76,045 research outputs found
The Tourism Function of the Castles of the Knights of the Teutonic Order in Poland
The author’s main objective is to define the level of development of the tourism function of the Teutonic Order castles found in the area of contemporary Poland. The author has taken into account both well-preserved and renovated castles, as well as those in a state of ruin. In order to achieve his goal, he analysed forms of castle development and numbers of tourists, which is the main measure of the tourism function. The final stage of the research was to define the tourism rank of the castles studied
Linear electro-optic effects due to high order spatial dispersion
Two new types of electro-optic effect that are linear in the applied electric
field strength are theoretically predicted to exist in transparent dielectric
crystals due to high order spatial dispersion. The first effect, which is
quadratic in the wave vector of light, is possible in materials belonging to
all noncentrosymmetric crystal classes. The second, which is cubic in the wave
vector, is possible in all crystals. In the and crystal classes, for which the primary and secondary linear electro-optic
effects and linear electrogyration are simultaneously absent, these effects
lead, respectively, to qualitatively new behavior and constitute the dominant
bulk electro-optic effect in the limit of small fields. Thus, bulk linear
electro-optic effects are predicted to exist in a wide range of
materials---including many of considerable technological importance, such as
silicon---where they were previously considered impossible.Comment: 10 pages, no figures, additional discussion included. Supplemental
Material available from F. Castles on reques
Design of an adiabatic demagnetization refrigerator for studies in astrophysics
An adiabatic demagnetization refrigerator was designed for cooling infrared bolometers for studies in astrophysics and aeronomy. The design was tailored to the requirements of a Shuttle sortie experiment. The refrigerator should be capable of maintaining three bolometers at 0.1 K with a 90% cycle. The advantage are of operations the bolometer at 0.1K. greater sensitivity, faster response time, and the ability to use larger bolometer elements without compromising the response time. The design presented is the first complete design of an ADR intended for use in space. The most important of these specifications are to survive a Shuttle launch, to operate with 1.5 K - 2.0 K space-pumped liquid helium as a heat sink, to have a 90% duty cycle, and to be highly efficient
A model for the Pockels effect in distorted liquid crystal blue phases
Recent experiments have found that a mechanically distorted blue phase can
exhibit a primary linear electro-optic (Pockels) effect [F. Castles \textit{et
al}. Nature Mater. \textbf{13}, 817 (2014)]. Here it is shown that
flexoelectricity can account for the experimental results and a model, which is
based on continuum theory but takes account of the sub-unit-cell structure, is
proposed. The model provides a quantitative description of the effect accurate
to the nearest order of magnitude and predicts that the Pockels coefficient(s)
in an optimally-distorted blue phase may be two orders of magnitude larger than
in lithium niobate.Comment: 11 pages, 2 figures. Supplemental Material available from F. Castles
on reques
Sub-Kelvin resistance thermometer
A device capable of accurate temperature measurement down to 0.01 K of a particular object is discussed. The device is comprised of the following: a heat sink wafer; a first conducting pad bonded near one end of the heat sink wafer; a second conducting pad bonded near the other end of the heat sink wafer; and an oblong doped semiconductor crystal such as germanium. The oblong doped semiconductor crystal has a third conducting pad bonded on its bottom surface with the oblong doped semiconductor crystal bonded to the heat sink wafer by having the fourth conducting pad bonded to the first conducting pad. A wire is bonded between the second and third conducting pads. Current and voltage wires bonded to the first and second conducting pads measure the change in resistance of the oblong doped semiconductor crystal; this indicates the temperature of the object whose temperature is to be measured
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