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排序方式: 共有8788条查询结果,搜索用时 14 毫秒
41.
Yeongin Kim Chenxin Zhu Wen-Ya Lee Anna Smith Haowen Ma Xiang Li Donghee Son Naoji Matsuhisa Jaemin Kim Won-Gyu Bae Sung Ho Cho Myung-Gil Kim Tadanori Kurosawa Toru Katsumata John W. F. To Jin Young Oh Seonghyun Paik Soo Jin Kim Lihua Jin Feng Yan Jeffrey B.-H. Tok Zhenan Bao 《Advanced materials (Deerfield Beach, Fla.)》2023,35(1):2203541
Hemispherical image sensors simplify lens designs, reduce optical aberrations, and improve image resolution for compact wide-field-of-view cameras. To achieve hemispherical image sensors, organic materials are promising candidates due to the following advantages: tunability of optoelectronic/spectral response and low-temperature low-cost processes. Here, a photolithographic process is developed to prepare a hemispherical image sensor array using organic thin film photomemory transistors with a density of 308 pixels per square centimeter. This design includes only one photomemory transistor as a single active pixel, in contrast to the conventional pixel architecture, consisting of select/readout/reset transistors and a photodiode. The organic photomemory transistor, comprising light-sensitive organic semiconductor and charge-trapping dielectric, is able to achieve a linear photoresponse (light intensity range, from 1 to 50 W m−2), along with a responsivity as high as 1.6 A W−1 (wavelength = 465 nm) for a dark current of 0.24 A m−2 (drain voltage = −1.5 V). These observed values represent the best responsivity for similar dark currents among all the reported hemispherical image sensor arrays to date. A transfer method was further developed that does not damage organic materials for hemispherical organic photomemory transistor arrays. These developed techniques are scalable and are amenable for other high-resolution 3D organic semiconductor devices. 相似文献
42.
I. N. Mihailescu Adriana Lita V. S. Teodorescu A. Luches M. Martino A. Perrone Maria Gartner 《Journal of Materials Science》1996,31(11):2839-2847
We report the deposition of Si-N films by multipulse excimer laser ( = 308 nm, FWHM = 30 ns) ablation of Si wafers placed in a slow flow of NH3 in the pressure range (1 bar-1 mbar). The films are deposited on to a Si collector placed parallel to the Si target. We succeeded in depositing pure amorphous Si3N4 films at a pressure of 1 mbar of NH3. The deposition rate reached a maximum value of 0.2–0.3 nm per pulse. At lower pressures, the deposited films consist of a fine mixture of three amorphous phases (amorphous stoichiometric silicon nitride, amorphous non-stoichiometric silicon nitride and amorphous silicon). The amorphous silicon is prevalent in films deposited at a pressure of several to several tens of bars. Droplets of polycrystalline -Si are sometimes visible on the film surface. The experimental evidence, is analysed with a view to elucidating the participation in the chemical synthesis of the three main stages of the process: the substance expulsion from the target by laser ablation, the transition through the gas of the expulsed substance and it's final impact on the collector. We conclude that silicon nitride is mostly synthesized during the impact on the collector of the flow of the ablated substance. 相似文献
43.
The ageing of populations has been a topic of discussion during the last few decades, but how is this subject represented in the media, and what images of old age are produced? In this article we present the results of a quantitative content analysis that investigates how the concept of population ageing has been represented in Swedish local and national daily news press between 1988 and 2009, and the old age positions that are offered in these representations. We also use discourse analysis in order to qualitatively examine the ways in which the concept of population ageing is articulated in these news press articles and the old age positions that are thereby constituted. The results show that the concept is constituted as a naturalised expert concept, and is primarily used in order to contextualise articles about future political and economical difficulties or even crises. By articulating population ageing with both political policies, political economy and older people??s (as a group) reported need for care and services, population ageing was constituted as a political economic concern rather than a problem for the aged individual. 相似文献
44.
45.
In the area of product design, sensory dominance can be defined as the relative importance of different sensory modalities for product experience. It is often assumed that vision dominates the other senses. In the present study, we asked 243 participants to describe their experiences with consumer products in various situations: while buying a product, after the first week, the first month, and the first year of usage. The data suggest that the dominant sensory modality depends on the period of product usage. At the moment of buying, vision is the most important modality, but during the usage the other sensory modalities gain importance. The roles of the different modalities during usage are product-dependent. Averaged over 93 products analyzed in this study, after one month of usage touch becomes more important than vision, and after one year vision, touch and audition appear to be equally important. We conclude that to create a long-lasting positive product experience, designers need to consider user-product interaction at different stages of product usage and to determine which sensory modality dominates product experience at each stage. 相似文献
46.
Parallel programming for multimedia applications 总被引:2,自引:2,他引:0
Hari Kalva Aleksandar Colic Adriana Garcia Borko Furht 《Multimedia Tools and Applications》2011,51(2):801-818
Computing capabilities are continuing to increase with the availability of multi core and many core processors. The wide availability
of multi core processors has made parallel programming possible for end user applications running on desktops, workstations,
and mobile devices. While parallel hardware has become common, software that exploits parallel capabilities is just beginning
to take hold. Multimedia applications, with their data parallel nature and large computing requirements will benefit significantly
from parallel programming. In this paper an overview of parallel programming is presented and languages and tools for parallel
programming such as OpenMP and CUDA are introduced within the scope of multimedia applications. 相似文献
47.
Quality control and safety related issues have become more and more important in industrial production of high added value products and chemical specialities during last years. In this regard, many successful applications of multivariate statistical process control (MSPC) for monitoring and diagnosis of batch processes have been presented. It is a common industrial practice to monitor the batch progress by exploiting the information contained in a historical database of successful batches using projection techniques such as principal components analysis (PCA), partial least squares (PLS) and independent component analysis (ICA). In this work, a new MSPC strategy for batch process monitoring is presented. Its distinctive feature is that it works in the space of the original variables. The technique uses only the T2-statistic for detection and identification purposes. The identification of the set of observations that signal the fault is accomplished by decomposing the T2-statistic as a unique sum of each variable contribution. Performance comparisons among the proposed strategy and the most popular PCA-based approaches are carried out by simulation of polymerization and penicillin cultivation batch processes. Results show that the new approach can be successfully applied to monitor this kind of processes since it works very well during both fault detection and identification stages. 相似文献
48.
Privacy policies for shared content in social network sites 总被引:1,自引:0,他引:1
Anna C. Squicciarini Mohamed Shehab Joshua Wede 《The VLDB Journal The International Journal on Very Large Data Bases》2010,19(6):777-796
Social networking is one of the major technological phenomena of the Web 2.0, with hundreds of millions of subscribed users.
Social networks enable a form of self-expression for users and help them to socialize and share content with other users.
In spite of the fact that content sharing represents one of the prominent features of existing Social network sites, they
do not provide any mechanisms for collective management of privacy settings for shared content. In this paper, using game
theory, we model the problem of collective enforcement of privacy policies on shared data. In particular, we propose a solution
that offers automated ways to share images based on an extended notion of content ownership. Building upon the Clarke-Tax
mechanism, we describe a simple mechanism that promotes truthfulness and that rewards users who promote co-ownership. Our
approach enables social network users to compose friendship based policies based on distances from an agreed upon central
user selected using several social networks metrics. We integrate our design with inference techniques that free the users
from the burden of manually selecting privacy preferences for each picture. To the best of our knowledge, this is the first
time such a privacy protection mechanism for social networking has been proposed. We also extend our mechanism so as to support
collective enforcement across multiple social network sites. In the paper, we also show a proof-of-concept application, which
we implemented in the context of Facebook, one of today’s most popular social networks. Through our implementation, we show
the feasibility of such approach and show that it can be implemented with a minimal increase in overhead to end-users. We
complete our analysis by conducting a user study to investigate users’ understanding of co-ownership, usefulness and understanding
of our approach. Users responded favorably to the approach, indicating a general understanding of co-ownership and the auction,
and found the approach to be both useful and fair. 相似文献
49.
O'Brien TM Ritz AM Raphael BJ Laidlaw DH 《IEEE transactions on visualization and computer graphics》2010,16(6):918-926
In this work we present, apply, and evaluate a novel, interactive visualization model for comparative analysis of structural variants and rearrangements in human and cancer genomes, with emphasis on data integration and uncertainty visualization. To support both global trend analysis and local feature detection, this model enables explorations continuously scaled from the high-level, complete genome perspective, down to the low-level, structural rearrangement view, while preserving global context at all times. We have implemented these techniques in Gremlin, a genomic rearrangement explorer with multi-scale, linked interactions, which we apply to four human cancer genome data sets for evaluation. Using an insight-based evaluation methodology, we compare Gremlin to Circos, the state-of-the-art in genomic rearrangement visualization, through a small user study with computational biologists working in rearrangement analysis. Results from user study evaluations demonstrate that this visualization model enables more total insights, more insights per minute, and more complex insights than the current state-of-the-art for visual analysis and exploration of genome rearrangements. 相似文献
50.
In this paper, a novel force sensor based on commercial discrete optoelectronic components mounted on a compliant frame is described. The compliant frame has been designed through an optimization procedure to achieve a desired relation between the applied force and the angular displacement of the optical axes of the optoelectronic components. The narrow-angle characteristics of Light Emitting Diode (LED) and PhotoDetector (PD) couples have been exploited for the generation of a signal proportional to very limited deformation of the compliant frame caused by the external traction force. This sensor is suitable for applications in the field of tendon driven robots, and in particular the use of this sensor for the measurement of the actuator side tendon force in a robotic hand is reported. The design procedure of the sensor is presented together with the sensor prototype, the experimental verification of the calibration curve and of the frame deformation and the testing in a force feedback control system. The main advantages of this sensor are the simplified conditioning electronics, the very high noise-to-signal ratio and the immunity to electromagnetic fields. 相似文献