为了探寻激光功率对熔覆层组织与性能的影响,设计4种不同激光功率在27SiMn钢表面进行Fe-Cr-Ni熔覆层制备,利用超景深显微仪、显微硬度计、摩擦磨损试验机对熔覆层的显微组织、硬度、磨损量及摩擦因数进行了研究.结果表明,4种激光功率下的试件熔覆层均无气孔裂纹等缺陷,激光功率为1800 W时所制备试件的枝晶生长方向较为一致,激光功率为2400 W时所制备试件熔覆层中部的胞状晶和二次枝晶晶胞较为细小致密;随着激光功率增加,熔覆层的熔宽、熔深和稀释率逐渐增大,而熔高则先增大后减小;熔覆层硬度受激光功率影响较小,但增大激光功率可以提高热影响区硬度;激光功率为2400 W时所制备试件的平均摩擦因数最小、磨损量最少、磨损深度最小,其耐磨性能优良.

Process parameters are the key factors determining the quality of laser welding aluminum alloys. Therefore, to ensure good weld morphology quality, a combined response surface methodology and particle- swarm optimization (RSMPSO) algorithm was proposed to explore the optimal process parameters to laser weld 2 mm-thick 6061 aluminum alloy sheets. The experimental design of the fiber laser welding was performed using Desk-Expert 10. 0 software. In response to weld collapse and sheet bending, multiple linear regression of the welding parameters was established. The effects of various process parameters on the welding quality were analyzed, and the particle- swarm intelligence algorithm was used for optimization. The results show that under the experimental conditions of this study, the scanning speed and defocusing have a strong influence on the weld collapse, and the laser power and scanning speed have a great influence on the sheet deformation. The optimal process parameters are laser power, scanning speed, and defocusing amount of 2629 W, 6. 85 mm/s, and -0. 18 mm, respectively. Under these parameters, the collapse depth and bending of the 6061 aluminum alloy sheet are only 85. 66 mu m and 1. 2 mm, respectively, indicating that the parameters obtained via this algorithm can effectively improve the welding quality.

工艺参数是保证激光熔覆修复阀门类零件质量的关键因素.以激光功率、扫描速度、送粉速度、离焦量为自变量,熔池深度、显微硬度、稀释率为优化目标,基于正交试验研究了工艺参数对40Cr基材上熔覆Fe基合金粉末性能的影响规律.采用逐步回归分析建立了稀释率、熔池深度、显微硬度的回归方程,最后通过NSGA-Ⅱ智能算法进行优化,得到了最优工艺参数并进行了试验验证.结果表明:熔覆层稀释率及显微硬度的主要影响因素为送粉速度,而对熔池深度影响最大的因素为激光功率,在激光功率2182?W、扫描速度17.2?mm/s、送粉速度18.4?g/min、离焦量1.86?mm时,熔覆层形貌大为改善,稀释率为20.3％,熔池深度为373?μm,显微硬度提高了21.7％,修复质量得到了有效提高.

残余应力直接影响激光熔覆修复机械零件的结构强度和安全性能,为了掌握损伤轴面激光熔覆修复后的残余应力分布情况,以40Cr钢零件轴为基材,Ni60自熔合金粉末为熔覆材料,采用脉冲激光熔覆工艺制备零件轴表面修复试件,利用盲孔法对零件轴修复试件进行残余应力分布特性分析.结果表明,在轴面激光熔覆的镍基合金修复层中产生了不可忽略的残余拉应力,高应力区位于熔覆层始末两道上;轴线方向检测点上X方向残余应力呈"M"形分布,Y方向残余应力呈"Λ"形分布,σx值较高,接近基材屈服强度的45.9％,而圆周方向检测点的X方向和Y方向残余应力相对稳定,最大拉应力约为200 MPa;激光扫描路径对轴面熔覆层的残余应力值的影响大、分布形状的影响小,螺旋路径熔覆产生的残余应力值较低,更适合圆周面修复,但熔覆层始末两道边沿处的残余应力比中间部位高,有必要采取适当措施进行消应力处理,以获得优良的修复效果.

： In order to avoid the microcrack defects, the thermal-mechanical coupling problem is analyzed adopting a numerical approach during the wear shaft surface laser cladding. The mathematical model of nonlinear transient analysis is established based on the wear surface laser cladding experiment, then an ordered discrete grid algorithm is using to realize three-dimensional finite element model of the shaft surface laser cladding process. The transient thermal- mechanical cycle and its coupling problem during multi-tracks cladding metal powder ring deposition process are solved by a developed subprogram with ANSYS parametric design language (APDL) and the finite element kill and birth technique. The distribution of temperature and thermal stress are obtained in the cladding process. Simulation results indicate that temperature gradients of the molten pool are larger and the highest temperature is 2035.99 ℃ which located in the adjacent area of spot center location. Transient temperature variations of the nodes on different cladding tracts are similar and arrive behind the load time. The cladding residual stress associated with temperature gradient and the peak residual stress(about 279 MPa)occurs in substrate metal adjacent heat affected zone (HAZ), which are in a good agreement with experimentally obtained results. The paper has a guiding significance to process optimization of the wear shaft surface laser cladding.

This paper introduces the research and development of nanoimprint lithography technology and analyzes the three common lithography processes , hot press printing ( Hot embossing lithography , HEL) , UV curing stamping ( Ultra violet nanoimprint lithography , UV-NIL) and Micro Contact stamping ( Micro Con-tact printing ,μ-CP) .For getting better quality , the method and main factors of nanoimprint lithography pat-tern are discussed , for the purpose of deepening the understanding of the nanoimprint lithography process ( mould fabrication , stamping process and pattern transfer ) , solving some key problems of the nanoimprint li-thography process , and providing the necessary scientific basis for research and development the new nanoim-print lithography technology .

The invalidation of harmonic deive is mostly the fatigue rupture of the flexspline,ger the data of flexspline by finite element analysis. Model is a base of analysis,the results effect on analysis accuracy. The flexspline ’s model using of Pro/E, the paper introduced modeling process of flexspline for mechanical analysis

The invalidation of harmonic drive is mostly the fatigue rupture of the flexspline.The finite element method based on contact is put forward,the mathematical model is set up and the modal analysis is carried out,and the first ten natural frequencies of the flexible wheel are got.The study can give some reference for the improvement of harmonic drive.

To reconstruct the evolution process of tectonics and paleoenvironment during the late-Cenozoic time in West Kunlun area,clay mineralogy of the molasse sediments of the foreland basin of West Kunlun mountains were investigated using X-ray diffraction(XRD) and scanning electron microscopy(SEM) methods.The results show that clay minerals in sediments of 8-1.8Ma B.P.are mainly illite and smectite,with minor chlorite and kaolinite,while their relative contents and illite crystallinity change apparently along the profile.Illite content and its crystallinity are both notably high,and the content of smectite is low,with minor kaolinite occurring throughout the sediments of 8 ～ 3.5 Ma B.P.The content of smectite increases sharply while the content of illite,as well as the illite crystallinity,decreases,and no kaolinite is present in the period of 3.5 ～ 3.3Ma B.P.Clay mineral indices of the period of 3.3 ～ 2.8 Ma B.P.are similar to those of 8 ～ 3.5 Ma B.P.,and which of the period of 2.8 ～ 1.8 Ma B.P.are similar to those of 3.5 ～ 3.3 Ma B.P.It is concluded that changes in clay mineralogy of the Yecheng sediments was dominantly controlled by the changes of source rocks and,to some extent,by changes in climate around the area.The uplift of the West Kunlun is uneven and stepwise according to clay mineralogy of sediments.There were three times structural uplift events in the west Kunlun area,which had occurred around 3.5 Ma B.P.,3.3 Ma B.P.and 2.8 Ma B.P.,respectively.In addition,an arid episode occurred around 2.5 Ma B.P.in the region.

Faults are well developed in 4th structural belt of Nanpu Depression,among which there are not only deep faults linking hydrocarbon source rocks and traps,but also the associated faults that can reach shallow reservoirs.Based on the analysis results of seismic,logging and oil-testing data,the spatial distribution of faults have been analyzed,the growth index of faults and Shale Gouge Ration(SGR) are calculated.In addition,evaluation has been done on the activity of faults,the sealing and transportation capability of faults.Combined with the study on the matching relationship between the fault activity with hydrocarbon generation and expulsion,analyzed with modeling results,the relationship between faults with hydrocarbon migration and accumulation,and the control roles of the these faults on hydrocarbon migration and accumulation have been studied thoroughly.Finally,based on the analysis of the typical oil and gas reservoir profiles,the model of hydrocarbon migration and accumulation of the 4th structural belt has been constructed.

The temperature measurement system is based on the combination of virtual instrument and intelligent apparatus.Compared with the universal data acquisition cards,this system reduces the equipment investment greatly,and can achieve remote data collection,which makes the fault feature extraction easier.

The sandstone reservoirs in the Chaluhe depression,Yitong Basin,Jilin have moderate to low porosity and low permeability.The types and contents of clay minerals tend to have an important effect on the physical properties of the hydrocarbon reservoirs.The results of SEM and X-ray diffraction analysis have revealed that there is a negative correlation between the absolute contents of clay minerals and their porosity and permeability.The permeability tends to decrease in response to the increase of the contents of illite,and to increase in response to the increase of the contents of kaolinite.The porosity is less variable in response to the relative contents of the clay minerals.