3,582 research outputs found
Unsteady flow analysis of combustion processes in a Davis gun
No full textThe Davis gun, a type of recoilless gun, has the advantages of requiring less rear area and less powder than a conventional recoilless gun. The unsteady pressure and flow fields of a Davis gun were numerically simulated by using a two-phase fluid dynamic model. Numerical simulation results were compared with experimental values to evaluate the feasibility of the interior ballistic model. The interior ballistics in a Davis gun with a simple countermass were predicted with the computational model. It was shown that the pressure-time curves matched well between experimental data and numerical analysis except in the vicinity of the peak pressure and steep pressure gradient. The predicted muzzle velocity of projectile and countermass was closely similar to the experimental one. In this study, large pressure waves were not observed since the initial porosity was relatively high (phi(0) = 0.867) and the charge was ignited at the centre of the granular bed
Person Wide Web: Active Location based Web Service Architecture using Wireless Infrastructure
No full textThis research is supported by the Ubiquitous Computing and
Network (UCN) project, Knowledge and Economy Frontier
R&D Program of the Ministry of Knowledge Economy (MKE)
in Korea as a result of UCN’s subproject 10C1-T1-20S. And,
we are thankful to Sang-Ok Cho, research staff at Octacomm
Inc. (http://octacomm.net) for his support to our research
In Vitro Cell Traction Measurement Platform for Analyzing Cell Heterogeneity in Skeletal Muscle Differentiation
No full textUnequal activation volumes of well-motion and nucleation process in Co/Pt multilayers
No full textMagnetic field dependence of magnetization reversal in ColPt multilayers was qmmtitatively investigated. Serial
samples of ColPt multilayers were prepared by dc-magnetron sputtering under various Ar pressures. Magnetization
reversal was monitored by magnetization viscosity measurement and direct domain observation using a
magneto-optical microscope system, and the wall-motion speed V and the nucIeation rate R were determined
using a domain reversal model based on time-resolved domain reversal pattems. Both V and R were found to be
exponentially dependent on the applied reversing field. From the exponential dependencies, the activation volumes
for wall motion and nucIeation could be determined, based on a thermally activated relaxation model, and
the wall-motion activation volume was found to be slightIy larger than the nucIeation activation volume.This work was supported by the Korean Ministry of Science and Technology through the Creative Research Initiatives
Program
AIM817986_Supplemental_material_SP1 – Supplemental material for Cervical surgery rate in neck pain patients with and without acupuncture treatment: a retrospective cohort study
No full textSupplemental material, AIM817986_Supplemental_material_SP1 for Cervical surgery rate in neck pain patients with and without acupuncture treatment: a retrospective cohort study by Dong-geun Han, Wonil Koh, Joon-Shik Shin, Jinho Lee, Yoon Jae Lee, Me-riong Kim, Kyungwon Kang, Byung-Cheul Shin, Jae-Heung Cho, Nam-Kwen Kim and In-Hyuk Ha in Acupuncture in Medicine</p
Comparative analysis of the transcriptome of injured nerve segments reveals spatiotemporal responses to neural damage in mice
No full textNerves are particularly vulnerable to damage due to their unique structure with meter-long axons. In the peripheral nervous system neurons and Schwann cells can activate the injury-response program that directs axons to either regenerate or degenerate after traumatic nerve injury. However, the differences between the genetic programs driving nerve regeneration and degeneration have not yet been described extensively. To understand these differences, in this study we have compared the injury-induced transcriptomic changes between the regenerating proximal segment and the degenerating distal segment of a transected nerve, at different post-injury time points. We analyzed the spatiotemporal dynamics of the mouse transcriptome using a sciatic nerve-injury model by means of RNA sequencing. The results of the differentially regulated genes (DEGs) analysis show that some DEG groups are similarly regulated in both proximal and distal segments, and primarily display a positive correlation. However, some DEG groups are exclusively regulated in either the proximal or the distal segment, suggesting that these DEG groups constitute a genetic network for distinguishing the regenerative and degenerative responses. In addition, our gene ontology analysis revealed an enrichment of particular biological processes in different phases and locations. Thus, our data provide a spatiotemporal profile of the transcriptomes that are differentially regulated in either regenerating or degenerating nerves, in vivo. The specific biological processes enriched in the DEG groups might delineate the injury-responsive program that induces contrasting regenerative and degenerative responses in different nerve segments.
Study on magnetic·magnetoopitc properties and magnetization reversal in Co/Pt multilayers
No full text학위논문(석사) - 한국과학기술원 : 물리학과, 2000.2, [ iii, 46 p. ]한국과학기술원 : 물리학과
Study on magnetization reversal in Co-based multilayer thin films and wires
No full text학위논문(박사) - 한국과학기술원 : 물리학과, 2005.2, [ vii, 57 p. ]나노자성박막과 나노자성구조에서의 자구 형상과 동역학에 관한 연구는 자구생성, 자화역전 등과 같은 기본적인 자기 특성을 이해하기 위해서 뿐 만 아니라, 기술적인 면에 있어서도 초고밀도 자기기록 및 스핀트로닉스의 응용에서 매우 중요한 분야이다. 본 연구에서는 Co계 다층박막과 와이어에서의 자화역전과 자구 동역학에 관하여 연구하였다. 자구의 형상과 동역학을 연구하기 위해서 고성능 광자기현미경자력계(MOMM)을 이용하였다. 이 장비는 편광 현미경과 디지털 증폭 CCD, 그리고 고속 영상캡쳐장비로 구성이 되어있으며, MOKE 현상을 이용하여 자구를 실시간으로 직접 관찰하고 저장할 수 있다. 각기 다른 Ar 가스 압력에서 dc 마그네트론 스퍼터링 방법으로 제작된 동일한 조성의 Co/Pt 다층박막을 광자기현미경자력계를 이용하여 자화역전 및 자구 동역학을 실험하였다. 시간에 따른 자구이미지들을 정량적으로 분석하여, wall-motion 활성화 부피와 nucleation 활성화부피를 각각 구하였다. Nucleation 과정이 우세한 자화반전 형태를 보이는 모든 시료에 대해서 wall-motion 활성화 부피가 nucleation 활성화부피보다 큰 사실을 발견하였다. 자구반전에한국과학기술원 : 물리학과
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