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31.
十二烷基苯磺酸钠水溶液聚集性质的研究 总被引:8,自引:0,他引:8
用滴体积法测出十二烷基苯磺酸钠(SDBS)稀水溶液的表面张力;然后求出其临界胶束浓度(CMC)。同时通过溶液的电导率、吸收光谱以及荧光光谱测定求出其CMC。这样测出的CMC值为1.2~1.6×10-3mol/L,与文献值相符。也研究了部分水解的聚丙烯酰胺(PHPAM)对SDBS聚集性质的影响;发现SDBS的CMC值随PHPAM的加人而减少并且PHPAM水溶液的粘度随SDBS的存在而急剧降低(类似盐效应)。这些方法与性质对强化采油(EOR)是重要的。 相似文献
32.
T. F Al-Fariss H. O. Ozbelge S. S. E. H Elnashaie S. M. AbdulRazik F. A. Abdel Aleem N. Gassem 《Nutrient Cycling in Agroecosystems》1991,28(2):201-212
This paper represents the first published report of a preliminary investigation of the possibility of using Saudi phosphate ores for the production of wet-process phosphoric acid. 相似文献
33.
为探讨厌氧系统降解五氯酚(PCP)能力及PCP对厌氧系统的毒性影响,采用UASB反应器进行了PCP模拟污水连续流试验,考察了不同PCP浓度及负荷条件下系统对PCP和COD的降解去除规律,揭示了PCP对系统产酸相和产甲烷相影响状况.结果表明,在进水PCP含量从无到开始加入、PCP浓度提高以及PCP负荷提高3个冲击变化阶段,厌氧系统对PCP和COD的去除率均表现出先迅速降低后缓慢升高的变化趋势,运行稳定后PCP和COD的去除率分别达91.2%和83.5%以上.PCP对厌氧系统中微生物种群产生影响,使系统产酸菌由丁酸型菌群为主逐渐演替为丙酸型菌群为主,PCP对系统产甲烷菌活性产生明显抑制,甲烷产量由PCP加入前的12.1L/d降低至加入后的2.5L/d. 相似文献
34.
This study aims to add to the discussion about the applicability of the classical deindividuation theory and social identity model of deindividuation effects (SIDE) in explaining online behaviours. It explores the effect of anonymity in facilitating social influence of group identity in online game cheating. A nationally representative survey was conducted face to face. Results from the survey administered in Singapore confirm predictions derived from the SIDE and challenge the classical deindividuation theory. Specifically, it was concluded that the frequency of gaming with online strangers (anonymous gaming) significantly predicted the frequency of cheating in online games. The effect of anonymity on game cheating was found to be significantly mediated by the group identification with online gaming communities/groups. Gender differences were found. Male gamers cheated more frequently than female gamers. Female gamers are more likely to cheat as a consequence of group identification than male gamers. Implications and future research are discussed. 相似文献
35.
提出一种基于小世界网络的自适应拓扑结构。每个粒子都与它的近邻粒子进行交互,其有一定概率通过小世界重置与远方的粒子进行沟通;为粒子群体的每个维度分配一个特定的小世界网络,不同维能够学习不同邻居的历史信息;粒子的邻域大小与小世界重置的概率将在种群收敛状态的基础上进行自适应调整。利用标准函数集对该算法进行测试,测试结果表明,通过该机制,粒子群体具有更好的搜索多样性,能够平衡全局探索与局部开发。 相似文献
36.
37.
In a previous paper, we described a procedure to correct the directional effects in AVHRR reflectance time series. The corrected measurements show much less high frequency variability than their original counterparts, which makes them suitable to study vegetation dynamics. The time series are used here to estimate the start and ending dates of the growing season for 18 years from 1982 to 1999. We focus on the interannual variations of these phenological parameters.A database of in situ phenology observations is used to quantify the accuracy of the satellite-based estimates. Although based on a limited sampling of the Northern mid and high latitudes, the comparison indicates that i) the satellite phenological product contains meaningful information on interannual onset anomalies; ii) there is a higher degree of consistency over regions covered by Broadleaf Forests, Grasses and cereal Crops than over those covered by Needleleaf Forests or Savannas; and iii) the satellite phenological product is of lower quality in regions with mountainous terrain. In favorable conditions, interannual variations of the onset are captured with an accuracy of a few days.As this satellite-derived product captures the interannual onset variability at ground-truth sites, we confidently use it to larger scales studies. Mapped at a continental scale, the onset anomalies show coherent patterns at the regional (≈ 1000 km) scale for the mid and high latitudes of the Northern hemisphere, which is consistent with a meteorological forcing. In the tropics, there is larger spatial heterogeneity, which suggests more complex controls of the phenology. The relation between vegetation phenology and climate is further investigated over Europe by comparing the variability of the satellite-derived vegetation onset and that of the winter North Atlantic Oscillation index, at a fine spatial scale. The strong correlations observed confirm that this climate forcing parameter explains most of the onset variability over a large fraction of Northern Europe (earlier onsets for positive winter NAO), with lower impact towards the south and opposite effects around the Mediterranean basin. The NAO has a predictive character as the January-February NAO index is strongly correlated with the vegetation onset that occurs around April in Northern Europe. 相似文献
38.
Vimal Singh 《Automatica》2008,44(1):282-285
A novel criterion for the global asymptotic stability of a class of digital filters utilizing single saturation nonlinearity is presented. An example showing the effectiveness of the present criterion is given. 相似文献
39.
A. Z. Panagiotopoulos 《International Journal of Thermophysics》1994,15(6):1057-1072
Abstact The subject of this paper is the investigation of finite-size effects and the determination of critical parameters for a class of truncated Lennard-Jones potentials. Despite significant recent progress in our ability to model phase equilibria in multicomponent mixtures from direct molecular simulations, the accurate determination of critical parameters remains a difficult problem. Gibbs ensemble Monte Carlo simulations with systems of controlled linear system size are used to obtain the phase behavior in the near-critical region for two- and three dimensional Lennard-Jones fluids with reduced cutoff radii of 3, 3.5, and 5. For the two-dimensional systems, crossover of the effective exponent for the width of the coexistence curve from mean field ( = 1/2 in the immediate vicinity of the critical point to Ising-like (= 1/8) farther away is observed. Critical parameters determined by fitting the data that follow Ising-like behavior are in good agreement with literature values obtained with finite-size scaling methods. For the three-dimensional systems, no crossover to mean field-type behavior was apparent. Extrapolated results for the critical parameters are consistent with literature estimates for similar fluids. For both two- and three-dimensional fluids, system size effects on the coexistence curves away from the critical point are small, normally within simulation statistical uncertainties.Invited paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder. Colorado, U.S.A. 相似文献
40.
We have investigated the dynamic behavior of a nonionic micellar solution of tetra-ethylene glycoln-decylether (C10 E4) in water near its critical point in the presence of shear. The non-Newtonian behavior of the viscosity can be represented by * = [ 1 +a(S4)=]2, where* is the viscosity in the absence of shear,S is the shear rate. 4 is the lifetime of the critical Iluctuations,a is a system-dependent constant, and = 0.02 In addition, we have found that, before attaining a steady state, the sheared mixture undergoing phase separation shows significant shear-dependent rheological effects due to the presence of concentration domains.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24. 1994, Boulder, Colorado, U.S.A. 相似文献