Very high modulation efficiency two-sections tapered laser diode at 1060nm for free space optical communications

High-power (more than 500 mW) and high-speed (more than 1 Gbps) tapered lasers at 1060 nm are required in free-space optical communications and (at lower frequencies of around 100 MHz) display applications for frequency doubling to the green. On a 3 mm long tapered laser, we have obtained an open eye diagram at 1 Gbps, together with a high extinction ratio of 11 dB, an optical modulation amplitude of 530 mW, and a high modulation efficiency of 13 W/A. On a 4 mm-long tapered laser, we have obtained an open eye diagram at 700 Mbps, together with a high extinction ratio of 19 dB, a high optical modulation amplitude of 1.6 W, and a very high modulation efficiency of 19 W/A. On a 6 mm-long tapered laser, we have obtained a very high power of 5W CW and a very high static modulation efficiency of 59.8 W/A. © 2011 SPIE.

Radio over fibre enabled sensing and communications system for in building

This paper describes work on radio over fiber distributed antenna systems for improving the quality of radio coverage for in-building applications. The DAS network has also been shown to provide improved detection for Gen 2 UHF RFID tags. Using pre-distortion to reduce the problem of the RFID second harmonic, a simple heterogeneous sensing and communications system is demonstrated. © 2011 NOrthumbria University.

太行花属（Taihangia Yu et Li）种质资源的研究

本文报道了太行花属（Taihangia Yu et Li）的种群分布、生物学特性和离体培养的初步结果。 太行花种群由于环境和生物等方面的原因仅在太行山区有狭小分布。来源于不同地区种群的太行花其形态特征具有丰富的表型，在引种条件下更为显著。而酯酶同工酶和过氧化物酶同工酶分析进一步证实了其遗传的稳定性和同源性。 实验表明，太行花在北纬39°58'，最低温度-11℃的北京北京植物园，露地越冬正常。温度提高至40℃时生长发育受抑制而迟滞，以25℃最为适宜，增殖率最高。太行花对土壤的适应范围较广，在泥炭培养土上移殖的幼苗成活率达97.20%，主根须根发达，叶生长良好。不同强度光照处理12000Lux效果最好。 太行花生育期为230多天，生长积温为3763℃左右。物候期受环境条件和当年气候的影响，不同种群和个体之间有一定的差异。花的性别、花期和开花量等与纬度、海拔主要与温湿度相关。 太行花的茎尖、花芽、花梗、萼片、花瓣和叶子等外植体均能在MS附加不同种类和浓度植物激素的培养基中分化，其分化途径和分化效果因附加成分、外植体类别而异。在含有0.1mg/L IAA和0.5mg/L 6-BA的培养基中，不但能启动花芽正常生长、开花、形成合子胚，而且也能诱导花芽、花梗、茎尖产生花芽和营养芽。在芽的继代培养中，细胞分裂素能大量诱导芽的分化，最好的配比是0.5mg/L 6-BA、0.1mg/L ZJ;只含生长素时可以诱导生根或脱分化，其中生根最好的是0.5mg/L IAA;2.4-D单独使用时，能较好地使花芽、叶等脱分化，其最佳浓度为1.0mg/L。

A quantitative study of Vibrio parahaemolyticus (Sakazaki et al) in Etroplus suratensis (Bloch) and Metapenaeus dobsoni (Miers) from Cochin backwater

Seasonal variation of Vibrio parahaemolyticus in fish (Etroplus sauratensis) and prawn (Metapenaeus dobsoni) was monitored from March 1982 to February 1983. Analyses of total viable count, vibrio-like organisms, V. parahaemolyticus like organisms and V. parahaemolyticus showed that they occur more in prawn than in fish. In a more polluted environment, the counts of V. parahaemolyticus associated with fish were found to be higher than in prawn.