• Journal of Powder Materials
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• v.10 no.6
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• pp.443-447
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• 2003

Nano-sized $TiB_2$ was in situ synthesized in copper matrix through self-propagating high temperature synthesis (SHS) with high-energy ball milled Ti-B-Cu elemental mixtures as powder precursors. The size of $TiB_2$ particles in the product of SHS reaction decreases with time of preliminary mechanical treatment ranging from 1 in untreated mixture to 0.1 in mixtures milled for 3 min. Subsequent mechanical treatment of the product of SHS reaction allowed the $TiB_2$ particles to be reduced down to 30-50 nm. Microstructural change of $TiB_2$-Cu nanocomposite during spark plasma sintering (SPS) was also investigated. Under simultaneous action of pressure, temperature and electric current, titanium diboride nanoparticles distributed in copper matrix move, agglomerate and form a interpenetrating phase composite with a fine-grained skeleton.

• Journal of Powder Materials
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• v.24 no.3
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• pp.242-247
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• 2017

In this study, the electroless nickel plating method has been investigated for the coating of Ni nanoparticles onto fine Al powder as promising energetic materials. The adsorption of nickel nanoparticles onto the surface of Al powders has been studied by varying various process parameters, namely, the amounts of reducing agent, complexing agent, and pH-controller. The size of nickel nanoparticles synthesized in the process has been optimized to approximately 200 nm and they have been adsorbed on the Al powder. TGA results clearly show that the temperature at which oxidation of Al mainly occurs is lowered as the amount of Ni nanoparticles on the Al surface increases. Furthermore, the Ni-plated Al powders prepared for all conditions show improved exothermic reaction due to the self-propagating high-temperature synthesis (SHS) between Ni and Al. Therefore, Al powders fully coated by Ni nanoparticles show the highest exothermic reactivity: this demonstrates the efficiency of Ni coating in improving the energetic properties of Al powders.

• Korean Journal of Social Welfare
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• v.48
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• pp.179-213
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• 2002

The purpose of this study is to examine the effect solution-focused brief group therapy program on a relationship between developmental disorder children and their parents. The following research question is formulated to address the purpose: (1) Does solution-focused brief group therapy program will improve interaction on parents's "warmth" and "involvement"? (2) Does solution-focused brief group therapy program will improve interaction on child's overall action and relative behavior? (3) Does solution-focused brief group therapy program will improve relationship between the developmental disorder children and their parents? For research, 12 disabled children and their parents are assigned into two groups: Experimental and Control group. Findings are that. (1) The solution-focused brief group therapy program showed positive reaction on "parent's warm heart" but there was no reaction on "involvement". (2) The solution-focused brief group therapy program affect on interaction types of the disabled children. 3) According to self-recorded report, the parents' satisfaction of consultation has been increased by frequency. These results showing that the solution-focused brief group therapy are affected the interaction between developmental disorder and their own parents. Clinically, this outcome shows a significant practical implications on social work intervention.

• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.418-422
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• 2008

The preparation of FeB by SHS in $B_2O_3-Mg-Fe-Fe_3O_4$ system was investigated in this study. In the preparation of FeB, the effects of the initial pressure of inert gas in reactor, the content of Mg and $Fe_3O_4$ in mixture on the reactivity and reaction products was investigated. The minimum initial pressure of inert gas in reactor for SHS reaction in this system was 25 atm, and as the pressure increased, the concentration of unreacted Mg decreased and combustion temperature increased. At the initial inert gas pressure in reactor of 25 atm, the optimum composition for the preparation of pure FeB was $1.5B_2O_3$+3.43Mg+ 1.7Fe+$0.1Fe_3O_4$. The FeB synthesized in this condition had an irregular shape and the particle size of $5\;{\mu}m$.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.211.1-211.1
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• 2014

Recently, the scaling of conventional planar NAND flash devices is facing its limits by decreasing numbers of electron stored in the floating gate and increasing difficulties in patterning. Three-dimensional vertical NAND devices have been proposed to overcome these issues. Atomic layer deposition (ALD) is the most promising method to deposit charge trap layer of vertical NAND devices, SiN, with excellent quality due to not only its self-limiting growth characteristics but also low process temperature. ALD of silicon nitride were studied using NH3 and silicon chloride precursors, such as SiCl4[1], SiH2Cl2[2], Si2Cl6[3], and Si3Cl8. However, the reaction mechanism of ALD silicon nitride process was rarely reported. In the present study, we used density functional theory (DFT) method to calculate the reaction of silicon chloride precursors with a silicon nitride surface. DFT is a quantum mechanical modeling method to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. The bond dissociation energy of each precursor was calculated and compared with each other. The different reactivities of silicon chlorides precursors were discussed using the calculated results.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.10
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• pp.1181-1188
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• 2011

A control system for stabilizing a small robot or inverted pendulum using twisted gyro wheel is proposed. Conventional stabilizer using inertial wheel employs action-reaction force/torque to control a pendulum, which can generate relatively small torque and short period of output. In this paper, a novel actuation method using twisted gyro torque in 3-dimentional space was proposed to stabilizing a pendulum by twisting the assembly including a rotating gyro wheel. In addition, two special control functions for this type of twisted gyro wheel were designed. One is the function of self-adjusting the mass center of the robot and the other is the torque reloading configuration for continuous torque generation. The proposed system was verified by experimental result and simulation. The designed twisted gyro wheel control system can be easily packed in a small size module and installed in a humanoid robot or inverted pendulum type mechanism.

• School Mathematics
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• v.2 no.2
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• pp.475-487
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• 2000

As a result of carrying out t-test against the learning activity that used the learning materials designed by level, significant disparity was found. Thus, it was found that hte effect of this learning activity became more visible with lapse of time. But the major cause by which there appeared small significant disparity as a result of testing is that the units of experiment were limited and that the period of using the learning materials was not long. In an analysis on the results of interest test, the experimental class also appeared to show the average score that was higher than that of the comparative class by 0.10 after converting a decimal point. The outcome of attitude test was that the experimental class showed a higher average score by 0.11, as a result of converting a decimal point, than that of the comparative class. So, a large number of students showed an improved reaction. But, there seemed some problems of the learning materials or the method of progressing the activity in changing under achievement students or students who avoided studying math. When the effect of the level-based learning activity was investigated, more than 80% of the experimental class’s students showed a positive reaction. Thus, it could be judged that students, who felt some burden at studying math, might be served more largely, not by teacher’s uniform instruction, but by an individual learning using the level-based learning materials that enabled them to do a systematic self-learning for themselves.

• Korean Journal of Veterinary Service
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• v.41 no.2
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• pp.105-110
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• 2018

A total of 41 Salmonella (S.) strains were isolated from pigs suffered with severe watery diarrhea and were tried to identify by both matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and polymerase chain reaction (PCR) analysis. Fibrinous exudate and ulceration in the large intestine were prevalent in gross observation, and variable degrees of enteritis were observed in the histology of large intestines. Subsequent polymerase chain reaction (PCR) analyses demonstrated that 41 strains were identified as S. Typhimurium (39 strains), though 2 stains were failed to identify. Further identification was performed using both direct smear and protein extraction method by MALDI-TOF MS analyses. In terms of extraction methods, 100% (41/41) of isolates were identified to species level of S. spp. Whereas only 43.9% (18/41) were identified to species level using the direct method. These results thus suggest that rapid and accurate diagnosis of porcine salmonellosis can be guaranteed by MALDI-TOF MS combined with protein extraction method.

• Korean Journal of Veterinary Research
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• v.58 no.1
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• pp.27-31
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• 2018

Canine coronavirus is a single-stranded RNA virus that causes enteritis in dogs of any age. Coronaviral enteritis is seldom definitively diagnosed, since it is usually much less severe than many other types of enteritis and is self-limiting. Conventional diagnostics for the canine coronaviral enteritis such as polymerase chain reaction (PCR), virus isolation, and electron microscopic examination are inappropriate for small animal clinics due to the complicated experimental processes involved. Therefore, a commercially available lateral flow test kit based on chromatographic immunoassay techniques was tested to evaluate its performance as a first-line diagnostic test kit that could be used in clinics. The coronavirus antigen test kit detected canine coronavirus-infected dogs with 93.1% sensitivity and 97.5% specificity. The detection limit of the test kit was between $1.97{\times}10^4/mL$ and $9.85{\times}10^3/mL$ for samples with a 2-fold serial dilution from $1.25{\times}10^6\;TCID_{50}$ ($TCID_{50}$, 50% tissue culture infectious dose). Additionally, the test kit had no cross-reactivity with canine parvovirus, distemper virus, or Escherichia coli. Overall, the commercially available test kit showed good diagnostic performance in a clinical setting, with results similar to those from PCR, confirming their potential for convenient and accurate use in small animal clinics.

• Journal of Korean Physical Therapy Science
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• v.11 no.2
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• pp.46-56
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• 2004

The purpose of this study was to investigate the effect of watsu therapy on muscle tone in adult hemiparesis patient after stroke. The subject was a 66 year old patient with left hemiparesis whose self gait was independent with minimal assist. The subject was ambulatory with some degree of limitation and demonstrated a little tremor and asymmetry in the body. A multiple treatment design(A-B-C-B) for a single-subject research was used for this study. The watsu therapy consisted of basic moves, head cradle, underfar leg, near leg cradle in watsu I (transition flow), for 25 minutes, which lasted 12 sessions for a total 21 sessions. A baseline was conducted for a first time and a general ROM exercise was conducted after the first watsu therapy. Tone assessment scale was tested : 1. posturing at rest 2. response to passive movement 3. associated reaction Comparing to the baseline and general ROM exercise, The results showed that the watsu therapy had some positive effects on improvement of three tests and there was a more positive effects of both response to passive movement and associated reaction.