198 research outputs found

    Exact results for a charged, harmonically trapped quantum gas at arbitrary temperature and magnetic field strength

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    An analytical expression for the first-order density matrix of a charged, two-dimensional, harmonically confined quantum gas, in the presence of a constant magnetic field is derived. In contrast to previous results available in the literature, our expressions are exact for any temperature and magnetic field strength. We also present a novel factorization of the Bloch density matrix in the form of a simple product with a clean separation of the zero-field and field-dependent parts. This factorization provides an alternative way of analytically investigating the effects of the magnetic field on the system, and also permits the extension of our analysis to other dimensions, and/or anisotropic confinement.Comment: To appear in Phys. Rev.

    Solution-processed nickel tetrabenzoporphyrin thin-film transistors

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    We describe nickel tetrabenzoporphyrin (NiTBP) as a solution-processible organic semiconductor. Whereas porphyrins in an unmodified state are typically planar and insoluble, a precursor synthetic route (NiCP) was used to deposit thin films via solution. Amorphous, insulating thin films of NiCP were deposited, and thermally converted to polycrystalline, semiconducting NiTBP. Films were studied using optical absorption and microscopy, atomic force microscopy, and x-ray diffraction. Highly concentrated NiCP was shown to form large, needle-shaped crystals drop-cast from solution. NiTBP thin-film field-effect transistors fabricated from spun-cast films demonstrated charge-carrier field-effect mobilities on the order of 0.1 and 0.2 cm2/V s0.2cm2∕Vs and accumulation threshold voltages of −19−19 and −13−13, in the linear and saturation regimes, respectively.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87777/2/034502_1.pd

    Turbine Powered Simulator Calibration and Testing for Hybrid Wing Body Powered Airframe Integration

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    Propulsion airframe integration testing on a 5.75% scale hybrid wing body model us- ing turbine powered simulators was completed at the National Full-Scale Aerodynamics Complex 40- by 80-foot test section. Four rear control surface con gurations including a no control surface de ection con guration were tested with the turbine powered simulator units to investigate how the jet exhaust in uenced the control surface performance as re- lated to the resultant forces and moments on the model. Compared to ow-through nacelle testing on the same hybrid wing body model, the control surface e ectiveness was found to increase with the turbine powered simulator units operating. This was true for pitching moment, lift, and drag although pitching moment was the parameter of greatest interest for this project. With the turbine powered simulator units operating, the model pitching moment was seen to increase when compared to the ow-through nacelle con guration indicating that the center elevon and vertical tail control authority increased with the jet exhaust from the turbine powered simulator units

    Comparison of Space Launch System Aerodynamic Surface Pressure Measurements from Experimental Testing and CFD

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    A comparison of surface pressure coefficient measurements obtained using pressure-sensitive paint (PSP) measurements with predictions from the computational fluid dynamics (CFD) code FUN3D is presented for the NASA SLS Block 1B crew vehicle. Overall, the flow features over the SLS configuration were captured by both the PSP data and CFD data at freestream Mach numbers (M(sub )) of 0.8 and 1.3. Overall, the flow features over the SLS are captured by the PSP data but the intensities of large pressure gradients are less intense than what was predicted by the CFD data. Several examples of this observation are given including the flow interaction at the booster nose cone edge, core body, and forward booster attachment hardware at M(sub ) = 0.8

    Outcomes of MYC-associated lymphomas after R-CHOP with and without consolidative autologous stem cell transplant: subset analysis of randomized trial intergroup SWOG S9704

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    Double hit lymphoma (DHL) and double protein-expressing (MYC and BCL2) lymphomas (DPL) fare poorly with R-CHOP; consolidative autologous stem cell transplant (ASCT) may improve outcomes. S9704, a phase III randomized study of CHOP +/−R with or without ASCT allows evaluation of intensive consolidation. Immunohistochemical analysis identified 27 of 198 patients (13.6%) with MYC IHC overexpression and 20 (74%) harboring concurrent BCL2 overexpression. Four had DHL and 16 had DPL only. With median follow-up 127 months, there is a trend favoring outcomes after consolidative ASCT in DPL and MYC protein overexpressing patients, whereas all DHL patients have died irrespective of ASCT

    Inhaled Nanoparticles Accumulate at Sites of Vascular Disease

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    The development of engineered nanomaterials is growing exponentially, despite concerns over their potential similarities to environmental nanoparticles that are associated with significant cardiorespiratory morbidity and mortality. The mechanisms through which inhalation of nanoparticles could trigger acute cardiovascular events are emerging, but a fundamental unanswered question remains: Do inhaled nanoparticles translocate from the lung in man and directly contribute to the pathogenesis of cardiovascular disease? In complementary clinical and experimental studies, we used gold nanoparticles to evaluate particle translocation, permitting detection by high-resolution inductively coupled mass spectrometry and Raman microscopy. Healthy volunteers were exposed to nanoparticles by acute inhalation, followed by repeated sampling of blood and urine. Gold was detected in the blood and urine within 15 min to 24 h after exposure, and was still present 3 months after exposure. Levels were greater following inhalation of 5 nm (primary diameter) particles compared to 30 nm particles. Studies in mice demonstrated the accumulation in the blood and liver following pulmonary exposure to a broader size range of gold nanoparticles (2-200 nm primary diameter), with translocation markedly greater for particles <10 nm diameter. Gold nanoparticles preferentially accumulated in inflammation-rich vascular lesions of fat-fed apolipoproteinE-deficient mice. Furthermore, following inhalation, gold particles could be detected in surgical specimens of carotid artery disease from patients at risk of stroke. Translocation of inhaled nanoparticles into the systemic circulation and accumulation at sites of vascular inflammation provides a direct mechanism that can explain the link between environmental nanoparticles and cardiovascular disease and has major implications for risk management in the use of engineered nanomaterials

    Experimental Evaluation of Inlet Distortion on an Ejector Powered Hybrid Wing Body at Take-off and Landing Conditions

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    As part of the NASA Environmentally Responsible Aircraft project, an ultra high bypass ratio engine integration on a hybrid wing body demonstration was planned. The goal was to include engine and airframe integration concepts that reduced fuel consumption by at least 50% while still reducing noise 42 db cumulative on the ground. Since the engines would be mounted on the upper surface of the aft body of the aircraft, the inlets may be susceptible to vortex ingestion from the wing leading edge at high angles of attack and sideslip, and separated wing/body flow. Consequently, experimental and computational studies were conducted to collect flow surveys useful for characterizing engine operability. The wind tunnel tests were conducted at two NASA facilities, the 14- by 22-foot at NASA Langley and the 40- by 80-foot at NASA Ames Research Center. The test results included in this paper show that the distortion and pressure recovery levels were acceptable for engine operability. The CFD studies conducted to compare to experimental data showed excellent agreement for the angle of attacks examined, although failed to match the low speed experimental data at high sideslip angles
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