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71.
The thermodynamic behavior of Ce and its compounds in molten steel was summarized, and the types of stable compounds after Ce added to molten steel and its variation were predicted. The mechanisms and rules of Ce compounds and dissolves Ce refining solidification structure of as- cast steel were summarized respectively. The improvement of homogenous by Ce was analyzed and the reason of decrease of element segregation was summarized. At last, some problems were pointed out which had not been solved in the research of rare earth Ce to improve the microstructure and homogeneity of steel, and put forward the main directions of the future research in this field. 相似文献
72.
Response surface methodology was advantageously used to optimally immobilise a β-galactosidase from chick pea onto alkylamine glass using Box–Behnken experimental design, resulting in an overall 91% immobilisation efficiency. Analysis of variance was performed to determine the adequacy and significance of the quadratic model. Immobilised enzyme showed a shift in the optimum pH; however, optimum temperature remained unaffected. Thermal denaturation kinetics demonstrated significant improvement in thermal stability of the enzyme after immobilisation. Galactose competitively inhibits the enzyme in both soluble and immobilised conditions. Lactose in milk whey was hydrolysed at comparatively higher rate than that of milk. Immobilised enzyme showed excellent reusability with retention of more than 82% enzymatic activity after 15 uses. The immobilised enzyme was found to be fairly stable in both dry and wet conditions for three months with retention of more than 80% residual activity. 相似文献
73.
Visualization workflows are important services for expert users to analyze watersheds when using our HydroTerre end-to-end workflows. Analysis is an interactive and iterative process and we demonstrate that the expert user can focus on model results, not data preparation, by using a web application to rapidly create, tune, and calibrate hydrological models anywhere in the continental USA (CONUS). The HydroTerre system captures user interaction for provenance and reproducibility to share modeling strategies with modelers. Our end-to-end workflow consists of four workflows. The first is data workflows using Essential Terrestrial Variables (ETV) data sets that we demonstrated to construct watershed models anywhere in the CONUS (Leonard and Duffy, 2013). The second is data-model workflows that transform the data workflow results to model inputs. The model inputs are consumed in the third workflow, model workflows (Leonard and Duffy, 2014a) that handle distribution of data and model within High Performance Computing (HPC) environments. This article focuses on our fourth workflow, visualization workflows, which consume the first three workflows to form an end-to-end system to create and share hydrological model results efficiently for analysis and peer review. We show how visualization workflows are incorporated into the HydroTerre infrastructure design and demonstrate the efficiency and robustness for an expert modeler to produce, analyze, and share new hydrological models using CONUS national datasets. 相似文献
74.
75.
In (organic) spin-valve devices, two ferromagnetic electrodes having different coercive fields are used to achieve an anti-parallel configuration necessary to enforce spin-flip of electrons within the semiconductor spacer layer. Here we report a use of immobilized magnetic organic molecules as spin-injection and spin-detection layers to form pre-fabricated spin-valve devices. While immobilized manganese- and nickel-phthalocyanines were used as spin-injection and spin-detection layers both, copper phthalocyanine acted as the spacer layer in the all-organic spin-valve devices.In the current-voltage characteristics of parallel and anti-parallel configurations, the electrical resistance was always higher for the latter one implying positive magnetoresistance in the material. By lowering thickness of the spacer layer down to a monolayer region, a tunneling regime could be achieved; spin-flip process in organic spin-valves has been found to be facile in the tunneling regime as compared to that during the spin-transport process through a thicker spacer layer. 相似文献
76.
Animated pedagogical agents (APAs) have frequently been used as a powerful addition to learning environments, since APAs have been known to facilitate learning. APAs can present various features, such as voice, movements, gestures and pointing, and researchers have sought to verify specifically which features of agents effectively contribute to learning. Previous studies have studied these features by comparing different degrees of agent embodiment in the evaluation of the image effect (i.e., students learn more when learning systems have visual APAs), the embodied agent effect (i.e., fully embodied agents that deliver instruction aurally and use gestures to improve learning outcomes in text-only learning systems), the modality effect (i.e., oral instruction contributes to the learning process), and the expressiveness effect (i.e., fully embodied agents promote more effective learning than static ones). Some of these studies have investigated the image, embodied agent and modality effects in the same learning environment, but they were not the same studies that investigated the expressiveness effect. The expressiveness effect allows us to separate the movements of the agent from its other features, such as the agent's image, so investigating this effect is as important as investigating the other effects. We are not aware of any studies that investigated all of these four effects within the same learning system, nor that evaluated any of these effects in language learning environments. Accordingly, this paper describes the design, implementation, and analysis of an APA designed to evaluate the abovementioned effects. The APA was integrated into a computer-assisted language learning (CALL) system to teach English as a foreign language to Brazilian students. A total of 72 Brazilian undergraduate students were divided into four groups, each of which used a different version of the APA in the same CALL system: no agent, a voice-only agent, a static agent, or a fully embodied agent. We compared students’ gain scores (i.e., difference between pre- and posttest scores) across groups to evaluate each of the four effects. Though the outcomes of our study supported the presence of the embodied agent and modality effects, we were not able to demonstrate the image or expressiveness effects in the experiment. Our results indicate that the voice of the agent might contribute more positively to learning than movements, gestures and pointing. 相似文献
77.
Guilherme Wisnik 《Architectural Design》2016,86(3):20-27
An awakening interest in public space in Brazilian cities is emphasising the value of existing civic areas. Guilherme Wisnik , a critic, curator and professor at the Faculty of Architecture and Urbanism of the University of São Paulo, looks at the history and potential future of Brazil's urban spaces. He highlights how despite the introduction of innovative Modernist design in the mid-20th century, which forged ‘a new relationship between architecture, urbanism and landscape design’, more recently the country's cities have been subject to the vicissitudes of market and political forces. 相似文献
78.
立足资源、面向市场、强化差异性竞争成为中国西部城镇重要发展途径.风景区边缘城镇由于毗邻稀缺的风景名胜资源的区位优势,迫切希望依托风景区带动地方全面发展,事实上却存在开发与保护冲突、景镇建设脱节的现象,其核心矛盾在于景区与城镇定位不明、资源配置不利、产业发展脱节.基于可持续发展理念提出景镇统筹发展思路,其核心包括生态环境保护优先、产业经济统筹发展、空间景观整体塑造、社会生活和谐共荣.最后以重庆统景规划为例,构建以空间、风貌、旅游、地产四大板块为基础的景镇统筹发展整体框架,实现生态安全保障、经济高度发展、三大效益高度统一的发展目标. 相似文献
79.
矿产资源资产化管理研究 总被引:1,自引:0,他引:1
针对我国矿产资源管理现状中存在的弊端,论述了实行矿产资源资产化管理的必然性以及对策。 相似文献
80.