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61.
Large volume of online review data can reveal consumers’ major interests on domain product, which attracts great research interests from the academic community. Most of the existing works focus on the problems of review summarization, aspect identification or opinion mining from an item’s point of view such as the quality or popularity of products. Considering the fact that users who generate those review texts draw different attentions to product aspects with respect to their own interests, in this article, we aim to learn K users’ interest groups indicated by their review writings. Such K interest groups’ identification can facilitate better understanding of major and potential consumers’ concerns which are crucial for applications like product improvement on customer-oriented design or diverse marketing strategies. Instead of using a traditional text clustering approach, we treat the groupId/clusterId as a hidden variable and use a permutation-based structural topic model called KMM. Through this model, we infer K interest groups’ distribution by discovering not only the frequency of product aspects (Topic Frequency), but also the occurrence priority of respective aspects (Topic Order). They jointly present an informative summarization on the raw review corpus. Our experiment on several real-world review datasets demonstrates a competitive solution. 相似文献
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63.
5-烷基-2-氨基-1,3,4-噻二唑的合成及应用 总被引:16,自引:1,他引:16
用硫代氨基脲与甲酸、乙酸、丙酸、丁酸、异丁酸、异戊酸等在盐酸、磷酸、多聚磷酸、硫酸催化下 ,分别合成了 2 -氨基 -1 ,3 ,4-噻二唑 (a)、5 -甲基 -2 -氨基 -1 ,3 ,4-噻二唑 (b)、5 -乙基 -2 -氨基 -1 ,3 ,4-噻二唑 (c)、5 -丙基 -2 -氨基 -1 ,3 ,4-噻二唑 (d)、5 -异丙基 -2 -氨基 -1 ,3 ,4-噻二唑 (e)、5 -异丁基 -2 -氨基 -1 ,3 ,4-噻二唑 (f)。并对工艺条件进行了试验 ,结果表明 :最佳工艺条件为硫代氨基脲与酸的摩尔比为 1∶ 1 .4,合成 2 -氨基 -1 ,3 ,4-噻二唑为多聚磷酸催化 ,合成其它的为浓盐酸催化 ,回流 3 h,产率分别为 96.78%、74.3 4%、73 .67%、71 .68%、68.44%、67.5 4%。同时以 a~f为原料合成了具有抗菌作用的 5 -烷基 -1 ,3 ,4-噻二唑硫脲乙酸和 5 -烷基 -2 -苯基 -硫脲 -1 ,3 ,4-噻二唑的衍生物 相似文献
64.
A three‐dimensional oil‐water turbulent flow and oil separation process in a double‐cone liquid‐liquid hydrocyclone (LLHC) is numerically simulated using FLUENT software. The Euler‐Euler approach and Reynolds‐stress model are combined and adopted in this simulation to handle the challenging situation of anisotropic turbulent two‐phase flow with a higher volumetric ratio (over 10%) in the dispersed phase. It is visualized well in the simulation how separation, aggregation and shift of oil and water proceed in the LLHC. The oil separation efficiency is determined based on flow field and phase concentration distribution. The simulation is verified by comparing predicted and measured separation efficiency in the LLHC. 相似文献
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66.
Michael Gelfer Carlos Avila‐orta Lizhi Liu Ling Yang Benjamin Chu Benjamin S. Hsiao Hyun H. Song Mayu Si Miriam Rafailovich Andy H. Tsou 《Polymer Engineering and Science》2002,42(9):1841-1851
A series of nanocomposites prepared by melt‐blending of cloisite‐based organoclays with poly(ethylene‐vinylacetate) (EVA) and neutralized poly (ethylene‐methacrylic acid) (EMA) copolymers were investigated via DSC, small‐angle X‐ray scattering (SAXS), and rheological techniques. SAXS results indicated partial clay exfoliation in all samples. In both EMA and EVA systems, the nominal melting temperature Tm and bulk crystallinity are not significantly affected by the presence of organoclays, suggesting that clay particles are predominantly confined in the amorphous phase. In rheological measurements (above Tm), the EVA‐clay system demonstrated a solid‐like rheological behavior under the small‐strain oscillatory shear, yet it was able to yield and flow under a steady shear, which is the characteristic of physical crosslinking. In contrast, the EMA‐clay system exhibited a melt‐like rheological behavior, where the influence of organoclay on the thermorheological behavior of the EMA composite was quite minimal. We propose that the carbonyl groups of vinylacetate in EVA interact with the clay surface, resulting in a strong physically crosslinking like interaction in the melt. On the other hand, the interaction between EMA and clay is weak because of repulsion between carboxyl anions and negatively charged clay surface. 相似文献
67.
为了探究影响火车站广场污染物(总悬浮颗粒物和可吸入颗粒物)质量浓度的因素,以株洲火车站广场为研究对象,对总悬浮颗粒物和可吸入颗粒物质量浓度与人流密度、车流量的变化关系进行了试验性研究。结果表明,总悬浮颗粒物质量浓度与人流密度、车流量都呈正相关,其主要影响因素是车流量;可吸入颗粒物质量浓度与人流密度呈正相关,与车流量不呈明显的正相关,其主要影响因素是人流密度。细菌和病毒以可吸入颗粒物为载体被人体吸入而致病,因此人们活动时应尽量避开广场人流密度大的地方。 相似文献
68.
磁致伸缩应变与磁场关系的非线性,影响了磁致伸缩控制元件的精度和稳定性。文章针对这一问题,在超磁致伸缩式微小型高速开关阀驱动部件设计基础上,提出了沿超磁致伸缩棒(GMM)轴向开槽的方法来改善GMM部件的工作性能。通过对轴向开槽前后GMM棒内部磁场强度和焦耳热分布的数值计算,分析了轴向开槽对改善磁场强度的分布和减少热损耗功率的影响,通过对GMM棒开槽前后伸缩量的测试,验证了开槽可以明显改善超磁致伸缩材料组件的非线性。 相似文献
69.
Zheng Peng Si‐Dong Li Mao‐Fang Huang Kui Xu Chen Wang Pu‐Wang Li Xiao‐Guang Chen 《应用聚合物科学杂志》2002,85(14):2952-2955
The thermal degradations of methyl methacrylate‐graft‐natural rubber (MG) at different heating rates (B) in nitrogen were studied by thermogravimetric analysis. The results indicate that the thermal degradation of MG in nitrogen is a one‐step reaction. The degradation temperatures increase along with the increment of heating rates. The temperature of initial degradation (T0) is 0.448B + 362.4°C, the temperature at maximum degradation rate, that is, the peak temperature on a differential thermogravimetric curve (Tp) is 0.545B + 380.7°C, and the temperature of final degradation (Tf) is 0.476B + 409.4°C. The degradation rate at Tp is not affected by B, and its average value is 48.9%; the degradation rate at Tf is not affected by B either, and its average value is 99.3%. The reaction order (n) is 2.1 and is not affected by B. The reaction activation energy (E) and the frequency factor (A) increase along with B, and the apparent reaction activation energy (E0) is 254.6 kJ/mol. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2952–2955, 2002 相似文献
70.
实验采用正交实验法和对比实验,通过对R2O-RO-AlO3-B2O3-SiO2系统的成釉机理分析及熔融特性、熔体的粘度和表面张力等性能的测试,探讨了该系统在骨质瓷中的应用。 相似文献