A Primitive Non-symmetric 3-Class Association Scheme on 36 Elements with p11 = 0 Exists and is Unique

In this paper we construct a primitive, non-symmetric 3-class association scheme with parameters v = 36, v₁ = 7, p¹₁₁ = 0 and p²₁₁ = 4 and show that such a scheme is determined by its parameters.     

Dynamic Point Location in General Subdivisions

The dynamic planar point location problem is the task of maintaining a dynamic set S of n nonintersecting (except possibly at endpoints) line segments in the plane under the following operations:

• Locate (: point): Report the segment immediately above , i.e., the first segment intersected by an upward vertical ray starting at ;

• Insert (: segment): Add segment to the collection of segments;

• Delete (: segment): Remove segment from the collection of segments.

We present a solution which requires space O(n) and has query and insertion time O(log n log log n) and deletion time O(log²n). The bounds for insertions and deletions are amortized. A query time below O(log²n) was previously only known for monotone subdivisions and subdivisions consisting of horizontal segments and required nonlinear space.     

Silver nitrate-acetonitrile and iodine-benzene complexes as studied by NMR in thermotropic liquid crystals

Silver nitrate-acetonitrile and π iodine-benzene complexes in thermotropic liquid crystals have been studied by ¹H, ²H, and ¹³C NMR spectroscopy and by optical microscopy. Evidence for at least two silver complexes in each liquid crystal is presented.     

On the existence of <Emphasis Type="Bold">1, 3</Emphasis>P <Emphasis Type="Bold">o</Emphasis> resonances in H<Superscript>-</Superscript> between n = 2 and 3 H thresholds

We examine the influence of relativistic and QED effects on the existence of the ^1,3P ^o H^- resonances between n = 2 and 3 hydrogen thresholds, the relativistic and QED corrections and the coupling effects between the high singlet and triplet states are considered as first-order perturbations. We firstly obtain accurate non-relativistic resonant energies and widths of fifteen ¹P ^o resonances, and fifteen ³P ^o resonances. The fifteen ¹P ^o resonances are classified to be ₃ (2, 0) ^- _n ( 4 ? n ? 12) and ₃ (1, 1) ⁺ _n ( 3 ? n ? 8). The fifteen ³P ^o resonances are classified to be ₃ (2, 0) ⁺ _n ( 3 ? n ? 12) and ₃ (1, 1) ^- _n ( 4 ? n ? 8). We found there exist six Feshbach resonances for ₃ (2, 0) ^- _n (¹P ^o ) series, four Feshbach resonances for ₃ (1, 1) ⁺ _n (¹P ^o ) series, seven Feshbach resonances for ₃ (2, 0) ⁺ _n (³P ^o ) series, and three Feshbach resonances for ₃ (1, 1) ^- _n (¹P ^o ) series. Received 22 February 2002 Published online 24 September 2002     

Analysis of semiconducting materials by high-resolution radiofrequency glow discharge mass spectrometry

The analytical capabilities of a high-resolution mass spectrometer in combination with a 13.56 MHz glow discharge ion source for the analysis of semiconducting materials (silicon carbide and gallium arsenide) were studied. It was shown that single positively charged ions of sample material have about 10 eV higher average energy than the ions of the discharge and residual gas. Therefore effective energy separation of the ions of analyte from the ions of the discharge and residual gas was achieved by adjusting the ion transfer optics (breadth and position of energy slit), which improves the analytical capabilities of the developed method.Some analytical applications are presented to illustrate the performance of r.f. GDMS for the bulk analysis of semiconducting materials. The results of the trace element analysis of gallium arsenide and silicon carbide samples are compared with data of independent methods (LIMS, ICP-AES, SIMS).Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthdayOn leave from the Institute of Inorganic Chemistry, 630090 Novosibirsk, Russia     

The universal nilpotent group compactification of a semigroup

The purpose of this paper is to introduce an algebra of functions on a semitopological semigroup and to study these functions from the point of view of universal semigroup compactification. We show that the corresponding semigroup compactification of this algebra is universal with respect to the property of being a nilpotent group.

     

Olefin terpolymerizations. II. 4-vinylcyclohexene and cyclooctadiene

4-Vinylcyclohexene (VCH) and cyclooctadiene (COD) were investigated as termonomers in EPDM (ethylene/propylene/diene) synthesis by using rac-ethylenebis (1-η⁵-indenyl) zir-conium dichloride ( 1 ) as a catalyst precursor. Homopolymerizations of VCH, vinylcycloh-exane and cyclohexene were compared. The parameter K_πκ_p, which is the apparent rate constant for Ziegler-Natta polymerization, is about the same for VCH and vinylcyclohexanebut is 10 times smaller for cyclohexene. Therefore, the linear olefinic double bond is more active than the cyclic internal double bond. VCH reduces ethylene polymerization rate but not propylene polymerization rate in copolymerizations. In terpolymerizations, VCH tends to suppress ethylene incorporation especially at elevated polymerization temperature and Lowers the polymer MW by about two-fold. COD has very low activity as a termonomer. © 1995 John Wiley & Sons, Inc.     

New fluorescence probes for monitoring the kinetics of laser-initiated polymerization

Several new fluorescence probes useful for following photopolymerization have been characterized. Among these are probes which can be used in rapidly gelling monomer mixtures and for photochemical polymerization initiated by very high laser powers. Systems which can be used with polyolacrylates and either with visible initiators or with UV initiators are reported. © 1993 John Wiley & Sons, Inc.     

On finite element approximation and stabilization methods for compressible viscous flows

This work is devoted to the numerical solution of the Navier–Stokes equations for compressible viscous fluids. Finite element approximations and stabilization techniques are addressed. We present methods to implement discontinuous approximations for the pressure and the density. An upwinding methodology is being investigated which combines the ideas behind the stream line Petrov–Galerkin method and the flux limiter methods aiming to introduce numerical diffusion only where it is necessary.