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排序方式: 共有112条查询结果,搜索用时 15 毫秒
1.
Control of the size of silver sulphide semiconductor particles in functionalized reverse micelles was achieved by changing the water content and intermicellar interactions. Opposite to what it is generally observed in reverse micelles, the size of the crystallites varies linearly with water content from 2 to 10 nm. By changing the intermicellar potential, the size distribution slightly decreases and the stability of the particles with time increases. 相似文献
2.
The reaction which occur during heating, from room temperature to 1100°C, of a mixture of hydroxyapatite, Ca10(PO4)6(OH)2 [HAP] and ammonium sulfate (NH4)2SO4 [AS] are studied. The formation of Ca2(NH4)2(SO4)3, Ca2P2O7 and Ca(PO3)2 is observed between 200°C and 300°C; at 400°C CaSO4 appears. From 500 to 700°C, Ca(PO3)2 reacts with Ca SO4 and with HAP and gives β-Ca2P2O7. Lastly, from 700°C to 1000°C, β-Ca2P2O7 reacts with HAP and with CaSO4 and gives β-Ca3(PO4)2 [β-TCP]; From 1000 to 1100°C, β-TCP and CaSO4 react and form a sulfate ion containing calcium phosphosulfate, the structure of which is β-TCP 相似文献
3.
J-C. Hénaux G. Vernet R. Adde 《Journal of Infrared, Millimeter and Terahertz Waves》1983,4(4):665-680
The system temperature of a receiver using a Josephson junction as a self oscillator mixer has been measured in the range 0.6 to 2 THz. The experimental value TS=53000K (DSB) at 900 GHz is in good agreement with the calculated value. A TS~12 000 K is predicted with a 30 K i.f. amplifier Possible applications are related to fast frequency tunable receivers (over one octave) with limited spectral resolution. 相似文献
4.
Guiomar Martín-Herrán Pierre Cartigny Estelle Motte Mabel Tidball 《Computers & Operations Research》2006
In this paper, our concern is with deforestation as a global environmental issue. Foreign transfers from developed or Northern countries to developing or Southern countries have been proposed to deal with that issue. We use a Stackelberg differential game approach where the two players are: a donor community (the leader) and a recipient country (the follower). We study the impact of different specifications for the transfer function, related to the different information structures the players can consider when playing the Stackelberg game. The different scenarios are compared both from the environmental and economic points of view. 相似文献
5.
Improvement of corrosion protection offered to galvanized steel by incorporation of lanthanide modified nanoclays in silane layer 总被引:1,自引:0,他引:1
C. Motte M. Poelman A. Roobroeck M. Fedel F. Deflorian M.-G. Olivier 《Progress in Organic Coatings》2012
Silane sol–gel based films are very promising alternatives to the traditional chromate pre-treatments. However, the protection offered by the silane films strongly decreases when the coating is damaged. Some previous studies showed that the barrier properties of the silane layer can be improved by incorporation of clay nanoparticles. Moreover, inhibitive metallic cations can be incorporated in the nanoclays by ion exchange, providing a way to prepare cheap corrosion inhibitors nanoreservoirs offering self-healing properties. Rare earth (RE) metal salts have been shown to be effective corrosion inhibitors on a wide range of metals, including hot dip galvanized (HDG) steel. For this study, montmorillonite clay is modified to obtain a Ce(III) montmorillonite clay (Ce-MMT). The amount of incorporated Ce(III) is characterized by means of XRF measurements. X-ray diffraction showed that the Ce(III) is located in the interlayer space. 相似文献
6.
Charlier JC 《Accounts of chemical research》2002,35(12):1063-1069
Carbon nanotubes are quasi one-dimensional nanostructures with unique eletrical prroperties that make them prime candidates for molecular electronics, which is certainly a most promising direction in nanotechnology. Early theoretical works predicted that the electronic properties of "ideal" carbon nanotubes depend on their diameter and chirality. However, carbon nanotubes are probably not as perfect as they were once thought to be. Defects such as pentagons, heptagons, vacancies, or dopant are found to modify drastically the electronic properties of these nanosystems. Irradiation processes can lead to interesting, highly defective nanostructures and also to the coalescence of nanotubes within a rope. The introduction of defects in the carbon network is thus an interesting way to tailor its intrinsic properties, to create new potential nanodevices. The aim of the present Acount is to investigate theoretically the effects of different types of defects on the electronic properties of carbon nanotubes, and to propose new potential applications in nanoelectronics. 相似文献
7.
通过调整培养基中氮源的含量,利用白腐菌Phanerochaete chryscoporium和Trametes versicolor对杨木木片处理28 d,分析了木片的质量得率及化学成分的变化.结果表明:当酵母浸出粉的用量为1 g.L-1时白腐菌对原料中的木素降解率最高,在氮源用量相同的情况下,白腐菌Phanerochaete chryscoporium比Tranetes versicolor降解木素的速率更快. 相似文献
8.
9.
F. J-C. Bouchart H. M. Salleh J. W. Sawkins P. W. Jowitt 《Water and Environment Journal》2001,15(1):21-26
During the last few years, the introduction of mandatory leakage targets for UK water companies has had the positive effect of reducing levels of leakage, while requiring the companies to operate at an economic level of leakage. Unfortunately, the determination of company-specific economic levels of leakage have been a source of disagreement between the water companies and the Government, with the Government view that water companies are not using the true long-term marginal costs of water abstraction, and therefore are not safeguarding the environment.
This paper (a) reviews the model which was used to define the economic level of leakage, (b) argues the case for resource management based on the impact of water abstractions on the socio-environmental quality of a resource rather than the myopic focus on leakage reductions, (c) presents the concepts of effectiveness and efficiency in relation to socio-environmental quality, and (d) proposes a new methodology which allows the determination of water abstraction rates while maintaining a desired level of socio-environmental quality. 相似文献
This paper (a) reviews the model which was used to define the economic level of leakage, (b) argues the case for resource management based on the impact of water abstractions on the socio-environmental quality of a resource rather than the myopic focus on leakage reductions, (c) presents the concepts of effectiveness and efficiency in relation to socio-environmental quality, and (d) proposes a new methodology which allows the determination of water abstraction rates while maintaining a desired level of socio-environmental quality. 相似文献
10.
Louis-B. Jugnia D. Debroas J-C. Romagoux J. Dévaux 《Lakes & Reservoirs: Research and Management》2004,9(2):109-117
We examined the impacts of remediation activities aimed at improving the water quality of hypereutrophic Villerest Reservoir, in which Microcystis aeruginosa dominated during the summer. We also compared nutrients and chlorophyll a data from this study with the results of a previous study on the reservoir. Between the two studies, the nitrogen and phosphorus loads into the reservoir from the main tributary decreased by 70% and 80%, respectively. Within the reservoir, the quantities of ammonia‐nitrogen were similar in the two studies, and the total nitrogen was significantly higher in this study compared to the initial study. Both the phosphate‐phosphorus and total phosphorus concentrations decreased significantly between the two studies. However, the statistically significant decrease in phosphate‐phosphorus and total phosphorus did not always lead to a significant decrease in chlorophyll a concentrations. The nitrogen/phosphorus mass ratio during the present study remained well above five, the critical value below which summer blooms of Microcystis aeruginosa were observed in Villerest Reservoir. These study results indicated that the remediation activities being used to improve the water quality of Villerest Reservoir were off to a good start. 相似文献