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1.
通过粘度、电导率、表面张力以及紫外吸收光谱等手段,研究水溶性中性聚合物聚乙烯醇(PVA)与阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)之间的相互作用。结果表明,PVA与CTAB之间有一定的相互作用,从而使体系表现出异常的粘度行为,显示出一定的电粘效应,并导致其混合溶液的最大紫外吸收峰发生了红移,未观察到PVA的加入对CTAB溶液表面张力和临界胶束浓度的影响。  相似文献   

2.
本文通过粘度和电导率的测定。研究了聚乙烯醇(PVA)与十二烷基硫酸钠(SDS)之间的相互作用以及无机盐NaCl对相互作用的影响,结果表明,PVA可与SDS分子结合形成复合物,从而使体系表现出典型聚电解质的粘度行为,而NaCl对体系粘度性质的影响与无机盐对聚电解质的影响类似.  相似文献   

3.
采用乌式粘度计对聚乙烯醇(PVA)水溶液的粘度进行了测定,发现如果以比浓粘度η sp/C对浓度作图,在极稀浓度区高分子溶液的粘度出现正的偏离.进一步的实验结果表明,由于受到乌式粘度计结构上的限制,目前广泛被采用的体积稀释法将不能用来确定极稀高分子溶液的粘度.文章在对极稀浓度区聚乙烯醇水溶液反常的粘度行为进行了合理解释的基础之上,提出了极稀高分子溶液粘度的测定方法.  相似文献   

4.
在聚乙烯醇(PVA)的醋酸乙烯酯(VAc),丙烯酸丁酯(BA)体系中,讨论了在无酸及顺丁烯二酸酐(MAn)、或丙烯酸(AA)、或α—甲基丙烯酸(MAA)的加入等四种情况下,所得乳胶粒径大小及分布、流变性、离心稳定性、膜的耐水性、剥离强度等性能的变化,所得数据表明,酸的加入使得乳胶体系的粒径变大,AA的加入使体系粘度增大,稳定性增强,MAn的加入使其乳胶对PVC塑料具有较强的粘接力。  相似文献   

5.
采用静电纺丝技术成功制备聚乙烯醇(PVA)/聚丙烯酸(PAA)/氧化石墨烯(GO)三元复合纤维材料,分别采用扫描电子显微镜(SEM)、傅立叶转换红外光谱(FT-IR)等技术对复合纤维材料的形貌及组分进行了表征。同时详细研究了制备过程中组分浓度、针头尺寸与加入量的最优条件。结果表明,PVA的浓度在8%~9%范围内能够单独纺丝形成均匀的纤维结构,加入PAA/GO混合溶液后,控制适当粘度即可电纺成丝且热处理后形成的纤维由水溶性转变为非水溶。本研究工作为静电纺丝复合纤维材料的设计与制备提供了有益的探索。  相似文献   

6.
采用粘度法测定了不同温度下 ( 2 98 1 5K ,30 8 1 5K ,31 8 1 5K)阴离子表面活性剂十二烷基硫酸钠 (SDS)—水溶性聚合物聚氧乙烯 (PEO)体系在有无电解质 (NaOH)存在时溶液的宏观粘度 ,研究了SDS—PEO体系分子间相互作用对PEO构型的影响 ,得到了不同SDS—PEO体系的临界聚集浓度 (CAC)和聚合物饱和浓度 (PSP) ,并根据表面活性剂—聚合物体系相互作用模型计算了SDS胶束被吸附到聚合物PEO过程的吉布斯函数变 ,讨论了SDS—PEO体系分子间相互作用强度 结果表明 ,在所研究范围内 ,SDS—PEO体系有无电解质溶液的比浓粘度均随聚合物PEO浓度的减小而急剧升高 ,呈现典型的聚合电解质行为 ,而且SDS的浓度越大 ,电粘效应愈明显 由此可以推断 ,聚合物PEO与表面活性剂SDS之间主要是通过疏水键相互结合 ,PEO分子链处于更伸展的状态 NaOH的存在使聚合物PEO分子与胶束结合位置减少 ,聚集体的体积减小 ,或者介电常数增大 ,因此表现出电粘效应弱于不含碱的表面活性剂—聚合物体系 ,而且使其分子间相互作用强度降低  相似文献   

7.
:通过测定混合体系粘度、紫外、红外及DSC谱图 ,研究了聚乙烯吡咯烷酮(PVP)与水解聚丙烯酰胺 (HPAM )之间的相互作用 .结果表明 ,PVP/HPAM混合体系的增比粘度比单一体系增比粘度的简单加和大得多 ,并且PVP的加入增大了HPAM的抗盐性 .光谱结果显示 ,在溶液中二者通过静电力可形成超分子复合物 .  相似文献   

8.
本文系采用蔗糖和甘油借以改变溶液的粘度,所测得溶液粘度对扩散电流的影响。根据Ilkovie公式和Stokes—Einstein关系式可得: i_d=K(1/η1/2)即扩散电流与溶液粘度的平方根成反比。实验结果表明,溶液粘度对扩散电流的影响极大。Cd~( )、Pb~( )、Zn~( )、Ni~( )离子在蔗糖溶液中,当溶液粘度在4.37(相对)以下时,所测得的i_dη1/2之值为接近常数,大于4.37时则i_dη1/2不成常数,这与Mckenzie的结果基本符合。在不同浓度的甘油溶液中(至50%左右),Cd~( )、Pb~( )、Ni~( )离子的i_dη1/2的值均接近常数。因此,同一待测物质,由于改变溶液粘度的物质不相同,对i_dη1/2之值有不同的影响。  相似文献   

9.
检测体系的紫外可见光谱、荧光光谱、表面张力、电导率等,研究了十二烷基硫酸钠(SDS)和盐酸普鲁卡因(PCN)与酸性形态中性红(NRa)的相互作用.中性红能降低SDS的临界胶束浓度.在SDS稀溶液中,表面活性剂分子能减弱NRa紫外吸收光谱及荧光发射光谱的强度.随着SDS溶液浓度的增大,NRa的光谱强度增大.NRa吸附于球状胶束表面,定位于棒状胶束膜相较深处.在SDS胶束体系中,随着PCN的加入,NRa的紫外可见光谱、荧光光谱强度减弱.  相似文献   

10.
采用高压静电纺丝技术制备了聚乙烯醇/壳聚糖(PVA/CS)的复合纳米纤维。通过扫描电子显微镜考察了纯聚乙烯醇PVA纤维和PVA/CS复合纳米纤维的形貌变化。研究表明,随着纺丝溶液浓度的不断增大,所得的纤维形貌越来越规则,纤维直径也逐渐变大。这种具有良好生物相容性的PVA/CS复合纳米纤维有望在生物医学方面得到应用。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

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