Showing papers on "Crossover published in 1980"

The crossover experiment for clinical trials.

Abstract: The two-period crossover or changeover design for clinical trials is compared with other simple designs in terms of statistical precision and cost. The sensitivity of the crossover to bias due to carryover effects is examined. The feasibility of using the crossover data to test for the existence of carryover effects is investigated and found to be uneconomical. A numerical example is presented.

Crossover from percolation to random animals and compact clusters

Abstract: Introduces a field-like variable to develop a generating function for the percolation problem which, in the appropriate limits, also describes the statistics of random animals (dilute branched polymers) and compact clusters (collapsed branched polymers). The crossover from percolation to random animals and compact clusters is studied using a two-parameter position space renormalisation-group approach. The authors obtain the global flow diagram in the two-parameter space and calculate the critical properties. They find that the critical behaviour is described below the percolation threshold pc by the random-animal fixed point, and above pc by the compact-cluster fixed point. A Hamiltonian formulation using the Q-state Potts model is proposed. The crossover from percolation to random animals can be described by taking a specific limit of the field-like variable.

Specific heat near the lambda point in 4He and 3He-4He mixtures: Test of universality of the critical exponent and the amplitude ratio, and observation of the critical-tricritical crossover effect

Abstract: The specific heat under saturated vapor pressure of pure 4He and of six 3He-4He mixtures up to X = 0.545 was measured in the temperature range 3 × 10−6 <¦T-T λ¦ <10−2 K. The critical exponents αΦ and α′Φ along the path Φ = Φλ are independent of X up to X = 0.545, where Φ (= Μ3 − Μ4) is the difference between chemical potentials. If we take account of higher order terms, the exponent αΦ (= α′Φ) and the amplitude ratio A Φ/A′Φ are independent of X up to X = 0.545. The values of αΦ and A Φ/A′Φ are −0.023 and 1.090, respectively. The critical-tricritical crossover effect was observed for X = 0.545 and the boundary of crossover region closest to the critical region was at θ/T λ = (1−2) × 10−4, where θ is the distance ¦T − T λ ¦ along the path Φ = Φ λ . This value is in good agreement with the estimated value by Riedel et al. But, remarkably, in the case of X = 0.439 this effect was not observed.

Matched pairs in factorial experiments with binary data

Abstract: Two more models are proposed for the analysis of matched pairs in factorial experiments with binary data. They are applied to two-period crossover designs. Estimation and test procedures are derived both approximately and by maximizing likelihoods. Comparisons are made with previous methods of analysis and between the models proposed.

Differential linear to digital translator

Abstract: An improved linear to digital translator having parallel current paths with unequal resistances. The resistances are sized according to a determined relationship between circuit parameters to improve crossover performance. In addition, non-saturating devices are used to reduce delay times.

Numerical calculations of crossover effects in rare-earth zircons

Abstract: The Hamiltonian used to describe Jahn-Teller compounds like DyVO4, TbVO4, TmVO4, TbAsO4, etc., has a non-analytic term arising from the coupling of the lattice displacements to the pseudo-spins. One explicitly calculates the angular dependence of this term, for both types of distortion involved. The values of the elastic constants are used to obtain numerical values of the quantities that prove relevant for a study of the associated crossover effects. A simple approximation to the form of the interaction is used; the effective exponent gamma eff is then evaluated as a function of the temperature, within an epsilon -expansion calculation. The corrections introduced when the exact form of the interaction is considered do not significantly change the crossover behaviour. The critical behaviour expected of compounds that suffer a B1g distortion (DyVO4) and the ones undergoing a B2g distortion (TbVO4, etc.) is discussed in terms of the differences of the respective values of h(0).

Scaling theory for field-induced crossover in easy-plane magnetic chain systems

Abstract: A scaling treatment is given for field-induced crossover in the correlation lengths of easy-plane magnetic chain systems at low temperature Scaling forms are derived for the cases of ferromagnetic and antiferromagnetic coupling

Effects of capacitance at crossover wirings in power GaAs m.e.s.f.e.t.s.

Abstract: Power GaAs f.e.t.s. with an air-bridge crossover were compared with those of SiO2 crossover to find the effect of the capacitance at the crossover points. The capacitance of SiO2 crossover points is much smaller than that of the gate pad or the gate busbar in power GaAs f.e.t.s, and deterioration of the microwave performance due to that capacitance is negligible.

Dipolar crossover of the two-spin correlation function

Abstract: Renormalisation group recursion relations and matching techniques are used to evaluate to O( epsilon ) the crossover scaling function describing the competition between isotropic short-range and dipolar critical behaviours in the two-point correlation function of a magnetic system above Tc in zero field. The scaling function, obtained in closed form, interpolates between the small-q (q xi >1) limits where asymptotic expressions are written. The results for the effective critical exponents are compared with neutron scattering measurements.

Serial-section analysis of clustering within anthers of maize microsporocytes with specific crossovers.

Abstract: The distribution within anthers of maize plants of microsporocytes of differing crossover class was studied by application of the serial-sectioning technique to plants heterozygous for a paracentric inversion. In such material, cells with four-strand double crossovers within the inversion are distinguishable from cells with other classes of crossovers within the inverted region and from cells with no crossovers within the inversion. Evidence was found for coarse clustering of cells with four-strand double crossovers within the inversion and for coarse clustering of cells of other crossover classes (with at least one crossover within the inversion). The local frequencies of these two major categories of crossover cells appeared to vary independently of each other, with regional increases in each occurring at the expense of noncrossover cells. There is also some suggestion that cells with four-strand doubles within the inversion may be clustered independently of other double-crossover classes within the inversion, but these other classes are not directly scorable.

Crossover wire processor of coil winding machine

Abstract: PURPOSE:To minimize the length of a crossover for eliminating its fray, by using a crossover holding hook, hook driving device, spring mechanism for adding tensile strength to the crossover, hook lock and hook turning device. CONSTITUTION:A cylinder 25 advances a block 22 as winding round a reel 2 is over, and a hook 11 is thrown over the crossover wire 1. A lock pin 18 is engaged with the hook 11 to keep a spring 12 straight. The block 22 is then moved back and the reel 3 is moved back and forth to turn a flyer 6 for winding. The lock pin 18 is disengaged with the hook 11 before the crossover is stretched and the spring 12 is bent as the crossover is stretched. The winding progresses, therefore, while stretching the crossover to some extent. Then the hook 11 is turned 180 deg. to release it from the crossover. This system can minimize the length of crossover.

Observing method for crossover image of electron gun

Abstract: PURPOSE:To easily observe a crossover image by scanning a focussed crossover image with a diaphram plate, detecting the electron beams passing through the diaphragm hole, and guiding them to a display unit CONSTITUTION:A crossover image is enlarged and focussed on the diaphragm plate 6 with the convergent lens 3 By supplying scanning signals to the deflection coils 12a and 12b in this state, the enlarged crossover image is two-dimensionally scanned at the diaphragm hole 6a Also by the reflected electron beams E which correspond to the intensity of the electron beams passing through the diaphragm hole 6a with the detector 14, the brightness modulation of the cathode ray tube 16 is performed and the crossover image is displayed

Thick-film circuit device

Abstract: A thick-film circuit device having a substrate of insulating material containing alkali components, a first crossover made of non-alkali type glass and formed on the substrate, wiring conductors formed on the first crossover according to a predetermined circuit pattern, and a second crossover made of glass and formed on the first crossover so that it covers the wiring conductors, the first crossover preventing entry of sodium ions into the second crossover.

Spannungsinduzierte Crossover-Effekte in der Nähe des Curiepunkts von nickel: I. Experimentelles und Meßergebnisse

Abstract: Stress-induced crossover effect near the Curie point of nickel I. Experimental details and results In a small angle neutron scattering experiment stress-induced crossover in a ferromagnetic nickel ...