A numerical model was developed to simulate neutrally stratified air flow over and through a forest edge. The spatially averaged equations for turbulent flow in vegetation canopies are derived as the governing equations. A first-order closure scheme with the capability of accounting for the bulk momentum transport process in vegetation canopies is employed. The averaged equations are solved numerically by a fractional time-step method and successive relaxation. The asymptotic solution in time is regarded as the steady-state solution. Comparisons of model output to the field measurements of Raynor (1971) indicate that the model provides a realistic mean flow.Momentum balance computations show that the pressure gradient induced by the wind blowing against the forest edge is significant and has the same order of magnitude as the drag force in the edge region. The edge effect involves the generation of drag forces, the appearance of a large pressure gradient, the upward deflection of mean flow and the transport of momentum into the edge of the canopy. A 4 A al3 ;: Cd f" Ffi h K (11) k I n n 4 P3 P R, t T ui, u, 11: U/l List of Symbols leaf surface area density (m* mm") reference value of A (m2 m-s) (YP interfacial area constant (0.04 m s-r) constant (0.8 mZ) drag coefficient zero plane displacement (m) Coriolis parameter drag force per unit mass (m sA2) height of a canopy (m) turbulent diffusivity (m* s-r) von Karman constant (0.4) mixing length (m) volume porosity or time level unit normal vector directional cosine of n pressure (N mm*) stress tensor (m* s-~) time (s) time interval for averaging (s) velocity component (m s-r) auxiliary velocity (m s-r) wind speed at the top of a canopy (m s-r) Boundary-Layer Meteorology 51: 179-197, 1990. 0 1990 Kluwer Academic Publishers. Printed in the Netherlands. 180 ZHENJIA Ll ET AL. deviation from temporal averaged velocity (m SC') deviation from spatially averaged velocity (m SC') volume (m") geostrophic wind velocity (m s-') local velocity of the interface (m s-l) coordinate (m) height (m) roughness length (m) air density (kg m-") Kronecker delta a scalar variable p/p (m2 s-*) finite difference in space Laplacian operator shear stress tensor (m' ss*) kinematic viscosity (m' s-l) time average spatial average
A micro-plate magnetic chemiluminescence immunoassay was developed for rapid and high throughput detection of carcinoembryonic antigens (CEA) in human sera. This method was based on a sandwich immunoreaction of fluorescein isothiocyanate (FITC)-labeled anti-CEA antibodies, CEA antigens, and horseradish peroxidase (HRP)-conjugated anti-CEA antibodies in micro-plate. The immunomagnetic particles coated with anti-FITC antibodies were used as the solid phase for the immunoassay. The separation procedure was carried out by a magnetic plate adaptor and the luminol-hydrogen peroxide (H 2 O 2 )-HRP system was employed for the chemiluminescence detection. The proposed method combined the advantages of the micro-plate reactor and magnetic particle separation technology with the linear range of 5-250 ng mL
1. The detection limit of CEA was 0.61 ng mL
1. The coefficient of the variation was less than 7% and 13% for intra-assay and inter-assay precision, respectively. Compared with the commercial micro-plate chemiluminescent kit, the proposed method showed a good correlation. micro-plate magnetic chemiluminescence immunoassay, carcinoembryonic antigen, tumor marker
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