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According to IEEE Std 802.11p, a fast DOA estimation algorithm of multiple targets based on beam-forming techniques in OFDM radar-communication system for vehicular applications is discussed in this paper. The proposed algorithm has reduced computational complexity utilizing high order power of the inverse spatial covariance matrix without eigen-decomposition. Simulation results demonstrate it is suitable for vehicular application.

A kind of hill-like black silicon have been designed and fabricated by using the combination method of KOH anisotropic etching and gold-assisted HF etching. Pillars array on the surface of a silicon sample was obtained by KOH etching with a SiNx film dots pattern used as a mask. The sample was then etched in the oxidant HF solution catalyzed by Au nanoparticles for 5 minutes. The etched sample appears dark black. This black silicon is orderly hill-like textures in micro-scale with density nanopores on them. It can suppress the reflection to less than 4% in wavelength range from 250nm to 1000nm, and to about 2.5% at the wave number of 2000-4000 cm-1. It also has high additional absorption in IR range.

To change the current phenomenon of “Being an armchair strategist” of photoelectric encoder, a virtual absolute photoelectric encoder is developed using virtual reality techniques. The fundamental theory of absolute photoelectric encoder is expatiated, and then the development strategy is included. Some key technologies and their resolutions are presented in development, including the formation methods for static coded disc and dynamic coded disc. The simulation examples of binary code and gray code are showed subsequently. This paper provides a worthwhile and meaningful assistive tool for the development of absolute photoelectric encoder.

Analyzing some main errors of NC spiral bevel gear honing machine-tool, the elements of geometric error, thermal error and force error etc., which are constructed 39 error sources of the machine by stack method. Based on multi-body system theory, using homogeneous transfer matrix(HTM) method to present six feature matrixes that includes ideal-static matrix, ideal-kinematic matrix, ideal-static translation error matrix, ideal-static rotary error matrix, non-ideal rotary motion error matrix and non-ideal translation motion error matrix, which are built between of adjacent body. Finally, the synthetic volumetric error model of six-axis honing machine-tool is established.

The reasons are analyzed that propeller turbine cannot work properly under littler volume in some seasons, and then a scheme of capacity-decreasing improvement is put forward. Characteristics of design under hyper-normal factors are pointed out. Software of hydraulic design for lower specific speed axial flow runner blades has been developed by Visual Basic and AutoCAD basing on the method of singular point distribution. Finally, an example to demonstrate and explain its use is given in this paper.

To change the current phenomenon of “being an armchair strategist" in the study of DC servo system, the simulation system of that was developed using virtual reality technology. The principle of pulse width modulation was stated. The development strategy of simulation software was introduced. Some key problems and their solutions in system development were put forward, which includes the formation of triangular-wave modulation, calculation of armature current, assurance of duty ratio with average voltage. Finally, an example was given using the virtual DC servo system simulation. This paper provides an assistive tool for the R&D of DC servo system.

The force on dump truck body is telatively complicated, and different unloading working conditions will have effects on the body structure of dump truck. This paper made a modal analysis and feature buckling analysis of the body structure of dump truck under the unloading situation, and also made a nonlinear analysis under the certain circumstances. Through the ANSYS analysis, the body vibration frequency and buckling modal shape was calculated and figured out, and the design of dump truck body was optimized in order to make sure that the stiffness and stability meet the needs.

γ-Unsecalactone was prepared efficiently via the free radical addition reaction with acrylic acid and n-octanol as raw materials. An improved process which used Dean-Stark trap with adding anhydrous Na2SO4as desiccant was developed. Through the orthogonal experiments about the dosages of di-t-butyl peroxide(DTBP) and zinc bromide (ZnBr2), the optimal reaction conditions were as follows:n(DTBP): n(acrylic acid) = 0.160, n(ZnBr2): n(acrylic acid) = 0.050. The yield of γ-unsecalactone based on the optimal reaction conditions reached 71%.

Setup datum of fixture design is an important factor of Numerical Control (NC) machining process planning. Using graph theory of FTG (Feature Tolerance relationship Graph) and DMG (Datum and Machining feature relationship Graph) technology, the feature relationship was proposed to construct a relational table of DMMT (Datum and Machining and Machine Tools) in NC machining setup process. The degree of graph as a discriminant evidence of the machining setup datum was given, so that the machining setup process planning was correctly designed. Combined with the capability of NC machine tools, the unit normal vector of feature facet between the feature datum and machining facet were multiplied to determine the fixture capability, which provide a reasonable proposal of machining setup process for multi-position rotation and multi-piece fixture design. Finally, a case study of machining setup process planning and multi-piece fixture equipment design from corporation was presented to verify the feasibility of the method that was based on the graph theory.

To solve higher-order elliptic gear manufacturing problems, this paper builds the model of hobbing process based on higher-order elliptic gear equation, and researches the graphic simulation technology of hobbing process by using tools (inclined) rack. Four higher-order elliptic spur gears and helical gears with different parameters are simulated by Matlab, to verify the processing model built and the condition of hobbing process can be applied. This work provided the theory foundation for the manufacturing modular of higher-order elliptic gear in CNC System and the reference for its manufacture.

To solve the defect of being not extended for curves in some CAD software, the trend extrapolation principle was imported and the intelligent extension technology for curves was discussed in this paper. The methods of identifying and choosing the trend extrapolation model are provided. Three mathematical models including polynomial curve extension, Gompertz curve extension and exponential curve extension were built, which can be adopted according to the feature points in curves reasonably. This paper has solved the common and core problems, which can be applied to CAD software upgrade or re-development.

To solve higher-order elliptic gear manufacturing problems, this paper researches the pitch curves of higher-order elliptic gear and its transmission features, and creates the judgment method whether hobbing process can be applied. The four-axle three-linkage hobbing model for spur gear and the four-axle four-linkage hobbing model for helical gear are built by using tools (inclined) rack based on four-axle linkage strategy. This work provided the theory foundation for the manufacturing modular of higher-order elliptic gear in CNC System.

In order to have good dephosphorization, it is beneficial to know the proper physical properties, including the melting point and viscosity of slag with fixed lime activity for steel refining, slag foaming and reaction in steel making. A fast way to determine the melting point and viscosity of complex multi-component slags is needed to control the quality of steel. In this study, experimental slag of FetO-CaO-SiO2-MgO-MnO-Al2O3 is obtained with electro slag remelting technique. The liquidus temperature of slag is determined with a video-based contact angle meter recorded with a high-speed camera and verified with an isopleth phase diagram of slag constructed with thermodynamic software FACTSAGE. The viscosity of liquid slag can be estimated with the optical basicity and liquidus temperature obtained from the calculated isopleth phase diagram, then it was compared with the experimental value measured by the rotating torque viscometer. The results indicated that substantial error between the calculated temperature of isopleth phase diagram and the value determined with method of contact angle in high basicity slag. On the other hand, minor difference exists between calculated liquidus temperature and measured temperature in low basicity slag. The viscosity estimated from the optical basicity and liquidus temperature of isopleth phase diagram show the similar behavior. It has good correlation between the calculated value and experimental value in low basicity, however, deviations are found in the range of high basicity.

Fatigue limit measurement is investigated experimentally on the grade B cast steel for Chinese railway freight car bogie frames. Small sample up-and-down test method was employed for the present study. Results reveal that fatigue cracks initiated mostly from the material cast shrinking cavities. Distinct river-like flowers and second cracks appeared on fracture surface in perpendicular to fatigue crack path. Lots of dimples are distributed in transient fracture district to indicate that present material is ductile. Maximum likelihood approach is applied for measuring the probabilistic fatigue limits, in which the limits are defined as the fatigue strengths following normal distribution at an expected fatigue life. Statistical parameters are then estimated by a likelihood function method. A comparison analysis to the existent conventional, Dixon-Mood and Zhang-Kececioglu approaches indicates that the maximum likelihood approach is the approach meeting the definition.