响应曲面法优化酸/盐催化玉米芯产糖的工艺

将生物质水解转化成可发酵糖是生物转化利用的重要途径。本研究以玉米芯为原料,在传统单酸催化剂水解的基础上,研究了H2SO4/Fe2(SO4)3催化剂对玉米芯水解产糖的影响,结果表明:当单独采用H2SO4或Fe2(SO4)3催化玉米芯水解时,总糖产率均低于40%;而将H2SO4、Fe2(SO4)3混合后催化水解时,总糖产率高于使用2种单催化剂所得总糖产率之和。采用响应曲面法优化了H2SO4/Fe2(SO4)3催化玉米芯水解的工艺条件,通过验证实验得到:当H2SO4浓度为0.7 mol/L,Fe2(SO4)3浓度为2.0 mol/L,反应温度为150℃,时间为47 min时,玉米芯水解所得的总糖产率最高,为79.98%。本研究通过对玉米芯水解条件的优化,提高了玉米芯水解制糖的产率,为玉米芯的高值化利用奠定应用基础。     

蜗牛水解液的制备及其乳酸发酵饮料的研究

用碱性蛋白酶对白玉蜗牛肉进行水解,探讨了水解温度、pH值、加酶量及固液比对蜗牛肉水解液水解得率的影响,通过正交试验确定了蜗牛肉水解的较佳条件,并以水解液为原料进行乳酸菌发酵,获得较佳的饮料制备工艺.结果表明:以碱性蛋白酶为水解酶,水解工艺条件为,温度50℃,pH 10.5,料液比1:5,加酶量6 000 U/g,水解3 h后加1%风味蛋白酶水解1 h时水解度为7.13%.水解液乳酸菌发酵的较佳工艺条件为:115℃高温灭菌15 min,蔗糖添加量5%,乳糖添加量2%,乳酸菌接种量3%～4%,时间6 h.     

玉米芯中木聚糖水解制备D-木糖的试验研究

研究了利用玉米芯为原料制备D-木糖的试验条件.经过详细的实验条件考察,得知玉米芯中木聚糖水解为D-木糖的最佳水解条件:硫酸质量分数为2.5%,反应温度为110℃,玉米芯质量(g)和硫酸体积(mL)的比值即固液比为1∶8,反应时间为3 h.木聚糖的水解率达到97.89%.水解液经过石灰水中和、活性炭脱色、乙醇洗涤等过程的脱毒处理,纯度可以达到97.8%,木糖的提纯率为57.6%.     

甜玉米芯多糖脱色工艺研究

采用双氧水法对甜玉米芯多糖进行脱色研究,分别选H2O2用量、温度和时间进行单因素试验.在此基础上,研究三种因素对甜玉米芯脱色率及多糖损失率的影响.结果表明双氧水脱色的最佳条件:温度为40℃,添加量为40%,时间2 h.此条件下多糖溶液脱色率为60.21%,多糖保留率为77.69%.     

酶法提取甜玉米芯多糖的对比研究

采用酶法提取甜玉米芯多糖,分别选取纤维素酶、果胶酶和木瓜蛋白酶进行单因素试验.在此基础上,研究三种酶同时添加和分步添加对甜玉米芯多糖得率的影响.结果表明,分步添加法比同步添加法对甜玉米芯多糖提取的效果显著,即先加木瓜蛋白酶(添加量2.0%,p H=7,提取温度50℃,时间1.5 h);然后加果胶酶(添加量1.0%,p H=6,提取温度50℃,时间1.5 h);最后加纤维素酶(添加量1.5%,p H=7,提取温度50℃,时间1.5 h),该条件下多糖得率为42.37%.     

大豆秸秆纤维素菌水解条件的研究

以氨水预处理大豆秸秆为原料,研究了康氏木霉固态发酵产纤维素酶及纤维素酶水解的条件,结果表明:较适宜的产酶条件是温度30℃,pH5.0,培养基固液比1∶2.5,时间为96h,产纤维素酶活力为798.84FPU L,以所产纤维素酶进行酶水解,较适宜条件为:温度55℃、pH为5.6、时间36h、酶水解率为6.98%.由液相谱图经定性分析知酶解液的主要成分为葡萄糖、纤维二糖和木糖,为下一步乳酸发酵实验提供了参考数据.     

木聚糖酶固体发酵条件的试验

对采用黑曲霉C3486固态发酵生产木聚糖酶的条件进行了研究.确定了所试因素的最佳组合：麸皮与玉米芯的比例为7∶3,氮源是1.0%硫酸铵,培养基起始pH值为自然pH值,250mL三角瓶中装培养基15g,培养时间为72h,温度为40℃,接种量为5%.在上述条件下木聚糖酶的平均产量可达14kU/g.     

玉米威士忌生产工艺研究

为降低生产成本、改善产品口味,将玉米粉作为威士忌生产原料,部分代替大麦芽用于制作谷物威士忌,以出酒率和感官得分作为产品的考核指标,对麦汁比例、酵母接种量、发酵温度、发酵时间等因素进行了研究。结果表明:出酒率的影响因素顺序为发酵温度影响最大,其次是发酵时间和接种量,麦汁比例的影响最小;感官得分的影响因素顺序为发酵温度影响最大,其次是接种量和发酵时间,麦汁比例的影响最小。出酒率的较优生产条件为麦汁添加比例为20%,添加1.0%的酵母在20℃条件下发酵11 d;感官得分的最适条件为麦汁添加比例为25%,添加0.8%的酵母在16℃条件下发酵15 d。     

一株产木聚糖酶菌固体发酵条件的优化

采用单因素试验设计对黑曲霉发酵产木聚糖酶的条件进行了研究,并探讨了黑曲霉发酵的产酶模式.以麸皮和玉米芯质量比7:3混合后作为碳源,含0.15%的硫酸铵为无机氮源,物料与水分的比为1:1.5,培养温度28～30℃,培养基起始pH值为4.8,接种量为4%(107个/mL),外加吐温-20±0.05%,发酵时间为72h,用10倍培养基的自来水,40℃摇床浸提1h,木聚糖酶活可达650.45U,为木聚糖酶固体发酵的工业化生产和应用提供参考.     

木聚糖酶液体发酵条件的试验

研究了利用黑曲霉C3486液体发酵生产木聚糖酶的最佳条件:3%玉米芯木聚糖为碳源,3%的蛋白胨为氮源,培养基起始pH值为7.0,250mL三角瓶中装培养基50mL,培养时间为72h,温度为35℃。在上述最适条件下木聚糖酶的最高产量为14240U/mL,平均为14230U/mL。     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

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.     

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