用热分析技术研究巴比妥的动力学性能

用热分析法研究巴比妥的热失重过程并讨论升温速率对巴比妥热解过程的影响.结果表明,巴比妥热失重温度范围为温度160～220℃,质量失重率〉97%.巴比妥的分解过程分两个阶段进行,分解率α在0.2～0.45,用等转化率迭代方法求得失重的Ea=（148.468±0.674）kJ/mol,在0.55～0.90,求得Ea=（102.970±1.004）kJ/mol,巴比妥的分解过程在分解率α为0.45～0.55相互重叠,用主曲线法确定巴比妥失重过程两个阶段的最可几机理函数分别为G（α）=[-ln（1-α）]3/4和G（α）=[-ln（1-α）]1/2.     

热加工对鲤鱼质构的影响研究

通过质地剖面分析TPA(texture profile analysis),测定不同的加热温度和时间下鱼肉的硬度、咀嚼性、内聚性、弹性和回复性,通过其变化趋势,分析加热对鲤鱼肉质构和品质的影响。TPA结果:30℃低温加工的鱼肉的蛋白质降解适度,肉质结实,富有弹性,有咀嚼感,鲜嫩,可以最大限度的保持了原有营养和固有的风味。     

Influence of roasting conditions on the acrylamide content and the color of roasted almonds

ABSTRACT:  The influence of roasting conditions on the acrylamide content and on the color of roasted almonds of 3 cultivars was investigated. The temperature inside the almond kernel, the water content, the color, and the acrylamide content were determined at different roasting temperatures and times. The formation of acrylamide started only when the kernel temperature had exceeded approximately 130 °C. The activation energy for the acrylamide formation during the roasting of almonds was 123 kJ·mol⁻¹. The color as measured by the degree of brightness correlated well with the acrylamide content as acrylamide content increased with increasing darkness. Therefore, control of roasting temperature presents the critical factor for limiting the acrylamide concentration in the final product. At constant roasting conditions, almonds with higher initial moisture content contained less acrylamide after roasting, which is probably due to the influence of moisture on the development product temperature during roasting.     

两个链状稀土配位聚合物的合成、结构及热动力学

采用水热法合成两个稀土羧酸配位聚合物{Ln(H2L)(HL)(H2O)}n,{H3L=5-(对羧苄氧基)-1,3-苯二甲酸;Ln=La(1)、Nd(2)}.通过元素分析,红外光谱以及X-射线单晶衍射分析确定配合物的晶体结构.根据普适积分法对配合物的热重图谱进行热动力学分析.结果显示,两个配位聚合物属同构物,均为三斜晶系,P-1空间群.与中心稀土离子参与配位的两个5-(对羧苄氧基)-1,3-苯二甲酸配体中,一个配体中有两个羧基氧参与配位,而另一个配体只有一个羧基参与配位;配位单元LnO9的空间构型为扭曲的三帽三棱柱结构.LnO9通过羧基氧原子桥联成一维链状结构,链状结构之间通过氢键形成三维网络结构.热重分析显示配合物有很高的热稳定性,普适积分法求出配合物两次失重过程的热分解动力学的三因子,并得出决定两个配合物失重过程反应速率的关键步骤为随机成核和随后生长机理.     

芒果TPA质构测定优化及不同成熟度芒果质构特性分析

应用质构仪对芒果果肉进行TPA测试,探索压缩率、测试方向、测试速率等测试条件对不同成熟度芒果果肉质构测定结果的影响。结果表明,三种测试条件对不同成熟度芒果果肉的质构测定影响不同,采用果皮面向探头,测试和测后速率均为1 mm/s,压缩率20%~30%的测试条件能较好的表征芒果果肉的TPA质构特性。在芒果成熟过程中,随样品成熟度的增加,硬度、凝聚性、咀嚼性迅速下降,粘着性以成熟度2级最高,弹性变化不大;低成熟度芒果果肉质构参数的相关性较好,硬度和咀嚼性呈显著正相关性,高成熟度的芒果各质构参数间相关性不显著。本研究为质构仪应用于芒果果肉质构测定提供了参考。      

对双结构纱复合材料弯曲力学性能的实验分析

通过对玻璃纤维三维立体（3D）复合材料弯曲力学性能的实验进行分析，探讨了增强材料中不同比例的交织纱与非交织纱对其弯曲力学性能的影响。     

对双结构纱复合材料弯曲力学性能的实验分析

通过对玻璃纤维三维立体(3D)复合材料弯曲力学性能的实验进行分析,探讨了增强材料中不同比例的交织纱与非交织纱对其弯曲力学性能的影响。     

绿豆清蛋白功能特性及热特性研究

对水浸提法制备的绿豆清蛋白进行不同温度、不同pH、不同浓度对其功能特性的影响测试,并测试清蛋白的热变性温度。结果表明,在室温时,在等电点附近(pH4.6)绿豆清蛋白的溶解性、持水性最差,在偏离等电点时其溶解性、持水性显著提升;在中性条件下,在40℃时,溶解性、持水性最好;清蛋白吸油性随着温度升高而减弱;乳化性及乳化稳定性、起泡性及起泡稳定性随清蛋白浓度增加而增强,但增幅趋缓。热变性测试结果显示,绿豆清蛋白的初始变性温度100.1℃及焓变值ΔH(3.382J/g),说明清蛋白热稳定性较好。      

相变材料在消防服中的应用及可行性分析

火灾作业环境下,应用于消防服系统的相变材料对高温环境温度突变具有一定的缓冲、抑制作用。本文回顾评价了国内外相变材料应用于消防服研究的现状,分别从降低热应力、提高热舒适性能及抑制温度突变、提高消防服整体热防护性能两个方面的应用进行综述分析;并对火灾环境下使用的有机石蜡类相变材料的封装方法与阻燃处理进行了总结性分析探讨。基于上述应用情况总结,论文最后出对相变材料抑制消防服内温度突变可行性的分析,并思考了将来相变材料应用于消防服装备的研究发展趋势。     

Thermal properties of combat uniforms treated with microencapsulated octadecane and change in clothing microclimate via thermal manikin

This study examined how the heat storage property and the heat release property of three different PCM (Phase Change Material) treatment concentrations of combat uniform fabrics affected microclimate inside clothing after the octadecane-treated fabrics were made into garments. Three combat uniforms were constructed with fabrics treated by three different octadecane concentrations (0, 8, and 16%) at the same curing temperature of 113.6 °C. The thermal properties of the octadecane-treated fabrics were acquired by using DSC (Differential Scanning Calorimeter) analysis. Also, water vapor and air permeability were measured before the thermal comfort of the octadecane-treated combat uniforms was evaluated. And then, a thermal manikin was used to measure skin temperature, skin humidity, and microclimate temperature, while the chamber was set at various environmental temperatures (0, 0–35, 35, and 35–0 °C). And, to analyze the differences among skin temperature, skin humidity, and microclimate temperature of the garments according to the three different octadecane concentrations, ANOVA and a post hoc test were conducted. As a result, heat of fusion and heat of crystallization (ΔH_f and ΔH_c) were observed to increase as the octadecane concentration increased. The 8% octadecane-treated fabrics had 3.56 J/g of ΔH_f, 3.80 J/g of ΔH_c, and the 16% octadecane-treated fabrics had 7.46 J/g of ΔH_f, 7.44 J/g of ΔH_c. Also, the more octadecane was added, the less water vapor and air permeability had the fabrics because many open spaces were covered due to the microcapsules after octadecane treatment. It might influence on clothing microclimate. However, the 8% octadecane-treated garment (G1) exhibited less differential skin temperature and humidity and clothing microclimate temperature than the 16% octadecane-treated garment (G2) even though the octadecane concentration was lower. It means that the 8% octadecane-treated garment exhibited better thermal performance than the 16% octadecane-treated garment. This is because the higher octadecane concentration caused the fabric to become stiffer, thereby causing the still air layer to decrease the thermal insulation efficiency and the octadecane treatment was not affected. It differed from the result of the thermal properties (ΔH_f and ΔH_c) of the octadecane-treated fabrics. The reason for this result is that when the thermal manikin wore the octadecane-treated garments, various factors had effects on thermal properties such as environmental aspects, physiological aspects, and clothing aspects.     

差示扫描量热法对金枪鱼鱼油热氧化动力学研究

利用差示扫描量热法(DSC)研究了金枪鱼鱼油的热氧化动力学.通过对DSC曲线的分析表明,金枪鱼鱼油的酰基甘油组成复杂,脂肪酸种类比较多.用Flynn-Wall-Ozawa法和Kissinger法计算金枪鱼鱼油的热氧化反应动力学参数,两种计算方法得到的动力学参数具有一致性.     

Effect of drying temperatures on starch-related functional and thermal properties of acorn flours

The application of starchy flours from different origins in food systems depends greatly on information about the chemical and functional properties of such food materials. Acorns are important forestry resources in the central and southern regions of Portugal. To preserve these fruits and to optimize their use, techniques like drying are needed. The effects of different drying temperatures on starch-related functional properties of acorn flours obtained from dried fruits of Quercus rotundifolia (QR) and Quercus suber (QS) were evaluated. Flours were characterized for amylose and resistant starch (RS) contents, swelling ability, and gelatinization properties. Drying temperature mainly affected amylose content and viscoamylographic properties. Amylograms of flours from fruits dried at 60 °C displayed higher consistency (2102 B.U. and 1560 B.U., respectively, for QR and QS). The transition temperatures and enthalpy were less affected by drying temperature, suggesting few modifications in starch structure during drying. QR flours presented different functional properties to those obtained from QS acorn flours. The effect of drying temperatures were more evident in QR.     

相变调温纺织品的热性能测试方法与指标

论述了相变调温纺织品热性能的测试方法（热分析法、TRF测试法、暖体假人法、微气候仪法、步冷曲线法）以及表示指标（导热系数、相变温度与相变焓、循环性、保暖性、暖体假人热阻、ACR值）．     

绿豆-小麦混合粉的流变学和热力学特性研究

以小麦粉、绿豆粉为原料,研究绿豆-小麦混合粉面团的形成特性、流变学特性、热力学特性,为绿豆小麦粉复合食品的加工及品质控制提供参考。结果表明,添加绿豆粉对绿豆-小麦混合粉的物性有显著影响;随着绿豆粉添加量的增加,混合粉面团的吸水率、形成时间、稳定时间、评价值降低、弱化值增加;最大拉伸阻力、延伸度降低;热焓呈非线性降低,糊化温度增加;储能模量、损耗模量减小,黏弹性降低。     

方便米饭原料适应性的因子、聚类分析研究

不同品种的大米对方便米饭的质量有很大的影响。本文通过因子分析、聚类分析对方便米饭的原料适应性进行研究,得到适宜加工成方便米饭的稻米原料的12个品质指标最佳取值范围:最低粘度1300~2000c P,最终粘度2000~2800c P,峰值粘度2000~2500c P,回生值900~1200c P,峰值时间>6min,糊化温度63~75℃,直链淀粉含量15.5%~17.5%(干基),蛋白含量<8%(干基),吸水率230%~275%,膨胀体积300%~340%,米汤碘蓝值>0.18,米汤干物质>20mg/g。通过这些指标可以对优质稻米品种进行有效筛选,为方便米饭工业化生产提供客观依据,同时为食味优良的稻米育种工作提供了理论依据。      

苯乙烯改性丙烯酸酯类乳液粘合剂的制备及热性能分析

探讨了预乳化种子乳液聚合法制备苯乙烯改性丙烯酸酯类乳液粘合剂(SA).研究了苯乙烯单体含量对胶膜吸水性和胶接抗剥离性能的影响,利用差示扫描量热仪(DSC)和热重分析仪(TG)测试了SA的热性能.结果表明:丙烯酸酯类共聚物分子链中引入苯乙烯后,提高了共聚物分子链的耐水性和耐热性,玻璃化转变温度升高;将其涂膜于棉织物表面,棉织物的热分解温度提高至370℃以上,具有较好的热稳定性.     

Thermal and rheological properties of L-polylactide/polyethylene glycol/silicate nanocomposites films

The melt rheology and thermal properties of polylactide (PLA)-based nanocomposite films that were prepared by solvent casting method with L-PLA, polyethylene glycol (PEG), and montmorillonite clay were studied. The neat PLA showed predominantly solid-like behavior (G' > G″) and the complex viscosity (η*) decreased systematically as the temperature increased from 184 to 196 °C. The elastic modulus (G') of PLA/clay blend showed a significant improvement in the magnitude in the melt, while clay concentration was at 6% wt or higher. At similar condition, PEG dramatically reduced dynamic modulii and complex viscosity of PLA/PEG blend as function of concentration. A nanocomposite blend of PLA/PEG/clay (74/20/6) when compared to the neat polymer and PLA/PEG blend exhibited intermediate values of elastic modulus (G') and complex viscosity (η*) with excellent flexibility. Thermal analysis of different clay loading blends indicated that the melting temperature (T(m)) and glass transition temperature (T(g)) remained unaffected irrespective of clay concentration due to immobilization of polymer chain in the clay nanocomposite. PEG incorporation reduced the T(g) and the T(m) of the blends (PLA/PEG and PLA/PEG/clay) significantly, however, crystallinity increased in the similar condition. The transmission electron microscopy (TEM) image of nanocomposite films indicated good compatibility between PLA and PEG, whereas clay was not thoroughly distributed in the PLA matrix and remained as clusters. The percent crystallinity obtained by X-ray was significantly higher than that of differential scanning calorimeter (DSC) data for PLA.     

季戊四醇相变性能及其复合毡片蓄热性能表征

选用季戊四醇(PER)作为相变蓄热材料,玻璃纤维毡作为相变材料基材,采用热压复合法研制用于高温热防护的轻质柔性蓄热材料——PER复合毡片,并通过缝制的方式与玻璃纤维针刺毯复合制备复合织物。对PER的相变行为进行测量,发现PER具有高相变温度(177.9℃)和高相变焓(308.1 J/g),但直接暴露在210.0℃以上的高温空气中会发生老化,颜色泛黄,且其相变焓下降20%;在同样的热空气环境中重复5次升降温循环后,相变焓仅为94.1 J/g。采用织物防火隔热可靠性评价装置对复合织物进行测试,重复3次燃烧发现,不含PER的复合织物的正、反表面中心绝热温差平均为193.0℃,而含PER的复合织物的正、反表面中心绝热温差平均为264.0℃,后者的绝热温差比前者高71.0℃,提高了37%。热压复合法制备的PER复合毡片可用于高温防护服装内,实现对热冲击流的耗散与限温作用,从而达到隔热延时的效果。