• Bulletin of the Korean Chemical Society
• /
• v.16 no.6
• /
• pp.518-523
• /
• 1995

New square planar nickel(Ⅱ) complexes with various 1-alkyl (4a-4c) and 1-hydroxyalkyl (4d-4f) derivatives of the 14-membered pentaaza macrocycle 8-ethyl-8-nitro-1,3,6,10,13-pentaazacyclotetradecane have been synthesized by two-step metal template condensation reactions of ethylenediamine, nitroethane, formaldehyde, and appropriate primary amines. The nitro group and/or hydroxyl group of 4a-4f are not directly involved in the coordination. The nickel(Ⅱ) complexes exist in coordinating solvents such as MeCN, Me2SO, and H2O as equilibrium mixtures of the square planar [Ni(L)]2+(L=4a-4f) and octahedral species [Ni(L)S2]2+(S=solvent molecule). Although the ligand field strength and redox potentials of the complexes are not affected by the nature of the substituents, the formation of octahedral species for 4d-4f in MeCN is strongly restricted by the hydroxyl group. Synthesis, characterization, and solution behaviors of the nickel(Ⅱ) complexes are described.

• Korean Journal of Soil Science and Fertilizer
• /
• v.29 no.1
• /
• pp.44-52
• /
• 1996

Humic substances of 17 organic fertilizers available on the market were the objects of study. The list of ingredients for formulation of them comprised fish meal. bone meal, oil-cakes, brewer's grains, peat, sawdust, wood bark, zeolite, soil conditioner, live-stock droppings, amino acid fermentation byproduct, chaff, limestone and others. Humic and fulvic acids were isolated from those substances and given chemical and spectroscopic analyses. Nutritional values of the organic fertilizers showed big diversity. Humification of organic matter was incomplete for some of the fertilizers as indicated by a high C/N ratio. Extractable humic acid percentage was higher, in general, than that of fulvic acid. Also the relative content of humin increased with advanced humification. Total acidity was closely related to phenolic hydroxyl groups. Relationships between carboxyl and hydroxyl groups. and carboxyl and alcoholic hydroxyl groups were very significant. Ultraviolet and visible light absorption spectra of humic and fulvic acids were substantially similar. The types of humic acids were B. P, and Rp. Two humic acids of the 17 samples belonged to B type. 3 to P type and all the rest to Rp type.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.3
• /
• pp.27-33
• /
• 2000

The selective chemical vapor deposition techniques for Cu metallization were studied. For enhancing the selectivity, furnace annealing and N$_{2}$ plasma were treated on patterned TiN/BPSG prior to the copper deposition. As a result, Cu did not deposited lead to suppressing the nucleation on BPSG singificantly. With the increasement the plasma treatment temperature, copper nucleation on BPSG was suppressed mote effectively, From TOF-SIMS(Time-of-Flight Secondary ion Mass Spectrometry), it is considered that annealing and N$_{2}$ plasma treatment remove hydroxyl(0-H) group so that eliminating the nucleation site for copper precursor enhance the selectivity.

• Journal of Photoscience
• /
• v.4 no.3
• /
• pp.133-140
• /
• 1997

A system for studying oxidative hemolysis has been used by controling UV-irradiation and concentration of a novel molecular probe, N,N'-bis(2-hydroperoxy-2-methoxyethyl)-1,4,5,8-naphthalenetetra-carboxylic diimide (NP-III), which generates hydroxyl radical upon longer wavelength photoirradiation (> 350 nm). NP-III induces 25~30% of hemolysis at low concentration (50 $\mu$M) for 3h-irradiation of UVA. The simultaneous treatment of N-ethylmaleimide (NEM) with NP-IH completely hemotyzed erythrocytes under the same conditions as NP-III alone by both decreasing thiol group and increasing lipid peroxidation in erythrocyte membrane. However. thiol-reducing agents prevented the protein-crosslinking and lipid peroxidation on the NEM-synergistic hemolysis by partially scavenging hydroxyl radical and maintaining the thiol group of erythrocyte membrane in the reduced state. In addition, erythrocytes pretreated with 2,2,5,7,8-pentamethyl-6-hydroxychromane (PMC), vitamin E homologue was able to delay and decrease the lipid peroxidation when compared to cells pretreated with both NEM and PMC. We suggest that the presence of reduced thiols in inner membrane protein by GSH can prevent the protein-crosslinking and the lipid peroxidation, and eventually prevent the oxidative hemolysis of erythrocyte.

• Journal of the Korean Wood Science and Technology
• /
• v.22 no.2
• /
• pp.54-60
• /
• 1994

The pine bark from mechanical pulp industry was cooked with bisulfite liquor, and the chemical and physical properties of the spent liquor after cooking for 90 minutes, which allowed partial defibration were determined. Lignosulfonate or lignin-related materials in the spent liquor have a molecular weight of approximately 3,000, which is lower than that of commercial lignosulfonate (C-LS) prepared from wood. The sulfonic equivalent weight calculated by colloid titration was 307 for C-LS, 238~239 for spent liquor. The contents of lignosulfonic acid and phenolic hydroxyl groups on $C_9$ unit of lignin in the spent liquor were 0.98~0.99, and 1.51~1.66, respectively. These values were remarkably higher than those of C-LS. Especially the content of phenolic hydroxyl group was almost twice that of C-LS. The viscosity of spent liquor after freeze drying was very low compared to C-LS. The dispersing ability of spent liquor was almost equivalent to or more than that of C-LS.

• Korean Journal of Metals and Materials
• /
• v.46 no.10
• /
• pp.662-671
• /
• 2008

The behavior of hydrogen in the steel making process was investigated. The relation between the composition of ladle slag and hydrogen concentration in molten steel was considered. The hydrogen distribution ratio between ladle slag and molten steel was increased with increasing basicity of the slag; it was about 20 when the basicity of slag was 15. Hydroxyl capacity measured from the hydrogen distribution ratio between slag and the molten steel was comparatively corresponding to the value of hydroxyl capacity measured by the equilibrium reaction of slag and $H_2O$ gas. However, it is considerably different from the value calculated by regular solution model. The influence of hydrogen on a sticking type breakout is considered. The effect of hydrogen and $H_2O$ gas on the crystallization behavior of mold powder was investigated by DHTT (Dual hot thermocouple technique). As a result, it was proved that mold powder could be crystallized by $H_2O$ gas in the atmosphere. Therefore, it is concluded that $H_2O$ gas in the atmosphere can be a possible cause of the sticking type breakout that occasionally occurs in the continuous casting process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.8
• /
• pp.607-614
• /
• 2007

This paper investigated that the functional group and chemical structure of additives affect ice adhesion in aqueous solutions cooling with stirring. In order to compare the effect on the ice adhesion in aqueous solutions, the functional group like carboxyl (-COOH), hydroxyl(-OH) or amine($-NH_{2}$) one were compared each other. Among the functional group, the strength of the hydrogen bonding force order is amine, hydroxyl and carboxyl one. It supports that ethylene diamine 7 mass% solution including amine group was effective to suppress the ice adhesion, though it is corrosive. Also, the ice adhesion were effectively resisted and formed lots of ice slurries in cooling experiment of 7 mass% solution of 1, 2-and 1, 3-propanediol which is different molecular structure but equal molecular weight each other.

• Journal of Periodontal and Implant Science
• /
• v.41 no.6
• /
• pp.263-272
• /
• 2011

A number of surface modification techniques using immobilization of biofunctional molecules of Titanium (Ti) for dental implants as well as surface properties of Ti and Ti alloys have been developed. The method using passive surface oxide film on titanium takes advantage of the fact that the surface film on Ti consists mainly of amorphous or low-crystalline and nonstoichiometric $TiO_2$. In another method, the reconstruction of passive films, calcium phosphate naturally forms on Ti and its alloys, which is characteristic of Ti. A third method uses the surface active hydroxyl group. The oxide surface immediately reacts with water molecules and hydroxyl groups are formed. The hydroxyl groups dissociate in aqueous solutions and show acidic and basic properties. Several additional methods are also possible, including surface modification techniques, immobilization of poly(ethylene glycol), and immobilization of biomolecules such as bone morphogenetic protein, peptide, collagen, hydrogel, and gelatin.

• Macromolecular Research
• /
• v.8 no.3
• /
• pp.125-130
• /
• 2000

Resorcinol formaldehyde resins are synthesized by polycondensation of resorcinol with formal-dehyde and have various structures by the condensation type. The influence of polycondensation type on the stability and structure of the resorcinol formaldehyde resin was studied by molecular mechanics and molecular dynamics. The resins formed by 2,6-polycondensation and 4,6-polycondensationwith head-to-tail orientations have structures of intramolecular hydrogen bonds between 1-hydroxyl groups and between outer hydroxyl groups of the adjacent resorcinols, respectively. The resin formed by 2,6-polycon-densation with head-to-head orientation has a structure that inner hydroxyl groups cluster in the center of the molecule. Energetical stability of the resin is affected by both the intramolecular hydrogen bonds and the steric' hindrance by phenyl group.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.2
• /
• pp.197-201
• /
• 1998

The complex formation from Cu(Ⅱ) ion and 1,3-bis(tris(hydroxymethyl)methylamino)propane (bistrispropane) in aqueous solution has been studied potentiometrically and spectrophotometrically. Bistrispropane (btp) coordinates to Cu(Ⅱ) as multidentate. In the btp (L) complex CuL2+, two of the hydroxyl oxygen atoms as well as the amine nitrogens of the ligand are coordinated. In neutral and weakly acidic media, one of the coordinated hydroxyl groups is deprotonated. In basic media, an additional hydroxyl group undergoes deprotonation. The equilibrium constants for the formation of CuL2+, CuLH-1+, and CuLH-2 have been determined. The nature of the coordinate bonds has been deduced from the potentiometric data and the spectra of these complexes.