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961.
962.
Zhigang Wu Guanben Du Ming Cao Xuedong Xi Jiankun Liang 《Journal of Adhesion Science and Technology》2016,30(24):2655-2666
The characteristics of UF resin prepared with concentrated formaldehyde were studied in this paper. With the molar ratio F/U = 1.1, the UF resin prepared with concentrated formaldehyde showed better mechanical properties than that with formalin. The 13C-NMR and FTIR results indicated that there were more methylene groups, ether groups and urons in a UF resin system prepared with concentrated formaldehyde than those in a normal UF resin. The differential scanning calorimetry and DMA results showed that the curing temperature of UF resin with concentrated formaldehyde was lower than that of a normal UF resin. UF resin with concentrated formaldehyde showed worse thermal stability and higher thermal decomposition temperature. 相似文献
963.
本文主要研究了三元乙丙橡胶(EPDM)/氯磺化聚乙烯(CSM)共混胶性能,通过添加增容剂氯化聚乙烯(CPE)和乙烯-醋酸乙烯酯(EVM)、交联助剂甲基丙烯酸锌(ZDMA)和三(甲基丙烯酸)三羟甲基丙烷酯(TMPTMA)来改善EPDM/CSM共混胶的相容性,对比分析EPDM/CSM共混胶的物性、动态力学性能和微观相态。结果表明,随着CSM用量的增加,CSM/EPDM共混胶拉伸强度明显下降,EPDM与CSM相容性不良;加入CPE、EVM、ZDMA、TMPTMA后,共混胶拉伸强度、撕裂强度都增加,硬度也都不同程度增大,加入ZDMA的共混胶拉伸强度提高最大;加入CPE、EVM、ZDMA、TMPTMA后,EPDM 与CSM共混胶的相容性稍有改善,共混胶阻尼曲线中间的“平台区”都有所下降;ZDMA改善EPDM/CSM共混胶相容性要比其它组分好。 相似文献
964.
通过对水质变化时铸铁腐蚀速率与铁释放的对比,研究垢层对铸铁腐蚀的影响作用。结果表明,改变水的硬度和拉森指数(LR),对铸铁的腐蚀速率与铁释放均有明显影响;低硬度水质条件下形成的管垢以较易分解和转化的Fe(OH)_3为主,而较为稳定的Fe_3O_4含量较低,在硬度或LR改变时,管垢破坏严重,铸铁基底腐蚀加剧;高硬度水质下形成的管垢较为致密,表面覆盖大量的CaCO_3,且含有较多Fe_3O_4和FeOOH,管垢整体结构稳定,在硬度或LR改变时,能抑制铸铁基底的进一步腐蚀。 相似文献
965.
Affinity‐tuned peroxidase‐like activity of hydrogel‐supported Fe3O4 nanozyme through alteration of crosslinking concentration 下载免费PDF全文
In this work, we evaluated the effect of crosslinking concentration on the affinity of poly (2‐acrylamido‐2‐methyl‐1‐propansulfonic acid) (PAMPS) hydrogel‐supported Fe3O4 nanozyme towards substrates (tetramethylbenzidine (TMB) and H2O2). The peroxidase‐like catalytic activity of PAMPS/Fe3O4 nanozyme was discussed with respect to crosslinking concentration of PAMPS hydrogel for the oxidation of TMB in the presence of H2O2 at room temperature. High catalytic activity was achieved due to good dispersion of Fe3O4 nanozyme in the hydrogel network and strong affinity of PAMPS hydrogel‐supported Fe3O4 nanozyme towards substrates. The affinity between the hydrogel‐supported Fe3O4 nanozyme and substrates can be improved by regulating the crosslinking concentration of PAMPS hydrogel without other trenchant experimental conditions. In addition, the result indicated that H2O2 can be detected even at a concentration as low as 1.5 × 10?6 mol L?1 with a linear detection range of 1.5–9.8 × 10?6 mol L?1. Such investigations not only showed a new approach to improve the affinity and peroxidase‐like activity of Fe3O4 nanozyme, but also verified its potential application in bio‐detection and environmental chemistry. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43065. 相似文献
966.
Amphiphilic acrylate copolymer fatliquor for ecological leather: Influence of molecular weight on performances 下载免费PDF全文
With increasing demand for ecological leather, ecological fatliquors with good comprehensive properties are getting more and more attention. The amphiphilic acrylate copolymer containing both hydrophilic (carboxyl) and hydrophobic (long alkyl) groups is one of the main alternatives to conventional fatliquors. In this paper, a series of poly(acrylic acid‐co‐stearyl acrylate) with different relative molecular weights were prepared, and the influence of the molecular weight on their application performances were evaluated. The results show that lower relative molecular weight of copolymers is conducive to the penetration and absorption, and it improves the softness and fiber separation of leather. When the number average molecular weight (Mn) of copolymer is higher than 25,000, its penetration and absorption become worse and the resulting leather feels hard. In addition, the amphiphilic acrylate copolymers can impart excellent oxidation resistance and transference resistance to leather, which is a considerable improvement over the conventionally retanned and fatliquored leather. The copolymer has great penetration and absorption ability when Mn is within the range of 9,000–15,000, and it gives leather excellent integrated properties, such as filling, softness, mechanical strength, extraction resistance, and oxidation resistance, which can meet requirements of ecological leather. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43440. 相似文献
967.
Dietary Arachidonic Acid Has a Time-Dependent Differential Impact on Adipogenesis Modulated via COX and LOX Pathways in Grass Carp Ctenopharyngodon idellus 下载免费PDF全文
In this study, we explored the function of arachidonic acid (ARA) in adipogenesis in the grass carp (Ctenopharyngodon idellus) using in vivo and in vitro models. An 8‐week feeding trial was performed using three isonitrogenous and isoenergetic purified diets: ARA‐free, ARA, and ARA + acetylsalicylic acid [ASA, a cyclooxygenase (COX) inhibitor]. Fish were sampled after 4 and 8 weeks of feeding. Results showed that ARA‐fed fish had a significantly lower intraperitoneal fat index (IPFI) and smaller adipocytes; these decreases were reversed by ASA after 8 weeks of feeding. Nevertheless, at week 4, the IPFI and adipocyte size were higher in the ARA group, and they were comparable to those of fish fed ARA + ASA. To further investigate the influence of ARA on adipocyte differentiation, confluent pre‐adipocytes of grass carp were incubated with ARA for 3 days. This in vitro experiment demonstrated that ARA promoted adipogenesis in a dose‐dependent manner. Pre‐treatment with the lipoxygenase (LOX) inhibitor nordihydroguaiaretic acid attenuated the pro‐adipogenic function of ARA. However, after treatment with ARA for 8 days, adipocytes had a lower lipid content than cells treated with oleic acid, and ASA could suppress this effect. We thus revealed the dual function of ARA in adipogenesis in grass carp. The LOX pathway may play a key role in pro‐adipogenesis after short‐term treatment with ARA, whereas the COX pathway is possibly responsible for the inhibition of adipogenesis after long‐term treatment. 相似文献
968.
Preparation of glucose‐sensitive and fluorescence micelles via a combination of photoinitiated polymerization and chemoenzymatic transesterification for the controlled release of insulin 下载免费PDF全文
Xiangxiang Du Guohua Jiang Lei Li Wentong Yang Hua Chen Yongkun Liu Qin Huang 《应用聚合物科学杂志》2016,133(9)
Glucose‐sensitive and fluorescence copolymer micelles were designed and prepared via a combination of photoinitiated polymerization and enzymatic transesterification. The water‐soluble photoinitiator and emulsifier 2‐oxooctanoic acid self‐polymerized dimer molecules under UV irradiation were characterized by mass spectrometry. The fluorescence dye (9‐anthracene alcohol) and biocompatible hydrophilic chains [poly(ethylene glycol)] were introduced to the polymer chains during the photopolymerization and enzymatic transesterification processes. The as‐prepared copolymers were confirmed by 1H‐NMR spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and dynamic light scattering. The resulting copolymers exhibited excellent glucose sensitivity and stability against protein. The optical fluorescence properties of the copolymer micelles were investigated with fluorescence spectrophotometry, fluorescence microscopy, and confocal laser scanning microscopy. Because of the amphiphilic feature, the micelles could be self‐assembled and used to load insulin. The controlled release of insulin was evaluated and was triggered by glucose in vitro. This study provided a new strategy for fabricating functional carriers as self‐regulated insulin‐release systems. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43026. 相似文献
969.
Spectral and Laser Properties of Yb:LuAG Transparent Ceramics Fabricated by Tape Casting Method 下载免费PDF全文
Chaoyang Ma Fei Tang Jiangfeng Zhu Miaomiao Du Xuanyi Yuan Yang Yu Ke Wang Zicheng Wen Jiantao Zhang Jiaqi Long Wang Guo Yongge Cao 《Journal of the American Ceramic Society》2016,99(10):3267-3272
Yb3+‐doped LuAG laser ceramics with different Yb3+‐doping concentrations were successfully fabricated by nonaqueous tape casting method and vacuum sintering technology. XRD patterns and SEM morphologies of the ceramics were presented. The optical in‐line transmittance of the Yb‐doped LuAG ceramics was about 83% at 1030 nm. The fluorescence lifetime of annealed and unannealed ceramic samples was compared. From the spectroscopic properties, it can be seen that the ceramics had a large emission cross section of 2.9 × 10?20 cm2 with a FWHM of about 7.2 nm at 1030 nm. Under 100% population inversion, the maximum gain coefficient was estimated to be 12.4 cm?1 at 1030 nm. With a fiber‐coupled diode laser as pump source, CW laser at 1030 nm was demonstrated and the maximum output power of 338.9 mW was achieved with a slop efficiency of 19%. A tuning range from 1028 to 1036 nm was obtained. 相似文献
970.
Data‐driven mathematical modeling and global optimization framework for entire petrochemical planning operations 下载免费PDF全文
Xin Xiao Christodoulos A. Floudas Baoguo Zhao Guangming Du Xin Su Hongwei Liu 《American Institute of Chemical Engineers》2016,62(9):3020-3040
In this work we develop a novel modeling and global optimization‐based planning formulation, which predicts product yields and properties for all of the production units within a highly integrated refinery‐petrochemical complex. Distillation is modeled using swing‐cut theory, while data‐based nonlinear models are developed for other processing units. The parameters of the postulated models are globally optimized based on a large data set of daily production. Property indices in blending units are linearly additive and they are calculated on a weight or volume basis. Binary variables are introduced to denote unit and operation modes selection. The planning model is a large‐scale non‐convex mixed integer nonlinear optimization model, which is solved to ε‐global optimality. Computational results for multiple case studies indicate that we achieve a significant profit increase (37–65%) using the proposed data‐driven global optimization framework. Finally, a user‐friendly interface is presented which enables automated updating of demand, specification, and cost parameters. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3020–3040, 2016 相似文献