金属Ce氢化-氮化反应动力学

以金属Ce为原料，对Ce氢化-氮化动力学参数进行研究，分别考察了初始反应温度、原料气体初始压力和Ce片厚度等对金属Ce氢化-氮化反应的影响。研究结果表明：升高初始反应温度有利于缩短氢化过程的诱导时间，但对氢化反应速率无明显影响；提高H₂初始压力和降低片层厚度能明显加快氢化反应速率。此外，通过X射线衍射（XRD）和扫描电镜（SEM）等表征证明氢化铈可以与N₂反应得到氮化铈（CeN）和H₂，但反应需要较高的温度以克服活化能，增加初始反应温度和N₂初始压力可以提高反应速率。综合考虑，初始反应温度为350 ℃、N₂初始压力为60 kPa是氢化铈氮化的较优条件。     

Fabrication of TiO2 photocatalytic electrode and contamination control with atmospheric pressure O2 plasma jet

In this study, we demonstrate the fabrication of TiO₂ photocatalytic electrode by sol-gel and electrospinning technique. The anatase TiO₂ nanofiber is successfully formed after thermal annealing at 260°C. As-prepared TiO₂ photocatalytic electrode contains surface contamination, which includes a polymer binder such as ethyl cellulose, carbon by carbonization of polyvinylpyrrolidone, and residue polyvinylpyrrolidone. To efficiently remove the surface contaminants from the TiO₂ photocatalytic electrode, we employ an atmospheric-pressure O₂ plasma jet and the exposure time is controlled by the scanning rate. As the results, photodegradation efficiency of methylene blue is significantly enhanced with a scanning rate in the range of 100-500 μm/s and was saturated with a scanning rate in the range of 10-100 μm/s.     

Role of Zinc (Zn) in Human Reproduction: A Journey from Initial Spermatogenesis to Childbirth

Zinc (Zn), the second-most necessary trace element, is abundant in the human body. The human body lacks the capacity to store Zn; hence, the dietary intake of Zn is essential for various functions and metabolism. The uptake of Zn during its transport through the body is important for proper development of the three major accessory sex glands: the testis, epididymis, and prostate. It plays key roles in the initial stages of germ cell development and spermatogenesis, sperm cell development and maturation, ejaculation, liquefaction, the binding of spermatozoa and prostasomes, capacitation, and fertilization. The prostate releases more Zn into the seminal plasma during ejaculation, and it plays a significant role in sperm release and motility. During the maternal, labor, perinatal, and neonatal periods, the part of Zn is vital. The average dietary intake of Zn is in the range of 8–12 mg/day in developing countries during the maternal period. Globally, the dietary intake of Zn varies for pregnant and lactating mothers, but the average Zn intake is in the range of 9.6–11.2 mg/day. The absence of Zn and the consequences of this have been discussed using critical evidence. The events and functions of Zn related to successful fertilization have been summarized in detail. Briefly, our current review emphasizes the role of Zn at each stage of human reproduction, from the spermatogenesis process to childbirth. The role of Zn and its supplementation in in vitro fertilization (IVF) opens opportunities for future studies on reproductive biology.     

Ablation behavior and mechanism of bulk MoAlB ceramic at ∼1670–2550 °C in air plasma flame

In this work, MoAlB samples for plasma exposure test were condensed by spark plasma sintering at 1200 °C for 10 min. Ablation resistance of MoAlB ceramic was investigated in a plasma torch facility for about 30 s at high temperature range of ～1670?2550 °C, which provided a quasi-real hypersonic service environment. The results showed that the linear ablation rate was increased from 0 μm/s at ～1670 °C to 86.4 μm/s at ～2550 °C. At ～1670 °C, the ablated surface of MoAlB ceramic was covered by Al₂O₃ layer, presenting excellent ablation resistance. At ～2220 °C, the macroscopic cracks were induced by thermal stress, which opened up channels for the inward diffusion of oxygen and deteriorated the ablation resistance of the substrate. Above ～2400 °C, the volatile MoO₃ and B₂O₃ and the erosion of viscous oxides by the high shearing force of plasma stream were the main ablation mechanisms.     

Recent developments in catalyst synthesis using DBD plasma for reforming applications

The catalyst has a significant role in gas processing applications such as reforming technologies for H₂ and syngas production. The stable catalyst is requisite for any industrial catalysis application to make it commercially viable. Several methods are employed to synthesize the catalysts. However, there is still a challenge to achieve a controlled morphology and pure catalyst which majorly influences the catalytic activity in reforming applications. The conventional methods are expansive, and the removal of the impurities are major challenges. Nevertheless, it is not straightforward to achieve the desired structure and stability. Therefore, significant interest has been developed on the advanced techniques to take control of the physicochemical properties of the catalyst through non-thermal plasma (NTP) techniques. In this review, the systematic evolution of the catalyst synthesis using NTP technique is elucidated. The emerging DBD plasma to synthesized and effective surface treatment is reviewed. DBD plasma synthesized catalyst performance in reforming application for H₂ and syngas production is summarised. Furthermore, the status of DBD plasma for catalyst synthesis and proposed future avenues to design environmentally suitable and cost-effective synthesis techniques are discussed.     

Experimental investigation on the cracking of pre-combustion cracking gas with gliding arc discharge plasma

To improve the quality of pre-combustion cracking gas, the gliding arc discharge plasma is adopted in this paper. The influence of incoming flow rate, electrode gap distance and discharge frequency on cracking effect have been experimentally studied. The results show that through plasma cracking, the concentration of H₂ increases while the concentration of CH₄ and C₂H₄ decrease. With different fuel ratio conditions, the variation trend of C/H ratio as well as the mass flow of carbon and hydrogen atoms in the cracking products vary from each other. The cracking effect becomes weaker with the increase of incoming flow rate, while is better when the fuel ratio is larger. Given the flow rate of 18slpm and 24slpm, the best cracking effect can be acquired with the electrode gap of 1.5 mm. Besides, the effect of gliding arc discharge plasma cracking is weakened as the discharge frequency rises.     

The structure of an electronegative magnetized plasma sheath with non-extensive electron distribution

In this paper, an electronegative magnetized plasma sheath model with non-extensive electron distribution is established, and the Bohm criterion affected by the non-extensive parameter q is theoretically derived. The ion Mach number varies with q. The numerical simulation results show that compared with electronegative magnetized plasma sheath with Maxwell distribution (q = 1), the sheath structures with super-extensive distribution (q < 1) and sub-extensive distribution (q > 1) are different. The physical quantities including the sheath potential distribution, ion density distribution, the electron density distribution, negative ion density distribution and the net space charge density distribution are discussed. It is shown that the non-extensive parameter q has a significant influence on the structure of the electronegative magnetized plasma sheath. Due to the Lorentz force, both the magnitude and the angle of the magnetic field affect the structure of the sheath, whether the electrons are Maxwell distributed or non-extensively distributed.     

Application of dielectric barrier discharge (DBD) plasma packed with glass and ceramic pellets for SO2 removal at ambient temperature: optimization and modeling using response surface methodology

Air pollution is a major health problem in developing countries and has adverse effects on human health and the environment. Non-thermal plasma is an effective air pollution treatment technology. In this research, the performance of a dielectric barrier discharge (DBD) plasma reactor packed with glass and ceramic pellets was evaluated in the removal of SO₂ as a major air pollutant from air in ambient temperature. The response surface methodology was used to evaluate the effect of three key parameters (concentration of gas, gas flow rate, and voltage) as well as their simultaneous effects and interactions on the SO₂ removal process. Reduced cubic models were derived to predict the SO₂ removal efficiency (RE) and energy yield (EY). Analysis of variance results showed that the packed-bed reactors (PBRs) studied were more energy efficient and had a high SO₂ RE which was at least four times more than that of the non-packed reactor. Moreover, the results showed that the performance of ceramic pellets was better than that of glass pellets in PBRs. This may be due to the porous surface of ceramic pellets which allows the formation of microdischarges in the fine cavities of a porous surface when placed in a plasma discharge zone. The maximum SO₂ RE and EY were obtained at 94% and 0.81 g kWh⁻¹, respectively under the optimal conditions of a concentration of gas of 750 ppm, a gas flow rate of 2 l min⁻¹, and a voltage of 18 kV, which were achieved by the DBD plasma packed with ceramic pellets. Finally, the results of the model's predictions and the experiments showed good agreement.