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Brazing of ceramic-to-ceramic and ceramic-to-metal joints in air

Kirsten BOBZIN, Thomas SCHLAEFER, Lidong ZHAO, Nils KOPP, Arne SCHLEGEL

《机械工程前沿（英文）》 2010年 第5卷 第2期   页码 125-129 doi: 10.1007/s11465-010-0007-z

摘要： Reactive air brazing (RAB) is an emerging technology for the production of ceramic-to-ceramic and ceramic-to-metal joints. In this study, RAB was investigated with respect to the potential applications for solid oxide fuel cells (SOFCs) as one example of use. It was found that alumina could be well brazed by RAB with AgCu and AgCuTi brazes. Both braze composition and brazing temperature influenced significantly the wetting behavior and their mechanism of wetting. AgCu and AgCuTi braze alloys could also be used to produce brazed joints with the SOFC materials ceramic yttria stabilized zirconia and steel X1CrTiLa22. However, CuO reacts with the steel, forming a brittle oxide layer on the steel surface, which is undesirable for SOFC applications. The first trials with Ag0.5Al showed a promising solution.

关键词： reactive air brazing (RAB)     X1CrTiLa22     Al2O3     yttria stabilized zirconia (YSZ)     solid oxide fuel cell (SOFC)    

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Preparation and characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball milling

Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 176-181 doi: 10.1007/s11465-011-0220-4

摘要：

High-energy ball milling is an effective method to produce nanocrystalline oxides. In this study, a conventional ZrO2-7%Y2O3spray powder was ball-milled to produce nanocrystalline powders with high levels of crystalline disorders for deposition of thermal barrier coatings. The powder was milled both with 100Cr6 steel balls and with ZrO2-3%Y2O3 ceramic balls as grinding media. The milling time was varied in order to investigate the effect of the milling time on the crystallite size. The powders were investigated in terms of their crystallite sizes and morphologies by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that under given milling conditions the powder was already nanostructured after 40 min milling. The crystallite size decreased significantly with increasing milling time within first 120 min. After that, a further increase of milling time did not lead to a significant reduction of the crystallite size. Ball-milling led to lattice microstrains. Milling with the steel balls resulted in finer nano-sized crystal grains, but caused the contamination of the powder. The nano-sized crystal grains coarsened during the heat-treatment at 1250°C.

关键词： nanostrucured powders     yttria stabilized zirconia (YSZ)     high-energy ball milling     thermal barrier coatings    

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Selective conversion of cellulose to hexitols over bi-functional Ru-supported sulfated zirconia and silica-zirconia

Zhiqiang Song,Hua Wang,Yufei Niu,Xiao Liu,Jinyu Han

《化学科学与工程前沿（英文）》 2015年 第9卷 第4期   页码 461-466 doi: 10.1007/s11705-015-1543-1

摘要： We report a process of selective conversion of microcrystalline cellulose to hexitols over bi-functional Ru-supported sulfated zirconia and silica-zirconia catalysts. A 58.1% yield of hexitols and a 71.0% conversion of cellulose were achieved over Ru/SZSi(100:15)-773 catalyst at 443 K. The as-synthesized catalysts were characterized by X-ray diffraction (XRD), BET, thermogravimetric analysis and pyridine adsorption Fourier transform infrared spectroscopy (FTIR). XRD results indicated that the sulfated catalysts were pure tetragonal phase of ZrO when calcined at 773 K. Monoclinic zirconia appeared at the calcination temperature of 873 K, and the content of monoclinic phase increased with the elevating temperature. Compared with sulfated zirconia catalyst, sulfated silica-zirconia catalysts possessed a higher ratio of Brønsted to Lewis on the surface of catalysts, as shown from pyridine adsorption FTIR results. The reaction results indicated that the tetragonal zirconia, which is necessary for the formation of superacidity, was the active phase to cellulose conversion. The higher amounts of Brønsted acid sites can remarkably accelerate the cellulose depolymerization and promote side reactions that convert C5–C6 alcohols into the unknown soluble degradation products.

关键词： hexitols     cellulose     hydrogenation     sulfated zirconia     ruthenium    

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Mechanical properties of stabilized artificial organic soil

XU Riqing, GUO Yin, LIU Zengyong

《结构与土木工程前沿（英文）》 2008年 第2卷 第2期   页码 161-165 doi: 10.1007/s11709-008-0023-9

摘要： In order to study the influence of organic matter on the mechanical properties of stabilized soil and the effect of XGL2005 on stabilizing organic soil, unconfined compressive strength tests were carried out. Test results indicated that the strength of stabilized soil decreased in the form of a logarithmic function as the organic matter content increased. In contrast, the strength increased in the form of a power function as the content of the stabilization agent increased. The strength of cement stabilized organic soil was reinforced greatly by adding the stabilizer XGL2005. Based on the law obtained from the test, a strength prediction model was established by regression analysis. The model included the influence of the curing time, the content of the cement, the organic matter content and the stabilization agent on the strength of stabilized soil.

关键词： compressive strength     stabilized     stabilization     regression analysis     stabilizer XGL2005    

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Effect of alumina and zirconia as binders on the activity of Fe-BEA for NH

Jin Shi, Zihao Zhang, Mingxia Chen, Zhixiang Zhang, Wenfeng Shangguan, Shunchao Gu, Hirano Shin-ichi

《环境科学与工程前沿（英文）》 2018年 第12卷 第1期 doi: 10.1007/s11783-018-1012-4

摘要： Fe-BEA catalysts are active for the NH -SCR of NO. For industrial application, a binder should be added to the Fe-BEA catalysts to make them tightly adhere to the monoliths. The addition of alumina and zirconia as binders to the Fe-BEA led to a different effect on NO conversion. The catalytic activity of the mixed samples was evaluated by the temperature programmed procedure in a flow-reactor system, and the mechanism was analyzed via SEM, BET, XRD and XPS. It was found that larger iron particles were formed by the migration of parent iron particles in the Fe-BEA catalyst with alumina. This led to the increase of Fe magnitude and iron cluster, enhancing the abilities of NO oxidation and storage. Accordingly, the SCR activity increased slightly in low temperature but decreased sharply in high temperature. For the Fe-BEA with zirconia sample, NO oxidation and storage abilities decreased due to the less iron clusters. The increase of Fe magnitude resulted in higher catalytic oxidation ability, which gave rise to little change in the SCR activity compared with the Fe-BEA.

关键词： NH3-SCR     NO     Fe-BEA     Binder     Alumina     Zirconia    

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total oxidizable carbon, phosphate and various metallic ions from HO solution with amino-functionalized zirconia

《化学科学与工程前沿（英文）》 2023年 第17卷 第4期   页码 470-482 doi: 10.1007/s11705-022-2231-6

摘要： Amino-functionalized zirconia was synthesized by the co-condensation method using zirconium butanol and 3-aminopropyltriethoxy silane for the simultaneous removal of various impurities from aqueous 30% H2O2 solution. The results of Fourier transform infrared (FTIR) and Zeta potential showed that the content of N in amino-functionalized zirconia increased with the added amount of 3-aminopropyltriethoxy silane. Accordingly, the removal efficiency of total oxidizable carbon, phosphate and metallic ions from the H2O2 solution increased. The adsorbent with an N content of 1.62% exhibited superior adsorption performance. The removal efficiency of 82.7% for total oxidizable carbon, 34.2% for phosphate, 87.1% for Fe3+, 83.2% for Al3+, 55.1% for Ca2+ and 66.6% for Mg2+, with a total adsorption capacity of 119.6 mg·g–1, could be achieved. The studies conducted using simulated solutions showed that the adsorption process of phosphate on amino-functionalized zirconia is endothermic and spontaneous, and the behaviors could be well described by the pseudo-second-order model and Langmuir model with a maximum adsorption capacity of 186.7 mg·g–1. The characterizations of the spent adsorbents by Zeta potential, FTIR and X-ray photoelectron spectroscopy revealed that the adsorption mechanism of phosphate is predominantly electrostatic attraction by the protonated functional groups and complementary ligand exchange with zirconium hydroxyl groups.

关键词： adsorption     zirconia     total oxidizable carbon     phosphate     metallic ions     hydrogen peroxide    

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Biopolymer-stabilized emulsions on the basis of interactions between β -lactoglobulin and ι -carrageenan

Qiaomei RU, Younghee CHO, Qingrong HUANG,

《化学科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 399-406 doi: 10.1007/s11705-009-0253-y

摘要： -Carrageenan and -lactoglobulin (-lg) stabilized oil-in-water (O/W) emulsions, which can be used for the oral administration of bioactive but environmentally sensitive ingredients, have been successfully prepared. The effects of protein/polysaccharide ratios, total biopolymer concentration, environmental stress (thermal processing and sonication), and pH on the complex formation between -carrageenan and -lactoglobulin have been investigated. We found that -lactoglobulin and-carrageenan stabilized emulsions can be formed at pH values of 6.0, 4.0, and 3.4. However, the microstructures of emulsions stabilized by -lactoglobulin and -carrageenan was identified by optical microscopy, and it indicated that the emulsion prepared at pH 6.0 flocculated more extensively, while its hydrodynamic radius was much bigger than those prepared at pH 4.0 and 3.4. Regarding rheological properties, the emulsion of pH 6.0 showed a more solid-like behavior but with a lower viscosity than those of pH 4.0 and 3.4. The optimum concentration ranges for -lg and-carrageenan to form stable emulsions at pH 4.0 and 3.4 were 0.3wt-%―0.6wt-% and 0.4wt-%―0.7wt-%, respectively.
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High-precision gyro-stabilized control of a gear-driven platform with a floating gear tension device

《机械工程前沿（英文）》 2021年 第16卷 第3期   页码 487-503 doi: 10.1007/s11465-021-0635-5

摘要： This study presents an improved compound control algorithm that substantially enhances the anti-disturbance performance of a gear-drive gyro-stabilized platform with a floating gear tension device. The tension device can provide a self-adjustable preload to eliminate the gap in the meshing process. However, the weaker gear support stiffness and more complex meshing friction are also induced by the tension device, which deteriorates the control accuracy and the ability to keep the aim point of the optical sensors isolated from the platform motion. The modeling and compensation of the induced complex nonlinearities are technically challenging, especially when base motion exists. The aim of this research is to cope with the unmeasured disturbances as well as the uncertainties caused by the base lateral motion. First, the structural properties of the gear transmission and the friction-generating mechanism are analyzed, which classify the disturbances into two categories: Time-invariant and time-varying parts. Then, a proportional-integral controller is designed to eliminate the steady-state error caused by the time-invariant disturbance. A proportional multiple-integral-based state augmented Kalman filter is proposed to estimate and compensate for the time-varying disturbance that can be approximated as a polynomial function. The effectiveness of the proposed compound algorithm is demonstrated by comparative experiments on a gear-drive pointing system with a floating gear tension device, which shows a maximum 76% improvement in stabilization precision.

关键词： inertially stabilized platform     floating gear tension device     nonlinear friction     disturbance compensation     proportional multiple-integral observer    

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Preparation of ceria-zirconia solid solution with enhanced oxygen storage capacity and redox performance

Lijing MENG, Licheng LIU, Xuehong ZI, Hongxing DAI, Hong HE, Zhen ZHAO, Xinping WANG,

《环境科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 164-171 doi: 10.1007/s11783-010-0019-2

摘要： A new method called ultrasonic-assisted membrane reaction (UAMR) was reported for the fabrication of ceria-zirconia solid solution. A series of ceria-zirconia solid solutions with different Ce/Zr molar ratios were prepared by the UAMR method and characterized by X-ray diffraction (XRD), N adsorption, hydrogen temperature-programmed reduction (H-TPR), scanning electron microscope (SEM), and transmission electron microscopy (TEM) techniques. The UAMR method proved to be superior, especially when the Ce/Zr molar ratio was lower than 1, in fabricating ceria-zirconia solid solutions with large BET surface area, high oxygen storage capacity (OSC), and low reduction temperature.

关键词： membrane reaction     ceria-zirconia     Ce/Zr molar ratio     solid solution     hydrogen temperature-programmed reduction (H2-TPR)    

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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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Characteristics of the stabilized/solidified municipal solid wastes incineration fly ash and the leaching

Yan SHAO,Haobo HOU,Guangxing WANG,Sha WAN,Min ZHOU

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 192-200 doi: 10.1007/s11783-014-0719-0

摘要： Fly ash is a hazardous byproduct of municipal solid wastes incineration (MSWI). An alkali activated blast furnace slag-based cementitious material was used to stabilize/solidify the fly ash at experimental level. The characteristics of the stabilized/solidified fly ash, including metal leachability, mineralogical characteristics and the distributions of metals in matrices, were tested by toxic characteristic leaching procedure (TCLP), X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) respectively. Continuous acid extraction was utilized to extract metal ions and characterize their leaching behavior. The stabilization/solidification procedure for MSWI fly ash demonstrates a strong fixing capacity for the metals by the formation of C-S-H phase, hydrated calcium aluminosilicate and ettringite. The stabilized/solidified fly ash shows a dense and homogeneous microstructure. Cr is mainly solidified in hydrated calcium aluminosilicate, C-S-H and ettringite phase through physical encapsulation, precipitation, adsorption or substitution mechanisms, and Pb is mainly solidified in C-S-H phase and absorbed in the Si-O structure.

关键词： municipal solid waste incineration (MSWI) fly ash     blast furnace slag     leaching behavior     Cr     Pb    

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Remediation of soil and groundwater contaminated with organic chemicals using stabilized nanoparticles

Zhengqing Cai, Xiao Zhao, Jun Duan, Dongye Zhao, Zhi Dang, Zhang Lin

《环境科学与工程前沿（英文）》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1263-8

摘要： Abstract ▪ Overviewed evolution and environmental applications of stabilized nanoparticles. ▪ Reviewed theories on particle stabilization for enhanced reactivity/deliverability. ▪ Examined various in situ remediation technologies based on stabilized nanoparticles. ▪ Summarized knowledge on transport of stabilized nanoparticles in porous media. ▪ Identified key knowledge gaps and future research needs on stabilized nanoparticles. Due to improved soil deliverability and high reactivity, stabilized nanoparticles have been studied for nearly two decades for in situ remediation of soil and groundwater contaminated with organic pollutants. While large amounts of bench- and field-scale experimental data have demonstrated the potential of the innovative technology, extensive research results have also unveiled various merits and constraints associated different soil characteristics, types of nanoparticles and particle stabilization techniques. Overall, this work aims to critically overview the fundamental principles on particle stabilization, and the evolution and some recent developments of stabilized nanoparticles for degradation of organic contaminants in soil and groundwater. The specific objectives are to: 1) overview fundamental mechanisms in nanoparticle stabilization; 2) summarize key applications of stabilized nanoparticles for in situ remediation of soil and groundwater contaminated by legacy and emerging organic chemicals; 3) update the latest knowledge on the transport and fate of stabilized nanoparticles; 4) examine the merits and constraints of stabilized nanoparticles in environmental remediation applications; and 5) identify the knowledge gaps and future research needs pertaining to stabilized nanoparticles for remediation of contaminated soil and groundwater. Per instructions of this invited special issue, this review is focused on contributions from our group (one of the pioneers in the subject field), which, however, is supplemented by important relevant works by others. The knowledge gained is expected to further advance the science and technology in the environmental applications of stabilized nanoparticles.

关键词： Stabilized nanoparticle     In-situ remediation     Organic contaminant     Soil remediation     Groundwater     Fate and transport    

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Effect of polymer structures on electro-optical properties of polymer stabilized liquid crystal films

WANG Shoulian, HE Jie, ZENG Yu, YAN Bin, WANG Yinghan

《化学科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 265-268 doi: 10.1007/s11705-008-0054-8

摘要： The polymer stabilized liquid crystal (PSLC) film is a relatively novel electro-optical material, which is generally obtained by dissolving a small amount of a bifunctional photoreactive monomer in a low molecular mass liquid crystal. In this paper, the PSLC films were prepared with photoreactive biphenyl methacrylate monomers by photopolymerization induced phase separation. The effects of liquid crystal concentration, curing time, monomer structures and alignment layer on the electro-optical properties of PSLC films were investigated. The results show that the transmittance in the OFF state () increased with the liquid crystal concentration, but the driving voltage decreased. was also influenced by the curing time. Furthermore, when polyimide was used as alignment layer, the films prepared from the bifunctional monomer shows a higher T, while those from the single functional monomer exhibited a deformed electro-optical curve due to the unsteady polymer networks.
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Structural characteristics of cement-stabilized soil bases with 3D finite element method

Yunfeng PENG, Yunlong HE,

《结构与土木工程前沿（英文）》 2009年 第3卷 第4期   页码 428-434 doi: 10.1007/s11709-009-0059-5

摘要： Cement-stabilized soil bases have been widely used in expressways due to its high strength, appropriate stiffness, good water resistance, and frost resistance. So far, the structural characteristics and mechanical behaviors of cement-stabilized soil bases were not investigated so much. In this paper, the 3D elastic-plastic finite element method (FEM) was used to analyze the mechanical behaviors and structural characteristics of cement-stabilized soil bases from construction to operation. The pavement filling and the traffic loading processes were simulated, and a contact model was used to simulate the contact behavior between each layer of the pavement. Considering the construction process, the structural characteristics and mechanical behaviors of cement-stabilized soil bases were studied under asphalt-concrete pavement conditions. Furthermore, the general rules of deformations and stresses in cement-stabilized soil bases under different conditions were discussed, and some suggestions were put forward for the design and construction of cement-stabilized soil bases.

关键词： different     strength     asphalt-concrete pavement     FEM     appropriate stiffness    

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Unconfined compressive strength prediction of soils stabilized using artificial neural networks and support

Alireza TABARSA, Nima LATIFI, Abdolreza OSOULI, Younes BAGHERI

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 520-536 doi: 10.1007/s11709-021-0689-9

摘要： This study aims to improve the unconfined compressive strength of soils using additives as well as by predicting the strength behavior of stabilized soils using two artificial-intelligence-based models. The soils used in this study are stabilized using various combinations of cement, lime, and rice husk ash. To predict the results of unconfined compressive strength tests conducted on soils, a comprehensive laboratory dataset comprising 137 soil specimens treated with different combinations of cement, lime, and rice husk ash is used. Two artificial-intelligence-based models including artificial neural networks and support vector machines are used comparatively to predict the strength characteristics of soils treated with cement, lime, and rice husk ash under different conditions. The suggested models predicted the unconfined compressive strength of soils accurately and can be introduced as reliable predictive models in geotechnical engineering. This study demonstrates the better performance of support vector machines in predicting the strength of the investigated soils compared with artificial neural networks. The type of kernel function used in support vector machine models contributed positively to the performance of the proposed models. Moreover, based on sensitivity analysis results, it is discovered that cement and lime contents impose more prominent effects on the unconfined compressive strength values of the investigated soils compared with the other parameters.

关键词： unconfined compressive strength     artificial neural network     support vector machine     predictive models     regression    

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标题 作者 时间 类型 操作

Brazing of ceramic-to-ceramic and ceramic-to-metal joints in air

Kirsten BOBZIN, Thomas SCHLAEFER, Lidong ZHAO, Nils KOPP, Arne SCHLEGEL

期刊论文

Preparation and characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball milling

Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA

期刊论文

Selective conversion of cellulose to hexitols over bi-functional Ru-supported sulfated zirconia and silica-zirconia

Zhiqiang Song,Hua Wang,Yufei Niu,Xiao Liu,Jinyu Han

期刊论文

Mechanical properties of stabilized artificial organic soil

XU Riqing, GUO Yin, LIU Zengyong

期刊论文

Effect of alumina and zirconia as binders on the activity of Fe-BEA for NH

Jin Shi, Zihao Zhang, Mingxia Chen, Zhixiang Zhang, Wenfeng Shangguan, Shunchao Gu, Hirano Shin-ichi

期刊论文

total oxidizable carbon, phosphate and various metallic ions from HO solution with amino-functionalized zirconia

期刊论文

Biopolymer-stabilized emulsions on the basis of interactions between β -lactoglobulin and ι -carrageenan

Qiaomei RU, Younghee CHO, Qingrong HUANG,

期刊论文

High-precision gyro-stabilized control of a gear-driven platform with a floating gear tension device

期刊论文

Preparation of ceria-zirconia solid solution with enhanced oxygen storage capacity and redox performance

Lijing MENG, Licheng LIU, Xuehong ZI, Hongxing DAI, Hong HE, Zhen ZHAO, Xinping WANG,

期刊论文

Polysulfone and zirconia composite separators for alkaline water electrolysis

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

期刊论文

Characteristics of the stabilized/solidified municipal solid wastes incineration fly ash and the leaching

Yan SHAO,Haobo HOU,Guangxing WANG,Sha WAN,Min ZHOU

期刊论文

Remediation of soil and groundwater contaminated with organic chemicals using stabilized nanoparticles

Zhengqing Cai, Xiao Zhao, Jun Duan, Dongye Zhao, Zhi Dang, Zhang Lin

期刊论文

Effect of polymer structures on electro-optical properties of polymer stabilized liquid crystal films

WANG Shoulian, HE Jie, ZENG Yu, YAN Bin, WANG Yinghan

期刊论文

Structural characteristics of cement-stabilized soil bases with 3D finite element method

Yunfeng PENG, Yunlong HE,

期刊论文

Unconfined compressive strength prediction of soils stabilized using artificial neural networks and support

Alireza TABARSA, Nima LATIFI, Abdolreza OSOULI, Younes BAGHERI

期刊论文