• Progress in Superconductivity
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• v.2 no.2
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• pp.57-64
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• 2001

We have calculated the tunneling density of states (TDOS) of a metal/d-wave superconductor proximity junction, where the metal stands fur the normal metal, 5-wave superconductor, and d-wave superconductor. The tunneling direction is through the ab-plane of the d-wave superconductor. Because of the sign change in the order parameter experienced in the multiple Andreev reflection, there appears a finite TDOS at zero bias for duty geometry, which results in the anomalous zero bias conductance peak(ZBCP). For $d_{x2-y2}$ geometry, however, no TDOS peak appears at zero bias. We have calculated TDOS for various crystal orientation of HTSC and compared with the experimental conductance.

• Progress in Superconductivity
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• v.12 no.2
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• pp.110-113
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• 2011

We have grown a Nb/Gd bilayer on a$SiO_2$/Si substrate by using a DC magnetron sputtering system, which was fabricated in situ with silicon stencil masks. In order to investigate proximity effect of the Nb/Gd bilayer, we used a planar tunnel junction with an AlOx tunnel barrier by oxidizing the Al ground electrode at the bottom. A $Co_{60}Fe_{40}$ backing of Al was deposited so as to reduce the superconductivity of the Al, ensuring a normal counterelectrode. With a 50-nm-thick Nb layer, we have measured dI/dV (dynamic conductance) by varying the thickness of Gd, which can reveal the density of states (DOS) of the Nb/Gd bilayer as a function of the Gd thickness resulting from the proximity effect of a superconductor/ferromagnet bilayer (S/F). The SF proximity effect in Nb/Gd will be discussed in comparison to our previous results of the CoFe/Nb, Ni/Nb and CuNi/Nb proximity effect; Gd is expected to show different effects since Gd has f-electrons, while CoFe, Ni, and CuNi have only d-electrons. Our studies will focus on the triplet correlation in a superconducting pair.

• Journal of the Korean Geographical Society
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• v.40 no.5 s.110
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• pp.514-532
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• 2005

The purpose of this study is to critically examine conventional spatial measures of individual accessibility, which are based on the notion of spatial proximity, the single reference location, and the unlinked travel model. Using space-time accessibility measures with the travel-activity diary data set of Portland Metro, US, three expectations from spatial measures on spatial patterns of individual accessibility were empirically examined: (1) does individual accessibility decrease with an increase of distance from the CBD?; (2) does the spatial pattern of accessibility resemble that of urban opportunity density pattern?; and (3) are spatial patterns of individual accessibility of different socio- demographic population groups basically similar as people in the same area share the same geographic characteristics regardless of gender, race, age, and so on? First of all, the results showed that spatial variations in individual accessibility were not directly determined by spatial proximity and opportunity density as suggested by previous accessibility measures. The spatial pattern of individual accessibility was dramatically different from that of urban opportunity density High peaks of accessibility level were found far away from the CBD and regional centers. This finding might be associated with the importance of multi-reference locations and linked travels in shaping accessibility in reality. Furthermore, this study found that spatial patterns of accessibility clearly differ between men and women. These findings suggest that access requires more than proximity, and that the interaction between person-specific space-time constraints and the consequential availability of urban opportunities in space-time renders different accessibility experiences to people even in the same region, which would be one of the key ingredients missing from conventional spatial measures of accessibility.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.225-226
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• 2006

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2403-2408
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• 2014

We designate multiple target areas for the advertisement disseminations in order to resolve the problem of advertisement transmission efficiency degradation due to overlapped device-to-device (D2D) transmissions and unnecessary advertisement transmissions. We here propose an efficient advertisement dissemination algorithm based on pre-selected target areas considering user density. In our proposed algorithm, relay nodes are gradually selected according to the locations of the target areas. We mathematically analyze D2D advertisement coverages of our proposed algorithm, and compare the various simulation results of the proposed algorithm with those of the conventional algorithm according to the several simulation scenarios via intensive simulations.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5229-5232
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• 2014

Background: While many studies have concluded that local traffic density is positively associated with childhood leukemia, the results are inconsistent. We therefore performed a meta-analysis to assess the relationship between traffic density and the risk of childhood leukemia. Methods: A systematic literature review was carried out using PubMed, EMBASE, and the Cochrane Library from January 1979 to December 2013. We selected and assessed journal articles evaluating the relationship between local traffic density and the risk of leukemia in children. The analysis was carried out using STATA version 12.0. Results: A total of 11 articles, including 12 estimates of effect, were included in our meta-analysis. The summary effect size from the random-effects model, expressed as an odds ratio, was 1.03 (95% CI: 0.98-1.09, p=0.002). No significant association between traffic density and the risk of childhood leukemia was found. Similar conclusions were found on subgroup analysis. Conclusions: The results of our meta-analysis suggested no association between traffic density and the risk of childhood leukemia. This implies that living in close proximity to roads with heavy traffic may not increase the risk of childhood leukemia. However, further high-quality prospective trials are needed to support these results.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.617-624
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• 1997

Over 100 experiments have been conducted at the University of Maryland to evaluate the performance of a water mist fire suppression system for protection of an interstitial space below a raised subfloor. Experiments are conducted as part of an ongoing research effort to compare the fire suppression capabilities of various water mist system designs in a raised subfloor space. Water mist system design parameters considered in the investigation include means of actuation, concentration of water mist required for extinguishment of fires, and delivery mechanisms of water mist within close proximity to the fire. Delivery of the required concentration of water mist within close proximity to the fire is a principal factor governing the adequacy of water mist systems. Two sets of experiments have been conducted to document the performance of water mist system designs. One set is involved in documenting the concentration of water mist as a function of position within the space. The second set of experiments is concerned with the ability of water mist system designs to control fires in the space. One result of the research is the assessment of the ability of a water mist system to control fires at particular locations as a function of water mist density at that location.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.921-926
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• 1997

SOI(Silicon On lnsulator) technology is many advantages in the gabrication of MOS(Metal-Oxide Semiconductor) and CMOS(Complementary MOS) structures. These include high speed, lower dynamic power consumption,greater packing density, increased radiation tolearence et al. In smiple form of bonded SOL wafer manufacturing, creation of a bonded SOI structure involves oxidizing at least one of the mirror polished silicon surfaces, cleaning the oxidized surface and the surface of the layer to which it will be bonded,bringing the two cleanded surfaces together in close physical proximity, allowing the subsequent room temperature bonding to proceed to completion, and than following this room temperature joining with some form of heat treatment step,and device wafer is thinned to the target thickness. This paper has been performed to investigate the possibility of the bonded SOI wafer manufacturing Especially, we focused on the bonding quality and thinning method. Finally,we achieved the bonded SOI wafer that Si layer thickness is below 3 .mu. m and average roughness is below 5.angs.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.15.1-15.1
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• 2009

Nano transfer printing and micro contact printing is well known printing method based on soft lithography which uses conformal soft elastomer with designed surface relief structures. Here I introduce another class of novel 3D nanofabrication technique by using the same elastomer but in a different manner. The approach, which we refer to as proximity field nanopatterning, uses the surface-reliefed elastomers as phase masks to pattern thick layers of transparent, photosensitive materials. Aspects of the optics, the materials, and the physical chemistry associated with this method are outlined. A range of 3D structures illustrate its capabilities, and several application examples demonstrate possible areas of use in technologies ranging from microfluidics to photonic materials to density gradient structures for chemical release and high-energy density science.

• Journal of Astronomy and Space Sciences
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• v.41 no.1
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• pp.35-42
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• 2024

Sungrazing comets, known for their proximity to the Sun, are traditionally classified into broad groups like Kreutz, Marsden, Kracht, Meyer, and non-group comets. While existing methods successfully categorize these groups, finer distinctions within the Kreutz subgroup remain a challenge. In this study, we introduce an automated classification technique using the densitybased spatial clustering of applications with noise (DBSCAN) algorithm to categorize sungrazing comets. Our method extends traditional classifications by finely categorizing the Kreutz subgroup into four distinct subgroups based on a comprehensive range of orbital parameters, providing critical insights into the origins and dynamics of these comets. Corroborative analyses validate the accuracy and effectiveness of our method, offering a more efficient framework for understanding the categorization of sungrazing comets.