• Archives of Pharmacal Research
• /
• 제15권4호
• /
• pp.309-316
• /
• 1992

The effects of lipid peroxidation on the fluidity of the lipid bilayers of the human erythrocyte ghosts and egg-lecithin phospholipid liposomes have been studied. For the measurements of the peroxidation extent and the fluidity of the membranes, the thiobarbituric acid-reactive substances and the fluorescence depolarization of 1, 6-diphynyl-1, 3, 5-hexatriene labelled into the membrane were employed, respectively. The lipid peroxidation was performed in hypoxanthine/xanthine oxidase/ferrous ion, and hydrogen peroxide/ferrous ion systems. The results of these experiments show that both of the xanthine oxidase and hydrogen peroxide systems effectively. The lipid peroxidation decreased the fluidity of the membranes, especially at the very early stage of the peroxidation reaction. The decrease in the fluidity of membrane by the lipid peroxidation has been ascribed to the alteration of the polyunsaturated acyl chains of lipids and cross linkages among the membrane components. However, under drastic condition of lipid peroxidation, tdhe fluidity of the membrane rather increased possibly due to the deterioration of the membrane integrity by the peroxidation. Morphological change of the erythrocyte on peroxidation has also been observed.

• 한국전기전자재료학회논문지
• /
• 제11권2호
• /
• pp.82-89
• /
• 1998

The experimental results using the X -ray technique, the position and structure of mica crystal are not observed the phase change of aging and sound specimen respectively. However, We could observe the intensity difference of crystal element in both atmospheres. The analysis of mica-epoxy materials by optical microscope are shown that the each surface of sound and aging specimens are different in both atmospheres Also, the experimental results have shown that the potassium ions of mica cristal are substituted by hydrogen ions at boundary area of mica-epoxy and/or mica-mica. On components made of mica, a potassium ion of big atomic radius, is replaced by hydrogen ion of small atomic radius. The voids are created by the difference of radius progressed by combined stresses. Through these phenomena, it has been proposed that the conductive layers made of potassium enable the voids to form and the cracks to create by high electric field.

• Journal of Welding and Joining
• /
• 제29권5호
• /
• pp.95-98
• /
• 2011

Recently, there is a growing tendency that fine-pitch electronic devices are increased due to higher density and very large scale integration. Finer pitch printed circuit board(PCB) is to be decrease insulation resistance between circuit patterns and electrical components, which will induce to electrical short in electronic circuit by electrochemical migration when it exposes to long term in high temperature and high humidity. In this research, the effect of soldering flux acting as an electrical carrier between conductors on electrochemical migration was investigated. The PCB pad was coated with OSP finish. Sn3.0Ag0.5Cu solder paste was printed on the PCB circuit and then the coupon was treated by reflow process. Thereby, specimen for ion migration test was fabricated. Electrochemical migration test was conducted under the condition of DC 48 V, $85^{\circ}C$, and 85 % relative humidity. Their life time could be increased about 22% by means of removal of flux. The fundamentals and mechanism of electrochemical migration was discussed depending on the existence of flux residues after reflow process.

• 한국환경과학회지
• /
• 제24권6호
• /
• pp.785-792
• /
• 2015

This study investigates weekday/weekend characteristics of $PM_{10}$ concentration and chemical composition of water-soluble ions in Busan in the spring of 2013. Contribution rate of water-soluble ions to PM10 concentration in weekday/weekend were 41.5% and 38.5%, respectively. Contribution rate of SO_4{^{2-}}$ to total ion mass in weekday/weekend were 30.4% and 33.8%, respectively. Contribution rate of total inorganic water-soluble ions in PM10 in weekday/weekend were 42.2% and 39.1% (mean 41.4%), respectively. $[NO_3{^-}/SO_4{^{2-}}]$ ratio in weekday/weekend were 1.01 and 0.97(mean 0.99), respectively, which indicated that weekday ratio was higher. Contribution rate of sea salts and $Cl^-/Na^+$ ratio in PM10 in weekday/weekend were 8.1% and 7.6%, 0.37% and 0.41%, respectively. This research will help understand chemical composition of water-soluble ions during the weekday/weekend and will be able to measure the contribution level of artificial anthropogenic source on urban air.

• Bulletin of the Korean Chemical Society
• /
• 제26권6호
• /
• pp.903-908
• /
• 2005

The sharp-line absorption and emission spectra of $(H_{13}O_6)${$trans-[Cr(Me_2tn)_2Br_2]$}$_2Br_2(ClO_4)\;(Me_2$tn = 2,2-dimethyl-1,3-diaminopropane) have been measured between 13000 $cm^{-1}$ and 16000 $cm^{-1}$ at 5 K. The 298 K infrared and visible absorption spectra have also been measured. The nine electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using observed transitions, a ligand field analysis has been performed to probe the ligand field properties of coordinated atoms in the title chromium(III) complex ion. The zero-phonon line in the sharp-line absorption spectrum splits into two components by 286 $cm^{-1}$, and the large $^2E_g$ splitting can be reproduced by the modern ligand field theory. It is confirmed that nitrogen atoms of the Me2tn ligand have a strong $\sigma$-donor character, but the bromide has weak $\sigma$- and $\pi$-donor properties toward chromium(III) ion.

• The Korean Journal of Physiology
• /
• 제11권2호
• /
• pp.67-71
• /
• 1977

This study was undertaken to investigate the effect of cingulate cortical ablation upon gastric secretion and its components in rats. 23 male rats were divided into the cingulate(N=9) and the operated control(N= 14) groups. Cingulate cortex was ablated through a slit-shaped opening(1 mm in width, 5 mm in length) which was made symmetrically on both sides of, and parallel to, the sagittal suture by removing a bone flap from frontal bone on each side. In the operated control group, the surgical procedure was ended by the removal of the bone flap. Under light ether anesthesia, experimental animals were placed in a restraining jacket of fine mesh wire and gastric juice was collected for 5 hours via a canula which had been inserted through the anterior abdominal wall into the antral portion of the lumen of the stomach. Volume of the gastric juice was measured, and total acid output and free acid output were titrated with 0.04 N NaOH solution by using phenolphthalein and Topfer's reagent at indicator, and chloride ion output was estimated by means of chloridometer. Results obtained were that volume, total acid output, free acid output and chloride ion output of the gastric juice were higher significantly in the cingulate group than in the operated control group. It is inferred from the above results that the cingulate cortex exerts a fascilitatory influence upon gastric secretion and acid output in rats.

• 한국전기전자재료학회논문지
• /
• 제32권3호
• /
• pp.179-186
• /
• 2019

This work investigated the effects of different conductive agents on the electrochemical properties of anodes. SiOx possesses high theoretical capacity and shows excellent cycle performance; however, the low initial coulombic efficiency and poor electrical conductivity limit its applications in real batteries. In this study, electrodes were fabricated using two different conductive agents, and the resulting physical and electrochemical properties were analyzed. SEM observations confirmed the formation of a CNT conductive network throughout the electrodes, while the electrical conductivity contributed to the electrode was confirmed by impedance measurements. Thus, the electrode fabricated with the CNT conductive agent showed greater capacity and superior cycle performance than did the electrode fabricated using the DB conductive agent.

• 한국표면공학회지
• /
• 제53권6호
• /
• pp.280-284
• /
• 2020

Electron beam irradiation is widely used as a type of surface modification technology to advance surface properties. In this study, the effect of electron beam irradiation on properties, such as surface hardness, wear resistance, roughness, and critical load of Titanium Aluminium nitride (TiAlN) films was investigated. TiAlN films were deposited on the SKD-61 substrate by using cathode arc ion plating. After deposition, the films were bombarded with intense electron beam for 10 minutes. The surface hardness was increased up to 4520 HV at electron irradiation energy of 1500 eV. In addition, surface root mean square (RMS) roughness of the films irradiated at 1500 eV shows the lowest roughness of 484 nm in this study.

• Journal of Electrochemical Science and Technology
• /
• 제14권3호
• /
• pp.272-282
• /
• 2023

Ni-rich layered oxides cathode has recently gained attention as an advanced cathode material due to their applicable energy density. However, as the Ni component in the layered site is increased, the high reactivity of Ni⁴⁺ results in parasitic reaction associated with decomposing electrolyte, which leads to a rapid decreasing the lifespan of the cell. The electrolyte additive triallyl borate (TAB) improves interfacial stability, leading to a stable cathode-electrolyte interphase (CEI) layer on the LNCM83 cathode. A multi-functionalized TAB additive can produce a uniformly distributed CEI layer via electrochemical oxidation, which implies an increase in long-term cycling performance. After 100 cycles at elevated temperature, the cell tested by 0.75 TAB retained 88.3% of its retention ratio, whereas the cell performed by TAB-free electrolyte retained 64.1% of its retention. Once the TAB additive formed CEI layers on the LNCM83 cathode, it inhibited the decomposition of carbonate-based solvents species in addition to the dissolution of transition metal components from the cathode. The addition of TAB to LNCM83 cathode material is believed to be a promising way to increase the electrochemical performance.

• 분석과학
• /
• 제17권5호
• /
• pp.369-374
• /
• 2004

플라스틱을 황산으로 탄화시키고 질산으로 산화 분해한 후 과잉의 황산과 질산을 증발 건조에 의해 제거한다. 이때 침전된 납화합물 ($PbSO_4$)의 $SO{_4}^{-2}$ 이온을 염산산성에서 HI에 의해 $H_2S$로 환원하여 휘발시킨 다음 납을 용해한후 AAS와 ICP로 측정하였다. PVC-Pb 표준시료 (690~34610mg/kg)를 이용하여 재현성 실험을 하였으며 예상농도에 대비하여 99.9% 이상의 정확성을 보였다. 정밀성은 AAS는 99.8%, ICP는 99.9%로 비슷하였다.