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1.
壳聚糖半稀溶液性质的研究   总被引:1,自引:0,他引:1  
研究了壳聚糖乙酸半稀溶液的性质,结果表明,壳聚糖乙酸半稀溶液的零粘度η0随乙酸含量的增加,壳聚糖含量的减少,温度的升高,放置时间的延长而减小,流动活化能ΔEq和结构粘度指数Δη随壳聚糖含量的增加、乙酸含量的减少而增大,在溶液中添加NaCl将使溶液粘粘大,添加脲将使溶液粘度减小,溶液的稳定性随放置时间的延长而降低,NaCl和脲对溶液稳定性的影响不明显。  相似文献   

2.
纤维素在磷酸/多聚磷酸复合溶剂中的溶解性能   总被引:1,自引:0,他引:1  
通过捏合机制备了纤维素在磷酸/多聚磷酸复合溶剂中的液晶溶液.主要研究纤维素质量分数、温度、复合溶剂中P2O5质量分数对纤雏素一磷酸/多聚磷酸溶液性能及溶解行为的影响.结果表明,液晶溶液的清亮点随P2Os质量分数及纤维素质量分数的增加而升高.溶解时间随P2O5质量分数的升高及温度的降低而增加.在此基础上,分析了磷酸/多聚磷酸溶剂与纤维素的相互作用并提出了纤维素在磷酸/多聚磷酸溶剂中的溶解过程及机理.  相似文献   

3.
壳聚糖溶液性质的研究   总被引:8,自引:0,他引:8  
将壳聚糖分别以甲酸、乙酸、盐酸和甲酸/乙酸混合液为溶剂,配制成一定的浓度, 溶液粘度随壳聚糖浓度、存放时间、温度以及溶剂体系的变化情况。实验表明,溶液粘度随壳聚糖浓度的增加而增大,随存放时间延长和温度升高而降低,随溶剂中酸浓度增加和酸性增强而下降  相似文献   

4.
刘让同  李亮 《科学技术与工程》2013,13(21):6317-6322
采用AR—1500ex流变仪对不同质量分数海藻酸钠溶液的流变性能进行研究,探讨了溶液流变性的浓度依赖性问题。结果表明,非牛顿指数随海藻酸钠溶液质量浓度的增加而下降,表观黏度、动态黏度、稠度系数、结构黏度指数、黏流活化能随其质量浓度的增加而呈上升的趋势;损耗模量和贮能模量随频率的增加而增加,随温度的升高而下降;损耗因子和动态黏度随频率的增加而呈下降的趋势。  相似文献   

5.
研究了两组分的共聚酯PECT(聚对苯二甲酸乙二醇-1,4-环己基二甲醇酯)的流变性能。结果表明,ETCT共聚酯的熔体属于非牛顿流体,呈现典型的切力变稀行为。共聚酯的剪切应力随剪切速率的提高而增加,随着温度的提高,剪切应力有所下降。共聚酯熔体粘度随CT链段的引入及含量的增加而上升,同时也随温度的升高而降低。共聚酯熔体的粘流活化能均大于常规PET,加入第二组份的量越大,共聚酯粘流活化能、表观粘度上升越明显。共聚酯熔体的非牛顿指数n值均低于常规PET,且随温度的升高而增大。考查温度和剪切速率等流变参数对共聚酯流变性能的影响,可以在加工过程中合理地控制工艺,对工艺条件的设定有很好的指导作用。  相似文献   

6.
本文研究了不同氯化钠(NaCl)浓度,不同温度下的海藻酸钠(SA)及其与多壁碳纳米管(MWCNTs)复合溶液的流变行为。利用 Ostwald’s 和 Arrhenius 方程计算得出溶液的非牛顿指数和粘流活化能。结果表明,纺丝溶液属于非牛顿流体,溶液的零剪切粘度随着NaCl浓度的增加逐渐增加,非牛顿指数却逐渐降低。MWCNTs 的加入使得SA溶液的粘流活化能降低,说明 MWCNTs 的加入增加了溶液的流动性。  相似文献   

7.
溴化锂对NH3-H2O-LiBr三元溶液特性作用机理的初步研究   总被引:1,自引:1,他引:0  
针对目前吸收式制冷领域中研究的NH3-H2O-LiBr三元溶液混合工质,采用溶剂化作用模型和电解质NRTL方程,研究了溴化锂(LiBr)对溶液组成的影响.结果表明:随着LiBr初始摩尔分数的升高,水的溶剂化系数m先升高,后略有降低,氨的溶济化系数n始终呈下降趋势,并且在350 K、LiBr的初始摩尔分数大于0.03时m>n,离子溶剂化作用形成的离子簇包含的水分子多于氨分子;溶剂化作用后水的含量高于作用前的,但前后差值随LiBr初始摩尔分数升高而减小;随着温度的升高,m 降低,n 升高,离子吸引水分子的能力减弱而吸引氨分子的能力升高;完全电离的溶剂化模型只在LiBr的初始摩尔分数小于0.1时得到较好的结果,在LiBr的初始摩尔分数大于0.1时与部分电离模型产生较大的误差.  相似文献   

8.
使用带激光检测系统的实验设备,动态法测定了没食子酸在一系列乙醇+水混合溶剂中,温度范围为283~323K间的溶解度。分别采用Apelblat方程和Jouyban-Acree模型对实验数据进行了关联,关联结果的平均相对误差分别为0.63%和10.84%,Apelblat方程相比Jouyban-Acree模型能够更好的关联实验数据。没食子酸在不同配比的乙醇+水混合溶剂中溶解度均随温度升高而增大,随乙醇质量分数升高而增大,在乙醇质量分数为0.900的混合溶剂中有最大的溶解度。  相似文献   

9.
采用LiCl/DMAc溶解间位芳纶纤维,以H2O/DMAc为凝固浴,研究了凝固剂H2O与溶剂DMAc配比、LiCl质量分数和温度对间位芳纶溶液凝固性能的影响,并计算了凝固浴在芳纶溶液中的扩散系数.结果显示:凝固值随凝固浴中H2O含量的增大而逐渐减小,临界浓度则几乎没有变化;凝固值随芳纶溶液温度和LiCl质量分数的升高不断增大,而临界浓度则不断减小;凝固浴在芳纶溶液中的扩散系数随芳纶溶液质量分数的增大而减小,随凝固浴中凝固剂H2O含量的增大而增大.  相似文献   

10.
不同温度下煤在溶剂中的溶胀行为   总被引:8,自引:0,他引:8  
溶胀是煤直接液化升温过程中粘度发生变化的主要原因之一。本文研究了不同温度下两种煤在有机溶剂中的溶胀度变化。结果表明:在极性溶剂中,煤化程度较小的神华煤的溶胀性比新庄煤大,而在非极性溶剂四氢萘中,情况相反;温度升高加快了煤的溶胀速率,且对煤的溶胀度大小有影响;煤的溶胀度与煤和溶剂的溶解度参数有关,溶剂对煤的溶解能力越大,则煤在该溶剂中的溶胀度越大。  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.
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   

20.
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   

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