New derivatives of coumarin: 2-(N-R-imino)-2H-1-benzopyrans

Methods of synthesizing previously unknown derivatives of coumarin — 2-(N-R-imino)-2H-1-benzopyrans, where R = Alk, Ar — are proposed. Possibilities of alternative synthetic schemes are discussed, and hypotheses concerning probable mechanisms of the reactions are formulated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 760–766, June, 1994. Original article submitted May 23, 1994.     

The Assessment of Reservation Prices of an Intermediate R&D Result and Patent Reward Under Oligopolistic Competitive Behaviour

One of the shortcomings of R&D evaluation is a lack of emphasis on analytical assessment of the value of an on-going R&D project. This paper addresses the problem concerning the distributive aspect of access to superior knowledge. Decision tree analysis and probability models appear to be appropriate tools for assessing the values of an intermediate result and patent reward of a firm's R&D decision in an environment of perfect information and oligopolistic competition. The assessed values are used as minimum prices acceptable to the firm when the knowledge is disseminated to the public. This paper will attempt to resolve this problem through the determination of the appropriate values of the reservation price of the first-stage invention in terms of the final reward and of a patent reward for which the inventor is willing to apply.     

Direct SCF structure optimization of large molecules on networks of workstations

A program to optimize the structure of large molecules at the Hartree–Fock level of theory running concurrently on a network of workstations is presented. Problems encountered in obtaining nearly optimal speedup and their solutions are discussed. A simple scheduling algorithm is presented that enables up to 99.5% of the code to run in parallel. © 1993 John Wiley & Sons, Inc.     

Spin-trapped hydroxyl free radicals studied at low field by Field-Cycled Dynamic Nuclear Polarization

The technique of Field-Cycled Dynamic Nuclear Polarization (FC-DNP) involves the EPR irradiation of a free radical solution and the subsequent observation of the NMR signal, the experiment being carried out at a range of magnetic field strengths in order to measure the free radical’s EPR spectrum. In this work FC-DNP has been used to study the EPR spectrum of DMPO spin-trapped hydroxyl free radicals at magnetic field strengths between 0.5 mT and 13.0 mT (5–130 Gauss). The low-field EPR spectrum contains six separate EPR lines, in contrast to the well-known X-band spectrum where only four are seen. Knowledge of the spin-adduct’s EPR spectrum will be of use to workers involved in low-field EPR, especially those conducting biological or in-vivo spin-trapping experiments.     

Systematics of flux jumps and the stabilizing effect of flux creep in a La1.86Sr0.14CuO4 single crystal

Flux jumps have been observed in a large (138 mg) single crystal of La_1.86Sr_0.14CuO₄. Both complete and incomplete flux jumps are observed with the energy dissipated by complete flux jumps consistent with temperature rises to nearly T_c. The systematics of these flux jumps with respect to field history, temperature and the time duration of the hysteresis measurements are reported. The field at which flux jumps first occur and their subsequent spacing are not consistent with a simple adiabatic theory of flux jumps for our experimental conditions. Instead, the crystal is observed to be stabilized against flux jumps by flux creep which occurs during the time interval over which field steps are accomplished as well as during imposed time intervals between field steps.     

Optical switching between bistable soliton states: a theoretical review

In this paper we summarize what is currently known about optical switching between bright bistable soliton states in one and higher dimensions. A guideline to selecting media with appropriate intensity-dependent refractive indices to support bistable solitary waves is presented. The stability criterion for robustness of the solitary waves is discussed. Finally, some methods and numerical examples of optical switching are presented.     

A Faster Deterministic Maximum Flow Algorithm

Cheriyan and Hagerup developed a randomized algorithm to compute the maximum flow in a graph with n nodes and m edges in O(mn + n² log²n) expected time. The randomization is used to efficiently play a certain combinatorial game that arises during the computation. We give a version of their algorithm where a general version of their game arises. Then we give a strategy for the game that yields a deterministic algorithm for computing the maximum flow in a directed graph with n nodes and m edges that runs in time O(mn(log_{m/n log n}n)). Our algorithm gives an O(mn) deterministic algorithm for all m/n = Ω(n^ε) for any positive constant ε, and is currently the fastest deterministic algorithm for computing maximum flow as long as m/n = ω(log n).     

Properties of neodymium-doped aluminophosphate laser glasses

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 1, pp. 90–95, January, 1992.     

Application of Novel Focusing Mirrors in Gyrotron Transmission Lines

A novel focusing mirror based on the shifting of the beam phase according to the Gaussian beam optics enabled us to realize a focusing elements with different focal lengths in different directions and to convert the gyrotron output into a Gaussian-like beam. In this paper, we compare the quality of beams produced by the new system (which includes novel mirrors) and a conventional system consisting of a quasi-optical antenna, an ellipsoidal mirror and two parabolic cylinder mirrors.     

Hessian Measures III

In this paper, we continue previous investigations into the theory of Hessian measures. We extend our weak continuity result to the case of mixed k-Hessian measures associated with k-tuples of k-convex functions, on domains in Euclidean n-space, k=1,2,…,n. Applications are given to capacity, quasicontinuity, and the Dirichlet problem, with inhomogeneous terms, continuous with respect to capacity or combinations of Dirac measures.