磁场、温度对Bi—2223／Ag多芯带Jc的影响

介绍了一套液氮温区Jc（B,T）测量系统,该系统用增大液氮的饱和蒸气压来达到提高液氮温度的目的。用该系统研究了磁场的温度（测量范围分别为0.1T～ 0.8T和77K～90K)对Bi-2223/Ag多芯带材（19芯和37芯）临界电流的影响。     

无纬绑扎带在复合外套MOA中的应用

芯体成型工艺是决定复合外套 MOA的技术性能和成本的关键。笔者分析了各种芯体成型工艺的利弊 ,介绍了无纬带的性能及选用方法 ,并简要介绍了无纬带芯体成型工艺及常见问题的解决措施     

红外光谱分析在AlN流延浆料分散性能测试中的应用

采用沉降法测定蓖麻油在ＡｌＮ流延浆料中的分散效果．结果表明：分散剂添加量为粉体重量的１～１．５％时,对本文所述的ＡｌＮ粉料而言分散效果最好．应用傅立叶红外光谱分析法,研究蓖麻油在ＡｌＮ流延浆料中的分散机理．结果表明：蓖麻油分子上的羰基与ＡｌＮ中的氮原子形成ｎ－π共轭结构,能有效地吸附在ＡｌＮ陶瓷颗粒表面,使蓖麻油长链分子分散在ＡｌＮ颗粒周围,产生良好的空间位阻分散．获得了均匀的,流动性好的ＡｌＮ流延浆料．     

Effect of Acrylic-Styrene Copolymer Chemical Structure on the Properties of Ceramic Tapes Obtained by Tape Casting

The results of studies on the effect of the chemical structure of acrylic-styrene copolymers on the properties of ceramic tapes from Al₂O₃ obtained by the tape-casting method are presented. The properties of the emulsions that serve as ceramic binders have been modified by insertion of selected amphiphilic macromonomers and acrylic acid into the polymer molecules. These amphiphilic macromonomers, because of the proper ratio of the hydrophilic to hydrophobic fragments, serve as internal plasticizers and modifiers of the adhesion of such binders to the ceramic powder particles. The presence of carboxylic groups as polymer pendant groups in an optimal amount has an additional effect on the ceramic tape density, uniformity, and mechanical properties, before and after the sintering process.     

利用I／O IMAGE SYSTEM进行磁带的拷贝

本文介绍了3种磁带拷贝的方法,便于仪器操作员根据野外实际情况灵活地进行磁带拷贝工作。     

FRP标线材料的制备及性能研究

近几年,新型的道路标线带成为发展趋势.本文采用模压成型工艺,以玻璃纤维布为增强材料、以丙烯酸酯改性不饱和聚酯树脂为基体制作FRP标线.性能分析表明,标线材料的耐水、耐碱性能非常优良,力学性能优异;采用环氧树脂胶黏剂粘结FRP在水介质中与基面的粘结强度优异;FRP标线具有良好的耐磨性,标线的使用寿命预计远远好于现有道路标线材料.     

面向复合材料自动铺放设备的输带速度与张力协同解耦控制

根据复合材料自动铺带成型的工艺参数要求，研究自动铺带机的输带速度与张力的协同解耦控制. 依据自主研发的铺带头建立预浸带输送系统的非线性时变双输入双输出模型，采用PI控制与对角矩阵解耦控制相结合的控制算法实现输带速度与张力的协同解耦控制. 在动力学仿真环境下进行输带速度与张力的跟踪实验，初步验证控制算法的可行性；在复合材料自动铺带机上进行的控制实验结果表明，提出的控制算法可以实现输带速度与张力的协同解耦控制，且具有较强的抗干扰能力，输带速度跟踪和张力跟踪的均方根误差(RMSE)分别为0.008 5 m/s和0.593 1 N·m，相比于PI控制分别降低了47.9%和36.2%. 实验结果充分验证了所提控制策略的有效性，该控制策略可用于复合材料铺放过程中的输带速度与张力的协同控制.     

Enhanced colorimetric detection of hydrogen using PdO-decorated ZnO covered with a metal-organic framework membrane

Safety concerns dictate the need for an affordable method of detecting the leakage of hydrogen. Simple colorimetric hydrogen sensors may provide a solution for achieving such detection. Herein, we report significant enhancements in eye-readable hydrogen detection via the formation of a metal-organic framework membrane on the surface of a hydrogen-responsive pigment. As a model system, PdO-decorated ZnO covered with a zeolitic imidazolate framework-8 (PdO/ZnO@ZIF-8) is synthesized and verified through material characterizations. When compared to a bare PdO/ZnO sensor, a colorimetric hydrogen sensor fabricated from PdO/ZnO@ZIF-8 yields a remarkably shortened response time, a moderate increase in detection sensitivity, and a significant enhancement in selectivity against potential interferents. These improvements are interpreted with the molecular sieving effect, electronic modulation of active centers, and accelerated sorption kinetics of hydrogen. The outstanding pigment is utilized to prepare a hydrogen detection tape that demonstrates a great potential in naked-eye detection of a hydrogen leak.     

Experimental study of exergetic performance of Al2O3 nanofluid in a double‐pipe heat exchanger fitted by a new modified twisted tape

The use of nanofluids and surface enhancers today are among the new technologies used to increase heat transfer. In this study, heat transfer phenomena in heat exchanger were investigated using Al₂O₃ nanoparticles and modified spiral band as flow turbulator. Results are verified with well‐known correlations. The results show that the tube with cross‐hollow twisted tape inserts has the best exergetic performance for different hollow widths of the tape. Clearance, which is defined as the width between the tube and twisted tape, also affects the heat transfer performance. The smaller the clearance, the better is the exergetic performance. The tube can achieve the best exergetic performance when the number of unilateral twisted tapes is four. The results showed that increasing nanofluid concentration improves exergetic performance.