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61.
An error analysis of the use of photoelasticity in the study of fracture problems is attempted. In particular, it was desired to determine the optimum regions of data collection and to ascertain the sensitivity of the extractedK 1 andK 2 values to errors in such parameters as crack-tip position and fringe location. Experiments were performed on both Mode 1 and Mixed Mode cases and the results compared with the error analysis 相似文献
62.
63.
A. T. Britton J. L. Sullivan K. J. Smith 《Journal of Polymer Science.Polymer Physics》1979,17(8):1281-1293
Using thermoelastic measurements, specific polymer-diluent interactions have been demonstrated for atactic poly(vinyl alcohol) networks swollen in water. This was done by following a thermodynamic parameter as a function of network swelling, which was controlled by varying the extent of network crosslinking. At low crosslinking (high swelling) the ratio of the energy component fe of the force to the total force f was found to be perhaps a little less than ?0.38 for poly(vinyl alcohol) swollen in water to less than 0.36 volume fraction of polymer. The method of evaluation is new and should be applicable to other polymer single component diluent systems. 相似文献
64.
An analysis of the crystal environments of sulfonium ions shows that short nonbonded contacts (secondary bonds) to sulfur tend to occur along the extensions of the C-S primary bonds. Non-bonded contacts to the C (a)-atoms of sulfonium ions are not especially short and do not show any striking directional preference, except in sulfonium ions derived from methionine where a specific intramolecular interaction between a carboxyl O-atom and the C (γ)-atom may represent an incipient stage of the internal nucleophilic displacement leading to formation of homoserine and mercaptan. 相似文献
65.
Generally, companies selling overseas do not select foreign markets systematically. This paper introduces the concepts of a market concentration strategy and an optimum portfolio of markets as a basis for planning foreign markets. It is shown how numerical classification procedures can operationalize these strategy concepts. Wishart's mode analysis is illustrated as an effective tool for solving this problem. 相似文献
66.
T.?SchaetzEmail author D.?Leibfried J.?Chiaverini M.D.?Barrett J.?Britton B.?DeMarco W.M.?Itano J.D.?Jost C.?Langer D.J.?Wineland 《Applied physics. B, Lasers and optics》2004,79(8):979-986
We describe the concept and experimental demonstration of the basic building blocks of a scalable quantum computer using trapped-ion qubits. The trap structure is divided into subregions where ion qubits can either be held as memory or subjected to individual rotations and multi-qubit gates in processor zones. Thus, ion qubits can become entangled in one trapping zone, then separated and distributed to separate zones (by switching control-electrode potentials) where subsequent single- and two-ion gates, and/or detection is performed. Recent work using these building blocks includes (1) demonstration of a dense-coding protocol, (2) demonstration of enhanced qubit-detection efficiency using quantum logic, (3) generation of GHZ states and their application to enhanced precision in spectroscopy, and (4) the realization of teleportation with atomic qubits. In the final section an analog quantum computer that could provide a shortcut towards quantum simulations under requirements less demanding than those for a universal quantum computer is also described. PACS 03.67.Lx; 32.80.Qk 相似文献
67.
Doyle AW Fick J Himmelhaus M Eck W Graziani I Prudovsky I Grunze M Maciag T Neivandt DJ 《Langmuir : the ACS journal of surfaces and colloids》2004,20(21):8961-8965
Structural deformations of lipid hybrid bilayer membranes induced by signal peptideless (SPL) proteins have been studied for the first time using the inherently surface specific nonlinear optical technique of sum frequency generation vibrational spectroscopy. Specifically, deformations of 1,2-distearoylphosphatidylglycerol(DSPG) membranes induced by interaction with FGF-1, a SPL protein which is released asa function of cellular stress through a nonclassical pathway, have been investigated. FGF-1 was found to induce lipid alkyl chain deformations in previously highly ordered DSPG membranes at the extremely low concentration of 1 nM at 60 degrees C. The deformation process was shown to exhibit a degree of reversibility upon removal of the protein by rinsing with buffer solution. 相似文献
68.
Ben-Kish A DeMarco B Meyer V Rowe M Britton J Itano WM Jelenković BM Langer C Leibfried D Rosenband T Wineland DJ 《Physical review letters》2003,90(3):037902
Using a single, harmonically trapped 9Be(+) ion, we experimentally demonstrate a technique for generation of arbitrary states of a two-level particle confined by a harmonic potential. Rather than engineering a single Hamiltonian that evolves the system to a desired final state, we implement a technique that applies a sequence of simple operations to synthesize the state. 相似文献
69.
The crystal structure of 2,6-di(Pr(i))aniline hydrochloride contains hydrogen-bonded cubanes analogous to those in the complexes [M(2+)(2,6-di(Pr(i))C6H5N(2-))]4, M = Sn, Pb. 相似文献
70.