We have developed an instrument to measure trace concentrations of small hydride species in gases using continuous-wave cavity ring-down spectroscopy with near-infrared diode laser excitation. An rms baseline equivalent absorbance of 9.2 x 10(-11) cm(-1)/square root(n) is found, where n is the number of ring-down transients. When the 1396.376-nm absorption line of water is used, this correspond...

The natural convection of phase change material (PCM) in a two-dimensional square cavity is numerically analyzed. consists heat surface with constant total heated area and adiabatic wall. Grashof Prandtl numbers for the PCM (n-eicosane melting temperature, Tmelt=36°C) basic LHS system are 9 × 10^5 62.7, respectively, at 350.15K. mass, momentum energy balance equations were considered. Three hea...

In this paper, natural convection melting in a square cavity with gradient porous media is numerically studied at pore-scale level by adopting the lattice Boltzmann method. To generate media, Monte Carlo technique based on random sampling principle used. The effects of several factors, such as Rayleigh number, porosity structure, direction, and particle diameters are investigated detail. Based ...

Spectroscopic detection of ethane in the 3-microm wavelength region was performed by means of a cw optical parametric oscillator and cavity leak-out. We achieved a minimum detectable absorption coefficient of 1.6 x 10(-10) cm 1/square root of Hz, corresponding to an ethane detection limit of 6 parts per trillion/square root of Hz. For 3-min integration time the detection limit was 0.5 parts per...

A study on heat and mass transfer behaviour on an anisotropic porous medium embedded in square cavity/annulus is conducted using Incompressibe Smoothed Particle Hydrodynamics (ISPH) method. In the case of square cavity, the left wall has hot temperature Th and mass Ch and the right wall has cool temperature Tc and mass Cc and both of the top and bottom walls are adiabatic. While in the case of ...

We propose a novel method to stabilize two external cavity lasers for optical generation of microwave and millimeter wave signals. In our method, two 1550-nm, servo-locked external cavity laser diodes (ECLDs) are simultaneously locked to two resonance frequencies of a single Fabry-Perot optical cavity. The stabilization of two lasers are realized by introducing classical FM sideband technique. ...

Abstract. Natural convection heat transfer in a square cavity induced by heated plate is studied numerically. Top and bottom of the cavity are adiabatic, the two vertical walls of the cavity have constant temperature lower than the plate’s temperature. The flow is assumed to be two-dimensional. The discretized equations were solved by finite difference method using Alternating Direction Implici...