面向机械产品专利规避的功能裁剪路径研究

专利日益成为知识产权战略下最重要的竞争性要素,掌握核心专利的企业通过设置专利壁垒阻碍后来者的竞争,因此如何针对专利技术进行创新设计,以突破专利壁垒将十分必要。为保障创新设计既为有效创新设计又不侵犯现有专利技术,考虑到功能裁剪与专利规避原则的契合性,首先基于专利制度约束与功能模型建立了专利权利范围;其次,基于不同专利规避原则对功能裁剪路径进行了研究;最后,基于专利规避前端设计准则,提出了完整的创新设计流程,并通过管道机器人实例验证了方法的有效性。     

电迁移对低银无铅微尺度焊点力学行为的影响

研究了电迁移条件下不同电流密度(0.63~1.0×104 A/cm2)和通电时间(0~48 h)对低银无铅Sn-Ag-Cu微尺度焊点的拉伸力学行为的影响. 结果表明,电迁移导致了低银无铅微尺度焊点的抗拉强度显著降低,并且随着电流密度的增加或通电时间的延长,焊点的抗拉强度均呈下降趋势;同时电迁移还导致焊点的拉伸断裂模式发生明显变化,在经历高电流密度或长时间通电的电迁移后,焊点在服役条件下会发生由韧性断裂向脆性断裂的转变. 此外含银量高的微尺度焊点的抗电迁移性能更强.     

Processing and mechanical properties of short fibers/Si3N4p reinforced BaO·Al2O3·2SiO2 ceramic matrix composites

Dense short silicon carbide (SiC_sf) and carbon fibers (C_sf) reinforced BaAl₂Si₂O₈ (BAS) glass-ceramic composites with silicon nitride were fabricated by hot-pressing technique. The phase characterization, microstructure, mechanical properties and fracture behavior of the composites were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and three-point bending tests. The results showed that short silicon carbide and carbon fibers disperse homogeneously in BAS matrix, and had good chemical compatibility with the glass-ceramic matrix. The addition of Si₃N₄ could successfully eliminate the microcracks in the BAS matrix induced by the thermal mismatch between the fiber and matrix. Both the added short fibers could effectively reinforce the BAS glass-ceramic by the associated toughening mechanisms such as crack deflection, fiber bridging and pullout effects.     

C-band fundamental/first-order mode converter based on multimode interference coupler on InP substrate

The design, fabrication and characterization of a fundamental/first-order mode converter based on multimode interference coupler on InP substrate were reported. Detailed optimization of the device parameters were investigated using 3D beam propagation method. In the experiments, the fabricated mode converter realized mode conversion from the fundamental mode to the first-order mode in the wavelength range of 1530-1565 nm with excess loss less than 3 dB. Moreover, LP₀₁ and LP₁₁ fiber modes were successfully excited from a few-mode fiber by using the device. This InP-based mode converter can be a possible candidate for integrated transceivers for future mode-division multiplexing system.     

Enhanced photoresponse of TiO2/MoS2 heterostructure phototransistors by the coupling of interface charge transfer and photogating

Two-dimensional (2D) MoS₂ with appealing physical properties is a promising candidate for next-generation electronic and optoelectronic devices, where the ultrathin MoS₂ is usually laid on or gated by a dielectric oxide layer. The oxide/MoS₂ interfaces widely existing in these devices have significant impacts on the carrier transport of the MoS₂ channel by diverse interface interactions. Artificial design of the oxide/MoS₂ interfaces would provide an effective way to break through the performance limit of the 2D devices but has yet been well explored. Here, we report a high-performance MoS₂-based phototransistor with an enhanced photoresponse by interfacing few-layer MoS₂ with an ultrathin TiO₂ layer. The TiO₂ is deposited on MoS₂ through the oxidation of an e-beam-evaporated ultrathin Ti layer. Upon a visible-light illumination, the fabricated TiO₂/MoS₂ phototransistor exhibits a responsivity of up to 2,199 A/W at a gate voltage of 60 V and a detectivity of up to 1.67 × 10¹³ Jones at a zero-gate voltage under a power density of 23.2 µW/mm². These values are 4.0 and 4.2 times those of the pure MoS₂ phototransistor. The significantly enhanced photoresponse of TiO₂/MoS₂ device can be attributed to both interface charge transfer and photogating effects. Our results not only provide valuable insights into the interactions at TiO₂/MoS₂ interface, but also may inspire new approach to develop other novel optoelectronic devices based on 2D layered materials.

     

α-sialon陶瓷材料的微结构控制及其力学性能优化

从影响α-sialon材料自韧化的关键因素出发,研究了Y,Yb,Nd等不同稀土类添加物、烧结工艺和后续热处理对α-sialon显微组织与力学性能的影响.结果表明:控制其反应动力学是获得自韧化α-sialon的关键.烧结工艺及后续热处理对α-sialon棒晶生长的促进作用依赖于其成分及掺杂的稀土氧化物类型.Y-α-sialon在1300～1700 ℃长时间低温退火,未发生α相向β-sialon相转变,但1500 ℃长时间退火将导致α-sialon的晶粒形貌由棒状向等轴状转变,引起材料的脆化.     

光无源器件温度冲击过程中光功率的实时监测

介绍了光无源器件温度冲击模拟试验中的状态实时监测的一种方法,给出了高低温冲击引起的附加损耗计算公式,并对1×2、2×2两种类型的耦合器进行了实验,分别给出了它们各两路输出光功率变化试验曲线,结果表明在温差140℃条件下,温度冲击对1×2、2×2耦合器造成的光功率变化幅度最大值分别小于0.5dB、2.0dB.     

基于光散射快速检测法的渭南市道路积尘研究

为掌握渭南市道路积尘分布特征及影响因素, 获取道路积尘本地化参数和道路扬尘的管控依据, 基于光散射 法利用道路积尘负荷车载式快速监测系统对渭南市城市道路积尘负荷进行了测定, 分析了不同类型道路的积尘负荷 特征, 并研究了车流量、车重及道路抑尘方式等与积尘负荷的关系。研究结果表明, 渭南市道路积尘负荷平均值为 1.13 g·m−2, 不同类型道路积尘负荷大小呈支路 (1.79 g·m−2) > 次干道 (1.22 g·m−2) > 省道 (1.08 g·m−2) > 主干道 (0.94 g·m−2) > 国道 (0.71 g·m−2) 的特征; 车流量和车速变化与道路积尘负荷值均呈负相关, 即车流量和车速越大, 积尘负荷 值越小; 此外, 洒水能有效降低道路积尘负荷值, 但保持时间较短, 因此建议改变重洒水弱清扫的作业模式, 重点关注 清扫除尘。     

Microstructure and mechanical properties of TaC ceramics with 1–7.5 mol% Si as sintering aid

Metallic Si as sintering aid was effective in densifying tantalum carbide ceramic (TaC) by spark plasma sintering (SPS) at 1700°C. Full density was reached at 5.0 mol% Si addition (equivalent to 1.088% Si in weight) and above. Enhanced densification of TaC ceramic with Si was associated with decrease in oxygen content from ~0.24 wt% in TaC powder to ~0.03 wt% in consolidated specimen. Rest of the oxygen species was collected at multigrain conjunctions to form SiO₂‐based liquid at high temperatures. Upon cooling, Ta, Si, O, and C dissolving in the liquid precipitated minor phases of TaSi_x and SiC of low concentrations. Microstructure of TaC ceramics was refined by the Si addition, with average grain size decreasing from 11±8 μm at 1.0 mol% Si to 3±2 μm at 7.5 mol% Si addition. Ta solute in SiC and Si solute in TaC were evidenced. TaC ceramic containing 7.5 mol% Si had a relatively good flexural strength and fracture toughness of 646±51 MPa and 5.0 MPa·m^1/2, respectively.     

基于电压钳位原理的多端口限流式直流断路器

随着直流电网技术的广泛运用,直流断路器作为关键保护设备已成为相关领域研究重点.提出一种基于电压钳位原理的多端口限流式直流断路器,具有通态损耗低、经济性良好、重合闸速度快等优点.首先,提出新型断路器的拓扑结构及动作策略,通过电压钳位原理切除故障,而后利用LC振荡关断支路晶闸管;其次,分别对母线和线路故障进行解析推导,进而针对其关断过程设计参数;最后,利用PSCAD/EMTDC中的三端直流电网模型验证其有效性与适用性,并分别对两种故障仿真加以分析,通过故障电流、系统电压及支路电压对比分析等验证该断路器可代替多个常规断路器,减少了主断路器需求.