具有吸附作用的酸液缓速外加剂FL-1的研制

针对目前常规酸液缓速外加剂普遍存在泵入地层困难,二次伤害大等问题,从分子结构出发,合成了一种具有吸附作用的酸液缓速外加剂。采用CO2气体采集装置对外加剂延缓酸岩反应性能和缓速酸液的黏度进行了评价。结果表明,外加剂质量分数为0.5%时,缓速时间为140 min,酸液初始黏度为4.5 m Pa·s;酸岩反应过程中随着盐质量浓度和转子转速的逐渐增大,酸液缓速外加剂仍具有较好的缓速效果,并且外加剂与其他处理剂配伍性良好。     

Performance improvement of conventional and inverted polymer solar cells with hydrophobic fluoropolymer as nonvolatile processing additive

The morphology of the photoactive layer critically affects the performance of the bulk heterojunction polymer solar cells (PSCs). To control the morphology, we introduced a hydrophobic fluoropolymer polyvinylidene fluoride (PVDF) as nonvolatile additive into the P3HT:PCBM active layer. The effect of PVDF on the surface and the bulk morphology were investigated by atomic force microscope and transmission electron microscopy, respectively. Through the repulsive interactions between the hydrophilic PCBM and the hydrophobic PVDF, much more uniform phase separation with good P3HT crystallinity is formed within the active layer, resulting enhanced light harvesting and improved photovoltaic performance in conventional devices. The PCE of the conventional device can improve from 2.40% to 3.07% with PVDF additive. The PVDF distribution within the active layer was investigated by secondary ion mass spectroscopy, confirming a bottom distribution of PVDF. Therefore, inverted device structure was designed, and the PCE can improve from 2.81% to 3.45% with PVDF additive. Our findings suggest that PVDF is a promising nonvolatile processing additive for high performance polymer solar cells.     

偶联反应器格栅的制作和组装工艺

格栅支持板是换热器中的主要部件,尤其是大尺寸的格栅支持板,以前国内没有先例,如何编制好它的制作工艺和程序,并且在实际过程中得到很好的执行,遇到问题及时调整处置,对它的加工、组装、和整体安装有着特别重要的作用。     

Twin screw granulation – review of current progress

Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique.     

Microstructure and oxidation behavior of NiCr-chromium carbides coating prepared by powder-fed laser cladding on titanium aluminide substrate

In the present study, a NiCr–Cr₃C₂ powder mixture was prepared by mechanical alloying and then coated on titanium aluminide substrates by the powder-fed laser cladding process using a set of optimum parameters. The high temperature oxidation behavior of the substrate and coating was studied by isothermal annealing at 900 °C for 5 h. It was found that the microstructure of the coating is composed of γ solid solution with different chromium carbide phases (Cr₃C₂, Cr₇C₃ and Cr₂₃C₆). The presence of different chromium carbides in the microstructure of coating can be attributed to the partial melting of primary Cr₃C₂ and the formation of non-equilibrium carbide phases during rapid cooling of laser cladding. The NiCr-chromium carbide laser cladded coating samples showed superior oxidation resistance compared to the substrate. The oxidation mechanism of both coating and substrate follow the parabolic law, where the parabolic rate constant of the coating was 20% of that of the substrate at 900 °C. Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) and Grazing Angle X-Ray Diffraction (GAXRD) analysis revealed that the surface of the oxide layer formed on the NiCr-chromium carbides coating and the substrate is mostly composed of Cr₂O₃ and TiO₂, respectively.     

New observations on wear characteristics of solid Al2O3/Si3N4 ceramic tool in high speed milling of additive manufactured Ti6Al4V

Additive Manufacturing (AM) technologies applied to the titanium alloys have attracted attention from industries in recent years. Despite one of the main goals of AM is the reduction of manufacturing steps, semi-finish/finish machining operations are still required so as to obtain the desired geometrical tolerance and surface features. In this study, the solid end mill was manufactured by Al₂O₃/Si₃N₄ (Sialon) ceramic materials and employed in high-speed slot milling of Ti6Al4V alloy fabricated by the Direct Metal Laser Sintering (DMLS) AM technology to study the tool wear characteristics during processing. The Raman spectroscopic method was employed to characterize the molecular structures of Sialon ceramics for the manufacturing of the cutting tool. The morphologies and elemental maps of wear region of the ceramic tool were examined by scanning electron microscope and energy dispersive spectroscopy techniques. The results show that the adhesion wear and diffusion wear are the dominant wear mechanisms, and the chemical stability of Al₂O₃/Si₃N₄ (Sialon) ceramics fabricated as the solid ceramic tool to the attack of the atoms from additive manufactured Ti6Al4V is relatively weak under the atmosphere. The difference of thermal expansion coefficients of diffusion layer and tool substrate accelerates the initiation and propagation of thermal cracks formed on the diffusion interface. Moreover, fracturing and crater-like groves near the tool edge were finally formed due to the removal of adhered workpiece material.     

优化作业方式提高始极片质量

针对某厂铜电解种板工序存在的始极片质量波动较大的问题,从种板系统体积控制和添加剂匹配的角度出发,分析各种因素对始极片质量的影响,做出了相应的改进措施,使种板系统运行更加稳定,始极片质量得到进一步提升。     

基于双边市场理论的云制造平台定价策略

基于双边市场理论,分析了垄断的云制造平台在收取会员费和交易费模式下的最优定价策略,并利用数值仿真分析了两种收费模式下平台最优利润的差异。结果表明:两种模式下的单边最优定价均与缴费方的自网络外部性系数和免费方的交叉网络外部性系数负相关,与免费方用户数量正相关,双边最优定价受各参数影响方向取决于供需方各参数的相对大小;单边定价对象为用户数量相对较多一方,平台两边用户数量相对平衡时,单边最优定价等于双边最优定价,双边定价时的平台最优利润高于单边定价;最优定价策略由平台内交易次数决定,交易次数较多时双边收取交易费模式更优,交易次数较少时双边收取会员费更优,交易次数临界值取决于平台内网络效应和用户数量。     

Mechanical behavior of electrochemically hydrogenated electron beam melting (EBM) and wrought Ti–6Al–4V using small punch test

The influence of electrochemical charging of hydrogen at j = ?5 mA/cm² for 6, 12, 48 and 96 h on the structural and the mechanical behavior of wrought and electron beam melting (EBM) Ti–6Al–4V alloys containing 6 wt% β and similar impurities level was investigated. The length of the α/β interphase boundaries in the EBM alloy was larger by 34% compared to that in the wrought alloy. The small punch test (SPT) technique was used to characterize the mechanical behavior of the non-hydrogenated and hydrogenated specimens. It was found that the maximum load and the displacement at maximum load of the wrought alloy remained nearly stable after 6 h of charging, showing a maximum decrease of ～32% and 11%, respectively. Similarly, hydrogenation of the EBM alloy resulted in a gradual degradation in mechanical properties with charging time, up to ～81% and 86% in pop-in load and displacement at the “pop-in” load, respectively. The mode of fracture of the wrought alloy changed from ductile to semi-brittle with mud-cracking in all hydrogenated specimens. In contrast, the mode of fracture of the EBM alloy changed from a mixed mode ductile-brittle fracture to brittle fracture with star-like morphology. The degraded mechanical properties of the EBM alloy are attributed to its α/β lamellar microstructure which acted as a short-circuit path and enhanced hydrogen diffusion into the bulk as well as δ_a and δ_b hydride formation on the surface. In contrast, a surface layer with higher concentration of δ_a and δ_b hydrides in the wrought alloy served as a barrier to hydrogen uptake into the bulk and increased the alloy resistivity to hydrogen embrittlement (HE). This study shows that EBM Ti–6Al–4V alloy is more susceptible to mechanical degradation due to HE than wrought Ti–6Al–4V alloy.