99 research outputs found
Mirror symmetry breaking through an internal degree of freedom leading to directional motion
We analyze here the minimal conditions for directional motion (net flow in
phase space) of a molecular motor placed on a mirror-symmetric environment and
driven by a center-symmetric and time-periodic force field. The complete
characterization of the deterministic limit of the dissipative dynamics of
several realizations of this minimal model, reveals a complex structure in the
phase diagram in parameter space, with intertwined regions of pinning (closed
orbits) and directional motion. This demonstrates that the mirror-symmetry
breaking which is needed for directional motion to occur, can operate through
an internal degree of freedom coupled to the translational one.Comment: Accepted for publication in Phys. Rev.
Relativistic graphene ratchet on semidisk Galton board
Using extensive Monte Carlo simulations we study numerically and analytically
a photogalvanic effect, or ratchet, of directed electron transport induced by a
microwave radiation on a semidisk Galton board of antidots in graphene. A
comparison between usual two-dimensional electron gas (2DEG) and electrons in
graphene shows that ratchet currents are comparable at very low temperatures.
However, a large mean free path in graphene should allow to have a strong
ratchet transport at room temperatures. Also in graphene the ratchet transport
emerges even for unpolarized radiation. These properties open promising
possibilities for room temperature graphene based sensitive photogalvanic
detectors of microwave and terahertz radiation.Comment: 4 pages, 4 figures. Research done at Quantware
http://www.quantware.ups-tlse.fr/. More detailed analysis is give
Generalized quantum Fokker-Planck, diffusion and Smoluchowski equations with true probability distribution functions
Traditionally, the quantum Brownian motion is described by Fokker-Planck or
diffusion equations in terms of quasi-probability distribution functions, e.g.,
Wigner functions. These often become singular or negative in the full quantum
regime. In this paper a simple approach to non-Markovian theory of quantum
Brownian motion using {\it true probability distribution functions} is
presented. Based on an initial coherent state representation of the bath
oscillators and an equilibrium canonical distribution of the quantum mechanical
mean values of their co-ordinates and momenta we derive a generalized quantum
Langevin equation in -numbers and show that the latter is amenable to a
theoretical analysis in terms of the classical theory of non-Markovian
dynamics. The corresponding Fokker-Planck, diffusion and the Smoluchowski
equations are the {\it exact} quantum analogues of their classical
counterparts. The present work is {\it independent} of path integral
techniques. The theory as developed here is a natural extension of its
classical version and is valid for arbitrary temperature and friction
(Smoluchowski equation being considered in the overdamped limit).Comment: RevTex, 16 pages, 7 figures, To appear in Physical Review E (minor
revision
Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET
The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
Relationship of edge localized mode burst times with divertor flux loop signal phase in JET
A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM
PROFIL WISATAWAN MUSEUM RADYA PUSTAKA SURAKARTA
Anggit Margaret, C9407031 2011. Profil Wisatawan Museum
Radya Pustaka Surakarta. Program Studi Diploma III Usaha Perjalanan
Wisata Fakultas Sastra Dan Seni Rupa Universitas Sebelas Maret Surakarta.
Penelitian tugas akhir ini mengkaji tentang Profil Wisatawan di
Museum Radya Pustaka Surakarta. Tujuan dari penelitian ini adalah untuk
mengetahui dari daerah mana saja wisatawan yang berkunjung ke Museum
Radya Pustaka, bagaimana ciri-ciri wisatawan yang berkunjung ke Museum
Radya Pustaka serta harapan-harapan yang diinginkan wisatawan terhadap
Museum Radya Pustaka.
Penelitian dilakukan dengan metode kualitatif. Pengumpulan data
dilakukan melalui wawancara dengan narasumber wisatawan yang berkujung
di Museum Radya Pustaka Surakarta tempat penulis melakukan penelitian,
serta studi pustaka dan studi dokumen guna menambah sumber data.
Hasil penelitian menunjukkan bahwa (1) Sebagian besar wisatawan
yang datang berasal dari Semarang sebesar 32%. (2) Mayoritas wisatawan
yang berkunjung ke Museum Radya Pustaka berusia antara 17-25 tahun dan
kebanyakan dari mereka adalah pelajar atau mahasiswa dengan prosentase
52%. (3) Sebagian besar wisatawan yang datang ke Museum Radya Pustaka
adalah bertujuan untuk melakukan penelitian yaitu sebesar 34%. (4) Harapan
wisatawan yang berkunjung terhadap kelangsungan Museum Radya Pustaka
sebagian besar adalah agar ditingkatkan lagi pengelolaan dan keamanan
museum, agar kejadian hilangnya benda-benda koleksi museum tidak terulang
lagi dikemudian hari.
Kesimpulan dari hasil penelitian ini bahwa wisatawan yang berkujung
ke Museum Radya Pustaka Surakarta mayoritas berasal dari Semarang,
mayoritas berusia 17-25 tahun dan kebanyakan dari mereka adalah berprofesi
sebagai pelajar dan mahasiswa. Kebanyakan wisatawan yang datang bertujuan
untuk melakukan penelitian, serta harapan wisatawan terhadap Museum
Radya Pustaka adalah supaya lebih ditingkatkan lagi pengelolaan dan
keamanan museum
Systematically evaluating the effectiveness of quality assurance programmes in leading to improvements in institutional performance
Relation between Phagocytic Activity and Alkaline Phosphatase Content of Neutrophils in Chronic Myeloid Leukaemia
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