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101.
何琴琴 《轧钢》2019,36(3):51-58
以Orbit专利分析平台为主要研究工具,从专利文献中抽取专利数量指标和专利质量指标来构建评价薄板坯连铸连轧技术竞争力和企业创新能力的指标体系,结合其他文献研究的成果,从产业发展的实际出发做出分析,系统揭示了自薄板坯连铸连轧技术开发以来的技术进步、专利布局、发展演化、国内外发展现状、技术竞争实力等,有助于在专利文献提供的线索启发下开发新产品、新技术,从而有效提高研发效率。  相似文献   
102.
Thermal flow characteristics and the methane conversion reaction in a low power arc plasma reactor for efficient storage and transport of methane, which is the main component of shale gas, were simulated. The temperature and velocity distributions were calculated according to the type of discharge gases and arc current level by a self-developed magnetohydrodynamics (MHD) code and a commercial ANSYS-FLUENT code; the transport of chemical species was analyzed as including the chemical reactions of methane conversion. The simulated results were verified by the comparison of calculated and measured arc voltages with permissible low error as under 4%. Three C2 hydrocarbon gases with ethane (C2H6), ethylene (C2H4), and acetylene (C2H2) were selected as the converted species of methane from experimental data. The mass fraction of C2 hydrocarbons and hydrogen as the product of the conversion reaction at the reactor was also calculated. Those values show good agreement with the actual experimental results in that the major conversion reaction occurred in C2H2 and hydrogen, and the conversions to C2H6, C2H4, and hydrogen were minor reactions of methane pyrolysis conversion.  相似文献   
103.
Visual data analysis can be envisioned as a collaboration of the user and the computational system with the aim of completing a given task. Pursuing an effective system‐user integration, in which the system actively helps the user to reach his/her analysis goal has been focus of visualization research for quite some time. However, this problem is still largely unsolved. As a result, users might be overwhelmed by powerful but complex visual analysis systems which also limits their ability to produce insightful results. In this context, guidance is a promising step towards enabling an effective mixed‐initiative collaboration to promote the visual analysis. However, the way how guidance should be put into practice is still to be unravelled. Thus, we conducted a comprehensive literature research and provide an overview of how guidance is tackled by different approaches in visual analysis systems. We distinguish between guidance that is provided by the system to support the user, and guidance that is provided by the user to support the system. By identifying open problems, we highlight promising research directions and point to missing factors that are needed to enable the envisioned human‐computer collaboration, and thus, promote a more effective visual data analysis.  相似文献   
104.
Pulses are processed in diverse ways prior to consumption. Soaking and germination are among the most common traditional, household-level food processing strategies. This study was carried out to determine the effects of soaking, germination, cooking and their combinations on the contents of selected nutrients and anti-nutrients of red dry bean and chickpea. In addition, the effects of pre-treatment on cooking time and the acceptability of dishes prepared from red dry bean and chickpea were determined. The nutrient compositions (zinc, iron and calcium) of most soaked-cooked and germinated-cooked red dry bean and chickpea samples were not significantly different than those of respective controls. However, soaking and germination pre-treatments significantly lowered the phytate and tannin contents of the red dry bean and chickpea samples, with a few exceptions, and overall, polyphenol contents were lower after soaking-cooking than after germination-cooking. Most scores for sensory attributes of bean-based and chickpea-based dishes prepared from soaked or germinated samples were not significantly different than those of the controls. For most red dry bean and chickpea samples, longer germination times yielded superior results in terms of reductions in cooking time, tannin content, and phytate:zinc and phytate:iron molar ratio.  相似文献   
105.
This paper presents a calculation method for obtaining the continuous variation in stress between the tip and the soil during dynamic penetration tests, particularly in the case of using the Panda 3® penetration testing device. The originality of the method is that the tip stress can be computed continuously throughout the driving process. For each impact of the hammer on the penetrometer, data are recorded by sensors located at the top of the apparatus. Then, the stress at the tip and the displacement of the apparatus are calculated with a method based on the propagation of waves in the device. A three-dimensional numerical model of the penetration test, based on the Panda 3® specifications and using the discrete element method (DEM), is proposed in this paper. The purpose of the simulations is to validate the calculation method by comparing the curves of the tip stress versus the penetration distance obtained in two different ways, the first being the distance directly observed at the tip and the second being the distance calculated from the data recorded at the top of the penetrometer, as with the experimental device. The entire apparatus is represented, including the hammer, the rod, and the tip, and is driven into the model soil. The calculation method is applied, and the results are compared to the actual response of the soil to the driving of the penetrometer directly at the tip, which can be obtained with the numerical model. The responses are found to be very similar, confirming the theoretical framework and its underlying assumptions. This method is applied to dynamic penetration tests and provides the opportunity to obtain mechanical parameters other than the tip resistance from the tests.  相似文献   
106.
In innovation and project management studies incremental development projects are perceived as theoreticlly and organisationally uninteresting. By means of a longitudinal study of product improvement projects at an automobile firm, this paper challenges such views and shows how the cumulative impact of the studied sequence resulted in a competitive repositioning of the company's product portfolio during a financially difficult period. Project managers achieved this by transcending the separation between exploration and exploitation projects; they not only adhered to time, cost and quality goals but also tried out new ways of testing and experimenting with controversial technical ideas. The paper analyzes the intensive inter project learning that generated these ambidextrous capabilities and emphasizes that practices at the project-level need to be buttressed by expanded management learning and capability development also at the sequence level.  相似文献   
107.
Sc3+ substituted M-type ferrites are effective microwave magnetic materials with a ferromagnetic resonance frequency in the range of 20 GHz–50 GHz. We report on the fabrication of oriented ferrite thick films as microwave components for application in the Ka-band at 30 GHz. Films of BaFe11.5.Sc0.5O19 were prepared by screen-printing on alumina substrates, drying in an external magnetic field, and sintering at 900 °C. Low-temperature sintering is achieved through use of a mixed BBSZ/CuO sintering aid. A strong anisotropy of the sintered ferrite films is revealed by XRD analysis. Microwave properties of the films were determined in a coplanar waveguide setup. The ferromagnetic resonance frequency of the films is at 30 GHz and the textured films possess good nonreciprocal properties which scale with film thickness. The films were tested in a Y-junction circulator, and represent promising materials for self-biased microwave components fabricated in thick film technology.  相似文献   
108.
In this work, we report the tuning effect of the Si substitution on the magnetic and high frequency electromagnetic properties of R2Fe17 compounds and their paraffin composites. It is found that the introduction of Si can remarkably improve the magnetic and electromagnetic properties of the R2Fe17 compounds, making the R2Fe17–xSix-paraffin composites excellent microwave absorption materials (MAMs). By introducing the Si element, their saturation magnetizations decrease slightly, while much higher Curie temperatures are obtained. Furthermore, better impedance match is reached due to the decrease of the high-frequency permittivity ε′ by about 40%–50%, which finally enhances the performance of the microwave absorption. The peak frequency (fRL) of the reflection loss (RL) curve moves toward high frequency domain and the qualified bandwidth (QB, RL ≤ ?10 dB) increases remarkably. The maximum QB of 3.3 GHz (12.0–15.3 GHz) is obtained for the Sm1.5Y0.5Fe15Si2-paraffin composite (d = 1.0 mm) and the maximum RL of ?53.6 dB is achieved for Nd2Fe15Si2-paraffin composite (d = 2.2 mm), both surpassing most of the reported MAMs. Additionally, a distinguished dielectric microwave absorption peak is observed, which further increases the QB in these composites.  相似文献   
109.
Two kinds of Cu-Al_2O_3 composites(with and without La) were prepared via mechanical alloying-spark plasma sintering(MA-SPS) method. Microstructure, mechanical properties and electrical resistivity were investigated systematically using metallography, scanning electron microscopy, transmission electron microscopy, mechanical and electrical properties testing. The results indicate that an appropriate amount of La can homogenize the distribution of Al_2O_3. As such, yield strength, ultimate tensile strength and elongation of Cu-Al_2O_3-La are greatly increased. Some semi-coherent interface between Cu and Al_2O_3 is found, which means a low interface energy. The grain shape of Cu changes to irregular band with the addition of La. This change results in a density decrease of grain boundary and reduces electrical resistance. Lanthanum may exist in the form of La_2O_3.  相似文献   
110.
孙超凡  方圆  王雅晴  刘伟  潘宏伟 《钢铁》2019,54(7):83-87
 为研究卷取温度对超低碳T-3 CA中第二相粒子析出行为的影响,采用金相、TEM等检测手段,分析了580、630、680 ℃ 3个典型卷取温度下超低碳T 3 CA中第二相粒子的析出特性,结果发现卷取温度越高,热轧形成的TiC粒子尺寸越粗大,分布越稀疏。结合相关动力学计算分析了卷取温度对TiC粒子沉淀析出时临界晶核尺寸、相对形核率、相对沉淀析出时间的影响。结果表明,随着卷取温度由580提高到680 ℃,TiC粒子沉淀析出时临界晶核尺寸增大约1.0 nm,相对形核率降低约1.0个数量级,相对沉淀析出孕育时间增大约0.8个数量级。  相似文献   
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