直接凝固注模成型Si_3N_4及SiC陶瓷──基本原理及工艺过程

直接凝固注模成型（ｄｉｒｅｃｔｃｏａｇｕｌａｔｉｏｎｃａｓｔｉｎｇ，ＤＣＣ）是一种崭新的（准）净尺寸陶瓷成型方法。本文报道了采用此法成型Ｓｉ_３Ｎ_４及ＳｉＣ陶瓷的基本原理和工艺过程。ＤＣＣ成型工艺过程为把高固相含量低粘度的陶瓷浆料浇注到无孔模具中，事先加入到浆料中的生物酶及化学物质通过改变浆料的ｐＨ或电解质浓度来改变浆料的胶体化学行为，从而使浆料原位凝固，得到有足够脱模强度的陶瓷坯体。ＤＣＣ成型的特点为坯体密度高（理论密度的５５％～７０％），坯体均匀，不用或只需少量的有机添加剂（少于１％），可成型大尺寸、复杂形状、高可靠性的陶瓷部件。     

基于螺旋搜索机制的行星搜索算法

螺旋搜索机制的全局搜索能力强,广泛用于萤火虫算法及鲸鱼搜索算法,但其收敛速度慢,收敛精度低,局部搜索能力较差。通过改变收敛范围较小时的搜索模式,提出了局部螺旋搜索来提高其局部搜索能力,并引入变异操作提高其局部搜索能力,提出了行星搜索算法。通过对单峰及多峰值测试函数对该算法进行验证。结果表明行星搜索算法在收敛速度、搜索精度及局部搜索能力等方面较粒子群算法、萤火虫算法及鲸鱼搜索算法等有明显提升。     

CO2压缩机增速齿轮箱断齿故障分析

通过对齿轮断口的形貌、振动原因及裂纹源分析、并结合对原齿轮设计承裁能力的校核，找到了GN-25增速齿轮箱断齿的原因，提出了防止故障发生措施。     

Users’ interest grouping from online reviews based on topic frequency and order

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.     

CAU9901的高效液相色谱分析

报道了新型植物生长调节剂CAU9901的高效液相色谱分析方法。该方法快速简捷,精密度变异系数为0.49%,相关系数为1.000 4,准确度回收率在98.89%~100.1%之间。     

5-烷基-2-氨基-1,3,4-噻二唑的合成及应用

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     

Numerical Simulation of Oil‐water Hydrocyclone Using Reynolds‐Stress Model for Eulerian Multiphase Flows

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.     

使用KQ-1缓蚀阻焦剂,减轻糠醛装置腐蚀和结焦

独山子炼油厂糠醛精制装置设备腐蚀状况严重 ,尤其是加工高酸值原料 ,更加剧了设备的腐蚀。通过对腐蚀原因分析 ,决定从工艺防腐上解决 ,提出了加入缓蚀剂减缓设备腐蚀的方法 ,在实验室评价和工业装置中 ,评选了四种糠醛精制装置的缓蚀剂 ,其中KQ 1作为装置缓蚀剂效果最佳 ,平均缓蚀率达到 4 4 .5 % ,并估算了KQ 1工业使用的经济效果     

Manipulating the microstructure and rheology in polymer‐organoclay composites

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 T_m 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 T_m), 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.     

影响株洲火车站广场空气质量的因素研究

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。