基于示范城市创建的食品安全治理体系研究

食品安全示范城市创建是食品安全治理体系的重要载体。本文系统性回顾食品安全治理体系相关研究,从“党政同责”、政府监管、市场主体、社会共治等四个治理主体,构建生产规范、产业转型升级等27个评价指标的治理标准,利用层次分析法实证分析了浙江省食品安全示范城市创建情况。结果表明:采用暗查暗访、现场检查、体系评估、示范引领答辩等形式,按照一定的评价流程、评价标准的食品安全示范城市创建,是实现食品安全现代化目标的重要载体。食品安全治理体系包括“治理载体—治理主体—治理标准—治理目标”。食品安全治理成效与跟踪评价、群众满意度以及体系评估高度关联。     

YSZ/MoS2 self-lubricating coating fabricated by thermal spraying and hydrothermal reaction

Thermal sprayed ceramic coatings have extensively been used in components to protect them against friction and wear. However, the poor lubricating ability severely limits their application. Herein, yttria-stabilized zirconia (YSZ)/MoS₂ composite coatings were successfully fabricated on steel substrate with the combination of thermal spraying technology and hydrothermal reaction. Results show that the synthetic MoS₂ powders are composed of numbers of ultra-thin sheets (about 7 ~ 8?nm), and the sheet has obvious lamellar structure. After vacuum impregnation and hydrothermal reaction, numbers of MoS₂ powders, look like flowers, generate inside the plasma sprayed YSZ coating. Moreover, the growing point of the MoS₂ flower is the intrinsic micro-pores of YSZ coating. The friction and wear tests under high vacuum environment indicate that the composite coating has an extremely long lifetime (>?100,000 cycles) and possesses a low friction coefficient less than 0.1, which is lower by about 0.15 times than that of YSZ coating. Meanwhile, the composite shows an extremely low wear rate (2.30?×?10^?7 mm³ N^?1 m^?1) and causes slight wear damage to the counterpart. The excellent lubricant and wear-resistant ability are attributed to the formation of MoS₂ transfer films and the ultra-smooth of the worn surfaces of hybrid coatings.     

利用信息融合方法的三维特征提取

本文提出了一种基于信息融合的物体三维特征的提取方法，该方法利用两幅互相配准的三维测距图像和灰度图像，来提取多面体的三维特征。首先，通过分析灰度图像中的灰度变化及测距图像中的测距值变化，分别求取各自图像中物体的特征点及特征边；然后，利用两配准图像之间的对应关系，求得所有特征点、面与多边形在三维测距图像中的三维表示；接着，通过分析三维测距图像中所测得的各候选平面上特定点与边处的曲率及法向，验证候选平面     

VMS DCL命令的最简输入方法

本文给出了在VAX/VMS上用键定义设施和主谓模式实现的一种最简命令输入方法,它能极大地提高计算机系统的利用率和程序员的工作效率。文中给出了全部程序列表和一个应用实例。     

安棚深层系凝析气井射孔压井液技术研究

介绍了一种保护油气层的射孔压井液技术，该技术所用的配方具有低密度，低表面张力且具有较强的防膨能力等特点，在安棚深层系低孔低渗油田安3003等凝析气井作业中现场试验，解决了安棚深层系低压气井的水锁伤害等问题，对低孔低渗油气田作业入井流体的研究与应用具有较好的借鉴意义。     

运载火箭天基遥测技术

针对我国天基测控技术的发展趋势,提出了基于S频段终端通过中继卫星进行运载火箭天基遥测,以某运载火箭发射GTO轨道任务为例,分别对天线跟踪特性和链路增益进行了分析计算,介绍了运载火箭天基遥测系统的组成,分析表明,在满足天线跟踪角和链路指标的条件下,可实现天基遥测;这些分析结论可为工程应用提供参考。     

Fouling characteristics of 90° elbow in high salinity wastewater from coal chemical industry

Due to the high salt content of coal chemical wastewater, pipeline fouling often occurs during wastewater treatment. Fouling will cause the diameter of the pipe to shrink or even block, which is not conducive to the safe and stable operation of the wastewater treatment process. In this paper, the experimental device was designed by using FLUENT software and the fouling deposition mechanisms at different flow velocities and different positions in a 90 deg bend were studied. The experimental results show that when the flow velocity is between 0.2 m·s~(-1) and 0.3 m·s~(-1), the thickness of fouling layer was positively correlated with the flow velocity; when the flow velocity is equal to 0.4 m·s~(-1), the formation of fouling is the most serious; when the flow velocity is between 0.4 m·s~(-1) and 0.7 m·s~(-1), the thickness of fouling layer was negative correlation with the flow velocity; with the increase of inlet velocity, the time for sediment point to develop into sediment surface is shortened. The fouling layer is easy to fall off because of the large shear force on the wall surface of the inner bend of the 90° elbow, so the density of sediment at this position is high.     

考虑特征瞬变的导线微风振动在线监测及预警技术

针对现有导线振动监测以秒平均振幅和秒平均频率衡量导线微风振动程度带来的误差,提出了一种考虑振动特征瞬变的导线微风振动在线监测及预警技术。根据压电材料的正压电效应设计一种振动监测传感器,测量距悬垂线夹89 mm处的加速度时程曲线。以获得瞬时幅值和瞬时频率为目标,采用经验模态分解（empirical mode decomposition, EMD）结合相关性判断得到符合原始信号振动机制的特征模态函数（intrinsic mode function, IMF）,经希尔伯特变换（hilbert transform, HT）提取瞬时参数,并利用瞬时幅值和瞬时频率计算导线对应动弯应力下各单元损伤参数,通过数值方法证明其有效性。经振动台试验对比分析,导线在有效损伤频段0~60 Hz内,该方法得出的各项疲劳损伤参数与计算值的吻合度均在86.77%以上,且主要疲劳损伤参数最大试验误差为8.02%,平均试验误差为0.92%,说明该方法可以作为振动导线疲劳寿命预警的有效依据。     

SiCp／Al复合材料高应变率压缩变形及损伤机理

采用真空热压工艺制备了含SiC颗粒体积分数分别为5%,15%和25%的SiC颗粒增强铝基复合材料,利用Hopkinson高速压杆冲击实验系统对其从静态到动态(应变率为3.3×10-3s-1～5.2×103s-1)的压缩破坏响应进行了研究,结合其光学显微镜分析变形组织,分析了不同体积分数SiCp/Al复合材料高应变率压缩载荷下,材料的变形和微观损伤机理.结果表明,复合材料存在应变率敏感性,SiC含量的增加导致复合材料应变率敏感性的增加,以垂直于载荷方向的增强相颗粒的剪切开裂为主要破坏模式.     

定向凝固水平连铸多晶铜的动态本构方程

以带有同步组装技术的分离式Hopkinson压杆装置作为热模拟装置，采用基于MTS（Mechanical Threshold Stress）模型建立的FCC晶体结构的动态本构方程，确定了定向凝固水平连铸多晶铜动态本构方程参数，研究了其动态冲击特性，获得高温段（685K-1085K）的理论应力-应变曲线与实验曲线相当吻合，而在低温段（低于685K）的理论曲线与实验曲线出入较大。结果也表明定向凝固水平连铸多晶铜在485K和685K之间有一温度能使其回复能达到阀值。