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网络环境下参考咨询服务的时代特征 总被引:1,自引:0,他引:1
汤婵娟 《科技情报开发与经济》2006,16(10):26-27
通过对传统参考咨询服务与数字参考咨询服务的比较分析,阐述了网络环境下图书馆参考咨询的时代特征,提出在网络环境下做好参考咨询服务的相应对策。 相似文献
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We propose a configuration of a wavelength division multiplexing (WDM)-visible light communication (VLC) system using orthogonal frequency division multiplexing (OFDM) modulation and an adaptive Nyquist windowing of the OFDM signal in the receiver. Based on this configuration, we demonstrate a 750-Mb/s WDM-VLC transmission based on RGB light-emitting diode (LED) with a distance of 70 cm. The measured bit error rate (BER) for all channels are under the pre-forwaxd error correction limit of 3,8 × 10-3. The BER performances of all the channels of the proposed WDM-VLC system show considerable improvement compared with those of the system without Nvauist windowing. 相似文献
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We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) signal transmission over fiber, wireless and fiber at Wband (75-110 GHz). The generation of polarization multiplexing millimeter-wave (mm-wave) wireless signal is based on the photonic technique. After 20-km fiber transmission, polarization diversity and heterodyne beating are implemented to convert the polarization components of the polarization-multiplexing signals from the optical baseband to W-band so that up to 16 Gb/s mm-wave signals can be delivered over 2-m 2~2 multiple-input multiple-output (MIMO) wireless link. At the receiver base station (BS), polarization combination reconstructs the PDM-QPSK signal which is then launched into another 20-km fiber. In the experiment, coherent detection is introduced to improve receiver sensitivity and constant modulus algorithm (CMA) is applied for polarization de-multiplexing. The bit-error-ratio (BER) for 16-Gb/s PDM- QPSK signal delivery is below the forward-error-correction (FEC) threshold of 3.8× 10-3 with the optical signal-to-noise ratio (OSNR) above 11.8 dB. 相似文献
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汤婵娟 《科技情报开发与经济》2007,17(19):110-111
分析了用户对传统图书馆的需求,针对大学图书馆特定的文献资料和读者群体,提出了图书馆为用户服务的途径。 相似文献
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汤婵娟 《科技情报开发与经济》2007,17(12):69-70
通过分析新型信息服务机制的发展现状及对图书馆服务所带来的影响,探讨了图书馆服务在新形势下的应对策略及应发挥的作用。 相似文献
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分析了网络时代高校学生生活园区学生思想政治工作面临的挑战,指出网络不仅拓展了高校思想政治教育工作的视野,还是培养人的重要场所,提出高校学生生活园区要充分利用网络资源和信息装备构建学生生活园区绿色网络体系的建议。 相似文献
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汤婵娟 《科技情报开发与经济》2007,17(10):80-81
分析了信息时代图书馆读者服务工作的发展与变化,介绍了图书馆员社会角色的转换与定位,就信息时代图书馆读者服务工作的内容和特点进行了探讨。 相似文献
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