Abstract Hexagonal YMnO3 thin films were prepared on Pt(111)/TiOx/SiO2/Si and Pt(111)/Al2O3(0001) substrates using alkoxy-derived precursor solutions. The films were prepared by spin coating the YMnO3 precursor solutions and then, the films were calcined and crystallized via rapid thermal annealing in oxygen or vacuum ambient. The annealing conditions and substrates were critical for crystallization of ferroelectric YMnO3 films. When annealed in vacuum, the films both on Pt(111)/TiOx/SiO2/Si and Pt(111)/Al2O3(0001) substrates crystallized to hexagonal YMnO3 and the orientation depended on the substrates. The film on Pt(111)/Al2O3(0001) had c-axis orientation and the film on Pt(111)/TiOx/SiO2/Si had no preferred orientation. In addition, it was found that crystallization behavior, orientation and morphology of YMnO3 films on Pt(111)/TiOx/SiO2/Si substrates depended on the annealing condition. The heat-treatment in vacuum at initial stage for crystallization affected the restraint of perovskite phase and formation of hexagonal phase. The following heat-treatment in oxygen promoted the c-axis orientation and grain growth. The optimum annealing procedure for crystallization of the c-axis oriented YMnO3 films on Pt(111)/TiOx/SiO2/Si was addressed. 相似文献
Load-leveling hyper energy converting and utilization system (LHECUS) is a hybrid cycle which utilizes ammonia–water mixture as the working fluid in a combined power generation and refrigeration cycle. The power generation cycle functions as a Kalina cycle and an absorption refrigeration cycle is combined with it as a bottoming cycle. LHECUS is designed to utilize the waste heat from industry to produce cooling and power simultaneously. The refrigeration effect can be either transported to end-use sectors by means of a solution transportation absorption chiller (STA) as solution concentration difference or stored for demand load leveling. 相似文献
4S reactor is a sodium-cooled fast reactor developed as a small-decentralized power supply. The name of “4S” in this reactor stands for Super-Safe, Small and Simple, and they show representative features of the reactor.
The purpose of the present work is to evaluate quantitatively the super-safety of 4S reactor, and the safety performance is analyzed with ARGO-3, which is a plant dynamics code of a sodium-cooled fast reactor.
In this evaluation, some events, such as Unprotected Loss of Flow (ULOF) and Unprotected Transient Overpower (UTOP), are selected as typical cases from various transients and accidents. After metrics concerned with safety design is defined for each event, it is evaluated with statistical methods whether each metric satisfies acceptance criteria in a given criteria level.
Result about ULOF is as follows. The coolant temperature in the nominal hottest assembly outlet, “Tc” is selected as metric, and the upper side value of 95% confidential section in Tc is below 900 °C that is acceptance criteria. Also in UTOP, it is shown that the fuel maximum temperature in the nominal hottest assembly, “Tf” satisfies acceptance criteria. This result shows that 4S reactor has margin for safety acceptance criteria. 相似文献
The objective of this study is to propose and evaluate advanced absorption cycles for the coefficient of performance (COP) improvement and temperature lift enhancement applications. The characteristics of each cycle are assessed from the viewpoints of the ideal cycle COP and its applications. The advanced cycles for the COP improvement are categorized according to their heat recovery method: condensation heat recovery, absorption heat recovery, and condensation/absorption heat recovery. In H2O–LiBr systems, the number of effects and the number of stages can be improved by adding a third or a fourth component to the solution pairs. The performance of NH3–H2O systems can be improved by internal heat recovery due to their thermal characteristics such as temperature gliding. NH3–H2O cycles can be combined with adsorption cycles and power generation cycles for waste heat utilization, performance improvement, panel heating and low temperature applications. The H2O–LiBr cycle is better from the high COP viewpoints for the evaporation temperature over 0°C while the NH3–H2O cycle is better from the viewpoint of low temperature applications. This study suggests that the cycle performance would be significantly improved by combining the advanced H2O–LiBr and NH3–H2O cycles. 相似文献
The objectives of this paper are to analyze a combined heat and mass transfer for an ammonia–water absorption process, and to carry out the parametric analysis to evaluate the effects of important variables such as heat and mass transfer areas on the absorption rate for two different absorption modes — falling film and bubble modes. A plate heat exchanger with an offset strip fin (OSF) in the coolant side was used to design the falling film and the bubble absorber. It was found that the local absorption rate of the bubble mode was always higher than that of the falling film model leading to about 48.7% smaller size of the heat exchanger than the falling film mode. For the falling film absorption mode, mass transfer resistance was dominant in the liquid flow while both heat and mass transfer resistances were considerable in the vapor flow. For the bubble absorption mode, mass transfer resistance was dominant in the liquid flow while heat transfer resistance was dominant in the vapor region. Heat transfer coefficients had a more significant effect on the heat exchanger size (absorption rate) in the falling film mode than in the bubble mode, while mass transfer coefficients had a more significant effect in the bubble mode than in the falling film mode. 相似文献
Micron-scale monodisperse oil-in-water (O/W) micropheres (MS) were prepared using a novel microchannel (MC) emulsification
technique. The characteristics of the MS preparation and the O/W-MS prepared were studied. Soybean oil and medium-chain triacyglycerol
(MCT) were used as the disprrsed phase, and physiological saline was used as the continuous phase. Silicon MC with 1 to 3μm-equivalent
channel diameters were employed. A novel MC module was devised to easily recover the O/W-MS prepared. The effects of the channel
shape on the behavior of MS formation, on the MS size, and on the distribution were investigated. An MC with a terrace at
the MC outlet stably yielded micron-scale monodisperse O/W-MS; the MS had diameters of about 5 μm, and their coefficients
of variation were below 9%. Monodisperse food-grade O/W-MS with diameters of about 4 μm could be obtained by using polyglycerol
fatty acid ester as the surfactant. The size and size distribution of the recovered O/W-MS remained almost constant over 60
d, demonstrating their long-term stability. 相似文献
Expression of the SMK1 gene which encodes the yeast killer toxinSMKT is lethal in Saccharomyces cerevisiae. Effects of deletionand site-directed mutagenesis of SMK1 on the lethality and thesecretion of the gene products were examined. Deletion of theinterstitial 相似文献
A new Monte Carlo model is introduced to describe diffusion-limited aggregation (DLA) with extra forces arising from Lorentz's and/or Coulomb forces. Furthermore, we simulate a behavior of multiparticle diffusive aggregation to examine the resultant pattern of crystal in electrochemical deposition. Different patterns grown under various external forces are produced by Monte Carlo simulations. In the present model, the basic movement of particles is a random walk, with different transition probabilities in different directions, which characterizes stochastically the effect of extra forces. In case of assuming a high magnetic field, pattern formations which are qualitatively different from the standard DLA model are observed and they are successfully compared with preexisting experiments (Mogi et al., 1991). The present numerical results of electrochemical deposition show that the generated patterns strongly depend on the force acting on ions and their concentration (Sawada et al., 1986). 相似文献
Emulsion polymerization of methyl methacrylate was carried out using a mixture of anionic emulsifier, sodium dodecyl sulfate (SDS) and nonionic emulsifier, poly(oxy ethylene) nonyl phenyl ether with an average of 40 oxy ethylene units per molecule (NP-40). The rate of polymerization and the number of polymer particles produced both increased with increasing the amount of NP-40 initially charged, when NP-40 was used as the sole emulsifier. Interestingly, however, both the rate of polymerization and the number of polymer particles produced was found to decrease, when the amount of NP-40 added to the fixed amount of SDS is increased in the mixed emulsifier. On the contrary, they both increased when the amount of SDS added to the fixed amount of NP-40 is increased in the mixed emulsifier. The mixed emulsifier did not affect the number of the radicals per polymer particle at a certain number of polymer particles, but affected the number of polymer particles, thus the rate of polymerization. 相似文献