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Bicontinuous porous membranes with micro-nano composite structure using a facile atomization-assistednonsolvent induced phase separation method

《化学科学与工程前沿（英文）》 2022年 第16卷 第8期   页码 1268-1280 doi: 10.1007/s11705-022-2143-5

摘要： The micro-nano composite structure can endow separation membranes with special surface properties, but it often has the problems of inefficient preparation process and poor structural stability. In this work, a novel atomization-assisted nonsolvent induced phase separation method, which is also highly efficient and very simple, has been developed. By using this method, a bicontinuous porous microfiltration membrane with robust micro-nano composite structure was obtained via commercially available polymers of polyacrylonitrile and polyvinylpyrrolidone. The formation mechanism of the micro-nano composite structure was proposed. The microphase separation of polyacrylonitrile and polyvinylpyrrolidone components during the atomization pretreatment process and the hydrogen bonding between polyacrylonitrile and polyvinylpyrrolidone molecules should have resulted in the nano-protrusions on the membrane skeleton. The membrane exhibits superhydrophilicity in air and superoleophobicity underwater. The membrane can separate both surfactant-free and surfactant-stabilized oil-in-water emulsions with high separation efficiency and permeation flux. With excellent antifouling property and robust microstructure, the membrane can easily be recycled for long-term separation. Furthermore, the scale-up verification from laboratory preparation to continuous production has been achieved. The simple, efficient, cost-effective preparation method and excellent membrane properties indicate the great potential of the developed membranes in practical applications.

关键词： atomization     nonsolvent induced phase separation     bicontinuous porous structure     micro-nano composite structure     oil-water separation    

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Tuning of the active phase structure and hydrofining performance of alumina-supported tri-metallic WMoNi

Shufeng Shan, Haiyan Liu, Gang Shi, Xiaojun Bao

《化学科学与工程前沿（英文）》 2018年 第12卷 第1期   页码 59-69 doi: 10.1007/s11705-017-1686-3

摘要： The effects of phosphorus on the structure and hydrofining performance of tri-metallic WMoNi/Al O catalysts prepared with W/Mo-based hybrid precursor nanocrystals were investigated. The incorporation of phosphorus weakened the metal-support interactions (MSIs) and facilitated the formation of more synergetic NiWMoS phases with higher stacks. Catalytic tests using a fluid catalytic cracking diesel fuel showed that the changes in the MSIs and the morphology of the active phases had a more positive effect on the hydrodenitrogenation activity than on the hydrodesulfurization activity. In contrast, when phosphorus was incorporated into a tri-metallic WMoNiP/Al O catalyst prepared by a conventional incipient impregnation method, the MSIs decreased causing aggregation of the metal species which resulted in poorer hydrofining performance of the catalyst. These results show that incorporating phosphorus into a WMoNi/Al O catalyst can finely tune the structure of the active phase to enhance the hydrogenation and hydrodenitrogenation activity of the resulting tri-metallic catalyst.

关键词： fluid catalytic cracking diesel     hydrofining performance     WMoNiP/Al2O3     synergetic effect and structure of NiWMoS phases    

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computational toolbox for molecular property prediction based on quantum mechanics and quantitative structure-property

《化学科学与工程前沿（英文）》 2022年 第16卷 第2期   页码 152-167 doi: 10.1007/s11705-021-2060-z

摘要： Chemical industry is always seeking opportunities to efficiently and economically convert raw materials to commodity chemicals and higher value-added chemical-based products. The life cycles of chemical products involve the procedures of conceptual product designs, experimental investigations, sustainable manufactures through appropriate chemical processes and waste disposals. During these periods, one of the most important keys is the molecular property prediction models associating molecular structures with product properties. In this paper, a framework combining quantum mechanics and quantitative structure-property relationship is established for fast molecular property predictions, such as activity coefficient, and so forth. The workflow of framework consists of three steps. In the first step, a database is created for collections of basic molecular information; in the second step, quantum mechanics-based calculations are performed to predict quantum mechanics-based/derived molecular properties (pseudo experimental data), which are stored in a database and further provided for the developments of quantitative structure-property relationship methods for fast predictions of properties in the third step. The whole framework has been carried out within a molecular property prediction toolbox. Two case studies highlighting different aspects of the toolbox involving the predictions of heats of reaction and solid-liquid phase equilibriums are presented.

关键词： molecular property     quantum mechanics     quantitative structure-property relationship     heat of reaction     solid-liquid phase equilibrium    

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Mesoscopic properties of dense granular materials: An overview

Qicheng SUN, Feng JIN, Guohua ZHANG

《结构与土木工程前沿（英文）》 2013年 第7卷 第1期   页码 1-12 doi: 10.1007/s11709-013-0184-z

摘要： A granular material is a conglomeration of discrete solid particles. It is intrinsically athermal because its dynamics always occur far from equilibrium. In highly excited gaseous states, it can safely be assumed that only binary interactions occur and a number of kinetic theories have been successfully applied. However, for granular flows and solid-like states, the theory is still poorly understood because of the internally correlated structures, such as particle clusters and force networks. The current theory is that the mesoscale characteristics define the key differences between granular materials and homogeneous solid materials. Widespread interest in granular materials has arisen among physicists, and significant progress has been made, especially in understanding the jamming phase diagram and the characteristics of the jammed phase. In this paper, the underlying physics of the mesoscale structure is discussed in detail. A multiscale framework is then proposed for dense granular materials.

关键词： granular matter     macroscopic structure     jamming phase transition    

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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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DyFe11Ti磁结构及其自旋重取向的中子衍射研究 Article

Olivier Isnard, Eder J. Kinast

《工程（英文）》 2020年 第6卷 第2期   页码 153-157 doi: 10.1016/j.eng.2019.11.009

摘要：

本文报道了通过中子粉末衍射探测DyFe11Ti的磁结构及其热演化规律。使用了变温中子衍射技术来测量磁矩及其取向的温度依赖性。Dy和Fe磁矩以反向平行的方式形成亚铁磁性耦合，其2 K时的易磁化方向是基面(a, b)内的[110]轴。随着温度的升高，该磁结构先后经历了两次自旋重取向现象。低温下，Dy磁矩较大，达到9.7μB，而在200 K时磁矩迅速下降到7.5μB。在Fe 8i位置观察到了最大的Fe磁矩。尽管磁结构发生了很大的变化，但在研究的温度范围内ThMn12型晶体结构一直保持不变。在第一阶段的自旋重取向温度（TSR1）时，观察到了易磁化轴的急剧倾斜；易磁化轴与晶体c轴之间的夹角从2 K的90°减小到200 K时的约20°（其中c轴是200 K以上的易磁化轴）；同时Dy和Fe磁矩保持反向平行耦合。

关键词： 中子衍射，磁相图，晶体结构    

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Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and hydrophilic drugs

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

《化学科学与工程前沿（英文）》 2014年 第8卷 第4期   页码 498-510 doi: 10.1007/s11705-014-1451-9

摘要： Design of biocompatible and biodegradable polymer systems for sustained and controlled release of bioactive agents is critical for numerous biomedical applications. Here, we designed, synthesized, and characterized four polyurethane carrier systems for controlled release of model drugs. These polyurethanes are biocompatible and biodegradable because they consist of biocompatible poly(ethylene glycol) or poly(caprolactone diol) as soft segment, linear aliphatic hexamethylene diisocyanate or symmetrical aliphatic cyclic dicyclohexylmethane-4,4′-diisocyanate as hard segment, and biodegradable urethane linkage. They were characterized with Fourier transform infrared spectroscopy, atomic force microscope, and differential scanning calorimetry, whereas their degradation behaviors were investigated in both phosphate buffered saline and enzymatic solutions. By tuning polyurethane segments, different release profiles of hydrophobic and hydrophilic drugs were obtained in the absence and presence of enzymes. Such difference in release profiles was attributed to a complex interplay among structure, hydrophobicity, and degradability of polyurethanes, the size and hydrophobicity of drugs, and drug-polymer interactions. Different drug-polyurethane combinations modulated the distribution and location of the drugs in polymer matrix, thus inducing different drug release mechanisms. Our results highlight an important role of segmental structure of the polyurethane as an engineering tool to control drug release.

关键词： phase structure     degradation     polyurethanes     controlled release     drug delivery    

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非规则时序信息的结构转换及演化的细化分析

欧阳首承,张葵,郝丽萍,周莉蓉

《中国工程科学》 2005年 第7卷 第4期   页码 36-41

摘要：

按时间不占有物质维的概念，将时序性自动信息转换为结构信息。结果显示自动信息的非规则可用于降水的细化预测，也为更广泛的演化非规则信息提供了可应用的方法，充分地说明了气象问题是演化科学的问题，或者说将其理解为牛顿的惯性系领域的分支科学是有待商榷的。

关键词： 时序信息     细化     结构非规则     方位相空间     演化    

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Microfluidic production of liposomes through liquid–liquid phase separation in ternary droplets

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 1017-1022 doi: 10.1007/s11705-021-2118-y

摘要： Liposomes, the self-assembled phospholipid vesicles, have been extensively used in various fields such as artificial cells, drug delivery systems, biosensors and cosmetics. However, current microfluidic routes to liposomes mostly rely on water-in-oil-in-water double emulsion droplets as templates, and require complex fabrication of microfluidic devices, and tedious manipulation of multiphase fluids. Here we present a simple microfluidic approach to preparing monodisperse liposomes from oil-in-water droplets. For demonstration, we used butyl acetate-water-ethanol ternary mixtures as inner phase and an aqueous solution of surfactants as outer phase to make oil-in-water droplets, which can evolve into water-in-oil-in-water double emulsion droplets by liquid–liquid phase separation of ternary mixtures. Subsequently, the resultant water-in-oil-in-water droplets underwent a dewetting transition to form separated monodisperse liposomes and residual oil droplets, with the assistance of surfactants. The method is simple, does not require complex microfluidic devices and tedious manipulation, and provides a new platform for controllable preparation of liposomes.

关键词： microfluidics     liposomes     ternary droplets     phase separation    

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Advances and perspectives in catalysts for liquid-phase oxidation of cyclohexane

Hui LI, Yuanbin SHE, Tao WANG

《化学科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 356-368 doi: 10.1007/s11705-012-0903-3

摘要： The latest progress and developments in catalysts for the oxidation of cyclohexane are reviewed. Catalytic systems for the oxidation of cyclohexane including metal supported, metal oxides, molecular sieves, metal substituted polyoxometalates, photocatalysts, organocatalysts, Gif systems, metal-organic catalysts and metalloporphyrins are discussed with a particular emphasis on metalloporphyrin catalytic systems. The advantages and disadvantages of these methods are summarized and analyzed. Finally, the development trends in the oxidation technology of cyclohexane are examined.

关键词： cyclohexane     liquid-phase oxidation     catalysis    

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Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 114-120 doi: 10.1007/s11709-014-0267-5

摘要： The accurate and efficient simulation of random heterogeneous media is important in the framework of modeling and design of complex materials across multiple length scales. It is usually assumed that the morphology of a random microstructure can be described as a non-Gaussian random field that is completely defined by its multivariate distribution. A particular kind of non-Gaussian random fields with great practical importance is that of translation fields resulting from a simple memory-less transformation of an underlying Gaussian field with known second-order statistics. This paper provides a critical examination of existing random field models of heterogeneous two-phase media with emphasis on level-cut random fields which are a special case of translation fields. The case of random level sets, often used to represent the geometry of physical systems, is also examined. Two numerical examples are provided to illustrate the basic features of the different approaches.

关键词： microstructure     random fields     level sets     shape recovery     two-phase media    

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Phase transition regulation and caloric effect

《能源前沿（英文）》 2023年 第17卷 第4期   页码 463-477 doi: 10.1007/s11708-023-0860-1

摘要： Solid state refrigeration based on caloric effect is regarded as a potential candidate for replacing vapor-compression refrigeration. Numerous methods have been proposed to optimize the refrigeration properties of caloric materials, of which single field tuning as a relatively simple way has been systemically studied. However, single field tuning with few tunable parameters usually obtains an excellent performance in one specific aspect at the cost of worsening the performance in other aspects, like attaining a large caloric effect with narrowing the transition temperature range and introducing hysteresis. Because of the shortcomings of the caloric effect driven by a single field, multifield tuning on multicaloric materials that have a coupling between different ferro-orders came into view. This review mainly focuses on recent studies that apply this method to improve the cooling performance of materials, consisting of enlarging caloric effects, reducing hysteresis losses, adjusting transition temperatures, and widening transition temperature spans, which indicate that further progress can be made in the application of this method. Furthermore, research on the sign of lattice and spin contributions to the magnetocaloric effect found new phonon evolution mechanisms, calling for more attention on multicaloric effects. Other progress including improving cyclability of FeRh alloys by introducing second phases and realizing a large reversible barocaloric effect by hybridizing carbon chains and inorganic groups is described in brief.

关键词： phase transition regulation     caloric effect     solid state refrigeration    

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Effect of graphene and its derivatives on thermo-mechanical properties of phase change materials and

《能源前沿（英文）》 2022年 第16卷 第2期   页码 150-186 doi: 10.1007/s11708-021-0795-3

摘要： Phase change materials (PCMs) play a leading role in overcoming the growing need of advanced thermal management for the storage and release of thermal energy which is to be used for different solar applications. However, the effectiveness of PCMs is greatly affected by their poor thermal conductivity. Therefore, in the present review the progress made in deploying the graphene (Gr) in PCMs in the last decade for providing the solution to the aforementioned inadequacy is presented and discussed in detail. Gr and its derivatives ((Gr oxide (GO), Gr aerogel (GA) and Gr nanoplatelets (GNPs)) based PCMs can improve the thermal conductivity and shape stability, which may be attributed to the extra ordinary thermo-physical properties of Gr. Moreover, it is expected from this review that the advantages and disadvantages of using Gr nanoparticles provide a deep insight and help the researchers in finding out the exact basic properties and finally the applications of Gr can be enhanced.

关键词： phase change materials (PCMs)     graphene     thermal conductivity     characterization    

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Distributed energy management for networked microgrids in a three-phase unbalanced distribution network

《能源前沿（英文）》 2023年 第17卷 第3期   页码 446-446 doi: 10.1007/s11708-022-0851-7

摘要： Owing to increased penetration of three-phase and single-phase microgrids, distributed energy resources (DERs), and responsive loads, the maintenance of a three-phase balance by distribution networks is a significant challenge. Existing literature on distributed energy management for networked microgrids generally neglects the distribution network or employs a simplified phase balanced distribution network; thus, these evaluations are not applicable. Further, the underlying mutual coupling between the different phases of distribution feeders results in a more challenging situation. To solve this issue, this study sought to propose distributed energy management based on a three-phase unbalanced distribution network. Various three-phase or single-phase microgrids, utility-owned DERs, and responsive loads were coordinated through iteratively adjusted price signals. Based on the price signals received, the microgrid controllers (MCs) and distribution management system (DMS) updated the schedules of the DERs and responsive loads under their jurisdiction separately. The price signals were then updated according to the generation-load mismatch at each node and distributed to the corresponding MCs and DMS for the next iteration. The iteration continued until a sufficiently small generation-load mismatch was achieved at all nodes, that is, a balanced generation and load at all nodes under the agreed price signals. Considering a three-phase unbalanced distribution network, the price signals were determined per phase per node. Overall, the proposed distributed energy management coordinates microgrids, utility-owned DERs, responsive loads with guaranteed network constraints, and preserves the privacy of microgrid customers. This distributed energy management method was further demonstrated through various case studies on a three-phase networked microgrid test system.

关键词： distributed optimization     energy management     networked microgrids     three-phase distribution network     distributed energy resources    

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Analysis of the radiation heat transfer process of phase change for a liquid droplet radiator in space

Jinying YIN, Linhua LIU

《能源前沿（英文）》 2011年 第5卷 第2期   页码 166-173 doi: 10.1007/s11708-010-0105-y

摘要： The optimization of a space power system is greatly affected by the radiation heat transfer in a liquid droplet radiator (LDR). Radiation heat transfer in a two-dimensional bed of phase-change particle is modeled by solving the radiative transfer equation using the discrete ordinates method and the energy equation using the implicit finite difference method. The Mie theory is used to calculate the radiative properties of the droplet bed, whereas the effective medium theory is used to obtain the optical constants of partial solidification droplets. Multiple factors affect heat flux in the LDR, such as size distribution, flow velocity, phase change of droplets, layer thickness, droplet concentration in the layer, and material type of the work fluid; each of these must be analyzed. Calculations show that once size distribution is neglected, the relative error increases significantly. Size distribution has a remarkably strong effect on heat flux when the flow velocity of the working fluid is above 100 m/s. An increase in flow velocity leads to an increase in the total heat flux for the layer with a fixed volume fraction of droplets. The solidification zone occupies nearly half of the layer, and droplets of different sizes exhibit temperature differences to some extent due to local thermal non-equilibrium among them. Droplet concentration in the layer and the material type of the working fluid have strong effects on heat flux, whereas the thickness of the layer has a mild influence on heat flux.

关键词： radiation heat transfer     particle polydispersion     liquid droplet radiator     phase change    

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标题 作者 时间 类型 操作

Bicontinuous porous membranes with micro-nano composite structure using a facile atomization-assistednonsolvent induced phase separation method

期刊论文

Tuning of the active phase structure and hydrofining performance of alumina-supported tri-metallic WMoNi

Shufeng Shan, Haiyan Liu, Gang Shi, Xiaojun Bao

期刊论文

computational toolbox for molecular property prediction based on quantum mechanics and quantitative structure-property

期刊论文

Mesoscopic properties of dense granular materials: An overview

Qicheng SUN, Feng JIN, Guohua ZHANG

期刊论文

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

期刊论文

DyFe11Ti磁结构及其自旋重取向的中子衍射研究

Olivier Isnard, Eder J. Kinast

期刊论文

Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and hydrophilic drugs

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

期刊论文

非规则时序信息的结构转换及演化的细化分析

欧阳首承,张葵,郝丽萍,周莉蓉

期刊论文

Microfluidic production of liposomes through liquid–liquid phase separation in ternary droplets

期刊论文

Advances and perspectives in catalysts for liquid-phase oxidation of cyclohexane

Hui LI, Yuanbin SHE, Tao WANG

期刊论文

Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

期刊论文

Phase transition regulation and caloric effect

期刊论文

Effect of graphene and its derivatives on thermo-mechanical properties of phase change materials and

期刊论文

Distributed energy management for networked microgrids in a three-phase unbalanced distribution network

期刊论文

Analysis of the radiation heat transfer process of phase change for a liquid droplet radiator in space

Jinying YIN, Linhua LIU

期刊论文