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Effects of different sediment fractions on sorption of galaxolide

Lixia JIN, Mengchang HE, Jinghuan ZHANG

《环境科学与工程前沿(英文)》 2012年 第6卷 第1期   页码 59-65 doi: 10.1007/s11783-010-0259-1

摘要: Sorption isotherms of galaxolide (HHCB) of different fractions from two sediments with different mineral and organic carbon contents were determined to compare HHCB sorption behavior and contribution to the total sorption. The HHCB sorption isotherms that used the batch equilibration method were studied on different sediments of different fractions. The sorption isotherms of 600°C heating fractions were detailed using the linear model, while the other fractions were nonlinear and fitted well with the Freundlich model. The dissolved organic carbon (DOC) removed, NaOH extracted, and 375°C heating fractions showed more nonlinear sorption than the original sediments, which suggested more heterogeneous sorption sites in these fractions. Compared to the original sediments, the 375°C heating fractions had higher carbon-normalized distribution coefficient ( ) values, indicating a higher sorption affinity for HHCB. Among the different sediment fractions, the contribution of the 600°C heating fractions to the overall sorption were the lowest (<20%), while the 375°C heating fractions were the highest (up to 85%).

关键词: galaxolide (HHCB)     sorption     organic carbon     sediment     carbon-normalized distribution coefficient (Koc)    

Developing the QSPR model for predicting the storage lipid/water distribution coefficient of organic

Miao Li, Jian Li, Yuchen Lu, Cenyang Han, Xiaoxuan Wei, Guangcai Ma, Haiying Yu

《环境科学与工程前沿(英文)》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1316-z

摘要: Abstract • A predictive model for storage lipid/water distribution coefficient was developed. • The model yields outstanding fitting performance, robustness, and predictive ability. • Hydrophobic and electrostatic interactions and molecular size dominate log Klip/w. • The model can be used in a wide application domain to predict log Klip/w values. The distribution of organic compounds in stored lipids affects their migration, transformation, bioaccumulation, and toxicity in organisms. The storage lipid/water distribution coefficient (log Klip/w) of organic chemicals, which quantitatively determines such distribution, has become a key parameter to assist their ecological security and health risk. Due to the impossibility to measure Klip/w values for a huge amount of chemicals, it is necessary to develop predictive approaches. In this work, a quantitative structure-property relationship (QSPR) model for estimating log Klip/w values of small organic compounds was constructed based on 305 experimental log Klip/w values. Quantum chemical descriptors and n-octanol/water partitioning coefficient were employed to characterize the intermolecular interactions that dominate log Klip/w values. The hydrophobic and electrostatic interactions and molecular size have been found to play important roles in governing the distribution of chemicals between lipids and aqueous phases. The regression (R2 = 0.959) and validation (Q2 = 0.960) results indicate good fitting performance and robustness of the developed model. A comparison with the predictive performance of other commercial software further proves the higher accuracy and stronger predictive ability of the developed Klip/w predictive model. Thus, it can be used to predict the Klip/w values of cycloalkanes, long-chain alkanes, halides (with fluorine, chlorine, and bromine as substituents), esters (without phosphate groups), alcohols (without methoxy groups), and aromatic compounds.

关键词: Storage lipid/water distribution coefficient     log Klip/w     Organic compounds     QSPR     Quantum chemical descriptors    

Data-driven distribution network topology identification considering correlated generation power of distributed

《能源前沿(英文)》 2022年 第16卷 第1期   页码 121-129 doi: 10.1007/s11708-021-0780-x

摘要: This paper proposes a data-driven topology identification method for distribution systems with distributed energy resources (DERs). First, a neural network is trained to depict the relationship between nodal power injections and voltage magnitude measurements, and then it is used to generate synthetic measurements under independent nodal power injections, thus eliminating the influence of correlated nodal power injections on topology identification. Second, a maximal information coefficient-based maximum spanning tree algorithm is developed to obtain the network topology by evaluating the dependence among the synthetic measurements. The proposed method is tested on different distribution networks and the simulation results are compared with those of other methods to validate the effectiveness of the proposed method.

关键词: power distribution network     data-driven     topology identification     distributed energy resource     maximal information coefficient    

A model of

Jingyu WANG,Hongwei FANG,Guojian HE,Lei HUANG

《环境科学与工程前沿(英文)》 2014年 第8卷 第6期   页码 845-853 doi: 10.1007/s11783-014-0708-3

摘要: The impact on the environment of radionuclide release from nuclear power plants has attracted increased attention, especially after the accident at Fukushima Daiichi Nuclear Power Plant in Japan. Based on the mechanisms of adsorption/desorption at solid/liquid interfaces and a surface micromorphology model of sediments, a theoretical expression of the distribution coefficient is derived. This coefficient has significant effects on the distribution of radionuclide in seawater, suspended sediment and seabed sediment. is then used to simulate Sr transport in the sea near the Daya Bay Nuclear Power Plant. The simulation results are compared with field measurements of tidal level, current velocity, suspended sediment concentration and Sr concentrations in the same period. Overall, the simulated results agree well with the field measured data. Thus, the derived expression for is capable of interpreting realistic adsorption/desorption processes. What’s more, conclusion is drawn that about 40% Sr released by Daya Bay Nuclear Power Plant will be adsorbed by suspended sediment and 20% by seabed sediment, only about 40% Sr will remain in the sea near Daya Bay Nuclear Power Plant in South China Sea.

关键词: distribution coefficient     Daya Bay     hydrodynamic     sediment transport     radionuclide transport    

Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulse

Bin Xu, Toshiro Kaneko, Toshiaki Kato

《化学科学与工程前沿(英文)》 2019年 第13卷 第3期   页码 485-492 doi: 10.1007/s11705-019-1831-2

摘要: A pulse plasma chemical vapor deposition (CVD) technique was developed for improving the growth yield of single-walled carbon nanotubes (SWNTs) with a narrow chirality distribution. The growth yield of the SWNTs could be improved by repetitive short duration pulse plasma CVD, while maintaining the initial narrow chirality distribution. Detailed growth dynamics is discussed based on a systematic investigation by changing the pulse parameters. The growth of SWNTs with a narrow chirality distribution could be controlled by the difference in the nucleation time required using catalysts comprising relatively small or large particles as the key factor. The nucleation can be controlled by adjusting the pulse on/off time ratio and the total processing time.

关键词: single-walled carbon nanotubes     chirality-controlled synthesis     pulse plasma chemical vapor deposition    

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinkingwater distribution system

Yongji ZHANG, Lingling ZHOU, Guo ZENG, Huiping DENG, Guibai LI

《环境科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 430-437 doi: 10.1007/s11783-010-0247-5

摘要: Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters. The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination. The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors (RAB) with different chlorine to ammonia ratios and total organic carbon (TOC) levels. The results indicated that nitrification occurred despite at a low influent concentration of ammonia, and a high concentration of nitrite nitrogen was detected in the effluent. The study illustrated that reactors 1(R1) and 3 (R3), with higher TOC levels, produced more nitrite nitrogen, which was consistent with the ammonia-oxidizing bacteria (AOB) counts, and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts (R2 and R4). The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification. Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors. The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification. Bulk water with a high TOC level supported the occurrence of nitrification, and AOB development occurred at all examined chlorine to ammonia dose ratios (3∶1 or 5∶1).

关键词: nitrification     drinking water     ammonia- oxidizing bacteria (AOB)     chloramines     organic carbon     heterotrophic bacteria    

Distribution and temporal variability of the solar resource at a site in south-east Norway

Muyiwa S. ADARAMOLA

《能源前沿(英文)》 2016年 第10卷 第4期   页码 375-381 doi: 10.1007/s11708-016-0426-6

摘要: Globally, solar energy is expected to play a significant role in the changing face of energy economies in the near future. However, the variability of this resource has been the main barrier for solar energy development in most locations around the world. This paper investigated the distribution and variability of solar radiation using the a 10-year (2006 to 2015) data collected at Sørås meteorological station located at latitude 59° 39′ N and longitude 10° 47′E, about 93.3 m above sea level (about 30 km from Oslo), in south-eastern part of Norway. It is found that on annual basis, the total number of days with a global solar radiation of less than 1 kWh/(m ·d) is 120 days while the total number of days with an expected global solar radiation greater than 3 kWh/(m ·d) is 156 days (42.74%) per year. The potential energy output from a horizontally placed solar collector in these 156 days is approximately 75% of the estimated annual energy output. In addition, it is found that the inter-annual coefficient of variation of the global solar radiation is 4.28%, while that of diffuse radiation is 4.96%.

关键词: coefficient of variation     global solar radiation     diffuse ratio     albedo     PV energy systems    

Unnormalized and normalized forms of gefura measures in directed and undirected networks

Raf GUNS,Ronald ROUSSEAU

《信息与电子工程前沿(英文)》 2015年 第16卷 第4期   页码 311-320 doi: 10.1631/FITEE.1400425

摘要: In some networks nodes belong to predefined groups (e.g., authors belong to institutions). Common network centrality measures do not take this structure into account. Gefura measures are designed as indicators of a node’s brokerage role between such groups. They are defined as variants of betweenness centrality and consider to what extent a node belongs to shortest paths between nodes from different groups. In this article we make the following new contributions to their study: (1) We systematically study unnormalized gefura measures and show that, next to the ‘structural’ normalization that has hitherto been applied, a ‘basic’ normalization procedure is possible. While the former normalizes at the level of groups, the latter normalizes at the level of nodes. (2) Treating undirected networks as equivalent to symmetric directed networks, we expand the definition of gefura measures to the directed case. (3) It is shown how Brandes’ algorithm for betweenness centrality can be adjusted to cover these cases.

关键词: Networks subdivided in groups     Partitions     Gefura measures     Q-measures     Brokerage role     Directed and undirected networks     Brandes’     algorithm    

Efficient CO

Yanxia Wang, Xiude Hu, Tuo Guo, Jian Hao, Chongdian Si, Qingjie Guo

《化学科学与工程前沿(英文)》 2021年 第15卷 第3期   页码 493-504 doi: 10.1007/s11705-020-1967-0

摘要: In this work, nitrogen-doped porous carbons (NACs) were fabricated as an adsorbent by urea modification and KOH activation. The CO adsorption mechanism for the NACs was then explored. The NACs are found to present a large specific surface area (1920.72–3078.99 m ·g ) and high micropore percentage (61.60%–76.23%). Under a pressure of 1 bar, sample NAC-650-650 shows the highest CO adsorption capacity up to 5.96 and 3.92 mmol·g at 0 and 25 °C, respectively. In addition, the CO /N selectivity of NAC-650-650 is 79.93, much higher than the value of 49.77 obtained for the nonnitrogen-doped carbon AC-650-650. The CO adsorption capacity of the NAC-650-650 sample maintains over 97% after ten cycles. Analysis of the results show that the CO capacity of the NACs has a linear correlation ( = 0.9633) with the cumulative pore volume for a pore size less than 1.02 nm. The presence of nitrogen and oxygen enhances the CO /N selectivity, and pyrrole-N and hydroxy groups contribute more to the CO adsorption. Fourier transform infrared spectra analysis indicates that CO is adsorbed onto the NACs as a gas. Furthermore, the physical adsorption mechanism is confirmed by adsorption kinetic models and the isosteric heat, and it is found to be controlled by CO diffusion. The CO adsorption kinetics for NACs at room temperature and in pure CO is in accordance with the pseudo-first-order model and Avramís fractional-order kinetic model.

关键词: porous carbon     CO2 adsorption     nitrogen-doped     adsorption mechanism     kinetics    

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2161-2161 doi: 10.1007/s11705-009-0143-3

摘要: RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

关键词: tee junction     Momentum exchange coefficient     RETRACTED    

Simulation on thermodynamic state of ammonia carbonation at low temperature and low pressure

Jingcai ZHAO, Xingfu SONG, Ze SUN, Jianguo YU

《化学科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 447-455 doi: 10.1007/s11705-013-1370-1

摘要: This study on thermodynamic property of NH -CO -H O system provided the basic data for ammonia carbonation. Simulations on vapor-liquid equilibrium (VLE) of ammonia carbonation with different physical properties were discussed in NH -H O and NH -CO -H O systems, respectively. The results indicated that at low temperature (303.15 K–363.15 K) and pressure (0.1–0.4 MPa), the PR (Peng-Robinson) equation was suitable for the description of the thermodynamic state in NH -H O system. NRTL (Non-Random-Two-Liquid) series models were selected for NH -CO -H O mixed electrolyte solution system. VLE data regression results showed that NRTL series models were suitable for describing thermodynamic properties of NH -CO -H O system, because average relative error fitting with each model was about 1%. As an asymmetric electrolytes model in NRTL model, E–NRTLRK (Electrolyte NRTL Redlich Kwong) could most accurately fit VLE data of NH -CO -H O system, with fitting error less than 1%. In the extent temperature range of 273.15 K–363.15 K, the prediction of product component using E-NRTLRK model for ammonia carbonation agreed well with the data reported in literature.

关键词: vapor-liquid equilibrium     activity coefficient     carbon dioxide     ammonia     NRTL    

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

《能源前沿(英文)》 2014年 第8卷 第2期   页码 160-172 doi: 10.1007/s11708-014-0321-y

摘要: This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions.

关键词: Nusselt number     flow rate     heat transfer     heat transfer coefficient     thermal efficiency     forced convection    

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 428-437 doi: 10.1007/s11783-015-0780-3

摘要: UV photolysis and UV based advanced oxidation processes (AOPs) are gaining more and more attention for drinking water treatment. Quantum yield ( ) and molar absorption coefficient ( ) are the two critical parameters measuring the effectiveness of photolysis of a compound. The product of the two was proposed as a fundamental measure of a constituent’s amenability to transformation by photolysis. It was shown that this product, named the photolysis coefficient, , can be determined using standard bench tests and captures the properties that govern a constituent’s transformation when exposed to light. The development showed the photolysis coefficient to be equally useful for microbiological, inorganic and organic constituents. Values of calculated by the authors based on quantum yield and molar absorption coefficient data from the literature were summarized. Photolysis coefficients among microorganisms ranged from 8500 to more than 600000 and are far higher than for inorganic and organic compounds, which varied over a range of approximately 10 to 1000 and are much less sensitive to UV photolysis than the microorganisms.

关键词: UV photolysis     disinfection     advanced oxidation     N-nitrosodimethylamine     quantum yield     absorption coefficient    

Characterization of the dissolved organic matter in sewage effluent of sequence batch reactor: the impact of carbon

Jin GUO, Feng SHENG, Jianhua GUO, Xiong YANG, Mintao MA, Yongzhen PENG

《环境科学与工程前沿(英文)》 2012年 第6卷 第2期   页码 280-287 doi: 10.1007/s11783-011-0336-0

摘要: Dissolved organic matter (DOM) transformation in sequence batch reactor (SBR) fed with carbon sources of different biodegradability was investigated. During the biologic degradation process, the low molecular weight (MW) fraction (<1 kDa) gradually decreased, while the refractory compounds with higher aromaticity were aggregated. Size exclusion chromatography (SEC) and fluorescence of excitation emission matrices (EEM) demonstrated that more biopolymers (polysaccharides or proteins) and humic-like substances were presented in the extracellular polymeric substance (EPS) extracted from the SBR fed with sodium acetate or glucose, while the EPS from SBR fed with slowly biodegradable dissolved organic carbon (DOC) substrate-starch had relatively less biopolymers. Comparing the EfOM in sewage effluent of three SBRs, the effluent from SBR fed with starch is more aromatic. Organic carbon with MW>1 kDa as well as the hydrophobic fraction in DOM gradually increased with the carbon sources changing from sodium acetate to glucose and starch. The DOC fractionation and the EEM all demonstrated that EfOM from the effluent of the SBR fed with starch contained more fulvic acid-like substances comparing with the SBR fed with sodium acetate and glucose.

关键词: effluent organic matter (EfOM)     extracellular polymeric substance (EPS)     molecular weight distribution (MWD)     hydrophobic     hydrophilic     excitation emission matrices (EEM)    

Effect of heat transfer coefficient of steam turbine rotor on thermal stress field under off-design condition

Jie GUO,Danmei XIE,Hengliang ZHANG,Wei JIANG,Yan ZHOU

《能源前沿(英文)》 2016年 第10卷 第1期   页码 57-64 doi: 10.1007/s11708-015-0385-3

摘要: The precise calculation of temperature and thermal stress field of steam turbine rotor under off-design conditions is of paramount significance for safe and economic operation, in which an accurate calculation of heat transfer (HT) coefficient plays a decisive role. HT coefficient changes dramatically along with working conditions. First, a finite element analysis of rotor model, applied with ordinary rotor materials, has been conducted to investigate the temperature and thermal stress difference along with the change of HT coefficient from 20 W/(m ·°C) to 20000 W/(m ·°C). Next, the differentiation between existing empirical formulas has been analyzed from the aspect of physical significance of non-dimension parameters. Finally, a verifying case of the cold startup of a 1000MW unit has been proceeded. The result shows that the accuracy of coefficient calculation when steam parameters are low has a greater influence on that of rotor temperature and thermal stress, which means a precise empirical HT coefficient formula, like the Sarkar formula is strongly recommended. When steam parameters are high and HT coefficient is larger than 10 W/(m ·°C), there will be barely any influence on the calculation of thermal stress. This research plays a constructive role in the calculation and analysis of thermal stress.

关键词: steam turbine     rotor     thermal stress     heat transfer coefficient     empirical formula    

标题 作者 时间 类型 操作

Effects of different sediment fractions on sorption of galaxolide

Lixia JIN, Mengchang HE, Jinghuan ZHANG

期刊论文

Developing the QSPR model for predicting the storage lipid/water distribution coefficient of organic

Miao Li, Jian Li, Yuchen Lu, Cenyang Han, Xiaoxuan Wei, Guangcai Ma, Haiying Yu

期刊论文

Data-driven distribution network topology identification considering correlated generation power of distributed

期刊论文

A model of

Jingyu WANG,Hongwei FANG,Guojian HE,Lei HUANG

期刊论文

Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulse

Bin Xu, Toshiro Kaneko, Toshiaki Kato

期刊论文

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinkingwater distribution system

Yongji ZHANG, Lingling ZHOU, Guo ZENG, Huiping DENG, Guibai LI

期刊论文

Distribution and temporal variability of the solar resource at a site in south-east Norway

Muyiwa S. ADARAMOLA

期刊论文

Unnormalized and normalized forms of gefura measures in directed and undirected networks

Raf GUNS,Ronald ROUSSEAU

期刊论文

Efficient CO

Yanxia Wang, Xiude Hu, Tuo Guo, Jian Hao, Chongdian Si, Qingjie Guo

期刊论文

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

期刊论文

Simulation on thermodynamic state of ammonia carbonation at low temperature and low pressure

Jingcai ZHAO, Xingfu SONG, Ze SUN, Jianguo YU

期刊论文

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

Foued CHABANE,Nesrine HATRAF,Noureddine MOUMMI

期刊论文

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

期刊论文

Characterization of the dissolved organic matter in sewage effluent of sequence batch reactor: the impact of carbon

Jin GUO, Feng SHENG, Jianhua GUO, Xiong YANG, Mintao MA, Yongzhen PENG

期刊论文

Effect of heat transfer coefficient of steam turbine rotor on thermal stress field under off-design condition

Jie GUO,Danmei XIE,Hengliang ZHANG,Wei JIANG,Yan ZHOU

期刊论文