MgZr4(PO4)6的反应及高温电性能研究

以Mg(OH)2、NH4H2PO4、ZrCl2O·8H2O为原料,在不同的热处理温度(800 ℃、900 ℃、1 000 ℃、1 100 ℃)下应用固相反应法合成磷酸镁锆(MgZr4,PO4)6(MZP)粉体,研究了其热重 示差扫描热(TG/DSC)图谱、物相组成、微观形貌和高温电性能。结果表明,900 ℃处理下可以合成纯相MZP粉体,且粉体能稳定存在。随着热处理温度的升高,出现了Zr2O(PO4)2第二相产物,其物量随着热处理温度的升高而增多。合成的MZP粉末具有2~5 μm大小不等的颗粒状,表面粗糙,并有更小颗粒聚集及呈不规则立方体状,还有极少量的形状为棒状,表面光滑,尺寸大小为2 μm的两种形态。随着温度的升高,MZP由于镁离子通道扩散能力的增加,试样的电导率提高了3个数量级。     

Relationships between intramuscular fat content, selected carcass traits, and fatty acid profile in bulls using a F2-population

The quality and nutritional value of beef is related to the amount of intramuscular fat (IMF) as well as to its fatty acid composition. In this study the relations between the IMF content and the total fatty acid composition, the fatty acids (FA) of triacylglycerols (TG) and the FA of phospholipids (PL) in longissimus muscle of F₂ Charolais × German Holstein crossbred bulls have been analysed. Polyunsaturated fatty acids (PUFA, C18:2n-6; C18:3n-3) and stearic acid (C18:0) are strongly positively correlated to IMF in longissimus muscle at the quantitative level (mg/100 g fresh tissue), but there are negative correlation coefficients for the relative proportion of these fatty acids to IMF. The relationships between IMF and the fatty acid profile of the subfractions TG and PL are lower compared to total muscle fat. Selected carcass fat traits are positively correlated to most of the fatty acids.     

山梨酸钠固相反应生产过程中的微观特征

采用山梨酸和碳酸钠固相反应生产山梨酸钠过程中,会出现反应体系温度突然升高,反应物粘接,反应不易进行彻底,碱的加入量超过化学反应比例等问题,从而影响反应的进行和产品质量.为解决这些问题,利用X-射线衍射、扫描电镜、差热及热重分析方法,对其固相反应过程的微观变化特征进行研究,结果表明:山梨酸与碳酸钠固相反应产生的热、水及研...     

溴化聚苯乙烯分子量对其热失重温度的影响

研究了不同分子量的溴化聚苯乙烯对其热失重温度的影响.     

Unmodified and Modified Surface Sisal Fibers as Reinforcement of Phenolic and Lignophenolic Matrices Composites: Thermal Analyses of Fibers and Composites

Summary: The study and development of polymeric composite materials, especially using lignocellulosic fibers, have received increasing attention. This is interesting from the environmental and economical viewpoints as lignocellulosic fibers are obtained from renewable resources. This work aims to contribute to reduce the dependency on materials from nonrenewable sources, by utilizing natural fibers (sisal) as reinforcing agents and lignin (a polyphenolic macromolecule obtained from lignocellulosic materials) to partially substitute phenol in a phenol‐formaldehyde resin. Besides, it was intended to evaluate how modifications applied on sisal fibers influence their properties and those of the composites reinforced with them, mainly thermal properties. Sisal fibers were modified by either (i) mercerization (NaOH 10%), (ii) esterification (succinic anhydride), or (iii) ionized air treatment (discharge current of 5 mA). Composites were made by mould compression, of various sisal fibers in combination with either phenol‐formaldehyde or lignin‐phenol‐formaldehyde resins. Sisal fibers and composites were characterized by thermogravimetry (TG) and DSC to establish their thermal stability. Scanning electron microscopy (SEM) was used to investigate the morphology of unmodified and modified surface sisal fibers as well as the fractured composites surface. Dynamic mechanical thermoanalysis (DMTA) was used to examine the influence of temperature on the composite mechanical properties. The results obtained for sisal fiber‐reinforced phenolic and lignophenolic composites showed that the use of lignin as a partial substitute of phenol in phenolic resins in applications different from the traditional ones, as for instance in other than adhesives is feasible.

Micrograph of the impact fracture surface of phenolic composite reinforced with mercerized sisal fiber (500 X).     

DRYING KINECTICS OF PADDY USING THERMOGRAVIMETRIC ANALYSIS

The thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to study the drying kinetics of the paddy. TG experiments were carried out at different heating rates (1, 3, 10 K/min) to study the drying kinetics. The Activation energy and pre exponential factors from the Arrhenious equation were calculated for the drying curves using ASTM and OZAWA-FLYNN WALL analysis. The results showed that the drying reaction was the second order reaction and the activation energy values changing with the partial mass loss representing that the drying reaction was of complex type of reaction. The isothermal drying curves predicted from the dynamic curves showed reasonably high mass loss occurred at moderate range of temperatures of 60-100°C.     

新型Ca／AC脱硫剂的研究

工业煤半焦经水蒸气活化制得的活性焦等体积浸渍硝酸钙溶液,经干燥和煅烧后制得新型脱硫剂Ca/Ac,呈现较高的脱硫活性,这源于活性组分钙与AC相互作用,使得在脱硫温度（200℃）Ca与SO2反应性增加。不同活化条件制得的活性焦比表面积不同,比表面积较大的AC制得的硫剂有较高的脱硫活性,这归因于活性组分钙在其表面的良好分散性。Ca/AC制备中由于与空气接触,表面有CaCO3形成,但不影响其脱硫活性。     

氨基树脂膨胀型阻燃剂处理环氧树脂的阻燃机理

合成了一种氨基树脂膨胀型阻燃剂(AIFR),将其用于环氧树脂(EP)中。采用热重、红外光谱和扫描电镜研究了阻燃EP的热解性能和阻燃机理。结果表明:AIFR用量为25%时,EP阻燃性能达到UL94V—0级,氧指数28.4%;AIFR使EP热解提前,热解活化能降低,剩炭增加,红外光谱中吸收峰强度减弱;AIFR对EP的热解具有催化成炭作用;AIFR阻燃EP具有很好的膨胀发泡效果,剩炭的连续性、韧性和强度得到了明显改善。