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Plasma Science and Technology 2023年第2期25卷 58-67页

作者： abba alhaji bala 朱平李浩龙丁永华刘家兴万遂何莹李达王能超饶波王之江 International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China School of Physics Huazhong University of Science and TechnologyWuhan 430074People's Republic of China Department of Physics Federal University DutseJigawa 720101Nigeria Department of Engineering Physics University of Wisconsin-MadisonMadisonWisconsin WI-53706 United States of America College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060People's Republic of China

In this work,several key scaling laws of the quasi-static magnetic compression of field reversed configuration(FRC)plasma(Spencer et al 1983 *** 261564)are amended from a series of two-dimensional FRC MHD equilibriums numerically obtained using the Grad–Shafranov equation solver *** on the new scaling for the elongation and the magnetic fields at the separatrix and the wall,the empirically stable limits for the compression ratio,the fusion gain,and the neutron yield are evaluated,which may serve as a more accurate estimate for the upper ceiling of performance from the magnetic compression of FRC plasma as a potential fusion energy as well as neutron source devices.

关键词： magneto-hydrodynamic equilibrium Grad-Shafranov equation field reversed configuration NIMEQ magnetic compression

The spectrum analysis of RMP coils with multiple connection modes and the design of high field side coils on J-TEXT

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Plasma Science and Technology 2022年第12期24卷 224-231页

作者： Zhengkang REN Da Li Nengchao WANG Feiyue MAO Zhuo HUANG Song ZHOU Ruo JIA Ying HE Chengshuo SHEN abba alhaji bala Bo RAO Yonghua DING the J-TEXT Team International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China College of Computer Science South-Central Minzu UniversityWuhan 430074People's Republic of China Physics Department Federal University DutseDutse 720101Nigeria

The phase difference Δξ between locked islands(2/1 and 3/1) has been found to influence the heat transport on the thermal quench during disruptions by numerical modeling [Hu Q et al *** 59,016005].To verify this experimentally,a set of resonant magnetic perturbation(RMP) coils is required to excite coupled magnetic islands with different Δξ.The spectrum analysis shows that the current RMP coils on J-TEXT can only produce sufficient 2/1 and 3/1RMP fields with a limited phase difference of Δξ∈[-75°,75°].In order to broaden the adjustable range of Δξ,a set of coils on the high field side(HFS) is proposed to generate 2/1 and 3/1 RMP fields with Δξ=180°.As a result,RMPs with adjustable Δξ∈[-180°,180°] and sufficient amplitudes could be achieved by applying the HFS coils and the low field side(LFS)*** work provides a feasible solution for flexible adjustment of the phase difference between m and m+1 RMP,which might facilitate the study of major disruptions and their control.

关键词： resonant magnetic perturbation spectrum analysis phase difference between 2/1 and 3/1 islands

Investigation of the J-TEXT plasma events by k-means clustering algorithm

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Plasma Science and Technology 2023年第8期25卷 38-43页

作者：李建超张晓卿张昱 abba alhaji bala 柳惠平周帼红王能超李达陈忠勇杨州军陈志鹏董蛟龙丁永华 the J-TEXT Team Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of TechnologyWuhan 430205People's Republic of China International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Department of Physics Federal University DutseJigawa 720101Nigeria 不详

Various types of plasma events emerge in specific parameter ranges and exhibit similar characteristics in diagnostic signals,which can be applied to identify these events.A semisupervised machine learning algorithm,the k-means clustering algorithm,is utilized to investigate and identify plasma events in the J-TEXT *** method can cluster diverse plasma events with homogeneous features,and then these events can be identified if given few manually labeled examples based on physical understanding.A survey of clustered events reveals that the k-means algorithm can make plasma events(rotating tearing mode,sawtooth oscillations,and locked mode)gathering in Euclidean space composed of multi-dimensional diagnostic data,like soft x-ray emission intensity,edge toroidal rotation velocity,the Mirnov signal amplitude and so *** on the cluster analysis results,an approximate analytical model is proposed to rapidly identify plasma events in the J-TEXT *** cluster analysis method is conducive to data markers of massive diagnostic data.

关键词： k-means cluster analysis plasma event machine learning

Study of the spectrum effect on the threshold of resonant magnetic perturbation penetration on J-TEXT

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Plasma Science and Technology 2022年第12期24卷 16-25页

作者： Feiyue MAO Nengchao WANG Zhuo HUANG Zhengkang REN Song ZHOU Chengshuo SHEN Xiaoyi ZHANG Ying HE Qi ZHANG Ruo JIA Chuanxu ZHAO Yangbo LI Bo HU Da Li abba alhaji bala Zhipeng CHEN Zhongyong CHEN Zhoujun YANG Yunfeng LIANG Yonghua DING Yuan PAN the J-TEXT Team International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China College of Computer Science South-Central Minzu UniversityWuhan 430074People's Republic of China Physics Department Federal University DutseDutse 720101JigawaNigeria Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung-PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)Jülich 52425Germany Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China

The spectrum effect on the penetration of resonant magnetic perturbation(RMP) is studied with upgraded in-vessel RMP coils on *** poloidal spectrum of the RMP field,especially the amplitudes of 2/1 and 3/1 components,can be varied by the phase difference between the upper and lower coil rows,ΔΦ=Φ_(top)-Φ_(bottom),where Φ_(top)and Φ_(bottom)are the toroidal phases of the n=1 field of each coil *** type of RMP penetration is found to be related to ΔΦ,including the RMP penetration of either 2/1 or 3/1 RMP and the successive penetrations of 3/1 RMP followed by the 2/1 *** cases with penetration of only one RMP component,the penetration thresholds measured by the corresponding resonant component are close for variousΔΦ.However,the 2/1 RMP penetration threshold is significantly reduced if the 3/1 locked island is formed in *** changes in the rotation profile due to 3/1 locked island formation could partially contribute to the reduction of the 2/1 thresholds.

关键词： tokamak error field resonant magnetic perturbation mode penetration spectrum analysis

Petrogenesis and Tectonic Implications of Peralkaline A-Type Granites and Syenites from the Suizhou-Zaoyang Region,Central China

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Journal of Earth Science 2018年第5期29卷 1181-1202页

作者： Hafizullah abba Ahmed Changqian Ma Lianxun Wang Ladislav A.Palinkas Musa bala Girei Yuxiang Zhu Mukhtar Habib State Key Laboratory of Geological Processes and Mineral Resources School of Earth SciencesChina University of GeosciencesWuhan 430074China Department of Geology Modibbo Adama University of TechnologyYola P.M.B.2076Nigeria Institute of Mineralogy and Petrology Faculty of SciencesUniversity of ZagrebZagreb HR-10000Croatia Department of Geology Faculty of Earth and Environmental SciencesBayero UniversityKanoNigeria Department of Mineral and Petroleum Resources Engineering Kaduna PolytechnicKadunaNigeria

In this study, we present systematic petrological, geochemical, LA-ICP-MS zircon U-Pb ages and Nd isotopic data for the A-type granites and syenites from Suizhou-Zaoyang region. The results show that the peralkaline A-type granites and syenites were episodically emplaced in Suizhou-Zaoyang region between 450±3 and 441±7 Ma which corresponds to Late Ordovician and Early Silurian periods, respectively. Petrologically, the syenite-peralkaline granite association comprises of nephefine normative-syenite and alkaline granite in Guanzishan and quartz normative syenite and alkafine granite in Huangyangshan. The syenite-granite associations are ferroan to alkali in composition. They depict characteristics of typical OIB （oceanic island basalts） derived A-type granites in multi-elements primitive normalized diagram and Ybffa vs. Y/Nb as well as Ce/Nb vs. Y/Nb binary plots. Significant depletion in Ba, Sr, P, Ti and Eu indicates fractionation of feldspars, biotite, amphiboles and Ti-rich augite. The values of eNd（t） in Guanzishan nepheline syenite and alkaline granite are ＋1.81 and ＋2.26, respectively and the calculated two-stage model age for these rocks are 1 040 and 1 003 Ma, respectively. On the other hand, the Huangyangshan alkaline granite has eNd（t） values ranging from ＋2.61 to ＋3.46 and a relatively younger two-stage Nd model age values ranging from 906 to 975 Ma, respectively. Based on these data, we inferred that the Guanzishan nepheline syenites and granites were formed from fractional crystallization of OIB-like basic magmas derived from upweliing of metasomatized lithospheric mantle. The Huangyangshan quartz syenite and granite on the other hand, were formed from similar magmas through fractional crystallization with low input from the ancient crustal rocks. Typically, the rocks exhibit Al-type granite affinity and classified as within plate granites associated with the Ordovician crustal extension and the Silurian rifting.

关键词： Huangyangshan Guanzishan OIB derived A-type granites nepheline syenite alkaline granite South Qinling Suizhou-Zaoyang region.

Weed Species Composition in Paddy Field of Usur Town,Bade Local Government,Yobe State,Nigeria

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Journal of Botanical Research 2023年第2期5卷 29-48页

作者： Mohammed alhaji Bello Halima Mohammed abba Umar Mohammed Department of Biological Science Education School of SciencesUmar Suleiman College of Education GashuaP.M.B.02Yobe StateNigeria Department of Botany Faculty of SciencesGombe State UniversityGombe State760211Nigeria Department of Agricultural Science Education School of Vocational EducationUmar Suleiman College of Education GashuaP.M.B.02Yobe StateNigeria

Farmers are eager to know the various types of weeds in paddy *** will help in choosing the best weed management practice for effective weed control as well as reducing rice yield *** objectives of the study are to identify the weeds species affecting the rice field,to assess the composition of weeds species,to classify the weed species into different families,genera,species,common names,Hausa names,lifecycles,life forms,native/exotic species,propagation and uses,and to determine the dominant weed *** vegetation surveys were *** observed were photographed,and prepared as herbarium *** key manuals and checklists were utilized for weed identification and later organized using the Angiosperm Phylogeny Group(APG)classification system.A total number of 72 plants species distributed within 16 families and 50 genera were *** annuals(66.67%)were the dominant weed followed by perennials(33.33%)while biennials were the *** broad leaves were the dominant weed(44.61%)identified followed by Poaceae(27.7%)and Sedges(11.11%).Results obtained from this study could be useful in choosing the best management practice and in making a decision on the choice of herbicides and directing research towards improved weed control measures.

关键词： Rice Dominant weeds Exotic species Native species Weed classification

Review of Agro Waste Plastic Composites Production

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Journal of Minerals and Materials Characterization and Engineering 2013年第5期1卷 271-279页

作者： Hammajam alhaji abba Ismarrubie Zahari Nur Sapuan Mohd Salit Department of Mechanical and Manufacturing Engineering Universiti Putra MalaysiaSelangor Malaysia

This article reviews the literature reports base on agro waste plastic composites using different fiber as fillers and reinforcements. Various processing methods and conditions;compression molding process, injection molding, and extrusion method are used in the composites productions. Characterization challenges associated with the agro waste plastic composites productions were also examined. Thus, the findings of this research review can be use as a data base for further inquiring into the agro waste plastic composites in a view to enhance the development of the sector.

关键词： Agro Waste Plastic Composite Characterization Production

Development and Evaluation of the Mechanical Properties of Coconut Fibre Reinforced Low Density Polyethylene Composite

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Open Journal of Composite Materials 2022年第3期12卷 83-97页

作者： Ahmed Mohammed Bukar Abubakar Mohammed El-Jummah abba alhaji Hammajam Department of Mechanical Engineering University of Maiduguri Maiduguri Nigeria

This research work developed and evaluated the mechanical properties of coconut fibre reinforced low density polyethylene (LPDE) composite material. The effect of fibre loading on the mechanical properties: tensile, flexural, and impact of the developed composite material have been investigated. Also carried out was the effect of fibre loading on the water absorptivity of the developed material. Sample categories of the developed composite were prepared by varying the fibre contents by weight at 0%, 10%, 20%, and 30%. The aim is to reduce the excessive waste disposal of LDPE materials that are largely found in the form of disposed water package materials (or pure water sachets) that usually affects the environment in the form of pollution. The water retting process was applied in extracting and cleaning fibre (or coir), while the mixed coir-LDPE (or developed composite material) was prepared by Compression Moulding Technique (CMT). The tensile and flexural properties were tested using Hounsfield Monsanto Tensometer (type w) while the impact properties were tested using the Charpy Impact testing machine. The microstructure of the composite was investigated using Scanning Electron Microscopy (SEM). The fractured surface morphology of the composite samples indicated a homogeneous mixture of the coir fibre and LDPE matrix. However, weak interfacial bonding between the coir fibre and LDPE matrix was also observed. The analysis of the water absorptivity showed that the developed composite materials have low water absorptivity at low fibre loading. However, at higher fibre loading, the water absorptivity increases significantly.

关键词： Coconut Fibre Low Density Polyethylene Composite Mechanical Properties Water Absorptivity

The Green Composites: Millet Husk Fiber (MHF) Filled Poly Lactic Acid (PLA) and Degradability Effects on Environment

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Open Journal of Composite Materials 2019年第3期9卷 300-311页

作者： abba alhaji Hammajam Abubakar Mohammed El-Jummah Zahari Nur Ismarrubie Department of Mechanical Engineering University of Maiduguri Maiduguri Nigeria Department of Mechanical and Manufacturing Engineering Universiti Putra Malaysia Serdang Selangor Malaysia

This study provides an overview on green composites degradability. Practically, the main drawbacks of using natural fibers are their poor dimensional stability, degradability and high degree of moisture absorption. While, end use of product from natural fiber filled or reinforced composites has become subject of concern to material engineers and scientist. The major properties of natural fiber reinforced polymer composites are greatly dependent on the hydrophilic tendency and dimensional stability of the fibers used, morphology aspect ratio for long fiber, while voids for powder fibers. The effects of chemical treatments on cellulosic fibers that are used as reinforcements for thermoplastics were studied. The chemical source for the treatments is alkalization. The significance of chemically-treated natural fibers is seen through the improvement of mechanical properties. The untreated fiber composites degrade faster in municipal soil compared to treated fiber composites.

关键词： Degradability Composite Fibers Poly Lactic Acid Millet Husk

过渡金属-沸石咪唑框架材料用作低成本高效的氧还原反应电催化剂

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过渡金属-沸石咪唑框架材料用作低成本高效的氧还原反应电催化剂

作者： Musa abba bala 北京化工大学

学位级别：硕士

燃料电池和金属-空气电池是最有前途的清洁能源系统,其电化学过程很大程度上依赖于催化氧还原反应(ORR)。然而,阴极上的反应往往受到ORR反应动力学的限制,缓慢的反应动力学导致电池(燃料电池和金属-空气电池)性能低下。采用高效阴极电... 详细信息

燃料电池和金属-空气电池是最有前途的清洁能源系统,其电化学过程很大程度上依赖于催化氧还原反应(ORR)。然而,阴极上的反应往往受到ORR反应动力学的限制,缓慢的反应动力学导致电池(燃料电池和金属-空气电池)性能低下。采用高效阴极电催化剂是降低ORR过电位、实现快速反应动力学和提高器件性能的有效途径之一。Pt基催化剂是目前最好的阴极催化剂,具有最好的ORR电催化性能,但其昂贵的成本是其商业化的主要障碍。因此,开发低成本、高效的非贵金属催化剂具有重要的实际应用价值。近年来,含铁氮掺杂MOFs衍生的碳和碳负载的MOFs材料因其良好的ORR性能而受到广泛的关注,显示出替代商业Pt/C催化剂的潜力。开发经济高效的非贵金属催化剂用于酸性和碱性介质的ORR是清洁能源生产的迫切需要。单原子催化剂显著改善了ORR的性能,然而,催化剂结构溶解导致的活性衰减仍然是一个挑战。因此,我们提出了一种简单的保护SAC结构的策略,即用Fe-N修饰Fe-ZI-LF衍生碳纳米管,命名为Fe SA@CNTs。Fe SA@CNTs催化剂在碱性介质中表现出良好的ORR性能,起始电位E=0.998 V,半波电位E=0.898 V,分别比商业20%Pt/C催化剂高28 m V和29 m V。此外,Fe SA@CNTs在酸性介质中表现出较高的半波电位(E=0.8290 V),与Pt/C(E=0.8292 V)相当,这优于最近报道的ORR催化剂性能。密度泛函理论(DFT)表明,Fe-N中的Fe和O的能量轨道差较小,改善了速率决定步骤中电子转移到反应中间体(OH*)上的速度,使Fe SA@CNTs在酸性和碱性介质中都具有更高的催化活性。在不添加表面活性剂的条件下,将双金属ZIFs晶体在还原石墨烯薄片(r GO)上水热生长,制备了Co Ni-ZIF/r GO。在相同的测试条件下,所制备的复合材料的ORR催化性能优于原始的Co Ni-ZIF。通过物理和化学表征来测量材料的性能。结果表明,在碱性介质中,Co Ni-ZIF/r GO有利于催化氧还原反应。值得注意的是,Co Ni-ZIF/r GO的半波电位为0.865 V,超过了商业20%Pt/C(0.860 V RHE),反应过程显示近4个电子转移途径。ZIFs与r GO纳米片之间的协同作用促进了反应中间体的电子快速转移和吸附,从而提高了电催化活性。

关键词：过渡金属掺杂ZIF 电催化氧还原反应单原子碳纳米管 Pristine MOF