9,780 research outputs found
Lattice constant variation and complex formation in zincblende Gallium Manganese Arsenide
We perform high resolution X-ray diffraction on GaMnAs mixed crystals as well
as on GaMnAs/GaAs and GaAs/MnAs superlattices for samples grown by low
temperature molecular beam epitaxy under different growth conditions. Although
all samples are of high crystalline quality and show narrow rocking curve
widths and pronounced finite thickness fringes, the lattice constant variation
with increasing manganese concentration depends strongly on the growth
conditions: For samples grown at substrate temperatures of 220 and 270 degrees
C the extrapolated relaxed lattice constant of Zincblende MnAs is 0.590 nm and
0.598 nm respectively. This is in contrast to low temperature GaAs, for which
the lattice constant decreases with increasing substrate temperature.Comment: pdf onl
Method of Attaching Strain Gauges to Various Materials
A method is provided to bond strain gauges to various materials. First, a tape with an adhesive backing is placed across the inside of the fixture frame. The strain gauge is flatly placed against the adhesive backing and coated with a thin, uniform layer of adhesive. The tape is then removed from the fixture frame and placed, strain gauge side down, on the material to be tested. If the material is a high reluctance material, the induction heating source is placed on the tape. If the material is a low reluctance material, a plate with a ferric side and a rubber side is placed, ferric side down, onto the tape. The induction heating source is then placed upon the rubber side. If the material is an insulator material, a ferric plate is placed on the tape. The induction heating source is then placed on the ferric plate. The inductive heating source then generates frequenty from 60 to 70 kilocycles to inductively heat either low reluctance material, ferric side, of ferric plate and provides incidental pressure of approximately five pounds per square inch to the tape for two minutes, thoroughly curing the adhesive. The induction heating source, and, if necessary, the plate or ferric plate, are then removed from the tape after one minute. The tape is then removed from the bonded strain gauge
Lumbar Facet Joint Pain: Pathology and Treatment Via Facet Joint Injection and Medial Branch Neurology
Clinic spinal pain or back pain as it is sometimes referred is a serious medical problem with se1ious financial and social consequences (Manchikanti, 1999). Back and neck pain are the most common cause of chronic pain and disability (Raso, 2010). Certified Registered Nurse Anesthetists are advanced practitioners with the ability to treat lower back pain using advanced interventional procedures; however, they currently are not pardoning these interventions in North Dakota. A comprehensive literature review was utilized to gather current data and group trends in the treatment of lumbar facet joint pain. History and physicals, while helpful, do not accurately diagnose lumbar facet joint pain. Advanced imaging using x-ray, CT, and MRI also does not correctly diagnose lumbar facet joint mediated back pain. Repeated, controlled diagnostic nerve blocks are the only proven method of diagnosing lumbar back pain of facet origin. Four treatment modalities: intra-articular injection, lumbar pen-articular injection, medial branch block, and medial branch neurotomy are described in this paper. Controlled diagnostic blocks are the best means to diagnose facet mediated lower back pain. Medial branch block and neurotomy provide the highest percentage forelife for the greatest period of time out of the interventions explored. Presentation of these findings to Certified Registered Nurse Anesthetists and Student Registered Nurse Anesthetists will increase their knowledge base and raise awareness of diagnostic and treatment options for lumbar facet joint pain
Quicksort with unreliable comparisons: a probabilistic analysis
We provide a probabilistic analysis of the output of Quicksort when
comparisons can err.Comment: 29 pages, 3 figure
Idiopathic orthostatic hypotension: Recent data (eleven cases) and review of the literature
Eight cases of Shy-Drager syndrome and three of Bradbury-Eggleston idiopathic orthostatic hypotension were examined. In all cases, examination of circulatory reflexes showed major dysfunction of the sympathetic vasoconstrictor system. Anomalies in the vagal cardiomoderator system were less constant. Normal urinary elimination of catecholamines was recorded daily. Characteristically, no elevation of blood or urine norepinephrine levels were found in orthostatism. Insulin hypoglycemia normally raised urinary adrenalin elimination in three of ten patients. Plasma dopa-beta-hydroxylase activity was normal. Renin-angiotensin-aldosterone system showed variable activity at basal state but usually rose during orthostatism. On the average, very low homovanillic acid levels were found in cerebrospinal fluid before and after probenecid; hydroxyindolacetic acid was normal. Cerebral autoregulation had deteriorated in two of four cases. Physiopathologically the two clinical types are indistinguishable with or without central neurological signs
Electro-optic routing of photons from single quantum dots in photonic integrated circuits
Recent breakthroughs in solid-state photonic quantum technologies enable
generating and detecting single photons with near-unity efficiency as required
for a range of photonic quantum technologies. The lack of methods to
simultaneously generate and control photons within the same chip, however, has
formed a main obstacle to achieving efficient multi-qubit gates and to harness
the advantages of chip-scale quantum photonics. Here we propose and demonstrate
an integrated voltage-controlled phase shifter based on the electro-optic
effect in suspended photonic waveguides with embedded quantum emitters. The
phase control allows building a compact Mach-Zehnder interferometer with two
orthogonal arms, taking advantage of the anisotropic electro-optic response in
gallium arsenide. Photons emitted by single self-assembled quantum dots can be
actively routed into the two outputs of the interferometer. These results,
together with the observed sub-microsecond response time, constitute a
significant step towards chip-scale single-photon-source de-multiplexing,
fiber-loop boson sampling, and linear optical quantum computing.Comment: 7 pages, 4 figues + supplementary informatio
Experimental determination of the degree of quantum polarisation of continuous variable states
We demonstrate excitation-manifold resolved polarisation characterisation of
continuous-variable (CV) quantum states. In contrast to traditional
characterisation of polarisation that is based on the Stokes parameters, we
experimentally determine the Stokes vector of each excitation manifold
separately. Only for states with a given photon number does the methods
coincide. For states with an indeterminate photon number, for example Gaussian
states, the employed method gives a richer and more accurate description. We
apply the method both in theory and in experiment to some common states to
demonstrate its advantages.Comment: 5 page
Initial results of a flight investigation of the wing and tail loads on an airplane equipped with a vane-controlled gust-alleviation system
Results are given of an analysis of wing and horizontal-tail spar strains measured on a twin-engine light transport airplane which was modified for the installation of a control system to alleviate airplane motions in turbulent air and thus improve passenger comfort. From a sample of the measurements obtained in flight through clear-air turbulence, normal acceleration at the airplane center of gravity was reduced 43 percent, wing main-spar bending strains were reduced, and wing-spar shear strains were increased. Horizontal-tail shear and bending strains were increased. Measurements of aerodynamic loads obtained in a pull-up with the gust-alleviation system in operation are also presented
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