Electrically conductive paste

Property Thermally Conductive Paste Electrically Conductive Paste... 

In the manufacture of smart cards, microprocessor chips, memory chips, EEPROMs or combinations in flip- chip configuration are electrically bonded onto the circuit card using anisotropic electrically conductive paste or film adhesive (see Chapter 1). Smart cards may be contact or contactless types. In contact cards, the electrical contacts of the card connect to a card reader when the card is inserted. Contactless cards transfer data in proximity to a reader (www.smartcard.gov) without physical contact. 

The physical combination of immobilized enzymes and electrodes can be realized in several different ways. The most common are those in which the enzyme is immobilized in a membrane that is held in close proximity to the electrode surface, immobilized directly on the electrode surface with retained activity, or immobilized in an electrically conducting paste comprising a carbon-oil mixture, known as a carbon paste electrode. The enzyme substrate (and cosubstrate, if required) will diffuse from the... 

PIa.tes, Plates are the part of the cell that ultimately become the battery electrodes. The plates consist of an electrically conductive grid pasted with a lead oxide—lead sulfate paste which is the precursor to the electrode active materials which participate in the electrochemical charge—discharge reactions. 

For a large number of applications involving ceramic materials, electrical conduction behavior is dorninant. In certain oxides, borides (see Boron compounds), nitrides (qv), and carbides (qv), metallic or fast ionic conduction may occur, making these materials useful in thick-film pastes, in fuel cell apphcations (see Fuel cells), or as electrodes for use over a wide temperature range. Superconductivity is also found in special ceramic oxides, and these materials are undergoing intensive research. Other classes of ceramic materials may behave as semiconductors (qv). These materials are used in many specialized apphcations including resistance heating elements and in devices such as rectifiers, photocells, varistors, and thermistors. 

During the past 30 years considerable research has been undertaken that has led to electrically conducting polymers that do not rely on the use of fillers, the so-called intrinsically conductive polymers. Such polymers depend on the presence of particles which can transport or carry an electric charge. Two types may be distinguished ... 

PCBs and PCTs are particularly troublesome liquids because of their toxicity and persistence in the environment. They are defined as polychlorinated biphenyls, polychlorinated terphenyls, monomethyl-dibromo-diphenyl metliane, monomethyl-dichloro-diphenyl metliane or monomethyl-tetrachlorodiphenyl methane. With low electrical conductivity and heat resistance they found wide use as dielectric fluids and were formerly used as hydraulic fluids. PCBs have not been made in the UK since 1977 and whilst most new uses for the substance are banned in most countries, around two-thirds of the 1.5 million tonnes manufactured in Europe and the US prior to 1985 still remain in equipment such as transformers. PCTs have been used in the past in a restricted range of specialist industrial applications. 

Intermittent conductivity measurement controlled, with the electrode placed in the BD line before the BD valve. In this arrangement the controller program opens the BD valve for a timed period (= 1 minute), sufficient for fresh BW to flow past the electrode and an accurate electrical conductivity measurement to be taken. The BD valve remains open until the conductivity falls below a set point. Again, this arrangement is improved with the use of a cooling coil. It is the most widely employed intermittent BD arrangement for FT boilers. 

We used polycrystalline films of ZnO and Sn02 as adsorbents. The films were deposited from the water suspension of respective oxides on quartz substrates. These substrates contained initially sintered contacts made of platinum paste. The gap between contacts was of about lO" cm. All samples were initially heated in air during one hour at T 500 C. We used purified molecular oxygen an acceptor particle gas. H and Zn atoms as well as molecules of CO were used as donor particles. We monitored both the kinetics of the change of ohmic electric conductivity and the tangent of inclination angle of pre-relaxation VAC caused by adsorption of above gases and the dependence of stationary values of characteristics in question as functions of concentrations of active particles. 

Traditional alloy design emphasizes surface and structural stability, but not the electrical conductivity of the scale formed during oxidation. In SOFC interconnect applications, the oxidation scale is part of the electrical circuit, so its conductivity is important. Thus, alloying practices used in the past may not be fully compatible with high-scale electrical conductivity. For example, Si, often a residual element in alloy substrates, leads to formation of a silica sublayer between scale and metal substrate. Immiscible with chromia and electrically insulating [112], the silica sublayer would increase electrical resistance, in particular if the subscale is continuous. 

One place where soil solution from saturated soils is routinely used is in the determination of salts in soil. Salts can build up in soil in low-rainfall areas. A measure of the salt content is essential for these soils. Typically, a saturated paste of soil is made and the water filtered by vacuum filtration. The filtrate can then be analyzed for electrical conductivity and this measurement, together with calcium, magnesium, and sodium content, can be used to calculate various measures of salt content and potential detrimental effects of salts on crops and water quality. 

This past decade has seen numerous controversial studies regarding electrical conduction of DNA. Some reported high conductivity [115, 116, 118] with Crt of at most lO" S cm [115] or even superconducting properties [119], while others claimed that the carefully deionized DNA molecules are insulating [117, 120] in agreement with the old reports [121, 122] with ctri- less than 10 S cm. The controversy seems to have settled on a wide consensus that, apart from ionic conduction by the sodium gegenions, double-stranded DNA is an electrical insulator. 

The Leclanche cell, the inexpensive disposable flashlight-type cell, has been on the market for over 100 years, yet its chemistry is not completely understood. The cell consists of an outer zinc shell that acts as the anode (seen by the external circuit as the source of electrons and hence the negative terminal) and oxidizes away during operation of the cell, a carbon rod or disk that serves as the cathodic current collector (positive terminal), and a moist paste of manganese dioxide, ammonium chloride, and zinc chloride that fills the cell and acts as both the electrolyte and the source of the cathodic reaction (reduction of MnIV). Usually, graphite in the form of carbon black is added to the paste to increase the electrical conductivity. The basic reactions are... 

In the past, KOH eluent was usually contaminated with CO -. When CO passes through the suppressor after the ion chromatography column, it is converted into H2C03, which has some electrical conductivity that interferes with detection of analytes. In gradient... 

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