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Catalytic performance of Co-Mo-Ce-K/γ-Al

Yuqiong ZHAO, Yongfa ZHANG

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 457-460 doi: 10.1007/s11705-010-0524-7

摘要： The catalytic performance of Co-Mo-Ce-K/γ-Al O catalyst for the shift reaction of CO in coke oven gas is investigated using X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The results indicate that Ce and K have a synergistic effect on promoting the catalytic activity, and the Co-Mo-Ce-K/γ-Al O catalyst with 3.0 wt-% CeO and 6.0 wt-% K O exhibits the highest activity. CeO favors Co dispersion and mainly produces an electronic effect. TPR characterization results indicate that the addition of CeO -K O in the Co-Mo-Ce-K/γ-Al O catalyst decreases the reduction temperature of active components, and part of octahedrally coordinated Mo transforms into tetrahedrally coordinated Mo , which has a close relationship with the catalytic activity.

关键词： coke oven gas     water gas shift reaction     sulfur-tolerant catalyst     cerium dioxide    

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Denitrification performance and sulfur resistance mechanism of Sm–Mn catalyst for low temperature NH-SCR

《化学科学与工程前沿（英文）》 2023年 第17卷 第5期   页码 617-633 doi: 10.1007/s11705-022-2258-8

摘要： MnOx and Sm–Mn catalysts were prepared with the coprecipitation method, and they showed excellent activities and sulfur resistances for the selective catalytic reduction of NOx by NH3 between 50 and 300 °C in the presence of excess oxygen. 0.10Sm–Mn catalyst indicated better catalytic activity and sulfur resistance. Additionally, the Sm doping led to multi-aspect impacts on the phases, morphology structures, gas adsorption, reactions process, and specific surface areas. Therefore, it significantly enhances the NO conversion, N2 selectivity, and sulfur resistance. Based on various experimental characterization results, the reaction mechanism of catalysts and the effect of SO2 on the reaction process about the catalysts were extensively explored. For 0.10Sm–Mn catalyst, manganese sulfate and sulfur ammonium cannot be generated broadly under the influence of SO2 and the amount of surface adsorbed oxygen. The Bronsted acid sites strengthen significantly due to the addition of SO2, enhancing the sulfur resistance of the 0.10Sm–Mn catalyst.

关键词： MnOx     Sm–Mn     catalyst     NH3-SCR     sulfur resistance    

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Influence of HS and NH on biogas dry reforming using Ni catalyst: a study on single and synergetic effect

《环境科学与工程前沿（英文）》 2023年 第17卷 第3期 doi: 10.1007/s11783-023-1632-1

摘要：

● NH3 in biogas had a slight inhibitory effect on dry reforming.

关键词： Biogas     Dry reforming     Sulfur poisoning     Ammonia     Synergetic effect     Hydrogen    

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Fault tolerant control strategy for modular PWM current source inverter

《能源前沿（英文）》 2023年 第17卷 第2期   页码 228-238 doi: 10.1007/s11708-022-0852-6

摘要： In this paper, a fault-tolerant control method for an input-series output-parallel modular grid-tied pulse-width modulation (PWM) current source inverter is proposed to address the most commonly seen single symmetrical gate-commutated thyristor (SGCT) open-circuit fault problems. This method actively offsets the neutral point of the current space vector to ensure a sinusoidal output of the grid current, and it can achieve the upper limit power of the inverter under the condition of a single SGCT open-circuit fault. In addition, an active damping control method based on grid harmonic current feedback is proposed after analyzing the influence of the transformer ferromagnetic resonance caused by the neutral point offset on the power quality of the grid current. It has been demonstrated that the proposed method effectively suppresses the resonance caused by the transformer and the modified modulation, improving the grid current’s power quality.

关键词： current source converter (CSC)     fault-tolerant control     space vector modulation     active damping     resonance suppression     power quality    

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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    

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amino-functionalized University of Oslo 66 membranes as efficacious polysulfide barriers for lithium−sulfur

《化学科学与工程前沿（英文）》 2023年 第17卷 第2期   页码 194-205 doi: 10.1007/s11705-022-2206-7

摘要： The shuttle effect of soluble polysulfides is a serious problem impeding the development of lithium−sulfur batteries. Herein, continuous amino-functionalized University of Oslo 66 membranes supported on carbon nanotube films are proposed as ion-permselective interlayers that overcome these issues and show outstanding suppression of the polysulfide shuttle effect. The proposed membrane material has appropriately sized pores, and can act as ionic sieves and serve as barriers to polysulfides transport while allowing the passage of lithium ions during electrochemical cycles, thereby validly preventing the shuttling of polysulfides. Moreover, a fast catalytic conversion of polysulfides is also achieved with the as-developed interlayer. Therefore, lithium−sulfur batteries with this interlayer show a desirable initial capacity of 999.21 mAh·g–1 at 1 C and a durable cyclic stability with a decay rate of only 0.04% per cycle over 300 cycles. Moreover, a high area capacity of 4.82 mAh·cm–2 is also obtained even under increased sulfur loading (5.12 mg·cm–2) and a lean-electrolyte condition (E/S = 4.8 μL·mg–1).

关键词： lithium−sulfur batteries     amino-functionalized University of Oslo 66 membrane     polysulfide     interlayer    

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Tuning nitrogen defects and doping sulfur in carbon nitride for enhanced visible light photocatalytic

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 93-101 doi: 10.1007/s11705-022-2175-x

摘要： Defect construction and heteroatom doping are effective strategies for improving photocatalytic activity of carbon nitride (g-C3N4). In this work, N defects were successfully prepared via cold plasma. High-energy electrons generated by plasma can produce N defects and embed sulfur atoms into g-C3N4. The N defects obviously promoted photocatalytic degradation performance that was 7.5 times higher than that of pure g-C3N4. The concentration of N defects can be tuned by different power and time of plasma. With the increase in N defects, the photocatalytic activity showed a volcanic trend. The g-C3N4 with moderate concentration of N defects exhibited the highest photocatalytic activity. S-doped g-C3N4 exhibited 11.25 times higher photocatalytic activity than pure g-C3N4. It provided extra active sites for photocatalytic reaction and improved stability of N defects. The N vacancy-enriched and S-doped g-C3N4 are beneficial for widening absorption edge and improving the separation efficiency of electron and holes.

关键词： g-C3N4     nitrogen defect     sulfur doping     photodegradation     plasma    

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Machinability of damage-tolerant titanium alloy in orthogonal turn-milling

Tao SUN, Lufang QIN, Junming HOU, Yucan FU

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 504-515 doi: 10.1007/s11465-020-0586-2

摘要： The damage-tolerant titanium alloy TC21 is used extensively in important parts of advanced aircraft because of its high strength and durability. However, cutting TC21 entails problems, such as high cutting temperature, high tool tip stress, rapid tool wear, and difficulty guaranteeing processing quality. Orthogonal turn-milling can be used to solve these problems. In this study, the machinability of TC21 in orthogonal turn-milling is investigated experimentally to optimize the cutting parameters of orthogonal turn-milling and improve the machining efficiency, tool life, and machining quality of TC21. The mechanism of the effect of turn-milling parameters on tool life is discussed, the relationship between each parameter and tool life is analyzed, and the failure process of a TiAlN-coated tool in turn-milling is explored. Experiments are conducted on the integrity of the machined surface (surface roughness, metallographic structure, and work hardening) by turn-milling, and how the parameters influence such integrity is analyzed. Then, reasonable cutting parameters for TC21 in orthogonal turn-milling are recommended. This study provides strong guidance for exploring the machinability of difficult-to-cut-materials in orthogonal turn-milling and improves the applicability of orthogonal turn-milling for such materials.

关键词： orthogonal turn-milling     damage-tolerant titanium alloy     tool life and failure     machined surface integrity     machinability    

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Response of indigenous Cd-tolerant electrochemically active bacteria in MECs toward exotic Cr(VI) based

Xia Hou, Liping Huang, Peng Zhou, Hua Xue, Ning Li

《环境科学与工程前沿（英文）》 2018年 第12卷 第4期 doi: 10.1007/s11783-018-1057-4

摘要：

Cell membrane of indigenous Cd-tolerant EAB harbored more cadmium than chromium.

Indigenous Cd-tolerant EAB cytoplasm located more chromium than cadmium.

Simultaneously quantitatively imaging Cd(II) and Cr(III) ions in EAB was achieved.

Current accelerated the harboring of cadmium in EAB at an initial 2 h.

Current directed the accumulation of more chromium in EAB over time.

关键词： Microbial electrolysis cell     Electrochemically active bacteria     Cd-tolerant bacteria     Cd(II) and Cr(VI)     Fluorescence probe    

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Theoretical study on the mechanism of sulfur migration to gas in the pyrolysis of benzothiophene

《化学科学与工程前沿（英文）》 2023年 第17卷 第3期   页码 334-346 doi: 10.1007/s11705-022-2209-4

摘要： The release and control of sulfur species in the pyrolysis of fossil fuels and solid wastes have attracted attention worldwide. Particularly, thiophene derivatives are important intermediates for the sulfur gas release from organic sulfur, but the underlying migration mechanisms remain unclear. Herein, the mechanism of sulfur migration during the release of sulfur-containing radicals in benzothiophene pyrolysis was explored through quantum chemistry modeling. The C1-to-C2 H-transfer has the lowest energy barrier of 269.9 kJ·mol–1 and the highest rate constant at low temperatures, while the elevated temperature is beneficial for C−S bond homolysis. 2-Ethynylbenzenethiol is the key intermediate for the formation of S and SH radicals with the overall energy barriers of 408.0 and 498.7 kJ·mol–1 in favorable pathways. The generation of CS radicals is relatively difficult because of the high energy barrier (551.8 kJ·mol–1). However, it can be significantly promoted by high temperatures, where the rate constant exceeds that for S radical generation above 930 °C. Consequently, the strong competitiveness of S and SH radicals results in abundant H2S during benzothiophene pyrolysis, and the high temperature is more beneficial for CS2 generation from CS radicals. This study lays a foundation for elucidating sulfur migration mechanisms and furthering the development of pyrolysis techniques.

关键词： benzothiophene     sulfur migration     pyrolysis     density functional theory    

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Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault tolerant

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 377-388 doi: 10.1007/s11465-017-0431-4

摘要：

Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method.

关键词： wind turbine nonlinear model     maximum power tracking     passive fault tolerant control     adaptive neural control    

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Kombucha SCOBY-based carbon and graphene oxide wrapped sulfur/polyacrylonitrile as a high-capacity cathodein lithium-sulfur batteries

Krishnaveni Kalaiappan, Subadevi Rengapillai, Sivakumar Marimuthu, Raja Murugan, Premkumar Thiru

《化学科学与工程前沿（英文）》 2020年 第14卷 第6期   页码 976-987 doi: 10.1007/s11705-019-1897-x

摘要： Hierarchically-porous carbon nano sheets were prepared as a conductive additive for sulfur/polyacrylonitrile (S/PAN) composite cathodes using a simple heat treatment. In this study, kombucha (that was derived from symbiotic culture of bacteria and yeast) carbon (KC) and graphene oxide (GO) were used as a carbon host matrix. These rational-designed S/PAN/KC/GO hybrid composites greatly suppress the diffusion of polysulfides by providing strong physical and chemical adsorption. The cathode delivered an initial discharge capacity of 1652 mAh·g at a 0.1 C rate and a 100 cycle capacity of 1193 mAh·g . The nano sheets with embedded hierarchical pores create a conductive network that provide effective electron transfer and fast electrochemical kinetics. Further, the nitrogen component of PAN can raise the affinity/interaction of the carbon host with lithium polysulfides, supporting the cyclic performance. The results exploit the cumulative contribution of both the conductive carbon matrix and PAN in the enhanced performance of the positive electrode.

关键词： sulfur cathode     kombucha SCOBY     graphene oxide     polyacrylonitrile     lithium-sulfur battery    

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zirconium-based metal-organic framework-801 films on carbon cloth as shuttle-inhibiting interlayers for lithium-sulfur

《化学科学与工程前沿（英文）》 2022年 第16卷 第4期   页码 511-522 doi: 10.1007/s11705-021-2068-4

摘要： Lithium-sulfur batteries have been regarded as the next-generation rechargeable batteries due to their high theoretical energy density and specific capacity. Nevertheless, the shuttle effect of lithium polysulfides has hindered the development of lithium-sulfur batteries. Herein, a novel zirconium-based metal-organic framework-801 film on carbon cloth was developed as a versatile interlayer for lithium-sulfur batteries. This interlayer has a hierarchical porous structure, suitable for the immobilization of lithium polysulfides and accommodating volume expansion on cycling. Moreover, the MOF-801 material is capable of strongly adsorbing lithium polysulfides and promoting their catalytic conversion, which can be enhanced by the abundant active sites provided by the continuous structure of the MOF-801 films. Based on the above advantages, the lithium-sulfur battery, with the proposed interlayer, delivers an initial discharge capacity of 927 mAh·g–1 at 1 C with an extremely low decay rate of 0.04% over 500 cycles. Additionally, a high area capacity of 4.3 mAh·cm–2 can be achieved under increased S loading.

关键词： lithium-sulfur batteries     metal-organic framework-801 film     interlayer     shuttle effect    

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Effects of sulfur on variations in the chemical speciation of heavy metals from fly ash glass

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1728-7

摘要：

● A higher sulfur content reduced the curing rate of Cr in glass.

关键词： Dechlorinated fly ash     SO3     Heavy metal     Chemical speciation     Glass solidification    

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自恢复容错系统的建模与分析

郭成昊,刘凤玉

《中国工程科学》 2007年 第9卷 第10期   页码 75-79

摘要：

容错系统不仅会产生硬件故障，由于连续长时间的运行，系统的性能也会逐渐下降或失效，即老化现象。综合考虑容错系统中的硬件故障和老化现象，提出了将传统的冗余技术和软件抗衰技术相结合的策略，并给出了该系统的非马尔可夫随机Petri网模型，随之对基于该模型的系统进行了定量分析。

关键词： 容错系统     软件抗衰     软件老化     冗余策略     非马尔可夫随机Petri网    

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标题 作者 时间 类型 操作

Catalytic performance of Co-Mo-Ce-K/γ-Al

Yuqiong ZHAO, Yongfa ZHANG

期刊论文

Denitrification performance and sulfur resistance mechanism of Sm–Mn catalyst for low temperature NH-SCR

期刊论文

Influence of HS and NH on biogas dry reforming using Ni catalyst: a study on single and synergetic effect

期刊论文

Fault tolerant control strategy for modular PWM current source inverter

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

amino-functionalized University of Oslo 66 membranes as efficacious polysulfide barriers for lithium−sulfur

期刊论文

Tuning nitrogen defects and doping sulfur in carbon nitride for enhanced visible light photocatalytic

期刊论文

Machinability of damage-tolerant titanium alloy in orthogonal turn-milling

Tao SUN, Lufang QIN, Junming HOU, Yucan FU

期刊论文

Response of indigenous Cd-tolerant electrochemically active bacteria in MECs toward exotic Cr(VI) based

Xia Hou, Liping Huang, Peng Zhou, Hua Xue, Ning Li

期刊论文

Theoretical study on the mechanism of sulfur migration to gas in the pyrolysis of benzothiophene

期刊论文

Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault tolerant

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

期刊论文

Kombucha SCOBY-based carbon and graphene oxide wrapped sulfur/polyacrylonitrile as a high-capacity cathodein lithium-sulfur batteries

Krishnaveni Kalaiappan, Subadevi Rengapillai, Sivakumar Marimuthu, Raja Murugan, Premkumar Thiru

期刊论文

zirconium-based metal-organic framework-801 films on carbon cloth as shuttle-inhibiting interlayers for lithium-sulfur

期刊论文

Effects of sulfur on variations in the chemical speciation of heavy metals from fly ash glass

期刊论文

自恢复容错系统的建模与分析

郭成昊,刘凤玉

期刊论文