资源类型

期刊论文 124

会议视频 3

年份

2023 6

2022 10

2021 9

2020 6

2019 9

2018 4

2017 7

2016 13

2015 10

2014 13

2013 7

2012 3

2011 2

2010 2

2009 3

2008 6

2007 5

2005 2

2004 1

2003 1

展开 ︾

关键词

2021全球十大工程成就 2

10kV高压电力电缆 1

ANSYS二次开发 1

CMAQ模型 1

Cuk矩阵变换器 1

DNA组装 1

Grade 91钢 1

KD技术标准 1

KD挑战性问题 1

KD核心问题 1

KD猜想 1

LM331型电压-频率转换器 1

PM2.5 1

Visual Basic 6.0 1

WANO化学性能指标 1

qPCR 1

万维网 1

中压变频 1

串并联谐振变换器;全桥;半桥;变频;移相;宽范围输入电压 1

展开 ︾

检索范围:

排序: 展示方式:

Solid-state transformer-based new traction drive system and control

Jianghua FENG, Jing SHANG, Zhixue ZHANG, Huadong LIU, Zihao HUANG

《机械工程前沿(英文)》 2018年 第13卷 第3期   页码 411-426 doi: 10.1007/s11465-018-0467-0

摘要:

A new type of traction drive system consisting of solid-state traction transformer (SSTT), inverter unit, auxiliary inverter, traction motor and other key components is built in order to suit the demand of developing the next-generation electric traction system which will be efficient and lightweight, with high power density. For the purpose of reducing system volume and weight and improving efficiency and grid-side power quality, an efficient SSTT optimized topology combining high-voltage cascaded rectifiers with high-power high-frequency LLC resonant converter is proposed. On this basis, an integrated control strategy built upon synchronous rotating reference frame is presented to achieve unified control over fundamental active, reactive and harmonic components. The carrier-interleaving phase shift modulation strategy is proposed to improve the harmonic performance of cascaded rectifiers. In view of the secondary pulsating existing in a single-phase system, the mathematical model of secondary power transfer is built, and the mechanism of pulsating voltage resulting in beat frequency of LLC resonant converter is revealed, so as to design optimum matching of system parameters. Simulation and experimental results have verified that the traction system and control scheme mentioned in this paper are reasonable and superior and that they meet the future application requirements for rail transit.

关键词: solid-state traction transformer     high-voltage cascaded rectifier     LLC resonant converter     synchronous rotating reference frame     carrier-interleaving phase shift control     secondary pulsating voltage     beat frequency    

Experimental investigations on operating characteristics of a closed loop pulsating heat pipe

Yu WANG

《能源前沿(英文)》 2015年 第9卷 第2期   页码 134-141 doi: 10.1007/s11708-015-0354-x

摘要: The operating mechanism of the pulsating heat pipe (PHP) is not well understood and the present technology cannot predict required design parameters for a given task. The aim of research work presented in this paper is to better understand the operation regimes of the PHP through experimental investigations. A series of experiments were conducted on a closed loop PHP with 5 turns made of copper capillary tube of 2 mm in inner diameter. Two different working fluids viz. ethanol and acetone were employed. The operating characteristics were studied for the variation of heat input, filling ratio (FR) and inclination angle of the tested device. The results strongly demonstrate the effect of the filling ratio of the working fluid on the operational stability and heat transfer capability of the device. Important insight into the operational characteristics of PHP has been obtained.

关键词: closed loop pulsating heat pipe     thermal performance     operation limit     thermography    

A review of recent experimental investigations and theoretical analyses for pulsating heat pipes

Xin TANG, Lili SHA, Hua ZHANG, Yonglin JU

《能源前沿(英文)》 2013年 第7卷 第2期   页码 161-173 doi: 10.1007/s11708-013-0250-1

摘要: Pulsating heat pipe (PHP), or oscillating heat pipe (OHP), a novel type of highly efficient heat transfer component, has been widely applied in many fields, such as in space-borne two-phase thermal control systems, in the cooling of electronic devices and in energy-saving technology, etc. In the present paper, the characteristics and working principles of the PHPs are introduced and the current researches in the field are described from the viewpoint of experimental tests, theoretical analyses as well as practical applications. Besides, it is found that the state-of-the-art experimental investigations on the PHPs are mainly focused on the flow visualization and the applications of nanofluids and other functional fluids, aiming at enhancing the heat transfer performance of the PHPs. In addition, it is also pointed out that the present theoretical analyses of the PHP are restricted by further development of two-phase flow theories, and are concentrated in the non-linear analyses. Numerical simulations are expected to be another research focus, in particular of the combination of the nanofluids and functional fluids.

关键词: pulsating heat pipe (PHP)     flow visualization     nanofluids     nonlinear analysis    

Parameter identification of interconnected power system frequency after trip-out of high voltage transmission

Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG

《能源前沿(英文)》 2014年 第8卷 第3期   页码 386-393 doi: 10.1007/s11708-014-0323-9

摘要: Accurate modeling and parameters of high voltage (HV) grid are critical for stability research of system frequency. In this paper, simulation modeling of the system frequency was conducted of an interconnected power system with HV transmission lines in China. Based on recorded tripping data of the HV transmission lines, system parameters were identified by using genetic algorithm (GA). The favorable agreement between simulation results and recorded data verifies the validity of gird models and the accuracy of system parameters. The results of this paper can provide reference for the stability research of HV power grid.

关键词: high voltage (HV) grid     frequency stability parameter identification     primary frequency regulation (PFR)    

Recent advances toward high voltage, EC-free electrolytes for graphite-based Li-ion battery

Tong Zhang, Elie Paillard

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 577-591 doi: 10.1007/s11705-018-1758-z

摘要:

Lithium-ion batteries are a key technology in today’s world and improving their performances requires, in many cases, the use of cathodes operating above the anodic stability of state-of-the-art electrolytes based on ethylene carbonate (EC) mixtures. EC, however, is a crucial component of electrolytes, due to its excellent ability to allow graphite anode operation–also required for high energy density batteries–by stabilizing the electrode/electrolyte interface. In the last years, many alternative electrolytes, aiming at allowing high voltage battery operation, have been proposed. However, often, graphite electrode operation is not well demonstrated in these electrolytes. Thus, we review here the high voltage, EC-free alternative electrolytes, focusing on those allowing the steady operation of graphite anodes. This review covers electrolyte compositions, with the widespread use of additives, the change in main lithium salt, the effect of anion (or Li salt) concentration, but also reports on graphite protection strategies, by coatings or artificial solid electrolyte interphase (SEI) or by use of water-soluble binder for electrode processing as these can also enable the use of graphite in electrolytes with suboptimal intrinsic SEI formation ability.

关键词: lithium-ion     electrolyte     solid electrolyte interphase     additives     high voltage     graphite    

Mechanisms for simultaneous ozonation of sulfamethoxazole and natural organic matters in secondary effluent

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1368-0

摘要:

• SMX was mainly degraded by hydrolysis, isoxazole oxidation and double-bond addition.

关键词: Sulfamethoxazole     Ozonation     Natural organic matters     Secondary effluent     Degradation mechanism    

Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

《能源前沿(英文)》 2022年 第16卷 第6期   页码 943-955 doi: 10.1007/s11708-021-0793-5

摘要: This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

关键词: weak grids     voltage source (VS) control     wind turbine (WT)     stabilization control     wind farm     inertial response    

Development and advances in modular multilevel converter based HVDC projects in China

《工程管理前沿(英文)》   页码 183-189 doi: 10.1007/s42524-022-0248-7

摘要: . {{custom_ra.content}} . . . {{article.highlightEn}} . . . {{article.abstractEn}} . . . {{article.authorSummayEn}} . . . . .

关键词: high voltage direct current     power converter     power systems     renewable energy     ultra-high voltage    

Physical and chemical processes of wintertime secondary nitrate aerosol formation

Qi YING

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 348-361 doi: 10.1007/s11783-011-0343-1

摘要: The UCD/CIT model was modified to include a process analysis (PA) scheme for gas and particulate matter (PM) to study the formation of secondary nitrate aerosol during a stagnant wintertime air pollution episode during the California Regional PM /PM Air Quality Study (CRPAQS) where detailed measurements of PM components are available at a few sites. Secondary nitrate is formed in the urban areas from near the ground to a few hundred meters above the surface during the day with a maximum modeled net increase rate of 4 μg·m ·d during the study episode. The secondary nitrate formation rate in rural areas is lower due to lower NO . In the afternoon hours, near-surface temperature can be high enough to evaporate the particulate nitrate. In the nighttime hours, both the gas phase N O reactions with water vapor and the N O heterogeneous reactions with particle-bound water are important for secondary nitrate formation. The N O reactions are most import near the surface to a few hundred meters above surface with a maximum modeled net secondary nitrate increase rate of 1 μg·m ·d and are more significant in the rural areas where the O concentrations are high at night. In general, vertical transport during the day moves the nitrate formed near the surface to higher elevations. During the stagnant days, process analysis indicates that the nitrate concentration in the upper air builds up and leads to a net downward flux of nitrate through vertical diffusion and a rapid increase of surface nitrate concentration.

关键词: secondary nitrate aerosol     N2O5 heterogeneous reaction     process analysis    

Two-echelon Emergency Response Problem and Simulation Considering Secondary Disasters

Han-peng Zhang,Yi Liao,Hui-xia Luo

《工程管理前沿(英文)》 2014年 第1卷 第3期   页码 318-321 doi: 10.15302/J-FEM-2014042

摘要: It is necessary for subsequent resource distribution planning that get expected relief time considering secondary disasters after natural disaster. The goal of this research is to develop a two-echelon emergency resource distribution model under condition of secondary disasters. Taking minimal maximize relief time as criterion of relief performance, we developed response strategies and simulation model to get the expected value. Numerical studies of this paper presented the result of response strategies.

关键词: simulation     secondary disasters     two-echelon vehicle routing model    

Formation of secondary inorganic aerosol in a frigid urban atmosphere

《环境科学与工程前沿(英文)》 2022年 第16卷 第2期 doi: 10.1007/s11783-021-1452-0

摘要:

•Harbin showed relatively high threshold RH (80%) for apparent increase of SOR.

关键词: Haze     Sulfate     Nitrate     Heterogeneous chemistry     Biomass burning     Northeast China    

PCDD/Fs emission, risk characterization, and reduction in China’s secondary copper production industry

Haiqian LI, Yonglong LU, Li LI

《环境科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 589-597 doi: 10.1007/s11783-013-0495-2

摘要: Secondary copper production is one of the key polychlorinated dibenzo- -dioxins and dibenzofurans (PCDD/Fs) emission sources in China, but research and data on this issue are rare. In 2004, when the Stockholm Convention entered into force in China, PCDD/Fs emissions from secondary copper production contributed to 32.2% of the total release. In this paper, PCDD/Fs emission dynamics from secondary copper industry were discussed and cumulative risks were characterized. From 2004 to 2009, industrial policies played an indirect role in PCDD/Fs reduction, but its effects are still limited. The Yangtze River Delta, Pearl River Delta and central regions were among the top three of dioxin emissions from secondary copper production in China. Shanghai, Shandong, Zhejiang, and Jiangxi had comparatively higher accumulated risk and were recommended as the priority regions for promoting PCDD/Fs emission control in China. From 2009 to 2015, the PCDD/Fs emission dynamics in the secondary copper industry were presented through simulation. PCDD/Fs emission equations were established, resulting in the recommendation of control technology conversion rate at 30% for small scale smelters and 51%–57% for large and medium-sized enterprises in 2015. In conclusion, both indirect policy and direct control technology retrofitting should be integrated for more effective PCDD/Fs emission reduction in secondary copper industry.

关键词: polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs)     secondary copper production     emission     risk     China    

Effects of different doses of cadmium on secondary metabolites and gene expression in Artemisia annua

null

《医学前沿(英文)》 2017年 第11卷 第1期   页码 137-146 doi: 10.1007/s11684-016-0486-3

摘要:

This study aims to elucidate the underlying molecular mechanisms of artemisinin accumulation induced by cadmium (Cd). The effects of different Cd concentrations (0, 20, 60, and 120 μmol/L) on the biosynthesis of Artemisia annua L. were examined. Intermediate and end products were quantified by HPLC-ESI-MS/MS analysis. The expression of key biosynthesis enzymes was also determined by qRT-PCR. The results showed that the application of treatment with 60 and 120 μmol/L Cd for 3 days significantly improved the biosynthesis of artemisinic acid, arteannuin B, and artemisinin. The concentrations of artemisinic acid, arteannuin B, and artemisinin in the 120 μmol/L Cd-treated group were 2.26, 102.08, and 33.63 times higher than those in the control group, respectively. The concentrations of arteannuin B and artemisinin in 60 μmol/L Cd-treated leaves were 61.10 and 26.40 times higher than those in the control group, respectively. The relative expression levels of HMGRFPSADSCYP71AV1DBR2ALDH1, and DXR were up-regulated in the 120 μmol/L Cd-treated group because of increased contents of artemisinic metabolites after 3 days of treatment. Hence, appropriate doses of Cd can increase the concentrations of artemisinic metabolites at a certain time point by up-regulating the relative expression levels of key enzyme genes involved in artemisinin biosynthesis.

关键词: Cd     secondary metabolites     gene expressions     Artemisia annua L.    

Cluster voltage control method for “Whole County” distributed photovoltaics based on improved differential

《能源前沿(英文)》   页码 782-795 doi: 10.1007/s11708-023-0905-8

摘要: China is vigorously promoting the “whole county promotion” of distributed photovoltaics (DPVs). However, the high penetration rate of DPVs has brought problems such as voltage violation and power quality degradation to the distribution network, seriously affecting the safety and reliability of the power system. The traditional centralized control method of the distribution network has the problem of low efficiency, which is not practical enough in engineering practice. To address the problems, this paper proposes a cluster voltage control method for distributed photovoltaic grid-connected distribution network. First, it partitions the distribution network into clusters, and different clusters exchange terminal voltage information through a “virtual slack bus.” Then, in each cluster, based on the control strategy of “reactive power compensation first, active power curtailment later,” it employs an improved differential evolution (IDE) algorithm based on Cauchy disturbance to control the voltage. Simulation results in two different distribution systems show that the proposed method not only greatly improves the operational efficiency of the algorithm but also effectively controls the voltage of the distribution network, and maximizes the consumption capacity of DPVs based on qualified voltage.

关键词: distributed photovoltaics (DPVs)     cluster partitioning     improved differential evolution algorithm     voltage control     consumption capacity of distributed photovoltaics    

Simple model of sludge thickening process in secondary settlers

Yuankai ZHANG,Hongchen WANG,Lu QI,Guohua LIU,Zhijiang HE,Songzhu JIANG

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 319-326 doi: 10.1007/s11783-014-0758-6

摘要: In wastewater treatment plants (WWTPs), a secondary settler acts as a clarifier, sludge thickener, and sludge storage tank during peak flows and therefore plays an important role in the performance of the activated sludge process. Sludge thickening occurs in the lower portions of secondary clarifiers during their operation. In this study, by detecting the hindered zone from the complete thickening process of activated sludge, a simple model for the sludge thickening velocity, , describing the potential and performance of activated sludge thickening in the hindered zone was developed. However, sludge thickening in the compression zone was not studied because sludge in the compression zone showed limited thickening. This empirical model was developed using batch settling data obtained from four WWTPs and validated using measured data from a fifth WWTP to better study sludge thickening. To explore different sludge settling and thickening mechanisms, the curves of sludge thickening and sludge settling were compared. Finally, it was found that several factors including temperature, stirring, initial depth, and polymer conditioning can lead to highly concentrated return sludge and biomass in a biologic reactor.

关键词: wastewater treatment plants     secondary settler     sludge thickening     sludge settling     hindered zone    

标题 作者 时间 类型 操作

Solid-state transformer-based new traction drive system and control

Jianghua FENG, Jing SHANG, Zhixue ZHANG, Huadong LIU, Zihao HUANG

期刊论文

Experimental investigations on operating characteristics of a closed loop pulsating heat pipe

Yu WANG

期刊论文

A review of recent experimental investigations and theoretical analyses for pulsating heat pipes

Xin TANG, Lili SHA, Hua ZHANG, Yonglin JU

期刊论文

Parameter identification of interconnected power system frequency after trip-out of high voltage transmission

Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG

期刊论文

Recent advances toward high voltage, EC-free electrolytes for graphite-based Li-ion battery

Tong Zhang, Elie Paillard

期刊论文

Mechanisms for simultaneous ozonation of sulfamethoxazole and natural organic matters in secondary effluent

期刊论文

Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

期刊论文

Development and advances in modular multilevel converter based HVDC projects in China

期刊论文

Physical and chemical processes of wintertime secondary nitrate aerosol formation

Qi YING

期刊论文

Two-echelon Emergency Response Problem and Simulation Considering Secondary Disasters

Han-peng Zhang,Yi Liao,Hui-xia Luo

期刊论文

Formation of secondary inorganic aerosol in a frigid urban atmosphere

期刊论文

PCDD/Fs emission, risk characterization, and reduction in China’s secondary copper production industry

Haiqian LI, Yonglong LU, Li LI

期刊论文

Effects of different doses of cadmium on secondary metabolites and gene expression in Artemisia annua

null

期刊论文

Cluster voltage control method for “Whole County” distributed photovoltaics based on improved differential

期刊论文

Simple model of sludge thickening process in secondary settlers

Yuankai ZHANG,Hongchen WANG,Lu QI,Guohua LIU,Zhijiang HE,Songzhu JIANG

期刊论文