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  • 1
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; bark beetle ; western pine beetle ; pheromone ; interruption ; behavior ; release device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The number of western pine beetles,Dendroctonus brevicomis, trapped at the center of three 90 × 90-m plots was reduced during a 16-hr period after surrounding an attractive source ofexo-brevicomin, frontalin, and myrcene with 16, 48, or 168 sources of the same attractant. Compounds were released from the center of the plot at 1 mg/16 hr/compound, and from the surrounding sources at 4–280 mg/16 hr/compound. About half of these amounts was released between 1530 hr and 1930 hr, the period of peak beetle flight. No treatment differences were apparent in reduction of catch within the range of release rates and spacings tested. When compounds were released continuously from 168 stations for 17 days, catch at the center of a plot was generally lower than catch before or after this period, but fluctuated daily. More beetles were caught on traps hung on ponderosa pines within a plot and the number of these traps catching beetles was greater when compounds were released from all stations than from only the center station. Beetles caught on traps were attracted into the plots from the surrounding forest, but appeared to be dispersed within the plot when compounds were released from many stations.D. brevicomis attacked at least 91 trees in the plots, of which 25 were killed during two summers.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleptera ; Scolytidae ; bark beetle ; western pine beetle ; attractant rate ; pheromone ; exo-brevicomin ; frontalin ; myrcene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Racemicezo-brevicomin, racemic frontalin, and myrcene were released at two proportions (5∶1∶400 and 1∶1∶1), each at three levels (1 ×, 10 ×, and 100 ×) in a ponderosa pine forest in central California. The 5∶1∶400 mix was based on an estimate of the relative amounts released from a ponderosa pine under attack by the western pine beetle,Dendroctonus brevicomis. MoreD. brevicomis were trapped at a source of the three compounds released at 5∶1∶400 than were trapped at a source released at 1∶1∶1, at all three levels, but this difference was statistically significant only at the 1 × and 10 × levels. Sex ratio of trapped beetles and distribution of catch at the source of attractant and 5 m away apparently did not differ between relative release rates.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 113-122 
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; bark beetle ; western pine beetle ; pheromone ; attractant ; inhibitor ; exo-brevicomin ; frontalin ; myrcene ; verbenone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract exo-Brevicomin (E), frontalin (F), and myrcene (M) were released at two rates 10-fold apart with verbenone at four rates 10-fold apart, and without verbenone in plots with one trap on a vertical cylinder at the pheromone source and one trap on each of four cylinders 5 m away. Catch of the western pine beetleDendroctonus brevicomis decreased with increasing levels of verbenone at both release rates of EFM, but not all differences in catch were statistically significant. Significantly more beetles were caught at the high rate of EFM than at the low rate, combining all rates of verbenone. The percent of total beetles caught at the center trap tended to decrease with increasing rates of verbenone, but the only statistically significant differences were at the low rate of EFM.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 965-977 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Liquid crystal polymers (LCP) have been developed for the first time as a thermoplastic matrix for high-performance composites. A successful melt impregnation method has been developed that results in the production of continuous carbon fiber (CF)-reinforced LCP prepreg tape. Subsequent layup and molding of prepreg into laminates has yielded composites of good quality.Tensile and flexural properties of LCP-CF composites are comparable to those of epoxy-CF composites. LCP-CF composites have better impact resistance than the latter, although epoxy-CF composites possess superior compression and shear strength. LCP-CF composites have good property retention until 200°F (67% of room temperature value). Above 200°F, mechanical properties are found to decrease significantly. Experimental results indicate that the poor compression and shear strength may be due to the poor interfacial adhesion between the matrix and carbon fiber.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 32 (1986), S. 5245-5245 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 15 (1989), S. 31-37 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Some results are reported on the alkyllithium-initiated polymerization of butadiene in cyclopentane in presence of 2,′2-bis(4,4,6-trimethyl-1,3-dioxane). The effect of this lithium chelating agent on one-unit model active centres is also reported. Comparisons are made with another highly efficient polymer structure modifier, 1,2-dipiperidinoethane. Conclusions are reached on the reasons why both are particularly effective in inducing the formation of polydienes having extremely high vinyl content.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 2 (1988), S. 105-109 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 14 (1989), S. 46-52 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Coatings are applied to particulate materials to enhance surface properties while retaining desired bulk properties. Characterization of such coatings presents a challenge. In this paper we present an example of a particle surface analysis and assess how factors such as roughness and coating thickness distributions affect quantitative conclusions. Silica coatings were deposited from aqueous solution on to α-alumina particles of 150 nm average size. Transmission electron microscopy, x-ray photoemission spectroscopy and secondary ion mass spectrometry/depth profiling were used to analyze coatings of thicknesses of tens of nanometers to submonolayer. The three techniques were in excellent agreement in the thickness ranges where they overlapped. XPS does not allow assessment of the uniformity or thickness distribution of the coatings. However, depth profiles are quantitatively consistent with a model of random attachment of the silica units to the particle surface during growth, with no preference for the uncoated alumina surface over the previously deposited silica.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0749-1581
    Keywords: NMR ; LIS ; Amiodarone derivatives ; O-trans/O-cis equilibrium ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A LIS investigation of analogues of amiodarone containing the 3-benzoyl-2-butylbenzofuran system has been performed, utilizing the pseudo-contact shifts of all the proton and carbon nuclei in the molecules. The 13C diamagnetic shifts were removed by use of La(fod)3 and the pseudo-contact shifts were analysed to obtain the conformations in solution of these molecules.In 3-(2,6-dibromobenzoyl)-2-butylbenzofuran (1), the ortho bromo substituents produce sufficient steric hindrance so as to enable the separate O-trans and O-cis conformers to be observed at room temperature.Thus the LIS analysis was performed on both conformers separately. In each case good solutions (Rx 〈5%) were obtained for the conformations in which the benzofuran and carbonyl groups are coplanar and the phenyl group orthogonal to this plane. This was achieved using an unsymmetrical model of the lanthanide complexation to the carbonyl group in which the different spatial environment of the oxygen lone pairs is allowed for in the refinement procedure.In 3-(3,5-diiodobenzoyl)-2-butylbenzofuran (2), in which there is no evidence of conformation isomerism in the NMR spectrum down to -100 °C, the analysis of the LIS data on the basis of a rapidly interconverting mixture of conformers analogous to those of 1 did not produce a satisfactory result. In contrast, analysis on the basis of a single conformation in which the phenyl group is coplanar with the carbonyl group and the benzofuran moiety is twisted out of this plane gave a satisfactory solution for an angle of twist of ca 90°. Owing to the long time scale of the NMR experiment, the LIS results are also consistent with a rapidly interconverting equilibrium between two non-planar conformations in which the average angle of twist of the benzofuran group is ca 90°. This intriguing result can be rationalized by steric considerations and molecular mechanics calculations which indicate that, in the absence of any abutting ortho substituents on the phenyl group, coplanarity of the carbonyl group and the 2-alkylbenzofuran moiety is less favoured energetically than coplanarity of the carbonyl and the phenyl groups. The slightly greater intrinsic torsional barrier of the carbonyl and benzofuran parts is more than compensated for by the increased steric interactions of the carbonyl with the 2-alkyl and 4-hydrogen groups of the benzofuran in the planar form.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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