一种外场天线测试转台设计

为了满足天线在野外的测试需要,提出了一种外场天线测试转台的结构设计;该转台采用蜗轮蜗杆传动方式,可实现天线的俯仰和方位运动;文中对转台的组成进行了描述,并针对俯仰部件和方位部件的结构设计分别进行了详细说明,同时分析了转台的受力情况,对驱动力矩和惯量匹配进行了校核计算,从理论上分析了传动精度和测角精度;实际测试表明,该转台结构设计完全达到技术指标要求,能够满足天线外场测试的需要。     

Optical testing of star sensor (II): Alignment of star sensor from off-line pictures taken in orbital test

Alignment error of an image sensor relative to the optical axis of a star sensor head and alignment errors between four heads were calculated from pictures taken in an orbital experiment. When comparing the image sensor alignment parameters in the orbital test and a ground test, both values matched well. By determining the relative relationship of the four heads using four pictures taken at the same moment in orbit and uploading the parameters to the star sensor system in orbit, the estimated attitude error was improved from 0.29 to 0.17°, though the accuracy was limited by the ±0.2° determination accuracy of the satellite itself. We estimated the attitude determination accuracy from separation angles between boresights of the four heads, calculated from pattern matching between downloaded pictures and a star catalogue. The estimated accuracy, in terms of potential optical performance, was 0.60 arcmin at 3σ, which is sufficient to satisfy the specification of 1 arcmin.     

超声萃取-酶标仪-微量法测定污染土壤中的总石油烃

石油的开采、运输、泄漏及石油产品使用量的不断增加,导致了严重的土壤石油污染,改变了土壤的理化性质,引起土壤中的微生物大量死亡,影响植物的正常生长,并能通过皮肤、呼吸、饮食等方式进入人体,危害健康。因此,土壤石油污染的修复刻不容缓,但修复效果的评价离不开土壤中残留石油的提取和检测,建立快速高效的石油提取和分析测定方法是非常重要的。该研究讨论了检测波长、提取剂种类、提取剂用量以及超声萃取次数、萃取时间、超声萃取功率等影响污染土壤中总石油烃提取的参数和变量,最终建立了一种超声萃取-酶标仪-微量法提取检测污染土壤中总石油烃的方法。确定优化的提取和检测条件为：紫外检测波长为304 nm,用石油醚作提取剂,土液比为1∶4,超声萃取2次,每次萃取时间为20 min,超声萃取功率为100 W。该优化条件下,土壤石油添加回收率是88.4%～101.6%,相对标准偏差均小于4.7%,提取测定结果符合环境分析化学检测要求。利用酶标仪代替紫外分光光度计进行检测,能更方便快速的得出结果,且测定溶液用量少,可以更好地推广应用于微量石油污染环境样品的定量检测。此外,该方法用石油醚和乙醇作为提取和定容试剂,克服了采用二氯甲烷、四氯化碳等有机试剂提取而造成溶剂消耗量大、易产生二次污染、不利于环境友好发展等缺点,是一种快速、高效、绿色的提取和测定污染土壤中总石油烃的方法。     

WDP-500C型平面光栅单色仪应用于实验教学的技术问题

针对WDP-500C型平面光栅单色仪未设有千位数字,致使其报警时不能正确处理的问题,提出了根据滑块的传动距离加长挡光板或将光电报警开关向短波段移动8.0 nm的解决方案,消除了由于单色仪设计问题而产生的故障.     

Experimental investigation of the aquatic propulsion caused by localised flexural wave propagation in immersed wedges and plates

This paper describes the results of the experimental verification of the idea of wave-like aquatic propulsion of autonomous and man-inhabited vessels first published about 10 years ago by one of the present authors (V.V.K.). The idea is based on employing the unique type of localised flexural elastic waves propagating along edges of wedge-like structures immersed in water (wedge elastic waves). Such wedge-like structures supporting localised elastic waves can be attached like fish fins to a body of a small ship or a submarine and used for their propulsion. The proposed principle of employing localised flexural waves as a source of aquatic propulsion has been biologically inspired by the specific swimming mode used in nature by stingrays. To verify the idea experimentally, the first working prototype of a small catamaran using the above-mentioned wave-like propulsion via the attached rubber keel has been build and tested in Loughborough University. The tests have been carried out in two phases, in a water tank and then in open water. The test results have shown that the catamaran was propelled very efficiently and could achieve the speed of 36 cm/s, i.e., about one vehicle length per second, thus demonstrating that the idea of wave-like propulsion of small man-inhabited craft is viable. The reported proof of the viability of this idea may open new opportunities for marine craft propulsion, which can have far reaching implications.     

一种多光路光轴平行性检测系统

介绍一种用于检测多光路光电设备光轴平行性的测试系统,该系统采用准直平行光管提供无穷远目标,并融合了CCD图像采集处理和计算机技术,通过计算目标靶十字中心和激光光斑中心之间在CCD上的像素跨距,计算出红外、可见光以及激光三轴相互间的平行性误差,系统的计算误差小于5。     

正交试验法优选都梁凝胶贴剂的提取工艺

采用超声法优选都梁凝胶贴剂中白芷、川芎药对的最佳提取工艺.按照L9（34）正交试验设计,以欧前胡素、阿魏酸的转移率及干浸膏得率为综合评价指标,用高效液相色谱法进行含量测定.结果表明,都梁凝胶贴剂中白芷、川芎药对的最佳超声提取工艺为：8倍量的80％乙醇提取2次,每次超声40min;此时浸膏中欧前胡素的平均含量为0.1379％,阿魏酸的平均含量为0.1410％.本实验所建立的高效液相色谱法的准确度、精密度与重现性良好;提取工艺简便,合理.     

Combined ultrasonic and gamma-irradiation to prepare TiO2@PET-g-PAAc fabric composite for self-cleaning application

The grafting of polyacrylic acid (PAAc) onto the fabric of Poly(ethyleneterephthalate) (PET) was loaded with TiO₂ by a mixture sonication of TiO₂ dispersed in AAc dissolved in acetone solvent. Ultrasonic irradiation was utilized as a tool for a good dispersion of TiO₂ onto the PET fabric. The grafted PET fabrics with acrylic acid AAc monomer were successfully obtained using gamma-ray induced graft polymerization, the degree of grafting PET-g-PAAc fiber was 105%. The chemical compositions and crystal structure of grafted TiO₂@PET-g-PAAc fabrics were characterized by ATR-FTIR and XRD. It was found that loading of PET fiber with in TiO₂ particles showing the formation of anatase and rutile as performed by XRD. The thermal property of TiO₂@PET-g-PAAc was investigated by differential thermal analysis (DTA). The obtained result indicated the thermal property of the grafted TiO₂@PET-g-PAAc was increased. Image of scanning electron microscope (SEM) indicated the good adherent and good distribution of PAAc and TiO₂ with PET fabric. The self-cleaning property of TiO₂@PET-g-PAAc has been evaluated by using three kinds of dyes as models.     

Fabrication of bacterial cellulose thin films self-assembled from sonochemically prepared nanofibrils and its characterization

Bacterial cellulose (BC) film formation could be a critical issue in nanotechnology applications such as biomedical or smart materials products. In this research, purified pretreated BC was subjected to high intensity ultrasound (HIUS) and was investigated for the development of BC films. The morphological, structural and thermal properties of the obtained films were studied by using FE-SEM, AFM, FT-IR, XRD, TGA and DSC characterizations. Results showed that the most favorable purification treatment was the 0.01 M NaOH at 70 °C for 2 h under continuous stirring. The most suitable ultrasound operating conditions were found to be, 1 cm distance of ultrasonic probe from the bottom of the beaker, submerged in cold water bath cooling around 12 ± 2 °C. The power (25 W/cm²), time (30 min), BC concentration (0.1% w/w), amplitude (20 μm) and frequency (20 kHz) were maintained constant.