双河泵站辐射井设计参数及经济效益

本文介绍了辐射井的井位布置方法和井身设计参数的确定。对给排水设计手册推荐的井壁出水量计算公式进行了一些修正。由作者设计并已竣工的泌阳化肥厂、南阳油田辐射井工程,出水量大、水质好造价低,是山区、丘陵区工业及农用泵站的良好取水方式之一,据河南石油勘探局水电厂的统计,在供水量均为1.6万立米/日的情况下,辐射井比原有的管井群可节约基建费29.7万元,节约年运行费35.3万元。     

Selective Triplet–Singlet Förster-Resonance Energy Transfer for Bright Red Afterglow Emission

Förster-resonance energy transfer (FRET_T-S) from the lowest excited triplet state (T₁) of a donating sensitizer to a fluorescence acceptor can be used to obtain bright room-temperature afterglow emission at long wavelengths. However, the energy transfer from the lowest excited singlet state of the donor to the acceptor is an undesirable deactivation pathway that prevents FRET_T-S. Herein, heteroatoms in chromophores are shown to allow selective and efficient FRET_T-S for enhanced triplet emission for bright room-temperature afterglow emission at long wavelengths. Different transition characteristics between the lowest singlet excited state and triplet states in heteroatom-containing chromophores accelerate triplet generation, enabling near-zero fluorescence yields. Out-of-plane vibrations of the heteroatoms in aromatic fused rings greatly enhance the radiative rate from T₁ by a factor of 88 relative to non-heteroatom-containing fused chromophore. The compatibility of the near-zero fluorescence and the enhanced triplet emission in a heteroatom-containing fused chromophore enable selective and efficient FRET_T-S pathways, resulting in room-temperature red afterglow emission with a yield of 17%. The bright emission at long-wavelengths allows distinguishable, multiple spectral signals in ambient white light.     

圆角特征识别研究

圆角特征识别是特征识别中的一个重要环节。圆角特征主要由圆柱面、球面、环面、B-spline曲面等组成,相互连接成链状或网状结构,据此文章提出了最小等半径连通图方法来识别圆角特征。首先将具有圆角特征表面特性的几何表面筛选出来,根据这些面的连接关系建立面边图。并在图中记录下面和连接边的半径,从而将圆角特征的识别转化为等半径连通子图的搜索。     

基于微水试验的北京大兴隐伏岩溶裂隙渗透系数求取方法研究

微水试验是进行岩土体渗透性测试的重要技术手段与方法。选取北京大兴隐伏奥陶系灰岩岩溶裂隙含水层作为目标层,依据现场条件选择生产井,利用水位自动监测装置记录停泵水位恢复法,HSZK振荡试验法与注水试验法进行微水试验应用研究,发现获得的目标层渗透系数小于传统抽水试验结果。分析认为造成这种差异的原因在于不同试验方法的影响半径不同,而微水试验结果更能体现试验点岩土体的渗透性。此外,在裂隙与岩溶介质中运用微水试验要尽量减小、避免皮肤效应的影响,选择试验方法时要保证水位瞬时变化的实现,对于主裂隙,可以借助栓塞进行分段试验。     

对铁饼大半径旋转技术动作的商榷

本文通过技术动作分析及结合个人经验,利用大半径旋转技术来提高铁饼运动成绩。     

A model to calibrate and predict forces in machining with honed cutting tools or inserts

This paper describes a mechanistic approach towards modeling the effects on machining forces of the edge hone commonly ground on machining tools and tool inserts. This approach proposes that the ratio of the shearing to ploughing forces would remain identical for tools with different honed radii, machining under identical conditions of chip thickness to edge hone radius ratios and cutting velocity. This concept allows a very simple and new calibration technique toward separating out the effects of tool and machining parameters that influence the force coefficients in machining without a need for any additional parameters. The model has been presently developed for orthogonal cutting and its validation using a tube turning process on gray cast iron with straight edged inserts has shown very promising results. Continued research is being performed to evaluate the applicability of the model for more complex machining operations.     

Stability radii of positive discrete-time systems under affine parameter perturbations

In this paper we study stability radii of positive linear discrete-time systems under affine parameter perturbations. It is shown that real and complex stability radii of positive systems coincide for arbitrary perturbation structures, in particular, for blockdiagonal disturbances as considered in μ-analysis. Estimates and computable formulae are derived for these stability radii. The results are derived for arbitrary perturbation norms induced by monotonic vector norms (e.g. p-norms, 1⩽p⩽∞). © 1998 John Wiley & Sons, Ltd.     

The asymptotic behavior of the stability radius for a singularly perturbed linear system

In this paper we study the asymptotic behavior of the stability radius of a singularly perturbed system when the small parameter ε tends to zero. It is proved that for such systems the stability radius tends to the min(r₁,r₂), where r₁ is the inverse of the H_∞-norm of the reduced slow model and r₂ is the stability radius of the boundary layer system. © 1998 John Wiley & Sons, Ltd.     

旋转闪蒸干燥机分级器半径、鼓风量及引风量的最佳匹配

在实验的基础上分别建立了分级器半径、鼓风量及引风量三者与干燥产品粒度和湿度的函数表达式,并采用复合形法对方程进行了优化,结果对干燥过程的操作具有一定指导作用     

Evaluation of space radius formed by blasting pressure with linear charges

Based on the mechanism analysis of space form caused by blasting with linear charges, elastic-plastic model of space form caused by blasting was established in this paper. In terms of state equation of blasting and the balance of quality, evaluation formula based on elastic-plastic to estimate space diameter caused by blasting with linear charges was given. The procedure structure of evaluation was introduced. We did 18 experiments on situ and compared experiments results with evaluation ones. They are correspondent very well. Then a new method of evaluating underground space diameters caused by blasting with linear charges was given. The method has more great guidance significance to the optimism plan of the new blasting technology that utilizes the explosion effect of the explosive to compact the soil to form the underground space.