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1.
The early planning for the International Space Year (ISY) is outlined. Public and educational ISY activities under way in the US by 1990 are described. They include films and TV programs, public exhibitions, books and periodicals, public events, conferences and symposia, and school programs and materials 相似文献
2.
A. Bianconi Y. Busby M. Fratini V. Palmisano L. Simonelli M. Filippi S. Sanna F. Congiu A. Saccone M. Giovannini S. De Negri 《Journal of Superconductivity and Novel Magnetism》2007,20(7-8):495-501
Here we report synthesis and characterization of high quality samples of the superconducting system Mg1−x
Al
x
B2, with a novel optimized preparation method, in a wide range of Al concentration. All the physical properties of the samples
can be tuned continuously with increasing Al content. We have characterized the samples for their structural, morphological
and magnetic properties with high resolution XRD, SEM-EDS and susceptibility measurements. We have prepared a large number
of Al doped MgB2 in the range 0<x<0.57. All the samples are bulk superconductors and the critical temperature show a smooth and regular behavior as a function
of x.
This work was supported by European project 517039 “Controlling Mesoscopic Phase Separation” (COMEPHS) (2005).
An erratum to this article can be found at 相似文献
3.
M. Fratini G. Campi L. Simonelli V. Palmisano S. Agrestini M. Filippi N. L. Saini A. Bianconi 《Journal of Superconductivity and Novel Magnetism》2005,18(5-6):671-674
The interstitial oxygen ordering in a La2CuO4+ y (y = 0.08) single crystal with a T c = 38 K has been investigated. We have studied the growth dynamics of the three dimensional (3D) ordered phase, called Q2, at different temperatures under X-ray illumination. The critical temperature T 0~334 K of the order-disorder transition for the Q2 phase has been determined. We have found that the illumination of the sample with a continuous polarized synchrotron radiation X-ray flux stimulates the oxygen ordering kinetics. The photoinduced ordering process shows a threshold characteristic of cooperative phenomena and its kinetics shows a temperature dependence that is controlled by the activation energy E A = 100 meV. 相似文献
4.
V. Palmisano S. Agrestini G. Campi M. Filippi L. Simonelli M. Fratini A. Bianconi S. De Negri M. Giovannini A. Saccone A. N. Fitch M. Brunelli I. Margiolaki 《Journal of Superconductivity and Novel Magnetism》2005,18(5-6):737-741
The thermal lattice expansion in the superconducting Mg1? x Al x B2 system (x = 0, 0.13, and 0.59) has been measured using high-resolution X-ray powder diffraction. An unusual large negative thermal expansion (NTE) appears for temperatures below T * = 60 K in the MgB2. The NTE effect increases in Mg0.87Al0.13B2 and disappears at high Al content in the Mg0.59Al0.41B2 where the temperature dependence of volume follows a standard Einstein model in the whole temperature range. The anomalous behavior of the thermal expansion provides a direct evidence in the physics of diborides for the relevance of the proximity to the 2.5 Lifshitz electronic topological transition where the Fermi surface of the σband changes from a two-dimensional (2D) to a three-dimensional (3D) topology. 相似文献
5.
The European “Floods Directive” 2007/60/EC (FD) asks Member States to develop flood risk maps on the bases of most appropriate and advanced tools, with particular attention on limiting required economic efforts. The question arises on how these tools should be selected so as to supply all the knowledge that is required to develop Flood Risk Management Plans (FRMPs). By analysing the implementation of the FD in the Po River Basin (Italy), the paper describes and compares two different approaches for flood risk assessment: the expert driven-qualitative approach vs. the quantitative approach based on damage models. The comparison shows, as expected, that quantitative approaches supply more useful knowledge for the development of FRMPs (and for flood risk management in general) with respect to qualitative approaches. However, they still present limits which prevent their adoption without critically consider the peculiarities of the investigated area in terms of available knowledge on hazard, exposure and vulnerability. Accordingly, considerations are supplied on how effectiveness of quantitative approaches can be maximized, towards flood risk management objectives. 相似文献
6.
Ana Fakin Crystel Bonnet Anne Kurtenbach Saddek Mohand-Said Ditta Zobor Katarina Stingl Francesco Testa Francesca Simonelli Jos-Alain Sahel Isabelle Audo Eberhart Zrenner Marko Hawlina Christine Petit 《International journal of molecular sciences》2021,22(19)
In contrast to USH2A, variants in ADGRV1 are a minor cause of Usher syndrome type 2, and the associated phenotype is less known. The purpose of the study was to characterize the retinal phenotype of 18 ADGRV1 patients (9 male, 9 female; median age 52 years) and compare it with that of 204 USH2A patients (111 male, 93 female; median age 43 years) in terms of nyctalopia onset, best corrected visual acuity (BCVA), fundus autofluorescence (FAF), and optical coherence tomography (OCT) features. There was no statistical difference in the median age at onset (30 and 18 years; Mann–Whitney U test, p = 0.13); the mean age when 50% of the patients reached legal blindness (≥1.0 log MAR) based on visual acuity (64 years for both groups; log-rank, p = 0.3); the risk of developing advanced retinal degeneration (patch or atrophy) with age (multiple logistic regression, p = 0.8); or the frequency of cystoid macular edema (31% vs. 26%, Fisher’s exact test, p = 0.4). ADGRV1 and USH2A retinopathy were indistinguishable in all major functional and structural characteristics, suggesting that the loss of function of the corresponding proteins produces similar effects in the retina. The results are important for counseling ADGRV1 patients, who represent the minor patient subgroup. 相似文献
7.
8.
Merrick L. Shively Gary Lavigne Anthony P. Simonelli 《Drug development and industrial pharmacy》1991,17(18):2511-2519
The diffuse reflectance of infra-red energy from microcapsules was shown to be a useful analytical technique to study the structural properties of microcapsules. The technique of diffuse reflectance is unique in that the anisotropic nature of reflected light enables spectral differences to be explained on the basis of molecular orientation. As a result of the collection and analysis of diffuse spectra, spectral differences that may correspond to structural differences in the capsule wall structure were found to be dependent on the core material. More specifically, in microcapsules of kaolin and talc, produced with a block copolymer of d-tartaric acid and 1,8-octanediol, the relative orientation of hydroxyl functional groups for the respective core materials differed by forty-nine degrees while carbonyl groups differed by 15 degrees. 相似文献
9.
Rafiq R. A. Abou-Shaaban Joseph L. Haberfeld Edward M. Barrall Julian F. Johnson Anthony P. Simonelli 《Polymer Engineering and Science》1976,16(8):544-551
The techniques of thermogravimetric and derivative thermogravimetric analyses have been applied to the determination of temperatures and heats of decompositions of four ethylene/propylene rubbers and seven cross-linked polyethylenes in nitrogen. These materials are commonly used in the wire and ruble industry as dielectric insulation. The polymers were found to decompose in at least three overlapping stages. Each stage has an activation energy characteristic of the process. Differential thermal analysis was significantly less useful in this study due to the conflict of the endothermal heat of vaporization and the exothermal heat of decomposition. 相似文献
10.