140 research outputs found
Spray-assisted assembly of thin-film composite membranes in one process
Spray coating has been exploited to fabricate and tailor the morphologies of various components in thin film composite membranes separately. For the first time, here we exploit this technology to construct and assemble both the selective layer and porous support of a thin-film composite membrane in a single process. In our approach, spray-assisted non-solvent induced phase inversion and interfacial polymerization reduced the time required to fabricate thin-film composite membranes from 3 – 4 days to 1 day and 40 mins. Our approach did not sacrifice membrane separation performances during desalination of a mixture comprising 2000 ppm of NaCl in water at 4 bar and room temperature. At these conditions, compared to traditional thin film composite membranes, the water permeance of our spray coated membranes was higher by 35.7 %, reaching 2.32 L m-2 h-1 bar-1, while achieving a NaCl rejection rate of 94.7 %. This demonstrated the feasibility of fabricating thin film composites via spray coating in a single process, potentially reducing fabrication time during scale-up production
Leakage Analysis and Solution of the RFID Analog Front-END
The identification and modeling of different leakage components are very important for estimation and reduction of leakage power, especially low-power applications, such as RFID chip. This paper proposes a theory about leakage mechanism of RFID chip and proves the theory. The one contribution of the paper is the proposed theory about leakage mechanism of RFID chip. The other contribution is that it proves the differences between tape-out verification results and computer simulation results and that to what degree the differences occur for different circuits. And when the source potential is much lower than the substrate potential, tape-out verification results and computer simulation results have larger differences. The test results show that the actual leakage power increases 26.3 times compares with the computer simulation results’ when the source potential is -750mV
Interfacial polymerization using biobased solvents and their application as desalination and organic solvent nanofiltration membranes
First-order magnetic and structural phase transitions in FeSeTe
We use bulk magnetic susceptibility, electronic specific heat, and neutron
scattering to study structural and magnetic phase transitions in FeSe%
Te. FeTe exhibits a first order phase transition near 67
K with a tetragonal to monoclinic structural transition and simultaneously
develops a collinear antiferromagnetic (AF) order responsible for the entropy
change across the transition. Systematic studies of FeSeTe system
reveal that the AF structure and lattice distortion in these materials are
different from those of FeAs-based pnictides. These results call into question
the conclusions of present density functional calculations, where
FeSeTe and FeAs-based pnictides are expected to have similar Fermi
surfaces and therefore the same spin-density-wave AF order.Comment: 5 pages, 3 figure
Tracking the nematicity in cuprate superconductors: a resistivity study under uniaxial pressure
Overshadowing the superconducting dome in hole-doped cuprates, the pseudogap
state is still one of the mysteries that no consensus can be achieved. It has
been suggested that the rotational symmetry is broken in this state and may
result in a nematic phase transition, whose temperature seems to coincide with
the onset temperature of the pseudogap state around optimal doping level,
raising the question whether the pseudogap results from the establishment of
the nematic order. Here we report results of resistivity measurements under
uniaxial pressure on several hole-doped cuprates, where the normalized slope of
the elastoresistivity can be obtained as illustrated in iron-based
superconductors. The temperature dependence of along particular lattice
axis exhibits kink feature at and shows Curie-Weiss-like behavior above
it, which may suggest a spontaneous nematic transition. While seems to
be the same as around the optimal doping and in the overdoped region,
they become very different in underdoped LaSrCuO. Our results
suggest that the nematic order, if indeed existing, is an electronic phase
within the pseudogap state.Comment: 6 pages, 4 figure
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