• 대한기계학회논문집
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• 제18권3호
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• pp.635-644
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• 1994

This study investigated mainly on the flow characteristics of a droplet in the cross region of twin spray. The velocities of the droplet were measured along the axial and radial direction, and the flow characteristics of the droplet were statistically analyzed. For the statistical analysis, the probability density of the turbulent components has been studied, and then the Reynolds shear stress, the skewness and the flatness factors were calculated, and compared with the Gaussian value. Two pressure swirl stomizers were used for the twin spray system and kerosene was employed as the working liquid. 2-D PDA(particle dynamic analyzer) was used for the purpose of the measurement of droplet size and velocities. As a result, it was found that (1) the droplets collision was taken place strongly in the cross region. So, a large momentum loss of droplets due to the loss of natural movement direction was occurred, and momentum loss of radial direction was greater than that of axial direction. (2) The axial direction skewness factor approached to zero like the Gaussian distribution in the cross region of twin spray. (3) In the cross region of twin spray, the fluctuation instability of droplet was increased because of the development of the turbulence characteristics due to the droplet collision.

• 펄프종이기술
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• 제47권6호
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• pp.49-56
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• 2015

To investigate fiber orientation of Korean traditional paper, Hanji, the fiber arrangements on the surface and cross section of Hanji were observed by scanning electron microscope (SEM). The surface observation showed that the fibers of traditional paper were arranged in vertical and horizontal directions, and those of ssangbal sheet forming were arranged more in vertical direction. The fibers of machine made Hanji and copying paper were usually arranged in vertical direction. As for the observation of cross section of traditional paper, fibers arranged in horizontal direction tended to be increased with the increase of thicknesses. The thick traditional paper have cracks in the middle part of structural section of paper. They were larger in cross section in horizontal direction than in vertical direction. The horizontal arrangement of traditional paper seemed to be about 8% to 14% higher to the vertical arrangement, which is very lower to other papers.

• 한국표면공학회지
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• 제29권5호
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• pp.399-406
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• 1996

The orientational cross-over phenomena in an RF sputtering growth of TiN films were studied in an in-situ, real-time synchrotron x-ray scattering experiment. For the films grown with pure Ar sputtering gas, the cross-over from the more strained (002)-oriented grains to the less strained (111)-oriented grains occurred as the film thickness was increased. As the sputtering power was increased, the cross-over thickness, at which the growth orientation changes from the <002> to the <111> direction, was decreased. The addition of $N_2$ besides Ar as sputtering gas suppressed the cross-over, and consequently resulted in the (002) preferred orientation without exhibiting the cross-over. We attribute the observed cross-over phenomena to the competition between the surface and the strain energy. The x-ray powder diffraction, the x-ray reflectivity, and the ex-situ AFM surface topology study consistently suggest that the microscopic growth front was in fact always the (002) planes. In the initial stage of growth, the (002) planes were aligned to the substrate surface to minimize the surface energy. At later stages, however, the (002) growth front tilted away from the surface by about $60^{\circ}$ to relax the strain, which caused the cross-over of the preferred growth direction to the <111> direction.

• 한국포장학회지
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• 제7권1호
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• pp.9-15
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• 2001

Top-to-bottom compression strength of corrugated fiberboard boxes is partly dependent on the load-carrying ability of the central panel areas. The ability of these central areas to resist bending under load will increase the stacking strength of the box. The difference of box compression strengths, among boxes which are made with identical dimensions and fabricated with same components but different flute sizes, is primarily due to difference of the flexural stiffness of the box panels. Top-to-bottom compression strength of a box is accurately predicted by flexural stiffness measurements and the edge crush test of the combined boards. This study was carried out to analyze the flexural stiffness, maximum bending force and maximum deflection for various corrugated fiberboards by experimental investigation. There were significant differences between the machine direction (MD) and the cross-machine direction (CD) of corrugated fiberboards tested. It was about 50% in SW and DW, and $62%{\sim}74%$ in dual-medium corrugated fiberboards(e.g. DM, DMA and DMB), respectively. There were no significant differences of maximum deflection in machine direction among the tested fiberboards but, in cross direction, DM showed the highest value and followed by SW, DMA, DMB and DW in order. For the corrugated fiberboards tested, flexural stiffness in machine direction is about $29%{\sim}48%$ larger than cross direction, and difference of flexural stiffness between the two direction is the lowest in DMA and DMB.

• 비교문화연구
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• 제39권
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• pp.177-190
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• 2015

This study investigates the difference of the cognitive approach of Korean and Chines of the space direction that modern Chinese space phrase 'N+shang'. For this, we defined the spatial meaning of the noun 'N' and space noun 'shang' then investigate the conditions when 'N+shang' means 'the substance interior direction' and 'the substance exterior direction'. Also via 'lou+shang', we conducted the survey to Korean and Chinese students in order to see the what kind of cognitive differences be shown when they approach and translate the space direction of 'N+shang' structure. As a result of the survey, we were able to find cultural difference of spatial approach of 'N+shang' between these two countries, Korean select the cognitive inference path; from the substance external direction to internal direction while Chinese select from internal to external.

• Journal of the Korean Wood Science and Technology
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• 제51권4호
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• pp.239-252
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• 2023

In this study, bending and compression strength tests were performed to investigate effect of composition of layer layout of Larix cross-laminated timber (CLT) on mechanical properties. The Larix CLT consists of five laminae, and specimens were classified into four types according to grade and composition of layer. The layer's layout were composited as follows 1) cross-laminating layers in major and minor direction (Type A), and 2) cross-laminating external layer in major direction and internal layer applied grade of layer in minor direction (Type B). E12 and E16 were used as grades of lamina for major direction layer of Type A and external layer of Type B according to KS F 3020. In results of the bending test of CLT using same grade layer according to layer composition, the modulus of elasticity (MOE) of Type B was higher than Type A. In case of prediction of bending MOE of Larix CLT, the experimental MOE was higher than 1.00 to 1.09 times for Shear analogy method and 1.14 to 1.25 times for Gamma method. Therefore, it is recommended to predict the bending MOE for Larix CLT by shear analogy method. Compression strength of CLT in accordance with layer composition was measured to be 2% and 9% higher for Type A using E12 and E16 layers than Type B, respectively. In failure mode of Type A, progress direction of failure generated under compression load was confirmed to transfer from major layer to minor layer by rolling shear or bonding line failure due to the middle lamina in major direction.

• 펄프종이기술
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• 제31권5호
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• pp.73-85
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• 1999

Yield and fracture are separated in the tensile failure of paper. Failure in the machine direction of photocopy paper is contrasted with failure in the cross-machine direction . The ratios of distortion (shape change) to dilatation (volume change) for individual elements at yield and fracture are described. The ratios of distortion to dilatation are measured and compared to predicted values of the strain energy density theory. To evaluate the effect of the angle from the principal material direction on the strain energy density theory. To evaluate the effect of the angle from the principal material direction on the strain energy density factor, samples are prepared from machine direction to cross-machine direction in 15 degree intervals. the strain energy density of individual elements are obtained by the integration of stress from finite element analysis with elastic plus plastic strain energy density theory. Poison's ratio and the angle from the principal material direction have a great effect ion the ratio fo distortion to dilatation in paper. During the yield condition, distortion prevails over dilatation . At fracture, dilatation is at a maximum.

• 한국정보통신학회논문지
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• 제13권8호
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• pp.1527-1533
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• 2009

본 논문에서는 MVP 분포의 움직임 방향 치우침 특성을 이용한 방향성 탐색 패턴을 디자인하고, 탐색점의 이동 방향에 따라 탐색 패턴을 적응적으로 변화시키는 방향 적응적 십자형 다이아몬드 탐색 방법을 제안 한다. 제안한 방법은 이웃 매크로 블록으로부터 모션 벡터를 예측하고, 예측한 모션 벡터를 이용하여 초기 움직임 방향을 설정 한다. 탐색 과정에서 BMP의 이동 방향에 따라 제안한 탐색 패턴을 적응적으로 변화시킴으로써 탐색 효율을 향상시킨다. 실험 결과, 제안한 방법 은 움직임 추정에 소요되는 계산량을 기존의 십자형 다이아몬드 탐색에 비해 $0.43%{\sim}1.76%$ 감소시킴으로써 고속 움직임 추정이 가능함을 알 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.218-223
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• 2011

Seated human subjects have been exposed to vertical vibration so as to investigate six-axis biodynamic response. Sixteen males were exposed to random vertical vibration in the frequency range(3~40Hz) at one vibration magnitude(0.224m/$s^2$ r.m.s.). Forces were measured in the vertical, fore-and-aft, lateral, roll, pitch and yaw direction on the seat. The median of cross-axis apparent mass magnitude in the fore-and-aft direction could reach up to 20% of the apparent mass magnitude at resonance frequency. And the median of apparent eccentric mass magnitude in the roll direction could reach up to 15% of the apparent eccentric mass magnitude in the pitch direction at resonance frequency. But cross-axis apparent mass in the lateral direction and apparent eccentric mass in the yaw direction showed very small.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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• pp.689-702
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• 2017

In this study, with the view to using effectively small and medium diameter Korean domestic woods as structural materials, cross-laminated woods were manufactured by using six species of Korean domestic softwoods and hardwoods, and bending creep properties were investigated for each species. The creep curves showed the shape of the exponential function plot, and the creep curves after 1 hour were able to estimate by fitting it to the power law. The initial and creep compliances of cross-laminated woods showed the higher values in wood species with a low density than in that with a high density. And by cross-laminating, the initial and creep compliances perpendicular to the grain considerably decreased, the extent of the decrease was found to be greater in creep deformation than in initial deformation. The creep anisotropies of cross-laminated woods were considerably decreased by cross-laminating. The relative creep of $C_{\bot}$ type composed of perpendicular-direction lamina in the faces decreased 0.59 - 0.64 times compared to that of $P_{\bot}$ type composed of perpendicular-direction laminae in all layers, and that for $C_{\parallel}$ type composed of parallel-direction laminae in the faces increased 1.5 - 1.6 times compared to that of $P_{\parallel}$ type composed of parallel-direction laminae in all layers.