排序方式: 共有6条查询结果,搜索用时 15 毫秒
1
1.
The intermediate-temperature creep response of single-crystal Ni 3 Al(Ta) has been investigated along both [ ] and [001] axial orientations. The effect of the existing deformation structure (i.e. pre-straining) on the [ ] creep response was reported. The creep responses of virgin specimens and specimens prestrained at room temperature (RT) and 520°C are compared. In order to compare the dislocation structures prior to creep, the microstructure of specimens which had been deformed at a constant strain rate at RT and 520°C, but not subjected to creep, was also examined. Creep curves show that the temperature of pre-strain influences the subsequent creep properties. The primary creep response, like the yielding response, appears to be controlled by the kink size distribution, while the secondary creep response is thought to be controlled by the kink separation (or the length of the Kear-Wilsdorf locks). Specimens crept along [ ] display steady state creep properties and rectangularly oriented [ ](010) dislocations, while a virgin specimen crept along [001] displays an increasing secondary creep rate (inverse creep) and d110 ¢{100}-type dislocations. Inverse creep along [001] is thought to be the result of an increasing density of edge kink octahedral sources where there is little resolved shear stress on the cube planes. 相似文献
2.
Marina Yamamoto Raynbird Dr. Filipa Silva Harry Smallman Dr. Shaista S. Khokhar Dr. Daniel Neef Dr. Gareth J. S. Evans Prof. Dr. Thomas Wirth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(38):8363-8367
A short total synthesis of ajoene, (E,Z)-4,5,9-trithiadodeca-1,6,11-triene 9-oxide, has been achieved over six steps. In addition, a continuous flow synthesis under mild reaction conditions to (E,Z)-4,5,9-trithiadodeca-1,7,11-triene is described starting from simple and easily accessible starting materials. Over four steps including propargylation, radical addition of thioacetate, deprotection, and disulfide formation/ allylation, the target product can be obtained at a rate of 0.26 g h−1 in an overall yield of 12 %. 相似文献
3.
B. E. Sauer J. A. Devlin J. J. Hudson D. M. Kara I. J. Smallman M. R. Tarbutt E. A. Hinds 《Hyperfine Interactions》2013,214(1-3):119-126
We present a summary of the techniques used to test time reversal symmetry by measuring the permanent electric dipole moment of the YbF molecule. The results of a recent measurement (Hudson et al., Nature 473:493, 2011) are reported. We review some systematic effects which might mimic time reversal violation and describe how they are overcome. We then discuss improvements to the sensitivity of the apparatus, including both short term technical enhancements as well as a longer term goal to use laser cooled YbF in the experiment. 相似文献
4.
5.
Zhuang X Le A Steimle TC Bulleid NE Smallman IJ Hendricks RJ Skoff SM Hudson JJ Sauer BE Hinds EA Tarbutt MR 《Physical chemistry chemical physics : PCCP》2011,13(42):19013-19017
The fluorescence spectrum resulting from laser excitation of the A(2)Π(1/2)←X(2)Σ(+) (0,0) band of ytterbium monofluoride, YbF, has been recorded and analyzed to determine the Franck-Condon factors. The measured values are compared with those predicted from Rydberg-Klein-Rees (RKR) potential energy curves. From the fluorescence decay curve the radiative lifetime of the A(2)Π(1/2) state is measured to be 28 ± 2 ns, and the corresponding transition dipole moment is 4.39 ± 0.16 D. The implications for laser cooling YbF are discussed. 相似文献
6.
Machi I.Z. Connell S.H. Major J. Smallman C.G. Sellschop J.P.F. Bharuth-Ram K. Maclear R.D. Doyle B.P. Butler J.E. Scheuermann R. Seeger A. 《Hyperfine Interactions》1999,120(1-8):585-589
This work reports on the promptly forming fraction and the spin relaxation rate of the isotropic muonium (MuT) component in p-type semi-conducting diamond, measured under the condition of illumination. The data are the first such investigations
for diamond. A broad band illumination with wavelengths ranging from 0.5 μm to 3 μm was obtained from a Xenon lamp. The energy
of the photons was sufficient to excite electrons from the valence band to the 0.28 ppm boron impurity band (0.37 eV). The
Transverse Field Muon Spin Rotation (TF-μSR) measurements were conducted as a function of temperature, ranging from 5 K to
300 K. An illumination effect at temperatures below 100 K is observed. It is not yet clear from these data whether the effect
is due to Mut scattering off delocalized holes, which are removed by illumination or whether there is prompt trapping of Mut at boron impurities (passivation) which is affected by illumination.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
1