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  • 1
    In: Advanced Optical Materials, Wiley, Vol. 9, No. 5 ( 2021-03)
    Abstract: Information metasurfaces, including digital coding and programmable metasurfaces, have reformed the design theory of metasurfaces from effective medium to coding pattern, and bridged the physical and digital world. Metasurface hologram has shown great potential in imaging and manipulating electromagnetic waves. In this work, bilayer information metasurfaces are proposed to achieve polarization‐encoded holograms in microwave regime. The designed metasurfaces consist of 3‐bit spin‐decoupled meta‐atoms, which possess ultrathin profiles (0.14λ 0 ) and high cross‐polarization transmittance (over 0.8). The incident wave, which is right‐handed circularly polarized or left‐handed circularly polarized, is encoded with code “0” or “1”. The spin‐decoupled design is combined with diffuse scattering and holographic technology. Based on this, a novel algorithm is proposed to generate coding sequences according to the code of incident wave, to achieve different functionalities for corresponding circularly polarized channels. In this way, polarization‐encoded holograms, including diffuse scattering holograms (code “00”), single channel holograms (code “01” or “10”), and spin‐selective holograms (code “11”), are achieved. Simulated and measured results show that the maximum imaging efficiency can reach up to 65.1%, verifying the high efficiency of this holographic technology. This work is expected to open a way of realizing more complicated and higher efficiency information metasurface holography.
    Type of Medium: Online Resource
    ISSN: 2195-1071 , 2195-1071
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2708158-8
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  • 2
    In: Advanced Optical Materials, Wiley, Vol. 8, No. 11 ( 2020-06)
    Abstract: A class of anisotropic, transmissive electromagnetic metasurfaces is presented, which enable independent and simultaneous control of copolarized phase and amplitude responses to two linear, orthogonal polarizations. By varying the geometrical parameters, the transmission response of the proposed structure can yield a full phase coverage, accompanied by broadly adjustable amplitude and negligible cross‐polarized components. The full amplitude‐phase control together with the novel anisotropic character allows efficient implementation of complicated field manipulations. As representative application examples, which cannot be realized via conventional (phase‐only) metasurfaces, it is presented here: (1) the radiation of multiple equal‐power vortex beams (along arbitrarily predesigned directions, with designable orbital angular momentum modes under different polarizations), and (2) the realization of polarization‐reconfigurable multifocal metalenses. Full‐wave numerical simulations and experimental results demonstrate good agreement and confirm the versatility and effectiveness of the proposed approach to design advanced field‐manipulation systems.
    Type of Medium: Online Resource
    ISSN: 2195-1071 , 2195-1071
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2708158-8
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  • 3
    In: Advanced Functional Materials, Wiley, Vol. 30, No. 39 ( 2020-09)
    Abstract: A metasurface is a thin array of subwavelength elements with designable scattering responses, and metasurface holography is a powerful tool for imaging and field control. The existing metasurface holograms are classified into two types: one is based on phase‐only metasurfaces (including the recently presented vectorial metasurface holography), which has high power efficiency but cannot control the phases of generated fields; while the other is based on phase‐amplitude‐modulated metasurfaces, which can control both field amplitudes and phases in the region of interest (ROI) but has very low efficiency. Here, for the first time, it is proposed to synthesize the field amplitudes and phases in ROI simultaneously and independently by using high‐efficiency phase‐only metasurfaces. All points in ROI may have independent values of field amplitudes and phases, and the requirements for X and Y components may be different in achieving spatially varied polarization states. To this end, an efficient design method based on equivalent electromagnetic model and gradient‐based nonlinear optimization is proposed. Full‐wave simulations and experimental results demonstrate that the phase‐only metasurface designed by the method has 10 times higher efficiency than the phase‐amplitude‐modulated metasurface. This work opens a way to realize more complicated and high‐efficiency metasurface holography.
    Type of Medium: Online Resource
    ISSN: 1616-301X , 1616-3028
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2029061-5
    detail.hit.zdb_id: 2039420-2
    SSG: 11
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  • 4
    Online Resource
    Online Resource
    Wiley ; 2024
    In:  Advanced Optical Materials Vol. 12, No. 6 ( 2024-02)
    In: Advanced Optical Materials, Wiley, Vol. 12, No. 6 ( 2024-02)
    Abstract: Information metasurfaces (IMSs) have been considered to be a revolutionary technology for improving the spectral efficiency of sixth‐generation (6G) wireless communications due to their superior ability to manipulate electromagnetic (EM) waves. However, there are still problems to be solved before the widespread application of IMSs. The first is to reduce power consumption, and the second is to achieve a long‐range remote control. In this paper, a long‐range and nearly passive radio frequency identification (RFID)‐controlled IMS is proposed. The proposed IMS comprises four RFID tags and 8 × 8 elements, each of which is integrated with a single‐pole‐double‐throw switch chip to achieve 1‐bit phase reconfigurability. With the remote control of the RFID system, the IMS can be programmed to switch between three functionalities, including beam splitting, beamforming, and EM‐wave absorption. Experiments are performed and the beam‐splitting functionality is demonstrated. The measurement results indicate that the wireless communication between the RFID reader and the IMS is robust within 21.7 m. Additionally, the power consumption of the IMS is as low as 0.576 mW, which can be negligible. The scheme presented in this paper paves the way for the large‐scale applications of IMSs in 6G wireless communications.
    Type of Medium: Online Resource
    ISSN: 2195-1071 , 2195-1071
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2024
    detail.hit.zdb_id: 2708158-8
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  • 5
    In: ChemInform, Wiley, Vol. 43, No. 27 ( 2012-07-03), p. no-no
    Type of Medium: Online Resource
    ISSN: 0931-7597
    Language: English
    Publisher: Wiley
    Publication Date: 2012
    detail.hit.zdb_id: 2110203-X
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  • 6
    In: Conservation Biology, Wiley
    Abstract: Current biodiversity loss is generally considered to have been caused by anthropogenic disturbance, but it is unclear when anthropogenic activities began to affect biodiversity loss. One hypothesis suggests it began with the Industrial Revolution, whereas others propose that anthropogenic disturbance has been associated with biodiversity decline since the early Holocene. To test these hypotheses, we examined the unique vegetation of evergreen broadleaved forests (EBLFs) in East Asia, where humans have affected landscapes since the early Holocene. We adopted a genomic approach to infer the demographic history of a dominant tree ( Litsea elongata ) of EBLFs. We used Holocene temperature and anthropogenic disturbance factors to calculate the correlation between these variables and historical effective population size of L. elongata with Spearman statistics, and integrated the maximum‐entropy niche model to determine the impact of climate change and anthropogenic disturbance on fluctuation in its effective population size. We identified 9 well‐defined geographic clades for the populations of L. elongata . Based on the estimated historical population sizes of these clades, all the populations contracted, indicating persistent population decline over the last 11,000 years. Demographic history of L . elongata and human population change, change in cropland use, and change in irrigated rice area were significantly negatively correlated, whereas climate change in the Holocene was not correlated with demographic history. Our results support the early human impact hypothesis and provide comprehensive evidence of that early anthropogenic disturbance may contribute to the current biodiversity crisis in East Asia. 题目:早期人类活动导致东亚亚热带常绿阔叶林优势种在过去11,000年间有效种群大小的持续衰退 摘要 当前生物多样性丧失的主因普遍被认为是人类活动的干扰, 但人类活动何时开始导致地球生物多样性的丧失这一重大的科学问题仍不清楚。一些学者的研究认为, 生物多样性的丧失始于工业革命; 另一些研究者则发现, 人类活动导致的生物多样性下降至少可以追溯到全新世早期。为了检验这两种假说, 我们聚焦于东亚亚热带地区, 该地区的土地开发、作物驯化已至少有近万年的历史。本研究立足东亚亚热带地区的特征植被类型, 即亚热带常绿阔叶林(EBLFs), 选取其优势树种樟科木姜子属黄丹木姜子( Litsea elongata )为研究对象, 基于基因组重测序方法研究黄丹木姜子种群在万年尺度下的动态历史。通过生态位模拟, 相关性分析等方法推测全新世气候变化, 人类活动因素(人口增长变化, 耕地面积变化, 灌溉稻作面积变化)与黄丹木姜子有效种群大小波动之间的相关性。研究结果发现, 依据地理分布范围, 黄丹木姜子的种群可划分为9大地理分支, 种群动态历史揭示其9大分支在11,000年以来有效种群大小持续下降的历史过程。相关性分析发现, 有效种群大小在11,000年以来的下降与东亚亚热带地区人口增长变化, 耕地面积变化, 灌溉稻作面积变化呈现显著的负相关, 而与全新世期间的气候变化则不呈现相关性。本研究结果支持早全新世人类活动干扰的假说, 并且为东亚地区早期人类活动与当今生物多样性危机的关联机制提供了全新的证据和认识。 关键词:早期人类活动, 气候变化, 亚热带常绿阔叶林, 全新世, 种群动态历史, 基因组重测序 This article is protected by copyright. All rights reserved
    Type of Medium: Online Resource
    ISSN: 0888-8892 , 1523-1739
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2020041-9
    SSG: 12
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  • 7
    In: Medical Physics, Wiley, Vol. 48, No. 7 ( 2021-07), p. 3679-3690
    Abstract: The dual‐energy computed tomography (DECT) technique is an emerging imaging tool that can better characterize material features and has the potential to be a noninvasive means of predicting lymph node metastasis. The purpose of this study was to establish a DECT‐specified quantitative approach based on a neural network to characterize the sentinel lymph node (SLN). Methods With IRB approval, we retrospectively collected a total of 229 patients (100/229 metastasis) with biopsy proven breast cancer in this study. The chest and axillary spectral CT examinations were performed prior to the axillary lymph node (ALN) surgery. A decoupling convolution network with 11 ROIs from sequential keV (40 to 140 keV with 10 keV increment) was proposed to explicitly extract the spectral and spatial features in a DECT to predict the lymph node status. Focal loss was introduced as the loss function. The metric of the slope of the spectral Hounsfield unit curve measured at the venous phase was used as the baseline approach in comparison to our approach. In additional, a logistic model with radiomic features was also compared to our approach. The area under ROC curve (AUC) was used as the figure of merit to evaluate the classification performance. Results By introducing spectral convolution and focal loss, AUC on test set could be improved by 0.15 and 0.01 separately. Compared to the slope of the spectral curve with the average AUC of 0.611 and radiomic model with AUC of 0.825, the proposed approach demonstrates a considerably better performance, with test set AUC value of 0.837, by using decoupling spectral and spatial convolution together with focal loss function. Conclusions We presented a new decoupling neural network based quantification method for DECT analysis, which might have potential as a noninvasive tool to predict metastasis lymph node status for breast cancer in clinical practice.
    Type of Medium: Online Resource
    ISSN: 0094-2405 , 2473-4209
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 1466421-5
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  • 8
    Online Resource
    Online Resource
    Wiley ; 2024
    In:  Advanced Functional Materials Vol. 34, No. 11 ( 2024-03)
    In: Advanced Functional Materials, Wiley, Vol. 34, No. 11 ( 2024-03)
    Abstract: With the increasing demands for computing powers, wave‐based computation has attracted researcher's attention due to its inherent high speed. Metasurfaces have flexible and powerful capabilities to manipulate electromagnetic waves and are good candidates for building a next‐generation of wave‐based computers. In this work, a computational‐metasurface‐based equation solver that yields real‐time solutions to arbitrary complex matrix equations (CME) in the form of K · x + c = 0 is proposed. Full‐wave simulations and experimental measurements are conducted to verify the functionality of the proposed solver. This work serves to provide a promising technique to overcome some shortcomings of the existing designs and lays the first stone of the bridge toward programmable wave‐space computers.
    Type of Medium: Online Resource
    ISSN: 1616-301X , 1616-3028
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2024
    detail.hit.zdb_id: 2029061-5
    detail.hit.zdb_id: 2039420-2
    SSG: 11
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  • 9
    In: physica status solidi (a), Wiley, Vol. 214, No. 1 ( 2017-01)
    Abstract: We report here the electrical and UV‐photoelectrical performance of transparent indium zinc oxide (IZO) thin film transistors with solution‐processed zirconia (ZrO 2 ) dielectric. The channel layers were deposited by magnetron sputter at room temperature. The ZrO 2 dielectric was deposited by solution process under ambient conditions followed by low temperature annealing. The films were structurally characterized by X‐ray diffraction and atomic force microscope. Good device characteristics have been obtained with a field effect mobility of 30.7 cm 2  V −1 s −1 , a current on/off ratio of 10 5 , a threshold voltage of 0.8 V, and a sub‐threshold swing of 30 mV decade −1 . A resistor‐load inverter was fabricated and shows reasonable transfer characteristics with a gain of about 5 at supply voltage of 2 V. It was observed that the transistors are sensitive to UV illumination. When exposed to ultraviolet light with an intensity of 120 µW cm −2 , the photo‐to‐dark current ratio was more than 10 4 in the depletion region. All the above features make IZO thin film transistor a promising candidate to be also used as a UV‐photo transistor.
    Type of Medium: Online Resource
    ISSN: 1862-6300 , 1862-6319
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 1481091-8
    detail.hit.zdb_id: 208850-2
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  • 10
    In: ChemInform, Wiley, Vol. 39, No. 42 ( 2008-10-14)
    Type of Medium: Online Resource
    ISSN: 0931-7597 , 1522-2667
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2008
    detail.hit.zdb_id: 2110203-X
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