[en] From the theory of acoustic waves generation by turbulent flow, it has been demonstrated by a numerical simulation that it is possible to identify the acoustic source associated with a circuit singularity in the presence of other perturbing sources belonging to the same circuit. The experiment carried out on a butterfly valve for flows with a Mach number below 10^-2 has allowed the prediction of the source and in the mean time we have get the transfer matrix of that part of the circuit containing the singularity. The method presented here is sufficiently general to allow the analysis of every component of a circuit as long as the linear hypothesis is still valid for the flow under consideration. (author)

[en] In the L3 experiment at CERN the momenta of high energetic muons created in e⁺e^- collisions in LEP (''Large Electron Positron Collider'') are measured with high precision. This facilitates the detection of yet unknown neutral particles decaying into muon pairs, which may exist in the mass range accessible at LEP. The high muon momentum resolution will also allow a precise measurement of the mass of the Higgs particle - if it shows up at LEP. The measuring device is a very precise magnetic spectrometer. 176 huge multiwire drift chambers serve as detectors. They enclose in a homogeneous magnetic field of 0.5 T a volume of about 1000 m³. In order to achieve for muons from Z^o decay (P_μ = 45 GeV) momentum resolution of 2.4%, novel solution had to be chosen for the design and construction of the spectrometer. Muons travel in the L3 spectrometer a distance of about 3 m. Along this trajectory the relative positions of the detector wires must be known within ± 30 μm. A novel alignment system forms the basis for the solution of this requirement. Together with other vital operational parameters of the spectrometer the alignment system is remotely monitored in order to keep constant the initially achieved high momentum resolution over a long period of time. The monitor system receives input data from many different sensors situated in the spectrometer. Several integrated online computers networked together with host computers acquire and evaluate the data. This thesis gives a detailed description of both the alignment system and the monitor system of the L3 Muon Spectrometer. The momentum resolution achieved in the first LEP runs is given and first physics results are presented. (author) figs., tabs., refs

[en] Objective: To study the interrelation between the degree of infection and changes in cellular factors in pediatrics mycoplasma pneumonia patients. Methods: 91 cases of pediatric mycoplasma pneumonia were divided into a serious group and a lighter group according to the serum IgM levels. The fast serum levels of tumor necrosis factor-a (TNF-α) and interleukin-6 (IL-6) were determined with ratio-immunoassay (RIA) in those patients as well as 35 controls. Results: The levels of serum TNF-α and IL-6 in both groups of patients were significantly higher than those in the controls (P < 0.01). The levels in the serious group were also significantly higher than those in the lighter group (P < 0.05). The data in patient groups were analysed with linear correlation. The correlative coefficient of TNF-α was r = 0.49 and that of IL-6 was r = 0.95, Suggesting positive correlation with the seriousness of infection. Conclusion: The cellular factors TNF-α and IL-6 might participate in the whole process of mycoplasma infection and their serum levels were positively correlated with the seriousness of the disease

[en] Incoloy 800H is a potential core component material for high temperature gas-cooled reactors (HTGRs), with expected operating temperatures above 750 °C. However, creep rupture resistance of conventional Incoloy 800H welds is significantly degraded when the environmental temperature is higher than 475 °C. The objective of this work is to explore the weldability of Incoloy 800H using the gas tungsten arc welding (GTAW) technique with Inconel 625 filler material. Welding microstructure was characterized using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Micro-hardness and high temperature tensile properties (conducted at 760 °C) of Incoloy 800H welds were measured. Incoloy 800H welded with Inconel 625 filler material showed superior high temperature tensile strength compared to the unwelded base metal (BM). The weld failure occurred outside the welding zones. The Incoloy 800H welds showed more than a 50% increase in yield strength compared to the BM. In contrast, the ultimate tensile strength is minimally affected by welding. Microstructural characterization shows that the welding process induced the diffusion of alloying elements across fusion boundaries and the formation of a large number of nano-precipitates in the heat-affected zone and fusion zone. As a result, the high temperature mechanical properties of Incoloy 800H were enhanced due to the effects of solid solution strengthening and precipitation strengthening. (author)

[en] Incoloy 800H is a potential core component material for high temperature gas-cooled reactors (HTGRs). However, the mechanical properties of conventional Incoloy 800H welds could be significantly degraded when the environmental temperature is higher than 475 °C. The objective of this work is to understand the strengthening and plastic deformation mechanisms of Incoloy 800H gas tungsten arc welds with different filler materials, including Haynes 230 and Inconel 625 filler materials, by characterizing and analyzing the microstructural and phase evolution. Optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to identify the constituent phases in the welds at fusion zone (FZ) and heat-affected zone (HAZ). Precipitation of secondary phase particles of Ti(C,N) and other compounds from the solid solution-strengthened austenitic g-phase matrix were confirmed in the fusion zone (FZ) and heat-affected zone (HAZ). Solid solution strengthening is the dominant effect for the mechanical properties of Incoloy 800H and its welds with filler materials comprised of Haynes 230 and Inconel 625. Welding-induced nano-precipitates in the HAZ and FZ enhance the high-temperature strength of Incoloy 800H welds. (author)

[en] Graphical abstract: - Highlights: • We systematically investigated the photocatalytic characteristics of Ag₃PO₄. • Ag₃PO₄ cannot photodegrade volatile organic compounds such as benzene, acetone. • Ag₃PO₄ is efficient for dye photodegradation rather than dye photomineralization. • Ag₃PO₄ itself is photostable but quickly deactivate during dye photodegradation. - Abstract: Ag₃PO₄ photocatalyst was prepared by precipitation method and characterized by SEM, XRD and diffusive reflectance UV–vis (DRUV–vis) absorption spectra. The gas-phase photodegradation of volatile organic compounds (VOCs) such as benzene and acetone, and the liquid-phase photodegradation of the cationic and anionic dyes on Ag₃PO₄ were systematically investigated. Both benzene and acetone could not be photodegraded on the Ag₃PO₄ photocatalyst under the visible irradiation. The Ag₃PO₄ photocatalyst is efficient for the photodegradation of the aqueous dye solutions, but could not completely photomineralize the dyes to CO₂ and H₂O. The reason is discussed by comparing the oxidation potential of organic pollutants and the potential of photogenerated holes in Ag₃PO₄, and measuring the absorption of organic pollutants on Ag₃PO₄. The photostability of the Ag₃PO₄ photocatalyst for the photo-degradation of the dyes was tested. The Ag₃PO₄ photocatalyst itself is photostable in the absence of the scavenger of the photogenerated holes, but is photocatalytically instable in the liquid-phase photodegradation of dyes due to the photoreduction of Ag⁺ in Ag₃PO₄ to Ag

No abstract available

[en] Highlights: • The design and operation of a tri-generation system for a station was investigated. • The tri-generation cycle was analyzed from the view points of both first and second laws of thermodynamics. • The calculated maximum comprehensive energy efficiency was 94.94% in the winter, and 84.33% in the summer. • The calculated maximum exergy efficiency was 38.01% in the winter, and 36.01% in the summer. • The recovered year of the increased investment was 5.47 year. - Abstract: Tri-generation usually refers to the simultaneous production of power, heating and cooling. Tri-generation can be regarded as a high-efficiency technology, provided that a large proportion of the energy rejected by the prime mover is used. In this paper, the design and operation of a tri-generation system for a railway station was investigated. The system is composed of the internal combustion engine (ICE), absorption heat pump (AHP), heat exchanger (HE), and other facilities. The system was built and operated in 2011, and the energy efficiency level was analyzed. The results indicated that the calculated maximum comprehensive energy efficiency (CEE) was 94.94% in the winter and 84.33% in the summer; with the calculated maximum exergy efficiency is 38.01% in the winter and 36.01% in the summer. The primary energy saving (PES) of the system was 32.2% in the winter and 4.9% in the summer. The system could therefore be regarded as high efficiency tri-generation. The recovered year of the increased investment was 5.47 year compared with the reference system. These results could serve as a reference for designing or evaluating tri-generation systems

[en] The studies show that for dichromate solution/Ag⁺ dosimeters in the 10-40 kGy range, the response to dose is in good linearity, and the effects of dose rate and temperature during irradiation on absorption dose response could be negligible. Furthermore, the dosimeter solutions have good storage stability before and after irradiation. So long as the preparation of dosimeters and the measuring procedure are well controlled, the precision of the system can reach to about 1%, and total uncertainty to ±3.5%. The system can be used as transfer standard dosimeters for high-dose measurement

[en] We report on the electrical and thermal transport properties of the Sn_1_−_xPb_xBi_2Te_4 series and we discuss the potential of these materials for thermoelectric conversion applications. From the evolution of the XRD patterns, we can confidently conclude that a complete solid solution exists between SnBi_2Te_4 and PbBi_2Te_4, with no miscibility gap. A crossover from p-type conduction in Sn-rich samples to n-type conduction in Pb-rich ones has been observed, with a transition between x=0.3 and 0.4. A concomitant increase of the electrical resistivity and of the Seebeck coefficient has been observed in the solid solution, which leads to almost constant values of the thermoelectric power factor. Moreover, the thermal conductivity is slightly reduced in the solid solution. The best figure of merit ZT values at room temperature have been observed for p-type Sn_0_._8Pb_0_._2Bi_2Te_4 with ZT=0.25 and for n-type Sn_0_._3Pb_0_._7Bi_2Te_4 with ZT=0.15. - Graphical abstract: Seebeck coefficient in (Pb/Sn)Bi_2Te_4 solid solution. - Highlights: • A complete solid solution exists between PbBi_2Te_4 and SnBi_2Te_4_. • A crossover between p-type and n-type is observed for 0.3< Pb fraction <0.4. • The lattice thermal conductivity is hardly reduced in the solid solution