Stability of C60 chains: molecular dynamics simulations

A linearly aligned structure of three C60 fullerene, interconnected by two benzorods of same size, have been investigated under heat treatment. The overall structure resembles a section of a beaded string. Nine different lengths of benzorods have been considered, and the effect on the thermal stability have been investigated by means of molecular dynamics method. It has been found that the structure is thermally stable up to elevated temperatures, and the linear alignment of the structure is persistent, up to the temperature of decomposition.     

基于注意力机制的文本情感倾向性研究

社交媒体上短文本情感倾向性分析作为情感分析的一个重要分支,受到越来越多研究人员的关注。为了改善短文本特定目标情感分类准确率,提出了词性注意力机制和LSTM相结合的网络模型PAT-LSTM。将文本和特定目标映射为一定阈值范围内的向量,同时用词性标注处理句子中的每个词,文本向量、词性标注向量和特定目标向量作为模型的输入。PAT-LSTM可以充分挖掘句子中的情感目标词和情感极性词之间的关系,不需要对句子进行句法分析,且不依赖情感词典等外部知识。在SemEval2014-Task4数据集上的实验结果表明,在基于注意力机制的情感分类问题上,PAT-LSTM比其他模型具有更高的准确率。     

On the generality of the part-set cuing effect: Evidence from nonmemory tasks.

A puzzling finding in memory research is that part–set cuing, or the presentation of some of the to-be-recalled items as cues, impairs recall of the remaining items. In this article a series of four experiments involving nonmemory tasks extends this finding to other cognitive domains. Specifically, it is shown that providing possible responses impairs the production of other responses when words are constructed from the letters of a lengthy word (Experiment 1), when differences between almost identical pairs of pictures are discovered (Experiment 2), when blurred pictures brought gradually into focus are identified (Experiment 3), and when nonsense figures are likened to meaningful objects or scenes (Experiment 4). These findings suggest that the part–set cuing effect in memory may be only one instantiation of a much broader phenomenon. And such a perspective might elicit a more satisfactory explanation of this puzzling effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thoughening of poly(lactic acid) with silicone rubber

In this study, poly(lactic acid) (PLA) was blended with silicone rubber (SR) to improve its impact strength and toughness by using dynamic crosslinking in the presence of peroxide during melt compounding. The SR to PLA ratio, peroxide and coagent concentrations were taken as experimental parameters. Blends were evaluated in terms of their thermal properties, tensile and impact strengths, dynamic mechanical properties, and micro‐structure. Results showed that PLA was successfully toughened with SR using dynamic crosslinking. Impact strength and energy of fracture in tensile test improved up to 4 and 10 times, respectively. On the other hand, yield strength and stiffness of blends deteriorated by the incorporation of SR. Thermal analysis pointed out that presence of SR decreased the cold crystallization temperature. It was observed from scanning electron microscopy (SEM) that the energy absorbing mechanism under impact loads in PLA/SR blends is tortuosity in the crack patterns. POLYM. ENG. SCI., 54:2029–2036, 2014. © 2013 Society of Plastics Engineers     

基于分布式框架的互动服务渠道运营平台优化设计

围绕“互动服务渠道的统一接入与认证,为客户提供智能化、多样化的服务,支撑互动服务运营以及新互动服务需求”的建设目标,从客户交互数据采集范围、营销活动策划应用、渠道运营监控分析能力、平台性能优化4个方面开展渠道协同运营平台优化完善,提高互动服务渠道建设和运营工作水平。     

Simulation of serrated chip formation in micro-milling of titanium alloy Ti-6Al-4V using 2D elasto-viscoplastic finite element modeling

Finite element simulations have been utilized in analyses of machining process for several decades. In mechanical micromachining, finite element simulation can also be used for predicting cutting forces, minimal chip thickness, temperatures, and tool wear. The accuracy of results and the computational cost are highly dependent upon the assumptions which govern that particular chip formation problem. This study presents a comparison of two different material assumptions in finite element simulation of micro-milling titanium alloy Ti-6Al-4V. The same simulation was conducted by using the elasto-viscoplastic and the viscoplastic material assumptions. The predicted results are compared against the experimental observations. The results have shown that the material assumption has a major effect on the mechanism of chip formation and heat generation but a minor effect on the cutting force and tool wear prediction. In terms of computational cost, it was found that the simulation with the viscoplastic material assumption can reduce simulation time up to eight times that of required for a simulation with elasto-viscoplastic assumption.     

Subcooled Flow Boiling Over Microstructured Plates In Rectangular Minichannels

Microstructures offer enhancements in boiling heat transfer by increasing bubble departure frequency, active nucleation site density, critical cavity size, and surface area. Integration of microstructures to surfaces alters significant surface parameters such as porosity of the microstructured plates, contact angle, and configuration of microstructures on the surface, which all affect boiling heat transfer. The goal of this study is to investigate boiling heat transfer on different microstructured plates and the effect of various microscale surface morphologies on boiling heat transfer. The microstructured surfaces were formed on aluminum alloy 2024 sheets with the use of a simple and environmentally friendly technique of random mechanical sanding (grits of #36, #60, #400, and #1,000). Distilled water was pumped using a micro gear pump to the rectangular minichannel test section at flow rates of 100, 180, and 290 ml/min, which correspond to mass fluxes of 5.46, 10.58, and 16.15 kg/m².s, respectively. It was observed that surfaces with low grit (grit #36) showed no considerable enhancement, whereas the use of higher grit counts considerably enhanced boiling heat transfer up to a critical grit count. The results were supported by the images from the performed visualization of flow boiling.