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排序方式: 共有335条查询结果,搜索用时 31 毫秒
11.
Molten salt reactors (MSR) have many non-proliferation attributes. They can operate on the thorium-uranium fuel cycle which protects the fissile material by the daughter products of the inseparable U-232. MSRs can completely fission all plutonium and HEU, and as desired, ‘convert’ them to U-233. This also results in high, and efficient resource utilization, while diminishing the plutonium stock. On line processing, when applied, could free the waste from all fissile material. The fuel in the reactor stays protected by the intense radiation of the fission products. Fuel can also be protected in the reactor as well as outside the reactor by denaturing with natural uranium. A wide variety of MSRs are available, from ‘once through’ minimum processing reactors to ones with fuel processing which can breed fuel for converters. MSRs are extremely safe and simple reactors with good economic potential. 相似文献
12.
Multilayer emulsions containing lipid droplets coated by lactoferrin (LF) - anionic polysaccharide layers have improved resistance to environmental stresses (such as pH, salt, and temperature), but their behavior within the gastrointestinal tract (GIT) is currently unknown. The objective of this research was therefore to monitor changes in the physicochemical properties and digestibility of these systems under simulated GIT conditions. Primary emulsions (5% corn oil, 0.5% LF) were prepared using a high-pressure homogenizer. Secondary emulsions (5% corn oil, 0.5% LF, 0.5% polysaccharide) were prepared by incorporating alginate, low methoxyl pectin (LMP) or high methoxyl pectin (HMP) into primary emulsions. Emulsions were then subjected to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) conditions in sequence. LF, LF-LMP and LF-HMP emulsions were stable to droplet aggregation in the stomach but aggregated in the small intestine, whereas LF-alginate emulsions aggregated in both the stomach and small intestine. The presence of a dietary fiber coating around the initial lipid droplets had little influence on the total extent of lipid digestion in SIF, but LF-alginate emulsions had a slower initial digestion rate than the other emulsions. These results suggest that the dietary fiber coatings may become detached in the small intestine, or that they were permeable to digestive enzymes. Pepsin was found to have little influence on the physical stability or digestibility of the emulsions. The knowledge obtained from this study is important for the design of delivery systems for encapsulation and release of lipophilic bioactive ingredients. 相似文献
13.
An adaptive predictive clock synchronizer for systems on chip incorporating multiple clock domains is presented. The synchronizer
takes advantage of the periodic nature of clocks in order to predict potential conflicts in advance, and to conditionally
employ an input sampling delay to avoid such conflicts. The result is conflict-free synchronization with maximal throughput
and minimal latency. The adaptive predictive synchronizer adjusts automatically to a wide range of clock frequencies, regardless
of whether the transmitter is faster or slower than the receiver. The synchronizer also avoids sampling duplicate data or
missing any input. A novel method is presented for formal treatment of synchronizers and metastability. Correct operation
of the synchronizer is formally proven and verified. 相似文献
14.
Noel D. Uri 《Energy Economics》1980,2(3):179-183
Studies of the determinants of investment behaviour have so far failed to consider the effects of changing energy prices. This paper aims to remedy this omission. After reviewing the theory of investment analysis, the author presents an econometric examination of the role of energy prices in US investment activity. He finds that the price of energy is an important factor in adequately explaining investment decisions and that its importance is likely to grow. 相似文献
15.
Noel D. Uri 《Energy》1980,5(11):1155-1162
The objective of this analysis is to develop a model to forecast the consumption of fossil fuels by electric utilities on a month-to-month basis. A scheme is devised and implemented that attributes fossil-fuel generation (exclusive of coal) to the consumption of residual fuel oil, distillate fuel oil, crude oil, and natural gas. A multinomial logit specification is used whereby the share of each of these fuels is a function of relative prices, weather, time, seasonal factors, and extraneous influences (e.g. a coal strike). The results agree well with actual shares. 相似文献
16.
Dimensionality and size are two factors that govern the properties of semiconductor nanostructures. In nanocrystals, dimensionality is manifested by the control of shape, which presents a key challenge for synthesis. So far, the growth of rod-shaped nanocrystals using a surfactant-controlled growth mode, has been limited to semiconductors with wurtzite crystal structures, such as CdSe (ref. 3). Here, we report on a general method for the growth of soluble nanorods applied to semiconductors with the zinc-blende cubic lattice structure. InAs quantum rods with controlled lengths and diameters were synthesized using the solution-liquid-solid mechanism with gold nanocrystals as catalysts. This provides an unexpected link between two successful strategies for growing high-quality nanomaterials, the vapour-liquid-solid approach for growing nanowires, and the colloidal approach for synthesizing soluble nanocrystals. The rods exhibit both length- and shape-dependent optical properties, manifested in a red-shift of the bandgap with increased length, and in the observation of polarized emission covering the near-infrared spectral range relevant for telecommunications devices. 相似文献
17.
18.
Michal Soreni‐Harari David Mocatta Marina Zimin Yair Gannot Uri Banin Nir Tessler 《Advanced functional materials》2010,20(6):1005-1010
InAs nanocrystals field‐effect transistors with an ON/OFF ratio of 105 are reported. By tailoring the interface regions in the active layer step‐by‐step, the evolution of the ON/OFF ratio can be followed from approximately 5 all the way to around 105. The formation of a semiconducting solid from colloidal nanocrystals is achieved through targeted design of the nanocrystal–nanocrystal interaction. The manipulation characteristics of the nanocrystal interfaces include the matrix surrounding the inorganic core, the interparticle distance, and the order of nanocrystals in the 3D array. Through careful analysis of device characteristics following each treatment, the effect of each on the physical properties of the films are able to be verified. The enhanced performance is related to interparticle spacing, reduction in sub‐gap states, and better electronic order (lower σ parameter). Films with enhanced charge transport qualities retain their quantum‐confined characteristics throughout the procedure, thus making them useful for optoelectronic applications. 相似文献
19.
In 2004, National Aeronautics and Space Administration (NASA) implemented Full Cost, an activity-based accounting program through an agency-wide enterprise resource planning (ERP) implementation. We apply Foucault’s notion of ‘dressage’ to highlight aspects of demonstrative control associated with this implementation effort and to outline the different dimensions along which control was distributed. We suggest that some elements of Full Cost and the ERP system were geared toward satisfying disciplinary requirements without necessarily contributing to productive activity. We term these elements dressage-as-control. Our findings indicate that dressage-as-control breeds dressage-as-response: employees’ responses to control imperatives that are intended merely to satisfy the demand for control by exhibiting public compliance, but make no direct contribution to the execution of work. Accordingly, we propose that the ideal of complete enterprise control remains unattainable, as aspects of demonstrative control are inevitably implicated within broader enterprise-wide control systems within contemporary organizations. We conclude with implications for research and practice. 相似文献
20.