503 research outputs found
Using quantile regression to evaluate human thermal climates in China: Working paper series--08-09
Studies have been conducted to examine the spatial variations of human thermal comfort in various countries using different comfort indices. These human thermal climate studies have important implications on human health, migration patterns, retirement decisions, tourism development and energy requirements. Yan (2005) used a clothing insulation (CLO) index to construct average clothing needs in various regions of China. These average CLO maps, however, only provided information on the center of the distribution of climate variation. Using quantile regressions, we estimated index and constructed contour maps for the whole spectrum of the CLO distribution to provide additional information on the spread and variation of the clothing requirements and, hence, a more complete picture of the human comfort of the various regions in China
A Biomimetic Smart Control of Viscous Drag Reduction
Viscous flow drag represents the largest contingent of the entire drag that aerodynamic and hydrodynamic devices are subject to. Inspired by the functions of sharks skins, riblet surfaces have been studied and applied to wall structures to reduce turbulent flow drag. However, whilst structural similarity has been obtained it lacks true mimicry. This paper presents an approach of drag reduction using “Smart Surface”, a new propose composite surface that combines the riblet with an elastic coating. The “smart surface”, inspired by the self-adjustable skin of marine animals such as the dolphin, is designed to modify the traditional riblet technique and enable it to “sense” and interact with the flow by adjusting the wall structure according to the flow condition. Considering the factors of manufacture feasibility, durability and drag reduction performance in previous studies, the physical model of “Smart Surface” is designed. The preliminary establishment of corresponding prediction model has been discussed and calculated. Further work in the aspects of experimental and numerical study of this research is prospected. Key words: Drag reduction; Elastic coating; Riblet; Self-adjustable; Smart Surfac
A modified phase change pseudopotential lattice Boltzmann model
Amongst all the multiphase models in the lattice Boltzmann (LB) community, the pseudopotential model has been the most popular approach due to its simplicity and high-efficiency. Recently a number of liquid-vapour phase change models were also proposed based on the pseudopotential LB model. Our study finds that most of the published pseudopotential phase change models rely on an entropy-based energy equation, while the entropy-based energy equation is derived with the equation of state of ideal gas. That means this entropy-based energy equation is not completely suitable for multiphase ow which applies non-ideal equation of state for the phase separation simulation. Therefore a new phase change LB model is proposed in this work, where an improved pseudopotential multiphase model (Li et al., 2013) and a modified energy equation which is solved in the classical fourth-order Runge-Kutta scheme are coupled in a hybrid scheme. The results show that the numerical simulation can capture the basic liquid-vapour phase change features. The D2 law for droplet evaporation is validated and the square of diameter variation is in good agreement with experimental data. Moreover, the three boiling stages (nucleate boiling, transition boiling and film boiling) are accomplished using the modified model, and the corresponding transient heat fluxes are presented
A simple lattice Boltzmann model for conjugate heat transfer research
In this paper a lattice Boltzmann (LB) model is proposed for conjugated heat transfer research. Through taking the most advantages of the standard LB method, the present model can remedy the shortcomings of the available related LB models via a simple way and meanwhile a number of intrinsic advantages of the standard LB method are preserved. It does not require any specific treatment dependent on interface topology and independent from the choice of lattice model. Moreover, it can be used for unsteady problems with complicated and time dependent interfaces. The accuracy and reliability of the present model are validated by three nontrivial benchmark tests. The good agreements between the present numerical prediction and available open data demonstrate the applicability of the present model for complicated conjugated heat transfer problems. Finally, the present model could be extended to some other important areas straightforwardly, such as fluid–solid phase change modeling
Finished sequence and assembly of the DUF1220-rich 1q21 region using a haploid human genome
BackgroundAlthough the reference human genome sequence was declared finished in 2003, some regions of the genome remain incomplete due to their complex architecture. One such region, 1q21.1-q21.2, is of increasing interest due to its relevance to human disease and evolution. Elucidation of the exact variants behind these associations has been hampered by the repetitive nature of the region and its incomplete assembly. This region also contains 238 of the 270 human DUF1220 protein domains, which are implicated in human brain evolution and neurodevelopment. Additionally, examinations of this protein domain have been challenging due to the incomplete 1q21 build. To address these problems, a single-haplotype hydatidiform mole BAC library (CHORI-17) was used to produce the first complete sequence of the 1q21.1-q21.2 region.ResultsWe found and addressed several inaccuracies in the GRCh37sequence of the 1q21 region on large and small scales, including genomic rearrangements and inversions, and incorrect gene copy number estimates and assemblies. The DUF1220-encoding NBPF genes required the most corrections, with 3 genes removed, 2 genes reassigned to the 1p11.2 region, 8 genes requiring assembly corrections for DUF1220 domains (~91 DUF1220 domains were misassigned), and multiple instances of nucleotide changes that reassigned the domain to a different DUF1220 subtype. These corrections resulted in an overall increase in DUF1220 copy number, yielding a haploid total of 289 copies. Approximately 20 of these new DUF1220 copies were the result of a segmental duplication from 1q21.2 to 1p11.2 that included two NBPF genes. Interestingly, this duplication may have been the catalyst for the evolutionarily important human lineage-specific chromosome 1 pericentric inversion.ConclusionsThrough the hydatidiform mole genome sequencing effort, the 1q21.1-q21.2 region is complete and misassemblies involving inter- and intra-region duplications have been resolved. The availability of this single haploid sequence path will aid in the investigation of many genetic diseases linked to 1q21, including several associated with DUF1220 copy number variations. Finally, the corrected sequence identified a recent segmental duplication that added 20 additional DUF1220 copies to the human genome, and may have facilitated the chromosome 1 pericentric inversion that is among the most notable human-specific genomic landmarks
Nonfactorizable contributions in B decays to charmonium: the case of
Nonleptonic to charmonium decays generally show deviations from the
factorization predictions. For example, the mode has
been experimentally observed with sizeable branching fraction while its
factorized amplitude vanishes. We investigate the role of rescattering effects
mediated by intermediate charmed meson production in this class of decay modes,
and consider with the meson.
Using an effective lagrangian describing interactions of pairs of heavy-light
mesons with a quarkonium state, we relate this mode to the
analogous mode with in the final state. We find large enough to be measured at the factories, so that this decay
mode could be used to study the poorly known .Comment: RevTex, 16 pages, 2 eps figure
Exact multilocal renormalization on the effective action : application to the random sine Gordon model statics and non-equilibrium dynamics
We extend the exact multilocal renormalization group (RG) method to study the
flow of the effective action functional. This important physical quantity
satisfies an exact RG equation which is then expanded in multilocal components.
Integrating the nonlocal parts yields a closed exact RG equation for the local
part, to a given order in the local part. The method is illustrated on the O(N)
model by straightforwardly recovering the exponent and scaling
functions. Then it is applied to study the glass phase of the Cardy-Ostlund,
random phase sine Gordon model near the glass transition temperature. The
static correlations and equilibrium dynamical exponent are recovered and
several new results are obtained. The equilibrium two-point scaling functions
are obtained. The nonequilibrium, finite momentum, two-time response and
correlations are computed. They are shown to exhibit scaling forms,
characterized by novel exponents , as well as
universal scaling functions that we compute. The fluctuation dissipation ratio
is found to be non trivial and of the form . Analogies and
differences with pure critical models are discussed.Comment: 33 pages, RevTe
Partial Wave Analysis of
BES data on are presented. The
contribution peaks strongly near threshold. It is fitted with a
broad resonance with mass MeV, width MeV. A broad resonance peaking at 2020 MeV is also required
with width MeV. There is further evidence for a component
peaking at 2.55 GeV. The non- contribution is close to phase
space; it peaks at 2.6 GeV and is very different from .Comment: 15 pages, 6 figures, 1 table, Submitted to PL
Hydrogen bond activated glycosylation under mild conditions
Herein, we report a new glycosylation system for the highly efficient and stereoselective formation of glycosidic bonds using glycosyl N-phenyl trifluoroacetimidate (PTFAI) donors and a charged thiourea hydrogen-bond-donor catalyst. The glycosylation protocol features broad substrate scope, controllable stereoselectivity, good to excellent yields and exceptionally mild catalysis conditions. Benefitting from the mild reaction conditions, this new hydrogen bond-mediated glycosylation system in combination with a hydrogen bond-mediated aglycon delivery system provides a reliable method for the synthesis of challenging phenolic glycosides. In addition, a chemoselective glycosylation procedure was developed using different imidate donors (trichloroacetimidates, N-phenyl trifluoroacetimidates, N-4-nitrophenyl trifluoroacetimidates, benzoxazolyl imidates and 6-nitro-benzothiazolyl imidates) and it was applied for a trisaccharide synthesis through a novel one-pot single catalyst strategy.Bio-organic Synthesi
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
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