41,401 research outputs found
Fluid valve assembly
A valve assembly is reported for controlling the flow of fluids between the inlet and outlet of a fluid valve. The valve assembly contains a barrier element which is porous for providing fluid communication between the valve inlet and outlet. The valve assembly also includes a sealing element that is movable relative to the barrier element between a first position, in which fluid flow through the porous portion of the barrier element is blocked preventing fluid communication between the valve inlet and outlet, and a second position, in which the porous portion is unblocked, permitting fluid communication between the valve inlet and outlet
Modification of physical properties of freeze-dried rice
Freeze cycling process consists of alternately freezing and thawing precooked rice for two cycles, rice is then frozen and freeze-dehydrated in vacuum sufficient to remove water from rice by sublimitation. Process modifies rice grain structure and porosity, enabling complete rehydration in one minute in hot water
Suppression of the Charge-Density-Wave State in SrCaCuO by External Pressure
The influence of external pressure on the charge-density-wave (CDW) ground
state of the quasi-one-dimensional two-leg ladder compound
SrCaCuO has been studied by optical reflectivity
measurements as a function of temperature (10 - 300~K) and pressure (0.3 -
4.3~GPa) over the spectral range 580 - 6000 cm. With increasing pressure
the CDW transition temperature decreases with the linear pressure
coefficient -70~K/GPa, and above 3~GPa the CDW phase is
suppressed at all temperatures. This behavior is similar to that in compounds
SrCaCuO with increasing Ca content at ambient
pressure, with the simple scaling . The size of the
CDW gap decreases with increasing pressure, whereas the dimensionality of the
high-temperature insulating phase in SrCaCuO within
the ladder plane is hardly affected by external pressure.Comment: accepted for publication in Phys. Rev.
Composite parameterization and Haar measure for all unitary and special unitary groups
We adopt the concept of the composite parameterization of the unitary group
U(d) to the special unitary group SU(d). Furthermore, we also consider the Haar
measure in terms of the introduced parameters. We show that the well-defined
structure of the parameterization leads to a concise formula for the normalized
Haar measure on U(d) and SU(d). With regard to possible applications of our
results, we consider the computation of high-order integrals over unitary
groups.Comment: 28 pages, example and references added, accepted by J. Math. Phy
A composite parameterization of unitary groups, density matrices and subspaces
Unitary transformations and density matrices are central objects in quantum
physics and various tasks require to introduce them in a parameterized form. In
the present article we present a parameterization of the unitary group
of arbitrary dimension which is constructed in a composite
way. We show explicitly how any element of can be composed of
matrix exponential functions of generalized anti-symmetric -matrices
and one-dimensional projectors. The specific form makes it considerably easy to
identify and discard redundant parameters in several cases. In this way,
redundancy-free density matrices of arbitrary rank can be formulated. Our
construction can also be used to derive an orthonormal basis of any
-dimensional subspaces of with the minimal number of
parameters. As an example it will be shown that this feature leads to a
significant reduction of parameters in the case of investigating distillability
of quantum states via lower bounds of an entanglement measure (the
-concurrence).Comment: 13 pages, 1 figur
Preservation of flavor in freeze dried green beans
Before freeze drying, green beans are heated to point at which their cell structure is altered. Beans freeze dried with altered cell structure have improved rehydration properties and retain color, flavor, and texture
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