• Nuclear Engineering and Technology
• /
• v.54 no.1
• /
• pp.234-243
• /
• 2022

This study aims to characterize the irradiated RBMK-1500 nuclear graphite in terms of both structural and radiological properties. The experimental results of morphological and structural analysis of the irradiated graphite samples by using SEM, Raman spectroscopy as well as the theoretical evaluation of primary displacement damage are presented. Moreover, the experimental and theoretical evaluation of the neutron flux is provided and the presence of several γ emitters in the analyzed graphite samples is assessed. Furthermore, the improved version of rapid analysis method for ¹⁴C activity determination is applied and the experimentally obtained results are compared with calculated ones. Results indicate that structural changes are uniform enough in all the analyzed samples. However, the distribution of radionuclides is non-homogeneous in the irradiated RBMK-1500 reactor graphite matrix. The comprehensive understanding of both structural and radiological characteristics of nuclear graphite is very important when dealing with decision about irradiated graphite waste management strategy or treatment options prior to its final disposal.

• Animal cells and systems
• /
• v.16 no.5
• /
• pp.357-365
• /
• 2012

We have examined the effect of circadian disturbances induced by night shifts (NSs) on the phenotypes of the tibiae and abdominal adipose tissues (ADTs) in a mouse model by using in vivo micro-computed tomography (micro-CT). We found that the volumes of total and visceral ADTs in the night-shifted group of mice were significantly larger (69 and 92%, respectively) than those in the control. The mean polar moment of inertia, cross-sectional thickness, and bone mineral density of the cortical bone in the night-shifted group of mice were less (13, 5, and 3%, respectively) than those in the control. Moreover, the volume and the thickness of growth plates (GPs) of the tibiae in the night-shifted mice were significantly smaller (22 and 20%, respectively) than those in the control. Taken together, our results indicate that disturbances in the mouse circadian rhythms induced by NSs affect the morphological characteristics of cortical bone, the volume and the thickness of GPs, and the volume of ADTs.

• Applied Microscopy
• /
• v.43 no.1
• /
• pp.21-26
• /
• 2013

The oriental fruit moth (Grapholita molesta Busck) and the peach fruit moth (Carposina sasakii Matsumura) are the most severe insect pests affecting apple orchards in Korea. To prevent an outbreak of these two species and to control these agricultural insect pests, it is important to identify them accurately. However, it is hard to classify them when they were in the larval stage since they tunnel into the apple fruit. In this study, surface structures of the two species of larvae were observed using stereo microscope and scanning electron microscope. Distinct differences between the two species of larvae were found. The prothorax spiracles of oriental fruit moth larvae were approximately twice as large as those of peach fruit moth larvae. The arrangements of subventral setae, located around the proleg, were different between oriental fruit moth and peach fruit moth larvae. Furthermore, subdorsal setae of oriental fruit moth were located next to the spiracle on the 8th abdominal segment, while that of peach fruit moth was located above the spiracle. The identification of the two species of larvae observed in this study was confirmed using polymerase chain reaction-restriction fragment length polymorphism method. Surface structural differences are intrinsic characteristics for each species of larvae and can easily be identified using stereo microscope. These specificities will be helpful where a large number of field-collected larvae need to be identified routinely in pest control research.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.32 no.1
• /
• pp.35-40
• /
• 2016

Hydrogels are crosslinked hydrophilic matrices for a variety of biomedical applications. Silk fibroin (SF), one of typical natural biomaterials, has been explored as base material for hydrogel. Photocrosslinked SF hydrogel containing poly(ethylene glycol) (PEG) was formulated through visible light initiated thiol-acrylate photopolymerization. The morphological, structural and thermal properties of SF - PEG hydrogel was investigated through scanning electron microscopy, X-ray diffractometry, thermogravimetry, and differential scanning calorimetry. The morphology of SF hydrogel showed dot and uneven surface with network cross-section. X-ray diffraction curves showed that the specific diffraction peaks of PEG were not changed by the intensity of the peaks were affected by sonication. Thermo-degradation behavior of SF - PEG hydrogel sonicated was significantly affected and became complex pattern compared to unsonicated ones. However, the melting endothermic temperature of SF - PEG hydrogel was not changed but the crystalline enthalpy was decreased by gelation and sonication.

• Journal of the Semiconductor & Display Technology
• /
• v.9 no.3
• /
• pp.41-45
• /
• 2010

The ZnO thin films doped with Ga(GZO) and both Ga and Ge(GZO:Ge) were deposited on glass substrate by using RF sputtering system respectively. Structural, morphological and optical properties of the films deposited in the same condition were investigated. Structural properties of the films were investigated by Field Emission Scanning Electron Microscopy, FE-SEM images and X-ray diffraction, XRD analysis. These studies showed shape of films' surface and direction of film growth respectively. It's showed that all films were deposited by vertical orientation strongly. It can be confirmed that all dopants of targets were included in deposited films by results of EDX analysis. UV-Vis spectrometer results showed that all samples had highly transparent characteristics in visible region and have similar 3.28~3.31 eV band gap. It was found that existence of all dopants by EDX analysis. Morphology and roughness of surface of each film were clearly shown by Atomic Force Microscopy, AFM images. It was found in this research that film doped with Ge more dense and stable with hardly any difference in gap energy compared to ZnO films.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.183-184
• /
• 2006

Some researchers proposed positive effects of whole body vibration (WBV) on osteoporotic trabecular bones of animals. In the present study, the correlation between the improvement of morphological characteristics and the effect of WBV was investigated and analyzed in OVX rats. The rats were randomly assigned to 5 groups: control, sham, WBV 17Hz, WBV 30Hz and WBV 45Hz. The WBV groups were exercised on a vibration platform (magnitude : $1mm_{peak-peak}$, frequency : 17Hz, 30Hz and 45Hz, 30 minutes/day for 5 days/week). The 4th lumbar on rats was scanned by In-vivo Micro-CT at the week 0(just before WBV) and the week 8(after WBV). Structural parameters of the 4th lumbar, based on two dimensional (2D) scan image data, were investigated and analyzed. The quantitative decrement rate of trabecular bone on WBV groups with 30Hz and 45Hz were lower than control and sham groups. The results showed the positive effect of WBV on osteoporotic bones of OVX rats.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.649-650
• /
• 2006

Some researchers proposed positive effects of whole body vibration (WBV) on osteoporotic trabecular bones of animals. In the present study, the correlation between the improvement of morphological characteristics and the effect of WBV was investigated and analyzed in OVX rats. The rats were randomly assigned to 5 groups: control, sham, WBV 17Hz, WBV 30Hz and WBV 45Hz. The WBV groups were exercised on a vibration platform (magnitude $1mm_{peak-peak}$, frequency : 17Hz, 30Hz and 45Hz, 30 minutes/day for 5 days/week). The 4th lumbar on rats was scanned by In-vivo Micro-CT at the week 0(iust before WBV) and the week 8(after WBV). Structural parameters of the 4th lumbar, based on two dimensional (2D) scan image data, were investigated and analyzed. The quantitative decrement rate of trabecular bone on WBV groups with 30Hz and 45Hz were lower than control and sham groups. The results showed the positive effect of WBV on osteoporotic bones of OVX rats.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.3C no.6
• /
• pp.241-245
• /
• 2003

ZnO thin films on (l00) p-type Si and sapphire substrates have been deposited by a pulsed laser deposition technique using an Nd:YAG laser with a wavelength of 266 nm. The influence of the deposition parameters such as oxygen pressure, substrate temperature and laser energy density on the properties of the grown films was studied. The experiments were performed for substrate temperatures in the range of 200∼50$0^{\circ}C$ and oxygen pressure in the range of 100∼700 sccm. All of the films grown in this experiment show strong c-axis orientation with (002) textured ZnO peak. With increasing substrate temperature, the FWHM (full width at half maximum) and surface roughness were decreased. In the case of using sapphire substrate, the intensity of PL spectra increased with increasing ambient oxygen flow rate. We investigated the structural and morphological properties of ZnO thin films using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM).

• Journal of Korean Association for Spatial Structures
• /
• v.7 no.2 s.24
• /
• pp.45-52
• /
• 2007

The purpose of this study is to explore folding as a tool diversifying structures and shapes or forms, and to consider the role and possibilities as structural design sources. First, the morphological characteristics and the elements for transforming pattern of folding are investigated and the way of forming space is also shown. Secondly, the application methods and systems of folding are descrived.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.421.2-421.2
• /
• 2014

We report on the growth of ZnO nanorods (NRs) grown on graphite and silicon substrates via an all-solution process and characteristics of their heterojunctions. Structural investigations indicated that morphological and crystalline properties were not significantly different for the ZnO NRs on both substrates. However, optical properties from photoluminescence spectra showed that the ZnO NRs on graphite substrate contained more point defects than that on Si substrate. The ZnO NRs on both substrates showed typical rectification properties exhibiting successful diode formation. The heterojunction between the ZnO NRs and the graphite substrate showed a Schottky diode characteristic and photoresponse under ultraviolet illumination at a small reverse bias of -0.1 V. The results showed that the graphite substrate could be a good candidate for a Schottky contact electrode as well as a conducting substrate for electronic and optoelectronic applications of ZnO NRs.