Mutual coupling suppression of aperture coupled microstrip antenna array

A mutual coupling suppression method is proposed for microstrip antenna array by cutting four small semi-circle annular apertures on the metal plate. The structure of antenna array is composed of 2 × 2 four elements. The antenna consists of double layer dielectric, and it realizes circular polarization characteristics by cutting rectangular slot on circular patch in the direction of 45°, by using aperture coupling feeding and reverse feeding principle. There is 90＊ phase difference between adjacent antenna elements. Thus, it cuts off the coupling current field between the elements, suppresses the surface wave and reduces the mutual coupling by cutting four semi-circle annular apertures symmetrically on the metal plate. The simulation results show that after cutting four semi-circle annular apertures, the antenna array coupling coefficients decrease significantly, and the side and back lobe levels are suppressed effectively with the gain of antenna improved. So the proposed method is effective to suppress microstrip antenna array mutual coupling.     

FORMING PRINCIPLE OF TWO SIDE-DIRECTION BURR AND IT‘S PREDICTION IN METAL CUTTING

OgyAbethect The burr is one of the common phenomena occutring in metal cutting OPerations. The mat hematical- mechaniedmodel of two side-direction burr fOrmation and transformation is established with plane stress-strain thcory, based on theorthogonal cutting. The main laws of fOrmation and change of the burr are revealed, and it is confirmed by expedmentresult, which first realizes prediction of the forming and changing of the two sidesdirection burr in metal cutting operation.Key wOrds:Me…     

Intelligent Optimization Methods for the Design of an Overhead Travelling Crane

In design optimization of crane metal structures, present approaches are based on simple models and mixed variables, which are difficult to use in practice and usually lead to failure of optimized results for rounding variables. Crane metal structure optimal design(CMSOD) belongs to a constrained nonlinear optimization problem with discrete variables. A novel algorithm combining ant colony algorithm with a mutation-based local search(ACAM) is developed and used for a real CMSOD for the first time. In the algorithm model, the encoded mode of continuous array elements is introduced. This not only avoids the need to round optimization design variables during mixed variable optimization, but also facilitates the construction of heuristic information, and the storage and update of the ant colony pheromone. Together with the proposed ACAM, a genetic algorithm(GA) and particle swarm optimization(PSO) are used to optimize the metal structure of a crane. The optimization results show that the convergence speed of ACAM is approximately 20% of that of the GA and around 11% of that of the PSO. The objective function value given by ACAM is 22.23% less than the practical design value, a reduction of 16.42% over the GA and 3.27% over the PSO. The developed ACAM is an effective intelligent method for CMSOD and superior to other methods.     

SURFACING ELECTRODE WITH CRACKING RESISTANCE AND WEARABILITY

A new surfacing electrode is developed with cracking resistance and wearability based on high microhardness of TiC and VC, carbides of Ti and V are formed in deposited metal by means of high temperature arc metallurgic reaction. The results show the hardness of surfacing metal increases with the increase of ferrotitanium (Fe-Ti), ferrovanadium (Fe-V) and graphite in the coat. However, when graphite reaches the volume fraction of 11%, the hardness reaches its peak value, and when beyond 11%, the hardness falls off. As Fe-Ti, Fe-V and graphite increase, the cracking resistance of deposited metal and usability of electrode declines. Carbides are dispersedly distributed in the matrix structure. The matrix microstructure of deposited metal is lath martensite. Carbides present irregular block. When using the researched surfacing electrode to continue weld with non-preheated, no seeable crack or only a few micro-cracks can be observed in the surface of deposited metal. The hardness is above 60 HRC. The wear res     

ACQUIRING AND PATTERN RECOGNITION OF SPECTRUM INFORMATION OF WELDING METAL TRANSFER

In order to recognize various metal transfer modes, by the creation of a pattern recognition system for metal transfer mode, five kinds of spectrum signal in gas metal arc welding (MIG, MAG and CO2) are collected and taken as training samples. These samples are pretreated by computer. Several key characteristic parameters of the spectrum signal are creatively extracted, and a corresponding recognition function and a minimum-distance-classifier are constructed. The results show that using this method, the pattern recognition of several kinds of metal transfer mode for the metal gas arc welding can be done successfully. It has good accuracy and recognition precision, basis for controlling the metal gas arc welding metal transfer automatically, and relative important parameters in welding process, such as the frequency of droplet transfer and the approximate diameter of each droplet, can also be obtained.     

Binary Laser Direct Writing System and Its Applications

A new laser direct writing system is introduced and the potential application of the diffractive optical elements (DOE‘ s) fabricated by applying laser direct writing system are presented. The fabrication techniques by applying the laser direct writing are developed. Experimental results have been obtained by applying laser direct writing machine with line width of 5μm and 10μm.     

FLEXIBLE ASSEMBLY FIXTURING LAYOUT MODELING AND OPTIMIZATION BASED ON GENETIC ALGORITHM

There are many welding fixture layout design problems of flexible parts in body-in-white assembly process, which directly cause body assemble variation. The fixture layout design quality is mainly influenced by the position and quantity of fixture locators and clamps. A general analysis model of flexible assembles deformation caused by fixture is set up based on "N-2-1" locating principle, in which the locator and clamper are treated as the same fixture layout elements. An analysis model for the flexible part deformation in fixturing is set up in order to obtain the optimization object function and constraints accordingly. The final fixture element layout could be obtained through global optimal research by using improved genetic algorithm, which effectively decreases fixture elements layout influence on flexible assembles deformation.     

EAF-CSP工艺低碳高强钢中沉淀相的TEM观察

Compact Strip Production(CSP)is a new process for production of hot strips from continuously casting thin slabs by direct charging.The hot strips produced by CSP process undergo different thermo-mechanical process compared with the conventional cold charging process.Supersaturation of microalloy elements in the solid solutions is obvious higher than that in the snips produced by conventional process[1].     

ESTIMATION OF RESIDUAL CONTACT PRESSURE IN HYDRAULICALLY EXPANDED CRA-LINED PIPE

The mechanically bonded CRA-lined pipe is developed to meet the need for corrosion-resistant alloy steel pipe. Residual contact pressure at the interface of lined pipe is important factor that governs the quality of lined pipe. A simplified theoretical method is presented to predict the residual contact pressure created by hydraulic pressure. The calculating equation related hydro-forming pressure to the residual contact pressure between two metal faces is derived. And the validation of the proposed equation is accomplished by comparing its result to those obtained by experimental investigation.     

STUDY ON CONTROL STRATEGY OF CLUTCH STARTING FOR CAR WITH A METAL PUSHING BELT-PLANETARY GEAR CONTINUOUSLY VARIABLE TRANSMISSION SYSTEM

0 INTRODUCTIONA metal pushing belt-p1anetary gear continuouslyvariable transbossion was invented by Macey andVahabzadeh in l987[1]. The most retnarkablecharacteristic of this tusAnssion is a wider rahorange than a conventional metal pushing beltcontinuously variable transndssion, and without areversal planeop gear, the transmission ratio range isconhnuously expanded from positive ratio to negahveratio through a zero ratio. So a metal pushing belt-planetary gear continuously variable tran…     

NC INCREMENTAL SHEET METAL FORMING PROCESS AND VERTICAL WALL SQUARE BOX FORMING

The forming principle and deformation analysis of NC incremental sheet metal forming process as well as the process planning, experiment and key process parameters of vertical wall square box forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to stretch deformation, the deformed region of sheet metal thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. The forming half-apex angle θ and comer radius R are the main process parameters in NC incremental forming of vertical wall square box. According to sine law, a vertical wall square box can't be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. Thus, the parallel line type tool path process method is presented to form the vertical wall square box, and the experiment and analysis are made to verify it.     

Formability of the AMS 5596 Sheet in Comparison with EDDQ Steel Sheet

Some materials form better than others, moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another Configuration. The forming limit of a metal sheet is generally given in terms of the limiting principal strains under different loading conditions and represented by the so-called FLD （forming limit diagram）. In view of the difficulty to experimentally determine the forming limits, many researchers have sought to predict FLD. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. In this study, mechanical properties and the FLD of the AMS 5596 sheet metal was determined by using uniaxial tensile test and Marciniak＇s flat bottomed punch test respectively.     

电解低钛变形铝合金时效组织高分辨电子显微分析

Deformable A1-Mg-Si based alloys are strengthened by heat treatment through solutionizing Mg and Si elements into α-A1 matrix.The aging process of the produced electrolytic low-titanium 6000-type aluminum alloyis analyzed and the corresponding spinodal decomposition microstructure is characterized in the present Paper.     

CONTROL STRATEGY OF A PARALLEL HYBRID CAR WITH A METAL BELT-PLANETARY GEAR CONTINUOUSLY VARIABLE TRANSMISSION SYSTEM

The most remarkable characteristic of a metal belt-planetary gear continuously variable transmission is a wider ratio range and a bigger torque capacity than a conventional metal pushing belt continuously variable transmission. A parallel hybrid car with this transmission system not only can reduce fuel consumption and pollutant emission at a ECE city cycle, but also can keep the motor working in the most efficiency area and can be started by a lower power motor by oneself. At the same time, the continuously variable transmission system can realize the smooth switch between the motor and the engine.     

METAL INERT GAS WELDING OF 2519-T87 HIGH STRENGTH ALUMINUM ALLOY

20 mm thick plates of 2519-T87 high strength aluminum alloy have been welded.The effects of the compositions of filler wires,the heat input and the compositions of shielding gas on the mechanical properties and microstructure of the welded joint have been investigated.The results indicate that finer microstructure,better mechanical properties and higher value of hardness of HAZ can be obtained by using lower heat input.The use of Ar/He mixed shielding gas has several advan- tages over pure Ar shielding gas.With the increase of the proportion of He in the mixed shielding gas, the grain size of the weld metal as well as porosity susceptibility decreases.When the volume ratio of He to Ar reaches 7:3,the porosity and the grain size of weld metal reach the minimum,and the po- rosity can be further reduced by filling some CO_2.     

Ni-Fe-C ALLOY EFFECT ON η PHASE FORMED DURING TIG WELDING OF WC-Co WITH 45 STEEL

Ni-Fe-C filler metal based on WC-30Co/Ni-Fe-C/45 steel is developed using TIG welding method. The weld joints are studied by means of optical microscope, SEM, EPMA, X-rays and micro hardness test etc. The results show that the weld joints of WC-30Co and 45 steel can be obtained by TIG welding using Ni-Fe-C alloys as filler metals. The harmful η phase formed in the joints is M6C, M12C type carbides. The poor carbon content of the W-Co-C system resulted from the carbon diffusion and the high ingredient Fe are the two vital factors inducing to η phase formation. It could be restricted by the addition of carbon element into Ni-Fe alloys.     

NUMERICAL METHOD FOR PREDICTION OF NET-SHAPED BLANK IN MULTI-POINT FORMING OF SHEET METAL

A new numerical method to predict the initial blank geometry from the desired objective shape of parts is presented. Based on the conditions that the deformations in material are most evenly distributed and that the volume remainsconstant, a positive definite functional for blank design is constructed. The functional is minimized by an iterative schemeof finite element, and then the optimal initial configuration is obtained. The method is easy and expedient to use. The results of numerical simulation of forming process and multi-point forming experiments for sheet metal demonstrate thatgood precision is achieved by the proposed method.     

工艺方法对TiNbSn合金微观组织结构的影响

In recent years,some research reports that materials that contained Ni are harmful to human body,because the solvent Ni ions,make man anaphylactic,and even lead to cancer.Therefore,people are trying to explore harmless metal elements to prepare biocompatiable metal materialst[1].     

Weldability of Copper-bearing Aging Steel

The weldability of copper-bearing aging steel is evaluated using calculated cracking susceptibility index Pcm,oblique Y-groove cracking test,heat-affected zone (HAZ) maximum hardness measurement,submerged arc welding (SAW) test and gas metal arc welding (GMAW) test.The results show that this copper-bearing aging steel has low hardenability and cold cracking susceptibility.SAW test of 40 mm thick plate with WS03 wire matched by CHF101 flux reveals that the welded joints obtain high strength and good impact toughness at low temperature.The HAZ has no hardening but there exists a slightly softening phenomenon.Thus,line energy should be limited or controlled strictly to avoid softening behavior in HAZ during SAW.GMAW tests of 12mm and 24mm thick plates using WER70NH wire show that the tensile strength of joints reaches 720MPa,higher than the stipulated strength requirement of base metal.The average impact energy at-40℃ in the welded joints is more than 140J exceeding minimum stipulated requirement by a wide margin.There are no hardening and softening behaviors in the heat-affected zones of GMAW.All weld metals exhibit acicular ferrite (AF) plus small amount of proeutectoid ferrite (PF) structure,of which the former can significantly improve impact toughness of weld metal.The predominant microstructure in coarse grain HAZ is bainite.     

CALCULATION OF FUZZY RELIABILITY IN THE CASE OF RANDOM STRESS AND FUZZY FATIGUE STRENGTH

0 INTRODUCTIONFatigUe Performance data Of metal material is the basic data for the fatigUe reliability design ofmechanical elements or systems. Because fatigUe test data has large scatter, to obtain the accuse oh Ncurve, much experimental data should be collected. HOweVer, only a small amount of sample data isavailable due to the eXPerimental costS or difficulty of collection. The following relationship Eq. (l )acqUired from a saal amount data POint(N, d ) is often imp~ise and a lea…