交联聚合物调驱技术研究及矿场应用

交联聚合物调驱技术是在聚合物驱技术上发展起来的一种集调剖和驱替于一体的化学驱技术。交联聚合物是采用部分水解聚丙烯酰胺与交联剂按一定浓度比形成的凝胶,在油藏中适应性强。与聚合物对比的实验研究表明,交联聚合物调驱技术在黏度、耐温性、耐盐性、热稳定性、剪切恢复性、残余阻力系数等方面具有明显优势。矿场试验结果表明,交联聚合物调驱技术是一种非常有效的提高采收率技术,具有明显的降水增油效果,应推广使用。

高分高黏聚合物驱矿场试验效果评价

高分高黏聚驱达到含水最低点所需的时间比普通聚合物驱长。高分高黏聚驱含水达到最低点的聚合物用量为200～500 mg/L.PV;普通聚合物驱含水达到最低点的聚合物用量为100～400 mg/L.PV。高分高黏聚驱整体的动用程度低于普通浓度聚驱,高分高黏聚驱的动用程度为70%,而普通浓度聚驱的动用程度为85%。高分高黏聚驱的低含水稳定期比普通聚驱长,直接开展高分高黏聚驱区块含水下降幅度大,增油明显。

矿场聚合物溶液粘度影响因素分析

在将聚合物注入到驱油矿场的过程中,很多的因素都会对聚合物溶液的黏度造成影响,比如注入的环境、所投加药剂的性能、混合注入水的水质、注入的流程等。而聚合物溶液黏度的降解也有着很多的方式,比如化学降解、机械降解以及生物降解等的方法。基于这一情况,文章对大庆油田现场所应用的聚合物以及注入过程中的溶液黏度主要影响因素进行研究,并对相应的预防方法进行探讨。

风电场聚合对电力系统安全经济运行的影响

风场内的相关风速对系统的安全经济运行有一定影响。为模拟同一风场内不同位置风速相关性,提出基于多元正态Copula函数及秩相关矩阵度量的方法,量化分析风场内风速相关性。建立风场相关风速样本空间,根据风机出力特性得到风场出力聚合模型。以节能发电调度为原则,对IEEE 30节点和IEEE 300节点系统进行蒙特卡罗最优潮流仿真,结果显示计及风场聚合效应后,风场内部出力的"关联性"及"互补性"得到体现,单位发电成本和支路功率波动范围减小,对节能发电调度策略制定和系统运行方式安排有更明确的指导作用。

影响聚合矿物复合材料线膨胀系数的因素研究

通过正交试验 ,用电感测微仪测试不同配方聚合矿物复合材料的线膨胀系数 ,探讨了材料组分与线膨胀系数之间的关系。

语义场:现代语义学的哥德巴赫猜想

反思语义场理论研究的历史,评价语义场研究的理论与实践,剖析语义场研究中存在的突出问题。

文庙与儒家文化——以昆明地区文庙为例

文庙与儒家文化的关系至为密切。作为儒家文化的聚合场,文庙将文官集团、文化精英、平民阶层以规范化、制度化的方式聚合在一起;作为儒家文化的辐射源,文庙为官方向民众传达国家意志和主流话语提供了平台;作为正统儒学的最高殿堂,文庙传授着正统的儒学,培养了一大批儒家人才。

注聚工艺中低剪切流量控制阀的开发应用

阐述了低剪切流量控制阀在油田三次采油中的应用前景。

密度敏感的数据竞争聚类算法

针对数据竞争聚类算法在处理复杂结构数据集时聚类性能不佳的问题,提出了一种密度敏感的数据竞争聚类算法。首先,在密度敏感距离测度的基础上定义了局部距离,以描述数据分布的局部一致性;其次,在局部距离的基础上计算出数据间的全局距离,用来描述数据分布的全局一致性,挖掘数据的空间分布信息,以弥补欧氏距离描述数据分布全局一致性能力不佳的缺陷;最后,将全局距离用于数据竞争聚类算法中。将新算法与基于欧氏距离的数据竞争聚类算法进行性能比较,在人工数据集和真实数据集上的实验结果表明,该算法克服了数据竞争聚类算法难以处理复杂结构数据的缺点,聚类结果具有更高的准确率。

基于视图相关因子的多视图数据竞争聚类算法

针对现有的单视图数据竞争聚类算法无法高效处理多视图数据的问题,提出了基于视图相关因子的多视图数据竞争聚类算法。首先,为了描述不同视图之间的相关性定义了一种视图相关性因子;然后,将视图相关因子与谱方法关于拉普拉斯矩阵的目标函数最大化问题结合,建立一个联合目标函数,使得不同视图之间的信息相互影响,以充分利用多视图的信息。通过解决联合目标函数的优化问题,得到每个视图的优化嵌入矩阵;最后,将得到的优化嵌入矩阵用于数据竞争聚类算法中。在人工和真实数据集上的仿真实验结果表明,新算法比现有的数据竞争聚类算法具有更高的聚类性能。

密度自适应的数据竞争聚类算法

针对现有数据竞争聚类算法在处理密度不均匀数据集时聚类效果不理想的问题,提出了一种密度自适应的数据竞争聚类算法。首先,定义了一种局部密度自适应线段;然后,根据局部密度自适应线段计算出密度自适应相似度,密度自适应相似度不仅反映了数据的整体空间分布信息,还反映了数据点的局部信息,更加符合数据的实际分布;最后,将密度自适应相似度用于数据竞争聚类算法中。在人工和真实数据集上的仿真实验结果表明,新算法比现有的数据竞争聚类算法在处理密度不均匀数据集时,具有更高的聚类性能。

纳米间隙润滑剂季戊四醇四酯的压缩性能分子动力学模拟

季戊四醇四酯(Pentaerythritol tetra(2-ethylhexanoate),PETE)是良好的环境友好润滑剂。采用聚合物一致性力场(PCFF),分别在2种温度、3种初始油膜厚度和8种压力下对纳米间隙中PETE的压缩性能进行分子动力学模拟,研究润滑剂分子和密度的分布规律,并与经典宏观压缩试验得出的Tait方程计算值进行比较。结果表明,随着初始油膜厚度的增加,分子动力学模拟结果越接近Tait方程计算值,当初始油膜厚度为9.17 nm时,相对误差小于5%。在压缩过程中,油膜厚度和润滑剂的可压缩性能随着压力的增大而减小。对于不同初始油膜厚度的油膜,其压缩性能相近。由于PETE的分子结构中有较多且较长的支链,各方向尺度没有太大差异,受压缩后,除了接近固体壁面处有润滑剂原子聚集,其他地方不存在分层现象,且润滑剂与固体壁面之间不存在明显的空隙。

A Modified Phase-Field Model for Polymer Crystal Growth

The irrationality of existing phase field model is analyzed and a modified phase-field model is proposed for polymer crystal growth, in which the parameters are obtained from real materials and very simple to use, and most importantly, no paradoxical parameters appeared in the model. Moreover, it can simulate different microstructure patterns owing to the use of a new different free energy function for the simulation of morphologies of polymer. The new free energy function considers both the cases of T〈Tm and T≥Tm, which is more reasonable than that in published literatures that all ignored the T≥Tm case. In order to show the validity of the modified model, the finite difference method is used to solve the model and different crystallization morphologies during the solidification process of isotactic polystyrene are obtained under different conditions. Numerical results show that the growth rate of the initial secondary arms is obviously increased as the anisotropy strength increases. But the anisotropy strength seems to have no apparent effect on the global growth rate. The whole growth process of the dendrite depends mainly upon the latent heat and the latent heat has a direct effect on the tip radius and tip velocity of side branches.

Effect of magnetic field on property and structure of polyaniline doped with multiple sulfonic acids

Polyaniline(PAn)doped with multiple sulfonic acid system of dodecylbenzenesulfonic acid(DBSA)and sulfosalicylic acid(SSA)was synthesized by emulsion polymerization using ammonium persulfate(APS)as an oxidizing agent in the presence and the absence of a constant magnetic field(MF)of 0.8 T.The structure and properties of the PAn were characterized by X-ray diffractometer(XRD),thermogravimetric apparatus(TGA),FT-IR spectroscope(FT-IR)and four probe digital multimeter.The results indicate that,when the molar ratio of DBSA to SSA is 1/3,that of dopant to An is 3/2,that of APS to An is 4/5 in the synthesizing media,and the doping time is 3 h,the conductivity of the PAn synthesized in the presence of the MF of 0.8 T reaches 5.88 S/cm,which is higher than that of the PAn synthesized in the absence of the MF.The thermal stability,the crystallinity and the doping degree of the PAn synthesized in the presence of the MF are also improved.MF not only enhances the conductivity,but also reduces the doping time,the dosage of the dopant and the oxidizing agent when the conductivity reaches the maximum.

Collapse of Four-Arm Stars Polyelectrolyte Brushes Under An Electric Field in the Presence of Trivalent Salt Coions

Langevin dynamics simulations were conducted to study the collapse of grafted partially charged 4-arm star chains onto the oppositely charged grafting electrode in the presence of trivalent salt coions.Simulation results reveal that the average charge fraction of the grafted star chains and the salt concentration play critical roles in the competitive adsorption of charged monomers and trivalent salt coions onto the oppositely charged electrode.For grafted star chains with relatively high charge fraction,charged monomers are the dominant species collapsing on the oppositely charged electrode with the emergence of charge reversal on the grafting electrode.At a low charge fraction such that the total amount of charges on a grafted star molecule is comparable to that of a trivalent salt coion,trivalent salt coions absorb more strongly onto the electrode than grafted stars even at very low salt concentration.It is found that at relatively low charge fraction of star chains,the addition of trivalent salt coions does not lead to charge overcompensation of the surface charges on the grafting electrode.The stretching of star brushes under an electric field in the presence of trivalent salt coions was also briefly investigated.

Nonlinear Optical Response of Conjugated Polymer to Elec tric Field

The organic π-conjugate d polymers are of major interest materials for the use in electro-optical and no nlinear optical devices. In this work, for a selected polyacetylene chain, the optical absorption spectra in UV/Vis regime as well as the linear polarizabiliti y and nonlinear hyperpolarizability are calculated by using quantum chemical ab initio and semiempirical methods. The relationship of its optical property to el ectric field is obtained. Some physical mechanism of electric field effect on mo lecular optical property is discussed by means of electron distribution and intr amolecular charge transfer.

Multiple Antimicrobial Resistance of Extended Spectrum Beta-Lactamase-Producing Escherichia coli from Small-Scaled Poultry Farms and Retail Chicken

Antibiotics used for agricultural purpose has contributed to the increased prevalence of antibiotic-resistant bacteria. The goal of this study was to investigate the prevalence and antimicrobial resistance of ESBL-producing E. coli in small-scaled poultry farms and retail chicken. The cultured E. coli isolates were subjected to phenotypic tests, susceptibility tests, and the polymerase chain reaction for detection of blacTX-M, blasHv, and blaTEM genes. From 120 samples each of chicken feces, retail chicken, soil and chicken feed, ESBL-producing E. coli isolates were detected in 75.9%, 63.6%, 39.2%, and 13.3% of the samples, respectively. Minimum inhibitory concentration （MICs） values indicated that ESBL-producing E. coli were resistance to ampicillin （MIC 〉 32 μg/mL）, gentamicin （M1C ≥ 16 μg/mL）, cefotaxime （MIC 〉 4 μg/mL） and cefhiaxone （MIC 〉 4 gg/mL）, respectively. The total resistance for imipenem was also observed at 1.0% （MIC ≥ 4 gg/mL） and none of the isolates were resistant to ceftazidime （MIC 〉 16 μg/mL）. ESBL-producing E. coli from chicken feces and retail chicken carried blasHv gene at a rate of 6.8% and 5.7%, respectively and blaCTX-M gene was also revealed at 2.9% in retail chicken. Moreover, ESBL-producing E. coli isolated from soil harbored blasnv and blaCTX-M genes at 5%. None of the feed samples yielded ESBLs genes. Twenty three resistance patterns were observed for multi-resistant ESBL-producing E. coli. This study highlights the prevalence of multi-antimicrobial resistant ESBL-producing E. coli in small-scaledpoultry farms and retail chicken, hence the need to review poultry management practices to minimize the occurrence.

Performance of Square Lightweight Concrete Specimens Confined by CFRP and GFRP

Confinement is an effective method in order to increase concrete strength and its ductility capacity. To improve the structural properties of lightweight concrete, Fiber Reinforced Polymer （FRP） can be used to confine the concrete. Effect of Fiber Reinforced Polymer on confined lightweight concrete elements is one of the most important research fields. It is generally accepted that the strength and stiffness of confined concrete is higher than unconfined one. In this research, behavior of confined and unconfined concrete specimens under uniaxial loading has been studied. In order to decrease stress concentration corners of specimens were chamfered to a radius of 5 to 25 mm. The Carbon Fiber Reinforced Polymer （CFRP） and Glass Fiber Reinforced Polymer （GFRP） were used to confine lightweight concrete specimens. The stress-strain curve of specimens is compared.

Present Situation and Development of Chinese Grain Food Safety

The recent outstanding issues,＂ puzzles of farmers, anxiety oflocal government and helplessness ofcentral government,＂ facing Chinese grain security, depend on the lack of national food security strategy. Therefore, we must reconstruct our national food security strategy with a cornerstone of an integrated productivity, the focus control of market regulation forces and the protection of sovereignty. By analyzing the status of integrated productivity, market regulation force and sovereign control, this essay proposes that we should change the concept from ＂ food production＂ to ＂foOd management＂, design the two systems of the interest coordination and the special safeguard, effectively improve the enthusiasm of the government＇ s undertaking work in grain-producing areas and farmers＇ farming work, firmly grasp the two initiatives of acquisition and processing of grain and operating inputs, and actively apply recommendations of the two regulators： food exports, processing and conversion.