8,474 research outputs found
A three-dimensional multidimensional gas-kinetic scheme for the Navier-Stokes equations under gravitational fields
This paper extends the gas-kinetic scheme for one-dimensional inviscid
shallow water equations (J. Comput. Phys. 178 (2002), pp. 533-562) to
multidimensional gas dynamic equations under gravitational fields. Four
important issues in the construction of a well-balanced scheme for gas dynamic
equations are addressed. First, the inclusion of the gravitational source term
into the flux function is necessary. Second, to achieve second-order accuracy
of a well-balanced scheme, the Chapman-Enskog expansion of the Boltzmann
equation with the inclusion of the external force term is used. Third, to avoid
artificial heating in an isolated system under a gravitational field, the
source term treatment inside each cell has to be evaluated consistently with
the flux evaluation at the cell interface. Fourth, the multidimensional
approach with the inclusion of tangential gradients in two-dimensional and
three-dimensional cases becomes important in order to maintain the accuracy of
the scheme. Many numerical examples are used to validate the above issues,
which include the comparison between the solutions from the current scheme and
the Strang splitting method. The methodology developed in this paper can also
be applied to other systems, such as semi-conductor device simulations under
electric fields.Comment: The name of first author was misspelled as C.T.Tian in the published
paper. 35 pages,9 figure
Suppression of superconductivity in nanowires by bulk superconductors
Transport measurements were made on a system consisting of a zinc nanowire
array sandwiched between two bulk superconducting electrodes (Sn or In). It was
found that the superconductivity of Zn nanowires of 40 nm diameter is
suppressed either completely or partially by the superconducting electrodes.
When the electrodes are driven into their normal state by a magnetic field, the
nanowires switch back to their superconducting state. This phenomenon is
significantly weakened when one of the two superconducting electrodes is
replaced by a normal metal. The phenomenon is not seen in wires with diameters
equal to and thicker than 70 nm.Comment: 4 pages, 5 figure
Scope of claim coverage in patents of fufang Chinese herbal drugs: Substitution of ingredients
Herbal ingredients in a Chinese fufang prescription are often replaced by one or several other herbal combinations. As there have been very few Chinese herbal patent infringement cases, it is still unclear how the Doctrine of Equivalents should be applied to determine the scope of 'equivalents' in Chinese fufang prescriptions. Case law principles from cases in other technical areas such as chemical patents and biological drug patents can be borrowed to ascertain a precise scope of a fufang patent. This article summarizes and discusses several chemical and biopharmaceutical patent cases. In cases where a certain herbal ingredient is substituted by another herb or a combination of herbs, accused infringers are likely to relate herbal drug patents to chemical drug patents with strict interpretation whereas patent owners may take advantage of the liberal application of Doctrine of Equivalence in biopharmaceutical patents by analogizing the complex nature of herbal drugs with biological drugs. Therefore, consideration should be given to the purpose of an ingredient in a patent, the qualities when combined with the other ingredients and the intended function. The scope of equivalents also depends on the stage of the prior art. Moreover, it is desirable to disclose any potential substitutes when drafting the application. Claims should be drafted in such a way that all foreseeable modifications are encompassed for the protection of the patent owner's intellectual property
Isoproterenol and 8-bromo-cyclic adenosine monophosphate stimulate the expression of the angiotensinogen gene in opossum kidney cells
Isoproterenol and 8-bromo-cyclic adenosine monophosphate stimulate the expression of the angiotensinogen gene in opossum kidney cells. To investigate whether the expression of the renal angiotensinogen (ANG) gene is regulated by β-adrenoceptors and the cAMP-dependent protein kinase A pathway, we introduced stably the fusion gene containing the 5′-flanking regulatory sequence of the ANG gene with a human growth hormone (hGH) gene as a reporter, pOGH (ANG N-1498/+18), into opossum kidney (OK) cells. We successfully obtained several stable transformants with a high expression of the pOGH (ANG N-1498/+18) fusion gene. One stable transformant (OK 27) that is able to maintain the expression of pOGH (ANG N-1498/+18) in culture for more than a year was used in the present study. The level of expression of the pOGH (ANG N-1498/+18) in OK 27 was evaluated by the amount of immunoreactive-hGH (IR-hGH) secreted into the culture medium. The addition of isoproterenol (10-11 M to 10-9 M) stimulated the expression of pOGH (ANG N-1498/+18) and increased the accumulation of intracellular cAMP. Higher concentrations of isoproterenol (that is, greater than 10-9 M) had low or minimal effect. In contrast, the addition of 8-bromo-cAMP (8-Br-cAMP) and forskolin stimulated the expression of pOGH (ANG N-1498/+18) in a dose-dependent manner. The stimulatory effect of isoproterenol was blocked by the presence of propranolol, atenolol and ICI 118,551. The addition of ICI 118,551, however, was less effective than atenolol. Furthermore, the stimulatory effect of isoproterenol and 8-Br-cAMP on the expression of the pOGH (ANG N-1498/+18) was inhibited by the presence of Rp-cAMP (an inhibitor of cAMP-dependent protein kinase AI and II). These studies demonstrated that the expression of the pOGH (ANG N-1498/+18) in OK cells is stimulated by β-adrenoceptors and the cAMP-dependent protein kinase A pathway. Our data indicate that OK 27 cells provide a useful model to study the regulation of expression of the ANG gene in vitro
A Deep Learning Framework for Traffic Data Imputation Considering Spatiotemporal Dependencies
Spatiotemporal (ST) data collected by sensors can be represented as
multi-variate time series, which is a sequence of data points listed in an
order of time. Despite the vast amount of useful information, the ST data
usually suffer from the issue of missing or incomplete data, which also limits
its applications. Imputation is one viable solution and is often used to
prepossess the data for further applications. However, in practice, n practice,
spatiotemporal data imputation is quite difficult due to the complexity of
spatiotemporal dependencies with dynamic changes in the traffic network and is
a crucial prepossessing task for further applications. Existing approaches
mostly only capture the temporal dependencies in time series or static spatial
dependencies. They fail to directly model the spatiotemporal dependencies, and
the representation ability of the models is relatively limited.Comment: accepted at ICITE 202
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