1,720,964 research outputs found
Magnetostatic shielding design for electronic apparatus in fusion experiments
No full textIn controlled nuclear fusion research with magnetic confinement, experimental devices must produce high electromagnetic fields that can reach some tesla in the plasma zone. Therefore, a high stray magnetic field, slowly varying as a function of time, is present around the machines. For this reason, the numerous electronic apparatus and plasma diagnostics need an effective magnetostatic shield for their correct working condition.
Many examples of magnetic shields for different apparatus have been analysed: video, various electronic instruments and plasma diagnostics. After a brief description of electromagnetic problems arising in the fusion plants, the paper provides two examples of applications: the shield for a standard rack instrument and the shield for a small photo-multiplier head. The shielding effect has been evaluated considering non-linear materials for the shields. Moreover the magnetic field distortion in the space, due to the presence of the ferromagnetic material, has been evaluated in order to estimate the effect of the shields on the plasma magnetic confinement
'Batterie primarie (non ricaricabili) e secondarie (ricaricabili) a base di elettroliti polimerici basati su ioni magnesio', brevetto italiano depositato il 29-07-1999
No full textFIELD: primary and secondary batteries using magnesium-containing anode.
SUBSTANCE: proposed battery has at least one anode, at least one cathode, at least one electrolyte, and current collectors; at least anode of mentioned batteries is magnesium based and optionally cathode and electrolyte may also contain magnesium. These batteries provide for obtaining separate components and for introducing thin layer of magnesium base electrolyte between anode and cathode.
EFFECT: enhanced performance characteristics, reduced cost
'Magnesium-based primary (non-rechargeable) and secondary (rechargeable) batteries', brevetto europeo depositato il 27-07-2000
No full textThe batteries described herein are of the type comprising at least one anode, at least one cathode and at least one electrolyte, and current collectors, in which at least the anode is magnesium-based, and optionally also the cathode and the electrolyte contain magnesium. Assembly of the batteries involves the preparation of the individual components and the interposition of a thin layer of electrolyte between the magnesium-based anode and the cathode
Zeolitic inorganic-organic polymer electrolytes: synthesis,characterization and ionic conductivity of a material basedon oligo(ethylene glycol) 600, (CH3)2SnCl2 and K4Fe(CN)6
No full textThis paper reports the synthesis of a new Z-IOPE material based on poly(ethylene glycol) 600, (CH3)2SnCl2 and K4Fe(CN)6. This material was synthesized via a sol-gel transition. FIR and MIR spectroscopy studies together with detailed compositional data allowed us to propose a final structure for this Z-IOPE material. It was concluded that this compound is a mixed inorganic-organic network in which clusters formed by tin and iron complexes are bonded together by PEG 600 bridges. The conformation of polyethereal chains in the bulk material is of the TGT (T = trans, G = gauche) type. impedance spectroscopy measurements revealed that the material has a conductivity of 4.77.10-5 S/cm at 21.3 °
Conductivity, thermal stability and morphology of a new Z-IOPE inorganic-organic network with the formula [FexSny(CH3)2y(CN)zClv(CH2nH4n+2On+1)Kl]
No full textThis paper reports accurate studies on the morphology, thermal stability and electrical spectroscopy of a zeolitic inorganic-organic polymer electrolyte (Z-IOPE) with the formula [FexSny(CH3)2y(CN)zCly(C2nH4n+2On+1)Kl]. This material was prepared by means of a sol-gel process. A possible mechanism of the sol-gel process is proposed. Scanning electron microscopy showed that the Z-IOPE resembles a gummy paste with a rough texture and grains on the surface of the bulk material. Thermogravimetric investigations indicated that the material is thermally stable up to approximately 200°C. A detailed study of the mechanism of ion conduction in this system was carried out using impedance spectroscopy in the 20 Hz to 1 MHz range. The analysis of real and imaginary components of conductivity spectra indicated that a full characterization of the AC electrical response for this Z-IOPE system requires an equivalent circuit analysis for frequencies lower than 10 kHz and correlated ionic motion analysis based on the Universal Power Law for frequencies higher than 10 kHz. These studies demonstrated that the Z-IOPE material conducts ionically by a mechanism mainly regulated by segmental motion of the host material, and that charge migration by ion hopping between equivalent coordination sites is not to be completely excluded in the host network. Finally, the conductivity of 4.77 x 10-5 S/cm at 25°
Vibrational studies of the ion-polymer interactions in alpha-hydro-omega-oligo(oxyethylene) hydroxy-poly[oligo(oxyethylene)oxydimethylsililene]/delta-MgCl2
No full textPolymer-polymer and salt-polymer interactions of seven electrolytic complexes based on alpha-liydi-omega-oligo(oxyethylene)h hydroxy-poly[oligo(oxyethlene)oxydimethylsililene] and delta-MgCl2 were studied. This aim was pursued by means of an accurate medium and far FT-IR spectroscopic analysis. By using the decomposition and difference spectroscopy techniques, intensity and frequency of terminal OH and CO stretchings were evaluated in order to detect the presence of anion clusters build up by the coordination or Cl- with -OH groups. The number of chlorine anions per chain coordinated magnesium was established. This analysis allowed us to gain a complete structural picture for these materials, pointing out three possible coordinations of magnesium by polyethereal chains
The first lithium zeolitic inorganic-organic polymer electrolyte based on PEG600, Li2PdCl4 and Li3Fe(CN)6:part I, synthesis and vibrational studies
No full textThe synthesis of Li2PdCl4 and Li3Fe(CN)6 precursors, and the preparation of the first lithium Z-IOPE material obtained by reacting these precursors with poly(ethylene glycol)600 (PEG600) is reported. This new material has been obtained through a sol⇒gel and gel⇒plastic transition. FIR and MIR spectroscopy studies, Raman laser and UV–vis investigations and detailed compositional data allowed us to propose a structural hypothesis and to detect the interactions between ions and the coordinating segments of the host network. It has been concluded that: (1) this compound is a mixed inorganic–organic network in which clusters formed by palladium and iron complexes are bonded together by PEG bridges; (2) the conformation of polyether chains in the bulk material is of the TGT (T=trans, G=gauche) type. The conductivity of the proposed [FexPdy(CN)zClv(C2nH4n+2On+1)Lil] is ≈5.3×10−5 S cm−1 at 35.1 °C
Mechanism of ionic conductivity in poly(ethyleneglycol 400)/(LiCl)x electrolytic complexes: Studies based on Electrical Spectroscopy
No full textThis report describes the preparation of nine solvent-free (PEG400)/(LiCl)x complexes (0.00207 less than or equal to x less than or equal to 1.40665), together with a detailed investigation of their mechanisms of ion motion, carried out by impedance spectroscopy in the range from 20 Hz to 1 MHz. An accurate analysis of the real and imaginary components of their conductivities indicated that a full characterization of the AC electrical response for (PEG400)/(LiCl)x complexes requires an equivalent circuit analysis for frequencies lower than 1 kHz and a correlated ionic motion analysis based on a universal bower law (UPL) for frequencies higher than 1 kHz. Ion-ion interactions in the (PEG400)/ (LiCl)x systems were investigated by studying the equivalent conductivity profiles of the materials as a function of salt concentration and temperature. Results revealed the presence of two conductivity regions in (PEG400)/ (LiCl)x materials, i.e., region I, detected at 0.0720 less than or equal to c1/2 less than or equal to 0.6214 (mol/kg)1/2, and region II, at c1/2 greater than or equal to 0.6214 (mol/kg)1/2. The conductivity mechanisms proposed in these two regions are regulated by two phenomena: intrachain hopping (intra-CH) of ions between coordination sites distributed along the polyethereal chains and interchain hopping (inter-CH) migration of ions. These events were demonstrated to depend on the segmental motion, the distribution of "free" Cl- ions along the PEG chains, and the site relaxation rate. This latter process takes place when a Lif ion hops "successfully" between two distinct polyethereal coordination sites. Finally, these materials show a conductivity of ca. 3.7 x 10-5 S/cm at 25°C
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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