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1.
The sex pheromone components of the two sibling species of the dingy cutworm that occur on the prairies of western Canada were identified in abdomen-tip extracts from calling female moths. Three monounsaturated acetates, (Z)-7-dodecenyl acetate, (Z)-9-tetradecenyl acetate, and (Z)-11-hexadecenyl acetate, are common to both species in ratios of 100133 for species A and 0.30.5100 for species B. The most effective synthetic blends for the attraction of male moths in the field consisted of these three components in ratios of 1010 at 8.8g/lure for species A and 112000 at 500g/lure for species B. The addition of Z5-12Ac to either blend reduced the catches and the addition of Z7-12OH orZ11-16OH to the three-component blend reduced the catches of species B males. The species are morphologically indistinguishable, but the identity of the males attracted to the synthetic blends could be confirmed by their antennal responses to a test blend of the three components using a GC-EAD system. Both synthetic attractant blends are competitive with females and will be useful for studying the distribution, biology, and relative abundances of the two species.Contribution no. 3879005 of the Lethbridge Research Station.  相似文献   

2.
Conclusions During the sintering process of beta-alumina obtained using the method of plasmochemical synthesis, the structural transformation occurs and it is accompanied by the separation of the excess Na2O and the formation of an intergranular meltlike phase that is saturated with sodium and is characterized by high dielectric properties.The quantity of the meltlike phase and the magnitude of the /( + ) ratio determine the degree of stabilization (stability) and the final resistivity of the material and depend on the initial chemical composition and the heating rate maintained during the sintering process.It was shown that when the duration of residence of the material in the hot zone of the furnace is increased or when the specimens sintered maintaining high heating rates are subjected to additional heat treatment, one observes the occurrance of the reverse structural transformation that is characterized by an increase of the phase ratio /( + ) 1, a reduction in the quantity of the meltlike phase right up to its complete disappearance, and a decrease of the electrical resistivity of the material.In the materials having a large excess quantity of sodium oxide, the process of crystallization of the intergranular NaAlO2 phase occurs simultaneously with the second phase transformation.The best ceramic and electrophysical parameters were obtained when sintering the material contained 7.9% Na2O.Translated from Ogneupory, No. 3, pp. 13–18, March, 1990.  相似文献   

3.
Strontium ferrates and cobaltates with compositions SrFeO3- (0.060.40) and SrCoO3- (0.040.30) were synthesized. The dependence of the oxygen electrode properties on the value was examined in 1 mol dm–3 KOH solution. In the SrFeO3- series, the samples with 0.24<<0.29, showed the highest activity in both oxygen evolution and reduction reactions. In contrast, no strong dependence on the value was observed in SrCoO3-, which also showed a high catalytic activity for oxygen evolution.  相似文献   

4.
Competitive field tests with -fluorinated analogs of compounds III and IV (III--F and IV--F, respectively) of the boll weevil,Anthonomus grandis Boh., aggregation pheromone showed these compounds, when combined with the other pheromone components [(±)-I and II], to be as attractive as grandlure [(+)-I, II, and III+IV]. Dose-response curves constructed from electroantennograms of male boll weevils to serial stimulus loads of III, IV, III--F, IV--F, and the corresponding acyl fluorinated analogs (III-acyl-F and IV-acyl-F) showed the -fiuorinated analogs to be as active as the pheromone components (threshold=0.1 g), while the acyl fluorinated analogs had a 10-100 x higher threshold (=1-10 g). Single-neuron recordings showed that IV neurons and II neurons (Dickens, 1990) responded to IV--F and III--F, respectively, while IV-acyl-F and III-acyl-F were inactive. Since a previous study showed compounds I, II, and IV to be essential for behavioral responses in the field, it seems likely that the activity of the -fluorinated analogs observed here is due to the stimulation of IV neurons by IV--F as indicated in single neuron recordings.  相似文献   

5.
Electroantennogram (EAG) responses of maleRhopobota naevana (Hübner), the blackheaded fireworm, to all of the monoene straightchain 12- and 14-carbon alcohols and acetates implicated (Z)-11-tetradecenl-1-ol (Z11–14OH) and its acetate (Z11–14Ac) as sex pheromone components.Z11–14Ac produced the strongest EAG response of all compounds tested. Gas chromatography-mass spectrometry (GC-MS) analysis of extract of female sex pheromone glands (SPG) confirmed the presence ofZ11–14OH (125 pg/female) andZ11–14Ac (600 pg/female) (all other monoenes had different retention times). In field tests, traps baited withZ11–14OH alone captured males, but traps baited withZ11–14Ac alone did not. Traps baited with a combination ofZ11–14OH andZ11–14Ac in various ratios did not produce better trap catches thanZ11–14OH alone. (Z)-9-Dodecen-1-ol acetate (Z9–12Ac), reported by others to be a field attractant, did not produce trap catch in our tests, but in combination withZ11–14 OH (982 in septa corresponding to 95:5 in vapor,Z11–14OH toZ9–12AC) produced a sevenfold increase in catch overZ11–14OH alone. IfZ9–12AC had been present in extract of SPG at 2–5% ofZ11–14OH, it would not have been detected in our GC-MS experiment. Rhopobota naevana (Hübner) Lepidoptera: Tortricidae: Olethreutinae.  相似文献   

6.
Summary de electrical conductivity at surface of -irradiated polyaniline (PAn) has been studied. EPR spectroscopic results indicate that the variation of spin concentration is consistent with the increase of de. Electrical conductivity (de) versus temperature (T) characteristics of unirradiated and irradiated PAn were performed, which demonstrate that the unirradiated curve can fit to lndeT1, while the irradiated curve fit to lndeT1/4.  相似文献   

7.
A highly dealuminated H-mordenite (H-M) catalyzed the selective isopropylation of biphenyl to 4,4-diisopropylbiphenyl (4,4-DIPB). The high selectivity is ascribed to the shape-selective catalysis in mordenite pores. The selectivity of 4,4-DIPB decreased during the isopropylation of biphenyl due to isomerization of 4,4-DIPB under low propylene pressure. The increase of propylene pressure suppressed the isomerization in the isopropylation. 4,4-DIPB itself was isomerized over highly dealuminated H-M under low propylene pressure.  相似文献   

8.
The convective regime of filtration combustion of energetic materials in a cocurrent flow of their combustion products is studied using a model with extremely simplified kinetics and heat transfer, which shows instability of the process. It is shown that the more accurate twotemperature model describes a steadystate regime. In this regime, the gas temperature on the hot boundary of the heating zone is well below the combustion temperature, and the solidphase temperature is well below the temperature proposed in recent studies on this topic. It is pointed out that the twotemperature approach is unjustified and intragranular nonisothermicity must be taken into account for convective regimes. It is shown that the threetemperature model, which takes into account this effect, does not give a stable steadystate solution.  相似文献   

9.
Conclusions It is proposed to use the equation of a lemniscate, or the Cassini curve, to determine the destructive stress at break for cellulose films in any direction. Thereupon, to determine , it is necessary to know the destructive stress along two basic directions (0 and 90).To obtain cellulosic films which are isotropic in plane, a necessary and sufficient condition is 0=90.Translated from Khimicheskie Volokna, No. 6, pp. 34–35, November–December, 1987.  相似文献   

10.
V. Percec  S. Okita  J. Bae 《Polymer Bulletin》1992,29(3-4):271-276
Summary The synthesis and Ni(0) catalyzed homocoupling polymerization of 4,4-bis[5-(trifluoromethanesulfonyloxy)-2-biphenylyl]-1, 1-binaphthyl (9) are described. This polymerization reaction produces a soluble polyarylene containing alternating 4,4-(1,1-binaphthyl) and 4,4-(3,3-diphenyl)biphenyl structural units.  相似文献   

11.
Summary Molecular scattering functions at intermediate scattering vectors, of =(4/ sin/2) in the range 0.03 to 1.0Å–1, are found to be extremely sensitive to the local configurations of polymer chains in both semicrystalline and amorphous states. Available experimental results of intermediate angle neutron scattering (IANS) from melt-crystallized polyethylene and isotactic polypropylene provide compelling evidence that adjacent re-entry is rare. The rotational isomeric state model satisfactorily accounts for IANS and chain dimensions of polycarbonate in the amorphous state.  相似文献   

12.
Soldiers of free-ranging termites of the genusLacessititermes (Isoptera, Nasutitermitinae) secrete from their frontal glands a mixture of monoterpenes, sesquiterpenes, and diterpenes.Lacessititermes ransoneti, L. laborator, andL. species A produce species-specific secretions, the composition being most complex forL. laborator. Apart from known mono- and dihydroxytrinervitadienes, the following new diterpenes were isolated and tentatively assigned as trinervita-1(15),8(19)-dien-2,3,9,14-tetraol 2,3,14-O-triacetate, trinervita-1(15),8(19)-dien-2,3,9,14-tetraol 2,3,14-O-triacetate, 2,3,9, 14-tetraacetoxy-1 (15), 8(19)-trinervitadiene, and 2,3,11,13-tetraacetoxy-1(15),8(19)-trinervitadiene. Data on intragenus chemical variations were subjected to canonical discriminant analysis and genetic distances among the species were calculated to depict intragenus identities and affinities.  相似文献   

13.
Summary The electrochemical properties of poly(4,4-diphenylamine methylenes) and poly(4,4-diphenylimine methines) were investigated by cyclic voltammetry. A dehydrogenation reaction occured when poly(4,4-diphenylamine methylenes) underwent a electrochemical reaction and transformed to poly(4,4-diphenylimine methines). The fully oxidized poly(4,4-diphenylimine methines) had the electrochemical band gaps of 1.60–1.72 eV, which were found to significantly smaller than those of the fully reduced poly(4,4-diphenylamine methylenes).  相似文献   

14.
The isothermal cure of an epoxy-novolac molding compound was studied by means of Fourier-transform infrared spectroscopy (FTIR) and dielectrometry (DE). Results obtained were compared with previous differential scanning calorimetric (DSC) observations. The behavior of epoxide conversion (FTIR) measured via FTIR was found similar to (but not exactly coinciding with) the extent of cure (DSC) determined previously by means of DSC. As for the DE analysis, directly measurable properties such as permittivity () and loss factor () varied in a complicated manner during the course of cure, showing strong dependence on both temperature and frequency. Other dielectric parameters (such as ionic conductivity, relaxed permittivity, and characteristic relaxation time) previously suggested in the literature as suitable for cure monitoring purposes were found difficult to determine within the limited frequency range (100 to 104 Hz) here. With some arbitrariness, the relative drop in log (at 100 Hz) was taken as an index (DE) for the extent of cure. It was observed that DE behaves in a manner similar to FTIR and DSC Comments on the application of these three techniques in the characterization of thermosetting systems were given.  相似文献   

15.
Silphinene Sesquiterpenes as Model Insect Antifeedants   总被引:3,自引:0,他引:3  
Silphinene sesquiterpenes are established chrysomelid antifeedants. In this work, nine silphinene analogs, 11-acetoxy-5-angeloyloxysilphinen-3-one (1), 11-acetoxy-5-tigloyloxysilphinen-3-one (2), 11-acetoxy-5-iso- butyryloxysilphinen-3-one (3), 11-hydroxy-5-angeloyloxysilphinen-3-one (4), 11,5-dihydroxysilphinen-3-one (5), 11,5-diacetoxysilphinen-3-one (6), 5,11-diisobutyryloxysilphinen-3-one (7), silphinen-3,5,11-trione (8), and O-methyl-5-epicantabrenolic acid methyl ester (10), and a presilphiperfolane sesquiterpene (9) were tested against several divergent insect species, including the lepidopteran Spodoptera littoralis, the chrysomelid Leptinotarsa decemlineata, and five aphid species, and their antifeedant effects were compared with those of picrotoxinin, a GABA-antagonist, and thymol, an allosteric modulator for insect GABA receptors. All insects tested responded to at least one silphinene analog and/or GABA antagonist. Compound 3 and thymol were effective antifeedants against all species tested except S. littoralis, with varying potencies according to their feeding ecologies. The toxicity of these compounds was species-dependent and did not correlate with their antifeedant effect.  相似文献   

16.
Mass and momentum transfer at a wall in liquid-particle systems are studied with a two-dimensional model which consists of fixed spherical turbulence promoters arranged in a simple cubic lattice in a rectangular channel. Local values of the mass transfer coefficient and shear stress at a wall of the channel have been measured at identical locations. The results show that there are large differences between the local values but their distribution along the transfer surface is reproduced identically. The dependence of these local values on each other allows one to obtain a general relationship between overall mass and momentum transfer as well as a correlation of mass transfer results for exchange between a wall and a flowing liquid in a fixed bed of particles.Nomenclature a g particle specific area - a coefficient in expression s=a q (q>0) - a, b coefficients in expressionJ M=a(Re) –b - d p particle diameter - d microelectrode diameter - D molecular diffusion coefficient - h K,h B constants in Ergun equation - J M=(¯k/u/)(Sc) 2/3 Colburnj-factor - k local mass transfer coefficient - k local mass transfer coefficient in inert wall - ¯k overall mass transfer coefficient - L length of the transfer surface - q exponent in expressions=a q - (Re)=(ud p)/[v(1-)] modified Reynolds particle number - (Sc)=v/D Schmidt number - s, ¯s velocity gradients at the wall - u superficial liquid velocity - coefficient in Equation 1 - characteristic length - bed porosity - F fluid density - dynamic viscosity - kinematic viscosity - shear stress at the wall - P/L fluid pressure gradient  相似文献   

17.
Summary The synthesis of novel telechelic monodispersed nonconjugated dienes from commercially available , -dithiols and dienes is presented. The batch reaction produced a polydispersed. mixture separable with difficulty whereas a dropwise addition of dithiol onto an excess of , -diene in the presence of peroxide led selectively and quantitatively to the addition product: diene-dithiol-diene.  相似文献   

18.
Summary Asymmetrically disubstituted poly(2-isopropoxy-5-methoxy-1,4-phenylene-vinylene), PIMPV, was prepared in thin films via organic-soluble precursor polymer method. These polymer films could be easily stretched up to 7 times, and the drawn films of the PIMPV could be doped with FeCl3 and I2 to give conductivities of 26.9 and 11.3 Scm-1, respectively. The third-order nonlinear optical susceptibility of the polymer was determined using third harmonic generation(THG) method at 1907 nm, fundamental wavelength. Measured (30) (-3: , , ) value was 3.7x10-12 esu.  相似文献   

19.
Four acetates,Z-5-decenyl acetate,Z-5-,Z-7-, andZ-9-dodecenyl acetates, in microgram ratios of 120021 or 120062 were excellent, specific sex pheromone blends for capturing male redbacked cutworm moths in cone traps. Blends in ratios of 120021 and 220021 at 1000 g/ rubber septum dispenser remained highly effective for 6 weeks under field conditions. The essential minor components,Z-5-decenyl,Z-7-, andZ-9-dodecenyl acetates, became inhibitory at concentrations of about 10% in the blends, and this may be an important general phenomenon in lepidopteran pheromones. Blends involving a parapheromone,Z-5-undecenyl acetate, withZ-5-,Z-7-, andZ-9-dodecenyl acetate, in microgram ratios of 820021 or 2020062 were also excellent specific attractants for this species. TheZ-8-dodecenyl acetate had no obvious effect on the attraction of the redbacked cutworm males.  相似文献   

20.
Summary Polystyrene macromonomers with terminal 1,1-diphenylethylene functionality were prepared by the reaction of one equivalent of poly(styryl)lithium with 1,4-bis (l-phenylethenyl)benzene (PDDPE). The macromonomer functionalities were determined by 1H NMR [(vinyl CH2)=5.4 ppm] and UV spectroscopy (max=260 nm). The stoichiometric linking reaction of poly(styryl)lithium (Mn=15.3x103 g/mol) with an -1,1-diphenylethylene-terminated polystyrene macromonomer (Mn=5.4x103 g/mol) followed by addition of styrene monomer has been used to prepare a hetero three-armed, star-branched polymer with Mn=5.8x104 g/mol (5,400-15,300-37,300). The g value ([]b/[]l) was equal to 0.92.  相似文献   

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