[en] Published in summary form only

[en] Neutron diffraction measurements of a triangular lattice antiferromagnet CsCuCl₃ have been done in a pulsed high magnetic field up to 14T. The field applied parallel to the c-axis and it is observed that the reflection intensity at (1/3 1/3 0.085), which corresponds to the low field magnetic structure, abruptly decreases at Bc = 10T, where the magnetization shows a small jump. Above Bc, a new reflection at (1/3 1/3 0) appears. These results are consistent with a model that a new type of magnetic phase transition occurs due to the quantum effect. (author)

[en] Present neutron scattering and magnetization measurements reveal that La₂NiO_4+δ provides lots of varieties of physical properties, in particular in magnetism, as a function of the excess oxygen concentration. Observed experimental results resolved the complexity in the magnetic phase diagram of the previous works. At least three different antiferromagnetic phases separated by the biphasic regions are discovered in the present concentration range. In particular the samples with δ larger than about 0.1 exhibit a new type of magnetic ordering with the in plane cycloid-type incommensurate modulation. (author)

[en] The structures of CD₃ND₃Cl, CD₃ND₃I, CD₃ND₃BF₄, (CD₃ND₃)₂SnCl₆, and CD₃ND₃SnBr₃ crystals were studied with time-of-flight type high-resolution powder diffractometers using spallation pulsed neutron sources. The orientations of the CD₃ND₃ cations, including the positions of the D atoms, were determined at all the room temperature phases and at the low temperature phases of CD₃ND₃I and (CD_3ND₃)₂SnCl₆. The heat capacity experiments were also performed for both protonated and deuterated analogs of these compounds. From both structural and thermodynamic points of view, it was found that the transitions are mainly associated with the order-disorder change of the orientations of the CD₃ND₃ cations. (author)

[en] Variable-energy (0-30keV) positron beam studies have been carried out on 200 keV Se-implanted and 70 keV Si-implanted GaAs specimens before and after annealing for electrical activation. From the measurements of Doppler broadened profiles as a function of incident positron energy, it was found that vacancy clusters with high concentration were introduced in the annealed specimen after Se implantation. From the parallel measurement of electrical characteristics, a higher activation efficiency was found for the higher concentration of vacancy clusters. That fact implies that electrons supplied by the activation of Se also convert the charge state of As vacancies from positive to negative. In contrast, no vacancy clusters were introduced in the Si-implanted GaAs. (author)

[en] A study of the morphology and light-transmissivity in nine commercial samples of high-density polyethylene (HDPE) sheets has been carried out. The sheets were produced by the plastic-film extrusion process in nine Jordanian plastic factories. The variations in the samples were determined in terms of crystallinity, crystallite size, heat of fusion, and melting point. X-ray diffraction, ultra violet and visible absorption spectroscopy, and differential scanning calorimetry (DSC) techniques have been used. The nine samples have relatively high x-ray crystallinity (46.1 - 60.8 %). The crystallite size are relatively large (79 - 103 angstroms). The melting point is in the temperature range 127.4 - 132.6 degrees celsius in the samples which were thermally-treated (annealed), and the heat of fusion is in the range (178.6 - 214.0 J/g) in these samples. Annealing of HDPE sheets in vacuum improved the crystallinity especially at temperatures below the melting point (a crystallinity of 73.2% was obtained at 105 degrees celsius). Samples with higher crystallinity showed better transmissivity of visible light. X-ray diffraction crystallinity reveals the variations in the morphology more sensitively than the DSC method. 38 refs., 16 figs., 12 tabs. (A.M.H.)

[en] The internal conversion electron and Moessbauer isomer shifts of ¹¹⁹Sn and ¹²⁵Te were measured for different metal matrices into which radioactive ¹¹⁹Sb (T_1/2) = 38.1h) and ¹²⁵I (T_1/2 = 60 d) were introduced by means of ion-implantation. The conversion electron spectra were observed with an iron-free air core β-ray spectrometer. From the correlation between the intensity ratios of O-shell to N₁-shell conversion electrons, the changes of nuclear charge radii of the 23.87 keV M1 transitions of ¹¹⁹Sn and of the 35.46 keV M1 transition of ¹²⁵Te were determined. Similarly, the change of nuclear radius of ¹²¹Sb was evaluated from the isomer shift and MO calculation. (author)

[en] The Fifth Users Meeting for the Advanced Photon Source (APS) was held on October 14--15, 1992, at Argonne National Laboratory. Scientists and engineers from universities, industry, and national laboratories came to review the status of the facility and to look ahead to the types of forefront science that will be possible when the APS is completed. The presentations at the meeting included an overview of the project, funding opportunities, advances in synchrotron radiation applications, and technical developments at the APS. In addition, the 15 Collaborative Access Teams that have been approved to date participated in a poster session, and several vendors displayed their wares. The actions taken at the 1992 Business Meeting of the Advanced Photon Source Users Organization are also documented

[en] Papers on nuclear-spectroscopic investigations on hyperfine interactions are presented: theoretical and experimental investigations of hyperfine structure, recommendations on usiing results in nuclear physics, solid-state physics and etc

[en] The technique of solution molecule dynamics investigation by quasielastic slow neutron scattering is described. Liquid solutions of surfactant triton X-100 before and after contact with hydrophobic sorbent of graphitized soot and hydrophilic sorbent of KSK silicagel were investigated by means of the suggested technique. The obtained values of self diffusion coefficient D and contributions in this coefficient from collective and one particle motion of molecules, and resident time in oscillation state to are presented for liquid solutions with different triton X-100 concentrations. The analysis of data obtained is performed. (author). 20 refs., 3 tab., 3 figs