402 research outputs found
Study on Thermal Stress of Honeycomb Ceramic Regenerators with Different Parameters
In thermal flow-reversal reactor operations, honeycomb
ceramic regenerators are exposed to
thermal shock load. In this study, numerical simulations
of the temperature and thermal stress
distributions of honeycomb ceramic regenerators
are carried out using the CFX software.
Temperature variations with time are calculated
first for honeycomb ceramic regenerators with
holes of different shapes. Then, thermal stress
distributions of regenerators are analyzed with
different structural and operational parameters.
The analyses show that the thermal stress of honeycomb
ceramic regenerator depends on the
shape of holes, porosity and wall thicknesses.
This study provides a theoretical basis for optimization
of honeycomb ceramic regenerators.При работе ядерного реверс-поточного реактора керамические сотовые регенераторы подвергаются действию термоударной нагрузки. С помощью программного обеспечения CFX
проведено численное моделирование эпюр температуры и температурного напряжения керамических сотовых регенераторов. Исследовано изменение температур во времени для керамических сотовых регенераторов с отверстиями различной формы. Проанализированы
эпюры температурного напряжения регенераторов с разными конструкционными и эксплуатационными параметрами. Установлено, что температурное напряжение керамического
сотового регенератора зависит от формы отверстий, пористости и толщины стенок.
Результаты данного исследования служат теоретической базой для оптимизации керамических сотовых регенераторов.При роботі ядерного реверс-потокового реактора керамічні стільникові регенератори
зазнають дії термоударного навантаження. За допомогою програмного забезпечення
СFX проведено чисельне моделювання епюр температури і температурного напруження керамічних стільникових регенераторів. Досліджено зміну температур у часі
для керамічних стільникових регенераторів з отворами різної форми. Проаналізовано епюри температурного напруження регенераторів із різними конструкційними експлуатаційними параметрами. Установлено, що температурне напруження керамічного стільникового регенератора залежить від форми отвору, пористості і товщини стінок. Результати даного дослідження є теоретичною базою для оптимізації
керамічних стільникових регенераторів
Improved performance robustness of DSP-enabled flexible ROADMs free from optical filters and O-E-O conversions
Utilizing Hilbert-pair-based digital filtering, intensity modulation, and passive optical coupling, digital signal processing (DSP) enabled flexible reconfigurable optical add/drop multiplexers (ROADMs) are reported, which are free from optical filters and optical-electrical-optical (O-E-O) conversions and offer excellent flexibility, color-lessness, gridlessness, contentionlessness, adaptability, and transparency to physical-layer network characteristics. In this paper, the ROADM performance robustness against variations in numerous network design aspects is, for the first time to the best of our knowledge, extensively explored in intensity-modulation- and direct-detection-based optical network nodes. Numerical results show that DSPs not only enable the ROADMs to dynamically and flexibly perform add/drop operations at wavelength, subwavelength, and spectrally overlapped orthogonal subband levels but also considerably improve the ROADM performance robustness against variations in modulation formats, transmission system characteristics/impairments, and terminal equipment configurations
On Vanishing Theorems For Vector Bundle Valued p-Forms And Their Applications
Let be a strictly increasing function
with . We unify the concepts of -harmonic maps, minimal
hypersurfaces, maximal spacelike hypersurfaces, and Yang-Mills Fields, and
introduce -Yang-Mills fields, -degree, -lower degree, and generalized
Yang-Mills-Born-Infeld fields (with the plus sign or with the minus sign) on
manifolds. When and
the -Yang-Mills field becomes an ordinary Yang-Mills field,
-Yang-Mills field, a generalized Yang-Mills-Born-Infeld field with the plus
sign, and a generalized Yang-Mills-Born-Infeld field with the minus sign on a
manifold respectively. We also introduce the energy functional (resp.
-Yang-Mills functional) and derive the first variational formula of the
energy functional (resp. -Yang-Mills functional) with
applications. In a more general frame, we use a unified method to study the
stress-energy tensors that arise from calculating the rate of change of various
functionals when the metric of the domain or base manifold is changed. These
stress-energy tensors, linked to -conservation laws yield monotonicity
formulae. A "macroscopic" version of these monotonicity inequalities enables us
to derive some Liouville type results and vanishing theorems for forms with
values in vector bundles, and to investigate constant Dirichlet boundary value
problems for 1-forms. In particular, we obtain Liouville theorems for
harmonic maps (e.g. -harmonic maps), and Yang-Mills fields (e.g.
generalized Yang-Mills-Born-Infeld fields on manifolds). We also obtain
generalized Chern type results for constant mean curvature type equations for
forms on and on manifolds with the global doubling property
by a different approach. The case and is due to Chern.Comment: 1. This is a revised version with several new sections and an
appendix that will appear in Communications in Mathematical Physics. 2. A
"microscopic" approach to some of these monotonicity formulae leads to
celebrated blow-up techniques and regularity theory in geometric measure
theory. 3. Our unique solution of the Dirichlet problems generalizes the work
of Karcher and Wood on harmonic map
Study of J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar
The branching ratios and Angular distributions for J/psi decays to Lambda
Lambdabar and Sigma0 Sigma0bar are measured using BESII 58 million J/psi.Comment: 11 pages, 5 figure
Measurements of the observed cross sections for exclusive light hadron production in e^+e^- annihilation at \sqrt{s}= 3.773 and 3.650 GeV
By analyzing the data sets of 17.3 pb taken at GeV
and 6.5 pb taken at GeV with the BESII detector at the
BEPC collider, we have measured the observed cross sections for 12 exclusive
light hadron final states produced in annihilation at the two energy
points. We have also set the upper limits on the observed cross sections and
the branching fractions for decay to these final states at 90%
C.L.Comment: 8 pages, 5 figur
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
Study of
New data are presented on from a sample of 58M
events in the upgraded BES II detector at the BEPC. There is a
conspicuous signal for and a peak at higher mass which
may be fitted with . From a combined analysis with
data, the branching ratio
is at the 95%
confidence level.Comment: 11 pages, 5 figures. Submitted to Phys. Lett.
Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-
We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi -->
D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7
J/Psi events collected with the BESII detector at the BEPC. No excess of signal
above background is observed, and 90% confidence level upper limits on the
branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi
--> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
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