关于芦荟化学组成的探讨

本文提出了制取芦荟各类原汁的方法,并初步证实了芦荟大黄素类、芦荟苦素类和芦荟宁的存在及分布趋势。从而指出:凝胶原汁应用于日化产品将是最主要的开发方向之一。     

芦荟凝胶浴用香波设计及其抗氧化性能研究

通过提取库拉索芦荟凝胶原汁与几种表面活性剂进行互配,研制出一款具有抗氧化性的浴用香波.按冷、热稳定性以及发泡性等指标对设计出的香波进行初步筛选获得基础配方,然后对其所包含的几种表面活性剂进行正交实验设计,按上述相同指标筛选,找出最佳产品配方.再往最佳配方中添加芦荟凝胶原汁,通过紫外可见分光光度法测定添加芦荟凝胶原汁后的香波对DPPH·自由基的清除率,考察其抗氧化效果,并对国家轻工业标准规定的相关指标及性能进行检测.实验结果表明:实验所得最优配方中各表面活性剂之间具有较好的配伍性能,经过24 h冷、热稳定性测试,未发现变色以及分层的现象;当芦荟凝胶原汁的添加量为10%时,所制的浴用香波的DPPH·自由基的清除率约为47.25%,是未加芦荟凝胶原汁的6.85倍,说明其具有良好的抗氧化性;经理化指标检测得出其pH值为7.13;通过改进型罗氏泡沫仪测定其泡沫体积为495.24 mL;有效物含量为32.68%;经过48 h的微生物检测,结果均符合国家标准.     

芦荟凝胶原汁稳定性的研究

芦荟凝胶原汁含有多种生物活性成分,该原汁体系不稳定,易变质.本文提出的稳定方法,不仅可以满足在一个较长时间內原汁所含各种活性成分不变,也符合对人体无腐蚀、无刺激及其他副作用的要求,故可广泛应用于药物、食品、饮料及化妆品中. 本文比较了树状与斑纹二个不同品种的芦荟凝胶原汁后,得出了斑纹芦荟具有较高经济开发价值的结论.     

芦荟在化妆品中保湿性的研究

将芦荟作为添加物制成非乳化体系及乳化体系的芦荟化妆品.在不同的芦荟添加量、不同的温度及湿度环境中,与空白样、常用甘油保湿剂体系的保湿效果进行比较,通过实验测定失水率,获得芦荟在化妆品中保湿效果评价.实验表明,芦荟原汁应用在化妆品非乳化体系中的最佳百分数是40%～60%,在乳化体系中最佳百分数是40%～50%,并且优于5%甘油,从而得到芦荟是性能优异的保湿剂的结论.     

库拉索芦荟和木立芦荟叶的形态结构及有效成分含量的比较

应用植物解剖学和植物化学相结合的方法比较研究了3年生库拉索芦荟(Aloe vera L.)和木立芦荟(Aloe arborescens Mill)的形态结构和芦荟素、芦荟多糖等有效成分的含量.研究结果表明:(1)库拉索芦荟茎极短,叶丛生,成熟叶片长60~80 cm,质量400~550 g;木立芦荟茎高50~70 cm,叶互生,成熟叶片长40~50 cm,质量100~150 g.(2)两种芦荟叶都由表皮、同化组织、贮水组织和维管束组成.库拉索芦荟叶的贮水组织占横切面的90%以上,而木立芦荟叶的贮水组织仅占横切面的70%.(3)库拉索芦荟叶中芦荟素含量为1.46%,芦荟多糖含量为3.56%,宜作为芦荟多糖的原料;木立芦荟叶中芦荟素含量为2.15%,芦荟多糖含量为2.58%,宜作为芦荟素等蒽醌类物质的原料.研究结果为芦荟的引种栽培、采收和产品加工提供了科学依据.     

芦荟苷在水中稳定性的研究

采用高效液相色谱法,研究了时间、温度、pH、金属离子等因素对水溶液中芦荟苷稳定性的影响.结果表明,芦荟苷在水中不稳定,室温放置6d后其含量下降90.5%.温度和pH对芦荟苷水溶液稳定性有显著影响.80℃时,芦荟苷8h降解率高达98%;而在5℃时,4d降解率低于5%.当pH≥7时,芦荟苷在12h内降解率超过95%;而pH=2.0时,4d降解率只有21.1%.Mn2+,Cu2+,Fe3+等对芦荟苷降解具有促进作用,而Mg2+则对芦荟苷降解有抑制作用.     

芦荟提取物对水包油型乳液的抗氧化性能影响

在水包油乳液中添加芦荟提取物,考查了芦荟提取物的添加量、温度和紫外光对乳液的过氧化值以及羟基自由基清除能力的影响.结果表明：室温下添加8 mL芦荟提取物放置5 h时,乳液的过氧化值比未添加小20.64%;室温下用紫外光照射5 h时,添加芦荟提取物的乳液的过氧化值比未添加小16.73%;40 ℃温度下加热5 h时,添加4 mL芦荟提取物的乳液的过氧化值比未添加小21.76%.羟基自由基清除能力实验说明乳液添加芦荟提取物后,羟基自由基清除率是未加的5.5倍.     

芦荟的毒性研究

用体外细胞培养的方法分别研究了芦荟叶皮、芦荟凝胶和芦荟全叶的提取物对HepG2细胞和BALB/c3T3细胞的毒性作用,结果表明芦荟提取物对受试细胞没有产生毒性作用,由此可知芦荟产品是安全的.     

热水浸提法提取库拉索芦荟花多糖的研究

采用热水浸提法提取库拉索芦荟花多糖,对温度、时间、加水量、芦荟花粒度4个工艺条件进行了研究.本实验条件下,芦荟花多糖提取的最佳条件为:温度:100℃;粒度:40-60目;时间:4 h;加水量:100 mL.分两次提取比单次提取多糖收率可提高10%.     

芦荟果冻生产工艺研究

研究了以芦荟为主要原料的果冻生产工艺,分析了卡拉胶用量、柠檬酸用量、糖用量对芦荟果冻产品的影响。确定了卡拉胶、柠檬酸、糖的比例,以卡拉胶1％,白糖19.96％,葡萄糖17.83％,柠檬酸0.6％为最佳用量。利用感官评定和仪器分析方法确定了芦荟果冻的合理配方及加工工艺参数,研制出芦荟果肉果冻产品。     

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