Properties of C60 polymerized under high pressure and temperature

60 polymers. Pure and mixed phase polymeric samples were synthesized by simultaneously subjecting microcrystalline C₆₀ powder or pellets to various pressures () and temperatures (). The optical spectra of the orthorhombic, tetragonal, and rhombohedral C₆₀ polymer phases are observed to be quite distinct and rich. These spectra exhibit numerous lines and an overall downshift in frequency relative to C₆₀ is observed, consistent with a loss of double bonds from the fullerene cage. The LDMS spectra of a sample synthesized at under hydrostatic conditions and , exhibited a succession of clear peaks at mass numbers corresponding to , similar to the LDMS data on the C₆₀ photopolymer. This is taken as further evidence for interfullerene bonds in these high-pressure polymers. The XRD pattern of this sample indicates the presence of a strong texture in the sample. Received: 14 November 1996/Accepted: 8 January 1997     

Anionic polymerization of styrene in ionic liquids

For the first time anionic polymerization of styrene has been successfully carried out at ambient temperatures in an ionic liquid, providing milder reaction conditions than classical methods. The addition of the zwitterion provides better dissociation of the metal cation based initiators and the IL based reaction allows the use of a much milder Lewis base initiator than is usually required. The present method also eliminates the traditional solvents and rigorous reaction conditions.     

Reflections and observations on various approaches to strategic planning

Recent articles in the Operational Research Quarterly in the United Kingdom have discussed the suitability of optimality as the sole, or even the most appropriate, criterion relevant to decision making. This is perhaps particularly so in the case of strategic planning, in which decisions more likely have to be made in situations of uncertainty. Alternative criteria such as satisficing, robustness and stability have been proposed and the paper reflects on their relevance. This paper draws attention to the fact that strategic planning problems often involve multiple, often noncommensurable, objectives and stresses the importance of engaging decision-makers in an interactive dialogue in such situations. In the concluding observations, examples of two different approaches are given, both within the context of mathematical programming.     

Comparison of high-performance liquid chromatography with electrochemical detection and gas chromatography-mass fragmentography for the assay of salsolinol, dopamine and dopamine metabolites in food and beverage samples

High-performance liquid chromatography with electrochemical detection (HPLC-ED) and combined gas chromatography--mass spectrometry in the single-ion monitoring mode (GC--MS-SIM) have been used for the determination of salsolinol, dopamine, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxyphenylethanol and norepinephrine in a selection of food and beverage samples. The unique specificity of the SIM mode allows a simple one-step extraction to be used even for complex sample matrices. We have been able to demonstrate the quantitative and qualitative advantages offered by GC--MS over HPLC--ED by direct comparison of the chromatographic data obtained. We demonstrate that the specificity of SIM and the benefits offered by the incorporation of deuterated internal standards make GC--MS-SIM the method of choice for valid identification and precise quantitation of salsolinol, dopamine and dopamine metabolites in a complex sample matrix.     

The 2,1-benzisothiazolo[2,3-b]-2,1-benzisothiazole system,synthesis and properties

2,2′-Diaminodiphenylmethane and its 4,4′-dibromo-derivative both react with N-sulfinylmethanesulfon-amide to form 2,1-benzisothiazole derivatives. Methylation or acetylation of these provides examples of the hypervalent sulfur 2,1-benzisothiazolo[2,3-b]-2,1-benzisothiazole system. The nmr spectra of these compounds are discussed.     

The supersymmetric QCD and KL-KS mass difference

Assuming that globally supersymmetric QCD accounts for the discrepancy between the experimental value of the K_L-K_S mass difference and that obtained from the electroweak model, we extract constraints on the squark masses for different evaluations of the K^O$\text{K}$^O hadronic matrix element.     

Evaluating Re-order Levels and Probabilities of Stockout during a Lead Time for Some Stock-Control Models

When several suppliers are concurrently used to replenish one stock item, it is often of interest to compute the mean and the variance of the effective lead time, i.e., the minimum of all lead times. However, in many cases, especially with non-identical lead time distributions, these quantities do not have closed form expressions and their calculation can be complicated. Difficulty in computation also arises in evaluating demand during lead time, even if there is only one supplier. This paper presents a numerical integration method using Gaussian quadrature to evaluate the effective lead time mean and variance, re-order level and the probability of stockout during the effective lead time. The Gaussian quadrature rules are easy to implement and several data sets are used in the paper to demonstrate the method.     

Magnetic properties of rare-earth β-enaminoketone metallomesogens

Reaction of β-enaminoketones with lanthanide salts leads to mesomorphic complexes displaying an S_A mesophase. The mesophase was characterized using X-ray scattering, EPR and magnetic susceptibility. A very high magnetic anisotropy was deduced for a complex containing dysprosium.     

Molecular discrimination and contrast enhancement using a scanning coherent anti-stokes Raman microscope

New applications of a nonlinear optical microscope using coherent anti-Stokes Raman scattering (CARS) are presented. Excellent molecular discrimination using chemically similar molecular species and signal contrast enhancement using digital image processing are demonstrated. Limitations of the technique and future applications are discussed.