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dielectric and infrared properties of SrTiO_3 single crystal doped by 3d (V,Mn,Fe,Ni) and 4f (Nd,Sm,Er) ions

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Chinese Physics B 2014年第2期23卷 369-374页

作者： S.Maletic d.Maletic I.Petronijevic J.dojcilovic d.M.Popovic Faculty of Physics University of Belgrade Institute of Physics University of Belgrade

In this study, the effects of doping by 3d （V, Mn, Fe, Ni） and 4f （Nd, Sm, Er） ions on dielectric and infrared properties of SrTiO3 （STO） single crystals are investigated. It is well known that doping of the SrTiO3 can change the dielectric properties of the STO from an insulator to an n-type semiconductor, and even to a metallic conductor. dielectric and infrared （IR） properties of the undoped STO and doped STO single crystals are analyzed using dielectric spectroscopy （80 kHz-5 MHz）, transmission （200 cm^-1-4000 cm^-1）, and reflection spectroscopy （50 cm^-1-2000 cm^-1）. It is found that doping by the 3d ions reduces the value of dielectric permittivity, but the trend of temperature dependence of the dielectric permittivity remains almost unchanged. On the other hand, dielectric spectroscopy measurements for samples doped by 4f ions show the anomalous behaviors of the dielectric permittivity at temperatures around the temperature of the structural phase transition. There are two fractures of temperature dependences of inverse dielectric permittivity εr^-1 （T）. Transmittance spectroscopy measurements show that there are differences in the shape of the spectrum in the mid-IR region between the undoped STO and the one doped by 4f ions. The differences in the reflectance spectrum between the STO：Nd.a.d STO are analyzed in detail.

关键词： doping dielectric properties phase transitions infrared spectroscopy

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and.a.onal fusion

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Neural Regeneration Research 2025年第4期20卷 1192-1206页

作者： Tyler A.Smith Liwen Zhou Cameron L.Ghergherehchi Michelle Mikesh Cathy Z.Yang Haley O.Tucker JuliAnne Allgood Jared S.Bushman George d.Bittner department of Molecular Biosciences University of Texas at AustinAustinTXUSA department of Neuroscience University of Texas at AustinAustinTXUSA division of Pharmaceutical Sciences University of WyomingLaramieWYUSA

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal ***,such peripheral nerve allografts undergo immunological rejection by the host immune *** contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian *** relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this *** hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral *** examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced.a.onal ***-type sciatic nerve injuries in outbred Sprague–dawley rats were repaired.a.cording to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host *** to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-med.a.ed behavioral functions by 42 days *** morphological signs of rejection,such as col

关键词： allograft rejection axotomy macrophage myelin nerve repair polyethylene glycol(PEG) sciatic nerve T cell transplantation Wallerian degeneration

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毫秒脉冲星PSR1257+12的行星系统

北京大学学报（自然科学版） 2002年第B12期38卷 82-88,140-141页

作者： A.沃斯赞 d.a.弗雷尔吴鑫基美国国家天文和电离层中心阿雷西博天文台美国国家射电天文台

Making the link between AdF and 4d STEM:Resolution,transfer and coherence

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Chinese Physics B 2024年第11期33卷 26-33页

作者： Peter d.Nellist Timothy J.Pennycook department of Materials University of OxfordOxfordUK EMAT University of AntwerpGroenenborgerlaan 1712020 AntwerpBelgium

Steve Pennycook is a pioneer in the application of high-resolution scanning transmission electron microscopy(STEM)and in particular the use of annular dark-field.a.F)*** we show how a general framework for 4d STEM allows clear links to be made between AdF imaging and the emerging methods for reconstructing images from 4d STEM data *** show that both AdF imaging and ptychographical reconstruction can be thought of in terms of integrating over the overlap regions of diffracted discs in the detector *** approach allows the similarities in parts of their transfer functions to be understood,though we note that the transfer functions for ptychographic imaging cannot be used.a. a measure of information *** also show that conditions of partial spatial and temporal coherence affect AdF imaging and ptychography similarly,showing that achromatic interference can always contribute to the image in both cases,leading to a robustness to partial temporal coherence that has enabled high-resolution imaging.

关键词： image forming and processing phase retrieval electron microscopy scanning transmission electron microscope(STEM)

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关于南雄盆地K/T界线地层序列的几个问题

古脊椎动物学报 1993年第2期31卷 139-145页

作者： d.a.拉塞尔 d.E.拉塞尔 A.R.斯威特胡耀明加拿大自然博物馆研究部法国国家自然历史博物馆古生物研究所加拿大地质调查所沉积学和石油地质研究院

中国南部南雄盆地含K/T界线的陆相沉积是很宝贵的地史资料。因为迄今为止,除北美西部以外,含K/T界线的陆相露头研究得很少,赵资奎等(1991)提供了有关南雄盆地K/T界线的丰富资料。我们尝试着对其中一些资料作不同的解释,以鼓励在南雄工... 详细信息

中国南部南雄盆地含K/T界线的陆相沉积是很宝贵的地史资料。因为迄今为止,除北美西部以外,含K/T界线的陆相露头研究得很少,赵资奎等(1991)提供了有关南雄盆地K/T界线的丰富资料。我们尝试着对其中一些资料作不同的解释,以鼓励在南雄工作的同行。南雄地层的年代测定对研究该地的K/T界线至关重要。园圃组上段所含喷发玄武岩的平均年龄为67.4ma(赵资奎等,1991),属于晚Maestrichtian期,大约与31正向磁极性带的顶部同时。如果31N带在该地全部保存的话,园圃组上段的沉积速率将为70m/ma(见表Ⅰ)。上覆坪岭组厚约161m,赵资奎等(1991)认为其下段33m所含的正向磁极性带是30N,如果该带在这里全部保存,这一段的沉积速率将是19.3m/ma,这和加拿大西部含K/T界线地层的沉积速率接近。赵资奎等(1991)认为坪岭组上段微量元素富集带的底界在K/T界线下120m处。

关键词：南雄盆地 K/T界线地层

Effect of p-d exchange with an itinerant carrier in a GaMnAs quantum dot

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Journal of Semiconductors 2013年第7期34卷 1-6页

作者： d.Lalitha A.John Peter department of Physics GTN College department of Physics Government Arts College

Hydrogenic acceptor binding energy as a function of dot radius in a GaMnAs/Ga_（0.6）Al_（0.4）As quantum dot is calculated including the exchange interaction of Mn alloy content with an itinerant *** are performed by varying its dot radius,for various Mn alloy contents in GaMnAs quantum dot within a single band effective mass approximation using variational *** spin polaronic energy of the acceptor impurity for different Mn^（2＋） is evaluated for different dot radii using a mean field theory in the presence of magnetic field *** magnetization is computed in the influence of magnetic field.a.d the Mn *** effective g-factor of the valence band electron with the inclusion of effects of Mn ion impurities is found in the influence of the magnetic *** exchange coupling constant is calculated for various magnetic field *** results show that the p-d exchange interaction in the GaMnAs/Ga_（0.6）Al_（0.4）As quantum dot has a strong dependence on spatial confinement,effect of magnetic field strength and the Mn alloy *** results are in good.a.reement with the other investigators.

关键词： quantum dot acceptor diluted magnetic semiconductors

Evaluation of the WEPP Model in a Belgian Agricultural Watershed

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Journal of Environmental Science and Engineering 2011年第2期5卷 184-198页

作者： G. Govers F. Licciardello d.a. Zema S.M. Zimbone Physical and Regional Geography Research Group Katholieke University Leuven 3000 Belgium University of Catania Department of Agricultural Engineering Catania 95123 Italy department of Agro-Forest and Environmental Sciences and Technology Mediterranean University of Reggio Calabria Reggio Calabria 89122 Italy

The physically based WEPP （Water Erosion Prediction Project） model was implemented in a small agricultural watershed located in central Belgium, called Ganspoel. The watershed, mainly agricultural and resulting in a smooth topography, covers about 115 ha in a landscape typical of large parts of central Europe. Seventeen runoff, peak flow and sediment yield events, collected during a 2-year monitoring period, were simulated by the model. Even though the runoff volume predictions were well correlated to the corresponding observations, WEPP prediction capability was generally unsatisfactory also when different set-up methods of the soil effective hyd.a.lic conductivity were used. The poor performance achieved for runoff volume and peak flow simulations affected sediment yield predictions. The differences between observed.a.d simulated values for runoff, peak flow and sediment yield events may depend on： i） the great number of small runoff and sediment yield events within the available database with which is associated large natural variation and which in many cases are not well reproduced by WEPP; ii） the lack of model calibration processes; iii） the scarceness of information about some important soil physical and hydrological parameters; iv） the land use heterogeneity and crop schedule complexity of the Ganspoel watershed.

关键词： Watershed modelling WEPP water runoff peak flow soil erosion.

Additive neurorestorative effects of exercise and docosahexaenoic acid intake in a mouse model of Parkinson’s disease

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Neural Regeneration Research 2025年第2期20卷 574-586页

作者： Olivier Kerdiles Méryl-Farelle Oye Mintsa Mi-mba Katherine Coulombe Cyntia Tremblay VincentÉmond Martine Saint-Pierre Clémence Rouxel Line Berthiaume Pierre Julien Francesca Cicchetti Frédéric Calon Facultéde pharmacie UniversitéLaval1050 Avenue de la MédecineQuebecQCCanada Axe Neuroscience Centre de recherche du CHU de Québec-UniversitéLaval(Pavillon CHUL)2705 Boulevard LaurierQuebecQCCanada Institute of Nutrition and Functional Foods QuebecQCCanada Optinutribrain International Associated Laboratory(NutriNeuro FranceINAFCanada)QuebecQCCanada Axe Endocrinologie et Néphrologie Centre de recherche du CHU de Québec-UniversitéLavalQuebecQCCanada département de Médecine Facultéde MédecineUniversitéLavalQuebecQCCanada département de Psychiatrie et Neurosciences Facultéde MédecineQuebecQCCanada

There is a need to develop interventions to slow or reverse the degeneration of dopamine neurons in Parkinson’s disease after *** that preclinical and clinical studies suggest benefits of dietary n-3 polyunsaturated fatty acids,such as docosahexaenoic acid.a.d exercise in Parkinson’s disease,we investigated whether both could synergistically interact to induce recovery of the dopaminergic ***,mice received.a.unilateral stereotactic injection of 6-hydroxydopamine into the striatum to establish an animal model of nigrostriatal *** weeks after lesion,animals were fed.a.docosahexaenoic acid-enriched or a control diet for the next 8 *** this period,the animals had.a.cess to a running wheel,which they could use or *** acid treatment,voluntary exercise,or the combination of both had no effect on(i)distance traveled in the open field test,(ii)the percentage of contraversive rotations in the apomorphine-induction test or(iii)the number of tyrosine-hydroxylase-positive cells in the substantia nigra pars ***,the docosahexaenoic acid diet increased the number of tyrosine-hydroxylase-positive terminals and induced.a.rise in dopamine concentrations in the lesioned *** to docosahexaenoic acid treatment or exercise alone,the combination of docosahexaenoic acid.a.d exercise(i)improved forelimb balance in the stepping test,(ii)decreased the striatal dOPAC/dopamine ratio and(iii)led to increased dopamine transporter levels in the lesioned *** present results suggest that the combination of exercise and docosahexaenoic acid may act synergistically in the striatum of mice with a unilateral lesion of the dopaminergic system and provide support for clinical trials combining nutrition and physical exercise in the treatment of Parkinson’s disease.

关键词： 6-hydroxydopamine dopamine dopamine transporter exercise neurorestoration Parkinson’s disease polyunsaturated fatty acids omega-3

Polyethylene glycol fusion repair of severed sciatic nerves accelerates recovery of nociceptive sensory perceptions in male and female rats of different strains

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Neural Regeneration Research 2025年第9期20卷 2667-2681页

作者： Liwen Zhou Karthik Venkudusamy Emily A.Hibbard Yessenia Montoya Alexa Olivarez Cathy Z.Yang Adelaide Leung Varun Gokhale Guhan Periyasamy Zeal Pathak dale R.Sengelaub George d.Bittner department of Neuroscience University of TexasAustinTXUSA Program in Neuroscience Indiana UniversityBloomingtonINUSA department of Molecular Biosciences University of TexasAustinTXUSA

Successful polyethylene glycol fusion(PEG-fusion)of severed.a.ons following peripheral nerve injuries for PEG-fused.a.ons has been reported to:(1)rapidly restore electrophysiological continuity;(2)prevent distal Wallerian degeneration and maintain their myelin sheaths;(3)promote primarily motor,voluntary behavioral recoveries as assessed by the Sciatic Functional Index;and,(4)rapidly produce correct and incorrect connections in many possible combinations that produce rapid.a.d extensive recovery of functional peripheral nervous system/central nervous system connections and reflex(e.g.,toe twitch)or voluntary *** preceding companion paper describes sensory terminal field reo rganization following PEG-fusion repair of sciatic nerve transections or ablations;howeve r,sensory behavioral recovery has not been explicitly explored following PEG-fusion *** the current study,we confirmed the success of PEG-fusion surgeries according to criteria(1-3)above and more extensively investigated whether PEG-fusion enhanced mechanical nociceptive recovery following sciatic transection in male and female outbred Sprague-dawley and inbred Lewis *** nociceptive responses were assessed by measuring withd.a.al thresholds using von Frey filaments on the dorsal and midplantar regions of the *** von Frey filament tests were a more reliable method than plantar von Frey filament tests to assess mechanical nociceptive sensitivity following sciatic nerve *** withd.a.al thresholds of the sciatic-med.a.ed lateral dorsal region differed significantly across strain but not *** thresholds did not change significantly from baseline in chronic Unoperated.a.d Sham-operated *** sciatic transection,all rats exhibited severe hyposensitivity to stimuli at the lateral dorsal region of the hind.a. ipsilateral to the ***,PEG-fused rats exhibited significantly earlier return to baseline withd.a.al thresholds than Negative

关键词： autophagia axotomy collateral sprouting neuropathic pain peripheral nerve repair polyethylene glycol fusion(PEG-fusion) saphenous nerve sensory neurons sex and strain Wallerian degeneration