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CeO doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-022-1539-2

摘要:

• CeO2 doping significantly improved low-temperature NH3-SCR activity on FeTiOx.

关键词: NH3-SCR     CeO2 doping     Low-temperature NOx removal     Improved redox property     In situ XAFS analysis    

Thermodynamic analysis of liquid phase in situ hydrogenation of glycerol for 1,3-propanediol synthesis

Kun OUYANG, Yu HUANG, Haoyi CHEN, Tao LI, Fahai CAO, Dingye FANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 67-73 doi: 10.1007/s11705-010-0541-6

摘要: Based on the combination of the glycerol aqueous-phase reforming (APR) and catalytic hydrogenation of glycerol, a novel reaction system of liquid phase in situ hydrogenation of glycerol for the synthesis of 1,3-propanediol is proposed, in which hydrogen is produced from glycerol aqueous-phase reforming in the same reactor. In this new system, the glycerol is the raw material of the aqueous-phase reforming reaction; the hydrogen generated from the APR of glycerol can be quickly transformed to the in situ hydrogenation of glycerol to produce 1,3-propanediol, which can improve the selectivity of hydrogen for the APR process of glycerol. Moreover, thermodynamic calculation of the coupling processes was carried out, and standard molar enthalpies and equilibrium constants of foregoing reactions were obtained. The above calculation results indicate that the combination process is feasible for 1,3-propanediol synthesis.

关键词: glycerol     aqueous-phase reforming     1     3-propanediol     in-situ reduction    

Development and application of ex-situ presulfurization technology for hydrotreating catalysts in China

Yulan GAO, Xiangchen FANG, Zhenmin CHENG

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 287-296 doi: 10.1007/s11705-010-0529-2

摘要: The development and application of ex-situ presulfurization (EPRES) technology for hydrotreating catalysts has been reviewed in the present article. The studies in laboratory scale and commercial practice indicated that the adoption of the EPRES catalyst in industrial application can significantly enhance the degree of presulfurization of metal oxide components, shorten the start-up period, and effectively reduce the environmental impact as well as the danger of start-up procedure in industrial hydrotreating unit. This catalyst has been proved to be versatile for different types of hydrogenation reactions. Different types of active site models are also discussed for better understanding the nature of presulfurized catalysts.

关键词: ex-situ presulfurization     in situ presulfurization     hydrotreating catalyst     sulfur utilization ratio    

Polyolefin-nanocomposites with special properties by in-situ polymerization

Walter Kaminsky

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 555-563 doi: 10.1007/s11705-018-1715-x

摘要:

Exceptionally strong polyolefin nanocomposites are synthesized by in-situ polymerization using soluble metallocene/methylaluminoxane (MAO) as catalysts in a two-step process. First, the soluble metallocene/MAO or other single site catalysts are absorbed on the surface of the nanofillers. Then by addition of ethene or propene, a polyolefin film is formed, covering the nanoparticles, layered silicates, or fibers. The resulting polyethylene and polypropylene nanocomposites are characterized by better physical and chemical properties such as stiffness, gas barrier properties, degradation temperatures, and crystallization rates. They show better mechanical properties than materials produced by mechanical blending. The thickness of the polyolefin can be controlled by the pressure of ethene or propene and by the polymerization time. Carbon fibers and carbon nanotubes are covered with isotactic or syndiotactic polypropylene. Because of the hydrophobic character of the carbon surface, the polymer is drawn on the fiber. This leads to a reinforced combined polymer with special properties. The crystallization temperature is 10 °C higher and therefore the crystallization rate up to 20 times faster than that of pure syndiotactic polypropylene. The form stability increases by 100% if 3 wt-% of carbon nanotubes are incorporated.

关键词: polyolefin nanocomposites     metallocenes     methylaluminoxane    

DX桩群桩承载性状的数值分析

张清林,陈立宏

《中国工程科学》 2012年 第14卷 第1期   页码 51-59

摘要:

通过数值计算对不同桩间距的DX桩群桩进行了分析研究。结果表明:DX桩的群桩效应随着桩间距的减小而逐渐明显,间距为6倍桩径的群桩极限承载力是间距为3倍桩径的群桩极限承载力的1.32倍;群桩间距由3倍桩径增大为6倍桩径时,群桩效应系数由0.59增大为0.78;群桩间土体沉降的最大值发生在两扩盘中间位置处,且随着桩间距的增大而减小。

关键词: DX桩     群桩     沉降     数值分析    

DX旋挖挤扩灌注桩单桩抗拔承载性状的数值分析

陈立宏,张清林,袁希雨

《中国工程科学》 2012年 第14卷 第1期   页码 31-36

摘要:

总结了DX桩的抗拔研究现状,采用FLAC3D对具有两个承力盘的DX单桩和相同直径与长度的普通直孔桩做了抗拔的数值计算分析,对DX单桩抗拔的性状进行了研究。模型参数依据土工试验获取并采用现场大比尺试验结果进行校验。通过模拟分级加载,得到了DX桩和直孔桩的抗拔承载力曲线,同时得到了沿桩身的轴力分布,依据这些计算结果展开分析,可以发现DX单桩的抗拔承载力比相同直径的普通直孔桩高出一倍以上,其上下承力盘的发挥作用是由上而下,但当荷载增大到一定程度时,下盘将发挥更大的作用。

关键词: DX桩     抗拔     数值分析    

Propagation characteristics of transient waves in low-strain integrity testing on cast-in-situ concrete

Hanlong LIU, Xuanming DING

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 240-240 doi: 10.1007/s11709-009-0100-8

In situ-based assessment of soil liquefaction potential–Case study of an earth dam in Tunisia

Ikram GUETTAYA,Mohamed Ridha EL OUNI

《结构与土木工程前沿(英文)》 2014年 第8卷 第4期   页码 456-461 doi: 10.1007/s11709-014-0259-5

摘要: The present paper examines the evaluation of liquefaction potential of an earth dam foundation in Tunisia. The assessment of soil liquefaction was made using deterministic and probabilistic simplified procedures developed from several case histories. The data collected from the field investigation performed before and after the vibrocompaction are analyzed and the results are reported. The obtained results show that after vibrocompaction, a significant improvement of the soil resistance reduces the liquefaction potential of the sandy foundation. Indeed, in the untreated layers, the factor of safety drops below 1 which means that the soil is susceptible for liquefaction. However, in the compacted horizons, the values of exceed the unit which justifies the absence of liquefaction hazard of the foundation.

关键词: liquefaction     cone penetration test (CPT)     standard penetration test (SPT)     vibrcompaction     sand    

In situ synthesis of FeS/Carbon fibers for the effective removal of Cr(VI) in aqueous solution

Rongrong Zhang, Daohao Li, Jin Sun, Yuqian Cui, Yuanyuan Sun

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1247-8

摘要: Abstract • FeS/carbon fibers were in situ synthesized with Fe-carrageenan hydrogel fiber. • The double helix structure of carrageenan is used to load and disperse Fe. • Pyrolyzing sulfate groups enriched carrageenan-Fe could easily generate FeS. • The adsorption mechanisms include reduction and complexation reaction. Iron sulfide (FeS) nanoparticles (termed FSNs) have attracted much attention for the removal of pollutants due to their high efficiency and low cost, and because they are environmentally friendly. However, issues of agglomeration, transformation, and the loss of active components limit their application. Therefore, this study investigates in situ synthesized FeS/carbon fibers with an Fe-carrageenan biomass as a precursor and nontoxic sulfur source to ascertain the removal efficiency of the fibers. The enrichment of sulfate groups as well as the double-helix structure in ι-carrageenan-Fe could effectively avoid the aggregation and loss of FSNs in practical applications. The obtained FeS/carbon fibers were used to control a Cr(VI) polluted solution, and exhibited a relatively high removal capacity (81.62 mg/g). The main mechanisms included the reduction of FeS, electrostatic adsorption of carbon fibers, and Cr(III)-Fe(III) complexation reaction. The pseudo-second-order kinetic model and Langmuir adsorption model both provided a good fit of the reaction process; hence, the removal process was mainly controlled by chemical adsorption, specifically monolayer adsorption on a uniform surface. Furthermore, co-existing anions, column, and regeneration experiments indicated that the FeS/carbon fibers are a promising remediation material for practical application.

关键词: Carrageenan     FeS     Double-helix structure     Hexavalent chromium    

In-situ condition monitoring of reinforced concrete structures

Sanjeev Kumar VERMA,Sudhir Singh BHADAURIA,Saleem AKHTAR

《结构与土木工程前沿(英文)》 2016年 第10卷 第4期   页码 420-437 doi: 10.1007/s11709-016-0336-z

摘要: Performance of concrete structures is significantly influenced and governed by its durability and resistance to environmental or exposure conditions, apart from its physical strength. It can be monitored, evaluated and predicted through modeling of physical deterioration mechanisms, performance characteristics and parameters and condition monitoring of in situ concrete structures. One such study has been conducted using Non-destructive testing equipment in the city of Bhopal and around located in India. Some selected parameters influencing durability of reinforced concrete (RC) structures such as concrete cover, carbonation depth, chloride concentration, half cell potential and compressive strength have been measured, for establishing correlation among various parameters and age of structures. Effects of concrete cover and compressive strength over the variation of chloride content with time are also investigated.

关键词: concrete     carbonation     chloride     corrosion     monitoring     models    

光学成像中的相位问题 Review

Guo-hai SITU, Hai-chao WANG

《信息与电子工程前沿(英文)》 2017年 第18卷 第9期   页码 1277-1287 doi: 10.1631/FITEE.1700298

摘要: 相比于振幅,相位包含更多光场信息。因此,在现代科学和工程学的许多分支中更鼓励测量光场的相位。然而,对可见光波段电磁波而言,直接测量相位非常困难,必须使用计算方法从捕获的光强度中计算相位。本文回顾了近期我们在迭代相位恢复技术及其在光学成像中的应用等方面的研究工作。

关键词: 相位恢复;相位成像;计算成像;Gerchberg-Saxton算法;光学加密;计算机全息图    

In situ enhanced bioremediation of dichlorvos by a phyllosphere

Jiying NING, Gang GANG, Zhihui BAI, Qing HU, Hongyan QI, Anzhou MA, Xuliang ZHUAN, Guoqiang ZHUANG

《环境科学与工程前沿(英文)》 2012年 第6卷 第2期   页码 231-237 doi: 10.1007/s11783-011-0316-4

摘要: A bacterium capable of degrading dichlorvos was isolated from the rape phyllosphere and designated YD4. The strain was identified as sp., based on its phenotypic features and 16S rRNA gene sequence. Strain YD4 was able to utilize dichlorvos as the sole source of phosphorus. enhanced bioremediation of dichlorvos by YD4 was hereafter studied. Chlorpyrifos and phoxim could also be degraded by this strain as the sole phosphorus source. A higher degradation rate of dichlorvos was observed after spraying YD4 onto the surface of rape leaves when compared to the sterilized-YD4 and water-treated samples. The results indicated that pesticide-degrading epiphytic bacterium could become a new way for phyllosphere bioremediation where the hostile niche is unsuitable for other pesticide-degrading bacteria isolated from soil and water.

关键词: enhanced bioremediation     organophosphorus pesticides     phyllosphere     Flavobacterium sp.    

Investigate of in situ sludge reduction in sequencing batch biofilm reactor: Performances, mechanisms

Yonglei Wang, Baozhen Liu, Kefeng Zhang, Yongjian Liu, Xuexin Xu, Junqi Jia

《环境科学与工程前沿(英文)》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1077-0

摘要:

Microbial metabolism uncoupling, sludge decay is the main mechanism to promote in situ sludge reduction on this biofilm system.

The main reduction mechanism inside the biofilm is sludge decay in the longitudinal distribution of biofilm.

Mizugakiibacter and Azospira anaerobic fermentation bacterium dominate the FSC organisms indicating the dominant mechanism on the biofilm is sludge decay.

The floating spherical carriers with compound of the polyurethane and two fiber balls can effectively blocking suspended sludge, improving Biofilm formation efficiency significantly.

关键词: In situ sludge reduction     Biofilm     Composite floating spherical carriers     Microbial community     SBBR    

Development of an H reduction and moderate oxidation method for 3,5-dimethylpyridine hydrogenation in trickle bed reactor

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1807-1817 doi: 10.1007/s11705-022-2243-2

摘要: The Ru/C catalyst prepared by impregnation method was used for hydrogenation of 3,5-dimethylpyridine in a trickle bed reactor. Under the same reduction conditions (300 °C in H2), the catalytic activity of the non-in-situ reduced Ru/C-n catalyst was higher than that of the in-situ reduced Ru/C-y catalyst. Therefore, an in-situ H2 reduction and moderate oxidation method was developed to increase the catalyst activity. Moreover, the influence of oxidation temperature on the developed method was investigated. The catalysts were characterized by Brunauer–Emmett–Teller method, hydrogen temperature programmed reduction H2-TPR, hydrogen temperature-programmed dispersion (H2-TPD), X-ray diffraction, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, O2 chemisorption and oxygen temperature-programmed dispersion (O2-TPD) analyses. The results showed that there existed an optimal Ru/RuOx ratio for the catalyst, and the highest 3,5-dimethylpyridine conversion was obtained for the Ru/C-i1 catalyst prepared by in-situ H2 reduction and moderate oxidation (oxidized at 100 °C). Excessive oxidation (200 °C) resulted in a significant decrease in the Ru/RuOx ratio of the in-situ H2 reduction and moderate oxidized Ru/C-i2 catalyst, the interaction between RuOx species and the support changed, and the hard-to-reduce RuOx species was formed, leading to a significant decrease in catalyst activity. The developed in-situ H2 reduction and moderate oxidation method eliminated the step of the non-in-situ reduction of catalyst outside the trickle bed reactor.

关键词: Ru/C catalyst     in-situ H2 reduction and moderate oxidation     in-situ reduction     non-in-situ reduction     hydrogenation of 3     5-dimethylpyridine    

Tracing the impact of stack configuration on interface resistances in reverse electrodialysis by in situ

《环境科学与工程前沿(英文)》 2022年 第16卷 第4期 doi: 10.1007/s11783-021-1480-9

摘要:

• RED performance and stack resistance were studied by EIS and LSV.

关键词: Reverse electrodialysis     Electrochemical impedance spectroscopy     Concentration polarization     Spacer shadow effect    

标题 作者 时间 类型 操作

CeO doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction

期刊论文

Thermodynamic analysis of liquid phase in situ hydrogenation of glycerol for 1,3-propanediol synthesis

Kun OUYANG, Yu HUANG, Haoyi CHEN, Tao LI, Fahai CAO, Dingye FANG

期刊论文

Development and application of ex-situ presulfurization technology for hydrotreating catalysts in China

Yulan GAO, Xiangchen FANG, Zhenmin CHENG

期刊论文

Polyolefin-nanocomposites with special properties by in-situ polymerization

Walter Kaminsky

期刊论文

DX桩群桩承载性状的数值分析

张清林,陈立宏

期刊论文

DX旋挖挤扩灌注桩单桩抗拔承载性状的数值分析

陈立宏,张清林,袁希雨

期刊论文

Propagation characteristics of transient waves in low-strain integrity testing on cast-in-situ concrete

Hanlong LIU, Xuanming DING

期刊论文

In situ-based assessment of soil liquefaction potential–Case study of an earth dam in Tunisia

Ikram GUETTAYA,Mohamed Ridha EL OUNI

期刊论文

In situ synthesis of FeS/Carbon fibers for the effective removal of Cr(VI) in aqueous solution

Rongrong Zhang, Daohao Li, Jin Sun, Yuqian Cui, Yuanyuan Sun

期刊论文

In-situ condition monitoring of reinforced concrete structures

Sanjeev Kumar VERMA,Sudhir Singh BHADAURIA,Saleem AKHTAR

期刊论文

光学成像中的相位问题

Guo-hai SITU, Hai-chao WANG

期刊论文

In situ enhanced bioremediation of dichlorvos by a phyllosphere

Jiying NING, Gang GANG, Zhihui BAI, Qing HU, Hongyan QI, Anzhou MA, Xuliang ZHUAN, Guoqiang ZHUANG

期刊论文

Investigate of in situ sludge reduction in sequencing batch biofilm reactor: Performances, mechanisms

Yonglei Wang, Baozhen Liu, Kefeng Zhang, Yongjian Liu, Xuexin Xu, Junqi Jia

期刊论文

Development of an H reduction and moderate oxidation method for 3,5-dimethylpyridine hydrogenation in trickle bed reactor

期刊论文

Tracing the impact of stack configuration on interface resistances in reverse electrodialysis by in situ

期刊论文