基于半导体光放大器交叉偏振调制效应实现正、反相波长变换

利用琼斯矩阵,对基于半导体光放大器中的交叉偏振调制效应实现全光波长变换进行了理论分析.结果表明,利用这种机制可以实现同相与反相波长变换.在实验上同时实现了10Gb/s归零信号的正相与反相波长变换,输出消光比分别达到了6.9 dB和8.1 dB.     

Forced(2+1)-dimensional discrete three-wave equation

We generalize the ■-dressing method to investigate a(2+1)-dimensional lattice,which can be regarded as a forced(2+1)-dimensional discrete three-wave equation.The soliton solutions to the(2+1)-dimensional lattice are given through constructing different symmetry conditions.The asymptotic analysis of one-soliton solution is discussed.For the soliton solution,the forces are zero.     

Inverse scattering transform for the two-component Gerdjikov–Ivanov equation with nonzero boundary conditions: Dark-dark solitons

The two-component Gerdjikov–Ivanov equation with nonzero boundary conditions is studied by the inverse scattering transform. A fundamental set of analytic eigenfunctions is obtained with the aid of the associated adjoint problem. Three symmetry conditions are discussed to curb the scattering data. The behavior of the Jost functions and the scattering matrix at the branch points is discussed. The inverse scattering problem is formulated by a matrix Riemann–Hilbert problem. The trace formula in terms of the scattering data and the so-called asymptotic phase difference for the potential are obtained. The solitons classification is described in detail. When the discrete eigenvalues lie on the circle, the dark-dark soliton is obtained for the first time in this work. And the discrete eigenvalues off the circle generate the dark-bright, bright-bright, breather-breather, M(-type)-W(-type) solitons, and their interactions.     

煤热解模拟新方法—ReaxFF MD的GPU并行与化学信息学分析

针对Reax FF MD模拟煤热解反应机理存在的模拟计算效率和化学反应分析能力缺乏这两个关键问题,本课题组提出将GPU(graphics processing unit)高性能计算与化学信息学分析相结合的新方法,建立了国际上首个基于GPU的Reax FF MD程序系统GMD-Reax及国际上首个Reax FF MD模拟的化学反应分析系统VARx MD,大幅提升了Reax FF MD计算大规模煤分子模型的计算能力,实现了煤热解模拟结果中复杂反应的直接分析.利用该方法可将反映复杂煤结构特点的大规模煤分子模型作为一个整体进行Reax FF MD的模拟,所获得的煤热解主要产物随温度和时间演变的趋势及煤热解详细的化学反应信息,是实验方法或其他计算方法难以得到的.因此本课题组认为GPU并行与化学信息学分析相结合的Reax FF MD模拟新方法为从分子层次上系统认识煤热解转化过程的复杂化学反应机理提供了可能.     

Self-assembly of 3p-Block Metal-based Metal-Organic Frameworks from Structural Perspective

Metal-organic frameworks(MOFs) are a class of porous inorganic-organic hybrid materials, which are constructed from diverse inorganic building units and multi-functional organic ligands. Highly ordered pore structures and tailored functionalization have made MOF materials potential for applications in many fields. Among various MOF materials, 3p-block metal(Al, Ga, and In)-based MOFs exhibit higher chemical stability than divalent transition metal-based MOFs due to their higher valence. In this review, Al-MOFs and In-MOFs were mainly discussed from the perspective of categories of inorganic building blocks, coordination types, and numbers of organic ligands. This review will give intuitive guidance to the design and synthesis of novel 3p-block metal-based MOFs with potential applications.     

All-optical wavelength conversion based on nonlinear polarization rotation (NPR) in SOA and AWG filtering

An all-optical wavelength converter, based on nonlinear polarization rotation (NPR) in semiconductor optical amplifier (SOA) and array waveguide grating (AWG) filtering, is experimentally demonstrated. The wavelength converter can provide excellent operation including extinction ratio and Q factor. The simultaneous two wavelength conversion outputs are successfully obtained at 20 Gb/s.     

An Easily Accessible Ionic Aggregation‐Induced Emission Luminogen with Hydrogen‐Bonding‐Switchable Emission and Wash‐Free Imaging Ability

Ionic fluorophores are powerful tools for the study of environmental science and bio‐imaging. However, traditional ionic dyes usually require long synthetic steps and suffer from a quenching effect caused by aggregation. A water‐soluble ionic aggregation‐induced emission luminogen called DBTA is presented, which is readily accessed by a one‐step reaction. The switchable emission manipulated by hydrogen bonding provided solid evidence for the restriction of intramolecular motions as the mechanism of aggregation‐induced emission. DBTA can not only differentiate solvents with different H‐bond donor acidities but also capable of wash‐free imaging in living HeLa cells and fish larva.     

Synthesis of Cationic Biphen[4, 5]arenes as Biofilm Disruptors

Since bacteria in biofilms are inherently resistant to antibiotics and biofilm-associated infections pose a serious threat to global public health, new therapeutic agents and schemes are urgently needed to meet clinical requirements. Here two quaternary ammonium-functionalized biphen[n]arenes (WBPn, n=4, 5) were designed and synthesized with excellent anti-biofilm potency. Not only could they inhibit the assembly of biofilms, but also eradicate intractable mature biofilms formed by Gram-positive S. aureus and Gram-negative E. coli bacterial strains. Moreover, they could strongly complex a conventional antibiotic, cefazolin sodium (CFZ) with complex stability constants of (7.41±0.29)×10⁴ M⁻¹ for CFZ/WBP4 and (4.98±0.49)×10³ M⁻¹ for CFZ/WBP5. Combination of CFZ by WBP4 and WBP5 synergistically enhanced biofilm eradication performance in vitro and statistically improved healing efficacy on E. coli-infected mice models, providing a novel supramolecular strategy for combating biofilm-associated infections.     

Excited-state absorption and sign tuning of nonlinear refraction in porphyrin derivatives

The nonlinear absorptions and nonlinear refractions of free-base porphyrin (P2) and Zn-porphyrin (ZnP2) were studied using the Z-scan technique at 532 nm with different pulse durations. Both P2 and ZnP2 exhibit reverse saturated absorption attributed to excited-state absorption. The coordination of P2 by Zn ion can alter the nonlinear refraction sign from negative to positive at 4 ns pulse. The results indicate that the sign of self-lensing can be tuned by the coordination of Zn in the porphyrin derivatives. In the case of longer pulse duration, the thermal effect was enhanced to dominate the nonlinear refraction sign, leading to the negative nonlinear refraction repeated appearance.