响应面法优化啤酒酵母海藻糖提取工艺

采用响应面法(RSM)优化提取啤酒酵母泥中海藻糖的醇提法工艺条件,对乙醇质量分数、醇提温度和醇提时间3个因素进行单因素实验;根据单因素实验结果,设计中心组合实验,以海藻糖提取得率为指标,RSM分析法确定最优工艺参数。结果表明:在乙醇体积分数为52.20%、温度在81.23℃处理1.41 h条件下,海藻糖提取得率的实测值为10.49%,模型预期值为10.57%,响应面优化法提高了酵母海藻糖的得率。     

灰树花菌丝体中海藻糖提取条件的研究

研究采用正交试验法、微波辅助提取灰树花菌丝体中海藻糖的条件,并用蒽酮-硫酸法对灰树花菌丝体中海藻糖含量进行了测定。确定了海藻糖提取条件的最佳组合:提取液为三氯乙酸,提取温度为30℃,提取时间为45min,液料比为1∶25。     

超声波法结合响应曲面法优化葡萄籽中原花青素的提取工艺研究

研究以单因素实验结果为依据,采用三元二次旋转组合设计及响应曲面分析法,研究了以时间、温度及料液比三个条件对葡萄籽中原花青素提取率的影响。试验结果显示:最佳提取条件是提取温度44.99℃,料液比1∶12(g/ml),提取时间15.37 min,预测提取率可达19.93%,在此条件下通过实验验证,原花青素的提取率为19.97%。将提取的原花青素纯化,并与标准品通过红外和高效液相检测,峰形和出峰时间基本一致。     

酵母胞内海藻糖微波破细胞提取与传统提取比较

酵母胞内海藻糖大都采用 50 %乙醇 -水溶液回流提取得到 .但酵母经微波破细胞处理后 ,以水为溶剂在室温下提取 1 0 min,就能把海藻糖充分溶出 .与传统浸取相比较 ,微波破细胞提取具有提取时间短、不需有机溶剂、不需加热、海藻糖收率高、杂质溶出少等优点     

Box-Behnken设计优化山楂叶总黄酮提取纯化工艺及其抑菌活性研究

利用Box-Behnken设计优化山楂叶总黄酮的提取及纯化工艺,优化实验表明,提取工艺参数:提取剂乙醇体积分数65%、提取温度(67±1)℃、提取时间80 min,山楂叶总黄酮提取率可达92.2%;纯化工艺参数:洗脱剂乙醇体积分数60%、洗脱剂用量4.4倍柱床体积(BV)、洗脱流速3.7 BV/h,提取物中山楂叶总黄酮平均质量分数可达86.8%.此为最佳提取工艺和最佳纯化工艺参数.体外抑菌试验表明,山楂叶提取物对金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌均具有良好的抑菌功效.     

假酸浆多糖提取纯化工艺的研究

以假酸浆籽为原料,采用水提法、超声波提取法、微波提取法提取假酸浆多糖,经对各提取过程比较分析可知水提法为最优提取方法,提取条件为料液比1∶55、温度80℃、时间3 h,提取率为6.18%.将水提法得到的假酸浆多糖浓缩液通过醇沉、脱蛋白、脱色等工艺进行纯化,确定了最佳的提取纯化工艺.在最佳的条件下,醇沉后多糖的量可达80.5%,蛋白质脱除率可达70.8%,脱色率可达91.0%.     

番茄红素的提取及纯化条件的研究

对番茄中番茄红素的提取和粗制品的纯化条件进行了研究,实验证实,选用丙酮作为提取剂,液料比8∶1,提取温度50℃,提取时间30min时,提取效果最佳.进一步利用单因素分析法和正交实验法确定了洗涤纯化的条件,从而得出碱洗与盐洗的最佳条件.碱洗的最佳条件:用1mol/L NaOH溶液,洗涤时间1h,温度40℃;盐洗最佳条件:用20%NaCl溶液,洗涤时间为1h,洗涤温度50℃.搅拌的纯化效果比不搅拌的好.     

酵母胞内海灌糖微波破细胞提取与传统提取比较

酵母胞内海藻糖大都采用50％乙醇－水溶液回流提取得到。但酵母经微波破细胞处理后,以水为溶剂在室温下提取10min,就能把海藻糖充分深出,与传统浸取相比较,微波破细胞提取具有提取时间短、不需有机溶剂、不需加热、海藻糖收率高、杂质溶出少等优点。     

海藻糖对银杏叶过氧化物酶活性的影响

对银杏叶过氧化物酶热稳定性、最适pH值及海藻糖对酶热稳定性的保护作用和pH值的影响进行了初步研究.结果表明,用40℃和50℃分别处理30 min,过氧化物酶活性分别剩余78%和39%,在60,70,80℃下活性可分别维持27,18和3 min.银杏叶过氧化物酶最适pH值为6.4和9.2.加入海藻糖后酶活性略有降低(活性丧失约8%),但加热后海藻糖的保护优势得以显现,海藻糖浓度为0.14 mol/L时保护效果最好,而且不同温度处理下酶活的下降趋势均较对照组缓慢,尤其在50,60,70℃条件下,相比对照组高出12%~27%的活性,加热时间长短对海藻糖的保护效果无太大影响.经0.14 mol/L浓度的海藻糖处理后,酶活的最适pH值为6.6和9.4.     

从鱼腥草中提取鱼腥草素分离工艺研究

利用溶剂提取法从鱼腥草中提取鱼腥草素．研究了乙醇浓度、固液比、提取时间、提取温度等工艺条件对鱼腥草素提取率的影响,最佳提取工艺条件为:以50%乙醇溶液为溶剂,固液比1:30,温度50℃,时间65min,提取率可达11．0%．     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the