44 research outputs found
Large eddy simulations of turbulent channel flow based on interscale energy transfer
A previously developed modeling procedure for large eddy simulations (LESs)
is extended to allow physical space implementations for inhomogeneous flows.
The method is inspired by the well-established theoretical analyses and
numerical investigations of homogeneous, isotropic turbulence. A general
procedure that focuses on recovering the full subgrid scale (SGS) dissipation
from resolved fields is formulated, combining the advantages of both the
structural and the functional strategy of modeling. The interscale energy
transfer is obtained from the test-filtered velocity field, corresponding
subfilter scale (SFS) stress or, equivalently, the similarity model is used to
compute the total SGS dissipation. The energy transfer is then cast in the form
of eddy viscosity, allowing it to retain the desired total SGS dissipation and
making the method numerically robust as an automatic step of backscatter
control. The method is capable of providing a proper amount of total energy
dissipation in actual, low resolution LES runs. The new approach is general and
self-contained, working well for different filtering kernels, Reynolds numbers,
and grid resolutions
Coherently coupled photonic-crystal surface-emitting laser array
The realization of a 1 × 2 coherently coupled photonic crystal surface emitting laser array is reported. New routes to power scaling are discussed and the electronic control of coherence is demonstrated
1.5 {\mu}m Epitaxially Regrown Photonic Crystal Surface Emitting Laser Diode
We present an InP-based epitaxially regrown photonic crystal surface emitting
laser diode, lasing in quasi- CW conditions at 1523nm.Comment: 4 pages, 5 figures, journal submission for revie
Concept for a Future Super Proton-Proton Collider
Following the discovery of the Higgs boson at LHC, new large colliders are
being studied by the international high-energy community to explore Higgs
physics in detail and new physics beyond the Standard Model. In China, a
two-stage circular collider project CEPC-SPPC is proposed, with the first stage
CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on
Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused
on new physics beyond the Standard Model. This paper discusses this second
stage.Comment: 34 pages, 8 figures, 5 table
Identification of Genes Directly Involved in Shell Formation and Their Functions in Pearl Oyster, Pinctada fucata
Mollusk shell formation is a fascinating aspect of biomineralization research. Shell matrix proteins play crucial roles in the control of calcium carbonate crystallization during shell formation in the pearl oyster, Pinctada fucata. Characterization of biomineralization-related genes during larval development could enhance our understanding of shell formation. Genes involved in shell biomineralization were isolated by constructing three suppression subtractive hybridization (SSH) libraries that represented genes expressed at key points during larval shell formation. A total of 2,923 ESTs from these libraries were sequenced and gave 990 unigenes. Unigenes coding for secreted proteins and proteins with tandem-arranged repeat units were screened in the three SSH libraries. A set of sequences coding for genes involved in shell formation was obtained. RT-PCR and in situ hybridization assays were carried out on five genes to investigate their spatial expression in several tissues, especially the mantle tissue. They all showed a different expression pattern from known biomineralization-related genes. Inhibition of the five genes by RNA interference resulted in different defects of the nacreous layer, indicating that they all were involved in aragonite crystallization. Intriguingly, one gene (UD_Cluster94.seq.Singlet1) was restricted to the ‘aragonitic line’. The current data has yielded for the first time, to our knowledge, a suite of biomineralization-related genes active during the developmental stages of P.fucata, five of which were responsible for nacreous layer formation. This provides a useful starting point for isolating new genes involved in shell formation. The effects of genes on the formation of the ‘aragonitic line’, and other areas of the nacreous layer, suggests a different control mechanism for aragonite crystallization initiation from that of mature aragonite growth
Strategy for TSV scaling with consideration on thermo-mechanical stress and acceptable delay
Based on the 2011 ITRS road map, the greater accessibility of higher number of TSVs in a specified area depends on the smarter miniaturization of the interconnect dimension in 3D IC packaging. Scaling down the TSV dimension has an inevitable effect on resistance, capacitance, signal transmission as well as the thermo-mechanical stress. We report that the lowering of the TSV diameter is permissible under thermo-mechanical stress consideration. However, the signal transmission delay explodes rapidly and could be tunable via controlling the liner layer capacitance or/and using alternative filler materials