Electrical potential pattern

Figure 8 shows the electrical potential pattern from 8 channels for five kinds of taste qualities of sour, salty, bitter, sweet and umami. 

We attempted to make an artificial taste solution, which shows a similar taste to some commercial aqueous drinks, by combination of basic taste substances by comparing electrical potential patterns of the taste sensor [22],... 

The above-mentioned 256 mixed solutions were measured with the multichannel taste sensor. Therefore, data on the output electrical potential pattern were taken for the 256 solutions. While the data on each channel output were dispersed discretely in the four-dimensional space constructed from four different concentrations, we approximated them by a quadratic function of the concentrations. As a result, eight quadratic functions were obtained. The data can be regarded as expressed by a set of eight different functions (corresponding to 8 channels) of concentrations of four taste substances. 

As test aqueous drinks, two commercial drinks of different brands were chosen. Figure 10 shows the electrical potential patterns of these two drinks. While they are not so different, the discrimination is easy because of standard deviations of 2mV. We attempted to fit the above patterns constructed from eight functions to the output electrical potential pattern of one of commercial drinks (let us call "drink A" for convenience) by minimizing the following value. 

Figure 13 shows the effect of temperature on the electrical potential pattern of a certain brand of beer [22], The pattern was drastically affected by temperature. It implies that the taste was largely changed with temperature, as experienced usually. It is to be noted that the chemical component is almost the same even at different temperatures. 

The tastes of the five kinds of tomatoes were predicted by comparing the output electrical potential patterns for tomatoes with the results of the preliminary experiment. 

The test foods studied here were five kinds of tomatoes. When eating food, humans first masticate the food with their teeth and then taste it. Therefore, we used a mixer in place of teeth and crushed tomatoes before measuring them. The preconditions were established by keeping the electrode immersed in standard juice, i.e., commercial canned tomato juice without NaCl added, for a long period of time. The origin of the output pattern was taken under these preconditions. Standard juice was used for the reference electrical potential pattern. The standard deviations between different lots of membrane were about 3mV. The same set of the eight membranes was used throughout the measurements for all tomatoes. 

Figure 16 shows examples of the response pattern for one sample each of five brands of tomatoes. Different brands of tomatoes were distinguished by the shapes of the output electrical potential patterns. Therefore, tomatoes of the same brand can be considered to have a taste with similar proportions the difference in taste among tomatoes of the same brand may be due, mainly, to the difference in magnitude of taste, because the output electrical potential changed linearly with the concentrations of taste substances in a narrow range [18, 21]. 

As the third method, recent experiment has been successful in the quantification of taste of various brands of tomatoes [21] a preliminary measurement was performed to study the change in electrical potential pattern with addition of basic taste substances to the standard taste solution, e.g., commercial tomato juice without NaCl, together with the measurements on... 

The overall pattern of behaviour of titanium in aqueous environments is perhaps best understood by consideration of the electrochemical characteristics of the metal/oxide and oxide-electrolyte system. The thermodynamic stability of oxides is dependent upon the electrical potential between the metal and the solution and the pH (see Section 1.4). The Ti/HjO system has been considered by Pourbaix". The thermodynamic stability of an... 

Qian and Bau [144] have analyzed such electroosmotic flow cells with embedded electrodes on the basis of the Stokes equation with Helmholtz-Smoluchowski boimdary conditions on the channel walls. They considered electrode arrays with a certain periodicity, i.e. after k electrodes the imposed pattern of electric potentials repeats itself An analytic solution of the Stokes equation was obtained in the form of a Eourier series. Specifically, they analyzed the electroosmotic flow patterns with regard to mixing applications. A simple recirculating flow pattern such as the one... 

Chemical aspects of taste receptor functions can he studied by recording the patterns of electrical potentials in receptor cells while the cells are being stimulated with pure chemicals of known structures and properties. Since the mid-1950s, when this method was first successfully applied to single taste receptor cells, using receptors on Ihe mouth parts of a fly. many earlier theories of taste stimulation have been revised. 

Figure 12 shows the response patterns to 8 different brands of beer among 36 brands measured [20]. The patterns were measured relative to a certain beer as a standard. Although the difference in electrical potential between different brands was a few mV or more, each beer was easily distinguished from the other by these patterns because of the high reproducibility and... 

Figure 12. Output patterns for eight brands of beer. The origin of the electric potential was taken to some beer Kl.

The different concentrations of the ion inside and outside the cells cause a slight electrical potential difference across the cell membrane. It is very small, approximately 100 mV. However, any changes in the concentrations of the ions present change this value. Thus concentrations of ions and electrical charges must be synchronized to allow the cell s materials and charges to flow across a membrane. This cycle in the cells of the heart causes the regular pattern of the heart beat and any imbalance of electrical activity or ion imbalance can cause a malfunction of the... 

Figure 3.18 Interdigital transducer, formed by patterning electrodes on the surface of a piezoelectric crystal, for exciting surface acoustic waves (a) SAW electrical potential,...

Massive electrochemical attack known as galvanic corrosion [58,59] is the most severe form of copper corrosion. It can completely remove the copper from the structures (Figs. 17.25 and 17.26). It can occur when the wafers are exposed to a corrosive electrolyte for an extended period. It can also occur if the slurry does not contain enough or effective corrosion inhibitor. The source of such a galvanic potential on the patterned copper surface may be due to the fact that some copper structures connected to transistors have a different electrical potential than the rest of the wafer surface. Another possible cause of this type of galvanic potential is related to the barrier material induced metal metal battery effect. Most copper CMP slurries have been developed for Cu structures with Ta or TaN as a barrier material. In some cases, other metals may also be used in addition to the barrier metal. For example, a metal hard mask could contribute to the galvanic corrosion effects. It is also possible that some types of copper are more susceptible to corrosion that others. The grain... 

In an electron microscope, the electron beam is produced by an electron gun, in which the electrons are boiled off a heated filament and then accelerated by a highly stabilized electrical potential difference of some hundreds of kilovolts. An electron beam produced in this way is not coherent, but its degree of coherence can be understood in terms of the concepts of optical coherence theory. Later chapters will show that the nature of electron diffraction patterns from crystals that exhibit long-period superstructures (which are not uncommon in many important rockforming minerals) depends critically on the degree of spatial coherence of the incident electron beam. Therefore, it is important to conclude this chapter with a brief review of the basic ideas of optical coherence. A detailed account of the theory is given by Born and Wolf (1965). 

Sustained contraction of muscle fibers produces repetitive electrical potentials in them that increase in rapidity with strength of contraction and in number as more motor units take part. These potentials may be conducted from a coaxial needle electrode in the muscle, amplified, and their amplitude and frequency analyzed and recorded on a cathode-ray oscilloscope as the very typical full interference pattern of normal voluntary contraction. Characteristic departures from this normal electro-myogram are of very great importance in the diagnosis of muscle disease (B21a). 

There is also some debate as to how to interpret the exact start and end points of the various cardiac phases from an EGG. The actual changes are based on altered ionic balances across cell membranes, which move in cyclic patterns through the heart tissue and are manifested externally as minute changes in skin electrical potential. An EGG uses multiple leads to pick up the pattern of changes and so is an indirect observation that must be interpreted by a professional. 

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