• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.918-929
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• 2008

This study investigated the effects of inverted position on EEG and heart rate variability before and after Bang song gong. BSG is a training method using in qi-gong and meditation to give a convergence of consciousness on body segments in order and take a silent speech of 'song'. The subjects were the 14 university students(n=7 per group) who had not experienced any medical problem and had not practiced BSG. They took a practice of the two way of BSG training program for 30 minutes every other day for two weeks. During practicing BSG, A group took sitting position and lean sitting position by turns, B group took inverted and lean sitting position in the same way. Statistical analysis conducted by two-way ANOVA($2groups^{\ast}2periods$) with p<0.05 for average difference of EEG and HR according to position change in each group before and after BSG. In A group, EEG and HR were changeless irrespective of the change of position and BSG. On the other hand, in B group, significant changes were observed in EEG(p<0.05). ${\alpha}$ wave of inverted position were on the increase, ${\beta}$ and ${\delta}$ wave of inverted position showed smaller power after two weeks training. In the variation of HR, there were smaller variation according to the position change after BSG compared to before BSG(p<0.05). The results suggested that an inverted position may make the depth of meditation deeper, and is likely to be effective for decreasing tension of brain and the sleepiness during qi-gong training. In addition to, an inverted position seemed to promote control of blood pressure of brain. So the application of an inverted position to 'BSG' will be very helpful to achieve deeper relaxation and to obtain the desired effect from qi-gong training.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1297-1301
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• 2013

This paper analyzes of PD occurrence position through an analysis of the arrival time difference between the GIS partial discharge signal. Because of GIS (Gas Insulated Switchgear) is a facility very important power equipment and as part of the equipment that make up the power system, the stabilization of the power industry, which accounted for 88.5% share of GIS substation in the form of a substation is an important equipment for power supply. In the situation where we are gradually expanding the need for preventive diagnosis in order to improve the efficiency of equipment management and failure prevention for Preventive diagnosis. In this paper as a method for extracting pre-defect of failure of GIS Apply the average value method of calculating the 5 times each using a pulse of the first time of the second pulse (${\Delta}t$) with an oscilloscope generation position PD(Partial Discharge). the results of GIS internal inspection, the partial discharge of the actual the position of the partial discharge was confirmed with an accuracy of about 82% of positions. Arrival time difference in the most effective manner if the partial discharge of GIS internal occurs by applying the averaging method and TOA(Time of arrival) method, the partial discharge occurs you through the measurement and analysis of PD signal occurs was confirmed in the experiment are presented and diagnostic methods location tracking.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.90-97
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• 1997

Field inspections and laboratory tests for 31 agricultural reservoirs in Kyungki province were performed to provide basic data for maintenance and rehabilitation of agricultural reservoirs and to evaluate structural degradation of agricultural reservoirs Results of the study are as follows : 1) From survey's results of embankments, signs of settlement and lateral movement are appeared in 17 reservoirs. Crest settlement of 20~80cm, downstream settlement of 10~90cm, and 20~160cm lateral movement of embankments are detected from settlement and movement analysis of 17 reservoirs. Crest and downstream settlements and lateral movement are greatly occurred in 20 ~ 40 years after embankment construction. 2) About 39% of total reservoirs shows seepage problems occurred in the lower part of berm and retaining wall located between embankment and spillway. Probability of seepage problems is higher at retaining wall than others. 3) Concrete strength estimated by Schmidt hammer in structures of reservoirs is a range of 100~l50kgf/$cm^2$ and average deviation of concrete strength is about l0kgf/$cm^2$. Strength difference$({\delta}S)$ between compressive strength estimated by Schmidt hammer and uniaxial compressive strength of concrete core is about $\pm$100kgf/$cm^2$. This difference is due to absence or presence of reinforced bar in concrete core, variable length of concrete core and limitation of Schmidt hammer. 4) About 68% of total reservoirs shows leaching, 58% alkali-aggregate reaction and 71 % abrasion/frost. Leaching, alkali-aggregate reaction and abrasion/frost occurred in most reservoirs when passed 10 years after construction of structure parts.

• Journal of Powder Materials
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• v.21 no.5
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• pp.349-354
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• 2014

This study is a basic research for repair material production which manufactured a Cu repair coating layer on the base material of a Cu plate using kinetic spray process. Furthermore, the manufactured material underwent an annealing heat treatment, and the changes of microstructure and macroscopic properties in the Cu repair coating layer and base material were examined. The powder feedstocks were sphere-shaped pure Cu powders with an average size of $27.7{\mu}m$. The produced repair coating material featured $600{\mu}m$ thickness and 0.8% porosity, and it had an identical ${\alpha}$-Cu single phase as the early powder. The produced Cu repair coating material and base material displayed extremely high adhesion characteristics that produced a boundary difficult to identify. Composition analysis confirmed that the impurities in the base material and repair coating material had no significant differences. Microstructure observation after a $500^{\circ}C/1hr$. heat treatment (vacuum condition) identified recovery, recrystallization and grain growth in the repair coating material and featured a more homogeneous microstructure. The hardness difference (${\Delta}H_v$) between the repair coating material and base material significantly reduced from 87 to 34 after undergoing heat treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.1-7
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• 2011

Application of biochar to soils is proposed as a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. In addition to reducing emissions and increasing the sequestration of carbon, production of biochar and its application to soils will contribute improve soil quality and crop productivity. Objectives were i) to evaluate biochar productivity from crop residues using a low-cost field scale mobile pyrolyzer and ii) to evaluate characteristics of feedstocks and biochars from locally collected crop residues. Pyrolysis experiments were performed in a reactor operated at $400-500^{\circ}C$ for 3-4 hours using biomass samples of post-harvest residues of corn (Zea mays L.), cotton (Gossypium spp.), rice (Oryza sativa L.), sorghum (Sorghum bicolor L.) and wheat (Triticum aestivum L.). Feedstocks differed, but average conversion to biochar was 23%. Carbon content of biomass feedstock and biochar samples were 445 g $kg^{-1}$ and 597 g $kg^{-1}$, respectively. Total carbon content of biochar samples was 34% higher than its feedstock samples. Significant increases were found in P, K, Ca, Mg, and micro-nutrients contents between feedstock and biochar samples. Biochar from corn stems and rice hulls can sequester by 60% and 49% of the initial carbon input into biochar respectively when biochar is incorporated into the soils. Pyrolysis conversion of corn and rice residues sequestered significant amounts of carbon as biochar which has further environmental and production benefits when applied to soils. Field experiment with crop residue biochar will be investigated the stability of biochars to show long-term carbon sequestration and environmental influences to the cropping systems.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.482-486
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• 2005

The biodegradable poly(${\varepsilon}$-caprolactone)(PCL)/poly(ethylene imine)(PEI) microcapsules containing $Al_2O_3$ and fragrant oil were prepared with different PEI contents. The effects of stirring rate and concentration of the surfactant on the diameter and morphologies of microcapsules were investigated by using scanning electron microscope (SEM). Thermal behaviors were studied by using a differential scanning calorimetry(DSC), and the release behaviors of fragrant oil from microcapsule were characterized by UV/vis. spectrophotometer. As a result, the average particle size of the microcapsules decreased with increasing the stirring rate or concentration of the surfactant. The surface morphologies of the microcapsules were changed from smooth surfaces to skin-like rough surfaces as increasing the PEI content. These results were mainly due to the increased hydrophilic groups at the microcapsule surfaces, resulting in increasing the release rate of fragrant oil in the microcapsules studied.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.43-50
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• 2003

Today, the demand of image acquisition systems grows as the multimedia applications go on increasing greatly. Among the systems, film scanner is one of the systems, which can acquire high quality and high resolution images. However due to the nonlinear characteristic of the light source and sensor, colors of the original film image do not correspond to the colors of the scanned image. Therefore color correction mr the scanned digital image is essential in the film scanner. In this paper, polynomial regression method is applied for the color correction to CIE $L^{*}$ $a^{*}$ $b^{*}$ color model data converted from RGB color model data. A1so a film scanner hardware with 12 bit color resolution for each R, G, B and 2400 dpi was implemented by using TMS320C32 DSP chip and high resolution line sensor. An experimental result shows that the average color difference ($\Delta$ $E^{*}$$_{ab}$ ) is reduced from13.48 to 8.46.6.6.6.6.

• Journal of the Korea Computer Graphics Society
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• v.24 no.1
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• pp.27-33
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• 2018

This paper presents a new adaptive LSB steganography for high capacity in spatial color images. The number of least signi ficant bit (LSB) of each RGB component in a color image pixel, to replace with the data bits to be hidden, was determine d through analysis of the worst case peak signal noise ratio (PSNR). In addition, the combination of the number of bits is determined adaptively according to image content. That is, 70% of the data to be hidden is proposed to be replaced with 3 bit LSB of two components, 2 bit LSB of the rest component, and 30% be replaced with 4 bit LSB of each RGB compon ent. To find edge areas in an image, delta sorting in local area is also suggested. Using the proposed method, the data cap acity is 9.2 bits per pixel (bpp). The average PSNR value of the tested images with concealed data of up to 60Kbyte was 43.9 db and also natural histograms were generated.

• The korean journal of orthodontics
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• v.23 no.2 s.41
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• pp.263-273
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• 1993

The purpose of this study was to analyse the center of resistance of the maxillary first molar using the 3-dimension finite element method. An extracted maxillary first molar of normal shape and average root length was selected and sectioned every 1.5mm parallel to the cementoenamel junction. Each section was traced and digitized to construct 3-D finite element model of the maxillary first molar. After a certain magnitude of counterbalancing moment(M) was applied to the tooth, a varying single force(F) of distomesial direction was applied to a certain point of th tooth until the tooth was translated. The force producing translation(Ft) was substituted to the equation ${\Delta}d=M/Ft$ to calculate the center of resistance of the maxillary first molar. And reducing the alveolar bone level 1.68mm, and 3.36mm below to the cementoenamel junction, the tooth movement was analysed to see the effect of reducing the alveolar bone level to the location of the center of resistance. The results were as follows ; 1. The center of resistance of the maxillary first molar was 3.72mm apical, 1.10mm buccal, and 0.71mm mesial to the geometric center of the horizontally sectioned surface at the cementoenamel junction. This point was 0.36mm apical, 1.20mm buccal, and 0.71mm mesial to the trifurcation point, indicating that it was not on the tooth root. 2. As the alveolar bone level was reduced, the center of resistance of the maxillary first molar was moved to the apical direction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1535-1548
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• 2004

Condensation heat transfer experiments were conducted with the oblong shell and plate heat exchanger without oil in a refrigerant loop using R-l34a, R-407C and R-410A. An experimental refrigerant loop has been developed to measure the condensation heat transfer coefficient h$_{r}$ and frictional pressure drop $\Delta$p$_{f}$ of the various refrigerants in a vertical oblong shell and plate heat exchanger. The effects of the refrigerant mass flux(40∼80kg/$m^2$s), average heat flux(4∼8kW/$m^2$), refrigerant saturation temperature(30∼4$0^{\circ}C$) and vapor quality of refrigerants on the measured data were explored in detail. Similar to the case of a plate heat exchanger, even at a very low Reynolds number, the flow in the oblong shell and plate heat exchanger remains turbulent. A comparison of the performance of the various refrigerants revealed that R-410A had the highest heat transfer performance followed by R-l34a, and R-407C had the lowest performance of the refrigerants tested. The pressure drops were also reported in this paper. The pressure drops for R-410A were approximately 45% lower than those of R-l34a. R-407C had 30% lower pressure drops than R-l34a. Experimental results were compared with several correlations which predicted condensation heat transfer coefficients and frictional pressure drops. Comparison with the experimental data showed that the previously proposed correlations gave unsatisfactory results. Based on the present data, empirical correlations of the condensation heat transfer coefficient and the friction factor were proposed.tor were proposed.sed.