• Textile Coloration and Finishing
• /
• v.22 no.4
• /
• pp.362-372
• /
• 2010

This paper surveys the physical properties of the multiwall carbon nanotube (MWNT) and polyurethane composite film for improvement of mechanical properties and electrical characteristics. The modification of MWNT was carried out by acid treatment with nitric and sulphuric acid mixed solution, and then followed by thermal treatment for enhancing MWNT dispersion with polyurethane. This modified MWNT was mixed with polyurethane by changing the loading content of MWNT and dispersion time under the dimethylformamide solution in the ultrasonic wave apparatus. Various physical characteristics of the modified PU/MWNT films were measured and analyzed in terms of the loading content and dispersion time. The maximum absorbance of the PU/MWNT films were observed with the 2wt% loading at dispersion times of 2 and 24 hour, respectively. The minimum electrical volume resistivity of PU/MWNT film was shown at the loading content of 0.5wt% or more irrespective of dispersion treating time. However the optimum condition was assumed to 2wt% loading at dispersion time of 2 hours by assessing the surface profile of the film using video microscope. The breaking stress and strain of the PU/MWNT film decreased with increasing loading content, but no change of physical properties was shown with increasing in dispersion time.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.9
• /
• pp.988-993
• /
• 2004

Luminescence characteristics of Ag-doped ZnO as the quantum dot materials to increasing the efficiency on dye-sensitized solar cells (DSC) have been studied. Ag doped ZnO powder was produced by the self-sustaining combustion process using ultrasonic spraying heating method. Luminescence wavelength region of the ZnO by Ag doping was shifted to longer wavelength. Tn the case of the Ag doped ZnO powder, broad luminescence spectrum centered on 600nm was observed. On the other hand, we compared PL data of RTA treated ZnO:Ag film at various temperatures because the front electrode of solar cell was in need of the sintering process. In XRD and PL data for RTA treated film at the 500$^{\circ}C$ showed good property. And, it was found that the grain size wasn't growing but only optical property was changed. According to the result of XRD, PL, absorption, emission spectrum and DV-X${\alpha}$ used in theoretical calculation, it is considered to be possible to use Ag doped ZnO as quantum dot material for improving DSC efficiency.

• Korean Journal of Materials Research
• /
• v.12 no.9
• /
• pp.735-739
• /
• 2002

$(Y,Gd)BO_3$: Eu, $Zn_2$$SiO_4$ : Mn and $BaMgAl_{10}$ $O_{17}$ : Eu phosphors used in PDP were continuously irradiated by vacuum ultra violet generated from the penning gas (96%Ar+4%Xe) discharge and then the change of emitting intensity with time was investigated. The brightness of these phosphors decreased exponentially with VUV excitation time. The experimental data showed that the degradation rate increased in the order of $Zn_2$$SiO_4$ : Mn>(Y,Gd)$BO_3$: Eu>$BaMgAl_{10}$ $O_{17}$ : Eu phosphor. This different degradation property of phosphors was interpreted in terms of brightness saturation and stability against VUV irradiation. It was found that the degradation property of $(Y,Gd)BO_3$ : Eu red phosphor synthesized by ultrasonic thermal spray was superior to commercial phosphor.

• Korean Journal of Materials Research
• /
• v.32 no.1
• /
• pp.1-8
• /
• 2022

In this investigation, Bi₂MoO₆ deposited graphene nanocomposite (BMG) was synthesized using a simple microwave assisted hydrothermal synthesis method. The synthesized BMG nanocomposite was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy with energy dispersive X-ray analysis, and photocurrent analysis. The study revealed that the catalysts prepared have high crystalline nature, enhanced light responsive property, high catalytic activity, and good stability. XRD results of BMG composite exhibit a koechlinite phase of Bi₂MoO₆. The surface property is shown by SEM and TEM, which confirmed a homogenous composition in the bulk particles of Bi₂MoO₆ and nanosheets of graphene. The catalytic behavior was investigated by the decomposition of Rhodamine B as a standard dye. The results exhibit excellent yields of product derivatives at mild conditions under ultrasonic/visible light-medium. Approximately 1.6-times-enhanced sono-photocatalytic activity was observed by introduction of Bi₂MoO₆ on graphene nanosheet compared with control sample P25 during 50 min test.

• Geophysics and Geophysical Exploration
• /
• v.16 no.4
• /
• pp.250-256
• /
• 2013

Using shear wave velocity is more reasonable to estimate strength and integrity of rock compared with using compressional wave. It is often ambiguous to pick the dominant frequency caused by torsional wave when evaluating $V_S$ of rock specimen from FFRC method. It is also sometimes ambiguous to pick the first arrival point of S wave compared with P wave in the signals acquired from ultrasonic velocity method. Otherwise, the procedure of evaluating $V_P$ using ultrasonic velocity method and $V_L$ using FFRC method is relatively stable. Through the relationship between elastic modulus, poisson's ratio and $V_S$ can be obtained from $V_P$, $V_L$. Applicability was checked using model specimens having different material property and length and rock specimens sampled in mine area, and usefulness of proposed procedure was verified.

• Journal of Conservation Science
• /
• v.27 no.4
• /
• pp.395-401
• /
• 2011

After pressurized impregnation treatment, which has been proposed as an effective conservation method for stone cultural property, was executed with methyl metacrylate (MMA), MMA-butyl acrylate (PMB73) mixture and MMA-vinyl trimethoxy silane (PMV5) co-monomer mixture, the physical-chemical properties on the sand stone and the granite impregnated were evaluated. Compared to the case of granite, the impregnation ratios of sand stone showed larger values in the range of 3.2 to 3.7 wt% and these were increased up to 32% when the decompression process was applied to autoclave. The physical properties of sand stone such as anti-moisture property, flexural strength, impact property and ultrasonic velocity were also higher values than those of granite, which can be interpreted by high impregnation ratio resulted in many void within sand stone. The impact failure energy was 1.22 J for PMMA, 1.84 J for PMB73, and 2.8 J for PMV5, respectively. Since the inorganic affinity of treatment agent is more effective than the molecular structure of acrylic agent, PMV5 improved inorganic property indicates the optimum impact property.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2003.02a
• /
• pp.463-469
• /
• 2003

과실은 재배기술, 재배환경의 영향으로 형상, 색택, 병충해로 인한 상해 정도가 다르게 나타나기 때문에 상품성이 매우 다양하게 결정된다. 또한 수확, 저장, 포장, 수송, 상하차 등 유통과정에서 기계적 손상이 발생할 수 있으며 유통기간이 길어짐에 따라 호흡 및 증산작용 등과 같은 생리적 작용으로 인하여 부패 및 변질이 발생하며 이러한 유통과정 중에서 발생하는 과실의 품질저하가 상당한 수준에 이르고 있으나, 이에 대한 관심은 매우 낮은 실정이다. 또한, 대부분의 청과물은 수확 후 소비되기까지 장기간의 저장으로 품질 변화가 발생할 수도 있다. (중략)

• Journal of the Korean Graphic Arts Communication Society
• /
• v.15 no.1
• /
• pp.57-69
• /
• 1997

The field of printing to use pressurized ink using screen gossamer that is called screen printing. Existing cleaning solvents for the screen printing are the organic solvents containing aromatic compounds and stench. Also, Cleaning method of screen printing are for the most part mixed cleaning method of dipping and polish. In this study, we measured the cleaning efficiency by gravimetric analysis and the property change of gossamer by image analyzer using existing cleaning solvent. Also, we investigated a new cleaning process showing excellent cleaning efficiency using the ultrasonic and vibration cleaning method instead of the exsiting mixed cleaning method.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.15 no.2
• /
• pp.1-4
• /
• 1997

Existing cleaning solvent using screen printing are the organic solvents including aromatic compounds carried with poisonous and stench. besides, Cleaning method of current screen printing are for the most part mixed cleaning method of dipping and polish. Using 1,1,1-TCE, CFC-113 alternative system cleaning solvent be substituted for existing cleaning solvent against screen printing ink measured the cleaning efficiency according to gravimetric analysis method and property change of gassamer according to Image Analyzer. Also, Cleaning process system carry with excellent cleaning efficiency studied which was proposed new cleaning process including ultrasonic cleaning process be substituted for existing mixed cleaning method of dipping and polish.

• Proceedings of the KOSOMBE Conference
• /
• v.1995 no.11
• /
• pp.177-182
• /
• 1995

Since one property(i.e. coarseness, orientation, regularity, granularity etc.) of ultrasound liver images was not sufficiently enough to classify the characteristics of livers, we used the multi-feature vectors from ultrasound images to diagnose the liver disease. The proposed classifier, which uses the multi-feature vectors and Bayes decision rule, performed well for the classification of normal, fat and cirrhosis liver. In our simulation, we used the Battacharyya distance and Hotelling Trace Criterion to select the best multi-feature vectors for the classifier and obtained less classification errors than other methods using single feature vector.