基于遗传算法的LNG气化混合工质配比研究

混合工质合适的配比可以使其放热曲线与LNG气化曲线更好的匹配,减少冷能损失,从而提高循环效率.初选R23和R170为第一级循环的混合工质,R290、R143a、R1270和R125为第二级循环的混合工质.利用Hysys建立了利用LNG冷能发电的两级低温朗肯循环系统.以系统净输出功为目标函数,利用Design Exper...     

Generation of Bessel Beams at mm- and Sub mm-wavelengths by Binary Optical Elements

In this paper, binary optical elements (BOE’s) are designed for generating Bessel beams at mm- and sub mm- wavelengths. The design tool is to combine a genetic algorithm (GA) for global optimization with a two-dimension finite-difference time-domain (2-D FDTD) method for rigorous electromagnetic computation. The design process for converting a normally incident Gaussian beam into a Bessel beam is described in detail. Numerical results demonstrate that the designed BOE’s can not only successfully produce arbitrary order Bessel beams, but also have higher diffraction efficiencies when compared with amplitude holograms.     

Ag(110)表面吸附酞菁铜分子的紫外光电子谱研究

用紫外光电子能谱(UPS)研究了酞菁铜分子在Ag(110)单晶表面上的吸附,随着酞菁铜分子覆盖度增加,衬底Ag的3d电子信号逐渐减弱,在此能带区域出现两个新的谱峰,这两个与吸附有机分子轨道有关的谱峰的束缚能分别为4.45 和6.36 eV.随着覆盖度的增加,在结合能为1.51和9.20 eV处又出现了两个谱峰,它们同样来自吸附有机分子的轨道.随着覆盖度的继续增加,上述四个谱峰的强度逐渐增加,其能量位置均发生了明显的偏移.根据角分辨光电子能谱的实验结果,酞菁铜分子的分子平面基本与衬底表面平行.密度泛函理论计 关键词： 酞菁铜 紫外光电子谱 吸附电子态 密度泛函理论     

Graphene nanoribbon-based supramolecular ensembles with dual-receptor targeting function for targeted photothermal tumor therapy

Triple negative breast cancer (TNBC) is one of the most malignant subtypes of breast cancer. Here, we report the construction of graphene nanoribbon (GNR)-based supramolecular ensembles with dual-receptor (mannose and α_vβ₃ integrin receptors) targeting function, denoted as GNR-Man/PRGD, for targeted photothermal treatment (PTT) of TNBC. The GNR-Man/PRGD ensembles were constructed through the solution-based self-assembly of mannose-grafted GNRs (GNR-Man) with a pyrene-tagged α_vβ₃ integrin ligand (PRGD). Enhanced PTT efficacies were achieved both in vitro and in vivo compared to that of the non-targeting equivalents. Tumor-bearing live mice were administered (tail vein) with GNR-Man/PRGD and then each mice group was subjected to PTT. Remarkably, GNR-Man/PRGD induced complete ablation of the solid tumors, and no tumor regrowth was observed over a period of 15 days. This study demonstrates a new and promising platform for the development of photothermal nanomaterials for targeted tumor therapy.

Dual receptor-targeting supramolecular glycomaterials are constructed based on graphene nanoribbons for the targeted photothermal therapy of triple-negative breast cancer in vivo.     

风湿性关节炎动物模型中血啉甲醚荧光强度的同步检测研究

光动力疗法的疗效依赖于治疗过程中靶组织中光敏剂的含量或浓度 ,而药物在组织中的分布特性是受动物机体调控的 ,因此 ,同一个体不同组织对光敏剂吸收的时间特性需要同时进行检测才能排除个体之间的差异。建立了一套空间三通道激光诱导荧光同步检测装置 ,并用该装置研究了活体大耳白兔风湿性关节炎模型滑膜、软骨和皮肤对血啉甲醚吸收的时间特性。研究结果表明 ,炎性滑膜组织对血啉甲醚的吸收量远大于软骨和皮肤 ,这一差别在静脉给药即刻就很明显 ,在静脉给药后 2 0min内 ,滑膜中的光敏剂药物含量约为软骨和皮肤中的 6倍。因此 ,对于借助血啉甲醚 ,用光动力疗法治疗风湿性关节炎并采用体外照射治疗方案时 ,从注药即刻开始 ,前 2 0min左右进行光照治疗可能是较好的选择。     

Luminescence characteristics of Yb, La codoped yttrium oxide nanopowders

Luminescence characteristics of Yb³⁺, La³⁺ codoped yttrium oxide nanopowders were investigated. The grain size and the crystallinity of (Yb_0.05Y_0.90La_0.05)₂O₃ nanopowders increase with the increase of calcination temperature. The average grain size of the nanopowders calcined at 1100 °C is 66 nm and its cooperative up-conversion luminescence centered at 498 nm was detected due to nanometer size effect and perfect crystallinity. However, the cooperative up-conversion luminescence of (Yb_0.05Y_0.90La_0.05)₂O₃ transparent ceramics was not detected.     

Electrical post-compensation of intrachannel nonlinearities in 10GBaud coherent QPSK transmission systems

Electrical post-compensation of intrachannel nonlinearities in 10GBaud coherent QPSK transmission systems is proposed. The channel inversion method is implemented with a coarse split-step Fourier algorithm through digital signal processing at the receiver side. Simulation results show that simultaneous compensation of intrachannel nonlinearities and chromatic dispersion can be achieved with much simplified signal processing structure. The required optical signal-to-noise ratio at certain bit error ratio is remarkably reduced when the intrachannel nonlinearities induced impairments are dominant.     

基于视觉熵的视觉注意计算模型

提出了一种基于视觉熵的模拟生物视觉信息处理的视觉沣意计算模型,在使用图像的低层特征的基础上,充分考虑了视觉熵中人眼对图像信息的主观量度.该模型首先将图像分成4×4的图像块,分别计算每个图像块的均值、方差、幅度和亮度变化率;采用中央邻域差算子得到各图像的特征图,合并成一个显著图;计算该图中每个显著区域的视觉熵,将最显著Ⅸ域作为视觉注意的焦点,利用人类视觉注意的抑制返回机制,实现视觉注意焦点的转移,从而完成模拟人类视觉注意的整个过程.实验结果表明,该模型基本上能够模拟视觉注意的过程,而且复杂度较低,具有较高的实用价值.     

超光谱成像差分吸收光谱系统烟羽测量研究

研究一种测量污染气体(如SO2,NO2)二维分布的光学遥感方法,即采用超光谱成像差分吸收光谱(DOAS)系统在扫描转台上对污染源排放烟羽进行扫描测量,利用被动差分吸收光谱处理方法对采集到太阳散射光谱进行处理获得柱浓度,结合转台扫描,最终实现污染气体的二维成像解析.着重描述了基于成像差分吸收光谱仪、紫外镜头及扫描转台的超光谱成像差分吸收系统,并利用该系统对热电厂烟羽排放进行了外场测量,该技术为污染源实时成像测量提供了一种简便的方法.     

Long‐Life Room‐Temperature Sodium–Sulfur Batteries by Virtue of Transition‐Metal‐Nanocluster–Sulfur Interactions

Room‐temperature sodium–sulfur (RT‐Na/S) batteries hold significant promise for large‐scale application because of low cost of both sodium and sulfur. However, the dissolution of polysulfides into the electrolyte limits practical application. Now, the design and testing of a new class of sulfur hosts as transition‐metal (Fe, Cu, and Ni) nanoclusters (ca. 1.2 nm) wreathed on hollow carbon nanospheres (S@M‐HC) for RT‐Na/S batteries is reported. A chemical couple between the metal nanoclusters and sulfur is hypothesized to assist in immobilization of sulfur and to enhance conductivity and activity. S@Fe‐HC exhibited an unprecedented reversible capacity of 394 mAh g^?1 despite 1000 cycles at 100 mA g^?1, together with a rate capability of 220 mAh g^?1 at a high current density of 5 A g^?1. DFT calculations underscore that these metal nanoclusters serve as electrocatalysts to rapidly reduce Na₂S₄ into short‐chain sulfides and thereby obviate the shuttle effect.