Superelastic electron scattering from calcium and lithium

1996 ◽  
Vol 74 (11-12) ◽  
pp. 984-990 ◽  
Author(s):  
P. J. O. Teubner ◽  
V. Karaganov ◽  
M. R. Law ◽  
P. M. Farrell
Keyword(s):  
Optical Pumping ◽  
Single Frequency ◽  
Optically Pumped ◽  
Close Coupling ◽  
Pumping System ◽  
State Orientation ◽  
Superelastic Scattering ◽  
Frequency Laser ◽  
Theory And Experiment ◽  
Good Agreement

Superelastic scattering experiment were performed on optically pumped calcium atoms at energies of 25.7 and 45 eV referred to the ground state. Orientation and alignment parameters derived from these experiments are compared with the predictions of several theories based on a distorted-wave formalism. The agreement between theory and experiment is unsatisfactory at the lower energy at all scattering angles. At the higher energy agreement improves at small scattering angles but is poor at middle angles. The results of our quantum electrodynamical calculation on optical pumping in lithium are compared with our observations. We find such good agreement between theory and experiment that we explore the possibility of superelastic scattering experiments on lithium atoms that are optically pumped with single-frequency laser light. A two-frequency pumping system is described and its use in the observation of superelastic scattering from lithium is discussed. Orientation and alignment parameters are presented at an equivalent energy of 21.8 eV for small angles. They are compared with those predicted by two close-coupling calculations. Excellent agreement is found between the present work and the convergent close-coupling theory of Bray.

scholarly journals MXene Core-Shell Nanosheets: Facile Synthesis, Optical Properties, and Versatile Photonics Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1995
Author(s):  
Yunjia Wang ◽  
Shunxiang Liu ◽  
Feng Zhu ◽  
Yiyu Gan ◽  
Qiao Wen
Keyword(s):  
Gold Nanoparticles ◽  
Research Work ◽  
Mode Locking ◽  
Single Frequency ◽  
Core Shell ◽  
Complex Structures ◽  
Facile Synthesis ◽  
Laser Applications ◽  
Saturable Absorbers ◽  
Frequency Laser

In recent years, the transition metal carbonitrides(MXenes) have been widely applied to photoelectric field, and better performance of these applications was achieved via MXene complex structures. In our work, we proposed a MXene core-shell nanosheet composed of a Ti2C (MXene) phase and gold nanoparticles, and applied it to mode-locked and single-frequency fiber laser applications. The optoelectronic results suggested that the performances of these two applications were both improved when MXene core-shell nanosheets were applied. As a result, we obtained a mode-locking operation with 670 fs pulses, and the threshold pump power reached to as low as 20 mW. Besides, a single-frequency laser with the narrowest linewidth of ~1 kHz is also demonstrated experimentally. Our research work proved that MXene core-shell nanosheets could be used as saturable absorbers (SAs) to promote versatile photonic applications.

Flow Characteristics of a Powder Lubricant in a Slider Bearing

2001 ◽  
Author(s):  
Manjunath Pappur ◽  
M. M. Khonsari
Keyword(s):  
Slip Velocity ◽  
Thrust Bearing ◽  
Volume Fraction ◽  
Flow Characteristics ◽  
Slider Bearing ◽  
Systematic Development ◽  
Powder Lubrication ◽  
Insight Into ◽  
Theory And Experiment ◽  
Good Agreement

Abstract This paper deals with a systematic development of theory of powder lubrication with the appropriate formalism based on the fundamentals of fluid mechanics. The theory is capable of predicting flow velocity, fluctuation (pseudo-temperature), powder volume fraction, and slip velocity at the boundaries. An extensive set of parametric simulations covering particle size, surface roughness, volumetric flow, load and speed are performed to gain insight into the performance of a powder lubricated thrust bearing. The results of simulations are compared to the published experimental results. Good agreement between the theory and experiment attests to the capability of the model and its potential for design of powder lubricated bearings.

Morphology of Voltage-Triggered Ordered Wrinkles of a Dielectric Elastomer Sheet

2017 ◽  
Vol 84 (11) ◽  
Author(s):  
Guoyong Mao ◽  
Lei Wu ◽  
Xueya Liang ◽  
Shaoxing Qu
Keyword(s):  
High Voltage ◽  
Optical Sensor ◽  
Material Science ◽  
Dielectric Elastomer ◽  
Theoretical Studies ◽  
Science And Engineering ◽  
Future Design ◽  
Experimental And Theoretical Studies ◽  
Theory And Experiment ◽  
Good Agreement

Wrinkles widely existing in sheets and membranes have attracted a lot of attention in the fields of material science and engineering applications. In this paper, we present a new method to generate ordered (striplike) and steady wrinkles of a constrained dielectric elastomer (DE) sheet coated with soft electrodes on both sides subjected to high voltage. When the voltage reaches a certain value, wrinkles will nucleate and grow. We conduct both experimental and theoretical studies to investigate the wavelength and amplitude of the wrinkle. The results show a good agreement between theory and experiment. Moreover, the amplitude and wavelength of ordered wrinkles can be tuned by varying the prestretch and geometry of the DE sheet, as well as the applying voltage. This study can help future design of DE transducers such as diffraction grating and optical sensor.

Direct observation of Ba+ velocity distributions in a drift tube using single‐frequency laser‐induced fluorescence

1987 ◽  
Vol 87 (9) ◽  
pp. 5578-5579 ◽  
Author(s):  
Rainer A. Dressler ◽  
Henning Meyer ◽  
Andrew O. Langford ◽  
Veronica M. Bierbaum ◽  
Stephen R. Leone
Keyword(s):  
Direct Observation ◽  
Drift Tube ◽  
Laser Induced Fluorescence ◽  
Single Frequency ◽  
Frequency Laser

Fiber-bulk hybrid Er:YAG laser with 1617 nm single frequency laser output

2012 ◽  
Vol 9 (9) ◽  
pp. 674-677 ◽  
Author(s):  
L N Zhu ◽  
C Q Gao ◽  
R Wang ◽  
Y Zheng ◽  
M W Gao
Keyword(s):  
Er:Yag Laser ◽  
Laser Output ◽  
Single Frequency ◽  
Frequency Laser

Determination of AlGaN/GaN HEMT Reliability Using Optical Pumping as a Characterization Method

2012 ◽  
Vol 1432 ◽  
Author(s):  
D. Cheney ◽  
R. Deist ◽  
B. Gila ◽  
F. Ren ◽  
P. Whiting ◽  
...  
Keyword(s):  
Band Gap ◽  
Optical Pumping ◽  
Drain Current ◽  
Stress Tests ◽  
Optically Pumped ◽  
Gan Hemt ◽  
Load Line ◽  
Gan Hemts ◽  
Dc Stress

ABSTRACTBy pumping AlGaN/GaN HEMTs with below band-gap light we observe changes in drain current that correspond to the trapping and detrapping of carriers within the band-gap. These changes in drain current are indicators of trap density, since the energy from a specific wavelength of light pumps traps whose activation energies are less than or equal to that of the light source.AlGaN/GaN HEMTs on SiC with dual submicron gates with widths of 125nm, 140nm, or 170nm, are DC-stressed under three different conditions along a load line: VGS=0, VDS=5 (on-state), VGS=-2, VDS=9.2 and, VGS=-6, VDS=25 (off-state). The stress tests are interrupted at 20% degradation and the optically pumped comparisons to the baseline are measured.This paper describes the optical pumping technique and results from experiments of AlGaN/GaN HEMTs under the three DC stress biases along a load line.

scholarly journals Design and Construction Optical Pumping System

2013 ◽  
Vol 10 (2) ◽  
pp. 462-471
Author(s):  
Baghdad Science Journal
Keyword(s):  
Current Density ◽  
Optical Pumping ◽  
Electrical Energy ◽  
Discharge Voltage ◽  
Flash Lamp ◽  
Damping Factor ◽  
Discharge Current Density ◽  
Pumping System ◽  
Impedance Parameters ◽  
Design And Construction

In this work the design and construction of optical pumping system was presented. The parameters of the pumping source to obtain discharge current density sufficient to shift the flash lamp spectrum towards uv portion of spectrum were measured.The current density was supplied to the flash lamp must be greater than 4000Amp./cm2 to obtain the spectral range wavelength lies between 0.2 and 0.35?m. The current density was obtained by a capacitor 50?F, at 7KV discharge voltage. The applied electrical energy to the flash lamp was more than 1200 J, and the current density was around 5000 Amp./cm2.The electrical parameters of the flash lamp were calculated. The impedance parameters(K0) from the voltage and the peak current pulse was measured in range equal to 57, while the damping factor(?) was 1.3. The energy of the flash lamp was around 75% from the input electrical energy. The external trigger circuit was limited the increase the applied voltage, which is responsible for the damping factor.

A 160 W single-frequency laser based on an active tapered double-clad fiber amplifier

2013 ◽  
Vol 10 (6) ◽  
pp. 065101 ◽  
Author(s):  
A I Trikshev ◽  
A S Kurkov ◽  
V B Tsvetkov ◽  
S A Filatova ◽  
J Kertulla ◽  
...  
Keyword(s):  
Fiber Amplifier ◽  
Single Frequency ◽  
Frequency Laser
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