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Bicontinuous porous membranes with micro-nano composite structure using a facile atomization-assisted

《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    

Fabrication and in vivo evaluation of Ti6Al4V implants with controlled porous structure and complex shape

Xiang LI, Yun LUO, Chengtao WANG, Wenguang ZHANG, Yuanchao LI

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 66-71 doi: 10.1007/s11465-012-0302-y

摘要:

Electron beam melting process was used to fabricate porous Ti6Al4V implants. The porous structure and surface topography of the implants were characterized by scanning electron microscopy (SEM) and digital microscopy (DM). The results showed that the pore size was around 600 and the porosity approximated to 57%. There was about±50 μm of undulation on implants surfaces. Standard implants and a custom implant coupled with porous sections were designed and fabricated to validate the versatility of the electron beam melting (EBM) technique. After coated with bone-like apatite, samples with fully porous structures were implanted into cranial defects in rabbits to investigate the in vivo performance. The animals were sacrificed at 8 and 12 weeks after implantation. Bone ingrowth into porous structure was examined by histological analysis. The histological sections indicated that a large amount of new bone formation was observed in porous structure. The newly formed bone grew from the calvarial margins toward the center of the bone defect and was in close contact with implant surfaces. The results of the study showed that the EBM produced Ti6Al4V implants with well-controlled porous structure, rough surface topography and bone-like apatite layer are beneficial for bone ingrowth and apposition.

关键词: electron beam melting process     implant     porous structure     bone ingrowth    

波浪与外壁透空双筒柱的互相作用

滕斌,李玉成,孙路

《中国工程科学》 2001年 第3卷 第10期   页码 41-47

摘要:

对于波浪与透空外壁同轴双筒柱的相互作用问题,利用速度势的特征函数展开式和透空壁内流体速度与两壁间压力差成正比的线性模型,建立了一个线性解析解。应用这一模型开展了数值实验,用以检验孔隙系数和透空部分大小以及内外柱径之比对双筒柱上波浪力和波面高度的影响。计算结果表明,外壁孔隙系数和透空部分大小对波面升高和波浪荷载有很大影响,通过调整各个系数,应用双筒透空柱可以减小周围的波面高度及其上的波浪荷载。

关键词: 波浪绕射     波浪力     波面升高     有孔建筑     圆柱    

喷气发动机部件的增材设计与制造

韩品连

《工程(英文)》 2017年 第3卷 第5期   页码 648-652 doi: 10.1016/J.ENG.2017.05.017

摘要:

喷气发动机部件的增材设计(AD)和增材制造(AM)将彻底改变传统的航空航天工业。增材设计的独特性开创了喷气发动机设计和制造的新方向,比如梯度材料和微观结构。工程师已经从传统方法和技术的诸多限制中解放出来。增材制造过程最重要的特征之一是其可以确保零件的一致性,因为它始于点,继而到线和层面,直至整个部件完成。设计和制造之间的协调是空气动力学、热力学、结构整合、传热、材料开发和加工等方面取得成功的关键。工程师必须改变设计零件的方式,因为他们要从传统的“减材”方法转移到“增材”的新方法来制造零件。增材设计与增材制造设计不一样。我们需要一种新方法和新工具来协助这种新的设计和制方式。本文详细讨论了增材设计与增材制造中的需求,以及如何解决当前的问题。

关键词: 增材制造     增材设计     喷气发动机     多孔结构    

polybenzoxazine-based carbon microspheres with nitrogen functionalities: Effects of mixed solvents on pore structure

Uthen Thubsuang, Suphawadee Chotirut, Apisit Thongnok, Archw Promraksa, Mudtorlep Nisoa, Nicharat Manmuanpom, Sujitra Wongkasemjit, Thanyalak Chaisuwan

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 1072-1086 doi: 10.1007/s11705-019-1899-8

摘要: In this study, polybenzoxazine (PBZ)-based carbon microspheres were prepared via a facile method using a mixture of formaldehyde (F) and dimethylformamide (DMF) as the solvent. The PBZ microspheres were successfully obtained at the F/DMF weight ratios of 0.4 and 0.6. These microspheres exhibited high nitrogen contents after carbonization. The microstructures of all the samples showed an amorphous phase and a partial graphitic phase. The porous carbon with the F/DMF ratio of 0.4 showed significantly higher specific capacitance (275.1 F g ) than the reference carbon (198.9 F g ) at 0.05 A g . This can be attributed to the synergistic electrical double-layer capacitor and pseudo-capacitor behaviors of the porous carbon with the F/DMF ratio of 0.4. The presence of nitrogen/oxygen functionalities induced pseudo-capacitance in the microspheres, and hence increased their total specific capacitance. After activation with CO , the specific surface area of the carbon microspheres with the F/DMF ratio of 0.4 increased from 349 to 859 m g and the specific capacitance increased to 424.7 F g . This value is approximately two times higher than that of the reference carbon. The results indicated that the F/DMF ratio of 0.4 was suitable for preparing carbon microspheres with good supercapacitive performance. The nitrogen/oxygen functionalities and high specific surface area of the microspheres were responsible for their high capacitance.

关键词: PBZ     carbon     porous materials     microsphere     supercapacitor    

Fabricating sustainable lignin-derived porous carbon as electrode for high-performance supercapacitors

《化学科学与工程前沿(英文)》 2023年 第17卷 第8期   页码 1065-1074 doi: 10.1007/s11705-023-2313-0

摘要: Lignocellulosic biomass such as plants and agricultural waste are ideal to tackle the current energy crisis and energy-related environmental issues. Carbon-rich lignin is abundant in lignocellulosic biomass, whose high-value transformation and utilization has been the most urgent problem to be solved. Herein, we propose a method for the preparation of porous carbon from lignin employing an H3PO4-assisted hydrothermal method. We characterize the as-prepared lignin-derived porous carbon and investigate its potential for energy storage. After assisted hydrothermal treatment followed by carbonization at 800 °C, the lignin-derived porous carbon displays a high specific capacitance (223.6 F·g–1 at 0.1 A·g–1) and excellent cycling ability with good capacitance retention. In this present study, the resultant lignin-derived porous carbon was used as the electrode of a supercapacitor, illustrating yet another potential high-value use for lignin, namely as a candidate for the sustainable fabrication of main supercapacitor components.

关键词: lignin     porous carbon     electrode     supercapacitor    

Optimized porous clay heterostructure for removal of acetaldehyde and toluene from indoor air

Pu ZHAO,Lizhong ZHU

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 219-228 doi: 10.1007/s11783-014-0760-z

摘要: Adsorption is the most widely used technology for the removal of indoor volatile organic compounds (VOCs). However, existing adsorbent-based technologies are inadequate to meet the regulatory requirement, due to their limited adsorption capacity and efficiency, especially under high relative humidity (RH) conditions. In this study, a series of new porous clay heterostructure (PCH) adsorbents with various ratios of micropores to mesopores were synthesized, characterized and tested for the adsorption of acetaldehyde and toluene. Two of them, PCH25 and PCH50, exhibited markedly improved adsorption capability, especially for hydrophilic acetaldehyde. The improved adsorption was attributed to their large micropore areas and high micropore-to-mesopore volume ratios. The amount of acetaldehyde adsorbed onto PCH25 at equilibrium reached 62.7 mg·g , eight times as much as the amount adsorbed onto conventional activated carbon (AC). Even at a high RH of 80%, PCH25 removed seven and four times more of the acetaldehyde than AC and the unmodified raw PCHs did, respectively. This new PCH optimized for their high adsorption and resistance to humidity has promising applications as a cost-effective adsorbent for indoor air purification.

关键词: porous clay heterostructure     volatile organic compounds     adsorption     adsorbent     indoor air    

Maximum entropy based finite element analysis of porous media

Emad NOROUZI, Hesam MOSLEMZADEH, Soheil MOHAMMADI

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 364-379 doi: 10.1007/s11709-018-0470-x

摘要: The maximum entropy theory has been used in a wide variety of physical, mathematical and engineering applications in the past few years. However, its application in numerical methods, especially in developing new shape functions, has attracted much interest in recent years. These shape functions possess the potential for performing better than the conventional basis functions in problems with randomly generated coarse meshes. In this paper, the maximum entropy theory is adopted to spatially discretize the deformation variable of the governing coupled equations of porous media. This is in line with the well-known fact that higher-order shape functions can provide more stable solutions in porous problems. Some of the benchmark problems in deformable porous media are solved with the developed approach and the results are compared with available references.

关键词: maximum entropy FEM     fully coupled multi-phase system     porous media    

S-enriched porous polymer derived N-doped porous carbons for electrochemical energy storage and conversion

Chao Zhang, Chenbao Lu, Shuai Bi, Yang Hou, Fan Zhang, Ming Cai, Yafei He, Silvia Paasch, Xinliang Feng, Eike Brunner, Xiaodong Zhuang

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 346-357 doi: 10.1007/s11705-018-1727-6

摘要:

Porous polymers have been recently recognized as one of the most important precursors for fabrication of heteroatom-doped porous carbons due to the intrinsic porous structure, easy available heteroatom-containing monomers and versatile polymerization methods. However, the heteroatom elements in as-produced porous carbons are quite relied on monomers. So far, the manipulating of heteroatom in porous polymer derived porous carbons are still very rare and challenge. In this work, a sulfur-enriched porous polymer, which was prepared from a diacetylene-linked porous polymer, was used as precursor to prepare S-doped and/or N-doped porous carbons under nitrogen and/or ammonia atmospheres. Remarkably, S content can sharply decrease from 36.3% to 0.05% after ammonia treatment. The N content and specific surface area of as-fabricated porous carbons can reach up to 1.32% and 1508 m2·g−1, respectively. As the electrode materials for electrical double-layer capacitors, as-fabricated porous carbons exhibit high specific capacitance of up to 431.6 F·g−1 at 5 mV·s−1 and excellent cycling stability of 99.74% capacitance retention after 3000 cycles at 100 mV·s−1. Furthermore, as the electrochemical catalysts for oxygen reduction reaction, as-fabricated porous carbons presented ultralow half-wave-potential of 0.78 V versus RHE. This work not only offers a new strategy for manipulating S and N doping features for the porous carbons derived from S-containing porous polymers, but also paves the way for the structure-performance interrelationship study of heteroatoms co-doped porous carbon for energy applications.

关键词: porous polymers     porous carbons     sulfur and nitrogen doping     supercapacitor    

Hierarchically porous materials: Synthesis strategies and emerging applications

Minghui Sun, Chen Chen, Lihua Chen, Baolian Su

《化学科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 301-347 doi: 10.1007/s11705-016-1578-y

摘要: Great interests have arisen over the last decade in the development of hierarchically porous materials. The hierarchical structure enables materials to have maximum structural functions owing to enhanced accessibility and mass transport properties, leading to improved performances in various applications. Hierarchical porous materials are in high demand for applications in catalysis, adsorption, separation, energy and biochemistry. In the present review, recent advances in synthesis routes to hierarchically porous materials are reviewed together with their catalytic contributions.

关键词: hierarchically porous materials     synthesis     application    

Boron and nitrogen co-doped porous carbon derived from sodium alginate enhanced capacitive deionization

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2014-2024 doi: 10.1007/s11705-023-2346-4

摘要: Capacitive deionization can alleviate water shortage and water environmental pollution, but performances are greatly determined by the electrochemical and desalination properties of its electrode materials. In this work, B and N co-doped porous carbon with micro-mesoporous structures is derived from sodium alginate by a carbonization, activation, and hydrothermal doping process, which exhibits large specific surface area (2587 m2·g‒1) and high specific capacitance (190.7 F·g‒1) for adsorption of salt ions and heavy metal ions. Furthermore, the materials provide a desalination capacity of 26.9 mg·g−1 at 1.2 V in 500 mg·L‒1 NaCl solution as well as a high removal capacity (239.6 mg·g‒1) and adsorption rate (7.99 mg·g‒1·min‒1) for Pb2+ with an excellent cycle stability. This work can pave the way to design low-cost porous carbon with high-performances for removal of salt ions and heavy metal ions.

关键词: capacitance deionization     porous carbon     B/N co-doping     heavy metal ions     water purification    

The role of single deformed bubble on porous foam tray with submerged orifices on the mass transfer enhancement

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2127-2143 doi: 10.1007/s11705-023-2363-3

摘要: Foam trays with porous submerged orifices endow bubbles uniformly distributed, which are considered attractive column internals to enhance the gas-liquid mass transfer process. However, its irregular orifice and complex gas-liquid flow make it lack pore-scale investigations concerning the transfer mechanism of dynamic bubbling. In this work, the actual porous structure of the foam tray is obtained based on micro computed tomography technology. The shape, dynamic, and mass transfer of rising bubbles at porous orifices are investigated using the volume of fluid and continue surface force model. The results demonstrate that the liquid encroaching on the gas channels causes the increasing orifices velocity, which makes the trailing bubble easily detach from the midst of the leading bubble and causes pairing coalescence. Additionally, we found that the central breakup regimes significantly improve the gas-liquid interface area and mass transfer efficiency. This discovery exemplifies the mechanism of mass transfer intensification for foam trays and serves to promote its further development.

关键词: bubble formation     porous submerged orifices     process intensification     foam tray    

An investigation on prevalent strategies for XFEM-based numerical modeling of crack growth in porous

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 914-936 doi: 10.1007/s11709-021-0750-8

摘要: Crack growth modeling has always been one of the major challenges in fracture mechanics. Among all numerical methods, the extended finite element method (XFEM) has recently attracted much attention due to its ability to estimate the discontinuous deformation field. However, XFEM modeling does not directly lead to reliable results, and choosing a strategy of implementation is inevitable, especially in porous media. In this study, two prevalent XFEM strategies are evaluated: a) applying reduced Young’s modulus to pores and b) using different partitions to the model and enriching each part individually. We mention the advantages and limitations of each strategy via both analytical and experimental validations. Finally, the crack growth is modeled in a natural porous media (Fontainebleau sandstone). Our investigations proved that although both strategies can identically predict the stress distribution in the sample, the first strategy simulates only the initial crack propagation, while the second strategy could model multiple cracks growths. Both strategies are reliable and highly accurate in calculating the stress intensity factor, but the second strategy can compute a more reliable reaction force. Experimental tests showed that the second strategy is a more accurate strategy in predicting the preferred crack growth path and determining the maximum strength of the sample.

关键词: numerical modeling     extended finite element method     porous media     crack growth     stress intensity factor    

Electrodeposited porous Pb electrode with improved electrocatalytic performance for the electroreduction

Jing WANG, Hua WANG, Zhenzhen HAN, Jinyu HAN

《化学科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 57-63 doi: 10.1007/s11705-014-1444-8

摘要: A porous Pb foam was fabricated electrochemically at a copper substrate and then used as the cathode for the electroreduction of CO . The surface morphology and composition of the porous Pb electrode was characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and selected area electron diffraction. The honeycomb-like porous structure was composed of needle-like Pb deposits. Cyclic voltammetry studies demonstrated that the porous Pb electrode had better electrocatalytic performance for the formation of formic acid from CO compared with a Pb plate electrode. The increase in current density was due to the large surface area of the porous Pb electrode, which provides more active sites on the electrode surface. The improved formic acid selectivity was due to the morphology of the roughened surface, which contains significantly more low-coordination sites which are more active for CO reduction. The highest current efficiency for formic acid was 96.8% at -1.7 V versus saturated calomel electrode at 5 °C. This porous Pb electrode with good catalytic abilities represents a new 3D porous material with applications for the electroreduction of CO .

关键词: electrodeposited porous Pb     carbon dioxide     electroreduction     formic acid    

Permeability analysis and seepage process study on crystal layer in melt crystallization with fractal and porous

Xiaobin JIANG, Baohong HOU, Yongli WANG, Jingkang WANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 435-441 doi: 10.1007/s11705-011-1139-3

摘要: In this paper a porous media seepage model was applied to analyze the permeability and study the seepage process of crystal pillar formed in the preparation of electronic grade phosphoric acid (EGPA). By inspecting the seeping process, the structure parameter of crystal pillar could be obtained. Two basic ideal models (perfectly separated model and perfectly connected model) were presented and a characterized factor was introduced to modify the model. A good simulation result was obtained which met the experiment result well. The relationship between and permeability were also discussed. The characterized factor showed potential application on optimizing process.

关键词: melt crystallization     porous media     fractal     permeability     hyperpure material     simulation    

标题 作者 时间 类型 操作

Bicontinuous porous membranes with micro-nano composite structure using a facile atomization-assisted

期刊论文

Fabrication and in vivo evaluation of Ti6Al4V implants with controlled porous structure and complex shape

Xiang LI, Yun LUO, Chengtao WANG, Wenguang ZHANG, Yuanchao LI

期刊论文

波浪与外壁透空双筒柱的互相作用

滕斌,李玉成,孙路

期刊论文

喷气发动机部件的增材设计与制造

韩品连

期刊论文

polybenzoxazine-based carbon microspheres with nitrogen functionalities: Effects of mixed solvents on pore structure

Uthen Thubsuang, Suphawadee Chotirut, Apisit Thongnok, Archw Promraksa, Mudtorlep Nisoa, Nicharat Manmuanpom, Sujitra Wongkasemjit, Thanyalak Chaisuwan

期刊论文

Fabricating sustainable lignin-derived porous carbon as electrode for high-performance supercapacitors

期刊论文

Optimized porous clay heterostructure for removal of acetaldehyde and toluene from indoor air

Pu ZHAO,Lizhong ZHU

期刊论文

Maximum entropy based finite element analysis of porous media

Emad NOROUZI, Hesam MOSLEMZADEH, Soheil MOHAMMADI

期刊论文

S-enriched porous polymer derived N-doped porous carbons for electrochemical energy storage and conversion

Chao Zhang, Chenbao Lu, Shuai Bi, Yang Hou, Fan Zhang, Ming Cai, Yafei He, Silvia Paasch, Xinliang Feng, Eike Brunner, Xiaodong Zhuang

期刊论文

Hierarchically porous materials: Synthesis strategies and emerging applications

Minghui Sun, Chen Chen, Lihua Chen, Baolian Su

期刊论文

Boron and nitrogen co-doped porous carbon derived from sodium alginate enhanced capacitive deionization

期刊论文

The role of single deformed bubble on porous foam tray with submerged orifices on the mass transfer enhancement

期刊论文

An investigation on prevalent strategies for XFEM-based numerical modeling of crack growth in porous

期刊论文

Electrodeposited porous Pb electrode with improved electrocatalytic performance for the electroreduction

Jing WANG, Hua WANG, Zhenzhen HAN, Jinyu HAN

期刊论文

Permeability analysis and seepage process study on crystal layer in melt crystallization with fractal and porous

Xiaobin JIANG, Baohong HOU, Yongli WANG, Jingkang WANG

期刊论文