• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.532-538
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• 2006

The carbonization and activation conditions for the PAN-based ACF of various grade were investigated to obtain the optimun activation condition with high surface area. And the surface properties and the absorption performance of toxic gas for terror were examined toward the PAN-ACF with the highest surface area. In the test results the surface area increased with increase of the activation temperature, but decreased with increase of the carbonization temperature. After carbonization condition ($900^{\circ}C$-15min) and activation condition ($900^{\circ}C$-30 min), we got the ACF with the highest surface area of $1204m^2/g$. In the absorption test of iodine and toxic gas for terror, this ACF showed more excellent absorption performance than the existing carbon-based adsorbent. Also, in order to give the function characteristic for a selective absorption, the stable nanoparticles of the Ag, Pt, Cu, Pd were prepared and impregnated on the PAN-based ACF in replacement of the existing method supporting metal catalysis. And were analyzed the surface characteristics and the $SO_{2}$ adsorption characteristics. In the $SO_{2}$ absorption performance test of the PAN-ACF with the impregnated nanoparticles, it wasn't change breakthrough time of Ag, Pt, Cu nanoparticle supported the PAN-ACF comparing with breakthrough time (326 sec) of the non supported PAN-ACF but Pd nanoparticle supported the PAN-ACF achieved excellent $SO_{2}$ absorption performance which has break-through time 925 sec.

• Clean Technology
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• v.15 no.1
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• pp.9-15
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• 2009

Catalytic hydrodechlorination of PCBs (polychlorinated biphenyls) included in the transformer oil was carried out to detoxify PCBs and to recycle the treated oil. Catalysts such as 0.98 wt% Pt and 0.79 wt% Pd on ${\gamma}$-alumina (${\gamma}-Al_2O_3$) support, 12.8 wt% Ni on ${\gamma}-Al_2O_3$, and 57.6 wt% Ni on silica-alumina ($SiO_2-Al_2O_3$) support were used for the catalytic hydrodechlorination. Various supercritical fluids such as carbon dioxide, propane and isobutane were used as reaction media. The effects of reaction temperature, reaction time, catalysts, and supercritical fluids on the catalytic hydrodechlorination were examined in detail. The detoxification degree increased in the order of Ni > Pd > Pt. This is possibly due to higher metal loading and larger metal size of the Ni catalyst. Below $175^{\circ}C,\;scCO_2$ was found as the most effective reaction media for the catalytic hydrodechlorination of PCBs included in the transformer oil.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2539-2545
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• 2012

In the present study, we suggest a new way to reactivate performance of direct formic acid fuel cell (DFAFC) and explain its mechanism by employing electrochemical analyses like chronoamperometry (CA) and cyclic voltammogram (CV). For the evaluation of DFAFC performance, palladium (Pd) and platinum (Pt) are used as anode and cathode catalysts, respectively, and are applied to a Nafion membrane by catalyst-coated membrane spraying. After long DFAFC operation performed at 0.2 and 0.4 V and then CV test, DFAFC performance is better than its initial performance. It is attributed to dissolution of anode Pd into $Pd^{2+}$. By characterizations like TEM, Z-potential, CV and electrochemical impedance spectroscopy, it is evaluated that such dissolved $Pd^{2+}$ ions lead to (1) increase in the electrochemically active surface by reduction in Pd particle size and its improved redistribution and (2) increment in the total oxidation charge by fast reaction rate of the Pd dissolution reaction.

• Journal of the Korean Magnetics Society
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• v.18 no.5
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• pp.190-194
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• 2008

Epitaxial $L1_0$ FePd (001) thin films were successfully manufactured by sputtering deposition method. The structure and magnetic properties of FePd thin films were characterized as a function of Fe compositions. It was found that the long-range ordering parameter had a maximum for the stoichiometric composition, whereas the magnetic anisotropy had a maximum as the Fe content is decreased to slightly above the stoichiometric composition. This indicates that the stoichiometry is directly contributed to the chemical ordering and the magnetic anisotropy. These results imply that nonstoichiometric FePd compositions, with a slight excess of Pd, may in fact be preferred for applications that require high magnetic anisotropy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.286-292
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• 1986

For the elucidation of saponin synthesis during ontogeny changes of ginsenosides and free sugars in seeds during stratification and seedlings in early growth stage were investigated with high performance liquid chrom-atography. Embryo plus endosperm at 40-day stratification showed 80% decrease of total saponin, disappear-ance of Rc, Rb$_2$ and Rb$_1$ and appearance of Rg$_3$ (probable) and 20-Glc-Rf (probable). Leaf ginsenoside F$_3$ was found not in fruit plup but seed and decreased during stratification. Both decomposition and synthesis of saponin seemed to occure during stratification. Ginsenosides in endosperm and embryo might be originated from fruit pulp by penetration. In seedling saponin appeared first in shoot and in root about one month later. Ginsenoside Rc, Rb$_2$, Rb$_1$ appeared in root at the last investigation (June 30) indicating normal saponin synthetic capacity of root. Saponin synthetic rate was twice in leaf than in root. Leaf ginsenoside F$_3$ was found in seedling root. Root saponin Rg$_3$ and 20-Glc-Rf were found in leaf and stem in seedling and decreased with growth suggesting that rate saponin is not such in certain growth stage. Total saponin content was negatively correlated with PT/PD in seeds and arial parts of seedling due to greater change of PD. than PT. Seed at 70days stratification showed high sucrose content. In seedling glucose was main sugar in stem all the while and sucrose in root at early stage while glucose, fructose and sucrose were found in leaf.

• Korean Journal of Veterinary Service
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• v.33 no.1
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• pp.67-74
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• 2010

To reduce an economic loss by swine disease, this study was designed to provide helpful data which are particularly useful for each individual farm. From february to December 2009, a total of 18,173 slaughter pigs (612 herds) were randomly sampled, which were produced just in southern region of Gyeonggi-do. We examined all of them for the slaughter lesions of 8 kind diseases such as swine enzootic pneumonia (SEP), pleuritis (PL), pleuropneumonia (PP), white milk spot in liver (WMS), papular dermitis (PD), pericarditis (PC), ileitis (IL) and peritonitis (PT). Twenty four percentages (4431/18173 pigs) of the examined pigs had no lesions about 8 kind diseases. Among the pigs with lesions, the numbers of the pigs with just one lesion were 7,637(42%), followed by 4,551(25%) pigs with 2 lesions. Average prevalence of pigs were 56.5% (10288/18173 pigs) in SEP, followed by 34% in PL, 12.4% in PP, 10.1% in WMS, 6.1% in PD, 4.7% in PC, 0.1% in IL and PT, respectively. Each prevalence of SEP, PL, PP and PD was higher in spring than in winter, respectively (P<0.01). Among the pigs (n=6,105) with 2 or more than 2 kinds of lesions the top (55.5%) was the pigs with SEP and PL, and the second was 1,179 (19.3%). Swine enzootic pneumonia was considered as one of the more likely risk factors for initiation or/and acceleration of other diseases such as PL, PP, WMS and PD. The lesion of SEP was relatively severe since the pigs with late stage were more (7,277 pigs) than those with early stage.

• Journal of Sensor Science and Technology
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• v.3 no.3
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• pp.9-15
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• 1994

Catalytic combustible gas sensors were fabricated by using ${\gamma}-Al_{2}O_{3}$ with large surface area and noble metal catalysts. The optimum conditions for ${\gamma}-Al_{2}O_{3}$ fabrication were investigated by DT/TGA and XRD analyses and it was found that fabricated ${\gamma}-Al_{2}O_{3}$ had superior value as surface area of $215.5m^{2}/g$. Gas sensors were manufactured and tested to inflammable gases by using Pt coil as a heater and temperature sensing part, fine ${\gamma}-Al_{2}O_{3}$ powder as a bead material and Pt, Pd noble metal powder as a catalyst. From the results, fabricated sensor showed good sensitivity to LPG and LNG of 20mV/l000ppm, 6.5mV/l000ppm respectively.

• Korean Journal of Psychosomatic Medicine
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• v.6 no.1
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• pp.59-69
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• 1998

Objectives: This research was performed to know severity of depression and anxiety, the psychopathology of hemodialysis patients and kidney transplantation patients using Minneesota Multiphasic Personality Inventory(MMPI) and Zung's Self-rating Depression Scale (SDS), Zung's Self-rating Anxiety Scale(SAS), MMPI Subscales. Methods: We surveyed 31 hemodialysis patients and 119 kidney transplantation patients. 119 kidney transplantation group(KT) was investigated at ; 1) Before kidney transplantation (KT-1), 2) Three days after kidney transplantation(KT-2), 3) Three weeks after kidney transplantation(KT-3),4) Follow up at OPD(F/U). Results: 1) According to dermographic data, mean age was KT 33.1, HD 42.2, Control 33.1 years old and KT, HD were belonged to lower economic states and lower educational level than Control. 2) In the depression scale for SDS, KT-1 was more depressed than F/U and Control but depression scale was significantly decreased at KT-2 in comparison with HD. In the anxiety scale for SAS, KT-1 was more anxious than Control but anxiety scale was not different within IT subgroups and in comparison with HD. 3) In comparison of MMPI scales, Hs, D, Pt, Ma at KT-1, Pd, Pa, Pt, Ma at KT-2, F, D, Pd, Pt, Pa, Sc, Ma at KT-3, Pt at F/U were more high scores than Control.

• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.278-287
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• 2017

In this study, lignin was efficiently degraded via two-step catalytic cracking process and lignin-oil, char, and gas was produced as lignin degraded products. Three kinds of catalysts (MgO, CaO, and Pt/C) were used in first catalytic cracking step and the highest lignin-oil yield (76.2 wt%) was obtained in Pt/C catalyst with the smallest char formation (4.1 wt%). GC-MS/FID analysis revealed that 18 kinds of monomeric phenols existed in lignin-oil and sum of them was the highest in Pt/C condition (97.8 mg/g lignin). Meanwhile, relatively lower yield of monomeric phenols was produced in MgO and CaO condition because of their absorption on catalysts. Lignin-oil produced over Pt/C was introduced to second catalytic cracking process with porous Pd/activated carbon aerogel catalyst. From this process, four kinds of monomeric phenols such as 4-ethylguaiacol, 4-propylguaiacol, 4-ethylsyringol, 4-propylsyringol were selectively produced at 0.89 - 1.82 wt% level.

• Analytical Science and Technology
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• v.15 no.3
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• pp.263-269
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• 2002

After porous filters were manufactured using cordierite powder whose mean particle size was 200 ${\mu}m$, they were loaded with catalysts such as Pt, Pd, Cu, Co, La, $V_2O_5$ by vacuum impregnation method. And we investigated the activity of catalysts used for catalytic oxidation of VOC by passing toluene through catalyst-loaded filters. The porous filters had the apparent porosity of 62%, the compressive strength of about 10 MPa and the pressure drop of 15 mmHg at the face velocity of 5 cm/sec. The loading of catalyst decreased the porosity of the filters and increased the pressure drop and the compressive strength of them. Among the catalysts, Pt had the highest activity for catalytic oxidation and could remove more than 90% of toluene at 250 $^{\circ}C$. Below 250 $^{\circ}C$, the content of Pt catalyst had an influence on the conversion of toluene but didn't show any influence above 250 $^{\circ}C$.