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Encapsulation of polyethylene glycol in cellulose-based porous capsules for latent heat storage and light-to-thermalconversion

《化学科学与工程前沿(英文)》 2023年 第17卷 第8期   页码 1038-1050 doi: 10.1007/s11705-022-2279-3

摘要: Phase change materials are potential candidates for the application of latent heat storage. Herein, we fabricated porous capsules as shape-stable materials from cellulose-based polyelectrolyte complex, which were first prepared using cellulose 6-(N-pyridinium)hexanoyl ester as the cationic polyelectrolyte and carboxymethyl cellulose as the anionic polyelectrolyte to encapsulate polyethylene glycol by the vacuum impregnation method. Furthermore, the multi-walled carbon nanotube or graphene oxide, which were separately composited into the polyelectrolytes complex capsules to enhance thermal conductivity and light-to-thermal conversion efficiency. These capsules owned a typical core–shell structure, with an extremely high polyethylene glycol loading up to 34.33 g∙g‒1. After loading of polyethylene glycol, the resulted cellulose-based composite phase change materials exhibited high thermal energy storage ability with the latent heat up to 142.2 J∙g‒1, which was 98.5% of pure polyethylene glycol. Further results showed that the composite phase change materials demonstrated good form-stable property and thermal stability. Moreover, studies involving light-to-thermal conversion determined that composite phase change materials exhibited outstanding light-to-thermal conversion performance. Considering their exceptional comprehensive features, innovative composite phase change materials generated from cellulose presented a highly interesting choice for thermal management and renewable thermal energy storage.

关键词: cellulose     polyelectrolytes     phase change materials     thermal energy storage     light-to-thermal conversion    

Effect of Fe content on FeMn catalysts for light alkenes synthesis

ZHOU Jun, CHU Wei, ZHANG Hui, XU Huiyuan, ZHANG Tao

《化学科学与工程前沿(英文)》 2008年 第2卷 第3期   页码 315-318 doi: 10.1007/s11705-008-0050-z

摘要: The effect of Fe content on FeMn/MgO catalysts for light alkenes synthesis through CO hydrogenation was investigated. Catalysts were prepared by a conventional co-impregnation method, characterized using BET, X-ray powder diffraction (XRD) and Temperature-programmed reduction (H-TPR) techniques. High activity was obtained over the catalyst with 9 wt-% Fe content, over which CO conversion and the selectivity of C–C reached 91.36% and 58.48%, respectively. With the increase of Fe content, both the conversion and the selectivity were improved within a certain range and then decreased. The results show that the surface area of the catalyst played an important role in the catalytic reaction. With the increase of Fe loading, the interaction action between Fe and Mn was enhanced and FeMn solid solution was formed.

关键词: conventional co-impregnation     increase     conversion     loading     H-TPR    

Facile synthesis and enhanced visible-light photocatalytic activity of Ti

Xiaojie Zhang,Lei Wang,Shuqing Chen,Yi Huang,Zhuonan Song,Miao Yu

《化学科学与工程前沿(英文)》 2015年 第9卷 第3期   页码 349-358 doi: 10.1007/s11705-015-1523-5

摘要: Ti -doped TiO nanosheets with tunable phase composition (doped TiO (A/R)) were synthesized via a hydrothermal method with high surface area anatase TiO nanosheets TiO (A) as a substrate, structure directing agent, and inhibitor; the activity was evaluated using a probe reaction-photocatalytic CO conversion to methane under visible light irradiation with H as an electron donor and hydrogen source. High-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope, UV-Vis diffuse reflectance spectra, and X-ray diffraction (XRD) etc., were used to characterize the photocatalysts. XRD and HRTEM measurements confirmed the existence of anatase-rutile phase junction, while Ti and single-electron-trapped oxygen vacancy in the doped TiO (A/R) photocatalyst were revealed byelectron paramagnetic resonance (EPR) measurements. Effects of hydrothermal synthesis temperature and the amount of added anatase TiO on the photocatalytic activity were elucidated. Significantly enhanced photocatalytic activity of doped TiO (A/R) was observed; under the optimized synthesis conditions, CH generation rate of doped TiO (A/R) was 2.3 times that of Ti -doped rutile TiO .

关键词: Ti3+-doped TiO2     photocatalytic CO2 conversion     visible light irradiation    

From plasma to plasmonics: toward sustainable and clean water production through membranes

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 1809-1836 doi: 10.1007/s11705-023-2339-3

摘要: The increasing demand for potable water is never-ending. Freshwater resources are scarce and stress is accumulating on other alternatives. Therefore, new technologies and novel optimization methods are developed for the existing processes. Membrane-based processes are among the most efficient methods for water treatment. Yet, membranes suffer from severe operational problems, namely fouling and temperature polarization. These effects can harm the membrane’s permeability, permeate recovery, and lifetime. To mitigate such effects, membranes can be treated through two techniques: plasma treatment (a surface modification technique), and treatment through the use of plasmonic materials (surface and bulk modification). This article showcases plasma- and plasmonic-based treatments in the context of water desalination/purification. It aims to offer a comprehensive review of the current developments in membrane-based water treatment technologies along with suggested directions to enhance its overall efficiency through careful selection of material and system design. Moreover, basic guidelines and strategies are outlined on the different membrane modification techniques to evaluate its prerequisites. Besides, we discuss the challenges and future developments about these membrane modification methods.

关键词: water treatment     membrane-based process     plasma treatment     plasma polymerization     plasmonic     light-to-heat conversion    

Recent progress in MoS

Soheil RASHIDI, Akshay CARINGULA, Andy NGUYEN, Ijeoma OBI, Chioma OBI, Wei WEI

《能源前沿(英文)》 2019年 第13卷 第2期   页码 251-268 doi: 10.1007/s11708-019-0625-z

摘要: In an era of graphene-based nanomaterials as the most widely studied two-dimensional (2D) materials for enhanced performance of devices and systems in solar energy conversion applications, molybdenum disulfide (MoS ) stands out as a promising alternative 2D material with excellent properties. This review first examined various methods for MoS synthesis. It, then, summarized the unique structure and properties of MoS nanosheets. Finally, it presented the latest advances in the use of MoS nanosheets for important solar energy applications, including solar thermal water purification, photocatalytic process, and photoelectrocatalytic process.

关键词: 2D nanomaterial     molybdenum disulfide     solar energy conversion     solar thermal conversion     photocatalytst     photoelectrocatalyst    

Benzene conversion by manganese dioxide assisted silent discharge plasma

LU Bin, JI Min, YU Xin, FENG Tao, YAO Shuiliang

《环境科学与工程前沿(英文)》 2007年 第1卷 第4期   页码 477-481 doi: 10.1007/s11783-007-0076-3

摘要: Non-thermal plasma technologies have shown their promising potential specially for the low concentration of volatile organic compound control in indoor air in recent years. But it is also high energy consuming. So, to improve the en

关键词: consuming     Non-thermal     promising     volatile     compound    

Effect of temperature in the conversion of methanol to olefins (MTO) using an extruded SAPO-34 catalyst

Ignacio Jorge Castellanos-Beltran, Gnouyaro Palla Assima, Jean-Michel Lavoie

《化学科学与工程前沿(英文)》 2018年 第12卷 第2期   页码 226-238 doi: 10.1007/s11705-018-1709-8

摘要: The methanol-to-olefin (MTO) reaction was investigated in a bench-scale, fixed-bed reactor using an extruded catalyst composed of a commercial SAPO-34 (65 weight percentage, wt-%) embedded in an amorphous SiO matrix (35 wt-%). The texture properties, acidity and crystal structure of the pure SAPO-34 and its extruded form (E-SAPO-34) were analyzed and results indicated that the extrusion step did not affect the properties of the catalyst. Subsequently, E-SAPO-34 was tested in a temperature range between 300 and 500 °C, using an aqueous methanol mixture (80 wt-% water content) fed at a weight hour space velocity (WHSV) of 1.21 h . At 300 °C, a low conversion was observed combined with catalyst deactivation, which was ascribed to oligomerization and condensation reactions. The coke analysis showed the presence of diamandoid hydrocarbons, which are known to be inactive molecules in the MTO process. At higher temperatures, a quasi-steady state was reached during a 6 h reaction where the optimal temperature was identified at 450 °C, which incidentally led to the lowest coke deposition combined with the highest H/C ratio. Above 450 °C, surges of ethylene and methane were associated to a combination of H-transfer and protolytic cracking reactions. Finally, the present work underscored the convenience of the extrusion technique for testing catalysts at simulated scale-up conditions.

关键词: MTO     SAPO-34     temperature     extrusion     coke     light alkanes    

Plasma-catalysis: Is it just a question of scale?

J. Christopher Whitehead

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 264-273 doi: 10.1007/s11705-019-1794-3

摘要: The issues of describing and understanding the changes in performance that result when a catalyst is placed into plasma are discussed. The different chemical and physical interactions that result and how their combination might produce beneficial results for the plasma-catalytic processing of different gas streams are outlined with particular emphasis being placed on the different range of spatial and temporal scales that must be considered both in experiment and modelling. The focus is on non-thermal plasma where the lack of thermal equilibrium creates a range of temperature scales that must be considered. This contributes in part to a wide range of inhomogeneity in different properties such as species concentrations and electric fields that must be determined experimentally by methods and be incorporated into modelling. It is concluded that plasma-catalysis is best regarded as conventional catalysis perturbed by the presence of a discharge, which modifies its operating conditions, properties and outcomes often in a very localised way. The sometimes used description “plasma-activated catalysis” is an apt one.

关键词: plasma catalysis     plasma-activated catalysis     non-thermal plasma     CO2 conversion    

Thermal decomposition of poly(ethylene terephthalate)/mesoporous molecular sieve composites

RUN Mingtao, ZHANG Dayu, WU Sizhu, WU Gang

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 50-54 doi: 10.1007/s11705-007-0010-z

摘要: The nonisothermal and isothermal degradation processes of poly (ethylene terephthalate)/mesoporous molecular sieve (PET/MMS) composites synthesized by in-situ polymerization were studied by using thermogravimetric analysis in nitrogen. The nonisothermal degradation of the composite is found to be the first-order reaction. An iso-conversional procedure developed by Ozawa is used to calculate the apparent activation energy (), which is an average value of about 260 kJ/mol with the weight conversion from 0% to 30%, and is higher than that of neat PET. Isothermal degradation results are confirmed with the nonisothermal process, in which PET/MMS showed higher thermal stability than neat PET. The polymer in mesoporous channels has more stability due to the protection of the inorganic pore-wall. These results indicate that mesoporous MMS in PET/MMS composites improve the stability of the polymer.

关键词: polymerization     isothermal degradation     conversion     nonisothermal degradation     activation    

Photocatalytic syngas synthesis from CO

Ling Tan, Kipkorir Peter, Jing Ren, Baoyang Du, Xiaojie Hao, Yufei Zhao, Yu-Fei Song

《化学科学与工程前沿(英文)》 2021年 第15卷 第1期   页码 99-108 doi: 10.1007/s11705-020-1947-4

摘要: The rational design of photocatalyst that can effectively reduce CO under visible light ( >400 nm), and simultaneously precise control of the products syngas (CO/H ) ratio is highly desirable for the Fischer-Tropsch reaction. In this work, we synthesized a series of CeO -decorated layered double hydroxides (LDHs, Ce- ) samples for photocatalytic CO reduction. It was found that the selectivity and productivity of CO and H from photoreduction of CO in conjunction with Ru-complex as photosensitizer performed an obvious “volcano-like” trend, with the highest point at Ce-0.15 and the CO/H ratio can be widely tunable from 1/7.7 to 1/1.3. Furthermore, compared with LDH, Ce-0.15 also drove photocatalytic CO to syngas under 600 nm irradiation. It implied that an optimum amount of CeO modifying LDH promoted the photoreduction of CO to syngas. This report gives the way to fully utilize the rare earth elements and provides a promising route to enhance the photo-response ability and charge injection efficiency of LDH-based photocatalysts in the synthesis of syngas with a tunable ratio under visible light irradiation.

关键词: visible light catalysis     CO2 conversion     layered double hydroxide     rare earth elements    

Hydrogel photocatalysts for efficient energy conversion and environmental treatment

《能源前沿(英文)》 2021年 第15卷 第3期   页码 577-595 doi: 10.1007/s11708-021-0756-x

摘要: Photocatalysts have attracted great research interest owing to their excellent properties and potential for simultaneously addressing challenges related to energy needs and environmental pollution. Photocatalytic particles need to be in contact with their respective media to exhibit efficient photocatalytic performances. However, it is difficult to separate nanometer-sized photocatalytic materials from reaction media later, which may lead to secondary pollution and a poor recycling performance. Hydrogel photocatalysts with a three-dimensional (3D) network structures are promising support materials for photocatalysts based on features such as high specific surface areas and adsorption capacities and good environmental compatibility. In this review, hydrogel photocatalysts are classified into two different categories depending on their elemental composition and recent progresses in the methods for preparing hydrogel photocatalysts are summarized. Moreover, current applications of hydrogel photocatalysts in energy conversion and environmental remediation are reviewed. Furthermore, a comprehensive outlook and highlight future challenges in the development of hydrogel photocatalysts are presented.

关键词: hydrogel     photocatalysts     energy conversion     environmental treatment    

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

Zhen Bi, Deqing Wanyan, Xiang Li, Yong Huang

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-019-1217-1

摘要: The SRAO phenomena tended to occur only under certain conditions. High amount of biomass and non-anaerobic condition is requirement for SRAO. Anammox bacteria cannot oxidize ammonium with sulfate as electron acceptor. AOB and AnAOB are mainly responsible for ammonium conversion. Heterotrophic sulfate reduction mainly contributed to sulfate conversion. For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. SRAO was considered an autotrophic process mediated by anammox bacteria, in which ammonium as electron donor was oxidized by the electron acceptor sulfate. This process had been attributed to observed transformations of nitrogenous and sulfurous compounds in natural environments. Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. Thus, the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible. In this study, continuous reactor experiments (with working volume of 3.8L) and batch tests were conducted under normal anaerobic (0.2≤DO<0.5 mg/L) / strict anaerobic (DO<0.2 mg/L) conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion. Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition, while absent under strict anaerobic conditions for same anammox consortia. Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed. Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could, in fact, be a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes.

关键词: Anammox bacteria     Autotrophic     Biological conversion     Sulfate reducing ammonium oxidation (SRAO)    

Photocatalysis: from solar light to hydrogen energy

《能源前沿(英文)》 2021年 第15卷 第3期   页码 565-567 doi: 10.1007/s11708-021-0784-6

Sustainable conversion regenerated cellulose into cellulose oleate by sonochemistry

《化学科学与工程前沿(英文)》 2023年 第17卷 第8期   页码 1096-1108 doi: 10.1007/s11705-023-2317-9

摘要: Derivatization has great potential for the high-value utilization of cellulose by enhancing its processability and functionality. However, due to the low reactivity of natural cellulose, it remains challenging to rapidly prepare cellulose derivatives with high degrees of substitution. The “cavitation effect” of ultrasound can reduce the particle size and crystalline index of cellulose, which provides a possible method for preparing cellulose derivatives. Herein, a feasible method was proposed for efficiently converting regenerated cellulose to cellulose oleate with the assistance of ultrasonic treatment. By adjusting the reaction conditions including ultrasonic intensity, feeding ratios of oleic acid, reaction time, and reaction solvent, a series of cellulose oleates with degrees of substitution ranging from 0.37 to 1.71 were synthesized. Additionally, the effects of different reaction conditions on the chemical structures, crystalline structures, and thermal behaviors were investigated thoroughly. Cellulose oleates with degrees of substitution exceeding 1.23 exhibited amorphous structures and thermoplasticity with glass transition temperatures at 159.8 to 172.6 °C. This study presented a sustainable and practicable method for effectively derivatizing cellulose.

关键词: regenerated cellulose     cellulose oleate     sonochemistry     degree of substitution     thermoplasticity    

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿(英文)》 2012年 第6卷 第2期   页码 184-192 doi: 10.1007/s11708-012-0185-y

摘要: Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.

关键词: doubly fed induction generator (DFIG)     load frequency control     inertial control     wind energy conversion system (WECS)    

标题 作者 时间 类型 操作

Encapsulation of polyethylene glycol in cellulose-based porous capsules for latent heat storage and light-to-thermalconversion

期刊论文

Effect of Fe content on FeMn catalysts for light alkenes synthesis

ZHOU Jun, CHU Wei, ZHANG Hui, XU Huiyuan, ZHANG Tao

期刊论文

Facile synthesis and enhanced visible-light photocatalytic activity of Ti

Xiaojie Zhang,Lei Wang,Shuqing Chen,Yi Huang,Zhuonan Song,Miao Yu

期刊论文

From plasma to plasmonics: toward sustainable and clean water production through membranes

期刊论文

Recent progress in MoS

Soheil RASHIDI, Akshay CARINGULA, Andy NGUYEN, Ijeoma OBI, Chioma OBI, Wei WEI

期刊论文

Benzene conversion by manganese dioxide assisted silent discharge plasma

LU Bin, JI Min, YU Xin, FENG Tao, YAO Shuiliang

期刊论文

Effect of temperature in the conversion of methanol to olefins (MTO) using an extruded SAPO-34 catalyst

Ignacio Jorge Castellanos-Beltran, Gnouyaro Palla Assima, Jean-Michel Lavoie

期刊论文

Plasma-catalysis: Is it just a question of scale?

J. Christopher Whitehead

期刊论文

Thermal decomposition of poly(ethylene terephthalate)/mesoporous molecular sieve composites

RUN Mingtao, ZHANG Dayu, WU Sizhu, WU Gang

期刊论文

Photocatalytic syngas synthesis from CO

Ling Tan, Kipkorir Peter, Jing Ren, Baoyang Du, Xiaojie Hao, Yufei Zhao, Yu-Fei Song

期刊论文

Hydrogel photocatalysts for efficient energy conversion and environmental treatment

期刊论文

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

Zhen Bi, Deqing Wanyan, Xiang Li, Yong Huang

期刊论文

Photocatalysis: from solar light to hydrogen energy

期刊论文

Sustainable conversion regenerated cellulose into cellulose oleate by sonochemistry

期刊论文

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文