Publications by authors named "Doyoung Jang"

A sparse array offers a significant reduction in the complexity of ultrasonic imaging systems by decreasing the number of active elements and associated electrical circuits needed to form a focused beam. Consequently, for 1-D arrays, it has been adopted in the development of miniaturized systems such as portable, handheld, or smartphone-based systems. Previously, we developed an analytic method that can design a pair of 1-D periodic sparse arrays (PSAs) satisfying three specific constraints, which are the array size, desired grating lobe level, and sparseness factor (SF).

View Article and Find Full Text PDF

Due to bandgap tunability, GaAsSb nanowires (NWs) have received a great deal of attention for a variety of optoelectronic device applications. However, electrical and optical properties of GaAsSb are strongly affected by Sb-related defects and scattering from surface states and/or defects, which can limit the performance of GaAsSb NW devices. Thus, in order to utilize the GaAsSb NWs for high performance electronic and optoelectronic devices, it is required to study the material and interface properties (e.

View Article and Find Full Text PDF

We developed a nanoneedle transistor-based sensor (NTS) for the selective detection of calcium ions inside a living cell. In this work, a single-walled carbon nanotube-based field effect transistor (swCNT-FET) was first fabricated at the end of a glass nanopipette and functionalized with Fluo-4-AM probe dye. The selective binding of calcium ions onto the dye molecules altered the charge state of the dye molecules, resulting in the change of the source-drain current of the swCNT-FET as well as the fluorescence intensity from the dye.

View Article and Find Full Text PDF

Low-frequency noise of individual MWNTs was investigated with different metal electrodes. Irrespective of the ohmic or non-ohmic voltage-current characteristics, a strong dependence of the noise on the metal contacts was observed. The good electrical contacts with Pd or Pt electrodes enable a quasi-ballistic transport with a bigger exponent in the relation of S1 alpha R4.

View Article and Find Full Text PDF

A simple maskless photolithography system employing an optical microscope, a motorized stage and a beam blanker is proposed. Based on a pattern design, the motorized stage shifts a resist-coated substrate exposed by a focused beam under a microscope. Microscale patterns are easily defined on a single nanowire without using a mask validating the application applying to the research requiring frequent changes or free-style designs in microscale test patterns.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_session7cnte24q0fd8np1qlf688u5iq0sbs4e9): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once