煤岩破裂微震信号的小波特征能谱系数分析法

煤岩破裂微震信号是一种时变非平稳信号,具有不可预知性和突发瞬态性,为了提取能够表征微震源信息的有效特征,基于小波理论,选取了适合微震信号的小波基函数,并根据采样定理及Mallat算法确定了小波分解最大尺度,提出了用小波特征能谱系数分析煤岩破裂微震信号波形的状态分析方法。实验结果表明,微震信号与噪声信号有明显不同的小波特征能谱系数分布特征,而且可利用提取的能谱系数作为特征向量表示信号特征。这对于抑制微震信号的不稳定性和同频段的干扰信号,以及后续的特征编码非常有利,为实现煤岩破裂微震信号实时的模式识别打下了重要基础。     

Identification of Entry Inhibitors against Delta and Omicron Variants of SARS-CoV-2

Entry inhibitors against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are urgently needed to control the outbreak of coronavirus disease 2019 (COVID-19). This study developed a robust and straightforward assay that detected the molecular interaction between the receptor-binding domain (RBD) of viral spike protein and the angiotensin-converting enzyme 2 (ACE2) receptor in just 10 min. A drug library of 1068 approved compounds was used to screen for SARS-CoV2 entry inhibition, and 9 active drugs were identified as specific pseudovirus entry inhibitors. A plaque reduction neutralization test using authentic SARS-CoV-2 virus in Vero E6 cells confirmed that 2 of these drugs (Etravirine and Dolutegravir) significantly inhibited the infection of SARS-CoV-2. With molecular docking, we showed that both Etravirine and Dolutegravir are preferentially bound to primary ACE2-interacting residues on the RBD domain, implying that these two drug blocks may prohibit the viral attachment of SARS-CoV-2. We compared the neutralizing activities of these entry inhibitors against different pseudoviruses carrying spike proteins from alpha, beta, gamma, and delta variants. Both Etravirine and Dolutegravir showed similar neutralizing activities against different variants, with EC50 values between 4.5 to 5.8 nM for Etravirine and 10.2 to 22.9 nM for Dolutegravir. These data implied that Etravirine and Dolutegravir may serve as general spike inhibitors against dominant viral variants of SARS-CoV-2.     

基于CAD/CAE/LOM技术的卫生陶瓷种型的开发工艺

卫生洁具是结构最为复杂的陶瓷产品之一,其新产品开发一直沿用传统的手工制作工艺,产品质量低、开发周期长、成本高。针对这一情况,借助CAD/CAE/LOM技术对传统开发工艺的关键环节进行改造研究,实践了一条数字化开发的新途径。实践表明:卫生陶瓷产品的数字化开发工艺切实可行,为卫生陶瓷品种花色的多样化、个性化提供了现代化开发手段。     

相容剂对NBR/PP共混型TPE的影响

研究了4种增容剂,氯化聚乙烯（CPE）,高氯化聚乙烯,马来酸酐接枝聚丙烯（MP）和氯化丙烯（CPP）对丁腈橡胶／聚丙烯（NBR／PP）共混型热塑性弹性体（TPE）物理机械性能的影响,结查表明,CPP是NBR／PP的理想增容剂,当CPP用量为6份时,NBR／PP共混体体系具有优良的热塑性,拉伸强度13．8MPa,扯断伸长度290％,压缩永久变形32％,共混物的相容性与透射电镜的分析结果一致。     

丁苯胶乳_苯乙烯_甲基丙烯酸甲酯核壳乳液接枝共聚的研究

以过氧化苯甲酰(BPO)-Fe~(2+)为引发体系,硬脂酸钾和歧化松香酸皂为乳化剂,硫醇为调节剂,于600mL釜内、70℃下进行丁苯胶乳-苯乙烯-甲基丙烯酸甲酯(SBR-S-MMA)的核壳乳液接枝共聚。研究认为本体系的反应机理为:Fe~(2+)与乳化剂结合为部分油溶性化合物,再与溶解在乳胶粒中的BPO反应,生成自由基与Fe~(3+),Fe~(3+)被雕白块还原为Fe~(2+)后完成一个循环。在乳胶粒相产生的自由基与单体反应或进攻橡胶链,从而引起链引发和链增长反应。S和MMA接枝聚合的初始速率(R_(PO))与[BPO]~(0.5)成正比,R_(PO)随反应温度的升高而增大,随硫醇用量的增加而减小。该体系S和MMA两步接枝反应的表观分解活化能分别为16.56kJ/mol和17.50kJ/mol。     

Synthesis of graft copolymers from a linear polyolefin through a combination of coordination polymerization and atom transfer radical polymerization

This article reports on a facile route for the preparation of methyl acrylate and methyl methacrylate graft copolymers via a combination of catalytic olefin copolymerization and atom transfer radical polymerization (ATRP). The chemistry first involved a transforming process from ethylene/allylbenzene copolymers to a polyolefin multifunctional macroinitiator with pendant sulfonyl chloride groups. The key to the success of the graft copolymerization was ascribed to a fast exchange rate between the dormant species and active radical species by optimization of the various experimental parameters. Polyolefin‐g‐poly(methyl methacrylate) and polyolefin‐g‐poly(methyl acrylate) graft copolymers with controlled architecture and various graft lengths were, thus, successfully prepared under dilute ATRP conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of nonuniform sintering on mechanical and thermal properties of silica-based ceramic cores

During sintering of the silica-based ceramic core of turbine blades, a phenomenon called “nonuniform sintering” occurs that negatively affects the thermal and mechanical properties of the core. Standard samples of silica-based core were prepared by an injection molding method and sintered with alumina backfilling powder with different sodium contents. The effect of sodium content on the nonuniform sintering of silica-based cores and the thermal and mechanical properties was evaluated. Results show that the sintering level and the content of α-cristobalite in the surface layer are significantly higher than that of the sample interior. A considerable number of microcracks are found in the surface layer due to the β to α-phase transition of cristobalite. As the sodium content in the alumina powder decreases, the level of the nonuniform sintering and the amount of crystallized cristobalite in the surface layer decrease, which is beneficial to the thermal expansion and flexural strength at ambient temperature. The flexural strength and thermal deformation at high temperature are improved by reducing the surface cracks, but deteriorated with the decrease of the cristobalite crystallization when the surface cracks are macroscopically invisible.

     

黄姜资源清洁高效利用研究进展

黄姜皂素是合成甾体类药物的重要中间体,传统的皂素生产工艺废液、废渣污染重,而且造成资源浪费。简介了黄姜皂素的用途与传统生产工艺,重点对主产皂素且联产鼠李糖、黄色素等多种产品的黄姜清洁高效利用工艺进行了综述。     

EGSB反应器处理酒精废水启动方法

EGSB(Expanded Granular Sludge Bed,膨胀颗粒污泥床)厌氧反应器虽处理能力大、效率高、抗冲击能力强,但启动较困难,若操作不当,易发生酸化现象,致使启动失败。特别是采用絮状污泥接种情况下,EGSB启动时间较长。采用城市污水处理厂厌氧消化污泥(絮状)接种,在启动过程中,合理控制升温速度、选择恰当的启动负荷、严格控制出水pH值和挥发酸,避免反应器酸化,可有效缩短EGSB反应器启动时间并取得较好处理效果。     

Analysis of EPA and DHA and distinction between fish oils and concentrates

Fish oil is the major dietary source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Adequate dietary intake of these n‐3 PUFA is beneficial to reduce the risks of cardiovascular mortality, prostate cancer, and neurological disorders in children and adults. There is a surge in demand for fish oil in the functional food market. Microencapsulation of fish oil is the trend to improve its stability and sensory quality. The EPA and DHA content of the fish oil products may vary markedly from the label due to their susceptibility to oxidation. Quick and reliable methods other than the AOAC BF₃ method have been exploited to quantify EPA and DHA in the encapsulated fish oil and the microencapsulated powdered products such as infant formula. This article describes a method to differentiate the ethyl‐ester form from the TAG form of EPA and DHA in encapsulated fish oil which may be a mixture of natural triacylglycerol enriched with ethyl esterified EPA and DHA. A method is recommended due to the difference in apparent potency of these two esterified forms, which may be a concern in infant formula and elsewhere.