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81.
垂向多层发育的致密油藏常采用缝网压裂进行开采,从而改善储层渗透率,提高油井产量。为此建立直井多层缝网压裂不稳定渗流数学模型,压裂后各层划分为人工裂缝区、改造区和未改造区。绘制分析Blasingame产量递减典型曲线,曲线分为7个流动阶段,总裂缝长度一定时,裂缝半长短的储层流体渗流率先到达未改造区,流体渗流阻力大,Blasingame曲线靠下;总改造体积一定时,各层改造体积差异越大,Blasingame曲线越靠下。用所建立的模型,对实测生产资料进行解释,获得各层裂缝半长、改造区渗透率等相关地层参数,该模型对进行多层缝网压裂直井产量分析具有指导意义。 相似文献
82.
83.
Ruopei Xu Yue Qiu Siyi Tang Cheng Yang Yu Dai Dajie Zhang Yue Gao Kexiong Gao Longbo Luo Xiangyang Liu 《大分子材料与工程》2021,306(5):2000814
High performance fibers with high strength and toughness have great potential in composites, but contradiction between tensile strength and elongation at break makes the preparation to become a current challenge. Herein, an asymmetric structure of more flexible diamine, 3,4′-diaminodiphenyl ether (3,4′-ODA), is introduced into heterocyclic aramid (PBIA) fibers to replace rigid symmetric p-phenylenediamine (PDA). By studying the properties of copolymer (mPEBA) fibers with different ratios of diamine, it is found that the mPEBA fiber reached the optimal mechanical properties with the 30% content of 3,4′-ODA. Compared with homopolymerized heterocyclic aramid fibers, the tensile strength and elongation at break of mPEBA fiber are improved by 26.2% and 38.7%, respectively. Results of X-ray diffraction show that the introduction of 3,4′-ODA structure can increase stretchability of mPEBA fibers, improving the orientation degree during hot-drawing. Molecular dynamics simulations confirm that 3,4′-ODA structure undergoes a conformation transformation to form a straightened chain during hot-drawing, while symmetrical 4,4′-diaminodiphenyl ether (4,4′-ODA) cannot form the same conformation. The misplaced-nunchaku structure is formed based on the special meta-para position of 3,4′-ODA, achieving the synergy of high strength and high toughness. 相似文献
84.
Birong Zeng Kaibin He Haiyang Wu Jianyu Ye Xianghong Zheng Weiang Luo Yiting Xu Conghui Yuan Lizong Dai 《大分子材料与工程》2021,306(6):2100012
A zirconium hybrid polyhedral oligomeric silsesquioxane derivative (Zr–POSS–bisDOPO) is synthesized by the corner-capping and Kabachnik–Fields reactions. It is characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR), and then used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) to endow epoxy resin (EP) with flame retardancy. The flame retardancy, thermal stability, and mechanical properties of the cured EP/Zr–POSS–bisDOPO composites are investigated. The results show that when Zr–POSS–bisDOPO is added by 5–7 wt%, the EP/Zr–POSS–bisDOPO composites pass the UL-94 V-0 rating test. In addition, they have a better flame-retardant effect than pure EP. The combination of Zr atom embedded in the Si O cubic cage and the two phosphaphenanthrene substituent groups in one corner of cubic cage is expected to realize the Zr/Si/P ternary intramolecular hybrid synergistic effect and achieve the possibility of dispersing metal–POSS cages at a sub-micrometer-scale level into polymer matrix. It also proves that Zr–POSS–bisDOPO produces phosphorus-containing free radicals and terminates the chain reactions in gas phase. Meanwhile the Si O Si and Zr O units are retained in the solid phase, which promote the char formation and enhance the flame retardancy. This kind of Zr-doped POSS will be helpful for developing the new metal–POSS hybrid flame-retardant and polymer composites. 相似文献
85.
The design and application of bioderived flame retardants have been widely conducted to meet the concept of green and sustainable development. Here, self-assembly technique is used to prepare core–shell bioderived additives by using β-FeOOH as the core and polydopamine (PDA)/tannic acid (TA) bilayer as the shell, following adsorption of nickel ions to enhance the thermal stability, flame retardancy, and mechanical properties of epoxy resin (EP). The molecular structure of biobased resources is rich in hydroxyl groups and carbon content, which can be dehydrated and carbonized during combustion and promote the formation of robust protective char layer. With the addition of 5 wt% β-FeOOH@PTNi, the EP composites can pass V-0 rating in the UL-94 test. The peak heat release rate and total heat release decrease by 28.4% and 17.4% compared with pure EP. The bioderived nanorods can capture the oxygen free radicals, contributing to flame retarding in gaseous phase. Thus, the release of high-toxic CO and flammable gaseous is significantly suppressed. Besides, the storage modulus of EP composites increases by 16.0% with the addition of 5% β-FeOOH@PTNi compared with pure EP. This work provides a sustainable methodology for the design of bioderived flame retardants for EP. 相似文献
86.
Ning Wang Jun Chen Qi Zhou Lianzhou Jiang Liqi Wang Yingjie Dai Dianyu Yu Walid Elfalleh 《European Journal of Lipid Science and Technology》2021,123(6):2000091
Crude wax extracted from rice bran oil (RBO) is used to improve the oleogel properties and oxidative stability of RBO. The effect of crude rice bran wax (CrBW) on the formation characteristics and oxidative stability of oleogels is discussed. The results show that oleogels can be formed with 7.0 wt% CrBW at 20 °C. As the concentration of CrBW increases from 7.0 to 11.0 wt%, the hardness and solid fat content (SFC) of the oleogels increase significantly, and the oleogels are primarily β' crystals. Moreover, oleogel crystals formed with 5 and 7 wt% CrBW are flocculent; when the amount included is 9%, the oleogel crystals are transformed into long dendrites, and the density rises. After 90 days of storage at 20 °C, the peroxide value of oleogels formed with 9.0 wt% CrBW slowly rises from 3.21 to 6.52 mmol kg−1. Practical Applications: Oleogels prepared here by CrBW and RBO are an innovative structural lipid without trans fats. Useful information on the rich fats and nutrients in CrBW is provided, which reduces the production cost and improves the industrial production capacity. 相似文献
87.
过氧化氢(H2O2, 俗称双氧水), 由于其强氧化性常用作漂白剂、消毒剂, 同时也作化工原料。目前工业上生产过氧化氢的主要方法为蒽醌法, 全球近99%的产品均通过蒽醌法制得。研究具有高活性、高选择性及经济性的催化剂是合成过氧化氢所面对的最具挑战性的课题, 同时也是工业催化领域的研究热点之一。主要针对蒽醌法制过氧化氢催化剂, 综述了各种活性组分、载体及助剂在蒽醌加氢催化剂中的研究进展, 并简单探讨了各种活性组分的优缺点, 概括了各种载体、助剂的作用, 以期对过氧化氢催化剂的合成制备提供一些有益的启示。 相似文献
88.
DD—921钢铁常温发黑剂的研制和应用 总被引:4,自引:0,他引:4
研究了钢铁常温发黑过程的成膜机理,各组分之间的作用以及相互之间的影响,着重分析了常温发黑的优缺点,工艺控制参数以及经济性。 相似文献
89.
90.
大型钛合金压气机盘超塑性等温锻造模具结构及工艺参数实验研究 总被引:3,自引:0,他引:3
通过超塑拉伸和压缩试验,用金属铅进行模拟实验,探讨了大型TC11合金压气机盘超塑性等温锻造的工艺参数,模具结构,锻坯形状尺寸及润滑剂的选择、并讨论了其模具材料及加热方式的选择。 相似文献