scholarly journals THE NUCLEAR SPIN RESONANCE SPECTRUM OF Al27 IN SPODUMENE

1958 ◽  
Vol 36 (10) ◽  
pp. 1295-1307 ◽  
Author(s):  
L. B. Robinson
Keyword(s):  
Nuclear Spin ◽  
Resonance Spectrum ◽  
Companion Paper ◽  
Quadrupole Interactions ◽  
Resonance Frequencies ◽  
Spin Resonance ◽  
Theoretical Predictions ◽  
Induction Type ◽  
First Time ◽  
Good Agreement

An experimental study has been made of the nuclear spin resonance spectrum of Al27 in a single crystal of spodumene (LiAl(SiO3)2) over a range of external magnetic field H0 wide enough [Formula: see text] to bridge for the first time the gap between pure quadrupole spectra (R = 0) and Zeeman spectra slightly perturbed by quadrupole interactions [Formula: see text]. Experimental results on the resonance frequencies and relative signal amplitudes obtained with an induction type of nuclear resonance spectrometer are described, and are found to be in good agreement with the theoretical predictions given in the preceding companion paper.

Quad Band Planar Inverted F Antenna for Smart Phone

2014 ◽  
Vol 573 ◽  
pp. 394-399
Author(s):  
R. Manikandan ◽  
P.K. Jawahar
Keyword(s):  
High Frequency ◽  
Smart Phone ◽  
Analysis And Design ◽  
High Frequency Structure Simulator ◽  
Low Profile ◽  
Resonance Frequencies ◽  
Theoretical Predictions ◽  
Communication Devices ◽  
Device Miniaturization ◽  
Good Agreement

In recent years, the demand for compact handheld communication devices has grown significantly. For device miniaturization antenna size is to be reduced. Micro strip and PIFA have been used for past few years. Since it has low profile geometry it can be embedded into devices. This project is to develop a Quad band small size Planar Inverted F Antenna (PIFA) for the operation in modern multi-band mobile transceiver system. Various techniques for analysis and design of such antenna investigated in this project. The design curve is used to design Quad band Planar inverted F Antenna to operate at the 900, 1800, 2100 and 3500 MHz bands. Since High Frequency Structure Simulator (HFSS) simulation result agrees well with the theoretical predictions, this project also designed through HFSS. An antenna designed at the four desired band and optimized to adjust the four resonance frequencies using HFSS simulation. The substrate FR4 (εr=4.4 & tanδ = 0.02) are in good agreement with the simulation result. Further bandwidth enhancements by making defects in the substrate at particular area were need of much reflection.

scholarly journals A theoretical analysis of the semileptonic decays $$\eta ^{(\prime )}\rightarrow \pi ^0l^+l^-$$ and $$\eta ^\prime \rightarrow \eta l^+l^-$$

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Rafel Escribano ◽  
Emilio Royo
Keyword(s):  
Theoretical Analysis ◽  
Semileptonic Decays ◽  
Coupling Constants ◽  
Energy Spectra ◽  
Radiative Decays ◽  
Vector Meson Dominance ◽  
Decay Widths ◽  
Theoretical Predictions ◽  
First Time ◽  
Good Agreement

AbstractA complete theoretical analysis of the C- conserving semileptonic decays $$\eta ^{(\prime )}\rightarrow \pi ^0l^+l^-$$ η ( ′ ) → π 0 l + l - and $$\eta ^\prime \rightarrow \eta l^+l^-$$ η ′ → η l + l - ($$l=e$$ l = e or $$\mu $$ μ ) is carried out within the framework of the Vector Meson Dominance (VMD) model. An existing phenomenological model is used to parametrise the VMD coupling constants and the associated numerical values are obtained from an optimisation fit to $$V\rightarrow P\gamma $$ V → P γ and $$P\rightarrow V\gamma $$ P → V γ radiative decays ($$V=\rho ^0$$ V = ρ 0 , $$\omega $$ ω , $$\phi $$ ϕ and $$P=\pi ^0$$ P = π 0 , $$\eta $$ η , $$\eta ^{\prime }$$ η ′ ). The decay widths and dilepton energy spectra for the two $$\eta \rightarrow \pi ^0l^+l^-$$ η → π 0 l + l - processes obtained using this approach are compared and found to be in good agreement with other results available in the published literature. Theoretical predictions for the four $$\eta ^{\prime }\rightarrow \pi ^0l^+l^-$$ η ′ → π 0 l + l - and $$\eta ^\prime \rightarrow \eta l^+l^-$$ η ′ → η l + l - decay widths and dilepton energy spectra are calculated and presented for the first time in this work.

scholarly journals Measurements of Properties of Antihydrogen

2018 ◽  
Vol 46 ◽  
pp. 1860069
Author(s):  
Art Olin ◽  
Keyword(s):  
Hyperfine Splitting ◽  
Resonance Spectrum ◽  
Theoretical Framework ◽  
Fundamental Symmetries ◽  
Antihydrogen Atom ◽  
A Value ◽  
Spin Resonance ◽  
The Masses ◽  
Bounded Below ◽  
First Time

The ALPHA project at the CERN AD is testing fundamental symmetries between matter and antimatter using trapped antihydrogen atoms. The spectrum of the antihydrogen atom may be compared to ordinary hydrogen where it has been measured very precisely. CPT conservation, which underpins our current theoretical framework, requires equality of the masses and charges of matter and its antimatter partners, so antihydrogen spectroscopy presents a path to precision CPT tests. I will discuss the techniques used by ALPHA to trap more than 8000 antihydrogen atoms in 2016, and interrogate them for 600s. The 1S-2S transition in antihydrogen has been observed for the first time, and it agrees with its hydrogen counterpart within an uncertainty of 400 kHz or 0.2 ppb. The charge of the antihydrogen atom has been bounded below [Formula: see text]. A value of 1420.4 0.5MHz for the hyperfine splitting has been obtained from observation of the positron spin resonance spectrum.

Performance enhancement of MEMS-guided four beam piezoelectric transducers for energy harvesting and acceleration sensing

2019 ◽  
Vol 33 (18) ◽  
pp. 1950192 ◽  
Author(s):  
Hossein Ghoddus ◽  
Zoheir Kordrostami ◽  
Peyman Amiri
Keyword(s):  
Output Voltage ◽  
Performance Enhancement ◽  
Piezoelectric Transducers ◽  
Maximum Output ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Resonance Frequencies ◽  
First Time ◽  
Piezoelectric Acceleration ◽  
Good Agreement

In the present paper, guided four beam (G4B) piezoelectric transducers with enhanced sensitivities have been designed. Based on the suggested G4B structures, piezoelectric energy harvesters (PEHs) and acceleration transducers with higher voltages than their previously reported counterparts and with lower displacements than the single-cantilever PEHs (SC-PEHs) have been proposed. We have shown that it is possible to arrive at much more output voltages in comparison with the conventional PEHs by redesigning the structure of the cantilever beams. In 1 g acceleration, the maximum output voltage obtained from the proposed PEHs has been 13.49 V whereas the output voltage for the conventional G4B-PEH is 2.87 V. This paper for the first time proposes G4B-PEHs with smaller displacements and larger voltages compared to a SC-PEH. The same G4B framework has been studied as a piezoelectric acceleration transducer. The effect of piezoelectric length on the extracted voltage in both unimorph and bimorph cantilevers has been discussed and the optimized length has been calculated. An analytical method is developed to compute the resonance frequencies of different beam shapes whose results are in a good agreement with numerical simulations.

Endor Spectroscopy on Deep Level Defects in Gaas

1987 ◽  
Vol 104 ◽  
Author(s):  
J.-M. Spaeth ◽  
A. Gorger ◽  
D. M. Hofmann ◽  
B. K. Meyer
Keyword(s):  
Deep Level ◽  
Double Resonance ◽  
Thermal Conversion ◽  
Electron Nuclear Double Resonance ◽  
Endor Spectroscopy ◽  
Spin Resonance ◽  
Pair Defect ◽  
Theoretical Predictions ◽  
Optically Detected ◽  
First Time

ABSTRACTWith optically detected electron spin resonance (ODESR) and electron nuclear double resonance (ODENDOR) the following deep level defects in s.i. LEC-grown GaAs were investigated: EL2 defects in undoped GaAs and VGa2+ and VGa3+ defects in V-doped GaAs. This paper summarizes the major results: (i) the double donor defect EL2 in an (AsGa-Asi+) pair defect, which is distributed rather homogeneously across an as-grown wafer. After inverted thermal conversion treatment it is destroyed, and 3 new paramagnetic defects appear. EL2 is recovered after annealing at ca. 800 °C, while the 3 new defects disappear. (ii) A new ESR spectrum due to VGa2+ was measured. It is shown for the first time for a 3dn impurity in semiconductors that VGa3+(3d3)is in a low spin state (S = 1/2) in accordance with recent theoretical predictions. A deep level defect at Ev + (0.2–0.4) eV is discovered, which is probably the defect needed for explaining the s.i. properties of V-doped GaAs.

X-ray induced conductivity in insulating materials

1956 ◽  
Vol 236 (1207) ◽  
pp. 464-480 ◽  
Keyword(s):  
Ionizing Radiation ◽  
Amorphous Materials ◽  
Physical Parameters ◽  
Free Electrons ◽  
Insulating Materials ◽  
X Ray ◽  
Theoretical Predictions ◽  
First Time ◽  
Good Agreement ◽  
Trapping Sites

A co-ordinated explanation of the conductivity induced by ionizing radiation in solid insulating materials (conductivity ~ 10 -20 Q -1 cm -1 ), including amber, mica and a number of plastics, is put forward for the first time. A model based on conduction by free electrons and including the presence of electron traps is proposed, and the theoretical predictions based thereon are shown to be in good agreement with the experimental results. The dependence of induced conductivity and of the subsequent decay upon temperature and dose rate have been investigated. Physical parameters are given for each material: recombination crosssection, number of traps and their distribution in energy, mean distance diffused by free electrons and probability factors of release from traps. The results suggest that when crystalline regions are present in a material (e.g. polyethylene), the boundaries of these regions provide trapping sites in addition to traps of unspecified nature which are present in completely amorphous materials.

scholarly journals 3D simulations of internal gravity waves in solar-like stars

2013 ◽  
Vol 9 (S301) ◽  
pp. 375-376
Author(s):  
Lucie Alvan ◽  
Allan Sacha Brun ◽  
Stéphane Mathis
Keyword(s):  
Numerical Simulations ◽  
Gravity Waves ◽  
Rotation Rate ◽  
Spherical Harmonic ◽  
Internal Gravity Waves ◽  
3D Simulations ◽  
Frequency Splitting ◽  
Theoretical Predictions ◽  
First Time ◽  
Good Agreement

AbstractWe perform numerical simulations of the whole Sun using the 3D anelastic spherical harmonic (ASH) code. In such models, the radiative and convective zones are non-linearly coupled and in the radiative interior a wave-like pattern is observed. For the first time, we are thus able to model in 3D the excitation and propagation of internal gravity waves (IGWs) in a solar-like star's radiative zone. We compare the properties of our waves to theoretical predictions and results of oscillation calculations. The obtained good agreement allows us to validate the consistency of our approach and to study the characteristics of IGWs. We find that a wave's spectrum is excited up to radial order n=58. This spectrum evolves with depth and time; we show that the lifetime of the highest-frequency modes must be greater than 550 days. We also test the sensitivity of waves to rotation and are able to retrieve the rotation rate to within 5% error by measuring the frequency splitting.

Charge-Transfer Interactions of Aliphatic Amino Acids with Metal Ions

1971 ◽  
Vol 26 (11) ◽  
pp. 1098-1101 ◽  
Author(s):  
Wolfgang Lohmann
Keyword(s):  
Amino Acids ◽  
Charge Transfer ◽  
Charge Transfer Complex ◽  
Resonance Spectrum ◽  
Straight Line ◽  
Spin Resonance ◽  
A Charge ◽  
Prosthetic Groups ◽  
Good Agreement

The effect of various non-SH-containing amino acids on an electron spin resonance spectrum as well as on an optical absorption spectrum of an aqueous copper (II) solution was investigated. The data obtained indicate that a charge-transfer complex is formed with amino acids acting as electron donors. A plot of the wavelength of the CT-band vs. the pK values of the carboxyl group exhibits a straight line with the larger pK values appearing at shorter wavelengths. Similar results were obtained when the intensity was plotted vs. the pK values of the amino group; again, higher pK values correspond to lower intensities. Thus, the method allows the determination of the pK values of prosthetic groups of amino acids. The data obtained are in good agreement with the CT-theory.

Probing the distant galaxy cluster JKCS 041 on the L − T − M scaling relations

2018 ◽  
Vol 8 (1) ◽  
pp. 28-33
Author(s):  
Iu. Babyk ◽  
Keyword(s):  
Galaxy Cluster ◽  
Scaling Relations ◽  
Physical Parameters ◽  
Distant Galaxy ◽  
X Ray ◽  
Concentration Parameter ◽  
Theoretical Predictions ◽  
Virial Mass ◽  
First Time ◽  
Good Agreement

The detailed X-ray analysis of the distant galaxy cluster JKCS 041 is presented. We use deep (~75 ks) archived data of X-ray Chandra Observatory to extract the main physical characteristic for one of the most distant galaxy cluster known to date. We investigate the imaging and spectral properties of JKCS 041. We explore its surface brightness, density, entropy, cooling time, and mass profiles. The temperature of JKCS 041 is equal to 7.4 ± 2.9 keV while the total virial mass is M200 = (4.6 ± 2.9) × 1014MSun. The gas fraction is ~10% while the dark matter is ~90% at R200. We use the obtained physical parameters of JKCS 041 to build numerous X-ray scaling relations. By adding JKCS 041 parameters we increase the redshift of our previous cluster’s sample from 1.4 to 1.8. We study the three classical relations between temperature, luminosity and total mass, and two additional. We find the concentration parameter of JKCS 041, build c − M relation and compare them with current hydrodynamic simulations. In addition, we explore, for the first time in the case of distant objects, the M − Y = T · Mg relation which is one of the most robust mass estimators. We conclude that concentration parameter, c, of JKCS 041 is in a good agreement with theoretical predictions. The obtained X-ray scaling relations were used to probe their evolution. We find that our results show inconsistent with self-similar evolution models.

An E.S.R. study of natural fluorite containing manganese impurities

1974 ◽  
Vol 39 (306) ◽  
pp. 705-708 ◽  
Author(s):  
A. D. Bailey ◽  
R. P. Hunt ◽  
K. N. R. Taylor
Keyword(s):  
Electron Spin Resonance ◽  
Energy Level ◽  
Electron Spin ◽  
Resonance Spectrum ◽  
Manganese Ions ◽  
Synthetic Material ◽  
Broken Hill ◽  
Spin Resonance ◽  
Ionic Energy ◽  
Good Agreement

SummaryThe electron spin resonance spectrum of a sample of natural, orange-coloured fluorite from Broken Hill, Australia, has been observed and shown to arise from the presence of manganese ions. From an analysis of the structure of this spectrum it has been possible to estimate the various contributions to the ionic energy level splitting and to show that these are in good agreement with comparable results for synthetic material. It is evident that the manganese ions have entered the lattice substitutionally at Ca2+ sites and the nature of this site is discussed.

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