香蕉汁储藏过程中非酶褐变的研究

本文探讨了香蕉汁储藏中非酶褐变的原因与动力学。结果表明还原糖与氨基化合物发生的Maillard反应是造成香蕉汁储藏期间非酶褐变的主要原因。经与一级动力学和零级动力学模型拟合，推测香蕉汁储藏期间的非酶褐变符合零级动力学方程，其发生非酶褐变的活化能为80．46kJ／mol。     

热处理对鸭梨汁色泽和稳定性影响研究

研究了热处理对鲜榨鸭梨汁色泽和稳定性的影响及处理后4℃下贮藏期间鸭梨汁品质的变化。研究结果表明,不同温度和时间热处理后的鸭梨汁L值显著降低,ΔE值显著增加（p〈0.05）,透光率有不同程度的下降,一级动力学公式能很好地分析L值的变化。4℃下贮藏4周内,鸭梨汁色泽指标和稳定性指标随处理温度的变化存在不同程度的变化,表明不同热处理对鸭梨汁色泽和稳定性影响显著（p〈0.05）。     

黑曲霉固态发酵麻竹笋壳动力学研究

利用黑曲霉对麻竹笋壳进行固态发酵,每12 h取样,测定菌落总数,纤维素酶活,并基于Logistic和Luedeking-Piret方程,研究了黑曲霉固态发酵麻竹笋壳过程的菌体生长动力学,产物合成动力学。研究结果表明,模型模拟计算结果与试验结果吻合良好,该模型基本能反映黑曲霉固态发酵麻竹笋壳的过程。     

废纸制浆技术新进展

本文介绍了废纸制浆过程中供料技术、碎浆技术、筛选技术、脱墨技术、浮选技术、洗涤技术和污泥利用技术等方面在生产上的新发展。     

8种农药残留在小麦模拟储藏过程中的降解动力学研究

本文研究了8种农药残留（乐果、氰烯菊酯、氟环唑、戊唑醇、咪鲜胺、甲基毒死蜱、甲基嘧啶磷、毒死蜱）在小麦模拟储藏过程中的降解动力学。通过QuEChERS（Quick, Easy, Cheap, Effective, Rugged, Safe）前处理结合超高效液相色谱与三重四级杆质谱串联（UPLC-MS/MS）技术,对不同储藏时间的小麦中农药残留进行检测,结果表明：除氰烯菌酯外,其余7种农药降解均符合一级动力学模型,它们的残留降解速率随温度升高而加快,但受湿度影响不大;在10℃下,7种农药的降解动力学常数k的范围为0.0007~0.0042 d-1,半衰期t1/2为165~990.2 d;在35℃下,k的范围为0.0034 d-1~0.0408 d-1,t1/2为17~203.9 d ;在10℃和35℃下k值最大的分别为甲基嘧啶磷和乐果,k最小的分别为咪鲜胺和氟环唑。咪鲜胺具有最大的降解活化能Ea（87.29 kJ/mol),其k值受温度影响最大,而甲基嘧啶磷的Ea值最小（8.29 kJ/mol),其k值受温度影响也较小。而氰烯菌酯则非常稳定,即使在35℃下近6个月储藏过程中残留量几乎没有变化。     

采后小白菜叶绿体色素含量变化及其叶绿素降解动力学的研究

目的 探究采后小白菜贮藏过程中叶绿体色素的代谢变化及其叶绿素降解的动力学模型。方法 以采后“上海青”小白菜为试材, 分别将其贮藏于室温(20 ℃)、低温(2 ℃)及冰温(-0.5 ℃)条件下, 研究其总叶绿素、叶绿素a、叶绿素b、β-胡萝卜素及叶黄素的代谢变化, 并对其叶绿素的降解进行动力学模型拟合。结果 采后小白菜贮藏过程中总叶绿素、叶绿素a、叶绿素b、β-胡萝卜素和叶黄素均发生不同程度的降解, 低温和冰温贮藏均可减缓其降解, 其中冰温贮藏减缓效果最佳。叶绿素a含量与叶绿素b含量的比值、β-胡萝卜素含量与总叶绿素含量的比值以及室温贮藏条件下叶黄素含量与总叶绿素含量的比值均呈现不同程度的上升趋势, 而低温和冰温贮藏环境中的叶黄素含量与总叶绿素含量的比值总体则呈现下降趋势, 但贮藏6 d后下降不显著。此外, 叶绿素的降解反应符合零级动力学反应模型, 拟合调整决定系数(Adj.R2)均大于0.93, 降解活化能为95.53 kJ/mol, 降解动力学模型为k=6.51×1015?exp(9.553×104/RT)。结论 采后小白菜贮藏过程中叶绿体色素的代谢变化受贮藏温度影响较大, 其叶绿素降解反应符合零级动力学反应模型。     

阻抑催化动力学光度法测定柠檬酸

在稀硝酸介质中,柠檬酸能阻抑铁(Ⅲ)催化过氧化氢氧化酚红的褪色反应,据此建立了阻抑动力学光度法测定柠檬酸的新方法。方法检出限为0.10μg/mL,线性范围为0.70～4.0μg/mL。直接用于汽水中柠檬酸的测定,回收率为99%～102%,获得满意结果。     

Kinetics of Heterocyclic Amines Formation in Meat Emulsion at Different Fat Contents

The objectives of the study were to investigate the yield of heterocyclic amines (HA) in meat emulsion during heating as in cooking at different temperatures using the kinetic modeling approach and to determine the influence of fat content on the formation of HAs. Meat emulsion with two different fat contents namely extra lean (6 g/100 g) and regular (19 g/100 g) were used in the study. The samples were heated at 160, 180 and 200°C for times, varying from 5 to 40 mins. HAs namely IQx, MeIQx, and PhIP were identified and quantified using the HPLC. Formation of HAs was dependent on temperature, time, and fat content. It followed the first-order kinetics. Increasing fat content of samples resulted in lower HAs concentrations and lower activation energy of reaction. Fat enhanced formation of HAs in meat but apparently diluted available precursors for reactions.     

A simple model for deep dynamic stall conditions

The present study is focused on modeling of dynamic stall behavior of a pitching airfoil. The deep stall regime is in particular considered. A model is proposed, which has a low implementation and computational complexity but yet is able to deal with different types of dynamic stall conditions, including those characterized by multiple vortex shedding at the airfoil leading edge. The proposed model is appraised against an extensive data set of experimental (α,C_L) curves for NACA0012. The results of an existing widely used model, having comparable complexity, are also shown for comparison. The proposed model is able to well reproduce not only the classic curves of deep dynamic stall but also the curves characterized by lift oscillations at high angles of attack due to the shedding of multiple vortices. Furthermore, the model appears to be robust to variations of its parameters from the optimal values and of the airfoil geometry. Finally, the model is successfully implemented in a commercial CFD software and applied to the simulation of a vertical axis wind turbine within the actuator cylinder approach. The accuracy of the prediction of the turbine power coefficient in the whole rotation cycle is very good for the optimal working condition of the turbine, for which the model parameters were calibrated. Fairly good accuracy is also obtained in significantly different working conditions without any further calibration.     

高温煤焦油加氢裂解反应动力学研究

在360℃～400℃,氢气初压1MPa～2.5MPa,5min～40min以及0.5～3剂油比条件下,在自制的间歇式反应器上对高温煤焦油在超临界二甲苯中加氢裂解的宏观反应动力学进行了研究,建立起三集总宏观反应动力学模型.结果表明,该模型能较好反应高温煤焦油在超临界二甲苯中加氢裂解行为.在本实验条件下高温煤焦油在超临界二甲苯中加氢裂解反应时裂化反应的表观压力指数为-0.2111,表观剂油比指数为0.4033,表观活化能为15.765kJ/mol,指前因子为2.722min-1.MPa(0.2111);缩合反应的表观压力指数为-0.2884,表观剂油比指数为-0.4459,表观活化能为30.762kJ/mol,指前因子为18.952min-1.MPa(0.2884);总反应的表观压力指数为0.1609,表观剂油比指数为0.2265,表观活化能为39.049kJ/mol,指前因子为204.226min-1.MPa(-0.1609).