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Highly efficient and stable electrooxidation of methanol and ethanol on 3D Pt catalyst by thermal decomposition of In2O3 nanoshells

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Journal of Energy Chemistry 2017年第1期26卷 193-199页

作者： Yuhang Xie Hulin Zhang Guang Yao saeed ahmed khan Xiaojing Cui Min Gao Yuan Lin State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054SichuanChina Center for Information in Medicine University of Electronic Science and Technology of ChinaChengdu 610054SichuanChina The First Sub-Institute Nuclear Power Institute of ChinaChengdu 610041SichuanChina

In this paper In2O3nanoshells have been synthesized via a facile hydrothermal approach. The nanoshells can be completely cracked into pony-size nanocubes by annealing, which are then used as a support of Pt catalyst for methanol and ethanol electrocatalytic oxidation. The prepared In2O3and supported Pt catalysts (Pt/In2O3) were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), field effect scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were carried out, indicating the excellent catalytic performance for alcohol electrooxidation can be achieved on Pt/In2O3nanocatalysts due to the multiple active sites, high conductivity and a mass of microchannels and micropores for reactant diffusions arising from 3D frame structures compared with that on the Pt/C catalysts. © 2016 Science Press

关键词： Alcohols Catalyst activity Catalysts Chronoamperometry Cyclic voltammetry Decomposition Electrocatalysis Electrochemical impedance spectroscopy Electron microscopy Electrooxidation Energy dispersive spectroscopy Ethanol High resolution transmission electron microscopy Methanol Nanoshells Nanostructured materials Nanostructures Platinum Scanning electron microscopy Transmission electron microscopy X ray diffraction X ray photoelectron spectroscopy X ray spectroscopy

MWCNTs based flexible and stretchable strain sensors

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Journal of Semiconductors 2017年第5期38卷 18-23页

作者： saeed ahmed khan Min Gao Yuechang Zhu Zhuocheng Yan Yuan Lin State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China

Carbon nanotubes have potential applications in flexible and stretchable devices due to their remarkable electromechanical *** and stretchable strain sensors of multi-walled carbon nanotubes（MWCNTs）with aligned or random structures were fabricated on poly-dimethylsiloxane（PDMS） substrate with different *** was observed that the spraycoatedtechniquebased strain sensor fabricated on PDMS substrate showed higher sensitivity higher stretchability,better linearity and excellent longer time stability than the sensor fabricated with other methods presented in this *** scanning electron microscopy images indicated the spray coating technique can produce a better uniform and compact CNT network,which is the important role affecting the performance of CNT-based flexible strain sensors.

关键词： strain sensor stretchable sensor carbon nanotube arrays

计及电动汽车可调度能力的风/车协同参与机组组合策略

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高电压技术 2018年第10期44卷 3433-3440页

作者：师景佳袁铁江 saeed ahmed khan 秦文萍韩肖清段贵钟电力系统运行与控制山西省重点实验室(太原理工大学) 太原030024 苏库尔伊巴大学电气工程系巴基斯坦030024

为了通过调度电动汽车充放电来消纳更多的风电,提出一种计及电动汽车可调度能力的风/车协同参与机组组合策略。将电动汽车负荷按照可调度能力划分为无序充电负荷、可调度充电负荷和可调度充放电负荷,利用车辆行驶行为特性模拟电动汽车... 详细信息

为了通过调度电动汽车充放电来消纳更多的风电,提出一种计及电动汽车可调度能力的风/车协同参与机组组合策略。将电动汽车负荷按照可调度能力划分为无序充电负荷、可调度充电负荷和可调度充放电负荷,利用车辆行驶行为特性模拟电动汽车出行规律,建立电动汽车状态矩阵和电动汽车可调度充放电容量模型。将电动汽车充放电负荷作为机组组合中的变量,建立电动汽车与风力发电协同参与的机组组合模型。从经济效益角度分析当汽车充放电采用分时电价模式,运营商在不同类型可调度电动汽车互相组合情况下,常规机组运行费用、风电弃风量以及调度电动汽车充放电时运营商获益情况和用户充电花费情况。算例分析结果表明电网通过合理调度电动汽车充放电可以提高风电消纳能力并降低车网互动成本。

关键词：电动汽车机组组合电动汽车与电网互动可调度容量风电消纳

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基于绝对潮流的关键线路辨识方法

太原理工大学学报 2017年第4期48卷 602-607页

作者：贾燕冰何海丹谢栋袁铁江 saeed ahmed khan 太原理工大学电力系统运行与控制山西省重点实验室山西太原030024 国网新疆电力公司乌鲁木齐供电公司新疆乌鲁木齐830002 国网浙江省电力公司绍兴供电公司浙江绍兴312000 苏库尔工商管理学院

针对电力系统中关键线路辨识受系统的运行状态影响、很难快速准确地进行辨识的问题,结合电网实际潮流、绝对潮流、节点性质以及线路输电容量等因素,根据发电机支路功率分布因子、绝对潮流因子和线路权重因子,提出了基于加权绝对潮流因... 详细信息

针对电力系统中关键线路辨识受系统的运行状态影响、很难快速准确地进行辨识的问题,结合电网实际潮流、绝对潮流、节点性质以及线路输电容量等因素,根据发电机支路功率分布因子、绝对潮流因子和线路权重因子,提出了基于加权绝对潮流因子来进行关键线路辨识。采用连续攻击后系统的切负荷量及全局效能函数对系统的脆弱性进行评估,经IEEE-39和IEEE-57节点系统算例对比了采用绝对潮流和潮流进行关键线路辨识的效果,验证了算法的有效性。结果表明,本文所提出的算法可以提高关键线路辨识的准确度和速度,对于指导电力系统规划和调度运行具有指导意义。

关键词：关键线路辨识绝对潮流因子电网效能函数功率分布因子权重因子

CTAB-assisted fabrication of hierarchical flower-like magnesium oxide adsorbent for enhanced removal performance towards phosphate

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Journal of Magnesium and Alloys 2023年第9期11卷 3231-3240页

作者： saeed ahmed State Key Laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical TechnologyBeijing 100029China Department of Chemistry The University of LahoreLahore 54590Pakistan Department of Chemistry University of ChakwalPakistan

In this work, a series of hierarchical flower-like magnesium oxide(MgO) adsorbents were successfully fabricated in a cetyltrimethylammonium bromide(CTAB) assisted solvothermal route using hexamethylenetetramine(HMTA) as a precipitating agent. Effects of CTAB feeding amount on the structure, morphology, pore structure, and corresponding adsorption behavior were investigated. The hierarchical gardenias flower-like MgO demonstrated a surface area of 336.54 m^(2)·g^(-1) at a minimum ratio of the CTAB/Mg^(2+)was 0.02 in the reaction system. The hierarchical MgO phosphate removal capacity was 348.32 mg·g^(-1), which followed the pseudo-second-order and Freundlich isotherm model obtained from the large surface area and appropriate pore size. The value of n also suggests the feasible nature of phosphate adsorption under the examined conditions. Indeed, this CTAB assisted solvothermal method can provide a new understanding to tune the desired properties of a material by merely adjusting the reaction parameters of MgO.

关键词： Adsorption CTAB-assisted Magnesium oxide Phosphate removal Solvothermal

Competitive role of nitrogen functionalities of N doped GO and sensitizing effect of Bi_(2)O_(3)QDs on TiO_(2)for water remediation

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Journal of Environmental Sciences 2021年第10期33卷 107-119页

作者： Saima Noor Shamaila Sajjad Sajjad ahmed khan Leghari Cristina Flox saeed Ahmad International Islamic University Islamabad 44000Pakistan Department of Chemistry and Materials Science Aalto UniversityEspoo 16100Fl-00076Finland Pakistan Institute of Engineering and Applied Sciences Islamabad 44000Pakistan Department of Applied Physics Aalto UniversityEspoo 15100Fl-00076Finland

The promising solar irradiated photocatalyst by pairing of bismuth oxide quantum dots(BQDs)doped TiO_(2)with nitrogen doped graphene oxide(NGO)nanocomposite(NGO/BQDs-TiO_(2))was *** was used for degradation of organic pollutants like 2,4-dichlorophenol(2,4-DCP)and stable dyes,*** B and Congo Red.X-ray diffraction(XRD)profile of NGO showed reduction in oxygenic functional groups and restoring of graphitic crystal *** characteristic diffraction peaks of TiO_(2)and its composites showed crystalline anatase TiO_(2).Morphological images represent spherical shaped TiO_(2)evenly covered with BQDs spread on NGO *** surface linkages of NO-O-Ti,C-O-Ti,Bi-O-Ti and vibrational modes are observed by Fourier transform infrared spectroscopy(FTIR)and Raman *** and NGO modified TiO_(2)results into red shifting in visible region as studied in diffused reflectance spectroscopy(DRS).NGO and BQDs in TiO_(2)are linked with defect centers which reduced the recombination of free charge carriers by quenching of photoluminescence(PL)intensities.X-ray photoelectron spectroscopy(XPS)shows that no peak related to C-O in NGO/BQDs-TiO_(2)is *** indicated that doping of nitrogen into GO has reduced some oxygen functional *** functionalities in NGO and photosensitizing effect of BQDs in ternary composite have improved photocatalytic activity against organic *** byproducts during photo degradation process of 2,4-DCP were studied through high performance liquid chromatography(HPLC).Study of radical scavengers indicated that O_(2)^(·-) has significant role for degradation of 2,*** investigations propose that fabricated nanohybrid architecture has potential for degradation of environmental pollutions.

关键词： Bi_(2)O_(3)quantum dots Nitrogen doped graphene oxide Nitrogen defects TiO_(2) 2,4-Dichlorophenol Water treatment

Dielectric relaxation and conduction behaviors of Aurivillius Na_(0.5)Bi_(4.5)Ti_(4)O_(15) ceramics with Na doping

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Rare Metals 2021年第5期40卷 1247-1254页

作者： Fida Rehman Jing-Bo Li Pervaiz ahmed Muhammad Sheraz khan Yasir saeed Asma khan Muhammad Zubair Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Department of Physics Abbottabad University of Science&TechnologyHavelian 22500Pakistan Department of Physics University of Azad Jammu and KashmirMuzafarabad 13100Pakistan Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems and School of Physics Beijing Institute of TechnologyBeijing 100081China Department of Chemistry Abbottabad University of Science&TechnologyHavelian 22500Pakistan Key Laboratory of Advanced Functional Materials College of Materials Science and EngineeringMinistry of EducationBeijing University of TechnologyBeijing 100124China

Aurivillius Na_(0.5)Bi_(4.5)Ti_(4)O_(15) and Bi_(4)Ti_(3)O_(12)compounds were synthesized via solid-state reaction technique.X-ray powder diffraction study confirmed monophasic four-layered Na_(0.5)Bi_(4.5)Ti_(4)O_(15) and three-layered Bi_(4)Ti_(3)O_(12) *** relaxation and conduction behaviors of Na-contained Na_(0.5)Bi_(4.5)Ti_(4)O_(15)ceramics were thoroughly investigated in a large scale of temperature of 30-650℃ and frequency of 40 Hz^(-1) *** addition,comparative studies of both the compounds were *** and modulus analyses revealed a single relaxation behavior in Na_(0.5)Bi_(4.5)Ti_(4)O_(15) compound which was originated from the grain’s interior with grain resistance of 2.189×10^(5)Ω and capacitance of 4.268×10^(-10) F at 570℃.While in Bi_(4)Ti_(3)O_(12) ceramic the relaxation was due to the contributions of grain and grain *** current(AC)conductivity analysis revealed the presence of two different conduction regions in both the *** energies for the two different conduction mechanisms,i.e.,in low-temperature region and in high-temperature region were calculated to be~0.23 and~1.27 eV at 1 kHz for Na_(0.5)Bi_(4.5)Ti_(4)O_(15) compound and~0.43 eV and~0.97 eV at 1 kHz for Bi_(4)Ti_(3)O_(12) compound,*** present study of dielectric relaxation and conduction behaviors would be helpful for further investigations of Na_(0.5)Bi_(4.5)Ti_(4)O_(15)-related Aurivillius compounds.

关键词： Na_(0.5)Bi_(4.5)Ti_(4)O_(15) Electronic ceramics Dielectric Impedance Electrical properties

A Hybrid and Lightweight Device-to-Server Authentication Technique for the Internet of Things

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Computers, Materials & Continua 2024年第3期78卷 3805-3823页

作者： Shaha Al-Otaibi Rahim khan Hashim Ali Aftab ahmed khan Amir saeed Jehad Ali Department of Information Systems College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Department of Computer Science Abdul Wali Khan University MardanMardan23200Pakistan Department of Computer Science and IT UET PeshawarJalozai Campus PeshawarPeshawar24240Pakistan Department of AI Convergence Network Ajou UniversitySuwon16499South Korea

The Internet of Things(IoT)is a smart networking infrastructure of physical devices,i.e.,things,that are embedded with sensors,actuators,software,and other technologies,to connect and share data with the respective server *** IoTs are cornerstones in different application domains,the device’s authenticity,i.e.,of server(s)and ordinary devices,is the most crucial issue and must be resolved on a priority ***,various field-proven methodologies were presented to streamline the verification process of the communicating devices;however,location-aware authentication has not been reported as per our knowledge,which is a crucial metric,especially in scenarios where devices are *** paper presents a lightweight and location-aware device-to-server authentication technique where the device’s membership with the nearest server is subjected to its location information along with other ***,Media Access Control(MAC)address and Advance Encryption Scheme(AES)along with a secret shared key,i.e.,λ_(i) of 128 bits,have been utilized by Trusted Authority(TA)to generate MaskIDs,which are used instead of the original ID,for every device,i.e.,server and member,and are shared in the offline ***,TA shares a list of authentic devices,i.e.,server S_(j) and members C_(i),with every device in the IoT for the onward verification process,which is required to be executed before the initialization of the actual communication ***,every device should be located such that it lies within the coverage area of a server,and this location information is used in the authentication process.A thorough analytical analysis was carried out to check the susceptibility of the proposed and existing authentication approaches against well-known intruder attacks,i.e.,man-in-the-middle,masquerading,device,and server impersonations,etc.,especially in the IoT ***,proposed authentication and existing state-of-the-art approaches have been s

关键词： Internet of things authenticity security location communication

Energy-Efficient Scheduling for a Cognitive IoT-Based Early Warning System

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Computers, Materials & Continua 2022年第6期71卷 5061-5082页

作者： saeed ahmed Noor Gul Jahangir khan Junsu Kim Su Min Kim Department of Electronics Engineering Korea Polytechnic UniversitySiheung15073Korea Mirpur University of Science and Technology Mirpur10250Pakistan Department of Electronics University of PeshawarPeshawar25120Pakistan Sarhad University of Science and Information Technology Peshawar25000Pakistan

Flash floods are deemed the most fatal and disastrous natural hazards globally due to their prompt onset that requires a short prime time for emergency *** Internet of things(CIoT)technologies including inherent characteristics of cognitive radio(CR)are potential candidates to develop a monitoring and early warning system(MEWS)that helps in efficiently utilizing the short response time to save lives during flash ***,most CIoT devices are battery-limited and thus,it reduces the lifetime of the *** tackle these problems,we propose a CIoTbased MEWS to slash the fatalities of flash *** extend the lifetime of the MEWS by conserving the limited battery energy of CIoT sensors,we formulate a resource assignment problem for maximizing energy *** solve the problem,at first,we devise a polynomial-time heuristic energyefficient scheduler(EES-1).However,its performance can be unsatisfactory since it requires an exhaustive search to find local optimum values without consideration of the overall network energy *** enhance the energy efficiency of the proposed EES-1 scheme,we additionally formulate an optimization problem based on a maximum weight matching bipartite ***,we additionally propose a Hungarian algorithm-based energy-efficient scheduler(EES-2),solvable in polynomial *** simulation results show that the proposed EES-2 scheme achieves considerably high energy efficiency in the CIoT-based MEWS,leading to the extended lifetime of the MEWS without loss of throughput performance.

关键词： Flash floods internet of things cognitive radio early warning system network lifetime energy efficiency