New practical synthesis of prazosin

A new four step synthesis of prazosin, 2-[4-(2-furoyl)piperazin-l-yl]-4-amino-6,7-dimethoxyquinazoline, has been described. The method is also adaptable for the preparation of other substituted 4-aminoquinazolines. The yields are good in every step and the reactions are performed with ease. Prazosin hydrochloride of high purity is obtained directly in the last step.     

Some aspects of approach to equilibrium in classical and quantum systems

Investigations of general properties of time evolution of both classical and quantum systems show that the evolution (on a microscopic level) is reversible, and, if there is an approach to equilibrium, it exists only in the sense of weak convergence and necessarily in both directions of time. In this connection attempts to derive irreversibility and the approach to equilibrium in the sense of strong convergence and without any loss of information (using the so-called Lyapunov converters) are discussed. After demonstrating their drawbacks, an alternative approach is proposed based on the spectral properties of the generator of the group. The relevant spectral criteria for the approach of both classical and quantum ensembles to equilibrium are given, and the decisive role of loss of information in obtaining stronger variants of convergence is emphasized. The asymmetry between initial and any other state —consisting of different levels of information needed to prepare the states—is proposed as an adequate explanation of irreversibility. The importance of the method of complex scaling in this context is discussed, and its application in proving some spectral properties in the quantal Hamiltonian formulation is stressed.     

Predictable quantum efficient detector for low optical flux measurements

Optical Review - The predictable quantum efficient detector (PQED) is a primary standard of optical power, which utilizes two custom-made induced-junction photodiodes that are mounted in a wedged...     

Pendulum in a Fermi liquid

The Fermi-liquid theory formulated by Landau is a basic paradigm of the behavior of an interacting many-body system. We present a new application of this theory to calculate the "Landau force" on a macroscopic object. We show that immersing a pendulum in a Fermi liquid can increase its oscillation frequency, and evidence of this has been observed in mixtures of (3)He and (4)He.     

Optical coherence tomography as a method of quality inspection for printed electronics products

Application of time domain, ultra high resolution optical coherence tomography (UHR-OCT) in printed electronics products’ quality inspection is demonstrated. Presented study was done using experimental UHR-OCT device based on a Kerr-lens mode locked Ti:sapphire femtosecond laser, photonic crystal fibre and modified, free-space Michelson interferometer. Possibilities of the technique are demonstrated by analysis of an RF antenna—example of printed electronics products. Measurements were done with submicron axial resolution, offered by UHR-OCT system developed in our laboratory. Such high resolution is necessary due to the thickness of material layers used in printed electronics. In addition to tomography imaging, numerical results were compared with data provided by two commercially available measurement devices: Wyko NT3300 optical profiler and Dektak 8 stylus profiler (both Veeco). Comparison of profile heights and their spatial correlation is presented. Ability for full volumetric reconstruction and accuracy justified with reference measurements prove OCT to be a reliable tool in printed electronics product testing.     

E-2-Benzylidenebenzocycloalkanones. IV. Studies on transmission of substituent effects on C NMR chemical shifts of E-2-(X-benzylidene)-1-tetralones, and -benzosuberones. Comparison with the C NMR data of chalcones and E-2-(X-benzylidene)-1-indanones

Single substituent parameter (SSP) and dual substituent parameter (DSP) analyses were applied to study the transmission of substituent effects on selected ¹³C NMR chemical shifts of the cyclic chalcone analogues, E-2-(4′-X-benzylidene)-1-tetralones (2) and E-2-(4′-X-benzylidene)-1-benzosuberones (3). In order to study how the geometry of the cyclic chalcone analogues affects the transmission of substituent effects similar investigations with the respective chalcones (4) were also performed. The results obtained earlier with the five-membered analogue E-2-(4′-X-benzylidene)-1-indanones (1) were also involved in the comparisons. Geometry optimization of the unsubstituted 1a, 2a, 3a and 4a as well as the substituted 2 and 3 was performed by ab initio quantum chemical calculations. Both SSP and DSP analyses reflected that resonance effects contribute more to the chemical shift of C- (C2), while inductive effects primarily affect that of C-β (C10) of the enone moiety of all the four series. This latter effect, however, is far not as pronounced as that of the former one. It was found that DSP analysis data (ρ_F and ρ_R values) of transmission of substituent effects on the δC2 data can serve as a measure of choice to study the conformation (planarity) of the investigated enones in the four series.     

Sub-spectral analysis of the 100 MHz P.M.R. spectrum of 15N-pyrrole

A small range of compounds contain ions from two transition groups, 3d and 4f. Most of these enter an ordered antiferromagnetic state only at liquid helium temperatures, and the internal fields are 1 tesla or less. Experiments are suggested on various single crystals. Measurements by electron spin resonance on impurity ions in antiferromagnetic dysprosium phosphate show that similar compounds could be used for experiments on nuclear orientation with nuclear magnetic resonance.