• Bulletin of the Korean Chemical Society
• /
• 제10권3호
• /
• pp.258-261
• /
• 1989

The electrochemical behaviors of 4-(2)-thiazolylazo)-resorcinol (TAR) in acetonitrile solution was studied by DC polarography, cyclic voltammetry, controlled-potential coulometry and UV-Vis spectroscopy. The electrochemical reduction of TAR occurs in four-one electron reduction steps in acetonitrile solution. The products of the first and the third electron transfer are speculated to be a relatively stable anion radical. The second electron transfer to the dianion is followed by a chemical reaction producing a protonated species. The product of the fourth electron transfer also produces the corresponding amine compounds with a following reaction. Also every reduction wave was diffusion controlled. The first reduction wave is considerably reversible and the other waves are less reversible.

• Journal of Electrochemical Science and Technology
• /
• 제12권2호
• /
• pp.167-172
• /
• 2021

he progressively improved sensing sensitivity (∆λ_SPR/∆n, nm/RIU) to detect the refractive index is observed on the SPR platform of an Au-covered epoxy gratings in an increase in potential cycling in a typical three-electrode cell. Here, a DVD-R optical disc was used as a structure template to prepare an Au-covered epoxy gratings, and the newly formed reverse track pitch structure on the epoxy substrate was used as a working electrode directly in aqueous sulfuric acid solution. It is expected that Au reconstruction by potential cycling in sulfuric acid electrolyte increases the packing density of Au atoms in the grain boundary and improves the propagation of electromagnetic waves.

• 한국전기전자재료학회논문지
• /
• 제11권8호
• /
• pp.658-663
• /
• 1998

Ferrite plating enables were grown by ferrite by plating method in solution at low temperature(<10$0^{\circ}C$). This faciltates the fabrication of new ferrite thin film devices using non- heat-resistant materials(plastic, GaAs ect) as substrates. Combining the ferrite plating with sonochemistry, application of power ultrasonic waves to stimulate chemical reactions, the crystallinity and qualities of films were improved. Modifying the reactions cell and plating conditions further improved the film quality.

• 한국재료학회지
• /
• 제19권3호
• /
• pp.169-173
• /
• 2009

In chemistry, the study of sonochemistry is concerned with understanding the effect of sonic waves and wave properties on chemical systems. In the area of chemical kinetics, it has been observed that ultrasound can greatly enhance chemical reactivity in a number of systems by as much as a million-fold. Nano-technology is a super microscopic technology in which structures of 100 nanometers or smaller can be investigated. This technology has been used to develop $TiO_2$ materials and $TiO_2$ devices of that size. Thus far, electrochemistry methods and photochemistry methods have generally been used to create $TiO_2$ nano-size particles. However, these methods are complicated and create pollutants as a by-product. In the present study, nano-scale silver particles (5 nm) were prepared in a sonochemistry method. Sonochemistry deals with mechanical energy that is provided by the collapse of cavitation bubbles that form in solutions during exposure to ultrasound. $TiO_2$ powders 25 nm in size doped with Ag were formed using an ultrasonic sound technique. The experimental results showed the high possibility of removing pollution through the action of a photocatalyst. This powder synthesis technique can be considered as an environmentally friendly powder-forming processing owing to its energy saving characteristics.

• 대한화학회지
• /
• 제32권3호
• /
• pp.195-202
• /
• 1988

Acetonitrile 용액중에서 3-phenyl-4-nitrosydnone의 전기화학전 환원을 direct current, differential pulse polarography, cyclic voltammetry 그리고 controlled potential coulometry 방법으로 연구하였다. Phenyl-N 단일 결합의 분리 이전에 nitro 기능기의 비가역적 전자 전달-화학반응(EC)기구의 진행으로 다전자 이동에 의한 amino(또한 hydroxylamino)기를 형성하고, 높은 음 전위 영역에서 2,3 비가역성 환원파의 일전자전달-화학반응에 의한 phenyl hydrazine을 생성하였다. 음극 반파 전위들은 cetyltrimethyl ammonium bromide의 억제 효과에 의해 음의 값으로 이동하였고 한편, sodium lauryl sulfate micelle은 높은 음전위 영역에서 제 2,3 환원파의 가역성산화 peaks를 보였다.

• 천문학논총
• /
• 제27권4호
• /
• pp.225-230
• /
• 2012

Supernovae (SN) and supernova remnants (SNRs) play a major role in the life-cycle of interstellar dusts. Fast shock waves generated by SN explosions sweep out the interstellar space destroying dust grains and modifying their physical and chemical properties. The dense, cooling SN ejecta, on the other hand, provide an environment for dusts to condense. Recent space-infrared telescopes have revealed the hidden universe related to these fascinating microscopic processes. In this paper, I introduce the results on stardusts in young core-collapse supernova remnants obtained by AKARI. The AKARI results show diverse infrared characteristics of stardusts associated with SNRs, implying diverse physical/chemical stellar structures and circumstellar environments at the time of explosion.

• Bulletin of the Korean Chemical Society
• /
• 제26권11호
• /
• pp.1717-1722
• /
• 2005

The analytical transfer matrix method suggests a new quantization condition for calculating bound state eigenenergies exactly. In the quantization condition, the phase shifts of bound state wave functions scattered at classical turning points are explicitly introduced. We calculate the phase shifts of eigenfunctions of the Morse potential with various boundary conditions in order to understand the physical meaning of phase shifts. The Morse potential is known to adequately describe the interaction energy between two atoms and, therefore, it is frequently used to determine the vibrational energy levels of diatomic molecules. The variation of Morse potential eigenenergies influenced upon by changing boundary conditions is also investigated.

• Bulletin of the Korean Chemical Society
• /
• 제25권2호
• /
• pp.293-297
• /
• 2004

The ignition of monomethylamine was studied in reflected shock waves over the temperature range of 1255- 1579 K and the pressure range of 1.04-1.51 bar. The ignition delay time was measured by the sudden increase of pressure profile and the radiation emitted by OH radicals. The relationship between the ignition delay time and the concentrations of monomethylamine and oxygen was determined in the form of mass-action expressions with an Arrhenius temperature dependence. In contrast to the behavior observed in hydrocarbons, monomethylamine acts to accelerate rather than inhibit its own ignition. And numerical modeling of the ignition of $CH_3NH_2$ has also been carried out to test the several kinetic mechanisms.

• 대한화학회지
• /
• 제7권1호
• /
• pp.34-37
• /
• 1963

Cobalt(Ⅲ) ion gives two step waves with $E_{1/2}$－0.1V(?)(vs.S.C.E.) and $E_{1/2}$－1.37V(vs. S.C.E.) from a base electrolyte consisting of 0.1 M TEA＋sodium borate＋0.0002% gelatin. The first wave results from the reduction Co(Ⅲ) to Co(Ⅱ). The second wave corresponding to the reduction Co(Ⅱ) to Co(0) and this wave is diffusion controlled. The diffusion current constant of the second wave is 2.7. Under these-conditions, diffusion current of the second wave is proportional to the concentration of Co (Ⅱ) in the range of $10^{-3}{\sim}10^{-4}$ M.

• 한국임상수의학회지
• /
• 제15권2호
• /
• pp.325-330
• /
• 1998

The purpose of this study is to investigate the effect of acupuncture after the induction of acute kidney disease in dogs by ethylene glycol. Twenty four mixed breed, adult cats were used in the experiment. Ethylene glycol was administered orally at 1 ml/kg in 24 cats, and then 6 cats were treated by acupunchuture 6 cats were treated by electroacupuncture, 6 cats were treated by acupuncture and 6 cats were not treated as a control group. Treatment was done once daily far 4 dsys. The acupoint used were Gan-shu and Tai-xi. The effect of acnpuncture was evaluated by clinical symptom, blood chemical values, electrocardiogram (ECG) and histopathologkal findings. After treatement, acupuncture group revealed relatively fast recovery compared with other groups, in clinical symptoms, blood chemical values, ECG waves and histopathological findings. Laserpuncture group revealed secondly fast recovery compared with control group.