预混火焰条件下生物柴油羰基物的生成与影响因素分析

羰基物是低温燃烧过程中产生的不完全氧化中间产物,主要产生在预混燃烧阶段。从化学反应动力学角度,分析了预混火焰条件下,燃油量、过量空气系数和调合比例等因素对生物柴油羰基物生成的影响。通过改变空气稀释比进行空气预处理,通过掺混氢气、掺混一氧化碳、掺混甲烷进行燃料预处理,对生物柴油羰基类污染物的排放控制进行了数值模拟。研究结...     

线性支出系统及其在我国的应用

研究我国城市居民家庭支出模式是有意义的。本文采用线性支出系统和广义线性支出系统,建立了我国城市居民家庭支出结构的数学模型。线性支出系统有助于人们搞清价格在家庭对各种商品支出份额配置上的作用和影响。根据线性支出系统和广义线性支出系统,我们求得价格弹性、交叉价格弹性和收入补偿价格弹性等。文章最后部分,我们对改善我国城市居民家庭支出结构提出一些建议。     

热致性液晶共聚酯的剪切流变行为

采用毛细管及锥板流变仪对ＰＥＴ／ＰＨＢ系液晶共聚酯ＬＣＰ８０的剪切流变行为进行了系统的研究，发现在较低剪切速率下ＬＣＰ８０即出现剪切烯化现象，因此在通常的加要剪切速率范围下粘度非常低；当温度大于３００℃后粘流活化能减小，粘度的温度依赖性明显减弱；由于过冷现象热史影响其流动曲线，并且经预剪切后粘度显著下降；在较低剪切速率下第一法向应力差出现负值，并开始表现出明显的弹性效应。     

Broad-band phase retrieval method for transient radial shearing interference using chirp Z transform technique

The transient radial shearing interferometry technique based on fast Fourier transform (FFT) provides a means for the measurement of the wavefront phase of transient light field. However, which factors affect the spatial bandwidth of the wavefront phase measurement of this technology and how to achieve high-precision measurement of the broad-band transient wavefront phase are problems that need to be studied further. To this end, a theoretical model of phase-retrieved bandwidth of radial shearing interferometry is established in this paper. The influence of the spatial carrier frequency and the calculation window on phase-retrieved bandwidth is analyzed, and the optimal carrier frequency and calculation window are obtained. On this basis, a broad-band transient radial shearing interference phase-retrieval method based on chirp Z transform (CZT) is proposed, and the corresponding algorithm is given. Through theoretical simulation, a known phase is used to generate the interferogram and it is retrieved by the traditional method and the proposed method respectively. The residual wavefront RMS of the traditional method is 0.146λ, and it is 0.037λ for the proposed method, which manifests an improvement of accuracy by an order of magnitude. At the same time, different levels of signal-to-noise ratios (SNRs) from 50 dB to 10 dB of the interferogram are simulated, and the RMS of the residual wavefront is from 0.040λ to 0.066λ. In terms of experiments, an experimental verification device based on a phase-only spatial light modulator is built, and the known phase on the modulator is retrieved from the actual interferogram. The RMS of the residual wavefront retrieved through FFT is 0.112λ, and it decreases to 0.035λ through CZT. The experimental results verify the effectiveness of the method proposed in this paper. Furthermore, the method can be used in other types of spatial carrier frequency interference, such as lateral shearing interference, rotational shearing interference, flipping shearing interference, and four-wave shearing interference.     

基于"产学研用"背景下的仪器分析课程教学机制研究

"产学研用"是高等教育实现人才培养目标的重要途径。本文在"产学研用"教学一体化背景下,为提高仪器分析课程教学效果,强化课程对学生专业能力、科研能力和解决企业实际问题的能力培养,在分析目前课程教学存在问题的基础上,对仪器分析"产学研用"教学机制、教学方法、资源共享平台建设、教学团队建设、教学考核等问题进行一体化建设探索,以期通过"产学研用"教学建设促进人才培养质量进一步提升,并对高校培养人才与企业实际需求人才的有效衔接问题提供一定的解决思路。