• Korean Journal of Crystallography
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• v.4 no.1
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• pp.6-10
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• 1993

11 β ,17 β -dihydroxy-9a-fluoro-l7a-methyl androst-4-en-3-one (Fluoxymesterone), CgoH29 FO,, orthorhombic, P2,2,2,, a=13.468(5) A, b= 19.554 (2)A, c=6.578(9)A, a=b=r=90˚, A (CuKa)=1.5406 A , Dm=1.289cm-3, Dc=1.299cm-3 and Z=4 at T=298k. The structure was solved by direct method using seminvariants of ggg Parity group and refined by the full-matrix least-square method, resulting model with reliability factor R=0.069 for 1098 unique reflection over 3σ . Ring A is an 1β-2a-half chair, 5 ring has a highly symmetrical chair conformation, C ring is in a distorted chair conformation and D ring is a 13aenveLope conformation. In the crystal structure, the molecules are packed with a hydrogen bond of 011-H23‥‥03(0.5+x, 1.5-y, 1.0-z) [1.94(9) A of H‥‥0.2.786(9)A of 0‥‥0 and 165(8) ˚ of

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.823-826
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• 1995

The crystal structure of a sulfur sorption complex of the dehydrated partially Co2+ exchanged zeolite A (a=12.058(2) Å) has been determined by single-crystal X-ray techniques. The crystal structure was solved and refined in cubic space group Pm3m at 21(1) ℃. Ion Exchange with aqueous 0.05 M Co(NO3)2 was done by the static method. The crystal of Na4Co4-A was dehydrated at 380 ℃ and 2 × 10-6 Torr for 2 days, followed by exposure to about 100 Torr of sulfur at 330 ℃ for 72 h. Full matrix least-squares refinement converged to R1=0.084 and Rw=0.074 with 102 reflections for which I > 3σ(I). Crystallographic analysis shows that 2.8 Co2+ ions and 4 Na+ ions per unit cell occupy 6-ring sites on the threefold axes. 1.2 Co2+ ions occupy the 8-ring sites on fourfold axes. 2.8 Co2+ ions at Co(1) are recessed 0.66 Å into the large cavity and 4 Na+ ion at Na(1) are recessed 0.77 Å into the sodalite cavity from the (111) plane of O(3)'s. Approximately 16 sulfur atoms were sorbed per unit cell. Two S8 rings, each in a butterfly form, are found in the large cavity. The bond length between S and its adjacent S is 2.27(3) Å. The distance between 6-ring Co2+ ion and its adjacent sulfur is 2.53 (2) Å and that between 8-ring Co2+ ions and its adjacent sulfur is 2.72(9) Å. The angles of S-S'-S and S'-S-S'/ in octasulfur rings are 119.0(2)°and 113.0(2)°, respectively.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.5
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• pp.345-351
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• 2018

A distributed control method is proposed to improve the power sharing performance of bidirectional distributed generators and the voltage regulation performance of a DC bus in a DC microgrid. Voltage sensitivity analysis based on power flow analysis is conducted to analyze the structural characteristics of a DC microgrid. A distributed control method using a voltage sensitivity matrix is proposed on the basis of this analysis. The proposed method uses information received through the communication system and performs the droop gain variation method and voltage shift method without additional PI controllers. This approach achieves improved power sharing and voltage regulation performance without output transient states. The proposed method is implemented through a laboratory-scaled experimental system consisting of two bidirectional distributed generators, namely, a load and a non-dispatchable distributed generator in a four-bus ring-type model. The experimental results show improved power sharing accuracy and voltage regulation performance.

• Molecules and Cells
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• v.43 no.4
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• pp.340-349
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• 2020

Oleoylethanolamide (OEA), a bioactive lipid in bone, is known as an endogenous ligand for G protein-coupled receptor 119 (GPR119). Here, we explored the effects of OEA on osteoclast differentiation, function, and survival. While OEA inhibits osteoclast resorptive function by disrupting actin cytoskeleton, it does not affect receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. OEA attenuates osteoclast spreading, blocks actin ring formation, and eventually impairs bone resorption. Mechanistically, OEA inhibits Rac activation in response to macrophage colony-stimulating factor (M-CSF), but not RANKL. Furthermore, the OEA-mediated cytoskeletal disorganization is abrogated by GPR119 knockdown using small hairpin RNA (shRNA), indicating that GPR119 is pivotal for osteoclast cytoskeletal organization. In addition, OEA induces apoptosis in both control and GPR119 shRNA-transduced osteoclasts, suggesting that GPR119 is not required for osteoclast apoptosis. Collectively, our findings reveal that OEA has inhibitory effects on osteoclast function and survival of mature osteoclasts via GPR119-dependent and GPR119-independent pathways, respectively.

• International Journal of Korean Welding Society
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• v.1 no.1
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• pp.58-62
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• 2001

The surface of AC8A Ah alloy was modified by adding the Cu powder using a Plasma Transferred Arc (PTA) welding process. Under the optimum fabricating conditions, the modified surface of AC8A Ah alloy was observed to possess the sound microstructure with a minimum porosity. Hardness and wear resistance properties of the as-fabricated alloy were compared with those of the 76 heat-treated one. In case of the as-fabricated alloy, the hardness of the modified layer was twice that of the matrix region. Although significant increase in the hardness of the matrix region was observed after T6 heat treatment, the hardness of the modified layer was not observed to change. The wear resistance of the modified layer was significantly increased compared to that of the matrix region. The microstructure of a weld zone and the matrix region were investigated using the optical microscope, scanning electron microscope (SEM), electron probe microanalysis (EPMA), and transmission electron microscope (TEM). The primary and eutectic silicon in the weld zone were finer and more curved than in the matrix region, while some precipitates has had been found therein. According to the TEM observation, the predominant precipitate present in the weld zone was the $\theta$'phase, which is precipitated during cooling by rapid solidification in PTA welding process. Improvement of hardness and wear properties in the weld zone in the as-fabricated condition can be explained based on the presence of $\theta$’precipitates and fine primary and eutectic silicon distribution.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.3
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• pp.82-91
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• 1996

This is a basic study for the static and dynamic analysis on the elasto-plastic and elasto-viscoplastic of an axi-symmetric shell. The objective of this study was to investigate the mechanical characteristics of a nuclear reinforced concrete containment structure, which was selected as a model, by a numerical analysis using a finite element method. The structure was modeled with discrete ring elements of 8-noded isoparametric element rotating against the symmetrical axis, and the interaction between the foundation and the structure was modeled by Winkler's model. Also, the meridional tendon was modeled with 2-node truss elements, and the hoop tendon was done with point elements in two degrees of freedom. The effect of the tendon was considered without the increasement in total degree of freedom as the stiffness matrix of modeled tendon elements was assembled on the stiffness matrix of ring elements linked with the tendon. The results obtained from the analysis of an example were summarized as follows : 1. The stresses in the hoop direction on the interior and exterior surfaces of the structure were shown in changes of similar trend, and high stresses appeared on the structure wall 2. The stresses in the meridional direction on the interior and exterior surfaces were shown in change of different trend. Especially, the stresses at the junctions between the dome and the wall and between the wall and the bottom plate of the structure were very high, compared with those at other parts of the structure. 3. The stress changes in the direction of thickness on the crown of the dome were much linearly distributed. However, as the amount of tendon increased, the stresses in the upper and lower parts of the wall established with the tendon were shown stress concentration. 4. The stress changes in the direction of thickness on the center of the structure wall was linearly distributed in the all cases, and special stress due to the use of the tendon was not shown.

• Korean Journal of Optics and Photonics
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• v.33 no.3
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• pp.106-112
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• 2022

A two-dimensional optical code division multiple access (OCDMA) encoder/decoder, which is composed of add/drop filters and all-pass filters for delay operation, is proposed. An example design is presented, and its feasibility is illustrated through numerical simulations. The chip area of the proposed OCDMA encoder/decoder could be about one-third that of a previous OCDMA device employing delay waveguides. Its performance is numerically investigated using the transfer-matrix method combined with the fast Fourier transform. The autocorrelation peak level over the maximum cross-correlation level for incorrect wavelength hopping and spectral phase code combinations is greater than 3 at the center of the correctly decoded pulse, which assures a bit error rate lower than 10^-3, corresponding to the forward error-correction limit.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1958-1961
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• 2004

Ring Laser Gyroscopes used as navigational sensors inherently experience a lock-in region, where very low rotational rates are not measurable. Most RLG manufacturers use a mechanical dither motor that applies a small oscillatory rotational motion larger than this region to resolve this problem. Any input acceleration that bends this dithering axis causes flexure error, which is a noncommutative error that can not be compensated by simply using integrated gyro sensor output. This paper introduces noncommutative error equations that define attitude errors caused by flexure errors. In this paper, flexure error is classified as sensor level error if the sensing axis coincides with the dithering axis and as system level error if the two axes do not coincide. The relationship between gyro output and the rotation vector is introduced and is used to define the coordinate transformation matrix and angular motion. Equations are derived for both sensor level and system level flexure error analysis. These equations show that RLG based INS attitude error caused by flexure is directly proportional to time, amount of input acceleration and the dynamic frequency of the vehicle.

• Economic and Environmental Geology
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• v.21 no.4
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• pp.335-348
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• 1988

The author aimed to describe the volcano-stratigraphy and petrology of the volcanic mass in the Koheung peninsula, South Cheolla province. The volcanic mass is composed of the volcanics and intrusives of late Cretaceous which extruded the Pre-cambrian metamorphic(Jirisan gneiss complex) and the early Cretaceous sedimentary(Duwon Formation) basement. The volcanic pile consists of, in ascending order, Bibongsan andesite, Koheung tuff and breccia, and Palyeongsan welded tuff, and are intruded by ring intrusives( intrusive breccia, andesite porphyry, intrusive rhyolite and fine-grained quartz-diorite) and central pluton(diorite, quartz monzodiorite, biotite granite and micrographic granite). Bibongsan andesite mainly consists of andesite tuff and lava. Koheung tuff consists of alternation of fine tuff, coarse tuff and lapilli tuff, and Palyeongsan welded tuff which overlies Koheung tuff, comprises K-feldspar and quartz phenocrysts, elongated brown fiamme, lithic fragments in matrix of devitrified brown glass shards, and mainly consists of rhyodacite to rhyolite vitric ash-flow tuff. The results of petrochemical studies of the igneous rocks suggest that the rocks were a serial differentiational products of fractional crystallization of calc-alkaline magma series. This study reveals that the volcanic mass in this area is inferred to the remnant of the resurgent cauldron, measuring 30 by 25 km in diameter. The cauldron block was lowered at least 1,000 m by ring fault displacement.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.174-181
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• 1996

The novel synthesis of 3-aminopropyl dihydrogen phosphate(3-APPA; 3-Aminopropane phosphoric acid), and its applicability to the skin as a cosmetic raw material in terms of its efficacy and toxicology were presented. The phosphorylation of 3-amino-1-propanol was carried out via cyclization into 6-membered 2, 6-oxaza-phosphoryl ring in the presence of phosphorous oxychloried and an organic base. The subsequent ring-opening hydrolysis and crystallization afforded the highly purified product in 90% isoloated yield. The method is much superior to the previous literature phosphorylation methodsm, as the procedure is simple and high-yielding. To confirm the efficacy of 3-APPA, several activities related to anti-aging capacity were measured. In-vitro human fibroblast, linear and 3-dimensional collagen matrix culture revealed that 3-APPA stimulated the proliferation of fibroblasts, and enhanced the synthesis of collagen, which showed 3-APPA's potency for skin wrinkle reduction. The toxicolgical aspect of 3-APPA was also extensively examined. In vivo toxicity tests such as acute oral toxicity, eye irritation, human patch, and the repeat insult human patch test proved 3-APPA to be a safe material. Thus 3-APPA can be used as an effective anti-aging agent for various cosmetic formulations.