New strong interactions: From QCD to LHC

The concept of strong interactions need not be limited to the sector of physics taken by QCD. While this domain is investigated by RHIC, LHC will be able to probe potential new strong interactions simultaneously: Finding the precise mechanism for electroweak symmetry breaking is one of the prime problems of physics. Intricately linked to this point is the question after the true nature or even the existence of the Higgs boson. Here, we present stronly interacting theories providing an explanation for the hierarchy problem and leading to a light composite Higgs boson, favoured by experimental data. Our variation of the standard model is consistent with precision data. We achieve this accordance by using technifermions in a higher representation of their gauge group. Anomaly conditions require at least one extra lepton family for some of the theories whereby they contain a natural dark matter candidate. We can accurately determine the masses of said leptons from experimental data.     

Limited resolution in complex network community detection with Potts model approach

According to Fortunato and Barthélemy, modularity-based community detection algorithms have a resolution threshold such that small communities in a large network are invisible. Here we generalize their work and show that the q-state Potts community detection method introduced by Reichardt and Bornholdt also has a resolution threshold. The model contains a parameter by which this threshold can be tuned, but no a priori principle is known to select the proper value. Single global optimization criteria do not seem capable for detecting all communities if their size distribution is broad.     

Influence of boric acid on the determination of iron in reactor coolant water by graphite furnace atomic absorption spectrometry

Summary The matric effect of boric acid was investigated in the determination of iron in the primary circuit coolant water of nuclear power plants by furnace atomic absorption spectrometry. The effect of boric acid was of particular interest. The method was applied during refuelling and maintenance periods and the results were used to interpret the chemical changes in the water.

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Einfluß von Borsäure auf die Bestimmung von Eisen in Reaktorkühlwasser durch GF-AAS

     

Novel coordination of a hydroxamic acid : Crystal structures of bis(glycinohydroxamoto)nickel(II) and tris(glycinohydroxamoto)cobalt(III)

The structures of two glycinohydroxamoto (GHA) complexes of Ni(II) and Co(III) have been determined by single-crystal X-ray diffraction methods. The crystals of Ni(GHA)₂ are monoclinic with a = 5.360(1), b = 7.315(4), c = 10.194(4) Å, β = 96.57(3), Z = 2, and space group P2₁/c. The crystals of Co(GHA)₃•1/2 H₂O are monoclinic with a = 22.467(19), b = 8.041(4), c = 13.700(11) Å, β = 116.01(7), Z = 8, and space group C2/c. The values of the final residuals R for Ni(GHA)₂ and Co(GHA)₃•1/2 H₂O are 0.0275 and 0.032, respectvely. The molecular structures of Ni(GHA)₂ and Co(GHA)₃ consist of a square planar and an octahedral coordination, respectively, with the glycinohydroxamato (NH₂CH₂CONOH⁻) ligands coordinating to the metal ion via the N (amino) and the N (NOH⁻). These two complexes are the first well-established cases of coordination of the NHO⁻ group of a hydroxamic acid to a transition metal via the nitrogen atom.     

Color Bricks: Building Highly Organized and Strongly Absorbing Multicomponent Arrays of Terpyridyl Perylenes on Metal Oxide Surfaces

Terpyridine‐substituted perylenes containing cyclic anhydrides in the peri position were synthesized. The anhydride group served as an anchor for assembly of the terpyridyl‐crowned chromophores as monomolecular layers on metal oxide surfaces. Further coordination with Zn²⁺ ions allowed for layer‐by‐layer formation of supramolecular assemblies of perylene imides on the solid substrates. With properly selected anchor and linker molecules it was possible to build high quality structures of greater than ten successive layers by a simple and straightforward procedure. The prepared films were stable and had a broad spectral coverage and high absorbance. To demonstrate their potential use, the synthesized dyes were employed in solid‐state dye‐sensitized solar cells, and electron injection from the perylene antennas to titanium dioxide was observed.     

Complexity of solution structures in nonlinear pricing

This paper characterizes and enumerates the possible solution structures in nonlinear pricing problem when the number of buyer types is given. It is shown that the single-crossing property, which is a standard assumption in the literature, reduces the complexity of solving the problem dramatically. The number of possible solution structures is important when the pricing problem is solved under limited information.     

Direct Evidence of Significantly Different Chemical Behavior and Excited‐State Dynamics of 1,7‐ and 1,6‐Regioisomers of Pyrrolidinyl‐Substituted Perylene Diimide

Novel bay‐functionalized perylene diimides with additional substitution sites close to the perylene core have been prepared by the reaction between 1,7(6)‐dibromoperylene diimide 6 (dibromo‐PDI) and 2‐(benzyloxymethyl)pyrrolidine 5 . Distinct differences in the chemical behaviors of the 1,7‐ and 1,6‐regioisomers have been discerned. While the 1,6‐dibromo‐PDI produced the corresponding 1,6‐bis‐substituted derivative more efficiently, the 1,7‐dibromo‐PDI underwent predominant mono‐debromination, yielding a mono‐substituted PDI along with a small amount of the corresponding 1,7‐bis‐substituted compound. By varying the reaction conditions, a controlled stepwise bis‐substitution of the bromo substituents was also achieved, allowing the direct synthesis of asymmetrical 1,6‐ and 1,7‐PDIs. The compounds were isolated as individual regioisomers. Fullerene (C₆₀) was then covalently linked at the bay region of the newly prepared PDIs. In this way, two separate sets of perylene diimide–fullerene dyads, namely single‐bridged (SB‐1,7‐PDI‐C₆₀ and SB‐1,6‐PDI‐C₆₀) and double‐bridged (DB‐1,7‐PDI‐C₆₀ and DB‐1,6‐PDI‐C₆₀), were synthesized. The fullerene was intentionally attached at the bay region of the PDI to achieve close proximity of the two chromophores and to ensure an efficient photoinduced electron transfer. A detailed study of the photodynamics has revealed that photoinduced electron transfer from the perylene diimide chromophore to the fullerene occurs in all four dyads in polar benzonitrile, and also occurs in the single‐bridged dyads in nonpolar toluene. The process was found to be substantially faster and more efficient in the dyads containing the 1,7‐regioisomer, both for the singly‐ and double‐bridged molecules. In the case of the single‐bridged dyads, SB‐1,7‐PDI‐C₆₀ and SB‐1,6‐PDI‐C₆₀, different relaxation pathways of their charge‐separated states have been discovered. To the best of our knowledge, this is the first observation of photoinduced electron transfer in PDI‐C₆₀ dyads in a nonpolar medium.