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991.
B. P. Liu X. C. Lv Z. C. Tan Z. H. Zhang Q. Shi L. N. Yang J. Xing L. X. Sun T. Zhang 《Journal of Thermal Analysis and Calorimetry》2007,89(1):283-287
The molar heat capacity, C
p,m, of a complex of holmium chloride coordinated with L-aspartic acid, Ho(Asp)Cl2·6H2O, was measured from 80 to 397 K with an automated adiabatic calorimeter. The thermodynamic functions H
T-H
298.15 and S
T-S
298.15 were derived from 80 to 395 K with temperature interval of 5 K. The thermal stability of the complex was investigated by
differential scanning calorimeter (DSC) and thermogravimetric (TG) technique, and the mechanism of thermal decomposing of
the complex was determined based on the structure and the thermal analysis experiment. 相似文献
992.
993.
X. P. Geng H. F. Zhang B. H. Wang X. D. Geng J. W. Xing 《Journal of Thermal Analysis and Calorimetry》2005,80(1):193-199
Summary Two hydrated and aged cement pastes from India (NCB), w/c=0.4, of a similar chemical composition but of a different specific surface and different strength (OPC, C-33 and C-43), hydrated at w/c=0.4 for 1 month, were studied by XRD after 1 year and 5-6 year ageing on contact with air. They were tested by static heating (SH) in fresh state, and by DTA/DTG/TG, IR and mass spectrometry (MS), after ageing, presented elsewhere. The main XRD peaks of (i) portlandite were decreasing with T and disappearing about 450°C, (ii) calcite peak at room T was small and broad, it increased gradually, especially after portlandite disappearance; above 600°C it was lowered and it was lost above 700°C. Important variation in the d(001) of portlandite with ageing was observed, exceeding the standard value of d(001)=4.895 Å (72-0156). It was higher in the paste C-33 (4.925-4.936 Å), containing more carbonates, than in the paste C-43 (4.916-4.927 Å). Small variations only were found in the value of d(101), i.e. 2.627-2.635 Å (nominally 2.622 Å), whereas the d(104) of calcite could be used as internal standard and other calcium carbonates (vaterite and aragonite) showed a small variation only. The increase ind(hkl) with temperature was straight linear (in portlandite d(001)=0.095 Å, at 30-400°C) and the thermal expansion coefficient estimated thereform was high (4.75-4.95·10-5 K-1). Close to the T of decomposition the d/T became steeper. The thermal variation of d(104)=3.035 Å of calcite (d=0.015 Å at 30-400°C) was smaller than that ofd(101) of portlandite (d=0.025 Å at 30-400°C) and was similar in C-33 and C-43. The thermal expansion coefficient was 1.54 10-5 K-1, thus higher than the reported a=0.65·10-5 K-1. 相似文献
994.
Oscillation criteria for PDE with p-Laplacian
div(|Du|p-2A(x)Du)+c(x)|u|p-2u=0\mbox{div}(|Du|^{p-2}A(x)Du)+c(x)|u|^{p-2}u=0 相似文献
995.
碱金属碳酸盐催化合成酚酞环氧树脂 总被引:1,自引:0,他引:1
在碱金属碳酸盐(K_2CO_3,Na_2CO_3)/H_2O催化下制备了低分子量酚酞环氧树脂.用IR、 ̄1HNMR表征了其分子结构,测定了树脂产物的环氧值E和数均分子风及分子量分布,讨论了单体的摩尔比,催化剂含量及水含量对产物的影响,结果表明,在实验范围内,改变酚酞与环氧氯丙烷的摩尔比(1:10~1:4)或酚酞与催化剂的摩尔比(1:2~1:1),均可以得到低分子量酚酞环氧树脂(500~700). 相似文献
996.
利用金属有机物化学气相沉积技术在蓝宝石衬底上低温生长GaN:Mg薄膜,对不同源流量的GaN:Mg材料特性进行优化研究.研究表明二茂镁(CP2Mg)和三甲基镓(TMGa)物质的量比([CP2Mg]/[TMGa])在1.4×10-3—2.5×10-3范围内,随[CP2Mg]/[TMGa]增加,晶体质量提高,空穴浓度线性增加.当[CP2Mg]/[TMGa]为2.5×10-3时获得空穴浓度与在较高温度生长获得的空穴浓度相当,且薄膜表面较粗糙.采用[CP2Mg]/[TMGa]为2.5×10-3的p型GaN层制备的发光二极管,在注入电流为20mA时,输出光强提高了17.2%. 相似文献
997.
998.
为了解碱度对絮体的形成、破碎及再生过程的影响,采用PDA2000型透光脉动检测仪测定不同碱度下投加硫酸铝时高岭土悬浮液的絮凝指数(FI指数),并以强度因子和再生因子评价絮体的强度和再生能力。结果表明,碱度的高低在很大程度上会影响絮体的形成、破碎及再生过程,所形成絮体的颗粒随碱度的增加而减小。混凝剂投量和碱度高低共同决定了絮体的抗破碎强度,碱度越高,混凝剂投量越大,絮体的强度越高。在电中和作用下形成的絮体在低碱度下经一次破碎后恢复程度接近100%,在网捕卷扫作用下形成的絮体,无论碱度高低,从第2次破碎起,FI指数均以大于10%的幅度逐次下降,絮体不可恢复程度显著增大。 相似文献
999.
<正>We presented a novel orthogonally linearly polarized Nd:YVO4 laser.Two pieces of a-cut grown-together composite YVO4/Nd:YVO4 crystals were placed in the resonant cavity with the c-axis of the two crystals orthogonally.The polarization and power performance of the orthogonally polarized laser were investigated.A 26.2-W orthogonally linearly polarized laser was obtained.The power ratio between the two orthogonally polarized lasers was varied with the pump power caused by the polarized mode coupling.The longitudinal modes competition and the corresponding variable optical beats were also observed from the orthogonally polarized laser.We also adjusted the crystals with their c-axis parallele to each other,and a 40.7-W linearly polarized TEMoo laser was obtained,and the beam quality factors were Mx2=1.37 and My2 =1.25. 相似文献
1000.
A sample preparation method for gas chromatography using a two-phase, laminar flow extraction PDMS/glass chip has been developed. A stable two-phase laminar interface was obtained by surface modification, and the organic extraction phase and the aqueous sample phase were separated effectively when the two-phase laminar flows exit the chip. Experiments were conducted on the chip to extract ephedrine from aqueous solution. Good reproducibility was obtained over the entire range of ephedrine concentration using the extraction chips (CV range 2.7%-4.5%). Effects of salt and solvent on extraction efficiency were studied. 相似文献
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