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增材制造 5

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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    

选区激光熔化纯钨——粉末粒径对激光吸收的影响和扫描轨迹形成机理研究 Article

章佳窈, 顾冬冬, 杨莹, 张红梅, 陈洪宇, 戴冬华, 林开杰

《工程(英文)》 2019年 第5卷 第4期   页码 736-745 doi: 10.1016/j.eng.2019.07.003

摘要:

本文建立了基于线迹追踪的三维激光吸收模型,用于描述选区激光熔化(SLM)成形纯钨粉末时激光束与粉末层的相互作用,研究了粉末粒径大小对粉末激光吸收率和吸收行为的影响。本文给出了激光吸收率、粉层吸收辐照度及其分布、激光扫描轨迹的表面形貌和几何特征(如接触角、宽度和高度,以及重熔深度)之间的内在关系。模拟结果表明,粉末层的吸收率大大超过单一的粉末颗粒或致密平板材料的吸收率。随着粉末粒径增加,粉末层吸收的激光能量减少。当粒径为5 μm时,纯钨粉末层的吸收率最大达到0.6030。激光辐照度在粉床颗粒表面的分布与粒径大小、方位角和粉末在基板上的位置有关。当粒径从5 μm增加到45 μm时,粉末层中的最大辐照度从1.117 × 10–3 W·μm–2降低到0.85 × 10–3 W·μm–2,并且位于中心辐照区域的辐照度分布轮廓逐渐收缩。对SLM纯钨扫描轨迹的表面形貌和横截面几何特征进行了研究,结果验证了模拟的粉末激光吸收行为。该工作对线迹追踪模型预测SLM扫描轨迹润湿性和铺展性的应用提供了科学依据,从而更好地获得优异的激光成形性能。

关键词: 选区激光熔化         线迹追踪模型     吸收率     激光扫描轨迹    

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    

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    

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

《能源前沿(英文)》 2019年 第13卷 第1期   页码 185-192 doi: 10.1007/s11708-017-0452-z

摘要: Solar absorption-subcooled compression hybrid refrigeration system is a new type of efficient and economical solar refrigeration device which always meets the demand of cooling load with the change of solar irradiance. The performance of the hybrid system is higher due to the improvement of evaporator temperature of absorption subsystem. But simultaneously, the variation of working process as well as performance is complicated since the absorption and compression subsystems are coupled strongly. Based on the measured meteorological data of Guangzhou, a subtropical city in south China, a corresponding parametric model has been developed for the hybrid refrigeration system, and a program written by Fortran has been used to analyze the performance of the hybrid system under different external conditions. As the condensation temperature ranges from 38°C to 50°C, the working time fraction of the absorption subsystem increases from 75% to 85%. Besides, the energy saving fraction also increases from 5.31% to 6.02%. The average COP of the absorption subsystem is improved from 0.366 to 0.407. However, when the temperature of the absorption increases from 36°C to 48°C, the average COP of hybrid system decreases from 2.703 to 2.312. Moreover, the working time fraction of the absorption subsystem decreases from 80% to 71.7%. The energy saving fraction falls from 5.67% to 5.08%. In addition, when the evaporate temperature increases from 4°C to 14°C, the average COP of the absorption subsystem decreases from 0.384 to 0.365. The work of the compressor decreases from 48.2 kW to 32.8 kW and the corresponding average COP of the absorption subsystem is improved from 2.591 to 3.082.

关键词: solar     absorption-subcooled     compression hybrid     dynamic simulation     performance analysis    

Effect of fine solid particles on absorption rate of gaseous CO

LU Sumin, MA Youguang, SHEN Shuhua, ZHU Chunying

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 368-372 doi: 10.1007/s11705-008-0067-3

摘要: The influence of the properties of solid particles in slurry on the absorption of CO in the slurry was investigated in a stirred thermostatic reactor. The absorption experiments were carried out in three different slurries consisting of water, cyclohexane and soybean oil, respectively, and three kinds of solid particles (active carbon, active alumina and silica gel) were incorporated into each of the above mentioned slurries separately. The experimental results show that the active carbon particles could enhance the absorption rate of gaseous CO in the aqueous slurry, while in the cyclohexane slurry, active carbon particles indicated no the absorption enhancement effect. However, it was observed that the active alumina and silica gel particles could enhance the absorption rate of CO in the cyclohexane slurry. These phenomena indicate that the solid particles, which could enhance the gaseous CO absorption rate, should possess two properties simultaneously, i.e. they rejected the solvent and had higher adsorption capacity for the solute. The experimental results also show that, as for those solid particles which could enhance the gas absorption rate, the enhancement increased quickly with the increase of solid concentration in slurry at first, and then reached a constant value gradually. It was also found that the enhancement factor was related to the coverage fraction of solid particles on the gas-liquid interface, and due to the reduction of surface fraction with increasing stirred speed, the enhancement factor decreased.

关键词: constant     influence     soybean     solvent     concentration    

Improving retrieval precision of NO

Jinpeng YANG

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 92-96 doi: 10.1007/s11465-009-0001-5

摘要: The NO density error retrieved by the traditional method of differential optical absorption spectroscopy (DOAS) was analyzed. The technique for reducing the error is proposed and used to obtain the NO density of Chengdu through DOAS.

关键词: absorption structure     low-frequency structure     absorption cross-section     NO2 density    

optimization of 1,3-dimethylimidazolylium dimethylphosphate-water binary mixture for a single effect absorption

Gorakshnath TAKALKAR, Ahmad K. SLEITI

《能源前沿(英文)》 2022年 第16卷 第3期   页码 521-535 doi: 10.1007/s11708-021-0720-9

摘要: The energy and exergy analyses of the absorption refrigeration system (ARS) using H O-[mmim][DMP] mixture were investigated for a wide range of temperature. The equilibrium Dühring ( - - ) and enthalpy ( - - ) of mixture were assessed using the excess Gibbs free non-random two liquid (NRTL) model for a temperature range of 20°C to 140°C and from 0.1 to 0.9. The performance validation of the ARS cycle showed a better coefficient of performance (COP) of 0.834 for H O-[mmim][DMP] in comparison to NH -H O, H O-LiBr, H O-[emim][DMP], and H O-[emim][BF4]. Further, ARS performances with various operating temperatures of the absorber ( ), condenser ( ), generator ( ), and evaporator ( ) were simulated and optimized for a maximum COP and exergetic COP (ECOP). The effects of from 50°C to 150°C and and from 30°C to 50°C on COP and ECOP, the , , and circulation ratio (CR) of the ARS were evaluated and optimized for from 5°C to 15°C. The optimization revealed that needed to achieve a maximum COP which was more than that for a maximum ECOP. Therefore, this investigation provides criteria to select low grade heat source temperature. Most of the series flow of the cases of cooling water from the condenser to the absorber was found to be better than the absorber to the condenser.

关键词: ionic liquid driven absorption cycle     H2O-[mmim][DMP]     coefficient of performance (COP)     exergy analysis     thermodynamics mixture property    

A district heating system based on absorption heat exchange with CHP systems

Lin FU, Yan LI, Yi JIANG, Shigang ZHANG,

《能源前沿(英文)》 2010年 第4卷 第1期   页码 77-83 doi: 10.1007/s11708-010-0022-0

摘要: In order to decrease the energy consumption of large-scale district heating systems with cogeneration, a district heating system is presented in this paper based on absorption heat exchange in the cogeneration system named Co-ah cycle, which means that the cogeneration system is based on absorption heat exchange. In substations of the heating system, the temperature of return water of primary heat network is reduced to about 25°C through the absorption heat-exchange units. In the thermal station of the cogeneration plant, return water is heated orderly by the exhaust steam in the condenser, the absorption heat pumps, and the peak load heater. Compared with traditional heating systems, this system runs with a greater circuit temperature drop so that the delivery capacity of the heat network increases dramatically. Moreover, by recovering the exhausted heat from the condensers, the capacity of the district heating system and the energy efficiency of the combined heat and power system (CHP system) are highly developed. Therefore, high energy and economic efficiency can be obtained.

关键词: cogeneration     district heating     absorption heat exchange     Co-ah cycle    

Improved rate-based modeling of carbon dioxide absorption with aqueous monoethanolamine solution

Stefania MOIOLI, Laura A. PELLEGRINI, Simone GAMBA, Ben LI

《化学科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 123-131 doi: 10.1007/s11705-014-1415-0

摘要: This paper focuses on modeling and simulation of a post-combustion carbon dioxide capture in a coal-fired power plant by chemical absorption using monoethanolamine. The aim is to obtain a reliable tool for process simulation: a customized rate-based model has been developed and implemented in the ASPEN Plus software, along with regressed parameters for the Electrolyte-NRTL model worked out in a previous research. The model is validated by comparison with experimental data of a pilot plant and can provide simulation results very close to experimental data.

关键词: Absorption     carbon dioxide capture     rate-based model     monoethanolamine scrubbing    

Design of efficient Pt-based electrocatalysts through characterization by X-ray absorption spectroscopy

Nebojsa S. MARINKOVIC, Kotaro SASAKI, Radoslav R. ADZIC

《能源前沿(英文)》 2017年 第11卷 第3期   页码 236-244 doi: 10.1007/s11708-017-0487-1

摘要: A method is described to determine the internal structure of electrocatalyst nanoparticles by X-ray absorption spectroscopy (XAS). The nondestructive spectroscopic technique typically utilizing synchrotron radiation as the source measures changes in the X-ray absorption coefficient as a function of energy. The bulk technique has found its use for materials characterization in all scientific areas, including nanomaterials. The analysis of the internal structure of nanoparticles reveals interatomic distances and coordination numbers for each element, and their values and mutual relations indicate whether the elements form a homogeneous or heterogeneous mixture. The core-shell heterogeneous structure in which certain elements are predominantly located in the core, and others form the encapsulating shell is of particular importance in catalysis and electrocatalysis because it may reduce the amount of precious metals in nanoparticles by replacing the atoms in the core of nanoparticles with more abundant and cheaper alternatives. The examples of nanoparticle structures designed in the laboratory and the approach to model efficient catalysts through systematic analysis of XAS data in electrochemical systems consisting of two and three metals are also demonstrated.

关键词: X-ray absorption spectroscopy     EXAFS     XANES     nanocatalysts     core shell    

Recent advances in selective acetylene hydrogenation using palladium containing catalysts

Alan J. McCue, James A. Anderson

《化学科学与工程前沿(英文)》 2015年 第9卷 第2期   页码 142-153 doi: 10.1007/s11705-015-1516-4

摘要: Recent advances with Pd containing catalysts for the selective hydrogenation of acetylene are described. The overview classifies enhancement of catalytic properties for monometallic and bimetallic Pd catalysts. Activity/selectivity of Pd catalysts can be modified by controlling particle shape/morphology or immobilisation on a support which interacts strongly with Pd particles. In both cases enhanced ethylene selectivity is generally associated with modifying ethylene adsorption strength and/or changes to hydride formation. Inorganic and organic selectivity modifiers (i.e., species adsorbed onto Pd particle surface) have also been shown to enhance ethylene selectivity. Inorganic modifiers such as TiO change Pd ensemble size and modify ethylene adsorption strength whereas organic modifiers such as diphenylsulfide are thought to create a surface template effect which favours acetylene adsorption with respect to ethylene. A number of metals and synthetic approaches have been explored to prepare Pd bimetallic catalysts. Examples where enhanced selectivity is observed are generally associated with decreased Pd ensemble size and/or hindering of the ease with which an unselective hydride phase is formed for Pd. A final class of bimetallic catalysts are discussed where Pd is not thought to be the primary reaction site but merely acts as a site where hydrogen dissociation and spillover occurs onto a second metal (Cu or Au) where the reaction takes place more selectively.

关键词: acetylene     ethylene     selective hydrogenation     palladium     bimetallic    

Preparation of polysulfone-based block copolymer ultrafiltration membranes by selective swelling and

《化学科学与工程前沿(英文)》 2022年 第16卷 第5期   页码 745-754 doi: 10.1007/s11705-021-2038-x

摘要: Selective swelling of block copolymers of polysulfone-b-poly(ethylene glycol) is an emerging strategy to prepare new types of polysulfone ultrafiltration membranes. Herein, we prepared nanoporous polysulfone-b-poly(ethylene glycol) ultrafiltration membranes by selective swelling and further promoted their porosity and ultrafiltration performances by using CaCO3 nanoparticles as the sacrificial nanofillers. Different contents of CaCO3 nanoparticles were doped into the solution of polysulfone-b-poly(ethylene glycol), and thus obtained suspensions were used to prepare both self-supported and bi-layered composite structures. Selective swelling was performed on the obtained block copolymer structures in the solvent pair of ethanol/acetone, producing nanoporous membranes with poly(ethylene glycol) lined along pore walls. The CaCO3 nanoparticles dispersed in polysulfone-b-poly(ethylene glycol) were subsequently etched away by hydrochloric acid and the spaces initially occupied by CaCO3 provided extra pores to the block copolymer layers. The porosity of the membranes was increased with increasing CaCO3 content up to 41%, but further increase in the CaCO3 content led to partial collapse of the membrane. The sacrificial CaCO3 particles provided extra pores and enhanced the connectivity between adjacent pores. Consequently, the membranes prepared under optimized conditions exhibited up to 80% increase in water permeance with slight decrease in rejection compared to neat membranes without the use of sacrificial CaCO3 particles.

关键词: block copolymers     selective swelling     ultrafiltration     CaCO3 nanoparticles     sacrificial nanofillers    

Effect of fiber hybridization on energy absorption and synergy in concrete

Ahmadreza RAMEZANI, Mohammad Reza ESFAHANI

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1338-1349 doi: 10.1007/s17009-019-0558-2

摘要: In the present study, steel and polypropylene (PP) fibers have been utilized with the intent of obtaining hybrid fiber-reinforced concrete (HFRC) with desirable mechanical properties. An attempt has been made to scrutinize the properties of HFRC with the main concentration being on energy absorption characteristics of concrete and the efficacy of fiber hybridization in producing synergy. Accordingly, a total of 180 specimens, representing 20 different mixtures have been cast and evaluated through compressive, split tensile, and flexural tests. The relevant flexural toughness of the specimens was calculated using ASTM C1018, ASTM C1609, JSCE, and PCS methods, and the effectiveness of these methods was evaluated based on the experimental results. It was observed that steel fibers are more effective in the improvement of flexural toughness in the presence of PP fibers. Furthermore, synergy associated with the combination of fibers at different stages of deflection of the beam specimens was observed and analyzed.

关键词: hybrid fiber-reinforced concrete     synergy     toughness     steel fibers     polypropylene fibers    

Numerical study of a hybrid absorption-compression high temperature heat pump for industrial waste heat

Zhiwei MA, Huashan BAO, Anthony Paul ROSKILLY

《能源前沿(英文)》 2017年 第11卷 第4期   页码 503-509 doi: 10.1007/s11708-017-0515-1

摘要: The present paper aims at exploring a hybrid absorption-compression heat pump (HAC-HP) to upgrade and recover the industrial waste heat in the temperature range of 60°C–120°C. The new HAC-HP system proposed has a condenser, an evaporator, and one more solution pump, compared to the conventional HAC-HP system, to allow flexible utilization of energy sources of electricity and waste heat. In the system proposed, the pressure of ammonia-water vapor desorbed in the generator can be elevated by two routes; one is via the compression of compressor while the other is via the condenser, the solution pump, and the evaporator. The results show that more ammonia-water vapor flowing through the compressor leads to a substantial higher energy efficiency due to the higher quality of electricity, however, only a slight change on the system exergy efficiency is noticed. The temperature lift increases with the increasing system recirculation flow ratio, however, the system energy and exergy efficiencies drop towards zero. The suitable operation ranges of HAC-HP are recommended for the waste heat at 60°C, 80°C, 100°C, and 120°C. The recirculation flow ratio should be lower than 9, 6, 5, and 4 respectively for these waste heat, while the temperature lifts are in the range of 9.8°C–27.7 °C, 14.9°C–44.1 °C, 24.4°C–64.1°C, and 40.7°C–85.7°C, respectively, and the system energy efficiency are 0.35–0.93, 0.32–0.90, 0.25–0.85, and 0.14–0.76.

关键词: absorption compression     high temperature heat pump     efficiency     industrial waste heat     thermodynamic analysis    

标题 作者 时间 类型 操作

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

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

期刊论文

选区激光熔化纯钨——粉末粒径对激光吸收的影响和扫描轨迹形成机理研究

章佳窈, 顾冬冬, 杨莹, 张红梅, 陈洪宇, 戴冬华, 林开杰

期刊论文

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

Hanbin Zheng, Christine Picard, Serge Ravaine

期刊论文

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

Kwang Hyun WON, Bong Jae LEE

期刊论文

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

期刊论文

Effect of fine solid particles on absorption rate of gaseous CO

LU Sumin, MA Youguang, SHEN Shuhua, ZHU Chunying

期刊论文

Improving retrieval precision of NO

Jinpeng YANG

期刊论文

optimization of 1,3-dimethylimidazolylium dimethylphosphate-water binary mixture for a single effect absorption

Gorakshnath TAKALKAR, Ahmad K. SLEITI

期刊论文

A district heating system based on absorption heat exchange with CHP systems

Lin FU, Yan LI, Yi JIANG, Shigang ZHANG,

期刊论文

Improved rate-based modeling of carbon dioxide absorption with aqueous monoethanolamine solution

Stefania MOIOLI, Laura A. PELLEGRINI, Simone GAMBA, Ben LI

期刊论文

Design of efficient Pt-based electrocatalysts through characterization by X-ray absorption spectroscopy

Nebojsa S. MARINKOVIC, Kotaro SASAKI, Radoslav R. ADZIC

期刊论文

Recent advances in selective acetylene hydrogenation using palladium containing catalysts

Alan J. McCue, James A. Anderson

期刊论文

Preparation of polysulfone-based block copolymer ultrafiltration membranes by selective swelling and

期刊论文

Effect of fiber hybridization on energy absorption and synergy in concrete

Ahmadreza RAMEZANI, Mohammad Reza ESFAHANI

期刊论文

Numerical study of a hybrid absorption-compression high temperature heat pump for industrial waste heat

Zhiwei MA, Huashan BAO, Anthony Paul ROSKILLY

期刊论文