共查询到20条相似文献,搜索用时 15 毫秒
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Dorota Rutkowska-Zbik Agnieszka Drzewiecka-Matuszek Malgorzata Witko 《Topics in Catalysis》2014,57(10-13):946-952
The present brief review aims at elucidation of the parameters affecting the properties and reactivity of high valent iron(IV) oxo porphyrin complexes, being models of compound II reactive intermediate known from biochemistry of cytochromes and peroxidases. The stress is put on the influence of the axial ligand and porphyrin ring substituents, with special attention on implications for their catalytic activity. 相似文献
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Célia R. A. Maltha Luiz C. A. Barbosa Marco A. B. Azevedo Jorge L. Colodette 《木材化学与工艺学杂志》2013,33(2):103-120
Abstract This study investigated the chemical composition of the dichloromethane and acetone extracts of eucalypt pulp across D(EP)DP and AZDP bleaching sequences by gas chromatography-mass spectrometry (GC-MS). The bleaching stages led to the partial removal and to several oxidative transformations of fatty acids and sterols, the main lipophilic extractives found in the unbleached pulp. The pulp samples were bleached to 90–91% ISO by D(EP)DP and AZDP sequences and their brightness stability and chemical characteristics determined. The effect of aging on brightness was investigated. The AZDP bleaching sequence resulted in pulps of higher brightness stability. Furoic structures representing the main acid degradation products of HexA are suggested as the actual intermediates that cause yellowing by forming colored compounds. The AZDP process removed larger amounts of HexA across bleaching. 相似文献
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以邻氨基酚为原料,经过酰化、偶合反应合成了一系列不同碳链长度的3′ 脂肪酰氨基 4′ 羟基偶氮苯 4 磺酸,它们具有表面活性剂和偶氮染料的特征结构。这些褐色产物溶于强碱性溶液,其中脂肪酰氨基为12,14和16碳的产物具有表面活性,是有色的表面活性剂。其CMC以及CMC下的表面张力值均随着碳链增加而降低,由12碳酰氨基产物的0 0023mol/L及56 4mN/m下降到最低的16碳酰氨基产物的0 0009mol/L及48 6mN/m,表现出较好的表面活性,符合典型表面活性剂的规律。 相似文献
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通过偶合反应合成了4个不同碳链长度的3′-脂肪酰胺基-4′-羟基偶氮苯-2-(4-磺基苯偶氮基)-4-磺酸(BAS),这些化合物同时有表面活性剂和双偶氮染料的结构,其中,脂肪酰胺基为10(C10),12(C12)和14(C14)个碳的产物有较好的表面活性,是有色的表面活性剂。表面活性最好的C14 BAS的γCMC为52.7 mN/m,最低表面张力为50.2 mN/m。虽然BAS的上染率较低(7%~11%),染后的布块颜色较浅,但染色布吸附食用油后,用水洗脱的油量明显比白布多,是其2~3倍。 相似文献
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复方干扰素合剂抗鼻病毒的研究 总被引:1,自引:0,他引:1
为了进一步确定黄芪、干扰素对防治感冒的效果,用人α2b型基因工程干扰素和黄芪组成复方干扰素合剂,以14、39型鼻病毒为模型,在不同人二倍体细胞培养上研究复方干扰素合剂的抗鼻病毒作用。结果表明,0.3%的黄菌注射液对人α2b型基因工程干扰素抗14型和39型鼻病毒确有协同作用,可以提高干扰素抗鼻病毒感染的能力达1.5倍左右。经与VSV病毒对比试验,证明鼻病毒对人α2b型基因工程干扰素的抗病毒作用是很敏感的。复方干扰素合剂在4、22和37℃存放18个月后.抗病毒滴度未见明显下降。如采用10万单位干扰素与黄芪组成合剂,可以产生25万单位干扰素治疗感冒的效果,这与志愿者攻击试验的所用剂量相当。 相似文献
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分析防老剂在模拟轮胎生产工序工艺条件下的挥发特性,并将其挥发性物质与整车厂家关注的挥发性有机化合物(VOCs)和REACH法规高度关注的物质(SVHC)清单进行比对;分析不同防老剂组合轮胎胎侧胶,确定胎侧胶的挥发性物质以及挥发量与放置时间的关系,判定影响胎侧胶气味的主要因素。结果表明:在轮胎生产过程中防老剂的VOCs挥发量较小,与受热温度呈正相关性;不同防老剂的稳定性不同,挥发性物质气味也有差异;促进剂是胎侧胶主要挥发性物质的产生体,经高温(80℃)停放一定时间后胎侧胶的挥发量明显减小;加强原材料控制、保证原料供应的连续性和稳定性、优化配方和工艺是减小轮胎VOCs挥发量及气味的方法。 相似文献
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将分别添加1%金属氧化物MgO、CaO、ZnO的聚ε-己内酯(PCL)薄膜放入堆肥和陕西土壤降解液中降解100 d,研究金属氧化物对PCL的降解性和降解前后结晶的影响.采用光学显微镜观察了降解前后薄膜表面形貌的变化.通过WAXD分析了其降解前后结晶度的变化,利用GPC测定了降解过程中PCL的M<,n>和M<,w>/M<,n>的变化.研究结果表明:添加MgO、CaO显著加速了PCL的降解,而添加ZnO对PCL的降解影响不大.金属氧化物的添加提高了PCL的结晶度,对结晶形态没影响,但降解后所有的结晶度均减少. 相似文献
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Yue Xiaopeng Liu Pengjie Xu Yongjian 《Polymer-Plastics Technology and Engineering》2017,56(11):1225-1235
Chemithermomechanical pulp fiber was pretreated by alkali solution to alter the surface characteristics of fibers. The untreated and treated fibers were used to prepare poly(butylene succinate)/chemithermomechanical pulp fiber composites with or without the incorporation of cellulose fatty acid ester (hydroxyethyl cellulose lauric acid ester). X-ray photoelectron spectrum analysis shows that the O/C ratio on the fiber surface increased after alkali treatment, indicating that part of lignin was removed during alkali treatment process. Scanning electron microcopy images indicate that the fiber surface was changed to rough after alkali treatment. The modification effect of hydroxyethyl cellulose lauric acid ester reflects as the improvement of fiber order in matrix, together with the enhancement of interfacial bonding, whereas, the modification effect of alkali treatment is mainly due to the enhancement of interfacial bonding. The integrated mechanical properties of composite prepared by alkali-treated fibers are superior to those of composite prepared by hydroxyethyl cellulose lauric acid ester-treated fibers. The combination of these two modification methods favors the enhancement of tensile and impact strengths of composite. However, in comparison with the composite prepared only by alkali treatment, the flexural strength and modulus would be despaired in a certain degree. When fibers were alkali treated, the shear viscosity of composite exhibited a larger increase, whereas the shear viscosity of composite prepared fibers with hydroxyethyl cellulose lauric acid ester treatment exhibits a slight decrease. 相似文献
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褐煤是煤化程度最低的煤种,为泥炭在适度压力下转变而成,煤化程度低,用作气化原料存在许多缺陷,如高水分、高灰分、熔点变化大、机械强度低、热稳定性差、煤气粉尘含量大、料层透气性差等。但将褐煤提质后制备高浓度水煤浆,再通过水煤浆气化加以利用是褐煤利用的一个新途径。本文通过对褐煤原煤和提质型煤成浆特性的研究,通过级配试验、添加剂试验、成浆浓度试验等,得出褐煤经提质后成浆性可以得到很大的提高,为褐煤应用拓宽了应用领域。 相似文献
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Stephen M. Copley 《The Journal of Adhesion》1974,6(1):139-152
The morphology and properties of an in-situ metallic composite depend on the nature of the interfaces separating its constituent phases. In this paper, four models for these interfaces are considered: coherent, semi-coherent, cusp-oriented and noncoherent. The consequences of each model with respect to composite morphology, load transfer, morphological stability at elevated temperatures and mechanical behavior are discussed. 相似文献
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Stephen M. Copley 《The Journal of Adhesion》2013,89(1-2):139-152
The morphology and properties of an in-situ metallic composite depend on the nature of the interfaces separating its constituent phases. In this paper, four models for these interfaces are considered: coherent, semi-coherent, cusp-oriented and noncoherent. The consequences of each model with respect to composite morphology, load transfer, morphological stability at elevated temperatures and mechanical behavior are discussed. 相似文献
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中国非金属矿物资源丰富,价格低廉,并具有较强的离子交换性、表面吸附性等优良特性,在生活中应用十分广泛。文章介绍了非金属矿物的特点,并详细综述了其在废水处理、天然气及石油钻井、塑料等方面的应用。 相似文献
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Gerhard Drolshagen Francesco Antonio Gianturco J. Peter Toennies 《Israel journal of chemistry》1989,29(4):417-425
The predissociative behavior of the H+3 system is studied from the point of view of purely vibrational coupling between the rotationally-averaged motions of the neutral diatomic and the bound proton. By decoupling the effects of the usual rotational barriers from those induced by the potential strength as a function of relative separations, one is able to see that the vibrational interchannel coupling shows strong propensity and highly nonstatistical propagation among bound levels and that the inner chaotic motion often assumed for this system is mostly controlled by the presence of multiple angular momentum barriers. Tunneling through these multiple rotational momentum barriers appears to be responsible for the slow dissociation seen in spectroscopic experiments. 相似文献
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