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1.
用批量法合成了聚苯乙烯(PSt)、聚甲基丙烯酸甲酯(PMMA)、聚丙烯酸丁酯(PBA)均聚乳液,以及P(BA-St)和P(BA-MMA)共聚乳液.实验发现极性相近的PBA和PMMA乳液可以很好地混合,而极性相差较大的PBA和PSt乳液则必须在PSt乳液中补加乳化剂后方能混合均匀.对乳液最低成膜温度(MFT)、胶膜硬度及耐水性的研究表明:质量比为11的PBA/PMMA共混胶膜和P(BA-MMA)共聚胶膜的连续相组成相近;而对于同样组成的PBA/PSt共混胶膜,分散在连续相中的PSt所占比例明显高于P(BA-St)共聚胶膜;PBA/PSt共混胶乳的使用性能不仅取决于其组成,还取决于成膜温度和使用温度  相似文献   

2.
使用热失重分析仪对TMP,PMP,TMPM,GW540,Tinuvin770等小分子型受阻胺光稳定剂、TMPM的均聚物PTMPM和PMPM的均聚物PPMPM、一系列具有不同单体配比的PDS,TMPM和PMPM分别与MMA,St,MAA,AA共聚得到的共聚物等受阻胺类光稳定剂进行了热失重分析(TG)。实验发现小分子型的受阻胺光稳定剂的热稳定性均较差,它们的热稳定顺序是TMP〈PMP〈TMPM〈GW5  相似文献   

3.
互穿聚合物网络的高分辨裂解色谱—质谱研究   总被引:4,自引:0,他引:4  
本文用高分辨裂解色谱-质谱法(HRPyGC—MS)研究了聚醚型聚氨酯/聚(苯乙烯-共-二乙烯苯)互穿聚合物网络[PU/P—co—DVB)—IPN]热分解过程的特征、裂解产物的组成和分布;IPN与其组分聚合物的裂解谱图比较表明,PU/P(St—co—DVB)是一种两网络间不存在化学结合的典型的互穿聚合物网络。由热失重曲线发现IPN材料有两个热分解阶段;从裂解产物的温度依赖性和分步裂解色谱分析并结合动态热重法结果讨论了其热分解机理。  相似文献   

4.
在热重分析系统上进行磁热重分析(MTGA),测量非晶FeSiB合金升温过程的比饱和磁化强度随温度变化σ-t曲线及(dσ/dt)-t曲线,它比DSC分析能更加明显的区分晶化过程的各个阶段,结果表明,样品升温过程经历了6个阶段的变化;并且发现,在晶化温度tx以下约150℃温区内等温退火的样品,居里温度tc随退火温度ta增大而升高,在430℃附近tc上升出现拐点。(dσ/dt)-t曲线的极小温度峰温tm  相似文献   

5.
关于P-内射环   总被引:3,自引:2,他引:1  
假定R和T均是环,M是(R,T)-双模且MT是忠实的,利用双模RMT来研究T的P-内射性,证明了如下结果:环T是右P-内射的当且仅当对于任意t∈T有Mt=((Mt)C)S和Tt=(Mt:M)T;环T是左P-内射的当且仅当对于任意t∈T有lM(t)=((lM(t))S)C和tT=rTlM(t).  相似文献   

6.
PMSQ/PVC(100/0,70/30,50/50,30/70,0/100)共混物由溶液浇法制备.经透射电镜观察到该共混物呈微观分相,但两相间界面较模糊;当PVC含量增至70%时,发生相逆转.所有共混物的扭辫曲线均只有唯一的玻璃化转变,并且由扭辫技术测得的PMSQ/PC共混物的Tg与由经验公式计算值相吻合,PMSQ、PVC在TBA测试尺度上的相容性较好.由于PMSQ中的SiOH在第一次升温中当温度高于318K时发生进一步交联反应,所有共混物二次加热后的Tg均比第一次升温时高,热历史对PMSQ/PVC共混物的Tg影响较大  相似文献   

7.
经刚果红实验、动态热流变测试、热重分析和扫描电镜等,研究了顺丁烯二酸二丁基锡酯(DBTM)-丙烯酸丁酯(BA)-苯乙烯(St)三元共聚物(PDSB)对聚氯乙烯(PVC)的热稳定作用.结果表明,在含锡量相同的条件下,PDSB对PVC的热稳定效果优于DBTM,还可以提高PVC的加工流动性.该研究是实现PVC有机锡热稳定剂高分子化和多功能化的探索之一.  相似文献   

8.
关于P—内射环   总被引:1,自引:0,他引:1  
假定R和T均是环,M是(R,T)-双模且MT是忠实的,利用双模RMT来研究T的P-内射性,证明了如下结果:环T是右P-内射的当且仅当对于任意t∈T有Mt=(Mt)^c)^s和Tt=(Mt:M)T;环T是左P-内射的当且仅当时于任意t∈T有lM(t)=((lM(t)^s)c和tT=rTlM(t)。  相似文献   

9.
醋酸乙烯酯与丙烯酸甲酯的种子乳液聚合   总被引:1,自引:0,他引:1  
以过硫酸铵(APS)为引发剂,对丙烯酸甲酯(MA)的乳液聚合进行了研究,得出在MA/H2O重量比为0.5时,60℃下合成粒径分布均匀的聚丙烯酸甲酯(PMA)种子乳液的最佳配方为:十二烷基硫酸钠(SDS)、(APS)和(NaHCO3)的浓度分别为11.6、1.72和4.69mmol/L.然后以PMA乳液为种子,以油溶性偶氮二异丁腈(AIBA)为引发剂,分别进行不溶胀与溶胀条件下醋酸乙烯酯(VA)的种子乳液聚合,并以磷钨酸为染色剂,用透射电子显微镜(TEM)对胶粒形态进行了表征  相似文献   

10.
PMSQ/PVC(100/0,70/30,50/50,30/70,0/100)共混物由溶液浇法制备。经透射电镜观察到该共混物呈微观分相,查两相间界面较模糊;当PVC含量增至70%时,发生相逆转。所有共混物的扭瓣曲线均只有唯一的玻璃化转变,并且由扭瓣技术测得的PMSQ/PC共混物的Tg与由经验公式计算值相吻合,PMSQ、PVC在TBA测试尺度上的相容性较好,由于PMSQ中的Si-OH在第一次升温中当  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 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   

13.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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