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Preconcentration of trace elements by adsorption onto a niobium wire for electrothermal atomization atomicabsorption spectrometry with a tungsten tube atomizer

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 432-435 doi: 10.1007/s11705-012-1219-z

摘要： In the present work, a new preconcentration method of trace elements by adsorption onto a niobium wire has been developed for electrothermal atomization atomic absorption spectrometry (ETAAS) with a tungsten tube atomizer. Detection limits (pg·mL ) by this method combined with ETAAS were 45 for bismuth, 7.0 for cadmium, 20 for copper, 1.3 for gold, 36 for lead, 65 for manganese, 9.5 for rhodium and 19 for silver.

关键词： preconcentration     adsorption onto niobium wire     electrothermal atomization atomic absorption spectrometry     tungsten tube atomizer     trace elements    

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Ultrasound-assisted emulsification solidified floating organic drop microextraction for the determination of trace amounts of copper in water samples

Qingyun CHANG, Jingwen ZHANG, Xin DU, Jingjun MA, Jingci LI,

《环境科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 187-195 doi: 10.1007/s11783-010-0030-7

摘要： A simple and efficient liquid-phase microextraction (LPME) technique was developed using ultrasound-assisted emulsification solidified floating organic drop microextraction (USAE-SFODME) combined with flame atomic absorption spectrometry, for the extraction and determination of trace copper in water samples. 1-(2-Pyridylazo)-2-naphthol (PAN) was used as chelating agent. Microextraction efficiency factors (including extraction solvent type, extraction volume, time, temperature, and pH), the amount of the chelating agent, and salt effect were investigated and optimized. Under the optimum extraction conditions, figures of merit of the proposed method were evaluated. The calibration graph was linear in the range of 20–600 g·L with a detection limit of 0.76 g·L. The relative standard deviation (R.S.D) for ten replicate measurements of 20 and 400 g·L of copper was 3.83% and 2.65%, respectively. Finally, the proposed method was applied to tap water, river water, and sea water, and accuracy was assessed through the analysis of certified reference water or recovery experiments.

关键词： ultrasound-assisted emulsification     solidified floating organic drop microextraction     flame atomic absorption spectrometry     preconcentration     copper    

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A magnetic adsorbent based on salicylic acid-immobilized magnetite nano-particles for pre-concentration of Cd(II) ions

Hossein Abdolmohammad-Zadeh, Arezu Salimi

《化学科学与工程前沿（英文）》 2021年 第15卷 第2期   页码 450-459 doi: 10.1007/s11705-020-1930-0

摘要： In this research, an eco-friendly magnetic adsorbent based on Fe O /salicylic acid nanocomposite was fabricated using a facile one-pot co-precipitation method. The crystalline and morphological characterization of the prepared nanocomposite was performed by field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The nanocomposite was employed as a magnetic solid-phase extraction agent for separation of Cd(II) ions from synthetic solutions. Some experimental factors affecting the extraction efficiency were investigated and optimized. Following elution with acetic acid (pH 3.5), the pre-concentrated analyte was quantified by flame atomic absorption spectrometry. In optimal conditions, a linear calibration graph was achieved in the concentration range of 0.2‒30 ng·mL with a determination coefficient ( ) of 0.9953. The detection limit, the enhancement factor, inter- and intra-day relative standard deviations (for six consecutive extractions at the concentration level of 10 ng·mL ) were 0.04 ng·mL , 100, 2.38% and 1.52%, respectively. To evaluate the accuracy of the method, a certified reference material (NIST SRM 1643e) was analyzed, and there was a good agreement between the certified and the measured values. It was successfully utilized to determine cadmium in industrial wastewater samples and the attained relative recovery values were between 96.8% and 103.2%.

关键词： cadmium     magnetic solid-phase extraction     Fe3O4 nanoparticles     Fe3O4/salicylic acid nanocomposite     flame atomic absorption spectrometry    

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Applications of atomic force microscopy in immunology

Jiping Li, Yuying Liu, Yidong Yuan, Bo Huang

《医学前沿（英文）》 2021年 第15卷 第1期   页码 43-52 doi: 10.1007/s11684-020-0769-6

摘要： Cellular mechanics, a major regulating factor of cellular architecture and biological functions, responds to intrinsic stresses and extrinsic forces exerted by other cells and the extracellular matrix in the microenvironment. Cellular mechanics also acts as a fundamental mediator in complicated immune responses, such as cell migration, immune cell activation, and pathogen clearance. The principle of atomic force microscopy (AFM) and its three running modes are introduced for the mechanical characterization of living cells. The peak force tapping mode provides the most delicate and desirable virtues to collect high-resolution images of morphology and force curves. For a concrete description of AFM capabilities, three AFM applications are discussed. These applications include the dynamic progress of a neutrophil-extracellular-trap release by neutrophils, the immunological functions of macrophages, and the membrane pore formation mediated by perforin, streptolysin O, gasdermin D, or membrane attack complex.

关键词： cellular mechanics     atomic force microscopy     neutrophil extracellular trap     macrophage phagocytosis     pore formation    

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Transient process of methane-oxygen diffusion flame-street establishment in a microchannel

《能源前沿（英文）》 2022年 第16卷 第6期   页码 988-999 doi: 10.1007/s11708-021-0755-y

摘要： “Flame-street” is an interesting diffusion flame behavior in which a series of flame-segments is separately distributed along the mixing layer in a narrow channel. This experimental phenomenon was experimentally and numerically investigated with the focus on the steady-state, thermo-chemical flame structures in previous literature. In the present paper, the dynamic formation process of a methane-oxygen diffusion flame-street structure was simulated with a reacting flow solver developed based on the open-source framework OpenFOAM. By imposing a certain amount of ignition-energy near the channel outlet, a reaction-kernel was formed and bifurcated. Subsequently, three separate flames were consecutively generated from this kernel and propagated within the channel. The whole process was completed within 15 ms and all the discrete flames were eventually in a steady-state. Interestingly, different propagation features were observed for the three flame segments: The leading flame experienced a flame shape/type change from a tribrachial structure in its fast-propagating phase to a long, trailing diffusion tail after being anchored to the inlet. The successive flame had a much lower propagation speed, keeping its two wing-like (fuel-lean premixed and fuel-rich premixed) structure while moving toward its stabilization location, which was approximately in the middle of the channel. The last flame, after the ignition source was turned-off, was immediately convected a bit downstream, and eventually featured a similar two-branch-like structure as the second one. Moreover, chemical insights for the premixed and diffusion branches of the leading flame were also provided with the change of significance of some key elementary reactions focused on, in order to attain a detailed profiling of the flame-type transition. This paper is a first-ever one discussing the transient formation of flame-streets in literature and is believed to be useful for obtaining a comprehensive understanding of this unique flame characteristics from a dynamic point of view.

关键词： micro-combustion     flame-street     diffusion flame     mixing layer     flame propagation speed    

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Atomic and close-to-atomic scale manufacturing—A trend in manufacturing development

Fengzhou FANG

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 325-327 doi: 10.1007/s11465-016-0402-1

摘要：

Manufacturing is the foundation of a nation’s economy. It is the primary industry to promote economic and social development. To accelerate and upgrade China’s manufacturing sector from “precision manufacturing” to “high-performance and high-quality manufacturing”, a new breakthrough should be found in terms of achieving a “leap-frog development”. Unlike conventional manufacturing, the fundamental theory of “Manufacturing 3.0” is beyond the scope of conventional theory; rather, it is based on new principles and theories at the atomic and/or close-to-atomic scale. Obtaining a dominant role at the international level is a strategic move for China’s progress.

关键词： atomic manufacturing     Manufacturing 3.0     Manufacturing 2025     Industry 4.0    

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NC flame pipe cutting machine tool based on open architecture CNC system

Xiaogen NIE, Yanbing LIU

《机械工程前沿（英文）》 2009年 第4卷 第2期   页码 147-152 doi: 10.1007/s11465-009-0025-x

摘要： Based on the analysis of the principle and flame movement of a pipe cutting machine tool, a retrofit NC flame pipe cutting machine tool (NFPCM) that can meet the demands of cutting various pipes is proposed. The paper deals with the design and implementation of an open architecture CNC system for the NFPCM, many of whose aspects are similar to milling machines; however, different from their machining processes and control strategies. The paper emphasizes on the NC system structure and the method for directly creating the NC file according to the cutting type and parameters. Further, the paper develops the program and sets up the open and module NC system.

关键词： flame pipe cutting     flame incision tracks     CNC     open architecture CNC system    

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Experimental study on the laminar flame speed of hydrogen/natural gas/air mixtures

Chen DONG, Qulan ZHOU, Xiaoguang ZHANG, Qinxin ZHAO, Tongmo XU, Shi’en HUI

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 417-422 doi: 10.1007/s11705-010-0515-8

摘要： Laminar flame speeds of hydrogen/natural gas/air mixtures have been measured over a full range of fuel compositions (0–100% volumetric fraction of H ) and a wide range of equivalence ratio using Bunsen burner. High sensitivity scientific CCD camera is use to capture the image of laminar flame. The reaction zone area is employed to calculate the laminar flame speed. The initial temperature and pressure of fuel air mixtures are 293 K and 1 atm. The laminar flame speeds of hydrogen/air mixture and natural gas/air mixture reach their maximum values 2.933 and 0.374 m/s when equivalence ratios equal to 1.7 and 1.1, respectively. The laminar flame speeds of hydrogen/natural gas/air mixtures rise with the increase of volumetric fraction of hydrogen. Moreover, the increase in laminar flame speed as the volumetric fraction of hydrogen increases presents an exponential increasing trend versus volumetric fraction of hydrogen. Empirical formulas to calculate the laminar flame speeds of hydrogen, natural gas, and hydrogen/natural gas mixtures are also given. Using these formulas, the laminar flame speed at different hydrogen fractions and equivalence ratios can be calculated.

关键词： laminar flame speed     experimental study     Bunsen flame    

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Experimental and kinetic study on laminar flame speeds of ammonia/syngas/air at a high temperature and

《能源前沿（英文）》 2022年 第16卷 第2期   页码 263-276 doi: 10.1007/s11708-021-0791-7

摘要： The laminar flame speeds of ammonia mixed with syngas at a high pressure, temperature, and different syngas ratios were measured. The data obtained were fitted at different pressures, temperatures, syngas ratios, and equivalence ratios. Four kinetic models (the Glarborg model, Shrestha model, Mei model, and Han model) were compared and validated with experimental data. Pathway, sensitivity and radical pool analysis are conducted to find out the deep kinetic insight on ammonia oxidation and NO formation. The pathway analysis shows that H abstraction reactions and NHi combination reactions play important roles in ammonia oxidation. NO formation is closely related to H, OH, the O radical produced, and formation reactions. NO is mainly formed from reaction, HNO+ H= NO+ H2. Furthermore, both ammonia oxidation and NO formation are sensitive to small radical reactions and ammonia related reactions.

关键词： ammonia mixed with syngas     laminar flame speed     kinetic model     sensitivity analysis     pathway analysis    

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Molybdenum disulfide@nickel phyllosilicate hybrid for improving the flame retardancy and wear resistance

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2114-2126 doi: 10.1007/s11705-023-2357-1

摘要： In this study, nickel phyllosilicate was synthesized based on molybdenum disulfide (MoS2@NiPS) by the sol-gel method, and then MoS2@NiPS was used to prepare epoxy composites. The thermal stability, flame retardancy, and frictional performances of epoxy composites were studied. With the addition of 3 wt% MoS2@NiPS, the epoxy composite increased the limiting oxygen index from 23.8% to 26.1% and reduced the vertical burning time from 166 s for epoxy resin to 35 s. The residual char of the epoxy composite increased from 11.8 to 20.2 wt%. MoS2@NiPS promoted the graphitization of the residual char, and facilitated the formation of a dense and continuous char layer, thereby improving the fire safety of epoxy resin. The epoxy composite with 3 wt% MoS2@NiPS had excellent wear resistance property with a wear rate of 2.19 × 10−5 mm3·N–1·m–1, which was 68.8% lower than that of epoxy resin. This study presented a practical approach to improve the frictional and fire resistance of epoxy composites.

关键词： molybdenum disulfide     nickel phyllosilicate     epoxy resin     flame retardancy    

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A low-density polyethylene composite with phosphorus-nitrogen based flame retardant and multi-walledcarbon nanotubes for enhanced electrical conductivity and acceptable flame retardancy

Yong Luo, Yuhui Xie, Renjie Chen, Ruizhi Zheng, Hua Wu, Xinxin Sheng, Delong Xie, Yi Mei

《化学科学与工程前沿（英文）》 2021年 第15卷 第5期   页码 1332-1345 doi: 10.1007/s11705-021-2035-0

摘要： Design and exploitation of flame retardant polymers with high electrical conductivity are desired for polymer applications in electronics. Herein, a novel phosphorus-nitrogen intumescent flame retardant was synthesized from pentaerythritol octahydrogen tetraphosphate, phenylphosphonyl dichloride, and aniline. Low-density polyethylene was combined with the flame retardant and multi-walled carbon nanotubes to form a nanocomposite material via a ball-milling and hot-pressing method. The electrical conductivity, mechanical properties, thermal performance, and flame retardancy of the composites were investigated using a four-point probe instrument, universal tensile machine, thermogravimetric analysis, and cone calorimeter tests, respectively. It was found that the addition of multi-walled carbon nanotubes can significantly improve the electrical conductivity and mechanical properties of the low-density polyethylene composites. Furthermore, the combination of multi-walled carbon nanotubes and phosphorus–nitrogen flame retardant remarkably enhances the flame retardancy of matrixes with an observed decrease of the peak heat release rate and total heat release of 49.8% and 51.9%, respectively. This study provides a new and effective methodology to substantially enhance the electrical conductivity and flame retardancy of polymers with an attractive prospect for polymer applications in electrical equipment.

关键词： MWCNTs     PEPA     electrical conductivity     flame retardant     low density polyethylene    

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A method of determining flame radiation fraction induced by interaction burning of tri-symmetric propane

Jie JI, Junrui DUAN, Huaxian WAN

《能源前沿（英文）》 2022年 第16卷 第6期   页码 1017-1026 doi: 10.1007/s11708-020-0716-x

摘要： The interaction of multiple fires may lead to a higher flame height and more intense radiation flux than a single fire, which increases the possibility of flame spread and risks to the surroundings. Experiments were conducted using three burners with identical heat release rates (HRRs) and propane as the fuel at various spacings. The results show that flames change from non-merging to merging as the spacing decreases, which result in a complex evolution of flame height and merging point height. To facilitate the analysis, a novel merging criterion based on the dimensionless spacing / was proposed. For non-merging flames ( / >0.368), the flame height is almost identical to a single fire; for merging flames ( / ≤0.368), based on the relationship between thermal buoyancy and thrust (the pressure difference between the inside and outside of the flame), a quantitative analysis of the flame height, merging point height, and air entrainment was formed, and the calculated merging flame heights show a good agreement with the measured experimental values. Moreover, the multi-point source model was further improved, and radiation fraction of propane was calculated. The data obtained in this study would play an important role in calculating the external radiation of propane fire.

关键词： flame interaction     air entrainment     flame height     multi-point source model     thermal radiation    

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Flame-retardant properties of

Kumar Sai SMARAN, Rajashekar BADAM, Raman VEDARAJAN, Noriyoshi MATSUMI

《能源前沿（英文）》 2019年 第13卷 第1期   页码 163-171 doi: 10.1007/s11708-018-0554-2

摘要： This paper focuses on the superiority of organic-inorganic hybrid ion-gel electrolytes for lithium-ion batteries (LiBs) over commercial electrolytes, such as 1 M LiPF in 1:1 ethylene carbonate (EC): dimethyl carbonate (DMC) {1 M LiPF -EC: DMC}, in terms of their flame susceptibility. These ion-gel electrolytes possess ionic liquid monomers, which are confined within the borosilicate or silicate matrices that are ideal for non-flammability. Naked flame tests confirm that the organic-inorganic hybrid electrolytes are less susceptible to flames, and these electrolytes do not suffer from a major loss in terms of weight. In addition, the hybrids are self-extinguishable. Therefore, these hybrids are only oxidized when subjected to a flame unlike other commercial electrolytes used in lithium-ion batteries. Supplementary analyses using differential scanning calorimetric studies reveal that the hybrids are glassy until the temperature reaches more than 100°C. The current results are consistent with previously published data on the organic-inorganic hybrids.

关键词： inorganic polymeric borosilicate network     organic-inorganic hybrids     self-extinguishability     nonflammability     lithium batteries     flame-retardants    

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Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

《机械工程前沿（英文）》 2020年 第15卷 第4期   页码 631-644 doi: 10.1007/s11465-020-0599-x

摘要： The ever-increasing requirements for the scalable manufacturing of atomic-scale devices emphasize the significance of developing atomic-scale manufacturing technology. The mechanism of a single atomic layer removal in cutting is the key basic theoretical foundation for atomic-scale mechanical cutting. Material anisotropy is among the key decisive factors that could not be neglected in cutting at such a scale. In the present study, the crystallographic orientation effect on the cutting-based single atomic layer removal of monocrystalline copper is investigated by molecular dynamics simulation. When undeformed chip thickness is in the atomic scale, two kinds of single atomic layer removal mechanisms exist in cutting-based single atomic layer removal, namely, dislocation motion and extrusion, due to the differing atomic structures on different crystallographic planes. On close-packed crystallographic plane, the material removal is dominated by the shear stress-driven dislocation motion, whereas on non-close packed crystallographic planes, extrusion-dominated material removal dominates. To obtain an atomic, defect-free processed surface, the cutting needs to be conducted on the close-packed crystallographic planes of monocrystalline copper.

关键词： ACSM     single atomic layer removal mechanism     crystallographic orientation effect     mechanical cutting     Manufacturing III    

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Recent progress in electric-field assisted combustion: a brief review

《能源前沿（英文）》 2022年 第16卷 第6期   页码 883-899 doi: 10.1007/s11708-021-0770-z

摘要： The control of combustion is a hot and classical topic. Among the combustion technologies, electric-field assisted combustion is an advanced techno-logy that enjoys major advantages such as fast response and low power consumption compared with thermal power. However, its fundamental principle and impacts on the flames are complicated due to the coupling between physics, chemistry, and electromagnetics. In the last two decades, tremendous efforts have been made to understand electric-field assisted combustion. New observations have been reported based on different combustion systems and improved diagnostics. The main impacts, including flame stabilization, emission reduction, and flame propagation, have been revealed by both simulative and experimental studies. These findings significantly facilitate the application of electric-field assisted combustion. This brief review is intended to provide a comprehensive overview of the recent progress of this combustion technology and further point out research opportunities worth investigation.

关键词： electric field     combustion     flame stabilization     emission reduction     flame propagation    

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标题 作者 时间 类型 操作

Preconcentration of trace elements by adsorption onto a niobium wire for electrothermal atomization atomicabsorption spectrometry with a tungsten tube atomizer

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

期刊论文

Ultrasound-assisted emulsification solidified floating organic drop microextraction for the determination of trace amounts of copper in water samples

Qingyun CHANG, Jingwen ZHANG, Xin DU, Jingjun MA, Jingci LI,

期刊论文

A magnetic adsorbent based on salicylic acid-immobilized magnetite nano-particles for pre-concentration of Cd(II) ions

Hossein Abdolmohammad-Zadeh, Arezu Salimi

期刊论文

Applications of atomic force microscopy in immunology

Jiping Li, Yuying Liu, Yidong Yuan, Bo Huang

期刊论文

Transient process of methane-oxygen diffusion flame-street establishment in a microchannel

期刊论文

Atomic and close-to-atomic scale manufacturing—A trend in manufacturing development

Fengzhou FANG

期刊论文

NC flame pipe cutting machine tool based on open architecture CNC system

Xiaogen NIE, Yanbing LIU

期刊论文

Experimental study on the laminar flame speed of hydrogen/natural gas/air mixtures

Chen DONG, Qulan ZHOU, Xiaoguang ZHANG, Qinxin ZHAO, Tongmo XU, Shi’en HUI

期刊论文

Experimental and kinetic study on laminar flame speeds of ammonia/syngas/air at a high temperature and

期刊论文

Molybdenum disulfide@nickel phyllosilicate hybrid for improving the flame retardancy and wear resistance

期刊论文

A low-density polyethylene composite with phosphorus-nitrogen based flame retardant and multi-walledcarbon nanotubes for enhanced electrical conductivity and acceptable flame retardancy

Yong Luo, Yuhui Xie, Renjie Chen, Ruizhi Zheng, Hua Wu, Xinxin Sheng, Delong Xie, Yi Mei

期刊论文

A method of determining flame radiation fraction induced by interaction burning of tri-symmetric propane

Jie JI, Junrui DUAN, Huaxian WAN

期刊论文

Flame-retardant properties of

Kumar Sai SMARAN, Rajashekar BADAM, Raman VEDARAJAN, Noriyoshi MATSUMI

期刊论文

Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

期刊论文

Recent progress in electric-field assisted combustion: a brief review

期刊论文