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81.
A. Berglund T. Buran P.J. Carlson C.J.S. Damerell I. Endo A.R. Gillman V. Gracco R.J. Homer M.J. Hotchkiss A. Lundby M. Macri B.N. Ratcliff A. Santroni T. Tso F. Wickens J.A. Wilson 《Physics letters. [Part B]》1978,73(3):369-374
For the first time, the line reversed reactions π+p→K+Σ+and K?p→π?Σ+ have been studied in the same apparatus. We present the differential cross sections and polarizations over a large t range and at two momenta, 7.0 and 10.1 GeV/c. The differential cross sections as a function of t are shown for the first time to cross over. Going from the lower to the higher momentum, the differences in cross section between the two reactions diminish at low |t| by about a factor 2. We find large polarizations of opposite sign for the two reactions. The momentum dependence, presented in the form of αeff(t) for the t range 0 to ?2 (GeV/c)2, is compared with the expectations from the K1?K7 trajectory. 相似文献
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J. D'Ans G. Dorfmüller J. Großfeld H. Leonhardt Ph. Naoúm A. Berthman G. Jayme R. Korn F. Burgstaller H. Sommer H. Mendrzyk W. Weltzien Karin Windeck-Schulze E. Ristenpart E. Sauer A. Küntzel S. Reissinger W. Esch W. Toeldte H. P. Kaufmann S. Funke W. Halden B. Wurzschmitt H. Thomas E. van Hulle E. Messmer P. Rabe H. van Haasy G. Hamann T. Berglund M. Sartori Gebührenaussehuß für chemische Arbeiten 《Analytical and bioanalytical chemistry》1940,119(11-12):422-425
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Tungsten trioxide reduced at about 1270 K by means of controlled atmospheres (P02 = 3.7 · 10?8 to 1.7 · 10?13 atm) was studied by high resolution transmission electron microscopy, electron diffraction, and X-ray powder diffraction. The accommodation of oxygen loss in the parent WO3 lattice in the range WO3 to WO2.72 was clarified. The results indicate a solid state mechanism. Intergrowth has been found to take place between several of the structural types that occur in this composition range. The intergrowth features include directional changes in shear plane arrays (“swinging shear planes”). Details of the structural variation with the oxygen content are reported. Ordered shear planes on {102} directions were found to stabilize the orthorhombic WO3 parent lattice at room temperature. W24O68 has been prepared in a fairly well-defined state. 相似文献
86.
X Fang KW Ledingham P Graham DJ Smith T McCanny RP Singhal AJ Langley PF Taday 《Rapid communications in mass spectrometry : RCM》1999,13(14):1390-1397
The potential of femtosecond laser time-of-flight mass spectrometry (FLMS) for uniform quantitative analysis of molecules has been investigated. Various samples of molecular gases and vapours have been studied, using ultra-fast ( approximately 50 fs) laser pulses with very high intensity (up to 1.6 x 10(16) Wcm(-2)) for non-resonant multiphoton ionisation/tunnel ionisation. Some of these molecules have high ionisation potentials, requiring up to ten photons for non-resonant ionisation. The relative sensitivity factors (RSF) have been determined as a function of the laser intensity and it has been demonstrated that for molecules with very different masses and ionisation potentials, uniform ionisation has been achieved at the highest laser intensities. Quantitative laser mass spectrometry of molecules is therefore a distinct possibility. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
87.
Electrochemical Measurements of Optogenetically Stimulated Quantal Amine Release from Single Nerve Cell Varicosities in Drosophila Larvae 下载免费PDF全文
Dr. Soodabeh Majdi Dr. E. Carina Berglund Johan Dunevall Dr. Alexander I. Oleinick Prof. Christian Amatore Prof. David E. Krantz Prof. Andrew G. Ewing 《Angewandte Chemie (International ed. in English)》2015,54(46):13609-13612
The nerve terminals found in the body wall of Drosophila melanogaster larvae are readily accessible to experimental manipulation. We used the light‐activated ion channel, channelrhodopsin‐2, which is expressed by genetic manipulation in Type II varicosities to study octopamine release in Drosophila. We report the development of a method to measure neurotransmitter release from exocytosis events at individual varicosities in the Drosophila larval system by amperometry. A microelectrode was placed in a region of the muscle containing a varicosity and held at a potential sufficient to oxidize octopamine and the terminal stimulated by blue light. Optical stimulation of Type II boutons evokes exocytosis of octopamine, which is detected through oxidization at the electrode surface. We observe 22700±4200 molecules of octopamine released per vesicle. This system provides a genetically accessible platform to study the regulation of amine release at an intact synapse. 相似文献
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A. Berglund T. Buran P.J. Carlson C.J.S. Damerell I. Endo A.R. Gillman V. Gracco R.J. Homer M.J. Hotchkiss A. Lundby M. Macri B.N. Ratcliff A. Santroni T. Tso F. Wickens J.A. Wilson 《Physics letters. [Part B]》1975,57(1):100-104
For the first time, the reactions π+p→K+∑+ and K?p→π?∑+ have been studied in the same apparatus. This has been done at an adequately high momentum (10.1 GeV/c) to allow a check of the prediction of exchange degeneracy, that the differential cross sections should be converging at high energy. We have measured the cross section for momentum transfers t between tmin and t = ?0.3 (GeV/c)2. We find that for both reactions the differential cross section shows an exponential fall, with no deviations right in to t =tmin (where some other experiments have shown a dip in the cross section). Furthermore, we find the magnitude of the differential cross sections to be closely similar at t = 0, with a ratio However, the slope for the positive reaction is about 19% steeper than that for the negative reaction. 相似文献