• Journal of the Korean Chemical Society
• /
• v.37 no.1
• /
• pp.68-75
• /
• 1993

Various biological activities (enzyme inhibitory potency, lipoxygenase inhibition, tadpole narcosis, vapor toxicity and heat of vaporization) of molecules are correlated with molecular descriptors. The molecular descriptors used in this works are molecular connectivity index, Wiener distance index and ad hoc descriptor, which can encode information about branching, size, cyclization, unsaturation, hetero atom content and polarizability. It is found that calculated values from multiple regression equations are in a good agreement with experimental data on five biological activities of alcohol, ester and ketone compounds.

• Journal of applied mathematics & informatics
• /
• v.40 no.5_6
• /
• pp.959-977
• /
• 2022

The topological indices are numerical parameters which determined the biological, physical and chemical properties based on the structure of the chemical compounds. One of the recently topological indices is the uphill Zagreb indices. In this paper, the formulae of some uphill Zagreb indices for a few graph operations of some graphs have been derived. Furthermore, the precise formulae of those indices for the honeycomb network have been found along with their graphical profiles.

• Journal of Environmental Health Sciences
• /
• v.46 no.5
• /
• pp.588-598
• /
• 2020

Objectives: Human indices were developed to determine returning point of residents and damage restoration after the chemical accident Methods: To determine the returning point of residents after the chemical accident, a new concept, the standard man model was introduced as a human index, in which both H-code and its acute effects were main idea. To evaluate the applicability, a hydrogen fluoride leakage accident in Gumi was applied. The returning point were suggested as the conservative remission period of acute effects among relevant hazard effects and compared with actual returning point. The coverage of each age group were considered with reflecting average daily dose expected for actual residents. In addition, a relief-index as a social-scientific approach was reflected as well to apply the damage restoration Results: Actual returning point of residents in Gumi was 88 days; and that of standard man model suggested was 84 days. The expected amount of exposure at aged 12 or under was at least 2.35 times greater than that of this model, 40s, theoretically. However, their population ratio was less than 1%, so 99% of residents could be applied when the standard man model was applied. The relief-index was as an objective and quantitative methodology to apply the qualitative aspect. Conclusions: Although evaluated as a relatively positive result, there was a limitation such as the number of accident applied to the verification of standard man model. The relief index was also considered, but further research should be carried out to find threshold level for the relief.

• Korean Chemical Engineering Research
• /
• v.54 no.3
• /
• pp.332-339
• /
• 2016

We evaluate the technical competitiveness of Korea in lubricating oil industries by comparatively analyzing the patent activities. In achieving the goal, we collect and statistically analyze the historical patent data of lubricants production technologies. We here consider nine technology groups classified by their raw material types and process features of four countries such as USA, Japan, EU and Korea. We then evaluate Korea's competitiveness in lubricating oil industries using different patent index including patent family size, cites per patent, patent impact index and technology strength. Based on the evaluation results, we finally propose the practical strategies to improve Korea's competitiveness in lubricants industries.

• Korean Chemical Engineering Research
• /
• v.53 no.6
• /
• pp.762-769
• /
• 2015

The titania ($TiO_2$) nanoparticles with a diameter 2?3 nm were synthesized by controlling hydrolysis of titanium tetraisopropoxide (TTIP) in acid solution. Organic-inorganic hybrid coating solutions were prepared by reacting the titania nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at $120^{\circ}C$ after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films showed high optical transparency of 90% in the visible range and exhibited a pencil hardness of 2H. Also, the refractive index at 633 nm wavelength of coating films enhanced from 1.502 to 1.584 as the weight content of titania nanoparticles in the coating solutions increased from 4% to 25%.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.10a
• /
• pp.158-162
• /
• 2001

The effects of chemical treatment on Kevlar-29 fibers have been studied in a composite system. The surface characteristics of the Kevlar-29 fibers were characterized by pH, acid-base value and X-ray photoelectron spectroscopy (XPS). The mechanical interfacial properties of final composites were studied by interlaminar shear strength (ILSS) and critical stress intensity factor ($K_{IC}$). Also, the impact properties of the composites were investigated in the differentiating studies between initiation and propagation energies, and ductile index (DI) along with maximum farce and total energy. It was found that the chemical treatment with phosphoric acid ($H_3PO_4$) solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improving the mechanical interfacial strength of the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force in a composite system.

• Journal of the Korean Chemical Society
• /
• v.31 no.2
• /
• pp.143-152
• /
• 1987

$\pi$-Binding energy of the 153 kinds of unsaturated acyclic polyenes and unsaturated cyclic polyenes has been calculated by the Kier's Molecular Connectivity Index. An excellent linear correlation is found between HMO $\pi$-binding energy and $\pi$-binding energy calculated by the Kier's Molecular Connectivity Index. In either class of unsaturated acyclic hydrocarbons and unsaturated cyclic hydrocarbon, the regression analysis reveals a highly significant linear correlation between $E_{\pi}$ and $^1{\chi}^v$ (the first order valence connectivity index).

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.141-141
• /
• 2013

Shape control of metal nanocrystals has broad applications, including catalysis, plasmonics, and sensing. It was found that controlling the atomic arrangement on metal nanocrystal surfaces affects many properties, including the electronic dipole or work function. Tuning the surface structure of exposed facets of metal nanocrystals was enabled by shape control. We investigated the effect of shape on nanomechanical properties, including friction and adhesion forces. Two nanoparticles systems, high-index {321} and low-index {100}, were used as model nanoparticle surfaces. Scanning force microscopy was used to probe nanoscale friction and adhesion. Because of the abundant presence of high-density atomic steps and kinks, high-index faceted nanoparticles have a higher surface energy than low-index faceted cubic nanoparticles. Due to this high surface energy, high-index faceted particles have shown stronger adhesion and higher friction than low-index nanoparticles. We discuss the results in light of the differences in surface energy as well as the effect of capping layers in the measurement.

• International Commerce and Information Review
• /
• v.16 no.4
• /
• pp.439-455
• /
• 2014

Korea-Japan trade has been trade deficit for a long time and therefore this matter must be a settled urgently for continuous economic growth of Korea. For reasons mentioned above, this study pays attention to Japan materials industry which has induced trade deficit in the Korea-Japan trade and this study analyzed competitiveness of Japan materials industry in the Korea market. This study special regard will be paid to the Compound and Chemical Products in Japan materials industry. For attaining the purpose of study, we collected related statistical data and Market Share Index, Trade Specialization Index and Market Comparative Advantage Index used in study methodology From this analysis, we found that most of Japan material products have competitiveness in Korea market and chemical products used in photography & photo sensitized materials, paint & printing ink products particularly have very strong competitiveness in Korea Market.

• Journal of the Korean Society of Safety
• /
• v.28 no.1
• /
• pp.40-46
• /
• 2013

In the chemical process industries, accidents have a high potential and large effects on catastrophic results. Therefore the safety management for accident prevention plays a crucial role to guarantee the process safety. For these reasons, many systematic methods for safety management system have been widely employed in the fields of chemical processes. PSM (Process safety management) is one of most representative methods. The audit system, which is one of PSM system components, evaluates the performance of PMS system. However, most existing safety audit systems are not systematic and these are performed based on knowledges and experiences of various specialist. Moreover, the safety audit is only performed based on each independent technical component. So, the results of safety audit are not a quantitative index but only a series of commentaries. Finally, it is very difficult to obtain the comparison with other plants or industries. In this study, the novel systematic method and index-based accident database of auditing safety management systems for quantitative assessment are proposed. First, the elements of safety audit replace technical methods to categories of accident database. The F-N curve of each category for accident database is employed to derive the index for quantitative assessment. The Accidental Factor Risk Index (AFRI) is suggested for evaluating the effect of each element in accident database and safety audit system. The safety audit can be modified according to the proposed index.