共查询到20条相似文献,搜索用时 515 毫秒
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自20世纪90年代锂离子电池商业化以来,其性能已经有了很大的提高,但到目前为止,真正实用的商业化电极材料仍然是最初的钻酸锂(LiCoO2)。尽管与以金属锂为负极的二次锂电池相比,以LiCoO2为正极、炭材料为负极的锂离子电池安全性有了很大程度的提高,小型锂离子电池的安全性得到了保障;但对于大容量、高功率动力型锂离子电池来说,成本和安全性仍是首要解决的核心问题。由于LiCoO2成本高、耐过充性差,不适于用作动力型锂离子电池正极材料,而且钻(Co)元素非常昂贵并有一定的毒性,所以现在的研究已转向开发更合理的新电极材料。 相似文献
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《新材料产业》2008,(12)
2008年北京奥运会和残奥会胜利闭幕了!我国自主研发的595辆多种新能源车辆在会上成功运行200多万公里,为我国政府承诺“科技奥运”,“绿色奥运”的圆满实现作出了重要贡献。在这些纯电动车、混合电动车和燃料电池电动车中,有50辆纯电动大客车(京华客车厂)配以中信国安盟固利公司提供的锰酸锂为正极的动力型锂离子电池,5辆纯电动高级指挥车(山东中通客车厂)中有咸阳威力克能源有限公司用北大先行科技产业有限公司生产的磷酸亚铁锂为正极的动力型锂离子电池。此外,杭州、上海等城市的公交线上也有以锂离子电池为动力的纯电动车行驶。这充分说明,以锰酸锂和磷酸亚铁锂为正极的动力型锂离子电池是安全的,我国有多家企业已经掌握了单体100Ah以上大容量电池的制作、串并联和充放电管理技术,水平已基本上与国外不相上下。 相似文献
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<正>近年来,随着磷酸铁锂、锰酸锂、钛酸锂等高安全、长寿命型锂离子电池电极材料的快速发展,动力及储能锂离子电池在安全性能、能量密度、功率密度、循环寿命、成本降低等方面取得了很大进步,从而使得电动汽车及 相似文献
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<正>锂离子电池作为目前商用电池中的主要电池类型,在实际应用中不断接受使用场景对其提出的各种性能方面的新的挑战。因此,对于锂离子电池卓越性能的追求是行业研究人员一直不断前进的动力。1锂离子电池电解质的分类锂离子电池主要部件包括正极、负极、隔膜以及电解质[1,2]。其中电解质作为离子传导的重要介质,对于电池输出性能以及安全性能均具有重 相似文献
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In wavelength-division-multiplexing systems with optical amplifiers, channel drop or add can cause power changes in the existing channels. We present an analytical formula for the transient power of the existing channels as a function of time when one or more input channel is dropped or added on an erbium-doped fiber amplifier (EDFA). Although this formula was originally derived from perturbation theory of single-stage EDFA's, it is a good approximation of large-power excursion cases as well as two-stage EDFA's. 相似文献
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S Saravanabhavan P Thanikaivelan J Raghava Rao Balachandran Unni Nair 《Clean Technologies and Environmental Policy》2005,7(3):168-176
Environmental impact has become a key issue in the present global industrial activities. A conventional leather processing
method involves multi-step process that employs as well as discharges various inorganic as well as organic materials. Further,
it demands huge resources like water, time and power. An attempt has been made in the study to overcome these problems by
exploring a one-bath chrome tanning together with a wet-finishing process. The one-bath process provides leathers having comparable
physical and bulk properties to that of conventionally processed leather. Integration of chrome tanning with post tanning
improves the uptake of chromium and thereby chrome content in the leathers. The process results in moderate reductions in
pollution loads, water, time and power. More specifically, water usage is reduced by 48% compared to conventional requirement. 相似文献
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无氰高密度镀铜工艺及其在汽车轮毂中的应用 总被引:1,自引:0,他引:1
无氰碱性镀铜技术已发展多年,终因镀液不稳定、预镀层结合力不稳定等问题而不能大规模生产应用.采用无氰高密度镀铜工艺制备了SF-8639无氰高密度铜镀层,对镀液的电流效率、分散能力、覆盖能力、沉积速度以及镀层的结合力、韧性、孔隙率进行了测试,并和国外同类技术及常用的电镀预镀工艺(氰化预镀铜、预镀哑镍)进行对比.结果表明:本工艺镀液稳定,容易控制,分散能力和覆盖能力超过氰化预镀铜;镀液和镀层各项性能达到或超过进口同类无氰碱铜;镀层致密,孔隙率比进口同类无氰碱铜低,结合力好,适用于铝合金轮毂沉锌后的预镀;本工艺在实际生产中已得到了很好的应用,具有良好的发展前景. 相似文献
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We present an approximate analysis of the nonlinear operation of the hollow-waveguide laser, including gain saturation and longitudinal- as well as transverse-field distribution of the laser mode. The model presented is general and can be applied to the study of an arbitrary configuration of the waveguide laser. The laser characteristics obtained reveal that the optimal position of the output mirror (which provides maximal power efficiency of the laser system with the other parameters constant) depends on the output-power level and the mirror-reflectivity coefficient. Moreover, it has been shown that when an addition device is introduced into the cavity, the power efficiency also depends on which end of the laser the light power is extracted from. 相似文献
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Photo‐Thermo‐Mechanical Behaviour Under Quasi‐Static Tensile Conditions of a PMMA‐Core Optical Fibre
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J. L. Pérez‐Castellanos D. S. Montero C. Vázquez J. Zahr‐Viñuela M. González 《Strain》2016,52(1):3-13
As the optical power transmitted by an optical fibre under tensile stress varies with strain, it can be used as a sensor for strain monitoring in structural elements. In the present work, quasi‐static tensile tests of step index polymer optical fibres (POF) with simultaneous measurement of surface temperature and optical power are described. Young's modulus, yield stress and tensile strength are derived from experimental tests. Morphological characterization of the POF fibres using scanning electron microscope images and differential calorimetry technique is performed. The contributions of both elastic and plastic strain components to the variation of temperature and optical power loss are also estimated. The evolution of the POF mechanical properties as well as that of temperature and optical power loss is explained in terms of the progressive relative movement and alignment of the molecular chains in the direction of the applied load. Strain, temperature and optical power loss are then correlated. 相似文献
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Vernon ED Musgrave IO Green J Heathcote R Lancaster KL Mendes C Hawkes SJ Hernandez-Gomez C Pepler DA 《Applied optics》2008,47(18):3258-3263
The development of high peak power and energy laser systems require the assurance that any backscattered radiation will not lead to damage of the laser system. We present the characterization of the backscattered radiation for different target types and conditions at petawatt power levels and intensities (>10(20)W/cm2). We observe that radiation is generated between 700 and 900 nm, as well as the expected self emission and laser fundamental. The percentage of the incident light backscattered reduces as a function of the incident energy and is typically <1% for petawatt laser interactions. 相似文献
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I. I. Galimzyanov Al. F. Gaisin I. T. Fakhrutdinova E. F. Shakirova M. F. Akhatov R. R. Kayumov 《High Temperature》2018,56(2):296-298
We present experimental results on the behavior of the burning of electrical discharge between a nonuniform jet anode and liquid cathode and of the discharge voltage and current pulsations for various voltages of the power supply. We determine the frequency spectrum of the discharge voltage oscillations, as well as the temperatures on the electrolyte cathode surface, by means of infrared thermography and pyrometer. 相似文献