1,255 research outputs found
Rotational Spectroscopy Meets Quantum Chemistry for Analyzing Substituent Effects on Non-Covalent Interactions: The Case of the Trifluoroacetophenone-Water Complex
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
Discussion on the Water-Saving Technology of the Green Community
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
Nonlinear Decoherence in Quantum State Preparation of a Trapped Ion
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
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
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, BiSrCaCuO and
YBaCuO, 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
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
How to reduce anxiety symptoms through individual sport in youth: A longitudinal study over 8-month observation.
This is the final version. Available from SAGE Publications via the DOI in this record. BACKGROUND: Anxiety symptoms are widely observed among the youth, and engagement in sports has been demonstrated to mitigate these symptoms. Nonetheless, the effectiveness of specific sports and the potential moderating role of psychological factors, such as self-esteem and self-efficacy, on the influence of sports on anxiety, remains to be elucidated. This study was designed to longitudinally assess the impact of sports participation on anxiety symptoms among young individuals. METHODS: The study encompassed 163 university students, with a male predominance of 81.6%, and explored the influence of sport-related factors (such as mastery of table tennis skills, level and engagement) and psychological aspects (including self-efficacy, self-esteem and resilience) on anxiety symptoms, employing an 8-month longitudinal approach. Physical activity, sedentary and sleep behaviour, along with age, body mass index (BMI), and sex, were accounted for as confounding variables. RESULTS: The study found that high table tennis performance score was found to buffer the development of anxiety symptoms in students with decreased self-esteem in an exploratory moderation model. Self-esteem and self-efficacy were negatively associated with the development of anxiety symptoms, whereas physical activity factors did not have a direct effect. CONCLUSION: This study highlights the potential of table tennis as a form of sport to alleviate anxiety symptoms in university students, particularly among those with decreased self-esteem. Future research should address the study's limitations and explore the potential moderating effects of other psychological factors. Overall, these findings suggest a potential new approach to treating anxiety symptoms among university students
Transpolar arc observation after solar wind entry into the high-latitude magnetosphere
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
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