1,149 research outputs found
The first basic boundary value problem of Riemann's type for bianalytical functions in a plane with slots
The paper is devoted to the investigation of one of the basic boundary value problems of Riemann's type for bianalytical functions. In the course of work there was made out a constructive method for solution of the problem given in a plane with slots. There was also found out that the solution of the problem under consideration consists of consequent solutions of two Riemann's boundary value problems for analytical functions in a plane with slots. Besides, a picture of solvability of the problem is being searched and its Noether is identified.
Apie pirmojo pagrindinio kraštinio Rimano tipo uždavinio bianalizinėms funkcijoms plokštumoje su įtrūkiai sprendimą
Santrauka
Šiame darbe tyrinejamas uždavinys, kai ieškoma dalimis bianaliziniu funkciju, nykstančiu begalybeje, apribotu greta kontūro trūkio tašku ir šiame kontūre tenkinančiu dvi kraštines salygas. Parodoma, kad sprendžiamas uždavinys suvedamas i sprendima dvieju Rimano uždaviniu analizinems funkcijoms.
First Published Online: 14 Oct 201
Efficiency of monolaurin in mitigating ruminal methanogenesis and modifying C-isotope fractionation when incubating diets composed of either C3 or C4 plants in a rumen simulation technique (Rusitec) system
Mitigation of methanogenesis in ruminants has been an important goal for several decades. Free lauric acid, known to suppress ruminal methanogenesis, has a low palatability; therefore, in the present study the aim was to evaluate the mitigation efficacy of its esterified form (monolaurin). Further, 13C-isotope abundance (δ13C) and 13C-12C fractionation during methanogenesis and fermentation were determined to evaluate possible microbial C-isotope preferences. Using the rumen simulation technique, four basal diets, characterised either by the C3 plants grass (hay) and wheat (straw and grain), or the C4 plant (13C excess compared with C3 plants) maize (straw and grain), and a mixture of the latter two, were incubated with and without monolaurin (50g/kg dietary DM). Added to hay, monolaurin did not significantly affect methanogenesis. When added to the other diets (P<0·05 for the wheat-based diet) methane formation was lowered. Monolaurin decreased fibre disappearance (least effect with the hay diet), acetate:propionate ratio, and protozoal counts. Feed residues and SCFA showed the same δ13C as the diets. Methane was depleted in 13C while CO2 was enriched in 13C compared with the diets. Monolaurin addition resulted in 13C depletion of CO2 and enrichment in CH4 (the latter only in the hay diet). In conclusion, monolaurin proved to effectively decrease methanogenesis in the straw-grain diets although this effect might partly be explained by the concomitantly reduced fibre disappearance. The influence on 13C-isotope abundance and fractionation supports the hypothesis that ruminal microbes seem to differentiate to some extent between C-isotopes during methanogenesis and fermentatio
The Non-Trapping Degree of Scattering
We consider classical potential scattering. If no orbit is trapped at energy
E, the Hamiltonian dynamics defines an integer-valued topological degree. This
can be calculated explicitly and be used for symbolic dynamics of
multi-obstacle scattering.
If the potential is bounded, then in the non-trapping case the boundary of
Hill's Region is empty or homeomorphic to a sphere.
We consider classical potential scattering. If at energy E no orbit is
trapped, the Hamiltonian dynamics defines an integer-valued topological degree
deg(E) < 2. This is calculated explicitly for all potentials, and exactly the
integers < 2 are shown to occur for suitable potentials.
The non-trapping condition is restrictive in the sense that for a bounded
potential it is shown to imply that the boundary of Hill's Region in
configuration space is either empty or homeomorphic to a sphere.
However, in many situations one can decompose a potential into a sum of
non-trapping potentials with non-trivial degree and embed symbolic dynamics of
multi-obstacle scattering. This comprises a large number of earlier results,
obtained by different authors on multi-obstacle scattering.Comment: 25 pages, 1 figure Revised and enlarged version, containing more
detailed proofs and remark
Minimum Conductivity and Evidence for Phase Transitions in Ultra-clean Bilayer Graphene
Bilayer graphene (BLG) at the charge neutrality point (CNP) is strongly
susceptible to electronic interactions, and expected to undergo a phase
transition into a state with spontaneous broken symmetries. By systematically
investigating a large number of singly- and doubly-gated bilayer graphene (BLG)
devices, we show that an insulating state appears only in devices with high
mobility and low extrinsic doping. This insulating state has an associated
transition temperature Tc~5K and an energy gap of ~3 meV, thus strongly
suggesting a gapped broken symmetry state that is destroyed by very weak
disorder. The transition to the intrinsic broken symmetry state can be tuned by
disorder, out-of-plane electric field, or carrier density
Screening and interlayer coupling in multilayer graphene field-effect transistors
With the motivation of improving the performance and reliability of
aggressively scaled nano-patterned graphene field-effect transistors, we
present the first systematic experimental study on charge and current
distribution in multilayer graphene field-effect transistors. We find a very
particular thickness dependence for Ion, Ioff, and the Ion/Ioff ratio, and
propose a resistor network model including screening and interlayer coupling to
explain the experimental findings. In particular, our model does not invoke
modification of the linear energy-band structure of graphene for the multilayer
case. Noise reduction in nano-scale few-layer graphene transistors is
experimentally demonstrated and can be understood within this model as well.Comment: 13 pages, 4 figures, 20 reference
Design and Test of the Payload Electronics and In Flight Sequence Development for the CSUNSAT1 Low Temperature Battery Experiment
No abstract availabl
A theoretical study of the structural phases of Group 5B - 6B metals and their transport properties
In order to predict the stable and metastable phases of the bcc metals in the
block of the Periodic Table defined by groups 5B to 6B and periods 4 to 6, as
well as the structure dependence of their transport properties, we have
performed full potential computations of the total energies per unit cell as a
function of the c/a ratio at constant experimental volume. In all cases, a
metastable body centered tetragonal (bct) phase was predicted from the
calculations. The total energy differences between the calculated stable and
metastable phases ranged from 0.09 eV/cell (vanadium) to 0.39 eV/cell
(tungsten). The trends in resistivity as a function of structure and atomic
number are discussed in terms of a model of electron transport in metals.
Theoretical calculations of the electrical resistivity and other transport
properties show that bct phases derived from group 5B elements are more
conductive than the corresponding bcc phases, while bct phases formed from
group 6B elements are less conductive than the corresponding bcc phases.
Special attention is paid to the phases of tantalum where we show that the
frequently observed beta phase is not a simple tetragonal distortion of bcc
tantalum
Single valley Dirac fermions in zero-gap HgTe quantum wells
Dirac fermions have been studied intensively in condensed matter physics in
recent years. Many theoretical predictions critically depend on the number of
valleys where the Dirac fermions are realized. In this work, we report the
discovery of a two dimensional system with a single valley Dirac cone. We study
the transport properties of HgTe quantum wells grown at the critical thickness
separating between the topologically trivial and the quantum spin Hall phases.
At high magnetic fields, the quantized Hall plateaus demonstrate the presence
of a single valley Dirac point in this system. In addition, we clearly observe
the linear dispersion of the zero mode spin levels. Also the conductivity at
the Dirac point and its temperature dependence can be understood from single
valley Dirac fermion physics.Comment: version 2: supplementary material adde
Role of peripheral quantitative computed tomography in identifying disuse osteoporosis in paraplegia
Objective: Disuse osteoporosis is a major long-term health consequence of spinal cord injury (SCI) that still needs to be addressed. Its management in SCI should begin with accurate diagnosis, followed by targeted treatments in the most vulnerable subgroups. We present data quantifying disuse osteoporosis in a cross-section of the Scottish paraplegic population to identify subgroups with lowest bone mineral density (BMD).
Materials and Methods: Forty-seven people with chronic SCI at levels T2-L2 were scanned using peripheral Quantitative Computed Tomography (pQCT) at four tibial sites and two femoral sites, at the Queen Elizabeth National Spinal Injuries Unit, Glasgow (U.K.). At the distal epiphyses, trabecular BMD (BMDtrab), total BMD, total bone cross-sectional area (CSA), and bone mineral content (BMC) were determined. In the diaphyses, cortical BMD, total bone CSA, cortical CSA, and BMC were calculated. Bone, muscle and fat CSAs were estimated in the lower leg and thigh.
Results: BMDtrab decreased exponentially with time since injury, at different rates in the tibia and femur. At most sites, female paraplegics had significantly lower BMC, total bone CSA and muscle CSA than male paraplegics. Subjects with lumbar SCI tended to have lower bone values and smaller muscle CSAs than in thoracic SCI.
Conclusion: At the distal epiphyses of the tibia and femur, there is generally a rapid and extensive reduction in BMDtrab after SCI. Female subjects, and those with lumbar SCI, tend to have lower bone values than males or those with thoracic SCI, respectively.
Keywords: Bone loss, osteoporosis, paraplegia, peripheral Quantitative Computed Tomography, spinal cord injur
Utilization of a Buffered Dielectric to Achieve High Field-Effect Carrier Mobility in Graphene Transistors
We utilize an organic polymer buffer layer between graphene and conventional
gate dielectrics in top-gated graphene transistors. Unlike other insulators,
this dielectric stack does not significantly degrade carrier mobility, allowing
for high field-effect mobilities to be retained in top-gate operation. This is
demonstrated in both two-point and four-point analysis, and in the
high-frequency operation of a graphene transistor. Temperature dependence of
the carrier mobility suggests that phonons are the dominant scatterers in these
devices
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