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Purpose: This is a descriptive study that provides basic material to improve occupational health nurses' work conditions and industrial performance status. Methods: The 955 nurses who participated in the training program to understand the purpose of this study from January 2009 to December 2010 conducted by the Korean Association of Occupational Health Nurses agreed to be subjects for the study. The questionnaire included the general characteristics, work conditions and performance of occupational health management. The data were analyzed using descriptive statistics, t-test, ANOVA, and multiple regression analysis. Results: Occupational health management performance of the subjects averaged 3.11 points and detailed area by health management 3.64 points, environment management 2.91 points and occupational management 2.77 points. Health management performance of those factors affecting the duration of occupational health nurse (β=.199), type of industry (β=.126), average annual income (β=-.277) to 11.4% (F=3.175, p

Carbonate apatite has a similar structure to the inorganic component of teeth and bone. Although carbonate apatite is widely used as a bone substitute, there are no reports on its use as a desensitizing dentifrice. This in vitro study evaluated the relative abrasivity of the dentifrice containing nano-sized carbonated apatite (n-CAPs) using a Surface Profile Method (SPM). The dentin specimens were made from the root of extracted human molars. The cervical part of the teeth was sectioned with a diamond wheel disk. The teeth were embedded into an epoxy resin mold and the surface was gradually polished using silicone carbide paper. After grinding, the degree of surface roughness was examined within the range of 2 mm with tapping. The British Standard Institution reference dentifrice (BSI: CaCO3 40%) and the experimental dentifrices (group 1: n-CAPs 30%, group 2: n-CAPs 15% and silica 15%, group 3: n-CAPs 5% and silica 25%, group 4: silica 30%, group 5: CaCO3 10% and SrCl2 10%) were compared. The dentifrice slurries were prepared by mixing 24 grams of the dentifrice in 12 ml distilled water. Each tooth specimen was brushed 1,000 times with the dentifrice slurries using a back-and-forth stroke. The relative abrasivity of each dentifrice was evaluated by determining the ratio of the BSI standard dentifrice to each experiment. The results were analyzed using one-way ANOVA and Tukey’s multiple comparisons using Window SPSS (Statistical analysis system) 12.0. According to the results, Group 1 (3.2), which contained only n-CAPs appeared to have the lowest abrasivity than the BSI dentifrice (100). However, Groups 2 (124.2), 3 (137.9) and 4 (178.1), which contained n-CAPs and silica, appeared to have a higher abrasivity than the BSI dentifrice (p>0.05). The relative abrasivity of group 5 (38), which was a commercial desensitizing dentifrice, was relatively lower. It appears that the higher abrasivity of the experimental is due to the shape and size of the silica component. Therefore, n-CAPs itself has no influence on the abrasivity of the dentifrice. The main reason for the low abrasivity of n-CAPs is believed to be its small particle size (range 50-90nm).

LSGM is known to have a critical limit in terms of its application due to its chemical reactivity with other unit cell components. In particular, the formation of a highly resistive La–Sr–Ga–O phase at the interface of the anode and electrolyte poses a major obstacle toward the application of LSGM-based SOFCs. In this study, we investigated the interfacial reactions in LSGM-based SOFCs under various fabrication conditions in order to identify a means of avoiding or diminishing undesirable interfacial reactions. The electrical properties and phase composition of all reaction products were analyzed with the DC 4-point probes technique and X-ray diffraction. Microstructural evolution due to the chemical reactions between unit cell components was characterized with Environmental Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy. According to the analysis of the interfacial reaction, a serious reaction zone exists, critically increasing the internal ohmic resistance of the cells. Moreover, this interfacial reaction decreases the OCV (open cell voltage) and consequently deteriorates the unit cell performance. Possible approaches to solving this reaction problem are reducing the heat-treatment temperature or introducing an effective buffering layer to prohibit interfacial reaction.

CoOx/CeO2 catalysts of different cobalt loading have been prepared and tested for carbon monoxide oxidation in stoichiometric mixtures of carbon monoxide and oxygen. They were investigated by TPR, CO-TPD and XPS. The finely dispersed CoOx species that can absorb carbon monoxide seemed to be important in determining the catalytic activity.

The effect of potassium addition to alumina supported vanadium catalysts on the catalytic activity for the selective oxidation of H2S is investigated. XRD, XPS and XANES have been used to characterize a series of K-V/Al2O3catalysts. The enhanced sulphur yield has been correlated with the crystallinity of vanadium.

A two-stage CO 2 hydrogenation reaction was conducted to increase methanol yield. At the first-stage, CO 2 was converted to CO by the reverse water-gas shift reaction with Cu/ZnO/Al 2 O 3, , Fe 2 O 3 /Cr 2 O 3 , or MoS 2 /TiO 2 catalyst, and then at the second-stage, methanol was synthesized from the effluents of the first-stage with a commercial methanol synthesis catalyst, Cu/ZnO/Al 2 O 3 . In the case of the two-stage CO 2 hydrogenation reaction, CO that was produced by the first-stage reverse water-gas shift reaction contributed to the methanol synthesis, increasing the methanol yield. Especially, with the two-stage CO 2 hydrogenation reaction, methanol yield obtained was two or three times higher than that of the single-stage one. It was found that to increase the methanol yield in the two-stage hydrogenation reaction, more CO 2 should be converted to CO at the first-stage. The XRD patterns of the Cu/ZnO/Al 2 O 3 catalyst before and after reaction showed the presence of metallic bulk Cu and the absence of other bulk Cu species.

Highly dispersed nickel–titania composite aerogel catalysts have been prepared by CO 2 supercritical drying of alcogels obtained by the sol–gel process. The effect of heat treatment conditions on the textural and structural properties of the resulting aerogels was investigated by nitrogen adsorption–desorption, TG/DTA, XRD and TEM. The nickel–titania composite aerogel calcined and reduced under carefully controlled conditions exhibited an excellent catalytic performance for the liquid-phase hydrogenation of benzophenone to benzhydrol.

Objective: This study was conducted to evaluate the potential of a novel trifunctional methacrylate as a component of a photocurable composite resin with reduced curing shrinkage. Methods: Tris[4-(2′-hydroxy-3′-methacryloyloxypropoxy)phenyl]methane (TTEMA) was synthesized by reacting triphenylolmethane triglycidyl ether (TTE) with methacrylic acid in the presence of 4-(dimethylamino)pyridine. Photopolymerization reactivity and volumetric shrinkage of unfilled resins based on TTEMA were investigated by Fourier transform infrared spectroscopy and density measurements, respectively, and the results were compared with those for conventional dental monomers. A three-point bending test of the TTEMA-containing composite resin was carried out. Results: TTEMA was easily prepared in a good yield of 89%. Unfilled resins of TTEMA and bis-GMA, each containing 40% TEGDMA, showed similar photopolymerization reactivity. TTEMA exhibited a very low photopolymerization shrinkage of 2.09%, and 3:2 TTEMA–TEGDMA unfilled resin revealed 10% lower shrinkage than a conventional bis-GMA system containing the same amount of TEGDMA. The flexural strength of a light-activated composite resin formulated with TTEMA is comparable to that of a bis-GMA composite resin under the same conditions. Significance: TTEMA is promising for application as a photocurable dental monomer due to ease of synthesis, good polymerization reactivity, and relatively low curing shrinkage.

Addition of a second metal often improves the selectivity of a supported catalyst for the hydrogenation of 1,3-butadiene. Catalysts containing 15 wt% Ni and varying amounts of Cu were prepared and characterized by TPR, XRD and XPS. The Cu-Ni interaction affects the reduction behavior of the catalysts. TPR result shows that the synergetic effect of copper and nickel modifies the capability of metal to combine with hydrogen in bulk phase. The Ni 2p spectra in XPS shows significant shifts toward lower binding energies with increasing copper loading. From XRD results it is represented that aggregation of nickel occurs more easily due to the copper addition. The adding of copper on Ni/Al 2 O 3 makes the conversion rate decreased and increases the selectivity to 1-butene.

Ceria-supported copper-palladium catalysts have been tested in the hydrogenation of 1,3-butadiene. The SMSI behavior of the bimetallic catalysts depended on the temperature of reduction. They were analyzed by H2 chemisorption and XPS.

A commercial activated carbon was used as catalyst support in Pd/AC catalysts. The effects of the different surface oxygen groups and textural properties of the carbon supports on the metal dispersion of the supported catalysts were analyzed.

Mesoporous and well-dispersed nickel–alumina composite aerogels with high surface area have been prepared by CO 2 supercritical drying of alcogels obtained by the fast sol–gel process. They were evaluated as catalysts in a batch reactor for the liquid-phase hydrogenation of benzophenone and soybean oil and showed excellent activity and accessibility of the metal particles. They were also characterized by nitrogen adsorption–desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) to explain their excellent catalytic performance in comparison with other alumina-supported nickel catalysts.

To abate NO in exhaust, a series of copper-aluminate catalysts were prepared by calcination at high temperature with high surface area support. Variables were Cu loadings and calcination temperatures. Characterization results show that a copper aluminate phase is formed with spinel type structure through high calcination temperature and copper loading. The activity and stability for NO reduction were studied in a lab. scale reactor in the presence of excess oxygen. The reducing agent was C3H6 or NH3. The catalyst, calcined at high temperature showed enhanced activity in the presence of C3H6, but copper aluminate species, formed by calcination at high temperature, have no effect on NO conversion when NH3 is used as the reducing agent. Engine dynamometer test showed that C3H6 is more effective than C2H5OH to abate nitric oxide with 10 wt.% copper loaded aluminate catalysts.

This research has explored the effect of adding potassium to nickel supported on γ-alumina in the selective hydrogenation of 1,3-butadiene. The catalysts containing 15 wt% Ni and varying amounts of K ((K/Ni+K)atomic = 0.2-0.6) were prepared by impregnation and characterized by temperature-programmed reduction (TPR), chemisorption of H2, X-ray photoelectron spectroscopy (XPS) and X-ray absorbance near edge structure (XANES) spectroscopy. Activity and product selectivities were tested for hydrogenation of 1,3-butadiene in the temperature range of 373-673 K. The catalytic activity for the hydrogenation of 1,3-butadiene is closely related to the specific surface area of nickel metal and the crystal structure of the oxide, from which the metal was formed by reduction. The addition of potassium increased the 1-butene selectivity due to the modification of the electron density of Ni metal. It has been established that the addition of K modified the electron density of Ni metal, and this result is ascertained by a shift of the Ni binding energy in XPS measurement and Ni absorption edge in XANES spectra.

The promotion of Ag/γ-Al2O3 by adding alkali metals (Li, Na, K, Cs) for selective catalytic reduction of NO with C3H6 was studied in this work. The activity of NO reduction was enhanced by addition of Cs to Ag/γ-Al2O3 in the presence of excess oxygen and SO2. The stability and growth of silver oxide particles were promoted and the dispersion of silver particles on γ-Al2O3 was improved by the addition of 0.5 wt% Cs and 1 wt% Cs to 2 wt% Ag/γ-Al2O3, respectively. The results were confirmed by H2 TPR, UV-Vis DRS, TEM, and XPS.

The adsorption equilibrium and regeneration efficiency of n-hexane, methyl ethyl ketone (MEK), and toluene under supercritical CO2 on an activated carbon fiber were experimentally determined. When the densities of the supercritical fluids were fixed at 0.32, 0.45, and 0.62 g/cm3, the Langmuir model agreed with the experimental isotherms at the temperatures 308, 318, and 328 K. As the concentration of adsorptive in supercritical CO2 was kept constant, the crossover of the equilibrium loading at different temperatures was observed at relatively high pressure and the crossover pressure of MEK was lower than that of n-hexane. In both cases, the crossover pressure increased with an increase in concentration. Also, the activated carbon fiber loaded with toluene and MEK was regenerated by supercritical CO2 in the range of 0.69−0.90 g/cm3. Desorption became favorable with an increase in pressure, and there was an optimal temperature at every pressure condition. However, the regeneration efficiency increased with ...

CO2 reforming of CH4 was carried out over Ni–alumina aerogel catalysts prepared with various Ni loadings. The preparation of alumina supported Ni catalysts via sol–gel synthesis and subsequent supercritical drying led to the formation of very small metal particles, which are evenly distributed over the alumina support. The activity of the aerogel catalysts increased along with increasing metal loading, and eventually, the SAA25 (0.25 in Ni/Al mole ratio) catalyst exhibited the high activity comparable to that of a 5 wt.% Ru/alumina catalyst (ESCAT44, Engelhard). Compared to the alumina-supported Ni catalyst prepared by conventional impregnation method, Ni–alumina aerogel catalysts showed a remarkably low coking rate due to highly dispersed metal particles. From TEM micrograph studies, it was observed that the formation of filamentous carbon was significantly influenced by the metal particle size and proceeded mostly over the metal particles larger than 7 nm. The loss of catalytic activity at 973 K was mainly caused by coke deposition and sintering.

The effect of MoO3 addition to alumina supported vanadia catalysts on the catalytic activity for the selective catlaytic reduction of NO is investigated. Upon the addition of MoO3, catalytic activity is enhanced and the particle size of V2O5 which is shown by the results of XRD and Raman spectroscopy is decreased. The MoO3-V2O5/Al2O3 catalyst also exhibits more resistance to SO2 deactivation than V2O5/Al2O3 does.

Tungsten oxides, to be used as precursors for tungsten nitride catalysts, were prepared by a sol–gel method. The preparation conditions were as follows: the solution molar ratio of 1 : 1 (methanol and water), temperature of 80°C, and the range of R (methanol/H2WO4 mole ratio) between 15 and 30. The XRD results showed that the prepared gels were amorphous and suggested they were tungsten oxide hydrate. However, this result disagreed with that of Raman spectroscopy and XANES. The highest surface area was 28.57 m2/g, which was obtained from the tungsten oxide with the R ratio of 25. After the gel was heated at 500°C, it was crystallized tungsten oxide (WO3). The results of Raman spectroscopy and XANES showed that the unheated gel had a considerable amount of structural water in its structure. Such structural water may have an effect on nitriding the sample. Tungsten nitride catalysts were prepared in NH3 flow with the flow rate of 100 ml/min, at 670–700°C with the heating rate of 1.0°C/min by the temperature programmed reaction (TPR) method. The prepared nitride catalysts were found to be mostly s-W2N from the XRD results. The surface area of the nitride from unheated gel was 79.53 m2/g, which was higher than that of the nitride from a commercial tungsten trioxide. The temperature for nitriding the prepared gels of this present study was lower than that of the commercial tungsten trioxide.

Mesoporous nickel–alumina aerogel catalysts with high surface area have been prepared by CO2 supercritical drying of alcogels obtained by the fast sol–gel process. The nickel phase was uniformly distributed in the alumina gel network from transparent monolithic nickel–alumina co-gels by using nickel acetate as a metal precursor. The nickel–alumina aerogel catalysts prepared were characterized by nitrogen adsorption–desorption, TG/DTA, and reaction test, and their properties were compared with those of conventionally impregnated catalysts. Alumina aerogel-based nickel catalysts exhibited good activity and marked stability against coking in methane dry reforming.

A series of γ-Al 2 O 3 supported molybdenum nitride catalysts (nitrided Mov γ-Al 2 O 3 (MNS), CoMo γ-Al 2 O 3 (CMNS), and NiMo γ-Al 2 O 3 (NMNS)) and unsupported molybdenum nitride catalyst (MNUS) were prepared by the temperature programmed reaction of their corresponding molybdenum oxide precursors with NH 3 . The surface properties of prepared molybdenum nitride catalysts were characterized by N 2 adsorption, XRD, and XPS methods. N 2 adsorption and XRD studies show that the supported molybdenum nitride catalysts possess a highly dispersed surface molybdenum nitride species on the alumina support, while unsupported molybdenum nitride catalyst possesses a typical crystalline Mo 2 N (FCC) structure. The XPS data of supported molybdenum nitride catalysts reveal that Mo 2+ , Mo 3+ , and Mo 4+ species were selectively produced upon nitridation. The results of dibenzothiophene (DBT) hydrodesulfurization over molybdenum nitride catalysts show that the reactivity is strongly dependent on the type of catalysts and it decreases in the order: MNS > NMNS ≥ CMNS ≥ MNUS. In addition, it was also found that the reactivity increases when increasing the reaction temperature and pressure and contact time. No synergistic effect for DBT hydrodesulfurization over Co (or Ni) promoted, nitrided Mo γ-Al 2 O 3 catalysts is observed. The major reaction product is biphenyl and cyclohexylbenzene is next in abundance regardless of the type of catalysts and reaction conditions. The reactivity for DBT hydrodesulfurization does not correlate with amounts of CO chemisorption. The reactivity is rather well correlated with the difference in heat of adsorption between thiophene and H 2 S.

The hydrocracking and hydrodesulfurization (HDS) of n-heptane containing 0.2 mole% dibenzothiophene (DBT) were performed simultaneously using NiPtMo catalysts supported on HZSM-5, LaY and γ-Al2O3 in a high pressure fixed bed reactor. Molybdenum played an important role in both hydrocracking and hydrodesulfurization (HDS). We found that the sulfur compound, dibenzothiophene (DBT). in the reactant was adsorbed on a molybdenum site and converted to hydrogen sulfide so that the active sites of the catalysts for hydrocracking were less poisoned by DBT and the conversion of n-heptane over molybdenum impregnated catalyst was higher than that over molybdenum-free catalyst. The crystal structures of the molybdenum supported on the zeolite and γ-Al2O3 were mainly MoO2.5 (OH)0.5[021] and MoO3[210] respectively as shown by XRD analysis. The structure of MoO2.5(OH)0.5 was easily reduced to MoS2[003] during the reaction. After the reaction of 100 hours over the catalyst supported on γ-Al2O3 the crystal structure of MoO3[210] partially changed to MoO3[300] and the structure of MoS2[003] was not observed. Because of the reactant shape selectivity of zeolite, the acid and the metal sites in the intracrystalline of the catalysts supported on zeolites were less poisoned by DBT. Therefore, both hydrocracking and HDS using n-heptane containing 0.2 mole% of DBT were successfully demonstrated over the prepared catalysts.

A series of molybdenum nitride (Mo2N) catalysts were prepared by a topotactic synthesis method using a TPR (Temperature Programmed Reaction) at various conditions (temperature ramping rate, NH3 gas flow rate, final preparation temperature). The surface property and acidity of Mo2N catalysts prepared at various prepared conditions were studied by SEM, XRD, BET, FTTR and TGA. The hydrodenitrogenation (HDN) of pyridine in n-heptane over Mo2N catalyst (Al) was studied in a fixed bed continuous flow reactor (CATATEST) at the temperatures between 250–450°C , the pressure at 20–40 X 105 Pa and the contact time between 0.01-0.05 g cat.hr./ml feed. The microstructure of M02N catalyst was not changed at various preparation conditions by topotactic reaction. The XRD and BET studies showed that the extent of the crystallinity and the surface area of the prepared Mo2N catalysts increased when the final preparation temperature increased and the temperature ramping rate was lowered. In addition, from the TGA curve, the acid strength increased with the increase of the NH3 gas flow rate. The results of pyridine hydrodenitrogenation (HDN) over Mo2N catalyst showed that the catalytic activity (conversion % ) increased as reaction temperature, reaction pressure, and contact time increases. The selectivity for piperidine possessed a maximum at 350°C regardless of the reaction pressure. Also, the selectivity for cracked products increased as reaction temperature and pressure increased. The activation energy was determined 7.16 kcal/mol by Arrehenius plot.

A fast sol−gel synthetic route for obtaining alumina aerogels has been developed by modifying the tranditional method under appropriately controlled conditions. The highly mesoporous alumina aerogel prepared by our new sol−gel synthesis method and CO2 supercritical drying had a surface area in excess of 700 m2/g and high thermal stability.

A fast sol−gel synthetic route for obtaining alumina aerogels has been developed by modifying the tranditional method under appropriately controlled conditions. The highly mesoporous alumina aerogel prepared by our new sol−gel synthesis method and CO2 supercritical drying had a surface area in excess of 700 m2/g and high thermal stability.

CO 2 reforming of methane was carried out over nickel-alumina aerogel catalysts prepared with various Ni loadings. Compared with alumina-supported Ni catalyst prepared by conventional impregnation method, nickel-alumina aerogel catalysts exhibited remarkably low coking rate due to highly dispersed metal particles. From TEM studies, it was observed that the metal particle size significantly influenced the formation of filamentous carbon. Addition of potassium to the nickel-alumina aerogel catalysts appeared to improve the stability of the catalyst at 923 K while the effect was not clear at higher temperatures.

The hydroprocessing of fuels containing relatively large amounts of organonitrogen compounds becomes increasingly important in the upgrading of hydrocarbon fuels. Therefore, to investigate the removal of organonitrogen compounds, the hydrodenitrogenation of pyridine dissolved in n-heplane was studied over sulfided Ni-Mo/u-Al2O3 catalysts in the range of lemperature between 513 K and 633 K and pressure between 30 bar and 50 bar in a fixed bed flow reactor. Pyridine conversion increased with the increased temperature and pressure, and the piperidine formation was found to be irreversible. Pyridine concentration reached a maximum at about 573 K and the apparent reaction order was found to be one with respect to pyridine.

The kinetics of the hydrodesulfurization(HDS) of dibenzothiophene (DBT) has been studied over a NiO-MoO3/γ-Al2O3 catalyst in the temperature range of 473-673 K for partial pressures of DBT from 20 x 105Pa to 70 x 105Pa. A form of the Langmuir-Hinshelwood type rate equation was used to describe the kinetics of the reaction. The reaction was carried out at low conversion level to obtain initial reaction rate data. From this study the rate equation giving the best fit to the data was $$r = \frac{{k_D P_D P_H }}{{\left[ {1 + K_D P_D + \left( {K_H P_H } \right)^{1/2} } \right]^2 }}$$ , which suggests that DBT and hydrogen adsorb on the same type of active sites and that hydrogen adsorbs dissociatively.