基于混合优化策略的智能集装箱预翻箱系统*

讨论了一个智能集装箱预翻箱系统的设计与实现。在将集装箱预翻箱问题分解的基础上,采用混合优化策略来实现集装箱预翻箱方案。混合优化策略首先根据堆箱规则构造集装箱堆栈目标状态,然后运用改进广度优先算法搜索搬箱步骤。系统是运用分层设计思想来设计的,它是在生产调度领域应用人工智能理论和方法的有益尝试。     

金属化竹纤维的8mm微波干扰性能研究

为研制一种轻质毫米波干扰材料,试验以化学镀的方式对竹纤维进行表面金属化改性(镀覆的金属为铜和镍);并检测了金属化竹纤维的8mm波衰减性能.测试结果显示金属化竹纤维的8mm波衰减性能较好:20mg镀铜竹纤维可衰减17.5dB,30mg镀镍竹纤维可衰减24.2dB.化学镀工艺对金属化竹纤维的衰减性能有一定影响,在相同工艺下所制备试样的8mm波衰减分贝值随测试用量的增加而增加.试验结果表明金属化竹纤维可望成为一种新型毫米波干扰材料.     

竹炭的改性及对PP废塑料性能影响的研究

首先用硅烷偶联剂γ-氨丙基三乙氧基硅烷(KH550)处理竹炭(BC)得到K-BC,再通过熔融共混制备了一系列的K-BC/聚丙烯废洗衣机料(X-PP)复合材料,通过扫描电子显微镜(SEM)表征了BC的形貌,分析了K-BC含量对复合材料物理性能、尺寸稳定性、热变形温度(HDT)及维卡软化温度(VST)的影响。结果发现,BC内部拥有很多的孔隙,且这些孔隙都能被X-PP填充;KH550处理后的BC对X-PP的物理性能、尺寸稳定性、热变形及维卡软化温度的提升比未处理的BC好;随着K-BC的加入,复合材料的熔体质量流动速度、缺口冲击强度和断裂伸长率降低,K-BC添加量越大,降低的越多;复合材料的弯曲模量、HDT、VST和尺寸稳定性随着K-BC添加量的增大而上升,拉伸强度和弯曲强度随着K-BC添加量的增大,先增大后减少。     

Improving the Performance of Bamboo and Eucalyptus Wood fiber/Polypropylene Composites Using Pectinase Pre-treatments

The potential for using pectinase as a pre-treatment to improve the properties of bamboo or eucalyptus fibers for use in a woody fiber/polypropylene (PP) composite was compared with the addition of a silane coupling agent or NaOH pre-treatment. Pectinase pre-treatment reduced the amount of pectin in both fibers (p < 0.0001) and this reduction was associated with improved tensile strength, modulus of rupture and modulus of elasticity (p < 0.001) of bamboo, or eucalyptus fiber-based composites. Pre-treatment had no consistent effects on the thickness swell or water absorption. The addition of a coupling agent produced similar improvements in panel properties (p < 0.05), but also markedly reduced moisture absorption and thickness swell (p < 0.05). Sodium hydroxide pre-treatment had no consistent effects on panel properties, although it did appear to affect thickness swell. Short pectinase pre-treatment might be useful for enhancing the properties of woody tissue/PP composites while reducing but not completely eliminating the need for coupling agents.     

MODIFIED CLOSED-FORM NUMERICAL ALGORITHM FOR PERIODIC VIBRATION RESPONSE OF MECHANICAL TRANSMISSIONS

A closed-form numerical algorithm (CFNA) is analyzed in detail. CFNA is widely used in mechanical dynamics for periodic solution of second-order original differential equations (SODE) with periodic time-variant coefficients. The principle of the algorithm is to discretize the motion period into many short time intervals, so the coefficient matrices of the equation set are regarded as constant in a time interval. Defects are found in the original algorithm in treating the modal coordinates at the two end-nodes and important modifications to the defects is made for the algorithm. The modified algorithm is finally used to solve the dynamic problem of a three-ring planetary gear transmission.     

大型柔性轴承的设计及游隙的测量与计算

在某些对重量要求严格控制的场合,必须对各零、部件进行减重设计,作为转动副的轴承也不例外,经过减重设计的轴承称之为柔性轴承,文中提出了大型柔性轴承的几点设计要素及轴承游隙的测量和计算的方法。     

Durable,self-cleaning and superhydrophobic bamboo timber surfaces based on TiO2 films combined with fluoroalkylsilane

Decorative materials, including bamboo timber, have been proposed to exploit their superhydrophobic and self-cleaning properties, but a comprehensive appraisal of their environmental adaptability is still deficient. In this paper, a robust and durable superhydrophobic surface was formed on bamboo timber substrate through a process combining chemical solution deposition and chemical modification. The superhydrophobic surface resulted from micro-nanoscale binary-structured TiO₂ films and the assembly of low-surface-energy fluorinated components, which exhibited a water contact angle of 163±1° and a sliding angle of 3±1°. The surface maintained superhydrophobicity after mechanical abrasion against 1500 mesh SiC sandpaper for 800 mm at the applied pressure of 1.2 kPa, indicating good mechanical stability. Moreover, the superhydrophobic surface exhibited good chemical stability against both acidic and basic aqueous solutions (e.g., simulated acid rain). After exposure to atmosphere for more than 180 days, the obtained surface still maintained a contact angle of 155±2° and a sliding angle of 6±2°, revealing good long-term stability. In addition, the as-prepared superhydrophobic surface exhibited almost complete wet self-cleaning of dirt particles with water droplets. It is believed that the method presented in this study can provide a straightforward and effective route to fabricate a large-area, mechanically robust, anticorrosive and self-cleaning superhydrophobic surface on woody materials for a great number of potential applications.     

双涡轮液力变矩器相转换点判定与特性预测研究

针对某双涡轮液力变矩器内部复杂的黏性流动状况,建立了三维数值模型,进行了流场数值模拟计算,提出了双涡轮液力变矩器不同工况的转折点的判定,并计算了高转速工况第一涡轮空转转速。通过数值计算结果对双涡轮变矩器的原始特性进行了预测,并与试验结果进行了对比分析,结果表明:该计算方法可准确对双涡轮变矩器进行相转换点的判定以及进行双涡轮变矩器的特性预测。     

国防计量工作改革的探讨

阐述了国防计量与民用计量的差别，计量工作的原动力以及对国防计量工作改革的探讨。     

靶场发射初始段雷达精密跟踪技术

航天战略地靶发射初始段测量除了产生必要的跟踪监视信息以外，更重要的任务是获取安控信息源，文章从靶场的雷达环境出发，说明常规跟踪雷达不能实现对复杂背景下的载体（星箭，导弹等）跟踪，经分析研究，提出了ＭＴＴ（Ｍｏｖｉｎｇ－Ｔａｒｇｅｔ－Ｔｒａｃｋｉｎｇ）技术的概念，实验室计算机仿真和工程样机在靶场跟踪的数据分析，说明ＭＴＴ雷达是实现初始段精密跟踪测量的一种有效手段。