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期刊论文 1352

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Relationships of nitrous oxide fluxes with water quality parameters in free water surface constructed

Juan WU, Jian ZHANG, Wenlin JIA, Huijun XIE, Bo ZHANG

《环境科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 241-247 doi: 10.1007/s11783-009-0023-6

摘要: The effects of chemical oxygen demand (COD) concentration in the influent on nitrous oxide (N O) emissions, together with the relationships between N O and water quality parameters in free water surface constructed wetlands, were investigated with laboratory-scale systems. N O emission and purification performance of wastewater were very strongly dependent on COD concentration in the influent, and the total N O emission in the system with middle COD influent concentration was the least. The relationships between N O and the chemical and physical water quality variables were studied by using principal component scores in multiple linear regression analysis to predict N O flux. The multiple linear regression model against principal components indicated that different water parameters affected N O flux with different COD concentrations in the influent, but nitrate nitrogen affected N O flux in all systems.

关键词: free water surface constructed wetland     nitrous oxide emission     water quality parameter     principal component analysis     multiple linear regression    

Environmental dispersivity in free-water-surface-effect dominated wetland: multi-scale analysis

Zi WU, Zhi LI, Li ZENG, Ling SHAO, Hansong TANG, Qing YANG, Guoqian CHEN

《环境科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 597-603 doi: 10.1007/s11783-011-0311-9

摘要: Distinct from the case with width-dominated shallow wetland flows, the longitudinal evolution of contaminant concentration in the most-typical pattern of wetland as dominated by free-water-surface-effect is characterized by a multi-scale analysis in the present study. An environmental dispersion model for the evolution of the mean concentration is deduced as an extension of Taylor's classical formulation by Mei’s multi-scale analysis. Corresponding environmental dispersivity is found identical to that determined by the method of concentration moments.

关键词: free-surface wetland     environmental dispersion     multi-scale analysis    

Formation of free-charging industry alliance for new energy vehicles

Zhengdong YANG, Feng JIN, Shiyu DU, Jingwen LI

《工程管理前沿(英文)》 2018年 第5卷 第2期   页码 268-275 doi: 10.15302/J-FEM-2018058

摘要: At present, the further development of new energy vehicles industry is hindered by limited consumer’s participation or capital investment. Therefore, a new multilateral model of cross-industry alliance needs to arise. The advanced charging technology of Internet-distributed mobile energy can link up with many market participants closely and form an effective and multilateral win-win cross-industry alliance. This new industry alliance can realize unexpected multiple goals, for example, (1) consumers who have purchased new energy vehicles can avail free charging; (2) potential vehicle buyers can be encouraged to use new energy vehicles; (3) the new energy vehicle manufacturers can expand their production scale; (4) the new energy vehicles sellers (4S shop) can expand their sales volume; (5) large shopping malls can attain more income; (6) financial institutions can absorb more deposits; (7) governments can further promote low-carbon traffic. This article analyzes the cross-industry alliance and its forming mechanism.

关键词: industry alliance     mobile energy     new energy vehicles     free charging     low carbon    

Closed surface modeling with helical line measurement data

LI Ruqiong, LI Guangbu, WANG Yuhan

《机械工程前沿(英文)》 2007年 第2卷 第1期   页码 72-76 doi: 10.1007/s11465-007-0012-z

摘要: Models for surface modeling of free-form surface and massive data points are becoming an important feature in commercial computer aided design/computer-aided manufacturing software. However, there are many problems to be solved in this area, especially for closed free-form surface modeling. This article presents an effective method for cloud data closed surface modeling from asynchronous profile modeling measurement. It includes three steps: first, the cloud data are preprocessed for smoothing; second, a helical line is segmented to form triangle meshes; and third, Bezier surface patches are created over a triangle mesh and trimmed to shape on an entire surface. In the end, an illustrative example of shoe last surface modeling is given to show the availability of this method.

关键词: free-form surface     helical     triangle     design/computer-aided manufacturing     effective    

Dynamic analysis of free-surface thin film flows driven by gravity over undulated substrate

Zhaomiao LIU, Xin LIU, Guobin WANG, Hong LIAO,

《机械工程前沿(英文)》 2010年 第5卷 第2期   页码 219-225 doi: 10.1007/s11465-010-0010-4

摘要: This paper studies thin film flows with free surfaces driven by gravity through two types of undulated planes: periodically sinusoidal plane and triangle. The substrate plane is fixed and inclined to a certain angle and the flow with a free surface. Through finite element method (FEM), commenced from Navier-Stokes equations and continuity equation, the exact numerical results of free-surface film flows are obtained through discretization solution to finite equations in flowing areas. Based on the numerical calculations, the streamlines and wall shearing stress during the flowing process are visualized via post-proceeding, and the streamlines separation, the onset and evolution of vortex near the substrate boundary during the flow are also analyzed. The influences from the waviness of the substrate planes profile, height of the triangle plane, and change of the film height on film flow dynamics properties are shown.

关键词: waviness     triangle height     film thickness     streamlines separation     vortex    

The energy-free purification of trace thallium(I)-contaminated potable water using a high-selective filter

《化学科学与工程前沿(英文)》 doi: 10.1007/s11705-023-2379-8

摘要: Thallium is a highly toxic metal, and trace amount of thallium(I) (Tl+) in potable water could cause a severe water crisis, which arouses the exploitation of highly-effective technology for purification of Tl+ contaminated water. This report proposes the multi-layered Prussian blue (PB)-decorated composite membranes (PBx@PDA/PEI-FP) based on the aminated filter papers for Tl+ uptake. Extensively characterization by Fourier transform infrared spectrometer-attenuated total reflectance, scanning electron microscope, thermogravimetric analysis, X-ray photoelectron spectroscopy and X-ray diffraction were performed to confirm the in situ growth of cubic PB crystals on filter paper membrane surfaces via the aminated layers, and the successful fabrication of multi-layered PB overcoats via the increasing of aminated layers. The effect of PB layers on Tl+ removal by PBx@PDA/PEI-FP from simulated drinking water was evaluated as well as the influence of different experimental conditions. A trade-off between PB decoration layer number and PB distribution sizes is existed in Tl+ uptake by PBx@PDA/PEI-FP. The double-layered PB2@PDA/PEI-FP membrane showed the maximum sorption capacity, but its Tl+ uptake performance was weakened by the acid, coexisting ions (K+ and Na+) and powerful operation pressure, during filtrating a large volume of low-concentrated Tl+-containing water. However, the negative effect of coexisting ions on the Tl+ uptake could be effectively eliminated in weak alkaline water, and the Tl+ removal was increased up to 100% without any pressure driving for PB2@PDA/PEI-FP membrane. Most importantly, PB2@PDA/PEI-FP displayed the high-efficiency and high-selectivity in purifying the Tl+-spiked Pearl River water, in which the residual Tl+ in filtrate was less than 2 μg·L–1 to meet the drinking water standard of United States Environmental Protection Agency. This work provides a feasible avenue to safeguard the drinking water in remote and underdeveloped area via the energy-free operation.

关键词: membrane adsorption     Prussian blue     energy-free filtration     potable water     trace thallium(I)    

Solvent-free mechanochemical mild oxidation method to enhance adsorption properties of chitosan

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1416-4

摘要:

• Solvent-free chitosan oxidation is obtained by rapid mechanochemical reaction.

关键词: Chitosan     High energy ball milling     Mechanochemistry     Oxidation    

Lamellar thickness transition of melt-crystallized polybuten-1 tetragonal phase: configurational change in chain folding directions

Motoi YAMASHITA

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 26-32 doi: 10.1007/s11705-009-0002-2

摘要: Lamellar crystal thickness of isotactic polybutene-1 ( -PB1) have been investigated for crystallization in the melt over a wide range of crystallization temperature from 40°C to 90°C by small angle X-ray scattering experiments and density measurements. The crystal thickness demonstrates two linear dependences on inverse supercooling and a transition from one dependence to the other has been observed around = 65°C. Each of the two dependences obeys the nucleation theory in the high and low supercooling ranges, respectively. Chain folding free energy determined from the low supercooling range is larger than that determined from the high supercooling range. Possible mechanisms for the transition are discussed taking account of entropy of chain folding directions.

关键词: isotactic polybutene-1     tetragonal phase     crystal thickness     melt growth     chain folding     small angle X-ray scattering     nucleation theory     end surface free energy    

Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

《能源前沿(英文)》 2011年 第5卷 第1期   页码 69-74 doi: 10.1007/s11708-010-0117-7

摘要: A coal-fired power unit frequently operates under unsteady conditions; thus, in order to acquire scientific energy analysis of the unit, thermodynamic analysis of a single-phase heated surface in a boiler under such conditions requires investigation. Processes are analyzed, and distributions of energy and exergy are qualitatively revealed. Models for energy analysis, entropy analysis, and exergy analysis of control volumes and irreversible heat transfer processes are established. Taking the low-temperature superheater of a 610 t/h-boiler as an example, the distribution of energy, entropy production, and exergy is depicted quantitatively, and the results are analyzed.

关键词: thermodynamic model     energy distribution     boiler     unsteady conditions    

Towards Cr(VI)-free anodization of aluminum alloys for aerospace adhesive bonding applications: A review

Shoshan T. Abrahami, John M. M. de Kok, Herman Terryn, Johannes M. C. Mol

《化学科学与工程前沿(英文)》 2017年 第11卷 第3期   页码 465-482 doi: 10.1007/s11705-017-1641-3

摘要: For more than six decades, chromic acid anodizing (CAA) has been the central process in the surface pre-treatment of aluminum for adhesively bonded aircraft structures. Unfortunately, this electrolyte contains hexavalent chromium (Cr(VI)), a compound known for its toxicity and carcinogenic properties. To comply with the new strict international regulations, the Cr(VI)-era will soon have to come to an end. Anodizing aluminum in acid electrolytes produces a self-ordered porous oxide layer. Although different acids can be used to create this type of structure, the excellent adhesion and corrosion resistance that is currently achieved by the complete Cr(VI)-based process is not easily matched. This paper provides a critical overview and appraisal of proposed alternatives to CAA, including combinations of multiple anodizing steps, pre- and post anodizing treatments. The work is presented in terms of the modifications to the oxide properties, such as morphological features (e.g., pore size, barrier layer thickness) and surface chemistry, in order to evaluate the link between fundamental principles of adhesion and bond performance.

关键词: aluminum     Cr(VI)-free     surface pre-treatments     anodizing     adhesive bonding    

Using thermodynamic parameters to study self-healing and interface properties of crumb rubber modified asphalt based on molecular dynamics simulation

Dongliang HU, Jianzhong PEI, Rui LI, Jiupeng ZHANG, Yanshun JIA, Zepeng FAN

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 109-122 doi: 10.1007/s11709-019-0579-6

摘要: The thermodynamic property of asphalt binder is changed by the addition of crumb rubber, which in turn influences the self-healing property as well as the cohesion and adhesion within the asphalt-aggregate system. This study investigated the self-healing and interface properties of crumb rubber modified asphalt (CRMA) using thermodynamic parameters based on the molecular simulation approach. The molecular models of CRMA were built with representative structures of the virgin asphalt and the crumb rubber. The aggregate was represented by SiO and Al O crystals. The self-healing capability was evaluated with the thermodynamic parameter wetting time, work of cohesion and diffusivity. The interface properties were evaluated by characterizing the adhesion capability, the debonding potential and the moisture susceptibility of the asphalt-aggregate interface. The self-healing capability of CRMA is found to decrease as the rubber content increases. The asphalt-Al O interface with higher rubber content has stronger adhesion and moisture stability. But the influence of crumb rubber on the interfacial properties of asphalt-SiO interface has no statistical significance. Comparing with the interfacial properties of the asphalt-SiO interface, the asphalt-Al O interface is found to have a stronger adhesion but a worse moisture susceptibility for its enormous thermodynamic potential for water to displace the asphalt binder.

关键词: crumb rubber modified asphalt     surface free energy     self-healing     interface properties     molecular dynamics simulation    

Full-band error control and crack-free surface fabrication techniques for ultra-precision fly cutting

F. H. ZHANG, S. F. WANG, C. H. AN, J. WANG, Q. XU

《机械工程前沿(英文)》 2017年 第12卷 第2期   页码 193-202 doi: 10.1007/s11465-017-0448-8

摘要:

Large-aperture potassium dihydrogen phosphate (KDP) crystals are widely used in the laser path of inertial confinement fusion (ICF) systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machining errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.

关键词: ultra-precision fly cutting     large-aperture KDP crystals     spatial frequency     processing error    

A space power system of free piston Stirling generator based on potassium heat pipe

Mingqiang LIN, Jian MOU, Chunyun CHI, Guotong HONG, Panhe GE, Gu HU

《能源前沿(英文)》 2020年 第14卷 第1期   页码 1-10 doi: 10.1007/s11708-019-0655-6

摘要: The power system of a free piston Stirling generator (FPSG) based on potassium heat pipes has been developed in this paper. Thanks to the advantages of long life, high reliability, and high overall thermal efficiency, the FPSG is a promising candidate for nuclear energy, especially in space exploration. In this paper, the recent progress of FPSG based on nuclear reactor for space use was briefly reviewed. A novel FPSG weighted only 4.2 kg was designed, and one dimensional thermodynamic modeling of the FPSG using Sage software was performed to estimate its performance. The experiment results indicated that this FPSG could provide 142.4 W at a thermal-to-electric efficiency of nearly 17.4%. Besides, the power system integrated with four FPSGs and potassium heat pipes was performed and the single machine failure test was conducted. The results show that this system could provide an electrical power of 300 W at an overall thermal efficiency of 7.3%. Thus, it is concluded that this power system is feasible and will have a great prospect for future applications.

关键词: free piston Stirling generator (FPSG)     potassium heat pipe     power system     energy conversion    

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 606-624 doi: 10.1007/s11709-023-0925-6

摘要: A novel cambered surface steel tube damper (CSTD) with a cambered surface steel tube and two concave connecting plates is proposed herein. The steel tube is the main energy dissipation component and comprises a weakened segment in the middle, a transition segment, and an embedded segment. It is believed that during an earthquake, the middle weakened segment of the CSTD will be damaged, whereas the reliability of the end connection is ensured. Theoretical and experimental studies are conducted to verify the effectiveness of the proposed CSTD. Formulas for the initial stiffness and yield force of the CSTD are proposed. Subsequently, two CSTD specimens with different steel tube thicknesses are fabricated and tested under cyclic quasi-static loads. The result shows that the CSTD yields a stable hysteretic response and affords excellent energy dissipation. A parametric study is conducted to investigate the effects of the steel tube height, diameter, and thickness on the seismic performance of the CSTD. Compared with equal-stiffness design steel tube dampers, the CSTD exhibits better energy dissipation performance, more stable hysteretic response, and better uniformity in plastic deformation distributions.

关键词: cambered surface steel tube damper     energy dissipation capacity     finite element model     hysteretic performance     parametric study    

Characteristics and application of road absorbing solar energy

Zhihua ZHOU, Shan HU, Xiaoyan ZHANG, Jian ZUO

《能源前沿(英文)》 2013年 第7卷 第4期   页码 525-534 doi: 10.1007/s11708-013-0278-2

摘要: If the heat of road surface can be stored in summer, the road surface temperature will be decreased to prevent permanent deformation of pavement. Besides, if the heat stored is released, it can supply heat for buildings or raise the road surface temperature for snow melting in winter. A road-solar energy system was built in this study, and the heat transfer mechanism and effect of the system were analyzed according to the monitored solar radiant heat, the solar energy absorbed by road and the heat stored by soil. The results showed that the road surface temperature was mainly affected by solar radiation, but the effect is hysteretic in nature. The temperature of the solar road surface was 3°C–6°C lower than that of the ordinary road surface. The temperature of the solar road along the vertical direction was 2°C–5°C lower than that of the ordinary road. The temperature difference increased as the distance to the heat transfer tubes decreased. The average solar collector efficiency of the system was 14.4%, and the average solar absorptivity of road surface was 36%.

关键词: solar energy     road-solar energy system     road surface temperature     solar absorptivity of road surface     solar collector efficiency of system    

标题 作者 时间 类型 操作

Relationships of nitrous oxide fluxes with water quality parameters in free water surface constructed

Juan WU, Jian ZHANG, Wenlin JIA, Huijun XIE, Bo ZHANG

期刊论文

Environmental dispersivity in free-water-surface-effect dominated wetland: multi-scale analysis

Zi WU, Zhi LI, Li ZENG, Ling SHAO, Hansong TANG, Qing YANG, Guoqian CHEN

期刊论文

Formation of free-charging industry alliance for new energy vehicles

Zhengdong YANG, Feng JIN, Shiyu DU, Jingwen LI

期刊论文

Closed surface modeling with helical line measurement data

LI Ruqiong, LI Guangbu, WANG Yuhan

期刊论文

Dynamic analysis of free-surface thin film flows driven by gravity over undulated substrate

Zhaomiao LIU, Xin LIU, Guobin WANG, Hong LIAO,

期刊论文

The energy-free purification of trace thallium(I)-contaminated potable water using a high-selective filter

期刊论文

Solvent-free mechanochemical mild oxidation method to enhance adsorption properties of chitosan

期刊论文

Lamellar thickness transition of melt-crystallized polybuten-1 tetragonal phase: configurational change in chain folding directions

Motoi YAMASHITA

期刊论文

Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

期刊论文

Towards Cr(VI)-free anodization of aluminum alloys for aerospace adhesive bonding applications: A review

Shoshan T. Abrahami, John M. M. de Kok, Herman Terryn, Johannes M. C. Mol

期刊论文

Using thermodynamic parameters to study self-healing and interface properties of crumb rubber modified asphalt based on molecular dynamics simulation

Dongliang HU, Jianzhong PEI, Rui LI, Jiupeng ZHANG, Yanshun JIA, Zepeng FAN

期刊论文

Full-band error control and crack-free surface fabrication techniques for ultra-precision fly cutting

F. H. ZHANG, S. F. WANG, C. H. AN, J. WANG, Q. XU

期刊论文

A space power system of free piston Stirling generator based on potassium heat pipe

Mingqiang LIN, Jian MOU, Chunyun CHI, Guotong HONG, Panhe GE, Gu HU

期刊论文

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

期刊论文

Characteristics and application of road absorbing solar energy

Zhihua ZHOU, Shan HU, Xiaoyan ZHANG, Jian ZUO

期刊论文