双极膜电渗析提取乳酸的影响因素

针对乳酸传统生产工艺废水排放多、产品质量较差的问题,提出两室型双极膜电渗析生产工艺,探索适合工业生产的操作条件。研究结果表明:电流密度对电渗析过程影响最大,提高初始浓度和增加极室盐溶液浓度均能使能耗降低。对1.24 mol/L的乳酸钠溶液,控制电流密度为500 A/m2,流量为80 L/h,极室盐质量浓度为50 g/L时,乳酸收率93%,浓度1.42 mol/L,电流效率72.5%,能耗1.05 kW.h/kg。     

BMED 解离硫酸盐高效清洁制酸碱工艺

 随着工业生产的快速发展,工业废水的排放量迅猛增加,其中大部分工业废水中都含有硫酸盐,硫酸盐的过量排放会对环境水体造成严重的污染与破坏。本研究以硫酸钠废液为原料,采用双极膜电渗析(BMED)新型工艺,实现含硫酸盐废水的回收再利用,高效、清洁地制取酸、碱。实验主要考查了电流密度、原料液浓度及初始酸碱浓度对膜堆性能的影响,并对两种离子交换膜的性能进行对比。结果表明,实验范围内,氢氧化钠的收率高达84.08%,平均电流效率为54%,能耗为5.29 kW·h/kg;氢氧化钠收率和过程能耗均随电流密度的增大而增加;电流密度恒定时,较高的原料液浓度可使膜堆电阻维持在较低的水平,进而降低能耗;适量加入初始酸碱能够降低能耗,但也会降低电流效率。     

异相膜电渗析法处理苯酚废水

提出通过向苯酚溶液中加入碱,然后用异相离子交换膜电渗析法去除酚氧离子的含酚废水处理工艺,考察了加碱量、苯酚初始浓度、操作电压、流量对苯酚去除率的影响,并测定极限电流密度,计算了能耗。实验结果表明,电渗析法处理含苯酚废水,能耗低,操作方便,具有较好的效果,对于质量浓度为1000mg/L的含苯酚废水,加入氢氧化钠的量使n苯酚∶n氢氧化钠=1∶5,操作电压为26 V,流量均为50 L/h,实验时间为120 min的条件下,淡室苯酚去除率达到了98.2%。     

乳酸钠对镁合金微弧氧化膜层性能的影响

在NaAlO2、KH2PO4复合体系中添加不同浓度的乳酸钠对镁合金进行微弧氧化处理,研究了陶瓷层生长速率随乳酸钠浓度的变化规律,并对陶瓷层采用扫描电镜进行表面形貌观察;利用X射线衍射仪对膜层相组成进行分析,用电化学工作站进行动电位极化曲线测试.结果表明:乳酸钠浓度为3 mL/L时所获得的膜层致密性较好并具有最佳的耐蚀性.     

电渗析浓缩高盐溶液:阴阳离子交换膜匹配性关系（英文）

研究了阳离子交换膜和阴离子交换膜的匹配性对电渗析浓缩性能的影响,主要考察了电渗析过程中的盐通量、水通量、水盐通量比和电渗析浓缩液的浓度.实验结果表明,当阳离子交换膜具有合适的离子交换容量时,阳离子交换膜的水含量对电渗析的浓度性能有着重要的影响;相比于离子交换容量和水含量,阴离子交换膜的离子渗透性对电渗析浓缩性能有着更加重要的影响.此外,当阳离子交换膜和阴离子交换膜均具有较高离子渗透性时,阳离子交换膜对电渗析浓缩的影响更为重要.     

双极膜电解提溴吸收完成液制备HBr和NaOH

采用双极膜电渗析(BMED)技术,对以提溴吸收完成液为原料电解制备NaOH和HBr的过程进行了研究。系统考察了电流强度、原料液初始质量浓度以及酸碱浓度等对实验的影响,以及在盐室的NaBr溶液中加酸的实验效果,用来模拟以甲酸钠溶液为吸收液的提溴吸收完成液。结果表明:适当提高膜堆的直流电强度有利于产酸产碱,但是电流效率更低,能耗更高,综合考虑,实验采用的电流强度为2.5～3.0 A。当原料液NaBr的初始质量浓度为40～50 g/L以及酸碱初始浓度为0.1～0.2 mol/L时,电流效率较高,能耗较低。随着酸碱初始浓度增加,电流效率和能耗的变化变小。在NaBr原料液中加酸会抑制碱的产生,相反产酸量则会大大提高。     

超滤去除L-乳酸发酵液中蛋白的工艺研究

采用超滤技术从L-乳酸发酵液中分离去除蛋白,研究了超滤过程中的操作压力、操作温度、超滤液的体积和料液初始浓度等主要因素,对膜通量和发酵液中蛋白质及乳酸钙2种主要组分截留率的影响;并确立了采用聚砜膜去除乳酸中蛋白工艺的最佳参数,在此条件下,蛋白质去除率达到91.5%,乳酸钙损失为2%。     

多排石墨芯基体NiHCF膜电极的制备与电控离子分离性能

以多排石墨芯(MRGC)为基体材料, 采用阴极沉积法制备了具有电化学控制离子分离(ECIS)性能的电活性NiHCF膜电极.采用SEM和XPS分析考察了NiHCF薄膜的形貌与组成;在1 mol/L的NaNO3溶液中通过循环伏安法可逆地置入与释放Na+, 考察NiHCF膜电极的离子交换容量、再生性能;在1 mol/L(NaNO3+CsNO3)混合溶液中比较不同混合浓度下膜电极的伏安特性曲线, 分析了膜电极对Cs+/Na+的选择性.同时采用离子色谱测定了氧化态NiHCF膜电极在初始[Cs+]为10 mg/L模拟液中进行ECIS过程的Cs+浓度变化.实验结果表明, MRGC基体NiHCF膜电极离子交换容量大、再生能力好, 对Cs+有较强的选择性, 可用于Cs+的电控离子分离过程.     

聚偏氟乙烯支撑液膜萃取乳酸

采用聚偏氟乙烯固体微孔膜,与溶解在煤油中的三烷基氧磷组成支撑液膜(SLM),分离稀水溶液中的乳酸。考察了pH值、料液浓度、载体浓度、温度、料液及解析液流量对传质速率的影响。同时进行了膜稳定性的定性研究。发现乳酸以分子形式通过SLM;载体浓度为40%时传质速率最大;SLM对乳酸的通量与稀水溶液中乳酸浓度成正比。料液和解析液预先用有机相饱和时,膜的稳定性可大大改善。     

两种方法测定乳酸钠林格注射液中乳酸钠的含量

乳酸钠林格注射液是常用的临床营养输液制品．用于体液、电解质及酸碱平衡调节。其主成分乳酸钠含量的测定《中华人民共和国》2005版采用氧化还原滴定法,该法操作比较繁琐,检测时间长。本文在验证了此法的基础上,采用高效离子交换色谱法对乳酸钠林格注射液中乳酸钠的含量进行测定．并比较了两种方法各自的特点,论证了高效离子交换色谱法的可行性。     

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.     

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