| 61. |
- Wang, Wei, et al.
(författare)
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Grating-assisted enhanced optical transmission through a seamless gold film
- 2014
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Ingår i: Optics Express. - 1094-4087. ; 22:5, s. 5416-5421
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we experimentally demonstrate enhanced optical transmission through a seamless gold film based on the grating-insulator-metal (GIM) architecture. The transmittance of this GIM structure reaches 40% at 930 nm, showing 3.7 dB and 9.1 dB increase compared with a bare gold film and a continuous metal-insulator-metal stack, respectively. The enhanced transmission is polarization-sensitive and robust for oblique incidence. With tunable transmission peaks, such a device exhibits great potential for applications in optical filtering, polarization detecting and further integration in optoelectronics system.
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| 62. |
- Yang, Tao, et al.
(författare)
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A spatial assessment of hydrologic alteration caused by dam construction in the middle and lower Yellow River, China
- 2008
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 22:18, s. 3829-3843
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Tidskriftsartikel (refereegranskat)abstract
- The ‘range of variability approach’ (RVA) and mapping technique are used to investigate the spatial variability of hydrologic alterations (HA) due to dam construction along the middle and lower Yellow River, China, over the past live decades. The impacts of climate variability oil hydrological process have been removed during wet and dry periods and the focus IS Oil the impacts of human activities, Such as dam construction, on hydrological processes. Results indicate the following: (1) The impacts of the Sanmenxia reservoir oil the hydrologic alteration are relatively slight with a mean HA value of 0.48, ranking in the last place among the four large reservoirs. (2) Xiaolangdi reservoir has significantly changed the natural flow regime downstream with mean HA value of 0.56, ranking it in first place among the large reservoirs. (3) The results of ranked median degrees of 33 hydrologic alteration indicators for 10 stations in the Yellow River show that the hydrologic alteration of Huayuankou ranks the highest among 10 stream gauges. (4) Impacts of reservoirs on hydrological processes downstream of the dams are closely associated with the regulating activities of the reservoirs. At the same time, alterations of streamflow regimes resulting from climatic changes (e.g. precipitation variability) make the situation more complicated and more hydrological observations will be necessary for further analysis. The results of the current study will be greatly beneficial to the regional water resources management and restoration of eco-environmental systems in the middle and lower Yellow River characterized by intensified dam construction under a changing environment. Copyright (C) 2008 John Wiley & Sons, Ltd.
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| 63. |
- Zhang, Lixiu, et al.
(författare)
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Advances in the Application of Perovskite Materials
- 2023
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Ingår i: NANO-MICRO LETTERS. - : SHANGHAI JIAO TONG UNIV PRESS. - 2311-6706. ; 15:1
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Forskningsöversikt (refereegranskat)abstract
- Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices (solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices (artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
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| 64. |
- Zhang, Qiong, et al.
(författare)
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Simulating the mid-Holocene, last interglacial and mid-Pliocene climate with EC-Earth3-LR
- 2021
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Ingår i: Geoscientific Model Development. - : Copernicus GmbH. - 1991-959X .- 1991-9603. ; 14:2, s. 1147-1169
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Tidskriftsartikel (refereegranskat)abstract
- As global warming is proceeding due to rising greenhouse gas concentrations, the Earth system moves towards climate states that challenge adaptation. Past Earth system states are offering possible modelling systems for the global warming of the coming decades. These include the climate of the mid-Pliocene (similar to 3 Ma), the last interglacial (similar to 129-116 ka) and the mid-Holocene (similar to 6 ka). The simulations for these past warm periods are the key experiments in the Paleoclimate Model Intercomparison Project (PMIP) phase 4, contributing to phase 6 of the Coupled Model Intercomparison Project (CMIP6). Paleoclimate modelling has long been regarded as a robust out-of-sample test bed of the climate models used to project future climate changes. Here, we document the model setup for PMIP4 experiments with EC-Earth3-LR and present the large-scale features from the simulations for the mid-Holocene, the last interglacial and the mid-Pliocene. Using the pre-industrial climate as a reference state, we show global temperature changes, large-scale Hadley circulation and Walker circulation, polar warming, global monsoons and the climate variability modes - El Nino-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). EC-Earth3-LR simulates reasonable climate responses during past warm periods, as shown in the other PMIP4-CMIP6 model ensemble. The systematic comparison of these climate changes in past three warm periods in an individual model demonstrates the model's ability to capture the climate response under different climate forcings, providing potential implications for confidence in future projections with the EC-Earth model.
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| 65. |
- Zhang, Zhi, et al.
(författare)
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Two-layered wireless sensor networks for warehouses and supermarkets
- 2009
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The rapid development of wireless sensor network and RFID technologies offers a wide range of novel applications and services. In this paper, we present a two-layered wireless network for warehouses and supermarkets to monitor goods storage and sale, and assist for quality management and market analysis. The hierarchical architecture uses IEEE 802.15.4a impulse ultra-wideband radio (IR-UWB) communication protocol between slave sensor nodes and master sensor nodes, and IEEE 802.11b/g between master sensor nodes and server. The performance of our proposal is evaluated based on the widely used OMNeT++ simulation environment. Simulation results are presented and discussed according to different sampling rates and traffic loads for specific scenarios requirements. © 2009 IEEE.
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| 66. |
- Zhao, Ding, et al.
(författare)
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Ultra-narrow-band light dissipation by a stack of lamellar silver and alumina
- 2014
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 104:22
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Tidskriftsartikel (refereegranskat)abstract
- An ultra-narrow band absorber consisting of continuous silver and alumina films is investigated. Owing to Fabry–Pérot resonance and silver's inherent loss, an ultra-narrow spectral range of light can be entirely trapped in the structure. By varying thicknesses of metallic and dielectric films, absorption peak shifts in visible and near-infrared regions. When two such metal-insulator-metal stacks are cascaded, experimental results show that an ultra-narrow absorption bandwidth of 7 nm is achieved, though theoretical results give that of 2 nm. Features of high-efficiency and ultra-narrow band absorption have huge potential in optical filtering, thermal emitter design, etc.
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| 67. |
- Zhu, Hui Hui, et al.
(författare)
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Large-scale photonic network with squeezed vacuum states for molecular vibronic spectroscopy
- 2024
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Although molecular vibronic spectra generation is pivotal for chemical analysis, tackling such exponentially complex tasks on classical computers remains inefficient. Quantum simulation, though theoretically promising, faces technological challenges in experimentally extracting vibronic spectra for molecules with multiple modes. Here, we propose a nontrivial algorithm to generate the vibronic spectra using states with zero displacements (squeezed vacuum states) coupled to a linear optical network, offering ease of experimental implementation. We also fabricate an integrated quantum photonic microprocessor chip as a versatile simulation platform containing 16 modes of single-mode squeezed vacuum states and a fully programmable interferometer network. Molecular vibronic spectra of formic acid and thymine under the Condon approximation are simulated using the quantum microprocessor chip with high reconstructed fidelity (> 92%). Furthermore, vibronic spectra of naphthalene, phenanthrene, and benzene under the non-Condon approximation are also experimentally simulated. Such demonstrations could pave the way for solving complicated quantum chemistry problems involving vibronic spectra and computational tasks beyond the reach of classical computers.
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| 68. |
- Ahmad, Waqar, et al.
(författare)
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Decoupling capacitance for the power integrity of 3D-DRAM-over-logic system
- 2012
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Ingår i: IEEE 13th Electronics Packaging Technology Conference (EPTC), 2011. - : IEEE conference proceedings. - 9781457719813 ; , s. 590-594
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Konferensbidrag (refereegranskat)abstract
- The 3D-DRAM stacked over the processor is a vibrant technique in order to overcome the memory wall as well as the bandwidth wall problems. We considered a system with two DRAM dies over a single processor die. We assumed the decoupling capacitors to be placed on each DRAM die and connected to the power distribution TSV pairs, where the TSVs pass through the DRAM stack. In this paper we proposed a mathematical model for the optimum value of the decoupling capacitance on each DRAM die along with the optimum values of the effective resistance of the interconnecting power distribution TSV pairs in order to ensure the power integrity of the logic load during switching. The proposed model has a maximum of 1.1% error as compared to the Ansoft Nexxim4.1.
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| 69. |
- Ahmad, Waqar, et al.
(författare)
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Fast Transient Simulation Algorithm for a 3D Power distribution Bus
- 2010
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Ingår i: Proceedings of IEEE Asia Symposium on Quality Electronic Design. ; , s. 343-350
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Konferensbidrag (refereegranskat)abstract
- Extensive transient simulations for on-chip power delivery networks are required to analyze power delivery fluctuations caused by dynamic IR and Ldi/dt drops. Speed and memory has become a bottleneck for simulation of power distribution networks in modern VLSI design where clock frequency is of the order of GHz. The traditional SPICE based tools are very slow and consume a lot of memory during simulation. The problem is further aggravated for huge networks like power distribution network within a stack of ICs inter-connected through TSVs. This type of 3D power distribution network may contain billions of nodes at a time. In this paper we proposed a faster transient simulation algorithm using visual C++. First we reduce 3D power distribution bus containing n nodes to a two terminal 7 network. Then we solve this two terminal reduced network for voltages and currents. After this, we apply back solving algorithm to the network to solve it for each of the intermediate nodes using visual C++. The proposed algorithm is quite accurate with 1-2% error when compared with Ansoft Nexxim4.1. The proposed algorithm is several times faster than Ansoft Nexxim as well as consumes significantly less memory as compared to Nexxim.
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| 70. |
- Ahmad, Waqar, et al.
(författare)
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Modeling of peak-to-peak core switching noise, output impedance, and decoupling capacitance along a vertical chain of power distribution TSV pairs
- 2012
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Ingår i: Analog Integrated Circuits and Signal Processing. - : Springer Science and Business Media LLC. - 0925-1030 .- 1573-1979. ; 73:1, s. 311-328
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Tidskriftsartikel (refereegranskat)abstract
- In this article we propose an efficient and accurate model to estimate peak-to-peak core switching noise, caused by simultaneous switching of logic loads along a vertical chain of power distribution TSV pairs in a 3D stack of dies interconnected through TSVs. The proposed model is accurate with only a 2–3% difference in peak-to-peak core switching noise as compared to the Ansoft Nexxim4.1 equivalent model. The proposed model is 3–4 times faster than Ansoft Nexxim4.1 and uses two times less memory as compared to the Ansoft Nexxim4.1 equivalent model. In this article we also thoroughly establish design guidelines for almost flat output impedance magnitude at each stage of a vertical chain of power distribution TSV pairs to realize a resonance free scenario over a wide operating frequency range. We also establish decoupling capacitance design guidelines based on the optimum output impedance and critically damped supply voltage for the core logic for each stage of a vertical chain of power distribution TSV pairs.
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