FREE ENERGY OF FORMATION OF Na_2SnO_3 BY EMF MEASUREMENT USING β-ALUMINA SOLID ELECTROLYTE CELL

A β”/β-Al_2O_3 solid electrolyte was prepared and used in a Na conentration galvanic cell: (-)O_2(in Ar),SnO_2,Na_2SnO_3|β"/β-Al_2O_3]NaCrO_2,Cr_2O_3,O_2(in Ar)(+).The emf measurements were carried out in temperature range of 912—1223 K:E=652.1— 0.2092 T+2.3(mV).Using this equation and cited free energies of formation of NaCrO_2, Cr_2O_3 and SnO_2,the molar free energy of formation of Na_2 SnO_3 may be calculated by ΔG°=-1050+0.2544 T±5.4(kJ mol^(-1)).

Experimental evidence for the formation mechanism of metallic catalyst-free carbon nanotubes

Our work reported that the so-called pure carbon nanotubes(CNTs)can be synthesized without metallic catalyst by chemical vapor deposition(CVD).The as-prepared CNTs have average diameter of 50 nm and length over several microns.Analysis of intermediate objects in the products indicates that their formation mechanism follows the wire-to-tube model.Besides,according to thermodynamic analysis of the driving force combing with experimental results,we find that the thermal gradient can effectively favor the formation of CNTs in our metallic catalyst-free CVD.

Investigation of Formation Process of the Chrome-free Passivation Film of Electrodeposited Zinc

The feasibility was investigated to substitute chrome-free passivation treatment of electrodeposited zinc in a titanium bath for chromate passivation treatment. The formation mechanism of the chrome-free passivation film was further analyzed. The surface mor- phologies and the elemental compositions of the treated samples with varied immersion times were observed by scanning electron mi- croscopy （SEM） and determined by energy dispersion spectrometry （EDS）, respectively. The electrode potential of the sample surface was recorded in the film formation process. The changes of the electrode potential are in accordance with that of SEM and EDS of the sample surface. The results of X-ray photoelectron spectroscopy （XPS） show the chrome-free passivation film composed ofZnO, SiO2, TiO2, Zn4Si207（OH）2, and SrF2. The anode zinc dissolution and the local pH value increase due to the cathode hydrogen ion reduction process result in the formation of the chrome-free passivation film. The macro-images of the chrome-free passivation films formed on electrodeposited zinc show that the color of the film changes from blue to iridescence with the increase of the immersion times.

FREE ENERGIES OF FORMATION FOR ELECTROCHEMICALLOY ALLOYED Y-Cu SYSTEM

The electrochemical alloying of Y-Cu system in molten NaCl-KCl-YCl_3 has been investi- gated.The free energy changes of the formation reactions of the intermetallic compounds,in- cluding YCu_6 ,YCu_4 YCu_2 ,Yfu(973—103 K),were determined by means of electrode potential-time curves of the working electrode after potentiostatic electrolysis.The results in- dicate that the potential-time method is simple and reliable.

Electrochemical determination of Gibbs free energy of formation of magnesium ferrite

The standard Gibbs free energy of formation of magnesium ferrite was determined by means of two types of solid state electrochemical cells： one using MgZr4（PO4）6 （MZP） as the solid electrolyte and the other using CaF2 as the solid electrolyte. The first cell was operated in the range of 950 to 1100 K. The second cell was operated in the range of 1125 to 1200 K. The reversibility of the cell EMFs was confirmed by microcoulometric titration. The Gibbs energy changes of magnesium ferrite relative to component oxides were calculated based on EMF measurements and are given by following expressions, respectively： AG1 = -3579-15 T （J/mol） and AGⅡ =6258-24.3 T （J/mol）. The results obtained from two different cells are consistent with each other. The results also are in agreement with Rao＇ s and Tretjakov＇s data in the measured temperature range. When the Gibbs free energies of formation of MgO and Fe203 were substituted in the reaction, the Gibbs free energies of formation of MgFe204 was obtained in two temperature ranges and the for mations are shown as follows： AG 1Formation =-1427394＋360.5 T （J/mol） and AGⅡ Formition =-1417557＋351.2 T （J/mol）.

The Quasi-Parabolic Regulation of the Standard Free Energies of Formation of Binary Intermediate Compounds

In this paper it has theoretically proved that the relationship of the molar atomic standard free energies of formation of binary intermediate compounds to the molar fraction of component is a quasi-parabola which is called a quasi-parabolic regula- tion.

Theoretical investigation on isomer formation probability and free energy of small C clusters

Molecular dynamics simulations and free energy calculations are employed to investigate the evolution, formation probability, detailed balance, and isomerization rate of small C cluster isomer at 2500 K. For C10, the isomer formation probability predicted by free energy is in good agreement with molecular dynamics simulation. However, for C20, C3o, and C36, the formation probabilities predicted by free energy are not in agreement with molecular dynamics simulations. Although the cluster systems are in equilibrium, detailed balance is not reached. Such results may be attributed to high transformation barriers between cage, bowl, and sheet isomers. In summary, for mesoscopic nanosystems the free energy criterion, which commonly holds for macroscopic systems in dynamic equilibrium, may not provide a good prediction for isomer formation probability. New theoretical criterion should be further investigated for predicting the isomer formation probability of a mesoscopic nanosystem.

STUDY ON THE FORMATION MECHANISM OF MONODISPERSE PARTICLES IN THE EMULSIFIER-FREE EMULSION POLYMEAIZATION OF METHYL METHACRYLATE AND BUTYL ACRYLATE

The formation mechanism of monodisperse polymer latex particles in the emulsifier-free emulsion polymerizationof methyl methacrylate and butyl acrylate with potassium persulfate as initiator was investigated. A multi-step formationmechanism for the monodisperse polymer particles was proposed. The nucleation mechanism is considered to be thecoagulation of the precursor particles by homogeneous nucleation when the primary particles reach a critical size with highsurface charge density and sufficient stability. It had been proved by a special experiment that the early latex particles formedby the coagulation were stable. The primary particles grow by absorbing monomers and radicals in the polymerization systemand then become colloidally unstable again due to the understandable decrease of particle surface charge density, which leadsto the aggregation of the growing particles and the formation of larger latex pedicles therefrom. Aner the nucleation period,the preferential aggregation of the smaller particles in the propagation process leads to the change of the particles towards auniform size and narrower particle size distribution. The coexistence and competition of homogeneous nucleation,coagulation, propagation and aggregation result in the increase of the polydispersity index (U = D_(43)/D_(10)) in the first Stage,then its decrease in the later stage because of the competition of propagation and aggregation, and the gradual formation ofthe monodisperse particles.

Drag-free卫星编队的发展现状和趋势研究

分析了Drag-free卫星编队的发展历程,就动力学建模与系统控制方法进行了综合调研和分析,提出了Drag-free卫星编队的应用前景和需要解决的关键技术,为我国未来空间环境与空间天气等超高精密探测奠定一定的基础.

Electrochemical formation of holmium-cobalt alloys

The electrochemical formation processes of holmium-cobalt alloys on cobaltcathode in molten HoCl_3-KCl were investigated by cyclic voltammetry and open current potential-timecurve alter potentiostatic electrolysis. The structure of Ho-Co alloys' films deposited on cobaltelectrode by potentiostatic electrolysis was characterized by X-ray diffraction. The standard Gibbsfree energies of formation for the intermetallic compounds of Ho and Co were determined. Thediffusion coefficient and diffusion activation energy of Ho atom in the alloy phase were calculatedto be 10^(-10) -10^(-11) cm^2/s and 96.0 kJ/mol, respectively, from the current-time curve atpotential step.

Electrochemical formation of holmium-copper alloys on copper cathode in molten KCl-HoCl_3

Cyclic voltammetry, open circuit potential— time curve after potentiostatic electrolysis and potential step chronoamperometry were used to investigate the electrochemical formation processes of holmium-copper alloys on copper cathode in molten HoCl3-KCl. Intermetallic compounds HoCu5, HoCu4, HoCu2 and HoCu are formed in sequence and then the metallic Ho is deposited when Ho3+ is reduced on copper electrode in molten KCl-HoCl3 at 1066 K. The first charge-transfer reaction is reversible. The structure of holmium-copper alloy film deposited on copper electrode by potentiostatic electrolysis was characterized by X-ray diffraction. The standard free energies of formation for the intermetallic compounds HoCu5, HoCu4, HoCu2 and HoCu are - 95.5, - 92.6, - 73.8 and - 44.0 kJ/mol, respectively. The diffusion coefficient and diffusion activation energy of Ho atom in the alloy are estimated to be 10-10- 10-11 cm2/s and 75.35 kJ/mol, respectively, from the chronoamperometry data.

On the Formation of Abstract Prime Number Theorem

In this paper we prove a zero-free region for L-functions LG（z,Х）. As an application, an abstract prime number theorem with sharp error-term for formations is established.

Occurrence mechanism of lacustrine shale oil in the Paleogene Shahejie Formation of Jiyang Depression, Bohai Bay Basin, China

To determine the occurrence mechanism and mobility of shale oil in the Shahejie Formation in the Jiyang Depression, organic geochemistry analysis, thin-section petrological observation, low-temperature nitrogen adsorption, high-pressure mercury intrusion porosimetry, field emission scanning electron microscopy experiments were conducted on shale samples to reveal its storage mechanism, including pore size, ratio of adsorbed oil to free oil, mobility and its influencing factors, and mode of storage. Residual shale oil is mainly present in pores less than 100 nm in diameter under the atmospheric temperature and pressure. The lower limit of pore size for free oil is 5 nm, and the lower limit of pore size for movable oil occurrence is about 30 nm. The light components, low TOC and high porosity are the main factors contributing to the high proportion of movable oil. Each type of pore can contain residual shale oil, but not all pores have shale oil. Pore connectivity and surface wettability are the determinants of shale oil enrichment degree and enrichment state.

济阳陆相断陷盆地页岩油研究进展

济阳陆相断陷盆地页岩油是现实的资源接替新领域,具有巨大勘探潜力,是胜利油田可持续发展的重要资源基础。结合近年来济阳陆相断陷盆地页岩油地质研究与勘探成效,系统梳理了济阳陆相断陷盆地页岩沉积、成储、成烃及页岩油富集理论认识、配套增产压裂技术等方面的新进展。研究表明:①提出了基于矿物组成、沉积构造、结晶程度和有机质丰度的“四要素三端元”页岩岩相划分方案,揭示了“四古控相”机制,明确了页岩岩相呈“环带状”有序分布。②集成岩心微纳米CT扫描、氩离子抛光扫描电镜、FIB-FESEM、核磁共振冻融、X射线小角散射等页岩多尺度孔缝系统量化表征技术,明确了济阳陆相断陷盆地页岩储集空间孔缝兼顾,以无机孔缝为主,揭示了方解石重结晶、溶蚀作用和伊/蒙混层向伊利石转化作用是最为主要的成储机制,构建了页岩孔缝网络储集模型。③研发了富有机质页岩含油率评价方法,揭示了咸化湖盆富有机质页岩古生产力高、早生、早富特点,初步估算济阳陆相断陷盆地页岩油资源量超过1010t。④纹层/层状页岩岩相成烃、成储时空耦合控制了页岩油富集,表现为“咸化源岩早生、无机孔缝储集、微观源储一体、二元耦合富集”模式。⑤创建了陆相断陷盆地页岩油勘探“四性”“四定”综合评价体系及目标优选流程。⑥研发了适合济阳陆相断陷盆地页岩的“组合缝网压裂”“水平井多级分段”增产压裂技术。结合胜利油田实际情况,确立了“主力洼陷增储上产、富油小洼陷探索新阵地、外围小洼陷落实资源、兼顾优化矿权”的勘探思路,有序推进济阳陆相断陷盆地页岩油规模增储建产,相关成果认识与配套技术对同类油田的页岩油勘探开发具有一定的借鉴和参考意义。

The study of formulation and performance of formate drilling and completion fluid system

Formate drilling and completion fluid system is a new type of clean organic salt brine system which has been developed from inorganic salt brine drilling fluid system. It is beneficial to protecte and find hydrocarbon reservoir. Due to the solid free system, the damage of solid phase particles on reservoir, especially low permeability oil and gas layer, can be greatly eliminated, at the same time, drilling fluid and completion fluid have greater compatibility. It will avoid that precipitation which is not compatible with drilling and completion fluid and generates damages on reservoir. And because mud cake of the solid free system is thin and resilient, it is conductive to improve cementing quality greatly. Experiments show that the formate drilling and completion system has good rheological property, strong inhibition ability, good lubricating performance, good compatibility with reservoir rocks and formation water at high temperature.

稀土镧对Q450NQR1铁路车厢用钢中夹杂物生成的影响

文章通过采用感应炉试验和热力学计算研究钢中镧元素含量对钢中夹杂物的影响,得出在Q450NQR1铁路车厢用钢的钢液热力学条件下,首先形成的是稀土硫氧化物,然后是稀土镧的铝酸盐、氧化物、碳化物、硫化物,最后是反应趋势较小的镧-硅和镧-铝金属间化合物以及稀土氢化物。通过Ohnaka偏析模型的计算得出,LaAs和LaP夹杂物可以在凝固过程中产生。

基于LabVIEW的无模型自适应控制算法实现与应用

为了有效地将无模型自适应控制算法(MFAC)应用于实际场景,该文研究LabVIEW开发环境中实现基于紧格式动态线性化的无模型自适应控制(MFAC-CFDL)。实验结果表明,对于相同的被控对象,LabVIEW实现与Matlab的仿真运行结果一致,证明该方法准确性。进一步与传统的PID控制方法相比较,MFAC-CFDL显示出更强的鲁棒性,并能保证闭环系统的稳定性以及输出误差跟踪的收敛性,通过实验说明该方法工程实践应用有效性和可行性。

工业热过程中无意生成持久性有机污染物的自由基转化机制

掌握无意生成持久性有机污染物(unintentionally produced persistent organic pollutants,UPOPs)的生成机制对于其在典型工业热过程中的源头控制具有重要意义,现有对二噁英等UPOPs生成机制的研究主要是基于反应后稳定化合物和目标同类物分布的检测,缺乏对自由基中间体的研究.环境持久性自由基(environmentally persistent free radicals,EPFRs)是一类新的环境污染物,其半衰期可达数月,可在环境样品以及二噁英生成过程中检出.近年来EPFRs被认为是UPOPs生成的重要自由基中间体.本文对UPOPs生成过程中前驱体种类、金属化合物、温度、反应气氛等对EPFRs生成特性的影响作用进行了综述,分析了前驱体生成UPOPs过程中同种或不同种EPFRs的转化路径.此外,基于现有UPOPs源头阻滞技术,提出了UPOPs与EPFRs协同控制的潜在方法.

四川盆地南部下寒武统筇竹寺组页岩孔隙结构特征与页岩气赋存模式

近年来,四川盆地南部地区(以下简称川南地区)下寒武统筇竹寺组页岩气勘探开发取得了实质性的突破,但是,关于筇竹寺组页岩气储层孔隙结构特征及其对页岩气赋存模式影响的研究还较为薄弱。为此,以川南地区W207井筇竹寺组页岩为例,以总有机碳含量(TOC)不小于1.0%为界,将筇竹寺组页岩划分出4个高有机碳页岩层段(H1—H4层),并基于大视域扫描电镜、流体注入法孔隙定量表征、三维分子结构建模与分子模拟等方法,研究了不同富有机质层段页岩孔隙特征,并着重分析了H3层页岩孔隙发育特征与页岩气赋存模式。研究结果表明:(1)筇竹寺组页岩纵向上孔隙发育差异较大,其中H3层页岩孔隙系统最为有利,发育粒缘缝—有机质纳米连通孔隙—有机质基质分子内孔隙3级孔隙网络,其矿物粒缘缝与有机质纳米孔隙提供了较大的游离气储集空间,页岩有机质分子结构中普遍发育微孔,提供了较大的吸附空间;(2)微孔对总吸附量的贡献随压力增高而降低,但在30.0 MPa时仍贡献了56%以上的总吸附气量;(3)高温高压下(30.0 MPa、70℃),页岩中游离气甲烷含量占总含气量的57%,当压力由30.0 MPa降低至16.5 MPa,游离气贡献总开采气量超过80%;(4)粒缘缝、有机质纳米连通孔隙和有机质基质分子内孔隙良好的配置关系为页岩气富集及开发提供了良好的连通体系,远离风化壳的超压层段有利于页岩孔隙发育。结论认为,川南地区筇竹寺组H3层页岩孔隙系统发育,具备页岩气高产地质条件,是筇竹寺组下一步重点关注层段,在此基础上寻找远离风化壳、孔隙发育的超压页岩储层是筇竹寺组选区选层的关键。

准噶尔盆地玛湖凹陷风城组泥页岩生物标志化合物特征与赋存状态研究

准噶尔盆地玛湖凹陷二叠系风城组泥页岩不同层段生物标志化合物特征与赋存状态特征认识较为薄弱,通过采用岩石热解、气相色谱—质谱、荧光薄片和氩离子抛光电镜等实验技术,厘清不同层段烃源岩物质基础、生物标志化合物分布特征及意义、不同赋存状态页岩油,对玛湖凹陷下一步勘探部署具有重要意义。玛湖凹陷风城组泥页岩主要为中等—好烃源岩,有机质类型为Ⅱ型,处于成熟演化阶段;生物标志化合物组成特征表明具有高丰度的Pr和Ph、β-胡萝卜烷及C_(29)重排甾烷,C_(27)-C_(28)-C_(29)规则甾烷呈反“L”型分布,指示有机质以藻类等低等水生生物贡献为主;较低的Pr/Ph比值以及较高的伽马蜡烷指数,反映出沉积环境主要为咸化的还原环境;C_(31)αβ22S/(22S+22R)、C_(29)M/C_(29)H和C_(29)ββ/(ββ+αα)等藿烷类和甾烷类成熟度参数表明烃源岩处于成熟阶段。另外,风城组二段泥页岩相对于风一段、风三段具有更大的生烃潜力,具备更好的烃源岩物质基础,同时C_(20)/C_(23) TT、C_(21)/C_(23)TT、Ga/C_(30)H等生物标志化合物相关参数指示风二段藻类等贡献较多,更偏还原和咸化的环境;结合风二段以游离赋存状态为主,认为烃类赋存于粒间孔和粒内孔中。风二段有利于页岩油富集与保存,展现出更好的页岩油勘探开发前景。