Exogenous Spermidine Alleviates Low Temperature Injury in Mung Bean (Vigna radiata L.) Seedlings by Modulating Ascorbate-Glutathione and Glyoxalase Pathway

The role of exogenous spermidine (Spd) in alleviating low temperature (LT) stress in mung bean (Vigna radiata L. cv. BARI Mung-3) seedlings has been investigated. Low temperature stress modulated the non-enzymatic and enzymatic components of ascorbate-glutathione (AsA-GSH) cycle, increased H₂O₂ content and lipid peroxidation, which indicate oxidative damage of seedlings. Low temperature reduced the leaf relative water content (RWC) and destroyed leaf chlorophyll, which inhibited seedlings growth. Exogenous pretreatment of Spd in LT-affected seedlings significantly increased the contents of non-enzymatic antioxidants of AsA-GSH cycle, which include AsA and GSH. Exogenous Spd decreased dehydroascorbate (DHA), increased AsA/DHA ratio, decreased glutathione disulfide (GSSG) and increased GSH/GSSG ratio under LT stress. Activities of AsA-GSH cycle enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) increased after Spd pretreatment in LT affected seedlings. Thus, the oxidative stress was reduced. Protective effects of Spd are also reflected from reduction of methylglyoxal (MG) toxicity by improving glyoxalase cycle components, and by maintaining osmoregulation, water status and improved seedlings growth. The present study reveals the vital roles of AsA-GSH and glyoxalase cycle in alleviating LT injury.     

含磷胺类固化剂／环氧树脂固化体系性能研究

研究了含磷胺类固化剂/环氧树脂体系的阻燃性、反应活性及其固化过程。结果表明,含磷脂肪胺及芳香胺固化的环氧树脂均具有较好的阻燃性,其中含磷芳香胺在环氧树脂中尤具有提高相容性及较显著地降低固化温度的特点。此外,含磷胺类固化剂与环氧树脂的固化过程具有明显的阶段性,本文对不同温度阶段的反应机制作了讨论。     

聚胺分子量对其与淀粉的复合物在再生浆上作用效果的影响

本文考察了聚胺（CPA）的分子量对淀粉／CPA复合物在废纸箱再生浆上作用效果的影响。结果表明，淀粉／CPA混合糊液对再生浆具有显著的纸力增强、助留与助滤效果。分子量为120万的CPA作用效果最好。淀粉／CPA复合物添加量小于3％时，淀粉几乎百分之百吸附在再生浆上。1．5％的淀粉／CPA复合物添加时，纸页裂断长增加23．9％，再生浆的打浆度下降46％，留着率提高了5．8％。     

保坍型聚羧酸系高效减水剂研究进展简

本文就保坍型聚羧酸减水剂的类型及作用机理进行了综述,为保坍型聚羧酸减水剂的进一步研究指明方向.     

聚胺抑制剂黏度和阳离子度与页岩相对抑制率的关系

采用开环聚合反应制备了聚胺页岩抑制剂,考察了聚胺相对分子质量（运动黏度）和阳离子度,以及其在钻井液中的质量分数对其页岩抑制性能的影响,并采用XRD方法测定了聚胺处理前后黏土的层间距。结果表明,聚胺具有良好的页岩抑制性能,钻井液中聚胺质量分数越大,相对抑制率越高,经其处理后的黏土层间距先减小后趋于恒定;随着聚胺相对分子质量（运动黏度）的增加,相对抑制率先增大后略有下降,黏土层间距不断增大后趋于缓和;随着聚胺阳离子度的增加,相对抑制率先增大后趋于缓和,黏土层间距呈先快速增加后略有下降的趋势。聚胺运动黏度在304～1940mm²/s、阳离子度在0.750～3.603 mmol/g范围时可以基本满足页岩抑制剂的要求。     

一种新型巯基胺型羧酸螯合树脂的制备与表征

以环硫氯丙烷和多乙烯多胺为原料,通过交联反应合成巯基胺型树脂(PA树脂).然后用氯乙酸对PA树脂进行改性,合成巯基胺型羧酸螯合树脂(PAC树脂),并通过傅里叶红外光谱仪(FTIR)和热重分析仪(TG)对其结构和热稳定性进行表征.研究溶胀时间、介质中含水量、物料比对反应的影响,获得了较佳的工艺条件.结果表明:以三乙烯四胺为原料合成的PAC3树脂的弱酸交换容量最高,达到3.53 mmol/g.     

国内外黏土水化抑制剂研究现状与发展趋势

黏土水化抑制剂在钻井液中的添加可有效降低钻井事故发生,但存在效果不明显、抗温性能尚待提高等缺点。本文简述了国内外黏土水化抑制剂研究现状并分析了其发展趋势。从研究历程来看,黏土水化抑制剂大体上经过了从无机离子型向有机铵（胺）型过渡并逐步成熟于聚合物型的过程。从最新研究结果来看,聚醚胺型抑制剂为主流研究对象,由此形成的高性能水基钻井液在国内外广泛应用;超支化聚合物型抑制剂因具有体型结构而具有较好抗温、抗盐性能而颇具发展优势;传统共聚物型抑制剂分子量大,在高温高密度钻井液中难以适用,仍有改进空间。指出了今后发展趋势是充分利用生物质资源,开发绿色、环保高效的黏土水化抑制剂;研究低聚物抑制剂,提高抑制剂的抗温性、普适性和一剂多效性;摆脱传统钻井液处理剂之间化学作用力观念束缚,探索超支化抑制剂的开发,积极有效结合纳米技术与钻井流体之互补点,以促进钻井液及相关技术发展。     

Improved fracturing fluid using: Organic amino boron composite crosslinker with B?N covalent bond

In order to create an improved fracturing fluid, an organic amine boron composite crosslinker ( ABC-1 ) was prepared from boric acid, triethylenetetramine, ethylene glycol, and mannitol. It has no irritating smell and its synthesis is simple, making it suitable for large-scale field applications. To illustrate the advantages of the new crosslinker, it was compared to the organic borate crosslinker prepared from boric acid, ethylene glycol, and mannitol. The sand-carrying capacities, micronetwork structure, and rheological behaviors of fluids with these crosslinkers were investigated at 90, 100, and 110 °C. The results show that the additional B N r covalent bond in the ABC-1 crosslinker leads to the formation of a denser network structure making it possible to reduce the amount of thickener by about 10%. The temperature resistance could also be enhanced at least 10 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47675.     

环氧树脂室温固化用柔性固化剂的制备与性能研究

首先将聚醚多元醇和甲基丙烯酸甲酯(MMA)进行酯交换反应,然后利用多元胺与烯双键的加成反应原理,将多乙烯多胺与甲基丙烯酸酯进行反应,合成了含甲基丙烯酸聚醚多元醇酯柔性基团的新型环氧树脂室温固化剂。通过FT-IR等方法对产物结构进行表征,探讨并优化了各种反应条件,最后考察了该柔性固化剂对环氧树脂性能的影响。研究结果表明,柔性固化剂合成反应的优化条件是n(聚醚多元醇)∶n(MMA)为1∶5,n(催化剂)∶n(聚醚多元醇+MMA)为2∶100,n(聚醚多元醇酯)∶n(多乙烯多胺)为1∶2.0,反应时间为8h;在此条件下所得固化剂的产率和收率分别为96.3%和96.38%;改性固化剂/环氧树脂体系的凝胶时间仅为29min,拉伸剪切强度达到30MPa。