Nano Materials and System Lab, Department of Mechanical System Engineering, School of Engineering, Jeju National University, Jeju 690-756, Korea.
Published: January 2011
AI Article Synopsis
Article Abstract
We report in this paper on the observation of temperature-dependent anisotropic transport behavior for planar-type nanostructures (in-plane and out-of-plane) fabricated on a thin graphite layer using a three-dimensional focused-ion-beam (FIB) etching technique. The transport characteristics were studied for several in-plane areas with sizes of 6 x 6 microm2, 6 x 4 microm2 and 6 x 2 microm2 planar-type structures/patterns and out-of-plane structures with the dimensions of 2 x 1 x 0.3 microm3. Both in-plane (rho(a)) and out-of-plane (rho(c)) resistivities are measured for these structures and the ratio of resistivity anisotropy is determined. The observed values of anisotropy ratio rho(c)/rho(a) were approximately 12.5 at 300 K and approximately 54 at 25 K. The room temperature value of rho(c)/rho(a) varies by a few orders from the values of previously reported anisotropy results of bulk pyrolytic graphite. However, the value of resistivity anisotropy increases with decreasing temperature, which is an identical behavior to bulk pyrolytic graphite. From current (I)-voltage (V) characteristics, we observed an ohmic behavior at 300 K for both low- and high-current biasing. This behavior turns into nonlinear characteristics when the temperature goes down. As these fabricated structures consist of multiple elementary junctions along the c-axis, nonlinear I-V characteristics result. The impurity assisted interlayer hopping conduction and thermal excitation of carriers play a key role in this effect.
Objective: Our study compared the amount of total collagen and type I collagen in ovular membranes of pregnant smokers and non-smokers.
Material And Methods: The study group consisted of 14 pregnant smokers at 24-36 weeks of gestation; 39 pregnant non-smokers between 24-36 weeks of gestation comprised the control group. The expressions of total collagen and type I collagen were analyzed using two histological sections of the fetal membranes.
Objective: To investigate the difference in corneal epithelium between patients with and without soft contact lens (SCL) wearing, and to analyze corneal epithelial changes of the eyes with long-time SCL wearing.
Methods: In this cross sectional study, the subjects were divided into two groups: 13 patients of daily SCL wearers and 11 control subjects who had never worn contact lenses. The flap of corneal epithelium was observed by transmission electron microscopy.
During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect of these measures on urban air quality, especially particle concentrations and their size distributions, atmospheric particle size distributions (0.5-20 microm) obtained using an aerodynamic particle sizer (model 3321, TSI, USA) in June 2012 were analyzed.
The adhesion characteristics of 9 clinical E.coli strains, isolated from the urine of 9 patients with spinal cord injuries in late period were evaluated. Patient age was 21 to 54 years.
Different surface densities of gold nanoparticles (AuNPs) were deposited on (3-aminopropyl)-trimethoxysilane (APTMS)-modified indium tin oxide (ITO) electrode. The electrodes were then used in poly(3-hexylthiophene): phenyl-C61-butyric-acid-methylester (P3HT:PCBM) solar cells. Enhanced photo-conversion efficiency was observed from solar cells containing adsorbed AuNPs with surface density equals to 10 +/- 3 NPs/microm2.
