Conduction plane glasses

We should not think that heat is lost only from the copper side. The usual laminate (board material) used for SMT (surface mount technology) applications is epoxy-glass FR4, which is a fairly good conductor of heat. So some of the heat from the side on which the device is mounted does get across to the other side, where it contacts the air and helps reduce the thermal resistance. Therefore, just putting a copper plane on the other side also helps, but only by about 10 to 20%. Note that this opposite copper plane need not even be electrically the same point it could for example just be the usual ground plane. A much greater reduction of thermal resistance (by about 50 to 70%) can be produced if a cluster of small vias (thermal vias) are employed to conduct the heat from the component side to the opposite side of the PCB. 

The experiments on the iodine separation were conducted as follows. A tubular vessel of pyrex glass, having at one end a plane window and at the other end a conical light-trap, was evacuated and then filled with iodine at about 0.17 mm. pressure, and then with hexene at about 6 mm. partial pressure. The tube was then subjected to the intense light from two Cooper-Hewitt glass mercury arcs, using a filter of 0.05 molal potassium dichromate 2 cm. in thickness to cut off all radiations on the violet side of the green mercury line. The lamps were rim at considerably below the rated capacity, and were cooled by a blast of air to keep the emission lines as narrow as possible. 

Electrical conductance The conductance measurements were made in a glass cell consisting ot two equivalent electrode sections. Circular platinized platinum electrodes parallel to the plane of the membrane were embedded in each section. The membrane area was 0.98 cm2. Resistance measurements were made with and without the membrane in O.IN NaCl solution. 

Unlike STM and AFM tips, which are sharp cones, a typical SECM tip is a conductive disk surrounded by the flat ring of insulating glass whose thickness is equivalent to several disk radii. Thus, a proper alignment of the tip with respect to the substrate surface is crucial (see also Section IV.B.2). Unless the tip surface is flat and strictly parallel to the substrate plane, the insulator touches the substrate first and prevents the conductive disk from coming close to its... 

It prefers pyramidal structure with its lone pair electrons projecting away from the plane of four oxygens. This lone pair, indeed, impedes the motion of alkali ions in alkali lead borate glasses stickiness of the lone pair) (Ganguli et al., 1999) leading to rather low ionic conductivity in spite of the open network structures. 

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