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The construction of pseudo-Janus silica/surfactant assembly and their application to stabilize Pickering emulsions and enhance oil recovery

《化学科学与工程前沿（英文）》 2022年第16卷第7期页码 1101-1113 doi: 10.1007/s11705-021-2095-1

摘要： Nanoparticles with high surface energy and chemical activity have drawn substantial attention in petroleum industry. Recently, Janus nanoparticles exhibited tremendous potential in enhanced oil recovery (EOR) due to their asymmetric structures and properties. In this study, a series of amphiphilic pseudo-Janus@OTAB (PJ@C18) nanoparticles with different concentrations of stearyltrimethylammoium bromide (OTAB) were successfully fabricated. The structures and properties of PJ@C18 were characterized by Fourier transform infrared spectroscopy and ζ-potential measurements. Based on the emulsification experimental results, the interaction models and the self-assembly behavior between hydrophilic nanoparticles (SiO₂@NH₂) and OTAB molecules at the oil/water interface were proposed, which was further confirmed via the measurements of the contact angle and dynamic interfacial tension. Interestingly, it was found that the change of pH value from 7.5 to 4.0 caused the type reversal of the PJ@C18-1000 stabilized Pickering emulsions. Furthermore, the PJ@C18-1000 stabilized Pickering emulsion system with excellent salt and temperature tolerances (10000 mg∙L^–1, 90 °C) significantly improved the oil recovery in the single-tube (more than 17%) and double-tube (more than 25%) sand pack model flooding tests. The findings of this study could help to better understand the construction mechanism of pseudo-Janus silica/surfactant assembly and the potential application of PJ@C18-1000 stabilized Pickering emulsions for EOR.

关键词： Janus nanoparticles surfactant double phase inversion self-assembly enhanced oil recovery

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Kinematical synthesis of an inversion of the double linked fourbar for morphing wing applications

J. AGUIRREBEITIA, R. AVILéS, I. FERNáNDEZ, M. ABASOLO

《机械工程前沿（英文）》 2013年第8卷第1期页码 17-32 doi: 10.1007/s11465-013-0364-5

摘要：

This paper presents the kinematical features of an inversion of the double linked fourbar for morphing wing purposes. The structure of the mechanism is obtained using structural synthesis concepts, from an initial conceptual schematic. Then, kinematic characteristics as instant center of rotation, lock positions, dead point positions and uncertainty positions are derived for this mechanism in order to face the last step, the dimensional synthesis; in this sense, two kinds of dimensional synthesis are arranged to guide the wing along two positions, and to fulfill with the second one some aerodynamic and minimum actuation energy related issues.

关键词： morphing wing structural synthesis dimensional synthesis geometrical kinematics

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NIPS法聚偏氟乙烯超滤膜的制备与应用

吕晓龙,武春瑞,张昊,赵丽华

《中国工程科学》 2014年第16卷第12期页码 35-45

摘要：

非溶剂相分离（NIPS）制膜方法是20世纪60年代发明的一种高效的制膜方法。利用该法制备的不对称膜结构赋予膜优异的选择渗透性能，膜孔结构易于调控，已经成为当前聚合物分离膜研究及商业化生产中普遍采用的方法。聚偏氟乙烯（PVDF）具有优异的综合性能，成膜性能佳，可利用NIPS法制膜。NIPS法PVDF膜的研制、膜结构控制方法及应用研究受到国际膜研究者广泛关注，是分离膜领域热点之一。本文分别针对NIPS法PVDF超滤膜制备的相分离原理研究、膜结构控制方法及膜应用研究等关键研究进展作简要介绍。

关键词：非溶剂致相分离聚偏氟乙烯超滤膜相分离原理膜结构与性能膜应用

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Solvent-resistant porous membranes using poly(ether−ether ketone): preparation and application

《化学科学与工程前沿（英文）》 2023年第17卷第10期页码 1536-1559 doi: 10.1007/s11705-022-2221-8

摘要： Poly(ether−ether ketone) (PEEK) is a linear aromatic macromolecule, which can form semi-crystalline aggregative status, allowing PEEK materials to have strong environment tolerance and excellent physicochemical properties. PEEK materials have become a promising alternative to fabricate particular membranes used in extreme conditions. In the past few decades, many researches and evolutions have emerged in membrane fabrication with PEEK materials and its applications for treating organic solvents and their mixtures; however, there are little systematic and comprehensive literature to summarize fabrication approaches, compile applications, and elaborate PEEK property-structure relationship. In this review, the main approaches to fabricate PEEK-based membranes are illustrated concretely, including conventional thermal-induced and non-solvent-induced phase separation, and novel chemical-induced crystallization; the representative applications in ultrafiltration, nanofiltration and membrane contactor containing organic solvents are demonstrated systematically. Meanwhile, the mechanism to tune PEEK solubility in solvents, which can be achieved by altering monomers in synthesis processes or changing membrane preparation routes, is deeply analyzed. Moreover, the existing problems and the future prospects are also discussed. This review provides positive guidance for designing and fabricating membranes using PEEK and its derivative materials for task-specific applications in harsh conditions.

关键词： PEEK phase inversion solvent-resistant membrane nanofiltration membrane contactor

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Polysulfone and zirconia composite separators for alkaline water electrolysis

Li XU, Wei LI, Yan YOU, Shaoxing ZHANG, Yingchun ZHAO

《化学科学与工程前沿（英文）》 2013年第7卷第2期页码 154-161 doi: 10.1007/s11705-013-1331-8

摘要： The novel composite separators composed of polysulfone and zirconia were prepared by phase inversion precipitation technique. This technique allows pre-evaporation time and extraction temperature to be varied in order to obtain optimal performances of the separators. In order to evaluate practical applicability of those composite separators, a small-scale electrolysis experimental apparatus was used to investigate the changes of cell voltage, gas purity and separator stability. The results revealed a decreased cell voltage compared to the conventional asbestos separators, and the gas purity and separator stability met the requirements for industrial use.

关键词： phase inversion separator alkaline water electrolysis mechanical and chemical stability

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Two-phase early prediction method for remaining useful life of lithium-ion batteries based on a neural

《能源前沿（英文）》 doi: 10.1007/s11708-023-0906-4

摘要： Lithium-ion batteries (LIBs) are widely used in transportation, energy storage, and other fields. The prediction of the remaining useful life (RUL) of lithium batteries not only provides a reference for health management but also serves as a basis for assessing the residual value of the battery. In order to improve the prediction accuracy of the RUL of LIBs, a two-phase RUL early prediction method combining neural network and Gaussian process regression (GPR) is proposed. In the initial phase, the features related to the capacity degradation of LIBs are utilized to train the neural network model, which is used to predict the initial cycle lifetime of 124 LIBs. The Pearson coefficient’s two most significant characteristic factors and the predicted normalized lifetime form a 3D space. The Euclidean distance between the test dataset and each cell in the training dataset and validation dataset is calculated, and the shortest distance is considered to have a similar degradation pattern, which is used to determine the initial Dual Exponential Model (DEM). In the second phase, GPR uses the DEM as the initial parameter to predict each test set’s early RUL (ERUL). By testing four batteries under different working conditions, the RMSE of all capacity estimation is less than 1.2%, and the accuracy percentage (AP) of remaining life prediction is more than 98%. Experiments show that the method does not need human intervention and has high prediction accuracy.

关键词： lithium-ion batteries RUL prediction double exponential model neural network Gaussian process regression (GPR)

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基于双正交复序列的高效扩频调制方法

史小红

《中国工程科学》 2012年第14卷第3期页码 108-112

摘要：

提出了一种采用双正交复序列的高效扩频调制与解调方法（DoCS）。输入数据比特流被分割为长度为M的组，每组的M比特作为输入码字，从2M-2个长度为L的DoCS序列中选择一条序列进行发送，被选中的序列以QPSK方式调制在载波上，实现扩频通信。文中还提出了一种前向相位校正(FPC)方法来解决该系统中收发两端的载波同步问题。

关键词：调制与解调技术高效扩频调制前向相位校正双正交码

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均质纤维素膜的制备及其正渗透性能研究

张兵涛,张林,黄和,侯立安

《中国工程科学》 2014年第16卷第7期页码 57-61

摘要：

以纤维素（cellulose）为膜材料，离子液体1-乙基-3 甲基咪唑醋酸盐（EMIMAc）为溶剂，水为非溶剂，无纺布作为支撑层，通过相转化法制备了纤维素均质膜。采用红外、X-射线衍射和扫描电子显微镜表征了膜的结构及形貌，考察了该膜的正渗透性能。结果表明：纤维素溶解再生过程中没有发生化学变化，但晶型发生了转变；当原料液为0.6 mol/L 的氯化钠水溶液，汲取液为特制的营养液时，所制备的正渗透膜的水通量为3.534 L/（m²· h），截盐率达到99 %以上。

关键词：正渗透离子液体纤维素膜相转化膜制备

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智能高分子开关膜的制备方法研究进展

谢锐,刘壮,巨晓洁,汪伟,褚良银

《中国工程科学》 2014年第16卷第12期页码 94-101

摘要：

智能高分子开关膜是将智能高分子与非刺激响应型基材膜结合而成。由于智能高分子能够响应外界刺激发生亲疏水性转变和构象变化，智能高分子开关膜也能根据外部刺激改变自身的表面/界面特性、渗透通量或选择透过性。智能高分子膜被用作抗污染滤膜、亲和分离、酶反应的起/停控制以及控制释放等。智能高分子开关膜的制备方法直接影响其环境刺激响应特性、稳定性和可重复制备性等。因此，系统介绍了基材膜修饰法、基材修饰成膜法和共混成膜法等3种智能高分子开关膜制备方法的定义、分类、机理和研究进展，并对比了3种方法的优缺点。基材膜修饰法研究最多，而共混成膜法最有望用于大规模制备智能高分子膜。本文以期为高效制备具有稳定、优良响应特性的智能高分子开关膜提供指导和参考。

关键词：智能高分子膜智能凝胶智能线性高分子制备方法相转化法

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Experimental measurement of double-K fracture parameters of concrete with small-size aggregates

ZHANG Xiufang, XU Shilang, ZHENG Shuang

《结构与土木工程前沿（英文）》 2007年第1卷第4期页码 448-457 doi: 10.1007/s11709-007-0061-8

摘要： The double- fracture model can well describe the development of cracks undergoing during the entire fracture process in concrete. Therefore, it has been selected as the theoretical basis of the Norm for fracture test of

关键词： development concrete theoretical double- fracture

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交直流电力集成技术

马伟明

《中国工程科学》 2002年第4卷第12期页码 53-59

摘要：

建立了新型电机的数学模型，为解决关键技术问题提供了理论基础。查明了发电机整流系统特有的低频功率振荡的机理，得出了稳定判据及解决稳定问题的技术措施；通过合理设计，可控制直流电压的浮动范围；综合治理整流过程引起的交流谐波和直流脉动，提高了系统的EMC性能；巧妙地处理了系统的强非线性，从而得出了直流短路和交直流同时短路的冲击电流解析式；提出了根据整流装置输入、输出电压波形进行实时在线故障诊断的原理和方法。在此基础上，将定子3相绕组、12相绕组、整流装置、励磁系统、励磁调节器等集于一体，功研制出性能优良的交直流发电机，能同时提供高品质交直流电源，为独立电力系统的集成化奠定了基础。

关键词：电力集成双绕组交直流发电机 12相整流交直流同时供电独立电力系统

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Numerical study of thermal characteristics of double skin facade system with middle shade

Shaoning LIU, Xiangfei KONG, Hua YANG, Minchao FAN, Xin ZHAN

《能源前沿（英文）》 2021年第15卷第1期页码 222-234 doi: 10.1007/s11708-017-0480-8

摘要： Architectural shade is an effective method for improving building energy efficiency. A new shade combined with the double skin façade (DSF) system, called middle shade (MS), was introduced and developed for buildings. In this paper, a 3D dynamic simulation was conducted to analyze the influence of MS combined with DSF on the indoor thermal characteristics. The research on MS for DSF involves the temperature, the ventilation rate, the velocity distribution of the air flow duct, and the indoor temperature. The results show that the angle and position of the shade in the three seasons are different, and different conditions effectively enhance the indoor thermal characteristics. In summer, the appearance of MS in DSF makes the indoor temperature significantly lower. The indoor temperature is obviously lower than that of the air flow duct, and the temperature of the air flow duct is less affected by MS. The influence of the position of blinds on indoor temperature and ventilation rate is greater than the influence of the angle of blinds. According to the climate characteristics of winter and transition season, in winter, early spring, and late autumn, the indoor temperature decreases with the increase of the position of blinds at daytime, but the opposite is true at night. The results found in this paper can provide reference for the design and use of MS combined with DSF in hot summer and cold winter zone.

关键词： middle shade position thermal characteristics double skin facade

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Moment-curvature relationship of FRP-concrete-steel double-skin tubular members

Mingxue LIU, Jiaru QIAN

《结构与土木工程前沿（英文）》 2009年第3卷第1期页码 25-31 doi: 10.1007/s11709-009-0012-7

摘要： Tests were conducted on 3 specimens to study the flexural behavior of fiber reinforced polymer (FRP)-concrete-steel double-skin tubular members (DSTMs). The strip method was used to calculate the section moment-curvature curves of the 3 specimens and 12 models. A theoretical formula is presented for the flexural strength of DSTMs. The test results show that the tension zone of the specimen FRP tubes was in hoop compression while the compression zone was in hoop tension. The load-carrying capacity did not decrease even when the mid-span deflection reached about 1/24 of the span length. The tests, simulation and theoretical analysis resulted in a simplified formula for the flexural strength of DSTMs and a tri-linear moment-curvature model was expressed as a function of the section bending stiffness for DSTMs.

关键词： fiber reinforced polymer (FRP) concrete steel double-skin tubular members (DSTMs) moment-curvature curve flexural strength

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Enhancement of distillate output of double basin solar still with vacuum tubes

Hitesh N PANCHAL, P K SHAH

《能源前沿（英文）》 2014年第8卷第1期页码 101-109 doi: 10.1007/s11708-014-0299-5

摘要： The latent heat of condensation is lost to the atmosphere; hence it is not utilized to increase distillate output of single basin solar stills. This difficulty was overcome by attaching an additional basin to the main basin. The performance of the double basin solar still was also increased by attaching vacuum tubes to the lower basin; hence the lower basin possessed a higher temperature throughout the day. The latent heat of condensation of the bottom basin was also utilized to increase distillate. But the distillate output of the top basin was even lower compared with that of the bottom basin. This paper proposed a novel approach to increase the distillate output of the double basin solar still attached with vacuum tubes by introducing different sensible energy storage materials like pebbles, black granite gravel and calcium stones to increase the basin area. Experiments were conducted in climate conditions of Mehsana (23.6000° N, 72.4000° E) Gujarat from April to September 2013 with a constant water depth of 2 cm in the top basin with and without the use of basin materials. The results showed that the distillate output of basin material with calcium stones is greater (74%) compared with that of black granite gravel and pebbles. The integration of vacuum tubes with solar still greatly increases the distillate output of the solar still by providing hot water at the lower basin.

关键词： double basin solar still calcium stones pebbles granite gravel distillate output

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Meshless numerical method based on tensor product

SUN Haitao, WANG Yuanhan, MIAO Yu

《结构与土木工程前沿（英文）》 2008年第2卷第2期页码 166-171 doi: 10.1007/s11709-008-0021-y

摘要： A normalized space constructed by tensor product is used in field function approach to give a special case of moving least squares (MLS) interpolation scheme. In the regular domain, the field function which meets homogenous boundary conditions is constructed by spanning base space to make the MLS interpolation scheme simpler and more efficient. Owing to expanded basis functions selection, some drawbacks in general MLS method, for example repeated inversion, low calculation efficiency, and complex criterions, can be avoided completely. Numerical examples illustrate that the proposed method is characterized by simple mathematical concept, convenient repeat calculations with high accuracy, good continuity, less computation and rapid convergence.

关键词： mathematical continuity inversion selection efficient