Dr. Tung H. Jeong One of Five Visiting Speakers

News release announcing Dr. Tung H. Jeong, child immigrant from China and associate professor of physics at Lake Forest College, will be one of five guest speaker when the Ohio Section of the American Physical Society meets at the University of Dayton

Compact wideband patch antenna for 5 and 6 GHz WLAN applications

Copyright @ 2008 IEICEA wideband rectangular and circular mistostrip patch antenna for 5 and 6 GHz WLAN applications is presented. The rectangular and the circular patches are fed by microstrip line. All the structure is placed on the same layer with a very simple structure. The impedance bandwidth for the antenna presented 22.41 % ranging from 5.15 GHz to 6.45 GHz. The radiation pattern including E-plane and H-plane is satisfactory within this bandwidth

Fracture of a viscous liquid

When a viscous liquid hits a pool of liquid of same nature, the impact region is hollowed by the shock. Its bottom becomes extremely sharp if increasing the impact velocity, and we report that the curvature at that place increases exponentially with the flow velocity, in agreement with a theory by Jeong and Moffatt. Such a law defines a characteristic velocity for the collapse of the tip, which explains both the cusp-like shape of this region, and the instability of the cusp if increasing (slightly) the impact velocity. Then, a film of the upper phase is entrained inside the pool. We characterize the critical velocity of entrainment of this phase and compare our results with recent predictions by Eggers

Robustness of complex networks to node and cluster damage

Copyright @ 2009 Universtiy of WarwickThe goal of this investigation is to assess the robustness of two popular network structures – random networks and scale-free networks – to node and cluster damage. There is no previous work on the latter. For node damage, we remove nodes iteratively and for cluster damage, we first build a network of clusters and then remove the nodes (clusters)

Anisotropic strains and magnetoresistance of La_{0.7}Ca_{0.3}MnO_{3}

Thin films of perovskite manganite La_{0.7}Ca_{0.3}MnO_{3} were grown epitaxially on SrTiO_3(100), MgO(100) and LaAlO_3(100) substrates by the pulsed laser deposition method. Microscopic structures of these thin film samples as well as a bulk sample were fully determined by x-ray diffraction measurements. The unit cells of the three films have different shapes, i.e., contracted tetragonal, cubic, and elongated tetragonal for SrTiO_3, MgO, and LaAlO_3 cases, respectively, while the unit cell of the bulk is cubic. It is found that the samples with cubic unit cell show smaller peak magnetoresistance than the noncubic ones do. The present result demonstrates that the magnetoresistance of La_{0.7}Ca_{0.3}MnO_{3} can be controlled by lattice distortion via externally imposed strains.Comment: Revtex, 10 pages, 2 figure

Triple band double U-slots patch antenna for WiMAX mobile applications

A small triple-band 2.7 GHz, 3.2 GHz and 5.3 GHz compact microstrip patch antenna with two U-shaped slots and a small ground plane is presented. It has been developed to be used in future WiMAX technology. The required bandwidths are fulfilled the WiMAX technology 4.8 %, 3 % and 2.5 % respectively. The return loss for the triple band are -18.5 dB, -14.5 dB and -19 respectively

Facet Formation in the Negative Quenched Kardar-Parisi-Zhang Equation

The quenched Kardar-Parisi-Zhang (QKPZ) equation with negative non-linear term shows a first order pinning-depinning (PD) transition as the driving force $F$ is varied. We study the substrate-tilt dependence of the dynamic transition properties in 1+1 dimensions. At the PD transition, the pinned surfaces form a facet with a characteristic slope $s_c$ as long as the substrate-tilt $m$ is less than $s_c$. When $m<s_c$, the transition is discontinuous and the critical value of the driving force $F_c(m)$ is independent of $m$, while the transition is continuous and $F_c(m)$ increases with $m$ when $m>s_c$. We explain these features from a pinning mechanism involving a localized pinning center and the self-organized facet formation.Comment: 4 pages, source TeX file and 7 PS figures are tarred and compressed via uufile

Discussion of Revisiting the Resilience Index for Water Distribution Networks by Gimoon Jeong, Albert Wicaksono, and Doosun Kang

Cabrera Marcet, E.; Gomez Selles, E.; Del Teso-March, R.; Estruch-Juan, ME. (2019). Discussion of Revisiting the Resilience Index for Water Distribution Networks by Gimoon Jeong, Albert Wicaksono, and Doosun Kang. Journal of Water Resources Planning and Management. 145(1):1-4. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000792S14145