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Tracking the origin of ultralow velocity zones at the base of Earth's mantle

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National Science Review 2021年第4期8卷 16-18页

作者： Jiuhua Chen Center for the Study of Matters at Extreme Conditions Department of Mechanical and Materials Engineering Florida International University

About three decades ago, seismological models showed that the base of the mantle is laterally heterogeneous,with two vast regions beneath Africa and the Pacific that exhibit lower-thanaverage seismic velocity, named l... 详细信息

关键词： IRON melt

melt-spun Al_(70-X)Si_(30)Mn_X (X=0,3,5,7,10) anode in lithium-ion batteries

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Science China(Technological Sciences) 2009年第8期52卷 2288-2294页

作者： SUN ZhanBo1, LI XuePeng1, WANG XiaoDong1, HU Qing1, ZHAO MingShu1, ZHU YaoMin2, LI Yan2 & SONG XiaoPing1 1 School of Science, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China 2 School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China School of Science State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University Xi’an China School of Materials Science and Engineering Henan University of Science and Technology Luoyang China

Al70-XSi30MnX (X=0, 3, 5, 7, 10, mol%) ribbons were prepared by melt spinning. A supersaturated solid solution of Si and Mn in fcc Al and some microstructures consisting of nano grains were obtained. Some alloys with nano-sized grains exhibited high discharge capacities and favorable cycle properties. The capacity of more than 400 mAh/g could be obtained in melt-spun Al67Si30Mn3 alloy after 20 cycles and more than 300 mAh/g after 40 cycles. Li/Si and Li/Al compounds in the anodes of pure Al and pure Si were not detected in Al-Si-Mn alloys inserted by Li. It is considered that the formation of the supersaturated solid solution and refinement of microstructures have prevented the alloys from the forming the compounds with superfluous Li. As a result, the electrochemical properties have been improved.

关键词： Al-Si-Mn alloy melt spinning microstructure electrochemical property

Development of high-coercivity state in melt-spun Fe41Pd41B8Si6P4 ribbons

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Rare Metals 2020年第1期39卷 76-83页

作者： Oksana Aleksandrovna Golovnia Nina Ivanovna Vlasova Aleksandr Gervasievich Popov Vasiliy Semenovich Gaviko Vladimir Vladimirovich Popov Jr. Andrey Vladimirovich Protasov Arti Kashyap M.N.Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences EkaterinburgRussia620990 Institute of Natural Sciences and Mathematics Ural Federal UniversityEkaterinburgRussia620002 Israel Institute of Metals Technion R&D FoundationTechnion City3200003HaifaIsrael Indian Institute of Technology Mandi KamandMandiHP175005India

The phase transformation and magnetic hysteresis properties of melt-spun Fe41 Pd41 B8 Si6 P4 ribbons subjected to the annealing at temperatures of 500-550℃were studied after holding for 0.1-60.0 h by transmission electron microscopy(TEM),X-ray diffraction(XRD)and thermomagnetic analysis.The additions of P,B and Si to the FePd alloy allowed us to achieve the coercivity of124 kA·m-1,which is 2.6 times higher than that of the melt-spun ribbons of the binary equiatomic FePd alloy.The high-coercivity Fe41Pd41B8 Si6 P4 alloy is nanocrystalline and is composed of the ordered L10-phase grains approximately 40 nm in size and inclusions of the Fe2(P,B)and Pd2(Si,B)phases.The coercivity kinetics is controlled by the phase transformation which can be divided into three stages:transformation from the bcc structure to nanosized regions of the fee and Fe2 P phases;transformation from the fee to L10 nanosized regions with somewhat different degrees of tetragonality and their ordering;and extensive growth of the weight fraction of L10 phase from the fee nanosized regions.P and B atoms occupy interstitial sites in the iron plane of L10 lattice,thus decreasing its Curie temperature(TC).

关键词： Fe-Pd-P-B-Si melt spinning L10 Nanostructured materials Phase transformation Magnetic measurements

Structures and hydrogen storage properties of RE-Mg-Ni-Mn-based AB2-type alloys prepared by casting and melt spinning

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Rare Metals 2019年第11期38卷 1086-1096页

作者： Yang-Huan Zhang Zhong-Hui Hou Ying Cai Feng Hu Yan Qi Dong-Liang Zhao Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010China Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China

To ameliorate the electrochemical hydrogen storage properties of RE-Mg-Ni-Mn-based AB2-type electrode alloys,La element was partially substituted by Ce,and La1-xCexMgNi3.5Mn0.5(x=0,0.1,0.2,0.3,0.4)alloys were fabricated by casting and melt spinning.The effects of Ce content on structures and electrochemical hydrogen storage properties of prepared alloys were studied in detail.Results show that the experimental alloys consist of LaMgNi4 and LaNi5 phases.The variation of Ce content,instead of changing phase composition,results in an obvious phase abundance change in the alloys,namely the amount of LaMgNi4 and LaNi5 phases,respectively,increases and decreases with Ce content growing.Moreover,the partial substitution of Ce for La leads to that the lattice keeps constant,cell volumes clearly decreases and the alloy grains are markedly refined.The electrochemical measurements reveal that the as-cast and as-spun alloys obtain the maximum discharge capacities at the first cycling without any activation needed.With Ce content increasing,the discharge capacity of as-cast alloys visibly decreases.By contrast,the as-spun alloys have the maximum discharge capacity value.The substitution of Ce for La dramatically promotes the cycle stability.Moreover,the electrochemical kinetic performances of as-cast and asspun alloys first increase and then decrease with Ce content increasing.

关键词： AB2-type alloy Ce substitution for La melt spinning Electrochemical properties

Oxygen content of high ferrotitanium prepared by thermite method with different melt separation temperatures

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Rare Metals 2019年第9期38卷 892-898页

作者： Chu Cheng Zhi-He Dou Ting-An Zhang Jian-Ming Su Hui-Jie Zhang Yan Liu Li-Ping Niu School of Metallurgy Northeastern UniversityShenyang 110819China Key Laboratory of Ecological Utilization of Multi-metal Intergrown Ores of Ministry of Education Shenyang 110819China

High ferrotitanium prepared directly by the thermite method has a disadvantageously high O content(≥10 wt%)because of the short slag-metal separation time.In this study,CaO and CaF2 are added to the melt to improve the basicity of the slag and melt separation under heat preservation is performed to strengthen slag-metal separation.The thermodynamics of the step-by-step reduction process of TiO2 in the Ti-Al-Fe-Si-O system whose composition is close to the alloy after melt separation were calculated.Samples of alloys and slags before and after melt separation were systematically analyzed.The result indicates that the reaction that TiO is reduced by Al to Ti is the limited step in the reduction process of TiO2.The O content of the alloys slightly decreases with temperature from 1873 to 2023 K,which agrees with the changes in the law of deoxidation limit.It is mainly attributed to the movement of chemical reactions in the alloy melt at different temperatures and slag-metal interfacial reaction.The addition of Al2 O3-CaO-CaF2 slag and high temperature promote the removal of Al2 O3 and titanium suboxides.The minimum contents of O and Al in the alloy reach 1.84 wt% and 3.26 wt%,respectively.

关键词： High ferrotitanium Oxygen content melt separation Slag-metal separation Thermite method

Influence of melt spinning and annealing treatment on structures and hydrogen storage thermodynamic properties of La0.8Pr0.2MgNi3.6Co0.4 alloy

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Journal of Iron and Steel Research(International) 2020年第1期27卷 114-120页

作者： Ting-ting Zhai Ze-ming Yuan Feng Hu Long Luo Yong-zhi Li Hao Sun Dian-chen Feng Yang-huan Zhang School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China

La0.8Pr0.2MgNi3.6Co0.4 alloys were prepared by induction melting,annealing and melt spinning techniques.The influences of annealing treatment and melt spinning on phase structure and hydrogen storage properties were systematically investigated.The results of X-ray diffraction determine that the as-cast and as-spun La0.8Pr0.2MgNi3.6Co0.4 alloys consist of LaMgNi4 and LaNi5 phases,while only LaMgNi4 phase is present in the as-annealed alloy.The scanning electron microscope images illustrate that the grain of the alloy is significantly refined by melt spin ning tech no logy.The gaseous hydrogen storage kinetic and thermodynamic properties were measured by using a Sievert's apparatus at different temperatures.The maximum hydrogen storage capacity of the as-cast,as?spun and as-annealed La0.8Pr0.2MgNi3.6Co0.4 alloy is 1.699,1.637 and 1.535 wt.% at 373 K and 3 MPa,respectively.The annealed alloy has flatter and wider pressure plateaus compared with the as-cast and as-spun alloys,which correspond to the hydrogen absorption and desorption process of LaMgNi4 and corresponding hydride.Furthermore,the enthalpy and entropy changes of LaMgNi4 during hydrogenation at different temperatures were calculated using Van't Hoff methods.

关键词： Hydrogen storage Multiphase structure Annealing melt spinning Thermodynamics

A soft sensor for industrial melt index prediction based on evolutionary extreme learning machine

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Chinese Journal of Chemical Engineering 2016年第8期24卷 1013-1019页

作者： Miao Zhang Xinggao Liu Zeyin Zhang State Key Laboratory of Industrial Control Technology Department of Control Science and Engineering Zhejiang University Department of Mathematics Zhejiang University

In propylene polymerization(PP) process, the melt index(MI) is one of the most important quality variables for determining different brands of products and different grades of product quality. Accurate prediction of MI is essential for efficient and professional monitoring and control of practical PP processes. This paper presents a novel soft sensor based on extreme learning machine(ELM) and modified gravitational search algorithm(MGSA) to estimate MI from real PP process variables, where the MGSA algorithm is developed to find the best parameters of input weights and hidden biases for ELM. As the comparative basis, the models of ELM, APSO-ELM and GSAELM are also developed respectively. Based on the data from a real PP production plant, a detailed comparison of the models is carried out. The research results show the accuracy and universality of the proposed model and it can be a powerful tool for online MI prediction.

关键词： Propylene polymerization melt index prediction Extreme learning machine Gravitational search algorithm

Gaseous hydrogen storage properties of Mg-Y-Ni-Cu alloys prepared by melt spinning

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Journal of Rare Earths 2019年第7期37卷 750-759页

作者： Yanghuan Zhang Yaqin Li Wei Zhang Zeming Yuan Zhonghui Hou Yan Qi Shihai Guo Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China

For purpose of promoting the hydrogen absorption and desorption thermodynamics and kinetics properties of Mg-Ni-based alloys, partially substituting Y and Cu for Mg and Ni respectively and melt spinning technique were applied for getting Mg25-xYxNi9 Cu(χ = 0-7) alloys. Their microstructures and phases were characterized with the help of X-ray diffraction and transmission electron microscopy. Their hydrogen absorbing and desorbing properties were tested by a Sievert apparatus, DSC, and TGA, which were connected with a H2 detector. In order to estimate the dehydrogenation activation energy of alloy hydride, both Arrhenius and Kissinger methods were applied for calculation. It is found that their hydriding kinetics notably declines, however, their hydrogen desorption kinetics conspicuously improves, with spinning rate and Y content increasing. Their hydrogen desorption activation energy markedly decreases under the same constraint, and it is found that melt spinning and Y substituting Mg improve the real driving force for dehydrogenation. As for the tendency of hydrogen absorption capacity,it presents an elevation firstly and soon after a decline with the rising of spinning rate, however, it always lowers with Y content growing. With Y content and spinning rate increasing, their thermodynamic parameters(△H and △S absolute values) visibly decrease, and the starting hydrogen desorption temperatures of alloy hydrides obviously lower.

关键词： Mg-Ni-based alloy melt spinning Activation energy Hydrogen storage kinetics Thermodynamics Rare earths

Continuous melt granulation to develop high drug loaded sustained release tablet of Metformin HCl

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Asian Journal of Pharmaceutical Sciences 2017年第1期12卷 37-50页

作者： Pradnya Vaingankar Purnima Amin Department of Pharmaceutical Sciences and Technology Institute of Chemical Technology University under Section 3 of UGC Act–1956 Elite Status and Centre of Excellence–Government of Maharashtra

The present work explores the application of melt granulation technology to develop a high drug loaded sustained release matrix tablet of Metformin HCl using hydroxypropylcellulose(HPC) as a hydrophilic binder and stearic acid as an extrusion aid for producing cohesive granules. This novel approach allowed the use of a minimum number of excipients to reduce the tablet size, and to enhance compressibility of the drug. This also offered a cost effective method owing to the elimination of a ‘drying step’ prevalent in wet granulation method.Moreover, this research also focuses on resolving the processability issues associated with the use of HPC Nisso-H at high drug loading. The thermal lubricants were screened for this purpose and evaluated for their impact on extrudability, granule and tablet characteristics. Stearic acid was selected as the thermal lubricant, which not only contributed to the inhibition of burst release, but also improved the flow property of the granules.The developed matrix tablet(75% drug loading) resulted in 670 mg of weight for 500 mg dose strength and showed sustained drug release over 10 h. When compared, with conventional granulation techniques, it was observed that, under identical compression force, the tablet prepared by MG exhibited superior compactibility along with tablet hardness and optimal drug release profile. FTIR suggested nonexistence of chemical interaction between the drug and the other excipients while XRD and DSC analysis revealed the crystalline state of the drug.Furthermore, the results obtained from Raman spectroscopy proved the uniform distribution of the Metformin HCl and polymer in the final dosage form. This technology leads to the manufacture of sustained release matrix formulation with reduced tablet size of a high dose,highly water soluble drug otherwise difficult to process using standard batch-granulation.

关键词： Metformin hydrochloride Hydroxypropylcellulose High drug loaded tablet melt granulation