• Textile Coloration and Finishing
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• v.13 no.6
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• pp.9-9
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• 2001

The preparations of deodorizing fibers using metalloporphyrines have been investigated. The three metalloporphyrin derivatives(MTCPP, M=Mn, Zn, Sn) were prepared in modest to good yields. The metalloporphyrin derivative as a deodorant material was introduced to fibers by a dyeing method. The deodorant activity(D.A.) of these deodorizing fibers was measured by chromogenic gas detector tubes. In comparison with untreated fiber, these deodorizing fibers was remarkably effective against NH₃ and CH₃SH. More than 98% of ammonia can be removed within 20 min.. The D.A.(%) of fiber adsorbed MTCPP was more than 80% after 90min..

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.37-45
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• 2013

The aim of this study was to investigate chemical characteristic of livestock compost in association with livestock manure types (poultry, cattle, swine, and mixed manure). The livestock compost was collected from local nonghyup branches on a si-gun level. Chemical composition (nutrients, heavy metals etc.) of the samples was analyzed and Pearson's correlation analysis was performed. Quality of most compost samples met the standard of fertilizer specifications. Poultry compost contains greater nutrients especially $P_2O$ (p-value<0.01) and $NH_4$-N (p-value<0.05). Meanwhile swine compost has higher concentration in water content (p-value<0.05) and heavy metals (p-value<0.01 for Cd, Cu and Zn). Overall, poultry compost was correlated positively with nutrients while swine compost has positive correlation with water content and heavy metals. We expect that the study results can provide base data for determining compost types and amount for crop production.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.347-351
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• 1997

A micromachined piezoelectic cantilever transducer,which works both as a microphone and as a microspeaker,has been fabricated and tested. The 2000*2000*3.mu.m .sap2. cantilever has oxide(ZnO)piezoelectric thin film on a supporting layer of low-pressure chemical-vapor-deposited(LPCVD)low-stress siliconnitride. A highlight of the fabrication process which may also be relevant for other micromachined stuctures is the technique for producing a flat,multilayer cantilever. The measured microphone sensitivity is fairly constant at 2 mV/.mu.bar in the low frequency range and rise to 20 mV/.mu.bar at the lowest resonant frequency of 890 Hz. The 2 mV/.mu.bar sensitivity is the highest report to data for a microphone with a micromachined diaphragm. When measured into a 2 cm/sap3 coupler with 4V (zero-park)drive,the microspeaker output sound pressure level(SPL) is 75 dB at 890 Hz. It increases to approximately 100dB SPL at 4.8kHz with 6V(zero-park)drive. The measured microphone frequency response agrees well with the results of an ABAQUS simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.753-753
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• 2008

Magneto-rheological elastomers(MRE) are similar to magnetorheological fluids. Thus, rheological properties of MRE can be also controlled by an applied magnetic field. The MRE in this experiment is a mixture of natural rubber(NR), carbonyl iron powder(CIP), ZnO, and sulfur. Three specimens were prepared and tested by using the vibration testing instruments. The magnetic field was generated by the electromagnets. Natural frequencies of the oscillator were changed by the applied magnetic field. The properties of the MRE were increased due to magnetic field strength.

• Proceedings of the Korean Vacuum Society Conference
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• 2004.08a
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• pp.226-226
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• 2004

• Journal of the Korean Ceramic Society
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• v.28 no.1
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• pp.74-78
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• 1991

Willemite powders which have been prepared by solid state reaction were easy to intermixed impurities, and particle surfaces were demaged in the progress of crushing. The above defacts were easy to accompany non-crystallization for mechanochemical effects and luminescence efficiency was deteriorated. The goal of this study improve each of defacts, and synthesize high purity and fine Mn doped willemite powders by wet and hydrothermal methods without crushing progress. It has been experimentally verified that the single phase Zn1.98Mn0.02SiO4 willemite powders which prepared by hydrothermal synthes is at 220$^{\circ}C$ for 10 hours in 2N KOH solution. The products are like needle and composition is the same with starting composition.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1091-1097
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• 2014

Tageteserecta flower like zinc oxide nanostructures composed of hexagonal nanorods were synthesized via sonochemical method at room temperature. The synthesized nanomaterials exhibited wurtzite hexagonal phase structure with the single crystalline nature. The diameter of the individual nanorods that constitute the flower shaped zinc oxide structures is in the range of 120-160 nm. The sonication time effectively determined the morphological properties of the prepared materials. The catalytic activity of prepared zinc oxide nanostructures towards N-formylation reactions were evaluated without any surface modification and the nanostructures exhibited good reaction yield with the prompt recyclability behavior.

• Korean Journal of Metals and Materials
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• v.48 no.6
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• pp.565-569
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• 2010

We report on the characteristics of indium-oxide-doped ZnO (IZO) ohmic contact to p-GaN. The IZO ohmic contact layer was deposited on p-GaN by a Roll-to-Roll (RTR) sputter method. IZO contact film with a thickness of 360, 230 and 100 nm yielded an ohmic contact resistance of $4.70{\times}10^{-4}$, $5.95{\times}10^{-2}$, $4.85{\times}10^{-1}\;{\Omega}cm^{2}$ on p-GaN when annealed at $600{^{\circ}C}$ for 1 min under a nitrogen ambient, respectively. While the transmittance of IZO film with a thickness of 360 nm slightly increased in the wavelength range of 380-800 nm after annealing, the transmittance rapidly increased up to 80% after annealing at $600{^{\circ}C}$ in the wavelength range of 380~430 nm because the crystallization of IZO film and created Ga vacancies near the p-GaN surface region were affected by the annealing. These results indicate that ohmic contact resistance and transmittance of the IZO films improved.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.339-341
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• 2009

Surge Protective Device(SPD) is installed by increasing information and communication equipments and home network equipments by individual home, and the amount of SPD used is increasing by revision industry regulations and strengthening equipotential grounding system. Parts of SPD installed in residential distribution board has ZnO varistor, voltage constraint type devices, but it is exposed to Temporary Overvoltage Characteristic. This thesis analyzes products through Thermal Stability test for SPD for general house and suggests the better method. As results of analysis, Gas Discharge Tube(GDT) to cut off from a leakage current and more than two kinds of safety devices to protect Thermal Runaway were needed.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.79-84
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• 2004

The existing technological schemes for processing rhenium-containing raw materials involve the recovery of Re from solutions, which can be effectively achieved by anion exchange method. The application of anion exchange also allows to study rhenium state in aqueous solutions and to develop analytical control methods. The present work is focused on investigation of ion exchange equilibrium in the analytical system Re(VII)-HCl-$SnCl_2$-KSCN-anion exchanger by means of sorption-desorption method as well as by electron, IR- and diffuse reflection spectroscopy. It was shown that rhenium can be quantitatively recovered from this system. It is proposed to use the sorption-spectroscopic method for Re(VII) determination in aqueous solutions. The calibration curve is linear in the concentration range of 0.5-20.0 mg/L (sample volume is 25.0 mL) and the detection limit is 0.05 mg/L. The presence of Mo(VI), Cu(II), Fe(II, III), Ni(II), Zn(II) as well as $K^+,\;Na^+$ do not hinder the solid-phase determination of rhenium. Rhenium (VII) determination by diffuse reflection spectroscopy was carried out in model solutions as well as in samples of river-derived water and in solutions obtained after the dissolution of spent catalysts.