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Promotion effect of sulfur impurity in alumina support on propane dehydrogenation

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Journal of Energy Chemistry 2022年第7期31卷 332-339,I0009页

作者： Xin-Qian Gao Wen-Cui Li Bin Qiu Jian Sheng Fan Wu An-Hui Lu State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian 116024LiaoningChina

Alumina materials are widely applied either as a catalyst or support in various industrial catalytic processes. Impurities in alumina that are unfriendly to catalytic performance are inevitably present during the production processes. Facing this problem, we here report that the use of sulfur-containing alumina as the support can generate active alumina-supported platinum catalyst, which exhibits superior propylene selectivity and anti-coking ability during propane dehydrogenation. It demonstrated that the sulfur impurity in alumina is not entirely detrimental. During the reduction process, the formation of gas-phase sulfur species increased the electrons and poisoned unsaturated sites of platinum particles. The sulfur impurity in alumina can be removed through a hydrogen reduction process, and the degree of desulfurization is correlated with the operating temperature. This study demonstrated that the rational use of impurity will contribute to the design of a catalyst with high reactivity for potential applications.

关键词： Alumina impurity Sulfur Platinum Propane dehydrogenation

impurity Effect on Wear Resistance of Ultrafine-Grained Copper

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Journal of Materials Science & Technology 2012年第6期28卷 481-487页

作者： Bin Yao Zhong Han Ke Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The wear properties of ultrafine-grained （UFG） Cu samples of different purities were investigated in comparison with the coarse-grained （CG） Cu. The UFG Cu samples, prepared by means of plastic deformation via quasi- static compression, exhibit an enhanced wear resistance relative to the CG Cu samples. For both the UFG and the CG Cu samples, wear volumes increase at higher purities. A steady state worn subsurface structure was formed in each sample after sliding for 60 rain, consisting of a heavily deformed nanostructured mixing layer （NML） on top of a continuous dynamic recrystallization （DRX） layer. A pronounced correlation is identified that wear volume increases monotonically with an increasing grain size of the DRX layer. The impurity level of the Cu samples has an obvious influence on the DRX grain sizes, which in turn determines the wear resistance of the Cu samples.

关键词： Ultrafine grained copper Wear resistance impurity Subsurface microstructure Dynamic recrystallization

impurity-induced local modes in one-dimensional dusty plasma chains

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Chinese Physics B 2012年第11期21卷 321-326页

作者：任永超王欣上王晓钢 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking University

The effects of impurity on eigenmodes in one-dimensional dusty plasma lattices are studied. It is found that local modes can be excited besides lattice waves, due to the existence of an impurity particle. The dispersion relations of the modes are derived accordingly. Properties of the lattice and local modes are also analyzed and discussed, particularly for their symmetric features and conditions of the mode excitation.

关键词： impurity local mode dusty plasma

impurity Measurement and Study on HL-2A Divertor Tokamak

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Plasma Science and Technology 2006年第1期8卷 61-64页

作者：崔正英孙平潘宇东李伟王全明段旭如 Southwestern Institute of Physics Chengdu 610041China

HL-2A tokamak with two close divertors has been operated since 2003. In the experimental campaign of 2004 the divertor configuration has been successfully formed and the sillconization as a wall conditioning has been firstly done in this device. The divertor configuration can be reconstructed by the CFc code. impurity behavior has been investigated during the experiment with divertor configuration and wall conditioning. The reduction of impurity is clear under both conditions of divertor configuration and siliconization.

关键词： plasma wall conditioning impurity

impurity Measured by VUV Spectrometer and OMA on HL-2A Tokamak

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Plasma Science and Technology 2004年第4期6卷 2359-2363页

作者：崔正英王全明董贾福孙平卢杰李伟王恩耀 SouthwesternInstituteofPhysics Chengdu610041China

impurity is one of the key issues on a great impact to the quality of tokamak plasma. HL-2A is the first divertor tokamak in China. In this paper the experimental results are presented on impurity through the line emission measurement in the campaign in 2003 under the limiter and divertor configurations. The low-Z impurities such as carbon and oxygen are the most important components in the plasma, but their content are not so high to affect the discharge quality. The high-Z impurities such as copper and ferrum are not essential. The emission intensity of impurity is clearly decreased during the divertor configuration formed.

关键词： limiter line emission impurity divertor

Micro-alloyed Mg-Ca:Corrosion susceptibility to heating history and a plain problem-solving approach

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Journal of Magnesium and Alloys 2023年第4期11卷 1193-1205页

作者： Min Deng Linqian Wang Darya Snihirova Jan Bohlen Gerrit Kurz Sviatlana V.Lamaka Daniel Höche Mikhail L.Zheludkevich Institute of Surface Science Helmholtz-Zentrum HereonMax-Planck Str.1Geesthacht 21502Germany Institute of Material and Process Design Helmholtz-Zentrum HereonGeesthacht 21502Germany Institute of Materials Science Faculty of EngineeringKiel UniversityKiel 24143Germany

The exceptionally low corrosion rate(∼0.1 mm y^(–1)in concentrated NaCl solution for 7 days)enables lean Mg-Ca alloys great potential for diverse applications,particularly if relevant properties(e.***.mechanical strength,electrochemical performance,etc.)can be enhanced by thermomechanical processing.However,herein it is demonstrated that the corrosion performance of lean Mg-Ca is susceptible to the heating process.The corrosion rate of Mg-0.15 wt%Ca alloy is remarkably accelerated after annealing even for a short time(4 h at 400℃)because Fe precipitation readily takes place.Fortunately,it is found that micro-alloying with dedicated additional elements is able to solve this problem.Nevertheless,the problem-solving capability is dependent on the element category,particularly the ability of the alloying element to constrain the Fe precipitation.Among the three studied elements(i.e.Sn,Ge and In),only In shows good competence of restricting the formation of Fe-containing precipitates,thereby contributing to retention of the superior corrosion resistance after annealing even at a rigorous condition(24 h at 450℃).The finding creates good foundation for follow-up work of developing lean Mg-Ca-based alloys combining high corrosion resistance,superior electrochemical performance with excellent mechanical properties for applications as biodegradable implants and anode materials for aqueous batteries.

关键词： Magnesium Micro-alloying Thermomechanical processing Corrosion impurity

Characterizations on the instantaneously formed Ni-containing intermetallics in magnesium alloys

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Journal of Magnesium and Alloys 2023年第8期11卷 2991-2998页

作者： Shuhui Lv Qiang Yang Fanzhi Meng Jian Meng School of Materials Science and Engineering Changchun University of Science and Technology 130022PR China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022PR China

Instantaneous reactions of Al,Mn,Zn,Zr and Y with Ni by mixing the prepared Mg-8Al-0.4Mn,Mg-6Zn-2Y-0.5Zr and Mg-0.6Ni melts were investigated in this work to reveal the underlying mechanisms of their effects on the removal of Ni impurity.The results indicate three Ni-containing intermetallics,namely Al_(4)NiY,Al_(4)Ni(Y,Zr)and Al_(31)Ni_(2)Mn_(6).The former two phases present lath-like and have a relatively larger size(>20μm in length)than the latest one which is granular with the diameter of∼120 nm.This illustrates that Al and Y(/Zr)can efficiently remove Ni by forming Al_(4)NiY or Al_(4)Ni(Y,Zr)which would precipitate to the bottom of the melt.Furthermore,adding Y into Mg-Al based alloys can simultaneously remove Fe and Ni,which contributes their excellent corrosion resistance.Finally,this paper proposes two methods helped to efficiently remove Ni for both Mg-Al based alloys and Al-free Mg alloys,and both of them are also benefit to improve alloys’strength.

关键词： Magnesium alloys Intermetallics Nickel Transmission electron microscopy(TEM) impurity

Prospects to the formation and control of potential dimer impurity E of pantoprazole sodium sesquihydrate

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Journal of Pharmaceutical Analysis 2019年第3期9卷 170-177页

作者： Arun Kumar Awasthi Lalit Kumar Punit Tripathi Madhava Golla Cirandur Suresh Reddy Pramod Kumar Micro Labs Ltd. Chemical Research Department API R&D Centre Plot No. 43-45 KIADB IVth Phase Bommasandra-Jigani Link Road Anekal Taluk Bangalore 560105 Karnataka India Department of Chemistry Sri Venkateswara University Tirupati 517502 Andhra Pradesh India

Pantoprazole sodium, a substituted benzimidazole derivative, is an irreversible proton pump inhibitor which is primarily used for the treatment of duodenal ulcers, gastric ulcers, and gastroesophageal reflux disease (GERD). The monographs of European Pharmacopoeia (Ph. Eur.) and United States Pharmacopoeia (USP) specify six impurities, viz.;impurities A, B, C, D, E and F, respectively for its active pharmaceutical ingredient (API). The identification and synthesis of all impurities except impurity E are well described in the literature;however, there is no report related to impurity E. The prospects to the formation and controlling of impurity E up to -0.03% in the synthesis of pantoprazole sodium sesquihydrate (PAN) were discussed in detail for the first time. The present work described the journey towards the successful development of an optimal preparation procedure of dimer impurity E. The most plausible mechanism involved in the formation of impurity E has been proposed.

关键词： Pantoprazole sodium sesquihydrate impurity E Oxidation Enrichment Column chromatography Characterization HPLC

Local charge neutrality condition,Fermi level and majority carrier density of a semiconductor with multiple localized multi-level intrinsic/impurity defects

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Journal of Semiconductors 2011年第11期32卷 1-8页

作者： Ken K.Chin Department of Physics and Apollo CdTe Solar Energy Research Center New Jersey Institute of Technology Department of Photonic and Information Engineering School of Electronic and Information EngineeringBeihang University

For semiconductors with localized intrinsic/impurity defects, intentionally doped or unintentionally incorporated, that have multiple transition energy levels among charge states, the general formulation of the local charge neutrality condition is given for the determination of the Fermi level and the majority carrier density. A graphical method is used to illustrate the solution of the problem. Relations among the transition energy levels of the multi-level defect are derived using the graphical method. Numerical examples are given for p-doping of the CdTe thin film used in solar panels and semi-insulating Si to illustrate the relevance and importance of the issues discussed in this work.

关键词： multi-level defects defect complex intrinsic impurity semiconductor Fermi level majority carrier density