A symmetric on-demand beam deflector for use in conjunction with particle microbeams is described. Tests of the device in a micro-PIXE system with a 3 μm width beam indicate that the position and dimensions of the mi...
A symmetric on-demand beam deflector for use in conjunction with particle microbeams is described. Tests of the device in a micro-PIXE system with a 3 μm width beam indicate that the position and dimensions of the microbeam are not significantly altered. Measurement of beam charge is accomplished either by conventional integration or by recording RBS spectra from vanes rotating through the beam; careful attention to dead time is necessary in the latter case. In micro-PIXE reduction of specimen damage by the beam deflector is of considerable value.
Raman and infrared spectra of solid chlorotrifluoromethane have been recorded in both the internal and lattice mode regions at temperatures between 20 K and its melting point. The spectra are compared to the predictio...
Raman and infrared spectra of solid chlorotrifluoromethane have been recorded in both the internal and lattice mode regions at temperatures between 20 K and its melting point. The spectra are compared to the predictions of a group theoretical analysis based on the known molecular and unit cell symmetries. The absence of a centre of inversion is confirmed. Plausible assignments of all main spectroscopic features are presented.
The Raman and infrared spectra between 30 and 3000 cm −1 of a new crystalline phase of methyltrichlorosilane, CH 3 SiCl 3 , at 20 K are reported. The spectra are consistent with a non-centrosymmetric crystal structure...
The Raman and infrared spectra between 30 and 3000 cm −1 of a new crystalline phase of methyltrichlorosilane, CH 3 SiCl 3 , at 20 K are reported. The spectra are consistent with a non-centrosymmetric crystal structure with at least four molecules per unit cell. A glassy phase is also detected.
This paper presents the results of a study of the anodic oxidation of n‐type AlGaAs and AlGaAs/GaAs heterojunctions in acid‐glycol‐water electrolytes. Anodic oxides with thickness up to 300 nm may easily be grown u...
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This paper presents the results of a study of the anodic oxidation of n‐type AlGaAs and AlGaAs/GaAs heterojunctions in acid‐glycol‐water electrolytes. Anodic oxides with thickness up to 300 nm may easily be grown under constant‐current conditions if external illumination is used. Real‐time derivative spectra of the anodic voltage‐time data show structure that is dependent upon the thickness of the AlGaAs epitaxial layer, its doping density, and possibly band‐gap energy differences. The derivative results clearly show that epitaxial layer thickness and thickness variations are readily measured. The oxide growth constant and material consumption rate are found to be 1.52 and 1.08 nm/V, respectively. Optical dispersion in the wavelength range from the near UV to the IR range is also measured and fitted to Sellmeier’s equation. Composition of the AlGaAs is measured using Rutherford backscattering, which reveals an As‐rich oxide.
We have calculated the pseudoscalar decay constants using the relativized quark model. We find fD≃240±20 MeV, fDs≃290±20 MeV, fB≃155±15 MeV, fBs≃210±20 MeV, and fBc≃410±40 MeV where the "...
We have calculated the pseudoscalar decay constants using the relativized quark model. We find fD≃240±20 MeV, fDs≃290±20 MeV, fB≃155±15 MeV, fBs≃210±20 MeV, and fBc≃410±40 MeV where the "errors" are our estimates of the reliability of the results. We used these values to study the Cabibbo-Kobayashi-Maskawa matrix elements. In particular, we combined our theoretical estimate of fB with the ARGUS/CLEO result for B0−B¯0 mixing to study the relation between |Vtd| and the t-quark mass. Recent measurements of |Vbc| and |Vbu| constrain mt≳70 GeV.
A three-dimensional lattice model for surfactant mixtures is presented in this paper. We extend the spin-1 or Blume-Emery-Griffiths model to include orientational degrees of freedom for each molecule. The model is the...
A three-dimensional lattice model for surfactant mixtures is presented in this paper. We extend the spin-1 or Blume-Emery-Griffiths model to include orientational degrees of freedom for each molecule. The model is then applied to ternary mixtures of surfactant with equal amounts of water and oil, and to binary mixtures of surfactant and water. For each case, phase diagrams are calculated using both mean-field and Bethe approximations. One interesting feature of this model is that it can exhibit long-period lamellar phases even though a simple Hamiltonian, containing only nearest-neighbor interactions, is used. The model also produces a ‘‘disorder line,’’ which is thought to divide the disordered phase of the ternary mixture into a region of ordinary disordered fluid and a region of microemulsion.
In this paper a review is given of recnet work in IR and Raman spectroscopy of the solid hydrogens. The main aim is to help the reader find literature references that are relevant to his or her interests.
In this paper a review is given of recnet work in IR and Raman spectroscopy of the solid hydrogens. The main aim is to help the reader find literature references that are relevant to his or her interests.
Two closely coupled superconducting microbridges have been fabricated with the length of the separating superconducting region less than a coherence length. These microbridges exhibit coupling even when there is zero ...
Two closely coupled superconducting microbridges have been fabricated with the length of the separating superconducting region less than a coherence length. These microbridges exhibit coupling even when there is zero bias potential at each microbridge. The critical current of each microbridge is a function of the bias current of the other microbridge. This type of coupling is explained by a coupling current that is proportional to the sine of the sum of the phases of both microbridges.
Herein, it is shown that by exploiting integral definitions of well known special functions, through generalizations and differentiations, broad classes of definite integrals can be solved in closed form or in terms o...
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It is shown that Symbolic Computation provides excellent tools for solving quantum mechanical problems by perturbation theory. The method presented herein solves for both the eigenfunctions and eigenenergies as power ...
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It is shown that Symbolic Computation provides excellent tools for solving quantum mechanical problems by perturbation theory. The method presented herein solves for both the eigenfunctions and eigenenergies as power series in the order parameter where each coefficient of the perturbation series is obtained in closed form. The algorithms are expressed in the Maple symbolic computation system but can be implemented on other systems. This approach avoids the use of an infinite basis set and some of the complications of degenerate perturbation theory. It is general and can, in principle, be applied to many separable systems.
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