2,700 research outputs found

    Space Charge Modelling in Solid Dielectrics under High Electric Field Based on Double Charge Injection Model

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    Present study aims to develop a clear insight on factors that influence space charge dynamics in solid dielectrics through a numerical simulation. The model used for the simulation is proposed by Alison and Hill [1] which describes charge dynamics as a result of bipolar transport with single level trapping. In this model, a constant mobility and no detrapping have been assumed. The simulation results show that carrier mobility, trapping coefficient and Schottky barrier have a significant effect on the space charge dynamics. Many features of space charge profiles observed by experiments have been revealed in despite of over simplistic model. More importantly, the simulation allows us to study the role of each individual parameter in the formation of space charge in solid dielectrics, so that the experimental results can be better understood

    Balanced metrics on homogeneous vector bundles

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    Let EME\rightarrow M be a holomorphic vector bundle over a compact Kaehler manifold (M,ω)(M, \omega) and let E=E1...EmME=E_1\oplus... \oplus E_m\rightarrow M be its decomposition into irreducible factors. Suppose that each EjE_j admits a ω\omega-balanced metric in Donaldson-Wang terminology. In this paper we prove that EE admits a unique ω\omega-balanced metric if and only if rjNj=rkNk\frac{r_j}{N_j}=\frac{r_k}{N_k} for all j,k=1,...,mj, k=1, ..., m, where rjr_j denotes the rank of EjE_j and Nj=dimH0(M,Ej)N_j=\dim H^0(M, E_j). We apply our result to the case of homogeneous vector bundles over a rational homogeneous variety (M,ω)(M, \omega) and we show the existence and rigidity of balanced Kaehler embedding from (M,ω)(M, \omega) into Grassmannians.Comment: 5 page

    The bisymplectomorphism group of a bounded symmetric domain

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    An Hermitian bounded symmetric domain in a complex vector space, given in its circled realization, is endowed with two natural symplectic forms: the flat form and the hyperbolic form. In a similar way, the ambient vector space is also endowed with two natural symplectic forms: the Fubini-Study form and the flat form. It has been shown in arXiv:math.DG/0603141 that there exists a diffeomorphism from the domain to the ambient vector space which puts in correspondence the above pair of forms. This phenomenon is called symplectic duality for Hermitian non compact symmetric spaces. In this article, we first give a different and simpler proof of this fact. Then, in order to measure the non uniqueness of this symplectic duality map, we determine the group of bisymplectomorphisms of a bounded symmetric domain, that is, the group of diffeomorphisms which preserve simultaneously the hyperbolic and the flat symplectic form. This group is the direct product of the compact Lie group of linear automorphisms with an infinite-dimensional Abelian group. This result appears as a kind of Schwarz lemma.Comment: 19 pages. Version 2: minor correction

    Detecting alcohol vapors using two-dimensional copper-based Ruddlesden-Popper perovskites

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    The detection of alcohol vapors has many important applications, such as measuring the breath ethanol content to prevent drug-impaired driving. A medical application is the detection of 1-propanol because this compound was found to be a potential marker for lung cancer screening. This work reports an alcohol sensor using the two-dimensional Ruddlesden-Popper perovskite bis(phenethylammonium) tetrachlorocuprate-(PEA)(2)CuCl4, also known as phenethylammonium copper chloride-as the sensing material. The device is based on a change in conductance upon exposure to alcohol vapors. A comparison between pristine (PEA)(2)CuCl4 and (PEA)(2)CuCl4 after a treatment with ultraviolet light shows that the latter has a higher conductance. Devices made with this UV-converted material show a strong response to 1-propanol vapors, starting from a concentration around 2000 parts per million (ppm). Additionally, these devices demonstrate stable behavior in a nitrogen atmosphere. During the stabilization of the 1-propanol flow rate, the concentration fluctuates. These fluctuations were detected by monitoring the current of the device over time, down to steps in 100ppm around a concentration of 8000ppm. The conductance of the devices decreases in contact with air. However, this process can be reversed by additional ultraviolet illumination, thereby making the devices reusable

    Technology Readiness in Customers’ Perception and Acceptance of M(obile)-Payment: An Empirical Study in Finland, Germany, the USA and Japan

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    In today`s mobile world there is a high potential for m(obile)-payment services, but the mere existence of such services does not mean that the market is ready for them. M-payment services must add value to attract new users. After years of research regarding technology acceptance (TA) of m-payment, the aim of this paper is to examine how technology readiness (TR) influences customers’ perception and acceptance of m-payment. TA of consumers in combination with TR is investigated for m-payment in Finland, Germany, the USA and Japan. We conduct an online survey to collect data in those four countries. We use that data to carry out a TA analysis using a structural equation model (SEM). The research model arises from the findings of a priori explorative study and a comprehensive literature review. Evaluation results based on an extended TA model (TAM) show that user acceptance of m-payment differs influenced by constructs

    Phenomenology of a minimal extension of the standard model with a family-dependent gauge symmetry

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    We consider a gauge symmetry extension of the standard model given by SU(3)CSU(2)LU(1)XU(1)NZ2SU(3)_C\otimes SU(2)_L\otimes U(1)_X\otimes U(1)_N\otimes Z_2 with minimal particle content, where XX and NN are family dependent but determining the hypercharge as Y=X+NY=X+N, while Z2Z_2 is an exact discrete symmetry. In our scenario, XX (while NN is followed by XYX-Y) and Z2Z_2 charge assignments are inspired by the number of fermion families and the stability of dark matter, as observed, respectively. We examine the mass spectra of fermions, scalars, and gauge bosons, as well as their interactions, in presence of a kinetic mixing term between U(1)X,NU(1)_{X,N} gauge fields. We discuss in detail the phenomenology of the new gauge boson and the right-handed neutrino dark matter stabilized by Z2Z_2 conservation. We obtain parameter spaces simultaneously satisfying the recent CDF WW-boson mass, electroweak precision measurements, particle colliders, as well as dark matter observables, if the kinetic mixing parameter is not necessarily small.Comment: 32 pages, 4 figures, 5 tables; Matches published version in PR
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