Silica glass was implanted with negative 60 keV Cu ions at an ion flux from 5 to 75 μA/cm2 up to a fluence of 1 × 1017 ions/cm2 at initial sample temperatures of 300, 573 and 773 K. Spectra of ion-induced photon emission (IIPE) were collected in situ in the range from 250 to 850 nm. Optical absorption spectra of implanted specimens were ex situ measured in the range from 190 to 2500 nm.
IIPE spectra showed a broad band centered around 560 nm (2.2 eV) that was assigned to Cu+ solutes. The band appeared at the onset of irradiation, increased in intensity up to a fluence of about 5 × 1015 ions/cm2 and then gradually decreased indicating three stage of the ion beam synthesis of nanoclusters: accumulation of implants, nucleation and growth nanoclusters. The IIPE intensity normalized on the ion flux is independent on the ion flux below 20 μA/cm2at higher fluences. The intensity of the band increased with increasing samples temperature, when optical absorption spectra reveal the increase of Cu nanoparticles size. 相似文献
Temperature dependence of the Raman spectrum of lithium oxide single crystal has been measured over a temperature range of 80 to 1073 K. The frequency shift and the line width of the Raman spectrum in lithium oxide were about 531 and 4.5 cm-1 at 80 K, respectively. At 1073 K, the frequency shift and the line width attained the values of 464 and 112 cm-1, respectively. The strong temperature dependence of the frequency shift and line width was compared with data from some crystals with a fluorite structure. 相似文献
A laboratory-scale prototype windowed internally circulating fluidized-bed reactor made of quartz sand and coal coke particles was investigated for steam gasification using concentrated Xe-light radiation as the energy source. The quartz sand was used as a chemically inert bed material for the fluidized bed, while the coal coke particles functioned as the reacting particles for the endothermic gasification reaction. The advantages of using quartz sand as the bed material for the directly irradiated gasification reactor are as follows: (1) The bed height is maintained at a constant level during the gasification. (2) The quartz sand functions as a thermal transfer/storage medium inside the reactor. The gasification performances such as the production rates of CO, H2, and CO2; carbon conversion; and light-to-chemical energy conversion were evaluated for the fluidized-bed reactor with a thermal transfer/storage medium (quartz sand). The effects of using the bed material (quartz sand) on the gasification performance are described in this paper. 相似文献
In this paper, return link systems for wireless mobile camera using 42 GHz-band in multipath fading environments are proposed. The return link systems for wireless mobile camera require wireless transmission with high reliability as same as the conventional wired camera systems. The proposed return link systems achieve transmission with high reliability by taking into consideration frequency and space diversity techniques. The proposed systems can be classified as 3 three types of return link systems according to diversity techniques: FD (frequency diversity) systems, SD (space diversity) systems and FD+SD system (frequency and space diversity). Computer simulations are carried out in order to confirm the effectiveness of the proposed return link systems. It is confirmed that the proposed three types of return link systems have an advantage about BER performances and effectively exploit frequency and space resources. 相似文献
Thermoelectric materials have received much attention recently from the viewpoint of global environmental issues and effective
utilization of energy resources. Especially those effective at relatively low temperature, such as below 100°C, which are
usually abandoned without use, have become noteworthy recently. From this point of view, organic thermoelectric materials
are most attractive, because they could be prepared at low cost and applied in various locations due to their flexibility.
We have investigated the thermoelectric properties of organic conducting polymers such as polyaniline, polypyrrole, and polyphenylenevinylene,
and succeeded in increasing the thermoelectric performance by selecting dopants, stretching conducting films, etc. Recently
we have focused on new systems of organic–inorganic hybrid thermoelectric materials. Herein we present the preparation of
a novel system of hybrids of polyaniline and bismuth(III) telluride nanoparticles, starting from bismuth(III) chloride and
tetrachlorotellurium by using polyvinylpyrrolidone as a protecting reagent, as well as their thermoelectric properties. The
hybrids prepared by this particular method showed much higher thermoelectric performance than the starting organic conducting
polymer. 相似文献
The current work expresses considerations about some of the differences of the fused flux CIS-F10 obtained by means of fragmentation in water and with an air jet. The comparisons are established taking into account their respective granulometric distributions, shapes and grain densities, as well as the energy and the time spent in the process of obtaining each of these variants. Criteria for the physical process of flux fragmentation with an air jet and its influence over the aspects formerly mentioned are also included. The principal findings were that the process for obtaining the fused flux CIS-F10 granulated with an air jet consumes 37% less energy and 25% less time than the one performed with pouring water. The solidness grade of the spherical grains, granulated with air, (with pycnometric density 2.31 g/cm3), with a granulometric distribution more continuous than that of the granules in water, contributes to the increase of the apparent density (11%) of the flux and promotes the creation of artificial granulometric distributions, counteracting the rolling effect during welding. 相似文献
Cell transformation in vitro is a model of carcinogenesis in vivo. Two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. [60]Fullerene (C60) was cytotoxic in BALB/3T3 cells when it was irradiated by visible light, but not without light irradiation. Under conditions when C60 was cytotoxic, it acted as an initiating agent for cell transformation, but it did not act as a complete transforming agent. the initiating activity of visible-light-irradiated C60 was statistically significant in a modified two-stage transformation assay including a procedure for replating cells treated by C60 and light, but it was equivocal in the standard two-stage transformation assay. 相似文献
We have found that the short-circuit current, Jsc, of polymer/fullerene [RR-P3HT/C60] solar cells has a clear dependence on the surface roughness of the ITO/glass substrate. We prepared an ITO surface with an average roughness, Ra, of 0.7–11 nm by chemical etching. At first Jsc increases with the increase in ITO surface roughness and then gradually decreases. The maximum performance was obtained at Ra≈4 nm. Jsc is also high with a very flat surface of Ra=0.7 nm. This feature can be attributed to the trade-off between the increase in absorption light path length and film-quality deterioration. 相似文献
The purpose of this study is to create a natural fiber-reinforced fully green composite with excellent toughness. By treating
ramie plied yarns in a high concentration alkali solution, the reinforcements were mercerized. Results of tensile tests showed
that unidirectional composites using mercerized ramie yarns exhibited two to three times larger fracture strain, without a
marked decrease in strength, than composites using untreated yarns. In addition, mercerization for the ramie yarns brings
a better interfacial strength to the composites. Laminated composites using mercerized ramie yarns also showed approximately
twice larger impact energy than composites using untreated yarns. Thus, mercerization for natural fibers is expected for application
to mechanical materials requiring a high toughness. 相似文献