米曲霉固体发酵生产中性蛋白酶产酶条件研究

为探讨米曲霉固体发酵生产中性蛋白酶的产酶条件,以米曲霉Y10为试验菌株,研究了产中性蛋白酶活力较高的固体培养基配方.结果表明:米曲霉产中性蛋白酶的适宜培养条件为:m(麸皮)∶m(酵母粉)∶m(乳糖)∶m(水)=9∶1∶1∶9,pH值为7.0,接种量为每克培养基接种1.8×108个孢子,最佳培养温度为30℃,最佳培养时间为72h.在此培养条件下,最高酶活力达4286.1U/g.     

鸡肉蛋白水解液的研究

用酶水解鸡肉 ,通过单因素实验确定胰蛋白酶 1、中性蛋白酶、木瓜蛋白酶、酸性蛋白酶、碱性蛋白酶、胰酶 2、胃蛋白酶水解鸡肉的最适条件 ,并确定在它们的最适条件下 ,胰蛋白酶和木瓜蛋白酶是单酶水解较好的酶。在双酶水解中 ,发现胰蛋白酶 1与酸性蛋白酶在各自最适条件下组合水解鸡肉水解率最高 ,进一步确定双酶水解的条件为胰蛋白酶先在 5 0℃ ,p H8.5 ,加酶量 40 0 0 U/ g蛋白质 ,固液比 1∶ 4,水解 3h,后酸性蛋白酶在 45℃ ,p H2 .5 ,加酶量 40 0 0 U/ g蛋白质水解 2 h。在这种组合下酶解 ,水解产物的水解度为 40 .5 % ,蛋白回收率为 81.0 %     

血管紧张素转换酶(ACE)抑制肽的酶法制备

以扇贝裙边的酶解产物——蛋白多肽对ACE活性的抑制率作为控制水解程度的指标,确定制备ACE活性抑制肽的最佳酶种及酶解工艺技术条件.通过胰蛋白酶、胃蛋白酶、木瓜蛋白酶、复合风味酶、枯草杆菌蛋白酶5种酶酶解扇贝裙边得到的蛋白多肽对ACE抑制能力的比较发现,5种酶在不同酶解时间所得到的酶解蛋白多肽都具有一定的ACE抑制能力,其中胃蛋白酶酶解蛋白多肽的ACE抑制率最高,为91.33%;再经L9(3)4正交实验对胃蛋白酶酶解工艺条件进行优化,确定酶解反应最佳条件是酶量400 U.g-底1物,pH 2.5,温度32℃,底物浓度(原料∶水)1∶2,酶解时间3 h;试验结果还表明,单酶(胃蛋白酶)的酶解蛋白多肽比复合酶(复合风味酶)和双酶(胃蛋白酶 木瓜蛋白酶)的酶解蛋白多肽对ACE活性的抑制能力都强.     

蛋白酶水解骨素的对比及其优化研究

选取木瓜蛋白酶、中性蛋白酶、风味蛋白酶分别对骨素进行酶解,对比了几种酶解液的苦味和水解度.结果表明:风味蛋白酶最适合酶解骨蛋白,其水解产物鲜味明显,无明显苦味;木瓜蛋白酶水解骨蛋白效果最差,其水解产物苦味最为明显;中性蛋白酶水解效果介于风味蛋白酶和木瓜蛋白酶之间.风味蛋白酶水解骨蛋白的最佳酶解条件为:温度50℃,加酶量6 000 U/g底物蛋白,p H值为7.0,酶解时间2 h,料液比1∶5(g/m L),在此条件下其水解度可达34.80%.     

用响应面法优化酶水解法制备葵花盘小分子肽

为提取并利用葵花盘中具有降尿酸和溶解痛风石作用的小分子肽, 以小分子肽得率为指标, 通过酶水解法优化提取条件, 确定碱性蛋白酶为最理想的酶. 通过单因素实验考察料液比、 时间、 温度、 pH值和加酶量对小分子肽得率的影响, 利用响应面Box-Behnken实验, 优化酶水解法提取葵花盘小分子肽的工艺, 得到其最佳工艺条件为： 加入碱性蛋白酶, m(料)∶V(液)=1∶15, 酶的用量为2%, pH=9.0, 温度为55 ℃, 时间为2 h, 葵花盘小分子肽的得率最高为(42.41±0.01)%.     

用响应面法优化酶水解法制备葵花盘小分子肽

为提取并利用葵花盘中具有降尿酸和溶解痛风石作用的小分子肽, 以小分子肽得率为指标, 通过酶水解法优化提取条件, 确定碱性蛋白酶为最理想的酶. 通过单因素实验考察料液比、 时间、 温度、 pH值和加酶量对小分子肽得率的影响, 利用响应面Box-Behnken实验, 优化酶水解法提取葵花盘小分子肽的工艺, 得到其最佳工艺条件为： 加入碱性蛋白酶, m(料)∶V(液)=1∶15, 酶的用量为2%, pH=9.0, 温度为55 ℃, 时间为2 h, 葵花盘小分子肽的得率最高为(42.41±0.01)%.     

响应面法优化银鱼多肽的酶解工艺研究

为了提高银鱼的附加值,采用蛋白酶水解其蛋白制备银鱼多肽.以水解度为优化指标,确定酸性蛋白酶为最佳用酶,研究了温度、pH、料液比和加酶量对水解度的影响.用Design-Expert 8.0软件进行响应面最佳条件优化,确定最适水解条件为:41℃,pH 4.0,料液比1∶52,酶解时间6h和加酶量2.3%.优化后水解度达到15.13%,为银鱼的综合利用提供了一种新方法.     

超声波辅助酶解法制备香菇酱

在蛋白酶水解法制备香菇酱的工艺中,首先研究了超声波对原料进行细胞破碎处理的操作条件,采用正交实验设计对影响蛋白酶水解效果的条件进行了选择优化。结果表明,超声波处理的最佳功率为200W、最佳处理时间为30min,蛋白酶水解的最佳工艺条件为酶解温度40℃、pH值4．5、酶用量1％、酶解时间60min,在此工艺条件下香菇酱的氨基酸含量为0．88％。     

湿法制备氧化亚铜微晶过程及其综合形貌控制

在碱性环境下,以CuSO4.5H2O为原料、葡萄糖为还原剂,采用湿法还原法制备Cu2O微晶.研究反应物摩尔比、反应温度、反应时间、添加剂用量及pH值对产物的收率、粒径和色泽的影响.通过对产品综合性能的分析表明,较佳反应条件为:n(CuSO4.5H2O)∶n(CH2OH(CHOH)4CHO)=1.2∶1,70℃下反应80min,硫酸铜用量为30.0g,添加剂聚乙烯吡咯烷酮(PVP)用量为2.0g,反应体系pH=10.     

氯化锡催化合成苯甲酸乙酯的研究

以苯甲酸和无水乙醇为原料,采用氯化锡(SnCl4·5H2O)作催化剂合成苯甲酸乙酯,考察了催化剂用量、原料配比和反应时间等因素对反应产率的影响.确定了氯化锡作为催化剂的最佳反应条件:n苯甲酸∶n无水乙醇∶n氯化锡=1∶4∶0.01;反应温度为88℃;反应时间为60min;转化率(以苯甲酸计)可达93.5%.     

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