Vapoluminescent Behavior and the Single-Crystal-to-Single-Crystal Transformations of Chloroform Solvates of [Au2(μ-1,2-bis(diphenylarsino)ethane)2](AsF6)2

The mono- and di-chloroform solvates of [Au₂(μ-1,2-bis(diphenylarsino)ethane)₂](AsF₆)₂ undergo single-crystal-to-single-crystal transformations that result in gain (over 12 hours) or slow loss (over five years) of only one chloroform molecule. The change in solvation results in changes in the structure and luminescence of the digold cation. The cation consists of a pair of slightly bent As-Au-As units that are connected through the two bridging dpae ligands and by aurophilic interactions with Au⋅⋅⋅Au contacts of 3.05152(15) Å in the disolvate or 2.9570(5) Å in the monosolvate.     

Some remarks on Nelson's stochastic field

An attempt to extend Nelson's stochastic quantization procedure to tensor fields indicates that the results of Guerra et al. on the connection between a euclidean Markov scalar field and a stochastic scalar field fails to hold for tensor fields.     

Features in Distribution of Wavefunctions of Few-Body Systems

The bbody, 4-body and 5-body quantum mechanical systems with pairwise interactions having repulsive core and attractive tail and with completely symmetric permutation symmetry in the spatial wavefunctions are studied. The spatial distribution of the wavefunctions of the low-lying O⁺ states is investigated in detail. The features of the geometric structures and of the internal motions of each of these states are revealed. Certain modes of the internal motions are discovered.     

High-Temperature Phase Transition in N(CH3)4CdCl3 Studied Using Static NMR and MAS NMR

To clarify the nature of microscopic structural changes of N(CH₃)₄CdCl₃ at high temperatures, the nuclear magnetic resonance (NMR) spectra of the protons and carbons in N(CH₃)₄CdCl₃ were measured. NMR studies of the ¹H and ¹³C spin–lattice relaxation time, T _1ρ, in the rotating frame were also performed. No changes in the T _1ρ of ¹H and ¹³C associated with the N(CH₃)₄ groups were observed at the high-temperature transition from phase I to phase I′. However, the ¹⁴N NMR spectra reflected changes in the structural geometry during the transition to phase I′, indicating that this transition is driven by N(CH₃)₄.     

Applications of geometric means on symmetric cones

Let V be a Euclidean Jordan algebra, and let be the corresponding symmetric cone. The geometric mean of two elements a and b in is defined as a unique solution, which belongs to of the quadratic equation where P is the quadratic representation of V. In this paper, we show that for any a in the sequence of iterate of the function defined by converges to a. As applications, we obtain that the geometric mean of can be represented as a limit of successive iteration of arithmetic means and harmonic means, and we derive the L?wner-Heinz inequality on the symmetric cone Furthermore, we obtain a formula which leads a Golden-Thompson type inequality for the spectral norm on V. Received October 5, 1999 / Revised March 6, 2000 / Published online October 30, 2000     

Plant location and procurement planning in knockdown production systems

We consider an integrated problem of plant location and capacity planning for components procurement in knockdown production systems. The problem is that of determining the schedule of opening components manufacturing plants, plans for acquisition of capacities in opened components manufacturing plants, and plans for components procurement in final assembly plants with the objective of minimizing the sum of fixed costs for opening plants, acquisition and operation costs of facilities, and delivery and subcontracting costs of components. The problem is formulated as a mixed integer linear program and solved by a two-stage solution procedure. In the solution procedure, the problem is decomposed into two tractable subproblems and these subproblems are solved sequentially. In the first stage, a dynamic plant location problem is solved using a cut and branch algorithm based on Gomory cuts, while a multiperiod capacity planning problem is solved in the second stage by a heuristic algorithm that uses a cut and branch algorithm and a variable reduction scheme. The solution procedure is tested on problems of a practical size and results show that the procedure gives reasonably good solutions.     

Microwave-assisted synthesis and photoluminescence of MMoO4 (M=Ca,Ba) particles via a metathetic reaction

MMoO₄ (M=Ca, Ba) particles were synthesized by a metathetic reaction in ethylene glycol assisted by cyclic microwave irradiation followed by further heat-treatment. The MMoO₄ (M=Ca, Ba) particles were well crystallized after heat-treatment at 400–600 °C for 3 h. The microstructures exhibited fine morphologies with sizes of 0.5–1 μm and 1.5–2 μm for the CaMoO₄ and BaMoO₄ particles, respectively. The synthesized MMoO₄ (M=Ca, Ba) particles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The optical properties were examined by photoluminescence emission and Raman spectroscopy.     

In-Solution Derivatization and Headspace Gas Chromatography–Mass Spectrometry for 56 Carbonyl Compounds in Tobacco Heating Products,Traditional Tobacco Products and Flavoring Capsules

Chromatographia - Optimal derivatization conditions were established for the simultaneous determination of 12 aliphatic saturated aldehydes, 8 aliphatic saturated ketones, 4 cyclic ketones, 3...     

Molecular Recognition in Self‐Assembled Integrated Circuits: Getting Smaller while under Control

Available in small print : Block copolymer lithography has great potential for reducing the size and fabrication time of integrated circuits. Hydrogen‐bonding‐mediated molecular recognition in self‐assembly processes can be used to produce highly ordered square arrays of block copolymers on the surface of a silicon substrate (see picture).

     

The effects of cis–trans configuration of cyclohexane multi-carboxylic acids on colloidal forces in dispersions: steric, hydrophobic and bridging

The effects of cis- and trans-1,2-, trans-1,4-cyclohexanedicarboxylic acid, 95% cis-1,3,5-cyclohexane tricarboxylic acid and cis-1,2,3,4,5,6-cyclohexanehexacarboxylic acid on the yield stress–pH behaviour of concentrated ZrO₂ dispersions are reported. Adsorbed cis-1,2,3,4,5,6-cyclohexanehexacarboxylic acid imparts predominantly steric interactions. It forms a steric barrier keeping the interacting particles apart. Adsorbed cis- and trans-1,2 increase the maximum yield stress and this was attributed to a hydrophobic force resulting from the part of the cyclohexane ring sticking out into the solution which is devoid of charged or hydrophilic group. Adsorbed trans-1,4 increases the maximum yield stress by at least threefold and its configuration favours strong bridging interaction with an adjacent particle. Predominantly, cis-1,3,5 also increases the maximum yield stress but only by 60% at the same additive concentration. This was attributed to a smaller degree of bridging.