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Preparation and investigation of Pd doped Cu catalysts for selective hydrogenation of acetylene

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Frontiers of Chemical Science and Engineering 2020年第4期14卷 522-533页

作者： Xinxiang Cao Tengteng Lyu Wentao Xie Arash Mirjalili Adelaide Bradicich ricky Huitema Ben W.-L.Jang Jong k.keum karren more Changjun Liu Xiaoliang Yan Department of Chemistry Texas A&M University-CommerceCommerceTX 75429-3011.USA Laboratory for Development&Application of Cold Plasma Technology College of Chemistry and Chemical EngineeringLuoyang Normnal UniversityLuoyang 471022China Collaborative Innovation Center of Chemical Science and Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Center for Nanophase Materials Sciences and Chemical Science Division Oak Ridge National LaboratoryOak RidgeTN 37831USA College of Chemistry and Chemical Engineering Taiyuan University of TechnologyTaiyuan 030024China

A series of PdCu bimetallic catalysts with low Cu and Pd loadings and different Cu:Pd atomic ratios were prepared by conventionally sequential impregnation(CSD)and modified sequential impregnation(MSI)of Cu and Pd for selective hydrogenation of *** indicates that the supported copper(I)nitrate in the PdCu bimetallic catalysts prepared by MSI can be directly reduced to Cu metal particles due to the hydrogen spillover from Pd to Cu(NO3)2 *** addition,for the catalysts prepared by MSI,Pd atoms can form PdCu alloy on the surface of metal particles,however,for the catalysts prepared by CSI,Pd tends to migrate and exist below the surface layer of *** results indicate that compared with CSI,the MSI method enables samples to possess preferable stability as well as comparable reaction *** should be due to the MSI method in favor of the formation of PdCu alloy on the surface of metal ***,even Pd loading is super low,rough adjusting Cu loading to an appropriate value,attractive reactivity and selectivity still can be achieved.

关键词： copper palladium catalysts acetylene selec-tive hydrogenation

Advancement in utilization of magnetic resonance imaging and biomarkers in the understanding of schizophrenia

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World Journal of Clinical Cases 2025年第1期13卷 11-15页

作者： Aidan k Tirpack Danyaal G Buttar Mandeep kaur Department of Psychiatry Campbell University School of Osteopathic MedicineBuies CreekNC 27506United States Department of Psychiatry and Behavioral Health Mercyhealth Hospital and Trauma CenterJanesvilleWI 53548United States

Historically,psychiatric diagnoses have been made based on patient’s reported symptoms applying the criteria from diagnostic and statistical manual of mental *** utilization of neuroimaging or biomarkers to make the diagnosis and manage psychiatric disorders remains a distant *** have been several studies that examine brain imaging in psychiatric disorders,but more work is needed to elucidate the complexities of the human *** this editorial,we examine two articles by Xu et al and Stoyanov et al,that show developments in the direction of using neuroimaging to examine the brains of people with schizo-phrenia and *** et al used magnetic resonance imaging to examine the brain structure of patients with schizophrenia,in addition to examining neurotransmitter levels as *** et al used functional magnetic resonance imaging to look at modulation of different neural circuits by diagnostic-specific scales in patients with schizophrenia and *** two studies provide crucial evidence in advancing our understanding of the brain in prevalent psychiatric disorders.

关键词： Schizophrenia Magnetic resonance imaging Biomarkers Neurotransmitters Psychiatric disorders

Photolysis studies on HCOOH and HCOO^- in presence of TiO_2 photocatalyst as suspension in aqueous medium

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Journal of Natural Gas Chemistry 2009年第1期18卷 50-54页

作者： G. r. Dey k. N. r. Nair k. k. Pushpa radiation and Photochemistry Division Bhabha Atomic Research Centre Trombay Mumbai 400 085 India

Photolysis studies on formic acid （HCOOH） and formate ion （HCOO-） in presence of TiO2, a photocatalyst, as suspension in water were carried out separately using 350 nm ultraviolet light. The products, such as H2, CO, CO2 and CH4, generated during the experiments were monitored with varying the ambient, light exposure time, and the concentration of HCOOH/HCOO-. The yields of CO in all these systems increased with light exposure time. In aerated systems, CO yields were higher in contrast to the deoxygenated （Ar-purged） systems under identical conditions. It is proposed apparently that the formation of CO is taking place during the chemical reduction of in-situ generated CO2, a photo-mineralized product of HCOOH/HCOO-, but not through the direct photodecomposition or photodehydration （CO＋H2O） of solute molecules. The rates of CO formation during 1.3 M HCOOH photolysis in presence of TiO2 photocatalyst were evaluated to be 0.21 and 0.13 μl/min in aerated and Ar-purged systems, respectively. As compared with HCOOH systems, the CO yields are lower when 0.2 M HCOONa was exposed to light under identical conditions. The CO growth rates were evaluated to be 0.07 and 0.046 μl/min^-1 for aerated and deoxygenated HCOONa systems, respectively; moreover, the trend is quite similar to that of the HCOOH system. Under these conditions, the emission of H2 was also observed, and its yield was significantly higher in Ar-purged system as compared with the CO yields. However, in aerated system, the yields of these products were just opposite. The formation of low yield of methane was observed during photolysis of HCOOH/HCOO ions. In CO2 ambient, the yields of CO and H2 varied drastically with time.

关键词： formic acid formate ion photolysis TiO2

On the Urbach's formula for evaluation of electron trapping parameter:The case of persistent luminescent materials

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Journal of rare Earths 2017年第8期35卷 733-738页

作者： Ngangbam Chandrasekhar k.Bishal Singh r.k.Gartia Department of Physics Manipur University Imphal-795003 Manipur India

Urbach’s formula for evaluation of electron trapping parameter that happens to be the earliest has emerged as a popular method amongst researchers of persistent luminescence. In this study, we analysed the thermoluminescence curves of glow-in-the-dark phosphors. Those included some curves recorded by us and others that solely used the Urbach’s formula. Using the parameter obtained by rigorous analysis by fitting the whole TL curves, we presented a comprehensive picture of the potentialities and limitations of the simple Urbach’s relation E=T_m/500, where E is the trap-depth and T_m the peak temperature in absolute scale, first proposed by Urbach in 1930. Some simple thumb rules on the use of the formula were presented for beginners as well as non-specialists so that entry of physically unrealistic data into the literature was prevented.

关键词： Urbach’s formula electron-trapping parameter glow-in-the-dark phosphor afterglow rare earths

Study of a collisionless magnetized plasma sheath with nonextensively distributed species

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Plasma Science and Technology 2023年第12期25卷 14-23页

作者： r PAUL k DEkA G SHArMA r MOULICk S ADHIkArI S S kAUSIk B k SAIkIA Centre of Plasma Physics Institute for Plasma ResearchAssam 782402India Institute for Energy Technology Instituttveien 8Kjeller 2007Norway

A weakly magnetized sheath for a collisionless, electronegative plasma comprising positive ions,electrons, and negative ions is investigated numerically using the fluid approach. The electrons are considered to be non-Maxwellian in nature and are described by Tsalli's distribution. Such electrons have a substantial effect on the sheath properties. The study also reveals that non-Maxwellian distribution is the most realistic description for negative ions in the presence of an oblique magnetic field. In addition to the negative ion temperature, the sheath potential is also affected by the nonextensive parameters. The present research finds application in the plasma processing and semiconductor industry as well as in space plasmas.

关键词： magnetised plasma sheath electronegative plasma non-extensive distribution

Improvement of Deep Groove Ball Bearing’s Performance Using a Bionic Textured Inner race

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Journal of Bionic Engineering 2021年第4期18卷 974-990页

作者： k.E.Ch.Vidyasagar r.k.Pandey Dinesh kalyanasundaram Center for Biomedical Engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical Engineering College of EngineeringOsmania UniversityHyderabad500007India Department of Mechanical Engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical Engineering All India Institute of Medical SciencesNew Delhi110029India

Micro-textured surfaces have improved the tribological performance of contact surfaces under lubricated conditions;however,not practiced due to manufacturing *** addition to simpler micro-pits or straight-trench type textures,sophisticated bioinspired textures on commercial radial ball bearings have been scarcely *** this work,Dendroaspis polylepis(Mamba snake)skin-type textures were fabricated on the inner race of FAG radial ball bearings using a nanosecond fiber laser *** the snake textures were primarily meant to enhance friction,the dimensions of the texture have been carefully chosen to improve the tribological performance under lubricated *** textured bearings were assembled and experimented at various rotational speeds and lightly loaded conditions to measure vibrational amplitude,frictional torque,and temperature *** to untextured(conventional)bearing,the snake-skin type textured bearings resulted in improved tribo-dynamic performance.

关键词： bionic texture radial ball bearing frictional torque vibration temperature

An exploration of frictional and vibrational behaviors of textured deep groove ball bearing in the vicinity of requisite minimum load

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Friction 2021年第6期9卷 1749-1765页

作者： k.E.Ch.VIDYASAGAr r.k.PANDEY Dinesh kALYANASUNDArAM Center for Biomedical Engineering Indian Institute of Technology DelhiNew Delhi 110016India Department of Biomedical Engineering College of EngineeringOsmania UniversityTelangana 500007India Department of Mechanical Engineering Indian Institute of Technology DelhiNew Delhi 110016India Department of Biomedical Engineering Indian Institute of Technology DelhiNew Delhi 110016India

In case of lightly loaded radial ball bearings,failure mechanisms other than fatigue such as smearing of raceways due to increased frictional torque and vibrations often ***,attempts have been made herein for reducing the frictional torque and minimizing the vibrations of a radial deep groove ball bearing employing surface textures at the inner *** pulsed laser was used to create texture(involving micro-dimples having different dimple area density)on the inner race of test *** an in-house developed test rig,frictional torque and vibrational parameters were measured at different speeds and light loads(*** vicinity of 0.01C,where C is dynamic load capacity of radial ball bearing).Significant reduction in frictional torque and overall vibrations were found in the presence of micro-dimples on inner race at light loads irrespective of operating *** without satisfying the minimum load needed criteria for the satisfactory operation,substantial reduction in smearing marks was found on the races of textured ball bearings in comparison to conventional cases.

关键词： ball bearing textured inner race grease lubricated frictional torque vibration

Non Existence of Shear in Bianchi Type-ⅢString Cosmological Models with Bulk Viscosity and Time-Dependent A Term

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Chinese Physics Letters 2011年第2期28卷 55-57页

作者： r.k.Tiwari Sonia Sharma Department of Mathematics Govt.Model Science CollegeRewa(MP)India Department of Mathematics Rayat Polytechnic CollegeRopar(Punjab)India

We study the non existence of shear in locally rotationally symmetric Bianchi type-Ⅲstring cosmological models with bulk viscosity and variable cosmological termΛ.Exact solutions of the field equations are obtained by assuming the conditions:the bulk viscosity is proportional to the expansion scalar,ξ∝θ,expansion scalar is proportional to shear scalar,θ∝σ,and A is proportional to the Hubble *** coefficient of bulk viscosity is assumed to be a power function of mass *** corresponding physical interpretations of the cosmological solutions are also discussed.

关键词： parameter density viscosity

Anisotropic Bianchi Type-ⅠModel with a Varying A Term

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Chinese Physics Letters 2012年第3期29卷 41-43页

作者： r.k.Tiwari Divya Singh Department of Mathematics Govt.Model Science College RewaM.P.486001India

Einstein field equations with variable gravitational and cosmological constants are considered in the presence of a perfect fluid for a Bianchi type-I universe by assuming that the cosmological term is proportional to the Hubble parameter..The variation law for vacuum density was recently proposed by Schützhold on the basis of quantum field estimation in a curved expanding *** cosmological term tends asymptotically to a genuine cosmological constant and the model tends to a de Sitter *** obtain that the present universe is accelerating with a large fraction of cosmological density in the form of a cosmological term.

关键词： universe parameter gravitational