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滇西北地区典型苔藓植物的引燃特性研究

消防科学与技术 2024年第4期43卷 541-545页

作者：许行健白磊普思伟李世友西南林业大学消防研究所云南昆明650224 云南省森林灾害预警与控制重点实验室云南昆明650224

为研究地表苔藓植物的引燃特性,以滇西北地区广泛分布的多蒴曲尾藓、锦丝藓为试验对象,以香烟和柱香作为引火源,在森林防火紧要期,研究了2种苔藓植物在不同试验条件下的引燃率。利用SPSS Statistics 27.0建立多元线性回归方程,并对该回... 详细信息

为研究地表苔藓植物的引燃特性,以滇西北地区广泛分布的多蒴曲尾藓、锦丝藓为试验对象,以香烟和柱香作为引火源,在森林防火紧要期,研究了2种苔藓植物在不同试验条件下的引燃率。利用SPSS Statistics 27.0建立多元线性回归方程,并对该回归方程进行了检验。分析结果表明,各影响因素对多蒴曲尾藓引燃率影响程度大小排序为热释放速率>火源燃烧速率>苔藓含水率>火源直径>气温>相对湿度,对锦丝藓引燃率影响程度大小排序为苔藓含水率>气温>火源燃烧速率>火源直径>相对湿度>热释放速率。多蒴曲尾藓、锦丝藓模型拟合优度分别为0.820、0.893。通过残差分析得知,多蒴曲尾藓、锦丝藓引燃率预测结果误差分布为±8.895%、±5.845%。研究结果可以为滇西北地区地表可燃物的管理、火险预警等提供依据,为深入开展苔藓植物的火灾风险辨识与评价奠定基础。

关键词：滇西北地区苔藓香烟柱香引燃特性

高中英语教学中项目式学习教学策略在文化意识培养中的应用与研究

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语言与文化研究

语言与文化研究 2024年第1期32卷 103-106页

作者：黄杏坚李文军宁夏师范学院固原756000

文化意识是我国高中英语核心素养内容之一,英语教学过程中需要促进学生的文化意识内化于心,外化于行。本文运用文献分析法了解我国高中英语文化意识培养的内容和困境以及项目式学习的特点,提出项目式学习教学策略运用在高中英语文化意... 详细信息

文化意识是我国高中英语核心素养内容之一,英语教学过程中需要促进学生的文化意识内化于心,外化于行。本文运用文献分析法了解我国高中英语文化意识培养的内容和困境以及项目式学习的特点,提出项目式学习教学策略运用在高中英语文化意识教学中应在正确认识高中英语文化意识培养与项目式学习的本质,准确了解学生的语言能力与认知水平,丰富文化意识培养项目式学习评价方式的基础上,才能有助于实现文化意识外化于行的目标,为培养高中生英语文化意识提供一种可行的实践途径。

关键词：高中英语教学文化意识培养项目式学习文化教学

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SiC高温压力传感器动态性能研究

传感器与微系统 2024年第10期43卷 27-30页

作者：周行健雷程梁庭钟明李培仪中北大学省部共建动态测试技术国家重点实验室山西太原030051 中国航发四川燃气涡轮研究院四川绵阳621000

面向航空发动机测试等恶劣复杂测试环境中动态压力测试需求,本文从芯片及封装结构设计、性能模拟仿真、器件制作工艺及传感器动态性能测试方面对碳化硅(SiC)高温压力传感器动态性能进行了系统研究。仿真结果表明:传感器频响为32.4kHz,... 详细信息

面向航空发动机测试等恶劣复杂测试环境中动态压力测试需求,本文从芯片及封装结构设计、性能模拟仿真、器件制作工艺及传感器动态性能测试方面对碳化硅(SiC)高温压力传感器动态性能进行了系统研究。仿真结果表明:传感器频响为32.4kHz,上升时间为40μs。测试结果表明:传感器的频响不低于5kHz,上升时间为93μs。此传感器具有动态响应频率高、冲击信号响应速度快特点,为航空发动机内脉动压力测量提供了技术支持。

关键词：航空发动机碳化硅高温压力传感器动态性能脉动压力测量

Active fault-tolerant control strategy of large civil aircraft under elevator failures

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Chinese Journal of Aeronautics 2015年第6期28卷 1658-1666页

作者： Wang xingjian Wang Shaoping Yang Zhongwei Zhang Chao School of Automation Science and Electrical Engineering Beihang University

Aircraft longitudinal control is the would lead to catastrophic accident of aircraft. most important actuation system and its failures This paper proposes an active fault-tolerant control （AFTC） strategy for civil aircraft with different numbers of faulty elevators. In order to improve the fault-tolerant flight control system performance and effective utilization of the control surface, trim- mable horizontal stabilizer （THS） is considered to generate the extra pitch moment. A suitable switching mechanism with performance improvement coefficient is proposed to determine when it is worthwhile to utilize THS. Furthermore, AFTC strategy is detailed by using model following technique and the proposed THS switching mechanism. The basic fault-tolerant controller is designed to guarantee longitudinal control system stability and acceptable performance degradation under partial elevators failure. The proposed AFTC is applied to Boeing 747-200 numerical model and simulation results validate the effectiveness of the proposed AFTC approach.

关键词： Active fault-tolerant control Longitudinal control Model following Performance improvementcoefficient Trimmable horizontalstabilizer

中老年2型糖尿病患者甲状腺结节分级的影响因素分析

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中国社区医师 2024年第2期40卷 13-15页

作者：李文佳周兴建湖北医药学院附属襄阳市第一人民医院内分泌科湖北襄阳441000

目的:分析中老年2型糖尿病患者甲状腺结节(TN)分级的影响因素。方法:选取2021年12月—2022年6月湖北医药学院附属襄阳市第一人民医院收治的303例中老年2型糖尿病患者作为研究对象,根据甲状腺影像报告和数据系统TN分级标准分为T1、T2、T3... 详细信息

目的:分析中老年2型糖尿病患者甲状腺结节(TN)分级的影响因素。方法:选取2021年12月—2022年6月湖北医药学院附属襄阳市第一人民医院收治的303例中老年2型糖尿病患者作为研究对象,根据甲状腺影像报告和数据系统TN分级标准分为T1、T2、T3、T4组。比较各组患者临床资料及生化指标,分析中老年2型糖尿病患者TN分级的影响因素,采用Logistic回归分析影响中老年2型糖尿病患者TN分级的独立影响因素。结果:糖尿病病程、身体质量指数(BMI)、内脏脂肪面积(VFA)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)是中老年2型糖尿病患者TN分级的影响因素(P<0.05)。其中T4组VFA、TC高于T1、T2、T3组;T3、T4组糖尿病病程、HOMA-IR高于T1组;T4组LDL-C高于T1、T2组;T4组BMI高于T1组;T3组FINS高于T1组,差异有统计学意义(P<0.05)。糖尿病病程、VFA、TC是中老年2型糖尿病患者TN分级增高的独立危险因素(P<0.05)。结论:随着糖尿病病程的延长、内脏脂肪的积累、TC水平的升高,中老年2型糖尿病患者TN级别增高的风险也升高,临床应予以重视。

关键词：中老年 2型糖尿病甲状腺结节

Aerodynamic Performance of a Flapping Foil with Asymmetric Heaving Motion near a Wall

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Journal of Bionic Engineering 2018年第4期15卷 636-646页

作者： xingjian Lin Shuhao Guo Jie Wu Jingwen Nan Department of Aerodynamics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The effect of asymmetric heaving motion on the aerodynamic performance of a two-dimensional flapping foil near a wall is studied numerically. The foil executes the heaving and pitching motion simultaneously. When the heaving motion is symmetric, the mean thrust coefficient monotonically increases with the decrease in mean distance between foil and wall. Meanwhile, the mean lift coefficient first increases and then decreases sharply. In addition, the negative mean lift coefficient appears when the foil is very close to the wall. After the introduction of asymmetric heaving motion, the influence of wall effect on the force behavior becomes complicated. The mean thrust coefficient is enhanced when the duration of upstroke is reduced. Moreover, more and more enhancement can be achieved when the foil approaches the wall gradually. On the other hand, the positive mean lift coefficient can be observed when the duration of downstroke is shortened. By checking the flow patterns around the foil, it is shown that the interaction between the vortex shed from the foil and the wall can greatly modify the pressure distribution along the foil surface. The results obtained here might be utilized to optimize the kinematics of the Micro Aerial Vehicles （MAVs） flying near a solid wall.

关键词： asymmetric heaving motion wall effect thrust enhancement positive mean lift

Modeling and analysis of mover gaps in tubular moving-magnet linear oscillating motors

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Chinese Journal of Aeronautics 2018年第5期31卷 927-940页

作者： Xuesong LUO Chao ZHANG Shaoping WANG Enrico ZIO xingjian WANG School of Automation Science and Electrical Engineering Beihang University Energy Department-Nuclear Section Polytechnic of Milan

A tubular moving-magnet linear oscillating motor（TMMLOM） has merits of high efficiency and excellent dynamic capability. To enhance the thrust performance, quasi-Halbach permanent magnet（PM） arrays are arranged on its mover in the application of a linear electro-hydrostatic actuator in more electric aircraft. The arrays are assembled by several individual segments, which lead to gaps between them inevitably. To investigate the effects of the gaps on the radial magnetic flux density and the machine thrust in this paper, an analytical model is built considering both axial and radial gaps. The model is validated by finite element simulations and experimental *** of the magnetic flux are described in condition of different sizes of radial and axial gaps. Besides, the output force is also discussed in normal and end windings. Finally, the model has demonstrated that both kinds of gaps have a negative effect on the thrust, and the linear motor is more sensitive to radial ones.

关键词： Air-gap flux density Linear motor Mover gaps Quasi-Halbach array Thrust output Tubular moving-magnet linear oscillating motor(TMMLOM)

高性能建筑结构用钢SN400B热轧工艺研究

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宝钢技术 2024年第3期 66-71页

作者：高兴健郑丽婷杨峰宝钢湛江钢铁有限公司制造管理部广东湛江524000

针对某用户高性能建筑结构用钢SN400B的技术条件,并结合该钢种的高要求应用场合,进行了成分、热轧工艺设计,分析优化出炉温度、终轧温度、卷取温度、终轧与卷取温度差及层流冷却模式等参数,得出结论:较高的出炉温度可以提高强度却不利... 详细信息

针对某用户高性能建筑结构用钢SN400B的技术条件,并结合该钢种的高要求应用场合,进行了成分、热轧工艺设计,分析优化出炉温度、终轧温度、卷取温度、终轧与卷取温度差及层流冷却模式等参数,得出结论:较高的出炉温度可以提高强度却不利于延伸率提升;终轧与卷取温度差越大,强度越高,延伸率越低;密集冷却会造成强度较高而塑性较低,一般冷却可得到强度和塑性较佳的综合性能。

关键词：建筑结构用钢 SN400B 冷却屈强比断裂延伸率

Variable load failure mechanism for high-speed load sensing electro-hydrostatic actuator pump of aircraft

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Chinese Journal of Aeronautics 2018年第5期31卷 949-964页

作者： Cun SHI Shaoping WANG xingjian WANG Yixin ZHANG School of Automation Science and Electrical Engineering Beihang University

This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under highspeed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded.

关键词： Coupling lubrication model Electro-Hydrostatic Actuator (EHA) High-speed pump Partial abrasion Slipper pair Variable load