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Unconventional hydrodynamics of hybrid fluid made of liquid metals and aqueous solution under appliedfields

Xu-Dong ZHANG, Yue SUN, Sen CHEN, Jing LIU

《能源前沿(英文)》 2018年 第12卷 第2期   页码 276-296 doi: 10.1007/s11708-018-0545-3

摘要: The hydrodynamic characteristics of hybrid fluid made of liquid metal/aqueous solution are elementary in the design and operation of conductive flow in a variety of newly emerging areas such as chip cooling, soft robot, and biomedical practices. In terms of physical and chemical properties, such as density, thermal conductivity and electrical conductivity, their huge differences between the two fluidic phases remain a big challenge for analyzing the hybrid flow behaviors. Besides, the liquid metal immersed in the solution can move and deform when administrated with non-contact electromagnetic force, or even induced by redox reaction, which is entirely different from the cases of conventional contact force. Owing to its remarkable capability in flow and deformation, liquid metal immersed in the solution is apt to deform on an extremely large scale, resulting in marked changes on its boundary and interface. However, the working mecha- nisms of the movement and deformation of liquid metal lack appropriate models to describe such scientific issues via a set of well-established unified equations. To promote investigations in this important area, the present paper is dedicated to summarizing this unconventional hydrodynamics from experiment, theory, and simulation. Typical experimental phenomena and basic working mechanisms are illustrated, followed by the movement and deformation theories to explain these phenomena. Several representative simulation methods are then proposed to tackle the governing functions of the electrohydrodynamics. Finally, prospects and challenges are raised, offering an insight into the new physics of the hybrid fluid under applied fields.

关键词: liquid metal     hybrid fluid     hydrodynamics     surface tension     applied fields     self-actuation    

Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

《结构与土木工程前沿(英文)》 2015年 第9卷 第2期   页码 114-120 doi: 10.1007/s11709-014-0267-5

摘要: The accurate and efficient simulation of random heterogeneous media is important in the framework of modeling and design of complex materials across multiple length scales. It is usually assumed that the morphology of a random microstructure can be described as a non-Gaussian random field that is completely defined by its multivariate distribution. A particular kind of non-Gaussian random fields with great practical importance is that of translation fields resulting from a simple memory-less transformation of an underlying Gaussian field with known second-order statistics. This paper provides a critical examination of existing random field models of heterogeneous two-phase media with emphasis on level-cut random fields which are a special case of translation fields. The case of random level sets, often used to represent the geometry of physical systems, is also examined. Two numerical examples are provided to illustrate the basic features of the different approaches.

关键词: microstructure     random fields     level sets     shape recovery     two-phase media    

NITROGEN USE AND MANAGEMENT IN ORCHARDS AND VEGETABLE FIELDS IN CHINA: CHALLENGES AND SOLUTIONS

《农业科学与工程前沿(英文)》 2022年 第9卷 第3期   页码 386-395 doi: 10.15302/J-FASE-2022443

摘要:

● Excessive application of N fertilizers in orchards and vegetable fields (OVFs) in China is particularly common.

关键词: nitrogen fate     nitrogen fertilizer     orchards     vegetable fields    

Coordinate system applied to magnetic suspension project between Shanghai and Hangzhou

SHI Yimin, WANG Lihua, LUO Yan

《结构与土木工程前沿(英文)》 2008年 第2卷 第3期   页码 288-292 doi: 10.1007/s11709-008-0041-7

摘要: In order to satisfy the requirement for route location of a magnetic suspension project between Shanghai and Hangzhou, this paper proposes to adopt a new form of geodetic coordinate system, which is defined by meridians and parallel circles but with two coordinate parameters expressed by length. Not only the coordinate systems for route location along the whole line can be unified, but also the precision of lengths and angles obtained from simple formulas are very high and there are not any map projection distortions. This has been proven by calculation.

关键词: requirement     projection     calculation     Shanghai     precision    

Advanced biomass materials: progress in the applications for energy, environmental, and emerging fields

《化学科学与工程前沿(英文)》 2023年 第17卷 第7期   页码 795-797 doi: 10.1007/s11705-023-2336-6

摘要: Advanced biomass materials: progress in the applications for energy, environmental, and emerging fields

关键词: progress applications energy     fields    

Engineering Fronts in fields of Energy and Electrical Science and Technologies in the report of

《能源前沿(英文)》 2023年 第17卷 第1期   页码 5-8 doi: 10.1007/s11708-023-0868-6

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The perturbed magnetic fields caused by mechanical stress

QIN Fei, YAN Dong-mei

《机械工程前沿(英文)》 2006年 第1卷 第2期   页码 151-156 doi: 10.1007/s11465-006-0015-1

摘要: In the framework of the linearized magnetoelastic theory, the perturbed magnetic fields caused by mechanical stress and deformation were investigated theoretically. Governing equations and boundary conditions to determine the perturbed fields were derived. The effect of mechanical deformation on the magnetic fields was taken into account by coupling structural displacement into the perturbed magnetic field continuous conditions on the boundary of the structure. As an example, the perturbed field of a half-plane magnetized structure caused by a point force was calculated by the Fourier transform method. The results show that the calculated magnetic intensity component normal to the boundary of the structure reaches its maximum at the point force acted while the component tangent to the boundary inverses its direction sharply. The magnetic induction of the perturbed field is proportional to the applied force. Magnitude analysis proved that since the applied magnetic field has a relative weak intensity such as the Earth s magnetic field, influence of the magnetic field on deformation of the structure can be neglected.

Stem cell niches and endogenous electric fields in tissue repair

null

《医学前沿(英文)》 2011年 第5卷 第1期   页码 40-44 doi: 10.1007/s11684-011-0108-z

摘要:

Adult stem cells are responsible for homeostasis and repair of many tissues. Endogenous adult stem cells reside in certain regions of organs, known as the stem cell niche, which is recognized to have an important role in regulating tissue maintenance and repair. In wound healing and tissue repair, stem cells are mobilized and recruited to the site of wound, and participate in the repair process. Many regulatory factors are involved in the stem cell-based repair process, including stem cell niches and endogenous wound electric fields, which are present at wound tissues and proved to be important in guiding wound healing. Here we briefly review the role of stem cell niches and endogenous electric fields in tissue repair, and hypothesize that endogenous electric fields become part of stem cell niche in the wound site.

关键词: stem cell     stem cell niche     electric field     tissue repair    

Characterization of random stress fields obtained from polycrystalline aggregate calculations using multi-scale

Bruno SUDRET,Hung Xuan DANG,Marc BERVEILLER,Asmahana ZEGHADI,Thierry YALAMAS

《结构与土木工程前沿(英文)》 2015年 第9卷 第2期   页码 121-140 doi: 10.1007/s11709-015-0290-1

摘要: The spatial variability of stress fields resulting from polycrystalline aggregate calculations involving random grain geometry and crystal orientations is investigated. A periodogram-based method is proposed to identify the properties of homogeneous Gaussian random fields (power spectral density and related covariance structure). Based on a set of finite element polycrystalline aggregate calculations the properties of the maximal principal stress field are identified. Two cases are considered, using either a fixed or random grain geometry. The stability of the method w.r.t the number of samples and the load level (up to 3.5% macroscopic deformation) is investigated.

关键词: polycrystalline aggregates     crystal plasticity     random fields     spatial variability     correlation structure    

Decomposition analysis applied to energy and emissions: A literature review

《工程管理前沿(英文)》   页码 625-639 doi: 10.1007/s42524-023-0270-4

摘要: Decomposition analysis has been widely used to assess the determinants of energy and CO2 emissions in academic research and policy studies. Both the methodology and application of decomposition analysis have been largely improved in the past decades. After more than 50 years’ developments, decomposition studies have become increasingly sophisticated and diversified, and tend to converge internally and integrate with other analytical approaches externally. A good understanding of the literature and state of the art is critical to identify knowledge gaps and formulate future research agenda. To this end, this study presents a literature survey for decomposition analysis applied to energy and emission issues, with a focus on the period of 2016–2021. A review for three individual decomposition techniques is first conducted, followed by a synthesis of emerging trends and features for the decomposition analysis literature as a whole. The findings are expected to direct future research in decomposition analysis.

关键词: index decomposition analysis     structural decomposition analysis     production decomposition analysis     energy     CO2 emissions    

Modeling water and heat transfer in soil-plant-atmosphere continuum applied to maize growth under plastic

Meng DUAN, Jin XIE, Xiaomin MAO

《农业科学与工程前沿(英文)》 2019年 第6卷 第2期   页码 144-161 doi: 10.15302/J-FASE-2019258

摘要:

Based on our previous work modeling crop growth (CropSPAC) and water and heat transfer in the soil-plant-atmosphere continuum (SPAC), the model was improved by considering the effect of plastic film mulching applied to field-grown maize in North-west China. In CropSPAC, a single layer canopy model and a multi-layer soil model were adopted to simulate the energy partition between the canopy and water and heat transfer in the soil, respectively. The maize growth module included photosynthesis, growth stage calculation, biomass accumulation, and participation. The CropSPAC model coupled the maize growth module and SPAC water and heat transfer module through leaf area index (LAI), plant height and soil moisture condition in the root zone. The LAI and plant height were calculated from the maize growth module and used as input for the SPAC water and heat transfer module, and the SPAC module output for soil water stress conditions used as an input for maize growth module. We used , the representation of evaporation resistance, instead of the commonly used evaporation resistance to reflect the change of latent heat flux of soil evaporation under film mulching as well as the induced change in energy partition. The model was tested in a maize field at Yingke irrigation area in North-west China. Results showed reasonable agreement between the simulations and measurements of LAI, above-ground biomass and soil water content. Compared with the original model, the modified model was more reliable for maize growth simulation under film mulching and showed better accuracy for the LAI (with the coefficient of determination = 0.92, the root mean square of error RMSE= 1.23, and the Nush-Suttclife efficiency E = 0.87), the above-ground biomass (with = 0.96, RMSE= 7.17 t·ha and E = 0.95) and the soil water content in 0–1 m soil layer (with = 0.78, RMSE= 49.44 mm and E = 0.26). Scenarios were considered to simulate the influence of future climate change and film mulching on crop growth, soil water and heat conditions, and crop yield. The simulations indicated that the change of LAI, leaf biomass and yield are negatively correlated with temperature change, but the growing degree-days, evaporation, soil water content and soil temperature are positively correlated with temperature change. With an increase in the ratio of film mulching area, the evaporation will decrease, while the impact of film mulching on crop transpiration is not significant. In general, film mulching is effective in saving water, preserving soil moisture, increasing soil surface temperature, shortening the potential growth period, and increasing the potential yield of maize.

关键词: film mulching     growth stage     leaf area index     maize growth     water and heat transfer    

Extrapolation reconstruction of wind pressure fields on the claddings of high-rise buildings

Yehua SUN, Guquan SONG, Hui LV

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 653-666 doi: 10.1007/s11709-018-0503-5

摘要: Recent research about reconstruction methods mainly used the interpolation reconstruction of the fluctuating wind pressure field on the surface. However, to investigate wind pressure at the edge of the building, the work presented in this paper focuses on the extrapolation reconstruction of wind pressure fields. Here, we propose an improved proper orthogonal decomposition (POD) and Kriging method with a von Kármán correlation function to resolve this issue. The studies show that it works well for not only interpolation reconstruction but also extrapolation reconstruction. The proposed method does require determination of the Hurst exponent and other parameters analysed from the original data. Hence, the fluctuating wind fields have been characterized by the von Kármán correlation function, as an a priori function. Compared with the cubic spline method and different variogram, preliminary results suggest less time consumption and high efficiency in extrapolation reconstruction at the edge.

关键词: extrapolation reconstruction     proper orthogonal decomposition     Kriging method     von Kármán function     Hurst exponent     rescaled range analysis    

Preliminary design of an SCO conversion system applied to the sodium cooled fast reactor

《能源前沿(英文)》 2021年 第15卷 第4期   页码 832-841 doi: 10.1007/s11708-021-0777-5

摘要: The supercritical carbon dioxide (SCO2) Brayton cycle has become an ideal power conversion system for sodium-cooled fast reactors (SFR) due to its high efficiency, compactness, and avoidance of sodium-water reaction. In this paper, the 1200 MWe large pool SFR (CFR1200) is used as the heat source of the system, and the sodium circuit temperature and the heat load are the operating boundaries of the cycle system. The performance of different SCO2 Brayton cycle systems and changes in key equipment performance are compared. The study indicates that the inter-stage cooling and recompression cycle has the best match with the heat source characte-ristics of the SFR, and the cycle efficiency is the highest (40.7%). Then, based on the developed system transient analysis program (FR-Sdaso), a pool-type SFR power plant system analysis model based on the inter-stage cooling and recompression cycle is established. In addition, the matching between the inter-stage cooling recompression cycle and the SFR during the load cycle of the power plant is studied. The analysis shows that when the nuclear island adopts the flow-advanced operation strategy and the carbon dioxide flowrate in the SCO2 power conversion system is adjusted with the goal of maintaining the sodium-carbon dioxide heat exchanger sodium side outlet temperature unchanged, the inter-stage cooling recompression cycle can match the operation of the SFR very well.

关键词: sodium-cooled fast reactor (SFR)     supercritical carbon dioxide (SCO2)     brayton cycle     load cycle    

Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for

ZENG Wei, PENG Yongzhen, WANG Shuying

《环境科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 28-32 doi: 10.1007/s11783-007-0005-5

摘要: In order to improve the nitrogen removal efficiency and save operational cost, the feasibility of the alternating aerobic-anoxic process (AAA process) applied in a sequencing batch reactor (SBR) system for nitrogen removal was investigated. Under sufficient influent alkalinity, the AAA process did not have an advantage over one aerobicanoxic (OAA) cycle on treatment efficiency because microorganisms had an adaptive stage at the alternating aerobic-anoxic transition, which would prolong the total cycling time. On the contrary, the AAA process made the system control more complicated. Under deficient influent alkalinity, when compared to OAA, the AAA process improved treatment efficiency and effluent quality with NH-N in the effluent below the detection limit. In the nitrification, the average stoichiometric ratio between alkalinity consumption and ammonia oxidation is calculated to be 7.07 mg CaCO/mg NH-N. In the denitrification, the average stoichiometric ratio between alkalinity production and NO-N reduction is about 3.57 mg CaCO/mg NO-N. As a result, half of the alkalinity previously consumed during the aerobic nitrification was recovered during the subsequent anoxic denitrification period. That was why the higher treatment efficiency in the AAA process was achieved without the supplement of bicarbonate alkalinity. If the lack of alkalinity in the influent was less than 1/3 of that needed, there is no need for external alkalinity addition and treatment efficiency was the same as that under sufficient influent alkalinity. Even if the lack of alkalinity in the influent was more than 1/3 of that needed, the AAA process was an optimal strategy because it reduced the external alkalinity addition and saved on operational cost.

关键词: bicarbonate alkalinity     sufficient influent     influent alkalinity     detection     alkalinity production    

高能激光与应用光学的几个问题

杜祥琬

《中国工程科学》 2001年 第3卷 第2期   页码 21-24

摘要:

高能激光的产生、传输和应用是现代激光技术和光学工程的一个重要发展方向。它不仅涉及到一系列物理问题,还有赖于多项要求极高的工程技术问题。文章提出了8个与高能激光有关的应用光学问题,包括高能激光器、高质量光学元器件、先进的自适应光学技术、非线性光学相共轭技术、变频技术及光束相干合成技术等。着重阐明对它们的要求和可能的发展方向。

关键词: 高能激光     远距传输     应用光学    

标题 作者 时间 类型 操作

Unconventional hydrodynamics of hybrid fluid made of liquid metals and aqueous solution under appliedfields

Xu-Dong ZHANG, Yue SUN, Sen CHEN, Jing LIU

期刊论文

Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

期刊论文

NITROGEN USE AND MANAGEMENT IN ORCHARDS AND VEGETABLE FIELDS IN CHINA: CHALLENGES AND SOLUTIONS

期刊论文

Coordinate system applied to magnetic suspension project between Shanghai and Hangzhou

SHI Yimin, WANG Lihua, LUO Yan

期刊论文

Advanced biomass materials: progress in the applications for energy, environmental, and emerging fields

期刊论文

Engineering Fronts in fields of Energy and Electrical Science and Technologies in the report of

期刊论文

The perturbed magnetic fields caused by mechanical stress

QIN Fei, YAN Dong-mei

期刊论文

Stem cell niches and endogenous electric fields in tissue repair

null

期刊论文

Characterization of random stress fields obtained from polycrystalline aggregate calculations using multi-scale

Bruno SUDRET,Hung Xuan DANG,Marc BERVEILLER,Asmahana ZEGHADI,Thierry YALAMAS

期刊论文

Decomposition analysis applied to energy and emissions: A literature review

期刊论文

Modeling water and heat transfer in soil-plant-atmosphere continuum applied to maize growth under plastic

Meng DUAN, Jin XIE, Xiaomin MAO

期刊论文

Extrapolation reconstruction of wind pressure fields on the claddings of high-rise buildings

Yehua SUN, Guquan SONG, Hui LV

期刊论文

Preliminary design of an SCO conversion system applied to the sodium cooled fast reactor

期刊论文

Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for

ZENG Wei, PENG Yongzhen, WANG Shuying

期刊论文

高能激光与应用光学的几个问题

杜祥琬

期刊论文