Using H3+ and H2D+ as probes of star-forming regions

The H3+ and H2D+ ions are important probes of the physical and chemical conditions in regions of the interstellar medium where new stars are forming. This paper reviews how observations of these species and of heavier ions such as HCO+ and H3O+ can be used to derive chemical and kinematic properties of nearby pre-stellar cores and the cosmic ray ionization rate towards more distant regions of high-mass star formation. Future prospects in the field are outlined at the end.     

Color fringe-projected technique for measuring dynamic objects based on bidimensional empirical mode decomposition

A triple-frequency color fringe-projected technique is presented to measure dynamic objects. Three fringe patterns with a carrier frequency ratio of 1:3:9 are encoded in red, green, and blue channels of a color fringe pattern and projected onto an object's surface. Bidimensional empirical mode decomposition is used for decoupling the cross talk among color channels and for extracting the fundamental frequency components of the three fringe patterns. The unwrapped phase distribution of the high-frequency fringe is retrieved by a three-step phase unwrapping strategy to recover the object's height distribution. Owing to its use of only a single snapshot, the technique is suitable for measuring dynamically changing objects with large discontinuity or spatially isolated surfaces.     

Global warming and hepatotoxin production by cyanobacteria: what can we learn from experiments?

Global temperature is expected to rise throughout this century, and blooms of cyanobacteria in lakes and estuaries are predicted to increase with the current level of global warming. The potential environmental, economic and sanitation repercussions of these blooms have attracted considerable attention among the world’s scientific communities, water management agencies and general public. Of particular concern is the worldwide occurrence of hepatotoxic cyanobacteria posing a serious threat to global public health. Here, we highlight plausible effects of global warming on physiological and molecular changes in these cyanobacteria and resulting effects on hepatotoxin production. We also emphasize the importance of understanding the natural biological function(s) of hepatotoxins, various mechanisms governing their synthesis, and climate-driven changes in food-web interactions, if we are to predict consequences of the current and projected levels of global warming for production and accumulation of hepatotoxins in aquatic ecosystems.     

Isomalt与蛋白糖,甜菊糖及嗦吗啶混合物之甜度评价

本文就合成甜味剂蛋白糖(Aspartame),天然甜味剂甜菊糖(Stevioside)和嗦吗啶(Thau-matin)以及蔗糖衍生物lsomalt进行了甜度评价。通过对比评价试验,得出各甜味剂之甜度/浓度非线性关系。除lsomalt外,其它均为高甜度甜味剂。95%的品尝者认为蛋白糖具有类似蔗糖的甜味,而对于甜菊糖和嗦吗啶,分别有40%和44%的品尝者认为由于其不愉快之后味而不能接受作糖的替代品。本文还探讨了低卡填充剂lsomalt在高甜度甜味剂应用中的作用效果。lsomalt可为软饮料提供良好的“体积”,可有效增加烘烤食品的体积。但lsomalt与加入食品体系中之甜味剂并无协同作用．     

低温等离子体物理的工业应用

等离子体物理应用于材料制造和加工，可能是我们学科的新领域。部分电离的放电已用于工业，并且等离子体性能有大的商业效果和技术影响。然而，低温等离子体科学还没有象高温无碰撞等离子体科学那样充分地得到发展。本文介绍应用的几个主要方面，并举出每个方面一些最重要问题的例子。主题是，气体放电有很大的发展，而且能发现一些向智能挑战的，且有精巧解决办法的问题。     

Heating mechanisms in a near-field optical system

A finite-difference-time-domain and two finite-difference-thermal models are used to study various heating mechanisms in a near-field optical system. It is shown that the dominant mechanism of sample heating occurs from optical power that is transferred from the probe to a metallic thin-film sample. The optical power is absorbed in the sample and converted to heat. The effects of thermal radiation from the probe 's coating and thermal conduction between the probe and the sample are found to be negligible. In a two-dimensional waveguide with TE polarization, most of the optical power is transferred directly from the aperture to the sample. In a two-dimensional waveguide with TM polarization, there is significant optical power transfer between the probe 's aluminum coating and the sample. The power transfer results in a wider thermal distribution with TM polarization than with TE polarization. Using computed temperature distributions in a Co -Pt film, we predict the relative size of thermally written marks in a three-dimensional geometry. The predicted mark size shows a 30 % asymmetry that is due to polarization effects.     

Precision analog demodulation technique for open-loop Sagnac fiber optic gyroscopes

This paper presents an analog technique for the demodulation of interferometric fiber optic gyroscopes signals, based on the calculation of the mean value of the negative cycles of the measured photodetector signal from sinusoidally modulated Sagnac gyroscopes. The developed signal processing circuit was implemented and tested in a laboratory, and it was possible to detect signals as low as 5 microrad. Experimental results measured in a 890 m fiber optic coil gyroscope equipped with the developed circuit showed that the proposed circuit, when compared to the widely used and mature lock-in amplifier technique, presented a 5.1 dB higher signal-to-noise ratio. The circuit is also very stable with the temperature, since a very low drift of 0.04 degrees /h degrees C was measured in a complete gyroscope system. The Brazilian research sounding rocket VSB-30 is currently being equipped with the developed demodulator circuit.     

可生物降解聚乳酸的合成方法

聚乳酸（Polylactic acid, PLA）作为一种以再生植物资源为原料（如玉米）所合成的可生物降解的聚合物,其不仅具有良好的生物降解性能、生物相容性能,还具有较好的力学性能和耐热性。拥有如此良好的性能,使得聚乳酸成了当代绿色环保可持续发展的一种很有潜力的新材料。本文将从聚乳酸的概述、合成方法、应用及展望三个方面进行介绍。