资源类型

期刊论文 63

年份

2024 1

2023 11

2022 9

2020 4

2019 2

2018 1

2017 9

2016 3

2015 3

2014 2

2012 3

2011 3

2010 1

2009 1

2008 3

2007 2

2005 1

2004 1

2001 1

2000 1

展开 ︾

关键词

功率谱密度 2

CCD影像 1

Chrestenson谱 1

MIMO雷达；波形设计；谱分解；分式二次约束二次规划 1

PIC16F877A 1

RS—485总线 1

dsPIC30F4012 1

m值逻辑函数 1

“上限” 1

三维 1

严格雪崩准则 1

亚铁氰化铜 1

光纤通信 1

光谱信息 1

光谱成像；计算成像；光谱仪 1

分子荧光光谱 1

分析滤波器；线性预测；窄带语音水印；通带激励替代；能量规范化；谱包络成形；合成滤波器 1

单价选择性阳离子交换膜 1

反射光谱 1

展开 ︾

检索范围：

排序： 展示方式：

A spectrally selective surface structure for combined photothermic conversion and radiative sky cooling

Bin ZHAO, Xianze AO, Nuo CHEN, Qingdong XUAN, Mingke HU, Gang PEI

《能源前沿（英文）》 2020年 第14卷 第4期   页码 882-888 doi: 10.1007/s11708-020-0694-z

摘要： The sun and outer space are the ultimate heat and cold sources for the earth, respectively. They have significant potential for renewable energy harvesting. In this paper, a spectrally selective surface structure that has a planar polydimethylsiloxane layer covering a solar absorber is conceptually proposed and optically designed for the combination of photothermic conversion (PT) and nighttime radiative sky cooling (RC). An optical simulation is conducted whose result shows that the designed surface structure (i.e., PT-RC surface structure) has a strong solar absorption coefficient of 0.92 and simultaneously emits as a mid-infrared spectral-selective emitter with an average emissivity of 0.84 within the atmospheric window. A thermal analysis prediction reveals that the designed PT-RC surface structure can be heated to 79.1°C higher than the ambient temperature in the daytime and passively cooled below the ambient temperature of approximately 10°C in the nighttime, indicating that the designed PT-RC surface structure has the potential for integrated PT conversion and nighttime RC utilization.

关键词： solar energy     photothermic conversion     radiative sky cooling     spectral selectivity     multilayer film    

HTML PDF 收藏

Tuning the catalytic selectivity in electrochemical CO

Jiafang XIE,Yuxi HUANG,Hanqing YU

《环境科学与工程前沿（英文）》 2015年 第9卷 第5期   页码 861-866 doi: 10.1007/s11783-014-0742-1

摘要： Electrochemical conversion of CO to hydrocarbons can relieve both environmental and energy stresses. However, electrocatalysts for this reaction usually suffer from a poor product selectivity and a large overpotential. Here we report that tunable catalytic selectivity for hydrocarbon formation could be achieved on Cu nanomaterials with different morphologies. By tuning the electrochemical parameters, either Cu oxide nanowires or nanoneedles were fabricated and then electrochemically reduced to the corresponding Cu nanomaterials. The Cu nanowires preferred the formation of C H , while the Cu nanoneedles favored the production of more CH , rather than C H . Our work provides a facile synthetic strategy for preparing Cu-based nanomaterials to achieve selective CO reduction.

关键词： electrochemical CO2 reduction     Cu oxide     nanostructure     selectivity     hydrocarbon formation    

HTML PDF 收藏

An investigation of the CHOH and CO selectivity of CO hydrogenation over Cu–Ce–Zr catalysts

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 950-962 doi: 10.1007/s11705-022-2162-2

摘要： A series of Cu–Ce–Zr catalysts with different Ce contents are applied to the hydrogenation of CO2 to CO/CH3OH products. The Cu–Ce–Zr catalyst with 2 wt% Ce loading shows higher CO selectivity (SCO = 0.0%–87.8%) from 200–300 °C, while the Cu–Ce–Zr catalyst with 8 wt% Ce loading presents higher CO2 conversion ( XCO2 = 5.4%–15.6%) and CH3OH selectivity ( SCH3OH = 97.8%–40.6%). The number of hydroxyl groups and solid solution nature play a significant role in changing the reaction pathway. The solid solution enhances the CO2 adsorption ability. At the CO2 adsorption step, a larger number of hydroxyl groups over the Cu–Ce–Zr catalyst with 8 wt% Ce loading leads to the production of H-containing adsorption species. At the CO2 hydrogenation step, a larger number of hydroxyl groups assists in encouraging the further hydrogenation of intermediate species to CH3OH and improving the hydrogenation rate. Hence, the Cu–Ce–Zr catalyst with 8 wt% Ce loading favors CH3OH selectivity and CO2 activation, while CO is preferred on the Cu–Ce–Zr catalyst with 2 wt% Ce loading, a smaller number of hydroxyl groups and a solid solution nature. Additionally, high-pressure in situ diffuse reflectance infrared Fourier transform spectroscopy shows that CO is produced from formate decomposition and that both monodentate formate and bidentate formate are active intermediate species of CO2 hydrogenation to CH3OH.

关键词： CO2 hydrogenation     Cu–Ce–Zr     hydroxyls     CO/CH3OH selectivity    

HTML PDF 收藏

Applying the spectral stochastic finite element method in multiple-random field RC structures

Abbas YAZDANI

《结构与土木工程前沿（英文）》 2022年 第16卷 第4期   页码 434-447 doi: 10.1007/s11709-022-0820-6

摘要： This paper uses the spectral stochastic finite element method (SSFEM) for analyzing reinforced concrete (RC) beam/slab problems. In doing so, it presents a new framework to study how the correlation length of a random field (RF) with uncertain parameters will affect modeling uncertainties and reliability evaluations. It considers: 1) different correlation lengths for uncertainty parameters, and 2) dead and live loads as well as the elasticity moduli of concrete and steel as a multi-dimensional RF in concrete structures. To show the SSFEM’s efficiency in the study of concrete structures and to evaluate the sensitivity of the correlation length effects in evaluating the reliability, two examples of RC beams and slabs have been investigated. According to the results, the RF correlation length is effective in modeling uncertainties and evaluating reliabilities; the longer the correlation length, the greater the dispersion range of the structure response and the higher the failure probability.

关键词： uncertainty     spectral stochastic finite element method     correlation length     reliability assessment     reinforced concrete beam/slab    

HTML PDF 收藏

Fault feature extraction of planet gear in wind turbine gearbox based on spectral kurtosis and time wavelet

Yun KONG, Tianyang WANG, Zheng LI, Fulei CHU

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 406-419 doi: 10.1007/s11465-017-0419-0

摘要：

Planetary transmission plays a vital role in wind turbine drivetrains, and its fault diagnosis has been an important and challenging issue. Owing to the complicated and coupled vibration source, time-variant vibration transfer path, and heavy background noise masking effect, the vibration signal of planet gear in wind turbine gearboxes exhibits several unique characteristics: Complex frequency components, low signal-to-noise ratio, and weak fault feature. In this sense, the periodic impulsive components induced by a localized defect are hard to extract, and the fault detection of planet gear in wind turbines remains to be a challenging research work. Aiming to extract the fault feature of planet gear effectively, we propose a novel feature extraction method based on spectral kurtosis and time wavelet energy spectrum (SK-TWES) in the paper. Firstly, the spectral kurtosis (SK) and kurtogram of raw vibration signals are computed and exploited to select the optimal filtering parameter for the subsequent band-pass filtering. Then, the band-pass filtering is applied to extrude periodic transient impulses using the optimal frequency band in which the corresponding SK value is maximal. Finally, the time wavelet energy spectrum analysis is performed on the filtered signal, selecting Morlet wavelet as the mother wavelet which possesses a high similarity to the impulsive components. The experimental signals collected from the wind turbine gearbox test rig demonstrate that the proposed method is effective at the feature extraction and fault diagnosis for the planet gear with a localized defect.

关键词： wind turbine     planet gear fault     feature extraction     spectral kurtosis     time wavelet energy spectrum    

HTML PDF 收藏

Solar fuel from photo-thermal catalytic reactions with spectrum-selectivity: a review

Sanli TANG, Jie SUN, Hui HONG, Qibin LIU

《能源前沿（英文）》 2017年 第11卷 第4期   页码 437-451 doi: 10.1007/s11708-017-0509-z

摘要： Solar fuel is one of the ideal energy sources in the future. The synergy of photo and thermal effects leads to a new approach to higher solar fuel production under relatively mild conditions. This paper reviews different approaches for solar fuel production from spectrum-selective photo-thermal synergetic catalysis. The review begins with the meaning of synergetic effects, and the mechanisms of spectrum-selectivity and photo-thermal catalysis. Then, from a technical perspective, a number of experimental or theoretical works are sorted by the chemical reactions and the sacrificial reagents applied. In addition, these works are summarized and tabulated based on the operating conditions, spectrum-selectivity, materials, and productivity. A discussion is finally presented concerning future development of photo-thermal catalytic reactions with spectrum-selectivity.

关键词： photo-thermal catalysis     spectrum-selectivity     solar fuel     full-spectrum    

HTML PDF 收藏

Enhancing the aromatic selectivity of cyclohexane aromatization by CO2 coupling

《化学科学与工程前沿（英文）》 2023年 第17卷 第11期   页码 1801-1808 doi: 10.1007/s11705-023-2325-9

摘要： Improving the aromatic selectivity in the alkane aromatization process is of great importance for its practical utilization but challenge to make because the high H/C ratio of alkanes would lead to a serious hydrogen transfer process and a large amount of light alkanes. Herein, CO2 is introduced into the cyclohexane conversion process on the HZSM-5 zeolite, which can improve the aromatic selectivity. By optimizing the reaction conditions, an improved aromatic (benzene, toluene, xylene, and C9+) selectivity of 48.2% can be obtained at the conditions of 2.7 MPa (CO2), 450 °C, and 1.7 h−1, which is better than that without CO2 (aromatic selectivity = 43.2%). In situ transmission Fourier transform infrared spectroscopy spectra illustrate that many oxygenated chemical intermediates (e.g., carboxylic acid, anhydride, unsaturated aldehydes/ketones or ketene) would be formed during the cyclohexane conversion process in the presence of CO2. 13C isotope labeling experimental results demonstrate that CO2 can enter into the aromatics through the formation of oxygenated chemical intermediates and thereby improve the aromatic selectivity. This study may open a green, economic, and promising way to improve the aromatic selectivity for alkane aromatization process.

关键词： aromatics     carbon dioxide     aromatization     coupling reaction     ZSM-5 zeolite    

HTML PDF 收藏

Non-toxic, high selectivity process for the extraction of precious metals from waste printed circuit

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1723-z

摘要：

● Au, Ag and Pd were recovered from WPCBs with high efficiencies.

关键词： Thiosulfate     Printed circuit boards     Precious metals     Leaching     Hydrometallurgy    

HTML PDF 收藏

A Miniature Meta-Optical System for Reconfigurable Wide-Angle Imaging and Polarization-Spectral Detection

Fei Zhang,Minghao Liao,Mingbo Pu,Yinghui Guo,Lianwei Chen,Xiong Li,Qiong He,Tongtong Kang,Xiaoliang Ma,Yuan Ke,Xiangang Luo,

《工程（英文）》 doi: 10.1016/j.eng.2023.07.008

摘要： Wide-angle imaging and spectral detection play vital roles in tasks such as target tracking, object classification, and anti-camouflage. However, limited by their intrinsically different architectures, as determined by frequency dispersion requirements, their simultaneous implementation in a shared-aperture system is difficult. Here, we propose a novel concept to realize reconfigurable dual-mode detection based on electrical-control tunable metasurfaces. As a proof-of-concept demonstration, the simultaneous implementation of wide-angle imaging and polarization-spectral detection in a miniature shared-aperture meta-optical system is realized for the first time via the electrical control of cascaded catenary-like metasurfaces. The proposed system supports the imaging (spectral) resolution of approximately 27.8 line-pairs per millimeter (lp·mm−1; ∼80 nm) for an imaging (spectral) mode from 8 to 14 μm. This system also bears a large field of view of about 70°, enabling multi-target recognition in both modes. This work may promote the miniaturization of multifunctional optical systems, including spectrometers and polarization imagers, and illustrates the potential industrial applications of meta-optics in biomedicine, security, space exploration, and more.

关键词： Metasurfaces     Reconfigurable     Imaging     Spectral    

HTML PDF 收藏

Nongray radiation from gas and soot mixtures in planar plates based on statistical narrow-band spectral

Huaqiang CHU, Qiang CHENG, Huaichun ZHOU, Fengshan LIU

《能源前沿（英文）》 2011年 第5卷 第2期   页码 149-158 doi: 10.1007/s11708-010-0124-8

摘要： The nongray behavior of combustion products plays an important role in various areas of engineering. Based on the statistical narrow-band (SNB) spectral model with an exponential-tailed inverse intensity distribution and the ray-tracing method, a comprehensive investigation of the influence of soot on nongray radiation from mixtures containing H O/N +soot, CO /N +soot, or H O/CO /N +soot was conducted in this paper. In combustion applications, radiation transfer is significantly enhanced by soot due to its spectrally continuous emission. The effect of soot volume fraction up to 1×10 on the source term, the narrow-band radiation intensities along a line-of-sight, and the net wall heat fluxes were investigated for a wide range of temperature. The effect of soot was significant and became increasingly drastic with the increase of soot loading.

关键词： soot     combustion     SNB model     nongray radiation    

HTML PDF 收藏

Application of spectral technology in flame measurement

Jiaxun LIU, Xiaoshu CAI, Zenghao ZHU, Huinan YANG

《能源前沿（英文）》 2014年 第8卷 第1期   页码 138-143 doi: 10.1007/s11708-013-0283-5

摘要： Spectral technology has become an important detection method due to its advantages such as non-intrusive measurement and on-line analysis. In this paper, two applications of spectral technology in thermal detection were proposed. First, a novel spectroscopic method based on Planck’s law for measurement of emissivity was introduced. The emissivity, obtained by comparing the radiation intensity of the blackbody which had the same temperature as the flame with the detected intensity of the flames, could be used for on-line measurements and had a relatively higher upper temperature limit. Then, a spectroscopic method for composition detection of blended fuels was proposed based on the emissivity measured. By comparing the spectra of blended fuels and single fuels, the ratio of single fuels of the blended fuel could be calculated. The measurement system proposed in this paper, which consists of a spectrometer and a computer, is very compact.

关键词： spectrum     emissivity measurement     component of fuel     near-infrared spectrometer    

HTML PDF 收藏

Spectral characteristics of plant communities from salt marshes: A case study from Chongming Dongtan,

ZHANG Liquan, GAO Zhanguo, Armitage Richard, Kent Martin

《环境科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 187-197 doi: 10.1007/s11783-008-0004-1

摘要： The spectral reflectance of recently formed salt marshes at the mouth of the Yangtze River, which are undergoing invasion by , were assessed to determine the potential utility of remotely sensed data in assessing future invasion and changes in species composition. Following a review of published research on remote sensing of salt marshes, 53 locations along three transects were sampled for paired data on plant species composition and spectral reflectance using a FieldSpec Pro JR Field Portable Spectroradiometer. Spectral data were processed concerning reflectance, and the averaged reflectance values for each sample were re-analysed to correspond to a 12-waveband bandset of the Compact Airborne Spectral Imager. The spectral data were summarised using principal components analysis (PCA) and the relationships between the vegetation composition, and the PCA axes of spectral data were examined. The first PCA axis of the reflectance data showed a strong correlation with variability in near infrared reflectance and ‘brightness’, while the second axis was correlated with visible reflectance and ‘greenness’. Total vegetation cover, vegetation height, and mudflat cover were all significantly related to the first axis. The implications of this in terms of the ability of remote sensing to distinguish the various salt marsh species and in particular the invasive species were discussed. Major differences in species with various physiognomies could be recognised but problems occurred in separating early colonising from other species at that stage. Further work using multi-seasonal hyperspectral data might assist in solving these problems.

关键词： Spectral     multi-seasonal hyperspectral     invasive     JR     re-analysed    

HTML PDF 收藏

Spectral element modeling based structure piezoelectric impedance computation and damage identification

Zhigang GUO, Zhi SUN

《结构与土木工程前沿（英文）》 2011年 第5卷 第4期   页码 458-464 doi: 10.1007/s11709-011-0133-7

摘要： This paper presents a numerical simulation study on electromechanical impedance technique for structural damage identification. The basic principle of impedance based damage detection is structural impedance will vary with the occurrence and development of structural damage, which can be measured from electromechanical admittance curves acquired from PZT patches. Therefore, structure damage can be identified from the electromechanical admittance measurements. In this study, a model based method that can identify both location and severity of structural damage through the minimization of the deviations between structural impedance curves and numerically computed response is developed. The numerical model is set up using the spectral element method, which is promised to be of high numerical efficiency and computational accuracy in the high frequency range. An optimization procedure is then formulated to estimate the property change of structural elements from the electric admittance measurement of PZT patches. A case study on a pin-pin bar is conducted to investigate the feasibility of the proposed method. The results show that the presented method can accurately identify bar damage location and severity even when the measurements are polluted by 5% noise.

关键词： PZT     piezoelectric impedance     optimization     spectral element     damage identification    

HTML PDF 收藏

Catalysis of semihydrogenation of acetylene to ethylene: current trends, challenges, and outlook

《化学科学与工程前沿（英文）》 2022年 第16卷 第7期   页码 1031-1059 doi: 10.1007/s11705-021-2113-3

摘要： Ethylene is an important feedstock for various industrial processes, particularly in the polymer industry. Unfortunately, during naphtha cracking to produce ethylene, there are instances of acetylene presence in the product stream, which poisons the Ziegler–Natta polymerization catalysts. Thus, appropriate process modification, optimization, and in particular, catalyst design are essential to ensure the production of highly pure ethylene that is suitable as a feedstock in polymerization reactions. Accordingly, carefully selected process parameters and the application of various catalyst systems have been optimized for this purpose. This review provides a holistic view of the recent reports on the selective hydrogenation of acetylene. Previously published reviews were limited to Pd catalysts. However, effective new metal and non-metal catalysts have been explored for selective acetylene hydrogenation. Updates on this recent progress and more comprehensive computational studies that are now available for the reaction are described herein. In addition to the favored Pd catalysts, other catalyst systems including mono, bimetallic, trimetallic, and ionic catalysts are presented. The specific role(s) that each process parameter plays to achieve high acetylene conversion and ethylene selectivity is discussed. Attempts have been made to elucidate the possible catalyst deactivation mechanisms involved in the reaction. Extensive reports suggest that acetylene adsorption occurs through an active single-site mechanism rather than via dual active sites. An increase in the reaction temperature affords high acetylene conversion and ethylene selectivity to obtain reactant streams free of ethylene. Conflicting findings to this trend have reported the presence of ethylene in the feed stream. This review will serve as a useful resource of condensed information for researchers in the field of acetylene-selective hydrogenation.

关键词： selectivity     hydrogenation     acetylene     ethylene     palladium    

HTML PDF 收藏

Transport and selectivity of indium through polymer inclusion membrane in hydrochloric acid medium

Xiaorong Meng, Conghui Wang, Pan Zhou, Xiaoqiang Xin, Lei Wang

《环境科学与工程前沿（英文）》 2017年 第11卷 第6期 doi: 10.1007/s11783-017-0950-6

摘要： In the present paper, a polymer inclusion membrane (PIM) containing polyvinyl chloride (PVC), and bis-(2-ethylhexyl) phosphate (D2EHPA) which was used as extracting agent was used for the recovery of In(III) ions in hydrochloric acid medium. The effects of carrier concentration, feed phase pH, strip phase HCl concentration, temperature on the transport, and the membrane’s stability and thickness were examined. And the conditions for the selective separation of In(III) and Cu(II) were optimized. The results showed that the transport of In(III) across PIM was consistent with the first order kinetics equation, and also it was controlled by both the diffusion of the metal complex in the membrane and the chemical reaction at the interface of the boundary layers. The transport flux ( ) was inversely proportional to the membrane thickness, however, the transport stability improved as the membrane thickness increased. The transport flux of In(III) and Cu(II) was decreased by excessive acidity of feed phase and high concentration of Cl . The selectivity separation coefficient of In(III)/Cu(II) was up to 34.33 when the original concentration of both In(III) and Cu(II) was 80 mg·L as well as the pH of the feed phase and the concentration of Cl in the adjusting context were0.6 and 0.5 mol·L , respectively. Within the range of pH= 1–3, the separation selectivity of In(III)/Cu(II) reached the peak in the case when the Cl concentration was 0.7 mol·L .

关键词： Polymer inclusion membrane     Selective transport     D2EHPA     In(III)     Cu(II)    

HTML PDF 收藏

标题 作者 时间 类型 操作

A spectrally selective surface structure for combined photothermic conversion and radiative sky cooling

Bin ZHAO, Xianze AO, Nuo CHEN, Qingdong XUAN, Mingke HU, Gang PEI

期刊论文

Tuning the catalytic selectivity in electrochemical CO

Jiafang XIE,Yuxi HUANG,Hanqing YU

期刊论文

An investigation of the CHOH and CO selectivity of CO hydrogenation over Cu–Ce–Zr catalysts

期刊论文

Applying the spectral stochastic finite element method in multiple-random field RC structures

Abbas YAZDANI

期刊论文

Fault feature extraction of planet gear in wind turbine gearbox based on spectral kurtosis and time wavelet

Yun KONG, Tianyang WANG, Zheng LI, Fulei CHU

期刊论文

Solar fuel from photo-thermal catalytic reactions with spectrum-selectivity: a review

Sanli TANG, Jie SUN, Hui HONG, Qibin LIU

期刊论文

Enhancing the aromatic selectivity of cyclohexane aromatization by CO2 coupling

期刊论文

Non-toxic, high selectivity process for the extraction of precious metals from waste printed circuit

期刊论文

A Miniature Meta-Optical System for Reconfigurable Wide-Angle Imaging and Polarization-Spectral Detection

Fei Zhang,Minghao Liao,Mingbo Pu,Yinghui Guo,Lianwei Chen,Xiong Li,Qiong He,Tongtong Kang,Xiaoliang Ma,Yuan Ke,Xiangang Luo,

期刊论文

Nongray radiation from gas and soot mixtures in planar plates based on statistical narrow-band spectral

Huaqiang CHU, Qiang CHENG, Huaichun ZHOU, Fengshan LIU

期刊论文

Application of spectral technology in flame measurement

Jiaxun LIU, Xiaoshu CAI, Zenghao ZHU, Huinan YANG

期刊论文

Spectral characteristics of plant communities from salt marshes: A case study from Chongming Dongtan,

ZHANG Liquan, GAO Zhanguo, Armitage Richard, Kent Martin

期刊论文

Spectral element modeling based structure piezoelectric impedance computation and damage identification

Zhigang GUO, Zhi SUN

期刊论文

Catalysis of semihydrogenation of acetylene to ethylene: current trends, challenges, and outlook

期刊论文

Transport and selectivity of indium through polymer inclusion membrane in hydrochloric acid medium

Xiaorong Meng, Conghui Wang, Pan Zhou, Xiaoqiang Xin, Lei Wang

期刊论文