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One-step fabrication superhydrophobic sand filter for capillary-driven separation of water-in-oil emulsions

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Chinese Journal of Chemical Engineering 2021年第5期34卷 70-75页

作者： Bao wang Chaolang Chen Zhaoxin Li Jianfeng Wu Xianglou Liu jiadao wang Northeast Petroleum University Daqing 163318China Sate Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

The efficient separation of water-in-oil emulsion is of significance in environment and energy filed,and it has become a world-wide ***,we have presented a one-step,facile and low-cost approach to prepare superhydrophobic sands for efficient separation of water-in-oil *** as-prepared sand layers possessed a water contact angle higher than 151°,demonstrating their superior superhydrophobic ***,the as-prepared sand layers could separate water-in-emulsions with separation efficiency up to 99.7%,which is superior to both traditional and superwettable filtration *** effect of thickness of sand layer on separation performance was also *** results showed that the filtration flux decreased with the increased of filtration thickness while the separation efficiency *** as-prepared sand layer proposed by this study is a processing candidate for separating water-in-oil emulsion in practical ***,the as-prepared superhydrophobic sand fabrication method also provides an alternative for desert water storage.

关键词： Separation Filtration Superhydrophobic sand Preparation Emulsion

Fabrication of a micro-structured surface based on interfacial convection for drag reduction

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Chinese Science Bulletin 2011年第7期56卷 626-632页

作者： DOU ZhaoLiang wang jiadao YU Feng CHEN DaRong State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China China Ship Research and Development Academy Beijing 100192China

Based on interfacial convection in the presence of solvent evaporation, a novel method for the fabrication of a micro-structured surface is proposed to facilitate drag reduction. A mixture was coated on a substrate through a specially developed spray-painting system. Micron scale pits formed spontaneously in the coated surface because of interfacial convection and deformation driven by the gradient of the interfacial tension. Experimental results indicated that particles in the mixture played a crucial role in pit for-mation, and with a suitable selection of particle size and dosage, the characteristic parameters of the pitting could be controlled. The drag reduction experiments were first performed in a water tunnel, and the results showed that the micro-structured surface had a remarkable drag reduction performance over a great range of flow speeds.

关键词：界面张力梯度减阻性能微结构对流表面制备溶剂蒸发表面加工喷漆系统

Low-temperature activity and mechanism of WO_3-modified CeO_2-TiO_2 catalyst under NH_3-NO/NO_2 SCR conditions

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Chinese Journal of Catalysis 2018年第11期39卷 1804-1813页

作者： Lei Chen Ding Weng jiadao wang Duan Weng Li Cao State Key Laboratory of Tribology School of Mechanical EngineeringTsinghua UniversityBeijing 100084China Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

The CeO2‐TiO2(CeTi)and CeO2/WO3‐TiO2(CeWTi)catalysts were prepared by a sol‐gel precipitation method and their NH3‐NO/NO2 selective catalytic reduction(SCR)performance was studied.N2O formation and effect of oxygen concentration on SCR performance over CeWTi catalyst were also investigated while varying the NO2/NOx *** indicate that fast SCR behavior of CeWTi catalyst has the best NH3‐NO/NO2 SCR performance due to the catalyst reoxidation rate by NO2 higher than by *** with CeTi catalyst,CeWTi catalyst exhibits higher de‐NOx performance under NH3‐NO/NO2 SCR *** the CeTi and CeWTi catalysts exhibit similar redox property,addition of WO3 provides more acid sites which accelerate the reaction between NH4NO3 and NO to get a superior low‐temperature *** of N2O formation shows a peak at 250 oC mainly derived from NH4NO3 decomposition.

关键词： NH3‐NO/NO2 selective catalytic reduction CeWTi catalyst Surface acidity NH4NO3 Reaction mechanism

Equilibrium geometric structure and electronic properties of Cl and H_2O co-adsorption on Fe(100) surface

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Chinese Science Bulletin 2009年第8期54卷 1295-1301页

作者： ZHAO Wei wang jiadao LIU FengBin CHEN DaRong State Key Laboratory of Tribology Tsinghua University Beijing 100084 China

Based on the first principles density functional theory,the equilibrium geometric structure and surface electronic properties of Cl and H2O co-adsorption on the Fe(100) surface are *** results indicate that the optimal adsorption site for Cl and H2O co-adsorption on the Fe(100) surface is the location of Cl at the bridge site and H2O at the top *** with the Fe(100)/H2O adsorption system,remarkable changes in geometric structure and electronic properties occur,owing to the presence of Cl in the Fe(100)/(H2O+Cl) adsorption *** analysis of equilibrium geometric structure and surface electronic properties shows that the presence of Cl in the Fe(100)/(H2O+Cl) adsorption system unstablizes the Fe surface,making it easy to lose electrons.

关键词：平衡几何结构电子性质吸附位表面 Fe CI 密度泛函理论吸附系统

Effect of microparticle properties on erosion in solid-steam mixtures

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Chinese Science Bulletin 2011年第9期56卷 933-937页

作者： XU WanLi wang jiadao ZHAO Wei CHEN DaRong Beijing Petroleum Oil and Lubricant Institute Beijing 102300 China State Key Laboratory of Tribology Tsmghua University Beijing 100084 China

Based on a custom-built experimental apparatus, irregular microparticles of different sizes and microparticles of the same size but of different shape were added to wet steam, and erosion experiments were performed on polished medium carbon steel specimens. After the experiments, the eroded surfaces were analyzed by scanning electron microscopy and the degree of damage was evaluated by area loss. The results indicated that microparticle size significantly affects the degree of erosion damage. With an increase in size, variations in the method of damage mainly cause different degrees of damage on an eroded surface. Microparticle shape hardly affects the number of craters. Compared with spherical microparticles, irregular microparticles cause indentations more easily and result in more severe abrasion on the material’s surface.

关键词：固体微粒侵蚀实验湿蒸汽混合物扫描电子显微镜分析性能实验装置损害程度

Progress of marine biofouling and antifouling technologies

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Chinese Science Bulletin 2011年第7期56卷 598-612页

作者： Shan Cao jiadao wang HaoSheng Chen DaRong Chen Tsinghua Univ State Key Lab Tribol Beijing 100084 Peoples R China

Adhesion of marine fouling organisms on artificial surfaces such as ship hulls causes many problems, including extra energy consumption, high maintenance costs, and increased corrosion. Therefore, marine antifouling is an important issue. In this review, physical and biochemical developments in the field of marine biofouling, which involves biofilm formation and macro-organism settlement, are discussed. The major antifouling technologies based on traditional chemical methods, biological methods, and physical methods are presented. The chemical methods include self-polishing types such as tributyltin (TBT) self-polishing co- polymer coatings, which despite its good performance has been banned since 2008 because of its serious environmental impact. Therefore, other methods have been encouraged. These include coatings with copper compounds and biocide boosters to replace the TBT coatings. Biological extracts of secreted metabolites and enzymes are anticipated to act as antifoulants. Physical methods such as modification of surface topography, hydrophobic properties, and charge potential have also been considered to prevent biofouling. In this review, most of the current antifouling technologies are discussed. It is proposed that the physical antifouling technologies will be the ultimate antifouling solution, because of their broad-spectrum effectiveness and zero toxicity.

关键词：海洋生物污染防污技术物理方法丁基锡化合物化学方法生物杀灭剂能源消耗生物附着

Electronic structures of the oxygenated diamond (100) surfaces

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Chinese Science Bulletin 2006年第20期51卷 2437-2443页

作者： LIU Fengbin wang jiadao LIU Bing LI Xuemin CHEN Darong State Key Laboratory of Tribology Tsinghua University Beijing 100084 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

By means of first principles method on the basis of density functional theory (DFT), the equi- librium geometries and density of states (DOS) of the two oxygenated diamond (100) surfaces, bridging model and on-top model are calculated. The results indicate that there are no surface states located in the band gap of the bridging model of oxygenated dia- mond (100) surface, and the occupied surface states in the valence band are attributed to the non-bonded O 2p orbital, O 2p and C 2p bonding orbitals, and C 2p and H 1s bonding orbitals. By contrast, for the on-top model of oxygenated diamond (100) surface, the unoccupied surface states exist in the band gap, which originate from non-bonded C 2p and O 2p or- bitals. In addition, the occupied surface states in the valence band are induced by non-bonded O 2p or- bital and the C==O π bond.

关键词：钻石电子结构氧化摩擦密度功能理论剪切模型

Water erosion mechanism of mild carbon steels induced by micro-particles

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Chinese Science Bulletin 2009年第24期54卷 4577-4582页

作者： XU WanLi QIN Li wang jiadao CHEN HaoSheng CHEN DaRong State Key Laboratory of Tribology Tsinghua University Beijing 100084 China

To clarify the water erosion mechanism of the mild carbon steels, the water erosion experiments were performed by using deionized water as steam source. The results showed that under the damage threshold velocity of liquid impact, the material surface would not be destroyed. However, when the micro-particles were added into the steam, the pits appeared on the surface soon. By comparison, it is found that the pits are quite different from those induced by micro-particles impact without steam, but similar to those induced by cavitation erosion. The results indicated that the water erosion mechanism was similar to that of cavitation erosion under the damage threshold velocity. The micro-particles carry the micro-bubbles to approach the surface of the material, and the micro-bubbles collapse and generate micro-jet to impinge vertically on the surface, which lead to the produce of pits.

关键词：腐蚀机理钢水诱导微颗粒微观粒子碳阈值速度冲击损伤

Affected zone generated around the erosion pit on carbon steel surface at the incipient stage of vibration cavitation

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Chinese Science Bulletin 2008年第6期53卷 943-947页

作者： CHEN HaoShenh LI Jiang LIU ShiHan CHEN DaRong wang jiadao State Key Laboratory of Tribology Tsinghua University Beijing 100084 China Mechanical Engineering School University of Science and Technology Beijing Beijing 100083 China

The characteristics of erosion pits on a carbon steel surface were investigated at the incipient stage of cavitation erosion. After a 5-minute experiment performed in an ultrasonic vibration system, needle-like erosion pits appeared on the polished steel surface, and a specially affected zone was formed around the pit. The shape of the pit and the plastic deformation of the affected zone indicate that the me- chanical impaction on the surface is the main reason for the cavitation damage. On the other hand, the iridescent color, the decreased surface hardness and the precipitated carbides on the affected zone prove that the affected zone has experienced a tempering process with the temperature higher than 300°C. The lack of oxygen in the affected zone also proves that it is not a chemical oxygen result. A special phenomenon that a carbon ring forms in the affected zone is explained as a result of the toroidal bubbles' heating effect at the final stage of the bubble collapse.

关键词：气蚀热效应超声波振动碳钢表面腐蚀