Search results

The blade is one of the key part of aero engine because its shape precision and surface quality significantly influence the performance, efficiency and reliability of the engine. The blade surface is generally obtained by precision finishing process, which is a repeated work of profile error measurement, profile error calculation and error correction manufacturing. For profile error calculation, the matching of measurement points and ideal blade surface must be firstly performed. However there is few detailed work reported on matching algorithm. In this paper, a new matching algorithm for profile error calculation was proposed. Firstly, the coarse matching method based on characteristics of blade section curves between measurement points and its corresponding ideal section curve was studied. Then the Sigular Value Decomposition (SVD)-Iterative Closest Point (ICP) precision matching method was adopted to improve the matching precision. After that, the weight calculation method was applied to balance the profile errors among different section curves. Simulation work was performed to validate the proposed matching algorithm. Results shows that micrometer-order matching accuracy of the blade section curves could be obtained through the above-mentioned three matching steps.

As basis of the big diameter crystal development, the single crystal automatic growth is the most important technique for system standardization and mass production. In this article, author introduced a new useful way for the single crystal automatic growth of float zone. By setting the growth interval and controlling parameter, PLC controller could automatically control the single crystal growth when the single crystal’s diameter is greater than 50mm. This method applied to the machine system can greatly reduce the fault of manual operation as well as labor intensity. Also it improved the single crystal quality which increases the ability to develop big diameter single crystal in the future.

Secondary electron emission (SEE) processes play an essential role in spacecraft surface charging. It is difficult to study SEE of insulator whose surface cumulates charges by incident electron bombardment because of poor conductivity. This paper investigated the theoretical process of generation, transfer and escape of secondary electrons, and finally the paper presented a mathematical model to calculate the secondary electron emission. We also have improved measurement system to measure total SEE coefficient from dielectric with 1-5 keV electron irradiation which is perfectly fit to mathematical model, and the SEE coefficient with different surface charging is investigated. The results indicate the SEE coefficient decreases with positive charging and increase with negative charging of dielectric surface.

This paper explored the electrochemical oxidation of coking wastewater with Ti/RuO₂-IrO₂ anode. The effects of electrodes connections, area-volume ratio and aeration on the removal efficiency were studied and the ammonia removal mechanism was investigated. The results show that the highest NH₄⁺-N and COD removal efficiency and current efficiency are achieved at the area-volume ratio of 14.44m²/m³ and electrode distance of 0.5cm. Unipolar connection is better than bipolar connection. For electrochemical oxidation of ammonia, the chloride ion is the main factor affecting nitrogen removal. NH₄⁺-N is removed mainly by the oxidation of hypochlorous.

This article summarizes the concept and classification of plasma. The application of plasma technology for the treatment of waste gas, waste water and solid waste are also introduced, and future developments of plasma technology in the field of environmental protection are discussed.

Submerged Entry nozzle is one of the key functional refractories for continuous casting and the safe and efficiency of the continuous casting is directly influenced by the properties of ZrO2-C materials located at the slag line of the submerged entry nozzle. In general, a little anti-oxidants such as SiC, Si or B4C will be introudced into ZrO2-C materials and anti-oxidants also influence the corrosion resistance of ZrO2-C materials. So this paper researched the properties especially the corrosion resistance of ZrO2-C materials with SiC, Si or B4C additions. The results show that the properties of ZrO2-C materials are relate to the composition of ZrO2-C materials and the corrosion resistance of ZrO2-C materials have no obvious relationship with other properties such as apparent porosity, bulk density, et al. The addition of anti-oxidants will all decrease the corrosion resistance of ZrO2-C material. The decreasing degree of corrosion resistance by Si is the most and the decreasing degree of corrosion resistance by SiC is the least. The corrosion resistance of ZrO2-C material with B4C addition is relate to the kind of the mold slag. To obtain the ZrO2-C material with excellent corrosion resistance antioxidants should not be added into ZrO2-C materials.

A new kind of optical fiber corylic resin coating was prepared in this paper. The influence of PVC (pigment volume concentration) to the properties of coatings was studied. The best formula was selected. The best coating was painted on the optical fiber. The relationships of the coating diameter and the distances of the centers of the coating layer and optical fiber were studied. It was found that the circle diameter of coating is greater; the distance of centers of circles is bigger. Finally, the optical fiber with this coating was embedded in resin castings. The cross sections were observed under the same heated situation. The results revealed that the coatings embedded in composites used in large aircraft had no change when it was heated. This kind of coating did not need ultraviolet light or heating, and it’s easy to control the thickness and roundness of the coating by controlling the speed of pulling out the optical fibers. This type coating is a kind of simple heat-resistant coating embedded in composite materials used in the large aircraft.

The traditional cars consume high energy and the energy of vibration is wasted. To solve these problems, a new energy recovery damper was designed by analyzing the principle of vibration energy recovery and the advantages of electroactive acrylic elastomer materials. The three-dimensional modeling was finished for the mechanical structure of the energy recovery damper. As an important constituent part of vehicle suspension system, the energy recovery damper was a nonlinear vibration system which contained elastic force and damping force. The system could generate random vibration with the drive of the sources such as pavement roughness and engine. The vibration energy can be recycled and stored into vehicle battery by the energy recovery damper. The energy could be saved by changing the vibration energy into electric energy. The energy recovery damper has the advantages of simple structure and high efficiency.

Reliability design is a new design theory and design methods with the modern science and technology developed. Food waste processing equipment is a new and efficient equipment used for food waste recycling. This paper briefly describes the design of mechanical reliability, and by describing the characteristics of food waste, described in the food waste processing equipment design, the need for the use of reliability design. To provide some basic reliability analysis for the future design of equipment.

TiO₂ photocatalysts doped by Fe³⁺ with different contents were prepared by adsorption phase synthesis. The influence of Fe³⁺ doping with various concentrations on the crystallization of TiO₂ was explored by XRD. Then photodegradation experiments of methyl-orange were employed to evaluate the activity of these photocatalysts. The results indicated that the crystallization of TiO₂ was restricted after doping, due to replacement of Ti⁴⁺ in TiO₂ lattice structure by Fe³⁺ ions. And the restriction became stronger with doping concentration of Fe³⁺ ions increasing. Since radius of Fe³⁺ was close to Ti⁴⁺, the restriction of Fe³⁺ doping on crystallization of TiO₂ was so stronger that the photocatalytic activity of most TiO₂ doped with Fe³⁺ ions was lower than that of TiO₂ without doping.