共查询到20条相似文献,搜索用时 140 毫秒
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本文以SDH系统的基本理论为核心,紧紧围绕英国GPT公司生产的(2-155)Mb/sSTM-1SDH设备SMA-1,具体分析和阐述了其系统结构,物理实现方式,同步复用及映射,STM-1帧结构,SDH网同步方式,交叉连接和保护等基本概念和功能,简述了SMA0-1的本机调测流程,介绍了其网管系统EMOS,最后对SDH网的引入和实现提出了看法。 相似文献
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同步数字体系(SDH—SynehronousDigitalHierarchy)是当代最先进的光同步传输体系,表示一整套可以进行同步数字传输、复用和交叉连接的标准化的数字传送等级,其信息传送的结构是同步传送模块(STM—SynchronousTransportModule)。目前有STM—1,比特率为155Mb/s的基本模块;STM-4,比特率为622Mb/s和STM-16,比特率为2.5Gb/S的高阶模块。本文以阿尔卡特(Alcatel)公司的1664SL设备为例,对SDASTM—16光同步传输设备的结构、功能等进行了简单的介绍,以使读者对SDH/STM-16设备有所了解。 相似文献
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降低表面电场原理可大大提高LDMOST的器件性能。本文详细研究了用RESURF原理设计的LDMOST的开态电阻与击穿电压的理论分析模型,并根据这一模型对RESURF LDMOST的优化设计深入的讨论。最后评价了高压RESURF LDMOST在保持器件耐压不变时降低其开态电阻的几种方法。 相似文献
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DC-40GHzMMIC开关叶禹康,俞土法,伍祥冰(南京电子器件研究所,210016)提要*用微波单片集成电路(MMIC)技术设计制作了高隔离度、超快速DC-40GHzMMIC开关(SPST)。开关采用串联、并联单元MESFET兼用的电路结构。芯片尺... 相似文献
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DC-40GHzMMIC开关叶禹康,俞土法,伍祥冰(南京电子器件研究所,210016)提要*用微波单片集成电路(MMIC)技术设计制作了高隔离度、超快速DC-40GHzMMIC开关(SPST)。开关采用串联、并联单元MESFET兼用的电路结构。芯片尺... 相似文献
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使用DSR-4400接收机的体会江苏宜兴有线电视台技术部冯珉随着中央加密频道的开通,并在近期由“中星Ⅴ号”C波段转移到“亚洲Ⅱ号”Ku波段,原卫星接收机也由DSR-3100换为DSR-4400型,二者均为美国GENERALINSTRU-MENT公司的... 相似文献
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S. I. Pokutnyi 《Semiconductors》2003,37(6):718-722
Interband absorption of light in a small semiconductor microcrystal was investigated theoretically within the dipole approximation. An expression for the light-absorption coefficient was derived for the situation where the polarization-related interaction of an electron and hole with the microcrystal surface is dominant. It is shown that the edge of absorption in a microcrystal shifts to shorter wavelengths if the polarization-related interaction of electrons and holes with the microcrystal surface is taken into account. It is ascertained that the absorption edge for small microcrystals is formed by two transitions comparable in intensity; these transitions occur from different levels of size-related quantization for a hole to the lower level of size-related quantization for an electron. 相似文献
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《Electron Device Letters, IEEE》1980,1(4):61-62
It has been previously shown that negative relief images in As2 S3 layers can obtain from photodoping of As2 S3 with silver derived from evaporated silver halide films. In this letter we show that the effective speed of the process can be increased by several orders of magnitude by the addition of a photographic development step to generate a high resolution silver image prior to photodoping. Under these conditions the photodoping is performed by flood rather than imaging light. One of the consequences of the increase in speed is a resolution limited by the Ag halide line structure. 相似文献
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The sensitivity of a broad-band dye laser to selective intracavity absorption is proportional to the number of oscillating modes. This result is obtained from a rate equation model, taking into account the spectral homogeneity, but spatial inhomogeneity of the laser saturation. An increase of absorption sensitivity by a factor of 105, compared to a single-pass measurement, is observed in an experiment with an iodine vapor absorption cell inside the cavity of a CW dye laser. The fluorescence of an external iodine vapor cell provides a convenient selective absorption monitor. 相似文献
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参考谱线法测量倍频Nd:YAG激光器调谐波长的研究 总被引:1,自引:0,他引:1
为了精确测量倍频Nd:YAG激光器的调谐波长,采用碘分子在532nm附近的强吸收谱线作为频率稳定的绝对参考谱线,建立了以碘蒸气为标定物的激光调谐波长测定系统,实际测量了碘蒸气吸收谱线.通过谱线的特征结构与理论吸收谱线的比较,得到了倍频Nd:YAG激光器调谐频率与外加偏压及电位计旋转角度的对应关系,并确定了激光频率跳变点的位置,最后给出了倍频Nd:YAG激光器的调谐范围.结果表明,碘吸收谱线法可以用来精确测量倍频Nd:YAG激光器的调谐波长. 相似文献
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High voltage preparation, characterization, and optical properties of silver dendrites in PVA matrix
In this paper, we present a room-temperature synthesis of silver dendrites in a poly(vinyl alcohol) (PVA)-Ag composite system with the assistance of high voltage. In the silver dendrites, the nanounits are platelike,thus the surface plasmon absorption bands of silver dendrites are tuned from visible to~800 nm, which is due to the template function of PVA and the assistance of high voltage. Scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) data confirm that the structures are crystalline silver embedded in PVA. The absorption results indicate that the ratio of PVA and Ag do not influence the position but the intensity of the near-infrared (NIR) absorption. This material has potential use in the field of bio-application and infrared sensors. 相似文献
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大幅面多路合成全息图复制系统的研究 总被引:1,自引:0,他引:1
多路合成彩虹全息图可以在白光点光源照射下显现出360°伴有动作的立体影像,在许多领域具有广阔的应用前景。为适应市场的需求,研制了多路合成彩虹全息图复制设备和适用于复制多路合成彩虹全息图的超微粒卤化银全息胶片。对多路合成全息图和一般彩虹全息图再现时表面光强分布进行了研究和分析;介绍了多路合成彩虹全息图复制设备和适用于复制多路合成彩虹全息图的超微粒卤化银全息胶片的特性。使用研制的系统和全息胶片复制出的360°的圆筒状多路合成彩虹全息图不仅噪声低,而且衍射效率高。该系统使批量制作多路合成彩虹全息图的工效提高了几十倍。 相似文献