• Bulletin of the Korean Chemical Society
• /
• v.12 no.2
• /
• pp.189-193
• /
• 1991

A series of compounds that contain varying numbers of the same mesogenic structure, biphenyl p-oxybenzoate unit, attached through a pentamethylene spacer to the central benzene ring were prepared and their liquid crystallinity was studied. The mesophase-forming ability of a dimesogenic compound was found to be greatly dependent on whether or not its geometric shape is linear and also on the existence of the pentamethylene spacer between the mesogen and the central core. The presence of the spacer enhanced the capacity of a compound to form a mesophase. In the trimesogenic compound the mesogens were linked to the 1,3,5-positions of the core benzene ring through the spacer. The compound was found to be enantiotropically nematic.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.3
• /
• pp.281-284
• /
• 1999

Two La1.82Ca1.18Cu2O6+δ (2126) compounds exhibited different properties depending upon how they were synthesized. The compound prepared under high oxygen pressure showed superconductivity. But the compound prepared under low oxygen pressure did not exhibit superconductivity, and showed a metal-insulator transition. Our study on these compounds shows that a small amount of additional oxygen intercalated into the superconducting phase plays an important role for superconductivity. The Fermi surface of non-superconducting 2126 compound possesses nesting phenomena, which is the reason for the M-1 transition. On the other hand, the superconducting 2126 compound does not show Fermi surface nesting. This is because the additional oxygen removes some electrons from Cu d-orbitals, thereby bradking the Fermi surface nesting.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.259.1-259.1
• /
• 2003

In the course of hepatoprotective screening for domestic plants. the aerial parts of B. vulgaris var. cycla exhibited hepatoprotective activity which was determined by using the primary cultures of rat hepatocytes injured by H2O2. Bioactivity-guided separation for this plant gave a new flavonoid (1) and the known compounds (2-4), which structures were elucidated by 1H-NMR, HMQC, 1H-1H COSY and HMBC as compound 1, apigenin 8-C-, 7-O-di-$\beta$-D-glucopyranoside, compound 2, vitexin 2"-O-$\beta$-D-glucopyranoside, compound 3, (+)-dehydrovomifoliol, and compound 4, 3-hydroxy-5$\alpha$, 6$\alpha$-epoxy-$\beta$-ionone.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.160.2-160.2
• /
• 2003

When ginsenoside $R_{b1}$ and $R_{b2}$ were anaerobically incubated with human fecal microflora, these ginsenosides were metabolized to compound K. When ginsenoside $R_{g3}$ was anaerobically incubated with human fecal microflora, the ginsenoside $R_{g3}$ was metabolized it to ginsenoside $R_{h2}$. Among ginsenosides, compound K and 20(S)-ginsenoside $R_h2$ exhibited the most potent cyotoxicity against tumor cells: 50% cytotoxic concentrations of compound K in the media with and without fetal bovine serum (FBS) were 27.1 - 31.6 mM and0.1 - 0.6 mM, and those of 20(S)-ginsenoside $R_h2$ were 37.5 $\rightarrow$ 50 and 0.7 - 7.1 mM mM, respectively. (omitted)

• Current Optics and Photonics
• /
• v.6 no.4
• /
• pp.359-366
• /
• 2022

In this paper, we present a new design for angle-sensitive pixels (ASPs). The proposed ASPs take advantage of subwavelength compound gratings to capture the light angle, which enables pixel size to reach the wavelength scale of 0.7 ㎛ × 0.7 ㎛. The subwavelength compound gratings are implemented by the wires of the readout circuit inherent to the standard complementary metal-oxide-semiconductor manufacturing process, thus avoiding additional off-chip optics or post-processing. This technique allows the use of two pixels for horizontal or vertical angle detection, and can determine the light's angle in the range from -45° to +45°. The proposed sensor enables surface-profile reconstruction of microscale samples using a lensless imaging system.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.808-813
• /
• 2022

This study presents the problems of data imbalance, varying difficulties across target objects, and small objects in construction object segmentation for far-field monitoring and utilize compound loss functions to address it. Construction site scenes of assembling scaffolds were analyzed to test the effectiveness of compound loss functions for five construction object classes---workers, hardhats, harnesses, straps, hooks. The challenging problem was mitigated by employing a focal and Jaccard loss terms in the original loss function of LinkNet segmentation model. The findings indicates the importance of the loss function design for model performance on construction site scenes for far-field monitoring.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.2
• /
• pp.112-122
• /
• 1995

While many surfaces such as automobile outer panels, ship hulls and airfoils are characterized by their smooth, free-form shapes, a far larger class of functional surfaces are characterized by highly irregular, multi-featured shapes consisting of pockets, channels, ribs, etc. In constaract to the design of aesthetic, free-form surfaces, functional surface design can perhaps best be viewed as a process of assembling a collection of known component surfaces to form a single compound surface. In this paper, we presents a feature-based functional surface modeling method. A single feature involves a secondary surface, which we must join to a primary surface with a smooth transition between two boundary courves. Through recursive blending of a secondary surface with the primary surface, the mullti-featured surface is represented. After constructing a compound surface, we generate the Z-map for NC machining of the surface. Offsetting the Z-map using the inverse offsetting technique, we get CL tool paths with out gouging.

• Proceedings of the Korea Society of Environmental Biology Conference
• /
• 2002.05a
• /
• pp.46-46
• /
• 2002

• Journal of Ginseng Research
• /
• v.42 no.2
• /
• pp.229-232
• /
• 2018

• YAKHAK HOEJI
• /
• v.19 no.1
• /
• pp.16-20
• /
• 1975

A polyacetylenic compound ws isolated from the subterranean parts of Bupleurum falcatum L. (Umbelliferae) and its structure was elucidated as pentadecadiene-(2, 9)-diyn-(4, 6)-ol(1) acetate.