Scaling Up DNA Origami Lattice Assembly

The surface-assisted hierarchical assembly of DNA origami nanostructures is a promising route to fabricate regular nanoscale lattices. In this work, the scalability of this approach is explored and the formation of a homogeneous polycrystalline DNA origami lattice at the mica-electrolyte interface over a total surface area of 18.75 cm² is demonstrated. The topological analysis of more than 50 individual AFM images recorded at random locations over the sample surface showed only minuscule and random variations in the quality and order of the assembled lattice. The analysis of more than 450 fluorescence microscopy images of a quantum dot-decorated DNA origami lattice further revealed a very homogeneous surface coverage over cm² areas with only minor boundary effects at the substrate edges. At total DNA costs of € 0.12 per cm², this large-scale nanopatterning technique holds great promise for the fabrication of functional surfaces.     

水蒸汽流化条件下的煤气化实验与模型研究

本文在实验室条件下对赤峰的两种褐煤进行了煤热解气化实验研究，考察了气化室温度和流化状态等实验条件变化对煤气产率，组分的影响，得到了具体条件下的煤气化综合过程实验数据。     

Optical Properties of Mg x Zn1−x O Polycrystalline Thin Films Prepared by Sol-Gel Deposition Method

The Mg _x Zn_1–x O alloy thin films were synthesized on Si and quartz substrates by the sol-gel deposition method. The transmittance and cathodoluminescence spectra of the Mg_0.05Zn_0.95O and Mg_0.15Zn_0.85O nanoparticle films were obtained at room temperature. It was found that the bandgap of Mg_0.05Zn_0.95O and Mg_0.15Zn_0.85O films is as large as 3.72 eV and 3.79 eV, respectively. The ultraviolet emission peaks are located at 376 nm and 370 nm, respectively, for the samples annealed at 600°C. When the annealing temperature is elevated to 1000°C, the band-gap decreases to 3.42 eV and an emission line related to the deep-level defect appears at 500 nm. The mechanism behind these phenomena is discussed.     

聚合物银纹化的分子机理

本文综述了近年来有关聚合物银纹化分子机理方面研究的进展情况。内容包括银纹的起源、生长、断裂过程以及各种结构关系对银纹的影响，并对几种典型的聚合物银纹形态进行了描述。     

Highly efficient Cherenkov radiation generation in the irregular point of hollow-core photonic crystal fiber

Highly efficient Cherenkov radiation(CR) is generated by the soliton self-frequency shift(SSFS) in the irregular point of a hollow-core photonic crystal fiber(HC-PCF) in our laboratory.The impacts of pump power and wavelength on the CR are investigated,and the corresponding nonlinear processes are discussed.When the average power of the 120 fs pump pulse increases from 500 mW to 700 mW,the Raman soliton shifts from 2210 nm to 2360 nm,the output power of the CR increases by 2.3 times,the maximum output power ratio of the CR at 539 nm to that of the residual pump is calculated to be 24.32:1,the width of the output optical spectrum at the visible wavelength broadens from 35 nm to 62 nm,and the conversion efficiency η of the CR in the experiment can be above 32%.     

基于光场调制的纳秒激光图案化石墨烯研究

激光加工技术在石墨烯制备领域得到了许多应用。目前激光图案化石墨烯的方法多为激光逐点扫描, 而单次辐照实现图案化加工的方法鲜有报道。通过间光调制器改变激光的光场, 使光束聚焦成图案, 单次辐照直接在石墨烯样品上烧蚀实现图案化。控制激光能量为合适的值时可将石墨烯清晰地图案化而不损伤硅基底。通过拉曼光谱扫描成像发现石墨烯加工边缘清晰, 精度达到μm量级, 具有加工速度快、无需移动样品等特点。     

Study on the optical limiting properties of the mixed liquid of carbon black suspensions and green tea solution by multi-pulse laser

The optical limiting properties of the mixed liquid of carbon black suspensions (CBS) and green tea solution were studied by using an 8 ns laser pulse at 532\,nm. The optical limiting effects of the CBS and mixed liquid have been compared between 5 and 10\,Hz repetition frequencies with nanosecond laser pulse. The experimental results indicate that the optical limiting threshold of the sample with the incidence laser at 10\,Hz repetition frequency is lower than at 5\,Hz repetition frequency. The possible reasons for the influence of the repetition frequency on the samples are discussed. And by observing the optical radiant distributions when the laser pulse passing through different samples, a possible mechanism for the observed effects is suggested. At the same time, the result shows that the optical limiting of CBS is the dominant factor to optical limiting of the mixed liquid.     

Synthesis of ZnO compound nanostructures via a chemical route for photovoltaic applications

A facile, low-temperature, and low-cost chemical route has been developed to prepare ZnO nanowire and nanosphere compound structures. The morphology, structure, and composition of the yielded products have been examined by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction measurements. We have systematically investigated the optical properties of the ZnO nanostructures by micro-Raman, photoluminescence, and transmission spectroscopy. The results demonstrate that the yielded ZnO nanostructures possess good optical quality with high light absorption. We have further successfully employed the obtained ZnO compound nanostructures in dye-sensitized solar cells. The light-to-electricity conversion results show that the compound nanostructure exhibits a significant enhancement of short-circuit current density due to the increased surface area and light scattering in the compound nanostructures. The present chemical route provides a simple way to synthesize various compound nanostructures with high surface area for nanodevice applications.     

基于磁圆二向色谱的单层MoS_2激子能量和线宽温度依赖特性

以二硫化钼(MoS_2)为代表的过渡金属硫属化物属于二维层状材料,样品可以薄至单层.单层MoS_2是一种直接带隙半导体,在纳米逻辑器件、高速光电探测、纳米激光等领域具有广阔的应用前景.在实际应用中,温度是影响半导体材料能带结构和性质的主要因素之一.因此研究单层二维材料能带的温度依赖特性对理解其物理机理以及开展器件应用具有重要的意义.目前,在广泛采用的测量单层MoS_2反射谱的研究中,激子峰往往叠加在一个很强的光谱背底上,难以准确分辨激子的峰位和线宽.基于自行搭建的显微磁圆二向色谱系统,研究了单层MoS_2在65—300 K温度范围内的反射谱和磁圆二向色谱,结果表明磁圆二向色谱在研究单层材料激子能量和线宽方面具有明显的优势.通过分析变温的磁圆二向色谱,得到了不同温度下的A,B激子的跃迁能量和线宽.通过对激子能量和线宽的温度依赖关系进行拟合,进一步讨论了声子散射对激子线宽的影响.