TEAM实验及应用

ＴＥＡＭ实验及应用郑秀歧，魏新章，郭顺一、关于ＴＥＡＭ实验八十年代以来，澳大利亚羊毛研究开发理事会通过了一项关于羊毛附加测试评定（ＴＲＩＡＬＳＥＶＥＡＬＵＡＴＩＮＧＡＤＤＩＴＩＯＮＡＬＭＥＲＳＵＲＥＭＥＮＴ）项目的计划，简称“ＴＥＡＭ”项目。以使毛丛...     

沙田柚饮料的降血脂作用研究

以８周龄ＢＡＬＢ／Ｃ雄性小白鼠为实验动物，饲以高脂饲料造成实验性高血脂模型，分别灌胃不同浓度的沙田柚汁各１ｍｌ，高脂对照组和空白对照组则灌胃１ｍｌ的生理盐水，饲喂常规饲料，５０天后采尾血测定血清总胆固醇（ＴＣ）、甘油三酯（ＴＧ）、高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）含量和卵磷脂胆固醇酰基转移酶（ＬＣＡＴ）的相对活性，并计算出低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）和极低密度脂蛋白胆固醇（ＶＬＤＬ－Ｃ）浓度及动脉硬化指数ＡＩ（ＴＣ－ＨＤＬ－Ｃ／ＨＤＬ－Ｃ）。结果表明，沙田柚汁饮料能够明显降低实验性高血脂小鼠血清ＴＣ、ＴＧ、ＬＤＬ－Ｃ、ＶＬＤＬ－Ｃ和ＡＩ（Ｐ＜０．０５或Ｐ＜０．０１），并能使ＨＤＬ－Ｃ含量及ＬＣＡＴ相对活性显著升高（Ｐ＜０．０１），由此说明沙田柚汁具有降低血脂、防止动脉粥样硬化的作用。     

阿力甜及其FAO／WHO（1995）标准

阿力甜及其ＦＡＯ／ＷＨＯ（１９９５）标准凌关庭（上海市食品工业研究所上海，２０００５１）阿力甜（Ａｌｉｔａｍｅ）亦称Ｌ－天门冬酰－Ｄ－丙氨酰胺（Ｌ－Ａｓｐａｔｙｌ－Ｄ－ａｌａｎｉｎｅａｍｉｄｅｓ），系统名Ｌ－α－Ａｓｐａｒｔｙｌ－Ｎ－（２，２，４，４...     

L-异亮氨酸高产菌育种机理的初步研究

研究了黄色短杆菌生物合成Ｌ－异亮氨酸代谢控制途径，结果表明，选育Ｌ－异亮氨酸高产菌必须首先活化磷酸烯醇式丙酮酸羧化酶（ＰＣ）、天冬氨酸激酶（ＡＫ）、高丝氨酸脱氢酶（ＨＤ）、苏氨酸脱氢酶（ＴＤ）和乙酰羟基酸合成酶（ＡＳ）这五个关键酶，并减弱由丙酮酸激酶（ＰＫ）、柠檬酸合成酶（ＣＳ）、天冬氨酸β－脱羧酶（ＡＤ）、二羟吡啶二羟酸合成酶（ＰＳ）和高丝氨酸－Ｏ－转乙酰酶（ＨＴ）引起的五条分支代谢强度，从而强化生物合成Ｌ－异亮氨酸的主代谢流。根据这一育种思想，以黄色短杆菌（ＢｒｅｖｉｂａｃｔｅｒｉｕｍｆｌａｖｕｍＡＴＣＣ１４０６７）为出发菌株，采用相关的氨基酸结构类似物进行定向育种，有目的地活化ＰＣ、ＡＫ、ＨＤ、ＴＤ和ＡＳ等酶，筛选获得的Ｌ－异亮氨酸高产菌ＺＱ－４，产酸达２８～３０ｇ／Ｌ．     

DGL—龟裂树脂及应用

ＤＧＬ—龟裂树脂及应用冷冰，王晓航，杨昊鹏，张云霞，徐卫国（丹东轻化工研究院１１８００２）ＤＧＬＣｒａｃｋｉｎｇＲｅｓｉｎａｎｄＩｔｓＡｐｐｌｉｃａｔｉｏｎ￥ＬｅｎｇＢｉｎｇ；ｅｔ．ａｌ．（ＤＣＩＬＩ１１８００２）Ａｂｓｔｒａｃｔ：Ｔｈｅｐｒｅｐａｒ...     

国产α—乙酰乳酸脱羧酶的应用研究

本文介绍了α－乙酰乳酸脱羧酶（ＡＬＤＣ）在啤酒酿造中的应用，对国产酶和进口酶做了对比试验。从ＡＬＤＣ的使用量、不同的发酵条件以及对啤酒风味的影响等几方面进行了探讨。     

二种重组α-乙酰乳酸脱羧酶在啤酒生产中降低双乙酰的作用

利用已构建的含有短芽胞杆菌（Ｂａｃｉｌｌｕｓｂｒｅｖｉｓ）和产气肠杆菌（Ｅｎｔｅｒｏｂａｃｔｅｒａｅｒｏｇｅｎｅｓ）、α -乙酰乳酸脱羧酶（α -ａｃｅｔｏｌａｃｔａｔｅｄｅｃａｒｂｏｘｙｌａｓｅ,α -ＡＬＤＣ）基因的工程菌株 ,并使它们分别在大肠杆菌中高效表达 ,获得重组α -ＡＬＤＣ。在实验室 ,用２Ｌ体积的麦芽汁进行啤酒生产试验 ,添加２种重组α -ＡＬＤＣ后 ,使啤酒中的双乙酰含量快速下降到或始终保持在０．１ｍｇ／Ｌ以下。证明得到的重组α -ＡＬＤＣ能有效地降低啤酒中双乙酰含量。这２种重组α -ＡＬＤＣ可进一…     

籽粒苋食品降血脂作用的实验研究

在高脂饲料中分别添加２０％的籽粒苋食品－健乐粉或健安粉，饲喂ＢＡＬＢ／Ｃ雄性小鼠５０天，观察这两种食品对小鼠诱发高脂血症的影响。结果表明，健乐粉和健安粉能阻抑高脂肪饲料小鼠血清总胆固醇（ＴＣ）和甘油三酯（ＴＧ）的升高，显著提高高密度脂蛋白胆固醇（ＨＤＬ－ｃ）的含量和卵磷脂胆固醇酰基转移酶（ＬＣＡＴ）的相对活性，并且能降低低密度脂蛋白胆固醇（ＨＤＬ－ｃ）含量和动脉硬化指数（ｐ〈０．０５或Ｐ〈０．０１     

浅析绞棒位置对织造的影响

Ａ：织口；Ｄ：绞棒；Ｅ：后梁；ＢＣ：综框；ＡＤ：经位置线；Ｌ１：梭口前部长度；Ｌ２：梭口后部长度；Ｈ：梭口高度。从图（一）可知，梭口大小和绞棒位置直接相关，经丝在综平时，ＡＤ段经丝长为：Ｌ＝Ｌ１＋Ｌ２但经丝在形成梭口时，由于经丝各向上、向下二个方向移...     

梳棉机和并条机纤维流的非接触式测量技术

气流状态对纺纱准备工艺过程有巨大影响，因为气流的状态不仅会影响纤维的运动关系和实际工艺过程，而且会影响到杂质的去除。纤维状物质和非需要的杂质粒子的分离需要由气流来实现。研究人员采用新的测试技术，如使用ＬＤＡ（激光多普勒测速仪）已经能够研究气流和纤维的速度。ＬＤＡ技术通过非接触式方法在生产状态下测定纤维速度而且不会影响气流状态。由于这种测试斩传感器小而且容易操作，故可应用于难以接触的环境中。因而，使     

多通道烘缸通道内流体流动特性数值模拟研究

探讨了多通道烘缸内流体通过通道时的流动特性,建立了多通道烘缸通道的计算流体力学模型,并用计算流体力学软件FLUENT模拟通道内在不同气相折算速率及不同液相折算速率工况下,通道内气液两相分布及其沿通道壁面方向的压力降,得出了通道内流型的变化情况,为多通道烘缸的流动与传热机理研究提供了理论依据。     

溢流染色机圆喷嘴流场建模与涡流场仿真分析

针对喷嘴内部气液两相流流动特性对织物染色产生的影响,建立计算流体动力学数学模型,对喷嘴内部液相的流动特性及液相流动对气相产生的影响进行三维模拟仿真,并根据仿真结果分析喷嘴盖内气体动静态压力的变化及喷嘴内染液的速度场和压力场的分布.研究结果表明:液相的快速运动引起喷嘴盖内气相的动态脉动,喷嘴盖内压力为负值,喷孔处液相的速...     

金属丝径大小对液膜流动影响的CFD研究

精馏过程气液两相流动分布特征对分离效率具有重要影响,为研究金属丝网波纹填料表面液膜流体动力学特性,建立基于VOF法的液膜在金属丝网表面上的气—液两相逆流CFD模型,并根据液膜流动特点考虑了表面张力动量源项和气液界面作用力动量源项。模拟结果与文献流动形式相符,表明文中提出的CFD液膜流动模型具有一定的可靠性。文中主要考察丝径大小对液膜流动的影响,模拟结果表明适当改变丝径的大小有助于改善液膜的稳定,对于提高丝网填料气液之间的传质效率有重要意义。     

大产量气垫式皮带输送机内部流场分析

基于计算流体力学对气垫式皮带输送机内部气体流场进行仿真模拟,根据内部流场运行状态并结合实际工作载荷,求出流场最优进风速度,最佳气孔大小以及最理想气垫气膜厚度,同时对气孔的形状进行优化设计,为气垫式皮带输送机的设计提供理论依据。     

Mathematical modeling of the heat transfer and flow field of liquid refrigerants in a hydrofluidization system with a stationary sphere

Hydrofluidization is a method of chilling and freezing of foods that uses a circulating system that pumps the refrigerating liquid upwards through orifices and/or nozzles into a refrigerating vessel, thereby creating submerged agitating jets and increasing heat transfer to foods during freezing. The objective of this work was to develop a model to estimate the fluid flow and heat and mass transfer in a hydrofluidization system. A study case of modeling and validating the heat transfer to a single stationary copper sphere of 20-mm diameter impinged by a single round jet of liquid was carried out using computational fluid dynamics. The simulations were performed using parameters such as: velocity of the liquid at the orifice exit (2.36–7.07 m s⁻¹), temperature of the liquid refrigerant (−5 to −15 °C) and distance between the orifice and the stagnation point of the sphere (1 and 5 cm). In general, the errors of the model were in the order of magnitude of the uncertainty of the experimental data of Nusselt number averaged over the sphere surface. Also, the simulated heat transfer and flow field parameters were comparable with those obtained in literature for similar systems.     

Plasma metabolome alteration in dairy cows with left displaced abomasum before and after surgical correction

Left displaced abomasum (LDA) leads to substantial changes in the metabolism of dairy cows. Surgical correction of LDA can rapidly improve the health of cows; however, changes in metabolism following surgery are rarely described. To investigate the changes of plasma metabolome in cows with LDA before and after surgical correction, blood samples were collected from 10 healthy postpartum cows and 10 cows with LDA on the day of diagnosis, then again from the LDA cows 14 d after surgery. Serum nonesterified fatty acid, β-hydroxybutyric acid, cortisol and histamine concentration, and antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activities were evaluated, and the metabolic profile in plasma was analyzed using ultra-high-performance liquid chromatography time-of-flight mass spectrometry. The results demonstrated that cows with LDA experienced severe negative energy balance and oxidative stress, which can be improved by surgical correction. The metabolic profile was analyzed using multidimensional and univariate statistical analyses, and different metabolites were identified. In total, 102 metabolites differed between cows with LDA and healthy cows. After surgical correction, 65 metabolites changed in cows with LDA, compared with these cows during the LDA event. Following surgical correction, AA levels tended to increase, and lipid levels tended to decrease in cows with LDA. Pathway analysis indicated marked changes in linoleic acid metabolism, Arg biosynthesis, and Gly, Ser, and Thr metabolism in cows at the onset of LDA and following surgical correction. Surgical treatment reversed the changes in AA and lipid metabolism in cows with LDA.     

食品中有机磷杀虫剂残留分析方法的研究进展

对食品中有机磷杀虫剂(organophosphorus pesticides,OPPs)残留分析技术及其进展进行了综述。评述了前处理方法如固相萃取、基体固相分散萃取、超临界流体萃取、加速溶剂萃取、固相微萃取和液相微萃取等技术在分析中的应用。概述了气相色谱、液相色谱及其联用技术、免疫分析技术、超临界流体色谱和毛细管电泳等检测技术用于分析食品中OPPs的优势和局限性,并展望了未来该领域研究的发展趋势。     

CFD analysis of the convection flow in the pan during induction heating and gas range heating

One difference between induction heating (IH) and gas range heating (GRH) is that, because the heating location of the pan is different, the convection in the pan is different. In particular, in cooking situations in which solids are mixed with liquids, such as the boiling of soup containing solid foods, the natural convection flow in the pan may affect food quality. The convection in the pan during IH and GRH was analyzed by using computational fluid dynamics (CFD), and the temperature distribution and the flow velocity distribution in the pan were obtained. These results were then compared with the measurement results. In GRH, the heat flux at the wall of the pan was obtained by experiment, and it was used for the analysis as a boundary condition. In IH, the heat generation distribution obtained by electromagnetic field analysis was used for the analysis as the boundary condition. Differences in convection flow in the pan during IH and GRH were observed by CFD modeling especially at the initial stage of heating. The simulated convection in the pan showed the same tendency as the captured movement of the tracer particle using flow visualization.     

接枝PVDF膜吸收器中CO2吸收特性和传质规律的研究

本文以CO2为吸收气体,NaOH为吸收液,研究了N-异丙基丙烯酰胺(PNIPAM)接枝的PVDF中空纤维膜吸收器吸收二氧化碳的吸收特性以及传质规律,并建立膜吸收器中二氧化碳的传质模型。研究结果表明:PNIPAM接枝PVDF中空纤维膜吸收器的CO2吸收率随吸收液浓度和吸收液的流量的升高而升高,随气体流量升高而降低;在实验操作条件下,较佳吸收二氧化碳的工艺参数为:吸收液浓度为0.4 mol/L,吸收液流量为16 L/h,气体流量为250 L/h,气液两相流动方式采用逆流方式。此时,二氧化碳的吸收率接近100%;而对二氧化碳气体吸收过程中传质的研究得出,总传质系数KG=17.5～26.3×10-5mol.m-2.s-1.KPa-1,传质通量NCO2=3.8～7.6×10-6mol.m-2.s-1;采用PNIPAM接枝PVDF中空纤维膜吸收器,NaOH水溶液吸收CO2具有良好的吸收效率。     

低场核磁技术结合化学计量学法快速检测掺假牛奶

应用低场核磁共振技术结合主成分分析法(PCA)、偏最小二乘判别法(PLS-DA)、线性判别法(LDA)对掺水、食盐、尿素和蔗糖的牛奶及纯牛奶进行测定。结果表明:在主成分得分图中,不同掺假牛奶随掺假物质的掺假比例呈一定规律性分布,并得到了很好的区分。利用PLS-DA和LDA方法建立不同掺假牛奶的判别模型,对掺水、掺尿素牛奶的判别准确率均为100%,掺食盐牛奶的判别准确率分别为83.33%和100%,掺蔗糖牛奶的判别准确率分别为73.33%和76.67%。可见PCA法、PLS-DA法、LDA法可用于快速处理分析低场核磁共振数据,并且LDA法鉴别准确率最高。