Post-impoundment biomass and composition of phytoplankton in the Yangtze River

Damming, and thus alteration of stream flow, promotes higher phytoplankton populations and encourages algal blooms (density > 10(6) cells L-1) in the Three Gorges Reservoir (TGR). Phytoplankton composition and biomass were studied in the Yangtze River from March 2004 to May 2005. 107 taxa were identified. Diatoms were the dominant group, followed by Chlorophyta and Cyanobacteria. In the Yangtze River, algal abundance varied from 3.13 x 10(3) to 3.83 x 10(6) cells L-1, and algal biomass was in the range of 0.06 to 659 mg C m(-3). Levels of nitrogen, phosphorus and silica did not show consistent longitudinal changes along the river and were not correlated with phytoplankton parameters. Phytoplankton abundance was negatively correlated with main channel discharge (Spearman r = -1.000, P < 0.01). Phytoplankton abundance and biomass in the Yangtze River are mainly determined by the hydrological conditions rather than by nutrient concentrations.

Enhancement of conductivity and transmittance of ZnO films by post hydrogen plasma treatment

We studied the effects of hydrogen plasma treatment on the electrical and optical properties of ZnO films deposited by radio frequency magnetron sputtering. It is found that the ZnO H film is highly transparent with the average transmittance of 92% in the visible range. Both carrier concentration and mobility are increased after hydrogen plasma treatment, correspondingly, the resistivity of the ZnO H films achieves the order of 10(-3) cm. We suggest that the incorporated hydrogen not only passivates most of the defects and/or acceptors present, but also introduces shallow donor states such as the V-O-H complex and the interstitial hydrogen H-i. Moreover, the annealing data indicate that H-i is unstable in ZnO, while the V-O-H complex remains stable on the whole at 400 degrees C, and the latter diffuses out when the annealing temperature increases to 500 degrees C. These results make ZnO H more attractive for future applications as transparent conducting electrodes.

Raman scattering study on Ga1-xMnxAs prepared by Mn ions implantation, deposition and post-annealing

Raman scattering measurements have been performed in Ga1-xMnxAs crystals prepared by Mn ions implantation, deposition, and post-annealing. The Raman spectrum measured from the implanted surface of the sample shows some weak phonon modes in addition to GaAs-like phonon modes, where the GaAs-like LO and TO phonons are found to be shifted by approximately 4 and 2 cm(-1), respectively, in the lower frequency direction compared to those observed from the unimplanted surface of the sample. The weak vibrational modes observed are assigned to hausmannite Mn3O4 like. The coupled LO-phonon plasmon mode (CLOPM), and defects and As related vibrational modes caused by Mn ions implantation, deposition, and post-annealing are also observed. The compositional dependence of GaAs-like LO phonon frequency is developed for strained and unstrained conditions and then using the observed LOGaAs peak, the Mn composition is evaluated to be 0.034. Furthermore, by analyzing the intensity of CLOPM and unscreened LOGaAs phonon mode, the hole density is evaluated to be 1.84 x 10(18) cm(-3). (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Post-growth and in situ annealing on GaInNAs(Sb) and their application in 1.55 mu m lasers

Rapid thermal annealing (RTA) has been demonstrated as an important way to improve the crystal quality of GaInNAs(Sb)/GaAs quantum wells. However little investigation has been made into their application in laser growth, especially at a wavelength of 1.55 mu m. When a GaAs-based laser is grown, AlGaAs is usually used for cladding layers. The growth of the p-cladding layer usually takes 30-45 min at a growth temperature higher than that of the GaInNAs(Sb) active region, which affects the material quality. To investigate this effect, various post-growth annealing processes were performed to simulate this process. Great enhancement of the PL intensity was obtained by a two-step process which consisted of annealing first at 700 degrees C for 60 s and then at 600 degrees C for 45 min. We transferred this post-growth annealing to in situ annealing. Finally, a GaInNAsSb laser was grown with a 700 degrees C in situ annealing process. Continuous operation at room temperature of a GaAs-based dilute nitride laser with a wavelength beyond 1.55 mu m was realized for the first time.

Post-WIMP环境下笔式交互范式的研究

提出了一种在Post-WIMP环境下的笔式交互范式:PIBG.PIBG范式采用纸笔隐喻,与WIMP范式相比,承载应用信息的交互组件由Window变为Paper和Frame,用户的交互动作由鼠标的点击变为笔的手势.对PIBG范式中静态的界面形式和动态的交互手势进行了研究和设计.结合认知心理学,从信息呈现和交互方式两个方面对该范式的特点进行了阐述.利用GOMS模型,从界面呈现方式、手势的效率、用户满意度三个方面对该范式进行了心理学评估.从评估结果可以看,PIBG范式通过模拟日常纸笔环境,利用用户原有的知识,可以明显地减轻认知负担,提高操作效率.

Post-WIMP界面隐式交互特征研究

首先从认知心理学的角度对Post—WIMP界面下的隐式交互特征进行分析和描述。然后通过对传统界面的交互任务生成结构和Post—WIMP界面的交互任务生成结构进行比较,分析Post—WIMP界面交互任务的生成特点。根据这些特点提出了利用识别技术、上下文感知技术和用户修正技术(User Mediation)相结合的方法来支持Post—WIMP界面的隐式交互，并构造了Post—WIMP界面的交互任务生成框架。这些隐式交互特征的研究将为建立Post—WIMP界面软件框架和交互平台提供底层支持。

基于混合自动机的Post-WIMP界面的建模

Post- WIMP界面作为继当前的主流界面范式—— WIMP界面后的下一代界面范式 ,它和 WIMP界面有着很大的不同 ,通过使用虚拟现实、语音交互、手势交互等技术 ,它能够提供更加自然高效的交互方式 .然而 ,它却难以构造 .为了有效地构造 Post- WIMP界面 ,在构造之前不考虑实现细节 ,而在一个抽象的层次上描述它是一个较好的方法 .首先 ,分析了 Post- WIMP界面的交互本质 ,交互混合性是 Post- WIMP界面一个最为重要的特点 .从形式化系统的角度分析 Post- WIMP界面 ,通过将 Post- WIMP界面抽象为混合系统能够更为准确和严格地分析Post- WIMP界面的特性 .混合自动机是用于描述混合系统的形式化工具 ,将 Post- WIMP界面建模为一组相互协作的混合自动机 .设计了一基于混合自动机理论的半形式化语言 L EAFF作为 Post- WIMP界面的描述工具 .LEAFF通过结合文本描述和图形描述描述 Post- WIMP界面中的交互行为 ,能够准确地反映交互中的控制关系、时序关系 .给出了对两个典型 Post- WIMP界面——虚拟现实交互和笔式交互的描述实例 ,同时讨论了 Post- WIMP界面中交互并行性的描述、交互实时性的验证和从描述到实际交互系统构造的转换 .