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排序方式: 共有785条查询结果,搜索用时 8 毫秒
1.
近两年.IP电话又叫网络电话的发展受到全球的关注。随着宽带接入的发展,基于宽带接入提供的网络电话具有了更大的生命力。从宽带电话的经营模式出发,探究这类业务的出现时现有话音业务市场的影响,进而分析这类业务的发展前景。 相似文献
2.
我国移动电话用户数已跃居世界第一位,且依然蕴藏着巨大的商机。由此不但引发了日趋激烈的市场竞争,而且造成了产品质量投诉量的居高不下,其中对于存在先天设计缺陷产品的处理目前在我国尚无法可依。国际上对缺陷产品实行的召回制度同样适用于我国。这是市场经济规则的需要,也是商家诚信作风的体现。我国已融入世界经济大潮之中,目前建立手机召回制度是必要和适时的。对生产企业而言,一旦发现缺陷产品流入市场,即刻确认并将其召回是明智之举。 相似文献
3.
Conducting drop tests to investigate impact behavior and identify failure mechanisms of small-size electronic products is
generally expensive and time-consuming. Nevertheless, strict drop/impact performance criteria for hand-held electronic products
such as cellular phones play a decisive role in the design because they must withstand unexpected shocks. The design of product
durability on impact has heavily relied on the designer's intuition and experience. In this study, a reliable drop/impact
simulation for a cellular phone is carried out using the explicit code LS-DYNA. Subsequently globallocal experimental verification
is accomplished by means of high-speed photography and impact response measurement. Using this methodology, we predict potential
damage locations in a cellular phone and compare them with real statistical data. It is envisaged that development of a reliable
methodology of drop/impact simulation will provide us with a powerful and efficient vehicle for improvement of the design
quality and reduction of the product development cycle. 相似文献
4.
Yuan Deng Yihai Yang Yuanhang Xiao He-Lou Xie Ruochen Lan Lanying Zhang Huai Yang 《Advanced functional materials》2023,33(35):2301319
Switchable passive radiative cooling (PRC) smart windows can modulate sunlight transmission and spontaneously emit heat to outer space through atmospheric transparent window, presenting great potential in building energy conservation. However, realizing stable and on-demand control of the cooling efficiency for PRC materials is still challenging. Herein, an electro-controlled polymer-dispersed liquid crystal (PDLC) smart window showing PRC property is designed and prepared by adding mid-infrared emitting reactive monomers into the conventional PDLC matrix. It is found that not only the electro-optical properties but also the PRC efficiency of PRC PDLC film are tunable by regulating the content of the mid-infrared emitting components, film thickness, and micromorphology. This advanced PRC PDLC material achieves a near/sub-ambient temperature when the solar irradiance is below 400 W m−2 and can dynamically manage daytime cooling efficiency. Importantly, its PRC efficiency is capable of being tuned in an on-demand and ultrafast millisecond-scale way, whose controllable transparency enables multistage heat regulation. This study is hoped to provide new inspiration in the preparation of advanced optical devices and energy-efficient equipment. 相似文献
5.
Ur?a?Opara?Kra?ovecEmail author Marko?Topi? Anneke?Georg Andreas?Georg Goran?Dra?i? 《Journal of Sol-Gel Science and Technology》2005,36(1):45-52
Nano-structured WO3-TiO2 layers were prepared by the sol-gel route. To obtain transparent, porous and crack free layers up to 0.8 μ m with a single dipping cycle a templating strategy was used. As a template three-dimensionally network based on organically modified silane was introduced to the WO3 and TiO2 sols. The WO3 layers were dip-coated onto the conductive glass substrate (TCO) and the TiO2 layers on the top of the WO3 layer. The morphology and the structure of the layers were determined by Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive X-Ray Spectroscopy (EDXS), Auger and Infrared spectroscopy. SEM image of the WO3-TiO2 layer confirmed the nano-porosity of the layers and give the size of the particles of about 10 nm for TiO2 and 30 nm for WO3 layer. Further analysis indicated that the titanium sol penetrates the WO3 layer. Particles in the WO3 layer consist of a crystalline monoclinic WO3 core surrounded by a 5–10 nm amorphous phase consisting of WO3, TiO2 and SiO2. The WO3-TiO2 layers were used to assemble all solid state photoelectrochromic (PE) devices. Under 1 sun irradiation (1000 W/m2) the visible transmittance of the PE device changes from 62% to 1.6%. The colouring and bleaching processes last about 10 minutes. 相似文献
6.
MT6572平台是由联发科公司推出的双核Cortex-A7主频1.0GHz的智能手机平台。该平台支持AMR-NB和AMR-WB语音编解码,支持双麦克风噪声消除算法等等。文章介绍了MT6572平台的语音性能特点和高清语音的具体要求,并提出了手机实现高清语音的设计要点。 相似文献
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