Neutron Diffraction Characterization of Permanent Magnet Phases

1999 ◽  
Vol 577 ◽  
Author(s):  
William B. Yelon
Keyword(s):  
Neutron Diffraction ◽  
High Performance ◽  
Permanent Magnets ◽  
Structural Data ◽  
Structure Property ◽  
Magnetic Phases ◽  
Property Relations ◽  
Large Numbers ◽  
New Compounds

ABSTRACTNeutron diffraction has been invaluable in the characterization of intermetallic magnetic phases due to the unique properties of the neutron and the availability of high performance powder diffractometers that allow large numbers of samples to be investigated. The structural data derived from these studies serves as fundamental input for theory, and constraints on analyses of data from other methods, such as Mossbauer spectroscopy. The empirical structure-property relations derived from these studies serves to guide synthesis of new compounds and may help to define the next generation of high performance permanent magnets.

scholarly journals Multiblock Copolymers of Norbornene and Cyclododecene: Chain Structure and Properties

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1756
Author(s):  
Yulia I. Denisova ◽  
Georgiy A. Shandryuk ◽  
Marianna P. Arinina ◽  
Ivan S. Levin ◽  
Vsevolod A. Zhigarev ◽  
...  
Keyword(s):  
First Generation ◽  
Average Length ◽  
Chain Structure ◽  
Random Copolymers ◽  
Multiblock Copolymers ◽  
Structure Property ◽  
Reaction Conditions ◽  
Property Relations ◽  
Cross Metathesis

We investigate the structure–property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting. We demonstrate that isolated dodecenylene units can be incorporated into crystalline lamellas so that even nearly random copolymers should retain crystallinity. Weak high-temperature endotherms observed in the multiblock copolymers of norbornene with cyclododecene and other cycloolefins could indicate that the corresponding systems are microphase-separated in the melt state.

scholarly journals Isolation and Characterization of New Anti-Inflammatory and Antioxidant Components from Deep Marine-Derived Fungus Myrothecium sp. Bzo-l062

Marine Drugs ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. 597
Author(s):  
Xiaojie Lu ◽  
Junjie He ◽  
Yanhua Wu ◽  
Na Du ◽  
Xiaofan Li ◽  
...  
Keyword(s):  
Deep Sea ◽  
High Performance ◽  
Oxygen Radical ◽  
Normal Phase ◽  
Oxide Formation ◽  
Nitric Oxide Formation ◽  
Isolation And Characterization ◽  
Anti Inflammatory ◽  
New Compounds

In the present study, four new compounds including a pair of 2-benzoyl tetrahydrofuran enantiomers, namely, (−)-1S-myrothecol (1a) and (+)-1R-myrothecol (1b), a methoxy-myrothecol racemate (2), and an azaphilone derivative, myrothin (3), were isolated along with four known compounds (4–7) from cultures of the deep-sea fungus Myrothecium sp. BZO-L062. Enantiomeric compounds 1a and 1b were separated through normal-phase chiral high-performance liquid chromatography. The absolute configurations of 1a, 1b, and 3 were assigned by ECD spectra. Among them, the new compound 1a and its enantiomer 1b exhibited anti-inflammatory activity, inhibited nitric oxide formation in lipopolysaccharide-treated RAW264.7 cells, and exhibited antioxidant activity in the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and oxygen radical absorbance capacity assays.

Chemical Design and Structural Chemistry of Lwir Optical Materials

1990 ◽  
Vol 216 ◽  
Author(s):  
C.K. Lowe-Ma ◽  
D.O. Kipp ◽  
T.A. Vanderah
Keyword(s):  
Crystal Structure ◽  
Electronic Configuration ◽  
Structure Type ◽  
Optical Transparency ◽  
Structure Property ◽  
Long Wavelength ◽  
Structure Property Relationships ◽  
New Compounds ◽  
Long Wavelength Infrared

ABSTRACTSome applications for long-wavelength infrared (LWIR) windows require environmental durability and mechanical strength in addition to infrared optical transparency; i.e., the windows must simultaneously serve as optical and as structural ceramics. The requirement of optical transparency at long IR wavelengths eliminates from consideration all ceramics based on oxides and other light-anion compounds, making this a particularly difficult materials problem. The structure-property relationships and chemical rationale used to guide both the screening of known compounds and the synthesis of new compounds likely to possess the desired properties rely on factors such as atomic mass, electronic configuration, coordination number, and crystal structure type.Our research has included the directed synthesis and characterization of a number of ternary indium sulfides as well as ternary calcium yttrium sulfides. Ternary indium sulfides feature both tetrahedral and octahedral coordination of indium. The crystal structure of KInS2 and its relationship to structures observed in other systems such as AIn2S4, A = Ca,Sr,Ba, is described. The crystal structure of CaY2S4 along with studies of yttrium-doped CaS are also described. The AIn2S4 compounds are more fully described in references [1] and [2].

Crystal Chemistry, Synthesis, and Characterization of Infrared Optical Materials

1989 ◽  
Vol 152 ◽  
Author(s):  
D. O. Kipp ◽  
C. K. Lowe-Ma ◽  
T. A. Vanderah
Keyword(s):  
Inorganic Compounds ◽  
Solid State Chemistry ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Structure Property Relationships ◽  
Ternary Sulfide ◽  
Directed Synthesis ◽  
New Compounds ◽  
Polycrystalline Form

ABSTRACTNon-oxide inorganic compounds such as sulfides, phosphides, and mixed-anion sulfidephosphides are of interest as possible infrared window materials. Our research on the solid state chemistry and structure-property relationships of these materials includes the directed synthesis of new compounds as well as the study of compounds that have been reported in the literature but which have been incompletely characterized for this application. The present work includes investigations of three ternary sulfide systems: ZnGa2S4, AIn2S4, (A = Ca,Sr,Ba), and CaY2S4. Samples were prepared in polycrystalline form and/or as crystals. New compounds were obtained in our studies of the CaIn2S4, SrIn2S4, and CaY2S4 systems. Compounds were characterized by X-ray diffraction, elemental analysis, FMR, and thermogravimetric analysis.

scholarly journals Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

2013 ◽  
Vol 9 ◽  
pp. 866-876 ◽  
Author(s):  
Amaresh Mishra ◽  
Elena Mena-Osteritz ◽  
Peter Bäuerle
Keyword(s):  
Density Functional ◽  
Dendritic Structure ◽  
Spectroscopic Properties ◽  
Coupling Reactions ◽  
Structure Property ◽  
Cross Coupling Reactions ◽  
Structure Property Relationships ◽  
Maldi Tof Mass Spectra ◽  
New Compounds

Pd-catalyzed Sonogashira cross-coupling reactions were used to synthesize novel π-conjugated oligothienylene-ethynylene dendrons and their corresponding terpyridine-based ligands. Their complexation with Ru(II) led to interesting novel metallodendrimers with rich spectroscopic properties. All new compounds were fully characterized by 1H and 13C NMR, as well as MALDI–TOF mass spectra. Density functional theory (DFT) calculations performed on these complexes gave more insight into the molecular orbital distributions. Photophysical and electrochemical studies were carried out in order to elucidate structure–property relationships and the effect of the dendritic structure on the metal complexes. Photophysical studies of the complexes revealed broad absorption spectra covering from 250 to 600 nm and high molar extinction coefficients. The MLCT emission of these complexes were significantly red-shifted (up to 115 nm) compared to the parent [Ru(tpy)2]2+ complex.

Characterization of Structure-Property Relations and Second Harmonic Generation of 6-Methoxy-2-Naphthaldehyde

2021 ◽  
pp. 1-13
Author(s):  
D. Rajaniverma ◽  
D. Jagadeeswara Rao ◽  
P. V. Prasanna Kumar ◽  
V. Seetaramaiah ◽  
Y. Ramakrishna
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Structure Property ◽  
Property Relations

scholarly journals Second Zagreb and Sigma Indices of Semi and Total Transformations of Graphs

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zhen Yang ◽  
Micheal Arockiaraj ◽  
Savari Prabhu ◽  
M. Arulperumjothi ◽  
Jia-Bao Liu
Keyword(s):  
Physicochemical Properties ◽  
Molecular Graph ◽  
Vital Role ◽  
Topological Indices ◽  
The Novel ◽  
Structure Property ◽  
Bond Type ◽  
Property Relations

The study of structure-property relations including the transformations of molecules is of utmost importance in correlations with corresponding physicochemical properties. The graph topological indices have been used effectively for such study and, in particular, bond-based indices play a vital role. The bond-additive topological indices of a molecular graph are defined as a sum of edge measures over all edges in which edge measures can be computed based on degrees, closeness, peripherality, and irregularity. In this study, we provide the mathematical characterization of the transformation of a structure that can be accomplished by the novel edge adjacency and incidence relations. We derive the exact expressions of bond type indices such as second Zagreb, sigma indices, and their coindices of total transformation and two types of semitransformations of the molecules which in turn can be used to characterize the topochemical and topostructural properties.

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