1,191 research outputs found
Embeddability of some strongly pseudoconvex CR manifolds
We obtain an embedding theorem for compact strongly pseudoconvex CR manifolds
which are bounadries of some complete Hermitian manifolds. We use this to
compactify some negatively curved Kaehler manifolds with compact strongly
pseudoconvex boundary. An embedding theorem for Sasakian manifolds is also
derived.Comment: 12 pages, AMSLate
Insights from teaching European economic integration to non-economic students
The aim of this paper is to identify, analyze and assess the main challenges, difficulties and benefits of teaching European economic integration to non-economic students. The paper draws on evidence from a series of courses delivered within the framework of a Jean Monnet European Module to students registered in different faculties of Transilvania University of Brasov. The results of the teaching activity can be measured in terms of the number of students participating in the lectures and tutorials, the quality of their exam papers and essays submitted for evaluation as well as the share of students finally graduating the Module
Prenatal diagnosis of trisomy 6q25.3-qter and monosomy 10q26.12-qter by array CGH in a fetus with an apparently normal karyotype.
We present the prenatal case of a 12.5-Mb duplication involving 6q25-qter and a 12.2-Mb deletion encompassing 10q26-qter diagnosed by aCGH, while conventional karyotype showed normal results. The genotype-phenotype correlation between individual microarray and clinical findings adds to the emerging atlas of chromosomal abnormalities associated with specific prenatal ultrasound abnormalities
Control structure for single-phase stand-alone wind-based energy sources
This paper is analyzing the operation of a standalone wind turbine system with variable speed Permanent Magnet Synchronous Generator (PMSG) and a system for storing energy during wind speed and load variations. Energy storage devices are required for power balance and power quality in stand alone wind energy systems. Initially, the holistic model of the entire system is achieved, including the PMSG, the boost converter and the storage system. The power absorbed by the connected loads can be effectively delivered and supplied by the proposed wind turbine and energy storage systems, subject to an appropriate control method. The main purpose is to supply 230 V/50 Hz domestic appliances through a single-phase inverter. The simulation results, validated by experimental testing, show a good prediction of the electrical parameter waveforms. The control system is implemented on a dSPACE DS1103 real-time
board. Furthermore, the results confirm the stability of the supply
A REVIEW OF PHYTOREMEDIATION STRATEGIES FOR SOILS POLLUTED WITH HEAVY METALS
Mining operations, industrial production and domestic and agricultural use of metal and metal containing compound have resulted in the release of toxic metals into the environment. Heavy metal pollution has serious implications for the human health and the environment. Since heavy metals are nonbiodegradable, they accumulate in the environment and subsequently contaminate the food chain. Few heavy metals are toxic and lethal in trace concentrations and can be teratogenic, mutagenic, endocrine disruptors while others can cause behavioral and neurological disorders among infants and children. Therefore, remediation of heavy metals contaminated soil could be the only effective option to reduce the negative effects on ecosystem health. Different physical and chemical methods used for this purpose suffer from serious limitations like high cost, intensive labor, alterationof soil properties and disturbance of soil native microorganisms. Phytoremediationis the use of plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. In this article are reviewed the stratagies in the phytoremediation for remediating heavy metals from polluted soils. Phytoextraction and phytostabilization are the most promising and alternative methods for soil reclamation
Macrodimers: ultralong range Rydberg molecules
We study long range interactions between two Rydberg atoms and predict the
existence of ultralong range Rydberg dimers with equilibrium distances of many
thousand Bohr radii. We calculate the dispersion coefficients ,
and for two rubidium atoms in the same excited level , and find
that they scale like , and , respectively. We show that
for certain molecular symmetries, these coefficients lead to long range
potential wells that can support molecular bound levels. Such macrodimers would
be very sensitive to their environment, and could probe weak interactions. We
suggest experiments to detect these macrodimers.Comment: 4 pages, submitted to PR
Calculation of the interspecies s-wave scattering length in an ultracold Na-Rb vapor
We report the calculation of the interspecies scattering length for the
sodium-rubidium (Na-Rb) system. We present improved hybrid potentials for the
singlet and triplet ground states of the NaRb
molecule, and calculate the singlet and triplet scattering lengths and
for the isotopomers NaRb and NaRb. Using
these values, we assess the prospects for producing a stable two-species
Bose-Einstein condensate in the Na-Rb system.Comment: v2: report correct units in Table captions, fix error in conclusions
for NaRb TBEC. Otherwise, more concise presentation, typos
fixed. 6 pages, 1 figur
A note on the calculation of the effective range
The closed form of the first order non-linear differential equation that is
satisfied by the effective range within the variable phase formulation of
scattering theory is discussed. It is shown that the conventional method of
determining the effective range, by fitting a numerical solution of the
Schr\"odinger equation to known asymptotic boundary conditions, can be modified
to include the first order contribution of a long range interaction.Comment: 4 page
Lithium-ion battery degradation: measuring rapid loss of active silicon in silicon-graphite composite electrodes
To increase the specific energy of commercial lithium-ion batteries, silicon is often blended into the graphite negative electrode. However, due to large volumetric expansion of silicon upon lithiation, these silicon–graphite (Si–Gr) composites are prone to faster rates of degradation than conventional graphite electrodes. Understanding the effect of this difference is key to controlling degradation and improving cell lifetimes. Here, the effects of state-of-charge and temperature on the aging of a commercial cylindrical cell with a Si–Gr electrode (LG M50T) are investigated. The use of degradation mode analysis enables quantification of separate rates of degradation for silicon and graphite and requires only simple in situ electrochemical data, removing the need for destructive cell teardown analyses. Loss of active silicon is shown to be worse than graphite under all operating conditions, especially at low state-of-charge and high temperature. Cycling the cell over 0–30% state-of-charge at 40 °C resulted in an 80% loss in silicon capacity after 4 kA h of charge throughput (∼400 equiv full cycles) compared to just a 10% loss in graphite capacity. The results indicate that the additional capacity conferred by silicon comes at the expense of reduced lifetime. Conversely, reducing the utilization of silicon by limiting the depth-of-discharge of cells containing Si–Gr will extend their lifetime. The degradation mode analysis methods described here provide valuable insight into the causes of cell aging by separately quantifying capacity loss for the two active materials in the composite electrode. These methods provide a suitable framework for any experimental investigations involving composite electrodes
Ab initio calculation of the KRb dipole moments
The relativistic configuration interaction valence bond method has been used
to calculate permanent and transition electric dipole moments of the KRb
heteronuclear molecule as a function of internuclear separation. The permanent
dipole moment of the ground state potential is found to be
0.30(2) at the equilibrium internuclear separation with excess negative
charge on the potassium atom. For the potential the dipole moment
is an order of magnitude smaller (1 Cm) In addition, we
calculate transition dipole moments between the two ground-state and
excited-state potentials that dissociate to the K(4s)+Rb(5p) limits. Using this
data we propose a way to produce singlet KRb molecules by a
two-photon Raman process starting from an ultracold mixture of doubly
spin-polarized ground state K and Rb atoms. This Raman process is only allowed
due to relativistic spin-orbit couplings and the absence of gerade/ungerade
selection rules in heteronuclear dimers.Comment: 16 pages, 7 figure
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