Preparation and thermal-insulating properties of Ce-doped ZrO2 hollow fibers derived from a metaplexis template

ZrO₂ is an attractive thermal-insulating material for high-temperature applications owing to its low heat conductivity and corrosion resistance. The seed hair in metaplexis is a natural fiber with a hollow structure that endows it with outstanding thermal-insulating properties. In this paper, we describe a procedure for preparing CeO₂-stabilized tetragonal ZrO₂ hollow fibers obtained by imitating a metaplexis template. The metaplexis fibers were first immersed in a mixed solution of ZrOCl₂ and Ce(NO₃)₃ to prepare the precursor fibers. The fibers thus produced were subsequently dried in vacuum and sintered under the standard atmospheric pressure in aerobic atmosphere at temperature values of 900, 1100, and 1300°C. The microstructures, phase composition, pore size distribution, and thermal conductivities of the fibers were investigated. Results showed that the Ce-stabilized ZrO₂ fiber inherited the hollow structure of the metaplexis, consequently exerting a significant effect on its thermal-insulating properties. Compared to conventional ZrO₂ fibers, the thermal conductivities of Ce-stabilized ZrO₂ fibers can decrease by approximately 12%-24.3%.     

外表面不同孔结构的阳极氧化铝模板的自组织制备

经二次阳极氧化制备了外表面不同孔结构的阳极氧化铝模板.用场发射扫描电镜(FE-SEM)对其形貌进行表征,发现在直接阳极氧化的铝箔的外表面自组装形成了规则的六方形的纳米孔,而在去除铝基、扩孔的另一外表面则形成了规则的圆形的纳米孔,外表面纳米孔的平均直径大约为80nm,孔间距大约为110nm,孔密度约为2.5×10n cm-2.在模板的内部形成相互平行且垂直于AAO模板外表面的纳米管的阵列结构,纳米管的平均直径大约为80nm;AAO模板的厚度大约为10/zm.粉末X射线衍射(XRD)表明模板具有非晶态的结构.记录了阳极氧化过程中的电流一时间曲线,探讨了自组织孔洞的形成机理,提出了新型阳极氧化铝模板制备纳/微米结构材料模拟应用.     

Flux blended synthesis of novel Y2O3:Eu3+ sensing arrays for highly sensitive dual mode detection of LFPs on versatile surfaces

In the present communication,various fluxes blended Y_2 O_3:Eu~(3+)(5 mol%) nanopowders(NPs) were successfully fabricated by solution combustion method.PXRD pattern confirms body-centered cubic structure of the prepared samples.Energy band gap(Eg) of the fabricated products was estimated and is found to be in the range of 3.13-3.32 eV.Photoluminescence(PL) emission spectra exhibit sharp and intense peaks at ～579,592,614,657,704 nm corresponding to ~5 D_0→~7 F_J(J = 0,1,2,3 and 4) transitions of Eu~(3+) ions.Significance of fluxes for enhancing the PL emissions was extensively studied.Photometric studies of the prepared samples are located in pure red region.Optimized NPs were explored as a novel sensing agent for visualization of latent fingerprints(LFPs) on various surfaces including porous,semiporous and non-porous surfaces followed by powder dusting technique.Various experiments including aging,temperature,scratching and aquatic fresh water treatment tests were performed to evaluate applicability of the fabricated NPs.Visualized LFPs exhibit well defined ridge details including most authenticated sweat pores are also revealed with high sensitivity,selectivity,little background hindrance and less toxicity.Aforementioned results evidence that the method and fabricated NPs can be considered to be simple,rapid and economical and provide novel sensing platform for LFPs visualization in prospective forensic applications.     

Production and characterization of durable self-cleaning and engineering porous Al2O3/CaAl12O19 ceramic membranes

The rapid development of engineering filtering process suggests that it is imperative to produce membrane substrates with a fine pore size, high gas permeation, and antifouling properties for efficient and long-term application. This study reports on a novel fabrication method of a porous Al₂O₃/CaAl₁₂O₁₉ ceramic membrane substrate by a direct foaming method combined with cement solidification and tape-casting technology. The microstructure of the produced ceramic membrane consisted of pores with a size of 50-150 μm, which were interconnected with each other with a large number of small filtering functional pores of <10 μm. By increasing the amount of the foaming agent, the porosity of the porous Al₂O₃/CaAl₁₂O₁₉ ceramic membranes was tailored from 64.8% to 80.5%, and the bending strength decreased from 32.1 ± 1.0 to 9.6 ± 0.9 MPa, respectively. The sintered hydrophilic ceramic substrate was successfully modified to a hydrophobic one (with water contact angles of 143°) by pyrolysis of dimethyldichlorosilane and dichloromethylsilane. The resultant membrane displayed high chemical stability and self-cleaning features. The membrane with a porosity of 64.8% had a N₂ permeation of 3.0 (±0.5) × 10⁷ L m⁻² h⁻¹ at 0.5 bar and a water flux which could be totally suppressed at a liquid entry pressure of 0.45 bar.     

砂砾岩储集层微观非均质性定量评价——以柴达木盆地昆北油田为例

砂砾岩储集层岩石颗粒分选差,孔隙结构复杂,存在类似双重孔隙介质特征,孔隙结构微观非均质性较强。柴达木盆地昆北油田古近系路乐河组储集层即为此类砂砾岩储集层,毛管压力曲线无“平台”部分,孔喉大小分布呈明显的多峰特征,具有“大孔-小孔”似双重孔隙介质特征。通过对储集层岩石毛管压力数据的分析,计算得出“主要流动空间百分数”,可以定量表征此类砂砾岩储集层孔隙空间中大孔道和小孔道所占比例,进而定量评价此类储集层的微观孔隙结构非均质性。结果表明：路乐河组砂砾岩储集层中由“大孔”组成的孔隙空间所占比例较少,平均约占全部孔隙空间的1/3,对储集层渗透率的贡献却达到了95%,而“小孔”虽占据了约2/3的孔隙空间,但对渗透率的贡献仅为5%,说明储集层微观孔隙结构非均质性较强。     

基于二氧化碳和液氮吸附、高压压汞和低场核磁共振的煤岩多尺度孔径表征

煤岩系统内发育有nm~mm级的多种孔裂隙,系统表征其内部孔隙结构特征对查明煤岩物性和煤层气产出规律极为重要。基于对鄂尔多斯盆地东缘不同地区的系统采样,采用低温二氧化碳和液氮吸附、高压压汞和低场核磁共振系统表征了研究区煤岩的孔径结构。结果表明,二氧化碳吸附适用于0.6~1nm的微孔,液氮的主体适用范围在1~20nm左右,压汞可表征18nm以上的孔径。根据进汞饱和度、退汞效率和孔隙度将研究区煤岩划分为7个小类,并对应分析了进汞-退汞曲线特征。基于核磁共振表征了不同镜质体反射率和不同埋深的煤岩孔径大小的分布和连通性,随反射率升高和埋深加大,微小孔的比例呈现增加的趋势。相关成果对解释东缘范围内的煤储层物性特征,系统查明不同尺度煤岩孔径分布特征具有一定的支撑作用。     

Al基金属玻璃涂层孔隙特性的精确表征及对其腐蚀行为的影响规律

选用Al86Ni6Y4.5Co2La1.5铝基非晶粉体材料,采用自研的低温超音速喷涂系统,在ZM5表面制备了具备良好耐蚀性能的铝基金属玻璃涂层,分析了涂层的孔隙类型及成因,优选出X射线三维成像法测定了涂层孔隙率,表征了涂层孔隙几何特征,阐明了孔隙对涂层腐蚀行为的影响规律。结果表明,涂层主要包含宏观型、层间型、微球型和微细型四类常规孔隙缺陷;涂层孔隙率基本小于1%且沿厚度方向上变化不大,孔隙呈近球形,尺寸均小于10μm,尤以5μm左右居多;不同孔隙率的涂层均呈现出较宽的自钝化区间,自腐蚀电位较为接近,腐蚀电流密度与孔隙率正相关,大尺寸、贯穿型、边界处的个别特殊孔隙是导致涂层腐蚀失效的根本原因。     

沸石类矿物成因及其对储层储集性能的影响

近年来,国内油气田的勘探开发中发现了大量沸石类矿物,为了研究沸石类矿物成因及其对储层的影响,对国内外主要沉积盆地发育的沸石种类、发育的条件及控制因素、沸石类矿物对储层的影响进行了综述.结果表明:①含油气沉积盆地中主要发育方沸石、片沸石、浊沸石和斜发沸石.②盆地中沸石成因可以分为火山玻璃质水岩反应、湖相热水沉积以及盐碱性...     

气相转移法制备多孔双相沸石复合物

采用气相转移法制备了同时含有Y和ZSM-5沸石的双相沸石复合物。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、N₂吸附-脱附和骨架红外(FT-IR)等手段对合成的样品进行了表征。结果表明, 合成的样品受Y型沸石的添加量、干胶制备条件和气相转移法转化条件的影响; 水热预处理后的ZSM-5沸石前驱体中具有ZSM-5沸石的骨架特征振动峰, 归结于ZSM-5沸石晶核或微晶的形成, 这有利于在气相转移法转化过程中引导或促使体系向ZSM-5沸石相的转变, 并有利于抑制ZSM-35杂晶的形成; Y型沸石在蒸汽处理过程中的脱铝过程导致合成的沸石复合物具有介孔结构。     

鄂尔多斯盆地下寺湾龙咀沟地区长2 油层组成岩作用及对储层的影响

利用铸体薄片鉴定、X 射线衍射、镜质体反射率、扫描电镜及阴极发光等资料,对鄂尔多斯盆地下 寺湾龙咀沟地区长2 油层组储集层的岩石学、储层物性、成岩作用、成岩阶段及储层微观结构特征进行 了分析和评价。结果表明：下寺湾龙咀沟地区长2 油层组主要发育中-细粒岩屑长石砂岩;孔隙类型主 要为粒间孔隙;喉道类型主要为点状喉道;成岩作用类型主要为压实作用、胶结作用、交代作用和溶蚀作 用;在孔隙演化过程中,压实作用对储层物性的破坏性最强,其次为胶结和交代作用,溶蚀作用对储层孔 隙的改善效果明显。结合流体包裹体及镜质体反射率等分析资料,得出龙咀沟地区长2 油层组砂岩现 今处于中成岩A 期演化阶段。