The Long Spacing in Rubber

1942 ◽  
Vol 15 (4) ◽  
pp. 780-783
Author(s):  
Adolf Schallamach
Keyword(s):  
Equatorial Plane ◽  
Fibre Axis ◽  
X Ray ◽  
Wide Tube ◽  
Different Origin

Abstract The x-ray diagrams of some rubbers give a long spacing, which was first reported by Clark and collaborators. According to them, it is found only in gel rubber, where it has the value of 54 a.u., but it is absent in sol rubber. This spacing is oriented in stretched rubber, the x-ray reflections contracting into two spots in the equatorial plane. This means that the long spacings lie in planes at right angles to the fibre axis. As we found it difficult to account for this result and, furthermore, had indications that this long spacing might depend on the nature of the rubber, we examined a number of specimens of different origin and preparation. We used a camera of about 10-inch radius, reducing the air scattering by inserting an evacuated length of wide tube with thin cellophane windows at both ends. The x-ray source in these experiments was the 50 kw. x-ray generator of this laboratory, working with an input of 30 to 40 kw.

scholarly journals The Chemistry of Heteroarylphosphorus Compounds, Part 16.+ An X-Ray Structural Study of (2-Thienyl)bis(2,2′-biphenylylene)phosphorane. A Comparison with Related Methyl and Aryl bis(2,2′-biphenylylene)- spirophosphoranes

1983 ◽  
Vol 38 (4) ◽  
pp. 465-469 ◽  
Author(s):  
David W. Allen ◽  
Lorraine A. March ◽  
Ian W. Nowell ◽  
John C. Tebby
Keyword(s):  
Least Squares ◽  
Electron Density ◽  
Structural Study ◽  
Equatorial Plane ◽  
Title Compound ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Thienyl Group ◽  
Density Methods ◽  
Least Squares Techniques

AbstractCrystals of the title compound are monoclinic, a= 18.9 93 (11), b = 8.757(5), c= 13.267(8) Å, β = 106.60(5)°, Z = 4 in space group Cc (Cs4 , No. 9). The structure was determined by Patterson and electron-density methods and refined by least squares techniques to R= 0.081, R′ = 0.085 for 1293 independent reflections classified as observed. The molecule is found to adopt an almost regular trigonal bipyramidal geometry in which the two biphenylylene units span apical-equatorial positions and the 2-thienyl group occupies the remaining equatorial site. The 2-thienyl group, which is disordered, does not lie in the equatorial plane, and there is no indication of C2pπ → P3dπ-t interactions between the heteroaryl group and phosphorus. The steric requirements of the 2-thienyl group appear to be comparable with those of methyl and phenyl groups in bis(2,2′-biphenylylene)spiro-phosphoranes.

scholarly journals Structural and Mechanical Strength of Proton Radiation Processed Polyethylene Terephthalate

2020 ◽  
Vol 12 (1) ◽  
pp. 83-91
Author(s):  
M. Sahoo ◽  
B. Mallick ◽  
S. Rout ◽  
G. N. Dash
Keyword(s):  
Mechanical Strength ◽  
Polyethylene Terephthalate ◽  
Fibre Axis ◽  
Diffraction Spectrum ◽  
Proton Radiation ◽  
Radiation Processing ◽  
X Ray ◽  
Mesophase Formation ◽  
Extra Peak ◽  
Radiation Induced

The change in structural and mechanical behavior of polyethylene terephthalate (PET) due to 2.4 MeV proton has been studied. Radiation processing of PET polymer is carried out using different low doses such as 0.2, 2.0, and 20 kGy. The Physics of microstrain and radiation-induced mesophase formation are analysed. X-ray investigation indicates that  proton-induced structural modification takes place in the material. Apart from usual diffraction peaks, a low intensity broad peak is observed at small angle of about 2q =10º, when the fibre axis is mounted parallel to the X-ray direction. Such peak is absent in the diffraction spectrum when the fibre axis is mounted perpendicular to the beam direction. The appearance of the extra peak in a particular orientation confirms that, the phase is 2-dimensionally oriented (mesophase). The Young’s modulus (Y) of this irradiated PET sample is found to be more than that of the virgin sample with the highest value recorded for a dose of 2.0 kGy. The decrease in Y for higher dose (20 kGy) may be due to enhanced ion-induced microstrain in the sample, causing degradation in mechanical strength.

Crystal structure of Aquatetrakis(N-formylpiperidine)dioxouranium(VI) Bisperchlorate

1980 ◽  
Vol 33 (1) ◽  
pp. 69 ◽  
Author(s):  
GJ Honan ◽  
DL Kepert ◽  
SF Lincoln ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Single Crystal ◽  
Least Squares ◽  
Equatorial Plane ◽  
Title Compound ◽  
Organic Ligands ◽  
X Ray Diffraction ◽  
Uranyl Compounds ◽  
X Ray

The crystal structure of the title compound, [UO2{OCHN(CH2)5}4(H2O)] (ClO4)2, has been determined by single-crystal X-ray diffraction at 295 K and refined by least squares to a residual of 0.051 for 3113 'observed' reflections. Crystals are monoclinic, C2/c, a 16.945(2), b 12.711(2), c 17.304(2)Ǻ, β 107.76(1)°, Z 4. The uranyl moiety [U=O, 1.76(2)Ǻ] is five-coordinated in the equatorial plane by the water molecule [U-O, 2.436(8)Ǻ] and four organic ligands [U-O, 2.379(8), 2.396(13)Ǻ]. The angles O-U-O in the equatorial plane range from 70.3(3) to 73.6(3)°; O=U-0 range between 86.7 and 95.3°. The angle O=U=O is 177.8(3)°. The stereochemistry of seven-coordinate uranyl compounds is examined by using repulsion theory.

AN ATOMIC BASIS STUDY ON CANCER: - HERB MEDICINE ADDITIVE LANTHANIDE-HPD LOCALIZATION IN ANIMAL TUMOR -

1992 ◽  
Vol 02 (04) ◽  
pp. 535-546 ◽  
Author(s):  
CHAU-CHIN WEI ◽  
YASUO TOMINAGA ◽  
JUI-CHANG TSAI ◽  
CHEE-YIN CHAI ◽  
WU-SIUNG WU
Keyword(s):  
Detection Method ◽  
Rare Earth Metals ◽  
Chinese Herb ◽  
Animal Experiments ◽  
Emission Analysis ◽  
X Ray ◽  
Animal Tumor ◽  
Cancer Lesion ◽  
Different Origin ◽  
Specific Experiment

The particle induced X-ray emission analysis is applied to mark (or to localize) a cancer lesion from its benign environment in animal experiments. As a photosensitiser, we have used hematoporphyrin derivative (HPD) and in order to make HPD visible to PIXE, we synthesize HPD with rare earth metals to form lanthanide-HPD to enhance the localizing efficiency tremendously and PIXE is used as a straightforward detection method to find the successfulness of the synthesis. In theory, this approach can be used to probe carcinogenesis at cell levels. To increase the cure effects of lanthanide-HPD, we add ZYX to enhance the pharmaceutical effectiveness. ZYX, our code name for a group of drugs and chemicals, is mostly of the Chinese herb extraxctions but some has different origin. We explain the present approach with a specific experiment, Dysprosium-HPD (Dy-HPD) as a localizer, and conclude this article with some comments and perspectives.

scholarly journals The Be/X-ray transient V0332+53: evidence for a tilt between the orbit and the equatorial plane?

1999 ◽  
Vol 307 (3) ◽  
pp. 695-702 ◽  
Author(s):  
I. Negueruela ◽  
P. Roche ◽  
J. Fabregat ◽  
M. J. Coe
Keyword(s):  
Equatorial Plane ◽  
X Ray

scholarly journals 2D Relativistic MHD Simulations of PWNe: Preliminary Results

2004 ◽  
Vol 218 ◽  
pp. 179-180
Author(s):  
Elena Amato ◽  
Luca Del Zanna ◽  
Niccolò Bucciantini
Keyword(s):  
High Resolution ◽  
Wind Energy ◽  
Energy Distribution ◽  
Equatorial Plane ◽  
Detailed Comparison ◽  
X Ray ◽  
Preliminary Results ◽  
Mhd Simulations ◽  
X Ray Imaging ◽  
Simulation Results

We present preliminary results of 2D axisymmetric relativistic MHD simulations of PWNe, aimed at investigating whether structures such as the rings and jets revealed by high resolution X-ray imaging can be due to anisotropy of the outflow from the pulsar. We confirm that these features can qualitatively be explained when the energy flux is larger in the equatorial plane than along the spin axis. Detailed comparison between simulation results and observations is required to constrain the wind energy distribution upstream of the termination shock.

scholarly journals The Remarkable Binary Pulsar PSR B1259–63

2000 ◽  
Vol 177 ◽  
pp. 521-526
Author(s):  
Simon Johnston
Keyword(s):  
Orbital Period ◽  
Equatorial Plane ◽  
Dispersion Measure ◽  
Scattering Parameters ◽  
X Ray ◽  
Unique System ◽  
Rotation Measure ◽  
Be Star ◽  
Future Work

AbstractPSR B1259–63 is a unique system consisting of a young radio pulsar in orbit about a 10 M⊙Be star. Its orbital period is 3.4 yr and the eccentricity close to 0.9. Around periastron, the system is a radio and X-ray transient and shows changes in flux density, dispersion measure, rotation measure and scattering parameters on very short timescales. Timing observations show the equatorial plane of the Be star and the plane of the orbit are not aligned and the orbit precesses as a result. I briefly summarise 10 years of radio observations of PSR B1259–63 and the implications of these observations. Future work includes the determination of the orbital size through VLBI and observations at TeV energies.

New Complexes of Molybdenum(II) and Tungsten(II) with a C,N-Chelated Stannylene

2007 ◽  
Vol 72 (5-6) ◽  
pp. 629-636 ◽  
Author(s):  
Zdeňka Padělková ◽  
Ivana Císařová ◽  
Karla Fejfarová ◽  
Jana Holubová ◽  
Aleš Růžička ◽  
...  
Keyword(s):  
Transition Metal ◽  
Equatorial Plane ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Forming ◽  
Nitrogen Donor ◽  
And Tungsten

Two new complexes of [Sn{2-[(CH3)2NCH2]C6H4}2] with [Mo(η5-C5H5)(CO)3Cl] and [W(η5-C5H5)(CO)3Cl], respectively, were prepared via insertion of stannylene into the Mo-Cl or W-Cl bond forming thus the transition metal-tin bond. These complexes were studied by IR, NMR and X-ray diffraction techniques. The tin atom in these complexes is five-coordinated with the carbon atoms of ligands and transition metal in equatorial plane and the chlorine and the nitrogen donor atoms in axial positions. The attempts to photolyse, reduce or fluorinate the prepared complexes and characterize the products of these reactions failed.

scholarly journals Transition metal complexes with thiosemicarbazide-based ligand: Part 45 - Synthesis, crystal and molecular structure of [2, 6-diacetylpyridine bis(S-methylisothiosemicarbazonato)]diazide-iron(III)

2003 ◽  
Vol 68 (4-5) ◽  
pp. 425-433 ◽  
Author(s):  
Vukadin Leovac ◽  
Vladimir Divjakovic ◽  
Valerija Cesljevic ◽  
Refik Fazlic
Keyword(s):  
Molecular Structure ◽  
Transition Metal ◽  
Transition Metal Complexes ◽  
Equatorial Plane ◽  
Crystal And Molecular Structure ◽  
Crystal Data ◽  
X Ray ◽  
High Spin Complex ◽  
Spin Complex ◽  
Template Reaction

The template reaction of a warm methanolic solution of FeCl3.6H2O S-methylisothiosemicarbazidehydroiodide and 2,6-diacetylpyridine in the presence of LiOAc and NaN3 yielded the high-spin complex [Fe(HL)(N3)2], were HL is the monoanion of the ligand 2,6-diacetylpyridine bis(S-methylisothiosemicarbazone). X-Ray analysis of the complex showed its pentagonal-bipyramidal configuration, with pentadenate (N5) HL in the equatorial plane and two monodentate azide groups in the axial positions. Crystal data are: monoclinic, P21/c,a=1.0263(2), b = 1.2525(2), c = 1.6660(3) nm, ?= 98.94?, V = 2.1154 nm3, Z = 4, ?x = 1.499 g cm-3, ?0 = 1.48 g cm-3, F(000) = 984, ?= 9.40 cm-1.

scholarly journals From the earliest pulses to the latest flares in long gamma-ray bursts

2018 ◽  
Vol 615 ◽  
pp. A80
Author(s):  
A. Pescalli ◽  
M. Ronchi ◽  
G. Ghirlanda ◽  
G. Ghisellini
Keyword(s):  
Spectral Properties ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Peak Time ◽  
Emission Pulse ◽  
X Ray ◽  
Temporal Properties ◽  
Central Engine ◽  
Prompt Emission ◽  
Different Origin

The prompt emission of gamma-ray bursts extends from the early pulses observed in γ-rays (>15 keV) to very late flares of X-ray photons (0.3–10 keV). The duration of prompt γ-ray pulses is rather constant, while the width of X-ray flares correlates with their peak time, suggesting a possibly different origin. However, pulses and flares have similar spectral properties. Considering internal and external shock scenarios, we derive how the energy and duration of pulses scale with their time of occurrence, and we compare this with observations. The absence of an observed correlation between the prompt emission pulse duration and its time of occurrence favours an “internal” origin and confirms earlier results. We show that the energetic and temporal properties of X-ray flares are also consistent with being produced by internal shocks between slow fireballs with a small contrast between their bulk Lorentz factors. These results relax the requirement of a long-lasting central engine to explain the latest X-ray flares.

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