1,268 research outputs found

    Similarity and contrasts between thermodynamic properties at the critical point of liquid alkali metals and of electron-hole droplets

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    The recent experimental study by means of time-resolved luminescence measurements of an electron-hole liquid (EHL) in diamond by Shimano et al. [Phys. Rev. Lett. 88 (2002) 057404] prompts us to compare and contrast critical temperature T_c and critical density n_c relations in liquid alkali metals with those in electron-hole liquids. The conclusion drawn is that these systems have similarities with regard to critical properties. In both cases the critical temperature is related to the cube root of the critical density. The existence of this relation is traced to Coulomb interactions and to systematic trends in the dielectric constant of the electron-hole systems. Finally a brief comparison between the alkalis and EHLs of the critical values for the compressibility ratio Z_c is also given

    Fabrication of advanced ceramic tritium breeders

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    AstroPix: investigating the potential of silicon pixel sensors in the future of gamma-ray astrophysics

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    This paper details preliminary photon measurements with the monolithic silicon detector ATLASPix, a pixel detector built and optimized for the CERN experiment ATLAS. The goal of this paper is to determine the promise of pixelated silicon in future space-based gamma-ray experiments. With this goal in mind, radioactive photon sources were used to determine the energy resolution and detector response of ATLASPix; these are novel measurements for ATLASPix, a detector built for a ground-based particle accelerator. As part of this project a new iteration of monolithic Si pixels, named AstroPix, have been created based on ATLASPix, and the eventual goal is to further optimize AstroPix for gamma-ray detection by constructing a prototype Compton telescope.The energy resolution of both the digital and analog output of ATLASPix is the focus of this paper, as it is a critical metric for Compton telescopes. It was found that with the analog output of the detector, the energyresolution of a single pixel was 7.69 +/- 0.13% at 5.89 keV and 7.27 +/- 1.18% at 30.1 keV, which exceeds the conservative baseline requirements of 10% resolution at 60 keV and is an encouraging start to an optimistic goal of<2% resolution at 60 keV. The digital output of the entire detector consistently yielded energy resolutions that exceeded 100% for different sources. The analog output of the monolithic silicon pixels indicates that thisis a promising technology for future gamma-ray missions, while the analysis of the digital output points to the need for a redesign of future photon-sensitive monolithic silicon pixel detectors

    Transceiver ASIC in HVCMOS Technology for 3D Ultrasound Computer Tomography

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    Abstract3D Ultrasound Computer Tomography (3D USCT) is an imaging method for the early de-tection of breast cancer. It provides three-dimensional multimodal images of the breast. Thenew 3D USCT device developed currently at Karlsruhe Institute of Technology containsmore than two thousand ultrasound transducers placed in a water-filled aperture where thepatient submerges one breast. The ultrasound transducers are grouped as transducer arraysystems (TAS) of 18 receiver (RX) and transmitter (TX) elements. The transducer front-end electronics contain high-voltage (HV) and low-voltage (LV) amplifiers and switcheswhich are implemented as an application-specific integrated circuit (ASIC). This contribu-tion presents a patented mixed signal, multichannel, transceiver ASIC developed in a com-mercial 350 nm high-voltage CMOS (HV-CMOS) process. The HV-CMOS process provideslow-voltage and high-voltage transistors that can be combined on the same substrate. TheHV transistors can sustain voltages up to 120 V

    Developing the future of gamma-ray astrophysics with monolithic silicon pixels

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    This paper explores the potential of AstroPix, a project to develop Complementary Metal Oxide Semiconductor (CMOS) pixels for the next generation of space-based high-energy astrophysics experiments. Multimessenger astrophysics is a rapidly developing field whose upcoming missions need support from new detector technology such as AstroPix. ATLASPix, a monolithic silicon detector optimized for the ATLAS particle detector at CERN, is the beginning of the larger AstroPix project. Energy resolution is a driving parameter in the reconstruction of gamma-ray events, and therefore the characterization of ATLASPix energy resolution is the focus of this paper. The intrinsic energy resolution of the detector exceeded our baseline requirements of <10% at 60 keV. The digital output of ATLASPix results in energy resolutions insufficient to advance gamma-ray astronomy. However, the results from the intrinsic energy resolution indicate the digital capability of the detector can be redesigned, and the next generation of pixels for the larger AstroPix project have already been constructed. Iterations of AstroPix-type pixels are an exciting new technology candidate to support new space-based missions

    Antibacterial nanocomposites based on Ag NPs and HMDSO deposited by atmospheric pressure plasma

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    The development of new multifunctional coatings with antimicrobial properties has a special interest in several applications for pharmaceutical and medical products. This work reports on the deposition of antimicrobial coatings based on silver nanoparticles (Ag NPs) embedded in an organosilicon film onto woven and nonwoven textiles. The Ag nanoparticles admixed with hexamethyldisiloxane (HMDSO) vapours are introduced by means of an atomizer system in the remote discharge of an atmospheric pressure plasma source operating in argon. The chemical properties and the surface morphology of the coatings with antimicrobial potential are discussed.This work was performed within the M-ERA-NET project PlasmaTex, contract 31/2016/ UEFISCDI. The financial support from the Ministry of Research and Innovation under the Nucleus contract 4N/2016 is gratefully acknowledged.info:eu-repo/semantics/publishedVersio

    A phase II study of raltitrexed and gemcitabine in patients with advanced pancreatic carcinoma

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    Advanced adenocarcinoma of the pancreas has a very poor prognosis. The aim of this study was to assess the efficacy and tolerability of a combination of the chemotherapeutic agents gemcitabine and raltitrexed. Chemonaïve patients with advanced adenocarcinoma of the pancreas were treated with a combination of raltitrexed (3.5 mg m−2 on day 1 of a 21-day treatment cycle) and gemcitabine (800 mg m−2 intravenously (i.v.) on days 1 and 8 of a 21-day cycle). Between April 2000 and February 2003, 27 patients were enrolled onto the study. The mean duration of treatment was 11 weeks. Four of 27 patients experienced at least one episode of grade 3 or 4 neutropenia. One patient with grade 4 neutropenia died due to sepsis. Four of 27 patients experienced grade 4 diarrhoea. There was one partial remission (4%) and 12 patients experienced disease stabilisation (44%). The 6-month and 1-year survival rates were 37 and 11%, respectively. Symptomatic benefit occurred in seven (26%) patients. We conclude that a combination of raltitrexed and gemcitabine, using the schedule and doses in this study, cannot be recommended for patients with advanced pancreatic cancer
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