基于粒子群理论的板形模糊模式识别方法

带钢板形的模式识别是板形闭环控制的关键环节,板形模式的识别结果直接影响着板形控制精度.随着板形控制手段的不断更新,对板形模式识别方法提出更高的要求.为克服传统板形模式识别方法抗干扰能力差、逼近阶难以确定的缺点,依据模糊分类原理,运用欧式距离的择近原则对板形模式进行分类,完成板形信号的模式识别.在此基础上,为进一步提高识别精度,将20世纪90年代发展起来的具有全局优化能力的粒子群理论应用于板形模式识别,对模式识别的结果进行优化,并将其与单纯形法优化结果进行对比.试验结果证明了粒子群优化算法的有效性,该算法能够提高识别精度,使优化后的结果能更精确地控制板形调控机构,以适应高精度板形控制要求.     

基于虚拟仪器的板形模式识别系统研究

介绍了气动板形检测辊的板形信号检测原理,详细阐述了普通多项式最小二乘法、正交多项式最小二乘法和基于欧氏距离的模糊模式识别法,利用虚拟仪器LabVIEW软件开发了基于上述三种方法的板形模式识别系统。通过气动板形仪在线测试了300型可逆冷轧机板形张力信号,并对张力信号进行了模式识别。实验表明：该板形模式识别系统具有良好的稳定性和有效性,良好的图形交互界面和实时测试性能为板形闭环控制提供了方便。     

Predicting settlement along railway due to excavation using empirical method and neural networks

More and more excavation projects are being performed near existing buildings and structures due to large-scale urban construction, in which the excavation unavoidably causes settlement and potential danger to the surrounding construction and buildings. For linear traffic facilities parallel to the excavation, the settlement profile parallel to the excavation, namely, the settlement along the traffic line, should also be considered. Moreover, the precise control of the differential settlement along the traffic lines also plays a very important role. Thus, it is necessary to establish a quick prediction model, which is able to consider both vertical and parallel settlement profiles, using the basic information on the excavation. Based on the large amount of field data, the characteristics of the settlement profiles are analyzed. A simplified empirical method is proposed; it is established based on the Rayleigh and Gauss distribution functions for predicting the ground settlement along railways induced by an excavation. Meanwhile, back-propagation neural networks are also used to predict the settlement behavior. A comparison between the predicted results and the monitoring data is given to verify the feasibility of the proposed method. A good agreement indicates that the proposed method can be employed to predict the settlement along railways due to an adjacent excavation.     

地下环境物流超深垃圾转运节点关键技术问题

超深地下垃圾转运站是城市地下环境物流系统的重要节点,其设计深度往往将超过50 m,由此带来了一系列复杂的岩土力学、工程力学和施工力学问题。本文阐述了转运站的概念设计和工作流程,综述了在上海地区典型软土地层进行转运站超深竖井设计施工的过程中可能会遇到的竖井周围岩土环境建模技术、竖井薄壁结构安全设计技术、竖井端部接头构造技术以及敏感环境下的竖井施工技术等关键技术问题。上述关键技术问题的分析对超深地下垃圾转运站的未来研究具有指导意义,是对现代城市大深度地下空间开发的一次有益探索。     

Controlling subsidence caused by de-watering in a deep foundation pit

In China, more and more underground structures are being built close to buildings of architectural merit. When installing deep foundations, three ways of controlling seepage are suggested. In Mode III, an installed curtain extends partly into the confined aquifer so that the hydraulic connection between the excavated section and the water in the host material is partly isolated. The combined effects of pumping, curtain efficiency and recharge are discussed. Based on the engineering geological conditions of the deep foundation pit of the Yishan Road Station of Metro Line 9, Shanghai, China, in situ pumping and recharge tests were carried out. The combined effects are similar to the results obtained using a three-dimensional finite difference method (FDM) numerical simulation.     

黄酒酵母的改良及对产物中尿素和氨基甲酸乙酯含量的影响

氨基甲酸乙酯（EC)是一种潜在致癌物,在黄酒发酵过程中尿素是它的前体物质。该研究通过紫外诱变和基因过表达筛选获得改良黄酒酵母菌种,并对黄酒产品的理化指标进行检测可知,与出发菌株相比,改造菌株的发酵性能和黄酒的出酒率、酒精度、总糖、总酸、氨基酸态氮和β-苯乙醇没有明显的差异,而诱变菌株JF501-A62发酵产物尿素含量降低了67%,EC含量降低了59%;基因过表达菌株JF501-B5发酵产物尿素含量降低了88%,EC含量降低了63%。两者均有很好的发酵性能,并取得了较好地降低产品中尿素含量、进而降低氨基甲酸乙酯含量的效果。与紫外诱变相比,基因过表达的改良方法获得了尿素含量更低的菌株,并贮存6个月之后产品中的EC含量更低。     

藜蒿中绿原酸的密闭微波辅助萃取研究

应用具有温度控制附件的密闭微波萃取装置,通过正交试验,对藜蒿茎中绿原酸进行微波萃取研究。讨论了提取溶剂浓度和用量、微波提取时间和微波功率对微波萃取的影响。实验表明,以体积分数50%的乙醇水溶液为提取剂,原料:提取剂(g∶mL)=1∶20,在微波功率400 W和温度70℃下萃取12 min,绿原酸的提取率最佳。此外,将微波萃取与乙醇回流提取进行了比较。     

Polynosic纤维衬衫面料的开发

为了顺利生产Polynosic纤维特细号衬衫面料,以精梳棉涤混纺纱线作经纱,新型原料Polynosic纤维纯纺纱作纬纱,交织生产了特细号衬衫面料.介绍了Polynosic纤维的性能特征、产品对原纱的质量要求,认为整经工序应注意张力、排列、卷绕三均匀,浆纱工序采用小张力、高浓度、低粘度、中压力的工艺路线,织造工序合理调整上机工艺参数,可有效消除断纬、双纬、跳纱等织疵,使织造效率达92%,下机一等品率达88%.     

Characterization of tilapia (Oreochromis niloticus) skin gelatin extracted with alkaline and different acid pretreatments

Tilapia production is growing worldwide and to better utilize wastes from the processing industry, one important application is production of high quality fish gelatin to meet the needs of markets that are not amenable to beef or porcine gelatin. The extraction process from tilapia skin gelatin was optimized through the use of a combination of alkali (0.3 M NaOH) with different types and concentrations of acids before thermal hydrolysis. The effects of acid pretreatments on the protein yields and the physicochemical properties of tilapia gelatin were investigated. Acid concentrations (0.01–0.20 M) influenced gelatin protein recovery: 10.52%–22.40% for citric acid, 1.92%–21.55% for acetic acid, and 4.47%–24.35% for HCl. It was possible to increase gelatin yield for each of the tested acids by adjusting the acid concentration. Gelatin viscosity and the molecular weight distribution of gelatin proteins were related to the acid concentration used. Gelatin prepared using too low a concentration (e.g. 0.01 M acetic acid or HCl) or too high a concentration (e.g. >0.05 M HCl or citric acid) yielded an extract with a smaller ratio of large molecule components, such as β-chains, and exhibited lower viscosity. The film forming properties of gelatins extracted from three acid-optimized pretreatments showed no significant difference in transparency, tensile strength and elongation at break; though the gelatin film made from 0.03 M citric acid pretreated gelatin had somewhat better water barrier property than those made with HCl or acetic acid.     

Controlled Synthesis on Ag Nanowires for Conductive Transparent Electrodes

One-dimensional silver nanomaterials, nanorods, and nanowires (NWs) were achieved by a solution-phase method. The geometry of the silver nanostructures was successfully tuned by adding polyvinylpyrrolidone (PVP) of different molecular weights. A possible mechanism, involving the suppression effect from PVP on the growth rates at different crystal facets, is used to explain the PVP-dependent morphology of the Ag nanowires achieved in this experiment. To evaluate its potential application in transparent electrodes, we also investigated the electrical conductance and optical transmittance after NWs were transferred to transparent polyethylene terephthalate substrates. Our findings indicated a possible and simple approach to control the morphology and then the functional properties of nanostructured silvers.