A STUDY OF THE HIGH PRESSURE POLYETHYLENE TUBULAR REACTOR

As an example of the free radical polymerization reactor we have conducted a theoretical study of the high pressure polyethylene tubular reactor with cooling from the jacket. The plug flow model including the axial dispersion is considered with as well as without the steady state assumption for the active intermediates. We observe that the axial dispersion has negligible effect on the reactor performance and that the steady slate assumption is quite reasonable. The performance of the reactor is characterized by the exit monomer conversion, the peak temperature and the number and weight average degrees of polymerization, and the effects of various operating conditions are extensively investigated. Finally, an optimal temperature policy that would maximize the exit monomer conversion is determined by means of the Maximum Principle.     

碳纤维及其复合材料的研究应用进展

介绍了碳纤维及其增强复合材料的特性，着重阐述了碳纤维增强树脂基复合材料中基体。的分类、选择和应用，指出了碳纤维及其复合材料进一步发展应用的前景。     

江苏圣奥推出TMQ新品

<正>11月25～27日,江苏圣奥化学科技有限公司(简称"江苏圣奥")高调亮相第四届亚洲埃森轮胎展暨第十届中国国际橡胶技术展览会。作为世界领先的橡胶助剂专业供应商,江苏圣奥在展会     

烟草花叶病毒病的分子鉴定

为了建立烟草病毒病的分子鉴定体系,采用TMV,CMV和PVY3种病毒的检测引物对烟草花叶病样品进行了RT-PCR扩增,并从核酸水平上对病毒基因序列进行了分析。RT-PCR鉴定结果显示,该病害病原为TMV,测序结果显示扩增产物长923bp,序列比对后发现该序列与TMV3个中国分离物的同源性高达97%,序列分析结果表明该段序列位于TMV基因组3'末端,包含部分MP基因、完整CP基因和3'端非编码区。对CP基因进行了系统进化分析,且该序列已成功登陆GenBank。     

烟草中啶虫脒、吡虫啉残留量的UPLC-MS/MS测定

用乙酸-乙腈提取,基质固相萃取净化,UPLC/MS/MS法测定了31个烤烟烟叶样品中的啶虫脒、吡虫啉残留量。结果表明:①方法的检测限吡虫啉、啶虫脒均为0.01mg/kg,啶虫脒回收率在91.6%～102.5%,相对标准偏差为3.59%～4.52%,吡虫啉回收率在90.1%～102.1%,相对标准偏差为3.85%～4.47%;②烟叶样品中啶虫脒检出率约为1/5,检出量15.5～243.1μg/kg;吡虫啉检出率约1/4,检出量22.4～179.5μg/kg。     

区域环境对卷烟主流烟气化学特性和感官质量的影响

为了研究区域环境对卷烟烟气化学特性和感官质量的影响,分别在广州、河南省安阳、沈阳和云南省玉溪的自然环境条件下抽吸"双喜"牌卷烟样品,分析了其主流烟气的常规化学指标和香味成分,同时还进行了感官评价。结果表明:①在广州抽吸,烟气焦油量最高,pH最低;在玉溪抽吸,烟气焦油量最低,水分和pH最高;在沈阳抽吸,烟气水分最低;在这4个城市抽吸,烟气烟碱量基本一致;②与广州相比,在安阳和沈阳抽吸,卷烟主流烟气中小分子香味成分释放量普遍增大,而大分子香味成分释放量减小;在玉溪抽吸,卷烟主流烟气中小分子香味成分释放量虽有变化,但规律性不明显,而大分子香味成分释放量普遍降低;③与广州相比,在安阳抽吸,卷烟烟气的刺激性增大;在沈阳抽吸,烟气的细腻度、舒适度和刺激性变差;在玉溪抽吸,香韵有所改变。     

烟包喷码图像自动检测控制系统的设计与应用

在卷烟包装过程中,喷码机连续喷码时会出现数码漏喷、模糊、缺字、移位等现象,而卷烟包装机无法将不合格喷码烟包剔除。为此设计了烟包喷码图像自动检测控制系统,该系统利用智能照相机采集喷印在包装膜上的数码,对采集到的数码进行智能化处理判断,并将检测结果信号传送至PLC控制系统,对不合格喷码烟包进行剔除。ZB43硬盒包装机安装烟包喷码图像自动检测控制系统后,实现了对烟包防伪数码的实时检测,能够及时发现喷码不合格烟包并进行报警和剔除,喷码不合格烟包返修频次由每月约12次/台减少为0次,喷码不合格烟包剔除率达到了99%以上,保证了卷烟产品质量。     

Extracting Regularities in Space and Time Through a Cascade of Prediction Networks: The Case of a Mobile Robot Navigating in a Structured Environment

We propose that the ability to extract regularities from time series through prediction learning can be enhanced if we use a hierarchical architecture in which higher layers are trained to predict the internal state of lower layers when such states change significantly. This hierarchical organization has two functions: (a) it forces the system to recode sensory information progressively so as to enhance useful regularities and filter out useless information; and (b) it progressively reduces the length of the sequences which should be predicted going from lower to higher layers. This, in turn, allows higher levels to extract higher-level regularities which are hidden at the sensory level. By training an architecture of this type to predict the next sensory state of a robot navigating in an environment divided into two rooms, we show how the first-level prediction layer extracts low-level regularities such as 'walls', 'corners' and 'corridors', while the second-level prediction layer extracts higher-level regularities such as 'the left side wall of the large room'. The extraction of these regularities allows the robot to localize its position in the environment and to detect changes in the environment (e.g. the presence of a new object or the fact that a door has been closed).