Gap symmetry and intrinsic intraplane pinning of untwinned YBa2Cu3O7 single crystals

The interplane (cb) and intraplane (ab) anisotropy of untwinned YBa₂ Cu₃0₇ single crystals has been investigated by means of the torque magnetometry. To extract the reversible and irreversible components, the torque was measured as a function of increasing angle as well as decreasing angle. The interplane irreversible torque _irr shows two-fold peaks at _c =90 ° and270 ° (of half width11 ° at77 K) due to the well-known intrinsic interplane pinning. A novel intrinsic pinning has been discovered in the intraplane irreversible torque, i.e., _irr shows four-fold peaks of half width20° at77 K when _a =0 °, 90 °, 180 ° and270 °. We argue that the intrinsic intraplane pinning comes from the four-fold nature of the gap parameter.     

A genetic approach to the design of autonomous agents for futures trading

We propose a genetic algorithm-based method for designing an autonomous trader agent. The task of the proposed method is to find an optimal set of fuzzy if–then rules that best represents the behavior of a target trader agent. A highly profitable trader agent is used as the target in the proposed genetic algorithm. A trading history for the target agent is obtained from a series of futures trading. The antecedent part of fuzzy if–then rules considers time-series data of spot prices, while the consequent part indicates the order of trade (Buy, Sell, or No action) with its degree of certainty. The proposed method determines the antecedent part of fuzzy if–then rules. The consequent part of fuzzy if–then rules is automatically determined from the trading history of the target trader agent. The autonomous trader agent designed by the proposed genetic algorithm consists of a fixed number of fuzzy if–then rules. The decision of the autonomous trader agent is made by fuzzy inference from the time-series data of spot prices. This work was presented in part at the 11th International Symposium on Artificial Life and Robotics, Oita, Japan, January 23–25, 2006     

Adsorption isotherms of pigments from alkali-refined vegetable oils with clay minerals

Adsorption isotherms of pigments from alkali-refined oils (rapeseed, soybean, wheatgerm, safflower, corn, cottonseed and sunflower) were measured to investigate the applicability of the Langmuir and Freundlich equations and to elucidate the adsorption characteristics of pigments on sepiolites and standard activated clay. The Freundlich equation was more applicable to the experimental adsorption isotherms. The equilibrium amount adsorbed, acidity, pore size distribution and inflection of the Freundlich isotherms could be explained by assuming that pigments were adsorbed on the stronger acid sites in smaller pores at low concentration, and then in the larger ones when the concentration increased. The amount adsorbed increased with a rise in adsorption temperatures from 70 to 110°C, and the heat of adsorption was below 10 kcal/mol. The results indicate that pigments were physically adsorbed on the acid sites activated at higher adsorption temperatures.     

Colorimetric microdetermination of sulphites in foods by use of the modified rankine apparatus. IV.

Summary Detection and determination of traces of sulphites in foods was attempted by use of the modified Rankine apparatus and pararosaniline colorimetry. Replacement of alkaline titration reported previously by pararosaniline colorimetry lowered the absolute detection limit from 30 g (titration method) to 2 g. In view of clean analysis, in the color developing system, 0.1 N-sodium hydroxide was used in place of mercuric chloride solution commonly used as an absorbant of sulphites. In order to prevent oxidative decomposition of sulphites during operation, nitrogen gas was used as carrier instead of air. Dimedone and sodium azide were used for the elimination of aldehydes and nitrites, respecitvely, in the sample, which will disturb the color development of sulphites with pararosaniline-formaldehyde reagents. With this improved method, it was possible to determine the residual sulphites in frozen peeled shrimps, sugared beans and other foods with low sulphite contents accurately.

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Colorimetrische Mikrobestimmung von Sulfiten in Lebensmitteln bei Anwendung der modifizierten IV. Rankine Apparatur

Zusammenfassung Geringe Sulfitmengen in Lebensmitteln (geschälte Garnelen, gezuckerte Bohnen) können colorimetrisch bestimmt werden. Die neuentwickelte Methode beruht auf einer Kombination von colorimetrischer Bestimmung mittels p-Rosanilin und der Bestimmungsmethode nach Rankine. Auf diese Weise lassen sich Gehalte von 2 g noch genau bestimmen. Bei der Farbentwicklung wurde das giftige Quecksilbertetrachlorid durch 0.1 n-NaOH ersetzt, anstelle von Luft Stickstoff als Trägergas verwendet und somit eine Oxydation des Sulfits während der Bestimmung vermieden. Da Nitrit und Aldehyde die Farbentwicklung stören, wurde ihr Einfluß durch Dimedon und Natriumazid ausgeschaltet.

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Studies on the Analyses of Sulphites in Foods (IV)     

Design and fabrication of a length-extensional mode rectangular X-cut quartz resonator with zero temperature coefficient.

Rectangular X-cut quartz crystal resonators with cut angles theta > 5.0 degrees and aspect ratios Rzy (= width 2z0/length 2y0) from 0.3 to 0.5 are investigated. The resonators oscillate mode is a length-extensional mode. A semiempirical frequency equation was derived from the stress expressed in terms of the trigonometric and the hyperbolic transcendental functions with constants estimated by the regression curve fit to the stress simulated by the finite-element method (FEM). Contours on which a point satisfies a zero first order temperature coefficient condition are shown in a cut angle theta and Rzy diagram. We proved that a fabricated resonator with Rzy = 0.400 and theta = 16.0 degrees, whose design parameter is located in the area of the contour, had a zero temperature coefficient.     

Plan for first phase of safety demonstration tests of the High Temperature Engineering Test Reactor (HTTR)

Safety demonstration tests using the High Temperature Engineering Test Reactor (HTTR) will be conducted for the purpose of demonstrating inherent safety features of High Temperature Gas-cooled Reactors (HTGRs) as well as providing the core and plant transient data for validation of HTGR safety analysis codes. The first phase safety demonstration test items include the reactivity insertion test and the coolant flow reduction test. In the reactivity insertion test, which is the control rod withdrawal test, one pair out of 16 pairs of control rods is withdrawn, simulating a reactivity insertion event. The coolant flow reduction test consists of the partial loss of coolant flow test and the gas circulators trip test. In the partial loss of coolant flow test, primary coolant flow rate is slightly reduced by control system. In the gas circulators trip test one and two out of three gas circulators are run down, simulating coolant flow reduction events. The gas circulators trip tests, in which position of control rods are kept unchanged, are simulation tests of anticipated transients without scram (ATWS).     

Identification of charge‐transfer transition between Gd3+ to O2− in gadolinium‐containing oxide phosphors in VUV region

Abstract— The broad bands at around 155 nm for GdAl₃(BO₃)₄:Eu, at 184 nm for Ca₄GdO(BO₃)₃:Eu, at 183 nm for Gd₂SiO₅:Eu, and at 170 nm for GdAlO₃:Eu were observed. These bands were assigned to the charge‐transfer (CT) transition of Gd³⁺‐O^2?. In the excitation spectrum of (Gd,Y)BO₃:Eu, a broadened excitation band was observed in VUV region. It could be considered that this band was composed of two bands at about 160 and 166 nm. The preceding band was assigned to the BO₃ group absorption. The later one at about 166 nm could be assigned to the CT transition of Gd³⁺‐O^2?, according to the result of GdAl₃(BO₃)₄:Eu, Ca₄GdO(BO₃)₃:Eu, Gd₂SiO₅:Eu, and GdAlO₃:Eu. The excitation spectra overlapped between the CT transition of Gd³⁺‐O^2? and BO₃ groups absorption. It caused the emission of Eu³⁺ to take place effectively in the trivalent europium‐doped (Gd,Y)BO₃ host lattice under 147‐nm excitation.     

Gain and phase margin of optimal memoryless regulator of systems with time-delay

A class of linear quadratic regulators of the system with time-delay in the states is constructed by a memoryless feedback, and its robustness is evaluated. First, a static non-linear perturbation is inserted in the input channel, and a robust stability condition is derived. As its special case, it is shown that the regulator has infinite gain margin and at least 50% gain reduction tolerance. Next, a dynamic linear perturbation is inserted in the same point, and an alternative stability condition is derived. It assures that the regulator has at least 60o phase margin. These results coincide with those of the finite dimensional LQ regulator.