1,222 research outputs found

    Discussion on the Water-Saving Technology of the Green Community

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    As an architectural concept, green building surveys the impact of building activities to the environment from the perspective of building lifecycle, and implements the sustainable development of the building, of which water resource is a very important factor. Combined with evaluation criteria of the green building in China, this paper analyzes the main existing problems of water conservation in Chinese residential communities and proposes the development orientation of the green community in our country in the future, compared with the relative technical measures home and abroad from the following four aspects: water-saving products, grey water treatment and reuse, rainwater and reclaimed water utilization

    Rotational Spectroscopy Meets Quantum Chemistry for Analyzing Substituent Effects on Non-Covalent Interactions: The Case of the Trifluoroacetophenone-Water Complex

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    The most stable isomer of the 1:1 complex formed by 2,2,2-trifluoroacetophenone and water has been characterized by combining rotational spectroscopy in supersonic expansion and state-of-the-art quantum-chemical computations. In the observed isomer, water plays the double role of proton donor and acceptor, thus forming a seven-membered ring with 2,2,2-trifluoroacetophenone. Accurate intermolecular parameters featuring one classical O-H···O hydrogen bond and one weak C-H···O hydrogen bond have been determined by means of a semi-experimental approach for equilibrium structure. Furthermore, insights on the nature of the established non-covalent interactions have been unveiled by means of different bond analyses. The comparison with the analogous complex formed by acetophenone with water points out the remarkable role played by fluorine atoms in tuning non-covalent interactions

    Nonlinear Decoherence in Quantum State Preparation of a Trapped Ion

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    We present a nonlinear decoherence model which models decoherence effect caused by various decohereing sources in a quantum system through a nonlinear coupling between the system and its environment, and apply it to investigating decoherence in nonclassical motional states of a single trapped ion. We obtain an exactly analytic solution of the model and find very good agreement with experimental results for the population decay rate of a single trapped ion observed in the NIST experiments by Meekhof and coworkers (D. M. Meekhof, {\it et al.}, Phys. Rev. Lett. {\bf 76}, 1796 (1996)).Comment: 5 pages, Revte

    Hydrogen adsorption properties of in-situ synthesized Pt-decorated porous carbons templated from zeolite EMC-2

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordTo increase the interaction between the adsorbed hydrogen and the adsorbent surface to improve the hydrogen storage capacity at ambient temperature, decorating the sorbents with metal nanoparticles, such as Pd, Ni, and Pt has attracted the most attention. In this work, Ptdecorated porous carbons were in-situ synthesized via CVD method using Pt-impregnated zeolite EMC-2 as template and their hydrogen uptake performance up to 20 bar at 77, 87, 298 and 308 K has been investigated with focus on the interaction between the adsorbed H2 and the carbon matrix. It is found that the in-situ generated Pt-decorated porous carbons exhibit Pt nanoparticles with size of 2-4 nm homogenously dispersed in porous carbon, accompanied with observable carbon nanowires on the surface. The calculated H2 adsorption heats at/near 77 K are similar for both the plain carbon (7.8 kJ mol-1) and the Pt-decorated carbon (8.3 kJ mol-1) at H2 coverage of 0.08 wt.%, suggesting physisorption is dominated in both cases. However, the calculated H2 adsorption heat at/near 298 K of Pt-decorated carbon is 72 kJ mol-1 at initial H2 coverage, which decreases dramatically to 20.8 kJ mol-1 at H2 coverage of 0.014 wt.%, levels to 17.9 at 0.073 wt.%, then gradually decreases to 2.6 kJ mol-1 at 0.13 wt.% and closes to that of the plain carbon at H2 coverage above 0.13 wt.%. These results suggest that the introduce of Pt particles significantly enhances the interaction between the adsorbed H2 and the Pt-decorated carbon matrix at lower H2 coverage, resulting in an adsorption process consisting of chemisorption stage, mixed nature of chemisorption and physisorption stage along with the increase of H2 coverage (up to 0.13 wt.%). However, this enhancement in the interaction is outperformed by the added weight of the Pt and the blockage and/or occupation of some pores by the Pt nanoparticles, which results in lower H2 uptake than that of the plain carbon.EU RFCSLeverhulme TrustNational Natural Science Foundation of Chin

    Status of high temperature superconductor based magnets and the conductors they depend upon

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    This paper reviews the status of high temperature superconductors for high field magnets for future devices such as a high energy LHC or a muon collider. Some of the primary challenges faced for the implementation of systems are discussed. Two conductor technologies, Bi2_2Sr2_2CaCu2_2O8+x_{8+x} and YBa2_2Cu3_3O7δ_{7-\delta}, have emerged as high field conductor options, but their relative advantages and disadvantages for high field magnets are quite different. These are reviewed from an engineering perspective, including coil manufacturing, electromechanical behaviour and quench behaviour. Lastly, the important roles of "system pull" upon conductor and magnet technology development, and of interactions between the materials and magnet communities for accelerating development, are discussed.Comment: 11 pages, contribution to the EuCARD-AccNet-EuroLumi Workshop: The High-Energy Large Hadron Collider, Malta, 14 -- 16 Oct 2010; CERN Yellow Report CERN-2011-003, pp. 59-6

    Solar Wind Plasma Entry Observed by Cluster in the High-Latitude Magnetospheric Lobes

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    Using the Cluster data during the period from January to April between 2001 and 2006, we find an observation of solar wind entry due to magnetic reconnection occurred in the terrestrial high-latitude magnetospheric lobes, tailward of the cusps under northward Interplanetary Magnetic Field (IMF). Occurrence rate of solar wind entry events in this study is of the same order as that for the Cluster orbital interval from August to October between the years of 2002 and 2004 as reported by Shi et al [2013]. In this paper, we further study the role of the IMF Bx and By components in the control of solar wind plasmas entry based on the investigations of different magnetic dipole tilt variations between our database and Shi et al. [2013]. This study shows that the asymmetry distribution of solar wind entry events in the northern and southern lobes could be caused by the variation of magnetic dipole tilt, which could influence the locations of the reconnection site on the high latitude lobe magnetopause. On the other hand, IMF Bx can also affect the solar wind plasma entry rate, which is also consistent with previous results. Therefore, we conclude that the “north-south asymmetry” of solar wind entry events in the lobes could be the combined result of magnetic dipole tilt and IMF Bx. In addition, the IMF By component can influence the entry events in conjunction with the variation of IMF Bx component, which is in line with the Parker Spiral of the IMF

    Transpolar arc observation after solar wind entry into the high-latitude magnetosphere

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    Recently, Cluster observations have revealed the presence of new regions of solar wind plasma entry at the high-latitude magnetospheric lobes tailward of the cusp region, mostly during periods of northward interplanetary magnetic field. In this study, observations from the Global Ultraviolet Imager (GUVI) experiment on board the TIMED spacecraft and Wideband Imaging Camera imager on board the IMAGE satellite are used to investigate a possible link between solar wind entry and the formation of transpolar arcs in the polar cap. We focus on a case when transpolar arc formation was observed twice right after the two solar wind entry events were detected by the Cluster spacecraft. In addition, GUVI and IMAGE observations show a simultaneous occurrence of auroral activity at low and high latitudes after the second entry event, possibly indicating a two-part structure of the continuous band of the transpolar arc

    The TIANSHAN Radio Experiment for Neutrino Detection

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    An antenna array devoted to the autonomous radio-detection of high energy cosmic rays is being deployed on the site of the 21 cm array radio telescope in XinJiang, China. Thanks in particular to the very good electromagnetic environment of this remote experimental site, self-triggering on extensive air showers induced by cosmic rays has been achieved with a small scale prototype of the foreseen antenna array. We give here a detailed description of the detector and present the first detection of extensive air showers with this prototype.Comment: 37 pages, 15 figures. Astroparticle Physics (in press
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