New Method for the Synthesis of 2-Acylamino-1-benzothiophene-3-carboxamide Derivatives from the Corresponding Esters

An unusual chemical method has been applied for the preparation of 1-benzothiophene-3-carboxamide derivatives from esters by reaction with lithium amide in tetrahydrofurane.     

Distinct Distances in Homogeneous Sets in Euclidean Space

It is shown that every homogeneous set of n points in d-dimensional Euclidean space determines at least distinct distances for a constant c(d) > 0. In three-space the above general bound is slightly improved and it is shown that every homogeneous set of n points determines at least distinct distances.     

Neighbor games and the leximax solution

Neighbor games arise from certain matching or sequencing situations in which only some specific pairs of players can obtain a positive gain. As a consequence, the class of neighbor games is the intersection of the class of assignment games (Shapley and Shubik (1972)) and the class of component additive games (Curiel et al. (1994)). We first present some elementary features of neighbor games. After that we provide a polynomially bounded algorithm of order p ³ for calculating the leximax solution (cf. Arin and Iñarra (1997)) of neighbor games, where p is the number of players. This authors work has been supported by CentER and the Department of Econometrics, Tilburg University and by the Foundation for the Hungarian Higher Education and Research (AMFK).     

Near optimal bounds for the Erdős distinct distances problem in high dimensions

We show that the number of distinct distances in a set of n points in ℝ ^d is Ω(n ^{2/d − 2 / d(d + 2)}), d ≥ 3. Erdős’ conjecture is Ω(n ^2/d ).     

Distinct Distances in the Plane

It is shown that every set of n points in the plane has an element from which there are at least cn ^6/7 other elements at distinct distances, where c>0 is a constant. This improves earlier results of Erdős, Moser, Beck, Chung, Szemerédi, Trotter, and Székely. Received November 15, 2000, and in revised form December 13, 2000. Online publication April 6, 2001.     

Establishing a new acoustical laboratory, planning, experiments, experiences

A significant part of the input data for planning the acoustical quality of building is the result of laboratory measurements. Detailed modelling of complex phenomena of sound transmission, like structure borne sound propagation can be solved based on on well planned laboratory experiences. However it seems the constructional details of the testing facilities have important effect on the measured results. The paper describes the process of planning the testing facilities of the Laboratory of Building Acoustics, TU Budapest, which operate as a standardised laboratory, a modelling “tool” for flanking transmission in research and development and which is utilised in teaching too. Some results and conclusions of recent experiments are also reported and discussed here related to the sound reduction index of a heavy brick wall without and with flanking transmission, to the impact sound insulation between the rest of a stair and an adjacent room and also to a possibility to determine the reduction of impact sound transmission of floor coverings.     

Interaction of HNCO with Au(111) surfaces

The surface chemistry of isocyanic acid, HNCO, and its dissociation product, NCO, was studied on clean, O-dosed and Ar ion bombarded Au(111) surfaces. The techniques used are high resolution energy loss spectroscopy (HREELS) and temperature-programmed desorption (TPD). The structure of Ar ion etched surface is explored by scanning tunneling microscopy (STM). HNCO adsorbs molecularly on Au(111) surface at 100 K yielding strong losses at 1390, 2270 and 3230 cm^? 1. The weakly adsorbed HNCO desorbs in two peaks characterized by T_p = 130 and 145 K. The dissociation of the chemisorbed HNCO occurs at 150 K to give NCO species characterized by a vibration at 2185 cm^? 1. The dissociation process is facilitated by the presence of preadsorbed O and by defect sites on Au(111) produced by Ar ion bombardment. In the latter case the loss feature of NCO appeared at 2130 cm^? 1. Isocyanate on Au(111) surface was found to be more stable than on the single crystal surfaces of Pt-group metals. Results are compared with those obtained on supported Au catalysts.     

T3P®‐Mediated One‐Pot Synthesis of Bis(α‐aminophosphonates)

Two series of bis(α‐aminophosphonates) were synthesized by one‐pot three‐component reactions using 4‐phenylenediamine, an aldehyde (2 equiv) and a phosphite (2 equiv), or terephtalaldehyde, an amine (2 equiv), and a phosphite (2 equiv) together with propylphosphonic anhydride (T3P®) in both series as a coupling reagent. The bis(α‐aminophosphonates) were obtained in moderate to excellent yields. The condensations take place under mild conditions and the isolation of the products is simple.     

An algorithm for finding the nucleolus of assignment games

Assignment games with side payments are models of certain two-sided markets. It is known that prices which competitively balance supply and demand correspond to elements in the core. The nucleolus, lying in the lexicographic center of the nonempty core, has the additional property that it satisfies each coalition as much as possible. The corresponding prices favor neither the sellers nor the buyers, hence provide some stability for the market. An algorithm is presented that determines the nucleolus of an assignment game. It generates a finite number of payoff vectors, monotone increasing on one side, and decreasing on the other. The decomposition of the payoff space and the lattice-type structure of the feasible set are utilized in associating a directed graph. Finding the next payoff is translated into determining the lengths of longest paths to the nodes, if the graph is acyclic, or otherwise, detecting the cycle(s). In an (m,n)-person assignment game withm = min(m,n) the nucleolus is found in at most 1/2·m(m + 3) steps, each one requiring at mostO(m·n) elementary operations.