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951.
Tiwari S.P. Namdas E.B. Ramgopal Rao V. Fichou D. Mhaisalkar S.G. 《Electron Device Letters, IEEE》2007,28(10):880-883
Solution-processed n-type organic field-effect transistors (OFETs) based on the fullerene derivative {6}-1-(3-(2- thienylethoxycarbonyl)-propyl)-{5}-l-phenyl-[5,6]-C61 (TEPP) and phenyl-C61-butyric acid methyl ester (PCBM) in a multiring source/drain structure are reported. Devices with TEPP show high electron mobility up to 7.8 x 10-2 cm2/Vs in the saturation regime for bottom-contact OFETs with Au S/D electrodes with a solution-processed fullerene derivative. The ON/OFF ratios reported in this letter, which are in the range of 105 -106, are among the highest values reported for such devices. This mobility is always higher compared to PCBM devices prepared in identical conditions. The mobility of TEPP and PCBM increased with increasing temperatures in the range of 100-300 K with activation energy of 78 and 113 meV, respectively, which suggests that the thermally activated hopping of electrons is dominant in TEPP. 相似文献
952.
S. Abiraman H. K. Varma T. V. Kumari P. R. Umashankar Annie John 《Bulletin of Materials Science》2002,25(5):419-429
This study investigates quantitatively and qualitatively the sol-gel derived bioactive glass-ceramic system (BGS)—apatite-wollastonite
(AW) type granules in the size range of 0.5–1 mm, as an effective graft material for bone augmentation and restoration. Scanning
electron micrographs (SEM) of the sintered granules revealed the rough material surface with micropores in the range 10–30
μm. X-ray diffraction (XRD) pattern of the granules revealed the presence of crystalline phases of the hydroxyapatite and
wollastonite, and the functional groups of the silicate and phosphates were identified by Fourier transform infrared spectroscopy
(FT-IR). Thein vitro cell culture studies with L929 mouse fibroblast cell line showed very few cells adhered on the BGS disc after 24 h. This
could be due to the highly reactive surface of the disc concomitant with the crystallization but not due to the cytotoxicity
of the material, since the cellular viability (MTT assay) with the material was 80‰ Cytotoxicity and cytocompatibility studies
proved that the material was non-toxic and biocompatible. After 12 weeks of implantation of the BGS granules in the tibia
bone of New Zealand white rabbits, the granules were found to be well osteointegrated, as observed in the radiographs. Angiogram
with barium sulphate and Indian ink after 12 weeks showed the presence of microcapillaries in the vicinity of the implant
site implicating high vascularity. Gross observation of the implant site did not show any inflammation or necrosis. SEM of
the implanted site after 24 weeks revealed good osteointegration of the material with the newly formed bone and host bone.
New bone was also observed within the material, which was degrading. Histological evaluation of the bone healing with the
BGS granules in the tibial defect at all time intervals was without inflammation or fibrous tissue encapsulation. After 2
weeks the new bone was observed as a trabeculae network around the granules, and by 6 weeks the defect was completely closed
with immature woven bone. By 12 weeks mature woven bone was observed, and new immature woven bone was seen within the cracks
of the granules. After 24 weeks the defect was completely healed with lamellar bone and the size of the granules decreased.
Histomorphometrically the area percentage of new bone formed was 67.77% after 12 weeks and 63.37% after 24 weeks. Less bone
formation after 24 weeks was due to an increased implant surface area contributed by the material degradation and active bone
remodeling. The osteostimulative and osteoconductive potential of the BGS granules was established by tetracycline labelling
of the mineralizing areas by 2 and 6 weeks. This sol-gel derived BGS granules proved to be bioactive and resorbable which
in turn encouraged active bone formation. 相似文献
953.
P. Meenakshi S. E. Noorjahan R. Rajini U. Venkateswarlu C. Rose T. P. Sastry 《Bulletin of Materials Science》2002,25(1):25-29
DriedMusa paradiciaca (banana) stem and veins of the leaves, which were hitherto discarded as a waste, were collected and used as starting material
for the preparation of cellulose and cellulose acetate. This cellulose acetate was mixed with polystyrene to form blend of
cellulose acetate-polystyrene in order to provide enhanced stability and extended utility to the end products. The films of
these composites or their individual partners were made separately and studied for their mechanical properties, chemical modification
and morphological changes. We report here that banana stem is good source of cellulose and that cellulose completely undergoes
modification upon esterification. 相似文献
954.
A new sensitive method for imaging of the spatial distribution of microwave intensity is proposed. The method is based on the imaging of the 6P-recombination continuum of cesium, emitted from a nonequilibrium plasma of the positive column of gas discharge in a cesium vapor-xenon mixture. It is demonstrated that the spatial distribution of intensity of 35-GHz microwave radiation measured by this method in a focal plane of a lens well coincides with the pattern obtained with the aid of a movable microwave detector. The time resolution of the proposed microwave imaging system reaches 1 ms. 相似文献
955.
SiC-based field-effect gas sensors with catalytic platinum electrodes (Pt-MOSiC) have been subjected to a series of gas response measurements. Structural analysis of the Pt electrodes revealed that the gas sensitivity and the selectivity of Pt-MOSiC gas sensors depend on two major parameters: the porosity and the catalytic activity of the Pt electrodes. Pt-MOSiC gas sensors with thick, dense Pt electrodes only exhibit hydrogen sensitivity, whereas Pt-MOSiCs with thin porous gates exhibit a broad range of gas sensitivities similar to resistive metal-oxide gas sensors. A model is put forward that explains the nonhydrogen gas response of Pt-MOSiC devices and of conventional polycrystalline metal-oxide materials on a common basis. 相似文献
956.
957.
958.
Recent developments on fiber-optic devices are reviewed from the local area network (LAN) application viewpoint. Future technical trends are also discussed, along with current research activities. In local area network systems, low device cost and easy maintenance or maintenance-free devices are especially required. Light sources and photodetectors suitable for the systems are described. InGaAsP/InP light emitting diodes can cover a broad application field, up to a gigabits per second super high-speed network region. Optical passive devices, which include branching couplers, switches and connectors, are mentioned as essential components. Compact transmitter/receiver module technology is a key factor in realizing optical-fiber local area network systems. An example of 200-Mbit/s transmitter/receiver module is reported. 相似文献
959.
B L Sergeev S P Bogovski? T I Ve?debaum R Kh Tanner I N Shevchuk 《Eksperimental?nai?a onkologii?a》1985,7(5):27-30
The UV irradiation (lambda = 362 nm) of aflatoxin B1 (AfB1) dissolved in water resulted in the formation of an oxidized product. The process was not inhibited by ionol, a routine inhibitor of the radical processes. The oxidized product was not found in the system where AfB1 was metabolized by the 3-methylcholanthrene-activated rat liver microsomes. It is suggested that the product is identical with 2,3-dihydrodiol of AfB1. 相似文献
960.
S. Taye 《Computers & Structures》1991,41(6):1341-1347
An approximate structural reanalysis method that is based on a binomial series expansion and that employs operations of matrix scaling and norm minimization is presented in this paper. It is shown that the scaling operation significantly reduces several unfavourable effects of the magnitude and nature of design changes on the prediction quality of the model. Norm minimization provides a very effective and optimal scaling factor in a simplified manner. The most significant achievement of the work is the development of an effective and efficient reanalysis model that provides near-exact response quantities even when large and strongly dispersed changes are introduced in the design. The potential capacity of the proposed method of improvement is demonstrated using numerical examples. Graphical interpretation of the concept is also provided. 相似文献