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A numerical study of non-Darcy flow in EGS heat reservoirs during heat extraction

Wenjiong CAO, Wenbo HUANG, Guoling WEI, Yunlong JIN, Fangming JIANG

《能源前沿(英文)》 2019年 第13卷 第3期   页码 439-449 doi: 10.1007/s11708-019-0612-4

摘要: Underground non-Darcy fluid flow has been observed and investigated for decades in the petroleum industry. It is deduced by analogy that the fluid flow in enhanced geothermal system (EGS) heat reservoirs may also be in the non-Darcy regime under some conditions. In this paper, a transient 3D model was presented, taking into consideration the non-Darcy fluid flow in EGS heat reservoirs, to simulate the EGS long-term heat extraction process. Then, the non-Darcy flow behavior in water- and supercritical CO (SCCO )-based EGSs was simulated and discussed. It is found that non-Darcy effects decrease the mass flow rate of the fluid injected and reduce the heat extraction rate of EGS as a flow resistance in addition to the Darcy resistance which is imposed to the seepage flow in EGS heat reservoirs. Compared with the water-EGS, the SCCO -EGS are more prone to experiencing much stronger non-Darcy flow due to the much larger mobility of the SCCO . The non-Darcy flow in SCCO - EGSs may thus greatly reduce their heat extraction performance. Further, a criterion was analyzed and proposed to judge the onset of the non-Darcy flow in EGS heat reservoirs. The fluid flow rate and the initial thermal state of the reservoir were taken and the characteristic Forchheimer number of an EGS was calculated. If the calculated Forchheimer number is larger than 0.2, the fluid flow in EGS heat reservoirs experiences non-negligible non-Darcy flow characteristic.

关键词: enhanced geothermal system     non-Darcy flow     heat extraction     Reynolds number     Forchheimer number    

Flow behavior of non-spherical particle flowing in hopper

He TAO,Wenqi ZHONG,Baosheng JIN

《能源前沿(英文)》 2014年 第8卷 第3期   页码 315-321 doi: 10.1007/s11708-014-0331-9

摘要: Ellipsoidal particles flowing in the hopper were simulated by using the discrete element method (DEM), and described by the multi-element method. The contact detection algorithm and equations for ellipsoidal particle motion in hopper were developed. And the simulation results were confirmed by experiment. Additionally, the mass flow rate, pressure distribution and velocity distribution of two kinds of particles were examined. The results show that the mass flow rate of ellipsoidal particles is smaller than that of spherical particles. There is a maximum value of pressure drop at the top of the junction. Besides, the pressure drop decreases with the discharging time increasing. The velocity of spherical particle is larger than that of ellipsoidal.

关键词: discrete element method     ellipsoidal particle     flow behavior     hopper    

基于非关联流动法则的滑移线场及上限法研究

郑颖人,邓楚键,王敬林

《中国工程科学》 2010年 第12卷 第8期   页码 56-69

摘要:

当前岩土材料的滑移线场理论及上限法中都广泛采用经典塑性理论中的关联流动法则,由此得出应力特征线与速度滑移线一致的结论。而试验得知,岩土材料并不服从关联流动法则,因而应力特征线与速度滑移线不可能重合。文章分析了基于关联流动法则的滑移线场及上限法中存在的问题,根据广义塑性理论推导了基于非关联流动法则的滑移线场及上限法,消除了现行滑移线场理论及上限法理论中的种种矛盾。

关键词: 滑移线场     上限法     关联流动法则     非关联流动法则     广义塑性理论    

Application of a weakly compressible smoothed particle hydrodynamics multi-phase model to non-cohesiveembankment breaching due to flow overtopping

Rasoul MEMARZADEH, Gholamabbas BARANI, Mahnaz GHAEINI-HESSAROEYEH

《结构与土木工程前沿(英文)》 2018年 第12卷 第3期   页码 412-424 doi: 10.1007/s11709-017-0432-8

摘要:

The subject of present study is the application of mesh free Lagrangian two-dimensional non-cohesive sediment transport model applied to a two-phase flow over an initially trapezoidal-shaped sediment embankment. The governing equations of the present model are the Navier-Stocks equations solved using Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) method. To simulate the movement of sediment particles, the model considers a powerful two-part technique; when the sediment phase has rigid behavior, only the force term due to shear stress in the Navier-Stokes equations is used for simulation of sediment particles’ movement. Otherwise, all the Navier-Stokes force terms are used for transport simulation of sediment particles. In the present model, the interactions between different phases are calculated automatically, even with considerable difference between the density and viscosity of phases. Validation of the model is performed using simulation of available laboratory experiments, and the comparison between computational results and experimental data shows that the model generally predicts well the flow propagation over movable beds, the induced sediment transport and bed changes, and temporal evolution of embankment breaching.

关键词: WCSPH method     non-cohesive sediment transport     rheological model     two-part technique     two-phase dam break    

REDUCTION OF NON-POINT SOURCE POLLUTION IN THE YONG’AN RIVER BY CONSTRUCTED WETLAND BASED ON 9 YEARS

《农业科学与工程前沿(英文)》 2023年 第10卷 第4期   页码 627-638 doi: 10.15302/J-FASE-2023516

摘要:

The agricultural and livestock activities surrounding the rivers flowing into the lakes have caused non-point source pollution, leading to excessive amounts of nutrient salts in downstream rivers. Introducing river water into constructed wetlands along river course has proven to be an effective solution for decreasing nitrogen (N) and phosphorus (P) loads. This paper reports 9 years of monitoring the Yong’an River and its surrounding constructed wetlands in the upper reaches of Erhai Lake, located in Yunnan Province, China. This study analyzed the main types of pollutants in the river, and evaluated the removal efficiency of pollutants by the constructed wetlands. The findings indicate that total nitrogen (TN) and nitrate nitrogen (NO3-N) are the primary pollutants in the Yong’an River, which exhibit variation throughout the year corresponding to the alternating wet and dry seasons. Although constructed wetlands are effective in removing NO3-N and P, their efficacy in removing ammonium nitrogen (NH4+-N) and organic pollutants is limited. This limitation can be attributed to the lack of timely disposal of aquatic plant residues. This research contributes to the understanding of the potential issues that may arise during the extended use of constructed wetlands and provides solutions to address them.

关键词: inflowing rivers     surface-flow constructed wetland     nutrients     long-term monitoring    

超声血流的无创伤检测和医学信号的特征提取

王威琪,汪源源,余建国,吴晓峰,刘斌,张羽,陈斯中,仪艳华,邵谦明

《中国工程科学》 2001年 第3卷 第2期   页码 52-64

摘要:

人体信号是随机性和背景噪声都很强的复杂信号。文章首先研究了利用超声Doppler技术定量检测血流速度的方法,然后将一些现代信息处理中的新理论、新方法引入医学超声的信息处理,为医学超声信息的特征提取提供了新的手段。这些理论包括:分形、数学形态学、数量化、小波变换、极点轨迹和血管传输线模型等。文章最后阐述了利用上述新方法作为技术核心而研制的三套应用系统;肺动脉血液动力学参数的无损估测系统、彩色编码的声谱系统和超声血流定量检测系统。

关键词: 超声血流     医学信号     无创伤检测     特征提取    

Discrete element method modeling of corn-shaped particle flow in rectangular hopper

He TAO, Baosheng JIN, Wenqi ZHONG, Xiaofang WANG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 267-275 doi: 10.1007/s11709-010-0035-0

摘要: Discrete element method (DEM) was developed to simulate the corn-shaped particles flow in the hopper. The corn-shaped particle was described by four overlapping spheres. Contact force and gravity force were considered when establishing the model. In addition, flowing characteristic of particles in the hopper was studied. The effect of friction coefficient on the wall pressure, voidage and velocity distribution was analyzed. The results show that the discharge rate decreases with the friction coefficient increasing; and the “over-pressure” phenomenon occurs in the discharging process for two different friction coefficients. The voidage also increases as the friction coefficient increasing. And the velocity distribution is more uniformity and is closer to the mass flow with the friction coefficient deceasing.

关键词: discrete         element          method         (DEM)             non-spherical     voidage     pressure     velocity distribution     hopper    

theoretical study of microwave enhanced catalytic hydrodesulfurization of thiophene in a continuous-flow

Hui Shang, Pengfei Ye, Yude Yue, Tianye Wang, Wenhui Zhang, Sainab Omar, Jiawei Wang

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 744-758 doi: 10.1007/s11705-019-1839-7

摘要: Hydrodesulfurization (HDS) of thiophene, as a gasoline model oil, over an industrial Ni-Mo/Al O catalyst was investigated in a continuous system under microwave irradiation. The HDS efficiency was much higher (5%‒14%) under microwave irradiation than conventional heating. It was proved that the reaction was enhanced by both microwave thermal and non-thermal effects. Microwave selective heating caused hot spots inside the catalyst, thus improved the reaction rate. From the analysis of the non-thermal effect, the molecular collisions were significantly increased under microwave irradiation. However, instead of being reduced, the apparent activation energy increased. This may be due to the microwave treatment hindering the adsorption though upright S-bind (η ) and enhancing the parallel adsorption (η ), both adsorptions were considered to favor to the direct desulfurization route and the hydrogenation route respectively. Therefore, the HDS process was considered to proceed along the hydrogenation route under microwave irradiation.

关键词: thiophene     microwave irradiation     hydrodesulfurization     non-thermal microwave effect    

Numerical study of internal flow field and flow passage improvement of an inlet particle separator

Florian PAOLI, Tong WANG

《能源前沿(英文)》 2011年 第5卷 第4期   页码 386-397 doi: 10.1007/s11708-011-0156-8

摘要: By performing gas flow field numerical simulations for several inlet Reynolds numbers (from 2 × 10 to 9 × 10 ) and byflow ratios (from 10% to 20%), the present study has proposed to improve the flow passage of an inlet particle separator. An adjacent objective of the study is to lower pressure losses of the inlet particle separator (IPS). No particle has been included in the gas flow for a -epsilon turbulence model. The velocity distribution in different sections and the pressure coefficient along the duct have been analyzed, which indicates that there exist important low-velocity regions and vortices in the separation area. Therefore, the profile of streamlines along the original passage has been considered. This profile illustrated a vacuum region in the same area. All investigations suggest that the separation area is the most critical one for fulfilling the objective on pressure losses limitation. Then the flow passage improvement method has focused on the separation area. An improved shape has been designed in order to suit smoothly to the streamlines in this region. Similar numerical studies as those for the original shape have been conducted on this improved shape, confirming some considerable enhancements compared with the original shape. The significant vortices which appear in the original shape reduce in amount and size. Besides, pressure losses are greatly decreased in both outlets (up to 30% for high Reynolds number) and the flow is uniform at the main outlet. Subsequent engineering surveys could rely on expressions obtained for in both outlets which extend the pressure losses for a wide range of inlet Reynolds numbers. As a result, the numerical calculations demonstrate that the flow passage improvement method applied in this study has succeeded in designing a shape which enhances the flow behavior.

关键词: streamlines     pressure losses     flow passage improvement     inlet particle separator (IPS)    

Bevacizumab in combination with pemetrexed and platinum for elderly patients with advanced non-squamousnon-small-cell lung cancer: a retrospective analysis

《医学前沿(英文)》 2022年 第16卷 第4期   页码 610-617 doi: 10.1007/s11684-021-0827-8

摘要: Bevacizumab, an anti-VEGF monoclonal antibody, has significantly improved the clinical outcomes of patients with advanced non-squamous NSCLC (ns-NSCLC). However, the safety and efficacy of bevacizumab for elderly patients with advanced NSCLC require further investigation. Thus, 59 patients were included in the present retrospective study, 22 patients in the bevacizumab plus pemetrexed and platinum (B+PP) group, and 37 patients in the pemetrexed and platinum (PP) group. For the entire cohort of patients, the median OS was 33.3 months, and the 1-year and 2-year overall survival rates were 88.5% and 67.8%, respectively. The median OS and 1-year and 2-year OS rates were 20.5 months, 70.3% and 0%, respectively, in the B+PP group and 33.4 months, 97.0% and 89.4%, respectively, in the PP group (P <0.001). The incidence of grade≥3 adverse events was higher in the B+PP group than in the PP group (27.3% vs. 10.8%, respectively; P=0.204). Univariate and multivariate analyses suggested that the receipt of≥5 cycles of first-line chemotherapy was an independent favorable prognostic factor for OS, whereas the addition of bevacizumab was an unfavorable prognostic factor. With increased toxicities, the addition of bevacizumab to PP does not improve the overall survival of elderly patients with advanced ns-NSCLC.

关键词: bevacizumab     elderly patient     advanced non-small-cell lung cancer     overall survival     toxicity    

物质流分析的跟踪观察法

陆钟武

《中国工程科学》 2006年 第8卷 第1期   页码 18-25

摘要:

流动,是物质(如铜、铝等)流动和流体流动二者所具有的基本特征,基于这个论点,简要地回顾了流体力学中研究流体流动的两种方法,即拉格朗日法和欧拉法;相应地提出了物质流分析的两种方法,即跟踪观察法和定点观察法。由于前者在文献中未见报道,因此对它进行了重点说明。强调了物质流的跟踪观察法既适用于稳态物质流(产品产量不变),也适用于非稳态物质流(产品产量增长或下降)。以钢铁产品生命周期的铁流图为例,说明了物质流的跟踪模型。在引入了物质流的非稳度后,提出了物质流各项指标的计算式,以及它们之间的相互关系。以瑞典铅酸电池系统为对象,计算了其中铅流的各项指标,并进行了必要的分析。

关键词: 物质流的研究方法     物质流的跟踪观察法     物质流的基本公式     物质流的非稳度    

UPFC setting to avoid active power flow loop considering wind power uncertainty

Shenghu LI, Ting WANG

《能源前沿(英文)》 2023年 第17卷 第1期   页码 165-175 doi: 10.1007/s11708-020-0686-z

摘要: The active power loop flow (APLF) may be caused by impropriate network configuration, impropriate parameter settings, and/or stochastic bus powers. The power flow controllers, e.g., the unified power flow controller (UPFC), may be the reason and the solution to the loop flows. In this paper, the critical existence condition of the APLF is newly integrated into the simultaneous power flow model for the system and UPFC. Compared with the existing method of alternatively solving the simultaneous power flow and sensitivity-based approaching to the critical existing condition, the integrated power flow needs less iterations and calculation time. Besides, with wind power fluctuation, the interval power flow (IPF) is introduced into the integrated power flow, and solved with the affine Krawcyzk iteration to make sure that the range of active power setting of the UPFC not yielding the APLF. Compared with Monte Carlo simulation, the IPF has the similar accuracy but less time.

关键词: active power loop flow (APLF)     unified power flow controller (UPFC)     wind power uncertainty     interval power flow (IPF)    

A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

《环境科学与工程前沿(英文)》 2023年 第18卷 第4期 doi: 10.1007/s11783-024-1800-y

摘要:

● A spindle-shaped influent chamber was designed and equipped in FCDI system.

关键词: Spindle-shaped chamber     Desalination performance     Flow electrode capacitive deionization    

Simulation of horizontal slug-flow pneumatic conveying with kinetic theory

GU Zhengmeng, GUO Liejin

《能源前沿(英文)》 2007年 第1卷 第3期   页码 336-340 doi: 10.1007/s11708-007-0050-6

摘要: Wavelike slug-flow is a representative flow type in horizontal pneumatic conveying. Kinetic theory was introduced to establish a 3D kinetic numerical model for wavelike slug gas-solid flow in this paper. Wavelike motion of particulate slugs in horizontal pipes was numerically investigated. The formation and motion process of slugs and settled layer were simulated. The characteristics of the flow, such as pressure drop, air velocity distribution, slug length and settled layer thickness, and the detailed changing characteristics of slug length and settled layer thickness with air velocity were obtained. The results indicate that kinetic theory can represent the physical characteristics of the non-suspension dense phase flow of wavelike slug pneumatic conveying. The experiment in this paper introduced a new idea for the numerical calculation of slug-flow pneumatic conveying.

关键词: velocity distribution     detailed     slug-flow     gas-solid     theory    

Characterization and comparison of organic functional groups effects on electrolyte performance for vanadium redox flow

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1221-1230 doi: 10.1007/s11705-023-2298-8

摘要: The vanadium redox flow battery with a safe and capacity-controllable large-scale energy storage system offers a new method for the sustainability. In this case, acetic acid, methane sulfonic acid, sulfonic acid, amino methane sulfonic acid, and taurine are used to overcome the low electrolyte energy density and stability limitations, as well as to investigate the effects of various organic functional groups on the vanadium redox flow battery. When compared to the pristine electrolyte (0.22 Ah, 5.0 Wh·L–1, 85.0%), the results show that taurine has the advantage of maintaining vanadium ion concentrations, discharge capacity (1.43 Ah), energy density (33.9 Wh·L–1), and energy efficiency (90.5%) even after several cycles. The acetic acid electrolyte is more conducive to the low-temperature stability of the V(II) electrolyte (177 h at −25 °C) than pristine (82 h at −2 °C). The –SO3H group, specifically the coaction of the –NH2 and –SO3H groups, improves electrolyte stability. The –NH2 and –COOH additive groups improved conductivity and electrochemical activity.

关键词: vanadium redox flow battery     functional groups     organic additives     energy density     stability    

标题 作者 时间 类型 操作

A numerical study of non-Darcy flow in EGS heat reservoirs during heat extraction

Wenjiong CAO, Wenbo HUANG, Guoling WEI, Yunlong JIN, Fangming JIANG

期刊论文

Flow behavior of non-spherical particle flowing in hopper

He TAO,Wenqi ZHONG,Baosheng JIN

期刊论文

基于非关联流动法则的滑移线场及上限法研究

郑颖人,邓楚键,王敬林

期刊论文

Application of a weakly compressible smoothed particle hydrodynamics multi-phase model to non-cohesiveembankment breaching due to flow overtopping

Rasoul MEMARZADEH, Gholamabbas BARANI, Mahnaz GHAEINI-HESSAROEYEH

期刊论文

REDUCTION OF NON-POINT SOURCE POLLUTION IN THE YONG’AN RIVER BY CONSTRUCTED WETLAND BASED ON 9 YEARS

期刊论文

超声血流的无创伤检测和医学信号的特征提取

王威琪,汪源源,余建国,吴晓峰,刘斌,张羽,陈斯中,仪艳华,邵谦明

期刊论文

Discrete element method modeling of corn-shaped particle flow in rectangular hopper

He TAO, Baosheng JIN, Wenqi ZHONG, Xiaofang WANG,

期刊论文

theoretical study of microwave enhanced catalytic hydrodesulfurization of thiophene in a continuous-flow

Hui Shang, Pengfei Ye, Yude Yue, Tianye Wang, Wenhui Zhang, Sainab Omar, Jiawei Wang

期刊论文

Numerical study of internal flow field and flow passage improvement of an inlet particle separator

Florian PAOLI, Tong WANG

期刊论文

Bevacizumab in combination with pemetrexed and platinum for elderly patients with advanced non-squamousnon-small-cell lung cancer: a retrospective analysis

期刊论文

物质流分析的跟踪观察法

陆钟武

期刊论文

UPFC setting to avoid active power flow loop considering wind power uncertainty

Shenghu LI, Ting WANG

期刊论文

A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

期刊论文

Simulation of horizontal slug-flow pneumatic conveying with kinetic theory

GU Zhengmeng, GUO Liejin

期刊论文

Characterization and comparison of organic functional groups effects on electrolyte performance for vanadium redox flow

期刊论文