合成氨工艺参数优化技术开发及应用

以氨净值为响应值,影响响应值的17个过程参数为变量,经逐步回归选入触媒温度左3,触媒温度左4,循环CH_4%,H/N,NH_3%(进口)5个过程参数建立预测方程,并根据该方程对响应值的拟合结果和误差分布对样本进行分类。在此基础上,采取图形显示技术和统计分析的方法对分类样本集的过程参数进行比对分析,由此获取优类信息制订优化的工艺参数方案,经仿真验证后用于指导合成氨装置的生产试验。试验结果与试验前的对照期比较,氨净值均值由13.86提高到14.54,吨氨气耗减少15.9887m~3,吨氨电耗减少15.8kWh,节能效益十分明显     

一种中文文档的非受限无词典抽词方法

本文提出了一种非受限无词典抽词模型,该模型通过自增长算法获取中文文档中的汉字结合模式,并引入支持度、置信度等概念来筛选词条。实验表明:在无需词典支持和利用语料库学习的前提下,该算法能够快速、准确地抽取中文文档中的中、高频词条。适于对词条频度敏感,而又对计算速度要求很高的中文信息处理应用,例如实时文档自动分类系统。     

工业设计专业基础设计教学思考与探索

基础设计课程是工业设计专业从基础课程过渡到产品设计课程之间的桥梁,采用理论与实践相结合以实践教学为主的教学方法,理论环节以实例讲授为主,实践环节主要是专题设计训练,培养学生的观察、感受和把握的能力,着重于从纯粹的无目的的形态构成到实际产品设计的过渡,系统地训练产品设计的创意思维方法。在学习过程中运用基础课程的原理与方法,通过手工制作出有实用功能、形式美感兼备的产品雏形。     

利用SHELL编程实现UNIX系统下气象资料传输与处理

本文对UNIX环境下SHELL脚本语言进行了简要介绍,并举例说明了如何利用SHELL脚本语言实现UNIX/Linux系统下气象资料传输与处理。     

Visualizing multiwavelength astrophysical data

With recent advances in the measurement technology for allsky astrophysical imaging, our view of the sky is no longer limited to the tiny visible spectral range over the 2D Celestial sphere. We now can access a third dimension corresponding to a broad electromagnetic spectrum with a wide range of allsky surveys; these surveys span frequency bands including long wavelength radio, microwaves, very short X-rays, and gamma rays. These advances motivate us to study and examine multiwavelength visualization techniques to maximize our capabilities to visualize and exploit these informative image data sets. In this work, we begin with the processing of the data themselves, uniformizing the representations and units of raw data obtained from varied detector sources. Then we apply tools to map, convert, color-code, and format the multiwavelength data in forms useful for applications. We explore different visual representations for displaying the data, including such methods as textured image stacks, the horseshoe representation, and GPU-based volume visualization. A family of visual tools and analysis methods is introduced to explore the data, including interactive data mapping on the graphics processing unit (GPU), the mini-map explorer, and GPU-based interactive feature analysis.     

On the convergence rate of ordinal comparisons of random variables

The asymptotic exponential convergence rate of ordinal comparisons follows from well-known results in large deviations theory, where the critical condition is the existence of a finite moment generating function. In this note, we show that this is both a necessary and sufficient condition, and also show how one can recover the exponential convergence rate in cases where the moment generating function is not finite. In particular, by working with appropriately truncated versions of the original random variables, the exponential convergence rate can be recovered     

~(123)I的制备及其快速标记

本文报道了在原子能研究所1.2米回旋加速器上用26MeV的α粒子流轰击天然丰度的锑靶,通过~(121)Sb(α,2n)~(123)I反应,以铜基铂吸附剂对碘选择性吸附法分离和浓集~(123)I,制得Na~(123)I溶液。Na~(123)I的放化纯度大于99％。在辐照结束时,其主要放射性杂质~(124)I占产品~(123)I的比率小于1.4％,整个分离过程不到4小时即可完成,总的化学收率在95％以上。所得产品用冠醚为溶剂,对肾上腺显影剂6-碘甲基-19-去甲胆固醇以及心脏显影剂ω-~(123)I-十七烷酸进行了快速标记。结果表明,与国内外现用的标记方法相比较,该法具有快速、简便、产额高等优点。     

The aeroelastic effects on the scatter phenomenon of wind-tunnel data

The unsteady Reynolds-averaged Navier-Stokes equations coupled with the k SST turbulence model are solved to obtain the steady and unsteady aerodynamic forces for airfoils and wings.The effects of vibration types and amplitudes on aerodynamic forces of airfoils and wings are studied.The deformation characteristics of a swept wing induced by steady aerodynamic load are presented.It is found that for a vibrating elastic wing at small and medium incidences,its mean aerodynamic loads are almost the same as those obtained from the static one.On the contrary,at high incidences especially around the stall incidence,the vibration may change the mean values.In addition,the larger amplitude is,the larger discrepancy will be.For a swept wing,the steady aerodynamic loads usually lead to the "pitching down" effect on the wing tip which delays the stall compared with a rigid one;But this phenomenon dose not occur on a aeroelastic wing which can induce the separation ahead and trigger the stall.The above conclusions are in good agreement with the scatter characteristics of wind-tunnel data.The reason why the data obtained from wind tunnel and CFD are different is also analyzed.Meanwhile,it can be an explanation for scatter phenomenon of wind-tunnel data,especially for high incidence cases,which remains a puzzle so far.     

Experimental study of hypervapotron under conditions of high heat flux

In the light of the needs to develop high-performance heat transfer component for nation-level large-scale scientific projects of China,a hypervapotron experimental platform with supply of heat flux 1 10 MW m-2 was established.With this platform,the multiphase flow and heat transfer phenomena on the surface of triangular fin when the subcooled water flowed through were observed and measured with the planar laser induced fluorescence(PLIF) and high-speed photography techniques.The temperature contour on the slice plane of fin symmetry was measured and the heat flux contour was processed based on gradient computation.It is confirmed that:1) PLIF with high-speed photography is very powerful technique to investigate the multiphase flow of hypervapotron quantitatively;2) evaporation is the primary way in heat transfer mechanism of hypervapotron flow under the condition of high heat flux.The techniques and results obtained will provide useful reference in the R&D of hypervapotron technology in China.     

一类Holling Ⅲ型Leslie-Gower模型的持久性与灭绝性

讨论了一类食饵具有Holling Ⅲ功能反应的Leslie-Gower模型的动力学行为,应用脉冲微分方程的比较原理及其现代分析方法,得到了系统灭绝和永久持久性的阈值条件,推广了只有一次脉冲和没有功能性反应时的情形.