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111.
112.
Gregory Kennedy Cornelia Chilian Radojko Jaćimović Gašper Žerovnik Luka Snoj Andrej Trkov 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(2):555-559
In order to predict the self-shielding effect in neutron activation of non-spherical samples in reactor neutron spectra, it
is important to know whether the neutron field is sufficiently anisotropic to cause significant variations between horizontal
and vertical sample orientation or with orientation relative to the direction towards the reactor core. Metal wires with significant
neutron self-shielding were irradiated in several channels of the SLOWPOKE reactor at Ecole Polytechnique Montreal and the
TRIGA reactor at the Jožef Stefan Institute. In all cases, the amount of thermal or epithermal self-shielding was found to
be identical, within the experimental uncertainty, regardless of the orientation of the wire, indicating that the neutron
field is essentially isotropic. Models used to predict neutron self-shielding need to be adjusted accordingly. In our Monte
Carlo model, the tube-shaped neutron source was moved back into the moderator and reflecting materials near the sample location
were included, which produced an isotropic neutron field at the sample location. 相似文献
113.
Thomas Apel Dominique Leguillon Cornelia Pester Zohar Yosibash 《Comptes Rendus Mecanique》2008,336(8):629-635
The elastic solution in a vicinity of a re-entrant wedge can be described by a Williams like expansion in terms of powers of the distance to a point on the edge. This expansion has a particular structure due to the invariance of the problem by translation parallel to the edge. We show here that some terms, so-called primary solutions, derive directly from solutions to the 2-D corner problem posed in the orthogonal cross section of the domain. The others, baptized shadow functions, derive of the primary solutions by integration along the axis parallel to the edge. This 3-D Williams expansion is shown to be equivalent to the edge expansion proposed by Costabel et al. [M. Costabel, M. Dauge, Z. Yosibash, A quasidual function method for extracting edge stress intensity functions, SIAM J. Math. Anal. 35 (5) (2004) 1177–1202]. To cite this article: T. Apel et al., C. R. Mecanique 336 (2008). 相似文献
114.
115.
Cornelia Lanz Moritz Schlötter Nele Klinkenberg Patricia Besirske Prof. Dr. Sebastian Polarz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):8987-8991
Amphiphiles alter the energy of surfaces, but the extent of this feature is typically constant. Smart systems with amphiphilicity as a function of an external, physical trigger are desirable. As a trigger, the exposure to a magnetic field, in particular, is attractive because it is not shielded in water. Amphiphiles like surfactants are well known, but the magnetic response of molecules is typically weak. Vice-versa, magnetic particles with strong response to magnetic triggers are fully established in nanoscience, but they are not amphiphilic. In this work colloids with Janus architecture and ultra-small dimensions (25 nm) have been prepared by spatial control over the thiol-yne click modification of organosilica-magnetite core–shell nanoparticles. The amphiphilic properties of these anisotropically modified particles are proven. Finally, a pronounced and reversible change in interfacial stabilization results from the application of a weak (<1 T) magnetic field. 相似文献
116.
117.
Homeotropically aligned nematic liquid crystals doped with azo-dye were subjected both to a linear polarized light of a He–Ne laser and to a magnetic field perpendicular to the incident light beam. We found that the emerging light was elliptically polarized when using magnetic field strengths higher than the threshold value for the magnetic Freedericksz transition. The light transmission, the rotatory power (induced by azo-dye) and the ellipticity varied quasiperiodically when increasing magnetic field strength. The number and positions of maxima and minima depend on the cell thicknesses. Changes in the phase difference between the emergent ordinary and extraordinary rays were computed from the experimental data and the magnetic field dependence of the birefringence was determined. 相似文献
118.
Raluca Nicoleta Darie Mihai Brebu Cornelia Vasile Marek Kozlowski 《Polymer Degradation and Stability》2003,80(3):551-566
Binary isotactic polypropylene (IPP)/polyamide 6 (PA6) and ternary IPP/PA6/ethylene–propylene diene terpolymer (EPDM) blends in various ratios were obtained in a Haake Rheocord mixer. Processing behaviour was changed in the presence of IPP functionalized with bismaleimide (BMI), maleic anhydride (MA) and acrylic acid (AA) as reactive compatibilizing agents. The thermal and thermo-oxidative behaviour of blends was studied by differential scanning calorimetry and thermogravimetry. The functionalized IPPs modify the crystallinity degree and the decomposition behaviour of both IPP and PA6 as a result of chemical reactions of functional groups with those of the PA6. The changes depend on the IPP/PA6 or IPP/PA6/EPDM ratio, the chemical nature and amount of the functionalized IPP. On the basis of the processing and thermal data one can conclude that the compatibilizing agent effect increases in the following order: IPP-AA 相似文献
119.
F. Geiger R. Stolle G. Marowsky M. Palenberg B. U. Felderhof 《Applied physics. B, Lasers and optics》1995,61(2):135-141
We present a new technique to determine the complex-valued tensor components of the nonlinear surface susceptibility
s
(2)
of isotropic adsorbate layers. It is based on a change of the state of the fundamental polarization by rotation of a quarter-wave plate. We verify the theoretical predictions by measurements on a Langmuir-Blodgett film of a highly nonlinear hemicyanine dye in total reflection geometry. The obtained second-harmonic rotation pattern is analyzed in Fourier components, which are related to the absolute value and relative phase of the tensor components of the surface susceptibility. We compare the obtained results with separate measurements in which a half-wave plate is used to rotate the fundamental polarization. Our results are confirmed by an additional interference experiment. The method presented here allows the single-valued determination of
s
(2)
with measurements at only one angle of incidence, in contrast to the half-wave-plate technique. 相似文献
120.
The sequential reaction of the amino(trimethylsilyl)carbene complex [(CO)5W=C(NH2)C≡CSiMe3] ( 1 ) with nBuLi and [I‐Fe(CO)2Cp] affords the C(carbene)‐N bridged heterobinuclear complex [(CO)5W=C{NHFe(CO)2Cp}C≡CSiMe3] ( 2 ). Desilylation of 1 is achieved by treatment with KF in THF/MeOH. From the reaction of the resulting complex [(CO)5W=C(NH2)C≡CH] ( 3 ) with nBuLi and [I‐Fe(CO)2Cp] two binuclear WFe compounds in a ratio of approximately 1:1 are obtained: the C(carbene)‐C≡C bridged complex 4 and the C(carbene)‐N bridged complex 5 . Repetition of the deprotonation/metallation sequence yields the trinuclear WFe2 complex 6 . One Fe(CO)2Cp fragment in 6 is bonded to the amino group and the other one to the terminal carbon atom of the ethynyl substituent. The analogous reaction of 3 with nBuLi and [Br‐Ni(PMe2Ph)2Mes] gives a ca. 1:1 mixture of two heterobinuclear complexes ( 7 and 8 ). Complex 7 is bridged by the C(carbene)‐C≡C and complex 8 by the C(carbene)‐N fragment. Subsequent reaction of 7 with BuLi and [Br‐Ni(PMe2Ph)2Mes] finally affords the trinuclear WNi2 complex 9 related to 6 . The solid‐state structure of 2 is established by an X‐ray diffraction analysis. The spectroscopic data of the bi‐ and trinuclear complexes indicate electronic communication between the metal centers through the bridging group. 相似文献