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91.
92.
Distance learning can solve the limitations of time and space in learning. However, due to the distance, teachers cannot manage students learning behaviors, i.e. they do not know whether a student is attentive, drowsy or absent. Teachers can overcome difficulties in students’ management by knowing the affective states of the students. This study adopts image recognition to capture face images of students when they are learning, and analyzes their face features to evaluate their affective states by fuzzy integrals. Test results indicate that the bad affective states are accurately identified. Teachers can monitor the students’ affective states from the detection results on the system interface. 相似文献
93.
Yung-Hsien Wu Chih-Ming Chang Chun-Yao Wang Chien-Kang Kao Alex Ku 《Microelectronic Engineering》2009,86(1):33-36
As the first step of DRAM manufacture, preanneal process plays an important role in determining the threshold voltage variation. It is found that the higher trans-1,2-dichloroethene flow in pad oxide growth and the higher nitrogen flow in high-temperature annealing step would respectively engender a lower boron segregation coefficient and higher nitridation of the oxide, both modify the boron distribution in the substrate and consequently the behavior of the threshold voltage. As the feature size of DRAM devices enter nanometer regime, besides gate oxidation, ion implantation and related thermal processes, the impact of preanneal process condition should be prudentially taken into consideration for rigorous control of the threshold voltage in the advanced DRAM production. 相似文献
94.
Danjela Kuščer Miha Skalar Janez Holc Marija Kosec 《Journal of the European Ceramic Society》2009,29(1):105-113
We have investigated the processing of 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN–PT) thick films on platinised alumina substrates. Nanosized PMN–PT powder with 2 mol% of excess PbO was prepared by high-energy milling and deposited on the substrate using screen-printing technology. The films were then sintered at 950 °C in a PbO-rich atmosphere. The influence of the sintering time and the amount of PbO-containing packing powder was studied and related to the structural, microstructural, dielectric and piezoelectric properties of the film. In order to obtain a homogeneous and dense thick film without any secondary phase, the PMN–PT films had to be sintered in the presence of a PbO-based liquid phase that had to be completely removed from the thick film during the final stage of the sintering. Under optimal sintering conditions we obtained a room temperature relative dielectric permittivity of 3600, dielectric losses of 0.036, a Tm of 174 °C, a permittivity at the Tm of 21,000 and a d33 of 140 pC/N. 相似文献
95.
Ultrasound-modulated optical tomography based on the measurement of laser-speckle contrast was investigated. An ultrasonic beam was focused into a biological-tissue sample to modulate the laser light passing through the ultrasonic column inside the tissue. The contrast of the speckle pattern formed by the transmitted light was found to depend on the ultrasonic modulation and could be used for imaging. Variation in the speckle contrast reflected optical inhomogeneity in the tissue. With this technique, two-dimensional images of biological-tissue samples of as much as 25 mm thick were successfully obtained with a low-power laser. The technique was experimentally compared with speckle-contrast-based, purely optical imaging and with parallel-detection imaging techniques, and the advantages over each were demonstrated. 相似文献
96.
Counter to the "start high, end high" effect of anchors in individual judgments and dyadic negotiations, 6 studies using a diverse set of methodologies document how and why, in the social setting of auctions, lower starting prices result in higher final prices. Three processes contribute to this effect. First, lower starting prices reduce barriers to entry, which increase traffic and generate higher final prices. Second, lower starting prices entice bidders to invest time and energy (creating sunk costs) and, consequently, escalate their commitments. Third, the traffic generated by lower starting prices can lead bidders to infer value in the item, thereby explaining previous findings that traffic begets more traffic. The authors show that barriers to entry that limit traffic (e.g., a misspelled brand name) lead to anchoring's normal assimilative effect rather than its reversal. By broadening the understanding of anchors to extended social interactions and open markets, the authors identify when and why starting prices anchor. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
97.
粒子群优化算法的发展与展望 总被引:17,自引:1,他引:17
对粒子群优化算法的产生背景、基本算法、改进算法、研究热点及应用领域作了简要的综述,并对其发展方向作了展望。 相似文献
98.
The dissolution of ozone and the decomposition of 2-chlorophenol were noticeably enhanced for experiments conducted in the fixed packed contactor than those conducted in a bubble column. The rate of ozone transfer was increased with the increasing amount of Pall rings contained in the packed contactor and the decreasing gas/liquid ratio (G/L) because the gas–liquid interface may be renewed effectively. The decomposition of 2-chlorophenol by ozonation was found to be faster for experiments conducted in alkaline solutions while the decomposition of total organic carbon only slightly enhanced. However, the decomposition of total organic carbon only slightly increased for experiments conducted in alkaline solutions. 相似文献
99.
We address several problems concerning the geometry of the space of Hermitian operators on a finite-dimensional Hilbert space, in particular the geometry of the space of density states and canonical group actions on it. For quantum composite systems we discuss and give examples of entanglement measures. 相似文献
100.
Zimmermann R. Wei-Shinn Ku Haojun Wang Zand A. Bardet J.-P. 《Internet Computing, IEEE》2006,10(5):26-33
Web services can help facilitate the exchange and utilization of geotechnical information. Such data is of critical interest to a growing number of municipal, state, and federal agencies as well as private enterprises. However, the lack of service infrastructures among heterogeneous data sources operating under different administrative controllers hampers the full use of geotechnical information. This article describes a Web-services-based way to manage geotechnical data via XML. 相似文献