木薯乙醇发酵过程中2步法通气策略的研究

文章用木薯为原料,以酿酒活性干酵母FY—05为出发菌株,进行发酵中,采用了不同的通气策略,研究对菌体生长以及乙醇产生量的影响,优先出最佳的通气策略运用于乙醇的发酵生产。结出了实验结果。     

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。     

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。     

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.     

An Advanced Oscillation Mixing Method for Improving the Cooling Uniformity in Quenching

In quenching, the cooling uniformity is most important to diminish distortion occurring on work pieces. As a trial to accomplish uniform cooling, therefore, there exist various mixing methods of a quenchant and the quenchant circulation with an external pump has so far been the well accepted mixing method. However, this study proposes an advanced oscillation mixing method that can improve more the cooling uniformity in quenching. The proposed method includes a stirrer in oscillating motion, so that the simultaneous oscillating and mixing movements of the stirrer are considered to provide efecfively the uniform cooling characteristics for the quenchant. In comparison with the case of the circulation pump mixing, the investigation using the oscillation mixing method has demonstrated the following two experimental facts:(1) the short vapor blanket stage caused by the quick breakage of the oil vapor blanket and (2) the reduced variation of the quenching distortion.     

板坯连铸二冷计算机仿真的研究和应用

连铸二冷计算机仿真是准确、迅速预测和分析工艺参数对浇注过程的影响规律以及优化连铸操作工艺参数的重要手段。基于沿拉坯方向上移动的有限薄片层思想,建立板坯连铸凝固传热数学模型,应用面向对象的编程语言Visual Basic 6.0开发了板坯连铸二冷计算机仿真软件,并针对国内某板坯连铸机应用仿真软件对其进行凝固过程模拟、对其二冷凝固过程进行工艺优化。应用红外线测温仪对板坯表面温度进行测试,测试温度与仿真结果吻合较好,说明连铸计算机仿真软件的计算是可靠的。     

中国硬质合金产业的技术进步

简要介绍了中国硬质合金产业技术进步的历程,阐述了在超细硬质合金、涂层硬质合金、CAD/CAM技术、喷雾干燥和气压烧结方面取得的长足进步。指出了中国硬质合金产业与国外先进水平的四大差距,提出了组建国家硬质合金工程研究中心,加强宏观调控,快速提升应用技术水平和培育高水平人才等重要对策。