基于分层时延CPN的轧钢物流系统建模

用户需求的多样性和随机性会导致生产过程物流异常复杂.针对该问题,提出一种基于分层时延着色Petri网(CPN)的轧钢物流系统模型,采用自顶向下的建模方法,利用CPN对轧钢系统中功能相同的设备进行不同着色,从而降低Petri网的规模以及防止系统模型的空间爆炸问题.实验结果表明,该建模方法能真实反映复杂系统的特点,并为其优...     

Self-adaptive PID controller of microwave drying rotary device tuning on-line by genetic algorithms

The control design, based on self-adaptive PID with genetic algorithms(GA) tuning on-line was investigated, for the temperature control of industrial microwave drying rotary device with the multi-layer(IMDRDWM) and with multivariable nonlinear interaction of microwave and materials. The conventional PID control strategy incorporated with optimization GA was put forward to maintain the optimum drying temperature in order to keep the moisture content below 1%, whose adaptation ability included the cost function of optimization GA according to the output change. Simulations on five different industrial process models and practical temperature process control system for selenium-enriched slag drying intensively by using IMDRDWM were carried out systematically, indicating the reliability and effectiveness of control design. The parameters of proposed control design are all on-line implemented without iterative predictive calculations, and the closed-loop system stability is guaranteed, which makes the developed scheme simpler in its synthesis and application, providing the practical guidelines for the control implementation and the parameter design.     

1-辛基-2,3-二甲基咪唑氯盐离子液体对电解铜表面质量的影响

以1-辛基-2,3-二甲基咪唑氯盐离子液体（简写式[OMMIm]Cl）作为添加剂进行铜的电解精炼,对所得阴极铜进行扫描电镜和粗糙度测试.结果表明,在铜电解液中添加5～20 mg/L的[OMMIm]Cl作为添加剂能使阴极铜晶粒细化、板面光滑致密;对含有上述添加剂的电解液进行循环伏安和塔菲尔测试,发现该添加剂对铜离子在阴极的放电有一定的促进作用;从工艺和电化学两方面对[OMMIm]Cl在62℃的铜电解液中的稳定性进行了研究,得知该离子液体在62℃的铜电解液中保温48 h也不影响其对阴极铜细化晶粒的作用效果.     

Simple solution-combustion synthesis of Fe2TiO5 nanomaterials with enhanced lithium storage properties

The porous Fe₂TiO₅ particles are successfully synthesized through a facile one step solution combustion method. The Fe₂TiO₅ negative materials exhibit remarkable electrochemical performance with discharge capacities of 371.4?mAh g^?1 at the 100 th cycle, and display promising rate stability with discharge capacities 76.6?mAh·g^?1 at a high current density of 3.2?A?g^?1. In addition, the mechanism of electrochemistry reaction is illustrated by the CV, raman and EIS measurements, the irreversible capacity mainly causes from the irreversible lithium insertion at 1.8?V. The results indicate that the one step solution combustion synthesis of porous Fe₂TiO₅ is a promising strategy for developing low-cost and high-performance Ti-based negative materials.     

Experimental and thermodynamic investigations regarding the effect of chromium on the carbides population in cast {Ni(bal.)-0.4C-6Ta-xCr} alloys with x varying from 0 to 50 wt%

Involving a particularly strong carbide-former metallic element, the tantalum carbides are potentially very stable at elevated temperatures in term of volume fraction and morphology. The TaC phase represents a major strengthening way to allow cast chromium-rich superalloys resisting mechanical stresses at elevated temperatures. They are exploited in recent high performance cobalt-based superalloys but seemingly not in nickel-chromium refractory alloys. Earlier studies showed that the stability of TaC in Ni-Cr alloys is not so good as in the Co-Cr ones, and they evidenced that chromium carbides may compete with TaC in the formation of the carbides population. A possible way to optimize the presence of TaC in Ni-Cr alloy may consist in rating the chromium content to an ideal value but preliminary knowledge about the TaC dependence on the Cr content is compulsory. The aim of this work is precisely the investigation of the effect of the content in chromium on the appearance and stability of the TaC phase in Ni-Cr alloys, by the means of thermodynamic calculations and real experiments in parallel. A global system Ni(bal.)-xCr-0.4C-6Ta compositions (with x varying from 0 to 50 wt%) was chosen. Thermodynamic calculations were performed to know the theoretic metallurgical states inside the considered x range. These theoretic results being dependent on the suitability of the used database, real experiments of verifications were also carried out for a selection of six alloys (x = 0, 10, 20, 30, 40 and 50 wt%). The alloys prepared by respecting these compositions were cast and isothermally exposed at high temperature (1400 and 1510 K), then subjected to metallographic characterization. For the used database the calculated results showed that no TaC should never appear whatever their Cr content, while TaC were really observed in the as-cast and aged versions of the alloys containing 20 wt%Cr and more, but never alone since chromium carbides were systematically also present. When the Cr content in the alloy is too low, the TaC are rare or even no present. This allowed concluding first that the database used for the calculations needs serious improvements, followed by tests with, as first criteria of quality, a good correspondence with the present experimental results. Second, the presence of Cr in quantity high enough is surprisingly compulsory to obtain TaC carbides in quantity high enough, but it is no possible to avoid the appearance of chromium carbides. Obviously, other ways than Cr adjustments must be found to obtain TaC in nickel-based alloys as the single carbide phase and in quantity high enough to achieve high mechanical properties at high temperature.     

Facile synthesis of IrO2 nanoparticles decorated @ WO3 as mixed oxide composite for outperformed oxygen evolution reaction

Oxygen evolution reaction (OER) electrocatalysts play the critical role in efficiency and durability for different hydrogen production systems. We have successfully synthesized the earth abundant WO₃ coupled with IrO₂ as mixed oxide composite by a facile two-step chemical method. 50% reduction in noble metal contents (IW-50) followed by two times enhancement in activity, four-folds increase in bulk mass specific activity along with the stability of mixed oxide composite as compared to state –of –the art IrO₂ catalyst are affirmed. Superior performance of mixed oxide composites are perceived due to four times increase in electrochemical surface area, reduction of Tafel slope, four-fold increase of turn over frequency, electronic distortion in Ir-4f spectrum of IW-50 along with the bridging of lattice oxygen atoms between iridium and tungsten metals. We believe that it would open up the new avenues for effective utilization of noble metal with high valence tungsten metal in corrosive environment.     

The influence of multiscale fillers reinforcement into impact resistance and energy absorption properties of polyamide 6 and polypropylene nanocomposite structures

Three-phase composites (thermoplastic polymer, glass-fibres and nano-particles) were investigated as an alternative to two-phase (polymer and glass-fibres) composites. The effect of matrix and reinforcement material on the energy absorption capabilities of composite structures was studied in details in this paper. Dynamic and quasi-static axial collapse of conical structures was conducted using a high energy drop tower, as well as Instron universal testing machine. The impact event was recorded using a high-speed camera and the fracture surface was investigated with scanning electron microscopy (SEM). Attention was directed towards the relation between micro and macro fracture process with crack propagation mechanism and energy absorbed by the structure. The obtained results indicated an important influence of filler and matrix material on the energy absorption capabilities of the polymer composites. A significant increase in specific energy absorption (SEA) was observed in polyamide 6 (PA6) reinforced with nano-silica particles and glass-spheres, whereas addition of montmorillonite (MMT) caused a decrease in that property. On the other hand, very little influence of the secondary reinforcement on the energy absorption capabilities of polypropylene (PP) composites was found.     

Controllable electrodeposition synthesis of Pd/TMxOy-rGO/CFP composite electrode for highly efficient methanol electro-oxidation

A novel and high-efficiency Pd/TM_xO_y-rGO/CFP (TM_xO_y = Co₃O₄, Mn₃O₄, Ni(OH)₂) electrocatalyst for directly integrated membrane electrode was synthesized by controllable cyclic voltammetry electrodeposition combined with hydrothermal process. The results showed excellent performance towards methanol oxidation reduction. The Pd/Co₃O₄-rGO/CFP as-prepared catalyst has the best electrocatalytic activity, and mass activity is 5181 mA·mg⁻¹_Pd, which is about 40 times and 4.3 times that of the commercial Pd/C and Pt/C catalyst (JM). It can be attributed that the small size of Pd nanoparticle, uniformity of distribution, and the synergistic interaction between transition metal oxide on the support surface and Pd nanoparticles. The prepared Pd/TM_xO_y-rGO/CFP composite electrode is a promising catalyst for integrated membrane electrode assembly of proton exchange membrane fuel cells in the future.     

Electrodeposited Pt nanorods on a novel flowered-like nanostructured NiCo alloy as an electrocatalyst for methanol oxidation

For the first time, a novel system of Pt nanorods supported on nano flowered-like structure NiCo alloy has been successfully electro-synthesized onto a glassy carbon electrode for the electrocatalytic oxidation of methanol. The electrodeposited system has been characterized using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The electrocatalytic efficiency of the electro-fabricated system of Pt/NiCo/GCE have been confirmed by cyclic voltammetric (CV) and current-time methods. It is discovered that the electrodeposited nano flowered NiCo alloy substrate has a great effect on the electrocatalytic properties of the electrodeposited Pt nanorods. The electrocatalytic efficiency of the new system for methanol oxidation reaction (MOR) is found to be 174 A/g_Pt. The effect of electrodeposition time for NiCo alloy has been studied. Also, the effect of pH, temperature, and concentration for the electrodeposition of Pt catalyst on the electrocatalytic properties of the Pt/NiCo/GCE have been studied for detection the optimum conditions. The mechanism of the electrocatalytic oxidation of methanol has been discussed. Furthermore, the stability and the corrosion resistance test of the Pt/NiCo/GCE system have been investigated by electrochemical impedance spectroscopy (EIS), Tafel plot and current-time methods.     

Application of a deep eutectic solvent to prepare nanocrystalline Ni and Ni/TiO2 coatings as electrocatalysts for the hydrogen evolution reaction

The paper reports the electrochemical deposition of nanocrystalline nickel and composite nickel-titania films as effective electrocatalysts for the hydrogen evolution reaction. To produce the composite Ni/TiO₂ electrodeposits, a plating bath based on a deep eutectic solvent, a novel kind of ionic liquids, was used for the first time. The electrolyte contained ethaline (a eutectic mixture of choline chloride and ethylene glycol), 1 M NiCl₂⋅6H₂O and the addition of extra water (3, 6, 9 mol dm⁻³). Titania dispersed phase was introduced into the electrolyte as nanopowder Degussa P 25 (0–10 g dm⁻³). It was shown that the introduction of extra water to the plating bath allowed appreciably increasing the content of TiO₂ phase in the coating (from ca. 2 to 10 wt%). The effects of electrolysis conditions on the TiO₂ content in the coatings, surface morphology and microstructure were determined. The results of voltammetry measurements showed that the Ni and composite Ni/TiO₂ coatings electrodeposited from the plating electrolyte based on a deep eutectic solvent exhibit improved electrocatalytic properties towards the hydrogen evolution reaction as compared with deposits obtained from commonly used aqueous electrolytes. The mechanism of the hydrogen evolution reaction on the Ni and composite Ni/TiO₂ coatings is a combination of Volmer-Heyrovsky reactions. The introduction of TiO₂ particles into the nickel matrix results in the acceleration of the hydrogen evolution reaction. An improved catalytic activity of Ni/TiO₂ composites towards the hydrogen evolution reaction can be associated with the presence of titanium-containing redox couples on the surface.