Tooth flank modification theory of dual-torus double-enveloping hourglass worm drives

In this paper, the theory of tooth flank modification is enriched and developed for a double-enveloping toroidal worm drive. The goal and significance of the modification are expounded from the point of view of changing the tooth flank configuration for the worm gear pair. It is pointed out that the constant center distance modification, the constant transmission ratio modification, and the combination of the previous two are the convenient and reasonable modification strategies. All the corrected hourglass worm pairs, attained by employing the preceding modification methodology, can be divided into two fundamental types: the type I worm pair and the type II worm pair, from the perspective of the meshing behavior. The division criterion of the worm drive type is moreover provided on the basis of the value range of the modification parameters in this study. The meshing characteristics of the two types of the modified globoidal worm drive are summarized in detail. The results indicate that the type II worm gearing with slight modification should be the preferred style for the double-enveloping toroidal worm drive.     

新型环氧树脂泡沫塑料制备及其性能研究

采用两步法制备环氧(EP)树脂泡沫塑料,并对其结构和性能进行了表征。结果表明,EP固化完全,观察不到827cm-1处环氧基的特征峰。所得的EP泡沫塑料为闭孔结构,泡孔均匀,密度最低可达0.14g/cm3,玻璃化转变温度为107℃,起始分解温度为352.5℃。     

Room temperature ferromagnetism of Ni, (Ni, Li), (Ni, N)-doped ZnO thin films

Ni-doped ZnO thin films (Ni concentration up to 10 mol%) were generated on Si (100) substrates by a sol-gel technique. The films showed wurtzite structure and no other phase was found. The chemical state of Ni was found to be bivalent by X-ray photoelectron spectroscopy. The results of magnetic measurements at room temperature indicated that the films were ferromagnetic, and magnetic moment decreased with rise of Ni concentration. The magnetization of Ni (10 mol%)-doped ZnO film annealed in nitrogen was low...     

Co-channel Interference Energy Harvesting for Decode-and-Forward Relaying

In this paper, co-channel interferences are exploited for energy harvesting in a Cooperative Network (CICN) in which a power constrained relay uses a power splitting architecture (CICN-PS) and a time switching architecture (CICN-TS) to harvest energy from the radio-frequency signals received from a source node and co-channel interferences. In the proposed CICN-PS and CICN-TS protocols, the relay applies decode-and-forward technology to decode the information of the source node, and then forwards the recoded information to a destination with the overall harvested energies. The system performance of the proposed protocols is discussed and evaluated using the exact throughput analyses and is then checked using Monte Carlo simulations over Rayleigh fading channels. The optimal power splitting ratio and energy harvesting time are derived by the Golden Section Search method, and throughput performance evaluations are performed. Our numerical and simulation results show distributions as follows. Firstly, the CICN-PS protocol outperforms the CICN-TS protocol. Secondly, the proposed protocols strictly depend on the location, amount and power of the co-channel interferences. Thirdly, when signal-to-noise ratio increases, the proposed CICN-PS protocol achieves the perfect throughputs where the cooperative relay applies the ideal receiver and co-channel interferences do not affect the destination. Finally, the numerical analyses agree well with the simulation results.     

掺铒光纤激光器

简述了掺铒光纤激光器(EDFL)的原理、结构和发展,着重介绍了自启动、被动锁模的掺铒光纤孤子激光器的结构和特性。     

AND:Rubrene发光层的有机电致白光器件

利用9,10-bis(2-naphthyl) anthracene(AND)掺杂rubrene作为器件单一发光层,研制成功单层白光器件。器件在电流密度为140mA/cm2时,电流效率达到5.93cd/A;当电压为21V时,该器件达到最高亮度9300cd/m2。器件发光色坐标为(0.32,0.40),且随着电压的变化发光色度始终处于白光区。这种器件的白色发射是来源于AND(蓝色发射)和rubrene(橙色发散)的混合发射。与此同时,AND和rubrene二者之间会发生Frster能量传递。     

保密传真通信系统的仿真实现

实际的保密传真通信系统是一个功能结构复杂的系统。在建立新系统前,通常需要对系统进行建模和仿真以消除系统中潜在的瓶颈,提高系统成功的概率。文中在分析了保密传真通信系统的工作原理之后,对保密传真通信系统的信源编码模块、加解密模块和调制解调模块进行了Matlab仿真实现,仿真结果达到了预期目标。     

城域综合承载传送网的网络架构

随着业务和电信网络的IP化和宽带化,在城域（本地）网实现各种业务的综合承载传送已成为可能。根据各种承载业务的特点和网络现状,提出城域综合承载传送网络的目标网络架构、业务承载及网络演示方式。     

Dual-band stacked folded shorted patch antenna

A novel stacked folded shorted patch antenna for dual-band operation is presented. It has impedance bandwidths (SWR<2) of 22.9 and 20.3% in the lower and the upper bands, respectively. It is 0.0461lambda_L in height and 0.27lambda_L in length, where lambda_L is the free space wavelength at the centre frequency of the lower band. Therefore, it is very suitable for today's multi-band wireless communication systems.     

A Biologically Muscle-Inspired Polyurethane with Super-Tough,Thermal Reparable and Self-Healing Capabilities for Stretchable Electronics

Polymeric elastomers play an increasingly important role in the development of stretchable electronics. A highly demanded elastic matrix is preferred to own not only excellent mechanical properties, but also additional features like high toughness and fast self-healing. Here, a polyurethane (DA-PU) is synthesized with donor and acceptor groups alternately distributed along the main chain to achieve both intra-chain and inter-chain donor-acceptor self-assembly, which endow the polyurethane with toughness, self-healing, and, more interestingly, thermal repair, like human muscle. In detail, DA-PU exhibits an amazing mechanical performance with elongation at break of 1900% and toughness of 175.9 MJ m⁻³. Moreover, it shows remarkable anti-fatigue and anti-stress relaxation properties as manifested by cyclic tensile and stress relaxation tests, respectively. Even in case of large strain deformation or long-time stretch, it can almost completely restore to original length by thermal repair at 60 °C in 60 s. The self-healing speed of DA-PU is gradually enhanced with the increasing temperature, and can be 1.0–6.15 µm min⁻¹ from 60 to 80 °C. At last, a stretchable and self-healable capacitive sensor is constructed and evaluated to prove that DA-PU matrix can ensure the stability of electronics even after critical deformation and cut off.