共查询到20条相似文献，搜索用时 140 毫秒
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当前高精度的光波导微模具飞切加工工艺相当烦琐,光学元器件的微模具结构已经全面进入应用阶段。在这样条件下,提出了光波导微模具飞切加工工艺的方法。高精度飞切加工工艺系统的模具材料是用硬铝来进行正交试验的。试验表明:对光波导微模具结构影响最大的是背吃刀量,主轴的旋转速率对微模具结构的影响也很大,进给量所给的影响就稍小了。再根据机床运作的稳定性和工作效率,最后确定了光波导微模具飞切加工工艺最适合的参数。这些参数为:背吃刀量为25微米,主轴的转动速率为每分钟800转,进给量为每分钟20毫米。然后再对工艺参数进行优化,最终确定微模具结构表面粗糙度是17.1纳米的波导微模具。 相似文献
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光切法显微镜是以光切法为测量原理，测量表面粗糙度的专用光学仪器之一。文章主要就光切法显微镜物镜放大倍数确定问题加以阐述，解决了显微镜的使用问题。 相似文献
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最值问题是中学数学的重点和难点内容之一,确定正确的解题方向是解题成功的关键 .本文介绍十一种最值问题的思维发散方向 . 一、联想二次函数 例 1. 求函数 y=x2－的最小值 . 解：令 u= (u≥ ),有 x2=. y=u2－ u－ =(u－ 1)2－ 2, 由根据二次 函数的性质可得 ymin=－ . 二、联想函数的单调性 例 2.求函数 y=(a2>b2)的最小值 . 解：令 u= (u≥ |a|),则 y=u＋ (u≥ |a|). 易证函数 y=u＋ (u≥ |a|)为增函数 . ∴ 当 u=|a|,即 x=0时,函数有最小值为 . 三、联想正弦型或余弦型函数的有界性 例 3. 求函数 y=x＋的最值 . 解：令 x=sinα,α∈… 相似文献
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王亚元 《实验室研究与探索》2004,23(6):47-48
表面粗糙度是机械零件表面质量的重要组成部分。表面粗糙度的大小影响着机械零件的耐磨性、机械强度、抗腐蚀性及配合的稳定性，直接影响着机器的工作精度及寿命。因此对机械零件表面粗糙度的测量、评定就显得尤为重要。 相似文献
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华沛 《赤峰学院学报(自然科学版)》2014,(5):6-7
本文主要通过对复杂接触表面问题、流固耦合方程组以及边界条件切触不确定性的分析详细探讨了复杂表面问题的有限元计算的问题,希望能够对我国科研测试中的碰撞安全测试的最优接触问题的计算方法的研究有所帮助. 相似文献
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华沛 《赤峰学院学报(自然科学版)》2014,(8):5-6
本文通过对复杂接触表面问题、流固耦合方程组以及边界条件切触不确定性的分析详细探讨了复杂表面问题的有限元计算与分析,希望能够为碰撞安全测试中最优接触问题的计算方法研究提供帮助. 相似文献
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新型阳离子和两性皮革加脂剂的制备与性能 总被引：2，自引：0，他引：2
周春生 《商洛师范专科学校学报》2002,16(3):79-80
分别用两种新型表面活性剂配置了两种新型皮革加脂剂，并测定了其理化性质，将其用于山羊服装革的加脂，可使粒面丰满、柔软、有弹性，具有良好的加脂效果． 相似文献
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It is a challenge for passive RFID tags to be mounted on the surface of metal because the parameters of tag antennas, such as the impedance matching, the radiation efficiency and the radiation pattern, are seriously affected by the metallic surface. This paper presents the characteristics of the dipole-like antennas of ultra high frequency （UHF） radio frequency identification （RFID） tags that are placed close to metallic surfaces. The finite element method （FEM） and method of moment （MoM） were used to simulate the changes of the antenna parameters near the metallic surface. Two typical dipole-like antennas close to the metallic surface, a closed loop antenna and a loaded meander antenna, were modeled, and the performance was evaluated. Experiment was carried out and the results were in good agreement with the simulation, showing that a distance of 0.05λ-0.1λ （λ is the free space wavelength） from the metallic surface could make the dipole-like UHF RFID tag performance be acceptable. 相似文献
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This paper makes an approach to the approximate optimum in structural design, which combines the global response surface (GRS)
based multivariate adaptive regression splines (MARS) with Move-Limit strategy (MLS). MARS is an adaptive regression process,
which fits in with the multidimensional problems. It adopts a modified recursive partitioning strategy to simplify high-dimensional
problems into smaller highly accurate models. MLS for moving and resizing the search sub-regions is employed in the space
of design variables. The quality of the approximation functions and the convergence history of the optimization process are
reflected in MLS. The disadvantages of the conventional response surface method (RSM) have been avoided, specifically, highly
nonlinear high-dimensional problems. The GRS/MARS with MLS is applied to a high-dimensional test function and an engineering
problem to demonstrate its feasibility and convergence, and compared with quadratic response surface (QRS) models in terms
of computational efficiency and accuracy. 相似文献
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<正>The space-charge layer(SCL)and surface depletion area(SDA)model for beveled p-n junction is presented.The surface space-charge density is calculated for depletion case of beveled p-n junction.Based on the finite difference method, the effect of the equivalent surface charge density on the surface depletion area for positively beveled p-n junction is also studied.Thyristors passivated with polyimide(PI)or polyester improved silicon paint(SP)are fabricated to verify the effect of equivalent surface charge on the peripheral surface of beveled p-n junction.The change of leakage current is sensitive to the surface charges.It indicates that the selection of passivation materials is a significant process to ensure the breakdown voltage capability of beveled devices. 相似文献
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由原子转移自由基聚合（ATRP）和端基取代两步法制备得到了端基官能团聚合物（PS-NH-SO3Na）,对其结构进行了表征和动力学研究;又分别对PS-NH-SO3Na和一步ATRP法制备得到的端基官能团聚合物（PS-SO3Na）与表面阳离子化SiO2组装后粉体的残余质量进行了对比。动力学研究结果表明,当单体转化率控制在85%以内可得到高含量的活性端基聚合物;组装粉体的残余质量分析表明,ATRP聚合得到的聚合物存在一定量的死聚物。 相似文献
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S_(3307)和PP_(333)对龙眼实生苗生长发育和抗寒力的影响 总被引：2，自引：0，他引：2
本试验研究了两种三唑类植物生长延缓剂S_(3307)和PP_(333)对龙眼实生苗生长发育和抗寒力的影响,结果表明:1mg/L的S_(3307)和10mg/L的PP_(333)浸种、浸根均能促进幼苗根系的生长,显著提高根冠比,幼苗断根移栽时,S_(3307)和PP_(333)均能促进主根断口处萌发侧根,使幼苗迅速恢复生长发育,在低浓度下,S_(3307)的“控上促下”活性明显大于PP_(333),高浓度(S_(3307)>50mg/L,PP_(333)>100mg/L)会严重抑制幼苗生长,适宜浓度的S_(3307)和PP_(333)不仅可以加快龙眼砧木育苗速度,而且能明显提高幼苗对低温的抵抗能力。 相似文献
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Regression-Based Artificial Neural Network Methodology In Response Surface Methodology 总被引：3，自引：0，他引：3
Response surface methodology (RSM) is an important tool for process parameter optimization, robust design and other quality improvement efforts. When the relationship between influential input variables and output response is very complex, it‘ s hard to find the real response surface using RSM. In recent years artificial neural network (ANN) has been used in RSM. But the classical ANN does not work well under the constraints of real applications. An algorithm of regression-based ANN(R-ANN) is proposed in this paper, which is a supplement to the classical ANN methodology. It makes network closer to the response surface, so that training time is reduced and robustness is strengthened. The procedure of improving ANN by regressions is described and the comparisons among R-ANN, RSM and classical ANN are computed graphically in three examples. Our research shows that the R-ANN methodology is a good supplement to the RSM and classical ANN methodology, which can yield lower standard error of prediction under conditions that the scope of experiment is rigidly restricted. 相似文献
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In this study, the surface chemical properties of carbon nanotubes （CNTs） and carbon nanofibers （CNFs） grown by catalytic decomposition of methane on nickel and cobalt based catalysts were studied by DRIFT （Diffuse Reflectance Infrared Fourier Transform） and transmission Infrared （IR） spectroscopy. The results show that the surface exists not only carbon-hydrogen groups, but also carboxyl, ketene or quinone （carbonyl） oxygen-containing groups. These functional groups were formed in the process of the material growth, which result in large amount of chemical defect sites on the walls. 相似文献
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The effects of particle size of activated carbon （AC） on its wettability, electrode coating technology and electric chemical performance were studied to assemble nonaqueous electric double layer capacitors （EDLCs） for high power requirements. The results show that the specific surface area and total pore volume of AC decrease from 2 137 m^2/g to 1 683 m^2/g, and 0.95 cm^3/g to 0.78 cm^3/g, respectively, if it is ball-milled for 8 h. The pore size distributions are similar in the range of 0.7 nm to 3.5 nm for different ball-milling time. There exists oxidation on the surface of AC during the ball-milling process and the ratios of O-C=O oxygen compositions increase whereas those of C-O, C=O decrease. The peeling strength of AC coated on current collector is almost inverse proportion with the particle size of AC as well as the resistance of EDLCs, and its capacitance decreases about 6%. 相似文献
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表面粗糙度对摩擦影响机理的研究 总被引：1，自引：0，他引：1
陈容 《岳阳职业技术学院学报》2006,21(1):74-76
本文分析了表面粗糙度对摩擦的影响机理。结果表明:(1)聚合物试验中,在达到稳定摩擦值后,这一现象导致摩擦对表面粗糙度不敏感;(2)金属摩擦实验中,存在一最佳表面粗糙度级别,在此级别下,摩擦副的边界摩擦系数最小,耐磨性最好。 相似文献