23 resultados para 1926


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Gold nanowires with diameters (d) between,15 run and 200 urn and with length/diameter ratio of 700 were prepared in ion-track templates with electrode position method. The morphology and crystal structure of the gold nanowires were Studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The 200 nm (d) gold nanowires preferred orientation along the [100] direction were formed at the deposition voltage of 1.5 V (Without reference electrode). The optical properties of gold nanowire arrays embedded in ion-track templates were studied by UV-Vis spectrophotometer. There was a strong absorption peak at 539 nm for 45 nm (d) gold nanowire arrays. With the diameter of gold nanowires increasing, the absorption peak shifted to the longer wavelength. At last, the result was discussed combined with surface plasmon resonance of gold nanoparticles.

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We report the electrochemical growth of gold nanowires with controlled dimensions and crystallinity. By systematically varying the deposition conditions, both polycrystalline and single-crystalline wires with diameters between 20 and 100 nm are successfully synthesized in etched ion-track membranes. The nanowires are characterized using scanning electron microscopy, high resolution transmission electron microscopy, scanning tunnelling microscopy and x-ray diffraction. The influence of the deposition parameters, especially those of the electrolyte, on the nanowire structure is investigated. Gold sulfite electrolytes lead to polycrystalline structure at the temperatures and voltages employed. In contrast, gold cyanide solution favours the growth of single crystals at temperatures between 50 and 65 degrees C under both direct current and reverse pulse current deposition conditions. The single-crystalline wires possess a [110] preferred orientation.

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The surface of aromatic polyamide reverse osmosis composite membrane was modified by oxygen and argon plasma. The water permeability of oxygen-plasma-modified membrane increases, and the chlorine resistance of argon-plasma-modified membrane increases. The spectra of the attenuated total reflection-Fourier transform infrared and X-ray photoelectron spectroscopy and the contact angle of the water were analyzed to explain the improvement of the two performances of the composite membrane. The carboxyl groups were introduced when modified by oxygen plasma, and cross-linking occurred when modified by argon plasma. (C) 1997 John Wiley & Sons, Inc.

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We studied the morphology of three rare haptorid ciliates, using live observation and silver impregnation: Apertospathula verruculifera n. sp., Longispatha elegans n. gen., n. sp., and Rhinothrix porculus (Penard, 1922) n. gen., n. comb. Simple ethanol fixation (50-70%, v/v) is recommended to reveal the ciliary pattern of "difficult" ciliates, such as R. porculus, by protargol impregnation. The three genera investigated have a distinct feature in common, viz., a lasso-shaped oral bulge and circumoral kinety, where the right half is slightly to distinctly longer than the left and the circumoral kinety is open ventrally. Thus, they are united in a new spathidiid family, the Apertospathulidae n. fam., which probably evolved from a Bryophyllum-like ancestor by partial reduction of the oral bulge and circumoral kinety. Apertospathula verruculifera has a wart-like process, the palpus dorsalis, at the anterior end of the dorsal brush. The right branch of the circumoral kinety is only slightly longer than the left one. Longispatha elegans has a straight oral bulge and circumoral kinety, the right branch of which extends to the posterior end of the body while the left branch ends in the anterior third of the body. Rhinothrix porculus, a curious ciliate with a snout-like dorsal elongation of the oral bulge, the palpus oralis, has a highly characteristic ciliary pattern: the oral pattern is as in Longispatha, but the bulge and circumoral kinety extend spirally to the posterior end of the body while the somatic kinetics course meridionally. This is achieved by inserting some shortened kinetics in the curves of the oral bulge.

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The north steep slope zone of Dongying Depression has great potential in oil resource and as the usage of 3-d seismic data in the last decade, the exploration of oil and gas has get into the stage of sandy glavel body lithological oil-gas pool exploration. In this thesis, writer take the north steep slope zone of Dongying Depression as target area and take Sha-III and Sha-[V Menber as purpose stratum, study on sequence stratigraphy, depositional system, reservoir description, emphasesing on analyzing of forming of lithological oil-gas pool, especially the dynamics principle of oil and gas preliminary movement from the source rock to the reservoir form lithological oil-gas pools. The aim of this work is to give some quantitatively explanation for the mechanism of lithological oil-gas pool forming, and set up the theory of pool form with characteristic terrestrial faulted basin. There are main conclusions and views as follow. 1. Applying with principle of sequence stratigrapgy, according to the depositional cycles of Dongying Depression, the sequence stratigraphical partition of Tertiary was finished, stressing on dismembering Sha-III and Sha-IV Menber as 5system tracts. 2. The structure of Dongying Depression especially of the north steep slope zone has accomplished, including the analyzing the structural cortroling to depositional condition of the north steep slope zone of Dongying Depression, discussed relationship between the structure of the north steep slope zone and the pool-forming. 3. The horizontal and vertical exchanges of ancient climates and ancient physiognomy of the all stratum units and studies on characteristic of depositional system distribution have been finished, found that there are five depositional systems in the north steep slope zone of Dongying Depression as fluvial, delta (tan-delta), sub-water fluvial fan lacustrine, gravitive flow, and seven formations of sandy glavel body, and forecasting of all kinds of sandy glavel body has been made. 4. Seismic stratigraphy and log stratigraphy have been made, described and forecasted all kinds of reservoir of objective stratum by means of physical geography method, setup a series means of sandy glavel body description suit to target area. 5. The pool-forming system has been studied, analyzing all the elements in petroleum sub-system of Sha-III and Sha-IV Menber of Dongying Depression with view of source controlling, estimated the petroleum system applying source rock potential index combining with distribution ofreservior. 6.Through studying types of pool, the controlling factors of pool-forming of sandy glavel body were discussed by deposition stages, formation types, structure ect. as a conclusion that the characteristics of pool forming in the north steep slope zone of Dongying Depression are, the controlling factor of the pools is mainly lithology, petrophysics of oil sands vary greatly, with a large heterogeneity, all kind of reservoir with different formation has different pool-forming conditions, and as a result, formed various pools of sandy glavel body along the steep slope with regular combination, distribution and constituted the multiple petroleum accumulative pattern. 7. It's the first time to cauculate and estimate the fluid pressure in source rock of Dongying Depression, set up the stratum fluid pressure in Dongying Depression, and firstly use equivalent charging pressure and reservoir forming index to quantitatively evaluate the pool-forming condition of lithological pool.8. Above all studies, follow up the scent of the exploration combined with practice a lot of explorative targets were found, and got geat economic and social benefit.