An automatic digital Q-meter for low values of Q

An automatic digital Q-meter suitable for measuring low Q-factors at low frequencies is described. It Uses a microcomputer. In a conventional digital Q-meter, the number of damped oscillations which occurs in the time interval between the initial peak and the damped peak exp (? n) times smaller than the first one, corresponds to the numerical value of the Q-factor. For small Q-factors a considerable error occurs in this procedure, and the error can be eliminated by the procedure presented in this paper.     

On infinite-dimensional pole-zero cancellations

Pole-zero cancellation for infinite-dimensional linear systems is considered. It is proved that the cascade connection of two systems is unobservable if there is a pole-zero cancellation between the spectrum of the first system and the zeros of the second system. The converse is also proved, under some hypotheses, if one of the systems is finite-dimensional.     

Extraction of Volatile Compounds from Aqueous Solution using Micro Bubble, Gaseous, Supercritical and Liquid Carbon Dioxide

When separating volatile compounds from aqueous solution using supercritical carbon dioxide (SC CO₂), methods to bring SC CO₂ into contact with volatile compounds in the solution are very important. An extraction using micro bubble, gaseous, supercritical, and liquid CO₂ generated by a filter nozzle was carried out. Under optimal conditions (20 MPa, 35°C), > 95% of volatile compounds consisting of 6 to 12 carbon atoms could be removed by extraction for 40 min at CO₂ flow rate, 4.0 g/min. Extraction at 35°C could achieve either a selective or nonselective separation by adjusting the extraction pressure, since the effect of pressure on extraction ratio was most significant at 35°C.     

Degradation of Oval-Filefish Meat Gel Caused by Myofibrillar Proteinase(s)

The textural degradation of oval-filefish meat gel accompanying the increase of peptides and the breakdown of myosin heavy chain was caused by proteinase(s) tightly associated with myofibrils. Leupeptin and n-butanol inhibited the proteolytic activity to some degree. The existence of an endogenous inhibitor for the proteolytic activity in the sarcoplasm was also demonstrated.     

Sorption of Volatile Compounds in Aqueous Solution by Ethylene-Vinyl Alcohol Copolymer Films

Sorption of volatile compounds by ethylene-vinyl alcohol copolymer (EVOH) films from an aqueous solution was investigated to evaluate the merit of their use for food packaging. With regard to EVOH, equilibrium swelling values gave rise to a bimodal solubility parameter distribution with maxima at δ values of 8.5 assigned to ethylene units and 14.5 to vinyl alcohol units. Comparing distribution ratios of EVOH with those of middle-density polyethylene (MDPE), the ratios were 1:100 for terpene hydrocarbons, 1:10 for esters, 1:2 for alcohols, and almost 1:1 for aldehydes. By biaxial orientation of EVOH film, the sorption could be depressed below 60%. These results suggested EVOH films are more appropriate than MDPE for food container lining.     

New solution to the inverse regulator problem by the polynomial matrix method

This paper gives a new criterion for the inverse regulator problem in terms of polynomial matrix fractions. The generalized Kalman equation in polynomial matrix form leads to a necessary and sufficient condition for a stable feedback law to be optimal for some (unknown) quadratic performance index. This criterion consists of (i) a symmetric factorizability of a polynomial matrix, and (ii) a polynomial-type criterion that guarantees detectability. The relationship between the Riccati and Kalman equations is also established. Finally, an example is given to illustrate the new result in contrast with the existing result.     

Effects of homogenisation conditions on the physical properties of high-fat ice cream

The effect of homogenisation pressure on the physical properties of high-fat ice cream was investigated. Nonhomogenised ice cream was hard, with low resistance to meltdown, and ice crystals grew rapidly therein. Fat globule networks were not formed in the nonhomogenised ice cream. The ice cream homogenised at 5 MPa or more was harder and showed a higher resistance to meltdown. Ice crystals in the ice cream homogenised at 5 MPa or more grew slowly. The physical properties of each ice cream varied with homogenisations from 5 to 25 MPa and could be controlled by homogenisation pressure.     

Galactose-inducible Expression Systems in Candida maltosa using Promoters of Newly-isolated GAL1 and GAL10 Genes

The GAL1 and GAL10 gene cluster encoding the enzymes of galactose utilization was isolated from an asporogenic yeast, Candida maltosa. The structure of the gene cluster in which both genes were divergently transcribed from the central promoter region resembled those of some other yeasts. The expression of both genes was strongly induced by galactose and repressed by glucose in the medium. Galactose-inducible expression vectors in C. maltosa were constructed on low- and high-copy number plasmids using the promoter regions of both genes. With these vectors and the β-galactosidase gene from Kluyveromyces lactis as a reporter, galactose-inducible expression was confirmed. Homologous overexpression of members of the cytochrome P-450 gene family in C. maltosa was also successful by using a high-copy-number vector under the control of these promoters. © 1997 by John Wiley & Sons, Ltd.     

Control of Autonomous Mobile Robot Using Map Matching with Optimized Search Range

Accurate estimation of self‐position is indispensable for autonomous mobile robots. Map‐matching‐based self‐positioning is a promising method; however, adequate matching area selection is an issue to be solved. In this paper, we propose an adjustable map matching method that remedies a defect of the conventional template matching technology. The proposed method was evaluated experimentally, and the results confirmed the advantages of the proposed method.     

Application of a switched-capacitor circuit to converting a two-wire to a four-wire hybrid function

A new switched-capacitor circuit using an integral feedback capacitor is proposed. A capacitor in a CR integrator which uses an operational amplifier is regarded as an information transmission element. By switching this capacitor from the input side to the output side periodically, a sampled-data transmission circuit is produced which has better frequency response than that of an ordinary integrator. The technique is shown applied to a solid-state two-wire to four-wire hybrid function in telephone communication.