碳纳米管膜的高温纯化研究

为了获得纯度更高的碳纳米管膜, 保证材料发热稳定性, 需要对通过化学气相沉积法得到的碳纳米管膜进行二次纯化. 通过使用高温纯化炉, 在真空状态下, 从1700℃到3200℃分7挡温度对碳纳米管进行纯化, 并对其含碳量和方块电阻进行比较. 结果表明, 高温纯化后的碳纳米管膜含碳量从95.0%提高到99.9%, 解决了含碳量低的问题. 同时, 在高温纯化中发现碳纳米管膜方块电阻从纯化前3Ω降低到0.5Ω, 方块电阻的降低对碳纳米管膜具有十分重要的意义, 同样对碳纳米管膜后续产品的开发也有重要作用.     

基于级联PPMgLN晶体的双倍/三倍频双波长激光器

本文演示了紧凑的绿色和近红外双色连续波激光光源,其发射波长分别为516 nm和775 nm。设计并制造了级联的周期性极化掺镁铌酸锂晶体,用于同时转换通信波长的二次谐波(SHG)和三次谐波(THG),可以在相同温度下获得绿色和近红外激光的输出。通过建立一个单程激光测量系统,在2 W泵浦功率下获得516 nm的0.15 mW绿光和775 nm的1.19 mW的光,晶体温度控制在30.8 ℃。实验结果将为单激光器泵浦的紧凑型双波长共线激光器提供重要的案例。     

局部分数阶拉普拉斯算子的狄利克雷问题弱解的细正则性

In this paper, we study the Holder regularity of weak solutions to the Dirichlet problem associated with the regional fractional Laplacian (-△)^αΩ on a bounded open set Ω ■R(N ≥ 2) with C^(1,1) boundary ■Ω. We prove that when f ∈ L^p(Ω), and g ∈ C(Ω), the following problem (-△)^αΩu = f in Ω, u = g on ■Ω, admits a unique weak solution u ∈ W^(α,2)(Ω) ∩ C(Ω),where p >N/2-2α and 1/2< α < 1. To solve this problem, we consider it into two special cases, i.e.,g ≡ 0 on ■Ω and f ≡ 0 in Ω. Finally, taking into account the preceding two cases, the general conclusion is drawn.     

Flow-induced shear stress and deformation of a core–shell-structured microcapsule in a microchannel

A numerical model was developed and validated to investigate the fluid–structure interactions between fully developed pipe flow and core–shell-structured microcapsule in a microchannel. Different flow rates and microcapsule shell thicknesses were considered. A sixth-order rotational symmetric distribution of von Mises stress over the microcapsule shell can be observed on the microcapsule with a thinner shell configuration, especially at higher flow rate conditions. It is also observed that when being carried along in a fully developed pipe flow, the microcapsule with a thinner shell tends to accumulate stress at a higher rate compared to that with a thicker shell. In general, for the same microcapsule configuration, higher flow velocity would induce a higher stress level over the microcapsule shell. The deformation gradient was used to capture the microcapsule's deformation in the present study. The effect of Young's modulus on the microcapsule shell on the microcapsule deformation was investigated as well. Our findings will shed light on the understanding of the stability of core–shell-structured microcapsule when subjected to flow-induced shear stress in a microfluidic system, enabling a more exquisite control over the breakup dynamics of drug-loaded microcapsule for biomedical applications.     

游客情感计算的文本大数据挖掘方法比较研究

旅游文本大数据以其方便、快捷和低门槛的特点为游客情感计算提供了极大便利，已经成为旅游大数据的主要来源之一。基于大数据理论和情感理论，以文本大数据为数据源，在全面梳理国内外情感计算相关成果的基础上，利用人工智能中的逻辑/算法编程方法、机器学习方法、深度学习方法对旅游文本大数据进行挖掘，探索最佳的基于文本大数据的游客情感计算方法。研究发现：（1）基于情感词典的游客情感计算模型，其核心是构建情感词典和设计情感计算规则，方法简单，容易实现，适用语料范围广。（2）机器学习，用统计学方法抽取文本中的特征项，具有非线性特征，可靠性较线性特征的情感词典方法高。（3）基于深度学习技术的游客情感计算，效果良好，准确率在85%以上。训练多领域的文本语料易于移植，实用性强，且泛化能力好，较适合大数据时代游客情感计算研究。     

Majorana Representation for a Composite System

International Journal of Theoretical Physics - The Majorana representation, which provides an intuitive way to represent the quantum state by stars on the Bloch sphere, has drawn considerable...     

MCNOs/CdS双效光催化剂的制备及其性能研究

水热合成法制备了不同磁性纳米洋葱碳(MCNOs)负载量(0%、1%、3%、5%)的MCNOs/CdS光催化剂。并通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、X射线光电子能谱(XPS)、紫外可见光光谱(UV-Vis)、磁滞回线测定仪(VSM)对其进行表征,探究了MCNOs负载比例对催化剂在可见光下降解RhB性能及机理的影响。结果表明,MCNOs能有效提高CdS的光催化效果,复合3%MCNOs后降解率为96%,与纯CdS相比降解率提高了30%,磁性分析表明,其具有良好的顺磁性并能实现催化剂的有效回收。MCNOs/CdS在可见光下催化降解RhB的一级反应动力学直线有较好的拟合度,表明制备的催化剂有较好的催化活性。