高压无功就地补偿装置几个问题的探讨

本文就高压无功就地补偿装置设计和应用中的有关问题,提出了观点和依据。重点对装置的保护设置、安全措施和结构设计等技术问题,结合应用实践进行分析并提出了新的见解。     

关于确定居住用地容积率的几点思考

住宅容积率是规划住宅项目建设的重要指标,对城市住宅的建设和发展起到了积极的控制和引导作用.随着社会的发展,以往的经验数值已经不能满足现实调控的需要,建设宜居城市需要科学地规划容积率指标,需要综合考虑经济、人口、基础设施、居住环境等相关因素的影响.     

低温溶液缩聚法制备聚间苯二甲酰对苯二胺

采用低温溶液缩聚法制备了聚间苯二甲酰对苯二胺(PPIA),讨论了单体浓度、单体物质的量配比、反应温度等因素对聚合反应的影响,并用红外光谱(IR)、热重分析(TG)、X射线衍射(XRD)、扫描电镜(SEM)对实验产物进行了测定。红外检测出的特征峰符合PPIA的结构特征,热重测得热分解速率最大温度在520℃左右,X射线衍射表明聚合物有明显结晶现象,并且扫描电镜显示下的聚合物结构聚集状态良好。     

拉曼光谱快速鉴别花生油掺棕榈油的研究

本文利用激光拉曼光谱实现了纯花生油中掺棕榈油的快速定性鉴别和定量分析.通过因子分析法的二维因子图,能够定性鉴别纯花生油和掺棕榈油的花生油;通过最小二乘法建立的拉曼光谱相对峰强度（Y）与掺入棕榈油的质量百分数（X）之间的线性方程（Y=-0.233 7X ＋0.506 8,R2=0.995 9）能够实现纯花生油掺棕榈油的定量分析.     

Formation and antioxidant activity of volatile compounds produced by heating glucose with tyrosine/histidine in water-ethanol and water-glycerol media

Volatile compounds prepared by heating glucose-tyrosine and glucose-histidine models in water-ethanol and water-glycerol media were studied under different water contents (0%, 25%, 50%, 75%, 100%, v/v). Aliphatic compounds, cyclopentenones, pyrazines, furans, furanones and pyrones were identified by GC–MS and analysed by factor analysis which showed that the presence of ethanol or glycerol in water could result in the increase of most volatile compounds in the Maillard reaction with the higher amount of volatile compounds formed in water-ethanol media, especially in the 50% ethanol medium. The measurement of antioxidant activity revealed that volatile MRPs prepared in water-ethanol media showed greater DPPH radical scavenging activity than those in water-glycerol media with the maximal DPPH radical scavenging activity observed in 100% ethanol medium for the glucose-tyrosine model and in 75% ethanol medium for the glucose-histidine model. Hence, water-ethanol medium could be used to promote the formation of volatile compounds, especially those with antioxidant activity.     

正反捻双股线结构及其拉伸性能的研究

探讨正反捻双股线结构及拉伸性能。分别使用棉纱和涤纶长丝制成正反捻双股线并对其进行加捻、结构扫描和拉伸试验。结果表明:随着捻度的增加,纱线中的一股因同向加捻而收缩成为芯纱(丝),另一股因退捻而伸长成为包缠纱(丝),其捻缩率主要取决于芯纱(丝)的捻缩率,包缠纱(丝)对芯纱(丝)的包缠角取决于两根纱(丝)的捻缩率差异;正反捻双股线的强力低于同号的普通双股线,存在两个临界捻系数峰值;其拉伸断裂曲线在捻系数较小时会出现双峰现象,当捻系数足够大时,则呈现单峰状态。认为该研究结论可为花式纱线和复合纱线的生产与研究提供一定的实践与理论支撑。     

基于生熟角度探讨15种板栗果实性状及营养品质的差异性

从生熟角度系统分析板栗仁的品质差异性。以15份不同产地的鲜板栗为原料,采用人工去壳去皮、隔水蒸煮熟化处理,测定板栗主要经济性状指标（出仁率、板栗仁单果重量、粒径及碎粒率）,并检测蒸煮前后板栗仁内在品质指标（可溶性糖、蔗糖、可溶性蛋白、淀粉、直链淀粉、多酚）。结果表明：经蒸煮熟化后,板栗仁可溶性糖含量、可溶性蛋白含量下降幅度依次为21.6 %~72.1 %、21.4 %~90.9 %;但大部分产地板栗仁的直链淀粉含量、多酚含量均呈上升趋势,而蔗糖含量呈下降趋势。应用因子分析及相关性分析,从11个指标参数筛选出评价板栗仁综合品质的核心指标为：板栗仁蔗糖含量、可溶性糖含量、多酚含量、可溶性蛋白含量及熟制板栗仁原料的直链淀粉含量。本研究结果为进一步丰富板栗仁综合品质评价体系提供了重要参考。     

金银花冲泡浸提的影响因素分析及状态参数优化

以提高水液中的营养成分和风味为目的，用保温杯冲泡，加盖水浸提金银花试验，探讨了冲泡浸提时间A、冲泡水温度B和溶媒浓度C等3个参数对液中的氨基酸浓度、可溶性固形物含量和pH值的影响。分析表明：冲泡水温度是阻碍金银花中的水溶性成分浸出的主要因素；冲泡浸提5min，水溶性成分大部分已浸出；增大溶媒浓度可提高冲泡浸提过程的推动力，加快水溶性成分浸出速度，但水液中的营养成分浓度或含量比例下降。通过均匀设计法优化的最佳冲泡浸提参数：溶媒浓度为15.5-18.7:1，冲泡水温度为77.5-95℃，浸提时间为2.5-18.1min。     

Pervaporation of flavors with hydrophobic membrane

Using a pervaporation process, a surface-modified hydrophobic membrane was used for recovery of esters which are volatile organic flavor compounds; ethyl acetate (EA), propyl acetate (PA), and butyl acetate (BA). A surface-modified tube-type membrane was used to evaluate the effects of the feed concentration (0.15–0.60 wt%) and feed temperature (30–50 °C) on the separation of EA, PA, and BA from dilute aqueous solutions. The permeation flux increased with the increasing feed ester concentration and operating temperature. EA, PA, and BA in the permeate were concentrated up to 9.13–32.26, 11.44–34.95, and 14.96–36.37 wt%, respectively. The enrichment factors for the 0.15–0.60 wt% feed solution of EA and BA were in the range of 48.5-62.8 and 97.7-101.5, respectively. Phase separation occurred in the permeate stream because the ester concentration in the permeate was above the saturation limit. This meant that selectivity of the membrane was high enough for the recovery of esters from dilute aqueous solution, even though the enrichment factor of the membrane was lower than that of non-porous PDMS membrane. The fluxes of EA, PA, and BA at 0.60 wt% (6,000 ppm) feed concentration and 40 °C were 254, 296, and 318 g/m².hr, which are much higher than those obtained with polymer membranes. In the case of non-porous PDMS at feed concentrations of 90-4,800 ppm and at 45 °C, it was reported that the permeate flux of EA was 1.1–5.8 g/m^2.h. Compared to non-porous PDMS, the surface-modified membrane investigated in this study showed a much higher flux and enough selectivity of esters.