基于GM（1，1）模型的某高校招生人数预测

分析了近年来我国高校招生人数的变化趋势，并利用GM（1，1）模型对某高校2008年的招生人数进行了预测．从而为高校招生人数决策提供了依据。     

多沙水源取水泵站正向前池边壁型式及圆形进水池尺寸的确定

通过理论分析、模型试验和对现有多沙水源取水工程的调查,研究并给出了正向前池边壁的合理曲线型式和圆形进水池尺寸的确定方法。研究结果可应用于实际工程。     

新型杀菌剂氟吗啉在黄瓜植株体内的吸收传导行为

利用生物测定技术和高效液相色谱法研究了氟吗啉在黄瓜植株体内的吸收、传导和分布行为及其机制. 结果表明, 氟吗啉能被黄瓜植株被动吸收, 并通过木质部在体内传导和分布.     

Analysis of acrylamide in coffee and dietary exposure to acrylamide from coffee

An analytical method for analysing acrylamide in coffee was validated. The analysis of prepared coffee includes a comprehensive clean-up using multimode solid-phase extraction (SPE) by automatic SPE equipment and detection by liquid chromatography tandem mass spectrometry using electrospray in the positive mode. The recoveries of acrylamide in ready-to-drink coffee spiked with 5 and 10 μg l⁻¹ were 96±14% and 100±8%, respectively. Within laboratory reproducibility for the same spiking levels were 14% and 9%, respectively. Coffee samples (n = 25) prepared twice by coffee machines and twice by a French Press Cafetière coffee maker contained 8±3 μg l⁻¹ and 9±3 μg l⁻¹ acrylamide. Five ready-to-drink instant coffee prepared twice contained 8±2 μg l⁻¹. Hence, the results do not show significant differences in the acrylamide contents in ready-to-drink coffee prepared by coffee machine, French Press or from instant coffee. Medium roasted coffee contained more acrylamide (10 μg l⁻¹) than dark roasted coffee (5 μg l⁻¹). Males aged 35–45 years, drinking on average 1.1 l coffee per day are exposed to the highest doses of acrylamide from coffee. The dietary intake of acrylamide from coffee comprises, on an average, 10 μg day⁻¹ for males and 9 μg day⁻¹ for females aged 35–45 years. Probabilistic modelling of the exposure of Danish consumers (all adults) to acrylamide from coffee shows a mean exposure of 6.5 μg day⁻¹ and a 95 percentile of 18 μg day⁻¹.     

准均质充量压燃发动机低负荷排放性能的试验研究

通过试验研究了引燃油量和进气节流对天然气／柴油双燃料准均质充量压燃(QHCCI)发动机低负荷排放性能的影响．结果表明：在低负荷时适当地增加引燃油量，不但可以降低QHCCI发动机的排放，又可以提高其热效率；适当采用进气节流，可在热效率略有降低的情况下有效地改善QHCCI发动机在低负荷时的排放性能；在增大引燃油量的同时采用一定程度的进气节流对降低QHCCI发动机低负荷排放更为有利．     

增压柴油机进气系统尺寸配合对性能的影响

本文根据增压四冲程柴油机进气特点，假定进气气流为一元不可压缩准稳定的流动，推导出用无因次参数表示的进气系统部件尺寸配合的简化数学模型。按此方法确定的进气系统尺寸可提高充气系数而改善柴油机的经济性，并且已经为６１６０Ａ型增压四冲程柴油机的试验所证实。     

用模式叠加法计算进气道雷达散射面积

基于导波模式理论，将进气道复杂终端分成若干个等效终端，提出了用模式叠加法计算飞机进气道的内部雷达散射面积，推导了部分典型等效终端的数学模型，通过计算结果与相关文献实验数据对比表明该方法基本可行。该方法的特点是极化散射矩阵和终端反射系数可分解后分别计算，便于叠加各种进气道构型和不断积累计算模型。     

废气再循环阿特金森汽油机经济性优化算法

基于一维整机模型在3 000r·min-1部分负荷工况下对Atkinson汽油机性能进行仿真分析.结果表明,在保持节气门位置、空燃比与点火提前角不变的情况下,随着废气再循环率提升或随着LIVC(late intake valve closing)增大,发动机的油耗均呈现增大趋势.为进一步优化Atkinson发动机燃油经济性,在节气门全开条件下搭建了GT-power与MATLAB联合仿真模型,通过改进的遗传算法,对废气再循环率、进气门晚关角、点火提前角、空燃比等参数进行优化迭代,并对历代种群进行了模糊聚类分析,得出了不同负荷工况点的油耗最优值及对应的控制参数.     

Viscous flow in a mixed compression intake

Numerical simulation of the flow in a two‐dimensional mixed compression intake is carried out by solving unsteady viscous compressible equations using a stabilized finite element method. The effect of bleed in starting/unstarting of the intake and controlling the buzz instability is investigated in detail. Higher bleed leads to an increase in the ability of the intake to sustain larger back‐pressure for stable operation. The amount of bleed and its location is varied to understand its effect on the performance of the intake. Two kinds of unsteady oscillations are observed: ‘little’ and ‘big’ buzz. The frequency of the both kinds of buzz oscillations is found to be super‐harmonic of the fundamental acoustic frequency of intake modeled as an open‐closed organ pipe. The frequency as well as amplitudes of the big buzz cycles is larger than those of the little buzz. The little‐ and big‐buzz are found to occur for low‐ and high‐subcritical state of the intake and are very similar to Ferri and Dailey criteria, respectively. Buzz is eliminated when relatively high bleed is implemented, both, upstream and downstream of the throat. The effect of rate of change of back‐pressure on the start/unstart of the intake is investigated. Two situations are considered. The first case is that of an intake where the back‐pressure remains below the critical value. It is found that the intake remains started if the change in back‐pressure is gradual. However, it unstarts if the back‐pressure is changed relatively rapidly. The second set of simulations is an attempt to model the situation where the back‐pressure at the exit of the intake exceeds the critical value and a logic is incorporated in the feed back loop of the fuel modulation to start the intake. Low rate of change of pressure is unsuccessful in starting the intake. Relatively high rates result in either a quick starting of the intake or a slow unstart. Copyright © 2010 John Wiley & Sons, Ltd.     

ON THE STRUCTURE OF STEADY FLOW THROUGH DUAL-INTAKE ENGINE PORTS

The influence of intake port design on the flow field in a dual-intake valve engine was investigated using computational fluid dynamics, in order to study the effect of inlet port design on the in-cylinder flow. A detailed 3D computational grid incorporating all the features of the Ford Zetec production engine inlet ports, valves and cylinder head was initially created and the flow structure modelled at 5 and 10 mm valve lifts under steady flow conditions. Comparisons of computational results with experimental data obtained by laser Doppler anemometry indicate that the flow characteristics have been predicted well in most regions. Flow generated by different intake port designs was also simulated by introducing air into the cylinder at different directions to the inlet valve axes and the effects of port deactivation, throttling and exhaust gas recirculation were examined. The implications of the results for intake port design are discussed.