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A Pt-Bi bimetallic nanoparticle catalyst for direct electro-oxidation of formic acid in fuel cells

Shu-Hong LI, Yue ZHAO, Jian CHU, Wen-Wei LI, Han-Qing YU, Gang LIU, Yang-Chao TIAN

《环境科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 388-394 doi: 10.1007/s11783-012-0475-y

摘要： Direct formic acid fuel cells are a promising portable power-generating device, and the development of efficient anodic catalysts is essential for such a fuel cell. In this work Pt-Bi nanoparticles supported on micro-fabricated gold wire array substrate were synthesized using an electrochemical deposition method for formic acid oxidation in fuel cells. The surface morphology and element components of the Pt-Bi/Au nanoparticles were characterized, and the catalytic activities of the three Pt-Bi/Au nanoparticle electrodes with different Pt/Bi ratios for formic acid oxidation were evaluated. It was found that Pt Bi /Au had a much higher catalytic activity than Pt Bi /Au and Pt Bi /Au, and Pt Bi /Au exhibited a current density of 2.7 mA·cm , which was 27-times greater than that of Pt/Au. The electro-catalytic activity of the Pt-Bi/Au electrode for formic acid oxidation increased with the increasing Bi content, suggesting that it would be possible to achieve an efficient formic acid oxidation on the low Pt-loading. Therefore, the Pt-Bi/Au electrode offers a promising catalyst with a high activity for direct oxidation of formic acid in fuel cells.

关键词： catalyst     electrochemical deposition     formic acid oxidation     fuel cell     gold wire array     microfabrication    

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Nanostructured gold films exhibiting almost complete absorption of light at visible wavelengths

Hanbin Zheng, Christine Picard, Serge Ravaine

《化学科学与工程前沿（英文）》 2018年 第12卷 第2期   页码 247-251 doi: 10.1007/s11705-018-1710-2

摘要： Nanostructured metal surfaces have been known to exhibit properties that deviate from that of the bulk material. By simply modifying the texture of a metal surface, various unique optical properties can be observed. In this paper, we present a simple two step electrochemical process combining electrodeposition and anodization to generate black gold surfaces. This process is simple, versatile and up-scalable for the production of large surfaces. The black gold films have remarkable optical behavior as they absorb more than 93% of incident light over the entire visible spectrum and also exhibit no specular reflectance. A careful analysis by scanning electron microscopy reveals that these unique optical properties are due to their randomly rough surface, as they consist in a forest of dendritic microstructures with a nanoscale roughness. This new type of black films can be fabricated to a large variety of substrates, turning them to super absorbers with potential applications in photovoltaic solar cells or highly sensitive detectors and so on.

关键词： nanostructuration     light absorption     coating     gold     electrodeposition     anodization    

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Elevated temperature creep model of parallel wire strands

《结构与土木工程前沿（英文）》   页码 1060-1071 doi: 10.1007/s11709-023-0981-y

摘要： Parallel wire strands (PWSs), which are widely used in prestressed steel structures, are typically in high-stress states. Under fire conditions, significant creep effects occur, reducing the prestress and influencing the mechanical behavior of PWSs. As there is no existing approach to analyze their creep behavior, this study experimentally investigated the elevated temperature creep model of PWSs. A charge-coupled camera system was incorporated to accurately obtain the deformation of the specimen during the elevated temperature creep test. It was concluded that the temperature level had a more significant effect on the creep strain than the stress level, and 450 °C was the key segment point where the creep rate varied significantly. By comparing the elevated temperature creep test results for PWSs and steel strands, it was found that the creep strain of PWSs was lower than that of steel strands at the same temperature and stress levels. The parameters in the general empirical formula, the Bailey–Norton model, and the composite time-hardening model were fitted based on the experimental results. By evaluating the accuracy and form of the models, the composite time-hardening model, which can simultaneously consider temperature, stress, and time, is recommended for use in the fire-resistance design of pre-tensioned structures with PWSs.

关键词： parallel wire strands     experimental study     elevated temperature creep model    

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Preconcentration of trace elements by adsorption onto a niobium wire for electrothermal atomization atomic

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 432-435 doi: 10.1007/s11705-012-1219-z

摘要： In the present work, a new preconcentration method of trace elements by adsorption onto a niobium wire has been developed for electrothermal atomization atomic absorption spectrometry (ETAAS) with a tungsten tube atomizer. Detection limits (pg·mL ) by this method combined with ETAAS were 45 for bismuth, 7.0 for cadmium, 20 for copper, 1.3 for gold, 36 for lead, 65 for manganese, 9.5 for rhodium and 19 for silver.

关键词： preconcentration     adsorption onto niobium wire     electrothermal atomization atomic absorption spectrometry     tungsten tube atomizer     trace elements    

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Catalytic decomposition of low level ozone with gold nanoparticles supported on activated carbon

Pengyi ZHANG , Bo ZHANG , Rui SHI ,

《环境科学与工程前沿（英文）》 2009年 第3卷 第3期   页码 281-288 doi: 10.1007/s11783-009-0032-5

摘要： Highly dispersed gold nanoparticles were supported on coal-based activated carbon (AC) by a sol immobilization method and were used to investigate their catalytic activity for low-level ozone decomposition at ambient temperature. Nitrogen adsorption-desorption, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts before and after ozone decomposition. The results showed that the supported gold nanoparticles prepared with microwave heating were much smaller and more uniformly dispersed on the activated carbon than those prepared with traditional conduction heating, exhibiting higher catalytic activity for ozone decomposition. The pH values of gold precursor solution significantly influenced the catalytic activity of supported gold for ozone decomposition, and the best pH value was 8. In the case of space velocity of 120000h, inlet ozone concentration of 50mg/m, and relative humidity of 45%, the Au/AC catalyst maintained the ozone removal ratio at 90.7% after 2500min. After being used for ozone decomposition, the surface carbon of the catalyst was partly oxidized and the oxygen content increased accordingly, while its specific surface area and pore volume only decreased a little. Ozone was mainly catalytically decomposed by the gold nanoparticles supported on the activated carbon.

关键词： ozone decomposition     activated carbon     gold nanoparticles     catalysis     sodium citrate     microwave    

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Numerical studies of dynamic behavior of liquid film on single-layer wire mesh with different wettabilities

《化学科学与工程前沿（英文）》   页码 1672-1680 doi: 10.1007/s11705-022-2205-8

摘要： Droplet impacting on the stainless steel wire mesh is very common in chemical devices, like a rotating packed bed. Surface wettability of wire mesh significantly affects the liquid flow pattern and liquid dispersion performance. However, the effect of surface wettability on the impaction phenomena at microscale such as liquid film is still unknown. In this work, the dynamic behavior of liquid film on the surface of wire mesh was analyzed by computational fluid dynamics simulation. The dynamic behavior of liquid film on the surface of wire mesh can be divided into the following three steps: (1) spreading step; (2) shrinkage process; (3) stabilizing or disappearing step. Effects of surface wettability, as well as operating conditions, on wetting area and liquid film thickness were studied. Compared to the hydrophilic wire mesh, the final wetting area of hydrophobic wire mesh is zero in most cases. The average liquid film thickness on the surface of hydrophilic wire mesh is 30.02–77.29 μm, and that of hydrophobic wire mesh is 41.76–237.37 μm. This work provided a basic understanding of liquid film flow at microscale on the surface with various surface wettabilities, which can be guiding the packing optimization and design.

关键词： stainless steel wire mesh     computational fluid dynamics     surface wettability     liquid film     impacting    

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oocyst directed assembly of gold nanoparticles and graphene oxide

Sona Jain, Zhicheng Huang, Brent R. Dixon, Syed Sattar, Juewen Liu

《化学科学与工程前沿（英文）》 2019年 第13卷 第3期   页码 608-615 doi: 10.1007/s11705-019-1813-4

摘要： Understanding the interactions between inorganic nanomaterials and biological species is an important topic for surface and environmental chemistry. In this work, we systematically studied the oocysts of as a model protozoan parasite and its interaction with gold nanoparticles (AuNPs) and graphene oxide (GO). The as-prepared citrate-capped AuNPs adsorb strongly on the oocysts leading to a vivid color change. The adsorption of the AuNPs was confirmed by transmission electron microscopy. Heat treatment fully inhibited the color change, indicating a large change of surface chemistry of the oocysts that can be probed by the AuNPs. Adding proteases such as trypsin and proteinase K partially inhibited the color change. DNA-capped AuNPs, on the other hand, could not be adsorbed by the oocysts. GO was found to wrap around the oocysts forming a conformal shell reflecting the shape of the oocysts. Both citrate-capped AuNPs and GO compromised the membrane integrity of the oocysts as indicated by the propidium iodide staining experiment, and they may be potentially used for inactivating the oocysts. This is the first example of using nanomaterials to probe the surface of the oocysts, and it suggests the possibility of using such organisms to template the assembly of nanomaterials.

关键词： nanomaterials     toxicology     water     biosensors    

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Experimental study on wire breakage detection by acoustic emission

Limin SUN, Ji QIAN

《结构与土木工程前沿（英文）》 2011年 第5卷 第4期   页码 503-509 doi: 10.1007/s11709-011-0132-8

摘要： This paper experimentally investigated wire breakage detection in a steel cable by acoustic emission (AE) waveform. In the experiments, the attenuation laws of waveform amplitudes were discussed based on stress wave propagation in the wire, which was generated by kNocking and wire breakage. Then the wave velocity was calculated based on the reach time of the stress wave from each sensor. Finally, based on the waveform attenuation laws and the linear position method, the amplitude and energy of the source were confirmed through the measured waveform to identify the source category. The experimental results illustrated that the stress wave from different sources has a different frequency spectrum, and the amplitude attenuation factor varied with the stress wave frequency; high frequency waves had a greater attenuation factor. Compared with the other source, the wire breakage source contained a much higher energy, and thus, the wire breakage signal can be distinguished from the other source by comparing the non-attenuation energy at the source position.

关键词： acoustic emission (AE)     waveform     wire breakage     attenuation factor     wave velocity    

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Gain-enhanced reconfigurable radiation array with mechanically driven system and directive elements

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0716-0

摘要： In the artificial intelligence-driven modern wireless communication system, antennas are required to be reconfigurable in terms of size according to changing application scenarios. However, conventional antennas with constant phase distributions cannot achieve enhanced gains in different reconfigurable sizes. In this paper, we propose a mechanically reconfigurable radiation array (RRA) based on miniaturized elements and a mechanically reconfigurable system to obtain gain-enhanced antennas in compact and deployed states. A five-element RRA with a phase-reconfigurable center element is designed and analyzed theoretically. The experimental sample has been fabricated, driven by a deployable frame with only one degree of freedom to realize the size and phase distribution reconfiguration simultaneously to validate the enhanced gains of RRA. The proposed RRA can be tessellated into larger arrays to achieve higher gains in other frequency regimes, such as terahertz or photonics applications with nanometer fabrication technology.

关键词： mechanism     reconfigurable radiation array (RRA)     compact state     deployed state     enhanced gain    

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Gold modified microelectrode for direct tetracycline detection

Hongtao WANG, Huimin ZHAO, Xie QUAN

《环境科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 313-319 doi: 10.1007/s11783-011-0323-5

摘要： The residues of tetracycline antibiotics in water have attracted many concerns due to their harmful impact to human health. This paper reports an electrochemical sensor for the determination of tetracycline (TC) by the microelectrode, which was fabricated by electrodeposited gold colloids on tungsten tip. Cyclic voltammerty was used to study the electrochemical behavior of TC on the microelectrode. Well anodic wave was obtained at about 1.5 V in acidic solutions. Electrochemical determination of tetracycline was investigated using microelectrode by cyclic voltammetry. Under optimized conditions, the calibration curves for TC were obtained. The oxidation peak currents were linearly related to TC concentrations in the range of 1–10 mg·L and 10–100 mg·L , respectively. The detection limit was 0.09 mg·L ( / = 3).

关键词： microelectrode     tungsten tip     gold colloids     tetracycline    

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游离磨料多股线线锯切割实验研究

王金生,姚春燕,彭伟,金鑫, 陈世杰

《中国工程科学》 2012年 第14卷 第11期   页码 94-98

摘要：

游离磨料线锯切割是将磨浆中的磨粒通过一定速度的细钢丝线带入切割区域，达到去除工件材料的目的。多股线由多根细金属线绕制而成，表面具有很多凹槽，与钢丝线光滑表面相比，可以输送更多的磨粒进入切割区域，从而提高切割效率。应用0.25 mm的多股线和0.25 mm的钢丝线对光学玻璃K9进行切割对比实验，结果表明，在相同工艺条件下，多股线的切割效率和表面粗糙度均优于钢丝线，但切缝宽度大于钢丝线。

关键词： 线锯     游离磨料加工     切割效率    

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evaluation methodology for masonry building and retrofitting using splint and bandage technique with wire

Pravin Kumar Venkat Rao PADALU; Yogendra SINGH

《结构与土木工程前沿（英文）》 2022年 第16卷 第4期   页码 478-505 doi: 10.1007/s11709-022-0817-1

摘要： The paper presents a seismic safety assessment of unreinforced masonry (URM) building using two approaches. The first approach uses the ‘Pier Analysis’ method, based on the concept of equivalent lateral stiffness, where in-plane and out-of-plane actions are considered independently. The second approach is developed with the program SAP2000, where the linear response is evaluated using continuum ‘finite element modelling’ (FEM). Both methods are compared to evaluate the safety of wall piers and the differences in the outcomes under combined gravitational and lateral seismic forces. The analysis results showed that few wall elements are unsafe in in-plane and out-of-plane tension. It is also observed that the pier analysis method is conservative compared to FEM, but can be used as a simplified and quick tool in design offices for safety assessment, with reasonable accuracy. To safeguard the URM wall piers under lateral loads, a retrofitting technique is adopted by providing vertical and horizontal belts called splints and bandages, respectively, using welded wire mesh (WWM) reinforcement. The study using the ‘Pier Analysis’ shows that the lateral load capacity of unsafe URM piers can be enhanced up to 3.67 times and made safe using the applied retrofitting technique. Further, the retrofitting design methodology and recommendations for application procedures to on-site URM buildings are discussed in detail.

关键词： unreinforced masonry     seismic in-plane and out-of-plane forces     pier analysis     finite element modelling     splint and bandage technique with wire mesh    

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Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

Zilin HUANG,Gang WANG,Shaopeng WEI,Changhong LI,Yiming RONG

《机械工程前沿（英文）》 2016年 第11卷 第3期   页码 242-249 doi: 10.1007/s11465-016-0397-7

摘要：

Laser hot wire cladding, with the prominent features of low heat input, high energy efficiency, and high precision, is widely used for remanufacturing metal parts. The cladding process, however, needs to be improved by using a quantitative method. In this work, volumetric defect ratio was proposed as the criterion to describe the integrity of forming quality for cladding layers. Laser deposition experiments with FV520B, one of martensitic stainless steels, were designed by using the Taguchi method. Four process variables, namely, laser power (P), scanning speed (Vs), wire feed rate (Vf), and wire current (I), were optimized based on the analysis of signal-to-noise (S/N) ratio. Metallurgic observation of cladding layer was conducted to compare the forming quality and to validate the analysis method. A stable and continuous process with the optimum parameter combination produced uniform microstructure with minimal defects and cracks, which resulted in a good metallurgical bonding interface.

关键词： process optimization     Taguchi method     signal-to-noise (S/N) ratio     volumetric defect ratio     laser hot wire cladding    

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Catalytic activities and mechanism of formaldehyde oxidation over gold supported on MnO

Guanglong PANG,Donghui WANG,Yunhong ZHANG,Chunyan MA,Zhengping HAO

《环境科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 447-457 doi: 10.1007/s11783-015-0808-8

摘要： MnO microspheres with various surface structures were prepared using the hydrothermal method, and Au/MnO catalysts were synthesized using the sol-gel method. We obtained three MnO microspheres and Au/MnO samples: coherent solid spheres covered with wire-like nanostructures, solid spheres with nanosheets, and hierarchical hollow microspheres with nanoplatelets and nanorods. We investigated the properties and catalytic activities of formaldehyde oxidation at room temperature. Crystalline structures of MnO are the main factor affecting the catalytic activities of these samples, and γ-MnO shows high catalytic performance. The excellent redox properties are responsible for the catalytic ability of γ-MnO . The gold-supported interaction can change the redox properties of catalysts and accelerate surface oxygen species transition, which can account for the catalytic activity enhancement of Au/MnO . We also studied intermediate species. The dioxymethylene (DOM) and formate species formed on the catalyst surface were considered intermediates, and were ultimately transformed into hydrocarbonate and carbonate and then decomposed into CO . A proposed mechanism of formaldehyde oxidation over Au/MnO catalysts was also obtained.

关键词： MnO2 microspheres     Au/MnO2     formaldehyde oxidation     γ-MnO2    

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Cystine-assisted accumulation of gold nanoparticles on ZnO to construct a sensitive surface-enhanced

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 15-23 doi: 10.1007/s11705-022-2177-8

摘要： Recently, various semiconductor/metal composites have been developed to fabricate surface-enhanced Raman spectroscopy substrates. However, low metal loading on semiconductors is still a challenge. In this study, cystine was introduced to increase the accumulation of gold nanoparticles on zinc oxide, owing to the biomineralization property of cystine. Morphological analysis revealed that the obtained ZnO/Au/cystine composite not only had a higher metal loading but also formed a porous structure, which is beneficial for Raman performance. Compared with ZnO/Au, the ZnO/Au/cystine substrate displayed a 40-fold enhancement in the Raman signal and a lower limit of detection (10–11 mol·L−1) in the detection of rhodamine 6G. Moreover, the substrate has favorable homogeneity and stability. Finally, ZnO/Au/cystine displayed excellent performance toward crystal violet and methylene blue in a test based on river water samples. This study provided a promising method to fabricate sensitive semiconductor/noble metal-based surface-enhanced Raman spectroscopy substrates for Raman detection.

关键词： biomineralization     cystine     semiconductor/metal composite     SERS detection     Raman detection    

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标题 作者 时间 类型 操作

A Pt-Bi bimetallic nanoparticle catalyst for direct electro-oxidation of formic acid in fuel cells

Shu-Hong LI, Yue ZHAO, Jian CHU, Wen-Wei LI, Han-Qing YU, Gang LIU, Yang-Chao TIAN

期刊论文

Nanostructured gold films exhibiting almost complete absorption of light at visible wavelengths

Hanbin Zheng, Christine Picard, Serge Ravaine

期刊论文

Elevated temperature creep model of parallel wire strands

期刊论文

Preconcentration of trace elements by adsorption onto a niobium wire for electrothermal atomization atomic

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

期刊论文

Catalytic decomposition of low level ozone with gold nanoparticles supported on activated carbon

Pengyi ZHANG , Bo ZHANG , Rui SHI ,

期刊论文

Numerical studies of dynamic behavior of liquid film on single-layer wire mesh with different wettabilities

期刊论文

oocyst directed assembly of gold nanoparticles and graphene oxide

Sona Jain, Zhicheng Huang, Brent R. Dixon, Syed Sattar, Juewen Liu

期刊论文

Experimental study on wire breakage detection by acoustic emission

Limin SUN, Ji QIAN

期刊论文

Gain-enhanced reconfigurable radiation array with mechanically driven system and directive elements

期刊论文

Gold modified microelectrode for direct tetracycline detection

Hongtao WANG, Huimin ZHAO, Xie QUAN

期刊论文

游离磨料多股线线锯切割实验研究

王金生,姚春燕,彭伟,金鑫, 陈世杰

期刊论文

evaluation methodology for masonry building and retrofitting using splint and bandage technique with wire

Pravin Kumar Venkat Rao PADALU; Yogendra SINGH

期刊论文

Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

Zilin HUANG,Gang WANG,Shaopeng WEI,Changhong LI,Yiming RONG

期刊论文

Catalytic activities and mechanism of formaldehyde oxidation over gold supported on MnO

Guanglong PANG,Donghui WANG,Yunhong ZHANG,Chunyan MA,Zhengping HAO

期刊论文

Cystine-assisted accumulation of gold nanoparticles on ZnO to construct a sensitive surface-enhanced

期刊论文