0%{\pm}8.0%$) or ${\geq}50%$ ($13.7%{\pm}7.4%$; p = 0.442). On univariate analysis, PN or RFP of LV, higher stage of chronic kidney disease (CKD) and higher New York Heart Association (NYHA) functional class were poor prognostic factors, but LVEF or older age ${\geq}75$ years did not predict 2-year mortality. On multivariate analysis, PN or RFP of LV (hazard ratio [HR], 2.52; 95% confidence interval [CI], 1.09-5.84; p = 0.031), higher stage of CKD (HR, 1.57; 95% CI, 1.14-2.17; p = 0.006) and higher NYHA functional class (HR, 1.81; 95% CI, 1.11-2.94; p = 0.017) were still significant prognostic factors for 2-year mortality. CONCLUSIONS: PN or RFP of LV was a more useful prognostic factor for long-term mortality than LVEF in patients with IHD presenting as AHF.

• Journal of Embryo Transfer
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• v.16 no.2
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• pp.107-115
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• 2001

Development of effective activation protocols is of great importance for improving the success of cloning and subsequent transgenic. Three methods for oocyte activation, including 5$\mu$M ionomycin (5 min) alone, ionomycin + 1.9 mM 6-dimetylaminopurine (DMAP, 3 hrs) and ionomycin + 10 $\mu\textrm{g}$/ml cycloheximide (CHX, 3 hrs) were compared for their effects of pronuclei (PN) formation, development, developmental velocity and ploidy of parthenotes to IVF control in bovine. In group of ionomycin + DMAP, the oocytes having more 3PN were significantly (P<0.05) higher than in groups of ionomycin alone and of ionomycin + CHX (45.5% vs. 0 and 0%, respectively). Activation with the ionomycin alone, ionomycin + DMAP and ionomycin + CHX resulted in cleavage rates of 30, 85.5 and 57.9%, respectively. The blastocysts rate of parthenotes activated by ionomycin + DMAP treatment was significantly higher (12.3%. p<0.05) than those of other treated groups. Chromosome analysis shows that ionomycin + DMAP treatment greatly enhances the incidence of chromosomal abnormality of the parthenotes. From the results, we may conclude that DMAP treatment to the oocytes accelerates developmental velocity resulting in both the higher incidence of chromosome abnormality and of PN formation, and strongly suggest that CHX combined with ionomycin is better than DMAP for the purpose of successful nuclear transplantation. Developmental velocity of parthenotes activated by ionomycin + DMAP treatment was significantly (P<0.05) faster than others.