长庆陇东地区油井压裂返排液配钻井液研究与应用

针对长庆陇东地区压裂返排液总量大、资源化利用率低的技术难题，以“减量化、资源化”为核心，通过对陇东油井区域4种典型压裂返排液样品的基本性能、离子成分、生化指标、发泡性能等分析研究，确定出返排液配制钻井液的主要影响因素。针对研究得出的影响因素开展了返排液预处理除砂设备、杀菌剂、抑泡剂及离子去除剂的优选评价等，同时结合长庆油气田现场生产实际确定出返排液预处理工艺技术流程，并在水资源短缺的长庆陇东致密油大井组水平井华H20-*平台完成2口井压裂返排液预处理及配制钻井液技术研究先导性试验。现场应用结果表明，预处理后返排液配制的钻井液同生产用水配制的钻井液性能基本接近，密度为1.25~1.30 g/cm3，表观黏度损失率可控制在15.0%以内，试验井段井壁稳定、钻井液滤失量、发泡性能可控，能够很好地满足现场钻井液使用要求。该研究及应用为压裂返排液配钻井液技术的推广及提高水资源综合利率奠定基础。      

长庆气田小井眼钻井液技术研究与应用

为解决长庆气田小井眼施工中存在的井漏、地层自呼吸、井壁失稳、携岩困难、电测成功率低等问题，从水力参数、岩屑清除和钻井液体系入手，在兼顾降低循环压耗和提高环空净化能力的同时，设定合理的泵排量，以此预防井漏、避免地层自呼吸现象；从新的实验评价方法入手，结合小井眼钻井液施工特点，优选出复合抑制剂CQFY作为主抑制剂、天然高分子降滤失剂NAT20作为降滤失剂、无荧光白沥青NFA-25作为封堵剂，确定钻井液体系配方。2018年至今施工的φ165.1 mm井眼和φ152.4 mm井眼均使用了该技术。现场应用表明，该技术可有效保证井壁稳定，井径规则，并可预防井漏，避免地层自呼吸现象，提高了钻速，电测成功率高。完成φ165.1 mm井眼235口井，电测成功率为84.7%，φ152.4 mm井眼7口，电测成功率为100%，取得了较好的应用效果。      

Cd-substituted Mg composites with dual-equivalent permeability and permittivity for high-frequency miniaturization antennas

Spinel Mg ferrites Mg_1-xCd_xCo_0.05Fe_1.95O₄ (x=0.0, 0.2, 0.3 and 0.4) as potential agents for the miniaturization of high frequency antennas are presented. All the synthesized compositions were experimentally revealed to possess pure spinel phase. Dual-equivalent permeability and permittivity (μ'≈26, ε'≈25, x=0.3 and μ'≈29, ε'≈28, x=0.4) from 5 to 100 MHz can be achieved by introducing Cd²⁺ ions, yielding large miniaturization factors of up to 25 and 28. To figure out the effects of Cd²⁺ ions substitution on magnetic and dielectric properties, the change in microstructure is mainly investigated. Meanwhile, enhanced magnetic properties including upward saturation magnetization (Ms) (approximately 47.60 emu/g) and reduced coercivity (approximately 54.22 Oe) are obtained due to increased grain size and denser microstructure arrangements reflected from scanning electron microscopy images. With low magnitude order of magnetic and dielectric losses factors (tanδ_ε reaches 10^-4, tanδ_μ reaches 10^-2), the composites can potentially exhibit high operating efficiencies at high frequencies.     

轻质碳酸钙加填量对PCCP/LCP-1复合材料气体吸附性能的影响

利用原位生长法制备了轻质碳酸钙(PCC)加填的植物纤维纸基(PCCP)/金属有机骨架化合物(MOFs,即Zn2(BTC)4,标记为LCP-1)复合材料(PCCP/LCP-1),探讨了PCC加填量对复合材料气体吸附性能的影响;采用傅里叶变换红外光谱仪(FT-IR)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、热重分析仪(TGA)和氮气吸附法(BET)研究了LCP-1与植物纤维的键合方式以及复合材料的表面形貌、比表面积、热稳定性和吸附行为。结果表明,LCP-1与植物纤维之间以酯键结合,PCC加填量的增加可使纸张纤维网络体系暴露出更多的游离羟基,有利于提高LCP-1在PCCP表面的沉积率。此外,PCC的位阻效应降低了LCP-1在PCCP表面的生长空间,导致LCP-1尺寸变小。BET实验表明,与未添加PCC的复合材料相比,添加PCC可显著提高复合材料的吸附性能,且随着PCC加填量的增加,复合材料的氮气吸附量也逐渐提高。     

基于机器视觉的苹果在线分级

通过CCD相机动态采集苹果两个面的实时图像,提出了泛洪填充+自适应Ostu阈值分割算法提取苹果的轮廓,采用最小外接圆法对苹果上表面图像进行处理得到苹果果径,采用最小外接矩形法对苹果侧表面图像进行处理提取苹果果形特征;将图像进行RGB到HSV空间转换,提取苹果的着色度、果锈,以及疤痕特征,采用基于改进粒子群算法的SVM决策树的分类方法进行苹果的分级。结果表明,该方法对特级果、一级果、二级果和等外果的识别准确率分别达96%,94%,98%,98%,分级速率达4个/s,可以满足苹果在线分级的要求。     

Thermal annealing characteristics of solar selective absorber coatings based on nano-multilayered MoOx films

Designing double metal-dielectric (cermet) solar selective absorber coatings (SSACs) often requires complex co-sputtering techniques with multiple targets. This inevitably limits the simple and low-cost industrial fabrication. Here, we develop novel nano-multilayered MoO_x-based SSACs by simple and stable one-step reactive magnetron sputtering process using single molybdenum target. The proposed multilayer SSACs exhibit good solar absorptance of 0.93 and low thermal emittance of 0.06. Owing to the temperature-induced oxygen diffusion and oxidation phenomenon the as-sputtered SSACs have a poor thermal tolerance under air atmosphere, and after annealing at 200 °C for 150 h, the resulting absorptance is diminished from 0.93 to 0.90. However, the optical performance of the annealed SSAC is relatively stable in high-vacuum environment, even after annealing at 450 °C for 200 h, it still displays an ideal spectral selectivity of 0.92/0.07. With above properties, the resulting MoO_x-based SSAC is a promising absorber for enduring thermal harvesting in solar vacuum collectors.     

The relationship between enhanced dielectric property and structural distortion in Ca doped Ba2NaNb5O15 tungsten bronze ceramics

The relationship between enhanced dielectric property and structural distortion in tungsten bronze structure ceramics was discussed in this work. The ceramics with the composition of (Ba_1-xCa_x)₂NaNb₅O₁₅ (x = 0, 0.1, 0.2, 0.3, 0.4) were fabricated via conventional solid-state method. All ceramics were pure without secondary phase and the distinct lattice distortion in structure was testified by Rietveld XRD refinement. Compared with the un-doped composition, the maximum polarization and energy storage density were strongly enhanced according to the ferroelectric property measurements, which were contributed to the distortion of NbO₆ octahedron induced by the variation of ionic radius. The actually pulsed charge-discharge property of x = 0.3 ceramic was tested, whist excellent power density (P_D = 35.106 MV/cm³) and discharge energy density (W_d = 0.29 J/cm³) were obtained at 100 °C under 120 kV/cm, revealing the potential for application of Ba₂NaNb₅O₁₅ system-based ceramics in harsh environment.     

Synthesis and electrochemical performance of three-dimensional ordered hierarchically porous Li4Ti5O12 for high performance lithium ion Batteries

In this work, a three-dimensional ordered hierarchically porous (3DOHP) Li₄Ti₅O₁₂ that possesses inner-particle mesopores resulting from a soft template method and a three-dimensional ordered macroporous (3DOM) Li₄Ti₅O₁₂ using polystyrene spheres as a hard template have been synthesized. Both 3DOM Li₄Ti₅O₁₂ and 3DOHP Li₄Ti₅O₁₂ have ordered macropores and interconnected skeletons with a regular periodicity revealed by SEM and TEM observations. The specific surface area of 3DOHP Li₄Ti₅O₁₂ is up to 135 m² g^?1 which is much higher compared with that of 3DOM Li₄Ti₅O₁₂ because of the existence of inner-particle mesopores. Attributed to the higher surface area and smaller crystal grain size, more excellent cycle performance and rate capability are obtained for 3DOHP Li₄Ti₅O₁₂ compared to 3DOM Li₄Ti₅O₁₂. In addition, the hierarchically porous structure of 3DOHP Li₄Ti₅O₁₂ can meet rapid insertion and deinsertion of lithium ion even at extremely high rate. It is apparent that 3DOHP Li₄Ti₅O₁₂ has a lower total resistance and faster Li⁺ diffusion coefficient compared to 3DOM Li₄Ti₅O₁₂ according to electrochemical impendence spectroscopy analysis.     

Enhanced relative permittivity in niobium and europium co-doped TiO2 ceramics

The appearance of colossal permittivity materials broadened the choice of materials for energy-storage applications. In this work, colossal permittivity in ceramics of TiO₂ co-doped with niobium and europium ions ((Eu_0.5Nb_0.5)_xTi_1-xO₂ ceramics) was reported. A large permittivity (ε_r ～ 2.01?×?10⁵) and a low dielectric loss (tanδ ～ 0.095) were observed for (Eu_0.5Nb_0.5)_xTi_1-xO₂ (x?=?1%) ceramics at 1?kHz. Moreover, two significant relaxations were observed in the temperature dependence of dielectric properties for (Eu, Nb) co-doped TiO₂ ceramics, which originated from defect dipoles and electron hopping, respectively. The low dielectric loss and high relative permittivity were ascribed to the electron-pinned defect-dipoles and electrons hopping. The (Eu_0.5Nb_0.5)_xTi_1-xO₂ ceramic with great colossal permittivity is one of the most promising candidates for high-energy density storage applications.     

Enhanced energy storage properties of Ba0.4Sr0.6TiO3 lead-free ceramics with Bi2O3-B2O3-SiO2 glass addition

In this study, we present an effective strategy to enhance the energy storage properties of Ba_0.4Sr_0.6TiO₃ (BST) lead-free ceramics by the addition of Bi₂O₃-B₂O₃-SiO₂ (BBS) glass, which were prepared by the conventional solid state sintering method. The phase structure, microstructure and energy storage properties were investigated in detail. It can be found that the Ba_0.4Sr_0.6TiO₃-x wt%(Bi₂O₃-B₂O₃-SiO₂) (BST- x wt%BBS, 0 ≤ x ≤ 12) ceramics possess large maximum polarization (P_max), low remanent polarization (P_r) and slim polarization electric field (P-E) hysteresis loops. The breakdown strength (BDS), recoverable energy storage density (W_rec) and energy storage efficiency (η) are enhanced obviously with the addition of BBS glass. The BST-9 wt%BBS ceramic is found to exhibit excellent energy storage properties with a W_rec of 1.98 J/cm³ and a η of 90.57% at 279 kV/cm. These results indicate that the BST-x wt%BBS ceramics might be good candidates for high energy storage applications.