• Analytical Science and Technology
• /
• v.6 no.3
• /
• pp.289-296
• /
• 1993

The formation of Mo(VI)-alizarin red S chelate ion and its extraction into an organic solvent by ion-pairing were studied for the separative determination of trace Mo(VI) in natural water samples. Natural water 100mL was sampled in 250mL separatory funnel. After Mo(VI)-ARS chelate ion was formed by adding 0.01M alizarin red S solution 0.5mL to the water sample of pH 4.0, 0.2% aliquat-336 chloroform solution 10mL was added and the solution was vigorously shaked for about 30 seconds to from the ion-pair between Mo(VI)-ARS and aliquat-336, completely. The solution was stood for about 90 minutes. And the organic phase was taken for the absorbance measurement of the ion-pair at 520 nm. The content of Mo(VI) in sample was obtained from the standard calibration curve. Several extraction conditions such as pH, adding amounts of alizarin red S and aliquat-336, and shaking and standing times were optimized. This procedure was applied to the analysis of river and tap waters. It could be confirmed from the recoveries of over 99% in samples spiked with a given amount of Mo(VI) that this method was quantitiative in the determination of trace Mo(VI) in a natural water.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.04a
• /
• pp.41-41
• /
• 2008

In general, polyimides (PIs) are used in alignment layers in liquid crystal displays (LCDs). The rubbing alignment technique has been widely used to align the LC molecules on the PI layer. Although this method is suitable for mass production of LCDs because of its simple process and high productivity, it has certain limitations. A rubbed PI surface includes debris left by the cloth, and the generation of electrostatic charges during the rubbing induces local defects, streaks, and a grating-like wavy surface due to nonuniform microgrooves that degrade the display resolution of computer displays and digital television. Additional washing and drying to remove the debris, and overwriting for multi-domain formation to improve the electro-optical characteristics such as the wide viewing angle, reduce the cost-effectiveness of the process. Therefore, an alternative to non-rubbing techniques without changing the LC alignment layer (i.e, PI) is proposed. The surface of LC alignment layers as a function of the ion beam (IE) energy was modified. Various pretilt angles were created on the IB-irradiated PI surfaces. After IB irradiation, the Ar ions did not change the morphology of the PI surface, indicating that the pretilt angle was not due to microgrooves. To verify the compositional behavior for the LC alignment, the chemical bonding states of the ill-irradiated PI surfaces were analyzed in detail by XPS. The chemical structure analysis showed that ability of LCs to align was due to the preferential orientation of the carbon network, which was caused by the breaking of C=O double bonds in the imide ring, parallel to the incident 18 direction. The potential of non-rubbing technology for fabricating display devices was further conformed by achieving the superior electro-optical characteristics, compared to rubbed PI.

• Journal of the Korean Vacuum Society
• /
• v.18 no.6
• /
• pp.440-446
• /
• 2009

Indium tin oxide(ITO) substrate is one of the key components of the touch panel and its sputtering process is dependent on the characteristics of various touch panel, such as driving type, size of panel, and the intended use. In this study, we optimized the sputtering condition of ITO film on polycarbonate(PC) by using in-line sputtering method for the application to resistive type touch panel. We varied the $O_2$/Ar gas ratio, sputtering power, pressure and moving speed of substrate to deposit ITO films at room temperature with the base vacuum of $1{\times}10^{-6}\;torr$. The sheet resistance and its uniformity, the transmittance, the thickness of the ITO film on PC substrate are investigated and analyzed. The optimized process parameters are as follows : the sheet resistance is $500{\pm}50\;{\Omega}$/□, the uniformity of sheet resistance is lower than 10%, the transmittance is higher than 87 % at 550nm, and the thickness is about 120~250. The optimized deposition conditions by in-line sputtering method can be applied to the actual mass production for the ITO film manufacturing technology.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.10 no.1
• /
• pp.109-119
• /
• 2002

This study is to estimate that food waste bags with biodegradable plastic are really decomposed by microorganism in composting with food waste and to examinate how biodegradable plastic affects composting. 6 kinds of 30%, 4 kinds of 100% and 2 kinds of none biodegradable plastics were used in d1is study. In 30% biodegradable plastics the highest Degradation rare is 6% in meso-condition and 10% in thermal-condition. Srain at auto break decreased to 150% in meso-condition and 120% in thermal-condition. Stress at max load were also reduced to $180kgf/cm^2$ in mesocondition and $200kgf/cm^2$ in thermal-condition. Usually, LLDPE decreased larger than HDPE in physical characreristics but HDPE is higher in degradation rate. 1n stain at auto break and stress ar max load 100% biodegradable plastic declined to 230% and to $380kgf/cm^2$ in meso-condition and to 440% and to $400/cm^2$ in thermal-condition respectively. 100% biodegradable plastics showed higher biodegradation and decomposition then 30%. They appeared clearly through SEM observation. As a result, it was not appropriate to use 30% biodegradable plastics as food waste bag because they were not decomposed perfectly. It is possible to use 100% biodegradable plastic as it but cost is too high. So development of technique is needed.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.6
• /
• pp.61-69
• /
• 2000

Indium-Tin Oxide (ITO) films were prepared on the commercial glass substrate by the Magnetron Sputtering method. The target was a 90wt.% $In_2O_3$-10wt.% $SnO_2$with 99.99% purity. The ITO films deposited by changing the partial pressure of oxygen gas ($O_2$/(Ar+$O_2$)) of 2, 3 and 5% as well as by changing the substrate temperature of $300^{\circ}C$ or $500^{\circ}C$. The influence of substrate pre-annealing and pre-cleaning on the quality of ITO film were examined, in which the substrate temperature was $500^{\circ}C$ and oxygen partial pressure was 3%. The characteristics of films were examined by the 4-point probe, Hall effect measurement system, SEM, AFM, Spectrophotometer, and X-ray diffraction. The optimum ITO films have been obtained when the substrate temperature is $500^{\circ}C$ and oxygen partial pressure is 3%. At optimum condition, the film showed transmittance of 81%, sheet resistivity of $226\Omegatextrm{cm}^2$, resistivity($\rho$) of $5.4\times10^{-3}\Omega$cm, carrier concentration of $1.0\times10^{19}cm^{-3}$, and carrier mobility of $150textrm{cm}^2$Vsec. From XRD spectrum, c(222) plane was dominant in the case of substrate temperature at $300^{\circ}C$, without regarding to oxygen partial pressure. However, in the case of substrate temperature at $500^{\circ}C$, c(400) plane was grown together with c(222) plane, only for oxygen partial pressure of 2 and 3%. In both case of chemical and ultrasonic cleaning without pre-annealing the substrate, it showed much almost same sheet resistivity, resistivity($\rho$), transmittance, carrier concentration, and carrier mobility. In case of $500^{\circ}C$/60min pre-annealing before ITO film deposited, both transimittance and carrier mobility are better than no pre-annealing, because pre-annealing is supposed to remove alkari ions diffusion from substrate. ITO film deposited on the Corning 0080 sybstrate showed a little bit better sheet resistivity, resistivity($\rho$), transimittance, carrier concentration than the film deposited on commercial glass. But no differences between Corning substrate and pre-annealed commercial glass substrate are found.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.9
• /
• pp.1308-1313
• /
• 2005

The physiological activity of Lycii fructus extracts were examined. Total phenolic contents in the ethanol extracts (9.5 mg/g) of Lycii fructus were higher than that of water extracts (8.7 mg/g). The chlorogenic acid ($1.7{\mu}g$ in water extracts and $1.3{\mu}g$ in $60\%$ ethanol extract) was the most abundant phenolic compound as analyzed by HPLC. The ABTS [2,2'-azinobis (3-othylbenfothiaznoline-6- sulfornic acid)] radical decolor-ization electron donating ability (DPPH) and antioxidant protection factor (PF) were determined for extracts from Lycii fructus. Water extract ($76.7\%$ on ABTS, $92.6\%$ on DPPH and 1.1 on PF) showed higher inhibition rate than $60\%$ ethanol extracts ($52.8\%,\;88.8\%$ and 1.0). Thiobarbituric acid reactive substance (TBARS) was determined as $1.5{\times}10^{-3}\;{\mu}M$ in $60\%$ ethanol extract. Ethanol extracts was more effective in decreasing TBARS than water extracts. The water extracts from Lycii fructus had higher angiotensin converting enzyme (ACE) inhibition activity than ethanol extracts. The result will be useful for functional foods application and under-standing the physiological activities of Lycii fructus.

• Korean Journal of Pharmacognosy
• /
• v.46 no.1
• /
• pp.78-83
• /
• 2015

This study was conducted to verify the potential of Allium hookeri to control glucose metabolism in a diabetes model. We fed the experimental diets (AL, AR, Dex) supplemented with the powder of leaf, root, or dextrin as a positive control, respectively at 3% of diet to the diabetic mice (C57BLKS/J, db/db) for 8 weeks. Control mice were fed with the diet supplemented with cornstarch (Cont) at 3% level of diet. At 8th week of feeding the diets, we measured body weight, blood glucose, HbA1c, and plasma insulin levels and conducted an oral glucose tolerance test (OGTT) and staining insulin immunoreactive cells in islets of pancreas. AL group treated with the leaf of A. hookeri showed significantly lower blood glucose and HbA1c levels, higher plasma insulin levels, and increased density of insulin immunoreactive cells compared with the Cont group. During the OGTT, AL group showed lower blood glucose levels than the Cont group for 120 min. Based on these results, leaf of A. hookeri is considered to be effective in improving glucose tolerance by partially affecting insulin secretion and it may be used to prevent and treat diabetic disease.

• Analytical Science and Technology
• /
• v.11 no.3
• /
• pp.189-193
• /
• 1998

Binary alloys, $MoRu_3$ and $MoRh_3$, have been prepared using arc melting furnace. Mo and the noble metals Ru and Rh are the constituents of metallic insoluble residues, which were found in the early days of the post-irradiation studies on uranium oxide fuels. Detailed structural informations about these alloys have not been reported on JCPDS files of ICDD (International Centre for Diffraction Data). The results of X-ray diffraction study showed that the alloy was crystallized in hexagonal close-packing, well known as ${\varepsilon}$-phase. The X-ray diffraction patterns of these alloys matched well to that of $WRh_3$ with $P6_3/mmc$ of space group. The lattice parameters, a and c, were calculated using the least squares extrapolation. It was found from X-ray photoelectron spectroscopic measurements that Mo on the surface of the alloy was oxidized to Mo(6+), which could be removed by sputtering with Ar ions for approximately 15 minutes. The changes in binding energy of Mo, Ru, and Rh on the surface of the alloy were not observed. Magnetic susceptibility measurements resulted in the typical Pauli-paramagnetic behavior in the temperature range of 2 to 300 K.

• Analytical Science and Technology
• /
• v.25 no.5
• /
• pp.273-283
• /
• 2012

Phthalate plasticizers are regulated by RoHS, REACH and CPSC as hazardous substances. Responding to these international environmental restrictions, we developed ABS certified reference material (CRM) for determination of phthalate plasticizers such as DMP, DEP, DBP, BBP, DEHP and DnOP. The candidate material has been made with ABS resin widely used in electric and electronic products and 6 kinds of phthalate plasticizers. The making of the material involved a series of processes like extruding, cooling, pelletizing, and drying using twin screw extruder. Then it has been certified according to ISO Guide 35. Using isotope dilution-gas chromatography/mass spectrometry (ID-GC/MS), homogeneity, short-term stability, and long-term stability were evaluated. The certified values were determined by using primary reference material (PRM) of KRISS for traceability. From now on, we will provide ABS CRM to national and international companies and research institutes after certification as certified reference material and registering on COMAR (code of reference material).

• Analytical Science and Technology
• /
• v.25 no.5
• /
• pp.265-272
• /
• 2012

Okamoto cavity was modified to generate high power (2.45 GHz, 2 kW) He, N2 and Ar plasmas with WR-340 waveguide. Many factors which influence to the plasma generation were optimized and investigated for the spectroscopic properties of the He plasma generated. Some of the important factors are the diameter of the inner conductor, the distance between the inner and outer conductors and the distance between the tip of the inner conductor and the torch. After optimization for the He, two torches (a commercial mini torch for ICP and a tangential flow torch made locally) were compared and showed similar results for the helium plasma gas flow of 25 L/min~30 L/min. A tall torch (extended) was used to block the air in-flow and reduced the background intensity at 340 nm region (NH band). Emission intensity was measured for determination of halogen element in the aqueous solution with power and carrier gas flow rate. Electron number density and the excitation temperature were on the order of $3.67{\times}10^{11}/cm^3$ and 4,350 K, respectively. These values are similar or a bit smaller than other microwave plasmas. It has been possible to analyze aqueous samples. The detection limit for Cl (479.45 nm) was obtained to be 116 mg/L and needs analytical optimization for the better performance.