• Korean Journal of Oriental Medicine
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• v.14 no.3
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• pp.121-126
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• 2008

Pulse diagnosis refers to the process of diagnosing a patient by feeling an artery on the wrist based on the shape that the pulse take s while the hold-down pressure increase. The styloid process artery on the wrist is usually felt, and the pulse is taken on Chon, Gwan and Cheok using three fingers. This study is to examine the structural difference in the location of pulse diagnosis by measuring and analyzing blood diameter, blood depth, and blood flow velocity of the location of pulse diagnosis by using ultrasonic wave (VOLUSION730 PRO, GE Medical, U.S.A). This study also attempted to grasp whether the characteristics of blood vessels differ depending on Body Mass Index (BMI) and analyzed their correlation with Oriental medical pulse diagnosis. The male subjects without cardiovascular diseases were divided into the normal BMI group, the underweight group and the overweight group and 10 people of each group were measured, Blood depth, blood diameter and blood flow velocity at the location of pulse diagnosis (Chon, Gwan, Cheok) of the wrists of left and right hands were measured and the pulse wave was measured by using pulse diagnosis instrument (3-D Mac, DaeyoMedi, Korea).The results of this study showed that the characteristics of blood vessels differ depending on the degrees of obesity, and the characteristics of floating pulse and sinking pulse of Oriental medical pulses were related to the degrees of obesity. This shows that the characteristics of the blood vessels of subjects and BMI information are the major indicators for diagnosis and are the matters that must always be considered when developing the algorithm of pulse diagnosis.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.1
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• pp.41-46
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• 2012

As the development of MEMS/NEMS structure and application technology the demand for an assessment of the mechanical properties have increased. The mechanical properties are mainly evaluated by using tensile test or ultrasonic wave measurement. However, the new technology have been developed such as nano-indentation, guided wave method because they have a limitation in case of a thin plate and thin film. In the study, the guided wave velocities are measured by electromagnetic-acoustic transducer(EMAT), the material properties of thin metallic foils are obtained using optimization process of the theoretical and experimental group velocity of guided wave. The Young's modulus obtained by the optimization process(201.6 GPa), nano-indentation(207.0 GPa) and literature value(203.7 GPa) of a $50{\mu}m$ thick nickel thin plate shows good agreement within 3%.

• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.117-125
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• 2009

Early in 21st century, researches about intelligent service robot that provide various services for a human out of the industrial robot only has simple pattern repetition. It concentrates in the research regarding the URC(Ubiquitous Robotic Companion) robot which connects the network in the intelligent service. This paper proposes the robot system based on network to guide a way. The robot has made by lego brick and used ultrasonic sensor, rotation sensor and RFID tag to recognize external environment. Also, it includes a PDA to process the data between robot and server. The network server transmits information to robot controller by bluetooth and it controls the course movement and evasion of the robot. In this research, the robot system based on network to guide a way is easy to expand service and is able to process a data in real time due to data processing in the server as a part of intelligent robot. And it can reduce the cost to build a robot thank to use cheaper sensor equipment.

• Composites Research
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• v.28 no.6
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• pp.348-355
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• 2015

NDT (Non Destructive Test) of the adhesive joints is very important because their strengths have greatly affected by the worker's skill and environmental condition. Recently, the electric impedance method in which 1-2 wt% CNT was dispersed in the adhesive and the electric resistance of the adhesive joint was measured was suggested for the defect detection of the adhesive joint. The uniform dispersion of CNT in the electric impedance method is very important to make a constant electric resistance of the adhesive joint and the accuracy of defect detection depends on the uniform dispersion. In this paper, the adhesive joints in which CNT was dispersed in the adhesive by the four dispersion methods were made and their electric resistance were measured. The pre-process and evaporation process of CNT using the ultrasonic method and agitation method was used and the effective dispersion method was suggested. Also, the criteria to evaluate the dispersivity was proposed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.280-280
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• 2007

Lead oxide-based ferroelectrics are the most widely used materials for piezoelectric actuators, sensors and transducers due to their excellent piezoelectric properties. Considering lead toxicity, there is great interest in developing lead-free piezoelectric materials, which are biocompatible and environmentally friendlier. Recently alkali oxide materials, including sodium - potassium niobate (NKN), have been given attention in view of their ultrasonic application and also as promising candidates for piezoelectric lead-free system. However, it is difficult to sinter such NKN-based materials via conventional sintering process. In this reason, many researchers have investigated hot press, hot isostatic press or spark-plasma sintering of NKN-based ceramics. In this study, as candidates for lead-free piezoelectric materials, dense (Na,K,Li)(Nb,Sb)$O_3$ systems were developed by conventional sintering process. The microstructures and piezoelectric properties of the (Na,K,Li)(Nb,Sb)$O_3$ systems were investigated as a function of variable compositions. The excellent piezoelectric and electromechanical properties indicate that this system is potentially good candidate as lead-free material for a wide range of electro-mechanical transducer applications.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2740-2747
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• 2024

The sintering process acquired ferromagnetic copper ferrite ceramic material with a small concentration of Ni ion at 1100 ℃ for 1 h. Previously, copper ferrite with Ni proportions powder was acquired by the wet chemical process according to the relation CuFe_2-xNi_xO₄ where x takes values 0.0, 0.015, 0.03, 0.04, and 0.05. The role of Ni ion in the copper ferrite structure was investigated by X-ray analysis, Scanning electron microscope, EDX analysis, and density measurements. The gamma-ray shielding properties for the fabricated CuFeNiO ceramics samples were evaluated using the Monte Carlo simulation method. The obtained results show an enhancement in the linear attenuation coefficient for the fabricated ceramics with increasing the insertions of Ni ions within the fabricated samples, where increasing the Ni ions concentration between 0 and 1.19 wt% increases the linear attenuation by between 1.581 and 1.771 cm^-1 (at 0.103 MeV), 0.304-0.338 cm^-1 (at 0.662 MeV), and 0.160-0.178 cm^-1 (at 2.506 MeV), respectively. Simultaneously, the radiation protection efficiency for a 1 cm thickness of the fabricated samples increased between 14.8 and 16.3% with increasing the Ni ions between 0 and 1.19 wt%. Although the Ni doping concentration does not exceed 1.5 wt% of the total composition of the fabricated ceramics, the shielding capacity of the fabricated ceramics was enhanced by more than 11%, along the studied energy interval. Therefore, the fabricated samples can be used in gamma-ray shielding applications.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.322-328
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• 2009

Emulsion polymerization of octamethylcyclotetrasiloxane (OMCTS) was conducted under ultrasonic irradiation. Two sources of ultrasound with different intensities and frequencies of 20 KHz and 40 KHz were used for horn and bath type reactor, respectively. A combined process of horn and bath was also investigated. The effectiveness of the reaction systems was investigated by measuring conversion as well as intrinsic viscosity of the products. The influence of reaction temperature and sonication time on the progress of sonochemical polymerization was examined. It was found that conversion of greater than 80% and high viscosity were achieved within a few minutes of sonication in a horn type reactor, however, conversion and viscosity showed maximum values depending upon the sonication time. In a bath type reactor where a relatively weak intensity was maintained, longer duration time of more than one hour of sonication was required to reach a high level of conversion and viscosity. Compared with the horn type system, the conversion and viscosity in the bath type reactor were increased along with the sonication time. When the polymerization was carried out in a combined system of horn and bath, the evolution of conversion and molecular weight was quite different from the other cases. For the given geometry of reaction system, acoustic analysis using a commercial software was carried out and the results were correlated with experimental observation.

• Journal of Conservation Science
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• v.28 no.3
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• pp.235-245
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• 2012

Nondestructive deterioration diagnosis has been carried out for the former ore dressing plant of the Yongwha mine in Yeongyang (Registered Cultural Property No. 255). Deterioration rates about organic contaminant and soil of the upper part (7 to 13 layer) indicate higher than the lower part (1 to 6 layer) of the ore dressing plants. By contrast, deterioration rates such as crack, break out and discoloration of the lower part indicate very higher than the upper part. It is estimated that the plants of the lower part that mechanical and chemical process had been done for flotation were damaged severely by physicochemical weathering with reaction of concrete and chemical solution. As results of ultrasonic velocity measurement, average p-wave velocity of plants were measured 2,462m/s (compressive strength $529kgf/cm^2$). As for the analytical results of surface contaminants and soil compositions using P-XRF, they were identical with major elements (Cu, Zn, Pb, Fe and As) of ore minerals from the Yongwha mine. Therefore, the ore dressing plant should be treated by phytoremediation with conservation because heavy metals could impinged upon plants and natural environment.

• Resources Recycling
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• v.30 no.6
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• pp.61-67
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• 2021

This work investigated the cementation of iridium from iridium-containing hydrochloric acid leachate. Zinc powder was used as the reducing agent, and the effects of the stoichiometric ratio of Zn/Ir, initial Ir concentration, initial pH, reaction time, and ultrasound irradiation on iridium recovery were investigated. When only the stirrer was used for cementation, the iridium recovery increased with the addition amount of zinc, and the recovery of about 70% at 40 times the stoichiometric ratio of Zn/Ir. In contrast, when employing ultrasonic irradiation with stirring, the recovery of iridium decreased at 20 times or less the stoichiometric amount of zinc. The recovery of iridium increased at 40 times the stoichiometric ratio of Zn/Ir. This result may be due to the ionization of zinc and re-dissolution of iridium during the ultrasound irradiation treatment. When a combination of ultrasonic irradiation and stirring was used for cementation, the iridium recovery increased by more than 27% compared to that when using only the stirrer. It was possible to recover 99% of iridium under the following conditions: reaction time, 60 min; initial pH, 0.01; volume of leachate, 100 mL; 1770 ppm Ir, 40 times the stoichiometric ratio of Zn/Ir.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.348-348
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• 2011

Carbon nanotube (CNT) field effect transistors and sensors use CNT as a current channel, of which the resistance varies with the gate voltage or upon molecule adsorption. Since the performance of CNT devices depends very much on the CNT/metal contact resistance, the CNT/electrode contact must be stable and the contact resistance must be small. Depending on the geometry of CNT/electrode contact, it can be categorized into the end-contact, embedded-contact (top-contact), and side-contact (bottom-contact). Because of difficulties in the sample preparation, the end-contact CNT device is seldom practiced. The embedded-contact in which CNT is embedded inside the electrode is desirable due to its rigidness and the low contact resistance. Fabrication of this structure is complicated, however, because each CNT has to be located under a high-resolution microscope and then the electrode is patterned by electron beam lithography. The side-contact is done by depositing CNT electrophoretically or by precipitating on the patterned electrode. Although this contact is fragile and the contact resistance is relatively high, the side-contact by far has been widely practiced because of its simple fabrication process. Here we introduce a simple method to embed CNT inside the electrode while taking advantage of the bottom-contact process. The idea is to utilize a eutectic material as an electrode, which melts at low temperature so that CNT is not damaged while annealing to melt the electrode to embed CNT. The lowering of CNT/Au contact resistance upon annealing at mild temperature has been reported, but the electrode in these studies did not melt and CNT laid on the surface of electrode even after annealing. In our experiment, we used a eutectic Au/Al film that melts at 250$^{\circ}C$. After depositing CNT on the electrode made of an Au/Al thin film, we annealed the sample at 250$^{\circ}C$ in air to induce eutectic melting. As a result, Au-Al alloy grains formed, under which the CNT was embedded to produce a rigid and low resistance contact. The embedded CNT contact was as strong as to tolerate the ultrasonic agitation for 90 s and the current-voltage measurement indicated that the contact resistance was lowered by a factor of 4. By performing standard fabrication process on this CNT-deposited substrate to add another pair of electrodes bridged by CNT in perpendicular direction, we could fabricate a CNT cross junction. Finally, we could conclude that the eutectic alloy electrode is valid for CNT sensors by examine the detection of Au ion which is spontaneously reduced to CNT surface. The device sustatined strong washing process and maintained its detection ability.