Plasma-assisted CO2 reforming of methane over Ni-based catalysts: Promoting role of Ag and Sn secondary metals

Carbon dioxide (CO₂) and methane (CH₄) are the primary greenhouse gases (GHGs) that drive global climate change. CO₂ reforming of CH₄ or dry reforming of CH₄ (DRM) is used for the simultaneous conversion of CO₂ and CH₄ into syngas and higher hydrocarbons. In this study, DRM was investigated using Ag–Ni/Al₂O₃ packing and Sn–Ni/Al₂O₃ packing in a parallel plate dielectric barrier discharge (DBD) reactor. The performance of the DBD reactor was significantly enhanced when applying Ag–Ni/Al₂O₃ and Sn–Ni/Al₂O₃ due to the relatively high electrical conductivity of Ag and Sn as well as their anti-coke performances. Using Ag–Ni/Al₂O₃ consisting of 1.5 wt% Ag and 5 wt% Ni/Al₂O₃ as the catalyst in the DBD reactor, 19% CH₄ conversion, 21% CO₂ conversion, 60% H₂ selectivity, 81% CO selectivity, energy efficiency of 7.9% and 0.74% (by mole) coke formation were achieved. In addition, using Sn–Ni/Al₂O₃, consisting of 0.5 wt% Sn and 5 wt% Ni/Al₂O₃, 15% CH₄ conversion, 19% CO₂ conversion, 64% H₂ selectivity, 70% CO selectivity, energy efficiency of 6.0%, and 2.1% (by mole) coke formation were achieved. Sn enhanced the reactant conversions and energy efficiency, and resulted in a reduction in coke formation; these results are comparable to that achieved when using the noble metal Ag. The decrease in the formation of coke could be correlated to the increase in the CO selectivity of the catalyst. Good dispersion of the secondary metals on Ni was found to be an important factor for the observed increases in the catalyst surface area and catalytic activities. Furthermore, the stability of the catalytic reactions was investigated for 1800 min over the 0.5 wt% Ag-5 wt% Ni/Al₂O₃ and 0.5 wt% Sn-5 wt% Ni/Al₂O₃ catalysts. The results showed an increase in the reactant conversions with an increase in the reaction time.     

κ-Opioid Signaling in the Lateral Hypothalamic Area Modulates Nicotine-Induced Negative Energy Balance

Several studies have reported that nicotine, the main bioactive component of tobacco, exerts a marked negative energy balance. Apart from its anorectic action, nicotine also modulates energy expenditure, by regulating brown adipose tissue (BAT) thermogenesis and white adipose tissue (WAT) browning. These effects are mainly controlled at the central level by modulation of hypothalamic neuropeptide systems and energy sensors, such as AMP-activated protein kinase (AMPK). In this study, we aimed to investigate the kappa opioid receptor (κOR)/dynorphin signaling in the modulation of nicotine’s effects on energy balance. We found that body weight loss after nicotine treatment is associated with a down-regulation of the κOR endogenous ligand dynorphin precursor and with a marked reduction in κOR signaling and the p70 S6 kinase/ribosomal protein S6 (S6K/rpS6) pathway in the lateral hypothalamic area (LHA). The inhibition of these pathways by nicotine was completely blunted in κOR deficient mice, after central pharmacological blockade of κOR, and in rodents where κOR was genetically knocked down specifically in the LHA. Moreover, κOR-mediated nicotine effects on body weight do not depend on orexin. These data unravel a new central regulatory pathway modulating nicotine’s effects on energy balance.     

Multi-discharge EDM coring of single crystal SiC ingot by electrostatic induction feeding method

A new technique of EDM coring of single crystal silicon carbide (SiC) ingot was proposed in this paper. Currently single crystal SiC devices are still of high cost due to the high cost of bulk crystal SiC material and the difficulty in the fabrication process of SiC. In the manufacturing process of SiC ingot/wafer, localized cracks or defects occasionally occur due to thermal or mechanical causes resulted from fabrication processes which may waste the whole piece of material. To save the part of ingot without defects and maximize the material utilization, the authors proposed EDM coring method to cut out a no defect ingot from a larger diameter ingot which has localized defects. A special experimental setup was developed for EDM coring of SiC ingot in this study and its feasibility and machining performance were investigated. Meanwhile, in order to improve the machining rate, a novel multi-discharge EDM coring method by electrostatic induction feeding was established, which can realize multiple discharges in single pulse duration. Experimental results make it clear that EDM coring of SiC ingot can be carried out stably using the developed experimental setup. Taking advantage of the newly developed multi-discharge EDM method, both the machining speed and surface integrity can be improved.     

东兴铝业嘉峪关分公司铝灰渣循环利用研究

铝灰渣是铝熔铸过程中产生的废弃物。本文主要介绍了酒钢东兴铝业嘉峪关分公司铝灰渣的产生量、排放、利用情况、化学成分及表面特征,并简要介绍了铝灰渣、铝灰的循环利用途径。     

Enhance cycling performance of LiMn2O4 cathode by Sr2+ and Cr3+ doping

Spinel LiSr_0·1Cr_0·1Mn_1·8O₄ was synthesised by high temperature solid state method in order to enhance the electrochemical performance. The LiSr_0·1Cr_0·1Mn_1·8O₄ (LSCMO) materials were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical tests. The XRD and SEM studies confirm that LSCMO had spinel crystal structure with a space group of Fd3m, and the particle of LSCMO shows irregular shape. The cyclic voltammetry data illustrated that the heavy current charge–discharge performance of LMO was improved by Sr²⁺ and Cr³⁺ doping. The galvanostatic charge–discharge of LSCMO cathode materials was measured at 1, 5, 10 and 20 C. The results indicated that LSCMO improved the capacity retention.     

仪器仪表产品脉冲耐压试验要求和保护器件的选择

仪器仪表产品的脉冲耐压试验是产品型式试验、例行试验中的基本内容。通过对GB4793.1标准的整理,归纳了仪器仪表产品的脉冲耐压试验要求。通过对试验方法和设备特性的梳理,总结了特性参数,并介绍了应对脉冲耐压试验可采取的保护器件的类别及选用方法。     

Polarity Effect and Electromagnetic Radiation of Partial Discharge Accompanying Growth of Electrical Tree

We have investigated the characteristics of radiated electromagnetic (EM) waves from positive and negative partial discharges (PD) in epoxy resin and cross‐linked polyethylene. We found that there is a correlation among the EM level from PD, the positive PD current, and electrical trees. Therefore, the growth of an electrical tree produces a lot of positive PD. We have also investigated the characteristics of the frequency region of EM waves from PD in air, insulating oil, and liquid epoxy in addition to the above insulators. EM waves were detected in the frequency region of 40 MHz to 300 MHz from positive and negative PD in epoxy resin and cross‐linked polyethylene. EM waves were also detected in the frequency region of 40 MHz to 150 MHz from positive and negative PD in air. In the case of insulating oil and liquid epoxy, EM waves were detected in the frequency regions of 40 MHz to 150 MHz from positive PD, and 40 MHz to 250 MHz from negative PD. The frequency region differed depending on the material and the discharge polarity. Our investigation indicates that the cause is differences in electric field strength at the time of PD occurrence.     

Effect of Moving Speed of Charged Metallic Spherical Electrode on Electrostatic Discharge

In this investigation, the nature of the electrostatic discharge (ESD) that occurs when a charged object moves toward a stationary grounded object is experimentally clarified. The spark lengths, discharge currents, and induced voltages in a magnetic probe were measured when a charged metallic spherical electrode connected to a 422 pF capacitor approached a stationary grounded object, which was the current target, for different moving speeds of the charged metallic spherical electrode in a range of 1 mm/s to 100 mm/s. The charge voltages of the capacitor were +6.5 kV and +10 kV. Based on the results, the average gap length shortened with the speed of the spherical electrode. The average peak values of the discharge current and the induced voltage were likely to increase with the speed of the spherical electrode. The average rise times of the discharge current and the induced voltage were likely to drop with the speed of the spherical electrode. The relation between the spark length and the discharge current due to the ESD can be explained qualitatively by using an equation derived from the spark resistance formula proposed by Rompe and Weizel.     

采油污水处理工艺探讨

针对采油污水的水质特点,以及其中有机污染物的组成,结合现有处理工艺,确定了以生化法降解有机污染物为核心的处理工艺,实现了达标排放,并对处理工艺适用性进行了分析。     

大位移井钻柱振动规律研究与应用

在大位移井钻井工程中钻柱受着各种振动，当各种振动共振时，钻柱承受着非常大的动载，很容易受损，同时，钻柱的振动影响着井壁的稳定，严重威胁着井下的作业安全。以大位移井近井底的钻柱为研究对象，分析了钻柱振动行为所遵循的规律。采用线性分析法，获得了大位移井钻柱横向振动和扭转振动的频谱方程。同时获得了钻柱各种共振频率的分布。经分析表明：大位移井钻柱的横向振动和扭转振动的共振频率与实际钻井转速非常接近，应合理选择转速以减小钻柱共振的发生。文章的分析研究为大位移井钻柱动态行为的研究提供了理论依据。