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21.
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The inhomogeneous distribution of excess or deficient silver atoms lies behind the large and linear transverse magnetoresistance displayed by Ag2+/-delta Se and Ag2+/-delta, introducing spatial conductivity fluctuations with length scales independent of the cyclotron radius. We report a negative, nonsaturating longitudinal magnetoresistance up to at least 60 T, which becomes most negative where the bands cross and the effect of conductivity fluctuations is most acute. Thinning samples down to 10 microm suppresses the negative response, revealing the essential length scale in the problem and paving the way for designer magnetoresistive devices. 相似文献
23.
Back BB Baker MD Ballintijn M Barton DS Betts RR Bickley AA Bindel R Busza W Carroll A Chai Z Decowski MP García E Gburek T George N Gulbrandsen K Halliwell C Hamblen J Hauer M Henderson C Hofman DJ Hollis RS Hołyński R Holzman B Iordanova A Johnson E Kane JL Khan N Kulinich P Kuo CM Lin WT Manly S Mignerey AC Nouicer R Olszewski A Pak R Reed C Roland C Roland G Sagerer J Seals H Sedykh I Smith CE Stankiewicz MA Steinberg P Stephans GS Sukhanov A Tonjes MB Trzupek A Vale C van Nieuwenhuizen GJ 《Physical review letters》2005,94(8):082304
We have measured transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt[s(NN)]=62.4 GeV. The spectra are presented for transverse momenta 0.25
相似文献
24.
No Heading Quantum mechanics and general relativity share an equivalence with respect to the holographic principle. Large-scale fluctuations predicted by the holographic principle may be derived from the quantum mechanics of spin. As holographic theories, quantum mechanics and general relativity in quaternionic bases are formally similar. Gravitation may not be properly quantized and unified with quantum fields in the usual manner, but rather gravitation and Dirac quantum fields as two separate spinor fields that form pairs which define octonions. 相似文献
25.
Betts TJ 《Journal of chromatographic science》2000,38(8):357-364
The boiling points (degrees C, 1 x 10) of diverse C10 polar solutes from volatile oils are set against their relative retention times versus n-undecane to calculate linear equations for 12 commercial modified cyclodextrin (CD) capillary phases. Ten data points are considered for each CD, then solutes are rejected until 5 or more remain that give an expression with a correlation coefficient of at least 0.990 and a standard deviation of less than 5.5. Three phases give almost perfect correlation, and 3 other CDs have difficulty complying. Solutes involved in the equations (most frequently cuminal, linalol, and carvone) are presumed to have a 'standard' polar transient interaction with the molecular rings of the CDs concerned. Several remaining solutes (mostly citral, fenchone, and menthol) exhibit extra retention over the calculated standard (up to 772%), which is believed to indicate a firm 'host' CD or 'guest' solute molecular fit in some cases. Other solutes show less retention than calculated (mostly citronellal, citronellol, estragole, and pulegone). This suggests rejection by the CD, which behaves merely as a conventional stationary phase to them. The intercept constant in the equation for each phase is suggested to be a numerical relative polarity indicator. These b values indicate that 3 hydroxypropyl CDs show the most polarity with values from 28 to 43; and CDs that are fully substituted with inert groups fall in the range of 15 to 20. 相似文献
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27.
R.R. Betts C. Gaarde Ole Hansen J.S. Larsen S.Y. Van Der Werf 《Nuclear Physics A》1975,253(2):380-394
The 41Ca(d, t)40Ca and 41Ca(d, τ)40K reactions have been investigated at a bombarding energy of 40 MeV. A distorted-wave analysis of the measured angular distributions and a sum-rule analysis of the resulting spectroscopic factors has enabled the identification of members of various particle-hole multiplets. Values obtained for the matrix elements of the effective interaction are in poor agreement with values obtained from other nuclei, but are reasonably well reproduced by calculations with a simple force. 相似文献
28.
J. T. Betts 《Journal of Optimization Theory and Applications》1975,16(1-2):1-24
An effective algorithm is described for solving the general constrained parameter optimization problem. The method is quasi-second-order and requires only function and gradient information. An exterior point penalty function method is used to transform the constrained problem into a sequence of unconstrained problems. The penalty weightr is chosen as a function of the pointx such that the sequence of optimization problems is computationally easy. A rank-one optimization algorithm is developed that takes advantage of the special properties of the augmented performance index. The optimization algorithm accounts for the usual difficulties associated with discontinuous second derivatives of the augmented index. Finite convergence is exhibited for a quadratic performance index with linear constraints; accelerated convergence is demonstrated for nonquadratic indices and nonlinear constraints. A computer program has been written to implement the algorithm and its performance is illustrated in fourteen test problems. 相似文献
29.
Back BB Baker MD Barton DS Betts RR Bindel R Budzanowski A Busza W Carroll A Decowski MP Garcia E George N Gulbrandsen K Gushue S Halliwell C Heintzelman GA Henderson C Hofman DJ Hołyński R Holzman B Johnson E Kane JL Katzy J Khan N Kucewicz W Kulinich P Lin WT Manly S McLeod D Michałowski J Mignerey AC Mülmenstädt J Nouicer R Olszewski A Pak R Park IC Pernegger H Reed C Remsberg LP Reuter M Roland C Roland G Rosenberg L Sarin P Sawicki P Skulski W Steadman SG Steinberg P Stephans GS 《Physical review letters》2001,87(10):102303
The charged-particle pseudorapidity density dN(ch)/d eta has been measured for Au+Au collisions at sqrt[s(NN)] = 130 GeV at RHIC, using the PHOBOS apparatus. The total number of charged particles produced for the 3% most-central Au+Au collisions for /eta/相似文献
30.
N. J. Stone S. Ohya J. Rikovska A. Woehr P. Betts J. Dupak B. Fogelberg L. Jacobsson 《Hyperfine Interactions》2001,133(1-4):111-115
The nuclear spin–lattice relaxation of 127In implanted into pure gadolinium metal has been measured using the method of integral attenuation of on-line nuclear orientation. The Korringa constant is determined to be CK (127InGd, Bpol = 0.5 T) = 0.133(18) sK. The result is compared with relaxation of In nuclei inFe. 相似文献