天然酯绝缘油改性的研究进展

天然酯绝缘油具有较高的燃点和闪点、优异的天然降解能力和良好的绝缘性能,是矿物绝缘油的绿色替代品.由于其自身的理化特性,将其应用于变电设备还面临着很多挑战.本文综述了天然酯绝缘油的制备工艺,结合天然酯绝缘油的不足之处,从添加剂改性、混合改性、纳米改性及化学改性等方面阐述了天然酯绝缘油的研究成果,并对未来的研究方向进行了展望.     

云关系模式及其应用*

在云变换的基础上,结合非经典关系数据库理论提出了云关系模式,给出了云关系模式的定义,探讨了云关系模式的意义,并将它应用于学生成绩数据库中,改进了目前学生定性评定方法,克服了其中的主观因素,实例证明该方法具有可行性.     

基于文献计量学的水资源承载力研究进展综述

为分析水资源承载力研究发展状况与趋势,本研究以WOS核心合集和中国科学引文数据库文献作为原始数据,利用CiteSpace程序绘制知识图谱,梳理总结了学科知识基础、研究热点.研究结果揭示了水资源承载力领域的演变特征与发展趋势,有助于加深对该领域的整体认识,为我国水资源承载力领域开拓新的研究前沿提供理论参考和借鉴的意义.     

变电站直流系统复合故障处理及防范对策研究

直流系统在变电站中为控制、信号、继电保护、自动装置及事故照明等提供可靠的直流电源.直流系统故障将会导致保护装置误动或拒动,严重影响变电站的安全稳定运行.从某220 kV变电站直流系统多处合环、串电、蓄电池漏液的复合直流系统故障案例出发,在分析直流系统故障起因的同时给出现场故障处理方案,并结合生产实际提出相应的防范措施,对后续类似直流系统复合故障的处理提供参考.     

氟化磷酸钒钠在钠离子电池中的应用进展

钠离子电池具有安全性高、钠资源丰富、成本低等独特优势,引起了人们的广泛关注.构建具有良好电化学性能的钠离子电池的关键之一就是正极材料的选取,氟化磷酸钒钠[Na3V2(PO4)2F3]因其结构稳定性好、离子输运快、工作电位高等特点被认为是一种很有前途的正极材料.但电导率较低,使其电化学性能较差;制备成本较高,阻碍了其大规模应用的发展.综述了在提升Na3 V2(PO4)2 F3电化学性能方面的措施,主要包括改进制备方法、离子掺杂、表面包覆等.为今后高性能Na3 V2(PO4)2 F3的合理设计提供了很好的参考.     

主变方向过流保护拒动原因分析

针对某变电站主变10 kV方向过流保护拒动情况,从保护原理、现场接线、定值设置等方面,分析电流互感器的极性选择及方向元件控制字的设置对短路功率方向的影响,提出规范二次接线、合理设置控制字等防止保护拒动和误动的相关措施,确保方向过流保护动作的正确性.     

Effects of Edible Insect Tenebrio molitor Larva Fermentation Extract as a Substitute Protein on Hepatosteatogenesis and Proteomic Changes in Obese Mice Induced by High-Fat Diet

Mealworms (Tenebrio molitor larva) are an edible insect and a protein-rich food; however, research on mealworms as a substitute protein is insufficient. In this study, mealworm fermentation extract (TMP) was assessed as a replacement for soy protein (SP) in a control diet (CON) or a high-fat diet (HFD) of mice for 12 weeks. TMP substitution reduced body weight, body weight gain, body fat mass (perirenal and mesenteric), fat size, glucose intolerance, and insulin resistance compared to the HFD-SP group. TMP alleviated hepatic steatosis (lipid contents and lipid droplets) in high-fat-fed mice and down-regulated the PPARγ, CD36, and DGAT2 gene levels. Proteomic analysis showed that a HFD for 12 weeks up-regulated 20 proteins and down-regulated 17 proteins in mice fed SP. On the other hand, TMP reversed the protein profiles. TMP significantly down-regulated KHK, GLO1, ATP5H, SOD, and DDAH1 and up-regulated DLD, Mup1, CPS1, Ces3b, PDI, and HYOU1 compared to the HFD-SP group. These proteins are involved in the glucose, lipid, and amino acid metabolism, as well as in oxidative stress and endoplasmic reticulum stress. Thus, substituting SP for TMP helped improve HFD-induced obesity, steatosis, and insulin resistance in mice. These results suggest that TMP is a potential substitute for commonly used protein sources.     

Adenovirus-Mediated Inducible Expression of a PD-L1 Blocking Antibody in Combination with Macrophage Depletion Improves Survival in a Mouse Model of Peritoneal Carcinomatosis

Immune checkpoint inhibitors (ICIs) have demonstrated remarkable efficacy in a growing number of malignancies. However, overcoming primary or secondary resistances is difficult due to pharmacokinetics issues and side effects associated with high systemic exposure. Local or regional expression of monoclonal antibodies (mAbs) using gene therapy vectors can alleviate this problem. In this work, we describe a high-capacity adenoviral vector (HCA-EFZP-aPDL1) equipped with a mifepristone-inducible system for the controlled expression of an anti-programmed death ligand 1 (PD-L1) blocking antibody. The vector was tested in an immune-competent mouse model of colorectal cancer based on implantation of MC38 cells. A single local administration of HCA-EFZP-aPDL1 in subcutaneous lesions led to a significant reduction in tumor growth with minimal release of the antibody in the circulation. When the vector was tested in a more stringent setting (rapidly progressing peritoneal carcinomatosis), the antitumor effect was marginal even in combination with other immune-stimulatory agents such as polyinosinic-polycytidylic acid (pI:C), blocking mAbs for T cell immunoglobulin, mucin-domain containing-3 (TIM-3) or agonistic mAbs for 4-1BB (CD137). In contrast, macrophage depletion by clodronate liposomes enhanced the efficacy of HCA-EFZP-aPDL1. These results highlight the importance of addressing macrophage-associated immunoregulatory mechanisms to overcome resistance to ICIs in the context of colorectal cancer.     

Importance of Low-Temperature Melt-Mixing on the Construction of Stereocomplex Crystallites with Superior Nucleation Efficiency in Asymmetric Poly(l-lactide)/Poly(d-lactide) Blends

The nucleation efficiency (NE) of stereocomplex crystallites (SCs) formed in asymmetric poly(L-lactide)/poly(D-lactide) (PLLA/PDLA) blends is generally unsatisfactory because the competition between stereocomplexation and chain mixing involved in the melt-mixing process can cause low formation efficiency and even severe aggregation of SCs. Herein, it is attempted to achieve high-efficient formation of finely dispersed SCs particles by designing a unique melt-mixing procedure, where the mixing of PLLA with 0.75 wt% PDLA is first performed at elevated temperatures (far above the melting temperature of SCs) to allow the homogeneous mixing of PLLA/PDLA chains and then at a low temperature (slightly above that of homocrystallites) to permit the full stereocomplexation of the premixed chains. It is found that the SCs formed in the blends exhibit unexpectedly low NEs (e.g., 54.5%), much inferior to that (73.6%) in the counterpart without undergoing premixing. This is because the introduction of premixing leads to a remarkable deterioration in the amount of SCs particles formed, despite decreased particle size, highlighting that the direct mixing at low temperatures of 170–180 °C (about 20–30 °C lower than that used in common melt-processing of PLA) is more effective for the construction of SCs with superior NE. The mechanisms for these striking findings are discussed.