scholarly journals Reaction Dynamics of Electronically Excited Calcium Atom

1992 ◽  
Vol 12 (1-2) ◽  
pp. 123-136 ◽  
Author(s):  
E. Verdasco ◽  
M. Menéndez ◽  
M. Garay ◽  
A. González Ureña ◽  
O. Benoist D'azy ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Collision Energy ◽  
Low Voltage ◽  
Relative Concentration ◽  
Reaction Dynamics ◽  
The Other ◽  
Calcium Atom ◽  
Dc Discharge ◽  
Electronically Excited

Absolute values of the total chemiluminescence cross-section for the beam-gas Ca(3P, 1D) + Cl4C → CaCl(A, B) + Cl3C and Ca(3P, 1D) + SF6 → CaF(A, B) + SF5 reactions have been measured at low collision energy, ET = 0.15 and 0.14eV, respectively. Both metastable atomic calcium states Ca(3P, 1D) were produced under low voltage dc-discharge conditions. By changing the discharge conditions, different metastable concentrations were produced to measure the state-to-state cross-section for both 3P and 1D reactions. The following values for the total chemiluminescence cross-sections were obtained:σD1 = 1.77 Å and σP3 = 0.25 Å for the Ca(3P, 1D) + Cl4C → CaCl(A, B) + Cl3C reaction.σD1 = 0.59 Å2 and σP3 = 0.56 Å2 for the Ca(3P, 1D) + SF6 → CaF(A) + SF5 reaction.σD1 = 0.04 Å2 and σP3 = 0.12 Å for the Ca(3P, 1D) + SF6 → CaF(B) + SF5 reaction.In addition, beam-beam experiments were carried out at the same average low collision energy that of the beam-gas, and therefore, normalization between both experiments was possible. This procedure allowed us to obtain the excitation function of the Ca(1D) + SF6 reaction in absolute values over the 0.15–0.60eV collision energy range.On the other hand, by simulation, the ratio of CaCl(B-X/A-X) emissions intensities was found to be of 0.15. The variation of this ratio with the relative concentration of 1D/3P in a Broida oven leads to the conclusion that this state favours the formation of the B state in the chemiluminescent Ca(3P, 1D) + CH3CHCl2 → CaCl(A, B) + CH3CHCl reaction.

scholarly journals Reaction Dynamics of Translational and Electronic Excitation In Ca + SF6 Collisions

1989 ◽  
Vol 10 (1) ◽  
pp. 51-61 ◽  
Author(s):  
E. Verdasco ◽  
V. Saez Rabanos ◽  
A. Gonzalez Ureña
Keyword(s):  
Cross Section ◽  
Molecular Beam ◽  
Collision Energy ◽  
Electronic Excitation ◽  
Low Voltage ◽  
Reaction Dynamics ◽  
Laser Induced Fluorescence ◽  
The State ◽  
Calcium Atom ◽  
Ground Atom

Relative values of the total chemiluminescence cross.section for the crossed molecular beam Ca∗+SF6→CaF(A2Π)+SF6 reaction have been measured as a function of collision energy. Both metastable calcium atom states 3P1 were produced by low voltage de-discharge while translational excitation of the SF6 beam was achieved via the seeding technique. Whereas chemiluminescence yield from the CaF(A2Π) was observed from both of the metastable atom reactions, no chemiluminescence signal was detected from the ground atom reaction even though enough translational excitation was used to produc.e that excited product. By changing the discharge conditions different metastable concentrations were produced to measure the state-to-state cross-section for both 3P and 1D reactions, as a function of collision energy, up to 0.6 eV. Laser induced fluorescence of the atomic 4s5s 3S1←4s4p3PJ∘(J=0,1,2,3) lines have been measured to account for the metastable population in the J=1 level.

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

The Brittleness of Ebonite

1937 ◽  
Vol 10 (4) ◽  
pp. 778-786
Author(s):  
R. Ariano
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Cross Sections ◽  
Test Specimen ◽  
The State ◽  
The Other ◽  
Appreciable Effect ◽  
Considerable Influence ◽  
Minimum Depth ◽  
The Moment

Abstract The results of tests of the brittleness of ebonite are described. Resilience is influenced chiefly by the moment of inertia of the cross section of the test-specimen, but it seems also to be affected by the form of the specimen. The state of vulcanization has considerable influence on these mechanical properties within the undercured range, but with thorough vulcanization the state of cure plays no appreciable part. Notching of test-specimens is not of great importance. It diminishes the resilience, but when the tests are compared on a basis of equal moments of inertia of the resistant cross sections, this diminution becomes inappreciable in the case of brittle ebonites. On the other hand, the shape of the notch in ebonites containing no loading ingredients does influence the resilience. With V-shaped notches, the depth of the notch and its angle of aperture influence considerably the resilience of this latter type of ebonite, and notches of minimum depth are sufficient to have an appreciable effect.

QUASI-CLASSICAL TRAJECTORY STUDY OF THE REACTION PROBABILITY AND CROSS SECTION OF THE REACTION LiH + H

2013 ◽  
Vol 12 (01) ◽  
pp. 1250093 ◽  
Author(s):  
YULIANG WANG ◽  
JINCHUN ZHANG ◽  
BAOGUO TIAN ◽  
KUN WANG ◽  
XIAORUI LIANG ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Collision Energy ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Reaction Cross ◽  
Reaction Probability ◽  
Title Reaction ◽  
Reaction Cross Sections

Based on the new accurate potential energy surface of the ground state of LiH2 system. Quasi-classical trajectory (QCT) calculations were carried out for the reaction LiH + H . The reaction probability of the title reaction for J = 0 has been calculated. The reaction cross sections were calculated as functions of the collision energy in the range 0.1–2.5 eV. The results were found to be well consistent with the previous real wave packet (RWP) and QCT results.

Proton-proton scattering at the C. E. R. N. Intersecting Storage Rings

1973 ◽  
Vol 335 (1603) ◽  
pp. 431-452 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
High Energy ◽  
Storage Rings ◽  
The Other ◽  
Proton Scattering ◽  
High Energy Proton ◽  
Proton Proton ◽  
Total Cross Sections ◽  
Energy Proton

The main features of the C. E. R. N. Intersecting Storage Rings (I. S. R.) are reviewed, together with results obtained in 1971 and 1972 on elastic scattering and total cross-sections. The main result is a 10% increase of the total proton-proton cross-section in the I. S. R. energy range. The simplest picture of high energy proton-proton scattering which emerges from this and the other data, is briefly discussed.

scholarly journals Functional reconstitution of Chlamydomonas outer dynein arms from alpha-beta and gamma subunits: requirement of a third factor.

1994 ◽  
Vol 126 (3) ◽  
pp. 737-745 ◽  
Author(s):  
S Takada ◽  
R Kamiya
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Attachment Site ◽  
The Other ◽  
Wild Type ◽  
Heavy Chains ◽  
Sds Page ◽  
Gamma Subunits ◽  
Dynein Arms ◽  
Alpha Beta

The outer dynein arm of Chlamydomonas flagella, when isolated under Mg(2+)-free conditions, tends to dissociate into an 11 to 12S particle (12S dynein) containing the gamma heavy chain and a 21S particle (called 18S dynein) containing the alpha and beta heavy chains. We show here that functional outer arms can be reconstituted by the addition of 12S and 18S dyneins to the axonemes of the outer armless mutants oda1-oda6. A third factor that sediments at integral 7S is required for efficient reconstitution of the outer arms on the axonemes of oda1 and oda3. However, this factor is not necessary for reconstitution on the axonemes of oda2, oda4, oda5, and oda6. SDS-PAGE analysis indicates that the axonemes of the former two mutants lack a integral of 70-kD polypeptide that is present in those of the other mutants as well as in the 7S fraction from the wild-type extract. Furthermore, electron micrographs of axonemal cross sections revealed that the latter four mutants, but not oda1 or oda3, have small pointed structures on the outer doublets, at a position in cross section where outer arms normally occur. We suggest that the 7S factor constitutes the pointed structure on the outer doublets and facilitates attachment of the outer arm. The discovery of this structure raises a new question as to how the attachment site for the outer arm dynein is determined within the axoneme.

A QUASICLASSICAL TRAJECTORY STUDY OF REACTIVE SCATTERING ON AN ANALYTICAL POTENTIAL ENERGY SURFACE FOR GeH2 SYSTEM

2011 ◽  
Vol 10 (02) ◽  
pp. 147-163
Author(s):  
LI ZHANG ◽  
CHAO-YONG ZHU ◽  
GANG JIANG ◽  
CHAOYUAN ZHU ◽  
Z. H. ZHU
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Cross Section ◽  
Cross Sections ◽  
Collision Energy ◽  
Energy Surface ◽  
Life Time ◽  
Expansion Method ◽  
Reverse Reaction ◽  
Analytical Potential

A quasiclassical trajectory method was employed to study reaction Ge+H 2 (v=0, j=0) and reverse reaction H+GeH (v=0, j=0) on an analytical potential energy surface obtained from simplified many-body expansion method with fitting to B3P86/CC-pVTZ calculations around a global minimum and a long-range van de Waals well plus spectroscopy data for diatomic molecules GeH and H2 . Reaction probabilities from both reaction and reverse reaction were calculated. Dominant reaction is complex-forming reaction Ge+H2 (v=0, j=0) → GeH2 , and its cross section is 10 times bigger than that of complex-forming reaction from the reverse reaction. There is no threshold effect for complex-forming reaction and the cross sections for both complex-forming reactions decrease with the increase of collision energy. Life time of complex is shown to be decreasing with increase of collision energy. Dominant reverse reaction is reaction H + GeH (v=0,j=0) → Ge+H2 ; the reaction probability decreases with the increase of collision energy and differential cross section shows that this reverse reaction has almost equal angular distribution at low collision energy and mostly forward scattering at high collision energy.

scholarly journals A study by a double-refraction method of the development of turbulence in a long circular tube

1947 ◽  
Vol 192 (1028) ◽  
pp. 32-44 ◽  
Keyword(s):  
Reynolds Number ◽  
Weak Solution ◽  
Laminar Flow ◽  
Cross Section ◽  
Cross Sections ◽  
Circular Tube ◽  
Glass Tube ◽  
The Other ◽  
Double Refraction ◽  
Refraction Method

A streaming double-refraction method was employed to examine the flow in a long glass tube of a very weak solution of benzopurpurin in water. Two kinds of turbulent entry were used: with one, laminar flow at a Reynolds number of about 1900 was observed at cross-sections more than 120 diameters from the entry; with the other the corresponding distance was 90 diameters. The nature of the breakdown of laminar flow at a cross-section was found to depend upon the kind of entry and upon the distance of the cross-section from the inlet. The development of complete turbulence at various cross-sections was also investigated.

scholarly journals Curved composite beam with interlayer slip loaded by radial load

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
István Ecsedi ◽  
Ákos József Lengyel
Keyword(s):  
Linear Relationship ◽  
Cross Section ◽  
Cross Sections ◽  
Composite Beam ◽  
The Other ◽  
Radial Load ◽  
Rigid Plate ◽  
Shear Connection ◽  
First Case ◽  
Interlayer Slip

AbstractElastic two-layer curved composite beam with partial shear interaction is considered. It is assumed that each curved layer separately follows the Euler-Bernoulli hypothesis and the load slip relation for the flexible shear connection is a linear relationship. The curved composite beam at one of the end cross sections is fixed and the other end cross section is subjected by a concentrated radial load. Two cases are considered. In the first case the loaded end cross section is closed by a rigid plate and in the second case the radial load is applied immediately to it. The paper gives solutions for radial displacements, slips and stresses. The presented examples can be used as benchmark for the other types of solutions as given in this study.

scholarly journals Calculation of harmonic losses and ampacity in low-voltage power cables when used for feeding large LED lighting loads

2014 ◽  
Vol 3 (1) ◽  
pp. 50 ◽  
Author(s):  
N. J. Milardovich ◽  
L. Prevosto ◽  
M. A. Lara
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Low Voltage ◽  
High Harmonic ◽  
Frequency Domain Analysis ◽  
Element Analysis ◽  
Lighting Loads ◽  
Emission Limits ◽  
Phase Conductors ◽  
High Level

A numerical investigation on the harmonic disturbances in low-voltage cables feeding large LED loads is reported. A frequency domain analysis on several commercially-available LEDs was performed to investigate the signature of the harmonic current injected into the power system. Four-core cables and four single-core cable arrangements (three phases and neutral) of small, medium, and large conductor cross sections, with the neutral conductor cross section approximately equal to the half of the phase conductors, were examined. The cables were modelled by using electromagnetic finite-element analysis software. High harmonic power losses (up to 2.5 times the value corresponding to an undistorted current of the same rms value of the first harmonic of the LED current) were found. A generalized ampacity model was employed for re-rating the cables. It was found that the cross section of the neutral conductor plays an important role in the derating of the cable ampacity due to the presence of a high-level of triplen harmonics in the distorted current. The ampacity of the cables should be derated by about 40 %, almost independent of the conductor cross sections. The calculation have shown that an incoming widespread use of LED lamps in lighting could create significant additional harmonic losses in the supplying low-voltage lines, and thus more severely harmonic emission limits should be defined for LED lamps.

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