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81 
Unusual radiation characteristics in vacuum and in some anisotropic media. / CUHK electronic theses & dissertations collectionJanuary 2000 (has links)
Xu Bai Yu. / "August 22, 2000." / Thesis (Ph.D.)Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. [164]169). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

82 
Nature Abhors an Empty VacuumMinsky, Marvin 01 August 1981 (has links)
Imagine a crystalline world of tiny, discrete "cells", each knowing only what its nearest neighbors do. Each volume of space contains only a finite amount of information, because space and time come in discrete units. In such a universe, we'll construct analogs of particles and fields ??d ask what it would mean for these to satisfy constraints like conservation of momentum. In each case classical mechanics will break down ?? scales both small and large, and strange phenomena emerge: a maximal velocity, a slowing of internal clocks, a bound on simultaneous measurement, and quantumlike effects in very weak or intense fields. This fantasy about conservation in cellular arrays was inspired by this first conference on computation and physics, a subject destined to produce profound and powerful theories. I wish this essay could include one such; alas, it only portrays images of what such theories might be like. The "cellular array" idea is popular already in such forms as Ising models, renormalization theories, the "Game of Life" and Von Neumann's work on selfproducing machines. This essay exploits many unpublished ideas I got from Edward Fredkin. The ideas about field and particle are original; Richard Feynman persuaded me to consider fields instead of forces, but is not responsible for my compromise on potential surfaces. I also thank Danny Hillis and Richard Stallman for other ideas.

83 
(¤@) Pyrolytic Study of (4Methoxystyryl)pyridenes (¤G) Pyrolytic and Photolytic Studies of orthoChlorostyrylarenesJiang, Chiounan 21 August 2007 (has links)
(¤@)FVP of (4Methoxystyryl)pyridenes gave the corresponding phenol products 18 and tricyclic products 20, which all included indene structure.
(¤G)FVP of orthoChlorostyrylarenes gave the cyclized prodccts 17, which eliminated chloro group. Photolytic study of orthoChlorostyrylarenes gave chlorocontaining cyclized products 22.

84 
Vacuum Energy in Expanding Spacetime and Superoscillation  Induced ResonancePrain, Angus January 2008 (has links)
This thesis is divided into two parts. The first part is a study of
the general problem of vacuum energy or socalled `zero point
fluctuations' of a quantum field on expanding spacetimes and the
interplay between the dilution of energy as a mode expands and the
generation of energy as new modes enter from below the ultraviolet
cutoff. The second deals with the phenomenon of superoscillations
and some of the consequences in quantum theory and cosmology.
Modern theoretical cosmology sits upon the theory of inflation
which assumes that the universe underwent a period of accelerated
expansion sometime in the past. Indeed, a whole new scientific
discipline was born known as high precision observational cosmology
when ground breaking detailed measurements were made in the late
1990's that confirmed some predictions of the theory of inflation.
However, inflation is essentially a classical phenomenon with the
inclusion of the quantum theory relegated to the provision of
initial perturbations of an otherwise homogeneous and isotropic
spacetime usually interpreted as the inexorable quantum fluctuations
of a (classical) scalar field coupled to the metric.
Quantum field theory on curved spacetime, on the other hand, has
some novel features in comparison to it's flat spacetime cousin. The
inclusion of some of these effects into a discussion of the novel
inflationary picture should provide some very interesting and
nontrivial insights to the very early universe and perhaps might
shed some light on the fundamental nature of the gravitational
interaction itself. Usually when studying quantum fields in curved
spacetime and the energetic interaction between gravity and the
quanta one works in the semiclassical picture where gravity remains
a classical field. This is not only because a fully consistent
quantum theory of gravity has not been constructed yet. Indeed,
there should exist a presumably quite extensive regime where the
picture of quantum fields propagating on a classical background
remains a valid approximation. In the first part of this thesis we
study this regime and some of the interesting physics that arises.
Eventually, however, we go one step further than a semiclassical
treatment and investigate the hypothesis that the dynamics of
cosmologically significant spacetimes is provided by the spacetime
dependence of the quantum vacuum energy of a scalar field on
that spacetime. Put more simply, we discuss the possibility that the
tendency for a spacetime to expand and accelerate it's expansion
reduces to the statement that it is vacuumenergetically favorable
to do so. The idea that the gravitational degrees of freedom are
induced in this way is an old one due to Sakharov and is one
represented in this thesis in simplified form and with specific
calculations and examples. We find that such an interpretation is at
least not excluded and, in fact, sits satisfactorily with the ideas
of inflation.
Along the way to our conclusive discussion of the `induced
cosmology' we discuss, after briefly reviewing inflation and quantum
field theory in curved spacetime, the general problem of vacuum
energy in curved spacetime and some simplified models of the quantum
mechanical ground state energy of a collection of harmonic
oscillators on expanding spaces including some discrete models. Our
philosophy throughout will be one of pragmatism; we assume a cutoff
on momenta (or length scales) at an unspecified energy scale and
assume our conclusions hold, if not all the way from the Planck
scale (which would presumably be subject to beyond the standard
model `quantum gravitational' effects), then at least in some
mesoscale between the Hubble scale and the Planck scale. It is
certainly true that a quantum scalar field really is a collection of
independent harmonic oscillators one for each different comoving
length scale (wavelength). The question that we seek to address in
this thesis is ``what of the vacuum energy of those modes associated
with neither the extreme ultraviolet (where ordinary field theory
breaks down) nor the extreme infrared (where ordinary general
relativity is assumed to break down)?". After discussing an infrared
divergence which we find to be present in a larger class of powerlaw
spacetimes than has been previously found, we also implement an
infrared cutoff on energies. An interpretation of the infrared
cutoff as the realization of a local expansion of a patch of an
otherwise flat and very large `ambient' spacetime is attempted and
the corresponding picture of an energetic initiation of inflation is
provided.
The phenomenon of superoscillations for bandlimited functions is the
observation that a function may approximate to arbitrary precision a
plane wave not contained in it's Fourier decomposition. In
particular, it is possible for a function with compact support in
the frequency domain to approximate with arbitrary precision a high
frequency waveform outside of this support on an arbitrary long
interval. This phenomenon has only recently begun to be studied in
the literature and as yet very few quantitative results have been
obtained. In the second part of this thesis we study the energetic
response of a classical and quantum harmonic oscillator driven by a
superoscillating driving force. We find that the oscillator indeed
responds to the `imposter' driving force as if it were real and,
dubbing the response `ghost resonance', we investigate some
consequences in quantum field theory and cosmology.

85 
Vacuum Energy in Expanding Spacetime and Superoscillation  Induced ResonancePrain, Angus January 2008 (has links)
This thesis is divided into two parts. The first part is a study of
the general problem of vacuum energy or socalled `zero point
fluctuations' of a quantum field on expanding spacetimes and the
interplay between the dilution of energy as a mode expands and the
generation of energy as new modes enter from below the ultraviolet
cutoff. The second deals with the phenomenon of superoscillations
and some of the consequences in quantum theory and cosmology.
Modern theoretical cosmology sits upon the theory of inflation
which assumes that the universe underwent a period of accelerated
expansion sometime in the past. Indeed, a whole new scientific
discipline was born known as high precision observational cosmology
when ground breaking detailed measurements were made in the late
1990's that confirmed some predictions of the theory of inflation.
However, inflation is essentially a classical phenomenon with the
inclusion of the quantum theory relegated to the provision of
initial perturbations of an otherwise homogeneous and isotropic
spacetime usually interpreted as the inexorable quantum fluctuations
of a (classical) scalar field coupled to the metric.
Quantum field theory on curved spacetime, on the other hand, has
some novel features in comparison to it's flat spacetime cousin. The
inclusion of some of these effects into a discussion of the novel
inflationary picture should provide some very interesting and
nontrivial insights to the very early universe and perhaps might
shed some light on the fundamental nature of the gravitational
interaction itself. Usually when studying quantum fields in curved
spacetime and the energetic interaction between gravity and the
quanta one works in the semiclassical picture where gravity remains
a classical field. This is not only because a fully consistent
quantum theory of gravity has not been constructed yet. Indeed,
there should exist a presumably quite extensive regime where the
picture of quantum fields propagating on a classical background
remains a valid approximation. In the first part of this thesis we
study this regime and some of the interesting physics that arises.
Eventually, however, we go one step further than a semiclassical
treatment and investigate the hypothesis that the dynamics of
cosmologically significant spacetimes is provided by the spacetime
dependence of the quantum vacuum energy of a scalar field on
that spacetime. Put more simply, we discuss the possibility that the
tendency for a spacetime to expand and accelerate it's expansion
reduces to the statement that it is vacuumenergetically favorable
to do so. The idea that the gravitational degrees of freedom are
induced in this way is an old one due to Sakharov and is one
represented in this thesis in simplified form and with specific
calculations and examples. We find that such an interpretation is at
least not excluded and, in fact, sits satisfactorily with the ideas
of inflation.
Along the way to our conclusive discussion of the `induced
cosmology' we discuss, after briefly reviewing inflation and quantum
field theory in curved spacetime, the general problem of vacuum
energy in curved spacetime and some simplified models of the quantum
mechanical ground state energy of a collection of harmonic
oscillators on expanding spaces including some discrete models. Our
philosophy throughout will be one of pragmatism; we assume a cutoff
on momenta (or length scales) at an unspecified energy scale and
assume our conclusions hold, if not all the way from the Planck
scale (which would presumably be subject to beyond the standard
model `quantum gravitational' effects), then at least in some
mesoscale between the Hubble scale and the Planck scale. It is
certainly true that a quantum scalar field really is a collection of
independent harmonic oscillators one for each different comoving
length scale (wavelength). The question that we seek to address in
this thesis is ``what of the vacuum energy of those modes associated
with neither the extreme ultraviolet (where ordinary field theory
breaks down) nor the extreme infrared (where ordinary general
relativity is assumed to break down)?". After discussing an infrared
divergence which we find to be present in a larger class of powerlaw
spacetimes than has been previously found, we also implement an
infrared cutoff on energies. An interpretation of the infrared
cutoff as the realization of a local expansion of a patch of an
otherwise flat and very large `ambient' spacetime is attempted and
the corresponding picture of an energetic initiation of inflation is
provided.
The phenomenon of superoscillations for bandlimited functions is the
observation that a function may approximate to arbitrary precision a
plane wave not contained in it's Fourier decomposition. In
particular, it is possible for a function with compact support in
the frequency domain to approximate with arbitrary precision a high
frequency waveform outside of this support on an arbitrary long
interval. This phenomenon has only recently begun to be studied in
the literature and as yet very few quantitative results have been
obtained. In the second part of this thesis we study the energetic
response of a classical and quantum harmonic oscillator driven by a
superoscillating driving force. We find that the oscillator indeed
responds to the `imposter' driving force as if it were real and,
dubbing the response `ghost resonance', we investigate some
consequences in quantum field theory and cosmology.

86 
Characterization of Product Quality Attributes and Thermal Properties of Potato Chips during Vacuum FryingYagua Olivares, Carla Veronica 2010 August 1900 (has links)
Vacuum frying is an alternative processing method for producing high quality
snacks with the advantages of lower processing temperature, enhanced organoleptic
quality, and reduced acrylamide content. Vacuum frying (1.33 kPa), with the aid of a deoiling
mechanism, was used to produce lowfat potato chips.
The kinetics of oil absorption and oil distribution in the potato chips (total,
internal, and surface oil content) was studied so that effectiveness of the deoiling
system could be established. An analysis of product quality attributes (PQA) such as
moisture content, oil content, microstructure, diameter shrinkage, and thickness
expansion, as well as, bulk density, true density, and porosity of chips fried at different
temperatures (120, 130, and 140 degrees C) was performed in order to evaluate the effect of
process temperature on the product. Moreover, heat capacity of the chips and convective
heat transfer coefficient at the oilchip interface were determined for the same
temperature range.
The final oil content of the potato chips was 0.072±0.004, 0.062±0.003, and
0.059±0.003 g/g solid for frying temperatures of 120, 130, and 140 degrees C, respectively.
These values are lower (8085 percent less) than those found in traditionallyfried potato chip
which indicates that the deoiling mechanism is crucial in vacuum frying processing. A
significant difference (P<0.05) was observed in oil content and oil distribution within
temperatures. It was found that the rate of change in PQAs is greatly affected by
temperature; however, the final values of moisture content, bulk density, true density,
porosity, diameter shrinkage, and thickness expansion were not affected by temperature.
During vacuum frying, the specific heat of potato chips decreased with time as
water decreases. The convective heat transfer coefficient changed considerably as frying
progresses; moreover, it increased with temperature reaching a maximum between 2,200
and 2,650 W/m2K depending on frying temperature.

87 
1.Synthesis,Pyrolytic and Photolytic Study of Furo[3,2c] Pyran4one 2.Pyrolytic Study of Benzoic 1,2Dimethyl3Indoly AnhydrideHuang, ChiTsung 07 December 2004 (has links)
(1)Flash vaccum pyrolysis of furo[3,2c]pyran4one gave starting material, but in photolytic system we gave a isomer: furo[2,3c]pyran5one.
(2)Flash vaccum pyrolysis of benzoic 1,2dimethyl3indoly anhydride,via a ketene intermediate,gave a dimmer.

88 
Pyrolytic Study of 2Azidocycloheptanone and 2[2(4Methoxyphenyl)vinyl]benzofuranWu, BoJian 18 June 2005 (has links)
Flash vacuum pyrolysis (FVP) of 2azidocycloheptanone gave two products: 3,4,5,6tetrahydro1Hazocin2one and 1hydroxy2oxo4 azabicyclo[5.3.0]dec4ene3spiro2¡¦cycloheptanone.
Flash vacuum pyrolysis of 2[2(4methoxyphenyl)vinyl]benzofuran gave two products: 4(2benzofuran2ylvinyl)phenol and 1H6oxacyclopenta[c]fluorine.

89 
Pyrolytic Study of 1Azidoindene and 3(4Methoxystyryl)thiopheneHsueh, Yutan 30 August 2005 (has links)
Flash vacuum pyrolysis (FVP) of 1azidoindene, which via a nitrene intermediate, gave some products of rearrangement¡Gquinoline¡Bisoquinoline and 1methylene1Hisoindole¡CUnder pyrolytic conditions, 3(4methoxystyryl)thiophene could get a radical intermediate and gave 3(4hydroxystyryl)thiophene, or it gave contractive tricyclic compounds which having signals on spectrum but inseparable, like as indene structures.

90 
1. Pyrolytic Study of Arylmethylazides 2. Pyrolytic Study of 2Amino3methylpyridine and its DerivativesLee, ChinFan 27 June 2001 (has links)
Flash vacuum pyrolysis(FVP) of azidomethylthiophene,via a nitrene intermediate,gave two products,a dimer (thienylmethylidenethienylamine) and a trimer (N,N`dithienyl methylidenethienylmethylidene diamine).The trimer underwent cyclization and dehydrogenation to afford 2,4,5trithienylimidazole. However by the same route, FVP of azidomethylbenzo[b]furan produced only a trimer(dibenzo[b]furylmethylideneN,N'benzo[b]furylmethyl amine).

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