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Low cost, high performance supercapacitor electrode using coconut wastes: eco-friendly approach

Journal of Energy Chemistry 2016年第5期25卷 880-887页

作者： Divyashree A. shoriya arun. bt abdul man.f Yallappa S. Chaitra K. Kathyayini N. Gurumurthy Hegde BMS R and D Centre BMS College of Engineering faculty of Industrial Sciences and Technology Universiti Malaysia Pahang Jain University Jain Global Campus Jakkasandra Post

Low cost, high performance supercapacitor electrodes were fabricated using coconut waste as precursor. Simple one step pyrolysis is adopted to get the spherical shaped particle where lignocellulosic nature of carbon converts into porous carbon nanospheres. Three types of coconut wastes, namely, coconut fiber(Cf), coconut leaves(CL) and coconut stick(CS) have been studied and compared for their application in supercapacitors. Uniform spherical shape with particle size ranging from 30 to 60 nm for leaves and sticks and20 nm for fibers was obtained. The electrochemical properties of the porous carbon nanospheres were studied using cyclic voltammetry(CV), chronopotentiometry(CP) and electrochemical impedance spectroscopy(EIS). The porous carbon nanospheres derived from all the three biowaste samples show good electrochemical performance for supercapacitor application. Porous carbon nanospheres derived from coconut fiber exhibited maximum specific capacitance of 236 f/g followed by coconut stick and coconut leaves with 208 and 116 f/g respectively at a scan rate of 2 m V/s. further impedance studies showed a charge transfer resistance of 4.9 for the porous carbon nanospheres derived from coconut fiber, while those from coconut leaves and coconut stick exhibited a slightly higher resistance of 6 and14.2, respectively. The simple eco-friendly approach we have demonstrated for synthesizing coconut waste based carbon nanospheres makes them excellent candidates for future, low-cost, energy storage devices.

关键词： Low cost Coconut waste Biowaste High performance Supercapacitor Energy storage

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Superior supercapacitive performance in porous nanocarbons

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Journal of Energy Chemistry 2016年第4期25卷 734-739页

作者： Gomaa A.M.Ali shoriya arun. abdul man.f Divyashree A Kwok feng Chong Gurumurthy Hegde Chemistry Department Faculty of ScienceAl-Azhar University faculty of Industrial Sciences and Technology Universiti Malaysia Pahang BMS R and D Centre BMS College of Engineering

Porous nanocarbons with average particle size 20–40 nm were developed using biowaste oil palm leaves as a *** pyrolysis was carried out at 700 °C under nitrogen *** porous nanocarbons showed excellent porous nature along with spherical *** supercapacitor fabricated from porous nanocarbons showed superior supercapacitance performance where high specific capacitance of 368 f/g at 0.06 A/g in 5 M KOH were *** also exhibited high stability(96% over 1700cycles) and energy density of 13 Wh/*** resistance values were obtained by fitting the impedance spectra,thus indicating the availability of these materials as supercapacitors *** presented method is cost effective and also in line with waste to wealth approach.

关键词： Porous carbon nanoparticles Supercapacitor Catalyst free Biowaste

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Nature of Surface Layer and Electrochemical Behavior of NaOH Hydrothermally Treated NiTi Alloy

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Journal of Materials Science & Technology 2004年第2期20卷 185-188页

作者： P.Shi f.T.Cheng H.C.man DepartmentofAppliedPhysics TheHongKongPolytechnicUniversityHongKongChina DepartmentofIndustrialandSystemsEngineering TheHongKongPolytechnicUniversityHongKongChina

NiTi samples were hydrothermally treated in NaOH at 200℃ with different soaking times. The morphology of the surface layer formed was studied by scanning electron microscopy (SEM). The composition of the layer and the major phases present were determined by energy-dispersive spectroscopy (EDS) and X-ray diffractometry (XRD), respectively. In contrast to the results reported by some authors, the surface layer was essentially Ni(OH)2 instead of being TiO2. The electrochemical behavior of the samples was studied by electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution at 23℃, and analyzed using a simplified Randle circuit consisting of a resistance R and a capacitance C in parallel. After hydrothermal treatment, R was increased by a factor ranging from 1.5 to 5.0 times, depending on the treatment time. The value of R of all the samples became steady within a period of less than 15 h. Results of the present study indicate that alkaline treatment leads to the growth of an insulating layer on NiTi, but the method is not suitable for surface modification of NiTi implants due to the enhanced Ni content in the surface layer.

关键词： Hydrothermal treatment NiTi NaOH Resistance Electrochemical impedance spectroscopy

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Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第01期 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-fei Xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe f and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe f/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

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Solution and Analysis of the fuzzy Volterra Integral Equations viaHomotopy Analysis Method

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Computer Modeling in Engineering & Sciences 2021年第6期127卷 875-899页

作者： Ali.f.Jameel N.R.Anakira A.K.Alomari Noraziah H.man School of Quantitative Sciences Universiti Utara MalaysiaKedahSintok06010Malaysia Department of Mathematics Faculty of Science and TechnologyIrbid National UniversityIrbid2600Jordan Department of Mathematics Faculty of ScienceYarmouk UniversityIrbid21163Jordan

Homotopy Analysis Method(HAM)is semi-analytic method to solve the linear and nonlinear mathematical models which can be used to obtain the approximate *** HAM includes an auxiliary parameter,which is an efficient way to examine and analyze the accuracy of linear and nonlinear *** main aim of this work is to explore the approximate solutions of fuzzy Volterra integral equations(both linear and nonlinear)with a separable kernel via *** method provides a reliable way to ensure the convergence of the approximation series.A new general form of HAM is presented and analyzed in the fuzzy domain.A qualitative convergence analysis based on the graphical method of a fuzzy HAM is *** solutions sought by the proposed method show that the HAM is easy to implement and computationally quite *** solutions of fuzzy second kind Volterra integral equations are solved as numerical examples to show the potential of the *** results also show that HAM provides an easy way to control and modify the convergence area in order to obtain accurate solutions.

关键词： Homotopy analysis method convergence control parameter fuzzy Volterra integral equations

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Responses of soil nitrogen, phosphorous and organic matter to vegetation succession on the Loess Plateau of China

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Journal of Arid Land 2015年第2期7卷 216-223页

作者： man CHENG Shao Shan AN College of Natural Resources and Environment Northwest A&F University State Key Laboratory of Soil Erosion and Dryland farming on the Loess Plateau Northwest A&F University

Revegetation is a traditional practice widely used for soil protection. We evaluated the effect of natural revegetation succession on soil chemical properties and carbon fractions （particulate organic carbon （POC）, humus carbon （HS-C）, humic acid carbon （HA-C） and fulvic acid carbon （fA-C）） on the Loess Plateau of China. The vegetation types, in order from the shortest to the longest enclosure duration, were：（a） abandoned overgrazed grassland （AbG3; 3 years）; （b） Hierochloe odorata Beauv. （HiO7; 7 years）; （c） Thymus mongoficus Ronnm （ThM15; 15 years）; （d） Artemisia sacrorum Ledeb （AtS25; 25 years）; （e） Stipa bungeana Trin Ledeb （StB36; 36 years） and （f） Stipa grandis P. Smirn （StG56; 56 years）. The results showed that the concentrations of soil organic carbon, total nitrogen and available phosphorus increased with the increase of restoration time except for ThM15. The concen- tration of NH4-N increased in the medium stage （for ThM15 and AtS25） and decreased in the later stage （for StB36 and StG56） of vegetation restoration. However, NO3-N concentration significantly increased in the later stage （for StB36 and StG56）. Carbon fractions had a similar increasing trend during natural vegetation restoration. The con- centrations of POC, HS-C, fA-C and HA-C accounted for 24.5%-49.1%, 10.6%-15.2%, 5.8%-9.1% and 4.6%-6.1% of total carbon, respectively. for AbG3, the relative changes of POC, HS-C and fA-C were significantly higher than that of total carbon during the process of revegetation restoration. The higher relative increases in POC, HS-C and fA-C confirmed that soil carbon induced by vegetation restoration was sequestrated by higher physical and chemical protection. The increases of soil C fractions could also result in higher ecological function in semiarid grassland ecosystems.

关键词： particulate organic carbon humus carbon humic acid carbon fulvic acid carbon carbon fraction natural vegetation succession

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On the Integrability of the Abel and of the Extended Liénard Equations

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Acta Mathematicae Applicatae Sinica 2019年第4期35卷 722-736页

作者： man Kwong Mak Tiberiu HARKO Departamento de fsica Facultad de Ciencias Naturales Universidad de Atacama Copayapu 485 Copiapo Chile Department of Physics Babes-Bolyai University Kogalniceanu Street Cluj-Napoca 400084 Romania School of Physics Sun Yat-Sen University Guangzhou 510275 China

We present some exact integrability cases of the extended Liénard equation y′′+ f(y)(y′)n +k(y)(y′)m + g(y)y′+ h(y) = 0, with n > 0 and m > 0 arbitrary constants, while f(y), k(y), g(y), and h(y) are arbitrary functions. The solutions are obtained by transforming the equation Liénard equation to an equivalent first kind first order Abel type equation given bydv/dy= f(y)v3-n+ k(y)v3-m+ g(y)v2+ h(y)v3, with v = 1/y′.As a first step in our study we obtain three integrability cases of the extended quadratic-cubic Liénard equation,corresponding to n = 2 and m = 3, by assuming that particular solutions of the associated Abel equation are known. Under this assumption the general solutions of the Abel and Liénard equations with coefficients satisfying some differential conditions can be obtained in an exact closed form. With the use of the Chiellini integrability condition, we show that if a particular solution of the Abel equation is known, the general solution of the extended quadratic cubic Liénard equation can be obtained by quadratures. The Chiellini integrability condition is extended to generalized Abel equations with g(y) ≡ 0 and h(y) ≡ 0, and arbitrary n and m, thus allowing to obtain the general solution of the corresponding Liénard equation. The application of the generalized Chiellini condition to the case of the reduced Riccati equation is also considered.

关键词： Abel equation Liénard equation general solutions integrability conditions

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Effect of mineral admixtures and repeated loading on chloride migration through concrete

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第9期11卷 683-690页

作者： Wu-man ZHANG Heng-jing BA School of Transportation Science and Engineering Beihang University Beijing 100191 China School of Civil Engineering Harbin Institute of Technology Harbin 150006 China

The effect of fly ash (fA) and ground granulated blast furnace slag (GGBfS) on chloride migration through concrete subjected to repeated loading was examined. Portland cement was replaced by three percentages (20%, 30%, and 40%) of mineral admixtures. five repeated loadings were applied to concrete specimens using a WHY series fully automatic testing machine. The maximum loadings were 40% and 80% of the axial cylinder compressive strength (f′c). Chloride migration through concretes was evaluated using the rapid chloride migration test and the chloride concentration in the anode chamber was measured. The results showed that the replacement percentages of mineral admixtures, the curing time and repeated loading had a significant effect on chloride migration through concrete. The transport number of chloride through concrete cured for 28 d increased with increasing fA replacement and markedly decreased with extension of the curing time. 20% and 30% GGBfS replacement decreased the transport number of chloride through concrete, but 40% GGBfS replacement increased the transport number. five repeated loadings at 40% or 80% f′c increased the transport number of chloride for all mixes.

关键词： Concrete fly ash (fA) Ground granulated blast furnace slag (GGBfS) Chloride migration Repeated loading

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Endpoint Estimates of Generalized Homogeneous Littlewood–Paley g-functions over Non-Homogeneous Metric Measure Spaces

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Acta Mathematica Sinica,English Series 2016年第9期32卷 1035-1074页

作者： Xing fU Ji man ZHAO School of Mathematical Sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education Beijing 100875 P. R. China

Let （x, d,u） be a metric measure the upper doubling conditions. Under the weak space satisfying both the geometrically doubling and reverse doubling condition, the authors prove that the generalized homogeneous Littlewood-Paley g-function gr （r ∈ [2, ∞）） is bounded from Hardy space H1（u） into L1（u）. Moreover, the authors show that, if f ∈ RBMO（u）, then [gr（f）]r is either infinite everywhere or finite almost everywhere, and in the latter case, [gr（f）]r belongs to RBLO（u） with the norm no more than ｜｜f｜｜ RBMO（u） multiplied by a positive constant which is independent of f. As a corollary, the authors obtain the boundedness of gr from RBMO（u） into RBLO（u）. The vector valued Calderon-Zygmund theory over （X, d, u） is also established with details in this paper.

关键词： Non-homogeneous metric measure space generalized homogeneous Littlewood-Paley g-function Hardy space RBMO(u) RBLO(u) vector valued Calderon Zygmund theory

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Self-normalized Cramer-type Moderate Deviations for functionals of Markov Chain

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Acta Mathematicae Applicatae Sinica 2020年第2期36卷 294-313页

作者： Xin-wei fENG Qi-man SHAO Zhongtai Securities Institute for financial Studies Shandong UniversityJinan 250100China Department of Statistics The Chinese University of Hong KongShatinN.T.Hong KongChina Department of Statistics and Data Science Southern University of Science and TechnologyShenzhen 518000China

Let{xn,n≥0}be a Markov chain with a countable state space S and let f(·)be a measurable function from S to R and consider the functionals of the Markov chain yn:=f(xn).We construct a new type of self-normalized sums based on the random-block scheme and establish a Crame′r-type moderate deviations for self-normalized sums of functionals of the Markov chain.

关键词： self-normalized partial sums Cramer-type moderate deviations Markov Chain ergodic

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