航空数据库适航审定政策研究

航空数据库（Aeronautical Database）作为实现航空器导航、避障和指引功能的重要部分，其数据结 构遵循特定格式的标准。航空数据库的质量将直接影响到航空器的运行安全。当前民航适航体系针对原始数据 及后续处理过程的质量体系的审定缺乏实际经验，给机载设备和飞机运行的适航性带了挑战。本文首先介绍当 前世界范围内航空数据库适航管理的办法及技术标准，再结合当前国内航空数据库的审定的现状，提出一种可 行的中国航空数据库适航审定的政策建议，供国内各类航空数据库的研制单位及审查方参考。     

Cortical Microtubule Reorientation and Its Relation to Cell Surface Texture of Epidermal Cells of Arabidopsis Thaliana Hypocotyls under Simulated Microgravity Conditions

Gravitropic curvature growth of Arabidopsis hypocotyls mainly occurred in the rapid growing Elongation Zone (EZI), not in the slow-growing Elongation Zone (EZⅡ). By examining reorientation of Microtubules (MT) and phenotype of the cell wall in the EZI and the EZⅡ of Arabidopsis hypocotyls under normal gravitational condition, it is found that MTs in the rapid growing epidermal cells were mainly in the transverse direction, while those in the non-growing epidermal cells were in the longitudinal directions. However, this difference in cortical MT arrays between the EZI and EZⅡ cells disappeared when the seedlings were exposed to the simulated microgravity condition on a horizontal clinostat. Field emission scanning electron microscopy revealed that the surface texture of epidermal cells, like the direction of the MT, in the EZI and the EZⅡ also became similar when exposed to the simulated microgravity condition. This result indicated that simulate microgravity could modify the potential differentiation between the EZI and the EZⅡ by affecting the orientation of cortical MT in the epidermal cells.      

基于ANCF的松弛绳索动力学建模与仿真

传统绝对节点坐标方法(ANCF)绳索模型是基于梁单元建立的,其不能反映纤维绳索的不可抗压和松弛特性。考虑纤维绳索初始松弛余量,给出了绳索非线性轴向应力-应变关系。绳索在松弛状态下轴向力接近于零,在张紧状态下表现出线弹性特性。在此基础上,采用绝对节点坐标方法推导了松弛绳索动力学模型。通过静力学和动力学仿真,将传统绳索模型和松弛绳索模型进行对比,结果表明:在重力及不同集中载荷作用下,松弛绳索相比于传统绳索都具有更大的变形;分析移除集中载荷后绳索的动力学响应可知,传统绳索在振动过程中始终处于张紧状态,且绳索上各点振动同步,而松弛绳索会在张紧和松弛状态之间不断转换,绳索上各点的振动存在相位差,能够更好地反映绳索在松弛状态下的动力学特性。     

电磁气动阀四机集成设计

针对某空间飞行器对轨控发动机控制阀体积及重量的要求,统筹考虑气液路供应、4台发动机、氧化剂及燃料贮箱的安装要求,设计了新颖的电磁气动阀四机集成结构。经仿真分析及试验实测,结果表明:电磁气动阀四机集成结构具有设计巧妙、性能优良的特点。     

JJG 860-2015《压力传感器(静态)检定规程》浅析

介绍了JJG 860-2015《压力传感器(静态)检定规程》的主要变化,就检定设备的选择、特殊压力传感器的检定方法等对规程进行浅析,结合测试实例论述了新增传感器零点漂移和周期稳定性两个性能指标的必要性,并对规程的进一步完善提出了建议。     

国外舰载飞机着舰进近适配性评估技术研究

通过对国外舰载飞机在着舰进近下滑中的操纵需求分析,提出舰载飞机着舰进近适配性的评估要求。在评估要求的基础上针对飞机在进近适配性方面相关的特性给出相应的飞行试验方法和分析方法,初步建立舰载飞机着舰进近适配性评估技术和方法。     

Optimal parity vector sensitive to designated sensor fault

Based on the parity space construction and the orthogonal constraint condition of parity vector, the approach of fault detection and isolation using optimal parity vector is presented. Its main idea is to design a performance criterion similar to the criterion presented by Zhang and Patton (1993), but most sensitive to the designated sensor's fault and least sensitive to other sensor's fault and unknown inputs such as noise. Through the Monte-Carlo simulation, it is shown that the proposed approach of choosing optimal parity vector greatly increases the ability of fault detection and the effectiveness of fault isolation is better than the generalized likelihood test (GLT) approach     

关于完善我国税务稽查的若干思考

本文针对我国税务稽查中存在的问题,进行了深刻的分析,并提出了解决的对策。     

High-efficiency aircraft antiskid brake control algorithm via runway condition identification based on an on-off valve array

The aircraft antiskid braking system is an important hydraulic system for preventing tire bursts and ensuring safe take-off and landing. The brake system adjusts the force applied on the brake discs by controlling the brake pressure. Traditional aircraft antiskid braking systems achieve antiskid performance by controlling the braking pressure with an electrohydraulic servo valve. Because the pilot stage of an electrohydraulic servo valve is easily blocked by carbonized hydraulic oil, the servo valve would become a dangerous weak point for aircraft safety. This paper proposes a new approach that uses an on-off valve array to replace the servo valve for pressure control. Based on this new pressure control component, an efficient antiskid control algorithm that can utilize this discontinuous feature is proposed. Furthermore, the algorithm has the ability to identify the runway circumstances. To overcome the discontinuity in the process of using an on-off valve array, the Filippov framework is introduced. The conditions of convergence of the system are also discussed. The results of the digital simulations and the hardware-in-the-loop (HIL) braking experiments are used to verify the efficiency and stability of the proposed control algorithm. The method also proves that the on-off valve array can replace the servo valve perfectly as a new type of antiskid braking pressure control component.