当代中国大中专院校电工技术教学的两大发明

以4项发明专利,对照电工和电力电子技木教科书上基础电路教材,论述龚氏桥全整流电路和龚氏斩控交流调压电路必将轻松走进世界科学讲堂和教科书,为电工和电力电子技术的教科书上独占一大类的相控整流电路——龚氏桥全整流电路和一个龚氏斩控式交流调压电路。它们是大中专院校电工和电力电子技术教学的四大发明中最重要的两大发明。     

多级提水高扬程泵站高压变频节能的计算与分析

针时平定县供水管理局娘子关各站机电水泵在直接启动时站与站之间存在流量不匹配问题而造成扬程损失,提出了改进措施,重点对多级提水高扬程泵站的高压变频节能进行了计算与分析.     

高熵氧化物的设计及其在锂离子电池中的应用研究进展

储能技术的革命性变化对下一代锂离子电池(LIBs)负极材料提出了更高的要求。近年来,一类具有复杂化学计量比的新型材料——高熵氧化物(HEOs)逐渐进入人们的视野并走向繁荣。理想的元素可调节性和吸引人的协同效应使 HEOs有望突破传统阳极的综合性能瓶颈,为电化学储能材料的设计和发展提供新的动力。本文分别从化学成分调控和结构设计2个方面结合本课题组近年来的研究及国内外重要文献,综述了HEOs作为LIBs负极材料的研究进展。在化学成分调控方面通过金属杂原子掺杂、非金属杂原子掺杂来提高HEOs的本征活性。在结构设计方面,通过构建一维结构、二维结构、三维结构、空心结构以及复合碳材料来增加HEOs的反应活性位点数量,从而提高储锂性能。最后,对HEOs在LIBs领域的发展进行了展望。     

Ir和IrPd催化剂的合成及结构调控对其甲醇氧化性能的影响

以三嵌段共聚物P123(聚环氧乙烷-聚环氧丙烷-聚环氧乙烷,PEO₂₀-PPO₇₀-PEO₂₀)为还原剂和保护剂,比较了水热法和溶剂热法对纯Ir和IrPd合金催化剂合成及其电催化氧化甲醇(MOR)性能的影响。对于纯Ir催化剂,在相同条件下,溶剂热法能更好地促进Ir前驱体的还原。对于IrPd合金催化剂,溶剂热法可制得表面富含Ir但MOR活性较低的核壳结构产物(IrPd-S)。水热反应得到的不同原子比(IrPd、Ir₂Pd、IrPd₂)的产物粒径更小,元素分布更均匀。其中比例为1∶1的IrPd (IrPd-H)催化剂的MOR电催化活性最高。上述结果表明,通过调节溶剂类型以及P123的结构诱导作用,可以有效地调节纯Ir和IrPd合金催化剂的结构、表面组成和电催化活性。     

Magnetic and dielectric response of M-type barium hexaferrite

Barium hexaferrite (BaFe₁₂O₁₉) is a promising candidate for ceramics, microwave devices and numerous applications. Barium hexaferrite was synthesised via the sol-gel auto-combustion technique using glycine fuel. The X-ray diffraction technique confirmed the hexagonal structure of the particles with space group P63/mmc. The morphological analysis was performed using the field-emission scanning microscope, and the images displayed the plate-like particle formation. Transmission electron microscopy was employed to determine the average particle size of the sample, which was estimated to be 155.93 nm. The magnetic studies were taken through the vibrating sample magnetometer (VSM) at 300 K, with which the saturation magnetization (M_s), coercivity (H_c), squareness ratio (M_r/M_s), and energy product (BH_max) was calculated, and the particles were validated to be in single domain arrangement. The dielectric properties were investigated through the LCR meter. Koop and Maxwell-Wagner's model was used to interpret charge conduction and the occurrence of relaxations in the system.     

一体化电极电催化二氧化碳还原研究进展

电催化二氧化碳还原反应(E-CO₂RR)可在温和条件下将CO₂转化成高附加值燃料或化学品,近年来受到广泛关注,其在实际反应中涉及到气体扩散和多电子转移等复杂过程,构筑高效、稳定的催化电极是其发展的核心之一。然而,传统涂敷电极制备时,需要将催化剂与粘结剂混合涂覆于集流体表面,此过程会造成活性位点包埋和传质过程受限,致使催化剂活性位利用率下降,同时在反应过程中电极表面容易粉化,造成稳定性下降,难以重复利用。因此,如何调控电极反应界面,提升催化剂活性位的利用率仍面临挑战。将催化剂原位生长于集流体上得到的一体化电极可直接应用于电催化反应,不仅有利于提升活性位利用率以及电荷传输能力,还能有效调控三相界面处的微观反应环境(如pH、反应物及反应中间体的浓度等),从而实现电催化性能强化。本文综述了一体化电极用于E-CO₂RR的最新进展,分析了结构和表界面调控对E-CO₂RR性能的影响规律,并对该领域仍然存在的挑战和未来一体化E-CO₂RR电极的发展进行了评述与展望。     

Current Advances in Aptamer-based Biomolecular Recognition and Biological Process Regulation

The interaction between biomolecules with their target ligands plays a great role in regulating biological functions. Aptamers are short oligonucleotide sequences that can specifically recognize target biomolecules via structural complementarity and thus regulate related biological functions. In the past ten years, aptamers have made great progress in target biomolecule recognition, becoming a powerful tool to regulate biological functions. At present, there are many reviews on aptamers applied in biomolecular recognition, but few reviews pay attention to aptamer-based regulation of biological functions. Here, we summarize the approaches to enhancing aptamer affinity and the advancements of aptamers in regulating enzymatic activity, cellular immunity and cellular behaviors. Furthermore, this review discusses the challenges and future perspectives of aptamers in target recognition and biological functions regulation, aiming to provide some promising ideas for future regulation of biomolecular functions in a complex biological environment.     

Graded regulation technology for enhanced oil recovery and water shutoff in pore-cavity-fracture carbonate reservoirs

Although a single type of chemical agent (eg, gels, microspheres, surfactants, etc.) has achieved some effects in enhanced oil recovery of carbonate reservoirs, for pore-cavity-fracture carbonate reservoirs, the use of a single type of chemical agent does not perform well. The main objective of this study is to study the effect of different types of chemical agents in enhanced oil recovery of complex carbonate reservoirs. In order to determine the screening principle of chemical agents, the types of water channeling in the North Troyes reservoir were analyzed. For complex fractures, step by step plugging, multi-agent and multi-slug comprehensive intervention is carried out to ensure the plugging of high-permeability channels and inhibit the seepage of large channels. It can plug channeling fracture channel, adjust secondary dominant channel and reduce matrix flow resistance, so as to expand macroscopic swept volume and improve microscopic water flooding efficiency. The results show that it is difficult to comprehensively control water channeling in pore-cave-fracture carbonate reservoir, and the reservoir heterogeneity in the test area can be improved by mixing different types of control and flooding agents and carrying out deep profile control. The plugging rate of gel is 97.18 %, and the oil–water selection ratio is 0.45 in fractured core; the expansion rate of nano - microspheres is more than 3 times; the wetting modifier can improve the imbibition oil displacement efficiency by 14.76%, and the test result shown that nano - microspheres and wetting modifier have good synergistic oil displacement effect. The field application result shown that daily oil production of oil well in the test area increased by 5.0 m³/d and the daily water rate decreased by 19.0% compared with that before the control flooding. The findings of this study can help for better understanding of enhanced oil recovery in pore-cave-fracture carbonate reservoir.     

The Analysis of Phenolic Compounds in Walnut Husk and Pellicle by UPLC-Q-Orbitrap HRMS and HPLC

Husk and pellicle as the agri-food waste in the walnut-product industry are in soaring demand because of their rich polyphenol content. This study investigated the differential compounds related to walnut polyphenol between husk and pellicle during fruit development stage. By using ultra-high performance liquid chromatography-quadrupole-orbitrap (UHPLC-Q-Orbitrap), a total of 110 bioactive components, including hydrolysable tannins, flavonoids, phenolic acids and quinones, were tentatively identified, 33 of which were different between husk and pellicle. The trend of dynamic content of 16 polyphenols was clarified during walnut development stage by high-performance liquid chromatography (HPLC). This is the first time to comprehensive identification of phenolic compounds in walnut husk and pellicle, and our results indicated that the pellicle is a rich resource of polyphenols. The dynamic trend of some polyphenols was consistent with total phenols. The comprehensive characterization of walnut polyphenol and quantification of main phenolic compounds will be beneficial for understanding the potential application value of walnut and for exploiting its metabolism pathway.