Cooling of rubidium atoms in pulsed diffuse laser light

This paper reports an experiment on laser cooling of STRb atoms in pulsed diffuse light, which is the key step towards a compact cold atom clock. It deduces an empirical formula to simulate the pulse cooling process based on the loading of cold atoms in cooling time and the loss in the dead time, which is in agreement with the experimental data. The formula gives a reference to select the parameters for the cold atom clock.

Effect of sodium nitroprusside on the microrheological properties of red blood cells in different media

Red blood cell(RBC)aggregation as well as their deformation significantly affects blood microrheology.These processes depend on various factors,one of which is concentration of the nitric oxide,one of the main signaling molecule in the bloodstream.The purpose of this study was to investigate the effect of nitric oxide on the microrheological properties of red blood cells(RBCs)in RBC samples of various media after the addition of nitric oxide donor sodium nitroprusside in vitro.Microrheological properties were measured using laser aggregometer and ektacytometer based on diffuse light scattering and diffraction of laser light on a suspension of RBCs,respectively.The study found that heparin-stabilized blood showed increased RBC aggregation and deformation with sodium nitroprusside concentrations of 100,and 200M,while EDTA-stabilized blood showed slightly decreased aggregation and unchanged deformation.With washed RBCs in dextran solution,the addition of sodium nitroprusside(in the concentrations of 100,and 200M)resulted in decreased aggregation and increased deformation.These-ndings aid in our understanding of nitric oxide's effect on RBC microrheological properties.

A SIMPLE METHOD TO DETERMINE THE DAYLIGHT FACTOR FROM THE VERTICAL DAYLIGHT FACTOR IN DIFFERENT STREET CANYON GEOMETRY

This paper investigates the main characteristics of daylight on any window in a street canyon.The sky component and the light reflected from the surroundings are described to determine the vertical daylight factor(VDF).Several street canyon types are characterized taking into account their different height/width and any level of the window is analysed.A simple calculation method uses trigonometric equations based on the sky and the geometry of the canyon.The results were previ-ously evaluated considering different daylight procedures obtained by other studies.This study reveals that the reflectance within an urban canyon plays an important role in the amount of daylight onto any window with more relevance in a deep canyon and low sky view.The graphical presentation that result from this investiga-tion can rapidly assist building and urban designers in an early stage design where assumptions and the lay out of the main design take place.

Artificial neural-network-based visible light positioning algorithm with a diffuse optical channel

Visible light positioning becomes popular recently. However, its performance is degraded by the indoor diffuse optical channel. An artificial neural-network-based visible light positioning algorithm is proposed in this Letter, and a trained neural network is used to achieve positioning with a diffuse channel. Simulations are made to evaluate the proposed positioning algorithm. Results show that the average positioning error is reduced about 13 times, and the positioning time is reduced about two magnitudes. Moreover, the proposed algorithm is robust with a different field-of-view of the receiver and the refiectivity of the wall, which is suitable for various position- ing applications.

Reconstruction of 3D light distribution produced by cylindrical diffuser in deep tissues based on photoacoustic imaging

Measurement of light distribution in biological tissue contributes to selecting strategy and optimizing dose for biomedical application. In this letter, a photoacoustic method combined with Monte Carlo simulation was used to estimate the three-dimensional light distribution in biological tissue. The light distribution was produced by a cylindrical diffuser which interposed into tissues. The light profiles obtained by the method were compared to those detected by photo diodes. The experimental results demonstrate the feasibility of this method. The approach can play a significant role for photo-dosimetry in biomedical phototherapy.

A fractal concentrator of direct and indirect sunlight

A novel concept for concentrating both direct and indirect sunlight employing a combination of waveguiding and refractive optics is presented.More specifically,it is based on both the individual and the collective focusing effects of an array of refractive optical elements of specific geometry.An analytical framework and design principles regarding the geometry of the optical elements taking into account Fresnel reflection and refraction are presented.The principle of operation along with loss mechanisms and acceptance angles are discussed in detail.Ray-tracing simulations of a light concentrator designed accordingly indicate transmittance>90%with acceptance angles of≤65°at 3 suns for moderate refractive indices.It is further numerically demonstrated that the new approach allows the utilization of the dominant fraction of the solar radiation by harvesting the waste heat in addition to photovoltaic conversion with an operating energy efficiency for diffuse light>70%.

NEWS AND NOTES

Lung biopsies examined with light microscope and electron microscope were performed in 34 cases of diffuse pulmonary disease.Open lung biopsy was done in 2 cases,