• Journal of the Korean Chemical Society
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• v.38 no.4
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• pp.288-294
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• 1994

Several new nickel(II) complexes, [Ni(L)X$_2$ and [Ni(L)$_2$]Cl$_2$ (L = L$_1$, L$_2$ ; X = Cl$^-$, Br$^-$, I$^-$) have been synthesized by reacting NiX$_2$ or NiX$_2$, 6H$_2$O with aminophosphines(L) wherein L is 1,2-bis{(diphenylphosphino)amino}propane(L$_1$) or 1,2-bis{(diphenylphosphino)amino}ethane(L$_2$). These complexes are characterized by the optical spectroscopic methods (UV/Vis, CD, IR, $^1$H-NMR, and $^{31}$P-NMR) together with conductometer and elemental analysis. The complex with I$^-$ is tetrahedral, where the complexes with Cl$^-$ or Br$^-$ are square planar. The complexes, [Ni(L)X$_2$](X = Cl$^-$, Br$^-$) become tetrahedral, as they react with methyl iodide. The Ni(L)X$_2$ complexes underwent solvolysis with a various organic solvents such is EtOH, DMSO, THF and DMF.

• Clean Technology
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• v.11 no.3
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• pp.129-139
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• 2005

Fluoride-type cleaning agents such as TFEA (2,2,2-trifluoroethanol) and HFE (hydrofluoroether) are noticed to be next generation cleaning agents alternative to CFCs since they do not destruct ozones in the stratosphere due to no containment of chloride in the molecule, have lower global warming potential compared to HFCs and HCFCs, and are thermally stable compounds. Thus, the physical properties and cleaning agents were measured and compared with those of CFC-113, 1,1,1-TCE and HCFC-141b which are ozone destruction substances. They were also compared and evaluated with those of IPA and methanol which are currently employing as alternative cleaning agents. And TFEA-based cleaning agents consisted of TFEA and alcohols or HFEs were formulated, their physical properties and cleaning abilities were measured and their utilization as alternative cleaning agents was evaluated. As a result, TFEA and HFEs have lower cleaning ability for their removal of various soils compared to chloride-type cleaning agents, but theyshow excellent cleaning ability for Fluoride-type soils. And it is observed that the formulated cleaning agents of TFEA and alcohols or HFEs caused to increase cleaning ability of flux and unsoluble cutting oil more than 100% compared to their individual component. Therefore, the fluoride-type cleaning agents are expected to be utilized for development of environmental-friendly non aqueous cleaning agents with excellent cleaning ability if they are formulated with proper solvents or additives.

• Safety and Health at Work
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• v.2 no.3
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• pp.210-217
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• 2011

Objectives: The purpose of this study was to measure the concentration of volatile organic compound (VOC)s originated from the chemicals used and/or derived from the original parental chemicals in the photolithography processes of semiconductor manufacturing factories. Methods: A total of four photolithography processes in 4 Fabs at three different semiconductor manufacturing factories in Korea were selected for this study. This study investigated the types of chemicals used and generated during the photolithography process of each Fab, and the concentration levels of VOCs for each Fab. Results: A variety of organic compounds such as ketone, alcohol, and acetate compounds as well as aromatic compounds were used as solvents and developing agents in the processes. Also, the generation of by-products, such as toluene and phenol, was identified through a thermal decomposition experiment performed on a photoresist. The VOC concentration levels in the processes were lower than 5% of the threshold limit value (TLV)s. However, the air contaminated with chemical substances generated during the processes was re-circulated through the ventilation system, thereby affecting the airborne VOC concentrations in the photolithography processes. Conclusion: Tens of organic compounds were being used in the photolithography processes, though the types of chemical used varied with the factory. Also, by-products, such as aromatic compounds, could be generated during photoresist patterning by exposure to light. Although the airborne VOC concentrations resulting from the processes were lower than 5% of the TLVs, employees still could be exposed directly or indirectly to various types of VOCs.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.403-411
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• 2009

This study was performed to propose appropriate conditions suited to the analysis of naphthalene by comparing desorption efficiencies under various conditions. 1. As to influence by adsorbing media and desorbing solvent on desorption efficiency of naphthalene, when adsorbed by CCT, o-xylene gave the highest desorption efficiency of $73.96{\pm}0.53%$ while the lowest of $1.14{\pm}0.03%$ desorbed by ether. Both XAD-2 and Chromosorb 106 showed around 90% of desorption efficiencies for each solvent, especially desorption efficiencies more than 95% were achieved when adsorbed by Chromosorb 106 and desorbed by $CS_2$ or o-xylene. 2. Desorption efficiencies descended over the storage period in any condition(p<0.05). For all three adsorbing media, while desorption efficiencies showed no significant difference(p>0.05) between room temperature and refrigeration a day of loading, samples kept in room temperature had higher desorption efficiencies than refrigerated ones in 7 and 14 days with significant difference(p<0.05).Also, desorption efficiencies dropped drastically in 7 days, from that point the decreasing tendency went mild. 3. When respective 1 TLV and 0.1 TLV of naphthalene were spiked on CCT and desorbed by CS2($46.45{\pm}0.59%$ vs. $30.15{\pm}0.81%$), o-xylene($73.96{\pm}0.53%$ vs. $67.51{\pm}1.34%$), and ether($1.14{\pm}0.03%$ vs. N.D.) desorption efficiencies increased as the amount of loading increased(p<0.05).On the other hand, naphthalene spiked on XAD-2 and Chromosorb 106 indicated no significant difference(p>0.05) in desorption efficiencies between 1 TLV and 0.1 TLV. In conclusion, in order for favorable desorption efficiencies of naphthalene it is important to select appropriate adsorbing media and desorbing solvent accordingly. The result revealed that adsorbing media of XAD-2 and Chromosorb 106 outperformed CCT and desorbing solvents of $CS_2$ and o-xylene achieved over 90% of desorption efficiencies when adsorbed on XAD-2 and Chromosorb 106. Also, considering the tendency that desorption efficiencies of naphthalene decrease with time, the samples should be analyzed as soon as possible.

• Journal of Preventive Medicine and Public Health
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• v.10 no.1
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• pp.16-24
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• 1977

This is a result of clinical examination for workers working with Chromic acid and Chromium compounds in the plating room of their companies. I selected two companies that the plating process and the kinds of plating were similar. One (SW Co.) was more or less improved the operating environment with the ventilation machine so on and another (SR Co.) did not it so. The former was examined at March 29th 1977, the latter was at June 28th 1976. But the respiratory communicable diseases, flue or common cold so on were not spreaded there at that time. The clinical aspects were compared between the group of SW, and SR. The swelling and hyperemic signs of nasal mucous membrane and the experience of nasal bleeding were about 50%, generally, in all the groups. The following problem was dizziness or vertigo. The nasal signs in the group of SW (improved ventilation of the room air) were relatively weak, but in another, it was some what severe; - there was necrotic sign with thick nasal clast. They were only used of gauze mask when the vapors of various solvents were deeply full in the room. And there was very high rate of bronchial signs, sputum or coughing in the group of SW improved ventilation so called, than another one. I suppose that it means chronic inflammatory change of the bronchial mucous membrane with deeper signs, due to the individual protectors were carelessly or not used according to the improving of the operating environment. Theses nasal signs mentioned the above were not nearly in the other groups had not been done the Chromium plating. The Status of RBC, Hb and Ht, of urine protein and urobilinogen were mostly in normal range. But the number of WBC was more or less showed with a positive correlation to the working duration.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.95-100
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• 2005

The using amount of preservative-treated wood equipments has been increased. Specially, chromate copper arsenate (CCA) has been widely used to exterior wood. We are faced to the disposal problem after service period of CCA treated wood due to its toxic heavy metals. For the disposal of end-used treated wood, land-filling and incinerating methods are mainly applied. The essential problem of incinerating is an arsenic release into atmosphere. Low pyrolysis is suggested as the methods of protecting arsenic release during incineration. The heavy metals were recovered after combustion of the treated wood at the low temperature which arsenic can not released. The recovery amounts of effectiveness compounds was determined in various solvents (citric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid) and different temperature (300, 400, $500^{\circ}C$). The higher temperature was applied, the more copper was recovered. The chromium was difficult to be recovered on the carbonized CCA treated wood at 0.5% acid concentration. The recovery mass of arsenic decreased on the higher combustion treated wood. The recovery of chromium was difficult due to the chemical change of the chromium arsenate during pyrolysis.

• Korean journal of food and cookery science
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• v.12 no.3
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• pp.372-376
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• 1996

Antioxidative activities of the extracts from Schizandra Chinesis Baillon (Omija) with various solvent were compared with some commercial antioxidants. AS (antioxidative index; induction period of oil containing extract/induction period of control oil) of Omija extracts from five kinds of solvents (MeOH, EtOH, BtOH, EA, PE) and other antioxidants were shown as following orders: 0.02% BHT > 0.05% EA > 0.01% MeOH > 0.05% EtOH > 0.1% EA > 0.05% PE > 0.05％ BuOH >> 0.02% alpha-tocopherol. Antioxidative effects of 0.05% EA and 0.05% MeOH extracts during autoxidation (60${\pm}$ 2$^{\circ}C$) were higher than those (If the other extracts but were not greater than that of 0.02% BHT. However, Al of EA and MeOH, EtOH extracts during thermal oxidation (180${\pm}$2$^{\circ}C$) were greater than that of BHT. The antioxidant effect of alpha-tocopherol showed no apparent difference or a prooxidant effect as compared with result of control.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.6
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• pp.844-850
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• 2013

In this study, the optimal extraction conditions for three medicinal herbs as functional sources against inflammatory and arthritic diseases were developed. Traditional medicinal herbs were screened for their inhibition of hyaluronidase (HAse) activity and nitric oxide (NO) synthesis. For the screening of anti-inflammatory properties, ethanolic extracts of 53 species of traditional medicinal herb were examined. We confirmed that Astragalus membranaceus (A.R.), Schisandra chinensis (S.F.), and Platycodon grandiflorum (P.G.) inhibit NO production. For extraction from all three herbs simultaneously, an ethanol concentration of 95%, a 1:2:1 mixture ratio, and at 50 rpm mixing speed, for over 12 h and at $30^{\circ}C$ was the best condition for optimal extract yield and NO inhibition effects. HAse inhibition from the three herb extraction was three fold higher than single samples. The ethanol extracts were fractionated with various solvents (n-hexane, chloroform, ethyl acetate, n-butanol, and water). The ethyl acetate-soluble fraction of the herb mixture showed the highest extract yield (13%) and NO inhibition effects (73%). In conclusion, this study provides experimental evidence that a mixture of P.G., A.R., and S.F. could be used as a source of antioxidant ingredients in the food industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6000-6007
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• 2013

Cr(VI)-heterocyclic complex[Cr(VI)-isoquinoline] was synthesized by the reaction between of heterocyclic compound(isoquinoline) and chromium trioxide, and characterized by IR and ICP analysis. The oxidation of benzyl alcohol using Cr(VI)-isoquinoline in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order : cyclohexene$CH_3$, m-Br, m-$NO_2$). Electron- donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.69(308K). The observed experimental data have been ratiolized. The hydride ion transfer causes the prior formation of a chromate ester in the rate-determining step.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.293-299
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• 2020

This study was undertaken to optimize combining the processes of enzymatic hydrolysis and extraction for lycopene production from autumn olive berry. The autumn olive berry was pulverized and suspended in water, followed by treatment with various hydrolytic enzymes including Ceremix, Celluclast, AMG, Viscozyme, Pectinex, Promozyme, Ultraflo and Tunicase. Reaction solutions were subjected to extraction by applying different organic solvents including acetone, ethyl acetate, hexane and chloroform. Highest yields of lycopene extraction were obtained with the Ceremix (hydrolysis enzyme) and chloroform (extraction solvent) combination. Subsequently, using this ideal combination, enzymatic hydrolysis conditions, including enzyme concentration, pH and temperature, were statistically optimized to 0.58%, 5.5 and 54.4℃, respectively, by applying the response surface method. The lycopene extraction yield increased 2.3-fold (22.6 mg/100g) by using the selected combined process. We propose that these results could be used for the future development of bioactive materials required for bio-health care products.