Silicon - The TiO2/SiO2 film being the dielectric layer was grown on the n-Si wafer using radio frequency (RF) magnetron sputtering. Thus, the Au/TiO2/SiO2/n-Si metal-oxide-semiconductor (MOS)... 相似文献
Prospective fuels for a new reactor type, the so called fixed bed nuclear reactor (FBNR) are investigated with respect to reactor criticality. These are ① low enriched uranium (LEU); ② weapon grade plutonium + ThO2; ③ reactor grade plutonium + ThO2; and ④ minor actinides in the spent fuel of light water reactors (LWRs) + ThO2. Reactor grade plutonium and minor actinides are considered as highly radio-active and radio-toxic nuclear waste products so that one can expect that they will have negative fuel costs.The criticality calculations are conducted with SCALE5.1 using S8–P3 approximation in 238 neutron energy groups with 90 groups in thermal energy region. The study has shown that the reactor criticality has lower values with uranium fuel and increases passing to minor actinides, reactor grade plutonium and weapon grade plutonium.Using LEU, an enrichment grade of 9% has resulted with keff = 1.2744. Mixed fuel with weapon grade plutonium made of 20% PuO2 + 80% ThO2 yields keff = 1.2864. Whereas a mixed fuel with reactor grade plutonium made of 35% PuO2 + 65% ThO2 brings it to keff = 1.267. Even the very hazardous nuclear waste of LWRs, namely minor actinides turn out to be high quality nuclear fuel due to the excellent neutron economy of FBNR. A relatively high reactor criticality of keff = 1.2673 is achieved by 50% MAO2 + 50% ThO2.The hazardous actinide nuclear waste products can be transmuted and utilized as fuel in situ. A further output of the study is the possibility of using thorium as breeding material in combination with these new alternative fuels. 相似文献
A new high-speed low-power dual modulus prescaler (DMP) topology is proposed. In this DMP, the synchronous part is designed as a divide-by-3/4 divider using a state-selection scheme. Compared with the conventional divide-by-4/5 divider, it has a higher speed by eliminating the NAND-gate introduced critical path delay, as well as a lower power consumption by minimizing the number of full-speed D-type flip-flops (DFF's) required. Based on this topology, a divide-by-15/16 DMP is implemented in the 0.6 m standard CMOS process. Simulation result shows that a maximum operating frequency of 2.15 GHz is obtained at 3.3 V supply with a power consumption of 11.6 mW. The circuit can operate above 3 GHz with 5 V supply and down to 1.5 V supply voltage with 570 MHz input frequency. 相似文献
In design a Deuterium–Tritium (D–T) fusion driven hybrid reactor, neutronics and nuclear data libraries have an essential
role for reliable neutronics calculations. Therefore, nuclear data libraries are very important to calculate of the neutronic
parameters and selection of tritium breeder materials to be used in the blanket. In this study tritium breeding performances
of candidate tritium breeding materials, namely, Li2O, LiH, Li2TiO3, Li2ZrO3 and Li4SiO4 in a (D–T) driven fusion–fission (hybrid) reactor is investigated based on three dimensional (3-D) and one dimensional (1-D)
neutronic calculations. 3-D and 1-D neutron transport calculations are performed with Monte Carlo transport code (MCNP 4C),
SCALE 5 and ANISN nuclear data codes to determine the tritium breeding ratio (TBR) of the blanket. The effects of different
nuclear data libraries on TBR are examined and TBR calculation results are comparatively investigated. 相似文献
In this work, we report the production of NbSe2, (niobium diselenide) nanotubes by high doses of electron irradiation. The apparatus used for irradiation was a 2 MeV Van de Graaff accelerator, while the irradiation conditions were the following: voltage 1.3 MeV, current 5μA, dose rate 25 kGy/min, and total dosage 1000 kGy. Samples were analyzed with a high-resolution transmission electron microscope. The main characteristics observed were huge and very well defined nanotubes of several nm long and few nm wide, which are presumably hollow, although they are capped at one end. At this level of irradiation, we were able to find neither onion-like structure nor nanoparticles through out other areas, as it is usual in similar hexagonal structures of the dichalcogenide family. 相似文献
In this study, the electrical properties of an Al/p-Si metal/semiconductor photodiodes with Tetracyanoquinodimethane–Polyvinyl chloride (TCNQ–PVC) and PVC–TCNQ:ZnO interfacial layers were investigated. Growing of the interfacial layers on p-Si were fulfilled using electrospinning method as a fiber form. Al metallic and ohmic contacts were deposited via physical vapor deposition method. Scanning electron microscopy (SEM) pictures of the devices were captured to examine the morphology of the structure. Within the scope of electrical characterization, I–V measurements of the Al/PVC–TCNQ/p-Si and Al/PVC–TCNQ:ZnO/p-Si devices were accomplished both in the dark and under illumination conditions. Various device parameters, such as ideality factor and barrier height values were determined from I–V characteristics. Although the ideality factor values were obtained as 8.47 and 6.85 for undoped and ZnO-doped Al/PVC–TCNQ/p-Si diodes, the barrier height values were calculated as 0.84 for both devices. When a comparison was made between ZnO doped and undoped Al/PVC–TCNQ/p-Si diodes, it was evaluated that the rectification and photoresponse properties of the heterojunction diode was improved with ZnO dopant.
We report preparation of highly transparent, flexible, and thermally stable superhydrophobic organically modified silica (ORMOSIL) aerogel thin films from colloidal dispersions at ambient conditions. The prepared dispersions are suitable for large area processing with ease of coating and being directly applicable without requiring any pre- or post-treatment on a variety of surfaces including glass, wood, and plastics. ORMOSIL films exhibit and retain superhydrophobic behavior up to 500 °C and even on bent flexible substrates. The surface of the films can be converted from superhydrophobic (contact angle of 179.9°) to superhydrophilic (contact angle of <5°) by calcination at high temperatures. The wettability of the coatings can be changed by tuning the calcination temperature and duration. The prepared films also exhibit low refractive index and high porosity making them suitable as multifunctional coatings for many application fields including solar cells, flexible electronics, and lab on papers. 相似文献
In this study, failed parts from the piston engine of TB-20 Trinidad aircraft which declared an emergency landing to Anadolu University Airport, Eski?ehir, Turkey due to the overspeed of propeller during a training flight were investigated. Fortunately, landing was successful, however, most of the engine parts were found to be damaged. Some of the failed parts such as propeller governor idler gear and cam followers were examined by using a variable pressure scanning electron microscope (SEM) attached with an energy dispersive X-ray spectrometer (EDX) to identify the cause of failure in the engine. 相似文献