Recent Advances In Air Pollution Analysis

Harrison, Roy M.; Stevens, Robert K.

doi:10.1080/10408348408542775

Cited by 7 publications

(6 citation statements)

References 298 publications

(249 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mechanical treatment of the VHP precursor impairs a specific real structure that enhances the catalytic properties of the final catalyst. 8 The improved catalyst performance is controversially attributed to: (i) an enhanced exposure of the basal planes; 9,10 or (ii) an increase in surface area and the generation of fresh and reactive surfaces, [11][12][13] : or (iii) a decreased particle size and an increased microstrain in the VHP precursor. 8 The modified VHP is transferred to the VPP catalyst in a topotactic reaction 8,14,15 retaining the microstructural features of the precursor.…”

Section: Introductionmentioning

confidence: 99%

Tribomechanical modification of Bi promoted vanadyl phosphate systems 1: An improved catalyst and insight into structure–function relationship

Ayub

Willinger

Харламов

et al. 2003

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Bi promoted VOHPO 4 ·0.5H 2 O (Bi-VHP) was mechanically treated in ethanol and air for several times and the morphology was studied by several characterisation techniques such as SEM, TEM, EELS, BET and XRD. The data were compared to those from the reference sample (Bi-VHP unmilled) and to those from a sample thermally treated in vacuum. The equilibrated product (VO) 2 P 2 O 7 (VPP), that was obtained from Bi promoted VOHPO 4 ·0.5H 2 O was included in the comparison. SEM shows that the reference sample consists mainly of flat smooth needles, that form a blossom secondary morphology. Under mechanical treatment the secondary morphology is lost and packages form with coin-shape particles. XRD revealed that milling in ethanol for 5 min reduced the particle size but did not change the phase. Milling in air for 28 min resulted in an amorphous phase, whereas treatment above 30 min led to crystalline VPP. Thermal activation induced a phase change to VPP with the initial material still being present as a minority phase. The ball mill method is effective for catalysts activation as it increases the specific surface area and hence activity and selectivity per volume. On the other hand ball milling destroys the crystallinity and reduces the conversion and yield per unit surface area.

show abstract

Section: Introductionmentioning

confidence: 99%

Tribomechanical modification of Bi promoted vanadyl phosphate systems 1: An improved catalyst and insight into structure–function relationship

Ayub

Willinger

Харламов

et al. 2003

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Another effect of Cr doping is to increase T N from 150 K in stoichiometric V 2 O 3 to ϳ181 K in our samples. Single crystals of ͑V 12x Cr x ͒ 2 O 3 with different Cr doping were grown at Purdue University using a skull melting technique [9]. The stoichiometry of the crystals used in this study was determined to be x 2.8% by electron probe microanalysis.…”

mentioning

confidence: 99%

Orbital Occupancy Order inV2O3: Resonant X-Ray Scattering Results

et al. 1999

View full text Add to dashboard Cite

Resonant x-ray scattering experiments at the vanadium K edge demonstrate the existence of orbital ordering in V 2 O 3 . Bragg peaks due to the long-range order of 3d orbitals occupancy are observed when the photon energy is tuned to the threshold of the vanadium 3d bands. The azimuthal dependence of the resonant intensities confirms that the resonance arises from the ordering of the vanadium orbital occupancy. The observed orbital structure accounts for the complex magnetic structure of V 2 O 3 . The measured magnetic and orbital responses have the same critical temperature T N .[S0031-9007 (99)09287-X] PACS numbers: 78.70.Ck, 71.30. + h, 75.50.EeTwenty years ago, Castellani et al. [1] proposed that long-range order in the occupancy of the vanadium 3d orbitals was responsible for the complex magnetic properties of V 2 O 3 . Upon doping with Cr and/or under the application of hydrostatic pressure [2,3] V 2 O 3 exhibits both insulating and metallic phases with peculiar magnetic correlations [4][5][6]. It was suggested [1] that the spatial ordering of the occupancy of degenerate electronic orbitals accounts for the anisotropic exchange integrals found in the antiferromagnetic insulator phase (AFI) [5]. Furthermore, fluctuations in the orbital occupancy have been invoked to explain the evolution of the magnetic correlations in various phases of the V 2 O 3 system [6]. It appears that orbital occupancy plays a central role in the physics of V 2 O 3 , but no direct proof for orbital order could be produced experimentally since the original proposal in the late 1970s.In this Letter we present resonant x-ray scattering (RXS) experiments at the K edge of vanadium that demonstrate unambiguously the existence of orbital order in V 2 O 3 and provide information on the type of ordering. RXS is sensitive to the occupancy of electronic orbitals because it probes the symmetry of vacant electronic states through resonant multipole electric transitions; the variation of the orbital resonant scattering cross section with the direction of the incident polarization (azimuthal angle F) reflects the spatial symmetry of ordered orbitals. Furthermore, RXS may be tuned to probe selectively the electronic shells where orbital order takes place. In the case of V 2 O 3 , theoretical calculations [7] have shown that the resonance at the vanadium K edge provides observable cross sections arising from the order of the 3d vanadium states.RXS experiments were performed at the ID20 magnetic scattering undulator beam line at the European Synchrotron Radiation Facility [8]. A double crystal, Si(111), monochromator located between two focusing mirrors defined a narrow energy band around the vanadium K edge (FHWM 0.8 eV) with a high degree of linear s polarization. The x-ray beam was diffracted by the sample onto a pyrolitic graphite crystal analyzer [(004) reflection] to separate the s and p components of the scattered radiation. The sample was mounted with beeswax in a closed cycle refrigerator which could be rotated about the scattering vector to p...

show abstract

“…This stereochemistry was retained throughout the subsequent reactions [12]. This stereochemistry was retained throughout the subsequent reactions [12].…”

Section: Synthesis Of Polyanion-pt-complexesmentioning

confidence: 86%

Synthesis and Antitumor Activity of Polyanion-Pt-Complexes Containing Alicyclic Amines as Ligands

Han

Park

Cho

et al. 1994

Journal of Bioactive and Compatible Polymers

View full text Add to dashboard Cite

Four polyanion-Pt(II)-complexes, PEE-cis-DACH-Pt, PEE-cis -(ACP) 2 -Pt, PCR-cis -DACH-Pt, and PCR-cis -(ACP) 2 -Pt, were synthesized by the reactions of polyanions such as poly[(2-ethoxytetrahydropyran-5,6-diyl)(1,2dicarboxyethylene)](PEE) and poly[(3,4-dicarboxytetrahydropyran-2,6-diyl)-(1,2-dicarboxypropylene)](PCP) with cis -[Pt(amine) 2 ) 2 ](NO 3 ) 2 , where the amine was 1,2-diaminocyclohexane (DACH) or aminocyclopropane (ACP). The biological activities of the complexes were measured in vitro against A-459 nonsmall cell lung, Sk-OV-3 ovarian, SK-Mel-2 melanoma, XF-498 CNS, and HCT-15 colon tumor cell lines. The increased life span was measured against L1210 leukemia and found to be 223% for PCP-cis -(ACP) 2 -Pt(II) at the dose of 25 mg/Kg.

show abstract

Recent Advances In Air Pollution Analysis

Cited by 7 publications

References 298 publications

Tribomechanical modification of Bi promoted vanadyl phosphate systems 1: An improved catalyst and insight into structure–function relationship

Tribomechanical modification of Bi promoted vanadyl phosphate systems 1: An improved catalyst and insight into structure–function relationship

Orbital Occupancy Order inV2O3: Resonant X-Ray Scattering Results

Synthesis and Antitumor Activity of Polyanion-Pt-Complexes Containing Alicyclic Amines as Ligands

Contact Info

Product

Resources

About