响应面分析法优化低碳钢薄板激光切割工艺参数

为了研究光纤激光加工工艺对Q235低碳钢薄板切割质量的影响，采用500 W光纤激光切割机对0.7 mm厚低碳钢板切割质量影响规律进行了研究。采用中心复合设计(Central Composite Design, CCD)进行实验设计，使用超景深显微镜对切割试样的切缝宽度和挂渣高度进行测量。实验结果表明：切缝宽度的大小主要由激光功率、切割速度、辅助气压力和离焦量决定；挂渣高度的大小主要决定于激光功率、切割速度、离焦量和辅助气压力。建立评价切缝宽度和挂渣高度与工艺参数之间的回归模型，并对模型进行目标优化。结果表明，工艺参数组合为激光功率450 W,切割速度9 m/min,离焦量0 mm,辅助气压力0.564 MPa时可获得最优的切割质量。     

光纤激光切割中厚铝合金板工艺特性研究

为了探究中厚板铝合金光纤激光切割工艺特性,开展了光纤激光切割8mm厚AA2219铝合金工艺实验,系统研究了激光功率、切割速度、离焦量和辅助气压等工艺参数对切缝质量的影响。以根部挂渣高度和切缝下部分倾斜条纹区域所占板厚比例来表征切缝质量。实验结果表明,激光功率和辅助气压是影响切缝质量的最主要的工艺参数,当激光功率增大至5.4kW、辅助气压取值范围增大至1100～1500kPa时,切缝挂渣量最少。最后,为了进一步提高中厚度铝合金激光切割质量,根据空气动力学原理,利用流体力学模拟设计并制作了简易Laval喷嘴,采用该喷嘴进行实验发现,切缝表面倾斜条纹区域范围从0.5降至0.14,而挂渣高度变化较小。     

精密齿轮光纤激光切割工艺研究

利用光纤激光精密加工系统进行了不锈钢齿轮的切割实验。研究了激光光斑直径及离焦量、切割速度、激光功率等工艺参数对齿轮切缝宽度及加工质量的影响。通过优化工艺参数,在0.4mm厚的不锈钢薄板上切割出了精密齿轮。     

铝锂合金光纤激光切割的工艺优化与设计

铝锂合金是航空航天工业中最理想的轻质高强结构材料,为提高铝锂合金切割质量,采用1 k W光纤激光器对2 mm铝锂合金进行切割试验。初步探讨了离焦量、辅助气体压力、激光功率和切割速度对切割质量的影响,深入研究了连续激光模式与脉冲激光模式下的切割质量差异,结果表明脉冲模式下切缝挂渣少、粗糙度小。在此基础上,通过正交试验直观分析、方差分析、信噪比分析对工艺参数进行优化设计,最终获得良好的切割质量:挂渣厚度为0.087 mm,表面粗糙度为4.81μm。     

激光精密切割不锈钢模板割缝质量控制

采用Nd∶YAG激光对 0 2mm厚的不锈钢模板精密切割 ,系统研究了激光切割工艺参数对缝壁表面粗糙度、缝壁表面残留物的影响规律 ,结果表明 :提高重复频率、功率密度、脉冲宽度以及降低扫描速度 ,均可改善切缝质量。导出了描述脉冲激光切割切缝表面粗糙度的公式 ,利用该公式可以较好地解释本文的实验结果。最后 ,提出了控制激光精密切割切缝缝壁质量的方法。     

光纤激光切割铝合金薄板工艺特性研究

为了探究光纤激光切割铝合金的工艺特性,开展了光纤激光切割2mm厚度AA6061铝合金工艺实验,系统研究了激光功率、切割速度、辅助气压等工艺参数对切割质量的影响规律。在优化工艺参数条件下可以获得根部挂渣小于0.1mm、切面粗糙度小于3μm,且拼合后无肉眼可见间隙的切缝。当激光功率为3.0kW时,光纤激光获得优质切缝的切割速度可达9m/min。结果表明,增大激光功率至3.0kW,提高切割速度至6m/min,升高喷嘴间距至0.5mm或增加辅助气压至1.1MPa后,挂渣量降至0.1mm以下,最小为20μm。当切缝表面粗糙度通常约为3μm,可得到的最小热影响区宽度为10μm。最后,基于线性回归法建立的数学模型,模型预测值和实测值吻合良好。     

脉冲光纤激光加工36MnVS4连杆裂解槽的研究

为了获得新材料36 MnVS4连杆裂解槽的最优切割质量,采用光纤激光器对36 MnVS4连杆进行了裂解槽激光加工的工艺研究,分析了离焦量、峰值功率、脉冲宽度、切割速度和脉冲频率对裂解槽几何尺寸的影响,通过激光共聚焦显微镜测量对比,研究不同激光工艺参数下裂解槽几何尺寸的变化规律。结果表明:负离焦能加工出质量更好的裂解槽;峰值功率、脉冲宽度、脉冲频率和切割速度对槽深和张角的影响较大,对槽宽和曲率半径的影响较小,但在裂解槽深度为0.5~0.6 mm时,张角在10°~25°的较小范围内变化。     

激光参量对血管支架切缝形貌及粗糙度的影响

为了研究激光加工工艺参量对血管支架切缝形貌以及表面粗糙度的影响，采用不同参量对比分析试验法，开展了心血管支架316L材料光纤激光切割实验，分析了激光脉冲宽度、激光功率和切割速率等不同工艺参量对材料切缝形貌及粗糙度的影响，得出激光切割支架的最佳工艺参量组合。结果表明，不同区域切缝形貌和表面粗糙度存在差异性，其中支架切缝的汽化区厚度主要受脉冲宽度及激光功率影响，当脉冲宽度为35μs时，支架切缝汽化区厚度最大可达到120μm；支架切缝汽化区粗糙度随切割速率增加先减小后增大，当切割速率为6mm/s时，切缝表面粗糙度值最低为650nm。此研究结果为心血管支架光纤加工的研究及后续光整加工奠定了理论基础。     

光纤激光切割碳钢的工艺研究

采用2kw光纤激光器对16mm以下Q235-A碳钢进行切割,以3mm及10mm为例进行工艺分析.在工艺优化后,对各样件进行分析.分析了焦点距离、激光功率、离焦量、气压各参数对切缝形貌,粗糙度、条纹的影响.结果表明,与传统的激光器不同,光纤激光切割3mm的碳钢一般为正离焦,切割10mm碳钢一般选择负离焦.切割薄板时,为了提高速度,一般选择高功率、高气压切割.切割厚板时,确保切面质量,一般选择高功率、低气压.     

激光精密切割不锈钢薄板的工艺研究

采用Nd∶YAG脉冲激光器对不锈钢进行了精密切割。系统研究了工艺参数对切缝宽度和切缝质量的影响规律。结果表明,缝宽随激光功率密度、频率以及脉宽的增加而加大;提高激光输出重复频率,不仅有利于提高加工质量,而且可以增大切割速度,提高加工效率。在此基础上,导出了光斑重叠度和极限切割速度的计算公式,利用此公式估算的脉冲激光切割的极限速度与实验结果符合很好     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.