• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.6
• /
• pp.2160-2170
• /
• 1991

Three-dimensional turbulent structures in the near field of elliptic jet were experimentally investigated by using a three-color, three-component Laser Doppler Velocimeter. The Reynolds number based on the nozzle exit velocity and nozzle equivalent diameter(De) was about 4*10$^{4}$. The turbulent characteristics of a sharp-edged elliptic nozzle with aspect ratio of 2 were analyzed along major and minor axis at X/De=2,3,5,7 and along the centerline up to X/De=14. Quantities measured at each point with the 3-D LDV system were three orthogonal velocity components, turbulent intensity, skewness, flatness, and Reynolds shear stress. The nondimensional mean velocities coincided well with the Schlichting's empirical curve with going downstream. Elliptic jet of AR=2 had two switching points at about X/De=2 and 16. The turbulent intensity along the minor axis was distributed widely than that along the major axis. In the near field, X/De<5, the Reynolds shear stresses of the inner part of the elliptic jet had negative value, which indicated the enhancement of entrainment toward the inner part.

• Applied Biological Chemistry
• /
• v.36 no.3
• /
• pp.197-202
• /
• 1993

In order to explore the brassinosteroid-active component in Perilla frutescense, methanol extract of immature seeds was purified by sequences of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography, charcoal adsorption chromatography and Bondesil chromatography. The activity of brassinosteroid was monitored by the rice inclination test and its presence could be confirmed in each purification step. The purified active components were seperated by silica gel adsorption chromatography. The seperated main and minor active brassinosteroid fractions were identified as castasterone and homobrassinolide, respectively, by HPLC. We acknowledge that our work is probably the first report of endogenous brassinosteroid in Perilla frutescense. The content of brassinosteroid in Perilla frutescense as converted into brassinolide was $0.5{\sim}0.8\;ng/g$ fresh weight.

• Computers and Concrete
• /
• v.22 no.6
• /
• pp.551-561
• /
• 2018

The percolation of interfacial transition zone (ITZ) in cementitious materials is of great importance to the transport properties and durability issues. This paper presents numerical simulation research on the ITZ percolation threshold of mortar specimens at meso-scale. To simulate the meso-scale model of mortar as realistically as possible, the aggregates are simplified as ellipsoids with arbitrary orientations. Major and minor aspect ratios are defined to represent the global shape characteristics of aggregates. Some algorithms such as the burning algorithm, Dijkstra's algorithm and Connected-Component Labeling (CCL) algorithm are adopted for identification of connected ITZ clusters and percolation detection. The effects of gradation and aspect ratios of aggregates on ITZ percolation threshold are quantitatively studied. The results show that (1) the ITZ percolation threshold is mainly affected by the specific surface area (SSA) of aggregates and shows a global decreasing tendency with an increasing SSA; (2) elongated ellipsoidal particles can effectively bridge isolated ITZ clusters and thus lower the ITZ percolation threshold; (3) as ITZ volume fraction increases, the bridging effect of elongated particles will be less significant, and has only a minor effect on ITZ percolation threshold; (4) it is the ITZ connectivity that is essentially responsible for ITZ percolation threshold, while other factors such as SSA and ITZ volume fraction are only the superficial reasons.

• Korean Journal of Agricultural Science
• /
• v.48 no.4
• /
• pp.899-910
• /
• 2021

This study was performed to suggest concentration methods leading to the production ofhoney with an excellent flavor by examining the effects of the concentration temperature and method on changes in 5-hydroxymethyl-2-furaldehyde (5-HMF) levels and the flavor components of honey. The 5-HMF contents of honey samples concentrated in a tray concentrator at 45, 50, 60, and 70℃ were 2.1, 2.3, 2.5, and 3.1 mg·kg^-1, respectively, demonstrating that the 5-HMF contents increased as the concentration temperatures were increased. The honey vacuum-concentrated at 70℃ showed a higher 5-HMF content than that at 60℃, similar to the tray-concentrated honey at different temperatures. The main and other minor flavor components of the honey were volatilized and significantly reduced after vacuum concentration. In the tray concentration, all of the honey samples concentrated at 40, 50, 60, and 70℃ showed flavor component patterns similar to each other, and most of the main and other minor flavor components in the honey were volatilized and significantly reduced after tray concentration. As such, most of the main and other minor flavor components of the honey were mostly removed at 70℃ after both the vacuum concentration and tray concentration processes. The effects of the concentration method and temperature on the viscosity, 5-HMF level, and flavor components of the honey were found to be significant in this study. Given that the components of honey were shown to undergo significant physicochemical changes depending on the concentration method used and temperature during laboratory-scale production, the concentration methods devised in this study can be applied industrially.

• Journal of the Korean Applied Science and Technology
• /
• v.9 no.2
• /
• pp.149-156
• /
• 1992

Levels of total lipids in the seeds of three species of the Pinaceae family were determined and their fatty acid compositions were also analyzed by a gas-chromatograph equipped with a capillary column coated with Carbowax 20M. The results are summarized as follows: Lipid contents of the seeds amounted to 56.9% in P. koraiensis, 29.9% in P. thunbergii, and 21.2% in P. rigida. In all lipids 19${\sim}$20 fatty acid were detected and, surprisingly, fatty acids having ${\Delta}^5$-non-methylene interrupted conjugate double bond such as ${\Delta}^{5, 9}-C_{18:2},{\Delta}^{5, 9, 12}-C_{18:3}\;and\;{\Delta}^{5, 11, 14}-C_{20:3}$ occurred in appreciable amounts. In the lipids of P. koraiensis, the main component was $C_{18:2}{\omega}_6(45.0%)$, followed by $C_18:1{\omega} _9(26.9%)$ and ${\Delta}^{5, 9, 12}-C_{18:3}(14.6%)$, and then ${\Delta}^{5, 9}-C_{18:2}(2.2%)$ and ${\Delta}^{5, 11, 14}-C_{20:3}$ were also present. Levels of saturated fatty acid such as $C_{16:0}\;and\;C_{18:0}$ were as low as 7.5%. The seed oil of P. thunbergii predominantly comprised $C_{18:2}{\omega}_6(45.2%)$, and was then occupied by equal amounts ${\Delta}^{5, 9, 12}-C_{18:3}(18.1%)$ and $C_{18:1}{\omega}_9(18.1%)$. Its ${\Delta}^5, 11, 14}-C_{20:3}(5.8%)$ level was the highest in the samples tested. ${\Delta}^{5, 9}-C_{18:2}(2.8%)$ was also detected with other minor components. In the oils from the seeds of P. rigida, $C_{18:2}{\omega}_6$ was present as a main component, accompanied by $C_{18:1}{\omega}_9(21.6%)$ and ${\Delta}^{5, 9, 12}-C_{18:3}(20.3%)$. The latter showed higher level than in any other samples. A minor component corresponding to ${\Delta}^{5, 9, 12, 15}-C_{18:4}$(not confirmed by GC-Mass) occurred in P. thunbergii and P. rigida.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.4
• /
• pp.291-300
• /
• 1990

The lipid compositions including fatty acid sterol lipid class and the lipid component of the total lipid extracted from the flesh of some fresh water fishes I. e. mandarin cornet cat fish and Korean perch were compared. The levels of total lipid of flesh tissues from the fresh water fishes were high(7.4%) in cat fish but low(1.4-2.2%) in mandarin fish Korean perch and cornet fish. On the contrary the content of unsaponifiable matters found in total lipid was low(2.6%) in cat fish but high(6.0%-6.5%) in mandarin fish Korean perch and cornet fish. Total lipids were mainly composed of triglyceride(74.6-86.5%) as major component in each sample and the other lipid components of total lipid e. g. polar lipid free fatty acids and free sterol were the minor components, The major fatty acids in total lipid of each sample were{{{{ {C }_{16 { }:_{ }0 } }}}}(19.6-29.2%) {{{{ {C }_{16 { }:_{ }1 } }}}}(17.3-30.7%) and {{{{ {C }_{18 { }:_{ }1 } }}}}(16.8-29.2%) and additionally it chiefly consisted of {{{{ {C }_{14 { }:_{ }0 } }}}} and {{{{ {C }_{18 { }:_{ }2 } }}}} Particularly the contents of polyenoic acids in total lipid of cat fish were higher than those of the other fish samples. The level of cholesterol in total lipid was low (8.3mg/g) in cat fish but were high(36.9-59.9mg/g) in mandarin fish Korean perch and cornet fish. The contents of fractionated neutral lipid(NL) were higher than those of polar lipid(PL) in each sample. Particularly phospholipid content in PL was low(6.0%) in cat fish but were high(23.1-36.3%) in mandarin fish Korean perch and cornet fish. Neutral lipids were mainly consisted of triglyceride(84.5-93.4%) as amjor component in each sample and the other lipid components of neutral lipid e, g, free fatty acids and free wterol were exhibited as a minor components, The fatty acid compositon of neutral lipids was very resembled to total lipids. The phospholipid in mandarin cornet and cat-fish were mainly composed of phosphatidyl serine(23.1-49.8%) and phosphatidyl choline(20.8-45.3%) The relatively higher amounts of phosphatidyl serine were observed in mandarine cornet and cat-fist than in Korean perch, But phosphatidyl ethanolamine(42.3%) and phosphatidyl choline (49.9%) were the main phospholipid in Korean perch. The extraordinary high content of phos-phatidyl ethanolamine compared to other fishes was characteristics in phospholipid composition of Korean perch. The major fatty acids in phospholipid of each sample were {{{{ {C }_{16 { }:_{ }0 } }}}} (38.3-46.5%) {{{{ {C}_{18 { }:_{ }0 } }}}}(14.2-21.7) and C16:1(11.6-13.8%) and additionally it chiefly consisted of C18:2, C18:0 and C17:0 The major fatty acids in glycolipid of each sample were C16:0(28.8-40.1%) C18:1(5.4-29.9%) C18:0(5.1-28.9%) and C16:1(8.2-20.1%) and additio-nally it chiefly consisted of C14:0 and C20:1.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.37 no.6
• /
• pp.764-771
• /
• 2013

The metal component of Chinese and Korean traditional gold thread was analyzed nondestructively using P-XRF and classified morphologically. In the nondestructive analysis of 22 Chinese and Korean artifacts, there were 10 gold threads made up of Au in China and 7 in Korea; in addition, there were 4 silver threads made up of Ag in Korea and 1 copper thread made up of Cu in China. In the morphological classification, 7 gilt paper strips were confirmed in China and Korea and 4 wrapped threads were identified in China and Korea. Zn, Sn and Fe (minor components of the threads) were detected. These components were assumed to be transferred from the metal found in burial goods.

• Journal of The Korean Astronomical Society
• /
• v.51 no.4
• /
• pp.73-88
• /
• 2018

We present a sample of 54 disk galaxies which have well developed extraplanar structures. We selected them using visual inspections from the color images of the Sloan Digital Sky Survey. Since the sizes of the extraplanar structures are comparable to the disks, they are considered as prominent stellar halos rather than large bulges. A single $S{\acute{e}}rsic$ profile fitted to the surface brightness along the minor-axis of the disk shows a luminosity excess in the central regions for the majority of sample galaxies. This central excess is considered to be caused by the central bulge component. The mean $S{\acute{e}}rsic$ index of the single component model is $1.1{\pm}0.9$. A double $S{\acute{e}}rsic$ profile model that employs n = 1 for the inner region, and varying n for the outer region, provides a better fit than the single $S{\acute{e}}rsic$ profile model. For a small fraction of galaxies, a $S{\acute{e}}rsic$ profile fitted with n = 4 for the inner region gives similar results. There is a weak tendency of increasing n with increasing luminosity and central velocity dispersion, but there is no dependence on the local background density.

• Journal of Environmental Science International
• /
• v.19 no.9
• /
• pp.1161-1167
• /
• 2010

The effects of addition of non degradable polymers, polystyrene (PS) and poly(methyl methacrylate) (PMMA) on the rate of enzymatic degradation of biodegradable poly(l-lactide) (PLLA) have been studied in term of surface structure. Since a component in multicomponent polymeric system has shown surface enrichment, PS and PMMA which have lower surface energy than PLLA were selected as a minor blend component (5 wt%). Enzymatic degradation was carried out at $37^{\circ}C$ and pH 8.5 in the aqueous solution of Proteinase K. Two blend systems, partially miscible (PS/PLLA) and immiscible (PMMA/PLLA), showed the surface enrichment of 4 and 2 times of PS and PMMA, respectively. From the weight loss profile data, the slow degradation rate of both blend films was observed. This indicates that PS or PMMA domains which exist at surface act as a retardant of enzymatic attack.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1998.11a
• /
• pp.125-125
• /
• 1998

Glycyrrhizin (18$\beta$-glycyrrhetic acid $\beta$-D-glucuronyl a-D-glucuronic acid, GL), a main component of liquore extract (Glycyrrhiza glabra), is ingested orally as a component in the oriental medicine. By human intestinal bacteria, glycyrrhizin (18$\beta$-glycyrrhetinic acid $\beta$-D-glucuronyl a-D-glucuronic acid, GL) was metabolized to glycyrrhetinic acid (GA): main pathway metabolizing GL to GA by glucuronidases of Bacteroides J-37 (Kim et al., 1997) and Eubacterium sp strain GLH (Akao et al., 1987) and minor pathway metabolizing GL to GA via 18$\beta$-glycyrrhetic acid D-glucuronic acid (GAMG) by $\beta$-glucuronidase of Streptococcus LJ-22 and glucuronidases of Bacteroides J-37 / E. coli. $\beta$-Glucuronidase from Streptococcus LJ-22 hydrolyzed GL to GAMG, not GA. $\beta$-Glucuronidase of Streptococcus LJ-22 hydrolyzed $\beta$-glucuronic acid conjugates of polysaccharides rather than aglycone-$\beta$-glucuronides Optimal pH of Streptococcus LJ-22 $\beta$-glucuronidase was 5-6 and its molecular weight was 250 kDaltons. Km for GL was 0.37mM.