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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    

An exploratory study for predicting component reliability with new load conditions

Zhengwei HU, Xiaoping DU

《机械工程前沿(英文)》 2019年 第14卷 第1期   页码 76-84 doi: 10.1007/s11465-018-0522-x

摘要: Reliability is important to design innovation. A new product should be not only innovative, but also reliable. For many existing components used in the new product, their reliability will change because the applied Loads are different from the ones for which the components are originally designed and manufactured. Then the new reliability must be re-evaluated. The system designers of the new product, however, may not have enough information to perform this task. With a beam problem as a case study, this study explores a feasible way to re-evaluate the component reliability with new Loads given the following information: The original reliability of the component with respect to the component Loads and the distributions of the new component Loads. Physics-based methods are employed to build the equivalent component limit-state function that can predict the component failure under the new Loads. Since the information is limited, the re-evaluated component reliability is given by its maximum and minimum values. The case study shows that good accuracy can be obtained even though the new reliability is provided with the aforementioned interval.

关键词: reliability     component     failure mode     prediction     random variable    

Improved resilience measure for component recovery priority in power grids

《工程管理前沿(英文)》 2021年 第8卷 第4期   页码 545-556 doi: 10.1007/s42524-021-0161-5

摘要: Given the complexity of power grids, the failure of any component may cause large-scale economic losses. Consequently, the quick recovery of power grids after disasters has become a new research direction. Considering the severity of power grid disasters, an improved power grid resilience measure and its corresponding importance measures are proposed. The recovery priority of failed components after a disaster is determined according to the influence of the failed components on the power grid resilience. Finally, based on the data from the 2019 Power Yearbook of each city in Shandong Province, China, the power grid resilience after a disaster is analyzed for two situations, namely, partial components failure and failure of all components. Result shows that the recovery priorities of components with different importance measures vary. The resilience evaluations under different repair conditions prove the feasibility of the proposed method.

关键词: resilience measure     power grid     importance measure     component recovery    

Molecular level simulations on multi-component systems —a morphology prediction method

C. SCHMIDT, J. ULRICH

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 49-54 doi: 10.1007/s11705-013-1307-8

摘要: The crystal morphology grown from a solution composed of an organic solvent, solute and additive can be predicted reliably by a computational method. Modeling the supersaturated solution as liquid phase is achieved by employing commercial software. The molecular composition of this solution is a required input parameter. The face specific diffusion coefficient of the solid (crystal surface) and liquid (solution) system is determined using the molecular dynamics procedure. The obtained diffusion coefficient is related to the specific face growth rate via the attachment energy of the pure morphology. The significant improvements are achieved in the morphology prediction because the investigation on the face growth rates in a complex growth environment (as multi-component solutions with additives) can be carried out based on the diffusion coefficients.

关键词: crystallization     morphology     molecular dynamics     solution    

Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web component

Ke WEI, Xiaoguang FAN, Mei ZHAN, Miao MENG

《机械工程前沿(英文)》 2018年 第13卷 第3期   页码 376-384 doi: 10.1007/s11465-018-0500-3

摘要:

Billet optimization can greatly improve the forming quality of the transitional region in the isothermal local loading forming (ILLF) of large-scale Ti-alloy rib-web components. However, the final quality of the transitional region may be deteriorated by uncontrollable factors, such as the manufacturing tolerance of the preforming billet, fluctuation of the stroke length, and friction factor. Thus, a dual-response surface method (RSM)-based robust optimization of the billet was proposed to address the uncontrollable factors in transitional region of the ILLF. Given that the die underfilling and folding defect are two key factors that influence the forming quality of the transitional region, minimizing the mean and standard deviation of the die underfilling rate and avoiding folding defect were defined as the objective function and constraint condition in robust optimization. Then, the cross array design was constructed, a dual-RSM model was established for the mean and standard deviation of the die underfilling rate by considering the size parameters of the billet and uncontrollable factors. Subsequently, an optimum solution was derived to achieve the robust optimization of the billet. A case study on robust optimization was conducted. Good results were attained for improving the die filling and avoiding folding defect, suggesting that the robust optimization of the billet in the transitional region of the ILLF was efficient and reliable.

关键词: isothermal local loading forming     rib-web component     transitional region     robust optimization     dual response surface method    

Development of a multi-component drug from turmeric using central composite design

Xiaohang ZHANG,Shengnan HAN,Yan LI,Jianlan JIANG

《化学科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 362-368 doi: 10.1007/s11705-014-1439-5

摘要: A methodology to develop multi-component drugs based on traditional Chinese medicines has been developed using central composite design. Several active components from the traditional Chinese medicine turmeric were chosen for use in a multi-component antitumor drug. Response surface methodology based on a central composite design was applied to determine the quantitative composition-activity relationships in order to optimize the amount of each component in the drug. An MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to measure the pharmacological activity as the response value. The experimental antitumor activity of the optimum combination was 92.85% in the MTT assay and superior to the activities of each single component. These results demonstrate that response surface methodology based on a central composite design is suitable for the design of multi-component drugs.

关键词: multi-component drug development     central composite design     turmeric     curcuminoids    

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

《能源前沿(英文)》 2023年 第17卷 第5期   页码 664-677 doi: 10.1007/s11708-021-0787-3

摘要: The combustion characteristics and emission behaviors of RP-3 jet fuel were studied and compared to commercial diesel fuel in a single-cylinder compression ignition (CI) engine. Engine operational parameters, including engine load (0.6, 0.7, and 0.8 MPa indicating the mean effective pressure (IMEP)), the exhaust gas recirculation (EGR) rate (0%, 10%, 20%, and 30%), and the fuel injection timing (−20, −15, −10, and −5 ° crank angle (CA) after top dead center (ATDC)) were adjusted to evaluate the engine performances of RP-3 jet fuel under changed operation conditions. In comparison to diesel fuel, RP-3 jet fuel shows a retarded heat release and lagged combustion phase, which is more obvious under heavy EGR rate conditions. In addition, the higher premixed combustion fraction of RP-3 jet fuel leads to a higher first-stage heat release peak than diesel fuel under all testing conditions. As a result, RP-3 jet fuel features a longer ignition delay (ID) time, a shorter combustion duration (CD), and an earlier CA50 than diesel fuel. The experimental results manifest that RP-3 jet fuel has a slightly lower indicated thermal efficiency (ITE) compared to diesel fuel, but the ITE difference becomes less noticeable under large EGR rate conditions. Compared with diesel fuel, the nitrogen oxides (NOx) emissions of RP-3 jet fuel are higher while its soot emissions are lower. The NOx emissions of RP-3 can be effectively reduced with the increased EGR rate and delayed injection timing.

关键词: RP-3 jet fuel     diesel     engine     combustion     emissions    

Impacts of methanol fuel on vehicular emissions: A review

《环境科学与工程前沿(英文)》 2022年 第16卷 第9期 doi: 10.1007/s11783-022-1553-4

摘要:

● Methanol effectively reduces CO, HC, CO2, PM, and PN emissions of gasoline vehicles.

关键词: Methanol fuel     Vehicular emission     Emission reduction     Cleaner fuel     Gasoline substitute    

Non-negativematrix factorization based unmixing for principal component transformed hyperspectral data

Xiu-rui GENG,Lu-yan JI,Kang SUN

《信息与电子工程前沿(英文)》 2016年 第17卷 第5期   页码 403-412 doi: 10.1631/FITEE.1600028

摘要: Non-negative matrix factorization (NMF) has been widely used in mixture analysis for hyperspectral remote sensing. When used for spectral unmixing analysis, however, it has two main shortcomings: (1) since the dimensionality of hyperspectral data is usually very large, NMF tends to suffer from large computational complexity for the popular multiplicative iteration rule; (2) NMF is sensitive to noise (outliers), and thus the corrupted data will make the results of NMF meaningless. Although principal component analysis (PCA) can be used to mitigate these two problems, the transformed data will contain negative numbers, hindering the direct use of the multiplicative iteration rule of NMF. In this paper, we analyze the impact of PCA on NMF, and find that multiplicative NMF can also be applicable to data after principal component transformation. Based on this conclusion, we present a method to perform NMF in the principal component space, named ‘principal component NMF’ (PCNMF). Experimental results show that PCNMF is both accurate and time-saving.

关键词: Non-negative matrix factorization (NMF)     Principal component analysis (PCA)     Endmember     Hyperspectral    

of cutting parameters in high-speed milling based on grey relational analysis coupled with principal component

Tao FU, Jibin ZHAO, Weijun LIU

《机械工程前沿(英文)》 2012年 第7卷 第4期   页码 445-452 doi: 10.1007/s11465-012-0338-z

摘要:

This paper investigates optimization problem of the cutting parameters in high-speed milling on NAK80 mold steel. An experiment based on the technology of Taguchi is performed. The objective is to establish a correlation among spindle speed, feed per tooth and depth of cut to the three directions of cutting force in the milling process. In this study, the optimum cutting parameters are obtained by the grey relational analysis. Moreover, the principal component analysis is applied to evaluate the weights so that their relative significance can be described properly and objectively. The results of experiments show that grey relational analysis coupled with principal component analysis can effectively acquire the optimal combination of cutting parameters and the proposed approach can be a useful tool to reduce the cutting force.

关键词: high-speed milling     grey relational analysis     principal component analysis     parameters optimization    

银行国际贸易结算系统构件化设计与实现

余金山,陈志强

《中国工程科学》 2004年 第6卷 第9期   页码 81-87

摘要:

国际贸易结算是银行业中一种必不可少的业务,占据着重要的地位,而且随着电子商务的发展,其重要性也越来越突出。但是,这一业务的计算机化相当困难。主要原因是:操作流程复杂;组合变化太多,对灵活性有很高要求;涉及面相当广,几乎涉及银行的每一个业务品种,是一个压缩版的银行系统。因此,开发这样的系统必须采用先进的而且较为合适的方法和技术。文章提出了以构建半成品构件系统为总体思想的开发方法;在设计和实现上,提出了以数据总线为统一接口,以菜单/功能图标为总控主体框架,以基本业务操作为基本组件,并能把基本组件包装裁剪成可在主体框架控制下运行的功能构件,这样构建的系统可按实际需要进行组装、剪裁、参数设定、重新包装或经少量改写而形成一个实际可运行的系统。并提供了与银行总系统集成的灵活接口,具备了向网上银行和分布系统发展的良好基础。

关键词: 银行     国际贸易结算系统     构件     半成品系统    

Failure mode investigation of fuel cell for vehicle application

Zhongjun HOU, Renfang WANG, Keyong WANG, Weiyu SHI, Danming XING, Hongchun JIANG

《能源前沿(英文)》 2017年 第11卷 第3期   页码 318-325 doi: 10.1007/s11708-017-0488-0

摘要: The durability of proton exchange membrane fuel cells (PEMFCs) has been posing a key technical challenge to commercial spread of fuel cell vehicles (FCVs). To improve the durability, it is necessary to optimize the fuel cell system (FCS) design against failure modes. The fuel cell durability research method at FCS scale was exhibited, and the failure modes of fuel cell were experimentally investigated in this paper. It is found that the fuel cell dry operation, start/stop cycle and gas diffusion layer (GDL) flooding are typical failure modes of fuel cells. After the modifications against the failure modes, the durability of FCSs is improved to over 3000 h step by step.

关键词: proton exchange membrane fuel cell (PEMFC)     fuel cell system (FCS)     durability     failure mode     fuel cell vehicle (FCV)     carbon corrosion     water management    

removal of ocular artifacts from electroencephalogram signals using spatial constraint independent component

Bang-hua YANG,Liang-fei HE,Lin LIN,Qian WANG

《信息与电子工程前沿(英文)》 2015年 第16卷 第6期   页码 486-496 doi: 10.1631/FITEE.1400299

摘要: Ocular artifacts cause the main interfering signals within electroencephalogram (EEG) signal measurements. An adaptive filter based on reference signals from an electrooculogram (EOG) can reduce ocular interference, but collecting EOG signals during a long-term EEG recording is inconvenient and uncomfortable for the subject. To remove ocular artifacts from EEG in brain-computer interfaces (BCIs), a method named spatial constraint independent component analysis based recursive least squares (SCICA-RLS) is proposed. The method consists of two stages. In the first stage, independent component analysis (ICA) is used to decompose multiple EEG channels into an equal number of independent components (ICs). Ocular ICs are identified by an automatic artifact detection method based on kurtosis. Then empirical mode decomposition (EMD) is employed to remove any cerebral activity from the identified ocular ICs to obtain exact artifact ICs. In the second stage, first, SCICA applies exact artifact ICs obtained in the first stage as a constraint to extract artifact ICs from the given EEG signal. These extracted ICs are called spatial constraint ICs (SC-ICs). Then the RLS based adaptive filter uses SC-ICs as reference signals to reduce interference, which avoids the need for parallel EOG recordings. In addition, the proposed method has the ability of fast computation as it is not necessary for SCICA to identify all ICs like ICA. Based on the EEG data recorded from seven subjects, the new approach can lead to average classification accuracies of 3.3% and 12.6% higher than those of the standard ICA and raw EEG, respectively. In addition, the proposed method has 83.5% and 83.8% reduction in time-consumption compared with the standard ICA and ICA-RLS, respectively, which demonstrates a better and faster OA reduction.

关键词: Ocular artifacts     Electroencephalogram (EEG)     Electrooculogram (EOG)     Brain-computer interface (BCI)     Spatial constraint independent component analysis based recursive least squares (SCICA-RLS)    

Numerical investigation of the effects of fuel spray type on the interaction of fuel spray and hot porous

ZHAO Zhiguo, XIE Maozhao

《能源前沿(英文)》 2008年 第2卷 第1期   页码 59-65 doi: 10.1007/s11708-008-0022-5

摘要: The interaction between two types of fuel spray and a hot porous medium is studied numerically by using an improved version of KIVA-3V code. The improved KIVA-3V code is incorporated with an impingement model, a heat transfer model and a linearized instability sheet atomization (LISA) model to model the hollow cone spray. An evaporating fuel spray impingement on a hot plane surface was simulated under conditions of experiments performed by Senda to validate the reasonability of the KIVA-3V code. The numerical results conform well with experimental data for spray radius in the liquid and the vapor phases. Computational results on the interaction of two types of the fuel spray and the hot porous medium show that the fuel spray can be split, which provides conditions for quick evaporation of fuel droplets and mixing of fuel vapor with air. The possibility of fuel droplets from hollow cone spray crossing the porous medium reduces compared with that from solid cone spray, with the same initial kinetic energy of fuel droplets in both injection types.

关键词: improved version     impingement     atomization     hollow     radius    

Recent advances in cathode electrocatalysts for PEM fuel cells

Junliang ZHANG

《能源前沿(英文)》 2011年 第5卷 第2期   页码 137-148 doi: 10.1007/s11708-011-0153-y

摘要: Great progress has been made in the past two decades in the development of the electrocatalysts for proton exchange membrane fuel cells (PEMFCs). This review article is focused on recent advances made in the kinetic-activity improvement on platinum- (Pt-) based cathode electrocatalysts for the oxygen reduction reaction (ORR). The origin of the limited ORR activity of Pt catalysts is discussed, followed by a review on the development of Pt alloy catalysts, Pt monolayer catalysts, and shape- and facet-controlled Pt-alloy nanocrystal catalysts. Mechanistic understanding is reviewed as well on the factors contributing to the enhanced ORR activity of these catalysts. Finally, future directions for PEMFC catalyst research are proposed.

关键词: proton exchange membrane fuel cells (PEMFCs)     cathode electrocatalysts     platinum     oxygen reduction reaction (ORR)    

标题 作者 时间 类型 操作

Application of spectral technology in flame measurement

Jiaxun LIU, Xiaoshu CAI, Zenghao ZHU, Huinan YANG

期刊论文

An exploratory study for predicting component reliability with new load conditions

Zhengwei HU, Xiaoping DU

期刊论文

Improved resilience measure for component recovery priority in power grids

期刊论文

Molecular level simulations on multi-component systems —a morphology prediction method

C. SCHMIDT, J. ULRICH

期刊论文

Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web component

Ke WEI, Xiaoguang FAN, Mei ZHAN, Miao MENG

期刊论文

Development of a multi-component drug from turmeric using central composite design

Xiaohang ZHANG,Shengnan HAN,Yan LI,Jianlan JIANG

期刊论文

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

期刊论文

Impacts of methanol fuel on vehicular emissions: A review

期刊论文

Non-negativematrix factorization based unmixing for principal component transformed hyperspectral data

Xiu-rui GENG,Lu-yan JI,Kang SUN

期刊论文

of cutting parameters in high-speed milling based on grey relational analysis coupled with principal component

Tao FU, Jibin ZHAO, Weijun LIU

期刊论文

银行国际贸易结算系统构件化设计与实现

余金山,陈志强

期刊论文

Failure mode investigation of fuel cell for vehicle application

Zhongjun HOU, Renfang WANG, Keyong WANG, Weiyu SHI, Danming XING, Hongchun JIANG

期刊论文

removal of ocular artifacts from electroencephalogram signals using spatial constraint independent component

Bang-hua YANG,Liang-fei HE,Lin LIN,Qian WANG

期刊论文

Numerical investigation of the effects of fuel spray type on the interaction of fuel spray and hot porous

ZHAO Zhiguo, XIE Maozhao

期刊论文

Recent advances in cathode electrocatalysts for PEM fuel cells

Junliang ZHANG

期刊论文