在线社交网络控制实验的现状与展望

在线社交网络已发展成为一个独特的电子生态系统，其应用深刻影响着人们生活的方方面面。由于在线社交网络特性复杂，分析在线社交网络形成和变化中的规律成为当前计算机科学、社会学和物理学的一项挑战。传统上，在线社交网络实证研究主要采用计算机辅助的被动数据获取和分析方式。近年来，在真实大规模在线社交网络上直接进行控制实验从而主动获取数据并开展分析研究的方式广受关注。评述了这一领域的研究进展，包括：社交网络控制实验的主要研究模式；控制实验方法在社交网络结构、信息传播、行为和心理学等领域取得的主要成果以及主要实验工具的适用条件和局限性。最后，展望了人工智能技术在社交网络控制实验中的应用潜力，分析了智能算法对降低实验成本和提高实验效率的作用。     

An effective interference suppression algorithm for visible light communication system based on DBSCAN

In order to improve the signal-to-noise ratio and mitigate the damage of noise to the communication quality,an effective interference suppression algorithm,which is based on the improved density-based spatial clustering of applications with noise algorithms,is proposed for visible light communication systems using the complementary metal–oxide–semiconductor image sensor as the receiver.Experimental results show that the algorithm can learn the region where the payload data is located,filter out the noise data,and greatly decrease the interference.The effect of the algorithm is also studied through bit error ratio performance.     

Efficient Quantum Dot Light-Emitting Diodes Based on Well-Type Thick-Shell CdxZn1−xS/CdSe/CdyZn1−yS Quantum Dots

Device grade quantum dots (QDs) require QDs ensembles to retain their original superior optical properties as in solution. QDs with thick shells are proven effective in suppressing the inter-dot interaction and preserving the emission properties for QDs solids. However, lattice strain–induced defects may form as the shell grows thicker, resulting in a notable photoluminescence quenching. Herein, a well-type Cd_xZn_1−xS/CdSe/Cd_yZn_1−yS QDs is proposed, where ternary alloys CdZnS are adopted to match the lattice parameter of intermediate CdSe by separately adjusting the x and y parameters. The resultant thick-shell Cd_0.5Zn_0.5S/CdSe/Cd_0.73Zn_0.27S QDs reveal nonblinking properties with a high PL QY of 99% in solution and 87% in film. The optimized quantum dot light-emitting diodes (QLEDs) exhibit a luminance of 31547.5 cd m⁻² at the external quantum efficiency maximum of 21.2% under a bias of 4.0 V. The shell thickness shows great impact on the degradation of the devices. The T₅₀ lifetime of the QLEDs with 11.2 nm QDs reaches 251 493 h, which is much higher than that of 6.5 and 8.4 nm QDs counterparts. The performances of the well-type thick-shell QLEDs are comparable to state-of-the-art devices, suggesting that this type of QDs is a promising candidate for efficient optoelectronic devices.     

Structural damage detection using convolutional neural networks combining strain energy and dynamic response

Meccanica - Based on the classification ability of a convolutional neural network (CNN), this paper proposes a structural damage detection method in which a CNN is used to classify the location and...     

血液-血管耦合特性与脉搏波传播特性的关系

脉搏波既不可简单地理解为可压缩血液流体中的压力纵波，也不可简单地理解为沿固体血管传播的涨缩位移横波，而是超乎普通想象的流-固耦合和纵波-横波耦合的复杂波。从分析耦合本构关系的新途径出发，本文中提出了一个流-固耦合/纵波-横波耦合的串联模型，可为解读“位数形势”中医脉诊提供更丰富的信息。结果表明，脉搏波耦合系统的等效体积压缩模量K_s以及相应的耦合系统脉搏波传播速度c_s主要依赖于两个无量纲参数:血液-血管模量比K_b(p)/E(p)和薄壁血管径厚比D(p)/h₀，它们因人而异、因人的不同脉搏位置而异。文中定量分析了它们对c_s的影响，显示人体的K_b/E值在103数量级，从而c_s值在100～101 m/s数量级，以适应人体生理生化反应。由临床有创测量，证实脉搏体积横波与脉搏压力纵波是相耦合地以相同速度传播；还显示脉搏波是在其波阵面上具有氧合生化反应的“生物波”。此外，还讨论了“脉压放大”现象与非线性本构关系和与血管分叉处加载增强反射之间的关系，并讨论了Lewis关于重搏波形成的假设。     

有限群共轭类长度的一点注记

假设G=AB是子群A和B的互相置换积。通过A?B中元素的共轭类长度给出了群G的结构，推广了一些最近的结论。     

Reduction in the $$\mathbf {(4+1)}$$(4+1)-dimensional Fokas equation and their solutions

Nonlinear Dynamics - An integrable extension of the Kadomtsev–Petviashvili (KP) and Davey–Stewartson (DS) equations is investigated in this paper. We will refer to this integrable...     

大断面隧道钻爆冲击波的衰减规律

隧道开挖爆破产生的空气冲击波的破坏效应，将会对人员、机具设备与周围环境造成危害。隧道钻孔爆破冲击波的影响因素比裸露药包爆炸更多、更复杂，研究其衰减规律对采取合适的防护措施意义重大。本文中开展了时速350 km双线铁路大断面隧道钻孔爆破空气冲击波的现场测试，分析了不同工况下冲击波传播规律及影响因素。结果表明:钻爆冲击波超压时程曲线存在多个不同幅值的超压波峰，波峰之间具有明显微差延时的短间隔性，传播至远场未形成稳定的单一平面波，与单一药包爆炸冲击波的传播规律存在差异；钻爆冲击波超压信号由多段与微差延时相对应的子信号叠加而成，子信号数量与毫秒延期雷管段数相同，呈现出典型的时域特征；相同爆破条件下，大断面隧道钻爆时的乳化炸药冲击波转化因数小于小断面巷道工况下的；相较于总药量及最大段药量，按掏槽药量计算的超压峰值与实测超压峰值之间的相关性最强，钻爆冲击波最大超压峰值宜按掏槽段炸药TNT当量确定；隧道内大型机械设备等障碍物改变了钻爆冲击波流场的传播规律，呈现较明显的叠加放大效应。     

H2S gas sensor based on integrated resonant dual-microcantilevers with high sensitivity and identification capability

Detection of trace-level hydrogen sulfide (H₂S) gas is of great importance whether in industrial production or disease diagnosis. This research presents a novel H₂S gas sensor based on integrated resonant dual-microcantilevers which can identify and detect trace-level H₂S in real-time. The sensor consists of two integrated resonant microcantilever sensors with different functions. One cantilever sensor can identify H₂S by outputting positive frequency shift signals, while the other cantilever sensor will detect H₂S as a normally used cantilever sensor with negative frequency shifts. Combined the two cantilever sensors, the proposed gas sensor can distinguish H₂S from a variety of common gases, and the detection limit to H₂S of the sensor is as sensitive as below 1 ppb.