• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2443-2447
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• 2014

A kinetic study is reported on nucleophilic substitution reactions of 4-nitrophenyl nicotinate (7) and 4-nitrophenyl isonicotinate (8) with a series of cyclic secondary amines in $H_2O$ containing 20 mol % DMSO at $25.0^{\circ}C$. The Br${\o}$nsted-type plots for the reactions of 7 and 8 are linear with ${\beta}_{nuc}=0.90$ and 0.92, respectively, indicating that the reactions proceed through a stepwise mechanism with expulsion of the leaving group occurring in the rate-determining step. Comparison of the reactivity of 7 and 8 with that of 4-nitrophenyl benzoate (2a) and 4-nitrophenyl picolinate (6) has revealed that their reactivity toward the amines increases in the order 2a < 7 < 8 < 6, although the reactions of these substrates proceed through the same mechanism. Factors that control reactivity and reaction mechanism have been discussed in detail (e.g., inductive and field effects, H-bonding interaction, solvent effect, etc.).

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.4 no.2
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• pp.121-123
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• 2018

Fluoride is one of most important atoms for both clinical and pharmaceutical usage. Associated with such a strong need, $^{18}F$-fluoride has been widely used as an essential radioisotope. The fluoride always suffers from strong solvation effects through strong hydrogen bonding, which reduce the reactivity of fluoride anion. To enhance the reactivity, the concept of naked fluoride was introduced in the fluorination field. In this essay, I will briefly describe the history of naked fluoride concept and development of naked fluoride sources.

• The Journal of the Acoustical Society of Korea
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• v.21 no.8
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• pp.708-718
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• 2002

In this paper, the problems in identifying the noise sources by using the sound intensity technique are dealt with for the general radiated near-field from vibro-acoustic sources. For this purpose, a three-dimensional model structure resembling the engine room of a car or heavy equipment is considered. Similar to the practical situations, the model contains many mutually coherent and incoherent noise sources distributed on the complicated surfaces. The sources are located on the narrow, connected, reflecting planes constructed with rigid boxes, of which a small clearance exists between the whole box structure and the reflecting bottom. The acoustic boundary element method is employed to calculate the acoustic intensity at the near-field surfaces and interior spaces. The effects of relative source phases, frequencies, and locations are investigated, from which the results are illustrated by the contour map, vector plot, and energy streamlines. It is clearly observed that the application of sound intensity technique to the reactive or reverberant field, e.g., scanning over the upper engine room as is usually practiced, can yield the detection of fake sources. For the precise result for such a field, the field reactivity should be checked a priori and the proper effort should be directed to reduce or improve the reactivity of sound field.

• Korean journal of applied entomology
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• v.57 no.1
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• pp.7-13
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• 2018

Currently, there is no available tool that rapidly diagnoses pine wood nematode (PWN)-infected pine trees in the field. In this study, we synthesized and purified PWN Galectin, which might be an antigen specific to PWN, using the Baculovirus expression system. We used PWN Galectin as an antigen for generating 1,464 fusion hybridoma cell lines secreting monoclonal antibodies (Mabs). Among them, we selected 62 fusion hybridoma cell lines showing high reactivity to PWN Galectin. We further selected 12 fusion hybridoma cell lines showing high reactivity to the standard PWN-infected pine tree phosphate buffered saline (PBS) extract. Additionally, two fusion hybridoma cell lines showing no or extremely low reactivity were used as controls. The selected fusion hybridoma cell lines were subjected to limiting dilutions for selecting and establishing Mab-secreting cell lines showing higher reactivity to the standard PWN-infected pine tree extract than to the standard normal pine tree PBS extract. Moreover, the selected fusion hybridoma cell lines were further selected based on their higher reactivity to PWN protein extracts than to three non-pathogenic nematode protein extracts. The Mab-secreting cell lines established in this study could be used to develop rapid diagnostic tools that can be used in the field or in laboratories for detecting PWN-infected pine trees or PWN.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1077-1080
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• 2003

High reactivity metakaolin (HRM) is a manufactured pozzolan produced by thermal processing of purified kaolinitic clay. Field performance and laboratory research of concrete containing HRM have demonstrated its value for bridge decks, bridge deck overlays, high-strength concrete and masonry products. This paper discusses laboratory evaluations to assess the physical properties of antiwashout underwater concrete (AWC) containing HRM, such as pH value, suspended solids, slump flow, and compressive strength. There were not much variations of pH value with the changing HRM contents, but suspended solid test showed that the amount of suspended solids of AWC with 10 and 20% of HRM were reduced in comparison with plain. Due to the fast hydration and reaction property of HRM, slump flow was decreased with increasing HRM contents. According to the results of compressive strength test, AWC with 10 and 20% of HRM showed higher strength characteristic than plain at all curing ages.

• Bulletin of the Korean Chemical Society
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• v.1 no.3
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• pp.98-101
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• 1980

For the first time we have synthesized thiabenzene radical by the reaction of thiopyrylium cation with alkali metals. As might be expected for a free radical, ESR-spectrum of 2,4,6-triphenylthiabenzene radical shows the single signal with g-value of 2.0045. The proton signal of 2,4,6-triphenylthiabenzene radical in nmr spectrum shifts to the higher field than that of 2,4,6-triphenylthiopyrylium cation by ca. 0.5 ppm. From the UV-spectrum of thiabenzene radical the presence of 6${\pi}$ non-benzenoid aromatic system was observed as in the case of thiopyrylium cation. The reactivity of alkali metals with thiopyrylium cation increases in the order of decreasing ionization energy, Li

• Journal of Korean Academy of Addiction Psychiatry
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• v.18 no.1
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• pp.17-22
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• 2014

Virtual reality (VR) provides an immersive and interactive 3-dimensional system, which allows an individual to become immersed in a computer-generated situation. VR technology has been administered in the exposure-based treatment of a variety of psychiatric disorders, including acrophobia, fear of flight, and post-traumatic stress disorder. Furthermore, VR systems have also been developed for the use of research and treatment in addiction. They might have advantages in cue exposure therapy, by increasing the salience of cues, as well as assessments of cue reactivity in addiction. This article summarizes the application of VR in the field of psychiatry. More importantly, it suggests the possibilities of clinical use of VR technology, in the treatment of addiction.

• Journal of Hydrogen and New Energy
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• v.22 no.1
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• pp.92-99
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• 2011

Barium cerate ($BaCeO_3$) related perovskite ceramics currently dominate the high-temperature proton conductor field. Unfortunately, these materials have very stringent environmental limitations necessitating the costly and complex conditioning or cleaning of the application feed-gas. Commercial realization has been hampered, in part, because of the reactivity of $BaCeO_3$ with $CO_2$, and to some extent $H_2O$. And sintered $BaCeO_3$ decomposed at a rate comparable to the powder samples. In this article, the chemical stability and the structural changes of $BaCe_{0.9-X}Y0.1La_XO_{3-\delta}$ (X=0, 0.1, 0.2) have been systematically investigated in the atmosphere containing carbon dioxide ($CO_2$) and water vapor ($H_2O$). The sintering characteristics were studied in $1600^{\circ}C$, sintered pellets disintegrate and decompose upon contacting boiling water on the surface only.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.7
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• pp.1062-1068
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• 2019

Objective: For many generations, most species of farm animals have been subjected to intense and strictly targeted selection for improvement of their performance traits. This has led to substantial changes in animal anatomy and physiology, which resulted in considerable differences between the current animal breeds and their wild ancestors. The aim of the study was to determine whether there is breed-specific variability in behaviour as well as differences in emotional reactivity and preferences of laying hens. Methods: The investigations involved 50 Green-legged Partridge, 50 Polbar, and 50 Leghorn hens. All birds were kept in the same conditions, and the behavioural tests were carried out at 30 weeks of age. We used the tonic immobility test and a modified open-field test including such objects as water, commercial feed, feed enriched with cereal grains, finely cut straw, and insect larvae, a sandpit, a mirror, and a shelter imitating a hen nest. Results: The research results demonstrate that the birds of the analysed breeds differ not only in the excitability and emotional reactivity but, importantly, also in the preferences for environment-enriching elements. Ensuring hens' well-being should therefore be based on environmental modifications that will facilitate acquisition of essential elements of chickens' behaviour. The greatest emotional reactivity was found in the Leghorn breed, which may be a result of correlated selection aimed at an increase in chicken productivity. Conclusion: The differences in the behaviour of the birds from the analysed breeds indicate that laying hens cannot be regarded as one group of animals with the same environmental requirements.

• Journal of environmental and Sanitary engineering
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• v.14 no.1
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• pp.54-61
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• 1999

The industrial techniques of ultrasound have been used in the various fields, such as cleaning, medical surgery, emulsification, cell disruption etc. Especially the application of cell disruption was interested in the field of disinfection process in water by ultrasonic irradiation. It has been recognized that the ultrasounds are irradiated in aqueous solution, cavitation bubbles are generated and shock waves of high temperature and pressure are emitted as the bubbles are developed and finally broken, which function as a energy source to promote reaction efficiencies of various kinds of chemical reactions such as disinfection reaction in water. Therefore, this study was performed to apply the ultrasound for the disinfection method of infected drinking raw water and to discuss the limiting factors such as pH, sample volume and reaction temperature influenced on the removal efficiency of E. coli from experimental analysis of the results obtained in bench-scale plant. For the experiments to measure the influence of reaction parameters in the ultrasonic disinfection process, escalated reactivity of aqueous solutions was excellent when pH in aqueous solution was low, and sample volume was small. On the contrary, the reactivity of disinfection became elevated when reaction temperature was high. It was found that the rate constant of disinfection reaction was applied by Chick's law, reaction kinetics of Chick's law was irreversible and pseudo-first order at all the tested conditions.As a conclusion it appeared that the technology using ultrasonic irradiation can be applied to the treatment of disinfection in infected water which are difficult to be treated by conventional methods.