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991.
We investigated the use of an analog self-electrooptic effect device based on GaAs multiple quantum wells as an image processor chip to early vision processes. We focused our attention at the edge detection process using layouts of photodetectors to extract Laplacians of images. Laplacians of linear, constant, step, and Gaussian intensity profiles agree with the expected values. These results show that the device works properly as an edge detector. 相似文献
992.
A high piezoelectric transition temperature is indicated for present orthorhombic samples of lead meta-niobate (PbNb2O6) by the high value of the temperature (Tm) at which the real part (?′) of electrical permittivity peaks. It is 573 to 580°C. The imaginary component (?″) increases sharply at these temperatures. Cooling run after heating to 700°C gives changed values of ?′ and ?″ and Tm. Present work reports impedance spectroscopy (up to 700°C over 20 Hz to 5.5 MHz) and Differential Scanning Calorimetry or DSC on the pure orthorhombic phase, and, for the first time, on the pure rhombohedral phase. DSC shows an endothermic dip across Tm during heating and an exothermic peak during cooling for the orthorhombic sample only. 相似文献
993.
994.
This paper presents an electronic system for a fast DNA label-less detection. The sensitivity of the capacitive sensor in use is improved by depositing an insulating self-assembled monolayer (SAM) over the golden electrodes. The capacitance shift due to the hybridization effect is monitored by means of a charge-sensitive amplifier and digitalized by means of a comparator and a counter. The read-out solution demonstrates the ability to identify a 0.01% variation on the capacitive value of the sensor. Results from measurements with the optimized sensor show the reliability of the electronics. The investigated solution is suitable for monolithic systems or for a micro-fabricated array of sensors. An example of the integrated front-end is described and performances and noise evaluation are reported here. 相似文献
995.
Heidi Van den Broeck Hans De Wolf Ronny Blust 《The Science of the total environment》2009,407(8):3063-3069
In this study we present the results of an intersex survey of Littorina littorea along the Belgian coast. Levels of female intersex and sterility were determined to assess TBT related adverse effects. In addition, we determined the levels of male penis shedding and trematode infestation and investigated the morphology of the shell. Significant differences were found for all these variables which clearly differentiated periwinkles from Zeebrugge (B2) from those at other locations. Intersex index (ISI) values were relatively low (i.e. 0.00-0.39), except at B2 where they ranged up to 3.52, the highest value ever reported in literature. Consequently, female reproductive impairment at B2 was severe. Indeed, up to 95% of female periwinkles were sterile at B2. In addition, 61% of the male periwinkles had shed their penis. Furthermore, no trematode infestation could be detected at B2 and specimens from this location had the largest and heaviest shells, which may be related to population demography and/or a different use of energy budgets. 相似文献
996.
Antonella De Angeli 《AI & Society》2009,24(3):213-223
This paper reports two studies investigating the role of culture on the design and personalisation of virtual spaces. The
first study was a systematic analysis of 60 MSN virtual spaces belonging to British and Chinese students. The analysis concentrated
on design patterns and communication style. The second study was an on-line survey designed to compare the relative importance
of cultural values and personality traits on self-reported behaviour with, and preferences for, virtual space design. Results
highlighted the importance of culture on design and communication in virtual spaces. Implications for interaction design are
discussed. 相似文献
997.
Kristof De Witte Rui C. Marques 《International Transactions in Operational Research》2009,16(2):257-271
Environmental factors add complexity to the comparison between specific activities or entire entities. Decision making units with an inferior performance are tempted to invoke that their organization is "different" from the others in the data set. By reinterpreting and extending the metafrontier literature, we propose an all-embracing concept to fully capture the operational environment. We suggest the "Group Specific Technical Efficiency" as a new measure to assess the overall efficiency of a utility while allowing for environmental differences. A real-world example of drinking water utilities from five different countries illustrates the concept. 相似文献
998.
Ans De Roeck Thomas DuvetterIlse Fraeye Iesel Van der PlanckenDaniel Ndaka Sila Ann Van LoeyMarc Hendrickx 《Food chemistry》2009
Heat sterilization of plant derived food products entails considerable organoleptic and nutritional quality losses. For instance, texture loss of fruits and vegetables occurs, next to turgor pressure losses, mainly due to chemical changes in the cell-wall pectic polysaccharides. High-pressure sterilization, i.e. the combination of high temperature (?90 °C) with high pressure (?500 MPa), could present a positive alternative assuring safety while minimizing quality losses. In this study, the potential of high-pressure sterilization in preserving fruit and vegetable texture was evaluated by investigating the effect of combined high-pressure/high-temperature (HP/HT) treatments on two texture related chemical pectin conversions in model sytems. First, a protocol was developed to perform reproducible kinetic studies at HP/HT under constant processing conditions. Subsequently, apple pectin solutions at pH 6.5 were subjected to different HP/HT combinations (500, 600 and 700 MPa/90, 110 and 115 °C) and the extent of chemical demethoxylation and β-eliminative depolymerization was determined. At atmospheric pressure, both zero-order reaction rate constants increased with increasing temperature. At all temperatures, demethoxylation showed a higher rate constant than β-elimination. However, a temperature rise resulted in a stronger acceleration of β-elimination than of demethoxylation. When combining high temperature with high pressure, β-elimination was retarded or even stopped, whereas demethoxylation was stimulated. These results are very promising in the context of the texture preservation of high-pressure sterilized fruits and vegetables, as β-elimination is accepted to be one of the main causes of thermal softening and low methoxylated pectin can enhance tissue strength by forming cross-links with calcium ions present. 相似文献
999.
新型墙体材料的现状与展望 总被引:6,自引:0,他引:6
介绍了我国目前墙体材料的生产与应用状况,分析了新型墙体材料的技术应用政策和应用前景,评述了新型墙体材料的优越性,介绍生产新型墙体材料的原材料和设备,提出了新型墙体材料及其砌体结构存在和应解决的问题,为新型墙体材料在建筑业中的推广应用提供部分资料。 相似文献
1000.
Steven Latré Antonio Liotta Filip De Turck 《Journal of Network and Systems Management》2014,22(2):280-288
The first IFIP/IEEE international workshop on quality of experience (QoE) centric management (QCMan 2013) was held on May 31, 2013 in Ghent, Belgium. This report summarizes the keynotes, presentations and discussions in QCMan 2013 and provides a high-level view of ideas, challenges, strategies and the current state of the research activities in the field of QoE management. 相似文献