• Elastomers and Composites
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• v.54 no.1
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• pp.1-6
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• 2019

In this study, we measured the leakage current at $30{\sim}80^{\circ}C$ and $90{\sim}170^{\circ}C$ under a voltage of 200~980 V applied to samples (ordinary temperature) and polyamide film specimens degraded at $170^{\circ}C$ for 20 minute respectively. After the specimen was degraded at $130^{\circ}C$ and $50^{\circ}C$, a voltage of 200 to 800 V was applied for 10 to 60 minutes. The measurement of the leakage current resulted in the following conclusions. In the case of using Al and Cu as the main electrode, it was confirmed that the leakage current also increased in high temperatures as the voltage increased. Regardless of the type of main electrode, when the temperature was constant at $130^{\circ}C$ and $50^{\circ}C$, the leakage current increased as the voltage increased, and gradually decreased with time. As a result of the FTIR measurement, the main absorption of the infrared absorption spectrum was C=O at about $1650cm^{-1}$ and N-H diagonal vibration occurred at around $1550cm^{-1}$. There was no change in the material, so no effect of temperature was observed. By the results of SEM measurements, as the temperature of degradation increases, cracks in the specimen disappear. This may be because the amide bond (-CO-NH-) is absorbed by the material.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.4
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• pp.165-172
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• 2022

This study is conducted to verify the seismic reinforcement effects of internally inserted buckling-restrained braces supported laterally by buckling-restrained rings for the seismic reinforcement of existing reinforced concrete buildings with non-seismic details. First, to evaluate the performance of KDS, the hysteretic characteristics of buckling-restrained braces are verified, and it is discovered that they satisfy the conformance criteria of the displacement-dependent damping device. Three full-scale, two-story reinforced concrete framework specimens are prepared to verify the seismic reinforcement effects, and the proposed buckling-restrained braces are bolstered with single diagonal and V-shaped braces to be compared with non-reinforced specimens. By performing a comparison with non-reinforced specimens that present intensive shear cracks at the bottom of first-floor columns, it is revealed that the maximum load and energy dissipation of specimens reinforced with the proposed buckling restrained braces, in which the structural damage extends evenly throughout the system, are approximately 4 and 6.2 times higher, respectively, which proves the effectiveness of the proposed seismic reinforcement method.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.703-710
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• 2010

Reinforced concrete beams of existing structure often encounter insufficient shear problems for various reasons. Application of steel plates is one of widely used methods for shear strengthening of reinforced concrete beams that are insufficient of shear capacity. This study presents test results on strengthening shear deficient RC beams by external bonding of vertical and diagonal slit type steel plates with anchor bolt. Test parameters are width, interval, angle and length of slits with anchor bolt. The purpose was to evaluate the failure modes and shear capacities for RC beams strengthened by various slit type steel plates with anchor bolt. The results showed that the slit type steel plate specimens strengthened by adhesive bonding and bolting failed in shear fracture modes at maximum load. Flexural crack first occurred on the tension face of beam and then inclined cracks occurred on the shear span. Finally, slit type steel plates strengthened by adhesive bonding and fastening bolts managed to delay abrupt debonding and didn't detach fully from main body of RC beam.

• FLOWER RESEARCH JOURNAL
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• v.16 no.1
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• pp.7-11
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• 2008

In order to investigate the application of bamboo in various ways in floral designs, we analyzed 108 bamboo items from the monthly magazine 'Fleur' and from the International Flower Contest held from 2001 to 2006. We analyzed the frequency of usage of bamboos by the used parts, kind of design, type of design, and arrangement method in the design work. In terms of the used parts of the bamboo, stems took 90% of the whole work. Among the 77 designs that used stems, excluding the 20 work items presented in the International Flower Contest which has been held in April, number of the bamboo work items peaked at the beginning of the year in January and February, and during summer (July and August). Upon analyzing the type of stems that were used in the 97 works, 63% of the works used bamboo in natural state, but not processed. 48% of the works used the vertical-parallel method among the arrangement methods. Other categorized works were rounded works that were not included in the vertical, horizontal or diagonal mathod. More than 50% of the works, including the table decoration, used space decoration. Among the types of work design that used bamboo as material, 64% were decorative type, 30% graphic type, and 4% formal-linear type.

• Explosives and Blasting
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• v.28 no.1
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• pp.19-26
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• 2010

The paper presents a case study of a limestone quarry of the Philippines, where major problems in terms of improper fragmentation, poor wall control, and poor heave of the muck pile were witnessed. The paper highlights the significant role of switching over from diagonal firing pattern to V-type firing pattern, and also of making suitable adjustments in the stemming column length for improved confinement and gas retention. The study revealed that by making aforesaid design modifications in the blast round, marked improvement in blasting results was registered. Looking at the results, it was further contemplated to expand the mesh area in the subsequent blast rounds. The mesh area was incremented from the existing $8.96m^2$ to $12m^2$. The results were meticulously registered in the field, and clearly depicted definite improvements in the blast results in terms of increased P.F., reduced boulder count, reduced FEL cycle time, reduced dozing hours and improved heave.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.124-131
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• 2014

In this paper, we propose the non-contact gesture recognition algorithm using 4- channel electrometer sensor array. ELF(Extremely Low Frequency) EMI and PLN are minimized because ambient electromagnetic noise around sensors has a significant impact on entire data in indoor environments. In this study, we transform AC-type data into DC-type data by applying a 10Hz LPF as well as a maximum buffer value extracting algorithm considering H/W sampling rate. In addition, we minimize the noise with the Kalman filter and extract 2-dimensional movement information by taking difference value between two cross-diagonal deployed sensors. We implemented the DTW gesture recognition algorithm using extracted data and the time delayed information of peak values. Our experiment results show that average correct classification rate is over 95% on five-gesture scenario.

• Journal of the Korean Chemical Society
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• v.19 no.2
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• pp.85-91
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• 1975

The crystal structure of piperidinothiosemicarbazide, $C_6H_{13}N_3S$, has been determined by single crystal X-ray analysis. The space group is P21/c with four molecules in the unit cell of dimensions $a=14.68{\pm}0.04,\;b=4.59{\pm}0.02,\;c=12.92{\pm}0.04{\AA}\;and\;{\beta}=109.4{\pm}0.2^{\circ}$. Three-dimensional photographic intensities were estimated visually. The structure has been solved by an interpretation of a Patterson synthesis and refined by block-diagonal least-squares methods to give a final R value of 0.14 for 378 observed independent reflections. There are two independent hydrogen bonds in the structure. One of them is of the type N-H${\ldots}$S with the length 3.28 and $3.39{\AA}$, and another is of the type N-H${\ldots}$N with the length $3.03{\AA}$. Apart from the hydrogen bonding system the molecules are held together in the crystal by van der Waals forces.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.57-61
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• 1999

In the field of image compression, Classified Vector Quantization(CVQ) reveals attractive characteristics for preserving perceptual features, such as edges. However, the classification scheme is not generalized to effectively reconstruct different kinds of edge patterns in the original CVQ that predefines several linear-type edge classes: vortical edge horizontal edge diagonal edge classes. In this paper, we propose a new classification scheme, especially for edge blocks based on the similarity measure for edge patterns. An edge block is transformed to a feature vector that describes the detailed shape of the edge pattern The classes for edges are formulated automatically from the training images to result in the generalization of various shapes of edge patterns. The experimental results show the generated linear/nonlinear types of edge classes. The integrity of all the edges is faithfully preserved in the reconstructed image based on the various type of edge codebooks generated at 0.6875bpp.

• Journal of the Korean Chemical Society
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• v.21 no.5
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• pp.320-329
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• 1977

p-Phenylenediamine dihydroperchlorate, $C_6H_4N_2H_4{\cdot}2HC1O_4$, crystallizes in space group $P\={1}$ with $a=4.79{\pm}0.02,\;b=9.03{\pm}0.02,\;c=7.12{\pm}0.03{\AA},\;{\alpha}=109.4{\pm}0.2,\;{\beta}=79.6{\pm}0.2,\;r=104.6{\pm}0.2^{\circ},\;Z=1$. The structure has been solved by the Patterson and Fourier methods. The refinement by block-diagonal least-squares cycles gives R = 0.13 for 387 observed reflexions collected on equi-inclination Weissenberg photographs with CuK${\alpha}$ radiation. There are two different types of five hydrogen bonds. The first type consists of one trifurcated N${\cdot}{\cdot}{\cdot}$O hydrogen bond and the second of two normal N${\cdot}{\cdot}{\cdot}$O hydrogen bonds, both of which exist between the amino group and the perchlorate, groups. A p-phenylenediamine group is approximately planar within an experimental error and bonded to twelve perchlorates: ten perchlorates forming hydrogen bonds and two being contacted with the van der Waals forces. A perchlorate group is surrounded by six p-phenylenediamines and four perchlorates; among the six p-phenylenediamines, five of them are hydrogen-bonded, and the rest contacted with the van der Waals force.ce anaysis of our samples and investigated the variarions in the values of parameters obtained through fitting the theoretical impedance to the experimental impedance. The characters of the dielectric constant and the impedance showed abnormal variations for the 0.2 at K-doped NSBN ceramics, which we were able to interpret in terms of the variations in the number A-site vacancies with the K doping ratio. From these results, A-site vacancies are thought to be space charges that influence the ferroelectric properties of NSBN ceramics.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.5 s.305
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• pp.95-102
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• 2005

When images compressed with block-based compression techniques are transmitted over a noisy channel, unexpected block losses occur. In this paper, we present a post-processing-based block recovery scheme using Haar wavelet features. No consideration of the edge-direction, when recover the lost blocks, can cause block-blurring effects. The proposed directional recovery method in this paper is effective for the strong edge because exploit the varying neighboring blocks adaptively according to the edges and the directional information in the image. First, the adaptive selection of neighbor blocks is performed based on the energy of wavelet subbands (EWS) and difference of DC values (DDC). The lost blocks are recovered by the linear interpolation in the spatial domain using selected blocks. The method using only EWS performs well for horizontal and vertical edges, but not as well for diagonal edges. Conversely, only using DDC performs well diagonal edges with the exception of line- or roof-type edge profiles. Therefore, we combined EWS and DDC for better results. The proposed methods out performed the previous methods using fixed blocks.