基于硬脂酸丁酯乳液的球形相变微胶囊的制备

采用三聚氰胺-甲醛树脂为壁材,硬脂酸丁酯为芯材,通过原位聚合法制备相变微胶囊.通过正交试验方法研究乳化剂用量、HLB值、乳化温度及乳化时间对硬脂酸丁酯乳液的影响,确定最佳乳化条件.采用激光粒径分布仪、FT-IR、SEM、DSC表征乳化液形貌、稳定性和相变微胶囊的结构、形貌以及热性能.结果表明:当复配乳化剂的HLB值=11,乳化时间为20min,乳化温度为70℃,乳化剂用量为10%,搅拌速度为4 000r/min,硬脂酸丁酯乳液的稳定性最好,以此乳液制备的微胶囊呈规则球状,结构致密,分散均匀,平均粒径3μm;相变温度为20.4℃,相变潜热为87.81J/g.     

微胶囊相变材料的制备与表征

以正十八烷为芯材、三聚氰胺-甲醛树脂为壁材,采用原位聚合法合成了相变储热微胶囊.利用光学显微镜、扫描电镜、差示扫描量热仪等对样品性能进行了分析和表征,并讨论了乳化剂种类和用量、助剂异氰酸酯等对微胶囊性能的影响.实验结果表明,采用阴离子与非离子混合乳化剂制备的微胶囊的各项性能均优于采用单一阴离子乳化剂所制得的微胶囊;助剂异氰酸酯的加入可大大提高微胶囊的相变潜热;所制备的相变储热微胶囊包裹完全,表面光洁,粒度均匀,平均粒径为4μm,相变潜热达176.5 J/g.     

微胶囊相变材料的原位聚合法合成与性能

采用RT31石蜡为芯材、脲醛树脂为壁材,利用原位聚合法制备相变材料微胶囊,采用扫描电子显微镜、差示扫描量热仪和光学显微镜考察了乳化剂种类对微胶囊微观形貌和热性能的影响,同时考察了不同乳化剂用量和乳化转速下制备的微胶囊的平均粒径及其分布和热性能,最后讨论了制备过程中不同酸化时间对微胶囊微观形貌的影响.实验结果表明:由52%的吐温60和48%的司盘60组成的复合乳化剂,其用量为芯材质量的5%、乳化转速为3000r/min时,制备的微胶囊呈现呈粒径均一、表面光滑、密封良好的球状,相变温度为303.10K,潜热最高达63.85J/g,平均粒径为9.32μm;在微胶囊的制备过程中,适宜的酸化时间为90min.     

原位聚合法制备微胶囊相变材料及其性能研究

本文通过原位聚合法制备了以脲醛树脂为壁材的微胶囊相变材料。采用SEM,DSC,光学显微镜等测试仪器考察了乳化剂种类、用量及乳化转速对微胶囊性能的影响;分析了助剂NaCl和分散剂NNO的用量对微胶囊微观形态、相变潜热和平均粒径的影响。实验结果表明,在乳化转速为3000rpm下,使用用量占芯材质量5%的复合乳化剂合成的微胶囊热性能良好,球体表面光滑,粒径均一。加入NaCl溶液后,微胶囊的相变潜热增加;当NaCl浓度为10%时,相变潜热达到最大,包覆率达到92.04%。同时加入占芯材质量2%的NNO,微胶囊的分散性好。     

尿素-三聚氰胺-甲醛树脂相变微胶囊的制备及性能

以尿素-三聚氰胺-甲醛树脂(UMF)为壁材,石蜡为芯材,通过原位聚合法制备了相变微胶囊,并探讨了尿素含量对相变微胶囊性能的影响。通过傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)、差示扫描量热分析(DSC)、热重分析(TG)及渗漏率对相变微胶囊进行表征。结果表明,与三聚氰胺-甲醛树脂(MF)相变微胶囊相比,UMF相变微胶囊的表面更光滑,破损率更低,热稳定性能更高。当尿素与三聚氰胺质量比为10%时,相变微胶囊的渗漏率最低。     

含香茅油的丙烯酸树脂基相变/抗菌复合微胶囊的制备及表征

以甲基丙烯酸甲酯-甲基丙烯酸共聚物为壁材,正十八烷和香茅油为芯材,季戊四醇四丙烯酸酯为交联剂,成功制备出了含有香茅油的相变/抗菌复合微胶囊。采用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)、差示扫描量热(DSC)和热重分析(TGA)等方法对以不同乳化剂种类及不同芯材比例制备的微胶囊的表面形貌、化学结构及热性能进行了分析和表征。试验结果表明:以阿拉伯树胶为乳化剂所制备的微胶囊表面形貌最好;香茅油的加入有利于微胶囊的包覆;当正十八烷与香茅油的质量比为3∶1时,微胶囊的热焓值为84.19J/g,并且具有良好的热稳定性;当微胶囊中香茅油的含量为18.75%时,微胶囊的抑菌率可达到62.79%。     

壳聚糖/马铃薯蛋白/山茶籽油微胶囊的研制

采用马铃薯蛋白(PP)、山茶籽油(CO)以及壳聚糖(CS)为主要原料,运用复合凝聚法通过乳化、冷冻干燥等制备出性质稳定的壳聚糖/马铃薯蛋白/山茶籽油微胶囊,通过考察微胶囊制备过程中乳液形成和复凝聚效果获得最佳制备条件.结果表明,壳聚糖/马铃薯蛋白/山茶籽油微胶囊的最佳制备条件如下:匀浆转速为8000 r/min,乳化时间为20 min,山茶籽油/马铃薯蛋白质量比为1:2,壁材的复合凝聚比(PP/CS)为2:1,温度为45℃.通过结构与性质表征发现,马铃薯蛋白基微胶囊壁材成功包裹芯材山茶籽油,在马铃薯蛋白及功能性油脂的高值化利用中具有广阔的应用前景.     

原位聚合法制备甲维盐微胶囊的研究

采用原位聚合法制备以脲醛树脂为壁材的甲维盐微胶囊制剂.研究了壁材与芯材的比例、分散乳化剂、催化剂、反应温度和搅拌速度5因素对微胶囊产品的影响,得出最优化的工艺为:壁材与芯材的比例为m(壁材)∶m(芯材)=8.0∶2.0,以聚丙烯酸钠为分散乳化剂,氯化铵为酸性催化剂,加入速度以2h加完,终点pH值为2.0,缩聚反应温度控制在70℃左右,反应时间为3h,搅拌速度为1000r/min.结果表明以此获得的产品具有良好的缓释效果.     

基于非离子复合乳化剂自修复微胶囊的制备

提出采用低起泡性的OP-10/AEO非离子复合乳化体系解决微胶囊制备过程中乳化缺陷问题。以改性环氧树脂E-51为芯材修复剂,通过原位聚合法制备脲醛树脂自修复微胶囊。采用光学显微镜、傅里叶红外光谱仪、同步热分析仪分别对形成过程、化学结构及热稳定性进行分析。利用Gauss拟合研究粒径分布,并探讨了乳化剂体系选择、乳化剂用量、芯壁比、搅拌速率等因素对微胶囊性能的影响。结果表明,该体系能有效改善乳化剂起泡效果,用量为5.0%,芯壁比为0.8∶1,搅拌速率为1 200 r/min,微胶囊包封率达到80%,粒径分布相对集中,具备良好的室温贮存性及热稳定性。     

基于三聚氰胺-甲醛树脂包裹十二醇微胶囊相变材料的工艺控制过程研究

目的研究微胶囊制备造壁工艺控制过程。方法以三聚氰胺-甲醛树脂为壁材,正十二醇为芯材,采用原位聚合法对芯材十二醇进行包囊,制备微胶囊相变材料。考察了微胶囊制备造壁工艺中pH、温度、时间、预聚物滴加速度、乙酸滴加速度及升温速度对微胶囊包封率的影响。结果工艺条件为pH 4.5～5.5、温度60～80℃、时间120～140min,乙酸(体积分数,10%)滴加速度为1.0 mL/min、升温速度为3℃/min和预聚物滴加速度为1.0 mL/min时,包封率达58.0%。结论形成的微胶囊呈球形,规则性好,结构致密,且包封率高。     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Design and analysis of generic LBS application developing platform

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that