• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.97-103
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• 2001

The effects of the electrohydrodynamic (EHD) flow and turbulent diffusion on the collection efficiency of a model ESP composed of the plates with a cavity were studied through numerical computation. The electric field and ion space charge density were calculated by the Poisson equation of the electrical potential and the current continuity equation. The EHD flow field was solved by the continuity and momentum equations of the gas phase including the electrical body force induced by the movement of ions under the electric field. The RNG $k-{\varepsilon}$ model was used to analyze the turbulent flow. The particle concentration distribution was calculated from the convective diffusion equation of the particle phase. As the ion space charge increased, the particulate collection efficiency increased because the electrical potential increased over the entire domain in the ESP. The collection efficiency decreased and then increased, i.e. had a minimum value, as the EHD circulating flow became stronger when the electrical migration velocity of the charged particle was low. However, the collection efficiency decreased with the stronger EHD flow when the electrical migration of the particle was higher relatively. The collection efficiency of the model ESP increased as the turbulent diffusivity of the particle increased when the electrical migration velocity of the particle was low. However, the collection efficiency decreased for increasing the turbulent diffusivity when the electrical migration of the particle was higher relatively.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2012년도 제46차 하계학술발표논문집 20권2호
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• pp.87-88
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• 2012

Because intra prediction modes in H.264 are determined by the brightness continuity between neighboring blocks, they can be used as a method for extracting edge information in the compression domain. However, if we just consider 9 intra prediction modes in H.264 as 9 different edge directions, we have the following two problems. First, intra prediction modes tend to yield too many edge blocks, generating unnecessary edge information. Second, we may not need all 9 directional edges (including the DC type) in H.264 intra prediction modes. For example, the EHD (edge histogram descriptor) in MPEG-7 defines only 4 directional edge types, namely horizontal, vertical, diagonal (HVD) edges with $0^{\circ}$, $90^{\circ}$, $45^{\circ}$, and $135^{\circ}$. Here, semi-diagonal (SD) edge types with $112.5^{\circ}$, $157.5^{\circ}$, $22.5^{\circ}$, and $67.5^{\circ}$ in the intra prediction modes in H.264 are not used. In this paper. we prepose a method that removes unnecessary edges from the intra prediction modes by utilizing the total average coefficient of 4x4 blocks in each slice and assign SD edges to HVD (horizontal, vertical, diagonal, $0^{\circ}$, $90^{\circ}$, $45^{\circ}$, $135^{\circ}$) edges by the contextual information of the neighboring blocks. Experimental results show that the edges determined by the proposed method in the compression domain are comparable to those of the previous edge detection methods in the spatial domain.

• Korean Journal of Radiology
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• 제22권1호
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• pp.41-62
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• 2021

Radiologic imaging is important for evaluating extrahepatic bile duct (EHD) cancers; it is used for staging tumors and evaluating the suitability of surgical resection, as surgery may be contraindicated in some cases regardless of tumor stage. However, the published general recommendations for EHD cancer and recommendations guided by the perspectives of radiologists are limited. The Korean Society of Abdominal Radiology (KSAR) study group for EHD cancer developed key questions and corresponding recommendations for the radiologic evaluation of EHD cancer and organized them into 4 sections: nomenclature and definition, imaging technique, cancer evaluation, and tumor response. A structured reporting form was also developed to allow the progressive accumulation of standardized data, which will facilitate multicenter studies and contribute more evidence for the development of recommendations.

• 동의생리병리학회지
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• 제23권2호
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• pp.337-342
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• 2009

Acquired pigmentary skin diseases such as abnormal melanogenesis, vitiligo, chloasma and inflammatory pigmentation are related to regulate the melanin production, In this study, an ethanol extract of Hovenia dulcis Thunb.(EHD) makedly inhibited melanin biosynthesis and suppressed, the protein expression of tyrosinase, tyrosinase-related protein 1(TRP-1), and tyrosinase-related protein 2(TRP-2) in B16F10 cells. On the other hand, EHD did not inhibit mushroom tyrosinase activity. These results indicate that EHD may contribute to the inhibition of melanin biosynthesis through regulating tyrosinase activity and expression, and serve as a new candidate in the design of new skin-whitening or therapeutic agents.

• Molecules and Cells
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• 제41권7호
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• pp.665-675
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• 2018

Rice is a facultative short-day (SD) plant in which flowering is induced under SD conditions or by other environmental factors and internal genetic programs. Overexpression of Histone Deacetylase 701 (HDT701) accelerates flowering in hybrid rice. In this study, mutants defective in HDT701 flowered late under both SD and long-day conditions. Expression levels of florigens Heading date 3a (Hd3a) and Rice Flowering Locus T1 (RFT1), and their immediate upstream floral activator Early heading date 1 (Ehd1), were significantly decreased in the hdt701 mutants, indicating that HDT701 functions upstream of Ehd1 in controlling flowering time. Transcript levels of OsINDETERMINATE SPIKELET 1 (OsIDS1), an upstream repressor of Ehd1, were significantly increased in the mutants while those of OsGI and Hd1 were reduced. Chromatin-immunoprecipitation assays revealed that HDT701 directly binds to the promoter region of OsIDS1. These results suggest that HDT701 induces flowering by suppressing OsIDS1.

• 한국응용과학기술학회지
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• 제30권3호
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• pp.400-410
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• 2013

This study was carried out to investigate the effects of feeding the broilers that are exposed to extreme heat stress by control of inverse lighting times with night restricted feeding of extreme heat diet(EHD1, 2: extreme heat diet) containing different amount of soy oil, molasses, amino acids and vitamin C on short chain fatty acid and blood lipid profile. 300 broiler chickens(Abaica strain) were randomized into four dietary treatment groups according to a randomized block design on the day they were hatched. The four dietary treatment groups were: T1(EHD 1, 10:00~19:00 Dark, 19:00~10:00 Light), T2(EHD 2, 10:00~19:00 Dark, 19:00~10:00 Light), T3(EHD 1, 09:00~18:00 Dark, 18:00~09:00 Light), T4(EHD 2, 09:00~18:00 Dark, 18:00~09:00 Light). The body weight gain of the broilers was highest in T2, and high in order T1, T4, T3(p<0.05). Weights of the lymphoid organ, thymus and bursa of Fabricius were high in T1, T2 as compared to T3, T4 but spleen was lower in T4 than T1, T2, T3(p<0.05). Blood triglyceride, total cholesterol and glucose were higher in T1, T2 than T3, T4(p<0.05). LDL-C was high in orderT4, T3, T2, T1 but HDL-C showed the opposite trend(p<0.05). Blood concentrations of IgG, IgG and IgM were higher in T1, T2 than inT3, T4, but the corticosterone concentration decreased significantly in them. In T1 and T2, Lactobacillus in the feces increased, but total aerobic bacteria, E.coli, coliform bacteria was decreased rather significantly, compared with those in T3 and T4(p<0.05). Concentrations of acetic acid, propionic acid and total SCFA in cecum were high in order T2, T1, T3, T4, but butyric acid, isobutyric acid, valeric acid, isovaleric acid were lower in T1, T2 than in T3, T4 (p<0.05).

• 기계와재료
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• 제4권4호통권14호
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• pp.50-58
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• 1992

• 한국전산유체공학회지
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• 제13권4호
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• pp.58-65
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• 2008

In the present study, a numerical analysis on electrohydrodynamics (EHD) of the flow and the collection mechanisms inside a electrostatic precipitator with a spiral spike electrode were investigated. The phenomena of the electrostatic precipitator include complex interactions between the electric field, the fluid flow and the particle motion. To validate the numerical method, the numerical computation for the electric field of a simple wire-pipe type electrostatic system having an analytic solution were performed. Using this numerical method, the electric field of the spiked electrostatic precipitator was simulated. And the fluid flow and the particle motion inside the spiked electrostatic precipitator were numerically analyzed.

• Tribology and Lubricants
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• 제14권2호
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• pp.26-34
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• 1998

This paper presents a high-speed performance analysis of ball bearings with ceramic balls under thrust loads. The sliding velocity profiles between a ball and raceways were obtained by the 3-D quasi-dynamic equations of motion including both centrifugal force and gyroscopic moment derived by vector matrix algebra. The friction at the contact areas was obtained by the Bair-Winer's non-Newtonian rheological model and the Hamrock-Dowson's central film thickness in EHL analysis. The nonlinear equations were solved by the Newton-Raphson method and the underrelaxation iterative method. The friction torques and ball behaviors with various loads, ball materials, and contact angles were predicted by this model. It was shown that the friction torque was sensitive to thrust load and contact angle, and that the friction torque and the pitch angle of the bearing with ceramic balls are smaller than those of the bearing with steel balls.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.79-80
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• 2002

This paper presents an experimental study of the effect of rolling speed and surface roughness on the mixed elastohydrodynamic (EHD) lubrication characteristics for point contact formed between a real, random, rough surface, steel ball and smooth glass disc. The Thin Film Colorimetic Interferometry measurement technique has been extended to give detailed information about in-contact deformation of the microgeometry. It has enabled to derive the amplitude reduction curve that shows progressive recovering of ball roughness features with increasing speed.