基于宏观断面的内饰B面设计

在汽车造型设计中,确保设计师的造型思想能够在工程上得以实现,始终是贯穿在造型设计中的一条主线。本文重点阐述了在B面设计阶段,如何基于宏观断面输入,使得最终发布的B面数据既符合造型要求,又满足各种工程约束的方法及流程。     

基于脉搏光谱分形算法的血氧测量研究

脉搏光谱测量方法被普遍用于临床的血氧饱和度的监测,由于检测时低血氧和血氧波动将改变血红蛋白的吸光系数,会造成脉搏光谱测量的误差。本文针对血氧波动、外界环境等产生的噪声干扰问题,采用脉搏光谱分形法去除光谱信号中的噪声干扰,利用自适应校正后的准理想光谱计算血氧饱和度,使得血氧饱和度的值更为精确,从而进一步保证其他生理参数的准确计算。实验结果表明,该方法有效提高了血氧饱和度的检测精度,为抗血氧干扰的无创肝储备功能的检测提供理论依据和实用方法。     

可再分散乳胶粉对泡沫混凝土的改性作用

针对普通泡沫混凝土受环境变化及自身因素影响容易开裂的问题,通过加入可再分散乳胶粉,改善材料的抗裂性能.结果表明,可再分散乳胶粉、聚丙烯纤维、纤维素醚等外加剂的复掺,可以提高泡沫混凝土的柔韧性和抗冲击性能。     

梯形不锈钢筛条堆拉系数数学模型的优化

为提高连轧过程堆拉状态的控制精度,提出填充系数对堆拉系数的影响关系,得到改进后的堆拉系数模型。借助ANSYSLS-DYNA有限元软件,建立4道次梯形不锈钢筛条的轧制三维有限元模型并进行仿真,获得轧制过程轧件填充系数、前滑系数、堆拉系数等参数。与传统堆拉系数数学模型计算结果相比,改进后的堆拉系数数学模型更能真实反映连轧过程堆拉状态。     

控水压裂工艺方法及效果分析

针对不同储层的渗流特征以及压裂裂缝扩展规律,探讨油井控水压裂技术实施效果。分别通过选择性控水支撑剂、透油阻水压裂液、人工隔离层等工艺进行现场先导实验,观察分析控水工艺使用前后含水率与产油量的情况。根据不同高含水井区的工程地质特征,提出控水压裂工艺优化选择方案。     

考虑供水系统深度响应的微网经济调度策略

高风电渗透率微网(microgrid,MG)存在实时功率平衡和经济运行难的问题。为此,该文提出一种考虑供水系统(water supply system,WSS)深度响应的MG经济调度策略。首先,将WSS主动解列成多个独立运行的子系统,降低系统关联约束,提高调节灵活性。进而,建立水压的波动性约束,提出WSS需求侧响应模型。在此基础上,充分考虑外电网调峰、调频等需求,提出一种新型的MG经济调度策略。最后,引入近似线性化的方法,将非线性模型转化为经典的混合整数线性规划(mixed-integerlinearprogramming,MILP)问题,提高求解速度。基于15节点的WSS和典型MG的仿真结果表明,WSS深度响应能够显著改善MG运行经济性。该文研究成果为MG可再生能源消纳问题的解决提供了一个崭新的视角。     

冷柱头进样气相色谱法分析橡胶防护蜡的碳数分布

研究冷柱头进样气相色谱法分析橡胶防护蜡的碳数分布以及正构烷烃/非正构烷烃比例。结果表明,采用冷柱头进样方法,在样品量为10 mg、样品完全溶解后静置10~30 min并取上层清液以及进样量为1μL时,分析得到的气相色谱峰的峰形和响应信号最优。本方法测定橡胶防护蜡的碳数分布以及正构烷烃/非正构烷烃比例结果准确、可靠。     

HEAT TREATMENT STRENGTHENING EFFECTS OF RARE EARTHS ON Mg—9Al ALLOY

Mg-9Al-xRE magnesium alloys were studied, where, x is 0, 0.4. 0.8. 1.2 and 1.6% (in weight percent, wt%), respectively. Influence of rare earths (RE) on microstructure and strength in both T4 (solute heat treatment) and T6 (solute heat treatment and artificial ageing treatment) were investigated. Strength of specimen was tested at ambient temperature. The micro structure was analyzed by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction analysis. RE additions improved T4 tensile strength of the treated alloys. Small addition (0.4wt%) of RE greatly improved the strength of ageing treated (T6) Mg-9Al alloy, but further additions caused decreasing.     

Si复合Al2O3-SiC材料热机械性能的研究

通过应力-应变关系、高温抗折强度等高温试验，研究了金属硅复合Al2O3-SiC材料的热机械性能，结合SEM和XRD，对金属硅复合Al2O3-SiC材料高温显微结构和物相进行分析。结果表明：金属硅作为一个组元，不仅能缓解Al2O3-SiC材料由于热膨胀系数不匹配产生的内应力，而且使Al2O3-SiC材料兼具有金属塑性的特点，从而改善了Al2O3-SiC无机材料热机械性能。     

Adaptive interpolation scheme for NURBS curves with the integration of machining dynamics

This paper develops a comprehensive interpolation scheme for non-uniform rational B-spline (NURBS) curves, which does not only simultaneously meet the requirements of both constant feedrate and chord accuracy, but also real-time integrates machining dynamics in the interpolation stage. Although the existing work in this regard has realized the importance to simultaneously consider chord error and machining dynamics, none has really incorporated these in one complete interpolation scheme. In this paper, machining dynamics is considered for three aspects: sharp corners or feedrate sensitive corners on the curves, components with high frequencies or frequencies matching machine natural ones and high jerks. A look-ahead module was developed for detecting and adaptively adjusting the feedrate at the sharp corners. By Fast Fourier Transform (FFT) analysis with a moving window in the interpolation stage identified were some special frequency components such as those containing high frequencies or with frequencies matching machine natural ones. Then, the notch filtering or time spacing method was used to eliminate these components. To more completely reduce feedrate and acceleration fluctuations, the jerk-limited algorithm was also developed. Finally, the interpolated feedrate was further smoothened with B-spline fitting method and the NURBS curves were re-interpolated with the smoothened feedrate. During the interpolation, the chord error was repeatedly checked and confined in the prescribed tolerance. Two NURBS curves were used as examples to test the feasibility of the developed interpolation scheme.