Results 1 - 10 of 770
Results 1 - 10 of 770. Search took: 0.024 seconds
|Sort by: date | relevance|
[en] We obtained exact analytic solutions of one-dimensional two-particle systems with Dirac-delta repulsive interaction in two typical potentials. It was shown that in these potentials there exists not any wave function symmetrical with respect to the particle exchange. There exist only anti-symmetrical solutions to these systems. Applied to electronic quantum dots, they imply that there exist spin triplet states only and spin singlet states are not allowed for this electronic repulsive interaction
[en] This study employs a multiple-case study method, identifies barriers to the adoption of low carbon production, and categorizes these barriers into four domains: structural, regulatory, cultural, and contextual. The two most frequently mentioned barriers were “lack of financial incentives to stimulate low carbon innovation” and “lack of a common definition of low carbon production”. The two least frequently mentioned barriers were “silos exist between planning and production” and “operational staff are often physically separated from planning staff, which isolates them from planning decisions”. Furthermore, contextual barriers were significantly related to structural and regulatory barriers, while regulatory barriers were significantly related to structural barriers. Larger firms tend to have a more structured organization and lower perceptions of the employment term barrier. However, larger structured organizations have been affected by a long history of a planning-oriented economy and hence tend to have inflexible hierarchical systems. In contrast, small firms have hierarchical systems with less effect on low carbon production than those of large enterprises. Another interesting trend is the direct size effect on cultural barriers, which is evident in a culture of risk aversion, as well as the lack of low carbon technology and the existence of silos between planning and production. - Highlights: • Barriers were categorized as structural, regulatory, cultural and contextual. • Contextual barriers were significantly related to structural and regulatory barriers. • Regulatory barriers were significantly related to structural barriers. • Firm size directly affected firm hierarchical systems and cultural barriers
[en] HL-2A is a new divertor tokamak under construction at Southwestern Institute of Physics (SWIP), Chengdu, China, based on the experience from HL-1 and HL-1M. The main objectives of HL-2A are to produce more adaptable divertor configurations to study energy exhaust and impurity control, and study enhanced plasma confinement by profile control and moderate plasma shaping. The status and plan of the HL-2A project are described in this paper. they include development of the HL-2A tokamak, installation of HL-2A, experimental program of HL-2A and future plan
[en] This paper explores the empirical evidence of the link between residents’ low-carbon awareness and their behaviors in China. A questionnaire measuring seven dimensions (including low-carbon knowledge, low-carbon value, low-carbon attitude, private low-carbon behavior, public low-carbon behavior, barrier and motivator) was distributed to the residents of Tianjin, yielding 354 valid responses. The results indicated that there was a low-carbon awareness–behavior gap. In particular, the level of behavior was higher than awareness because the motivators were stronger than the barriers. Second, in exploring the affects of motivators versus barriers on the residents’ private and public low-carbon behaviors, we found that motivators promoted both private and public low-carbon behaviors while barriers significantly inhibited public low-carbon behaviors. Third, Chinese social and cultural factors are discussed to inform our exploration of the mechanisms forming the residents’ awareness–behavior gap. - Highlights: • There was a low-carbon awareness–behavior gap. • The level of behavior was higher than awareness. • The motivators promoted both private and public low-carbon behaviors. • The barriers significantly inhibited public low-carbon behaviors
[en] Starting from the shell model configuration and the effective nucleon-nucleon interaction, a microscopic approach is presented to study high spin states of even-even nuclei in the truncated shell model space. The neutron and proton degrees of freedom are distinguished as the approach is applied to the description of nuclei 168Hf. From the results, one can see that the approach provides a new way to describe the properties of high spin states
[en] The similarity and difference of LBB and BP piping design were analyzed from the aspect of their design philosophy, as well as the material quality requirement, fabrication requirement, application scope, leak detection, crack analysis, local effect and global effect. The research results show that BP's 'defense in depth' system encompasses the main content of LBB. Requirements of BP pipe are more complicated than that of LBB. Local effect and global effect of primary coolant pipes between application of LBB concept and that of BP concept are almost the same. (author)
[en] HL-2A will be equipped with a 75 GHz/1 MW/1 s electron cyclotron resonance heating (ECRH) system. The paper describes the design of the transmission system, which is made up of a transmission line, an equatorial launcher and a measureing system. The paper describes in detail the design of main components of the system such as, waveguides, ellipsoidal surface mirrors, chemical vapor (CVD) diamond window, steering mirror, and new directional coupler with a k-spectrometer. The newly-designed launcher can make the beam steer poloidally to deposit energy in different locations. (author)
[en] A new-type of lower hybrid wave (LHW) launcher which can work as active and passive waveguide array alternately is described. Its physical model and calculation method are given. The power spectrum and the reflection properties of the launcher are studied. For the mean reflection coefficients of the active waveguide, and the directivity coefficients of the transmitted power spectrum and their dependences on the plasma parameters and the launcher parameters are calculated. More precise analyses of the properties of the LHCD launcher on the HL-1M tokamak are given
[en] Highlights: • NDMA formation mechanisms from dimethylamine in chloramination/ozonation were reinvestigated by G4 method. • The reactivity order of halo-/hydroxyl-amines reacting with dimethylamine is NHCl_2 ∼ NHBrCl > NH_2Cl >> NH_2OH. • Nitrene compound is an important intermediate to form NDMA in oxidation reaction. • Oxidation of unsymmetrical dimethylhydrazine by O_2 is significantly less feasible compared to that by O_3. • The amines containing the second nitrogen source are potential NDMA precursors in ozonation. - Abstract: N-nitrosodimethylamine (NDMA) as a disinfection by-product has recently become the focus of considerable research interest due to its unusually high carcinogenicity. In this study, the formation mechanisms of NDMA from dimethylamine (DMA) during chloramination and ozonation were investigated by using the quantum chemical G4 method. The reactivity of haloamines and hydroxylamine reacting with DMA was found in the order: NHCl_2 ∼ NHBrCl (Br"-leaving) > NHBr_2 > NH_2Cl ∼ NH_2Br >> NH_2OH. This offers a theoretical support for the experimentally proposed mechanism that dimethylamine reacts with NHCl_2 rather than NH_2Cl to form chlorinated unsymmetrical dimethylhydrazine intermediate and the existence of bromochloramine in the presence of bromide during chloramination, and explains the observation that NDMA yield during ozonation is much lower than that during chloramination. Importantly, an N,N-dimethylaminonitrene was found to be a significant intermediate to form NDMA in oxidation reactions by molecular oxygen and ozone. Additionally, results suggest that the amines containing the second nitrogen source directly connecting or close to the N-(CH_3)_2 moiety are potential significant NDMA precursors upon ozonation. The findings of this study are helpful for expanding the knowledge of NDMA formation mechanism, and predicting potential NDMA precursors during disinfection.
[en] A technological prototype of a highly granular sampling hadron calorimeter (HCAL) based on scintillator tiles and silicon photomultipliers (SiPMs) is being developed within the CALICE collaboration. Driven by the need of an automated mass assembly of around 8 million channels of the final HCAL, we developed a design of scintillator tiles directly coupled to surface-mounted SiPMs and successfully built an HCAL readout unit with 144 channels via mass assembly. Results of extensive performance tests will be shown. Further studies on the characterisation of a novel SiPM with extremely low noise as well as tile design optimisations for the next generation of HCAL readout units will also be presented.