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91.
直接紫外法测定混合表面活性剂的临界胶束浓度 总被引:3,自引:0,他引:3
吴丹 《理化检验(化学分册)》1998,34(3):123-123,125
临界胶束浓度(C.M.C.)是表征表面活性剂性质的重要指标之一,是决定表面活性剂用量的依据。近年来,由于混合表面活性剂的协同增效作用,混合表面活性剂已被广泛用于生产和分析中,而其C.M.C.值报道较少。本文对工业生产和分析测试中常用的十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)、十六烷基三甲基溴化铵(CTMAB)、十二烷基二甲基苄基氯化铵(DDMBAC)与辛基酚 相似文献
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α,α-dimethoxy-α-Phenyl acetophenone (DMPA) is an efficient and thermally stable photoinitiator. Here its spectral characteristics in the transient state were shown. The transient species were identified as a benzoyl radical and a dimethoxyi benzyl radical that played a primary initiation role in polymerization. The kinetics and mechanism of the bulk polymerization of MMA were investigated. The exponent of DMPA concentration and k_p/k_1~(1/2) value were found to be 0.5 and 0.066 mol(-1/2)l~(1/2)s~(-1/2), respectively. The existence of oxygen led to obtain the polymer with higher molecular weight, which can be attributed to the occurrence of the subsequent polymerization induced by active polymer end group. In the photocrosslinking reaction, the dependence of DMPA content on initial rate has been found. A principal reason is that the sample contained higher percentage of DMPA has higher light-absorbed efficiency. In solid film, higher concentration of DMPA is permitted to be used because there is little excited state self-quenching effect in the rigid medium. 相似文献
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Jefferson Zhe Liu 《Acta Mechanica Sinica》2012,28(4):978-982
Reported values(0.2 MPa-7.0 GPa) of the interlayer shear strength(ISS) of graphite are very dispersed.The main challenge to obtain a reliable value of the ISS using conventional measuring methods was the unavailability of sufficiently large single crystalline graphite.Here we present a novel experimental method to measure the ISS,and obtain the value as ~0.14 GPa.Our result can serve as an important basis for understanding mechanical behavior of graphite or graphene-based materials. 相似文献
97.
Hong Shuai Dai 《数学学报(英文版)》2013,29(4):777-788
In this paper, we extend the well-studied fractional Brownian motion of Riemann-Liouville type to the multivariate case, and the corresponding processes are called operator fractional Brownian motions of Riemann-Liouville type. We also provide two results on approximation to operator fractional Brownian motions of Riemann-Liouville type. The first approximation is based on a Poisson process, and the second one is based on a sequence of I.I.D. random variables. 相似文献
98.
随着网络视频应用的飞速发展,达芬奇技术作为一种新平台逐渐成为数字视频技术应用的发展方向.针对网络视频传输实时性要求高的特点,本文提出了基于达芬奇技术的数字视频综合实验设计方案,TMS320DM6467平台具有ARM+DSP双核处理器,能够提高系统性能,缩短开发周期;DSP内核视频数据编码算法选用H.264,大大提高了数据编码效率;ARM核负责控制视频采集以及实时传输通信,便于学生对数字视频应用前沿技术进行探索. 相似文献
99.
高清视频数据量大给视频传输和存储带来困难,单纯增大带宽和存储容量已不现实。依据H.264视频压缩标准原理和TI高性能Davinci处理器特性,设计了基于DM6467的DSP(/ARM)+FPGA架构的高清视频压缩实时显示和存储硬件平台,并给出了H.264压缩算法实现方法。通过对视频序列进行验证,仿真结果表明,在峰值信噪比较高时,仍能得到约20倍的压缩比,同时具有良好的实时性。 相似文献
100.
Combined effect of modified zeolite 13X and β-nucleating agent on improving β-crystal content and toughening polypropylene random copolymer 总被引:1,自引:0,他引:1
Although addition of β-NUCLEATING agent directly into homo-polypropylene(PPH) is a useful method to improve β-CRYSTAL content and toughen PPH, polypropylene random copolymer(PPR) makes this method powerless due to its random structure and low crystallinity. In this study, the-nucleated PPR with high β-CRYSTAL content was prepared by a novel high effective β-NUCLEATING system which consists of-nucleation agent(TMB-5) and modified zeolite 13X(M13X). It was found that M13X and TMB-5 had a synergistic influence on improving β-CRYSTAL content and toughening PPR. The content of β-CRYSTAL in PPR/M13X/TMB-5 was significantly larger than the sum of that in PPR/M13X and PPR/TMB-5. Besides,fracture behavior, phase morphology and relaxation of matrix chain segments were also investigated. The results showed that M13X and TMB-5 improved the mobility of amorphous chain segments at low temperature and contributed to much energy dissipation. This work provides a powerful method to modify PPR. 相似文献