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21.
Robert D. Cairns 《Natural Resource Modeling》2019,32(4)
The point‐input, point‐output, plantation forest was first studied by Martin Faustmann in the mid‐19th century. The exploitation of a Faustmannian forest involves decisions concerning investments and receipts over time that are qualitatively different from the smooth, convex flows that are usually studied in the economics of accounting. The simple, well understood analysis of the forest has implications for the concept of income in forestry as well as in other industries that are typified by nonconvex decisions. A forest is a salient example of the importance of discrete, irreversible investment, and of the role of price effects (capital gains) in income accounting and, more fundamentally, of perceptions of the “right prices” in economic analysis. 相似文献
22.
23.
We give a new formula for the winding number of smooth planar curves and show how this can be generalized to curves on closed orientable surfaces. This gives a geometric interpretation of the notion of winding number due to B. Reinhart and D.R.J. Chillingworth. 相似文献
24.
T Cairns K S Chiu E Siegmund M Weber 《Rapid communications in mass spectrometry : RCM》1992,6(7):449-453
Ion-trap chemical-ionization performance has been improved by application of a modified scan function for the rejection of the undesired electron-ionization-like (EI-like) ions formed at the beginning of the reaction ionization period. The net effect of this software modification to the automatic reaction control is to produce chemical ionization (CI) spectra that are no longer adulterated with concentration-dependent EI-like ions. Under such improved conditions, CI spectra from an ion trap can now be directly compared with CI spectra produced on conventional quadrupole and magnet-scanning instruments. 相似文献
25.
A general method tor the preparation of 1,4-dihydro-4-quinolone-2-carboxylic acids, especially those which carry alkyl substituents on the ring N-atom, is described. 相似文献
26.
Elizabeth M. Briggs Geoffrey W. Brown Peter M. Cairns Josef Jiricny Mohamed F. Meidine 《Magnetic resonance in chemistry : MRC》1980,13(4):306-307
31P chemical shifts in N-aryliminotriphenylphosphoranes and the corresponding N-methylated phosphonium salts are presented. They can be correlated with those theories of the bonding in phosphorus-nitrogen ylides which involve partial double bonding as a result of pπ–dπ overlap. 相似文献
27.
28.
The corrosion inhibition of brass in 0.2 M NaCl in the presence of 2-mercaptobenzothiazole (MBT) and polyoxyethylene sorbitan monooleate (Tween-80) has been investigated using potentiodynamic polarization, X-ray photoelectron spectroscopy and inductively coupled plasma analysis. Analysis of the results revealed that the addition of MBT and Tween-80 inhibits the corrosion of brass in 0.2 M NaCl. Potentiodynamic polarization measurements showed that MBT acts as a mixed-type inhibitor and Tween-80 as an anodic inhibitor. Corrosion inhibition occurs through adsorption of the inhibitor on brass surface without modifying the corrosion mechanism. The adsorption of MBT and Tween-80 both follow Langmuir adsorption isotherm. Potentiodynamic polarization results suggested that the mixture of MBT and Tween-80 acts as a mixed-type inhibitor. Inhibition efficiency of 79.0 and 62.5% were obtained in the presence of optimum concentration of MBT and Tween-80, respectively. The addition of the mixture of MBT and Tween-80 enhanced the inhibition efficiency to 94.0% and showed a synergism of inhibition. XPS analysis indicated that MBT adsorbed on brass surface along with Tween-80 in the presence of the mixture of MBT and Tween-80. The results of solution analysis using ICP showed that the mixture of MBT and Tween-80 effectively controlled the dezincification of brass. 相似文献
29.
Grant F. Armstrong Grant Cairns Barry Jessup 《Proceedings of the American Mathematical Society》1997,125(2):381-385
Betti numbers for the Heisenberg Lie algebras were calculated by Santharoubane in his 1983 paper. However few other examples have appeared in the literature. In this note we give the Betti numbers for a family of -dimensional 2-step nilpotent extensions of by .
30.
KM Varier AM Vinodkumar NVSV Prasad PV Madhusudhana Rao DL Sastry Lagy T Baby MC Radhakrishna NG Puttaswamy JJ Das P Sugathan N Madhavan AK Sinha DO Kataria 《Pramana》1999,53(3):529-533
Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies.
Coupled channel calculations incorporating couplings to 2+ and 3− states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements
had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer
were carried out for 46,48Ti+61Ni systems. The present paper gives the results of these studies. 相似文献