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Study of the features of outburst caused by rock cross-cut coal uncovering and the law of gas dilatation energy release

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International Journal of Mining Science and Technology 2015年第3期25卷 453-458页

作者： yu Baohai su Chengxiang Wang Deming State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology Faculty of Safety Engineering China University of Mining and Technology Key Laboratory of Gas and Fire Control for Coal Mines China University of Mining and TechnologyMinistry of Education

To study the law of gas dilatation energy release of rock cross-cut coal uncovering face, according to the analysis of the physical parameters distribution features of coal and rock mass in front of crosscut face,the equations of elastic potential of coal and gas dilatation energy theory were set up to process a contrast calculation of the sizes of two kinds of energy. The results show that gas dilatation energy is the uppermost energy source causing outburst occurrence. Furthermore, the mathematical model of spherical flow field gas dilatation energy release was established and MATLAB software was applied to make a numerical calculation analysis on the law of gas dilatation energy release. The results indicate that the gas dilatation energy is closely related to gas parameters and its energy index does reflect the possibility of coal seam outburst.

关键词： Rock cross-cut coal uncovering Gas dilatation energy Numerical calculation Coal and gas outburst

Free amino group-directed C(sp^(2))-H arylation ofα-amino-β-aryl esters by palladium catalysis

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Chinese Chemical Letters 2024年第2期35卷 358-360页

作者： yue Gao yu Du Weiping su State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China University of Chinese Academy of Sciences Beijing 100049China

Native amino-directed palladium-catalyzed C(sp^(3))-H activation/functionalization has been developed for modification ofα-amino acids and *** a palladium(Ⅱ)-catalyzed C(sp^(2))-H arylation ofα-amino-β-aryl esters has been disclosed,using the native amino as the directing group.A variety of chiralα-amino-β-aryl esters can be functionalized to give the corresponding ortho-substituted mono-and di-arylated products.

关键词： Native amino-directed Palladium catalyst C(sp^(2))-H arylation α-Amino-β-aryl ester Chiralα-amino acid

Synergistic Effect of Core/Shell‑Structured Composite Fibers:Efficient Recovery of Rare‑Earth Elements from Spent NdFeB Permanent Magnets

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Advanced Fiber Materials 2024年第6期6卷 1729-1745页

作者： Youngkyun Jung yun Lee su‑Jin Yoon jae‑Woo Choi Center for Water Cycle Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Department of Chemical and Biological Engineering Korea UniversitySeoul 02841Republic of Korea Department of Energy and Environment Technology KIST SchoolKorea University of Science and TechnologySeoul 02792Republic of Korea

NdFeB magnets are third-generation permanent magnets that are employed as indispensable components in various ***,rare-earth elements(REEs)such as Dy and Nd must be efficiently recovered from end-of-life magnets to enable resource circulation and reinforce unstable supply *** that end,this paper reports synergistically performing core/shell-structured composite fibers(CSCFs)containing sodium polyacrylate and nanoporous zeolitic imidazolate framework-8(NPZIF-8)nanocrystals as a readily recoverable adsorbent with an exceptional REE-adsorbing *** CSCF core forms an NPZIF-8 nanocrystal shell on the fiber surface as well as draws REEs using its dense sodium carboxylate groups into the NPZIF-8 nanocrystal lattice with high specific surface *** CSCFs exhibit significantly higher maximum adsorption capacities(468.60 and 435.13 mg·g-1)and kinetic rate constants(2.02 and 1.92 min-1)for the Nd3+and Dy3+REEs than those of previously reported REE ***,the simple application of the CSCFs to an adsorption reactor considerably mitigates the adsorbent-shape-induced pressure drop,thereby directly influencing the energy efficiency of the ***,the high REE-recovery ability,tractability,and recyclability of the CSCFs offers a pragmatic pathway to achieving cost-effective REE ***,this study provides new insights into designing synergistically performing core/shell architectures for feasible REE recovery.

关键词： Core/shell structures Fibrous adsorbents Synergistic adsorption Metal resource recovery Pressure drop Rare-earth elements

Isothermal Crystallization of iPP in Environment-friendly Diluents:Effect of Binary Diluents and Crystallization Temperature on Crystallization Kinetics

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Chinese Journal of Polymer Science 2019年第6期37卷 617-626页

作者： yu-Jie Wang su-Ying Yan Zhi-Ping Zhao Zhen-yu Xi School of Chemistry and Chemical Engineering Beijing Institute of Technology Environmental Protection Research Institute Beijing Research Institute of Chemical IndustrySINOPEC

The growing demand for non-toxic solvents for membrane preparation has motivated the studies for green and sustainable alternatives of solvents. The effect of droplet isothermal growth within the liquid-liquid phase separation region on isothermal spherulitic growth rate of isotactic polypropylene(iPP) was investigated. The results showed that the droplets grew up at a rate of 0.0172 μm·s^(-1). The larger droplets slowed down the isothermal spherulitic growth rate of iPP. Higher mass ratio of carnauba wax(Cwax)/soybean oil(SO)resulted in faster droplet growth due to weak interaction with polymers. The isothermal crystallization behaviors of iPP in environmentfriendly binary diluents consisting of Cwax and SO mixture were further investigated experimentally using polarized optical *** was demonstrated that the isothermal spherulitic growth rate of iPP in diluents decreased nonlinearly with the increasing crystallization temperature. Compared with virgin iPP, isothermal spherulitic growth rate of iPP in SO diluent was significantly slowed down. The spherulitic growth was further retarded after the addition of Cwax in mixed diluents, resulting in a lower crystallization rate than that in SO. Moreover, the crystal form of iPP membranes was found to be α type through the characterization of small angle X-ray scattering and wide angle X-ray diffraction.

关键词： Isotactic polypropylene Carnauba wax Isothermal crystallization kinetics PP membrane

Simultaneous emission of orthogonal handedness in circular polarization from a single luminophore

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Light(Science & Applications) 2019年第1期8卷 39-46页

作者： Kyungmin Baek Dong-Myung Lee yu-Jin Lee Hyunchul Choi Jeongdae Seo Inbyeong Kang Chang-jae yu jae-Hoon Kim Department of Electronic Engineering Hanyang University222 WangsimniroSeongdong-guSeoul 04763Republic of Korea LG Display Co. Ltd.LG Science Park30 Magokjungang 10-roGangseo-guSeoul 07796Republic of Korea

The direct emission of circularly polarized(CP)light improves the efficiency of an organic light-emitting diode and characterizes the secondary structure of *** most cases,CP light is generated from a luminescent layer containing chiral characteristics,thereby generating only one kind of CP light in an entire ***,we propose direct CP light emissions using a twisted achiral conjugate polymer without any chiral dopant as an emitting layer(EML).The twisted structure is induced in the mesogenic conjugate polymer due to its elasticity by applying different alignment directions to its upper and lower ***,we demonstrate the simultaneous emission of orthogonal CP light in a single luminescent device by patterning different alignment directions on the surfaces of the *** light source with multipolarization including the orthogonal CP states is applicable to many applications in biosensors and optical devices.

关键词： circular twisted chiral

Effect of a seasonal diffuse pollution migration on natural organic matter behavior in a stratified dam reservoir

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Journal of Environmental Sciences 2010年第6期22卷 908-914页

作者： Soon Ju yu jae Yil Lee sung Ryong Ha National Institute of Environmental Research Department of Urban Engineering Chungbuk National University

This article aims to describe the influence of diffuse pollution on the temporal and spatial characteristics of natural organic matter （NOM） in a stratified dam reservoir, the Daecheong Dam, on the basis of intensive observation results and the dynamic water quality simulation using CE-QUAL-W2. Turbidity is regarded as a comprehensive representation of allochothonous organic matter from diffuse sources in storm season because the turbidity concentration showed reasonable significance in a statistical correlation with the UV absorbance at 254 nm and total phosphorus. CE-QUAL-W2 simulation results showed good consistency with the observed data in terms of dissolved organic matter （DOM） including refractory dissolved organic carbon （RDOC） and labile DOC and also well explained the internal movement of constituents and stratification phenomenon in the reservoir. Instead turbidity and NOM were related well in the upper region of the reservoir according to flow distance, gradually as changing to dissolved form of organic matter, RDOM affected organic matter concentration of reservoir water quality compared to turbidity. To control the increase of soluble organic matters in the dam reservoir, appropriate dam water discharge gate operation provided effective measurement. Because of the gate operation let avoid the accumulation of organic matter within a dam reservoir by shorten of turbid regime retention time.

关键词： CE-QUQL-W2 natural organic matter stratified dam reservoir turbidity flow

Integral sliding mode control of time-delay systems with mismatching uncertainties

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Journal of Systems Engineering and Electronics 2010年第2期21卷 273-280页

作者： Fu Zhao yu Liu Xiuming Yao Baoku su Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin 150001 R R. China

A linear matrix inequality （LMI）-based sliding surface design method for integral sliding mode control of uncertain time- delay systems with mismatching uncertainties is proposed. The uncertain time-delay system under consideration may have mis- matching norm bounded uncertainties in the state matrix as well as the input matrix, A sufficient condition for the existence of a sliding surface is given to guarantee asymptotic stability of the full order slJdJng mode dynamics. An LMI characterization of the slid- ing surface is given, together with an integral sliding mode control law guaranteeing the existence of a sliding mode from the initial time. Finally, a simulation is given to show the effectiveness of the proposed method.

关键词： linear matrix inequality integral sliding mode control uncertain time-delay systems mismatching uncertainties.

Exploring the potential of constructing a hybrid supercapacitor with FeCoNi-LDH porous material containing oxygen vacancies for high-performance energy storage applications

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Nano Research 2024年第9期17卷 8134-8144页

作者： Jihao su Ling Yang Dengbin yu Shaojun Dong State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China College of Chemistry Jilin UniversityChangchun 130022China University of Science and Technology of China Hefei 230026China

A significant challenge in developing high-performance hybrid supercapacitors(HSCs)is the need to reasonably construct advanced architectures that consist of various components and exhibit superior electrochemical capacitance *** FeCoNi-layered double hydroxide(FeCoNi-LDH)porous material has a specific capacitance of 1960 F·g^(-1)when used as the anode material at 1 A·g^(-1).The FeCoNi-LDH material exhibits nanoplates with a distinct spindle morphology on their *** to the combined action of the three metals and abundant oxygen vacancies,they exhibit unique rate performance and cycle *** electronic structure of LDH and the regulation of oxygen vacancy were confirmed by density functional theory(DFT)*** suggests that the strength of hydroxide can reduce the energy required for oxygen vacancy formation in FeCoNi-LDH nanosheets and enhance ion and charge transfer,as well as electrolyte adsorption on the electrode *** FeCoNi-LDH//activated carbon(AC)HSC has an energy density of 53.2 Wh·kg^(-1)at a power density of 800 W·kg^(-1),surpassing other devices composed of comparable materials during the same *** study made significant advances in the design and synthesis of a ternary LDH porous structure with distinct oxygen vacancies,as well as its potential application in electrochemical energy storage.

关键词： oxygen vacancy FeCoNi-layered double hydroxide(FeCoNi-LDH) theory calculation electrode material hybrid supercapacitor

Effect of air bubble size on cavitation erosion reduction

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Science China(Technological Sciences) 2017年第4期60卷 523-528页

作者： WU JianHua su KunPeng WANG yu GOU WenJuan College of Water Conservancy and Hydropower Engineering Hohai University State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University

Over the past 60 years, the air concentration in water has been considered as a control index of cavitation erosion reduction and widely used in the designs of hydraulic structures. However, the mechanism of air entrainment against cavitation erosion has been paid good attention to. In the present work, the effect of air bubble size on cavitation erosion reduction was experimentally investigated. A device with micron-scale orifice diameters(10, 20 and 50 μm in size) was specially designed to introduce air bubbles into water. The experiments about the effect of air bubble size were conducted by means of a vibratory apparatus, including the behavior of formation and movement for single air bubble, the characteristics of cavitation erosion reduction at different air entrainment conditions. The findings demonstrate that high air concentration has significant effects on cavitation erosion ***, a notable problem was that the size of air bubbles is of outstanding effect on cavitation erosion reduction. Small air bubbles support to alleviate cavitation erosion, even at same air concentration.

关键词： air bubble size air entrainment cavitation erosion micron-scale