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41.
The relaxation time τ of the polarization fluctuation is obtained from the frequency dependence of the sound velocity in MHz region. The value of τ is the order of 10 nsec just below the phase transition point and agrees with that obtained from the dispersion of the dielectric constant.  相似文献   
42.
The simultaneous diffusion of 14C-succinylcholine and p-amino hippurate across human placental tissue in vitro was measured. Column chromatographic purification of the radioactivity followed by paper chromatographic analysis showed little alteration of the succinylcholine during the course of these experiments. Similar chloroform-buffer partition coefficients for the two solutes were measured. Thus in these experiments, the nearly identical transfer rates of these two similar sized, lipid-insoluble compounds indicated that succinylcholine crosses human placental tissue in quantitites compatible with its molecular size and lipophobic nature, and that the diffusion rate is not significantly influenced by its increased molecular charge.  相似文献   
43.
Qi ZM  Honma I  Zhou H 《Analytical chemistry》2006,78(4):1034-1041
Chemical gas sensors that employ integrated optical polarimetric interferometry were fabricated by the sol-gel synthesis of transparent mesoporous thin films of TiO2-P2O5 nanocomposite on tapered layers of TiO2 sputtered on tin-diffused glass waveguides. Atomic force microscopy images of the mesoporous thin film clearly show the open pore mouths on the film surface that favor rapid diffusion and adsorption of gas-phase analytes within the entire film. Adsorption of gas and vapor induces changes (Deltan) in the refractive index of the mesoporous thin film that lead to shifts in the phase difference between the fundamental transverse electric and magnetic modes simultaneously excited in the glass waveguide via single-beam incidence. Upon exposure to NH3 gas at concentrations as low as 100 ppb in dry air at room temperature, the sensor exhibits a reversible change in the phase difference with the response and recovery times of less than 60 and 90 s, respectively. It is unexpected that the sensor is unresponsive to either NO2 or C6H6 vapor, leading to a somewhat selective sensitivity to NH3. Determination of Deltan was carried out with a combination of the experimental results and the theoretical calculations. The sensor design represents a novel, effective, and easily accessible approach to mesoporous thin-film-based integrated optical chemical sensors.  相似文献   
44.
The influence of crystal thickness of metal-coated <100>-cut GaAs (M-G-M) on Cherenkov-phase-matched terahertz (THz) pulse detection was studied. The M-G-M detectors were utilized in conjunction with a metallic tapered parallel-plate waveguide (TPPWG). Polarization-sensitive measurements were carried out to exemplify the efficacy of GaAs in detecting transverse magnetic (TM)- and transverse electric (TE)-polarized THz waves. The reduction of GaAs’ thickness increased the THz amplitude spectra of the detected TM-polarized THz electro-optic (EO) signal due to enhanced electric field associated with a more tightly-focused and well-concentrated THz radiation on the thinner M-G-M. The higher-fluence THz beam coupled to the thinner M-G-M improved the integrated intensity of the detected THz amplitude spectrum. This trend was not observed for TE-polarized THz waves, wherein the integrated intensities were almost comparable. Nevertheless, good agreement of spectral line shapes of the superposed TM- and TE-polarized THz-EO signals with that of elliptically polarized THz-EO signal demonstrates excellent polarization-resolved detection capabilities of M-G-M via Cherenkov-phase-matched EO sampling technique.  相似文献   
45.
Flexible and stretchable organic photovoltaics (OPVs) are promising as a power source for wearable devices with multifunctions ranging from sensing to locomotion. Achieving mechanical robustness and high power conversion efficiency for ultraflexible OPVs is essential for their successful application. However, it is challenging to simultaneously achieve these features by the difficulty to maintain stable performance under a microscale bending radius. Ultraflexible OPVs are proposed by employing a novel metal‐oxide‐free cathode that consists of a printed ultrathin metallic transparent electrode and an organic electron transport layer to achieve high electron‐collecting capabilities and mechanical robustness. In fact, the proposed ultraflexible OPV achieves a power conversion efficiency of 9.7% and durability with 74% efficiency retention after 500 cycles of deformation at 37% compression through buckling. The proposed approach can be applied to active layers with different morphologies, thus suggesting its universality and potential for high‐performance ultraflexible OPV devices.  相似文献   
46.
Mechanically durable transparent electrodes are needed in flexible optoelectronic devices to realize their long‐term stable functioning, for applications in various fields such as energy, healthcare, and soft robotics. Several promising transparent electrodes based on nanomaterials have been previously reported to replace the conventional and fragile indium‐tin oxide (ITO); however, obtaining feasible printed transparent electrodes for ultraflexible devices with a multistack structure is still a great challenge. Here, a printed ultrathin (uniform thickness of 100 nm) Ag mesh transparent electrode is demonstrated, simultaneously achieving high conductance, high transparency, and good mechanical properties. It shows a 17 Ω sq?1 sheet resistance (Rsh) with 93.2% transmittance, which surpasses the performance of sputtered ITO electrodes and other ultrathin Ag mesh transparent electrodes. The conductance is stable after 500 cycles of 100% stretch/release deformation, with an insignificant increase (10.6%) in Rsh by adopting a buckling structure. Furthermore, organic photovoltaics (OPVs) using our Ag mesh transparent electrodes achieve a power conversion efficiency of 8.3%, which is comparable to the performance of ITO‐based OPVs.  相似文献   
47.
Boolean network tomography is a promising technique to achieve fault management in networks where the existing IP-based troubleshooting mechanism cannot be used. Aiming to apply Boolean network tomography to fault management, a variety of heuristic methods for configuring monitoring trails and paths have been proposed to localize link failures in managed networks. However, these existing heuristic methods must be executed in a centralized server that administers the entire managed network and the methods present scalability problems when applied to large-scale managed networks. Thus, this paper proposes a novel scheme for achieving lightweight Boolean network tomography in a decentralized manner. The proposed scheme partitions the managed network into multiple management areas and localizes link failures independently within each area. This paper also proposes a heuristic network partition method with the aim of efficiently implementing the proposed scheme. The effectiveness of the proposed scheme is verified using typical fault management scenarios where all single-link failures and all dual-link failures are localized by the least number of monitoring paths on predetermined routes. Simulation results show that the proposed scheme can greatly reduce the computational load on the fault management server when Boolean network tomography is deployed in large-scale managed networks. Furthermore, the degradation of optimality in the proposed scheme can be mitigated in comparison with a centralized scheme that utilizes heuristics to reduce the computational load on the centralized server.  相似文献   
48.
Semiconducting π-conjugated polymers are the most promising candidates for flexible electronics owing to their facile processability and mechanical robustness; however, achieving steep and stable switching operations in polymer thin-film transistors (TFTs) remains a serious challenge. Herein, it is shown that whole optimizations for eliminating interfacial carrier traps throughout the conductive path are necessary in achieving TFTs showing both exceptionally sharp switching and bias-stress-free characteristics. Inverted-coplanar-type TFTs composed of a highly lyophobic amorphous perfluoropolymer gate–dielectric interfaced with a push-coated semiconducting polymer layer are manufactured. The use of the dielectric allows the establishment of bias-stress-free characteristics with minimized contact resistance. Additionally, fairly sharp on/off switching TFTs with the smallest normalized subthreshold swing can be obtained by utilizing a particular donor–acceptor copolymer that involves a self-passivation mechanism working to achieve a trap-minimized interface. These findings have opened a way for low-power and robust device operations in polymer-based flexible electronics.  相似文献   
49.
Hydrated sodium manganese oxide was synthesized by reducing permanganate ion using ethanol by a sol–gel method. By including acetylene black in the synthetic reaction, we obtained composite materials in which sodium manganese oxide hydrate particles were small and mixed well with the acetylene black. We evaluated those composites as a lithium battery cathode and found that they showed 170 mA h g−1 under 5 mA g−1 and 117 mA h g−1 under 5 A g−1 on the basis of composite weight. This rapid discharge performance was probably caused by the favorable contact condition of the composite constituents.  相似文献   
50.
Recent work has suggested that hawk moths share pheromone components but are sexually separated by qualitative and quantitative differences in their pheromone blends. During field assays on the sex pheromones of other species, a diurnal hawk moth, Neogurelca himachala sangaica (Lepidoptera: Sphingidae), was frequently captured, but the composition of the sex pheromone of this species was not known. Analysis of hexane extracts of the pheromone glands of calling female by gas chromatography (GC) using an electroantennographic detector (EAD) revealed two components that elicited EAD responses from male moth antennae. These components were identified by their mass spectra and retention indices on two GC columns as (10E,12Z)-10,12-hexadecadienal (E10,Z12–16:Ald) and a trace of its (10E,12E)-isomer (E10,E12–16:Ald) in 98:2 ratio. In field experiments, E10,Z12–16:Ald alone attracted male moths, and addition of E10,E12–16:Ald significantly reduced the attractiveness, even at the naturally-occurring ratio. Analysis of the data using a generalized linear mixed model showed that E10,Z12–16:Ald positively contributed to attractiveness, whereas E10,E12–16:Ald did so negatively, and it was concluded that the sex pheromone of N. himachala sangaica consists solely of E10,Z12–16:Ald, bombykal. The negative effect of E10,E12–16:Ald on attractiveness could promote the species-specificity of this single-component pheromone system.  相似文献   
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