• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.140-149
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• 2006

Characteristics of a laminar diffusion flame placed near wall in microgravity have been numerically analyzed in a two-dimension. The fuel for the flame is $C_2H_4$. The flame is initiated by imposing a high temperature ignition source. The flow field, temperature field, and flame shape in microgravity diffusion flame are detailed. Especially, effects of surrounding air velocity and fuel injection velocity on the microgravity diffusion flame have been discussed accounting for standoff distance. And, the effect of curvature rate has been also studied. The results showed that velocities in a diffusion flame were overshoot because of volumetric expansion and distribution of temperature showed regularity by free-buoyancy This means that the diffusion flame in microgravity is very stable, while the flame in normal gravity is not regular and unstable due to buoyancy. Standoff distance decreases with increase in surrounding air velocity and with decrease in fuel injection velocity. With increasing curvature rate, the position of reaction rate moves away the wall.

• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.362-371
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• 2009

The key technology for developing high quality LCDs is about manufacturing BLUs with homogeneous dot distributions. Commonly, homogeneous dot distributions are obtained by the halftoning methods which convert a gray-scale image to a binary image. Among many halftoning algorithms, the error-diffusion technique based on the principle distance is known to show homogeneous dot distributions. However, this technique has a drawback; the extent of the principle distance at each pixel with respect to those of the neighboring pixels can be too small or big creating a gap or overlap. In this paper, we propose a new error diffusion algorithm based on the variable principle distance which improves the existing error diffusion technique based on the principle distance. The variable principle distance at a given pixel is calculated with gray-scale values of the pixel and its neighbors and thus the principle distance value is variable depending on the direction from that pixel. This variable principle distance technique helps BLUs obtain homogeneous dot distributions.

• Transactions of Materials Processing
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• v.30 no.5
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• pp.226-235
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• 2021

The strain aging behavior of a low carbon dual phase steel was examined in two conditions: representing room temperature strain aging (100 ℃ × 1 hr after 7.5 % prestrain) and bake hardening process (170 ℃ × 20 min after 2 % prestrain), basing on carbon effective diffusion and dislocation distribution. The first principle calculations revealed that (Mn or Cr)-vacancy-C complexes exhibit the strongest attractive interaction compared to other complexes, therefore, act as strong trapping sites for carbon. For room temperature strain aging condition, the carbon effective diffusion distance is smaller than the dislocation distance in the high dislocation density region near ferrite/martensite interfaces as well as ferrite interior considering the carbon trapping effect of the (Mn or Cr)-vacancy-C complexes, implying ineffective Cottrell atmosphere formation. Under bake hardening condition, the carbon effective diffusion distance is larger compared to the dislocation distance in both regions. Therefore, formation of the Cottrell atmosphere is relatively easy resulting in to a relatively large increase in yield strength under bake hardening condition.

• Journal of the Korean GEO-environmental Society
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• v.12 no.6
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• pp.25-34
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• 2011

Dredged and reclaimed ground in progress at the West Coast has a high content of coarse particles. There will be different behaviors depending on the location of outlet and engineering properties of soil when its ground is dredged by a pump. Therefore, the experiments were conducted that were manufactured about the chamber equipment of length 2,650mm, width 770mm, height 735mm, experimented step filling method and water content about 300%, 500% and 700% respectively with SM and ML samples in order to realize segregating sediment characteristics of dredged ground with changing much fine. With results of analysis, ML sample by higher initial water content was reached to the period of complete sedimentation and coefficient of sedimentation consolidation increased with increases of diffusion distance. SM samples showed behavior of coarse soil with diffusion distance 120cm, diffusion distance of more than 120cm showed a similar tendency with ML sample under the influence of fines. In ML sample, it could be also found that lower depth and the more increasing diffusion distance increase in percentage of sieve #200 but water content decreases. In SM sample, it could be also found that coarse soil was piled at near the diffusion distance zone but fine soil was piled at the far diffusion distance zone and prominent difference showed between percentage of sieve #200 and water content(%) by boundary point 120cm~160cm of both samples. Also, shear strength was expressed ML-maximum 2.97kPa, SM-maximum 10.2kPa with diffusion distance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.1
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• pp.1-10
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• 2001

In order to generate the gray scale image by the binary state imaging devices such as a digital printer, the gray scale image needs to be converted into the binary image by the halftoning techniques. This paper presents a new error diffusion technique to achieve the homogeneous dot distributions on the binary images. In this paper,'the minimum pixel distance'from the current pixel under binarization to the nearest minor pixel is defined first. Also, the gray levels of the input image are converted into a new variable based on the principal distance for the error diffusion. In the proposed method, the difference in the principal distances is utilized for the error propagation, whereas the gray level difference due to the binarization is diffused to the neighboring pixels in the existing error diffusion techniques. The quantization is accomplished by comparing the updated principal distance with the minimum pixel distance. In order to calculate the minimum pixel distance, MPOA(Minor Pixel Offset Array) is employed to reduce the computational loads and memory resources.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.481-489
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• 2006

Two dimensional diffusion model test was conducted to investigate the sedimentation properties and consolidation process of reclaimed ground using dredging coarse soil which is composed of passing amount 20 percentage and 45 percentage of #200 sieve size respectively. The passing amount of #200 sieve size affected on sedimentation properties. The coarse soil which is passing amount of 20 percent showed that the sedimentation structure was layered type and passing amount of 45 percentage was wall-partition type according diffusion distance. Furthermore, the water content of surface and section, and distribution of fine soil were changed according to diffusion distance. and the change amount of pore water pressure and strength property when soil is diffused, segregated and accumulated can be applied efficiently in design of dredging and reclamation.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.72-73
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• 2006

The error function can be calculated based on the Simpson method through a subroutine program. An integration program by FORTRAN language was made for diffusion equations of extended source with infinite extent and limited extent. The results on some alloying elements such as C, Co, Cr, Mn, Mo, Ni and V's diffusion in iron, showed the diffusion distance for Ni and Mo can only be $1{\sim}3\;{\mu}m$ and more distance for Co at common sintering temperature of $1120^{\circ}C$. To refine the particle size of the added elements down to a scale of micrometers is an effective way to get homogeneous distribution.

• Applied Microscopy
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• v.52
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• pp.8.1-8.7
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• 2022

The Korean trident goby, Tridentiger brevispinis, lives in adverse habitats that can easily become hypoxic due to low precipitation, regional dry periods, and high amounts of solar radiation. Histological and morphometric studies revealed the goby's specialized skin (35.4-150.0㎛ in thickness), consisting of an epidermis and dermis. The thicker epidermis comprises an outermost surface layer (having taste buds, stratified fattened cells, mucous cells, pigment cells, and stratified polygonal cells), middle layer (having stratified polygonal cells), and stratum germinativum (stratified columnar cells). In particular, the dermis has scales, well-developed vascularization, and a few blood capillaries just above the basement membrane, and a reduced diffusion distance was present in the lateral body. Consequently, adaptations such as thicker epidermis, well-developed vascularization, few blood capillaries, and a reduced diffusion distance may provide cutaneous respiration for survival in poorly oxygenated water during the periodic dry season.

• Textile Coloration and Finishing
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• v.19 no.6
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• pp.21-27
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• 2007

The factors which affect the absorption and diffusion of disperse dye in print paste for polyester film were investigated using film roll method. When Emvatex print paste of different disperse dye concentrations were fixed by high temperature steaming(HTS) for 2 hr at $190^{\circ}C$, the dye uptake and diffusion distance of 50g/kg dye concentration for PET film were very low, but those of 100$\sim$300g/kg were increased with increasing dye concentration. It was found that sodium alginate(5%) was more effective for the absorption and diffusion of disperse dye to PET film than CMC(3%) and Emvatex(18%), and Emvatex showed comparatively low absorption in three thickeners used. The dye uptake and diffusion distance of disperse dye in sodium alginate paste for PET film were increased with increasing paste thickness to $160\sim180{\mu}m$, but were decreased at $200\sim220{\mu}m$ in both fixations of baking and HTS for 2 hr at $190^{\circ}C$, and were far more largely increased by fixation of HTS than baking because steam was very important for fixation. Also it was confirmed that dye uptake was slightly increased as steam supply pressure was raised from 1 $kg/cm^2$ to 2 $kg/cm^2$, andthe dye uptake and diffusion distance of disperse dye were outstandingly increased with raising fixing temperature from $170^{\circ}C$ to $190^{\circ}C$ and fixing time from 0.5 hr to 3 hr in the fixation of HTS.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.2
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• pp.224-241
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• 2015

This study investigates the time-space characteristics of the consumptions of cultural-contents commodities and their spatial diffusion progresses via digital media. For the purpose, we examine the spatial diffusion patterns of PSY's Music Video "Gangnam Style" since it has been launched on the YouTube. By visualizing the spacio-temporal progresses of YouTube, Tweet, and Google searching data during four months after launching, we examine the time-space characteristics of diffusion patterns of the music video via each media. We found that the adapting time and the diffusion progress were not in accordance at each country. The results revel that cultural distance such as characterized by language, cultural linkage, exclusivism or courtesy for the 'Hanrue' affects quite strongly on the spatial diffusion of music video rather than physical distance.