1,390 research outputs found

    Cystic meningioangiomatosis with enhancing mural nodule on MRI and no calcification on CT

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    The neuroradiological features of meningioangiomatosis (MA) are non-specific. We report a young man with sporadic MA. The plain computerized tomography (CT) demonstrated a deep located right cystic lesion without calcification. On magnetic resonance imaging, the cystic mass lesion was confirmed with a mural nodule with significant enhancement on contrast-enhanced images

    The Theory of Reasoned Action Applied to Green Smartphones: Moderating Effect of Government Subsidies

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    [[abstract]]Smartphones have become indispensable for human beings today. However, with mobile phone manufacturers updating existing models or launching new models every year, consumers tend to keep replacing their phones with the latest versions, resulting in an excessive waste of resources. These days, most governments worldwide emphasize energy conservation and carbon reduction. If pre-owned smartphones are refurbished or repaired, the excessive waste of resources can be reduced. Such recycling can positively enhance corporate image, while ensuring that consumer needs are met. Thus, to explore consumers’ willingness to purchase such “green” smartphones, this study uses the theory of reasoned action (TRA) to explore consumers’ purchase intentions and understand how brand equity, green marketing, as well as consumer’s green awareness and attitude influence this intention. This research also investigates the role of government subsidies as a moderator affecting consumers’ willingness to purchase green smartphones. The results indicate that, in general, consumers are willing to purchase green smartphones, the direct effect of brand equity on purchase intention is significant, and government subsidies have significant moderating effects. Therefore, it is recommended that the government cooperate with enterprises. The cooperation can be aimed at promoting green products as well as subsidizing consumers, to increase their willingness to purchase green smartphones.[[notice]]èŁœæ­ŁćźŒ

    Effective Dynamic Range in Measurements with Flash Analog-to-Digital Convertor

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    Flash Analog to Digital Convertor (FADC) is frequently used in nuclear and particle physics experiments, often as the major component in big multi-channel systems. The large data volume makes the optimization of operating parameters necessary. This article reports a study of a method to extend the dynamic range of an 8-bit FADC from the nominal 28\rm{2^8} value. By comparing the integrated pulse area with that of a reference profile, good energy reconstruction and event identification can be achieved on saturated events from CsI(Tl) crystal scintillators. The effective dynamic range can be extended by at least 4 more bits. The algorithm is generic and is expected to be applicable to other detector systems with FADC readout.Comment: 19 pages, 1 table, 10 figure

    A Study on the Sudden Death of Entanglement

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    The dynamics of entanglement and the phenomenon of entanglement sudden death (ESD) \cite{yu} are discussed in bipartite systems, measured by Wootters Concurrence. Our calculation shows that ESD appears whenever the system is open or closed and is dependent on the initial condition. The relation of the evolution of entanglement and energy transfer between the system and its surroundings is also studied.Comment: Comments and criticism are welcome. Accepted by Phys. Lett.

    Measurement of Ultra-Low Potassium Contaminations with Accelerator Mass Spectrometry

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    Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Among the radio-isotopes, \k40 is one of the most abundant and yet whose signatures are difficult to reject. Procedures were devised to measure trace potassium concentrations in the inorganic salt CsI as well as in organic liquid scintillator (LS) with Accelerator Mass Spectrometry (AMS), giving, respectively, the \k40-contamination levels of ∌10−10\sim 10^{-10} and ∌10−13\sim 10^{-13} g/g. Measurement flexibilities and sensitivities are improved over conventional methods. The projected limiting sensitivities if no excess of potassium signals had been observed over background are 8×10−138 \times 10^{-13} g/g and 3×10−173 \times 10^{-17} g/g for the CsI and LS, respectively. Studies of the LS samples indicate that the radioactive contaminations come mainly in the dye solutes, while the base solvents are orders of magnitude cleaner. The work demonstrate the possibilities of measuring naturally-occurring isotopes with the AMS techniques.Comment: 18 pages, 4 figures, 3 table

    Impact of highly basic solutions on sorption of Cs+ to subsurface sediments from the Hanford site, USA

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    The effect of caustic NaNO3 solutions on the sorption of 137Cs to a Hanford site micaceous subsurface sediment was investigated as a function of base exposure time (up to 168 d), temperature (10°C or 50°C), and NaOH concentration (0.1 mol/L to 3 mol/L). At 10°C and 0.1 M NaOH, the slow evolution of [Al]aq was in stark contrast to the rapid increase and subsequent loss of [Al]aq observed at 50°C (regardless of base concentration). Exposure to 0.1 M NaOH at 10°C for up to 168 d exhibited little if any measurable effect on sediment mineralogy, Cs+ sorption, or Cs+ selectivity; sorption was well described with a two-site ion exchange model modified to include enthalpy effects. At 50°C, dissolution of phyllosilicate minerals increased with [OH]. A zeolite (tetranatrolite; Na2Al2Si3O10·2H2O) precipitated in 0.1 M NaOH after about 7 days, while an unnamed mineral phase (Na14Al12Si13O51·6H2O) precipitated after 4 and 2 days of exposure to 1 M and 3 M NaOH solutions, respectively. Short-term (16 h) Cs+ sorption isotherms (10−9–10−2 mol/L) were measured on sediment after exposure to 0.1 M NaOH for 56, 112, and 168 days at 50°C. There was a trend toward slightly lower conditional equilibrium exchange constants (∆log NaCsKc ~ 0.25) over the entire range of surface coverage, and a slight loss of high affinity sites (15%) after 168 days of pretreatment with 0.1 M base solution. Cs+ sorption to sediment over longer times was also measured at 50°C in the presence of NaOH (0.1 M, 1 M, and 3MNaOH) at Cs+ concentrations selected to probe a range of adsorption densities. Model simulations of Cs+ sorption to the sediment in the presence of 0.1 M NaOH for 112 days slightly under-predicted sorption at the lower Cs+ adsorption densities. At the higher adsorption densities, model simulations under-predicted sorption by 57%. This under-prediction was surmised to be the result of tetranatrolite precipitation, and subsequent slow Na → Cs exchange. At higher OH concentrations, Cs+ sorption in the presence of base for 112 days was unexpectedly equal to, or greater than that expected for pristine sediment. The precipitation of secondary phases, coupled with the fairly unique mica distribution and quantity across all size-fractions in the Hanford sediment, appears to mitigate the impact of base dissolution on Cs+ sorption

    Impact of highly basic solutions on sorption of Cs+ to subsurface sediments from the Hanford site, USA

    Get PDF
    The effect of caustic NaNO3 solutions on the sorption of 137Cs to a Hanford site micaceous subsurface sediment was investigated as a function of base exposure time (up to 168 d), temperature (10°C or 50°C), and NaOH concentration (0.1 mol/L to 3 mol/L). At 10°C and 0.1 M NaOH, the slow evolution of [Al]aq was in stark contrast to the rapid increase and subsequent loss of [Al]aq observed at 50°C (regardless of base concentration). Exposure to 0.1 M NaOH at 10°C for up to 168 d exhibited little if any measurable effect on sediment mineralogy, Cs+ sorption, or Cs+ selectivity; sorption was well described with a two-site ion exchange model modified to include enthalpy effects. At 50°C, dissolution of phyllosilicate minerals increased with [OH]. A zeolite (tetranatrolite; Na2Al2Si3O10·2H2O) precipitated in 0.1 M NaOH after about 7 days, while an unnamed mineral phase (Na14Al12Si13O51·6H2O) precipitated after 4 and 2 days of exposure to 1 M and 3 M NaOH solutions, respectively. Short-term (16 h) Cs+ sorption isotherms (10−9–10−2 mol/L) were measured on sediment after exposure to 0.1 M NaOH for 56, 112, and 168 days at 50°C. There was a trend toward slightly lower conditional equilibrium exchange constants (∆log NaCsKc ~ 0.25) over the entire range of surface coverage, and a slight loss of high affinity sites (15%) after 168 days of pretreatment with 0.1 M base solution. Cs+ sorption to sediment over longer times was also measured at 50°C in the presence of NaOH (0.1 M, 1 M, and 3MNaOH) at Cs+ concentrations selected to probe a range of adsorption densities. Model simulations of Cs+ sorption to the sediment in the presence of 0.1 M NaOH for 112 days slightly under-predicted sorption at the lower Cs+ adsorption densities. At the higher adsorption densities, model simulations under-predicted sorption by 57%. This under-prediction was surmised to be the result of tetranatrolite precipitation, and subsequent slow Na → Cs exchange. At higher OH concentrations, Cs+ sorption in the presence of base for 112 days was unexpectedly equal to, or greater than that expected for pristine sediment. The precipitation of secondary phases, coupled with the fairly unique mica distribution and quantity across all size-fractions in the Hanford sediment, appears to mitigate the impact of base dissolution on Cs+ sorption

    Theoretical study of the two-proton halo candidate 17^{17}Ne including contributions from resonant continuum and pairing correlations

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    With the relativistic Coulomb wave function boundary condition, the energies, widths and wave functions of the single proton resonant orbitals for 17^{17}Ne are studied by the analytical continuation of the coupling constant (ACCC) approach within the framework of the relativistic mean field (RMF) theory. Pairing correlations and contributions from the single-particle resonant orbitals in the continuum are taken into consideration by the resonant Bardeen-Cooper-Schrieffer (BCS) approach, in which constant pairing strength is used. It can be seen that the fully self-consistent calculations with NL3 and NLSH effective interactions mostly agree with the latest experimental measurements, such as binding energies, matter radii, charge radii and densities. The energy of π\pi2s1/2_{1/2} orbital is slightly higher than that of π1d5/2\pi1d_{5/2} orbital, and the occupation probability of the (π(\pi2s1/2)2_{1/2})^2 orbital is about 20%, which are in accordance with the shell model calculation and three-body model estimation

    Pulse Shape Discrimination Techniques in Scintillating CsI(Tl) Crystals

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    There are recent interests with CsI(Tl) scintillating crystals for Dark Matter experiments. The key merit is the capability to differentiate nuclear recoil (nr) signatures from the background ÎČ/Îł\beta / \gamma-events due to ambient radioactivity on the basis of their different pulse shapes. One of the major experimental challenges is to perform such pulse shape analysis in the statistics-limited domain where the light output is close to the detection threshold. Using data derived from measurements with low energy Îł\gamma's and nuclear recoils due to neutron elastic scatterings, it was verified that the pulse shapes between ÎČ/Îł\beta / \gamma-events are different. Several methods of pulse shape discrimination are studied, and their relative merits are compared. Full digitization of the pulse shapes is crucial to achieve good discrimination. Advanced software techniques with mean time, neural network and likelihood ratios give rise to satisfactory performance, and are superior to the conventional Double Charge method commonly applied at higher energies. Pulse shape discrimination becomes effective starting at a light yield of about 20 photo-electrons. This corresponds to a detection threshold of about 5 keV electron-equivalence energy, or 40−-50 keV recoil kinetic energy, in realistic experiments.Comment: 20 pages, 7 figure
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