On application of heat-conductive plastics in LED technology

A comparative analysis of the characteristics of heat-conducting plastic was performed. The results of the thermal measurements of two of the same type 3W LED modules installed on heat sink with the same area of heat-dissipating surface made of aluminum and heat-conducting polymer have been presented. It has been shown that the overheating of LED module mounted on the heat-conducting polymer heat sink is 2…3 °С higher than that on the aluminum heat sink (thermal conductivity is 20 times higher). The ranges of applicability of the heat-conducting plastics in LED technology have been determined

Quasi-active thermal control in LED street lights

In this paper, the hollow heat sink has been studied. The physical and mathematical model of a hollow heat sink and CFD modeling are proposed for fitting the experimental results. It has been shown that the model of a hollow heat sink allows to calculate the velocity (and temperature) of the air flow coming out of the hollow heat sink, to determine its dependence on the angle of the dissipated thermal power, length, and degree of fin and cross-sectional area of the hollow heat sink. The influence of the geometry of the inlets/outlets on the heat removal was analyzed. It has been shown that the efficiency of the quasi-active system increases significantly in the presence of external wind through the so-called “effect of spray

Nanomonitoring of ceramic surface

The current paper considers the feasibility of application of novel supramolecular complexes based on nanodiamond particles and rear earth elements (ND-REE) as perspective luminescent material for surface mapping and discontinues of minimal size detection. The new hybrid supramolecular complex of composition (ND)m[Eu (BPhen.)2(NO3)2]m has been developed and fabricated. Spectral-luminescent and structural properties of complex have been investigated. It has been shown that the complex has broad excitation bands from 200 to 400 nm, very effective red long-lifetime luminescence in the millisecond range and high quantum yield (about 80%). Using scanning electron microscopy the morphology and size of the complexes have been investigated. The complexes with NDs look like finer grains of spherical shape without sharp corner pieces. The size of primary particles varies from 0.1μm, which are capable to agglomeration up to 10 μm in average. Using the fine suspension of ND-containing complex in isopropyl alcohol as luminescent penetrant for ceramic surface status inspection it has been demonstrated that this type of complexes can be revealed on surface under UV-irradiation as bright red indicated traces

Visible and IR Photoluminescence of Erbium Doped Porous Silicon Films

Two different oxidized porous silicon samples were saturated with lantanum oxysulfide luminophors doped with Er and Yb from their colloidal alcoholic solutions. One of the samples was annealed at 700 degrees C for 10 min, another was heat treated at 100 degrees C for 6h, After annealing, both exhibited room-temperature Er3+ photoluminescence which increased significantly under excitation at wavelengths corresponding to the absorption band of porous silicon. In addition, the sample containing the largest amount of Yb3+ revealed a strong Yb3+ photoluminescence at 985 nm