Many materials exhibit various magnetic phenomena as a function of magnetic field, temperature and/or pressure. Usually, bulk magnetic measurements provide first information on the magnetic state of the material by measuring their response on the applied magnetic field. However, it is necessary to investigate materials also on a microscopic scale. This is often done by means of neutron scattering. In this contribution we discuss basic ideas of this method and we report on few experimental results obtained with a split-pair coil 14.5 T superconducting magnet which can be combined with dilution stick offering temperatures as low as 30 mK and/or with a small clamped-type pressure cell which offers pressure up to 1.0 GPa. 相似文献
Results of the first elastic K
So
regeneration experiment on carbon, using magnetic spark chamber spectrometer, are presented in the beam momentum interval 10p50 GeV/c. The d ifferentia cross section d/dt is reconstructed in the range 0·0025–t0·02 (GeV/c)2 and its slopeB is found to be momentum independent with an average valueB=(65±11) (GeV/c)–2. The results are in agreement with the calculations using the coherent production model. 相似文献
Implications of Weinberg's algebraic relations when only p-wave pions are taken into account are investigated. It is shown that decay rates and mass spectra of hadrons assigned to certain classes of unitary irreducible representations of theSU(4) group are in a strong disagreement with experimental data. 相似文献
Dehalogenation of halogenated anilines by action of powdered aluminium–nickel alloy in aqueous alkaline solution at room temperature
has been studied. The reaction course was monitored by means of 1H nuclear magnetic resonance (NMR) spectroscopy. The rates of dehalogenation of 4-bromo-, 4-chloro-, 4-fluoro- and 3-chloroaniline
were compared under conditions of minimum necessary excess of Al–Ni alloy as reducing agent in edetane buffer medium at pH
10.9. The dehalogenation rates of halogenated anilines decreased in the following order: 3-chloroaniline > 4-bromoaniline ≥ 4-chloroaniline > 4-fluoroaniline.
On the basis of the results obtained in buffers, the dehalogenation method of aqueous solutions of halogenoanilines was verified
using NaOH as the base. 相似文献
Laser desorption ionization using time-of-flight mass spectrometer afforded with quadrupole ion trap was used to study As2Ch3 (Ch = S, Se, and Te) bulk chalcogenide materials. The main goal of the study is the identification of species present in the plasma originating from the interaction of laser pulses with solid state material. The generated clusters in both positive and negative ion mode are identified as 10 unary (Sp+/– and Asm+/–) and 34 binary (AsmSp+/–) species for As2S3 glass, 2 unary (Seq+/–) and 26 binary (AsmSeq+/–) species for As2Se3 glass, 7 unary (Ter+/–) and 23 binary (AsmTer+/–) species for As2Te3 material. The fragmentation of chalcogenide materials was diminished using some polymers and in this way 45 new, higher mass clusters have been detected. This novel approach opens a new possibility for laser desorption ionization mass spectrometry analysis of chalcogenides as well as other materials.
Hybrid organic-inorganic coatings and free-standing films made from [3-(glycidyloxy)propyl]trimethoxysilane, amino-terminated poly(oxypropylene) (Jeffamine D-230), colloidal polyaniline nanoparticles and, in some cases, colloidal nanosilica were prepared and characterized. HCl or 4-methylbenzene-1-sulfonic acid were used as catalysts for the sol-gel process and pH tuning, water-propan-2-ol mixture as a solvent. Electrical and mechanical properties and surface morphology of films were studied. The coatings were blue and non-conducting, or green and conducting, depending on preparation conditions. They have a smoother surface than in-situ polymerized polyaniline films. 相似文献
We have studied the unusual low-temperature magnetic phase of Er2Ni2Pb using powder neutron diffraction measurements in zero field down to 460 mK. Our previous neutron diffraction experiments
down to 1.5 K showed that magnetic Bragg reflections seen in Er2Ni2Pb can be indexed by several propagation vectors that partially coexist. All the incommensurate propagation vectors seemed
to disappear in the low temperature limit. The present study, however, shows that reflections belonging to the propagation
vector q’ = (0.47 0 1/2) do not disappear but remain present down to 460 mK. This highly unexpected result suggests that the magnetic
structure described by this propagation vector might not be a simple sine-wave modulation. One interesting possibility here
is a spin-slip structure as the ground state. 相似文献
Miniature silicon photodiodes have been tested for utilization in radiotherapy. Their use in the treatment of ca laryngis is described. The actually given dose was monitored during irradiation. Treatment plan or the setting up of the entrance fields was modified according to the response of the diode. This method seems to be a useful tool for checking both the treatment plan and appropriate setting up of the patient in treatment position. 相似文献