Silica surface modification using different aliphatic chain length silane coupling agents and their effects on silica agglomerate size and processability

Silica surface was treated with various aliphatic chain length silane coupling agents and compounded in EPDM using an internal mixer, and their agglomerate sizes, viscosity, and extrudate swell were investigated. The treated silica compounds showed smaller agglomerate size, lower viscosity, and lower swell reduction compared to untreated silica compound after equivalent mixing times. Short chain silane treated silica compound exhibited smallest agglomerate size. Silane acted as dispersing agents and processing aids in silica/EPDM compounds.     

Ghost rods adopting the role of withdrawn baffles in batch mixer designs

In batch mixers the stirring of a fluid is known to be particularly effective when the motion of the stirring rods form nontrivial braids. This motion is desirable as it generates (predictable) exponential stretching of material lines. Additionally, it has also been recognized that flow structures themselves (such as periodic islands) may adopt the role of proxy or “ghost” stirring rods. For a number of designs (which form nontrivial braids), we investigate the prevalence of ghost rods that effectively replace stationary stirring rods (baffles) as the latter are removed from the batch mixer. We show (for the case of Stokes flow) that designs with fewer baffles have comparable material stretch factors to corresponding designs with all baffles present.     

A low noise heterodyne receiver for astronomical observations operating around 0.63 mm wavelength

A heterodyne receiver is described in which an InSb hot electron bolometer is used as a mixer. The local oscillator power is obtained by doubling the frequency of a backward wave oscillator. The receiver operates between 460 and 500 GHz (0.65–0.6 mm). Noise temperatures amount typically to 1000 K.     

双螺旋轴搅拌机性能试验

传统的双卧轴搅拌机存在混凝土容易抱轴、搅拌低效区、物料运动不流畅等问题。为解决这些问题,提出了一种新型的强制式混凝土搅拌机——双螺旋轴搅拌机,并对双卧轴搅拌机与双螺旋轴搅拌机各自特点进行了分析。对比试验结果表明:螺旋轴搅拌机搅拌混凝土20 s时的抗压强度,比双卧轴搅拌机搅拌混凝土30 s时的抗压强度提高2.4%;在相同的搅拌条件下,双螺旋轴搅拌机搅拌混凝土时电机电流平均值比双卧轴搅拌机降低6.9%。     

Model Tests of Coolant Thermal Mixing in the HTR-10 Hot Gas Plenum

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摆动式混合机性能研究

三维摆动混合机（简称ＳＢＨ混合机）是一种新型高效的粉体混合设备。该机能适用于上百种不同物料（例如药品，陶瓷以及布丁粉等）的混合。因其采用了一种全新的运动学原理，即除了平移和转动这两种基本运动之外，又引入了可倒置的第三种运动，故具有极高效率。此种独特的可倒置翻滚运动特别有利于解决粉体加工工艺中，诸如混合效率与混合均度的问题。ＳＢＨ混合机适用于医药、染料、农药、化工、食品、石油、冶金矿山、烟火、炸药、复合肥料、陶瓷等工业部门以及农业种子和饲料部门的粉粒料混合。文中主要介绍该机的工作原理，结构性能及其它特点，为我国粉体加工工业的设备更新提供了一种新的途径。     

应用于OFDM之3．1～8．0GHz超宽带接收机前端芯片设计

使用TSMC0．18μmCMOS工艺实现3．1～8．0GHz超宽带接收机前端电路芯片设计,并利用ADS软件进行仿真、电路参数调整。电路架构包括：单端输入差动输出之超宽带低噪声放大器、Balun（Balance-unbalance）以及差动输入／输出的超宽带降频混频器,主要特点是在低噪声放大器输出端和混频器之间加入Balun,提升电路性能并减少芯片面积。芯片测试结果：在供给电压1.8V下,频宽为3．1～8.0GHz,S11〈-15。3dB,转换增益为24．6dB,功率消耗为37.98mW;包台接脚,芯片面积0．985（0.897×1.098）mm2。     

6.2～9.4GHz DC-OFDM超宽带接收机射频前端设计

设计了一个用于6.2~9.4 GHz超宽带中国国家标准的接收机射频前端.通过采用共栅输入、电容交叉耦合的低噪声放大器和正交跨导级合并的折叠型混频器,实现了对UWB小信号的放大和下变频.设计方案采用TSMC 0.13μm 1P8M RF CMOS工艺流片验证并进行测试.测试结果表明,输入匹配在6.2~9.4 GHz频段内...     

长叶片冷却风扇扭曲规律的气动优化设计

利用透平机械欧拉方程和经典的变分原理，推导出了内燃机冷却风扇沿径向气流参数优化设计的数学模型，建立了风扇叶片扭曲规律优化设计的数学方法．应用该方法对６１０２汽油机冷却风扇进行了优化设计，并将计算结果与等反击系数流型和自由涡流型的计算结果做了比较