Some aspects of the present status of the thermodynamics of electrolytic solutions

We have surveyed in a brief manner some phases of the experimental thermodynamics of electrolytic solutions. A more complete review would be very voluminous, and would include a number of other topics. As examples, the investigations of electrolytes of higher valences types such as cadmium chloride (34), and iodide (8), barium chloride (85), and zinc sulphate (11) (55). It would also include a discussion of the important work of Gibson (14) who has measured the compressions of a number of aqueous salt solutions up to 1000 bars. Nor have we discussed the recent interpretations of the behaviors of strong electrolytes in solutions at higher concentrations where the theory of Debye and Hückel is no longer adequate without considerable extension. This complicated subject has been investigated most comprehensively by Scatchard (78) (80) and its discussion would lead beyond the intended limits of this survey. We trust that this sketch of our results will help somewhat to give a correct impression of the extent and direction of this part of solution chemistry. The development of method in these studies of equilibria has reached the stage where a really reliable and accurate body of evidence is becoming available. This is very important because accurate data will be required not only as criteria and as a guide to the approximate statistical and quantum mechanical interpretations of equilibrium constants, entropies, activation energies, and reaction velocity constants where ions are involved, but also in the further clarification of the state of ions in solution.     

Mobilities of gaseous ions in CH3NO2H2 and CH3CNH2 mixtures

Extending previous investigations by Loeb of mobilities in gaseous mixtures using his procedure except that the auxiliary field in these measurements was made equal to the advancing field thus giving absolute values of the mobilities, measurements of mobilities were made in mixtures of CH₃NO₂H2 and CH₃CNH₂. The mobilities in H₂ were 7.12 for the positive ions and 10.46 for the negative ions in cm./sec. per volt/cm. Those in CH₃NO₂ were 0.221 cm./sec. per volt/cm. for both ions and in CH₃CN they were 0.234 cm./sec. per volt/cm. for both ions. Both ion mobilities deviated from Blanc's law in CH₃NO₂ indicating the formation of complexes with the CH₃NO₂ ions somewhat greater in size than the normal ions in H₂. The molecules attached to negative ions somewhat less readily than to the positive ions but both final ions were of the same size. In CH₃CN mixtures both positive and negative ions deviated from Blanc's law, the positive ion showing more ready attachment of CH₃CN. The negative ion had consistently a higher mobility than the positive ion, a circumstance indicating a smaller ion and suggesting that the attaching molecule might not be CH₃CN but some impurity. Both ion addition products in CH₃CN are larger than the normal ion in H₂ but smaller than those in CH₃NO₂ as was to be expected.     

Microscale pH regulation by splitting water

We present a simple, flexible approach for pH regulation in micro-chambers by injecting controllable amounts of protons and hydroxide ions via field-enhanced dissociation of water molecules. Under a DC voltage bias, the polymeric bipolar membranes integrated in microfluidics devices generate and separate H(+) and OH(-) ions without gas production or contaminant generation resulting from electron-transfer reactions. Robust local on-chip pH and pH gradients are sustained with no need of additional acidic∕basic solutions that dilute analyte concentrations. The method could provide a better strategy for pH control in microfluidics.     

The effect of electron attachment on the ion mobility curves in the Zeleny air blast method of ion mobility measurement

In a recent paper Professor John Zeleny published curves obtained for ion mobilities at different ion ages in relatively pure N₂ using his classical air blast method. Two features are of especial interest; one the apparent gradual displacement of the negative ion peak to lower mobilities as the ion age increases and the other a marked asymmetry of the electron peak on the low mobility side. This Zeleny interprets as an unresolved negative ion mobility of value about 100 cm./sec. per volt/cm. Such a mobility can only be explained by a carrier that is ion part of its life and electron part of its life, the electronic and ionic phases alternating frequently. The writers indicate that the latter interpretation cannot be correct on the basis of the energies and probabilities involved in electron attachment. Analysis shows that the whole series of the observed phenomena in N₂ by this method are successfully accounted for on the proper application of the simplified theory of electron attachment to the air blast method. Since the attachment phenomena have to date not been applied to this type of mobility study it was felt of importance to present this analysis in order to guide future investigations by this method.     

The role of surface instability in electrical discharges from drops of alcohol and water in air at atmospheric pressure

A study of previous work on discharges from charged attached drops and from uncharged drops falling in electric fields shows that the surface electric intensities at these drops, when the discharges begin, satisfy the theoretical relations for surface instability. Glow discharges, if initially present, are conditioned by the surface deformation arising from instability. Experiments are described that indicate that the highly charged droplets ejected by an alcohol surface may have mobilities not much below those of normal air ions while such droplets coming from a water surface may have mobilities even greater than those of air ions. Calculations, by Stokes' Law, show such large mobilities for both kinds of drops to be possible. Further experiments show that under certain conditions the whole discharge current from an alcohol drop is carried solely by droplets of the liquid, resulting from surface instability, and under more restricted conditions the same may be true for a water drop.     

Behavior of positive ions in hydrogen

It has been shown that electrons with 11.5 volts energy can dissociate a hydrogen molecule into its two constituent atoms, but up until recently no experiments have been performed to see whether fast positive ions are able to dissociate hydrogen.In the present experiments Li or Cs positive ions of various velocities are produced in a tube containing hydrogen molecules. The tube is immersed in liquid air, and the rate of decrease of pressure of hydrogen is measured as a function of the velocity of the positive ions. It is found that with no positive ions entering the tube there is a certain decrease in the pressure of the hydrogen due to its thermal dissociation on the hot filament and its subsequent condensation on the cold walls of the tube. With ions of energies from 15 to 320 volts flowing in the tube the rate of decrease of pressure is greater, showing a formation of some condensible product due to the action of the ions.The rate of pressure decrease with the voltage applied has been found to be proportional to the ion current flowing. The rate per unit current is proportional to the pressure; and the rate per unit current per unit pressure is practically independent of the voltage for Li and Cs ions of energies from 15 to 320 volts.The effect has been shown not to be due to secondary electrons.The process may be due to the formation of alkali hydrides in the gas phase. The number of hydrogen molecules disappearing per positive ion entering the tube varies from 0.01 to 0.5. No critical potentials have been found in this experiment, in disagreement with recent experiments of Leipunsky and Schechter.     

海峡西岸经济区旅游景区(点)空间结构分析

本文以4A级景区（点）为例,基于GIS技术,通过地理集中指数、分布椭圆、最近邻指数等方法分析海峡西岸经济区旅游景区的空间结构特征。结果表明：厦门是旅游景区资源最丰富的城市;旅游景区总体上在市际尺度呈集中分布趋势,在空间上呈聚集分布;自然景点、红色景点和客家景点是主要景点类型和特色景点类型,其分布范围与区域自然地貌特征、历史文化渊源相符;自然景点、红色景点、客家景点在市际尺度上都呈集中分布趋势,在空间上自然景点、红色景点呈均匀分布,客家景点呈聚集分布。本文认为自然地貌特征与历史文化渊源、城市经济发展水平、政府参与是影响海峡西岸旅游景区空间结构的主要因素,并基于此提出一些优化旅游景区空间结构的措施。     

Transport and separation of micron sized particles at isotachophoretic transition zones

Conventionally, isotachophoresis (ITP) is used for separation of ionic samples according to their electrophoretic mobilities. We demonstrate that the scope of ITP applications may be extended toward particle concentration and separation. Owing to the distributions of electrolyte concentration and electric field inside a transition zone between two electrolytes, a number of different forces act on a small particle. As far as possible, we provide estimates for the order of magnitude of these forces and analyze their scaling with the particle size and the electric-field strength. Furthermore, we experimentally demonstrate that polymer beads of 5 μm diameter dispersed in a high mobility “leading” electrolyte are picked up and carried along by an ITP transition zone which is formed with a low mobility “trailing” electrolyte. By studying the particle positions and trajectories, we show that impurities in the electrolytes play a significant role in the experiments. Additionally, it is experimentally shown that different types of beads can be separated at an ITP transition zone. In particular, beads of 1 μm diameter are not carried along with the transition zone, in contrast to the 5 μm beads. The presented technique thus adds to the portfolio of electrokinetic transport, concentration, and separation methods in microfluidics.     

Experimental verification of Faradaic charging in ac electrokinetics

This paper investigates the phenomenon of Faradaic charging in ac electrokinetics. Faradaic reactions were suggested as a key effect responsible for the reversal of pumping direction in ac micropumps. However, this hypothesis has yet to be proven convincingly and directly. Here we present an ion detection strategy to determine the production of ions through Faradaic hydrolytic reactions originating from direct application of voltage to electrolytic solutions during ac electrokinetics. Experiments were performed with symmetrical planar electrodes aligned along a microfluidic channel. Fluorescein, a pH-dependent dye, was employed as the pH indicator for the detection of ion production. Images were captured for analysis at various voltage levels. From analyzing the fluorescence intensity and its distribution, it can be concluded that the production of ions from hydrolytic reactions takes place and increases with the ac voltage. The coefficient of deviation indicates a significant enhancement at ac voltage above 11 V_pp. Lastly, we demonstrate a strategy using dc-biased ac electrokinetics to achieve controllability in direction and magnitude of the net fluid flow in pumping application.     

The effect of the surface functionalization and the electrolyte concentration on the electrical conductance of silica nanochannels

It is known that the conductance of nanochannels as a function of electrolyte concentration deviates from a linearly proportional relationship and approaches a value independent of the concentration as the electrolyte concentration is lowered. Most of the proposed models account for this behavior by considering a constant surface charge density and an ideal electrolyte solution. However, at low electrolyte concentrations, the ideal electrolyte approximation is no longer valid because the ions that result from the atmospheric carbon dioxide dissolution in water dominate the ionic concentration. In this paper, arrays of silica nanochannels were electrically characterized via conductance measurements. The conductance at low salt concentrations is modeled by a variable surface charge model that accounts for all ionic species in solution. This model was used to determine the variable surface charge of the bare silica nanochannels as well as of chemically modified nanochannels. The model correctly predicted the variation of the nanochannel conductance observed after silane (aminopropyldimethylethoxysilane) functionalization and single-strand DNA immobilization. Finally, pH modification of bulk KCl solutions was employed as an alternative method of changing the surface charge of silica nanochannels. Surface charge calculated from conductance measurements performed at different bulk pH values confirmed that the surface charge of the silica nanochannel walls is sensitive to the H⁺ concentration.     

The theory of recombination of gaseous ions

The bearing of the recent results of Marshall on the theory of recombination of gaseous ions is discussed. It is shown, by solution of the Brownian movement equation for two ions of opposite sign, in a gas, that the average relative displacement in a time π is little influenced by the attractive forces, except for distances of the order of magnitude of 10^?5 cm. or less, at ordinary temperatures. This conclusion, that in general the motion of the ions relative to each other is largely one of random diffusion, is in good agreement with the interpretation forced by Marshall's study of the variation of the coefficient of recombination α with time and concentration of ions. This also indicates that the theoretical approach of Langevin to the solution of the recombination problem is untenable, while that of Thomson is justified. The theory, of Thomson is discussed and, is compared with observation. It appears to fit qualitatively as accurately as the facts are known.It is then shown how the success of any theoretical treatment is limited due to our ignorance of the nature of the mass of the ion, a condition which, however, enables us to understand the very small range of variation of α among the different gases.     

Perspective on fluorescence cell imaging with ionophore-based ion-selective nano-optodes

Inorganic ions are ubiquitous in all kinds of cells with highly dynamic spatial and temporal distribution. Taking advantage of different types of fluorescent probes, fluorescence microscopic imaging and quantitative analysis of ion concentrations in cells have rapidly advanced. A family of fluorescent nanoprobes based on ionophores has emerged in recent years with the potential to establish a unique platform for the analysis of common biological ions including Na⁺, K⁺, Ca²⁺, Cl⁻, and so on. This article aims at providing a retrospect and outlook of ionophore-based ion-selective nanoprobes and the applications in cell imaging.     

北京市音乐旅游资源分布规律研究

音乐旅游是文化旅游的重要组成部分,不仅能够拓宽旅游业发展的渠道,同时极大地丰富了居民的文化生活。本文选取北京市作为研究区域,对音乐旅游资源的分布规律进行了研究。在前期研究基础上,结合网络、文献、调研收集数据,将音乐旅游资源按功能分为3类：音乐表演场所旅游资源、音乐观光旅游资源、音乐休闲旅游资源,并将不同功能、定位和性质的音乐旅游资源结合起来,建立了北京市音乐旅游资源采样数据库,采用GIS空间分析技术得出结论。研究发现,北京市音乐旅游资源整体上是以国家大剧院为核心,呈同心圆向外扩散分布。且均以交通为主导,沿市内环路和主要地铁线分布。音乐表演场所旅游资源依托于音乐院校、歌舞团和文化馆分布;政策性的扶持优化了音乐表演场所旅游资源的布局。音乐观光旅游资源发展依托于大型城市公园;其中,音乐文化创意产业呈集聚布局态势。音乐休闲旅游资源依托于大型商业中心和商业中心布局;且与饭店业布局规律基本一致。但整体而言,北京市音乐旅游资源分布不均匀,需要进一步优化和调整。     

Dissociative attachment

The reaction of an electron with a molecule AB which leads to dissociation of the molecule into a neutral component and a negative ion, is known as dissociative attachment. Such reactions are important sources of negative ions and may be used for the design of very sensitive detectors for certain compounds. They are of basic importance in determining the high dielectric strength of certain gases and vapours as well as in the design of gaseous lasers. The detailed study of the reactions leads to insight into reaction mechanisms and provides new information about molecular parameters. This article reviews the application of modern experimental and theoretical techniques to the subject.     

若干氢键团簇的纳秒和飞秒激光光电离及从头计算研究

利用纳秒和飞秒激光及飞行时间质谱仪对氮化苯 溶剂分子团簇的多光子电离和离解进行了研究。通过解决实验中的技术难题,实现了在气相条件下实验研究嘧啶与水团簇的多光子电离。首次观测到该团簇的多光子电离质谱,发现电离后形成了质子化团簇系列,通过团簇浓度随激光强度的变化以及理论计算,阐明了团簇内质子转移过程,以及电荷分布和质子转移过程随着团簇尺寸的变化;首次观测到吡啶团簇在飞秒光电离过程中的质子化和非质子化团簇离子共存的现象。非质子化吡啶二聚体离子的存在及高水平下理论计算表明,吡啶分子之间可以形成C -H N氢键,对文献中报道的结果给予了纠正,提供了弱氢键团簇中质子转移的一个极佳范例;首次研究并获得了嘧啶 甲醇以及哒嗪 甲醇氢键团簇的多光子实验研究结果.实验发现团簇经激光电离后只产生质子化产物,并从理论计算得到各种团簇的稳定构型,阐明了团簇发生电离后质子转移反应的过程和机理     

基于IEME的低碳化景区综合集成评价

低碳经济时代的演进,全球环境问题的凸显对全球旅游业的发展提出了新要求,旅游产业及景区的可持续发展寻求从传统的粗放型向新兴的集约型发展方式转变,如何促进景区低碳化建设,兼顾社会效益、经济效益与生态效益协调发展,实现景区可持续发展已成为社会各界关注的热点。针对国内外现有的旅游景区传统线性评价成果的不足,未能从复杂系统的角度体现景区系统低碳环保举措的成效及其效益的发展趋势。本文在复杂性科学管理熵与管理耗散结构理论的指导下,从经济运行、社会发展、生态环保、低碳控制、建设保障等维度构建低碳化景区多维综合集成评价体系,将管理熵增与管理耗散结构模型及改进后的熵值法应用于低碳化景区建设的评价过程中,从宏微观角度系统地揭示景区低碳化建设的系统序度、发展趋势。     

跨国技术转移的策略交互行为研究

已有的跨国技术转移研究虽然大多强调了技术转移的动态阶段特征,但却对技术授受双方呈现的阶段性行为选择机制缺乏有深度的认识,这对跨国技术转移问题研究而言无疑是一个瓶颈。跨国公司对东道国企业实施技术转移可以被视作双方间的合作博弈,出于对各自利益的维护,在技术转移中彼此都会运用占优策略以期获得目标收益。有鉴于此,本文运用复制动态模型对技术转移过程中双方的策略交互性进行了分析和研究。研究发现:随着技术保密成本、技术优势损失、东道国企业技术学习能力与意愿等变量的变化,跨国公司的技术转移力度表现出显著的策略选择性。     

Enabling Mg metal anodes rechargeable in conventional electrolytes by fast ionic transport interphase

Rechargeable magnesium batteries have received extensive attention as the Mg anodes possess twice the volumetric capacity of their lithium counterparts and are dendrite-free. However, Mg anodes suffer from surface passivation film in most glyme-based conventional electrolytes, leading to irreversible plating/stripping behavior of Mg. Here we report a facile and safe method to obtain a modified Mg metal anode with a Sn-based artificial layer via ion-exchange and alloying reactions. In the artificial coating layer, Mg₂Sn alloy composites offer a channel for fast ion transport and insulating MgCl₂/SnCl₂ bestows the necessary potential gradient to prevent deposition on the surface. Significant improved ion conductivity of the solid electrolyte interfaces and decreased overpotential of Mg symmetric cells in Mg(TFSI)₂/DME electrolyte are obtained. The coated Mg anodes can sustain a stable plating/stripping process over 4000 cycles at a high current density of 6 mA cm⁻². This finding provides an avenue to facilitate fast ion diffusion kinetics of Mg metal anodes in conventional electrolytes.     

丝绸之路申遗河南段洛阳旅游区形象营销策略研究

本文首先简述了丝绸之路及河南段洛阳旅游区申请世界文化遗产的概况,在此基础上对洛阳进行了形象营销研究:首先简述了旅游营销的基本理论;然后通过对申遗景点、地方性、旅游者感知、市场竞争替代和已有形象定位的分析确定了河南段洛阳旅游区形象总体定位;基于形象定位就宣传口号、人—地感知形象、人—人感知形象进行了系统设计;最后提出了旅游形象的推广策略.     

东南沿海加工制造业梯度转移分析

本文通过分析东南沿海加工制造业相对于其他地区成本上升的原因,提出其进行产业转移的必要性。然后论述了国内外对产业区域转移问题的研究状况,并提出东南沿海加工制造业转移的理论基础仍然是梯度推移论。所不同的是文章对我国的经济区域和经济梯度进行了再划分,并以此划分为依据对东南沿海加工制造业如何在国内区域间进行梯度转移进行了再思考。