Showing papers by "Shandong University published in 1985"

Measurement of electromagnetic shower position and size with a saturated avalanche tube hodoscope and a fine grained scintillation hodoscope

Abstract: A hodoscope has been constructed from 100 μm diameter wires and brass tubes (1.2 × 0.7 cm2 cross section) filled with a mixture of argon, ethane and ethyl alcohol. It has been tested in the saturated avalanche mode in an SCG1-C electromagnetic shower detector to determine its properties for the measurement of the position and size of electromagnetic showers. Two of these tube hodoscopes were positioned 3.5 radiation lengths deep in the detector and the profiles of 1–25 GeV electromagnetic showers were measured. Simultaneous measurements were performed using a plane of twenty, 0.5 cm wide scintillation counters positioned immediately behind the gas tube hodoscope. In addition the transition between saturated avalanche and limited streamer modes was observed for the tube hodoscopes.

Design Principle For Simultaneous Emissivity And Temperature Measurements

Abstract: One of the critical questions regarding radiation thermometers is how to obtain the true temperature of an emitting greybody with an unknown emissivity and with unknown circumferential radiations. In this paper it is suggested that two enclosed chambers with given temperatures and emissivities be used to cover part of the area of the greybody. By using two simultaneous radiothermometer readings, both the true temperature and the emissivity of the greybody can be calculated.

Novel approximations to 0 Σ ∞ |h(n)| for second order digital filters

Abstract: The expression \Sigma\min{0}\max{\infin}|h(n)| is often encountered in literature or text books where the limit-cycle bounds for digital filters or l 1 norm for impulse responce sequence {h(n)} is used. Several authors have tried and derived some useful upper bounds for direct form digital filters mathematically ( 1,2,3 ). In this paper, novel approximations to the sum for direct form and normal form digital filters will be given, with the only constant factor \pi/4 appeared. Plots for an example are given for comparison.

Continuum dimuon production in p-bar-W collisions at 125 GeV/c.

Abstract: The cross section for the reaction p-barN..--> mu../sup +/..mu../sup -/X with muon pairs in the mass range 40 was measured to be sigma = 0.104 +- 0.005 +- 0.008 nb/nucleon. The distributions dsigma/dx/sub F/ and M/sup 3/dsigma/dM were compared to the QCD-improved Drell-Yan model and to calculations including first-order QCD corrections using deep-inelastic structure functions. Excellent agreement with the data was obtained if the calculations were multiplied by factors of 2.45 and 1.41, respectively.

A hydrogen-related complex defect model in a-Si:H

Abstract: The electronic energies were calculated for a model of hydrogen-related complex defects in a-Si:H, which has Td symmetry, being a hybride quartet. Using the complete neglect of differential overlap CNDO method, we find the probability of the formation of the hybride quartet in a-Si:H. It is concluded that the hybride quartet is a plausible complex model of hydrogen-related defects in a-Si:H than the hydrogenated vacancy with four SiH bonds unrelated one another.

A study on the adsorption voltammetry of cobalt(II)—dime thylglyoxime system

Abstract: The behaviour of the cobalt complex with dimethylglyoxime (DMG), Co(II)A2, at the mercury electrode has been investigated in details. The adsorption phenomena have been observed by both normal pulse polarography and voltammetry with linearly changing potential. Experimental results show that, under the condition of adsorption potentials ranging from −0.60 to −0.9 eV (vs. S.C.E.), Co(II)A2 can be adsorbed on the surface of hanging mercury drop electrode (HMDE) very well. The superficial concentrations represents a Langmuir isotherm with both concentration of Co(II)A2 and the preconcentration time. The superficial concentration equation for adsorption voltammetry, corresponding to the condition of the low coverage of the electrode surface, is deduced. The equation has been verified experimentally. The sensitivity of the proposed method, which has been analysed theoretically, is independent on the scan rate and the surface area of HMDE, but depends on the preconcentration time and the diffusion layer thickness. For the 120 sec accumulation, the lower limit of determination is 1.10−9 M.

Topological computation of indefinite matrix

Abstract: A digraph associated with an indefinite matrix is augmented. Both the first-order and second-order cofactors can be obtained by finding all the directed trees in the augmented digraph and eliminating the need of computing the directed 2-trees for the second-order cofactors. The technique proposed here is particularly applicable to computer-programming.

Proper solutions and limit boundary value problems of nonlinear second-oroer systems of differential equations

Abstract: For the system of differential equations (fx1113-1) where a(t) > 0, r(t) > 0 for t ≥ t0; f(x) > 0 and is decreasing for x > 0, g(y) > 0, we give necessary and sufficient condition of the existence of a proper solution, a bounded proper solution or solutions of two kinds of boundary value problems on an infinite interval [c, ∞) c ≥ t0. Several examples are given to illustrate the conditions of these results.

A matched filter using charge coupled device for pulse-code modulation

Abstract: A matched filter using CCD for PCM is made. The experimental results of output waveform, transfer function and output signal-to-noise ratio are given and compared with the theoretical ones. The output signal-to-noise ratio for the non-return-to-zero codes is 1 dB below the theoretical value.