3D imaging application in the studies of micro air vehicles

3D techniques are increasingly used in aerospace industry to improve quality and performance of aircrafts. This paper presents a 3D imaging technique for studying the aerodynamic shape and flight performance of micro air vehicles. 3D stereoscopic vision, based upon stroboscopic imaging, was utilized to obtain the 3D information of the aircraft's flexible aerodynamic surface. The aircraft models with deformable aerodynamic shape were designed and tested in a purpose-built wind tunnel experimental environment. After calculation of SIFT feature points and subdivision of triangular meshes, deformable surface of the aircraft's aerodynamic shape was represented. The aircraft's 3D visualization was used for analyzing unsteady deformation in the aerodynamic shape under external airflow disturbances. The results, together with aerodynamic forces measured in the experiment, will be useful to improve the flight performance and disturbance resistance ability of micro air vehicles.     

某地铁列车空调制冷系统的仿真与优化

我国的地铁建设正处于高速发展期,但目前典型地铁列车空调制冷系统的能效比只有2.2～2.3,远低于同类工况下住宅空调制冷系统的能效水平。针对此问题,先建立了某地铁空调制冷系统模型,仿真与系统测试结果吻合良好。然后通过详细的仿真分析,改进蒸发器和冷凝器的制冷剂流路设计、采用小排量高能效比压缩机等方法,使得系统在冷量和成本基本不变的情况下能效比提升了21.7%。最后,研究了制冷剂R410A替代R407C的系统性能变化,系统能效比可进一步提升11.3%,达到3以上。该研究方法及结果对于设计高效节能的地铁列车空调制冷系统具有参考价值。     

空气压缩式制冷在燃气轮机气垫船上的应用

根据空气压缩式制冷循环原理,分析了利用燃气轮机气垫船上的已有装置-燃气轮机引气装置及其它附属部件组成制冷系统的可能性,并对其中的热交换器的性能加以讨论.结果表明:与常规压缩式制冷系统相比,这套制冷系统的重量大大减轻,提高了船内人员的舒适性,而且有利于气垫船的航行.     

螺杆空压机两级压缩节能技术分析

简介双螺杆空压机与两级螺杆空压机的结构和运行特点,由于两级螺杆空压机采用了两级串联压缩工艺、中间喷油冷却装置和大直径螺杆等,节能效果明显。通过实例计算,得出两级螺杆空压机比双螺杆空压机节能15%。     

毛细管气相色谱测定室内空气中苯系物分析误差预评价

目的:评价毛细管气相色谱测定室内空气中苯系物的分析误差。方法:对空白溶液、0.1c标准溶液、空气样品、加标空气样品,采用精密度和偏性质量控制程序进行质控试验。结果:4种试样的批内批间变异分析(F相似文献   

“Wiring” Fe‐Nx‐Embedded Porous Carbon Framework onto 1D Nanotubes for Efficient Oxygen Reduction Reaction in Alkaline and Acidic Media

This study presents a novel metal‐organic‐framework‐engaged synthesis route based on porous tellurium nanotubes as a sacrificial template for hierarchically porous 1D carbon nanotubes. Furthermore, an ultrathin Fe‐ion‐containing polydopamine layer has been introduced to generate highly effective FeN_xC active sites into the carbon framework and to induce a high degree of graphitization. The synergistic effects between the hierarchically porous 1D carbon structure and the embedded FeN_xC active sites in the carbon framework manifest in superior catalytic activity toward oxygen reduction reaction (ORR) compared to Pt/C catalyst in both alkaline and acidic media. A rechargeable zinc‐air battery assembled in a decoupled configuration with the nonprecious pCNT@Fe@GL/CNF ORR electrode and Ni‐Fe LDH/NiF oxygen evolution reaction (OER) electrode exhibits charge–discharge overpotentials similar to the counterparts of Pt/C ORR electrode and IrO₂ OER electrode.     

几种控制方式在空调系统运行节能中的应用

综述了前馈控制、模糊控制、神经网络在中央空调系统节能控制方面的特点、研究及应用现状,从系统化节能需求出发,概述了LonWorks的特点及其在空调节能控制系统中的应用。     

带有喷气冷却的R32风冷单元式空调机性能实验研究

针对带喷气冷却和不带喷气冷却的R32风冷单元式空调机进行实验研究。研究发现,虽然采用喷气冷却导致系统的冷凝压力较高且系统性能系数降低,但可以有效提高系统制冷量,降低压缩机的排气温度,有效提高系统的可靠性。     

浅议辐射供冷空调系统在工程中的应用

根据对辐射空调系统特性的分析,介绍了其在实际工程中与其它空调系统的联合运行方式,包括与置换通风、独立新风和地源热泵等系统的联合应用,最后展望了辐射空调系统今后发展的前景,并提出了相应的建议。     

FTIR和光谱差减法的大气质量检测

针对大气质量检测的多组分定量分析,本文提出利用傅里叶变换红外光谱（FTIR）技术与光谱差减相结合的气体定量方法。该方法是根据迈克尔逊干涉原理与朗伯．比尔定律,采用怀特型长光程气体池与FTIR光谱仪相结合的方式来测得痕量气体的红外光谱,最后利用光谱差减法反演出气体浓度。为了避免背景环境的干扰（主要是避免水和CO2吸收峰的干扰）,选择了在某些特殊波段内的待测气体吸收峰进行分析。本文分别对CO,SO2,NO2,NO和CO2气体进行了定量分析,相应的最佳观测波段依次为：2250～2020cm^-1,1230～1070cm^-1,2940～2840cm^-1,1965～1775cm^-1,668．24cm^-1。实验结果表明,经浓度反演相对误差可达到10％以内。