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Journal of Rare Earths 2024年第3期42卷 578-585,I0006页

作者： Saiqa Hafeez Saima Perveen Muhammad Zarrar Khan Awab Hashmi Fahad Azad School of Natural Sciences(SNS) National University of Sciences and Technology(NUST)IslamabadPakistan Electronic and Magnetic Materials Laboratory School of Chemical and Materials Engineering(SCME)National University of Sciences and Technology(NUST)IslamabadPakistan

The present research investigated the effect of reduced graphene oxide(rGO) integration with assynthesized Er_(2)O_(3)/ZnO nanocomposites on dielectric properties. The samples were characterized by Xray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), diffuse reflectance spectroscopy(DRS), and energy dispersive spectroscopy(EDS). Complex impedance spectroscopy was utilized to characterize dielectric relaxation phenomena in Er_(2)O_(3)/ZnO and Er_(2)O_(3)/ZnO/rGO nanocomposites. All the samples exhibit single relaxation phenomena which are ascribed to grain boundaries. The addition of rGO to Er_(2)O_(3)/ZnO nanocomposite results in the enhancement of dielectric response due to increased local field intensity caused by the formation of conductinginsulating interfaces. Furthermore, the AC conductivity of the Er_(2)O_(3)/ZnO/rGO is increased at higher frequencies due to the presence of free charge carriers in rGO. At higher frequencies, Er_(2)O_(3)/ZnO/rGO nanocomposite with increased concentration of ZnO exhibits a more stable dielectric constant with extremely low dielectric loss. Hence, the inclusion of rGO in Er_(2)O_(3)/ZnO nanocomposites makes it a novel prospective candidate in the field of energy storage devices.

关键词： Erbium oxide(Er_(2)O_(3)) Rare earths Stable dielectric constant Impedance Polarization Grain boundaries

Enhancing high-temperature oxidation resistance(at 1000 °C) of nickel superalloy obtained by laser powder bed fusion via reactive electric spark treatment

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Transactions of Nonferrous Metals Society of China 2024年

作者： S.K.MUKANOV M.I.PETRZHIK A.E.KUDRYASHOV E.A.NAUMOVA F.A.BASKOV P.A.LOGINOV E.A.LEVASHOV National University of Science and Technology misis

The high-temperature oxidation resistance of the nickel superalloy grown by the Laser Powder Bed Fusion (LPBF) has been significantly increased as a result of in-situ formation of a thermal barrier layer (α-Al2O3+ CaMoO4) during oxidative annealing of surface layers modified by electric spark treatment (EST). The reactive EST of the LPBF-built items based on nickel EP741NP alloy was carried out with low-melting Al-12%Si， Al-6%Ca-0.6%Si and Al-7%Ca-1%Mn electrodes. It was found that at EST done by Al-7%Ca-1%Mn electrode an intermetallic (β-NiAl + γ’-Ni3Al) 15 microns thick layer reinforced by spherical oxide (CaMe)O nanoparticles was formed. Formation of that structure increases the wear resistance of LPBF nickel superalloy by 4.5 times. Further oxidative annealing at 1000 °C lead to a formation of continuous two-layered coating with an inner layer of α-Al2O3and an outer layer of CaMoO4， which together act as an effective barrier preventing the diffusion of oxygen into the volume of the superalloy.

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Al-Ca-Cu三元合金体系中与铝平衡的金属间化合物

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Transactions of Nonferrous Metals Society of China 2024年第5期34卷 1380-1392页

作者： T.K.AKOPYAN T.A.SVIRIDOVA N.A.BELOV N.V.LETYAGIN A.V.KOROTITSKIY National University of Science and Technology misis 4 Leninsky pr.Moscow 119049Russia

对三元Al-Ca-Cu合金体系中与铝固溶体平衡的(Al,Cu)_(4)Ca、Al_(27)Ca_(3)Cu_(7)和Al_(8)CaCu_(4)金属间化合物的结构和性能进行全面分析。基于Al4Ca相中部分Al原子被Cu取代,将(Al,Cu)_(4)Ca金属间化合物视为线性化合物。化合物中铜的... 详细信息

对三元Al-Ca-Cu合金体系中与铝固溶体平衡的(Al,Cu)_(4)Ca、Al_(27)Ca_(3)Cu_(7)和Al_(8)CaCu_(4)金属间化合物的结构和性能进行全面分析。基于Al4Ca相中部分Al原子被Cu取代,将(Al,Cu)_(4)Ca金属间化合物视为线性化合物。化合物中铜的溶解度达到10 at.%(19 wt.%),导致化合物的晶格结构、物理和力学性能发生显著变化。例如,化合物的密度从2.22 g/cm^(3)增加到2.79 g/cm^(3),显微硬度从HV 180增加到HV 250。将Al_(27)Ca_(3)Cu_(7)相视为具有严格化学计量比和BaHg11型初始晶体结构的三元化合物,其空间群为Pm3m,晶格参数为8.514Å,密度为3.45 g/cm^(3)。Al_(8)CaCu_(4)相也是严格化学计量比的三元化合物,具有Mn_(12)Th型晶格结构,最高的显微硬度(HV 505)和密度(4.57 g/cm^(3))。属于二元(Al)+(Al,Cu)_(4)Ca相场和准二元(Al)+Al_(27)Ca_(3)Cu_(7)截面的合金,有前景作为新型天然铝基复合材料的基材。

关键词：金属间化合物 Al-Ca合金显微组织晶体结构物理性能力学性能

Assessing Multidimensional Vulnerability of Rural Areas to Flooding:An Index‑Based Approach

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International Journal of Disaster Risk Science 2024年第1期15卷 88-106页

作者： Samavia Rasool Irfan Ahmad Rana Hassam Bin Waseem Department of Urban and Regional Planning School of Civil and Environmental Engineering(SCEE)National University of Sciences and Technology(NUST)Islamabad 44000Pakistan

Vulnerability assessment is essential for understanding and launching effective flood risk reduction *** study aimed to examine the vulnerability of flood-prone rural communities in southern Punjab,Pakistan to external *** concept of vulnerability encompasses a range of dimensions,including physical,social,institutional,environmental,economic,and *** a composite index method,indices were developed for each dimension and combined to create a multidimensional measure of vulnerability.A sample of 365 communities was selected using the Yamane sampling technique,and data were collected through a questionnaire containing 65 indicators across all *** statistics and ANOVA tests were used to analyze the *** results show that communities near the Chenab River had higher attitudinal and institutional vulnerability compared to other *** attitudinal vulnerabilities were as sociated with poorly perceived flood risks and low preparedness measures,whereas institutional vulnerabilities were driven by conventional flood protection strategies,lack of institutional trust,and lack of flood risk *** research provides insights into the various components of vulnerability in flood-prone rural communities in Pakistan and demonstrates a useful methodology that can be applied to other disasters at different spatial scales.

关键词： Chenab River Flood hazard Indus River Pakistan-Rural areas:Vulnerability to flooding

Recent advances in Ir/Ru-based perovskite electrocatalysts for oxygen evolution reaction

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Rare Metals 2024年第7期43卷 2891-2912页

作者： Zhi-Qi Jiang Cheng-Zhen Fan Jun-Yu Pan Li Shao Hao Chen Erum Pervaiz Yan Dong Tong-Zhou Wang Xue-Rong Zheng Ji-Hong Li Yi-Da Deng School of Materials Science and Engineering Hainan University Department of Chemical Engineering School of Chemical and Materials Engineering (SCME)National University of Sciences & Technology (NUST) Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Nankai University

Oxygen evolution reaction(OER) is a kinetically harsh four-electron anode reaction that requires a large overpotential to provide current and is of great importance in renewable electrochemical ***/Rubased perovskite oxides hold great significance for application as OER electrocatalysts,due to that their multimetal-oxide forms can reduce the use of noble metals,and their compositional tunability can modulate the electronic structure and optimize OER ***,high operating potentials and corrosive environments pose a serious challenge to the development of durable Ir-based and Ru-based perovskite *** efforts have been dedicated to improving the Ir/Ru-based perovskite activity to enhance the efficiency;however,progress in improving the durability of Ir/Ru-based perovskite electrocatalysts has been rather *** this review,the recent research progress of Ir/Ru-based perovskites is reviewed from the perspective of heteroatom doping,structural modulation,and formation of *** dissolution mechanism studies of Ir/Ru and experimental attempts to improve the durability of Ir/Ru-based perovskite electrocatalysts are *** and outlooks for further developing Ru-and Irbased perovskite oxygen electrocatalysts are also presented.

关键词： Oxygen evolution reaction Ir/Ru-based perovskites Stability Electrocatalysts

Porous Shish-Kebab Structure Prepared from Oriented UHMWPE Films by Processing in Supercritical CO_(2)

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Chinese Journal of Polymer Science 2024年第1期42卷 97-104,I0009页

作者： Sergey A.Lermontov Aleksey V.Maksimkin Nataliya A.Sipyagina Tarek Dayyoub Alena N.Malkova Evgeniy A.Kolesnikov Elena A.Straumal Inna O.Gozhikova Saidkhodzha G.Nematulloev Dmitry V.Telyshev Institute of Physiologically Active Compounds of the Russian Academy of Sciences Chernogolovka 142432Russia Institute for Bionic Technologies and Engineering I.M.Sechenov First Moscow State Medical University(Sechenov University)Moscow 19991Russia National University of Science and Technology"misis"Moscow 119049 Russia Institute of Biomedical Systems National Research University of Electronic TechnologyZelenogradMoscow 124498Russia

For the first time, a highly crystalline porous shish-kebab structure with a high degree of crystallinity was obtained by using a combination of two methods for the formation of porous polymeric materials. A treatment procedure using supercritical carbon dioxide(sc CO_(2))was carried out for oriented ultrahigh molecular weight polyethylene(UHMWPE) films, which provided special conditions for the crystallization of dissolved UHMWPE macromolecules on the surface of oriented UHMWPE crystals. The prepared porous materials were investigated by scanning electron microscopy(SEM) and differential scanning calorimetry(DSC). The particularity of the obtained porous shish-kebab is the absence of the amorphous phase between lamellar crystals(kebabs). The obtained pores had an oval shape, and they were oriented in the orientation direction of the UHMWPE macromolecules. The pore size ranged from 0.05 μm to 4 μm. Controlling the conditions for the crystallization of the UHMWPE macromolecules using supercritical CO_(2) gives the possibility to control the size of both lamellar disks and pores formed.

关键词： UHMWPE Supercritical CO_(2) Porous shish-kebab structure

Overview of Factors Affecting Dust Deposition on Photovoltaic Cells and Cleaning Methods

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Smart Grid and Renewable Energy 2024年第1期15卷 49-78页

作者： Mamadou Tamboura Ekaterina Alexandrovna Gosteva Institute of New Materials National University of Science and Technology MISIS Moscow Russia

Dust deposition on the surface of photovoltaic (PV) cells poses a significant challenge to their efficiency, especially in arid regions characterized by desert and semi-desert conditions. Despite the pronounced impact of dust accumulation, these regions offer optimal solar radiation and minimal cloud cover, making them ideal candidates for widespread PV cell deployment. Various surface cleaning methods exist, each employing distinct approaches. Choosing an appropriate cleaning method requires a comprehensive understanding of the mechanisms involved in both dust deposition on module surfaces and dust adhesion to PV cell surfaces. The mechanisms governing dust deposition and adhesion are complex and multifaceted, influenced by factors such as the nature and properties of the dust particles, environmental climatic conditions, characteristics of protective coatings, and the specific location of the PV installation. These factors exhibit regional variations, necessitating the implementation of diverse cleaning approaches tailored to the unique conditions of each location. The first part of this article explores the factors influencing dust deposition on PV cell surfaces, delving into the intricate interplay of environmental variables and particle characteristics. Subsequently, the second part addresses various cleaning methods, offering an analysis of their respective advantages and disadvantages. By comprehensively examining the factors influencing dust accumulation and evaluating the effectiveness of different cleaning strategies, this article aims to contribute valuable insights to the ongoing efforts to optimize the performance and longevity of photovoltaic systems in diverse geographical contexts.

关键词： Solar Energy Dust Deposition Cleaning Methods

Al-Ca-Fe合金中Al_(10)CaFe_(2)化合物的形成与表征

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Transactions of Nonferrous Metals Society of China 2024年第2期34卷 361-377页

作者： N.A.BELOV T.K.AKOPYAN E.A.NAUMOVA V.V.DOROSHENKO T.A.SVIRIDOVA N.O.KOROTKOVA National University of Science and Technology misis 4 Leninsky pr.Moscow 119049Russia Baikov Institute of Metallurgy and Materials Science 49 Leninsky pr.Moscow 119991Russia

采用热力学计算和实验技术研究铝角的Al-Ca-Fe体系相图,包括液相面投影图和凝固反应。结果表明,与铝固溶体(Al)平衡的不是Al_(3)Fe相,而是一种组成符合化学式Al_(10)CaFe_(2)的三元化合物。通过包晶转变L+Al_(3)Fe→(Al)+Al_(10)CaFe_(2... 详细信息

采用热力学计算和实验技术研究铝角的Al-Ca-Fe体系相图,包括液相面投影图和凝固反应。结果表明,与铝固溶体(Al)平衡的不是Al_(3)Fe相,而是一种组成符合化学式Al_(10)CaFe_(2)的三元化合物。通过包晶转变L+Al_(3)Fe→(Al)+Al_(10)CaFe_(2)(638℃,3.3%Ca和0.5%Fe,摩尔分数)发生从二元化合物到三元化合物的转变。与针状Al_(3)Fe相夹杂物不同,三元化合物的初晶和共晶具有致密的形貌。使用第一性原理计算和X射线衍射分析确定三元化合物Al_(10)CaFe_(2)的晶格结构。此外,近共晶合金Al-6%Ca-1%Fe(质量分数)在500~600℃退火后具有细晶组织,过量相的总体积分数约为25%。因此,Al-Ca-Fe体系可用于制造新的铝基复合合金。

关键词： Al-Ca合金金属间化合物相图相变显微组织铝基复合材料

High-speed performance self-powered short wave ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)

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Journal of Semiconductors 2024年第4期45卷 56-62页

作者： Aleksei Almaev Alexander Tsymbalov Bogdan Kushnarev Vladimir Nikolaev Alexei Pechnikov Mikhail Scheglov Andrei Chikiryaka Petr Korusenko Research and Development Center for Advanced Technologies in Microelectronics National Research Tomsk State UniversityTomsk 634050Russia Fokon LLC Kaluga 248035Russia Department of Semiconductor Electronics and Physics of Semiconductors National University of Science and Technology MISISMoscow 119049Russia Perfect Crystals LLC Saint Petersburg 194223Russia Department of Solid-State Electronics Saint Petersburg State UniversitySaint Petersburg 199034Russia Department of Physics Omsk State Technical UniversityOmsk 644050Russia

High-speed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with Pt contacts were demonstrated and their properties were studied in ***κ(ε)-Ga_(2)O_(3)layers were deposited by the halide vapor phase epitaxy on patterned GaN templates with sapphire *** spectral dependencies of the photoelectric properties of struc-tures were analyzed in the wavelength interval 200-370 *** maximum photo to dark current ratio,responsivity,detectiv-ity and external quantum efficiency of structures were determined as:180.86 ***.,3.57 A/W,1.78×10^(12) Hz^(0.5)∙cm·W^(-1) and 2193.6%,respectively,at a wavelength of 200 nm and an applied voltage of 1 *** enhancement of the photoresponse was caused by the decrease in the Schottky barrier at the Pt/κ(ε)-Ga_(2)O_(3)interface under ultraviolet *** detectors demon-strated could functionalize in self-powered mode due to built-in electric field at the Pt/κ(ε)-Ga_(2)O_(3)*** responsivity and external quantum efficiency of the structures at a wavelength of 254 nm and zero applied voltage were 0.9 mA/W and 0.46%,*** rise and decay times in self-powered mode did not exceed 100 ms.

关键词： κ(ε)-gallium oxide solar-blind shortwave ultraviolet radiation detectors self-powered operation mode

Physico−mathematical model of the voltage−current characteristics of light-emitting diodes with quantum wells based on the Sah−Noyce−Shockley recombination mechanism

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Journal of Semiconductors 2024年第8期45卷 25-33页

作者： Fedor I.Manyakhin Dmitry O.Varlamov Vladimir P.Krylov Lyudmila O.Morketsova Arkady A.Skvortsov Vladimir K.Nikolaev Dinamics Strength of Machines and Resisance of MaterialsMoscow Polytechnic UniversityRussia Biomedical and Electronic Means and Technologies Vladimir State UniversityRussia Computer-Aided Design and Engineering National University of Science and Technology"MISiS"Russia

Herein,a physical and mathematical model of the voltage−current characteristics of a p−n heterostructure with quantum wells(QWs)is prepared using the Sah−Noyce−Shockley(SNS)recombination mechanism to show the SNS recombination rate of the correction function of the distribution of QWs in the space charge region of diode configuration.A comparison of the model voltage−current characteristics(VCCs)with the experimental ones reveals their *** technological parameters of the structure of the VCC model are determined experimentally using a nondestructive capacitive approach for determining the impurity distribution profile in the active region of the diode structure with a profile depth resolution of up to 10Å.The correction function in the expression of the recombination rate shows the possibility of determining the derivative of the VCCs of structures with QWs with a nonideality factor of up to 4.

关键词： light-emitting diodes with quantum wells voltage−current relation nonideality factor recombination mechanism Sah−Noyce−Shockley model