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131.
132.
F.E. Cecil J.R. Shepard R.R. Sercely R.J. Peterson N.S.P. King 《Physics letters. [Part B]》1976,64(4):411-413
We have measured the differential cross sections for the reactions 12C(τ, τ′)12C(17.77 MeV 0+T=1) and 12C(τ, t)12N(2.43 MeV) at Eτ=44 MeV. The similar shapes of the angular distributions and the relative magnitudes of the cross sections suggest that the 12N 2.43 MeV level is the 0+T=1 analog to the q12C 17.77 MeV level. We have also studied the reaction 14N(p,t) 12N(2.43 MeV) at Ep=52 MeV. The strength with which this level is excited in this reaction is consistent with reasonable two-step calculations assuming the 2.43 MeV level to have Jπ=0+. 相似文献
133.
134.
The difference of twoposynomials (namely, polynomials with arbitrary real exponents, but positive coefficients and positive independent variables) is termed asignomial.Each signomial program (in which a signomial is to be either minimized or maximized subject to signomial constraints) is transformed into an equivalent posynomial program in which a posynomial is to be minimized subject only to inequality posynomial constraints. The resulting class of posynomial programs is substantially larger than the class of (prototype)geometric programs (namely, posynomial programs in which a posynomial is to be minimized subject only to upper-bound inequality posynomial constraints). However, much of the (prototype) geometric programming theory is generalized by studying theequilibrium solutions to thereversed geometric programs in this larger class. Actually, some of this theory is new even when specialized to the class of prototype geometric programs. On the other hand, all of it can indirectly, but easily, be applied to the much larger class of well-posedalgebraic programs (namely, programs involving real-valued functions that are generated solely by addition, subtraction, multiplication, division, and the extraction of roots).This research was partially supported by Research Grant No. DA-AROD-31-124-6680 from the Army Research Office, Durham, North Carolina, and by a Summer Fellowship Grant from Northwestern University. 相似文献
135.
We present a detailed ab initio study of the effect that the Born-Oppenheimer diagonal correction (BODC) has on the saddle-point properties of the H3 system and its isotopomers. Benchmark values are presented that are estimated to be within 0.1 cm(-1) of the complete configuration-interaction limit. We consider the basis set and correlation treatment requirements for accurate BODC calculations, and both are observed to be more favorable than for the Born-Oppenheimer energies. The BODC raises the H + H2 barrier height by 0.1532 kcal/mol and slightly narrows the barrier--with the imaginary frequency increasing by approximately 2%. 相似文献
136.
Kenneth S. Pitzer John R. Peterson Leonard F. Silvester 《Journal of solution chemistry》1978,7(1):45-56
The extensive data for the osmotic coefficients, heats of dilution, and densities of aqueous solutions of rare earth chlorides, nitrates, and perchlorates are fitted to a single type of equation found satisfactory for many other solutes Good agreement is obtained. The various parameters do not show simple trends with cation radius. While there are some plausible explanations of these complexities, the total picture is far from clear. 相似文献
137.
138.
The simultaneous diffusion of 55Co and 60Co has been measured in CoO as a function of equilibrium oxygen pressure in the range 10?9 < po2 < 1 atm at 1200°C. The slope of the log D1Co vs logpo2 plot changes from a value of about at high po2 to about at low po2, in agreement with the extensive measurements of Dieckmann. The isotope effect is independent of po2, which suggests that diffusion by defect clusters, interstitial Co ions and impurity-induced defects is not important in the present measurements. Conductivity, diffusion, stoichiometry and isotope-effect results are consistent with diffusion by neutral, singly charged, and doubly charged vacancies; the relative contributions from the various vacancies varies with po2. 相似文献
139.
The simultaneous diffusion of 52Fe and 59Fe has been measured in Fe3O4 as a function of equilibrium oxygen partial pressure (10?9 <po2 < 10?4 atm) at 1200°C. The po2 dependence of D goes through a minimum near 10?6 atm in agreement with earlier data of Dieckmann and Schmalzried. Comparison of the isotope effect results with correlation-factor calculations suggests that at po2 γ 10?6, diffusion occurs predominantly by vacancy jumps between the normally occupied octahedral sites on the spinel lattice; jumps between tetrahedral sites probably play a lesser role. At po2< 10?6 atm, diffusion occurs by an interstitialtype mechanism involving the simultaneous migration of two atoms. Five of the seven interstitialcy jumps considered in our correlation-factor calculations are consistent with the experimental results. 相似文献
140.
H. C. Beachell Jean C. Peterson Buck 《Journal of polymer science. Part A, Polymer chemistry》1969,7(7):1873-1879
A high molecular weight linear polyurethane was prepared by the polyaddition of equimolar amounts of ethylene glycol and methylene bis(4-phenyl isocyanate). Varying amounts of the labile carbamate protons of the polyurethane backbone were substituted by a number of groups of varying length and composition. The resultant grafted or nitrogen-substituted polyurethanes were then studied viscometrically in both polymer solvent and in a polymer solvent—nonsolvent mixture. The configuration of the nitrogen-substituted polyurethane was found to be dependent upon the number and length of pendent branches. 相似文献