Oxidation and ablation behaviour of multiphase ultra-high-temperature ceramic Ta0·5Zr0·5B2–Si–SiC protective coating for graphite

To provide reliable oxidation protection for carbon materials under harsh high-temperature aerobic environments, a dense monolayer-multiphase ultra-high-temperature ceramic Ta_0·5Zr_0·5B₂–Si–SiC (TZSS) coating was fabricated by a combination of dipping and in-situ reaction. The oxidation resistance of the TZSS coating was investigated at 1923 K in air. The results indicated that the TZSS coating could offer at least 70 h of oxidation protection for the matrix material. The synergistic oxygen-blocking effect of the thick oxide layer formed during the oxidation test and the inner coating, played a key role in the oxidation protection process. These were responsible for the excellent oxidation resistance ability of the TZSS coating. Additionally, the ablation performance of the TZSS coating was also investigated under increased heat flux from 2.4 MW/m² to 4.2 MW/m². The ablation behaviours changed from the oxidation and evaporation of coating materials to mechanical scouring, corresponding to increased mass and linear ablation rates. Interestingly, after ablation for 40 s under a heat flux of 4.2 MW/m², a new microstructure composed of “lath-like” Ta₄Zr₁₁O₃₂ solid solution grains was found in the ablation center. This oxide layer possessed few micropores, which could provide reliable protection for the matrix material under ultra-high-temperature oxygen-containing airflow erosion, thus preventing further damage to the composite.     

临兴区块新型储层保护钻井液技术研究与应用

临兴区块地层非均质性强,具有低孔、低渗、低温、低压的特点,需要后期压裂改造,才能实现工业化气流.随着该区域的钻井数量逐渐增多,储层伤害问题日益突出,笔者对地层进行了敏感性分析,在此基础上,研制了超双疏剂,并对其性能进行了评价.结果表明:超双疏剂能够使岩心孔喉表面润湿性由亲水亲油向疏水疏油转变,有效降低低渗储层发生自吸水锁概率,达到保护储层的目的;同时,3％质量分数的超双疏剂比传统的抑制剂KCl和聚醚胺等具有更好的抑制性能.现场应用表明,加入超双疏剂后的钻井液黏度低、切力高、老化前后性能稳定,应用双疏钻井液体系后现场平均机械钻速提高32.33％,井眼扩大率降低33.89％,作业井日产量平均在35973.5 m3/d.     

A microfluidic approach for development of hybrid collagen-chitosan extracellular matrix-like membranes for on-chip cell cultures

To advance organ-on-a-chip development and other areas befitting from physiologically-relevant biomembranes,a microfluidic platform is presented for synthesis of biomembranes during gelation and investigation into their role as extracellular matrix supports.In this work,high-throughput studies of collagen,chitosan,and collagen-chitosan hybrid biomembranes were carried out to characterize and compare key properties as a function of the applied hydrodynamic conditions during gelation.Specifically,depending on the biopolymer material used,varying flow conditions during biomembrane gelation caused width,uniformity,and swelling ratio to be differently affected and controllable.Finally,cell viability studies of seeded fibroblasts were conducted,thus showing the potential for biological applications.     

一种新型10 kV双环网结构

通过比对国内外配电网网架情况,提出一种新的10kV双环网结构,并应用在实际案例中,结果表明该结构在满足负荷、可靠性的要求下,能够有效降低线路半径、节约投资.     

Investigation of alkaline complexant on ethanol synthesis from syngas over slurry CuZnAlOOH catalyst

A series of alkaline complexants promoted slurry CuZnAlOOH catalysts were prepared by a complete liquid-phase method. These catalysts were applied in a slurry bed reactor to selectively convert syngas into ethanol and higher alcohols (HAs). Herein, we showed that the addition of alkaline complexant remarkably enhanced both CO conversion and selectivity toward to ethanol and HAs in terms of ternary CuZnAlOOH catalyst. Besides, the formation of dimethyl ether (DME) was significantly suppressed. Interestingly, different from the traditional alkalis modified copper-based catalysts, these catalysts promoted by alkaline complexants mainly increased selectivity for ethanol, while not isobutanol. It also reduced the deactivation rate of the catalysts. These catalysts were comprehensively characterized by XRD, H₂-TPR, NH₃-TPD-MS, N₂ adsorption, FT-IR, XPS and TEM techniques. It was found that the increase of ethanol selectivity was related to the decrease of catalyst surface acidity, while the decrease of surface Cu⁺/(Cu⁰+Cu⁺) was regarded to the main reason for the catalysts deactivation. This paper showed that the introduction of alkaline complexants into Cu-based catalysts exhibited the potentiality to improve the stability and the yield of ethanol in a slurry bed reactor.     

施工现场标准化管理探讨

通过对神华宁煤400万t/a煤化工副产品深加工综合利用项目60万t/a聚丙烯装置施工作业现场的标准化研究,从技术团队的选择、计划进度控制、现场施工管理、文档资料规范等几个方面,探讨施工作业现场标准化作业的方法,为提高施工作业现场管理提供一些有益的建议。     

Fabrication and Thermal Dissipation Properties of Carbon Nanofibers Derived from Electrospun Poly(Amic Acid) Carboxylate Salt Nanofibers

Polyimides (PIs) possess excellent mechanical properties, thermal stability, and chemical resistance and can be converted to carbon materials by thermal carbonization. The preparation of carbon nanomaterials by carbonizing PI‐based nanomaterials, however, has been less studied. In this work, the fabrication of PI nanofibers is investigated using electrospinning and their transformation to carbon nanofibers. Poly(amic acid) carboxylate salts (PAASs) solutions are first electrospun to form PAAS nanofibers. After the imidization and carbonization processes, PI and carbon nanofibers can then be obtained, respectively. The Raman spectra reveal that the carbon nanofibers are partially graphitized by the carbonization process. The diameters of the PI nanofibers are observed to be smaller than those of the PAAS nanofibers because of the formation of the more densely packed structures after the imidization processes; the diameters of the carbon nanofibers remain similar to those of the PI nanofibers after the carbonization process. The thermal dissipation behaviors of the PI and carbon nanofibers are also examined. The infrared images indicate that the transfer rates of thermal energy for the carbon nanofibers are higher than those for the PI nanofibers, due to the better thermal conductivity of carbon caused by the covalent sp² bonding between carbon atoms.