Performance analysis of bit error rate of data link system under pulse LFM interference in time-varying rayleigh channel

Wireless Networks - In such mobile platforms as ships and aircraft, the detection and reconnaissance devices are near to the communication facilities. When working at the same time, they will...     

Research on children's personalized sports in the environment of smart wearable devices

The audit point is to understand and use to perform the upgrade wearable innovation injuries in sports. Understanding the game's biomechanics is that damage response and performance upgrades are essential, and usually, investigation uses optical motion capture. In any case, this approach may be limited by the amount of limit catch climatic factors and the overwhelmed wearable research center of innovation. Ordered to make queries are used to study in seven information centers and sports car wearable innovation factors. This article was banned because they do not measure the program members on the sensor zero and the motor or motor factors or the application of an innovative set. Thirty-three incorporated into the collection of the full text of the survey carried out to identify members' dynamic development through observation and a slice of wearable progress in the game. Inertial sensors, the sensor and the flexible, attractive and precise speed field sensors are used in the game with more than 15 measured motion gadgets. The use of wearable innovation, the potential of these innovative practices, and the impact of competitors' training methods are still in the exploratory stage.     

Reconstructed Water Oxidation Electrocatalysts: The Impact of Surface Dynamics on Intrinsic Activities

Electroreduction of small molecules such as H₂O, CO₂, and N₂ for producing clean fuels or valuable chemicals provides a sustainable approach to meet the increasing global energy demands and to alleviate the concern on climate change resulting from fossil fuel consumption. On the path to implement this purpose, however, several scientific hurdles remain, one of which is the low energy efficiency due to the sluggish kinetics of the paired oxygen evolution reaction (OER). In response, it is highly desirable to synthesize high-performance and cost-effective OER electrocatalysts. Recent advances have witnessed surface reconstruction engineering as a salient tool to significantly improve the catalytic performance of OER electrocatalysts. In this review, recent progress on the reconstructed OER electrocatalysts and future opportunities are discussed. A brief introduction of the fundamentals of OER and the experimental approaches for generating and characterizing the reconstructed active sites in OER nanocatalysts are given first, followed by an expanded discussion of recent advances on the reconstructed OER electrocatalysts with improved activities, with a particular emphasis on understanding the correlation between surface dynamics and activities. Finally, a prospect for clean future energy communities harnessing surface reconstruction-promoted electrochemical water oxidation will be provided.     

Synchronized motion and compliant control for dual control moment gyroscopes by realizing the impedance transformation matrix

In this paper, dual control moment gyroscopic actuators (CMG) were formed in a scissored-pair configuration to maximize the induced torque in the desired direction. A robust synchronizing motion control method was proposed to regulate the directional gyroscopic torque. In order for the two CMGs to form a scissored-pair structure having opposite angular momentum vectors, the synchronization of two CMGs was done without losing the control capability due to axial drift. A transformation matrix was designed for the robust synchronization control performance by realizing the empirically discovered impedance models of CMGs. Three different control modes were realized by selecting the components of the impedance transformation matrix (ITM): a robustly independent control mode, a synchronized motion control mode, and a mixed motion control mode. Each CMG played the role of either a master or a slave and copied the motion from another to follow it under the synchronization mode. The experimental results show that two CMGs can generate a robust and directional torque under the mixed control mode of both robust and synchronization control.     

Soluble polyimide as liquid crystal perpendicular alignment layer

Journal of Materials Science - Three polyimides (PIs) were prepared from a diamine containing biphenyl ester group as a side chain and a corresponding dianhydride chosen from...     

某铁矿强磁尾矿反浮选回收试验研究

针对我国西部某铁矿强磁选尾矿进行了反浮选回收铁资源的试验研究, 探讨了pH值、抑制剂可溶性淀粉用量、阳离子捕收剂十二胺用量对浮选指标的影响。结果表明, 在矿浆pH=10、可溶性淀粉用量2 400 g/t、十二胺用量400 g/t条件下进行一粗一精(精选药剂用量减半)闭路反浮选, 可获得铁品位43.88%、回收率50.93%的铁精矿产品。     

Stability,reactivity and decomposition kinetics of surface passivated α-AlH3 crystals

As a novel high energy fuel, aluminum hydride (AlH₃) has great potential in the field of solid propellants because of its high hydrogen capacity, which can significantly improve the specific impulse of solid propellants. In order to improve the stability of α-AlH₃, hydrochloric acid has been used to stabilize AlH₃ and the stabilization mechanism has been investigated. Various characterization techniques including scanning electron microscopy, X-ray electron spectrometer, X-ray diffraction, thermal analysis, and vacuum stability test have been employed to investigate the morphology, crystal structure, thermal stability, and decomposition kinetics of raw and passivated α-AlH₃. The results showed that the honeycomb-like structures could be formed on the surface of α-AlH₃ after passivation. First of all, the initial decomposition temperatures of the passivated samples were slightly increased. In particular, for the optimized sample with 105 min passivation time (AlH₃-105min), the initial decomposition temperature (173.4 °C) is increased by 5.6 °C. Moreover, the total decomposition time (1652 min) is improved by about 50% than that of the raw sample (1098 min). Besides, the decomposition activation energies (E_a) of passivated samples are much higher than that of the raw sample (84.8 kJ mol^?1), in which the optimized sample (AlH₃-105min) reaches 107.1 kJ. mol^?1. The decomposition kinetics model may change from 3-D nucleation and nucleus growth model to 2-D nucleation and nucleus growth model. It demonstrates the passivated samples have a lower decomposition rate and higher thermal stability. The stabilization mechanism is as follows: removing the impurities on the surface and accelerating the hydrolysis reaction of AlH₃ to generate complete and dense oxide layers.     

基于章水泉竹艺非物质文化遗产的APP设计与研究

目的 针对章水泉竹艺非物质文化遗产在目前所遭遇的传承困境，利用数字媒体技术与互联网平台，打造推动其产品创新与文化传承的APP，助力其文化与产品的传播与推广，进而为湖北地区的非遗文化发展提供参考。方法 从章水泉竹器的本源出发，对其主要产品门类、工艺特点与艺术形式进行整理与分类，分析制约其传承与发展的主要原因，进而提出设计策略，并通过数字化传承、合作创新、成果推广3个策略模块针对性地进行APP设计。结论 章水泉竹艺APP设计通过利用数字媒体技术与互联网平台优势，将其历史与工艺资料进行数字化保存与展示，实现了文化保护功能；将其传统技艺与新锐设计思维通过线上平台进行融合与创新，实现了设计创新功能；将其制作流程与文化精髓通过直播与精准推送展现于公众视野，实现了产品推广功能。最终，为章水泉竹艺的传承与推广提供了新的路径。