• 센서학회지
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• 제24권6호
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• pp.385-391
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• 2015

In this paper, we propose a new method to infiltrate $Fe_3O_4$-nanoparticles into a porous silicon film and a monitoring technique to detect packing density of nanoparticles within the film. Recently, research to use porous silicon as a drug carrier or a new functional sensor material by infiltrating $Fe_3O_4$-nanoparticles has been extensively performed. However, it is still necessary to enhance the packing density and to develop a monitoring technique to detect the packing density in real time. In this light, we forcibly injected a nanoparticle solution into a rugate-structured free-standing porous silicon (FPS) film by applying a pressure difference between the two sides of the film. We found that the packing density by the pressure-infiltration method proposed in this paper is enhanced, relative to that by the previous diffusion method. Moreover, a continuous shift in wavelength of the rugate reflectance peak measured from the film surface was observed while the nanoparticle solution was being injected. By exploiting this phenomenon, we could qualitatively monitor the packing density of $Fe_3O_4$-nanoparticles within the FPS film with the injection volume of the nanoparticle solution.

• Tribology and Lubricants
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• 제22권1호
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• pp.20-25
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• 2006

The stress behavior analysis of a-rings and packing for a LPG filling unit has been presented using a finite element analysis technique by non-linear MSC/MARC program. The sealing performance and endurance of a-rings and packing are affected by working conditions such as filling pressure, friction coefficient, compression ratio, and material properties. The elastomeric polymers of O-rings and packing are nitrile butadiene rubber (NBR) and polytetrafluoroethylene (PTFE), which are selected as proper materials of a-rings and packing based on the stress analysis results. The calculated FEM results showed that the proper material of O-ring is NBR as a secondary sealing component and the recommended material of packing is PTFE as a primary sealing unit during a LPG filling process.

• 한국세라믹학회지
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• 제31권1호
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• pp.31-38
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• 1994

To overcome the demerit of conventional forming method, new forming method, pressureless powder packing forming method, was investigated. This technique is performed by powder packing followed by the infiltration of binder solution. Various alumina powders were used as starting materials and the powders showing good packing condition through powder packing experiment were chosen. The green densities prepared by this new forming method with these powders were lower than those of specimens by pressing method, but, nearly same density was obtained in case of green body prepared with the powders having high packing density. The distribution of binder in a green body was homogeneous and it was possible to a complex shape form by this forming method.

• 대한기계학회논문집A
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• 제24권10호
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• pp.2469-2476
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• 2000

The meshing of the domain has long been the major bottleneck in performing the finite element analysis. Research efforts which are so-called meshfree methods have recently been directed towards eliminating or at least easing the requirement for meshing of the domain. In this paper, a new meshfree method for solving nonlinear boundary value problem, based on the bubble packing technique and Delaunay triangle is proposed. The method can be efficiently implemented to the problems with singularity by using formly distributed nodes.

• 디지털콘텐츠학회 논문지
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• 제15권3호
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• pp.373-380
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• 2014

악성코드는 분석가가 탐지 및 분석을 어렵게 하기 위하여 실행 압축 기술을 이용하고 있다. 최근에는 실행 압축 기술이 적용된 코드에 대응하기 위하여 실행 압축 기술에 대한 연구가 진행되고 있다. 실행 압축 기술은 압축된 실행코드를 해제해야 동작이 가능하여 실행 코드를 압축하는 과정에서 반복되는 코드를 이용한다. 따라서 일반 코드와 비교하여 반복되는 코드가 많아서 동일한 코드가 유사한 주소 값을 가지고 수행되는 특성이 있다. 코드영역을 일정한 영역으로 구분하면 실행 압축이 해제되는 코드는 원래의 코드와 비교하여 낮은 엔트로피값을 갖는다. 이를 이용하면 실행 압축 알고리즘을 알지 못한 상태에서 실행 압축 여부를 판단할 수 있으며 실행 압축코드를 해제할 수 있다. 본 논문에서는 압축이 해제되는 코드에서 명령어의 주소 값이 작은 엔트로피값을 갖는다는 것을 이용하여 실행압축을 해제하는 방법을 제안한다.

• Structural Engineering and Mechanics
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• 제15권1호
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• pp.135-149
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• 2003

The bubble packing method is implemented for adaptive mesh generation in two and three dimensions. Bubbles on the boundary of a three-dimensional domain are controlled independently of the interior bubbles in the domain, and a modified octree technique is employed to place initial bubbles in the three-dimensional zone. Numerical comparisons are made with other mesh generation techniques to demonstrate the effectiveness of the present bubble packing scheme for two- and three-dimensional domains. It is shown that this bubble packing method provides a high quality of mesh and affordable control of mesh density as well.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1135-1140
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• 2012

An electrochromatographic microchip with carboxyl-group-derivatized mono-disperse silica packing was prepared from the corresponding colloidal silica solution by utilizing capillary action and self-assembly behavior. The silica beads in water were primed by the capillary action toward the ends of cross-patterned microchannel on a cyclic olefinic copolymer (COC) substrate. Slow evaporation of water at the front of packing promoted the self-assembled packing of the beads. After thermally binding a cover plate on the chip substrate, reservoirs for sample solutions were fabricated at the ends of the microchannel. The packing at the entrances of the microchannel was silver coated to fix utilizing an electroless silver-plating technique to prevent the erosion of the packed structure caused by the sudden switching of a high voltage DC power source. The electrochromatographic behavior of the microchip was explored and compared to that of the microchip with bare silica packing in basic borate buffer. Electrophoretic migration of Rhodamine B was dominant in the microchip with the carboxyl-derivatized silica packing that resulted in a migration approximated twice as fast, while the reversible adsorption was dominant in the bare silica-packed microchip. Not only the faster migration rates of the negatively charged FITC-derivatives of amino acids but also the different migration due to the charge interaction at the packing surface were observed. The electrochromatographic characteristics were studied in detail and compared with those of the bare silica packed microchip in terms of the packing material, the separation potential, pH of the running buffer, and also the separation channel length.

• 한국항행학회논문지
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• 제16권3호
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• pp.488-494
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• 2012

본 논문은 악성코드가 사용하는 자기방어기법을 방식에 따라 분류하고, 악의적인 코드를 보호하는 방법의 일종인 패킹에 대해 소개하였으며, 패킹을 이용하는 악성코드를 보다 빠르게 분석할 수 있는 방안을 제시하였다. 패킹기법은 악의적인 코드를 은닉하고 실행 시에 복원하는 기술로서 패킹된 악성코드를 분석하기 위해서는 복원 후의 진입점을 찾는 것이 필요하다. 기존에는 진입점 수집을 위하여 악성코드의 패킹 관련 코드를 자세히 분석하여야만 했다. 그러나 본 논문에서는 이를 대신하여 악성코드를 생성한 표준 라이브러리 코드 일부를 탐색하는 방법을 제시하였다. 제시한 방안을 실제로 구현하여 보다 신속히 분석할 수 있음을 증명하였다.

• 대한두개안면성형외과학회지
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• 제9권1호
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• pp.8-11
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• 2008

Purpose: The majority of nasal bone fractures have been managed by routine procedure of closed reduction, intranasal packing or intranasal Kirschner wire (K-wire) splinting. But it leaves rooms for many complaints from patients such as pain, rhinorrhea and nasal obstructioon. Another option is, of course, no packing at all. The study was initiated to assess the necessity to pack or splint the nasal bone after routine closed reduction. Methods: We analysed the medical records of 35 patients with nasal bone fracture who were operated by closed reduction in the last 2 years. We evaluated the postoperative CT scan scores and external deviation criterias 1 month after the operation. Results: The postoperative deviation criteria and postoperative CT scan score were favorable and there were no serious complications using this technique. Conclusion: The present study demonstrates that the use of packing or splinting need not be routine in the majority of cases. The risks and discomforts associated with these procedures can often be avoided.

• 대한기계학회논문집A
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• 제25권6호
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• pp.1004-1014
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• 2001

The fully automatic algorithm from initial finite element mesh generation to remeshing in two dimensional geometry is introduced using bubble packing method (BPM) for finite element analysis. BPM determines the node placement by force-balancing configuration of bubbles and the triangular meshes are made by Delaunay triangulation with advancing front concept. In BPM, we suggest two node-search algorithms and the adaptive/recursive bubble controls to search the optimal nodal position. To use the automatically generated mesh information in FEA, the new enhanced bandwidth minimization scheme with high efficiency in CPU time is developed. In the remeshing stage, the mesh refinement is incorporated by the control of bubble size using two parameters. And Superconvergent Patch Recovery (SPR) technique is used for error estimation. To verify the capability of this algorithm, we consider two elasticity problems, one is the bending problem of short cantilever beam and the tension problem of infinite plate with hole. The numerical results indicate that the algorithm by BPM is able to refine the mesh based on a posteriori error and control the mesh size easily by two parameters.