30,051 research outputs found
Dr. Yang Zhong: an explorer on the road forever
On the morning of September 25th 2017, grievous news spread from the remote Ordos region of Inner Mongolia to Fudan University campus in Shanghai. Professor Yang Zhong, a famous botanist and the Dean of Fudan University’s graduate school, passed away in a tragic car accident while on a business trip
Beam energy dependence of Hanbury-Brown-Twiss radii from a blast-wave model
The beam energy dependence of correlation lengths (the Hanbury-Brown-Twiss
radii) is calculated by using a blast-wave model and the results are comparable
with those from RHIC-STAR beam energy scan data as well as the LHC-ALICE
measurements. A set of parameter for the blast-wave model as a function of beam
energy under study are obtained by fit to the HBT radii at each energy point.
The transverse momentum dependence of HBT radii is presented with the extracted
parameters for Au + Au collision at 200 GeV and for Pb+Pb
collisions at 2.76 TeV. From our study one can learn that particle emission
duration can not be ignored while calculating the HBT radii with the same
parameters. And tuning kinetic freeze-out temperature in a range will result in
system lifetime changing in the reverse direction as it is found in RHIC-STAR
experiment measurements.Comment: 9 pages, 9 figure
Refinement and growth enhancement of Al2Cu phase during magnetic field assisting directional solidification of hypereutectic Al-Cu alloy.
International audienceUnderstanding how the magnetic fields affect the formation of reinforced phase during solidification is crucial to tailor the structure and therefor the performance of metal matrix in situ composites. In this study, a hypereutectic Al-40 wt.% Cu alloy has been directionally solidified under various axial magnetic fields and the morphology of Al2Cu phase was quantified in 3D by means of high resolution synchrotron X-ray tomography. With rising magnetic fields, both increase of Al2Cu phase's total volume and decrease of each column's transverse section area were found. These results respectively indicate the growth enhancement and refinement of the primary Al2Cu phase in the magnetic field assisting directional solidification. The thermoelectric magnetic forces (TEMF) causing torque and dislocation multiplication in the faceted primary phases were thought dedicate to respectively the refinement and growth enhancement. To verify this, a real structure based 3D simulation of TEMF in Al2Cu column was carried out, and the dislocations in the Al2Cu phase obtained without and with a 10T high magnetic field were analysed by the transmission electron microscope
Electrogasdynamic Spectral Anemometer
PatentAn electrogasdynamic spectral anemometer including
a particle injector and a particle collector that are inserted
into a turbulent fluid stream that is under investigation.
The injector includes a hollow cylinder into
which near saturated steam from an outside source is
introduced. The injector also includes a nozzle, a corona
needle and an attractor ring which are oppositely
charged and located within the nozzle. As the steam
passes through the nozzle it supersaturates and condenses
into droplets having a size that is primarily determined
by the condition of the incoming steam. The
droplets are then charged through the corona developed
between the corona needle and the attractor
ring. Then the charged droplets are ejected from the
nozzle and into the stream to be measured where they
follow its rapid fluctuations. These charged particles
move towards the collector which may be placed
downstream of the injector. When a charged particle
passes the collector it becomes neutralized and transmits
an electrical signal into collector circuitry where
it is analyzed to provide information about the intensity
of the turbulence at various frequencies. Different
droplet sizes are used for different turbulent frequencies
of interest depending on the maximum value of
the frequency present in the flow
Altered nerve terminal arborization and synaptic transmission in Drosophila mutants of cell adhesion molecule fasciclin I
This work investigates the role of cell adhesion molecules in development of synaptic connections and functions through a genetic approach. Fasciclin I (Fas I) is an insect glycoprotein capable of mediating homophilic cell adhesion. It has been shown that Fas I is expressed in motor nerve axons and terminals that innervate larval body-wall muscles in Drosophila. Immunohistochemical analysis of these motor nerve terminals has revealed that nerve terminal arborization, quantified by the numbers of the nerve terminal branches and varicosities, is enhanced in the null mutant fas ITE. In contrast, the number of branches and varicosities are reduced in larvae that overexpress the Fas I molecule resulting from additional copies of the fas I transgene in P(fas I+) or the chromosome duplication in Dp(fas I) mutants. Although arborization is altered, the overall stereotypical pattern of nerve terminal innervation of the body-wall muscle fibers is preserved in all the Fas I mutants examined. The voltage-clamp analysis of excitatory junctional currents (ejcs) at the neuromuscular junction indicates that the amplitude of ejcs is reduced in fas ITE, but increased in P(fas I+) and Dp(fas I) compared to that in wild-type larvae. Further electrophysiological analysis shows that the quantal content and the evoked frequency-dependent response are affected in these mutants, indicating a defective presynaptic function in addition to the anatomic abnormality. Therefore, the cell adhesion molecule Fas I may not be essential for target recognition and synaptogenesis at the larval neuromuscular junction, but may play a role in fine-turning nerve terminal arborization and possibly in modifying, directly or indirectly, development of presynaptic functions
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