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151.
Yasumitsu Matsuo Takehiko Ijichi Hironori Yamada Junko Hatori Seiichiro Ikehata 《Central European Journal of Physics》2004,2(2):357-366
We have fabricated a field effect transistor (FET) based on an organic ferroelectric insulator and molecular conductor, and
investigated the electrical properties and memory effects on the PEN-FET. We have observed a drastic change in the drain current
at around the coercive electric fieldE
c
of the organic ferroelectric insulator in not only a FET (PEN-FET) based on a pentacene (PEN) film but also a FET (IPEN-FET)
based on an iodine doped PEN film. The magnitude of the change of the drain current for the IPEN-FET is 200 times larger than
that for the PEN-FET. It is expected from these results that the PEN-FET (especially the IPEN-FET) is an improvement in such
devices, since it operates at a low gate electric field accompanied by the appearance of the spontaneous polarization in the
organic ferroelectric insulator. In addition, we have found that the drain current for the PEN-FET does not return to the
initial drain current ofE
G
=0 V/cm for more than one week, even if the gate electric field is changed to 0 V/cm from 500 V/cm(>E
c
). From these results, it is suggested that the PEN-FET becomes a memory device. 相似文献
152.
TieYong YangGuangjun 《分析论及其应用》2004,20(1):58-68
In this paper, we construct some continuous but non-differentiable functions defined by quinary decimal, that are Kiesswetter-like functions. We discuss their properties, then investigate the Hausdorff dimensions of graphs of these functions and give a detailed proof. 相似文献
153.
This article provides a status report on discrete mathematics in America's schools, including an overview of publications
and programs that have had major impact. It discusses why discrete mathematics should be introduced in the schools and the
authors' efforts to advocate, facilitate, and support the adoption of discrete mathematics topics in the schools. Their perspective
is that discrete mathematics should be viewed not only as a collection of new and interesting mathematical topics, but, more
importantly, as a vehicle for providing teachers with a new way to think about traditional mathematical topics and new strategies
for engaging their students in the study of mathematics. 相似文献
154.
Byung Kee Kim 《Journal of Applied Mathematics and Computing》2004,14(1-2):185-191
Given a connected graphG, we say that a setC ?V(G) is convex inG if, for every pair of verticesx, y ∈ C, the vertex set of everyx-y geodesic inG is contained inC. The convexity number ofG is the cardinality of a maximal proper convex set inG. In this paper, we show that every pairk, n of integers with 2 ≤k ≤ n?1 is realizable as the convexity number and order, respectively, of some connected triangle-free graph, and give a lower bound for the convexity number ofk-regular graphs of ordern withn>k+1. 相似文献
155.
Hearing and hearing disorders among classical and rock/jazz musicians was investigated. Pure tone audiometry was done in 140 classical and 139 rock/jazz musicians. The rock/jazz musicians answered a questionnaire concerning hearing disorders and psychosocial exposure. All results were compared to age appropriate reference materials. Hearing thresholds showed a notch configuration in both classical and rock/jazz musicians indicating the inclusion of high sound levels but an overall well-preserved hearing thresholds. Female musicians had significantly better hearing thresholds in the high-frequency area than males. Rock/jazz musicians showed slight worse hearing thresholds as compared to classical musicians. When assessing hearing disorders, a large number of rock/jazz musicians suffered from different hearing disorders (74%). Hearing loss, tinnitus and hyperacusis were the most common disorders and were significantly more frequent in comparison with different reference populations. Among classical musicians, no extended negative progress of the pure tone hearing threshold values was found in spite of the continued 16 years of musical noise exposure. In rock/jazz musicians, there was no relationships between psychosocial factors at work and hearing disorders. The rock/jazz musicians reported low stress and high degree of energy. On the average, the rock/jazz musicians reported higher control, lower stress and higher energy than a reference material of white-collar workers. 相似文献
156.
A New Cohomology Theory of Orbifold 总被引:7,自引:0,他引:7
Based on the orbifold string theory model in physics, we construct a new cohomology ring for any almost complex orbifold. The key theorem is the associativity of this new ring. Some examples are computed.Both authors partially supported by the National Science Foundation 相似文献
157.
Gábor Házi 《Central European Journal of Physics》2003,1(3):453-462
A general class of analytical solutions of the lattice Boltzmann equation is derived for two-dimensional, steady-state unidirectional
flows. A subset of the solutions that verifies the corresponding Navier-Stokes equations is given. It is pointed out that
this class includes, e.g., the Couette and the Poiseuille flow but not, e.g., the basic Kolmogorov flow. For steady-state
non-unidirectional flows, first and second order solutions of the lattice Boltzmann equation are derived. Practical consequences of the analysis
are mentioned. Differences between the technique applied here and those used in some earlier works are emphasized. 相似文献
158.
M. De Falco F. De Giovanni C. Musella R. Schmidt 《Rendiconti del Circolo Matematico di Palermo》2003,52(1):70-76
A subgroupH of a groupG is said to bepermutable ifHX=XH for every subgroupX ofG. In this paper the structure of groups in which every subgroup either is abelian or permutable is investigated.
This work was done while the last author was visiting the University of Napoli Federico II. He thanks the “Dipartimento di
Matematica e Applicazioni” for its financial support. 相似文献
159.
We study the elastic responses of double-(ds) and single-stranded (ss) DNA at external force fields. A double-strand-polymer
elastic model is constructed and solved by path integral methods and Monte Carlo simulations to understand the entropic elasticity,
cooperative extensibility, and supercoiling property of dsDNA. The good agreement with experiments indicates that short-ranged
base-pair stacking interaction is crucial for the stability and the high deformability of dsDNA. Hairpin-coil transition in
ssDNA is studied with generating function method. A threshold force is needed to pull the ssDNA hairpin patterns, stabilized
by base pairing and base-pair stacking, into random coils. This phase transition is predicted to be of first order for stacking
potential higher than some critical level, in accordance with experimental observations. 相似文献
160.
The ALEPH Collaboration A. Heister et al. 《The European Physical Journal C - Particles and Fields》2003,29(2):143-170
An improved search for B
s
0 oscillations is performed in the ALEPH data sample collected during the first phase of LEP, and reprocessed in 1998. Three
analyses based on complementary event selections are presented. First, decays of B
s
0 mesons into hadronic flavour eigenstates are fully reconstructed. This selection yields a small sample of candidates with
excellent decay length and momentum resolution and hi gh average B
s
0 purity. Semileptonic decays with a reconstructed
D
s
- meson provide a second sample with larger statistics, high average
B
s
0 purity, but a poorer momentum and decay length resolution due to the partial decay reconstruction. Finally, semileptonic
b-hadron decays are inclusively selected and yield the data sample with the highest sensitivity to B
s
0 oscillations, as the much higher statistics compensate for the low average B
s
0 purity and poorer time resolution. A lower limit is set atps-1 at 95% C.L., significantly lower than the expected limit of 15.2 ps-1.
Received: 21 February 2003 / Published online: 11 June 2003 相似文献