A minting policy for commemorative coins

The official commemorative coins have exhibited an extraordinary increase in price during the last ten years. This has been accompanied by a commensurate increase in the sale of new issues. In 1973 alone, the Israeli Treasury generated a net profit of over 5 million dollars from the sale of commemorative coins. The Bank of Israel was interested in safeguarding the future profit generating potential of minting new coins and in learning how decisions relating to minting policy influence the long-range profits. Therefore, (1) the relationship between various coin characteristics and economic data, and the market price of old issues, as well as (2) the relationship between the profit from a new issue and the gains experienced from older issues and other coin characteristics, were determined using regression analysis. Based on the above, a dynamic model was constructed to show the relationship between the controllable variables (various minting policies) and the long-range present value of the net profit to be generated by them. Since the derivation of an optimal analytic solution seemed infeasible, several minting policies were simulated, and as a result a set of improved policies recommended.     

Rigid backbone polymers. I. Polyisocyanides

Concentrated solutions of poly(n-octyl isocyanide) exhibit a mesomorphic structure, most probably nematic in nature. Poly(n-butyl isocyanide) and poly(benzyl isocyanide), of the molecular weights at our disposal, failed to show similar behavior. Upon acidification poly(n-butyl isocyanide) does not change, but the other two polymers turn essentially black. Infrared and proton NMR clearly demonstrate that upon acidification, poly(n-butyl isocyanide) and poly(benzyl isocyanide) are protonated on the nitrogen atom. This process is reversible. Carbon-13 NMR and x-ray patterns indicate that no chemical rearrangement or conformational changes take place upon acidification. This conclusion is supported by infrared studies and by inference from the poor electrical conductivity of the solid acidified polymers.     

On the nature of intramolecular dephasing processes in polyatomic molecules

Intramolecular dephasing processes in polyatomic molecules are discussed with relation to coherent transient spectroscopy, radiationless transitions, multiphoton molecular processes, and overtone spectroscopy. A distinction is made between proper and improper dephasing processes (PDP, IDP) depending on whether they arise due to changes in populations or not. It is shown that the type of experiment and, consequently, the way we partition the hamiltonian are closely related to this distinction. We consider several experimental and theoretical approaches for studying intramolecular dynamics and discuss under what conditions it is necessary and useful to introduce explicitly dephasing interactions.     

Universal incommensurate structures

Certain phase transitions in quasiperiodic systems are characterized byuniversal structures. In these cases the functional form of the order parameter corresponding to the modulated phase,P(r), is determined by the symmetry properties of the system and is independent of the details of the associated Landau-Ginzburg model. Here we consider a simple one-dimensionalXY-like model corresponding to this type of phase transition. The universal modulated structure of this model is calculated numerically at various points along the critical line.     

Sequential sampling schemes and other statistical techniques in quality of service business surveys

While there is a general consensus in the business community regarding the importance of quality service surveys in improving the company's business results, relatively little attention was devoted to the theoretical aspects of data analysis and modelling which can increase substantially the effectiveness of those surveys. Using the data from a real‐life project, we present here the developments and improvements achieved in the three stages that ultimately yield the conclusions from the survey: the analysis of the historical data, the design of the sampling method for the current survey and the development of specific indices for differentiating among the units of the financial institution. The statistical techniques fitted to historical data helped both in assessing the relative contributions of the various aspects of service, the overall perceived quality of service, as well as in providing the theoretical grounds for reducing the size of the questionnaire and thus increasing the reliability of the received replies. The sequential sampling scheme designed for this survey was particularly suitable to address the managements concerns. Finally, the classes of quality service based on the quality indices developed in the project contributed substantially to the ability of the management to rank and reward differentially the branches of the financial institution. Copyright © 2002 John Wiley & Sons, Ltd.     

Core-clad silver halide fibers with few modes and a broad transmission in the mid-infrared

There is interest in single-mode fibers that are highly transparent in the mid-infrared. Such fibers would be valuable for spectroscopy, interferometry, and heterodyne detection. We have developed core-clad fibers made of crystalline silver halides with an external diameter of 900 microm and core diameters as small as 60 microm. These fibers exhibit homogeneous core and cladding regions, round cores, and smooth core-cladding interfaces. The 60 microm fibers support roughly 70 modes and have low losses over a broad spectral range in the mid-infrared. This will pave the road for the development of single-mode mid-infrared fibers. ie ty of America     

Dephasing-induced vibronic resonances in difference frequency generation spectroscopy

The difference frequency generation (DFG) signal from a two electronic level system with vibrational modes coupled to a Brownian oscillator bath is computed. Interference effects between two Liouville space pathways result in pure-dephasing-induced, excited-state resonances provided the two excitation pulses overlap and time ordering is not enforced. Numerical simulations of two-dimensional DFG signals illustrate how the ground and excited electronic state resonances may be distinguished.     

Coherent x-ray Raman spectroscopy: a nonlinear local probe for electronic excitations

Nonlinear x-ray four-wave mixing experiments are becoming feasible due to rapid advances in high harmonic generation and synchrotron radiation coherent x-ray sources. By tuning the difference of two x-ray frequencies across the valence excitations, it is possible to probe the entire manifold of molecular electronic excitations. We show that the wave vector and frequency profiles of this x-ray analogue of coherent Raman spectroscopy provide an excellent real-space probe that carries most valuable structural and dynamical information, not available from spontaneous Raman techniques.