• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.326-333
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• 1996

Dehydrogenation of 4-vinylcyclohexene(4-VCH) to ethylbenzene is elucidated via catalytic transfer hydrogenation with the heterogeneous catalyst of Pd/C. Hydrogen-donor solvent is ethanol or water. Oxidizers of the catalytic dehydrogenation reaction are mono- or dinitro compounds, $H_2O_2$, NaClOn (n=1~4), or oxygen at $70{\sim}110^{\circ}C$. The ratio of 4-VCH/Nitro compounds is 1:0.02 to 1:0.5 and 4-VCH vs. $H_2O_2$ or NaClOn (n=1~4) is 1:0.1 to 1:3.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.119-126
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• 2001

Hydrogenated amorphous carbon (a-C:H) films were deposited by ECR-PECVD (electron cyclotron resonance-plasma enhanced chemical vapor deposition) method with deposition conditions such as ECR plasma source power, gas composition of methane and hydrogen, deposition time and substrate bias voltage. The hydrogen content in the films has been measured by ERDA (elastic recoil detection analysis) using 2.5 MeV $He^{++}$ ion beam. From the results of AES (Auger electron spectroscopy), RBS (Rutherford backscattering spectrometry) and ERDA, the composition elements of deposited film were confirmed the carbon atom and the hydrogen atom. It was observed by FTIR (Fourier transform infrared) that the hydrogen contents in the film varied according to the deposition conditions. In deposition condition of substrate bias voltage, the hydrogen contents were decreased remarkably because the amount of dehydrogenation in films was increased as the substrate bias voltage increased. In the rest deposition conditions, the hydrogen contents in the film were measured in the range 45~55%.

• Resources Recycling
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• v.24 no.1
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• pp.21-27
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• 2015

The present study describes the process of producing low oxygen content alloy powder from Ti-6Al-4V and Ti-8Al-1Mo-1V (AMS 4972) alloy scraps using hydrogenation-dehydrogenation (HDH) and deoxidation in solid state (DOSS) processes. Each prepared powder was deoxidized with Ca contact and non-contact method to compare the deoxidation capability. It is known that the non-contact deoxidation method, using Ca vapor above the melting temperature $T_m$ of Ca, has greater deoxidation capability. However, Oxygen contents in Ti-6Al-4V and Ti-8Al-1Mo-1V powder after non-contact deoxidation method were higher than those after contact deoxidation method. Therefore, we investigate the effect of Al - the richest alloy element in theses Ti based metals - on the deoxidation processes.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.291-299
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• 2004

DLC films were deposited using the ECR-PECVD method with the fixed deposition condition, such as ECR power, methane and hydrogen gas-flow rates and deposition time, for various substrate bias voltage. We have investigated the ion bombardment effect induced by the substrate bias voltage on films during the deposition of film. The characteristic of the films were analyzed using the FTIR, Raman, and UV/Vis spectroscopy analysis shows that the amount of dehydrogenation in films was increased with the increase of substrate bias voltage and films thickness was decreased. Raman scattering analysis shows that integrated intensity ratio(ID/IG) of the D and G peak was increased as the substrate bias voltage increased and films hardness was increased. Optical transmittances of DLC film were decreased with increasing deposition time and substrate bias voltage. From these results, it can be concluded that films deposited at this experimental have the enhanced characteristics of DLC because of the ion bombardment effect on films during the deposition of film.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.382-388
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• 2000

Hydrogenated amorphous carbon (a-C:H) films were fabricated by electron cyclotron resonance plasma-enhanced chemical vapor deposition. The bonding structure of carbon and hydrogen in the a-C:H films has been investigated by varying the deposition conditions such as ECR power, gas composition of methane and hydrogen, deposition time, and negative DC self bias voltage. The bonding characteristics of the a-C:H thin film were analyzed using FTIR spectroscopy. The IR absorption peaks of the film were observed in the range of $2800\sim3000 \textrm{cm}^{-1}$. The atomic bonding structure of a-C:H film consisted of $sp^3$ and $sp^2$ bonding, most of which is composed of $sp^3$ bonding. The structure of the a-C:H films changed from $CH_3$ bonding to $CH_2$ or CH bonding as deposition time increased. We also found that the amount of dehydrogenation in a-C:H films was increased as the bias voltage increased.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.328-334
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• 2000

DLC (Diamond-Like Carbon) films were deposited by ECR-PECVD (electron cyclotron resonance plasma-enhanced chemical vapor deposition) method with the variation of substrate bias voltage under the others are constant except it. We have investigated the ion bombardment effect induced by the substrate bias voltage on films during the deposition of film. The characteristics of the film were analyzed using the Dektak surface profiler, SEM, FTIR spectroscopy, Raman spectroscopy and Nano Indentation tester. FTIR spectroscopy analysis shows that the amount of dehydrogenation in films was increased with the increase of substrate bias voltage and films thickness was decreased. Raman scattering analysis shows that integrated intensity ratio $(I_D /I_G)$ of the D and G peak was increased as the substrate bias voltage increased, and films hardness was increased. From these results, it can be concluded that films deposited at this experimental have the enhanced characteristics of DLC because of the ion bombardment effect on films during the deposition of film.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.215-221
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• 2014

A simple heterogeneous system has been developed by using base treated manganese dioxide (B-$MnO_2$) for the aerobic oxidation of amines under mild reaction conditions of 1 atm of air and $50^{\circ}C$ in hexane. This system was highly efficient to oxidize various kinds of primary or secondary amines including aliphatic, aromatic, and hetero-atomic ones under the applied reaction conditions. Amines were oxidized to nitriles or diimines by the self-condensation or oxidative dehydrogenation through imine intermediate. The B-$MnO_2$ was reused for at least 5 times without any loss of its catalytic performance and showed its cost effectiveness, easy workup, and easy separation of the products for achieving the protocol of green chemistry.

• Journal of Hydrogen and New Energy
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• v.28 no.5
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• pp.447-452
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• 2017

A $Pd/TiO_2$ catalyst was prepared by a conventional impregnation method, and further characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. The as-prepared material was employed to accelerate dehydrogenation of potassium formate in the presence of light at different temperatures. The $Pd/TiO_2$ catalyst showed distinct dehydrogenation activities, and particularly, the material exhibited a higher turnover frequency (TOF) of $2,097h^{-1}$ at $80^{\circ}C$ after 10 minutes in the presence of light compared to that (TOF of $1,477h^{-1}$) obtained in the absence of light. Numerous analytical techniques suggest that the increased dehydrogenation activity likely originates from light-excited electron and hole at the photocatalyst, i.e., $TiO_2$, in conjunction with metal-support interaction.

• KSBB Journal
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• v.9 no.3
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• pp.319-324
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• 1994

A biosensor for the measurement of malate has been constructed by the sodium-alginate immobilized bundle sheath cell tissue of corn leaf containing malate dehydrogenase (decarboxylating) (EC 1. 1. 1. 40) on the CO2 gas-sensing electrode. The proposed tissue sensor had the linear in the range of malate concentration $5.5{\times}10^{-5}M∼2.5{\times}10^{-2}M$ with a slope of 53.5 mV/decade in 0.02M Tris-HCl buffer solution at optimum pH 8.0, and $25^{\circ}C$. A response time was 16∼18min. The present L-malate sensing tissue sensor is stable for more than one week. At pH 7.4, Km value was $0.6{\times}10^{-5}M$. The various kinds of salt did not effect the signal of malate tissue biosensor as the inhibitor. We can measure the malate by the CO2 electrode at the pH=8.0. Thus, the proposed tissue sensor will be useful for the measurement of malate.

• Journal of Hydrogen and New Energy
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• v.17 no.2
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• pp.125-132
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• 2006

The alloys which compositions were represented by the formula, $Ti_{(0.22+X)}Cr_{(0.28+1.5X)}V_{(0.5-2.5X)}$ ($0{\leq}X{\leq}0.12$), had the total hydrogen storage capacity higher than 3 wt% and the effective hydrogen storage capacity higher than 1.4 wt%. Particularly, among all the tested alloys, the $Ti_{0.32}Cr_{0.43}V_{0.25}$ alloy exhibited the best effective hydrogen storage capacity of 1.65 wt%. Furthermore, the reversible bcc${\leftrightarrow}$fcc structural transition was observed with hydrogenation and dehydrogenation, which predicted the possibility of pressure cycling. EDS analysis revealed micro-segregation, which suggested the necessity of microstructure homogenization by heat treatment. The $Ti_{0.32}Cr_{0.43}V_{0.25}$ alloy was selected for heat treatment and for other related studies. The results showed that the total and the effective hydrogen storage capacity increased to 3.7 wt% and 2.3 wt%, respectively. The flatness of the plateau region was also greatly improved and heat of hydride formation was determined to be approximately -36 kJ/mol $H_2$.