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41.
Analysis of the hornet’s hemolymph revealed the presence of C16 and C18 fatty acids (70%), which were accompanied by minor quantities (ranging from 0.1% to 0.6%) of the following acids: C10∶0, C11∶0, C12∶0, C13∶0, C14∶0, C15∶0, C16∶0, and C17∶0. The hemolymph of the queen larvae contained more C18∶1 than the hemolymph of the worker larvae, and the percentage of C16∶1 was higher in the fat body and the midgut than in the hemolymph. The significance of these results is discussed. 相似文献
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43.
Phase relations in the systems SrO-Y2O3-CuO-O2 and CaO-Y2O3-CuO-O2 at 1173 K were estab-lished by equilibrating different compositions in flowing oxygen gas at a pressure of 1.01 × 105 Pa. The quenched samples were examined by optical microscopy, X-ray diffraction (XRD), energy dis-persive analysis of X-rays
(EDAX), and electron spin resonance (ESR). In the system SrO-Y2O3-CuO-O2, except for the limited substitution of Y3+ for Sr2+ ions in the ternary oxide Sr14 Cu24O41, no new quaternary phase was found to be stable. The compositions corresponding to the solid solution Sr14-xYxCu24O41 and the compound SrCuO2+δ lie above the plane containing SrO, Y2O3, and CuO, displaced towards the oxygen apex. However, in the system CaO-Y2O3-CuO-O2 at 1173 K, all the condensed phases lie on the plane containing CaO, Y2O3, and CuO, and a new quaternary oxide YCa2Cu3O6.5 is present. The quaternary phase has a composition that lies at the center of the non-stoichiometric field of the analogous
phase YBa2Cu3O7-δ in the BaO-Y2O3-CuO-O2 system. The com-pound YCa2Cu3O6.5 has the tetragonal structure and does not become superconducting at low temperature. Surprisingly, phase relations in the
three systems CaO-Y2O3-CuO-O2, SrO-Y2O3-CuO-O2, and BaO-Y2O3-CuO-O2 are found to be quite different. 相似文献
44.
Electrical (solder resistivity and solder joint resistance) and mechanical (tensile strength and shear strength of solder
joints) parameters of the binary eutectic Sn-Ag and two alloys close to the ternary eutectic Sn-Ag-Cu composition were investigated.
The four-probe technique was used for the measurement of electrical parameters. Special equipment was constructed for the
tensile strength measurements and also for determination of the shear strengths of solder joints between a typical circuit
component and a Cu contact on a printed circuit board (PCB). It was found that electrical and mechanical properties of the
three alloys studied are comparable to data in the literature for traditional Pb-Sn solders. A joint resistance below 0.3
mΩ (Ω=ohm) and shear strength of above 20 MPa were found for an individual solder joint between a circuit component (in the
current study a “jumper” resistor) and a copper surface on a PCB. 相似文献
45.
Data-intensive problems challenge conventional computing architectures with demanding CPU, memory, and I/O requirements. Experiments with three benchmarks suggest that emerging hardware technologies can significantly boost performance of a wide range of applications by increasing compute cycles and bandwidth and reducing latency. 相似文献
46.
Cylindrical fibre actuators have been constructed by a coextrusion method using a thermoplastic polyurethane wall and a conductive grease filler. These actuators may be operated as single fibres or bundled together as actuating ropes. Key results include the validation of Carpi’s wall pressure model [F. Carpi, D.D. Rossi, Dielectric elastomer cylindrical actuators: electromechanical modelling and experimental evaluation, Mater. Sci. Eng. C-Biomimetic Supramol. Syst. 24 (2004) 555–562] and the proof-of-concept demonstration of a technique that can be used for producing inexpensive dielectric elastomer actuators on an industrial scale. 相似文献
47.
We characterize the amount of alternation between blocks of Boolean quantifiers (having both existential and universal), blocks
of real existential quantifiers, and blocks of real universal quantifiers that can be decided in parallel polynomial time
over the reals. We do so under the assumption that blocks have a uniform bound on their size, both for the case of this bound
to be polynomial and constant. On the way towards this characterization we prove a real version of Savitch’s Theorem. 相似文献
48.
We show how energy-filtered convergent-beam electron diffraction (EFCBED) patterns can be used to determine the chemical composition of buried semiconductor strained quantum wells. Our method is based on a quantitative analysis of the intensities of high-order Bragg lines in the transmitted disc of EFCBED patterns taken from plan-view samples. This analysis makes it possible to determine the displacement vector R introduced between the top and bottom parts of the matrix by the deformation of the quantum well and consequently to determine its composition. This is illustrated in the case of an In(x)Ga(1-)(x)As quantum well buried in a GaAs matrix. A detailed analysis of the effect of experimental parameters on Bragg lines intensity is performed. In particular, the importance of the choice of the diffraction vector is pointed out. The relative uncertainty on the measurement of the indium content x is found to be lower than 5% and a possible occurrence of slight compositional fluctuations in the (001) growth plane is pointed out. 相似文献
49.
50.