脱硫石膏热处理制备注浆成型模具

石灰石-石膏湿法烟气脱硫技术以石灰石为原料吸收烟气中的二氧化硫,得到石膏晶体。在控制二氧化硫排放的同时,脱硫石膏的处理与综合利用也非常重要。以脱硫石膏为原料,分析脱硫石膏的成分,通过热处理使其脱水,并表征热处理过程对石膏物理性能的影响。将热处理后的石膏用于石膏模具的制作,并最终制备固体氧化物燃料电池阳极支撑体。燃料电池测试的结果显示,脱硫石膏可以用于管式固体氧化物燃料电池的制备。     

汽车用钢弹性模量测试探讨

采用静态拉伸试验方法对系列汽车用钢材料进行测试，得到了汽车用钢材料的弹性模量，分析了强化方式、轧制方向、塑性变形等对材料弹性模量的影响。结果表明：强化方式影响材料的弹性模量，固溶强化的汽车用钢材料弹性模量最大；材料的弹性模量表现出各向异性特点，垂直于轧制方向的弹性模量最大；塑性变形降低材料的弹性模量。研究结果为工程设计、冲压模拟、碰撞模拟、回弹模拟等提供计算依据。     

电爆喷涂粒子的约束调控机制及对沉积行为的影响

采用对喷涂粒子进行槽内约束的电爆喷涂方法,研究了喷涂粒子在垂直槽中的约束调控机制及其沉积行为。结果表明:约束深度达20mm时,即喷涂距离为丝径的100倍时,仍可获得连续、均匀的涂层。约束宽度从6mm减小至2 mm,涂层表面呈现出由粗糙的"丘壑状"形貌向均匀的"薄饼状"形貌逐渐过渡的演变趋势,且涂层厚度显著提高;能量密度从57 J/mm~3提高至152 J/mm~3,同样可提高涂层厚度并改善涂层均匀性。对喷涂粒子进行收集,发现减小约束宽度和提高能量密度均可有效细化喷涂粒子并使喷涂粒子粒径分布更加均匀。分析认为,由焦耳加热导致的"热膨胀效应"和击穿电弧伴生的"压力效应"共同决定电爆冲击波和喷涂粒子的形成,并随能量密度和约束参数的变化,对喷涂粒子表现出不同的约束调控作用,使其沉积行为产生显著差异。     

复合细化变质多元铝硅合金强化机制的研究

为改善力学性能,采用新型Al-5Ti-1B-1RE中间合金细化剂和Al-10Sr中间合金变质剂对铸态多元铝硅A356铝合金及在铸态A356铝合金中按一定比例添加Cu、Mn、Ti等元素组成的新型铝合金进行复合细化变质处理。采用光学显微镜(OM)、扫描电镜(SEM)及能谱、透射电镜(TEM)和电子式万能试验机(CSS-44100)等技术对多元铝硅合金中的第二相粒子的形态分布特征及强化机制进行分析。结果表明：经复合细化变质处理的A356铝合金中的第二相粒子共晶硅相由粗大的片层状转变为典型的纤维状,在软韧相α-Al基体晶界处较均匀的析出,α-Al相晶粒尺寸显著变小,其强化机制主要是第二相粒子共晶硅Hall-Petch晶界细晶强化；在新型铝合金中除第二相粒子共晶硅外,还存在其它较弥散分布在晶界或晶内的第二相强化粒子,多种强化机制共同起作用,当分布在晶界上时,主要是Hall-Petch强化机制；当分布在晶内时,主要是Orowan强化机制,成为阻碍位错运动的有效障碍,起到强化作用。     

Fluidization of spherical versus elongated particles: Experimental investigation using magnetic particle tracking

In biomass processing fluidized beds are used to process granular materials where particles typically possess elongated shapes. However, for simplicity, in computer simulations particles are often considered spherical, even though elongated particles experience more complex particle– particle interactions as well as different hydrodynamic forces. The exact effect of these more complex interactions in dense fluidized suspensions is still not well understood. In this study we use the magnetic particle tracking technique to compare the fluidization behavior of spherical particles to that of elongated particles. We found a considerable difference between fluidization behavior of spherical versus elongated particles in the time-averaged particle velocity field as well as in the time-averaged particle rotational velocity profile. Moreover, we studied the effect of fluid velocity and the particle's aspect ratio on the particle's preferred orientation in different parts of the bed, which provides new insight in the fluidization behavior of elongated particles.     

Coherency strain induced hardening in bulk polycrystalline ceramics: A case study with MgO-based “ceramic alloys”

The role of coherency strain at the matrix/precipitate interface toward hardening of bulk polycrystalline “ceramic alloys” has been established here. Formation of “near ideal” bulk polycrystalline ceramic microstructure characterized by the presence of uniformly distributed coherent “ultra-fine” MgCr₂O₄ particles (size: ~25 nm) within matrix (MgO) grains was achieved via solid-state precipitation during aging treatment of bulk supersaturated MgO–Cr₂O₃ solid solutions (formed during pressureless sintering in air, followed by fast cooling). The as-aged MgO–MgCr₂O₄ “ceramic alloys” exhibited hardness increment by ~73% over that of phase pure bulk MgO upon aging for just 10 hours at 1000°C in air. Evidences toward the presence of significant coherency strains across the MgO/MgCr₂O₄ coherent interfaces were obtained with transmission electron microscopy. Analysis based on hardening mechanisms and comparisons with MgO–MgFe₂O₄ system, having lesser hardening due to lower misfit strain at MgO/MgFe₂O₄ coherent interfaces (despite greater content of second-phase particles), confirm the dominant role of coherency strains toward hardness enhancement in “ceramic alloys.”     

Exergoeconomic and environmental investigation of an innovative poly-generation plant driven by a solid oxide fuel cell for production of electricity,cooling, desalinated water,and hydrogen

Fuel cell and renewable-based poly-generation plants (PGPs) are proven as advanced technologies for multiple generation purposes. To limit the greenhouse gas emissions, an innovative PGP generating electricity, cooling, desalinated water, and hydrogen is proposed in the current study. The system consists of a solid oxide fuel cell as a prime mover integrated with a gas turbine, a biomass combustion chamber, an organic Rankine cycle, an ejector refrigeration cycle, a desalination unit, and a proton exchange membrane electrolyzer integrated with solar collectors. As the most effective tools for performance evaluation, exergoeconomic, and environmental analyses have been applied. The system produces electricity of 4.4 MW, refrigeration capacity of 0.16 MW, and desalinated water of 0.96 kg/s. The attained freshwater enters the electrolyzer during 12 daylight hours, leading to hydrogen and sanitary water generation with the values of 1.55 g/s and 0.94 kg/s, respectively. The cost per unit exergy and the total cost rate of the products are 11.28 $/GJ, 223 $/h, correspondingly. Carbon dioxide emission of the system is estimated to be 10.79 kmol/MWh. According to the evaluation, the total cost rate increases with increasing current density and fuel cell inlet temperature and decreasing fuel utilization factor.     

Toward high performance solid-state lithium-ion battery with a promising PEO/PPC blend solid polymer electrolyte

A promising solid polymer blend electrolyte is prepared by blending of poly(ethylene oxide) (PEO) with different content of amorphous poly(propylene carbonate) (PPC), in which the amorphous property of PPC is utilized to enhance the amorphous/free phase of solid polymer electrolyte, so as to achieve the purpose of modifying PEO-based solid polymer electrolyte. It indicates that the blending of PEO with PPC can effectively reduce the crystallization and increase the ion conductivity and electrochemical stability window of solid polymer electrolyte. When the content of PPC reaches 50%, the ionic conductivity reaches the maximum, which is 2.04 × 10⁻⁵ S cm⁻¹ and 2.82 × 10⁻⁴ S cm⁻¹ at 25°C and 60°C, respectively. The electrochemical stability window increases from 4.25 to 4.9 V and the interfacial stability of lithium metal anode is also greatly improved. The solid-state LiFePO₄//Li battery with the PEO/50%PPC blend solid polymer electrolyte has good cycling stability, which the maximum discharge specific capacity is up to 125 mAh g⁻¹ at a charge/discharge current density of 0.5 C at 60°C.     

DPF主动再生过程颗粒排放特性试验

通过柴油发动机台架,采用后喷助燃的再生方式研究了主动再生过程中柴油机颗粒捕集器(DPF)出口的颗粒排放特性.结果表明:在主动再生期间,DPF出口颗粒浓度可增加2~3个数量级;在升温过程和再生过程,出口颗粒物数量浓度和粒径分布会因为碳载量和再生温度的共同作用而表现出差异;升温过程中,10 nm左右核模态颗粒物的排放主要由来流中颗粒物的穿透引起;再生过程中,10 nm左右核模态颗粒物的排放主要由碳烟颗粒层氧化反应生成的二次颗粒逃逸引起;整个再生期间,100 nm左右的积聚态颗粒物的排放主要由DPF载体内碳烟颗粒的逃逸引起.     

Nano-structured LSM-YSZ refined with PdO/ZrO2 oxygen electrode for intermediate temperature reversible solid oxide cells

To promote the application of traditional (La_0.8Sr_0.2)_0.95MnO_3-δ-YSZ (LSM-YSZ) oxygen electrodes to both solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) modes at intermediate temperatures, we select PdO as the catalyst and ZrO₂ as the PdO stabilizer to decorate the LSM-YSZ. The high active PdO particles enhance the electrocatalytic activity, and stable ZrO₂ can hinder the growth and agglomeration of the PdO particles. PdO and ZrO₂ are co-impregnated into the LSM-YSZ to form a nano-structured PdO/ZrO₂ -LSM-YSZ composite electrode. At 750 °C, the obtained cell attains a power density peak of 1.114 W cm⁻² in SOFC mode and shows significant improvement of the cell with LSM-YSZ composite oxygen electrode. As a SOEC, when the water content is 90 vol%AH (absolute humidity) at the hydrogen electrode, the cell exhibits an extraordinary current density of 2.322 A cm⁻² under applied voltage of 2.0 V at 750 °C. Moreover, the cell shows notable long-term stability during water electrolysis. Therefore, this study demonstrates that the nano-structured PdO/ZrO₂ -LSM-YSZ based material as a high active and stable oxygen electrode can greatly promote the application of LSM-YSZ electrode in reversible solid oxide electrolysis cell (RSOCs) field.