新型免抬式电动刀架的研究

本文介绍了一种ＣＮＣ机床新型免抬式电动刀架的机械结构及控制电路。该电动刀架采用梯形螺柱螺套副升降机构，可使刀架转位分度时无需抬起上刀体。刀架转位分度采用机－ 电结合的方法，即先在控制电路中使用霍尔元件进行粗定位，再在机械上采用三齿盘实现精定位。     

旋转带肋回转通道换热实验研究

为深入掌握高压涡轮叶片带肋回转通道在旋转状态下的换热分布,建立了旋转内通道实验系统,利用瞬态液晶测量方法研究了动叶回转内通道模型的换热机理,比较了三维数值模拟和实验的换热结果。通道入口雷诺数为5000~17000,旋转数为0~0.09,旋转半径与水力直径之比为46.4。结果表明:不同雷诺数下回转内通道的局部换热系数分布相似,局部、平均换热系数均随雷诺数增加而增大;沿程展向平均换热系数呈多波峰状分布,肋的扰动强化换热沿流向逐渐减弱;径向出流通道的努赛尔数随旋转数增加明显增大,径向入流通道的努赛尔数随旋转数的增加略有减小;哥氏力使转弯下游通道的局部换热系数改变,肋间的高换热区域由前肋的背风面附近向两肋之间偏移。     

Functional models for space power electronic circuits

Presented here is a new approach to model power electronic components so that system level issues of large space power systems can be studied. To demonstrate this approach, the models for two major power electronic components in the space station power system are described. The new models are useful not only in system level studies but also in the design/analysis of particular components     

Parametric Modeling of Circuit Model for AC Glow Discharge in Air

In the parametric modeling of the circuit model for glow discharge in air,a new method for the design of glow discharge circuit model is presented.The new circuit model is an important reference for the design of plasma power supply,the simulation of glow discharge plasma actuator and the simulation of glow discharge plasma anemometer.The modeling approach consists in developing an electrical model of the glow discharge in air based on circuit components.The structure of the circuit model is established according to the theoretical analysis and the experimental device.Then the parameters of the circuit model are obtained based on the circuit analysis.Finally,the circuit model is verified by comparing the simulation current with the experimental current.This model takes into account the whole framework of the air glow discharge including the sheath and the plasma area.The built circuit model is feasible and reliable,thus being instructive for the investigation of the glow discharge in air.     

基于多可信度代理模型的尾喷管优化设计

尾喷管是飞行器机体/推进一体化设计中的关键部件之一,直接影响着飞行器的推阻匹配、俯仰力矩配平等特性。为了提高尾喷管优化设计效率,建立基于多可信度代理模型的多目标优化模型。以基于粗网格、无黏模型的CFD 结果作为低可信度数据,以基于细密网格、SST k-ω 湍流模型的CFD 结果作为高可信度数据,将最大化推力系数、升力系数和俯仰力矩系数作为优化目标,构建Cokriging 模型,并结合NSGA-Ⅱ算法得到Pareto 解集。结果表明：以上三个目标分别提升了2.94%、13.0% 和40.6%,误差低于0.5%,并进行了敏感性分析;优化后流场波系结构更为复杂,改变了壁面压强分布规律;与Kriging 模型相比,Cokriging 模型具有相当的预测性能,构建时间成本节省了62%。     

基于强化学习的航空器机场智能静态路径规划

随着人工智能迅速发展以及“智慧机场”的提出,研究人工智能在机场如何有效地辅助机场管制人员,驾驶员指挥航空器在地面滑行具有重要意义。本文提出一种基于强化学习的滑行路径规划方法,构建航空器机场地面强化学习移动模型,并以海口美兰机场为案例采用 Python 内置工具包 Tkinter 进行场面仿真;在此基础上,考虑机场航空器滑行规则,采用 Off-Policy 中 Q-Learning 算法求解贝尔曼方程,实现航空器在 Model-based 环境中进行静态路径规划。结果表明：本文所提方法能够实现停机位到跑道出口智能静态路径规划     

Study on O2 generation and CO2 absorption capability of four co-cultured salad plants in an enclosed system

The ability to generate O₂ and absorb CO₂ of several co-cultured vegetable plants in an enclosed system was studied to provide theoretical reference for the future man-plant integrated tests. Four kinds of salad plants (Lactuca sativa L. var. Dasusheng, Lactuca sativa L. var. Youmaicai, Gynura bicolor and Cichorium endivia L.) were grown in the CELSS Integration Test Platform (CITP). The environmental factors including O₂ and CO₂ concentration were continuously monitored on-line and the plant biomass was measured at the end of the test. The changing rules of O₂ and CO₂ concentration in the system were basically understood and it was found that the O₂ generated by the plants could satisfy the respiratory needs of 1.75 persons by calculation. It was also found that the plants could absorb the CO₂ breathed out by 2 persons when the light intensity was raised to 550 mmol m⁻² s⁻¹ PPF. The results showed that the co-cultured plants hold good compatibility and excellent O₂-generating and CO₂-absorbing capability. They could also supply some fresh edible vegetable for a 2-person crew.     

一种Ku频段全向高增益天线设计

提出了一种工作于Ku频段的宽频带、高增益和H面全向的新型共面波导（CPW）的中心导体和左右地板交叉连接耦合馈电天线结构设计。csTMws。软件仿真结果表明,该结构在具有较小尺寸的同时,能够有效展宽工作频带和提高增益,并保持天线的全向性。利用CSTMWS。软件对天线表面电流的仿真,解释了天线具有宽带和全向高增益辐射的原因：终端加载的三角形单极天线引起CPW中心带条的电流为行驻波电流,使天线获得了较宽的阻抗带宽;10个天线辐射单元的表面电流近似等幅同相,使天线获得了全向高增益的性能。研制出了工作在Ku频段的CPW交叉连接耦合馈电天线并进行了测试。天线印刷于厚度为0．5mm的FR-4环氧树脂板上,其反射系数低于-10dB时的频带为12．4～13．5GHz,相对带宽达8．5％,H面全向最大增益为6．6dBi,表明测试结果与仿真结果吻合较好。整个天线的尺寸仅为81mm×6．1mm,可应用于Ku频段的通信系统中。     

用于复杂装备费用驱动因子筛选的灰色凸关联模型

针对复杂装备费用预测中样本少和费用影响因素繁多的问题,分析以往灰色关联度的缺陷,运用改进的灰色凸关联度建立费用影响因素与费用之间的灰色关联模型。依据灰色凸关联度的大小和接近程度筛选费用驱动因子,利用所选择的驱动因子建立多元回归模型。与已有文献中的方法进行对比,结果表明本文方法具有较高的预测精度,说明改进的灰色凸关联度模型能够诊断复杂装备费用的关键影响因素。     

射流、旋流、出流共同作用下矩形通道换热特性

在放大模型上详细研究了不同雷诺数和出流比下涡轮叶片内冷通道中冲击靶面、出流面和冲击侧面的换热特性.采用热色液晶瞬态测量技术测量通道内部各个面的传热系数,得到以下结论:靶面直接受到射流的第一次冲击,射流形成旋流对出流面进行第二次冲刷,对冲击侧面进行第三次冲刷;靶面受到冲击孔射流的直接冲击,因此换热最强;冲击侧面只受到旋流、横流影响,因此换热最弱;冲击和旋流是通道各个面换热强化的主要原因;换热随雷诺数的增大而增强.出流比对各个面的换热分布及大小也有一定影响.