高精度非线性格式WCNS的分析研究与其应用

首先将Fourier方法推广于高维方向研究了五阶精度WCNS的特性,并与其他高阶格式进行比较。分析结果表明WCNS的高精度特性普遍接近甚至好于迎风偏置五阶显式格式EUW-5与Pade′标准格式。然后开展了WCNS的应用研究,采用高效率的WCNS-E-5数值模拟了含强激波的高维复杂流场。算例包括二维高超声速边界层对自由流扰动波的吸收问题以及三维球头绕流问题。计算结果反映出WCNS-E-5对激波等间断的良好捕捉能力,图像清晰光滑,数据准确可靠。     

涡扇发动机旋转声模态发生与测试试验研究

开展了涡扇发动机旋转声模态发生与测试技术研究。首先,通过对涡扇发动机旋转声模态发生与测试技术的原理分析,得出声模态发生与测试试验装置设计方法;结构设计与电气系统设计相结合,完成了试验装置的搭建;最后经过以某高阶声模态为例进行试验验证工作,证明了声模态发生与测试技术的正确性和试验装置设计的合理性。开展的声模态发生与测试技术研究对消声短舱声衬的声学效果验证试验意义重大,填补了中国该工程领域的空白,具有较好的工程应用价值。     

Analysis and Discussion of Fiber Motion in the Spinning Triangle of Ring Spinning

In order to analyze the effect of the spinning triangle on yarn structure,a shape model of the spinning triangle is established.The fiber motion in the spinning triangle can be divided into three stages,and the relationship between yarn structure and fiber duration as well as the force acting on the fibers in the three stages is analyzed.The fiber elongation in different location of the spinning triangle is variational.The difference is that the elongation of fiber in the middle spinning triangle is bigger than that in the edge of it and the difference will be amplified with the increase of spinning triangle width,which has an effect on the characteristic of yarns structure.Research results for further study on compact yarn structure and improving spinning frame structure provide theorybasis.     

Additional Twists of Yarn Produced by System of Compact Spinning with Lattice Apron

Based on the flow simulation in the condensing zone of compact spinning with lattice apron and a bead-elastic rod dynamic model of the flexible fiber,trajectories of fibers with different negative pres...     

Utilizations of Statistics on Optimizing Parameters in Compact Spinning with Pneumatic Groove

The compact spinning with pneumatic groove utilizes transverse air force and mechanical force of the pneumatic groove to condense fiber bundles to eliminate the spinning triangle.Range analysis and var...     

On‐Line Monitoring of Chemical Reactions by using Bench‐Top Nuclear Magnetic Resonance Spectroscopy

Real‐time nuclear magnetic resonance (NMR) spectroscopy measurements carried out with a bench‐top system installed next to the reactor inside the fume hood of the chemistry laboratory are presented. To test the system for on‐line monitoring, a transfer hydrogenation reaction was studied by continuously pumping the reaction mixture from the reactor to the magnet and back in a closed loop. In addition to improving the time resolution provided by standard sampling methods, the use of such a flow setup eliminates the need for sample preparation. Owing to the progress in terms of field homogeneity and sensitivity now available with compact NMR spectrometers, small molecules dissolved at concentrations on the order of 1 mmol L^?1 can be characterized in single‐scan measurements with 1 Hz resolution. Owing to the reduced field strength of compact low‐field systems compared to that of conventional high‐field magnets, the overlap in the spectrum of different NMR signals is a typical situation. The data processing required to obtain concentrations in the presence of signal overlap are discussed in detail, methods such as plain integration and line‐fitting approaches are compared, and the accuracy of each method is determined. The kinetic rates measured for different catalytic concentrations show good agreement with those obtained with gas chromatography as a reference analytical method. Finally, as the measurements are performed under continuous flow conditions, the experimental setup and the flow parameters are optimized to maximize time resolution and signal‐to‐noise ratio.     

Sensing the Anti-Epileptic Drug Perampanel with Paper-Based Spinning SERS Substrates

The applications of SERS in therapeutic drug monitoring, or other fields of analytical chemistry, require the availability of sensitive sensors and experimental approaches that can be implemented in affordable ways. In this contribution, we show the production of cost-effective SERS sensors obtained by depositing Lee-Meisel Ag colloids on filter paper either by natural sedimentation or centrifugation. We have characterized the morphological and plasmonic features of the sensors by optical microscopy, SEM, and UV-Vis spectroscopy. Such sensors can be used to quantify by SERS the anti-epileptic drug Perampanel (in the concentration range 1 × 10⁻⁴–5 × 10⁻⁶ M) by spinning them during the micro-Raman measurements on the top of a custom device obtained from spare part hard disk drives. This approach minimizes laser-induced heating effects and allows averaging over the spatial non-uniformity of the sensor.     

关于代数L-domain的一个刻画定理

引入了强core紧拓扑空间的概念,给出了代数L-domain的刻画定理,其主要结果是:偏序集D是代数L-domain当且仅当对每个强core紧拓扑空间X,函数空间[X→D]是代数L-domain.     

解非定常不可压缩N-S方程的迭代压力Poisson方程法

１．引 言 数值求解不可压缩流体流动问题可以采用原始变量的方程作为控制方程,也可以用涡量一流函数方程作为控制方程．直接求解原始变量的不可压缩 Ｎａｖｉｅｒ—Ｓｔｏｋｅｓ方程存在一个主要困难：速度向量在每一时刻都必须满足零散度约束条件,即不可压缩性连续方程．用涡量一流函数方程求解时,连续方程自动满足,所以不存在约束条件的问题,但涡量的边界条件比较难处理,且不易应用于三维问题和带有自由表面或其它流体交界面的问题． 解决上述速度向量必须满足零散度约束条件的困难的方法有：人工压缩法［３,１７］;压力Ｐｏｉｓ…