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A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

《能源前沿（英文）》 2012年第6卷第1期页码 89-97 doi: 10.1007/s11708-012-0176-z

摘要： This paper discusses two problems in in-line particle sizing when using light fluctuation method. First, by retrieving the ratio of particle concentrations at different time, the intensity of incident light is obtained. There exists narrow error between the calculated and pre-detected value of the intensity of incident light. Secondly, by combining spectrum analysis with Gregory’s theory, a multi-sub-size zone model is proposed, with which the relationship between the distribution of turbidity and the particle size distribution (PSD) can be established, and an algorithm developed to determine the distribution of turbidity. Experiments conducted in the laboratory indicate that the measured size distribution of pulverized coal conforms well with the imaging result.

关键词： in-line measurement particle size distribution (PSD) incident light intensity particle concentration light fluctuation

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Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

Binrong WEN, Sha WEI, Kexiang WEI, Wenxian YANG, Zhike PENG, Fulei CHU

《机械工程前沿（英文）》 2017年第12卷第3期页码 321-332 doi: 10.1007/s11465-017-0434-1

摘要：

The magnitude and stability of power output are two key indices of wind turbines. This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine. First, wind speed models, particularly the wind shear model and the tower shadow model, are described in detail. The widely accepted tower shadow model is modified in view of the cone-shaped towers of modern large-scale wind turbines. Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory. Results indicate that power fluctuation is mainly caused by tower shadow, whereas power loss is primarily induced by wind shear. Under steady wind conditions, power loss can be divided into wind farm loss and rotor loss. Wind farm loss is constant at 3α(3α−1)R²/(8H²). By contrast, rotor loss is strongly influenced by the wind turbine control strategies and wind speed. That is, when the wind speed is measured in a region where a variable-speed controller works, the rotor loss stabilizes around zero, but when the wind speed is measured in a region where the blade pitch controller works, the rotor loss increases as the wind speed intensifies. The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.

关键词： wind turbine wind shear tower shadow power fluctuation power loss

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基于同步波动原理的抗冲蚀弹性涂层设计

郭源君,肖华林,徐大清,李文斌

《中国工程科学》 2008年第10卷第9期页码 60-63

摘要：

基于过流面冲蚀波纹形貌特征与流体边界层扰动波参数的对应关系，提出了实现弹性涂层边壁与边界层扰动波的同步波动，从而变边壁被动承受粒子冲击为主动回避与粒子的碰撞的抗冲蚀设计思想；分析了实现弹性涂层边壁与边界层扰动波同步波动的条件，并由此确定出弹性涂层的材料常数。

关键词：冲蚀边界层弹性边壁弹性涂层同步波动

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Photocatalysis: from solar light to hydrogen energy

《能源前沿（英文）》 2021年第15卷第3期页码 565-567 doi: 10.1007/s11708-021-0784-6

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Optimal portfolio design of energy storage devices with financial and physical right market

《能源前沿（英文）》 2022年第16卷第1期页码 95-104 doi: 10.1007/s11708-021-0788-2

摘要： With the continuous development of the spot market, in the multi-stage power market environment with the day-ahead market and right market, the study associated with the portfolio of energy storage devices requires that attention should be paid to transmission congestion and power congestion. To maximize the profit of energy storage and avoid the imbalance of power supply and consumption and the risk of node price fluctuation caused by transmission congestion, this paper presents a portfolio strategy of energy storage devices with financial/physical contracts. First, the concepts of financial/physical transmission rights and financial/physical storage rights are proposed. Then, the portfolio models of financial contract and physical contract are established with the conditional value-at-risk to measure the risks. Finally, the portfolio models are verified through the test data of the Pennsylvania-New Jersey-Maryland (PJM) electric power spot market, and the comparison between the risk aversion of portfolios based on financial/physical contract with the portfolio of the market without rights. The simulation results show that the portfolio models proposed in this paper can effectively avoid the risk of market price fluctuations.

关键词： portfolio node price fluctuation transmission right energy storage right risk aversion

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HQ in inland saline-alkaline water under different light qualities

《环境科学与工程前沿（英文）》 2022年第16卷第4期 doi: 10.1007/s11783-021-1479-2

摘要：

• Optimal growth of Chlorella in inland saline-alkaline water was achieved by blue LED.

关键词： Light quality Chlorella Inland saline-alkaline water Fatty acid Biodiesel property

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Effect of light scattering on the performance of a direct absorption solar collector

Kwang Hyun WON, Bong Jae LEE

《能源前沿（英文）》 2018年第12卷第1期页码 169-177 doi: 10.1007/s11708-018-0527-5

摘要： Recently, a solar thermal collector often employs nanoparticle suspension to absorb the solar radiation directly by a working fluid as well as to enhance its thermal performance. The collector efficiency of a direct absorption solar collector (DASC) is very sensitive to optical properties of the working fluid, such as absorption and scattering coefficients. Most of the existing studies have neglected particle scattering by assuming that the size of nanoparticle suspension is much smaller than the wavelength of solar radiation (i.e., Rayleigh scattering is applicable). If the nanoparticle suspension is made of metal, however, the scattering cross-section of metallic nanoparticles could be comparable to their absorption cross-section depending on the particle size, especially when the localized surface plasmon (LSP) is excited. Therefore, for the DASC utilizing a plasmonic nanofluid supporting the LSP, light scattering from metallic particle suspension must be taken into account in the thermal analysis. The present study investigates the scattering effect on the thermal performance of the DASC employing plasmonic nanofluid as a working fluid. In the analysis, the Monte Carlo method is employed to numerically solve the radiative transfer equation considering the volume scattering inside the nanofluid. It is found that the light scattering can improve the collector performance if the scattering coefficient of nanofluid is carefully engineered depending on its value of the absorption coefficient.

关键词： direct absorption solar collector plasmonic nanofluid light scattering

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Plasmonic light trapping for enhanced light absorption in film-coupled ultrathin metamaterial thermophotovoltaic

Qing NI, Hassan ALSHEHRI, Yue YANG, Hong YE, Liping WANG

《能源前沿（英文）》 2018年第12卷第1期页码 185-194 doi: 10.1007/s11708-018-0522-x

摘要： Ultrathin cells have gained increasing attention due to their potential for reduced weight, reduced cost and increased flexibility. However, the light absorption in ultrathin cells is usually very weak compared to the corresponding bulk cells. To achieve enhanced photon absorption in ultrathin thermophotovoltaic (TPV) cells, this work proposed a film-coupled metamaterial structure made of nanometer-thick gallium antimonide (GaSb) layer sandwiched by a top one-dimensional (1D) metallic grating and a bottom metal film. The spectral normal absorptance of the proposed structure was calculated using the rigorous coupled-wave algorithm (RCWA) and the absorption enhancement was elucidated to be attributed to the excitations of magnetic polariton (MP), surface plasmon polariton (SPP), and Fabry-Perot (FP) resonance. The mechanisms of MP, SPP, and FP were further confirmed by an inductor-capacitor circuit model, dispersion relation, and phase shift, respectively. Effects of grating period, width, spacer thickness, as well as incidence angle were discussed. Moreover, short-circuit current density, open-circuit voltage, output electric power, and conversion efficiency were evaluated for the ultrathin GaSb TPV cell with a film-coupled metamaterial structure. This work will facilitate the development of next-generation low-cost ultrathin infrared TPV cells.

关键词： metamaterial thermophotovoltaic plasmonics light trapping selective absorption

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Lignin-derived dual-function red light carbon dots for hypochlorite detection and anti-counterfeiting

《化学科学与工程前沿（英文）》 doi: 10.1007/s11705-022-2244-1

摘要： The efficient utilization of natural lignin, which is the main by-product of the cellulose industry, is crucial for enhancing its economic value, alleviating the environmental burden, and improving ecological security. By taking advantage of the large sp² hybrid domain of lignin and introducing amino functional groups, new lignin-derived carbon dots (SPN-CDs) with red fluorescence were successfully synthesized. Compared with green and blue fluorescent materials, red SPN-CDs have desirable anti-interference properties of short-wave background and exhibit superior luminescence stability. The SPN-CDs obtained exhibited sensitive and distinctive visible color with fluorescence-dual responses toward hypochlorite. Considering this feature, a portable, low-cost, and sensitive fluorescence sensing paper with a low limit of detection of 0.249 μmol∙L^–1 was fabricated using the SPN-CDs for hypochlorite detection. Furthermore, a new type of visible-light and fluorescence dual-channel information encryption platform was constructed. Low-concentration hypochlorite can be employed as an accessible and efficient information encryption/decryption stimulus, as well as an information “eraser”, facilitating a safe and diversified transmission and convenient decryption of information. This work opens new avenues for high-value-added applications of lignin-based fluorescent materials.

关键词： alkali lignin red light carbon dots hypochlorite encryption and anti-counterfeiting

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Light olefins synthesis from С

Anton SHALYGIN, Evgenii PAUKSHTIS, Evgenii KOVALYOV, Bair BAL’ZHINIMAEV

《化学科学与工程前沿（英文）》 2013年第7卷第3期页码 279-288 doi: 10.1007/s11705-013-1338-1

摘要： A two-step process was employed to convert methane or ethane to light olefins via the formation of an intermediate monoalkyl halide. A novel K RuOCl /TiO catalyst was tested for the oxidative chlorination of methane and ethane. The catalyst had high selectivity for methyl and ethyl chlorides, 80% and 90%, respectively. During the oxychlorination of ethane at ≥250°C, the formation of ethylene as a reaction product along with ethyl chloride was observed. In situ Fourier transform infrared studies showed that the key intermediate for monoalkyl chloride and ethylene formation is the alkoxy group. The reaction mechanism for the oxidative chlorination of methane and ethane over the Ru-oxychloride catalyst was proposed. The novel fiber glass catalyst was also tested for the dehydrochlorination of alkyl chlorides to ethylene and propylene. Very high selectivities (up to 94%–98%) for ethylene and propylene formation as well as high stability were demonstrated.

关键词： oxychlorination methane ethane light olefins ruthenium catalyst

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Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

《结构与土木工程前沿（英文）》 2017年第11卷第4期页码 412-423 doi: 10.1007/s11709-017-0416-8

摘要： Construction loading before the age of 28 d can have the most significant effects on the slabs, especially for multi-story structures. The changing properties of the young concrete complicate the prediction of serviceability design requirements also. An experimental investigation is performed on four simply supported Light-Weight Concrete (LWC) one-way slabs subjected to immediate loading at 14 d. Effects of aggregate type, loading levels and cracking moment together with the influences of ultimate moment capacity and service moment on the instantaneous deflection of slabs are studied. Comparison of the obtained results with predictions of existing models in the literature shows considerable differences between the recorded and estimated instantaneous deflection of LWC slabs. Based on sensitivity analysis of the effective parameters, a new equation is proposed and verified to predict the instantaneous deflection of LWC slabs subjected to loading at the age of 14 d.

关键词： instantaneous deflection light-weight concrete expanded polystyrene effective moment of inertia cracking moment moment capacity service moment

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Nanostructured gold films exhibiting almost complete absorption of light at visible wavelengths

Hanbin Zheng, Christine Picard, Serge Ravaine

《化学科学与工程前沿（英文）》 2018年第12卷第2期页码 247-251 doi: 10.1007/s11705-018-1710-2

摘要： Nanostructured metal surfaces have been known to exhibit properties that deviate from that of the bulk material. By simply modifying the texture of a metal surface, various unique optical properties can be observed. In this paper, we present a simple two step electrochemical process combining electrodeposition and anodization to generate black gold surfaces. This process is simple, versatile and up-scalable for the production of large surfaces. The black gold films have remarkable optical behavior as they absorb more than 93% of incident light over the entire visible spectrum and also exhibit no specular reflectance. A careful analysis by scanning electron microscopy reveals that these unique optical properties are due to their randomly rough surface, as they consist in a forest of dendritic microstructures with a nanoscale roughness. This new type of black films can be fabricated to a large variety of substrates, turning them to super absorbers with potential applications in photovoltaic solar cells or highly sensitive detectors and so on.

关键词： nanostructuration light absorption coating gold electrodeposition anodization

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Visible light responsive photocatalysts developed by substitution with metal cations aiming at artificial

《能源前沿（英文）》 2021年第15卷第3期页码 568-576 doi: 10.1007/s11708-021-0774-8

摘要： To solve resource, energy, and environmental issues, development of sustainable clean energy system is strongly required. In recent years, hydrogen has been paid much attention to as a clean energy. Solar hydrogen production by water splitting using a photocatalyst as artificial photosynthesis is a promising method to solve these issues. Efficient utilization of visible light comprised of solar light is essential for practical use. Three strategies, i.e., doping, control of valence band, and formation of solid solution are often utilized as the useful methods to develop visible light responsive photocatalysts. This mini-review introduces the recent work on visible-light-driven photocatalysts developed by substitution with metal cations of those strategies.

关键词： visible light responsive photocatalyst water splitting artificial photosynthesis: metal ion substitution

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LIGHT INTERCEPTION AND USE EFFICIENCY DIFFER WITH MAIZE PLANT DENSITY IN MAIZE-PEANUT INTERCROPPING

《农业科学与工程前沿（英文）》 2021年第8卷第3期页码 432-446 doi: 10.15302/J-FASE-2021403

摘要：

Intercropping increases crop yields by optimizing light interception and/or use efficiency. Although intercropping combinations and metrics have been reported, the effects of plant density on light use are not well documented. Here, we examined the light interception and use efficiency in maize-peanut intercropping with different maize plant densities in two row configurations in semiarid dryland agriculture over a two-year period. The field experiment comprised four cropping systems, i.e. monocropped maize, monocropped peanut, maize-peanut intercropping with two rows of maize and four rows of peanut, intercropping with four rows of maize and four rows of peanut, and three maize plant densities (3.0, 4.5 and 6.0 plants m⁻¹ row) in both monocropped and intercropping maize. The mean total light interception in intercropping across years and densities was 779 MJ·m⁻², 5.5% higher than in monocropped peanut (737 MJ·m⁻²) and 7.6% lower than in monocropped maize (843 MJ·m⁻²). Increasing maize density increased light interception in monocropped maize but did not affect the total light interception in the intercrops. Across years the LUE of maize was 2.9 g·MJ⁻¹ and was not affected by cropping system but increased with maize plant density. The LUE of peanut was enhanced in intercropping, especially in a wetter year. The yield advantage of maize-peanut intercropping resulted mainly from the LUE of peanut. These results will help to optimize agronomic management and system design and provide evidence for system level light use efficiency in intercropping.

关键词： dryland agriculture light interception light use efficiency maize-peanut intercropping semiarid