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181.
We present a vision chip architecture with column-level photo-amplification of optical data signals for optical wireless local
area networks (LANs) to reduce the pixel area. Based on the architecture, we have fabricated a prototype vision chip in a
standard 0.8 μm bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. The device offers position detection
of other optical transceivers in the LAN and 4-ch concurrent high-speed optical data acquisition. A data rate of 400 Mbps
was demonstrated. The pixel size was 125 μm square, which can be shrunk to smaller than around 60 μm square in 0.35 μm or
more advanced BiCMOS or CMOS technologies. 相似文献
182.
Alternate hetero-arm copolymer brushes were synthesized by free-radical copolymerizations of vinylbenzyl-terminated polystyrene macromonomers (PS-VB) with a methacryloyl-terminated poly(ethylene oxide) macromonomer (PEO-MA)/tin tetrachloride (SnCl(4): Lewis acid) complex. Dilute solution properties of such hetero-arm copolymer brushes were investigated by static and dynamic light scattering. Effective diffusion coefficients D(eff) for copolymer brushes possessing large aspect ratios showed almost constant values in the range of polymer concentrations 0-6x10(-3) g/cm(3). These results mean that copolymer brushes formed unimolecular structures even in a good solvent such as benzene. It was speculated from angular dependence measurements that in solution copolymer brushes take geometrically anisotropic conformations such as cylinders. To determine the phase-separated cylindrical domains of alternate copolymer brushes, we constructed large aggregates of copolymer brushes in water. Consequently, alternate copolymer brushes seemed to lead self-assemblies among phase-separated hydrophobic PS domains. Copyright 2001 Academic Press. 相似文献
183.
Numata M Yarita T Aoyagi Y Tsuda Y Yamazaki M Takatsu A Ishikawa K Chiba K Okamaoto K 《Analytical and bioanalytical chemistry》2007,387(7):2313-2323
Two marine sediment certified reference materials, NMIJ CRM 7304-a and 7305-a, have been issued by the National Metrology
Institute of Japan in the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) for the determination
of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The raw materials of the CRMs were collected from
a bay near industrial activity in Japan. Characterization of these CRMs was conducted by NMIJ, where the sediments were analyzed
using multiple analytical methods such as pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), saponification,
Soxhlet extraction, supercritical fluid extraction (SFE), and ultrasonic extraction; the target compounds were determined
by one of the primary methods of measurements, isotope dilution–mass spectrometry (ID-MS). Certified values have been provided
for 14 PCB congeners (PCB numbers 3, 15, 28, 31, 70, 101, 105, 138, 153, 170, 180, 194, 206, 209) and 4 OCPs (γ-HCH, 4,4′-DDT,
4,4′-DDE, 4,4′-DDD) in both CRMs. NMIJ CRM 7304-a has concentrations of the contaminants that are a factor of 2–15 greater
than in CRM 7305-a. Both CRMs have information values for PCB homolog concentrations determined by collaborative analysis
using a Japanese official method for determination of PCBs. The total PCB concentrations in the CRMs are approximately 920
and 86 μg kg−1 dry mass respectively.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
184.
Maeda H Yamamoto K Kohno I Hafsi L Itoh N Nakagawa S Kanagawa N Suzuki K Uno T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(7):1946-1954
A strategy for designing probes based on protection-deprotection chemistry involving fluoresceins and their benzenesulfonyl (BES) derivatives has led to the development of a much more practical superoxide (O(2) (-.)) probe than the previously reported bis(2,4-dinitro-BES) tetrafluorofluorescein (6 a). Examination of various BES derivatives, developed from the starting point of the prototype probe 6 a, yielded 4,5-dimethoxy-2-nitro-BES tetrafluorofluorescein (BESSo; 7 j) as the optimal reagent. A microtiter plate assay with BESSo showed a tenfold improved detection limit for O(2) (-.) compared with such an assay based on 6 a. BESSo showed markedly better specificity for O(2) (-.) than for GSH or other reactive oxygen species, and this specificity was significantly higher than that of Fe(2+) and some reducing enzymes. These features have resulted in the development of an assay based on BESSo that is capable of providing more unambiguous results for O(2) (-.) release from neutrophils, with or without stimulation by phorbol myristate acetate, as compared with an assay based on 6 a. Intracellular generation of O(2) (-.) in human Jurkat T cells stimulated by butyric acid has been measured by using flow cytometry and fluorescence microscopy utilizing the acetoxymethyl derivative of BESSo. 相似文献
185.
Yamamura M Kano N Kawashima T Matsumoto T Harada J Ogawa K 《The Journal of organic chemistry》2008,73(21):8244-8249
2,2'-Bis(fluorodiphenylsilyl)azobenzenes bearing two methyl and butyl groups at the 4- and 4'-positions were synthesized, and their X-ray crystallographic analyses revealed that they have tetracoordinated and pentacoordinated silicon atoms, respectively. Although the two compounds showed almost the same spectra in solution, the reflectance spectra of the solid revealed that the pentacoordinated state had a weaker absorbance in the long-wavelength region compared with that of the tetracoordinated state, which is ascribed to the shift of the n-pi* transition. This difference in the absorptions due to the n-pi* transition drastically affects the color of the azobenzenes: the color of the pentacoordinated state becomes apparently paler than that of the tetracoordinated state. 相似文献
186.
Basic micropattern shapes, such as stripes and teardrops, affect individual facets of cell motility, such as migration speed and directional bias, respectively. Here, we test the idea that these individual effects on cell motility can be brought together to achieve multidimensional improvements in cell behavior through the modular reconstruction of the simpler "building block" micropatterns. While a modular design strategy is conceptually appealing, current evidence suggests that combining environmental cues, especially molecular cues, such as growth factors and matrix proteins, elicits a highly nonlinear, synergistic cell response. Here, we show that, unlike molecular cues, combining stripe and teardrop geometric cues into a hybrid, spear-shaped micropattern yields combinatorial benefits in cell speed, persistence, and directional bias. Furthermore, cell migration speed and persistence are enhanced in a predictable, additive manner on the modular spear-shaped design. Meanwhile, the spear micropattern also improved the directional bias of cell movement compared to the standard teardrop geometry, revealing that combining geometric features can also lead to unexpected synergistic effects in certain aspects of cell motility. Our findings demonstrate that the modular design of hybrid micropatterns from simpler building block shapes achieves combinatorial improvements in cell motility. These findings have implications for engineering biomaterials that effectively mix and match micropatterns to modulate and direct cell motility in applications, such as tissue engineering and lab-on-a-chip devices. 相似文献
187.
Crystal structures of 1,2-diphenylethane (1), 1,2-bis(4-dimethoxyphenyl)ethane (3), 1,2-bis(2,3-dimethylphenyl)ethane (4), 1,2-bis(2,4-dimethylphenyl)ethane (5) and 1,2-bis(2,4,6-trimethylphenyl)ethane (6) were determined by X-ray diffraction analysis at various temperatures. An apparent shortening of the ethane bond and its temperature dependence were observed and it was interpreted as an artifact caused by the torsional vibration of the C—Ph bonds in crystals. The extent of the shortening was dependent on the compounds and was explained in terms of the difference in the amplitude of the torsional vibration controlled by ortho methyl groups. In the crystal structures of 1, a so far unrecognized orientational disorder was observed at room temperature and 315 K. The disorder, which disappeared at lower temperatures, proved to be dynamic and was ascribed to a conformational interconversion through a very large amplitude torsional vibration. The disorder might be another reason for the exceptionally short ethane bond in 1. 相似文献
188.
Takuya Kuwahara Keiichiro Yoshida Tomoyuki Kuroki Kenichi Hanamoto Kazutoshi Sato Masaaki Okubo 《Plasma Chemistry and Plasma Processing》2014,34(1):65-81
Regulations governing marine diesel engine NOx emissions have recently become more stringent. As it is difficult to fulfill these requirements by combustion improvements alone, effective aftertreatment technologies are needed to achieve efficient NOx reductions. In this study, we develop an effective NOx-reduction aftertreatment system for a marine diesel engine that employs combined nonthermal plasma (NTP) and adsorption. Compared with selective catalytic reduction, the proposed technology offers the advantages of not requiring a urea solution or harmful heavy-metal catalysts and low operating temperatures of less than 150 °C. The NOx reduction comprises repeated adsorption and desorption flow processes using NTP combined with NOx adsorbents made of MnOx–CuO. High concentrations of NOx are treated by NTP after NOx adsorption and desorption, and this aftertreatment system demonstrates excellent energy efficiencies of 161 g(NO2)/kWh, which fulfills the most recent International Maritime Organization emission NOx standards in the Tier II–III regulations for 2016 and requires only 4.3 % of the engine output power. 相似文献
189.
Piezoelectric elastomers were prepared from suspensions of bariumtitanate (BaTiO3) particles in a telechelic polydimethylsiloxane (t-PDMS) by crosslinking the t-PDMS under an electric field. Crosslinking reaction was monitored by measurement of complex dielectric constant ε′ − iε″. Dielectric constant ε′ increased with increasing BaTiO3 content, and agreed approximately with the theoretical ε′ calculated with the Maxwell–Wagner theory. Piezoelectric constant d33 of the poled elastomers was measured by application of compressions in the direction of the poling field. It was found that d33 was of the order of 10−11 C/N and increased steeply with increasing content of BaTiO3 but became almost independent of composition in the range of BaTiO3 content from 3 to 14 vol %. To examine the effect of electric field on the aggregation structure of the particles, we observed light scattering of the suspension under an electric field, and found that the scattering pattern became anisotropic. This indicated that the particles are connected like a pearl necklace and are stretched in the direction of the poling field. The dependence of d33 on the volume fraction of BaTiO3 was explained by a model proposed by Banno. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 3065–3070, 1999 相似文献
190.
Juan J. Freire Luis A. Molina Antonio Rey Keiichiro Adachi 《Macromolecular theory and simulations》1999,8(4):321-327
A dynamic Monte Carlo algorithm is employed to investigate the dynamics of flexible linear and star chains on a cubic lattice at different concentrations. Some results for similar systems are also obtained with an off‐lattice algorithm. Diffusion coefficient, relaxation times and mean size data are combined into friction‐independent ratios in good agreement with the theoretical predictions from the Rouse theory. The relaxation times and amplitudes corresponding to the Rouse normal modes are analyzed in terms of their variation with the mode order. The end‐to‐end vector correlation times obtained from the simulations for linear chains are compared with the theoretical expression obtained from the Rouse theory. Deviations from this theory are observed for the contribution of the different modes in the non‐dilute systems. Finally, the time correlation function corresponding to a subchain's end‐to‐end vector is investigated. The results also show deviations from the Rouse theory, which are in qualitative agreement with the features observed in data from dielectric relaxation experiments of block copolymers. 相似文献