Thermal properties of hierarchical YSZ and LZO ceramic microspheres with multi-scaled voids investigated by using theoretical,experimental and simulation methods

Heat transfer within ceramic feedstock powders is still unclear, which impedes optimization of the thermal and mechanical properties of the thermal sprayed coatings. The microspheres (yttria-stabilized zirconia YSZ and lanthanum zirconate LZO) were prepared via the electro-spraying assisted phase inversion method (ESP). The thermal properties of the two ESP microspheres and a commercial hollow spherical powder (HOSP) were investigated by using theoretical, experimental, and simulation methods. Thermal conductivity of the single microsphere was estimated via a novel nest model that was derived from the Maxwell-Eucken 1 and the EMT model. Thermal conductivity of a single YSZ/LZO-ESP microsphere prepared at 1100–1200 °C was within 0.36–0.75 W/m K, which was ～ 20 % lower than that of a single YSZ-HOSP microsphere with a similar porosity. Heat flux simulation showed that high tortuosity around the multi-scaled voids of the ESP microsphere led to a more efficient decrease in thermal conductivity compared with total porosity.     

两种混合单元混合机理的数值模拟

为了研究SV型和SX型混合单元在全静态乳化器的混合机理,使用群体平衡模型对乳化器内部流场进行模拟分析。结果表明,SV型与SX型混合单元的混合机理是油相与水相材料通过混合单元时其空间流动方向改变,在流场内形成大量的漩涡,从而达到乳化的目的;通过比较流体在经过SV型和SX型混合单元后的水相索特平均直径(d_(32)),得出SV型混合单元的乳化效果更强,但同时消耗更多的能量,压降更大。     

Locating wind farm for power and hydrogen production based on Geographic information system and multi-criteria decision making method: An application

Hydrogen generation from renewable energy resources is considered as a suitable solution to solve the problems related to the energy sector and the reduction of greenhouse gases. The aim of this study is to provide an integrated framework for identifying suitable areas for the construction of wind farms to produce hydrogen. For this purpose, a combined method of Geographic Information System (GIS) and multi-criteria decision making (MCDM) has been used to locate the power plant in Yazd province. The GIS method in the present study consisted of two parts: constraints and criteria. The constraint section included areas that were unsuitable for the construction of wind farms to produce power and hydrogen. In the present study, various aspects such as physical, economic and environmental had been considered as constraints. In the criteria section, eight different criteria from technical aspects (including average wind speed, hydrogen production potential, land slope) and economic aspects (including distance to electricity grid, distance to urban areas, distance to road, distance to railway and distance to centers of High hydrogen consumption) had been investigated. The MCDM tool had been used to weigh the criteria and identify suitable areas. Analytic Hierarchy Process (AHP) technique was used for weighting the criteria. The results of AHP weighting method showed that economic criteria had the highest importance with a value of 0.681. The most significant sub-criterion was the distance to urban areas and the least significant sub-criterion was the distance to power transmission lines. The results of GIS-MCDM analysis had shown that the most proper areas were in the southern and central sectors of Yazd province. In addition, the feasibility of hydrogen production from wind energy had shown that this province had the capacity to generate hydrogen at the rate of 53.6–128.6 tons per year.     

Novel proton-conducting layered perovskite based on BaLaInO4 with two different cations in B-sublattice: Synthesis,hydration, ionic (O2−, H+) conductivity

The present study focused on the novel material with significantly improved properties for the application in the area of clean energy. The new complex oxide BaLaIn_0·5Y_0·5O₄ with layered perovskite structure was obtained for the first time. It was proved that the introduction of Y³⁺ ions in the perovskite layer of BaLaInO₄ leads i) to the rise of the oxygen-ionic conductivity due to the increase in mobility of oxygen ions as a result of the expand of the cell volume and ii) to the enhancement of protonic conductivity due to the increase in the proton concentration and mobility. The sample BaLaIn_0·5Y_0·5O₄ is nearly pure proton conductor below 400 °C and has the protonic conductivity value 1.6?10^?5 S/cm at this temperature.     

High voltage and self-healing zwitterionic double-network hydrogels as electrolyte for zinc-ion hybrid supercapacitor/battery

The hydrogel electrolyte is an important part of safety and development potential in zinc-based energy storage equipment due to its inherent low mechanical strength and voltage decomposition. However, hydrogel electrolytes possess a reduced working life for zinc dendrites growth and a narrow voltage window. In this study, a hydrogel electrolyte prepares by the zwitterionic monomer [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) (MS) and sodium alginate (SA) alleviate these problems. The zwitterionic double-network hydrogel has good mechanical strength, inhibits the growth of zinc dendrites, enhances practicability, greatly increases the voltage window (0–2.4 V), and has self-healing properties to its rich functional groups. The assembled zinc-ion hybrid supercapacitors (ZHSs) have a high-power density of 172.33 W kg^?1 and an energy density of 88.56 Wh·kg^?1 at 0.5 A g^?1. The assembled zinc-ion battery also has good electrochemical performance. Flexible ZHSs and batteries provide power to the timer stably under different bending angles. The zwitterionic double-network hydrogel can be applied to both zinc-based supercapacitors and batteries.     

Optimization and efficiency analysis of methanol SOFC-PEMFC hybrid system

In order to improve the power generation efficiency of fuel cell systems employing liquid fuels, a hybrid system consisting of solid oxide fuel cell (SOFC) and proton exchange membrane fuel cell (PEMFC) is proposed. Utilize the high temperature heat generated by SOFC to reform as much methanol as possible to improve the overall energy efficiency of the system. When SOFC has a stable output of 100 kW, the amount of hydrogen after reforming is changed by changing the methanol flow rate. Three hybrid systems are proposed to compare and select the best system process suitable for different situations. The results show that the combined combustion system has the highest power generation, which can reach 350 kW and the total electrical efficiency is 57%. When the power of the tail gas preheating system is 160 kW, the electrical efficiency can reach 75%. The PEM water preheating system has the most balanced performance, with the electric power of 300 kW and the efficiency of 66%.     

Adjusting electronic structure coupling of Fe–Ni2P (NiFeP-MOF) multilevel structure for ultra-activity and durable catalytic water oxidation

Efficient electrocatalyst for alkaline oxygen evolution reaction is the critical core to the wide application of metal-air energy storage and water electrolysis hydrogen energy. Therefore, appropriate design of highly active and stable non-noble metal oxygen evolution electrocatalyst with good electronic structure and multilevel structure is both a goal and a challenge. Here, we report a Fe–Ni₂P electrocatalyst (NiFeP-MOF) with multilevel structure, which was obtained by anion exchange on the basis of Fe–Ni(OH)₂ (NiFe-MOF) grown on nickel foam in situ by solvothermal method. As expected, Fe substitution regulates the Ni oxidation state in the NiFeP-MOF and realizes electronic structure coupling, showing a highly active and stable oxygen evolution reaction (OER) in alkaline electrolyte solution. Specifically, the NiFeP-MOF demonstrates an ultralow overpotentials (232 mV, 10 mA cm^?2; 267 mV 100 mA cm^?2), respectively, an extremely small Tafel slope (34 mV dec^?1). Separately, the electrocatalyst shows an excellent cycle stability at 10 mA cm^?2 for 12 h (43,200 s). More importantly, this work come up with an available policy for the preparation of excellent alkaline hydrolysis electrolysis catalysts and air cathodes with excellent performance.     

“三软”煤层沿空掘巷围岩力学环境及支护体承载性能分析

为应对"三软"煤层综放沿空掘巷围岩稳定性差的问题,通过数值模拟分析、揭示"三软"煤层中锚杆、锚索载荷变化规律及其与围岩变形相互作用关系,为"三软"煤层沿空掘巷锚网支护参数优化提供理论依据,改善了巷道支护状况,降低相邻工作面间保护煤柱压煤率,提高矿井经济效益和社会效益。     

超高分子量聚乙烯纤维增强中空蜂窝模压复合材料性能研究

为研制车船等壳体所用的轻质、高强复合板材,选用超高分子量聚乙烯(UHMWPE)短纤维纱,制备成单层经纬为120根/(10 cm)的平纹组织,采用多组经纱持续更替交织层的方法制成2L(1+0)型、4L(2+1)型、6L(3+2)型3种多层角联锁结构织物,采用扦插芯棒、模压成型方法制成菱形蜂窝状的热固性环氧树脂基中空板,并与2块真空吸液法制成的面板组成“三合一”复合板,同时测定了复合板材的结构特征及其平拉、平压和弯曲性能。结果表明:3种类型复合板的密度均远小于水的密度,其中6L(3+2)型最小,为0.48 g/cm³;复合板层数越多,环氧树脂越难渗透尤其是在中空板菱形交叉点处,复合板平拉、平压、抗弯曲强度则呈现递增,制成的6L(3+2)型复合板试样平压强度可达到1.03 MPa。     

Cloning,sequencing and structural analysis of membrane-bound polyphenol oxidase from Granny Smith apples (Malus × domestica Borkh)

The gene sequence coding for the membrane-bound polyphenol oxidase (mPPO) with a length of 1761 bp was cloned by PCR method and shown to contain one highly conserved sequence encoding a di-copper-binding region. The predicted three-dimensional structure of mPPO indicated that the active site was located near two copper ions and composed of a typical bundle of four α-helices. Each of the two catalytic copper ions was coordinated with three histidine residues in the hydrophobic pocket, yielding His 180, His 201, His 210, His 332, His 336 and His 366. Docking studies showed that 4-methylcatechol and chlorogenic acid have different binding models due to different ligand sizes and binding sites in the active centre, and it was found that the smaller compound exhibited a higher affinity for mPPO. Molecular dynamic simulation results indicated that Phe 353 is important in controlling enzymatic activity through influencing substrate coordination in the active site.