AN EVA/UNMODIFIED NANO-MAGNESIUM HYDROXIDE/SILICONE RUBBER NANOCOMPOSITE WITH SYNERGISTIC FLAME RETARDANCY

A novel EVA/unmodified nano-magnesium hydroxide(NMH)/silicone rubber ternary nanocomposite was prepared by using a special compound flame retardant of NMH and silicone rubber(CFR).The flammability of the ternary composite was studied by cone calorimeter test(CCT).Synergistic effect on flame retardancy was found between silicone rubber and NMH.EVA/CFR ternary nanocomposite showed the lowest peak heat release rate(PHRR)and mass loss rate (MLR)among the samples of virgin EVA,EVA composites.The synergistic flame retardancy of silicone rubber and NMH in EVA system is attributed to the enhanced char layers in the condensed phase that prevents the heat and mass transfer in the fire.     

Calorimetric study and thermal analysis of [Gd4/3Y2/3(Gly)6(H2O)4](ClO4)6·5H2O and [ErY(Gly)6(H2O)4](ClO4)6·5H2O (Gly: glycin)

Two solid-state coordination compounds of rare earth metals with glycin, [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O and [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O were synthesized. The low-temperature heat capacities of the two coordination compounds were measured with an adiabatic calorimeter over the temperature range from 78 to 376 K. [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 342.90 K, while [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 328.79 K. The molar enthalpy and entropy of fusion for the two coordination compounds were determined to be 18.48 kJ mol⁻¹ and 53.9 J K⁻¹ mol⁻¹ for [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, 1.82 kJ mol⁻¹ and 5.5 J K⁻¹ mol⁻¹ for [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, respectively. Thermal decompositions of the two coordination compounds were studied through the thermogravimetry (TG). Possible mechanisms of the decompositions are discussed.     

用于多波长高功率激光能量测量的体吸收能量计

叙述体吸收激光能量计的原理及物理模型，给出其性能参数及测试方法，分析它在神光Ⅱ装置中对三种波长激光能量测量的取样方式及测量精度。     

闪烁体瓦片/光纤量能器辐照损伤的进一步研究

研究了由不同闪烁体瓦片/光纤材料组成,或材料相同但构造不同的量能器模型的辐照损伤.用北京正负电子对撞机(BEPC)的电子试验束(1.1或1.3GeV)辐照了十个量能器模型.通过测量在不同累积剂量和在量能器内的不同位置上的光输出,对辐照损伤作出定量分析.还研究了损伤后的恢复及损伤与环境气体的关系.通过数据拟合发展了辐照损伤对剂量及对深度断面的校正方法.     

工作于非标准环境下体吸收型激光能量计的研制

研究了能直接工作于非标准环境下的体吸收型激光能量计.由能量计热传导、热对流、热辐射的单位时间热交换方程推导出单位时间内能量计升温过程中热能损失的数学模型,根据数学模型对能量计整个升温过程的热损失进行补偿,使得能量计对于不同脉冲长度入射激光的测量结果重复性由4.7%提高到了0.6%,消除了能量计热损失给测量带来的不利影响.针对环境温度从-40℃变化到70℃测温用铜-康铜热电堆对1℃温差响应电压剧增30%的问题,在环境试验箱进行不同环境温度下的激光能量测量实验,得出了能量计不同环境温度下测量结果的修正系数,并利用最小二乘法建立了修正系数同环境温度之间的函数关系,使得环境温度对测量结果的影响得到了修正.     

Understanding the performance of CMS calorimeter

The performance of the CMS hadron calorimeter is studied using test beam facilities at CERN. Two wedges of brass-scintillator calorimeter are exposed to negative and positive beams with momenta between 3 and 300 GeV/c. Light produced in the scintillators are collected using wavelength shifting fibres and read out using hybrid photodiodes. Each of the wedges has 17 layers of scintillators. In one of these wedges signal from all 17 layers are grouped together while in the other each layer is read out separately. The response, energy resolution, longitudinal and lateral shower profiles are measured. on behalf of the CMS Collaboration     

在羊八井测量初级宇宙线直达质子研究质子和空气核非弹性作用截面

提出了一种在高海拔通过测量直达质子来确定质子和空气核(p-air)的非弹性作用截面的方法, 并通过Monte Carlo模拟, 研究了其可行性. 假定将一台类似于KASCADE的强子量能器设置在西藏羊八井ARGO探测器的中央,选择大气簇射(AS)轴心落在强子量能器内的事例, 用全覆盖ARGO阵列作AS的反符合,用强子量能器测量非伴随的高能强子,即能以已知的效率得到一个直达质子事例样本. 利用这个样本,本工作以1%—2%的精确度还原了Monte Carlo模拟中所使用的p-air非弹性作用截面, 从而证明了这一方法的可行性.     

The interaction between sodium carboxymethylcellulose and water

A differential scanning calorimeter has been used to study the nonfreezing of water in a series of solutions of sodium carboxymethylcellulose. In particular, the effects of molecular weight, degree of substitution, and particle size have been investigated. The results show that large amounts of water are associated with all the samples of sodium carboxymethylcellulose, suggesting a multilayer arrangement of water molecules about the solute. A change in degree of substitution has some effect on the hydration, but it appears less significant than a change in molecular weight.     

热导式热量计冷却常数的化学标定法

热导式热量计是热力学研究的重要工具,其量热体系之仪器常数的标定目前所广泛采用的方法是电能标定法,有时也采用化学标定法．前者简单、方便,能满足热静力学与热动力学研究中的需要,但电能标定所得仪器常数与化学反应时的仪器常数不一定完全相同［１］,特别是有些热...     

钨酸铅晶体抗辐射性能的测试

大型强子对撞机(LHC)运行时具有很高的辐射背景,为达到所要求的电磁量能器的测量精度对研制中的钨酸铅晶体的抗辐照性能提出了很高的要求.本文主要介绍了用⁶⁰Co的γ射线,在相应的辐照剂量率辐照下,对几种全尺寸(23cm长)钨酸铅晶体抗辐照性能的评估和测量方法.研究了晶体在侧面辐照条件下对光产额及纵向发光均匀性的影响,给出了对几种晶体的测量结果.