New grid bathymetry dataset covering the whole South China Sea with a spatial resolution of 1 min (1/60 degrees) has been developed by compiling sounding data derived from various sources including recent multi-beam sounding records. This dataset was found to resolve more realistic bottom features than existing global DTMs (etopo1, gebco08, gebco2014) especially at shallow regions such as Spratly Islands and the Java Sea.
Ag particles loaded mesoporous zirconia oxide (ZrO2) and titanium oxide (TiO2) nanofibers were prepared by electrospinning methods followed by calcination at 500-600oC. The crystal structure of the Ag particles were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fiber diameters for the ZrO2 and TiO2 mats were in the range of 60-160 nm and 50-450 nm, respectively. X-ray line broadening analysis showed that they were composed of smaller sized crystallites. Nitrogen-adsorption studies revealed that the ZrO2 and TiO2 fibers have both mesoporous and macroporous structures, which were originated from the aggregation of smaller crystallites than the fiber diameters and the interspaces formed by randomly oriented nanofibers. The deposition of Ag on the fibers followed by calcination at 500oC changed the distribution of the mesopore sizes.
A wind tunnel experiment to assess the flow characteristics of the wake behind a spire mounted normal to the wind tunnel floor was conducted to clarify the interaction between the wake flow and the wall shear boundary layer. To reproduce the contrasting boundary layer depth, two types of walls—a smooth wall and a regular cube array—were adopted; for each wall, the spanwise distribution of the streamwise velocity was measured at two downwind positions and seven heights within and above the wall boundary layer with and without a spire. The spanwise distribution of the wake generated by the spire far above the wall boundary layer with low turbulence agreed with the well-known function for two-dimensional (2D) wake flow, derived theoretically from the gradient-diffusion model, despite the weak asymmetry of the inflow. In contrast, the spanwise distribution of the wake within or near the outer edge of the wall boundary layer showed different trends from that of the 2D wake flow. In the former, the expansion of the wake width is compressed in the lateral direction by the turbulence of the wall boundary layer and the velocity deficit of the wake is sustained far from the spire.
This paper reports the results of flow field analysis within and above a two-dimensional street canyon with various overhang lengths using large-eddy simulation (LES). Simulations were conducted for a constant canyon aspect ratio of W/H = 3, where W is the street width and H is the building height. Three different overhang lengths were simulated with P = 0H, 0.5H, and 1H in order to derive the mean and instantaneous flow characteristics. The results are compared with wind tunnel experiments for validation. The LES results of the mean flow with the P = 0H condition agree fairly well with the wind tunnel data. However, profiles of the standard deviation for the streamwise and vertical velocity components show large discrepancies at all measured locations. In addition, an increase in overhang length on both building facades significantly modifies the in-canyon flow pattern by limiting the penetration of the bulk flow into the canyon layer.
CuInS2 (CIS) fluorescent nanocrystals (NCs) were obtained by heating an organic metal complex. The photoluminescence (PL) originated from the donor-acceptor, and the quantum yield (QY) was achieved at 6%. Furthermore, we added some metal ions (Zn2+, Cd2+ or Ag+) by the post heat-treatment in the organic coordinating solvent in order to tune the PL wavelength of NCs. By this post treatment, the alteration of NCs structure was suggested, such as changing into an alloying and composite structure. In Zn-treated, the PL wavelength was widely tuned from 535 to 650 nm by alloying between CIS and ZnS. Moreover, PL intensity was increased with these structure alterations. In particular, the materials treated with Zn2+ or Cd2+ achieved respective QY of 25% and 40%.
The dependences of the VHF plasma parameters on the gas pressure and power were examined by using the Laser Thomson scattering method, where the VHF plasma was produced in the high pressure region by the balanced power feeding method. It was found that the balanced power feeding method provides a high electron density plasma with low electron temperature at high pressures. This characteristics were confirmed by calculations using a 2-dimensional simulation code.
Deuterium retention and trapping in tungsten plasma sprayed layers after low energy plasma irradiation was investigated by means of thermal desorption technique. Plasma irradiation at low temperatures ( 650 K) showed significant increase of the retention in the plasma sprayed layers contrary to the polycrystalline material. Thermal desorption spectra showed extremely high temperatures of the peak positions which are non-typical for the tungsten materials. The possible reasons for such high deuterium retention in the plasma sprayed layers after irradiation at high temperatures and the possible trapping mechanisms are discussed.
m was investigated using the helicoid spring specimen technique. The testing temperatures ranged from 423 K to 523 K (0.47 to 0.58 Tm) and the applied stresses from 0.20 to . It was found that under the above conditions, viscous creep of Bingham type occurs, characterized by a threshold stress which decreases with increasing temperature. The activation energy is Qc = 44 7 kJ/mol. No microstructural changes were observed in recrystallized and the as-crept specimens. The measured creep rates were found to be four orders faster than that predicted by Coble creep model.
An outdoor measurement was performed during fine weather with a scale-model array of cubical obstacles (size 100mm, 25% packing density, lattice-type square layout) that represent an idealized urban tissue. Surface temperature was recorded with high-frequency (10Hz) infrared camera, along with wind speed and solar radiation. Complementarily, air temperature was also measured at three heights in the near-wall region of a block surface using fine-wire thermocouples. Results showed the similarity of distribution between surface temperature and scalar transfer coefficient. We also found that 10s averaging period may be appropriate for the analysis of surface temperature fluctuation affected by turbulent air flow. In the near-wall region under particularly calm wind condition, air temperature fluctuation caused by a hot plume arising from the warmed surface was observed. The method presented in this study seems to be a promising tool to analyze surface temperature characteristics of scale-models in urban climate studies.
The toroidal field power supply of HL-2A Tokamak operated in pulse mode is fed by two sets of motor generators with corresponding diode rectifiers. Each six-phase generator has two star stator windings with a phase difference of 30o between them. In this paper, the model of six-phase generator with rectifier load is built and toroidal field discharge operated in pulse mode is simulated based on dual DQ0 transformation.
In this paper, the performance of a CO2 based hybrid compression-adsorption cooling cycle is presented based on a transient mathematical model. In the proposed hybrid cycle two stage compression have been performed where CO2 passes through the mechanical compressor at the low-pressure side. The compressed CO2 from the mechanical compressor is then adsorbed in the designated adsorbers of the adsorption cycle. The chiller response as well as the chiller performance in terms of cooling capacity and coefficient of performance (COP) are investigated for different desorption pressures and gas cooler outlet temperatures. This novel hybrid cooling system attains similar cooling power and two to three folds COP values than those of the conventional CO2 based vapor compression cycle with the same operating conditions. Therefore, the proposed system seems to be promising for automotive air-conditioning application where waste heat from engine is esteemed.
†We evaluated the thermal conductivity of AlN ceramic plates as a potential material of a thermal guide for cooling SQUID in cryocooler cooled SQUID systems. We found that the AlN ceramic plate does not show a good thermal conductivity at very low temperature. We tried to enhance its thermal conductivity by attaching a lot of thin insulated copper wires in parallel with each other to cover a back plane of the plate. With this enhancement we succeeded to operate a double relaxation oscillation SQUID (DROS) first-order gradiometer. Comparison of measurement results on white noise level between two cases where DROS was attached to a copper plate thermal guide and where it was attached to a modified AlN thermal guide shows almost 5 time reduction in noise floor with the latter plate.
This article deals with the experimental study of adsorption rate of R507A on highly porous activated carbon of type Maxsorb III by constant volume variable pressure (CVVP) method over a temperature ranging from 20 to 60oC. These data are useful for the operation of adsorption chillers and these data are unavailable in the literature. Data obtained from the kinetic studies were treated according to the various kinetic models with the Fickian diffusion model being the most suitable overall. Guided by the experimental measurements, the surface diffusion is also estimated and is found that it follows the classical Arrhenius law within the experimental range.
