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排序方式: 共有2077条查询结果,搜索用时 15 毫秒
41.
H. Lahlou J.-B. Sanchez Y. Mohsen X. Vilanova F. Berger E. Llobet X. Correig V. Fierro A. Celzard I. Gràcia C. Cané 《Microsystem Technologies》2012,18(4):489-495
In the present study, we present the first steps of the development of a low power consumption GC microsystem for the analysis of benzene in the presence of butadiene, involved in petrochemical industrial applications. This system is made by coupling a low power consumption planar microhotplate based on a preconcentrator with good preconcentration capability and a spiral microchromatographic column that presents a separation capability of both compounds at room temperature, when tested in front of a gas sensor. The first characterization results of the device showed a successful injection of benzene and butadiene when placed in front of the micro-separation module. 相似文献
42.
Shreesha Rao D.S Mikkel Jensen Lars Grüner-Nielsen Jesper Toft Olsen Peter Heiduschka Bj?rn Kemper Jürgen Schnekenburger Martin Glud Mette Mogensen Niels M?ller Israelsen Ole Bang 《光:科学与应用(英文版)》2021,10(7):1372-1384
We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of ... 相似文献
43.
Knoll P Gröller E Höll K Mirzaei S Koriska K Köhn H 《IEEE transactions on medical imaging》2000,19(12):1258-1261
Distributed computing that uses dynamic networks will change the way we work and communicate thanks to the interaction of devices and services, that are automatically added and removed from the network as needed. The Jini technology, which is built atop the Java programming language, provides a homogenous view of the network and extends the ability of code to migrate in Java. This software design model simplifies the configuration and access to hardware devices and software services in a network. Thus, it becomes possible to execute new services without pre-installing software on client machines. This new programming paradigm is especially important in medical applications, where the reliable transmission of information is essential. This paper demonstrates how single photon emission computerized tomography data can be iteratively reconstructed using a Jini service. 相似文献
44.
Analysis of Optical Losses in a Photoelectrochemical Cell: A Tool for Precise Absorptance Estimation 下载免费PDF全文
Peter Cendula Ludmilla Steier Paolo A. Losio Michael Grätzel Jürgen O. Schumacher 《Advanced functional materials》2018,28(1)
Optical losses in a photoelectrochemical (PEC) cell account for a substantial part of solar‐to‐hydrogen conversion losses, but limited attention is paid to the detailed investigation of optical losses in PEC cells. In this work, an optical model of combined coherent and incoherent light propagation in all layers of the PEC cell based on spectroscopic measurements is presented. Specifically, photoelectrodes using transparent conductive substrates such as F:SnO2 coated with thin absorber films are focused. The optical model is verified for hematite photoanodes fabricated by atomic layer deposition and successfully used to determine wavelength‐dependent reflection, transmission, layer absorptances, and charge generation rates. Furthermore, the calculated absorptances enable 20–30% more accurate calculations of the absorbed photon‐to‐current efficiency of PEC cells. Our optical model is a powerful tool for the optimization of the optical performance of PEC cells focusing on single absorber or tandem configurations and represents a cornerstone of a complete (optical and electrical) model for PEC water splitting cells. 相似文献
45.
Ulrich Grünebaum Jürgen Oehm Klaus Schumacher 《Analog Integrated Circuits and Signal Processing》2001,29(3):165-171
This article describes a comprehensive approach to mismatch simulation and modeling as needed for integrated circuit design. Local device mismatch as well as global process variations and parameter correlations are regarded. A method for mismatch modeling based on spatial frequencies is described, which enables to overcome insufficiencies of the first order models. Measurement results are presented to demonstrate the achieved modeling precision. All models and methods mentioned here are commercially available in the simulation tool GAME (General Analysis of Mismatch Effects) which is used in the semiconductor industry since 1998. 相似文献
46.
Yong Hui Lee Jingshan Luo Robin Humphry‐Baker Peng Gao Michael Grätzel Mohammad Khaja Nazeeruddin 《Advanced functional materials》2015,25(25):3925-3933
The effect of the presence of unreacted PbI2 on the perovskite solar cells efficiency is reported. N,N‐Dimethylformamide vapor treatment is introduced to study the influence of complete conversion to a power conversion efficiency of the device. It is discovered that the optimized morphology of the PbI2 under layer is essential to form a dense perovskite layer preventing recombination by direct contact between TiO2 and a hole transporting layer, and to increase the charge collection efficiency. The present findings provide an insight into the morphology and growth mechanism of perovskite layer, the correlation between the device performance, and the film deposition process. 相似文献
47.
48.
Grégory Chatelain Micaël Ripert Carole Farre Salomé Ansanay-Alex Carole Chaix 《Electrochimica acta》2012
We report the use of a four-ferrocene modified oligonucleotide as a probe for DNA detection with a gold electrode microsystem. This oligonucleotide is synthesized by automated solid-phase synthesis with four successive ferrocene moieties at the 5′-end and a C6-thiol modifier group at the 3′-end. The grafting of this 4Fc-DNA probe on a gold electrode microsystem results in the appearance of the ferrocene redox couple in cyclic voltammetry. The probe sequence is a stem-loop structure that folds efficiently on the electrode, thus optimizing electron transfer. Such architecture serves as sensor for DNA detection which is based on hybridization. The resulting disposable voltammetric sensor allowed direct, reagentless DNA detection in a small volume (20 μL). Electrochemical response upon hybridization with complementary short sequence (30-base length) and long sequence (50-base length) strands was observed by differential pulse voltammetry. Current variations were compared. The longer the sequence, the greater the decrease in current. The system's detection limit was estimated at 3.5 pM (0.07 fmol in 20 μL) with the 50-base length target and provided a dynamic detection range between 3.5 pM and 5 nM. Single mismatch detection showed a good level of sensitivity. The system was regenerated twice with no significant loss of Fc signal. Finally, 1 pM sensitivity was reached with a long chain analog of DNA PCR products of Influenza virus. 相似文献
49.
Fabrice Roussière Christophe Baley Grégory Godard Dominique Burr 《Applied Composite Materials》2012,19(2):171-188
Nowadays, the ecological footprint of a material is becoming tremendously important. The Poly l-Lactide Acid (PLLA) matrix
composites reinforced by randomly scattered flax fibres have mechanical properties similar to polyester/glass composites [1], lower environmental impacts and can be compost at the end of their lives. In this study, the mechanical characterization
of biocomposites has been pushed further with the determination of the compressive and tensile properties. Furthermore, the
mechanical properties of single flax fibres have been measured and implemented in a micro-mechanical estimation of the composite
elastic modulus. Tensile and compressive stiffness determined by the mechanical analyses show very good correlations with
the mathematical estimation. 相似文献
50.
To exploit spectrum resources on a secondary basis, a Sensor Network Aided Cognitive Radio Network uses a wireless sensor network that assists a secondary cognitive radio network by providing information about the current primary spectrum occupancy. In this paper we determine the performance for different cell sizes when considering the costs for deployment of base stations in a secondary network that exploits spectrum holes identified by the wireless sensor network. The secondary base station is deployed co-located with a mobile primary network that uses a cellular reuse pattern with seven frequencies. Performance of the secondary system and impact on the primary system are mainly studied in terms of throughput, packet loss and coverage when using spectrum holes in the space, time and frequency domains. Especially, we find that the cell size and configured transmit powers for the secondary system are important for optimal system performance, and that smaller cell sizes and less expensive base stations for the secondary system are beneficial. The impact on primary system performance was found to be low, but that optimal tuning of the sensor network is important. 相似文献