Gull-inspired joint-driven wing morphing allows adaptive longitudinal flight control

Birds dynamically adapt to disparate flight behaviours and unpredictable environments by actively manipulating their skeletal joints to change their wing shape. This in-flight adaptability has inspired many unmanned aerial vehicle (UAV) wings, which predominately morph within a single geometric plane. By contrast, avian joint-driven wing morphing produces a diverse set of non-planar wing shapes. Here, we investigated if joint-driven wing morphing is desirable for UAVs by quantifying the longitudinal aerodynamic characteristics of gull-inspired wing-body configurations. We used a numerical lifting-line algorithm (MachUpX) to determine the aerodynamic loads across the range of motion of the elbow and wrist, which was validated with wind tunnel tests using three-dimensional printed wing-body models. We found that joint-driven wing morphing effectively controls lift, pitching moment and static margin, but other mechanisms are required to trim. Within the range of wing extension capability, specific paths of joint motion (trajectories) permit distinct longitudinal flight control strategies. We identified two unique trajectories that decoupled stability from lift and pitching moment generation. Further, extension along the trajectory inherent to the musculoskeletal linkage system produced the largest changes to the investigated aerodynamic properties. Collectively, our results show that gull-inspired joint-driven wing morphing allows adaptive longitudinal flight control and could promote multifunctional UAV designs.     

基于对数螺旋滑移面的土坡稳定性分析——极向条分极限分析法

鉴于传统极限分析法中协调速度场建立的复杂性。构建了基于对数螺旋滑移面的土坡极向条分破坏模式,解决了协调速度场难以建立的问题。应用塑性力学极限分析原理,采用强度储备安全系数定义法,推导出了基于对数螺旋滑移面的均质土坡稳定性分析——极向条分极限分析法。通过算例验证,该法具有使用简便、可靠性强等优点,对于评价均质土坡的稳定性具有重要的指导意义。     

新型改性氟材料滑动零部件的研制

对新型改性氟材料滑动零部件的组成、加工以及摩擦磨损性能进行了研究，制得具有优异摩擦磨损性能的改性氟材料滑动零部件。     

滑动弧光等离子体技术在化工中应用研究进展

滑动弧光等离子体综合了热平衡等离子体和非平衡等离子体的优点,是一种很有前景的等离子体技术。本文介绍了滑动弧光等离子体的产生过程及反应器结构,并对其在化工领域中的应用进行了综述。     

高压高温处理改色的黄绿色金刚石

继“ＧＥ ＰＯＬ”用高压高温方法将茶色方法将茶色金刚石改成无色之后,同样用此方法将茶色或浅黄色、无色金刚石改成鲜艳的黄绿或绿黄经们没有明显的鉴别特征,无法判别其是天然致色还是人工处理改色。     

OH and O radicals production in atmospheric pressure air/Ar/H2O gliding arc discharge plasma jet

Atmospheric pressure air/Ar/H_2O gliding arc discharge plasma is produced by a pulsed dc power supply. An optical emission spectroscopic(OES) diagnostic technique is used for the characterization of plasmas and for identifications of OH and O radicals along with other species in the plasmas. The OES diagnostic technique reveals the excitation Tx?≈?5550–9000 K, rotational Tr?≈?1350–2700 K and gas Tg?≈?850–1600 K temperatures, and electron density n?(1.1-1.9) ′101 4 cm~(-3) e under different experimental conditions. The production and destruction of OH and O radicals are investigated as functions of applied voltage and air flow rate. Relative intensities of OH and O radicals indicate that their production rates are increased with increasing Ar content in the gas mixture and applied voltage. nereveals that the higher densities of OH and O radicals are produced in the discharge due to more effective electron impact dissociation of H_2O and O_2 molecules caused by higher kinetic energies as gained by electrons from the enhanced electric field as well as by enhanced n e.The productions of OH and O are decreasing with increasing air flow rate due to removal of Joule heat from the discharge region but enhanced air flow rate significantly modifies discharge maintenance properties. Besides, Tgsignificantly reduces with the enhanced air flow rate. This investigation reveals that Ar plays a significant role in the production of OH and O radicals.     

滑翔增程弹稳定储备量的优化设计与仿真

稳定储备量是保证弹丸稳定飞行的前提.本文结合某滑翔增程弹的结构参数和数学模型,对有控滑翔增程弹的稳定储备量进行了优化仿真.通过仿真验证,得出了有控滑翔增程弹稳定储备量的最佳设计范围,对于气动力设计、控制系统的设计及总体结构设计具有重要价值.     

大气滑动弧放电对沙门氏菌的灭活机制及在鸡蛋保鲜中的应用

为了保持鸡蛋的新鲜度、延长其保质期,本研究提出了一种可在室温和大气环境中进行灭菌处理的新型冷杀菌技术,即滑动弧放电技术。首先,将配制好的沙门氏菌液均匀接种在鸡蛋表面,然后使鸡蛋以一定的自旋速率通过等离子体放电区域进行灭菌处理,从鸡蛋表面取得菌样后进行灭活机制研究,并将灭菌处理后的鸡蛋在37℃条件下进行贮藏,通过测定质量损失率和哈夫单位来评价大气放电技术对鸡蛋品质的影响。扫描电子显微镜观察和细胞外蛋白质质量浓度检测结果表明,大气滑动弧放电技术可对沙门氏菌产生有效的刻蚀作用,导致细胞膜破碎和胞内蛋白质泄漏。同时,鸡蛋品质检测表明,滑动弧放电处理组无论作用时间长短,鸡蛋质量损失率增大的程度均比对照组明显,但哈夫单位的降低程度小于对照组,说明大气滑动弧放电可在一定程度保持鸡蛋的新鲜度。     

Decontamination of infected plant seeds utilizing atmospheric gliding arc discharge plasma treatment

In agriculture production,plant health is threatened by pathogens parasitic on seeds;hence,it is necessary to disinfect harvested seeds before germination.In this study,a technique of gliding arc plasma treatment was proposed and investigated.The experiment was conducted to treat Astragalus membranaceus (A.membranaceus) seeds that were artificially infected with Fusarium oxysporum (F.oxysporum).The plasma treatment duration varied from 30 s to 270 s.Direct and indirect treatments were compared to evaluate the inactivation efficiency of the F.oxysporum spores on the surface of seeds.The results indicated that the direct treatment behaved significantly better in disinfection than the indirect way.Meanwhile,experiments of the quantitative assessment of seed germination were also conducted,including the germination rate,the germination potential,and the germination index.The results showed that the inactivation efficiency increased as the plasma treatment time was extended.When the treatment time was 90 s,the inactivation efficiency reached more than 98％.The plasma treatment of 270 s had a complete devitalization of F.oxysporum spores on the surface of the seeds.After the treatment of 30 s and 90 s,the seed germination parameters improved significantly.This study verified the inactivation efficacy of gliding arc discharge plasma under atmospheric pressure.The technique of gliding arc treatment shows advantages of energy saving and adaptation and has the potential to be utilized in industry.     

大机组通流间隙变化的研究

该文着重介绍了用实测高温管道位移并结合理论计算的办法来求出管道对汽缸的作用力的方法 ,而且在实际机组上应用成功。该方法相对于采用高温应变实测管道作用力的办法简易可行 ,易于实施。此外该文还对电站中较多发生的汽缸膨胀不畅故障作了分析研究。图 2表 1