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1.
我国海上油田开采起步较晚,大部分油田处于浅水区,因此,在设计管道时,应充分考虑由浅水区波浪引起的管道周围海床渗流力。根据浅水波相关假设,考虑自由水面非线性影响,推导出椭圆余弦波的波面方程,在此基础上进一步得到一个关于速度势的表达式,并根据该表达式得出作用于海床表面的波压公式。考虑海床土的压缩性,推导出一阶近似椭圆余弦波作用下浅水区埋置管道周围海床的渗流压力解析解,最后将计算结果与大型水槽试验及以往研究成果作对比。结果表明,在椭圆余弦波的作用下,由一阶椭圆余弦波理论得到的计算结果与试验结果规律基本一致,与相似工况下的现有理论成果数值基本相同,具有一定的可行性和工程价值。 相似文献
2.
天然气水合物作为一种储量大、无污染的清洁能源近些年受到了广泛关注. 近20年来,中国进行了较大范围的陆海域天然气水合物储层勘探与储量预测.2017年,中国地质调查局牵头对南海神狐海域的天然气水合物进行了基于降压渗流原理的试验性开采.国内外已进行的水合物试采工程面临着气体产量低、出砂较多等问题,其最主要的原因之一是开发过程中沉积物内复杂多相渗流机理尚不明晰.本文综述了平行毛细管模型、Kozeny模型等广泛应用于天然气水合物开发渗流分析的理论模型,对比分析了水合物开发多尺度渗流过程模拟方法,简述了国内外含水合物沉积物渗透率测试、渗流过程中沉积物物性演变以及水合物开采室内模拟等方面的渗流实验进展,总结了矿场尺度的天然气水合物储层开采过程中产气数值模拟手段,展望了多相渗流模型、储层原位含水合物样品室内测试及结构与物性演化、矿场尺度数值模拟与水平井压裂技术等应用研究的未来方向与挑战. 相似文献
3.
Reactions of a,ß‐unsaturated N‐benzenesulfonyl Imine – N‐[(2E)‐3‐phenyl‐2‐propen‐1‐ylidene]benzenesulfonamide with Methyllithium 下载免费PDF全文
α,β‐Unsaturated N‐benzenesulfonyl imine 1 was treated with 1.1 eq methyllithium to afford 1,2‐addition adduct as a sole product. However, when compound 1 was treated with 2 eq MeLi, 1,2‐addition product, benzenesulfonamide derivative 3 and 2H‐1,2‐benzothiazine 1,1‐dioxide derivatives 4 and 5 were isolated. 相似文献
4.
《Physics letters. A》2020,384(26):126672
Ab initio density-functional theory calculations with spin polarization are performed to explore magnetic properties in zigzag green phosphorene nanoribbons (ZGPNRs) with no passivation or edge-saturated by H, OH and O chemical species. It is found that antiferromagnetic order at intra-edges is the most energetically favorable for the pristine and oxygen passivated ribbons, while H- or OH-saturated ZGPNRs show nonmagnetic order. It indicates that edge states arising from the unsaturated bonds are vital for the formation of the magnetic moment in the ZGPNRs. The magnitude of the edge magnetism in the pristine and O-saturated ZGPNRs is comparable to that in zigzag black phosphorene nanoribbons. Electronic band structures, spin densities and spd-orbital projected density of states for the studied pristine and O-passivated ZGPNRs are further analyzed to study their electronic properties. The magnetic and electronic properties discovered in the ZGPNRs may suggest potential applications in future spintronics and electronics. 相似文献
5.
Triflic acid-mediated stereoselective direct lactonization of a variety of α-amino γ,δ-unsaturated carboxylic acid esters and the construction of new γ-butyrolactone structural motifs are reported. Several α-amino γ,δ-unsaturated carboxylic acid esters underwent stereo- and regioselective 1,5-cyclization and afforded a variety of highly substituted homoserine lactone scaffolds having contiguous stereocenters. The direct lactonization of the chiral α-amino γ,δ-unsaturated carboxylic acid esters with triflic acid led to the enantioselective synthesis of the novel homoserine lactones. A plausible mechanism for the direct lactonization of α-amino γ,δ-unsaturated carboxylic acid esters is presented. The stereochemistry of major isomers 3f, 7a, 7b, and 7d was unambiguously established from the X-ray structure analysis. 相似文献
6.
Zaijun Ye Lijuan Bai Yan Bai Zongjie Gan Hui Zhou Tao Pan Yu Yu Jing Zhou 《Tetrahedron》2019,75(5):682-687
A mild Et3N-catalyzed novel domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenylsubstituted p-QMs and unsaturated isoxazolones is described. Various new spiro-isoxazolonechromans were obtained in good yields (up to 89%) with excellent diastereoselectivities (>99:1 dr). The structure of the new compound 3a was determined by single crystal X-ray analysis. 相似文献
7.
多孔介质结构对渗流惯性效应的影响规律研究 总被引:1,自引:0,他引:1
本文通过局部展开算法研究了多孔介质中排列结构对非线性渗流规律的影响.计算结果表明:规则排列结构的渗流标度律和渗流方向相关,然而非规则排列结构的渗流标度律不依赖于渗流方向而只依赖于多孔介质的几何结构.伴随着排列结构的非规则程度增强,不同方向的渗流阻力变化规律的差异性减小.当流场输运区域较为复杂且不存在较宽直通道时,渗流阻力在较宽雷诺数范围内体现出较为明显的标度律特性.周期性强非规则排列结构中不同区域大小的模型却具有相似的渗流阻力的标度律特性,同时标度律特性与孔隙度的大小相关性不大.阻力非线性标度律由多孔介质结构的不同而取值为2至3之间. 相似文献
8.
A novel and efficient protocol for the synthesis of α,β-unsaturated amides has been developed using catalytic amount of Cu(OAc)2 and TBHP as an available oxidant. Oxidative coupling of various unsaturated carboxylic acids with N,N-disubstituted formamides was examined to furnish the desired products in good yields. 相似文献
9.
K. C. Rajanna N. Maasi Reddy M. Rajender Reddy P. K. Saiprakash 《Journal of Dispersion Science and Technology》2013,34(4):613-616
A Novel Hunsdiecker‐Borodin reaction (HBR) has been carried out efficiently with α,β‐unsaturated aliphatic and aromatic carboxylic acids by using N‐halo succinimides such as N‐chloro succinimide (NCS), N‐bromo succinimide (NBS), and N‐iodo succinimide (NIS) under micellar media. The reaction with α,β‐unsaturated aromatic carboxylic acids afforded β‐halo styrenes in excellent yield while α,β‐unsaturated aliphatic carboxylic acids underwent decarboxylation and to give corresponding halo derivatives. The reactions are dramatically accelerated in micellar media. This procedure works efficiently in CTAB (cetyl trimethyl ammonium bromide), SDS (sodium dodecyl sulfate), and TX (Triton‐X‐100) media under stirred conditions at room temperature. At reflux temperatures the yield of reaction products were further enhanced from good to excellent. 相似文献
10.
XiaoHui Chen 《International Journal of Solids and Structures》2013,50(20-21):3266-3273
This paper has extended modified mixture theory with consideration of hydration swelling in unsaturated rock. By using non-equilibrium thermodynamics and Biot elasticity, a fully coupled formulation including hydration swelling term is derived. Standard arguments of non-equilibrium thermodynamics are used to derive the Darcy’s law for unsaturated flow. Helmholtz free energy has been used to give the relationship between the stress and pore pressure. The chemical potential of water in pore space and clay platelets has been included in the analysis of water sensitive materials such as shale. Finally, a simple numerical example has been presented for illustrative purpose, the results show that the swelling parameter has a strong influence on stress and strain. 相似文献