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671.
Jiaguo Zhang Ioana Pintilie Eckhart Fretwurst Robert Klanner Hanno Perrey Joern Schwandt 《Journal of synchrotron radiation》2012,19(3):340-346
Imaging experiments at the European X‐ray Free Electron Laser (XFEL) require silicon pixel sensors with extraordinary performance specifications: doses of up to 1 GGy of 12 keV photons, up to 105 12 keV photons per 200 µm × 200 µm pixel arriving within less than 100 fs, and a time interval between XFEL pulses of 220 ns. To address these challenges, in particular the question of radiation damage, the properties of the SiO2 layer and of the Si–SiO2 interface, using MOS (metal‐oxide‐semiconductor) capacitors manufactured on high‐resistivity n‐type silicon irradiated to X‐ray doses between 10 kGy and 1 GGy, have been studied. Measurements of capacitance/conductance–voltage (C/G–V) at different frequencies, as well as of thermal dielectric relaxation current (TDRC), have been performed. The data can be described by a dose‐dependent oxide charge density and three dominant radiation‐induced interface states with Gaussian‐like energy distributions in the silicon band gap. It is found that the densities of the fixed oxide charges and of the three interface states increase up to dose values of approximately 10 MGy and then saturate or even decrease. The shapes and the frequency dependences of the C/G–V measurements can be quantitatively described by a simple model using the parameters extracted from the TDRC measurements. 相似文献
672.
Bogdan M. Diaconu Mihai Cruceru Adina Teodora Gheorghian Luminiţa Georgeta Popescu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(16):2100-2112
View factor – defined as fraction of total outgoing radiation from surface 1 intercepted by surface 2 – is a key concept in solving the radiative heat transfer in systems of surfaces. Analytical forms of the view factor have been developed by means of integration for many conventional systems of 2D and 3D surfaces in various spatial positions. However, little investigation has been carried out for situations in which there is no complete visibility between the surfaces involved in radiative exchange due to configuration of 3D surfaces or due to presence of interposing object that obstruct partially the mutual visibility.Radiative heat exchange was modeled in a finite length cylindrical annulus consisting of non-isothermal diffusely-emitting surfaces. The canonical definition of the view factor was extended by means of an analytical approach to both 3D and 2D surfaces with shading effects (incomplete mutual visibility) and numerical algorithms were developed in order to calculate view factors values and test view factor algebra rules. The system considered in this paper was an axysymmetric cylindrical annulus – frequently used in many heat transfer applications. View factor values for various surface elements were calculated by means of numerical integration. View factor algebra rules – summation and reciprocity – were verified. 相似文献
673.
Ion Chiţescu 《Rendiconti del Circolo Matematico di Palermo》2001,50(3):455-476
This paper is a natural continuation of the paper [2] by the same author.
We shall prove that several coincidence and rigidity phenomena which usually do not appear are possible only in case the underlying
measure space is trivial (i.e. is a finite union of atoms). Examples: coincidence of twoL
p
spaces, reflexivity ofL
1, Radon—Nikodym property ofL
∞, coincidence of Dunford, Pettis or Bochner integrability, coincidence of theL
p
space and of the weakL
p
space. 相似文献
674.
675.
Alexandra-Elisabeta Stamate Rodica Zvoianu Octavian Dumitru Pavel Ruxandra Birjega Andreea Matei Marius Dumitru Ioana Brezetean Mariana Osiac Ioan-Cezar Marcu 《Molecules (Basel, Switzerland)》2021,26(20)
Mechanical activation and mechanochemical reactions are the subjects of mechanochemistry, a special branch of chemistry studied intensively since the 19th century. Herein, we comparably describe two synthesis methods used to obtain the following layered double hydroxide doped with cerium, Mg3Al0.75Ce0.25(OH)8(CO3)0.5·2H2O: the mechanochemical route and the co-precipitation method, respectively. The influence of the preparation method on the physico-chemical properties as determined by multiple techniques such as XRD, SEM, EDS, XPS, DRIFT, RAMAN, DR-UV-VIS, basicity, acidity, real/bulk densities, and BET measurements was also analyzed. The obtained samples, abbreviated HTCe-PP (prepared by co-precipitation) and HTCe-MC (prepared by mechanochemical method), and their corresponding mixed oxides, Ce-PP (resulting from HTCe-PP) and Ce-MC (resulting from HTCe-MC), were used as base catalysts in the self-condensation reaction of cyclohexanone and two Claisen–Schmidt condensations, which involve the reaction between an aromatic aldehyde and a ketone, at different molar ratios to synthesize compounds with significant biologic activity from the flavonoid family, namely chalcone (1,3-diphenyl-2-propen-1-one) and flavone (2-phenyl-4H-1benzoxiran-4-one). The mechanochemical route was shown to have indisputable advantages over the co-precipitation method for both the catalytic activity of the solids and the costs. 相似文献
676.
Georgiana Ioana Potra Cicalu Petru Aurel Babes Horia Calniceanu Adelina Popa Gabriela Ciavoi Gilda Mihaela Iova Mariana Ganea Ioana Scrobot 《Molecules (Basel, Switzerland)》2021,26(22)
Periodontal disease and diabetes mellitus are two pathologies that are extremely widespread worldwide and share the feature of chronic inflammation. Carvacrol is a phenolic monoterpenoid, produced by a variety of herbs, the most well-known of which is Origanum vulgare. Magnolol is a traditional polyphenolic compound isolated from the stem bark of Magnolia officinalis, mainly used in Chinese medicine. The purpose of this paper is to review the therapeutic properties of these bioactive compounds, in the treatment of periodontitis and diabetes. Based on our search strategy we conducted a literature search in the PubMed and Google Scholar databases to identify studies. A total of one hundred eighty-four papers were included in the current review. The results show that carvacrol and magnolol have anti-inflammatory, antioxidant, antimicrobial, anti-osteoclastic, and anti-diabetic properties that benefit both pathologies. Knowledge of the multiple activities of carvacrol and magnolol can assist with the development of new treatment strategies, and the design of clinical animal and human trials will maximize the potential benefits of these extracts in subjects suffering from periodontitis or diabetes. 相似文献
677.
678.
Luminiţa Fritea Mihaela Tertiş Cecilia Cristea Robert Săndulescu 《Electroanalysis》2023,35(1):e202200014
Cyclodextrins and nanomaterials are widely used in the achievement of powerful platforms in supramolecular chemistry and nanotechnology. The relatively hydrophobic internal cavity of the CDs selectively retains molecules having the proper geometry, while the hydrophilic exterior allows CDs to improve the dispersibility and molecular recognition. The nanomaterials provide higher surface area, good conductivity, and electrocatalytic effect. The use of nanomaterials and CDs in electrochemical sensors’ design allows the development of a large variety of devices, explaining the increasing number of papers in the last years that are discussed in this review. 相似文献
679.
Leau Sorina Alexandra Lete Cecilia Marin Mariana del Campo Francisco Javier Diaconu Ioana Lupu Stelian 《Journal of Solid State Electrochemistry》2023,27(7):1755-1766
Journal of Solid State Electrochemistry - The development and analytical applications of electrochemical sensors based on antimony tin oxide (ATO)–Prussian blue (PB) screen-printed electrode... 相似文献