1960～2005年汕头500hPa高度变化

分析汕头气象站1960-2005年500hPa高度的气候变化特征，得出存在年际和年代

近50年全球气候变暖对珠江口海平面变化趋势的影响

根据1957～2006年全球温度和珠江口验潮站平均潮位资料，分析全球气候变暖

海底沉积物声速实验室测量结果校正研究

海底沉积物实验室测量状态与海底原状态存在较大差异，因此有必要进行声速

末次盛冰期以来西沙海槽天然气水合物储库变化及其对环境的影响

利用Milkov和Sassen的模型计算了目前及末次盛冰期时西沙海槽天然气水合物

海上低空大气波导的遥感反演及数值模拟研究

由于电磁波传播技术的广泛应用，大气环境成为电磁波传播研究的一个重要领域，尤其是天气变化多端的对流层。对流层大气波导是对流层大气的一种异常结构。大气波导可以使通信电路的相互干扰问题变得复杂，既可能干扰其他系统,又可能形成另外的系统，可以使探测系统产生超视距探测、雷达盲区等反常传播问题。然而通信系统或雷达探测系统遭受大气波导影响的时机具有很大的偶然性，它完全取决于对流层大气的特点。假如能够掌握大气波导的变化规律，准确而及时地预测、预报其出现的时间和地域，结合频率、射线波束、天线仰角和发生功率的选择，就能更好地发挥探测及通信设备的作用。因此，根据实际大气环境，分析、预测和预报大气波导，对于评估大气环境对电磁波传播和探测系统性能具有重要的理论意义和实际价值，尤其是在军事领域。然而在海洋大气环境中，特别是在广阔的海洋上，传统的海洋测量手段，如浮标、船只，获取的海洋水文数据稀少，探空数据更少，无法满足现代海洋大气环境监测所需的大范围观测信息，即使获取数据也很难保证数据点时间和空间的有效性；同时海洋大气边界层日变化缓慢，发生的大气波导持续时间长，比较稳定，对于海上舰船通讯等急需开展大气波导环境区域研究。我国是海洋大国，海岸线狭长，更需要开展沿海区域及近海对流层大气波导研究，特别是边界层内低空大气波导环境预测、预报研究。 目前国内大气波导的研究大多数情况下只注重单站波导发生情况，其代表的时空有效性是有限的，而在实际应用中，人们更加关注波导存在区域，因为波导区域决定了电磁波传输范围。本文针对我国近海区域大气波导不同的形成机理和类型，分别进行了研究。对于蒸发波导，本文利用卫星遥感获取海水表面温度、海面风场、气温、相对湿度等资料，建立卫星遥感资料与蒸发波导高度之间的诊断模式，研究大气波导反演算法和预测模型，首次分析了蒸发波导高度的空间不均匀性。对于低空表面波导和悬空波导，利用中尺度数值模式MM5对大气波导进行了系统的研究，填补了国内中尺度大气波导数值模拟研究的空白，同时选取典型的天气过程，进行了中尺度数值模拟个例研究，分析了大气波导形成机理。 本文主要工作如下： 一、结合P-J模式，利用AMSR-E卫星数据用两种神经网络方法反演了热带海域的蒸发波导高度，并进行了比较，两种方法得到的与浮标实测参数计算得到的蒸发波导高度之间的相关系数相当，都为0.82左右，均方根差后者比前者小，分别为2.64米和1.89米。神经网络直接反演蒸发波导高度方法要优于间接反演蒸发波导高度的方法。利用AMSR-E卫星数据直接反演了南海海域的蒸发波导高度，可以清楚看出蒸发波导高度的空间分布的不均匀性，为研究蒸发波导的环境特性奠定基础。 二、以2005年6月2日出现在黄海海域的大气波导为例，设计了三种数值试验，利用MM5模式对大气波导进行了24h数值模拟研究，包括是否加入常规探空资料进行格点分析同化，垂直分层的多寡，粗、细网格模拟比较分析。通过研究得到了以下结论：（1）利用常规资料进行格点同化对海上大气波导影响较小，对陆地影响较大；（2）垂直分层对大气波导特征参数影响明显，层数较多描述大气波导比较合适；（3）对于海上大气波导，细网格刻画大气波导特征参数比较细致，但粗网格的模拟已经足够进行大气波导分析。 三、以NCEP再分析资料为背景场,利用MM5模式，对2005年6月2日至4日出现在黄海海域的大气波导和2008年5月10日12时到11日12时由‘威玛逊’台风引起的大气波导分别进行了数值模拟研究。通过研究发现：模拟的修正折射率廓线与探空数据得到的廓线基本吻合，但是模拟的较强波导强度和高度普遍比实测的要小得多；同时给出了大气波导参数的演变过程，分析了两次大气波导形成的天气过程，说明了模拟的大气波导区域是可靠的和可信的； MM5模式能够模拟出特定天气条件下低空较强大气波导三维空间变化过程，可以为定量地描述大气波导特征提供理论和试验依据。

Responses of a coastal phytoplankton community to increased nutrient input from the Changjiang (Yangtze) River

Nutrient input from the Changjiang River (Yangtze River) has been increasing dramatically since the 1960s. At the mouth of the Changjiang River, the nitrate concentration has increased about three-fold in 40 years, from 20.5 mu mol/L in the 1960s to 59.1 mu mol/L in the 1980s and to 80.6 mu mol/L in 1990-2004. Phosphate concentration increased by a factor of 30%, from 0.59 mu mol/L in the 1980s to 0.77 mu mol/L in 1990-2004. The increasing nitrate input has arisen mostly from the mid and lower reaches of the Changjiang River, where the river meets one of the most strongly developed agriculture areas in China. Responses of the coastal phytoplankton community to the increasing nutrient inputs are also seen in the available monitoring data. First, a trend of increasing phytoplankton standing stock from 1984 to 2002 appeared in the Changjiang River estuary and adjacent coastal waters, especially in late spring. Secondly, the proportion of diatoms in the whole phytoplankton community showed a decreasing trend from about 85% in 1984 to about 60% in 2000. Finally, red tides/harmful algal blooms increased dramatically in this area in terms of both number and scale. About 30-80 red tide events were recorded each year from 2000 to 2005 in the East China Sea. The scale of some blooms has been in excess of 10,000 km(2). (c) 2008 Elsevier Ltd. All rights reserved.

面向可视化纳米操作的DNA分子运动学建模研究

利用原子力显微镜(AFM:Atomic Force Microscopy)对DNA进行单分子纳米操作对生命科学的发展具有特别重要的意义,但是AFM纳米操作缺乏实时视觉反馈的问题依然制约着生物操纵技术的发展.虚拟现实技术是解决该问题的有效方法之一,但是必须预先建立起被操作物体的运动学模型.目前面向可视化纳米操作的建模研究多针对纳米棒、纳米颗粒等刚性物体展开,很少涉及到柔性DNA分子的运动建模方法。针对该问题,本文以弹簧-质点模型为基础,借鉴统计力学在DNA机械特性上的研究成果,提出了一种具有较强物理意义和实际可信度的柔性DNA分子运动学建模方法,并进行了相关仿真实验研究,从而为实现DNA分子的可视化纳米操作提供了理论依据。

Two-Dimensional Kinetics Of Beta(2)-Integrin And Icam-1 Bindings Between Neutrophils And Melanoma Cells In A Shear Flow

Cell adhesion, mediated by specific receptor-ligand interactions, plays an important role in biological processes such as tumor metastasis and inflammatory cascade. For example, interactions between beta(2)-integrin ( lymphocyte function-associated antigen-1 and/or Mac-1) on polymorphonuclear neutrophils (PMNs) and ICAM-1 on melanoma cells initiate the bindings of melanoma cells to PMNs within the tumor microenvironment in blood flow, which in turn activate PMN-melanoma cell aggregation in a near-wall region of the vascular endothelium, therefore enhancing subsequent extravasation of melanoma cells in the microcirculations. Kinetics of integrin-ligand bindings in a shear flow is the determinant of such a process, which has not been well understood. In the present study, interactions of PMNs with WM9 melanoma cells were investigated to quantify the kinetics of beta(2)-integrin and ICAM-1 bindings using a cone-plate viscometer that generates a linear shear flow combined with a two-color flow cytometry technique. Aggregation fractions exhibited a transition phase where it first increased before 60 s and then decreased with shear durations. Melanoma-PMN aggregation was also found to be inversely correlated with the shear rate. A previously developed probabilistic model was modified to predict the time dependence of aggregation fractions at different shear rates and medium viscosities. Kinetic parameters of beta(2)-integrin and ICAM-1 bindings were obtained by individual or global fittings, which were comparable to respectively published values. These findings provide new quantitative understanding of the biophysical basis of leukocyte-tumor cell interactions mediated by specific receptor-ligand interactions under shear flow conditions.

Energy transfer between silicon-oxygen-related defects and Yb3+ in transparent glass ceramics containing Ba2TiSi2O 8 nanocrystals

We report on the conversion of near-ultraviolet radiation of 250-350 nm into near-infrared emission of 970-1100 nm in Yb3+-doped transparent glass ceramics containing Ba2TiSi2O8 nanocrystals due to the energy transfer from the silicon-oxygen-related defects to Yb3+ ions. Efficient Yb3+ emission (F-2(5/2)-> F-2(7/2)) was detected under the excitation of defects absorption at 314 nm. The occurrence of energy transfer is proven by both steady state and time-resolved emission spectra, respectively, at 15 K. The Yb2O3 concentration dependent energy transfer efficiency has also been evaluated, and the maximum value is 65% for 8 mol % Yb2O3 doped glass ceramic. These materials are promising for the enhancement of photovoltaic conversion efficiency of silicon solar cells via spectra modification.

Simultaneous three-photon absorption induced ultraviolet upconversion in Pr3+:Y2SiO5 crystal by femtosecond laser irradiation

Near-infrared to ultraviolet upconversion luminescence was observed in the Pr3+ :Y2SiO5 crystal with 120 fs, 800 mn infrared laser irradiation. The observed emissions at around 270 nm and 305 nm could be assigned to 5d -> 4f transitions of Pr3+ ions. The relationship between the upconversion luminescence intensity and the pump power of the femtosecond laser reveals that the UV emission belongs to simultaneous three-photon absorption induced upconversion luminescence. (c) 2007 Elsevier B.V. All rights reserved.

Multi-channel 2-D pattern transfer model based on imaging optics for submarine laser uplink communication

An optical communication scheme of 2-D pattern transfer based on imaging optics for submarine laser uplink communication (SLUC) is suggested. Unlike the methods aiming at avoiding neighboring crosstalk used in traditional multi-channel optical beam transferring, we make full use of the overlapping of each spreading beam other than controlling divergence effect of each beam to avoid interference noise. The apparent parameters have been introduced to simplify theoretical analysis of optical pattern transfer problem involving underwater condition, with the help of which the complex beam propagation inside two kinds of mediums can be easily reduced to brief beam transfer only inside air medium. In this paper, optical transmission path and receiver terminal optics geometry have been described in detail. The link range equation and system uplink performance analysis have also been given. At last, results of a proof-of-concept experiment indicate good feasibility of the proposed SLUC model. © 2007 Elsevier GmbH. All rights reserved.

Strong visible up-conversion emissions and thermometric applications of Er3+-Yb3+ codoped Al2O3 prepared by the sol-gel method

The Er3+-Yb3+ codoped Al2O3 has been prepared by the sol-gel method using the aluminium isopropoxide [Al(OC3H7)(3)]-derived Al2O3 sols with addition of the erbium nitrate [Er(NO3)(3) center dot 5H(2)O] and ytterbium nitrate [Yb(NO3)(3) center dot 5H(2)O]. The phase structure, including only two crystalline types of doped Al2O3 phases, theta and gamma, was obtained for the 1 mol% Er3+ and 5 mol% Yb3+ codoped Al2O3 at the sintering temperature of 1,273 K. By a 978 nm semiconductor laser diodes excitation, the visible up-conversion emissions centered at about 523, 545, and 660 nm were obtained. The temperature dependence of the green up-conversion emissions was studied over a wide temperature range of 300-825 K, and the reasonable agreement between the calculated temperature by the fluorescence intensity ratio (FIR) theory and the measured temperature proved that Er3+-Yb3+ codoped Al2O3 plays an important role in the application of high temperature sensor.

Nickel(II) and copper(II) complexes containing 2-(2-(5-substitued isoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione ligands: Synthesis, spectral and thermal characterizations

Two new hydrazone chelating ligands, 2-(2-(5-methylisoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione (HL1) and 2-(2-(5-tert-butylisoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane- 1,3-dione (HL2), and their nickel(II) and copper(II) complexes were synthesized using the procedure of diazotization, coupling and metallization. Their structures were postulated based on elemental analysis, H-1 NMR, ESI-MS, FT-IR spectra and UV-vis electronic absorption spectra. Smooth films of these complexes on K9 glass substrates were prepared using spin-coating and their absorption properties were evaluated. The thermal properties of the metal(II) complexes were investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). Different thermodynamic and kinetic parameters namely activation energy (E