活性炭改性研究新进展

从表面物理结构特性和表面化学性质两方面叙述了国内外在活性炭改性方面的研究进展.表面物理结构特性改性考察了增大比表面积和控制孔径分布,表面化学性质改性主要研究了氧化还原、负载金属离子以及微波改性,探讨了各种改性活性炭的优缺点和改性机理,并展望了其应用前景.     

盘磨机磨片间纸浆纤维剪切机理的研究

讨论了纸浆纤维在盘磨机打浆时所受到的剪切特性,并由此推导出平均剪切系数与磨片平均间隙、有用功及磨片几何尺寸之间的关系,这对研究中浓打浆过程的机理及提高打浆效率是十分重要的。     

Efficient hydrogen production from ammonia borane hydrolysis catalyzed by TiO2-supported RuCo catalysts

Hydrolysis of ammonia borane provides a reliable pathway for hydrogen production, while suitable catalysts are indispensable to make the hydrolysis reaction reach a considerable rate. In the present work, a series of TiO₂-supported RuCo catalysts have been fabricated by coprecipitation and subsequent reduction of Ru³⁺ and Co²⁺ on the surface of TiO₂ nanoparticles. Transmission electron microscopy and elemental mapping have verified the good distribution of metal species in the catalysts. The fabricated catalysts have shown excellent performance for catalyzing ammonia borane hydrolysis, especially in alkaline solutions with 0.5 M NaOH. For Ru₁Co₉/TiO₂ in which Ru/Co molar ratio is 1:9, the active energy of catalyzed ammonia borane hydrolysis is 33.25 kJ/mol, and a turnover frequency based on Ru as high as 1408 mol_H2/(mol_Ru·min) is obtained at 25 °C. Moreover, when different types of TiO₂ substrates are used, anatase TiO₂-supported catalysts show better catalytic activity than their counterparts with rutile TiO₂ as substrate or mixture of anatase and rutile TiO₂ as substrate.     

ACAS X监视特性分析及防欺骗技术探讨

总结分析了ACAS X的目标监视特性，指出ACAS X本身虽有较强的抗干扰能力，但随着扩展混合监视和ADS-B信息的深度应用，ACAS X可能会被一些技术手段欺骗。文章详细列举分析了这些欺骗手段，并指出可采用基于空域场景、基于几何相符与数据一致性、基于射频信号特征、基于欺骗信号时间和空间特征等验证技术对这些欺骗手段进行应对。文章选取基于几何相符与数据一致性的验证技术进行仿真，结果表明该技术可以得到更精确的飞机几何估计位置，能够发现一段航路中飞行器几何轨迹与飞机导航性能不符合的目标，进行虚假目标的滤除。     

圆坯连铸机的高效化改造与生产实践

通过开发和应用高拉速抛物线锥度结晶器，采用结晶器电磁搅拌和高精度板簧振动装置等工艺技术，对天津钢管公司Ф210-310mm圆坯连铸机二冷配水及拉矫机、冷床和计算机自动化系统进行了相应的改造，使连铸机拉速提高了30％，年产量由60万t提高到90万t，铸坯的综合合格率为99．66％。     

Ultrasound-assisted osmotic process on quality of microwave vacuum drying sweet potato

The effects of pretreatment before microwave vacuum drying (MVD) on texture, color, expansion, rehydration, drying rate, microstructure, sensory evaluation, and other properties of sweet potato were investigated in this study. The pretreatment consisted in five processing conditions, using blanching; osmotic dehydration at 35°Brix of sucrose (OD); ultrasound in distilled water (US); ultrasound in distilled water before osmotic dehydration (US?+?OD), and ultrasound-assisted osmotic dehydration (USOD). Pretreatments of sweet potato before MVD have shown success in reducing drying time with US treatment relatively more effective regarding drying time than other treatments. Compared with other treatments, US showed the highest rehydration ratio values. The osmotic group pretreatment exhibited a pronounced effect on water loss and solid gain, improved the color, aroma, and taste of dried sweet potato, whereas sucrose impregnation resulted in a hard texture observed with OD sample. USOD samples had a higher expansion ratio, lower hardness and color difference values, appeared less cell damaged, and recorded better overall quality than the other samples. There was a slight difference between USOD and US?+?OD samples. Combining osmotic dehydration with ultrasound as a pretreatment can significantly accelerate the heat transfer rate, reducing the dried time accordingly and increasing energy efficiency.     

STABILITY OF NANOCRYSTALLINE Ni-P RIBBONS

Stability of nanocrystalline Ni-P ribbons was investigated by DSC and internal frictiontechnique.The nanocrystalline Ni-P ribbons seem to be unstable within range of 518 to887 K owing to obvious exothermal phenomenon,decrement on internal friction valuesand grain coarsening.     

基于地标的轻量化无人机精准降落算法

轻量化无人机的机载计算机通常计算性能较弱,很难满足无人机实现精准降落的需要。针对这一问题,提出了一种基于地标的轻量化精准降落算法,通过识别对比颜色和指定形状实现快速实时地检测着陆标识,图像处理流程简单快速且准确,通过相对位置计算在二维层面得到无人机对于降落地标的相对位置和方向,引导无人机精准降落,算法执行过程不需要考虑相机焦距。实际测试结果表明,在一些特定如无人机自主充电的应用场景,该算法过程简单,稳定性和降落精度相较于传统方法较高。     

SRAM版图布局方向对产品失效率的影响

静态随机存储器(SRAM)是集成电路中重要的存储结构单元。由于其制备工艺复杂、关键尺寸较小、对设计规则的要求最为严格,因此SRAM的质量是影响芯片良率的关键因素。针对一款微控制单元(MCU)芯片的SRAM失效问题,进行逻辑地址分析确认失效位点,通过离子聚焦束(FIB)切片及扫描电子显微镜(SEM)分析造成失效的异常物理结构,结合平台同类产品的设计布局对比及生产过程中光刻工艺制程的特点,确认失效的具体原因。对可能造成失效的工艺步骤或参数设计实验验证方案,根据验证结果制定相应的改善措施,通过良率测试及SEM照片确认改善结果,优化工艺窗口。当SRAM中多晶硅线布局方向与测试单元中一致时,工艺窗口最大,良率稳定;因此在芯片设计规则中明确SRAM结构布局方向,对于保证产品的良率具有重要意义。     

纤维素纳米纤维接枝聚丙烯酸pH响应水凝胶的制备及性能

以硝酸铈铵为引发剂,将具有pH响应的聚丙烯酸(PAA)接枝到电纺纤维素(Cell)纳米纤维膜上,制备了pH响应纤维素接枝聚丙烯酸(Cell-g-PAA)纳米纤维水凝胶。研究了接枝单体丙烯酸(N)与纤维素(c)质量比对Cell-g-PAA形貌、接枝率和溶胀性的影响。结果表明:m(N)∶m(c)值从5增加到10,接枝率从11%急剧增加到28%,然后趋于平稳;而m(N)∶m(c)值从5增加到15,溶胀率从(15.2±1.6)g/g增加到(46.1±4.9)g/g,然后下降。同时,研究了pH值和离子强度对水凝胶溶胀率的影响,pH值从2.2增加到7.8时,水凝胶的溶胀率从(31.3±2.5)g/g增加到(42.7±3.2)g/g,pH值进一步增大,溶胀率降低;溶液中离子强度从0mol/L增加到0.15mol/L,水凝胶溶胀率从(36.2±2.6)g/g降低到(21.4±1.4)g/g。本研究为制备快速响应pH水凝胶提供了一种新方法。