This Letter reports the novel use of poly(9‐vinylcarbazole) (PVK) as a dielectric interfacial layer for n‐type organic field‐effect transistors (n‐OFETs). With PVK, both the air stability and electron mobility of N,N′‐ditridecylperylene‐3,4,9,10‐tetracarboxylic diimide (PTCDI‐C13)‐based OFETs were improved. Among the PVKs with different weight‐average molecular weight (Mw), PVK with high Mw showed good performance. The high glass transition temperature of PVK enabled thermal post annealing of the active layer, which resulted in a high electron mobility of 0.61 cm2/Vs. This mobility was maintained at 90% and 59% after 4 days and 105 days in air, respectively. The PVK interfacial layer reduced the trapped charges in the PTCDI‐C13‐based n‐OFET for air‐exposure and caused a decrease in the threshold voltage shift.
We present an in-medium modified pion and rho meson Lagrangian which describes the pion, rho meson and the corresponding soliton properties in nuclear matter. Within the present approach pion properties in nuclear matter is closely related to the low-energy pion-nucleus scattering phenomenology. We discuss the possible modifications of rho meson properties in nuclear matter. 相似文献
Recently, LEPS collaboration reported the parity spin asymmetry for the γp → K*0Σ+ reaction using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. The parity spin asymmetry (${P_{\sigma} = 2\rho^{1}_{1-1} - \rho^{1}_{00}}$) was obtained, with large positive asymmetry at forward angles. This supports that natural-parity exchange is dominant at forward angles for K*0Σ+ photoproduction, which is consistent with κ meson-exchange. The differential cross sections for the γp → K*0Σ+ reaction are presented at forward angles averaged over all beam energies. There is good agreement with the differential cross sections from the CLAS and the CBELSA/TAPS collaborations. 相似文献
Let R be a commutative ring with identity and S a multiplicative subset of R. We say that R is an S-Noetherian ring if for each ideal I of R, there exist an s ∈ S and a finitely generated ideal J of R such that sI ? J ? I. In this article, we study transfers of S-Noetherian property to the composite semigroup ring and the composite generalized power series ring. 相似文献
We investigate a configurationally locked polyene (CLP) crystal 2‐(3‐(4‐hydroxystyryl)‐5,5‐dimethylcyclohex‐2‐enylidene)malononitrile (OH1) containing a phenolic electron donor, which also acts as a hydrogen bond donor. The OH1 crystals with orthorhombic space group Pna21 (point group mm2) exhibit large second‐order nonlinear optical figures of merit, high thermal stability and very favorable crystal growth characteristics. Higher solubility in methanol and a larger temperature difference between the melting temperature and the decomposition temperature of OH1 compared to analogous CLP crystals, are of advantage for solution and melt crystal growth, respectively. Acentric bulk OH1 crystals of large sizes with side lengths of up to 1 cm with excellent optical quality have been successfully grown from methanol solution. The microscopic and macroscopic nonlinearities of the OH1 crystals are investigated theoretically and experimentally. The OH1 crystals exhibit a large macroscopic nonlinearity with four times larger powder second harmonic generation efficiency than that of analogous CLP crystals containing dimethylamino electron donor. A very high potential of OH1 crystals for broadband THz wave emitters in the full frequency range of 0.1–3 THz by optical rectification of 160 fs pulses has been demonstrated. 相似文献
Anodic dissolution characteristics and electrochemical migration (ECM) behavior of Sn-3.0Ag-0.5Cu solder in NaCl and Na2SO4 solutions were investigated using anodic polarization tests and water drop tests (WDT). The ECM lifetime of Sn-3.0Ag-0.5Cu
solder in NaCl solution (42.4 s) was longer than that in Na2SO4 solution (34.8 s). The pitting potential of Sn-3.0Ag-0.5Cu solder in NaCl solution (135 mV, SCE) was higher than that in
Na2SO4 solution (−367 mV, SCE). The passivity film (SnO2) formed on Sn-3.0Ag-0.5Cu solder during WDTs in NaCl solution was thicker than that formed in Na2SO4 solution. Therefore, the longer ECM lifetime of Sn-3.0Ag-0.5Cu solder in NaCl solution than in Na2SO4 solution can be attributed to the higher pitting potential in the NaCl solution, which is ascribed to the formation of a
thicker passivity film (SnO2) in the former. It was confirmed that microelements such as Ag and Cu do not take part in ECM because they form chemically
stable intermetallic compounds with Sn. We believe that Sn is the only element that contributes to ECM, and dissolution of
Sn at the anode is possibly the rate-determining step of ECM of Sn-3.0Ag-0.5Cu solder. 相似文献
Ultrasonic bonding of Si-dice to type FR-4 printed circuit boards (PCB) with Sn-3.5wt.%Ag solder at ambient temperature was
investigated. The under-bump metallization (UBM) on the Si-dice comprised Cu/Ni/Al from top to bottom with thicknesses of
0.4 μm, 0.4 μm, and 0.3 μm, respectively. The pads on the PCBs consisted of Au/Ni/Cu with thicknesses of 0.05/5/18 μm, sequentially from top to bottom. Solder was supplied as Sn-3.5wt.%Ag foil rolled to 100 μm thickness, and inserted in the joints. The ultrasonic bonding time was varied from 0.5 s to 3.0 s, and the ultrasonic power
was 1400 W. The experimental results showed that reliable joints could be produced between the Si-dice and the PCBs with Sn-3.5wt.%Ag
solder. The joint breaking force of “Si-die/solder/FR-4” increased with bonding times up to 2.5 s with a maximum value of
65 N. A bonding time of 3.0 s proved to be excessive, and resulted in cracks along the intermetallic compound between the
UBM and solder, which caused a decrease in the bond strength. The intermetallic compound produced by ultrasonic bonding between
the UBM and solder was confirmed to be (Cu, Ni)6Sn5.
An erratum to this article can be found at 相似文献
This paper presents a new methodology of automatic RTL code generation from coarse-grain dataflow specification for fast HW/SW
cosynthesis. A node in a coarse-grain dataflow specification represents a functional block such as FIR and DCT and an arc
may deliver multiple data samples per block invocation, which complicates the problem and distinguishes it from behavioral
synthesis problem. Given optimized HW library blocks for dataflow nodes, we aim to generate the RTL codes for the entire hardware
system including glue logics such as buffer and MUX, and the central controller. In the proposed design methodology, a dataflow
graph can be mapped to various hardware structures by changing the resource allocation and schedule information. It simplifies
the management of the area/performance tradeoff in hardware design and widens the design space of hardware implementation
of a dataflow graph. We also support Fractional Rate Dataflow (FRDF) specification for more efficient hardware implementation.
To overcome the additional hardware area overhead in the synthesized architecture, we propose two techniques reducing buffer
overhead. Through experiments with some real examples, the usefulness of the proposed technique is demonstrated.