Characterization of 3D pore nanostructure and stress-dependent permeability of organic-rich shales in northern Guizhou Depression,China

The three-dimensional(3D)pore structures and permeability of shale are critical for forecasting gas production capacity and guiding pressure differential control in practical reservoir extraction.However,few investigations have analyzed the effects of microscopic organic matter(OM)morphology and 3D pore nanostructures on the stress sensitivity,which are precisely the most unique and controlling factors of reservoir quality in shales.In this study,ultra-high nanoscale-resolution imaging experiments,i.e.focused ion beam-scanning electron microscopy(FIB-SEMs),were conducted on two organic-rich shale samples from Longmaxi and Wufeng Formations in northern Guizhou Depression,China.Pore morphology,porosity of 3D pore nanostructures,pore size distribution,and connectivity of the six selected regions of interest(including clump-shaped OMs,interstitial OMs,framboidal pyrite,and microfractures)were qualitatively and quantitatively characterized.Pulse decay permeability(PDP)measurement was used to investigate the variation patterns of stress-dependent permeability and stress sensitivity of shales under different confining pressures and pore pressures,and the results were then used to calculate the Biot coefficients for the two shale formations.The results showed that the samples have high OM porosity and 85%of the OM pores have the radius of less than 40 nm.The OM morphology and pore structure characteristics of the Longmaxi and Wufeng Formations were distinctly different.In particular,the OM in the Wufeng Formation samples developed some OM pores with radius larger than500 nm,which significantly improved the connectivity.The macroscopic permeability strongly depends on the permeability of OM pores.The stress sensitivity of permeability of Wufeng Formation was significantly lower than that of Longmaxi Formation,due to the differences in OM morphology and pore structures.The Biot coefficients of 0.729 and 0.697 were obtained for the Longmaxi and Wufeng Formations,respectively.

Performance of Metal and Acid Ions Remediation in Contaminated Soils by Electrokinetics with Chitosan Permeable Reactive Barrier

Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) was used to investigate the performances of metal and acid ions remediation. Adsorption characteristics of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- onto CTS were also conducted. The results showed the sorption of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- on CTS could be well described by Freundlich model. When the CTS dosage is 8 g,the total removal efficiency for Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- is 86. 8%,90. 2%,92. 4%,90. 0% and 82. 5%,respectively. CTS enhanced ions remediation efficiencies significantly compared with the single EK system,especially for SO_4^(2-) and NO_3^-. The results indicate EK/CPRB system is suitable for the remediation of soil contaminated by both metal ions and acid ions.

Method for Tentative Evaluation of Membrane Permeability Coefficients for Sodium and Potassium Ions in Unicellular Organisms

The membrane permeability coefficient for sodium and potassium ions in unicellular organisms can be calculated using the data for cell volume, surface and mean generation time during growth and dividing of cells by binary. Accordingly theory of proposed method, the membrane permeability coefficients for passed trough outer cell membrane sodium and potassium ions, is equal to the volume of unicellular organism divided to product between cell surface and mean generation time of cells. The calculated by this way diapason of values overlaps with experimentally measured diapason of values of permeability coefficient for sodium and potassium ions. The deviation between the theoretically calculated and experimentally measured values of permeability coefficient does not exceed one order of magnitude.

表面修饰模式对Nafion离子选择性影响及在VRFB中的应用（英文）

本文采用壳聚糖-磷钨酸层对Nafion膜表面分别进行单面和双面修饰改性,研究了修饰模式对Nafion膜钒离子渗透率、电导率及离子选择性的影响.结果表明,单面、双面修饰改性均会使Nafion膜的钒离子渗透率显著降低,最高降幅分别达到89.9%(单面修饰)和92.7%(双面修饰);单面、双面修饰改性均会使Nafion膜的电导率下降,但存在明显差异,在相同修饰厚度条件下,双面修饰改性对Nafion膜电导率的影响比单面修饰改性更小.因此,双面修饰复合膜展示出了比单面修饰复合膜更高的离子选择性,并且在修饰层厚度为17μm时达到最大值(1.12×105S·min·cm^(-3)).基于优化的双面修饰Nafion膜的全钒液流电池,在充放电流密度30 mA·cm-2时,库仑效率和能量效率分别达到93.5%和80.7%,并在测试时间内展示出良好的循环稳定性.

Quantitative two/three-dimensional spatial characterization and fluid transport prediction of macro/micropores in Gaomiaozi bentonite

The sealing performance of a bentonite barrier is highly dependent on its seepage characteristics, which are directly related to the characteristics of its pore structure. Based on scanning electron microscopy(SEM) and focused ion beam-SEM(FIB-SEM), the pore structure of bentonite was characterized at different scales. First, a reasonable gray threshold was determined through back analysis, and the image was binarized based on the threshold. In addition, binary images were used to analyze bentonite’s pore structure(porosity and pore size distribution). Furthermore, the effects of different algorithms on the pore structure characterization were evaluated. Then, permeability calculations were performed based on the previous pore structure characteristics and a modified permeability prediction model. For permeability prediction based on the three-dimensional model, the effect of pore tortuosity was also considered. Finally, the accuracy of numerical calculations was verified by conducting macroscopic gas and alcohol permeability experiments. This approach provides a better understanding of the microscale mechanism of gas transport in bentonite and the importance of pore structures at different scales in determining its seepage characteristics.

Pure metal extraction from molten oxide slag by short-circuit galvanic cell

The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]Fe+C saturation|ZrO2(MgO)|(FeO)(slag)|Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.

Pure metal extraction from molten oxide slag by short-circuit galvanic cell

The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]_(Fe+C saturation)[ZrO_2(MgO)|(FeO)_(slag))|Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.

Salt-induced difference between Glycine cyrtoloba and G.max in anti-oxidative ability and K^+ vs. Na^+ selective accumulation

To characterize differences in soybean resistance to salt stress, two soybean species, the wild salt-tolerant soybean Glycine cyrtoloba(serial number ACC547) and the cultivated salt-sensitive soybean G. max(cv. Melrose) were treated with 0, 50, 100, or 150 mmol L-1Na Cl for 5 days. A series of physiological parameters were determined in both shoots and roots, including content of chlorophyll(Chl) and malondialdehyde(MDA); electrolyte leakage(EL); hydrogen peroxide(H2O2) concentration; superoxide oxygen radical(O2-)production rate; activities of several enzymes including superoxide dismutase(SOD),catalase(CAT), and peroxidase(POD); and selective ion(Na+and K+) accumulation. Our results showed that the relative salt tolerance of ACC547 was associated with lower loss of Chl content; lower MDA content, EL, H2O2 concentration, and O2-production rate in both shoots and roots; higher POD activity caused by new isoforms in roots; and higher K+concentration and K+/Na+ratio in shoots. These results suggested that relative lower membrane injury, efficient K+vs. Na+selective accumulation, and newly induced POD isoenzymes are mechanisms of salt tolerance in soybean.

Influence of Mineral Admixtures on Chloride Ion Permeation through Concrete

Through the rapid chloride ion penetration test,the influence of fly ash and slag on chloride ion permeability and microstructure of concrete was studied.The results indicate that the addition of fly ash increases concrete permeability at 28 days.With the slag content of 20% and 30%,the permeability of concrete at 28 days is reduced.The positive effect of slag is due to its relatively stronger pozzolanic reactive ability resulted in the most probable pore size and total porosity decreased.When the slag content reaches 40%,the concrete permeability showes the tendency ofincrease.

Microstructural,magnetic and dielectric performance of rare earth ion(Sm^(3+))-doped MgCd ferrites

The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.03,0.06,0.09,0.12and 0.15)were employed to modify the permeability(μ)and permittivity(ε)of the Mg Cd ferrites.X-ray diffraction,scanning electron microscopy(SEM),vibrating sample magnetometry and vector network analysis techniques were used to characterize the samples.The measurement results reveal that the ferrites processed a saturation magnetization of up to 36.8 emu/g and coercivity of up to 29.2 Oe via the conventional solid-state reaction method.The surface morphology SEM confirms that with increasing Sm^(3+)concentration,the grain shape changes from a polygon to a circle.Moreover,the dielectric permittivity can reach a value of 23.The excellent properties obtained in Sm^(3+)-substituted Mg ferrites suggest that they could be promising candidates for modern high-frequency antenna substrates or multilayer devices.

全钒液流电池离子导电膜的选择性

全钒液流电池(VFB)具有功率大、容量大、效率高、安全性能高的特点,近年来在储能应用方面受到广泛关注。离子导电膜作为VFB的关键组件,存在严重的钒离子交叉污染问题,易造成电池容量损失,降低电池使用寿命,因此深入了解VFB离子导电膜的选择性和质子传导对电池性能具有重要意义。本文综述了VFB中阳离子交换膜、阴离子交换膜、两性离子交换膜以及多孔膜等的研究进展,分析了离子导电膜上钒离子的渗透和质子的传输,重点总结了离子导电膜的改性、超薄复合膜设计、膜内微观结构优化及离子基团功能化对提高离子导电膜选择性和电导率的影响,较为全面地阐述了当前VFB离子导电膜选择性和电导率之间的平衡问题,为开发高性能、低成本、长寿命的离子导电膜,促进其商业化发展提供了参考依据,并展望了基于质子传导机制的氢键网络结构、多孔导电膜、低成本的超薄复合膜以及利用分子动力学模拟离子跨膜来提高VFB离子导电膜选择性的研究方向。

不同螯合剂对褐煤中金属离子浸出效果的实验研究

螯合剂种类的不同,其对金属离子浸出效果也存在差异,为分析螯合剂对贵州地区褐煤中金属离子的浸出效果,选取ASDA,DTPA,IDS和GLDA等共4种螯合剂,开展了浸出效果对比实验,利用电感耦合等离子体质谱仪(ICP)和扫描电子显微镜(SEM)对实验结果进行了表征。结果表明:螯合剂能够将煤体中矿物质解络为游离态,煤体表面孔隙呈现从微孔、小孔向大孔变化的趋势,煤体表面矿物质呈现颗粒数量减少、颗粒体积变小、颗粒形态圆润的特点;ASDA对该煤样中Mg,Al,Fe,Ca,Cu离子具有最佳浸出效果,DTPA对K,Pb离子具有最佳浸出效果。

橡胶混凝土掺杂玄武岩纤维的抗氯离子渗透性能研究

为研究掺杂玄武岩纤维的橡胶混凝土的抗氯离子渗透性能并得出最佳配合比,本文确定橡胶颗粒掺量、玄武岩纤维掺量和玄武岩纤维长度三个因素,进行6 h电通量试验,通过比较电通量的大小对9组混凝土试件的进行研究。实验结果表明:试件电通量随着橡胶颗粒掺量的增加表现出先减小后增大的趋势,且掺量从15%到20%时的增大幅度明显大于掺量从10%到15%时的减小幅度;随着玄武岩纤维掺量的增加,电通量亦先减小后增大,且变化幅度较为平均;随着玄武岩纤维长度的增加电通量持续减小且幅度由小变大。推荐配合比为:橡胶颗粒体积取代率15%、玄武岩纤维掺量0.10%、玄武岩纤维长度18mm。

新型玄武岩纤维束混凝土耐久性能试验

为研究新型玄武岩纤维束混凝土的耐久性能,研究了玄武岩纤维束掺量和长度对混凝土抗氯离子渗透性能、抗冻性方面的影响.结果表明:加入玄武岩纤维束后导致混凝土抗氯离子渗透性能降低,纤维束的掺量越大,氯离子扩散系数越大;玄武岩纤维束掺量相同时,短纤维束混凝土抗氯离子的渗透性优于长纤维束混凝土;掺入玄武岩纤维束有利于提高混凝土的抗冻性能,当掺量达到7.96 kg/m^(3)后,随纤维掺量继续增多,混凝土相对动弹性模量的降幅差别不大,掺量为11.94 kg/m^(3)时,抗压强度损失率最低,为11.4%;玄武岩纤维束掺量相同时,不同长度的玄武岩纤维束对混凝土的相对动弹性模量排序为30 mm>20 mm>40 mm,抗压强度损失率排序为30 mm<20 mm<40 mm.

不同风化带离子型稀土矿浸出前后孔隙结构与渗透性变化特征

离子型稀土矿是典型的风化壳淋积型稀土矿,这类稀土矿浸出前后渗透性变化是反映稀土矿浸出率的重要指标之一,孔隙结构是控制其渗透系数的关键因素。以往对浸出前后稀土矿孔隙结构和渗透性研究主要集中于风化程度和丰度相对较高的全风化带稀土矿,对其他风化带稀土矿的研究较少。随着稀土资源日渐枯竭,其他风化带稀土矿的开发已受到产业部门的高度重视。研究以江西足洞矿区未开采段残积土、全风化带和强风化带内的原状稀土矿试样为研究对象,通过模拟原地浸矿试验,测试其浸出前后渗透系数,采用X射线计算机层析扫描技术获取浸出前后试样结构,采用三维成像技术构建其三维孔隙结构、提取孔隙结构参数,进而定量分析不同风化程度稀土矿浸出前后孔隙结构参数和渗透系数变化规律。结果显示:(1)浸出后,稀土矿渗透系数和孔隙结构参数中的孔隙度、连通性及平均配位数变化率随风化程度降低呈现减小趋势。其中,强风化带稀土矿的渗透系数和孔隙结构参数变化率最小,反映在丰度相近时,强风化带稀土矿较残积土稀土矿的浸出率更高;(2)浸出前后颗粒级配和矿物成分变化特征显示,不同风化带稀土矿浸出前后孔隙结构和渗透性变化率差异的内在机理是长石及云母颗粒分解作用、离子交换作用强度和团粒分散程度的差异以及由此导致的矿物成分和颗粒级配变化程度的差异。研究结果可为类似离子型稀土矿的充分开发利用提供参考。

全氟磺酸树脂和三乙烯基二胺盐的两性离子共混膜的制备及性能研究

离子交换膜作为全钒液流电池(VRB)的核心组成,起到传输离子和阻隔钒离子渗透的作用。将全氟磺酸树脂(PFSA)和三乙烯基二胺(DABCO)盐离子化合物共混,对全氟磺酸树脂进行改性制备了两性离子共混膜。以DABCO-PFSA共混膜为研究基础,采用阴阳离子非共价相互作用的超分子交联方法制备的共混膜可以有效提高膜的综合性能。通过优化共混膜的二组分结构差异合成了聚阳离子PDABCO,并与PFSA共混,聚合物链间超分子交联赋予膜良好的机械性能和稳定性,降低了钒离子渗透,其中PDABCO-PFSA-7.5%膜的钒离子渗透率达到0.25×10^(-6)cm^(2)/min。在VRB测试中,当电流密度为160 mA/cm^(2)时,PDABCO-PFSA-7.5%膜的库伦效率(CE)达到88.43%。

热复合叠片工艺对隔膜透气度的影响

热复合工艺需要对极片和隔膜进行热压,有必要研究隔膜的透气度在热复合前后的变化。探究不同热复合温度(50℃和70℃)和压力(0.10 MPa和0.15 MPa)对三元正极材料(NCM)锂离子电池涂胶隔膜透气度的影响。在相同的热复合工艺条件下,极片粘附情况对隔膜透气度的增值没有明显影响。压力对隔膜透气度的影响要明显高于温度的影响。温度由50℃升高至70℃,隔膜的透气度增值(ΔG)仅增加1 s;压力由0.10 MPa提升至0.15 MPa,ΔG增加约5倍。同时,过大的压力可能会使大尺寸电芯内部靠近极耳侧位置和中间位置隔膜的透气度不一致。

橡胶粉对透水混凝土抗压强度及氯离子渗透性的影响研究

文中对橡胶粉透水混凝土力学性能及耐久性的影响因素进行了研究,重点分析了透水混凝土抗压强度及氯离子渗透系数与橡胶粉粒径、掺量及养护龄期的关系曲线。结果表明,透水混凝土的抗压强度与养护龄期呈正相关关系。与普通混凝土相比,橡胶粉透水混凝土抗压强度有所下降;混凝土抗压强度与橡胶粉粒径呈负相关关系,橡胶粉掺量呈负相关关系;低掺量细粒径的橡胶粉掺入混凝土中,有助于提升其力学性能;橡胶粉氯离子扩散系数与橡胶粉掺量呈负相关关系,但与橡胶粉粒径呈正相关关系。

蒸养制度对掺磷渣粉混凝土强度及氯离子渗透性的影响

选取了两种强度等级的混凝土,研究了不同蒸养温度和蒸养时间对掺磷渣粉混凝土拆模强度、强度发展及氯离子渗透性的影响,并测试了拆模龄期硬化浆体的化学结合水含量。试验结果表明:随着磷渣粉掺量的增加,混凝土的拆模强度和硬化浆体的化学结合水含量逐渐降低。延长恒温蒸养时间和提高蒸养温度均能够显著提高水泥-磷渣粉复合胶凝材料硬化浆体拆模龄期的化学结合水含量,并提高掺磷渣粉混凝土的拆模强度。然而,提高蒸养温度不利于掺磷渣粉混凝土的强度发展及后期的抗氯离子渗透性。延长恒温蒸养时间后,掺磷渣粉混凝土后期能够取得良好的抗压强度和抗氯离子渗透性。

地质聚合物混凝土抗氯离子渗透性能研究进展

地质聚合物混凝土是一种新型绿色建筑材料,氯离子传输是影响其服役寿命的关键因素。本文在介绍地质聚合物混凝土氯离子传输机理的基础上,归纳总结了地质聚合物混凝土抗氯离子渗透性能试验方法的特点和局限性,介绍了地质聚合物混凝土抗氯离子渗透性能的影响因素,并对比了其与普通混凝土氯离子传输机理的区别。文章最后指出高温、冻融等单一因素影响下的地质聚合物混凝土氯离子传输模型、碱掺量和水玻璃模数对地质聚合物混凝土抗氯离子渗透性能的影响,以及氯离子的显色边界浓度的准确性等还有待进一步深入研究。