Soohwan Jang

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Bartonella species were isolated from 49% of 128 cattle from California and Oklahoma, 90% of 42 mule deer from California, and 15% of 100 elk from California and Oregon. Isolates from all 63 cattle, 14 deer, and 1 elk had the same polymerase chain reaction/restriction fragment length polymorphism profiles. Our findings indicate potential for inter- and(More)
A threshold reverse bias of ϳ21 V was observed leading to a sharp increase in the gate current of AlGaN/GaN high electron mobility transistors biased at low source-drain voltage ͑5 V͒. The gate current increases by one to two orders of magnitude at this bias, corresponding to an electric field strength around 1.8 MV cm −1. The gate current increased by(More)
AlGaN/GaN High Electron Mobility Transistors (HEMTs) with various gate lengths have been step-stressed under both on-and off-state conditions. On-state, high power stress tests were performed on 0.17 lm gate length HEMTs and a single 5 lm spaced TLM pattern. Significant degradation of the submi-cron HEMTs as compared to the excellent stability of the TLM(More)
The extraction efficiency of nonpolar a-plane (11-20) GaN LEDs on sapphire substrates has been enhanced by selectively etching the mesa sidewall faces and the n-type GaN surfaces with photoenhanced chemical wet etching. Submicron-sized trigonal prisms having prismatic planes of {1-100} were clearly displayed on the n-type GaN surfaces as well as the(More)
GaN High Electron mobility transistors (HEMTs) were electrically step-stressed under high reverse gate bias conditions. Once a threshold voltage is reached, gate current increases about two orders of magnitude. Though critical voltage was determined to be linear with increasing gate length, electrical simulations show that the maximum electric field was(More)
AlGaN/GaN High Electron Mobility Transistors were found to exhibit a negative temperature dependence of the critical voltage (V CRI) for irreversible device degradation to occur during bias-stressing. At elevated temperatures, devices exhibited similar gate leakage currents before and after biasing to V CRI , independent of both stress temperature and(More)
Large-area graphene needs to be directly synthesized on the desired substrates without using a transfer process so that it can easily be used in industrial applications. However, the development of a direct method for graphene growth on an arbitrary substrate remains challenging. Here, we demonstrate a bottom-up and transfer-free growth method for preparing(More)
We explored a liquid slip, referred to as the Navier slip, at liquid-solid interface. Such a slip is provoked by the physicochemical features of the liquid-solid system. The goal of this study was to investigate the effect of a nanoengineered surface structure on liquid slip by fabricating the self-assembly structure of nano Zinc oxide (n-ZnO). We have also(More)
To fabricate a novel microbial photobioelectrochemical cell using silicon microfabrication techniques. High-density photosynthetic cells were immobilized in a microfluidic chamber, and ultra-microelectrodes in a microtip array were inserted into the cytosolic space of the cells to directly harvest photosynthetic electrons. In this way, the microbial(More)
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