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Performance evaluation of an improved biomass-fired cogeneration system simultaneously using extraction

《能源前沿（英文）》 2022年 第16卷 第2期   页码 321-335 doi: 10.1007/s11708-021-0741-4

摘要： An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the turbine, the cooling water from the plant condenser, and the low-pressure feedwater from the feedwater preheating system were collectively used for producing district heat in the new scheme. Hence, a remarkable energy-saving effect could be achieved, improving the overall efficiency of the cogeneration system. The thermodynamic and economic performance of the novel system was examined when taking a 35 MW biomass-fired cogeneration unit for case study. Once the biomass feed rate and net thermal production remain constant, an increment of 1.36 MW can be expected in the net electric production, because of the recommended upgrading. Consequently, the total system efficiency and effective electrical efficiency augmented by 1.23 and 1.50 percentage points. The inherent mechanism of performance enhancement was investigated from the energy and exergy aspects. The economic study indicates that the dynamic payback period of the retrofitting project is merely 1.20 years, with a net present value of 5796.0 k$. In conclusion, the proposed concept is validated to be advantageous and profitable.

关键词： biomass-fired cogeneration     district heat production system     absorption heat pump     extraction steam     cooling water     low-pressure feedwater    

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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    

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Entity and relation extraction with rule-guided dictionary as domain knowledge

《工程管理前沿（英文）》   页码 610-622 doi: 10.1007/s42524-022-0226-0

摘要： Entity and relation extraction is an indispensable part of domain knowledge graph construction, which can serve relevant knowledge needs in a specific domain, such as providing support for product research, sales, risk control, and domain hotspot analysis. The existing entity and relation extraction methods that depend on pretrained models have shown promising performance on open datasets. However, the performance of these methods degrades when they face domain-specific datasets. Entity extraction models treat characters as basic semantic units while ignoring known character dependency in specific domains. Relation extraction is based on the hypothesis that the relations hidden in sentences are unified, thereby neglecting that relations may be diverse in different entity tuples. To address the problems above, this paper first introduced prior knowledge composed of domain dictionaries to enhance characters’ dependence. Second, domain rules were built to eliminate noise in entity relations and promote potential entity relation extraction. Finally, experiments were designed to verify the effectiveness of our proposed methods. Experimental results on two domains, including laser industry and unmanned ship, showed the superiority of our methods. The F1 value on laser industry entity, unmanned ship entity, laser industry relation, and unmanned ship relation datasets is improved by +1%, +6%, +2%, and +1%, respectively. In addition, the extraction accuracy of entity relation triplet reaches 83% and 76% on laser industry entity pair and unmanned ship entity pair datasets, respectively.

关键词： entity extraction     relation extraction     prior knowledge     domain rule    

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An extraction- assay system: Evaluation on flavonols in plant resistance to Pb and Cd by supercriticalextraction- gas chromatography

Xu Zhang, Huanhuan Yang, Xinlei Wang, Wen Song, Zhaojie Cui

《环境科学与工程前沿（英文）》 2018年 第12卷 第4期 doi: 10.1007/s11783-018-1059-2

摘要：

SFE-GC system is established for flavonols assessment.

Optimal parameters of SFE-GC are evaluated and determined.

Quercetin and kaempferol are detected in plant under heavy metal stress.

Gene expression analysis shows consistent regularity with content of flavonols.

ROS level is applied for elaborating the plant resistance status.

关键词： Flavonols     Heavy metal     Supercritical carbon dioxide extraction (SFE)     GC     Plant resistance    

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Feature extraction from slice data for reverse engineering

ZHANG Yingjie, LU Shangning

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 25-31 doi: 10.1007/s11465-007-0004-z

摘要： A new approach to feature extraction for slice data points is presented. The reconstruction of objects is performed as follows. First, all contours in each slice are extracted by contour tracing algorithms. Then the data points on the contours are analyzed, and the curve segments of the contours are divided into three categories: straight lines, conic curves and B-spline curves. The curve fitting methods are applied for each curve segment to remove the unwanted points with pre-determined tolerance. Finally, the features, which consist of the object and connection relations among them, are founded by matching the corresponding contours in adjacent slices, and 3D models are reconstructed based on the features. The proposed approach has been implemented in OpenGL, and the feasibility of the proposed method has been verified by several cases.

关键词： feasibility     corresponding     B-spline     pre-determined tolerance     extraction    

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A microextraction approach for rapid extraction and separation of Mn(II) and Co(II) using saponified

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 963-972 doi: 10.1007/s11705-021-2081-7

摘要： In this paper, we proposed a microextraction approach for the extraction and separation of Mn(II) and Co(II) from sulfate solution simulating leachate of spent lithium-ion battery cathode materials using saponified di-(2-ethylhexyl)phosphoric acid system. The effects of the following operational variables were investigated: equilibrium pH, tri-n-butyl phosphate concentration, saponification rate, two-phase ratio and residence time. The results showcased that the microextractor can reach the extraction equilibrium within 20 s, thereby greatly reducing necessary extraction time comparing to that of conventional processes. The volumetric mass transfer coefficient showed 8–21 times larger than that of batch device. With the help of microextractor, 95% of Mn(II) was extracted with a single theoretical stage at a chosen two-phase ratio of 3:1, and the separation factor βMn/Co was as large as 65.5. In the subsequent stripping step, more than 99% of manganese from loaded phase was easily stripped under optimal conditions. The microextraction approach greatly enhances the mass transfer while enabling a continuous and controllable extraction process within a simple structure design. When extracting spent electrode material with microextractors, the comprehensive recovery of mangenese can reach 96%. The microextraction approach has a good applicability in the spent lithium-ion battery cathode materials recycling at both bench and industrial scales.

关键词： extraction equilibrium     mass transfer coefficient     microextraction     multicomponent extraction     di-(2-ethylhexyl)phosphoric acid    

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Absorption heat pump for waste heat reuse: current states and future development

Zhenyuan XU, Ruzhu WANG

《能源前沿（英文）》 2017年 第11卷 第4期   页码 414-436 doi: 10.1007/s11708-017-0507-1

摘要： Absorption heat pump attracts increasing attention due to its advantages in low grade thermal energy utilization. It can be applied for waste heat reuse to save energy consumption, reduce environment pollution, and bring considerable economic benefit. In this paper, three important aspects for absorption heat pump for waste heat reuse are reviewed. In the first part, different absorption heat pump cycles are classified and introduced. Absorption heat pumps for heat amplification and absorption heat transformer for temperature upgrading are included. Both basic single effect cycles and advanced cycles for better performance are introduced. In the second part, different working pairs, including the water based working pairs, ammonia based working pairs, alcohol based working pairs, and halogenated hydrocarbon based working pairs, for absorption heat pump are classified based on the refrigerant. In the third part, the applications of the absorption heat pump and absorption heat transformer for waste heat reuse in different industries are introduced. Based on the reviews in the three aspects, essential summary and future perspective are presented at last.

关键词： absorption     heat pump     heat transformer     waste heat     working pair    

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Study of an artificial boundary condition based on the damping-solvent extraction method

Qiang XU, Jianyun CHEN, Jing LI, Mingming WANG

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 281-287 doi: 10.1007/s11709-012-0167-5

摘要： A new artificial boundary condition for time domain analysis of a structure-unlimited-foundation system was proposed. The boundary condition was based on the damping-solvent extraction method. The principle of the damping-solvent extraction method was described. An artificial boundary condition was then established by setting two spring-damper systems and one artificial damping limited region. A test example was developed to verify that the proposed boundary condition and model had high precision. Compared with the damping-solvent extraction method, this boundary condition is easier to be applied to finite element method (FEM)-based numerical calculations.

关键词： damping-solvent extraction method     structure-unlimited-foundation system     spring-damper system     artificial damping limited region     finite element method    

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Study on the microwave-assisted extraction of polyphenols from tea

Liyun WANG, Peiyong QIN, Yan HU,

《化学科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 307-313 doi: 10.1007/s11705-009-0282-6

摘要： This study demonstrated a promising method for quickly extracting tea polyphenol (TP) by microwave-assisted extraction (MAE) technology. Some influential parameters, including MAE temperature, microwave power, concentration of extraction solvent, MAE time and the solid/liquid ratio, were investigated. The optimum condition of MAE was obtained by dual extraction with 60% ethanol (v/v) and the solid/liquid ratio 1:12 g/mL at 80°C for 10 minutes under the microwave power 600 W. The yield of TP was 96.5% under the described condition. Compared with traditional methods, including hot reflux extraction (HRE), ultrasound-assisted extraction (UAE) and supercritical fluid extraction (SFE), the extraction time was saved 8 times than that of HRE, and the yield was increased by 17.5%. The extraction time at comparable levels of production was saved 2 times, and the energy consumption was one fourth that of UAE. The extraction time was saved 5 times than that of SFE, and the yield of TP was increased by 40%. Moreover, compared with MAE of TP studied by others, it decreased the solid/liquid ratio from 1 ∶ 20 to 1 ∶ 12 g/mL without 90-min pre-leaching time, and the yield of TP was increased by 6%–40%.

关键词： energy consumption     microwave-assisted extraction     optimum condition     pre-leaching     concentration    

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Oxidation-extraction desulfurization of model oil over Zr-ZSM-5/SBA-15 and kinetic study

Chuanzhu LU,Hui FU,Huipeng LI,Hua ZHAO,Tianfeng CAI

《化学科学与工程前沿（英文）》 2014年 第8卷 第2期   页码 203-211 doi: 10.1007/s11705-014-1420-3

摘要： ZSM-5/SBA-15 composite molecular sieves were synthesized using post-synthesis method and characterized by X-ray diffraction and N adsorption-desorption. The oxidative-extration desulfurization of model oil was investigated by using hydrogen peroxide as the oxidant, tetrabutyl ammonium bromide as phase transfer catalyst, dimethyl sulfoxide as extractant, and Zr-ZSM-5/SBA-15, Ag-ZSM-5/SBA-15, Ce-ZSM-5/SBA-15 as catalyst. Under the optimal conditions, the desulfurization rate decreases in the order: Zr-ZSM-5/SBA-15>Ce-ZSM-5/SBA-15>Ag-ZSM-5/SBA-15. The highest desulfurization rate is 84.53% under the catalysis of Zr-ZSM-5/SBA-15. Kinetics analysis shows that the reaction is pseudo-first-order with the activation energy of 44.23 kJ/mol.

关键词： composite molecular sieve     oxidation desulfuration     extraction     kinetic    

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Extraction of hydrogen chloride by a coupled reaction-solvent extraction process

Yunzhao Li,Xingfu Song,Guilan Chen,Shuying Sun,Yanxia Xu,Jianguo Yu

《化学科学与工程前沿（英文）》 2015年 第9卷 第4期   页码 479-487 doi: 10.1007/s11705-015-1512-8

摘要： A coupled reaction-solvent extraction process was used to remove HCl from a simulated distiller waste. The extraction performances of various extractants and diluents were compared and the apparent basicity of N235 (a mixture of tertiary amines) in various diluents was determined. The best results were obtained using N235 and isoamyl alcohol as the extractant and diluent, respectively. The yield of HCl from the coupled extraction was 75% with this extraction system. The mechanisms for the removal of HCl in both the direct and coupled extractions were investigated. For the coupled extraction, the formation of an R NHCl ion-pair complex was involved in the HCl removal. For the direct extraction, the mechanism involved the formation of hydrogen bonds at high concentrations of HCl.

关键词： hydrogen chloride     distiller waste     coupled reaction and solvent extraction     N235     extraction mechanism    

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Surface molecularly imprinted polymers for solid-phase extraction of (--)-epigallocatechin gallate from

Yunling Gao,Ying Hu,Kejian Yao

《化学科学与工程前沿（英文）》 2015年 第9卷 第4期   页码 467-478 doi: 10.1007/s11705-015-1526-2

摘要： Surface molecularly imprinted polymers (SMIPs) have been synthesized to selectively determine (−)-epigallocatechin gallate in aqueous media. SMIPs were prepared using a surface grafting copolymerization method on a functionalized silica gel modified with -cyclodextrin and vinyl groups. The morphology and composition of the SMIPs were investigated by scanning electron microscopy, Fourier transform-infrared spectroscopy and thermogravimetric analysis. In addition, the molecular binding capacity, recognition properties and selectivity of the SMIPs were evaluated. The imprinted polymers were found to have a highly specific recognition and binding capacity for (−)-epigallocatechin gallate in aqueous media which is the result of the hydrophobic properties of the -cyclodextrin and the hydrogen-bonding interactions of methacrylic acid. The SMIPs were successfully employed as solid-phase extraction adsorbents prior to the HPLC determination of (−)-epigallocatechin gallate in toothpaste. The HPLC analysis had a linear dynamic range of 0.5–50.0 µg?mL with a correlation coefficient of 0.9998 and the recoveries ranged from 89.4% to 97.0% with relative standard deviations less than 4.8%. The limit of detection and limit of quantification were 0.17 and 0.33 µg?mL , respectively. The method provides a promising approach for the preparation of selective materials for the purification and determination of complex samples.

关键词： β-cyclodextrin     (−)-epigallocatechin gallate     surface molecular imprinting     solid-phase extraction    

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Effects of radiation and heat source/sink on unsteady MHD boundary layer flow and heat transfer over

Krishnendu Bhattacharyya

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 376-384 doi: 10.1007/s11705-011-1121-0

摘要： In this paper, an investigation is made to study the effects of radiation and heat source/sink on the unsteady boundary layer flow and heat transfer past a shrinking sheet with suction/injection. The flow is permeated by an externally applied magnetic field normal to the plane of flow. The self-similar equations corresponding to the velocity and temperature fields are obtained, and then solved numerically by finite difference method using quasilinearization technique. The study reveals that the momentum boundary layer thickness increases with increasing unsteadiness and decreases with magnetic field. The thermal boundary layer thickness decreases with Prandtl number, radiation parameter and heat sink parameter, but it increases with heat source parameter. Moreover, increasing unsteadiness, magnetic field strength, radiation and heat sink strength boost the heat transfer.

关键词： MHD boundary layer     unsteady flow     heat transfer     thermal radiation     heat source/sink     shrinking sheet     suction/injection    

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Acoustic fault signal extraction via the line-defect phononic crystals

《机械工程前沿（英文）》 2022年 第17卷 第1期   页码 10-10 doi: 10.1007/s11465-021-0666-y

摘要： Rotating machine fault signal extraction becomes increasingly important in practical engineering applications. However, fault signals with low signal-to-noise ratios (SNRs) are difficult to extract, especially at the early stage of fault diagnosis. In this paper, 2D line-defect phononic crystals (PCs) consisting of periodic acrylic tubes with slit are proposed for weak signal detection. The defect band, namely, the formed resonance band of line-defect PCs enables the incident acoustic wave at the resonance frequency to be trapped and enhanced at the resonance cavity. The noise can be filtered by the band gap. As a result, fault signals with high SNRs can be obtained for fault feature extraction. The effectiveness of weak harmonic and periodic impulse signal detection via line-defect PCs are investigated in numerical and experimental studies. All the numerical and experimental results indicate that line-defect PCs can be well used for extracting weak harmonic and periodic impulse signals. This work will provide potential for extracting weak signals in many practical engineering applications.

关键词： phononic crystals     line-defect     fault signal extraction     acoustic enhancement    

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nitrogen-doped carbon cladding LiMnO film electrode with enhanced stability for electrochemically selective extraction

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2050-2060 doi: 10.1007/s11705-023-2343-7

摘要： Reducing the dissolution of Mn from LiMn2O4 (LMO) and enhancing the stability of film electrodes are critical and challenging for Li+ ions selective extraction via electrochemically switched ion exchange technology. In this work, we prepared a nitrogen-doped carbon cladding LMO (C-N@LMO) by polymerization of polypyrrole and high-temperature annealing in the N2 gas to achieve the above purpose. The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode. The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42% compared to the LMO film electrode after 10 cycles. The cladding layer not only acted as a protective layer but also functioned as a conductive shell, accelerating the migration rate of Li+ ions. The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li+ ions, which was 33% less compared to the pure LMO film electrode. Meanwhile, the C-N@LMO film electrode retained evident selectivity toward Li+ ions, and the separation factor was 118.38 for Li+ toward Mg2+ in simulated brine. Therefore, the C-N@LMO film electrode would be a promising candidate for the recovery of Li+ ions from salt lakes.

关键词： LiMn2O4     lithium extraction     surface coating     cyclic stability     Mn dissolution    

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标题 作者 时间 类型 操作

Performance evaluation of an improved biomass-fired cogeneration system simultaneously using extraction

期刊论文

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

Entity and relation extraction with rule-guided dictionary as domain knowledge

期刊论文

An extraction- assay system: Evaluation on flavonols in plant resistance to Pb and Cd by supercriticalextraction- gas chromatography

Xu Zhang, Huanhuan Yang, Xinlei Wang, Wen Song, Zhaojie Cui

期刊论文

Feature extraction from slice data for reverse engineering

ZHANG Yingjie, LU Shangning

期刊论文

A microextraction approach for rapid extraction and separation of Mn(II) and Co(II) using saponified

期刊论文

Absorption heat pump for waste heat reuse: current states and future development

Zhenyuan XU, Ruzhu WANG

期刊论文

Study of an artificial boundary condition based on the damping-solvent extraction method

Qiang XU, Jianyun CHEN, Jing LI, Mingming WANG

期刊论文

Study on the microwave-assisted extraction of polyphenols from tea

Liyun WANG, Peiyong QIN, Yan HU,

期刊论文

Oxidation-extraction desulfurization of model oil over Zr-ZSM-5/SBA-15 and kinetic study

Chuanzhu LU,Hui FU,Huipeng LI,Hua ZHAO,Tianfeng CAI

期刊论文

Extraction of hydrogen chloride by a coupled reaction-solvent extraction process

Yunzhao Li,Xingfu Song,Guilan Chen,Shuying Sun,Yanxia Xu,Jianguo Yu

期刊论文

Surface molecularly imprinted polymers for solid-phase extraction of (--)-epigallocatechin gallate from

Yunling Gao,Ying Hu,Kejian Yao

期刊论文

Effects of radiation and heat source/sink on unsteady MHD boundary layer flow and heat transfer over

Krishnendu Bhattacharyya

期刊论文

Acoustic fault signal extraction via the line-defect phononic crystals

期刊论文

nitrogen-doped carbon cladding LiMnO film electrode with enhanced stability for electrochemically selective extraction

期刊论文