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951.
Seyed Nezameddin Ashrafizadeh Zahra Seifollahi Ardalan Ganjizade Arman Sadeghi 《Electrophoresis》2020,41(1-2):81-103
Theories on the electrophoresis of spherical soft particles suspended in an electrolyte solution are thoroughly reviewed. The review predominantly covers studies on the electrophoresis in dilute and concentrated suspensions as well as bounded media, carried out mainly during the past two decades. Moreover, studies on the electrostatics of soft particles are also surveyed. Finally, the research gaps and prospects of the electrophoresis of soft particles are presented. 相似文献
952.
953.
Tatsuya Fukushima Hirotaka Ishibashi Daichi Suemasa Ryosuke Nakamura Masanobu Yomogida Takuya Isono Toshifumi Satoh Hironori Kaji 《Journal of Polymer Science.Polymer Physics》2019,57(5):266-271
In this study, cyclic poly(3‐hexylthiophene‐2,5‐diyl) (c‐P3HT) with a controlled Mn was synthesized by the intramolecular cyclization of α‐bromo‐ω‐ethynyl‐functionalized P3HT via the Sonogashira coupling reaction. The effect of the cyclic structure, which does not have terminal groups of polymers, on the photoelectric conversion characteristics was investigated in comparison to linear P3HT (l‐P3HT). c‐P3HT was successfully synthesized with Mn ≈ 17,000, dispersity ≈ 1.2, and regioregularity ≈ 99%. The hole mobility was determined to be 5.1 × 10?4 cm2 V?1 s?1 by time‐of‐flight (TOF) experiment. This was comparable to that of l‐P3HT of 5.6 × 10?4 cm2 V?1 s?1. Organic solar cell systems were fabricated with each polymer by blending them with [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM). The l‐P3HT:PC71BM system showed a dispersive TOF photocurrent profile for electron transport, whereas a nondispersive profile was observed for c‐P3HT:PC71BM. In addition, an amount of collected electrons in c‐P3HT:PC71BM was greater than that in l‐P3HT:PC71BM for TOF experiments. The photoelectric conversion characteristics were improved by using c‐P3HT rather than l‐P3HT (power conversion efficiency [PCE] = 4.05% vs 3.23%), reflecting the nondispersive transport and the improvement of electron collection. PCEs will be much improved by applying this cyclic concept to highly‐efficient OSC polymers. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 266–271 相似文献
954.
《Physics letters. A》2020,384(22):126431
Based on the first-principles calculations, we confirm the geometry and electronic structures of two binary group-VI compounds: monolayer α-Se2Te and α-SeTe2. The stabilities are confirmed by the cohesive energies, phonon dispersions, and elastic constants. The mechanical properties, strain-stress relationships, and strain-dependent variations of band gaps and band structures are investigated detailed. Furthermore, the high carrier mobilities (up to cm2 V−1 s−1) and optical absorption coefficients (several 105 cm−1) are also exhibited, demonstrating the great application potentials in optoelectronics. 相似文献
955.
956.
Structural and electrical properties of laser-crystallized nanocrystalline Ge films and nanocrystalline Ge/SiN_x multilayers 下载免费PDF全文
Nanocrystalline Ge (nc-Ge) single layers and nc-Ge/SiNx multilayers are prepared by laser annealing amorphous Ge (a-Ge) films and a-Ge/SiNx multilayers. The microstructures as well as the electrical properties of laser-crystallized samples are systematically studied by using various techniques. It is found that the optical band gap of nc-Ge film is reduced compared with its amorphous counterpart. The formed nc-Ge film is of p-type, and the dark conductivity is enhanced by 6 orders for an nc-Ge single layer and 4 orders for a multilayer. It is suggested that the carrier transport mechanism is dominant by the thermally activation process via the nanocrystal, which is different from the thermally annealed nc-Ge sample at an intermediate temperature. The carrier mobility of nc-Ge film can reach as high as about 39.4 cm2.V ^-1 .s^-1, which indicates their potential applications in future nano-devices. 相似文献
957.
Celine I.L. Justino Teresa A. Rocha-Santos Armando C. Duarte 《Trends in analytical chemistry : TRAC》2011,30(3):554-567
Efficient sampling and characterization of nanoparticles have been challenging tasks in environmental research due to the limitations of regular analytical techniques (e.g., dynamic light scattering, and nuclear magnetic resonance and UV-Vis spectroscopies) - especially the difficulties in their application to in situ and real-time monitoring, which are intrinsically related to the nanometer-size range.This critical overview aims at characterizing recent instrumental techniques (e.g., hygroscopic tandem-differential mobility analysis, thermal desorption-gas chromatography-mass spectrometry, and time-of-flight secondary ion mass spectrometry) for sampling and characterization of individual nanoaerosols in terms of their general operation principles, analytical parameters, advantages and limitations. We also discuss classification of this instrumentation based on off-line and/or in situ methods, and on physical and chemical characterization of nanoaerosols. Further, we summarize recent air-quality studies aimed at understanding the physical and chemical behavior of aerosols in different environments. 相似文献
958.
A quinoidal small‐molecule semiconductor QDPPBTT was synthesized. Organic thin‐film transistor (OTFT) devices based on QDPPBTT showed an electron mobility as high as 0.13 cm2 V?1 s?1 and Ion/Ioff ratio of 106 under ambient conditions. We suggested that 2D extended π‐conjugation and quinoid‐enhancing effect had an important role in electron mobility and stability of n‐type FET devices, which might be a good strategy in designing new material systems. 相似文献
959.
Alexander E. Khudozhitkov Dr. Sergey S. Arzumanov Dr. Daniil I. Kolokolov Prof. Oxana A. Kholdeeva Prof. Dieter Freude Prof. Alexander G. Stepanov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(20):5163-5168
We present investigation of the effect of electron-donor guests on framework mobility in the metal–organic framework (MOF) MIL-101(Cr) monitored by solid state 2H NMR spectroscopy. In a guest-free material, the mobile phenylene fragments of the terephthalate (TP) linkers populate two fractions with notably different kinetic parameters for torsional motion. Two fractions of rotational motion are indicative of non-equivalence of TP linker binding to the Cr3O trimer, the primary building unit of the MIL-101 framework. It is established that the interaction of the guest molecules with coordinatively unsaturated metal sites (CUS) of the MOF dramatically decreases torsional barriers for the linker motions, enhancing the rotation rate. This result is opposite to a more conventional slowing down effect on the linker rotation of the guests not selectively interacting with the adsorption sites inside the framework of the MOFs. The effect of coordination on both the torsional barrier and the rotation rate depends notably on the particular guest interacting with the CUS. The found effects of the guest on the rotational motion represent a basis for developing the strategy for ruling and controlling the linker rotation in MOFs with CUS. It is shown that if water occupies CUS, another guest (tert-butanol, cyclohexanone) fails to competitively coordinate to the site. 相似文献
960.
Complex models are usually needed to predict functional performance of mechanical devices such as noise and vibration levels. A typical model is divided into substructures where each substructure is described either as a simulation or as an experimental model. When coupling substructures, information is needed that describes the boundary conditions at the attachment points of the various substructures. This can be hard to achieve, especially when full structural behavior including rotational degrees of freedom (DOFs) are needed. The objective of this study was to obtain the mechanical mobility matrix in six DOFs for a wheel hub of car, as an example of a complex mechanical structure, through an experimental approach based on the multiple-input multiple-output technique. Further, evaluation of the measurement quality was conducted without requirements for numerical simulation comparisons. A specially designed brake disc was fabricated for direct attachment of shakers and transducers. The quality of the 6-DOF mechanical mobility matrix was evaluated using reciprocities, coherence functions, and random error in the gain-factor estimates. The results showed good quality in the reciprocities, and the multiple coherences in each degree of freedom were close to one in the frequency range of 25–500 Hz. The random error can be reduced by increasing the number of averages. 相似文献