激励力对发动机机体表面振动影响的仿真分析研究

发动机工作时内部主要激励力包括燃气爆发压力、活塞连杆等运动件惯性力、配气机构激励力和活塞敲击力等,机体表面振动是发动机内部各种激励力叠加的响应,构成成分复杂。通过AVL EXCITE软件,建立有限元与多体动力学联合仿真模型,计算获得不同激励力作用下的机体表面振动信号数据,再通过时域、频谱分析,研究激励力对机体表面振动的影响,从而解决真实发动机难以进行相关试验测试分析的问题,为发动机振动分析与优化设计提供可靠的依据。

区域投影声束追踪法及其飞机表面载荷预测

舱内噪声影响乘客乘坐飞机的舒适性,同时噪声是影响民用飞机获得适航证和市场认可的重要因素之一。在飞机低噪声设计开发中,机体表面高频声载荷的数值预测方法起着至关重要的作用。使用区域投影声束追踪法进行飞机表面的声载荷预测可以解决经典几何声学方法在大空间下计算的不适应性。经典声线追踪法对不同空间下的声线接收域有着严格的要求,文章将飞机模型的单元网格作为模型的单个接收域,将接收域向声源包络面上投影确定接收域应该接收的声能量密度,通过与经典算法在标准模型下的计算结果对比,定量分析了改进方法与经典方法在计算结果与计算效率上的优劣;通过对比商业软件的声线法模块在飞机模型下的计算结果,验证了改进计算方法计算结果的准确性。

EBPVD金属/陶瓷微层复合材料的研究与应用

介绍了电子束物理气相沉积 (EBPVD)法制备微层复合材料的优点 ,详述了其四种不同材料体系的设计思想 。

Development of a Thermal Fogger-specific Sedimentation Stabilizer

In order to solve the drifting away of thermal fog droplets during thermal spraying and the incompatibility between fog droplet carrier and conventional com- mercial agro-chemicals, the fog droplet carrier, surfactant, condensation nucleus ma- terial and antifreeze, dispersant, thickener and defoamer were screened and assem- bled to develop a thermal fog sedimentation stabilizer in this study, thereby provid- ing technical support for application and promotion of thermal spraying technology in pest and disease control in crops.

拖拉机故障判断

1看 1.1看烟色发动机正常情况下排出的废气应当是无色透明的或接近无色透明的.如果排出的废气有色或不透明,就表明其中含有某种液体微粒或固体微粒.例如,排气冒蓝烟,说明发动机有烧机油现象;排气冒白烟,说明排气中含有水分或还没能燃烧的灰白色的油雾.

Anti⁃icing/De⁃icing Mechanism and Application Progress of Bio⁃inspired Surface for Aircraft

Icing on the surface of aircraft will not only aggravate its quality and affect flight control,but even cause safety accidents,which is one of the important factors restricting all-weather flight.Bio-inspired anti-icing surfaces have gained great attention recently due to their low-hysteresis,non-stick properties,slow nucleation rate and low ice adhesion strength.These bio-inspired anti-icing surfaces,such as superhydrophobic surfaces,slippery liquid-infused porous surfaces and quasi-liquid film surfaces,have realized excellent anti-icing performance at various stages of icing.However,for harsh environment,there are still many problems and challenges.From the perspective of bioinspiration,the mechanism of icing nucleation,liquid bounce and ice adhesion has been reviewed together with the application progress and bottleneck issues about anti-icing in view of the process of icing.Subsequently,the reliability and development prospect of active,passive and active-passive integrated anti-icing technology are discussed,respectively.

Mixed P3HT/PCBM Organic Thin-Film Transistors： Relation between Morphology and Electrical Characteristics

The mixed P3HT （poly（3-hexylthiophene）） and [6,6]-PCBM （phenyl C61-butyric acid methyl ester） organic thin films were investigated for electronic structure using UV-Vis spectrophotometer and PESA （photo-electron spectroscopy in air）. Furthermore, ESR （electron spin resonance） and AFM （atomic force microscopy） were used to investigate the surface morphology and molecular orientation, respectively. ESR analysis indicated the molecular orientation of the P3HT crystalline in the blend thin films, which the crystalline oriented normal to the substrate with distribution of 35°. AFM images indicated that the surface morphology of P3HT film was affected by the presence of PCBM nanoparticles. Solution-processed OTFTs （organic thin-film transistors） based on P3HT/PCBM blend thin film in a top source-drain contact structure was fabricated, and the electrical characteristics of the devices were also investigated. A unipolar property with p-channel characteristics were obtained in glove box measurement.

Action Mechanisms of Arbuscular Mycorrhizal Fungi in Phosphorus Uptake by Capsicum annuum L.

A pot experiment was conducted to investigate the action mechanisms phorus （P） uptake of Capsicum annuum L. in a sterilized fossil Oxisol of arbuscular mycorrhizal （AM） fungi in phos- Three P levels of 0, 10 and 200 mg kg-1 soil （P0, P10 and P200, respectively） without and with AM fungal inoculation were applied as Ca（H2PO4）2-H20. Shoot dry matter yields and shoot P uptake increased significantly （P 〉 0.05） by the inoculation of AM fungi at P0 and P10. Root length and P concentration in soil solution increased with the inoculation of AM fungi but the root：shoot ratio decreased or remained constant. Around 50% roots of inoculated plants were infected by AM and the external hyphae amounted to 20 m g^-1 soil at P10 and P200. The hyphae surface area of the infected root cylinder amounted to 11 and 2 cm^2 cm^-2 root at P0 and P10, respectively. The increased P uptake of inoculated plants was mainly because of an up to 5 times higher P influx of the infected root. Model calculations showed that the root alone could not have achieved the measured P influx in both infected and non-infected roots. But the P influx for hyphae calculated by the model was even much higher than the measured one. The P uptake capacity of hyphae introduced in the model was too high. Model calculations further showed that the depletion zone around roots or hyphae was very narrow. In the case of the root only 7% of the soil volume would contribute P to the plant, while in the case of hyphae it would be 100%. The results together with the model calculations showed that the increased P uptake of AM inoculated plants could be explained partly by the increased P concentration in the soil solution and by the increased P absorbing surface area coming from the external hyphae.

Metal-organic framework film for fluorescence turn-on H2S gas sensing and anti-counterfeiting patterns

Hydrogen sulphide(H2 S)is a common air pollutant,which is produced in various industry processes.Therefore,it is of crucial importance to detect H2 S in real time.Many fluorescent sensors were reported aiming at detecting H2 S in solution;however,the fluorescence sensing of gaseous H2 S has not yet been reported.In this work,we utilized the post-functionalized fluorescent film,MIL-100(In)@Eu3+/Cu2+film,realizing fluorescence turn-on sensing of gaseous H2 S at room temperature for the first time with the limit of detection as low as 0.535 ppm,which is comparable to some reported fluorescent probes for S2-ions and semiconductor based gaseous H2 S sensors.The sensor was designed due to the strong affinity of H2 S with Cu2+.With the formation of CuS,the"antenna effect"between the ligand and Eu3+recovered,resulting in the fluorescence turn-on of Eu3+emission.Additionally,we proposed a new method to realize multi-colour anti-counterfeiting patterns with lanthanide ions ink,taking advantage of the extraordinary smooth surface and uncoordinated carboxylate groups within the MIL-100(In)film.

Reusing of transmitted light by localized surface plasmon enhancing of Ag nanoparticles in organic solar cells

Silver nanoparticles(Ag NPs)are synthesized with chemical method,which are introduced into the traditional organic photovoltaic(OPV)structure.The experimental results show that both the optical and photoelectric properties are en-hanced because of localized surface plasmon(LSP)effects of Ag NPs.The advantage of adding Ag NPs behind active layer in incident direction is discussed.We believe this route can avoid absorption shadow and enhance the reusing of transmitted light of active layer.The average short-circuit current(J SC)of the optimum device can be raised from 9.23mA/cm2 to 10.84mA/cm2,and the energy converting efficiency(PCE)can be raised from 3.22% to 3.85%.

How different are the surfaces of semiconductor Ag_(2)Se quantum dots with various sizes?

The surface of nanocrystals plays a dominant role in many of their physical and chemical properties.However,controllability and tunability of nanocrystal surfaces remain unsolved.Herein,we report that the surface chemistry of nanocrystals,such as near-infrared Ag_(2)Se quantum dots(QDs),is sizedependent and composition-tunable.The Ag_(2)Se QDs tend to form a stable metal complex on the surface to minimize the surface energy,and therefore the surface chemistry can be varied with particle size.Meanwhile,changes in surface inorganic composition lead to reorganization of the surface ligands,and the surface chemistry also varies with composition.Therefore,the surface chemistry of Ag_(2)Se QDs,responsible for the photoluminescence(PL)quantum yield and photostability,can be tuned by changing their size or composition.Accordingly,we demonstrate that the PL intensity of the Ag_(2)Se QDs can be tuned reversely by adjusting the degree of surface Ag^(+) enrichment via light irradiation or the addition of AgNO_(3).This work provides insight into the control of QD surface for desired PL properties.