Search results for "PHASE"

showing 10 items of 6344 documents

Ionic liquid crystals based on viologen dimers: tuning the mesomorphism by varying the conformational freedom of the ionic layer

2016

ABSTRACTWe investigated the liquid crystal behaviour of newly synthesised bistriflimide salts of symmetric viologen dimers. A smectic A phase was observed for intermediate spacer lengths and for relatively long lateral alkyl chains. The systems were characterised by thermal analysis, polarised optical microscopy, X-ray scattering and solid-state NMR. An intermediate ordered smectic phase was also exhibited by the compounds (except for systems with very short lateral chains) consisting of molten layers of alkyl chains and partially ordered ionic layers. These results, relating to the mesomorphic behaviour of viologen salts, are qualitatively compared to those of the more common imidazolium s…

4-4?-bipyridinium4-4ʹ-bipyridiniumMaterials scienceIonic liquid crystals; viologens; 4-4ʹ-bipyridiniumIonic bonding02 engineering and technology010402 general chemistry01 natural scienceschemistry.chemical_compoundLiquid crystalPhase (matter)medicineOrganic chemistryGeneral Materials ScienceBistriflimideviologensAlkylSettore CHIM/02 - Chimica Fisicachemistry.chemical_classificationviologenChemistry (all)MesophaseViologenGeneral ChemistrySettore CHIM/06 - Chimica Organica4-4ʹ-bipyridinium; Ionic liquid crystals; viologens; Condensed Matter Physics; Materials Science (all); Chemistry (all)021001 nanoscience & nanotechnologyCondensed Matter Physics0104 chemical sciencesCrystallographychemistryIonic liquidIonic liquid crystalsIonic liquid crystalMaterials Science (all)0210 nano-technologymedicine.drug
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Mossbauer spectroscopic study of the thermal spin crossover in [Fe(II)(isoxazole)(6)](ClO(4))(2)

2008

The (57)Fe Mossbauer spectroscopy of mononuclear [Fe(II)(isoxazole)(6)](ClO(4))(2) has been studied to reveal the thermal spin crossover of Fe(II) between low-spin (S = 0) and high-spin (S = 2) states.Temperature-dependent spin transition curves have been constructed with the least-square fitted data obtained from the Mossbauer spectra measured at various temperatures between 84 and 270 K during a cooling and heating cycle. This compound exhibits an unusual temperature-dependent spin transition behaviour with T(C)(down arrow) = 223 and T(C)(up arrow) = 213 K occurring in the reverse order in comparison to those observed in SQUID observation and many other spin transition compounds. The comp…

5-BIS(PYRIDIN-2-YL)-1Phase transitionMossbauer spectroscopySpin transition2Inorganic compoundsABPT=4-AMINO-3chemistry.chemical_compoundMOLECULESNuclear magnetic resonanceSpin crossoverMössbauer spectroscopyMagnetic propertiesPERCHLORATEGeneral Materials Science4-TRIAZOLEIsoxazoleSpin (physics)Mössbauer effectORDER-DISORDER PHENOMENABIS(3-AMINOPROPYL)(2-PYRIDYLMETHYL)AMINECOMPOUNDGeneral ChemistryAtmospheric temperature rangeCondensed Matter PhysicsSTATECrystallographychemistryPhase transitionsPHASE-TRANSITIONCondensed Matter::Strongly Correlated ElectronsCOMPLEXESLIGANDSABPT=4-AMINO-35-BIS(PYRIDIN-2-YL)-124-TRIAZOLEJournal of Physics and Chemistry of Solids
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Varying chiral ratio of Pinic acid enantiomers above the Amazon rainforest

2023

Chiral chemodiversity plays a crucial role in biochemical processes such as insect and plant communication. However, the vast majority of organic aerosol studies do not distinguish between enantiomeric compounds in the particle phase. Here we report chirally specified measurements of secondary organic aerosol (SOA) at the Amazon Tall Tower Observatory (ATTO) at different altitudes during three measurement campaigns at different seasons. Analysis of filter samples by liquid chromatography coupled to mass spectrometry (LC-MS) has shown that the chiral ratio of pinic acid (C9H14O4) varies with increasing height above the canopy. A similar trend was recently observed for the gas-phase precursor…

540 Chemistry and allied sciencesAtmospheric ScienceChemistryPhase (matter)540 ChemieAnalytical chemistryParticleMoleculeDegradation (geology)ParticulatesEnantiomerMass spectrometryAerosol
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Formation of 3-methyl-1,2,3-butanetricarboxylic acid via gas phase oxidation of pinonic acid – a mass spectrometric study of SOA aging

2012

Abstract. This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS). The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a very low volatile α-pine…

540 Chemistry and allied sciencesAtmospheric ScienceChromatographyChemistryAtmospheric-pressure chemical ionizationFraction (chemistry)Mass spectrometryMass spectrometriclcsh:QC1-999JGas phaseAerosollcsh:ChemistryAcid oxidationlcsh:QD1-999540 ChemieYield (chemistry)ddc:550lcsh:PhysicsAtmospheric Chemistry and Physics
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Influences of Ortho‐Fluoroazobenzenes on Liquid Crystalline Phase Stability and 2D (Planar) Actuation Properties of Liquid Crystalline Elastomers

2019

540 Chemistry and allied sciencesMaterials sciencePolymers and PlasticsLiquid crystallinePhase stabilityOrganic ChemistryCondensed Matter PhysicsElastomerPlanarChemical engineering540 ChemiePolymer chemistryMaterials ChemistryPhysical and Theoretical ChemistryMacromolecular Chemistry and Physics
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Sublimation of icy aggregates in the coma of comet 67P/Churyumov–Gerasimenko detected with the OSIRIS cameras on board Rosetta

2016

Beginning in 2014 March, the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67P/Churyumov¿Gerasimenko using both the wide angle camera (WAC) and the narrow angle camera (NAC). The many observations taken since July of 2014 have been used to study the morphology, location, and temporal variation of the comet's dust jets. We analysed the dust monitoring observations shortly after the southern vernal equinox on 2015 May 30 and 31 with the WAC at the heliocentric distance Rh = 1.53 AU, where it is possible to observe that the jet rotates with the nucleus. We found that the decline of brightness a…

67P/Churyumov-GerasimenkoBrightness010504 meteorology & atmospheric sciences530 PhysicsInfraredCometdata analysis[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]Narrow angleComets: individual: 67P/Churyumov-Gerasimenko; Methods: data analysis; Methods: numerical; Methods: observationalFOS: Physical sciencesEquinoxAstrophysics01 natural sciencesAstronomi astrofysik och kosmologiMethods: observationalMethods: data analysisindividual: 67P/Churyumov-Gerasimenko [Comets]0103 physical sciencesAstronomy Astrophysics and Cosmologyobservational [Methods]cometsdata analysis [Methods]010303 astronomy & astrophysics0105 earth and related environmental sciencesobservational method: numerical methodPhysicsEarth and Planetary Astrophysics (astro-ph.EP)Comets: individual: 67P/Churyumov-Gerasimenkomethods: data analysis methods: numerical methods: observational comets: individual: 67P/Churyumov–Gerasimenkonumerical [Methods]biology[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]Methods: numerical520 AstronomyAstronomyAstronomy and Astrophysics620 Engineeringbiology.organism_classificationOn boardSpace and Planetary Science[SDU]Sciences of the Universe [physics]Sublimation (phase transition)QB651OsirisAstrophysics - Earth and Planetary Astrophysics
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A Phase I/II Dose-Escalation Multi-Center Study to Evaluate the Safety of Infusion of Natural Killer Cells or Memory T Cells As Adoptive Therapy in C…

2021

Abstract Background: Adoptive cell immunotherapies for opportunistic virus in immunocompromised patients using haploidentical memory T cells have shown to be safe and effective. Since severe cases of COVID-19 present a dysregulated immune system with T cell lymphopenia and a hyper-inflammatory state we have proposed that a similar strategy could be proven to be efficient for COVID-19 patients. This is a study protocol of an open-label, multicenter, double-arm, randomized, dose-finding phase I/II clinical trial to evaluate the feasibility, safety, tolerability, and efficacy of the administration of a single dose of allogenic SARS-CoV-2 specific memory CD45RA - T cells and Natural Killer (NK)…

704.Cellular Immunotherapies: Clinicalbusiness.industryImmunologyCell BiologyHematologymedicine.disease_causemedicine.diseaseBiochemistryPneumoniaPhase i iiMulti center studyImmunologymedicineDose escalationbusinessCoronavirusBlood
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Thermomineral waters of Greece: geochemical characterization

2020

75 °C). In terms of pH most results vary from 5.5 to 823 °C) ii) warm (23 40 °C) iii) thermal (40 75 °C) and iv) hyperthermal (&gtfew springs show either very low pH (&lt10) proposing serpentinization processes. Regarding TDS concentrations collected waters can be subdivided into low salinity (up to 1.5 g/L) brackish (up to 20 g/L) and saline (up to 43 g/L). The medium high salinities can be justified by mixing with sea water and/or strong waterrock interaction processes. Isotope composition of O and H ranges from 12.7 to +2.7 ‰ SMOW and from 91 to +12 ‰ SMOW respectively and is generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Only few water samples show a positive shift for δ18O possibly related to high temperature waterrock interaction processes. Carbon dioxide (18 997000 μmol/mol) or N2 (1100 989000 μmol/mol) or CH4 (&ltMany geothermal areas of Greece are located in regions affected by Miocene or Quaternary volcanism and in continental basins characterised by elevated heat flow. Moreover the majority of them is found along the coast as well as in islands of the Aegean Sea and thus thermal water is often brackish to saline due to marine intrusion into costal aquifer. In the present study almost 300 thermal and cold mineral water samples were collected along the Hellenic territory with their physicochemical parameters (temperature pH electrical conductivity and Eh) and the amount of bicarbonates (titration with 0.1N HCl) being determined in situ. Additionally gases found either in free or dissolved phase were sampled. Both water and gas samples were analysed at the INGVPa laboratories for major ions (Ion Chromatography) silica (Inductively Coupled Plasma Optical Emission Spectrometry) chemical composition of free and dissolved gases (Gas Chromatography) water isotopes (O and H) and carbon and helium isotopes of free and dissolved gases (Mass Spectrometry). The temperature of the investigated waters ranges from 6.5 to 98°C pH from 1.96 to 11.98 whilst Total Dissolved Solids (TDS) from 0.06 to 43 g/L. Based on the temperature parameter waters can be divided into four groups: i) cold (&lt0.5 913000 μmol/mol) are the prevailing gas species found in the studied sites. The δ13CCO2 values ranged from 20.1 to +8.5 ‰ whilst the isotope ratio of He from 0.21 to 6.71 R/RA.4) suggesting interaction with H2Srich gases or very high pH values (&gtSettore GEO/08 - Geochimica E Vulcanologia
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Description of hard-sphere crystals and crystal-fluid interfaces: a comparison between density functional approaches and a phase-field crystal model.

2012

In materials science the phase field crystal approach has become popular to model crystallization processes. Phase field crystal models are in essence Landau-Ginzburg-type models, which should be derivable from the underlying microscopic description of the system in question. We present a study on classical density functional theory in three stages of approximation leading to a specific phase field crystal model, and we discuss the limits of applicability of the models that result from these approximations. As a test system we have chosen the three--dimensional suspension of monodisperse hard spheres. The levels of density functional theory that we discuss are fundamental measure theory, a …

: Physics [G04] [Physical chemical mathematical & earth Sciences]FOS: Physical sciencesHard spheresCondensed Matter - Soft Condensed Matterlaw.inventionCrystal: Physique [G04] [Physique chimie mathématiques & sciences de la terre]lawPhase (matter)Crystal modelVacancy defectSoft Condensed Matter (cond-mat.soft)Density functional theoryStatistical physicsCrystallizationFree parameterMathematicsPhysical review. E, Statistical, nonlinear, and soft matter physics
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DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF 0.8Na0.5 Bi0.5 TiO3-0.2BaTiO3 MODIFIED WITH SODIUM NIOBATE

2022

This work was supported by the Research Council of Lithuania (Project S-LLT-20-4). This work has been supported by Mutual Funds Taiwan–Latvia– Lithuania Cooperation Project Application LV-LT-TW/2020/10.

:NATURAL SCIENCES [Research Subject Categories]perovskitesGeneral Physics and Astronomydielectric spectroscopyphase transitions
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