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plasmonic mid-infrared third harmonic generation in germanium nanoantennas

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Light(Science & Applications) 2018年第1期7卷 19-25页

作者： Marco p.fischer Aaron Riede Kevin Gallacher Jacopo Frigerio Giovanni pellegrini Michele Ortolani Douglas J.paul Giovanni Isella Alfred Leitenstorfer paolo Biagioni Daniele Brida Department of physics and Center for Applied photonics University of Konstanz78457 KonstanzGermany School of Engineering University of GlasgowRankine BuildingOakfield AvenueGlasgow G128LTUK L-NESS Dipartimento di Fisica del Politecnico di MilanoVia Anzani 4222100 ComoItaly Dipartimento di Fisica Politecnico di MilanoPiazza Leonardo da Vinci 3220133 MilanoItaly Department of physics Sapienza University of Rome00185 RomeItaly physics and Materials Science Research Unit University of Luxembourg162a avenue de la FaïencerieL-1511 LuxembourgLuxembourg

We demonstrate third harmonic generation in plasmonic antennas consisting of highly doped germanium grown on silicon substrates and designed to be resonant in the mid-infrared frequency range that is inaccessible with conventional nonlinear plasmonic *** to the near-field enhancement,the result is an ultrafast,subdiffraction,coherent light source with a wavelength tunable between 3 and 5μm,and ideally overlapping with the fingerprint region of molecular *** observe the nonlinearity in this challenging spectral window,a highpower femtosecond laser system equipped with parametric frequency conversion in combination with an all-reflective confocal microscope setup is *** demonstrate spatially resolved maps of the linear scattering cross section and the nonlinear emission of single isolated antenna structures.A clear third-order power dependence as well as mid-infrared emission spectra prove the nonlinear nature of the light *** support the observed resonance length of the double-rod antenna and demonstrate that the field enhancement inside the antenna material is responsible for the nonlinear frequency mixing.

关键词： antenna antennas scattering

滤波连接器为通信技术提供高性价比的互连解决方案

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电子产品世界 2003年第08B期10卷 31-32页

作者： Charles p.fischer WpI Interconnect products公司

目前军事/航天通信、航空、GpS(全球定位系统)以及生产设施的不断计算机化推动了技术的快速发展和变化,从而也拉动对滤波连接器的需求。滤波连接器是具有信号选择能力的器件,其目的是调节可变频率信号并滤除可能对系统有危险的那些信号... 详细信息

目前军事/航天通信、航空、GpS(全球定位系统)以及生产设施的不断计算机化推动了技术的快速发展和变化,从而也拉动对滤波连接器的需求。滤波连接器是具有信号选择能力的器件,其目的是调节可变频率信号并滤除可能对系统有危险的那些信号。滤波连接器将交变电流整流为稳定的直流电流,阻止射频噪声的传输是滤波连接器的一项主要功能。

关键词：滤波连接器 pCB 射频噪声电子噪声电磁干扰

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精镗位置精确的精密孔

组合机床与自动化加工技术 1983年第3期 27-30+2页

作者： p.fischer 李如松

本文介绍加工多轴自动车床主轴鼓轮体用的专用精镗机床的结构、主要特点和工序。图9幅。

关键词：精密孔轮体机床镗模镗床夹具精镗传动轴主轴镗杆多轴自动车床滑台

Diversity, composition and host-species relationships of epiphytic orchids and ferns in two forests in Nepal

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Journal of Mountain Science 2017年第6期14卷 1065-1075页

作者： Yagya p. ADHIKARI Anton fischer Hagen S.fischer Maan B.ROKAYA prakash BHATTARAI Axel GRUppE Geobotany Department of Ecology and Ecosystem Management Technische Universitat Munchen Hans-Carl-von-Carlowitz-Platz 2 85354 Freising Germany Institute of Botany Czech Academy of Sciences Zamek 1 CZ-252 43 Pruhonice Czech Republic Department of Biodiversity Research Global Change Research Institute Czech Academy of Sciences Belidla 4a 60300 Brno Czech Republic Department of Biology University of Bergen Postholes 7803 N-5020 Bergen Norway Zoology - Entomology Department of Animal Science Technische Universitat Munchen Hans-Carl-von-Carlowitz-Platz 85354 Freising Germany

Epiphytic plant species are an important part of biological diversity. It is therefore essential to understand the distribution pattern and the factors influencing such patterns. The present study is aimed at observing the patterns of species richness, abundances and species composition of epiphytic orchids and ferns in two subtropical forests in Nepal. We also studied the relationship of host plants(Schima wallichii and Quercus lanata) and epiphyte species. Data were collected in Naudhara community forest(CF) and the national forest(NF) in Shivapuri Nagarjun National park. The data were analyzed using univariate and multivariate tests. In total, we recorded 41 species of epiphytes(33 orchid and 8 fern species). Orchid species abundance is significantlyhigher in CF compared to NF. Orchid species richness and abundance increased with increasing southern aspect whereas it decreased with increasing canopy cover, and fern species richness increased with host bark roughness. Orchid abundance was positively correlated with increasing bark p H, stem size, tree age and tree height and negatively correlated with increasing steepness of the area. Likewise, fern abundances were high in places with high canopy cover, trees that were tall and big, but decreased with increasing altitude and southern aspect. The composition of the orchid and fern species was affected by altitude, aspect, canopy cover, DBH, number of forks and forest management types. We showed that the diversity of orchid and fern epiphytes is influenced by host characteristics as well as host types. The most important pre-requisite for a high epiphyte biodiversity is the presence of oldrespectively tall trees, independent of the recent protection status. This means:(i) for protection, *** the frame of the national park declaration, such areas should be used which host such old tall trees;and(ii) also in managed forests and even in intensively used landscapes epiphytes can be protected by letting a certain numb

关键词： Environmental factors Epiphytes Large trees Indicator species Multivariate and univariate analyses permutations tests

Gluon number fluctuations and diffusive scaling effect

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Frontiers of physics 2011年第1期6卷 100-105页

作者： Wolfgang fischer Department of physics Bielefeld University of Applied Sciences Bielefeld 33615 Germany

The diffusive scaling is studied based on pomeron loop equations in the fixed coupling case. At Y 〉〉 YDS, the gluon number fluctuations become important, the geometric scaling is replaced by the diffusive scaling. In the diffusive scaling regime, the deep inelastic scattering （DIS） total scattering cross-section is a function of single variable ln[1/（r^2Qs^2（z））]. We show that the deep inelastic scattering experimental data lie on a single curve, which seems to indicate the existence of the diffusive scaling phenomenology in the deep inelastic scattering.

关键词： gluon number fluctuations proton structure function pomeron loop

production of composites with high relative permittivity using the spouted bed technique

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particuology 2019年第1期17卷 184-189页

作者： E. Eichner p.-K. fischer S. Heinrich GA Schneider Institute of Solids process Engineering and particle Technology Denickestr1521073 HamburgGermany Institute of Advanced Ceramics Hamburg University of TechnologyDenickestr1521073 HamburgGermany

This contribution presents a new application of the spouted bed technique. The developed production process involves coating fine copper particles with a polymer in a spouted bed plant and then hot pressing the produced granules to form a compact consisting of a copper–polymer composite with a high filling degree. The fabricated composites possess high relative permittivity, which is advantageous for the production of effective capacitors. With increasing filling degree of copper, the relative permittivity of the composites increased, with a maximum relative permittivity of 214 obtained for the composite containing 78.1 vol% copper. Such a high filling degree can be achieved with conductive particles without obtaining a conductive composite by using the spouted bed technology in the production process. The high relative permittivity results from the high filling degree of particles isolated by a polymer coating.

关键词： Spouted bed High relative permittivity Fine particles Coating Metal-polymer composite

Geometric Bone Modeling:From Macro to Micro Structures

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Journal of Computer Science & Technology 2010年第3期25卷 614-622页

作者： Oded Zaideman Anath fischer Laboratory for Computer Aided Design & Life Cycle Engineering Faculty of Mechanical Engineering Technion Israel Institute of Technology

There is major interest within the bio-engineering community in developing accurate and non-invasive means for visualizing, modeling and analyzing bone micro-structures. Bones are composed of hierarchical bio-composite materials characterized by complex multi-scale structural geometry. The process of reconstructing a volumetric bone model is usually based upon CT/MRI scanned images. Meshes generated by current commercial CAD systems cannot be used for further modeling or analysis. Moreover, recently developed methods are only capable of capturing the micro-structure for small volumes （biopsy samples）. This paper examines the problem of re-meshing a 3D computerized model of bone micro- structure. The proposed method is based on the following phases： defining sub-meshes of the original model in a grid-based structure, remeshing each sub-mesh using the neural network （NN） method, and merging the sub-meshes into a global mesh. Applying the NN method to micro-structures proved to be quite time consuming. Therefore, a parallel, grid-based approach was applied, yielding a simpler structure in each grid cell. The performance of this method is analyzed, and the method is demonstrated on real bone micro-structures. Furthermore, the method may be used as the basis for generating a multi-resolution bone geometric model.

关键词： bone modeling micro-structures micro CT (#CT) scanning technology

Micro-site Conditions of Epiphytic Orchids in a Human Impact Gradient in Kathmandu Valley, Nepal

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Journal of Mountain Science 2012年第3期9卷 331-342页

作者： Yagya prasad ADHIKARI Anton fischer Hagen Siegfried fischer Geobotany Department of Ecology and Ecosystem Management Technische Universitt München Hans-Carl-von-Carlowitz-Platz 2 D-85354 Freising Germany

We studied distribution and site conditions of epiphytic orchids in a gradient of human interference in Kathmandu valley, central Nepal. The aim was to understand the recent distribution pattern of epiphytic orchids, with respect to (i) the micro-site conditions and (ii) the type and intensity of land use. The occurrence of epiphytic orchids was recorded for a grid with 1.5 km cell size. The cells represent different types and intensities of human impact. Site factors such as bark rugosity, bark pH, diameter at breast height (dbh; 1.3 m) of host trees, exposure to wind and sunlight intensity were recorded. With regard to the species richness and abundance of epiphytic orchids, we compared different human impact categories from very strong human impact (settlement area) to very low human impact (national park). Remote sensing was used for a supervised classification of land cover. Ficus religiosa turned out to be the most important host species for orchids in urban areas, while Schima wallichii and Alnus nepalensis significantly host orchids in the other categories. Both species richness and abundance of epiphytic orchids were significantly higher under very low human impact (forest in national park) and also some remaining patches of primary forest than the other regions. Micro-climate is crucial for orchid populations. Host bark pH, bark rugosity, sunlight intensity and host exposure were significantly different for all human impact categories in order to harbour epiphytic orchid species. Habitats with a mixture of mature trees are suitable and essential for the conservation of viable populations of epiphytic orchids in settled areas. The study reveals that to improve the population size of orchids it is essential for future urban forestry to: (i) protect old trees as carriers of existing epiphytic orchid diversity, (ii) protect medium old trees to ensure that they may become old trees, (iii) plant new host trees for the future, (iv) plant in groups instead of sing

关键词： Human impact Host tree Micro-climate Epiphytic orchids Remote sensing Conservation Nepal

Epiphytic orchids and their ecological niche under anthropogenic influence in central Himalayas,Nepal

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Journal of Mountain Science 2016年第5期13卷 774-784页

作者： ADHIKARI Yagya prasad fischer Anton fischer Hagen Siegfried Geobotany Department of Ecology and Ecosystem ManagementTechnische Universit?t München

The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions：（1） What is the ecological niche of the different epiphytic orchid species？（2） What are the ecological factors that threaten epiphytic orchid＇s population under anthropogenic disturbances？ Our study area was the Kathmandu valley, Nepal, with its subtropical forest. We established 156 systematically selected sampling points in the Kathmandu area covering different types of ecosystems under human impacts such as densely populated area, agricultural land, mixed agricultural and settled area, old tree patches, and a natural forest in a national park. The ecological niche of the orchid species was analyzed with a principal component analysis （pCA）. The correlations between the different site factors were statistically significant. Spearman＇s rank correlation matrices showed that the variables land-use intensities with altitude, and height with diameter in breast height （dbh） of host had the highest significant positive correlation coefficient （0.67 and 0.64 respectively）. On the other hand, host bark pH and altitude as well as land use had a significantly strong negative correlation coefficient （-0.80 and -0.61, respectively）. Different epiphytic orchid species interact differently with the given set of environmental factors： for occurrence of Vanda cristata there is no single environmental factor of special influence, while for Rhynehostylis retusa high bark pH and high light availability are important. First two axis of the pCA explained more than 50% of the total variance. Most orchid species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenie influence of orchid population in the Kathmandu Valley are loss of adequate host trees （species and size） and increasing air pollution, resulting in increasing host bark pH.

关键词： Host characteristics Epiphytic orchids Anthropogenic disturbances Canopy ecosystem Ecological niche Himalayas