竹醋液烟熏气化学成分的研究

采用固相微萃取(SPME)吸附采集竹醋液烟熏气的成分,用气相色谱—质谱联用分析鉴定,并用GC/MS总离子流色谱峰的峰面积进行归一化定量分析竹醋液烟熏气成分,鉴定出愈创木酚11.36%、苯酚10.6%、4-乙基苯酚8.23%、2-甲氧基-4-甲基苯酚7.08%、4-乙基-2-甲氧基苯酚6.6%、2-乙基苯酚5.65%、糠醛5.51%、5-甲基糖醛1.47%、乙酸1.42%、3-甲基-1-戊烯-3-醇1.42%、2,3-二甲基甲苯1.35%、2-糠酸甲酯1.35%、苯甲酸甲酯1.11%、2-甲基-2-环戊烯-1-酮1.44%、2,3-二甲基-2-环戊烯-1-酮1.31%、2-环戊烯-1-酮1.02%等74种化合物。竹醋液烟熏气的所有成分是竹醋液化学成分的特征性组成部分。     

低浓度SO2对油桐叶片细胞膜脂肪酸含量的影响

膜系统是细胞内光合和呼吸等生理活动的重要场所之一,SO2对光合系统的破坏首先会引起细胞膜系统的变化.气相色谱测定表明,体积分数为0.3×10-6的SO2对油桐叶片处理10d以上,会使不饱和脂肪酸含量UFA、不饱和脂肪酸指数IUFA、C18:3、C18:3/IUFA上升,使饱和脂肪酸含量、C16:1trans、C16:1trans/IUFA下降;但随着SO2熏气时间的延长,会使不饱和脂肪酸含量UFA、不饱和脂肪指数IUFA、C18:3、C18:3/IUFA下降,饱和脂肪酸含量上升,熏气111d后,处理的UFA、IUFA、C18:3、C18:3/IUFA分别是对照的94.74%、92.52%、87.87%、94.97%;处理的饱和脂肪酸、C16:1trans、C16:1/IUFA分别是对照的1.16、1.15、1.24倍.熏气112d后,会使极性脂和中性脂中的不饱和脂肪酸C18∶3含量,不饱和脂肪酸含量UFA和不饱和脂肪酸指数IUFA及C18:3/IUFA值下降.因此,长期低体积分数SO2处理会使细胞膜的脂肪酸组成发生变化,使不饱和脂肪酸含量下降,饱和脂肪酸含量上升,从而使细胞膜的功能发生变化.     

供热发展的未来展望

本文分析了燃煤集中供热的优缺点,并对未来城市供热的发展趋势提出了一些独特看法。     

2.5cm栎木地板毛坯的快速干燥新方法

采用干球温度不变、湿球温度连续下降的干燥新工艺对２．５ｃｍ 栎木地板毛坯用炉气间接加热木材干燥窑进行快速窑干试验，结果表明干燥周期较常规窑干燥缩短了４０％，锯材干燥质量良好，干燥基准操作方便。     

高速公路不同绿化模式环境效应分析

采用测定SO2、NO2和CO2气体含量的方法,研究了高速公路路侧不同绿化模式(绿化带、互通立交区、入口匝道区和服务区绿地)对空气的净化效果。测定结果表明:路侧绿化带对SO2有较明显的净化作用,互通立交区、入口匝道区和服务区的绿化对SO2和NO2均有较好的吸收净化作用,而高速路绿化对CO2含量的影响则较小。     

Rapid production of high-strength cement-bonded particleboard using gaseous or supercritical carbon dioxide

This study deals with the effects of curing treatment with gaseous and supercritical carbon dioxide on the properties of cement-bonded particleboard (CBP) manufactured by the conventional cold-pressing method. The hydration of cement and the mechanism of improvement were examined using X-ray diffractometry (XRD), thermal gravimetry (TG-DTG), and scanning electron microscopy (SEM) observations. The results are as follows: (1) The curing of cement was accelerated concomitantly with the improvement in mechanical and dimensional properties of CBP significantly by curing with gaseous or supercritical carbon dioxide. (2) Supercritical carbon dioxide curing imparted boards optimal properties at a faster rate than did gaseous curing. (3) Accelerated formation of calcium silicate hydrate and calcium carbonate and the interlocking of those hydration products on the wood surface are potentially the main reasons for the superior strength of carbon dioxide-cured boards.     

发动机用平板型空滤器流动阻力特性分析和改进

为减小平板型空滤器流动阻力以增大进气量,对平板型空滤器流动阻力特性开展了实验研究,获得了空滤器流动阻力随流量变化的规律和阻力构成成分。阻力随流量的增大而加速增大,滤芯阻力约占整个空滤器阻力的一半,入口流量为120 m 3/h时,总阻力为915.3 Pa,滤芯阻力为426.4 Pa。在实验获得滤芯阻力参数的基础上,提出采用多孔介质跃升模型对平板型空滤器内部流场开展三维数值仿真分析,结果表明,仿真结果与实验结果比较吻合,最大误差为5.67%。滤芯阻力同样约占整个阻力的一半,另一半阻力主要为出口处阻力,其余壁面阻力约占15%。最后,在实验和仿真分析的基础上,提出了改进模型并进行了仿真分析。结果表明,改进模型阻力有较大程度的下降,入口流量为120 m 3/h时,总阻力为588.2 Pa,较原始模型下降了32.2%;增大空滤器流通横截面积是减小阻力以增大进气量的有效手段,改进空滤器壁面的平滑性是补充措施。     

AN APPRONTMATE CALCULATING METHOD FOR WALL PLATES OF MAN'' S DRY GAS HOLDERS

The basic equations of wall plates of MAN' S dry gas holders are derived in this paper. According to the law of cylindrical bending given by the finite element results .we derive some approximate formula calculating the deflection and stresses of the wall plates from the basic equations. Compared with the known approximate calculating method.the method car. obviously increase the percision.     

DETERMINATION OF METALLIC IRON IN HIGH TITANIUM SLAG BY HEADSPACE GAS CHROMATNGRALHY

The following details are discussed in the present paper, after high titanium slag and H3PO4 is put in the closed system,the .reaction takes place under controlled temperature conditions, and the gas produced is collected. The two phases of gas liquid attain kinetic equilibrium, ihe gas above the liquid is used to make GC analysis with the aid of chromatographic column of 5A molecular sieve, TCD and N2 30ml/min. Satisfactory quantitative results can be achieved with simple instruments and uncomplicated operation technique.     

煤与瓦斯突出综合预测指标临界值的优化

为了提高煤与瓦斯突出预测的准确性、保障采掘工作面的安全、高效推进和降低防突工程成本,根据“三率”(预测突出率、突出预测准确率、不突出预测准确率)各自具有的合理区间属性和权重,以张集煤矿采掘工作面为例,采用区间数关联决策方法,得出综合预测指标 F ′的最优化区间为［370,380］;根据加权灰靶决策方法,得出预测指标临界值排序为400、390、380等;取最优化区间和排序靠前的临界值的交集,得到煤与瓦斯突出综合预测指标 F ′的临界值为380,并开展现场应用。结果表明,考虑评价指标的区间属性,并取预测指标区间与排序靠前的临界值的交集作为煤与瓦斯突出预测综合指标 F ′的最优临界值方法是合理的。