Tailor‐Made Metal–Organic Frameworks from Functionalized Molecular Building Blocks and Length‐Adjustable Organic Linkers by Stepwise Synthesis

In this work, we have demonstrated a family of diamondoid metal–organic frameworks (MOFs) based on functionalized molecular building blocks and length‐adjustable organic linkers by using a stepwise synthesis strategy. We have successfully achieved not only “design” and “control” to synthesize MOFs, but also the functionalization of both secondary building units (SBUs) and organic linkers in the same MOF for the first time. Furthermore, the results of N₂ and H₂ adsorption show that their surface areas and hydrogen uptake capacities are determined by the most optimal combination of functional groups from SBUs and organic linkers, interpenetration, and free volume in this system. A member of this series, DMOF‐6 exhibits the highest surface area and H₂ adsorption capacity among this family of MOFs.     

Electronic transport in the multi-terminal graphene nanodevices

We examined the ac transport attribute of the multi-terminal structures in the absence and presence of magnetic field. We found that the ac response depends on the structural configurations and that the admittance varies with the features of the attached nanoribbons. In the vicinity of Dirac point the dc conductance manifests a dip or peak and the imaginary part (emittance) vanishes or not, depending on whether the attached ribbon is semiconductive or metallic. In the presence of magnetic field, the emittance becomes asymmetric reflecting the dynamic behaviors of electron and hole.     

Size distribution control of metal nanoparticles using femtosecond laser pulse train: a molecular dynamics simulation

Microscopic mechanisms and optimization of metal nanoparticle size distribution control using femtosecond laser pulse trains are studied by molecular dynamics simulations combined with the two-temperature model. Various pulse train designs, including subpulse numbers, separations, and energy distributions are compared, which demonstrate that the minimal mean nanoparticle sizes are achieved at the maximal subpulse numbers with uniform energy distributions. Femtosecond laser pulse trains significantly alter the film thermodynamical properties, adjust the film phase change mechanisms, and hence control the nanoparticle size distributions. As subpulse numbers and separations increase, alternation of film thermodynamical properties suppresses phase explosion, favors critical point phase separation, and significantly reduces mean nanoparticle size distributions. Correspondingly, the relative ratio of two phase change mechanisms causes two distinct nanoparticle size control regimes, where phase explosion leads to strong nanoparticle size control, and increasing ratio of critical point phase separation leads to gentle nanoparticles size control.     

淀粉糖苷表面活性剂的吸湿保湿性能研究

以马铃薯淀粉为糖源,利用转糖苷法合成淀粉糖苷表面活性剂,用重量法测定其吸湿性和保湿性,并与甘油、山梨醇、聚乙二醇、木糖醇、烷基多苷进行比较。结果表明,在30℃,相对湿度43%和相对湿度81%环境条件下,制得的淀粉糖苷表面活性剂的保湿性优于对比试样,72h后保湿率均在70%以上;其吸湿性仅次于甘油,72h后吸湿率达到50%。     

高功率微波作用下热载流子引起n型金属-氧化物-半导体场效应晶体管特性退化研究

高功率微波(HPM)通过使半导体器件特性退化和功能失效,从而干扰电子系统无法正常工作. 针对金属氧化物半导体(MOS)器件的HPM效应, 建立了高功率微波引起n型金属氧化物半导体场效应晶体管(nMOSFET)特性退化的物理过程与模型. 器件仿真结果中nMOSFET的输出特性曲线显示栅极注入HPM引起器件特性退化,包括阈值电压正向漂移、 饱和电流减小、跨导减小等;结合物理模型分析可知, HPM引起的高频脉冲电压使器件进入深耗尽状态, 热载流子数目增多,热载流子效应导致器件特性退化. MOS器件的HPM注入实验结果显示,器件特性曲线、器件模型参数变化趋势与仿真结果一致, 验证了HPM引起nMOSFET特性退化的物理过程与模型.     

基于双透镜外腔结构的窄线宽可调谐半导体激光器

设计了一种具有独特双透镜外腔结构的可调谐窄线宽激光器,利用一个温控50 GHz的标准具提供ITU标准波长序列,通过一个压电陶瓷驱动的Fabry-Pérot可调谐滤波器选择一个标准波长实现单波长输出。实验结果表明:该激光器的调谐范围达到了1 525～1 580 nm,覆盖整个C波段,线宽为37.5 kHz,400 mA电流条件下的输出功率超过50 mW,边模抑制比超过50 dB,达到或超过相干通讯应用的要求和其他单片集成类器件的指标。另外,本结构具有位置容差大、调谐速度快(<3 ms)、易于实现超窄线宽以及波长微调等优点,待实现小型化和标准封装,其大规模应用将成为可能。     

分离扇回旋加速器的等时场在线优化

针对兰州重离子加速器冷却储存环（HIRFL-CSR）的分离扇回旋加速器（SSC）的等时场优化问题,依托HIRFL-CSR的主数据库系统Oracle,设计了系统控制界面,该界面不仅能够读取和给定电源电流值,而且能够实时更新束流相位信息。根据束流相位的实时数据,利用Kb-Kr方法以及Lagrange插值算法建立的等时场,实现了对SSC束流等时场的在线优化。优化后的等时场可以有效控制束流相位的漂移,提高束流品质。     

Wavelength switching based on quantum-dot vertical-cavity surface-emitting laser

This study investigates, for the first time, static and dynamic wavelength switching characteristics of the 1.3 ??m quantum-dot vertical-cavity surface-emitting laser (QD VCSEL). The free-running QD VCSEL with ??1 and ??2 state innately is injected by a laser source with ??1 state. When the injection power exceeds the threshold power, the dominant state of the QD VCSEL changes from ??2 to ??1 state. Results of this study demonstrate that the wavelength switching based on a 1.3 ??m QD VCSEL has a simpler and more cost-effective configuration than those of previous systems.     

Hawking radiation temperatures in non-stationary Kerr black holes with different tortoise coordinate transformations

We apply the Damour–Ruffini–Sannan method to study the Hawking radiations of scalar and Dirac particles in non-stationary Kerr black holes under different tortoise coordinate transformations. We found that all the relevant Hawking radiation spectra show still the blackbody ones, while the Hawking temperatures are strongly related to the used tortoise coordinate transformations. The properties of these dependences are discussed analytically and numerically. Our results imply that proper selections of tortoise coordinate transformations should be important in the studies of Hawking radiations and the correct selection would be given by the experimental observations in the future.     

High-temperature reflective sensor based on single fusion-splicing f iber taper without coating

A high temperature sensor based on an ultra-abrupt tapered fiber Michelson interferometer fabricated by the fusion-splicing method is proposed. The sensor consists of a single abrupt taper and the cleaved surface is used as the reflection mirror. The thermal characteristic is investigated at 25 to 1 000℃. The sensitivity of the sensor is observed to vary with the temperature, that is, 25 and 78 pm/℃ at 25-300 and 300-1 000℃, respectively. The Michelson interferometer sensors have the advantages of simple structure, cost effectiveness, compactness, and simple fabrication process.