• Journal of Korea Foundry Society
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• v.37 no.4
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• pp.115-122
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• 2017

The aim of this research is to evaluate the wear properties of (TiB+TiC) paticulate reinforced titanium matrix composites (TMCs) by in-situ synthesis. Different particle sizes (1500, $150{\mu}m$) and contents (0.94, 1.88 and 3.76 mass% for Ti, 1.98 and 3.96 mass% for the Ti6Al4V alloy) of boron carbide were added to pure titanium and to a Ti6Al4V alloy matrix during vacuum induction melting to provide 5, 10 and 20 vol.% (TiB+TiC) particulate reinforcement amounts. The wear behavior of the (TiB+TiC) particulate reinforced TMCs is described in detail with regard to the coefficient of friction, the hardness, and the degree of reinforcement fragmentation during sliding wear. The worn surfaces of each sliding wear condition are shown for the three types of wear studied here: transfer layer wear, particle cohesion wear and the development of abrasive areas. The fine reinforcements of TMCs were easily fragmented from the Ti matrix as compared to coarse reinforcements, and fragmented debris accelerated the decrease in the wear resistance.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.778-784
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• 2003

N'-(1-alkyl-2,3-dihydro-2-oxo-1H-3-indolyliden)-4-pyridinecarboxylic acid hydrazide derivatives, 3(a-g), were synthesized in a trial to overcome the resistance developed with the therapeutic uses of isoniazid (INH). The lipophilicity of the synthesized derivatives supersedes that of the INH as expressed by Clog p values. The synthesized compounds and INH were tested against bovin, human sensitive and human resist strains of Mycobacterium tuberculosis. Compounds 3a, 3d, 3f and 3g with 1-unsubstituted, 1-propyl, 1-propynyl and 1-benzyl groups respectively exhibited equipotent growth inhibitory activity (MIC 10 $\mu$mol) against the tested strains as compared with INH however the later has no activity against human resist strain. Pharmacokinetic study revealed that the rate and extent of absorption of the tested derivatives (3d and 3f) significantly higher than that of INH (p＜0.05). The relative bioavailabilities ($F_R%$) were 183.15 and 443.25 for 3f and 3d respectively as compared to INH. These results preliminary indicate the possible use of the prepared derivatives for treatment of tuberculosis infections in order to overcome the resistance developed with INH.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3629-3634
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• 2012

A series of new 4-(pyridin-4-yl)-(3-methoxy-5-methylphenyl)-1H-pyrazoles (6a-k & 7a-l) has been rationally designed based on the structure of the lead compound KIST301080, a selective ROS receptor tyrosine kinase inhibitor, in order to study the activity of ROS of this new class of inhibitors. The compounds were synthesized and screened against ROS kinase, where compound 6h showed moderate inhibitory activity with an $IC_{50}$ value of $6.25{\mu}M$. The study emphasized the importance of the acetonitrile group at the pyrazole ring and also the importance of having a hydrogen bond donor on the distal phenyl ring linked to the pyridine moiety.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1021-1025
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• 2009

A novel supramolecular network containing binuclear copper unit $[Cu(phen)_{2}({\mu}-ID\;A)Cu(phen){\cdot}(NO_{3})](NO_{3}){\cdot}4(H_{2}O)$ (1) was synthesized through the self-assembly of iminodiacetic acid ($H_2IDA$) and 1,10-phenanthroline (phen) in the condition of pH = 6. It has been characterized by the infrared (IR) spectroscopy, elemental analysis, single crystal X-ray diffraction, and thermogravimetric analysis (TGA). 1 shows a 2-D supramolecular structure assembled through strong and unique $\pi-\pi$ packing interactions. Density functional theory (DFT) calculations show that theoretical optimized structures can well reproduce the experimental structure. The TGA and powder X-ray diffraction (PXRD) curves indicate that the complex 1 can maintain the structural integrity even at the loss of free water molecules. The magnetic property is also reported in this paper.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1118-1120
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• 2009

Micro-size CdS spheres of hollow shape were fabricated through the self-assembly of high density arrow-like nanorods. The synthesis of the CdS hollow spheres were accomplished in an aqueous solution of cadmium nitrate and triblock copolymer (Pluronic P123) at low temperature (80 ${^{\circ}C}$) through the slow release of S2- ions from thioacetamide. Morphology of the fabricated CdS hollow spheres was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results indicate that the arrow-like CdS nanorods are simultaneously grown and attached each other to form the building units that become the spheres with hollow inside as a self-assembled process. The CdS spheres have a diameter of $2{\sim}3 {\mu}m$ and consist of the nanorods with a length of$\sim$800 nm. The nanocrystal building blocks have a hexagonal CdS structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.422-425
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• 1999

Ultrafine NiO/YSZ (Yttria-Stabilized Zirconic) composite powders were prepared by using a glycine nitrate process (GNP) for anode material of solid oxide fuel cells. The specific surface areas of synthesized NiO/YSZ composite powders were examined with controlling pH of a precursor solution and the content of glycine. The binding of glycine with metal ions occurring in the precursor solution was analyzed by using FTIR. The characteristics of synthesized composite powders were examined with X-ray diffractometer, a BET method with $N_2$ absorption, scanning and transmission electron microscopies. Strongly acid precursor solution increased the specific surface area of the synthesized composite powders. This is suggested to be caused by the increased binding of metal ions and glycine under a strong acid solution of pH=0.5 that lets glycine consist of mainly the amine group of NH$_3$$^{+}$ After sintering and reducing treatment of NiO/YSZ composite powders synthesized by GNP, the Ni/YSZ pellet showed ideal microstructure very fine Ni Particles of 3-5${\mu}{\textrm}{m}$ were distributed uniformly and fine pores around Ni metal particles were formed, thus, leading to an increase of the triple phase boundary among gas, Ni and YSZ.Z.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.44-49
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• 2003

$\alpha$-MSH plays an important role in UV induced melanogenesis in human skin. It is believed to exert its effects by binding to $\alpha$-MSH receptor that in turn activates adenylate cyclase and increase melanocyte proliferation, dendricity and melanogenesis. In this study, we evaluated plant extracts showing the inhibitory activity on $\alpha$-MSH induced melanogenesis. The Cnidium officinale extracts showed high inhibitory activity on $\alpha$-MSH induced melanogenesis. It ($50{\mu}\textrm{g}$/ml) inhibited the melanin synthesis activated by $\alpha$-MSH in B-16 melanoma cells. Also, we isolated active compound from C. officinale extracts by Mass spectrophotometer, HPLC. It was identified as Senkyunolide A. It showed the same inhibitory activity as C. officinale extracts at the lower concentration. Finally, Senkyunolide A from Cnidium officinale extracts could playas $\alpha$-MSH antagonist and be used as a strong ingredient for skin whitening cosmetics.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.5
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• pp.585-591
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• 2006

We report a novel HPLC method for analyzing the capsaicinoids and nonivamide. The following conditions were used: a total column and column temperature of $3^{\circ}C$, a detection wavelength of 280 nm, an eluent containing acetonitrile : 0.5% formic acid(31:69, v/v). The experimental data was compared with standard nonivamide and capsaicin. The results showed that nonivamide was eluted in 96.7 minutes with a recovery ratio of 96.5% after adding known nonivamide. In addition, the detection limit for nonivamide was 18.6 ng. The capsaicinoids from Korean pepper were extracted (after blooming 60th) from 3 breeds cultivated in Korea, Buchon, Chungyang and Hanbando. and crisis it analyzed sympathizes the nonivamide in the result nonivamide from the Buchon and the Chungyang which are not detected from the Hanbando $0.16{\sim}0.24{\mu}g/g$ it detects with very small amount it contains it confirmed the each capsaicinoid with the HPLC and the LC-MS. These results are expected contribute to the quality control of various product processes, which includes product delivery inspection as well as examining the capsaicinoids present in the product for possible medicine manufacture and various foodstuff, and the nonivamide content, which may be a feed for various manufacturing processes involving chemical synthesis.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2358-2366
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• 2013

Iron oxide (ferrihydrite, hematite, and magnetite) coated silica gels were prepared using a low-cost, easily-scalable and straightforward method as the adsorbent material for arsenic removal application. Adsorption of the anionic form of arsenic oxyacids, arsenite ($AsO^{2-}$) and arsenate ($AsO{_4}^{3-}$), onto hematite coated silica gel was fitted against non-linear 3-parameter-model Sips isotherm and 2-parameter-model Langmuir and Freundlich isotherm. Adsorption kinetics of arsenic could be well described by pseudo-second-order kinetic model and value of adsorption energy derived from non-linear Dubinin-Radushkevich isotherm suggests chemical adsorption. Although arsenic adsorption process was not affected by the presence of sulfate, chloride, and nitrate anions, as expected, bicarbonate and silicate gave moderate negative effects while the presence of phosphate anions significantly inhibited adsorption process of both arsenite and arsenate. When the actual efficiency to remove arsenic was tested against 1 L of artificial arsenic-contaminated groundwater (0.6 mg/L) in the presence competing anions, the reasonable amount (20 g) of hematite coated silica gel could reduce arsenic concentration to below the WHO permissible safety limit of drinking water of $10{\mu}g/L$ without adjusting pH and temperature, which would be highly advantageous for practical field application.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2297-2304
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• 2013

A series of novel benzimidazole derivatives bearing a heterocyclic ring as oxadiazole (21-32), thiadiazole (33-34), triazole (35-36) were synthesized and evaluated for their activities against Coxsackie virus B3 and B6 in Vero cells. Compounds 21-26, 31-36 with moieties of 2'-pyridyl, 3'-pyridyl and 4'-pyridyl at the 2-position and oxadiazoles, thiadiazole, or triazole substituent at the 4- or 5-position generally displayed activities against CVB3 and CVB6. Especially compound 24 ($IC_{50}=1.08{\mu}g/mL$, SI = 61.7 against CVB3) was the promising candidate as lead compound for anti-enteroviral drug. It was observed in the incorporation of heterocyclic rings in benzimidazole at the 5-position could enhance their biological activities.