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1.
采用种子乳液聚合的方法合成了核壳结构的poly(methyl methacrylate)/polystyrene(PMMA/PS)和poly(butyl acrylate)/polystyrene(PBA/PS)微球,并以此作为前驱体,利用酸碱溶胀法成功地制备出PS中空微球.采用TEM和SEM对核壳微球和中空微球的形貌进行了表征,并研究了中空结构形成的影响因素.结果表明,在壳层单体St包裹种子微球的聚合阶段,单体和引发剂的滴加速度及温度对最终的PS中空微球形态有着显著的影响:滴加速度过慢,反应温度过高均不利于中空微球的形成.另外,组成种子微球的单体和壳层单体的性质对中空微球的形态也有着较大的影响.  相似文献   

2.
通过种子乳液聚合法制备得到亲水核与核壳结构微球,采用酸碱溶胀法处理核壳微球,制备了微米级中空微球。扫描电子显微镜、透射电子显微镜等测试分析表明,单分散性的亲水核平均直径约465 nm;单分散的核壳微球表面略显粗糙,平均直径约560 nm,疏水壳层厚度约100 nm;微米级中空微球的直径约1.20μm,中空度为21.6%,其单分散性与球形度良好。在亲水核聚合过程中,当m(MMA)/m(MAA)=1.771时,乳液反应体系稳定,得到亲水核微球的单分散性最好。  相似文献   

3.
以十六烷基三甲基溴化铵(CTAB)和十二烷基硫酸钠(SDS)分子自组装形成的囊泡为模板, 用氨水溶液提供缓冲环境, 甲阶酚醛树脂为前驱体, 控制表面活性剂配比, 反应温度和时间不变, 通过改变搅拌速率得到纳米/微米级酚醛树脂多层中空球, 并利用X射线衍射仪(XRD)、 透射电子显微镜(TEM)、 扫描电子显微镜(SEM)、 比表面积和孔隙分析仪、 热重分析仪(TGA)对所得微球进行表征. 结果表明: 酚醛树脂中空纳米球的粒径为50~60 nm, 球壳厚度约为10 nm; 酚醛树脂中空微米球分为单室和多室两种形貌, 单室中空球粒径为2~5 μm, 多室中空球粒径可达10 μm, 球壳厚度约为500 nm; 两种形貌的酚醛树脂中空球的球壳均为多层周期结构.  相似文献   

4.
以十六烷基三甲基溴化铵(CTAB)和十二烷基硫酸钠(SDS)分子自组装形成的囊泡为模板, 用氨水溶液提供缓冲环境, 甲阶酚醛树脂为前驱体, 控制表面活性剂配比, 反应温度和时间不变, 通过改变搅拌速率得到纳米/微米级酚醛树脂多层中空球, 并利用X射线衍射仪(XRD)、 透射电子显微镜(TEM)、 扫描电子显微镜(SEM)、 比表面积和孔隙分析仪、 热重分析仪(TGA)对所得微球进行表征. 结果表明: 酚醛树脂中空纳米球的粒径为50~60 nm, 球壳厚度约为10 nm; 酚醛树脂中空微米球分为单室和多室两种形貌, 单室中空球粒径为2~5 μm, 多室中空球粒径可达10 μm, 球壳厚度约为500 nm; 两种形貌的酚醛树脂中空球的球壳均为多层周期结构.  相似文献   

5.
摘要:采用磺化聚苯乙烯(Ps)微球为模板制备出了以Fe304-PANi(聚苯胺)为壳,PS为核的具有核壳结构多功能Fe304.PANi/PS复合微球.采用溶剂抽提溶解去除Ps核得到Fe304.PANi具有导电导磁双功能中空微球.中空微球空腔尺寸大小一致,约为190nm,壳层厚度约30nm.通过控制Ps模板磺化时间来同步控制微球空腔大小和微球壳层厚度.Fe304-PANi/PS复合微球及中空微球具有良好的导电性和超顺磁性.所制备的中空Fe304微球及中空Fe304-PANi微球对模拟污水浊度去除率分别达到84.2%及86.9%.  相似文献   

6.
利用W_1/O/W_2双重乳液法制备环氧树脂中空微球。研究了内水相(W_1)质量分数、外水相(W_2)温度及环氧预聚合时间等重要工艺参数对环氧树脂中空微球形貌的影响。通过扫描电子显微镜、激光粒度测试、红外光谱和热失重分析对环氧树脂中空微球进行了表征。结果表明:制备的环氧树脂中空微球具有较好的中空结构,其粒径约20μm,壁厚约5μm;粒径分布范围为10~100μm,体积加权平均粒径为35. 7μm;红外光谱结果表明所制备的环氧树脂中空微球固化较完全;热失重结果表明环氧树脂中空微球的热分解起始温度为316℃,质量保存率为15%。  相似文献   

7.
使用商业化的金属磷酸盐(M-P-O,M=Mg,Al,Ca,Fe,Co,Zn,La)为载体,以Pd(NO_3)_2为PdOx的前躯体,制备了PdOx/M-P-O系列催化剂,并测试了催化剂的N_2O分解性能.发现PdOx/Ca-P-O(又记为PdOx/HAP,HAP为羟基磷灰石)在该系列样品中表现出最佳催化活性,在反应温度375℃时能催化N_2O完全转化.而其他PdOx/M-P-O催化剂几乎没有活性.O2在反应气中的共存对PdOx/HAP的活性影响很小,而H_2O蒸气的共存明显抑制活性.但O2和H_2O蒸气对活性的影响是可逆的,即O2或者H_2O撤走后,活性复原.PdOx/HAP在无O2和有O2情况下都保持较好的稳定性.使用4%H2,在400℃对PdOx/HAP进行预处理能提高催化活性.使用XRD、TEM、XPS、ICP等对PdOx/HAP进行了表征.  相似文献   

8.
通过模板法制备中空SiO2/Fe3O4磁性微球,采用分散聚合法制备了大尺寸的聚苯乙烯微球作为模板,以界面沉积法制备了Fe3O4/PS复合粒子,溶胶凝胶法制备SiO2/Fe3O4/PS微球;经过高温煅烧使模板聚苯乙烯分解,得到中空磁性微球.通过透射电子显微镜、红外光谱仪、扫描电子显微镜、X射线衍射仪、震荡样品磁强计、物理吸附仪等仪器对中空SiO2/Fe3O4磁性微球进行了形貌和性能表征.结果表明:所制备的中空SiO2/Fe3O4磁性微球尺寸在700nm左右,大小均匀,有良好的分散性,并且中空磁性微球表面有孔,其孔径在16nm左右,具有较大的比表面积和孔容量.  相似文献   

9.
通过牺牲微米级PS模板原位合成方法制备微米级单分散中空SiO_2微球,着重研究反应温度(50,70℃)、TEOS用量(2,3,4 g)、氨水用量(1,2,3 mL)与MTC用量(0.2,0.4 g)等参数对中空微球的影响,获得微米级(1~5μm)、结构(孔径、壁厚等)可控的单分散中空SiO_2微球的最佳制备工艺,通过扫描电镜分析(SEM)、透射电镜分析(TEM)、红外光谱分析(FT-IR)、热失重分析(TGA)、氮吸附(BET)等测试手段表征了微球性能。  相似文献   

10.
玻璃基骨水泥生物活性的研究   总被引:3,自引:0,他引:3  
以CaO SiO2 P2 O5系统生物玻璃和磷酸铵调和液混合制得玻璃基生物骨水泥 (GBC) ,利用X 衍射 (XRD)、扫描电镜 (SEM )和红外光谱 (FTIR)对产物的晶相、化学组成和显微结构进行了分析 .结果表明 ,随着浸泡时间的增加 ,玻璃基骨水泥 (GBC)中的玻璃相逐步向类骨状羟基磷灰石 (HAP)微晶转化 ,所生成的HAP晶体端面尺寸分布在 30~ 5 0nm之间 ,这表明GBC中所生成的HAP晶体与人体骨中生物HAP很相似 ,会具有良好的生物活性 .FTIR的结果表明 ,CO2 -3 会部分地进入到HAP的晶格结构中 ,形成碳酸羟基磷灰石 .GBC中所生成的HAP晶体在形貌、结构和组成等多方面均与人体骨类似 ,有利于作为生物医用材料的应用 .  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.
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   

13.
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   

14.
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   

15.
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   

16.
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   

17.
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   

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.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
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