Dependence of Thermal Stability of an Engine Lubricating Oil on Usage Period

Mineral oil type lubricating oils have an important role in reducing engine wear. But after some period, depending on the oil quality, oil replacement is needed since the oil loses its properties. In this paper, an engine oil was tested in a 1300 cc engine car and the change of the thermal stability of the collected portions of oil at different usage periods were experimented by TG/DTG and DSC techniques. Results show that, as usage period increases lubricating oil contains more of the light components that distill at low temperatures. The increase in the peak maximum temperature, T_max, of the DTG, as usage period increases, proposes that the molecular mass of the oil increase, which presumably changes the viscosity characteristics. Moreover as the usage period increases some residue type components, which only can be destroyed at very high temperatures, are produced in oil phase. This revised version was published online in August 2006 with corrections to the Cover Date.     

用锥形量热仪研究聚乙烯膨胀阻燃体系的燃烧性

利用锥形量热仪在50kW·m^-2热辐照条件下,研究了含淀粉膨胀阻燃线性低密度聚乙烯(LLDPE)体系的燃烧性,获得了最大热释放速率、总热释放、有效燃烧热、最大烟产生速率、总烟释放量及质量损失速度等参数.实验结果表明:含淀粉膨胀阻燃剂能明显降低LLDPE的热释放速率、总热释放和有效燃烧热,淀粉作为膨胀型阻燃剂中的成炭剂,可以部分代替季戊四醇,而对热释放速率影响不大,达到了阻燃和降低成本的目的.该膨胀体系使烟释放变得缓慢,但总烟释放量明显增大.在燃烧时使LLDPE更早地发生热降解,但热降解速度变得缓慢.     

Pitzer方程应用于离子液体[Cnmim][H2PO4](n= 3, 4, 5, 6)溶解焓研究

在298.15 K下,利用等温环境溶解反应热量计,测定了离子液体[C_nmim][H₂PO₄] (n= 3, 4, 5, 6) (1-烷基-3-甲基咪唑磷酸盐)在水中不同浓度的摩尔溶解热(Δ_solH_m),根据Pitzer电解质溶液理论计算得到了标准摩尔溶解焓(Δ_solH_m⁰)和Pitzer焓参数：β_MX^(0)L, β_MX^(1)L,和C^ϕL,并计算了表观相对摩尔焓。通过推导讨论,得到了离子液体[C_nmim][H₂PO₄](n= 3, 4, 5, 6)同系物每摩尔亚甲基对标准摩尔溶解焓的贡献。     

TATB及其杂质的绝热分解研究

用加速热量仪研究了TATB及其杂质的绝热分解过程 ,得到了绝热分解温度和压力随时间的变化曲线以及温升速率随温度的变化曲线 ,根据绝热加速热量仪的温升速率方程和Arrhenius方程 ,计算了TATB绝热分解的动力学参数。结果表明 :TATB的初始热分解温度大于 2 90℃ ,反应系统最高温度大于 340℃ ,最大压力超过 1MPa ,而TCTNB和TCDNB存在多次放热反应 ,但每次放热量都很小 ,只有最后一次放热速率比较大。     

热致晶化高反射率SbOx薄膜的结构分析和光学性质

利用直流磁控反应溅射法制备了SbOx薄膜,利用X射线衍射分析仪和光谱仪分别研究了这种薄膜热致晶化的微观结构和光学性质的变化,并通过非晶态薄膜粉末的示差扫描量热实验测出不同加热速度条件下结晶峰温度,研究了这种薄膜的结晶动力学。发现沉积态SbOx薄膜为非晶态,非晶态SbOx薄膜在热致晶化过程中发生了两种变化,分别对应为较低温度下Sb晶体和较高温度下立方Sb2O3相的生成。退火后晶态薄膜中出现了单质Sb和Sb2O3,300℃退火后Sb2O3相含量最大。晶态薄膜的反射率均高于沉积态,在晶态薄膜中200℃退火的薄膜反射率最大。     

Experimental and predicted excess molar enthalpies of some working pairs for absorption cycles

In this work, the measured excess molar enthalpies of absorption heat pump working pairs (refrigerant + absorbent), viz. water + mono-, di- and tri-ethylene glycol, water + glycerol, and ethanol + di- and tri-ethylene glycol mixtures are presented at 298.15 K and ambient pressure using a Setaram Calvet C80 calorimeter. The experimental results are represented and correlated by a Redlich–Kister type equation. Modeling of the excess enthalpies has been performed using the UNIFAC molecular group-contribution method, and UNIQUAC Gibbs energy model. In addition, the data and results are used to predict the Gibbs energy of all binary systems. This allows a preliminary evaluation of the suitability of the binary systems as heat pump working pairs.     

氟吗啉合成工艺热危险性及动力学研究

氟吗啉是一种新型杀菌剂, 合成工艺热危险性和动力学研究将解决工程问题, 并保障安全生产. 采用差示扫描量热-热重分析仪(DSC-TG)测试主要原料、中间体和产品的热稳定性, 采用反应量热仪(RC1)研究反应热行为, 同时开展反应动力学研究. 研究结果显示, 主要中间体(3,4-二甲氧基苯基)(4-氟苯基)甲酮吸热分解温度为559.3 K, 乙酰吗啉吸热分解温度为478.2 K, 氟吗啉吸热分解温度为638.6 K. 氟吗啉合成反应摩尔放热量为15.44 kJ/mol, 绝热温升ΔT_ad为9.1 K, 本研究合成工艺的热危险性较小. 氟吗啉合成反应动力学方程为：r_A=kc_A^a=8.34×10^-3C_A^0.57, 对主要中间体(3,4-二甲氧基苯基)(4-氟苯基)甲酮的反应级数为0.57 级.     

Angular reconstruction of a lead scintillating-fiber sandwiched electromagnetic calorimeter

The Neighbor Cell Deposited Energy Ratio （NCDER） is a new method that is proposed to reconstruct incidence position in a single layer for a 3-dimensional imaging electromagnetic calorimeter （ECAL）. This method was applied to reconstruct the ECAL test beam data for the Alpha Magnetic Spectrometer-02 （AMS-02）. The results show that this method can achieve an angular resolution of 7.36±0.08°/√E＋0.28±0.02° in the determination of the photon＇s direction, which is much more precise than that obtained with the commonly-adopted Center of Gravity （COG） method （8.4±0.1°/E＋0.8±0.3°）. Furthermore, since it uses only the properties of electromagnetic showers, this new method could also be used for other type of fine grain sampling calorimeters.     

Study of linearity for a high dynamic range calorimeter

A high dynamic range calorimeter has been designed for the DArk Matter Particles Explore(DAMPE) satellite. It consists of 308 BGO crystals, multi-dynode readout PMTs and front end electronics system. We have built on previous research to show that BGO fluorescence should not be saturated by high electron energy density under DAMPE's energy range. A BGO fluorescence simulator is set up to calibrate the energy range of the dynodes, while a cosmic-ray unit is used to calibrate 1 MIP with the ADC count in dynode 8. Linearity is achieved for the dynamic range from 0.5 MIPs to 1.26×105MIPs. The requirements of DAMPE can thus be satisfied.     

聚乳酸/矿物填料复合材料的示差扫描量热研究

通过熔融共混法制备了一系列聚乳酸(PLA)/矿物填料复合材料.采用示差扫描量热(DSC)研究了含有碳酸钙(CaCO3)、蒙脱土(MMT)和凹凸棒土(AT)的聚乳酸复合材料在不同热历程中的结晶和熔融行为.研究发现,MMT和AT对PLA的慢速降温结晶无明显影响,而碳酸钙在慢速降温过程中能够有效促进PLA结晶;在2.5 K/min的降温速率下,结晶热焓随碳酸钙含量增加而增加;填料种类和含量会对复合材料升温过程的冷结晶和熔融产生较大影响,低含量矿物填料主要对PLA的冷结晶起成核作用,其中MMT成核效果最好.较高含量下不同填料会对PLA晶体形态产生影响,从而得到多样的DSC曲线变化.