Cellulose-based fibers from liquid–crystalline solutions. II. Processing and morphology of acetate/butyrate esters

Fibers were spun from isotropic and anisotropic dimethylacetamide solutions of cellulose esters. Take-up speeds of the dry jet/wet spinning process varied. Water served as the coagulant. The mechanical properties of the fibers increased as spinning progressed from the isotropic to the anisotropic state of the solution. A trade-off in solubility and fiber properties was noted as the butyryl acetyl ratio decreased. Whereas high butyryl content enhances both overall solubility and the formation of liquid–crystalline solutions at lower concentration, it results in lower fiber modulus and strength. Morphology of the fibers depended on the coagulation rate which was influenced by the concentration of the sppinning solution. The level of orientation and crystallinity of the fibers increased somewhat when they were spun from liquid-crystalline solutions. © 1993 John Wiley & Sons, Inc.     

Ring resonators with N × M couplers

Multiple-zero multiple-pole optical filter transfer functions may be implemented more efficiently in an integrated optics architecture if higher order N × M optical couplers are utilized. For example, a coherent ring resonator made from two 3×3 couplers offers some advantages over the three mirror Fabry-Perot etalon, which is its analog. To this end we develop the formalism for obtaining the transfer functions and scattering matrices of ring resonators made from two N × M couplers. We then present a methodology for analyzing serial and parallel systems of N × M optical coupler ring resonators.     

A nonlocal Hamiltonian formalism for semi-Hamiltonian systems of the hydrodynamic type

A nonlocal Hamiltonian formalism for semi-Hamiltonian systems of the hydrodynamic type is constructed using the formal Baker-Akhiezer functions for a (2+1)-dimensionaln-wave system. Translated from Teoreticheskaya i Matematicheskaya Fizika. Vol. 116, No. 1, pp. 113–121 July, 1998.     

Parametric study of high energy plasmas for electrothermal-chemicalpropulsion applications

Theoretical calculations are performed with a one-dimensional (1-D), steady state, isothermal computer plasma model to define plasma output parameters for various input electrical energies and capillary radii of relevance to the electrothermal-chemical (ETC) propulsion concept. Three capillaries of 1.92, 4.75, and 7.0 mm radius, and a fixed length of 11.84 cm, were chosen for this study with input currents between 30 and 350 kA. Plasmas are categorized according to their total power and energy levels (based on a 3-ms pulse width) and are compared with respect to their resistance, exit pressure, and core plasma temperature. The input power ranges from 0.17 to 1.89 GW, for input energies from 0.49 to 5.80 MJ, which is considered suitable coverage for ETC ignition through ETC enhanced propulsion concepts. The study shows that the range of resistance, pressure, and temperature are 12.8-195 mΩ, 19.8-2000 MPa, and 2.9-13.5 eV, respectively, for the chosen capillary geometry. Flow conditions for plasma calculations include choked (no pressure boundary) and unchoked (450-MPa pressure boundary) for some calculations. Results from the computational model and interpretations from the perspective of capillary implementation into ETC propulsion concepts are also included     

Time‐integrated energy domain measurements with synchrotron radiation

A new time integrated method for the study of resonant nuclear scattering of synchrotron radiation in the forward direction or in Bragg directions is introduced. This method gives in principle similar information as the well known time differential method. A brief comparison of both methods is presented. The idea is to excite coherently the nuclei incorporated in two absorbers, one moving with respect to the other. The fields radiated by the nuclei from both absorbers interfere and each time the nuclear energy in one absorber matches, by Doppler modulation, the nuclear energy of the other, an extremum in the time integrated intensity is observed. The results of the first experiments at the Advanced Photon Source at the Argonne National Laboratory will be presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Ferromagnetic resonance in multilayer [Fe/Cr]n structures with noncollinear magnetic ordering

The excitation spectrum in an [Fe/Cr]n multilayer structure with non-collinear magnetic ordering was studied by the ferromagnetic resonance (FMR) method in the frequency interval 9.5–37 GHz at room temperature. Besides an acoustic branch, several additional modes were observed under parallel excitation of resonance. The FMR spectrum was calculated analytically in a biquadratic exchange model, neglecting in-plane anisotropy, for an infinite number of layers in the structure and numerically for a finite number of layers contained in real samples. It was shown that the observed modes correspond to excitation of standing spin waves with wave vectors perpendicular to the film plane. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 9, 690–695 (10 May 1998)     

SINGLE MACHINE SCHEDULING WITH CONTROLLABLE PROCESSING TIMES AND COMPRESSION COSTS （PART I：EQUAL TIMES AND COSTS）

Most papers in scheduling research have treated individual job processing times as fixed parameters. However, in many practical situations, a manager may control processing time by realloeating resources. In this paper, authors consider a machine scheduling problemwith controllable processing times. In the first part of this paper, a special case where the pro-cessing times and compression costs are uniform among jobs is discussed. Theoretical results are derived that aid in developing an O（n^2) algorithm to slove the problem optimally. In the second part of this paper, authors generalize the discussion to general case, An effective heuristic to the genera/ problem will be presented.     

Nuclear fusion in the mesic molecule d μ 3He

A new scheme is presented for the physical processes leading to the nuclear fusion reaction d(³He, ⁴He)p catalyzed by a negatively charged muon μ⁻. It is shown that the observable rate and yield of the nuclear reaction depend on a chain of ion-molecular reactions involving the participation of the dμ ³He molecule. New calculations of the nuclear fusion rates in the dμ³He molecule are presented. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 2, 89–94 (25 January 1998) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Chaotic Maps, Control Parameter, and Liapunov Exponent

We describe a one-dimensional chaotic map wherethe Liapunov exponent is a smooth function of a controlparameter.