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An experimental approach for investigating many-body phenomena in Rydberg-interacting quantum systems

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Frontiers of physics 2014年第5期9卷 571-586页

作者： C. s. hofmann G. Gunter h. schempp N. L. m. miiller A. Faber h. Busche m. Robert-de-saint-Vincent s. Whitlock m. Weidemuller Physikalisches Institut Universitiit Heidelberg Im Neuenheimer Feld 226 69120 Heidelberg Germany Center for Free-Electron Laser science DESY Notkestrasse 85 22607 Hamburg Germany Department of Physics University of Basel Klingelbergstrasse 82 4056 Basel Switzerland Joint Quantum Centre (JQC) Durham-Newcastle Department of Physics Durham University Rochester Building South Road Durham DH1 3LE United Kingdom

Recent developments in the study of ultracold Rydberg gases demand an adwanced level of experimental sophistication, in which high atomic and optical densities.m.st be combined with excellent control of external fields and sensitive Rydberg atom detection. We describe a tailored experimental system used to produce and study Rydberg-interacting atoms excited from dense ultracold atomic gases. The experiment has been optimized for fast duty cycles using a high flux cold atom source and a three beam optical dipole trap. The latter enables tuning of the atomic density and temperature over several orders of magnitude, all the way to the Bose--Einstein condensation transition. An elec- trode structure surrounding the atoms allows for precise control over electric fields and single-particle sensitive field ionization detection of Rydberg atoms. We review two experiments which highlight the influence of strong Rydberg---Rydberg interactions on different many-body systems. First, the Rydberg blockade effect is used to pre-structure an atomic gas prior to its spontaneous evolution into an ultracold plasma. second, hybrid states of photons and atoms called dark-state polaritons are studied. By looking at the statistical distribution of Rydberg excited atoms we reveal correlations between dark-state polaritons. These experiments will ultimately provide a deeper understanding of many-body phenomena in strongly-interacting regimes, including the study of strongly-coupled plasmas and interfaces between atoms and light at the quantum level.

关键词： ultracold Rydberg gases ultracold plasmas Bose-Einstein condensation atom-light interactions many-body interactions

Raman spectroscopic study of silicon Nanopowders

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Journal of materials science & Technology 1997年第4期13卷 327-332页

作者： s.m.sch.lz J.Dutta and h.hofmann(Lab. de Technologie des Poudres, Departement de materiaux, Ecole Polytechnique Federale de Lausanne,1015 Lausanne, switzerland)h.hofmeister (max-Planck-Institut fur mikrostrukturphysik, Weinberg 2, D-06120 halle, Germany) Lab. de Téchnologie Des Poudres Département de Matériaux Ecole Polytechnique Fédérale de Lausanne 1015 Lausanne Switzerland max-Planck-Institut Für mikrostrukturphysik D-06120 Halle Weinberg 2 Germany

Vibrational properties of silicon nanopowders are discussed with reference to Raman spectroscopic measurements. The powders were produced in a low pressure rf plasma from the cluster induced agglomeration of positive ions formed during the dissociation of silane. Influence of thermal treatment and the crystallization phenomena of the powder were studied. Raman spectroscopic measurements reveal size quantization effects for the particles as well as the existence of partially ordered regions in the apparently amorphous primary particles. The crystalline and amorphous volume fraction in the material were calculated from the relative spectraI intensities. The results obtained in these experiments are consistent with the observations from recent high resolution transmission electron microscopy studies of these powders

关键词： hRTEm cm nm Raman spectroscopic study of silicon Nanopowders

Effect of replacement of soybean oil by hermetia illucens fat on performance,digestibility,cecal microbiome,liver transcriptome and liver and plasma lipidomes of broilers

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Journal of Animal science and Biotechnology 2023年第4期14卷 1466-1484页

作者： Lea schäfer sarah m.Grundmann Garima maheshwari marcus höring Gerhard Liebisch Erika most Klaus Eder Robert Ringseis Institute of Animal Nutrition and Nutrition Physiology Justus Liebig University GiessenHeinrich-Buff-Ring 26-3235392 GiessenGermany Institute of Nutritional and Food sciences Molecular Food TechnologyUniversity of BonnFriedrich-Hirzebruch-Allee 753115 BonnGermany Institute of Clinical Chemistry and Laboratory medicine University Hospital of RegensburgFranz-Josef-Strauss-Allee 1193053 RegensburgGermany.

Background In contrast to protein-rich insect meal,the feed potential of insect fat is generally less explored and knowledge about the suitability of insect fat as a fat source specifically in broiler diets is still *** view of this,the present study aimed to comprehensively investigate the effect of partial(50%) and complete replacement of soybean oil with insect fat from hermetia illucens(hI) larvae in broiler diets on performance,fat digestibility,cecal microbiome,liver transcriptome and liver and plasma ***,100 male,1-day-old Cobb 500 broilers were randomly assigned to three groups and fed three different diets with either 0(group hI-0,n cens(hI) larvae fat for 35 d.= 30),2.5%(group hI-2.5,n %(hI-5.0,n = 35) or 5.0= 35) hermetia illuResults Body weight gain,final body weight,feed intake,and feed:gain ratio during the whole period and apparent ileal digestibility coefficient for ether extract were not different between *** microbial diversity did not differ between groups and taxonomic analysis revealed differences in the abundance of only four low-abundance bacterial taxa among groups;the abundances of phylum Actinobacteriota,class Coriobacteriia,order Coriobacteriales and family Eggerthellaceae were lower in group hI-5.0 compared to group hI-2.5(P s of total and individual short-chain fatty acids in the cecal digesta were not different between the three *** transcriptomics revealed a total of 55 and 25 transcripts to be differentially expressed between groups hI-5.0 ***-0 and groups hI-2.5 ***-0,respectively(P he concentrations of most lipid classes,with the exception of phosphatidylethanolamine,phosphatidylglycerol and lysophosphatidylcholine in the liver and cholesterylester and ceramide in plasma(P he s.m.of all lipid classes were not different between *** Partial and complete replacement of soybean oil with hI larvae fat in broiler diets had no effect on gro

关键词： Broilers Cecal microbiota hermetia illucens Insect fat Liver lipidome medium-chain fatty acids

Kinetics of hydrogen peroxide quenching following UV/h_(2)O_(2)advanced oxidation by thiosulfate,bisulfite,and chlorine in drinking water treatment

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Frontiers of Environmental science & Engineering 2023年第12期17卷 59-69页

作者： Tianyi Chen Lizbeth Taylor-Edmonds susan Andrews Ron hofmann Department of Civil and mineral Engineering University of TorontoTorontoOntario M5S 1A4Canada

Residual h_(2)O_(2)from UV/h_(2)O_(2)treatment can be quenched by thiosulfate,bisulfite,and chlorine,but the kinetics of these reactions have not been reported under the full range of practical *** this study,the rates of h_(2)O_(2)quenching by these compounds were compared in different water matrices,temperatures,ph,and when using different forms of bisulfite and *** general,it was confirmed that thiosulfate would be too slow to serve as a quenching agent in most practical *** ph 7-8.5,chlorine tends to quench h_(2)O_(2)more than 20 times faster than bisulfite in the various conditions *** important observation was that in lightly-buffered water(e.g.,alkalinity of 20 mg/L as CaCO_(3)),the form of chlorine can have a large impact on quenching rate,with gaseous chlorine slowing the reaction due to its lowering of the ph,and hypochlorite having the opposite *** impacts will become less significant when water buffer capacity(i.e.,alkalinity)increases(e.g.,to 80 mg/L as CaCO_(3)).In addition,water temperature should be considered as the time required to quench h_(2)O_(2)by chlorine at 4℃is up to 3 times longer than at 20℃.

关键词： UV/h_(2)O_(2) h_(2)O_(2) quenching Chlorine type Water alkalinity Temperature

Transforming growth factor-β1 induces intestinal myofibroblast differentiation and modulates their migration

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World Journal of Gastroenterology 2009年第12期15卷 1431-1442页

作者： Julia Brenmoehl sandra Nicole miller Claudia hofmann Daniela Vogl Werner Falk Jrgen schlmerich Gerhard Rogler Department of Internal medicine Ⅰ University of Regensburg93055 Regensburg Germany Department of Internal medicine Ⅱ University of Jena07747 Jena Germany Clinic of Gastroenterology and hepatology Department of Internal MedicineUniversity Hospital of Zurich8091 ZurichSwitzerland

AIm： To investigate the effects of transforming growth factor β1 （TGF-β1） on the differentiation of colonic lamina propria fibroblasts （CLPF） into myofibroblasts in vitro.mEThODs： Primary CLPF cultures were incubated with TGF-β1 and analyzed for production of m-smooth muscle actin （α-smA）, fibronectin （FN） and FN isoforms. migration assays were performed in a modified 48-well Boyden chamber. Levels of total and phosphorylated focal adhesion kinase （FAK） in CLPF were analyzed after induction of *** not change α-smA levels, while TGF-β1 treatment for 6 d significantly increased α-sIVlA production. short term incubation （6 h） with TGF-β1 enhanced CLPF migration, while long term treatment （6 d） of CLPF with TGF-β1 reduced migration to 15%-37% compared to untreated cells. FN and FN isoform mRNA expression were increased after short term incubation with TGF-β1 （2 d） in contrast to long term incubation with TGF-β1 for 6 d. After induction of migration, TGF-β1-preincubated CLPF showed higher amounts of FN and its isoforms and lower levels of total and phosphorylated FAK than untreated cells.CONCLUsION： Long term incubation of CLPF with TGF-β1 induced differentiation into myofibroblasts with enhanced α-smA, reduced migratory potential and FAK phosphorylation, and increased FN production. In contrast, short term contact （6 h） of fibroblasts with TGF-β1 induced a dose-dependent increase of cell migration and FAK phosphorylation without induction of α-smA production.

关键词： Transforming growth factor β1 Colonicfibroblasts myofibroblasts migration Fibronectin

Correlating the electronic structure of perovskite La_(1-x)srxCoO_(3) with activity for the oxygen evolution reaction:The critical role of Co 3d hole state

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Journal of Energy Chemistry 2022年第2期31卷 637-645页

作者： Zechao shen mei Qu Jueli shi Freddy E.Oropeza Victor A.de la Peña O’shea Giulio Gorni C.m.Tian Jan P.hofmann Jun Cheng Jun Li Kelvin h.L.Zhang state Key Laboratory of Physical Chemistry of solid surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005FujianChina Photoactivated Processes Unit IMDEA Energy InstituteParque Tecnológico de MóstolesAvda.Ramón de la Sagra 328935 MóstolesMadridSpain CELLs-ALBA synchrotron Carrer de la Llum 2-2608290 Cerdanyola del VallèsSpain surface science Laboratory Department of Materials and Earth SciencesTechnical University of Darmstadt Otto-Berndt-Strasse 364287 DarmstadtGermany

Perovskite LaCoO_(3) is being increasingly explored as an effective low-cost electrocatalyst for the oxygen evolution reaction(OER).sr doping in LaCoO_(3)(La1-xsrxCoO_(3))has been found to substantially increase its catalytic *** this work,we report a detailed study on the evolution of the electronic structure of La1-xsrxCoO_(3) with 0≤x≤1 and its correlation with electrocatalytic activity for the OER.A combination of X-ray photoemission spectroscopy(XPs)and X-ray absorption spectroscopy(XAs)was used to unravel the electronic density of states(DOs)near the Fermi level(EF),which provide insights into the key electronic structure features for the enhanced OER catalytic *** analysis on the Co L-edge XAs suggest that LaCoO_(3) has a low spin state with t_(2g)^(6) e_(g)^(0) configuration at room *** implies that the high OER catalytic activity of LaCoO_(3) should not be rationalized by the occupancy of eg=1 *** sr^(2+) for La^(3+) in LaCoO_(3) induces Co4+oxidation states and effectively dopes hole states into the top of valence band.A s.m.conductor-to-metal transition is observed for x>0.2,due to the holeinduced electronic DOs at the EF and increased hybridization between Co 3 d and O 2 *** an electronic modulation enhances the surface adsorption of the*Oh intermediate and reduces the energy barrier for interfacial charge transfer,thus improving the OER catalytic activity in La_(1-x)sr_(x)CoO_(3).In addition,we found that the La_(1-x)sr_(x)CoO_(3) surface undergoes amorphization after certain period of OER measurement,leading to a partial deactivation of the *** sr doping levels accelerated the amorphization process.

关键词： Perovskite oxide Oxygen evolution Cobalt Electronic structure

Reactive destabilization and bidirectional catalyzation for reversible hydrogen storage of LiBh_(4) by novel waxberry-like nano-additive ass.m.led from ultrafine Fe_(3)O_(4) particles

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Journal of materials science & Technology 2024年第6期173卷 63-71页

作者： s.Wang m.h.Wu Y.Y.Zhu Z.L.Li Y.X.Yang Y.Z.Li h.F.Liu m.X.Gao Department of material science Shenzhen MSU-BIT UniversityShenzhen 518172China state Key Laboratory of silicon and Advanced s.m.conductor materials&school of materials science and Engineering Zhejiang UniversityHangzhou 310027China Institute of Resources Utilization and Rare Earth Development State Key Laboratory of Rare Metals Separation and Comprehensive UtilizationGuangdong Provincial Key Laboratory of Rare Earth Development and ApplicationGuangdong Academy of SciencesGuangzhou 510650China Institute of science and Technology for New Energy Xi’an Technological UniversityXi’an 710021China National supercomputing Center in shenzhen Shenzhen 518055China

LiBh_(4) containing 18.5 wt.%h_(2) is an attractive high-capacity hydrogen storage material,however,it suffers from high operation temperature and poor ***,a novel and low-cost bifunctional additive,waxberry-like Fe_(3)O_(4) secondary nanospheres ass.m.led from ultrafine primary Fe_(3)O_(4) nanoparticles,is synthesized,which exhibits significant destabilization and bidirectional catalyzation towards(de)hydrogenation of LiBh_(4).With an optimized addition of 30 wt.% waxberry-like Fe_(3)O_(4),the system initiated dehydrogenation below 100℃ and released a total of 8.1 wt.%h_(2) to 400℃.After 10 cycles,a capacity retention of 70% was achieved,greatly superior to previously reported oxides.m.dified *** destabilizing and catalyzing mechanisms of waxberry-like Fe_(3)O_(4) on LiBh_(4) were systematically analyzed by phase and microstructural evolutions during dehydrogenation and hydrogenation cycling as well as density functional theory(DFT)*** present work provides new insights in developing advanced nano-additives with unique structural and multifunctional designs towards LiBh4 hydrogen storage.

关键词： LiBh_(4) hydrogen storage Waxberry-like Fe_(3)O_(4) Destabilization Catalysis

ImPROVEmENT OF CARBIDE mORPhOLOGY ANDmEChANICAL PROPERTIEs OF Cr12moV sTEELs

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Acta metallurgica sinica(English Letters) 2000年第5期13卷 1053-1058页

作者： Cui, X.h. Jiang, Q.C. Wang, s.Q. he, Z.m. sch. of mat. sci. and Eng. Jilin Univ. of Technol. Changchun 130025 China

Compared with conventional cast Cr12moV steel and forged Cr12moV steels, carbide morphology and properties of modified cast Cr12moV steels were investigated by performing hardness test, impact test, fracture toughness test, fatigue crack propagation test, metallographic examination and quantitatively metallographic analysis. The results indicate that the carbide morphology in modified cast steel is characterized by uniformly-distributed granular carbide, which is different from that of conventional cast steel, but s.m.lar to that of forged steel. the impact toughness of modified cast steel is distinctly increased to 12.75 J/cm2 from 6.8 J/cm2 in the conventional cast steel with networked carbide, because of carbide granulation. Furthermore, The fracture toughness and fatigue-crack-propagation threshold of modified cast steel are not only higher than that of the conventional cast steel, but also higher than that of the forged steels.

关键词： Alloys Carbides mechanical properties morphology

Preparation and Properties of s.m. Chemical and Electrochemical γ-mnO_2

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Journal of materials science & Technology 2001年第3期17卷 351-354页

作者： h.m.Abbas, Kh. s.Abou-El-sherbini, m.h.Askar and A. m. hashim Dept.of Physical Centre, National Research Centre, Tahiu, Dokki, Cairo, Egypt E-mail: sherbini@*** Natl Res Ctr Dept Phys Ctr Cairo Egypt

Chemically prepared electrolytic 2-mn02 and an electrodeposited mnO2 doped with Ce(Ⅲ) were subjected to physicochemical studies. X-ray diffractometry, density measurements, chem-ical analysis and thermal analysis were used to determine the structure and chemical disorder present. The s.m.les prepared chemically (CmD) or electrochemically (EmD) showed a variable amount of de Wolff disorder (Pr) and microtwinning (Tw). manganese dioxide prepared in the presence of Ce(Ⅲ) showed appreciable decrease in de Wolff defect and a large amount of microtwinning. Thermal analysis showed a loss of weight due to the physically adsorbed and the structural (Oh) water, from which the activation energy was calculated. Chemical composition and formulae calculated on the bases of cation vacancy model, cleared that Ce(lIl)-doped s.m.le has a remarkable increase in the vacancies population associated with higher structural water content. This leads to lower activation energy of water release, and consequently it is supposed to acquire higher electrochemical activity.

关键词： EmD mnO2