Search results for "dron"
showing 10 items of 4363 documents
Crystal and molecular structure of tris(mepirizole) copper(II) hexafluorophosphate [mepirizole = 4-methoxy-2-5-methoxy-3-methyl-1h-pyrazol-1-yl)-6-me…
1992
Abstract The X-ray crystal structure of Cu(mep)3(PF6)2 [mep = mepirizole or 4-methoxy-2-(5-methoxy-3-methyl-1H-pyrazol-1-yl)-6 methylpyrimidine], obtained from stoichiometric quantities of mep, Cu(NO3)2 and KPF6 in water/ethanol solution was determined. The trisbidentate Cu(mep)32+ cation is observed for the first time. One of the three mep molecules is disordered over two sets of positions related by crystallographic symmetry. The mep molecules exhibit two different conformations A and B: conformation B, which is observed for the first time, derives from the usual conformation A by rotating the pyrimidine ring by 180° around the central CN bond and rotating by 180° the methoxy group bonde…
Structural, magnetic, and spectroscopic comparative studies on four new derivatives of DIMMAL (2-di1H-2-imidazolylmethylmalonate): a novel generator …
2005
This paper reports the synthesis, structure solution, and magnetic characterization of four new DIMMAL-containing compounds (H 2 DIMMAL = 2-di1H-2-imidazolylmethylmalonic acid), H 2 DIMMAL.H 2 O (1), Na 2 (DIMMAL).5H 2 O (2), [Cu(HDIMMAL) 2 ] (3), and [Cu 2 (DIMMAL) 2 (H 2 O) 2 ].2H 2 O (4). Compound 1, containing two carboxylates and two protonated imidazole rings, adopts the dizwitterion configuration. These monohydrate MBBs pack together into a 3D array driven, as in the other three cases herein reported, by a combination of multiple-path H-bonds and aromatic-aromatic interactions. Compound 2 consists of centrosymmetric Na + tetramers in which four NaO 6 distorted octahedra are interconn…
Cobalt(II) Sheet-Like Systems Based on Diacetic Ligands: from Subtle Structural Variances to Different Magnetic Behaviors
2009
The preparation, X-ray crystallography, and magnetic investigation of the compounds [Co(H(2)O)(2)(phda)](n) (1), [Co(phda)](n) (2), and [Co(chda)](n) (3) [H(2)phda = 1,4-phenylenediacetic acid and H(2)chda = 1,1-cyclohexanediacetic acid] are described herein. The cobalt atoms in this series are six- (1) and four-coordinated (2 and 3) in distorted octahedral (CoO(6)) and tetrahedral (CoO(4)) environments. The structures of 1-3 consists of rectangular-grids which are built up by sheets of cobalt atoms linked through anti-syn carboxylate bridges, giving rise to either a three-dimensional structure across the phenyl ring (1 and 2) or to regularly stacked layers with the cyclohexyl groups acting…
Synthesis of a labile sulfur-centred ligand, [S(H)C(PPh2S)2]−: structural diversity in lithium(i), zinc(ii) and nickel(ii) complexes
2016
A high-yield synthesis of [Li{S(H)C(PPh2S)2}]2 [Li2·(3)2] was developed and this reagent was used in metathesis with ZnCl2 and NiCl2 to produce homoleptic complexes 4 and 5b in 85 and 93% yields, respectively. The solid-state structure of the octahedral complex [Zn{S(H)C(PPh2S)2}2] (4) reveals notable inequivalence between the Zn-S(C) and Zn-S(P) contacts (2.274(1) Å vs. 2.842(1) and 2.884(1) Å, respectively). Two structural isomers of the homoleptic complex [Ni{S(H)C(PPh2S)2}2] were isolated after prolonged crystallization processes. The octahedral green Ni(ii) isomer 5a exhibits the two monoprotonated ligands bonded in a tridentate (S,S',S'') mode to the Ni(ii) centre with three distinctl…
Synthesis, spectroscopic characterization and in vitro antimicrobial activity of diorganotin(IV) dichloride adducts with [1,2,4]triazolo-[1,5-a]pyrim…
2006
Abstract The heterocyclic ligands [1,2,4]triazolo-[1,5-a]pyrimidine (tp) and 5,7-dimethyl-[1,2,4]triazolo-[1,5-a]pyrimidine (dmtp), react with diorganotin dichlorides giving the addition compounds Me2SnCl2(tp)2, Et2SnCl2(tp)2, Me2SnCl2(dmtp)2, Et2SnCl2(dmtp)2, Bu2SnCl2(dmtp), Ph2SnCl2(dmtp). The organotin:ligand stoichiometry goes from 1:2 to 1:1 by increasing the steric hindrance of the organic groups bound to tin. The compounds have been characterized by means of infrared, 119Sn Mossbauer and 1H AND 13C NMR spectroscopy. The ligands presumably coordinate to tin classically through the nitrogen atom at the position 3. The 1:1 complexes adopt trigonal bipyramidal structures, with the organi…
FIRST MEASUREMENT OF THE STRANGE QUARK ASYMMETRY AT THE Z(0) PEAK
1995
A measurement of the strange quark forward-backward asymmetry at the Z0 peak was performed using 718,000 multihadronic Z0 decays collected by the DELPHI detector at LEP in 1992. The s-quark was tagged by the presence of high momentum charged kaons identified by the Ring Imaging Cherenkov detector and by Λ0;s decaying into pπ-. The s-quark purity obtained was estimated for the two hadrons to be 43%. The average s-quark asymmetry was found to be 0.131±0.035 (stat.) ±0.013 (syst.). The forward-backward asymmetry was measured for unresolved d-and s-quarks, tagged by the detection of a high energy neutron or neutral kaon in the Hadron Calorimeter. The combined d-and s-quark purity was 69% and th…
Mini-drones swarms and their potential in conflict situations
2021
Drones are currently used for a wide range of operations, such as border surveillance, general surveillance, reconnaissance, transport, aerial photography, traffic control, earth observation, communications, broadcasting, and armed attacks. This paper examines the swarming and associated abilities to overwhelm a combatant as well as bring extra functionality by means of extra sensors spread throughout the swarm. The strategy of stealth is becoming increasingly less effective. Combatants can not only sense them, but can also successfully destroy them (although this cannot be said for nano-drones). For mini-drones, objectives can be enhanced by the strategy of overwhelming. peerReviewed
APPLICATION OF UNMANNED AERIAL VEHICLES FOR GLACIER RESEARCH IN THE ARCTIC AND ANTARCTIC
2019
Unmanned aerial vehicles or drones are nowadays widely used in a broad field of scientific and commercial applications. Despite this, it is quite a new method for glacier mapping in polar regions and has a lot of advantages, as well as disadvantages over more classical remote sensing instruments. Here we examine the main issues associated with the application of drones for glacier research from our experience in Iceland, Greenland and the Antarctic. We use DJI Phantom series drones for the obtaining of aerial photographs and produce digital surface models (resolution of 8 – 16 cm) and orthomosaics (resolution of 2 – 4 cm) for glacier mapping. Several issues related to the ground control poi…
Advanced Beam Dynamics Design for the Superconducting Heavy Ion Accelerator HELIAC
2019
The 10th International Particle Accelerator Conference, IPAC2019, Melbourne, Australia, 19 May 2019 - 24 May 2019; JACoW Publishing, Geneva, Switzerland 928-931 (2019). doi:10.18429/JACOW-IPAC2019-MOPTS034
Structure and superconductivity in LnNi2B2C: comparison of calculation and experiment
2001
Abstract The experimental relation between the superconducting transition temperature ( T c ) and lattice size for the lanthanide nickel borocarbides is clarified. The electronic density of states (DOS) at the Fermi energy is calculated by the LMTO method for selected non-magnetic lanthanides. The T c and the DOS are both shown to scale in the same way with a structural parameter that characterizes the bond angle in the NiB 4 tetrahedra. The results strongly support arguments that the suppression of superconductivity on going from smaller to larger lanthanides in the quaternary nickel borocarbides is structurally driven. A structure– T c relationship of this type is unusual for intermetalli…