Boosted Photocurrent via Heating BiFeo3 Thin Film for UV Photodetector at Wide Temperature Range

The current research on ferroelectric photovoltaic materials is concentrated on enhancing the output photocurrent. As solar cells operate at high temperatures, it is crucial to take into account the effect of increasing temperatures on ferroelectric photovoltaics. In this study, an LNO (lanthanum nickelate, LaNiO₃)/BFO (bismuth ferrate, BiFeO₃)/ITO (indium tin oxide) device is constructed on a mica substrate by sol–gel method. The device achieves output photocurrent enhancement at a wide temperature range (33–183 °C), with the largest photocurrent enhancement at 130 °C, which is 178% relative to room temperature, and the output power is also increased by 9.88 times. At the same time, compared with BFO bulk, it is found that the performance of BFO film is always higher than that of bulk in the test temperature range, and the output photocurrent of BFO film at room temperature is 104 times higher than that of bulk. This article investigates the effect of high temperatures on ferroelectric photovoltaics and also provides a strategy for enhancing the photovoltaic performance of ferroelectric films, providing guidance for future applications of ferroelectric films in flexible solar cells and other applications.     

面向甲状腺结节超声图像分割的多尺度特征融合“h”形网络

目的 准确定位超声甲状腺结节对甲状腺癌早期诊断具有重要意义,但患者结节大小、形状以及位置的不确定性极大影响了结节分割的准确率和模型的泛化能力。为了提高超声甲状腺结节分割的精度,增强泛化性能并降低模型的参数量,辅助医生诊断疾病,减少误诊,提出一种面向甲状腺结节超声图像分割的多尺度特征融合“h”形网络。方法 首先提出一种网络框架,形状与字母h相似,由一个编码器和两个解码器组成,引入深度可分离卷积缩小网络尺寸。编码器用于提取图像特征,且构建增强下采样模块来减少下采样时造成的信息损失,增强解码器特征提取的能力。第1个解码器负责获取图像的初步分割信息;第2个解码器通过融合第1个解码器预先学习到的信息来增强结节的特征表达,提升分割精度,并设计了融合卷积池化金字塔实现多尺度特征融合,增强模型的泛化能力。结果 该网络在内部数据集上的Dice相似系数（Dice similarity coefficients, DSC）、豪斯多夫距离（Hausdorff distance,HD）、灵敏度（sensitivity,SEN）和特异度（specificity,SPE）分别为0.872 1、0.935 6、0.879 7和0.997 3,在公开数据集DDTI（digital database thyroid image）上,DSC和SPE分别为0.758 0和0.977 3,在数据集TN3K（thyroid nodule 3 thousand）上的重要指标DSC和HD分别为0.781 5和4.472 6,皆优于其他模型。结论 该网络模型以较低的参数量提升了甲状腺超声图像结节的分割效果,增强了泛化性能。     

Clustering-based adaptive low-power subframe configuration with load-aware offsetting in dense heterogeneous networks

Heterogeneous Networks (HetNets) and cell densification represent promising solutions for the surging data traffic demand in wireless networks. In dense HetNets, user traffic is steered toward the Low-Power Node (LPN) when possible to enhance the user throughput and system capacity by increasing the area spectral efficiency. However, because of the transmit power differences in different tiers of HetNets and irregular service demand, a load imbalance typically exists among different serving nodes. To offload more traffic to LPNs and coordinate the Inter-Cell Interference (ICI), Third-Generation Partnership Project (3GPP) has facilitated the development of the Cell Range Expansion (CRE), enhanced Inter-Cell Interference Coordination (eICIC) and Further enhanced ICIC (FeICIC). In this paper, we develop a cell clustering-based load-aware offsetting and an adaptive Low-Power Subframe (LPS) approach. Our solution allows the separation of User Association (UA) functions at the User Equipment (UE) and network server such that users can make a simple cell-selection decision similar to that in the maximum Received Signal Strength (max-RSS) based UA scheme, where the network server computes the load-aware offsetting and required LPS periods based on the load conditions of the system. The proposed solution is evaluated using system-level simulations wherein the results correspond to performance changes in different service regions. Results show that our method effectively solves the offloading and interference coordination problems in dense HetNets.     

针对复杂多环网络拓扑的路由改进算法

网络运营商为用户提供的光纤接入主干网大多以环型网络的方式提供服务,然而目前对于大规模、环数众多、连接方式多样化的复杂多环网络缺乏性能优良的路由算法。为解决传统环网结构网络延迟高和传输效率低的问题,提出一种针对复杂多环网络拓扑的路由改进算法,将多环网络中的复杂路由问题转化为单环网中的简单路由问题。在此基础上,通过设计源溯节点还原以及路径还原算法,将单一环网改进为增强环网网络结构,使同一环内通信节点间的路径还原为完整最短路径,并从理论上证明该算法得到的最优路径是无差错的。实验结果表明,相比于现有的优化Dijkstra算法,该算法的搜索空间比提升约13%,具有更好的改进效果,且算法运行时间缩短79%,更适合复杂多环网络的路由计算。     

支持多模态交互的桌面增强显示系统

传统的显示设备在受限的物理空间内难以向用户呈现大量画面和复杂内容,而AR头戴式显示设备通过将三维的可视化内容悬浮显示在用户眼前,在不占用额外物理空间的条件下可增强真实世界的画面显示,呈现形式更为丰富的内容。设计AR虚拟空间与真实电脑画面虚实融合的桌面增强显示系统。通过基于二维码识别的空间定位技术将真实电脑画面映射至虚拟空间内,实现交互空间的统一,同时构建窗口布局计算模型使得系统可以根据用户自定义参数自动生成窗口并设置其布局。在此基础上,利用蓝牙通信、网络传输、操作系统底层映射和结合视线检测的语音识别等技术支持手势、键鼠和语音的多模态交互方式,设计鼠标移动策略以扩展鼠标在三维空间下的多种操作模式。实验结果表明,与隔空手势交互、鼠标交互等传统交互方式相比,该系统在处理常见电脑任务时平均耗时节省10%~30%,具有较高的交互效率,且在跨窗口连续移动和瞬间跳转时能够正确显示鼠标位置。     

5G切片架构下具有重传机制的轮询系统研究

面对海量应用场景及客户需求,传统的轮询系统方案不能满足轮询系统中每个站点所需要的服务质量要求。为降低系统时延,适应更大的网络规模,提出基于5G网络切片的轮询方案。将5G网络切片划分为增强型移动带宽切片、海量机器通信切片和高可靠低时延通信切片,再将这3类切片各自划分出N个更低层子切片,构建3个独立的具有重传机制的完全服务轮询模型。信息分组按照先进先出的规则进入各子切片,由通用服务器进行统一发送。在此基础上,采用概率母函数及马尔可夫链建立非理想信道环境下基于5G网络切片架构的轮询系统数学模型,推导系统平均排队队长和平均等待时间的精确表达式,进行信息分组出错概率和重传阈值与轮询系统性能之间的定量关系分析。基于Matlab的仿真实验结果证明了该模型的正确性,其较重传门限服务时延更少,能够为非理想信道环境下基于5G网络切片架构的轮询系统分析提供一种快速评估机制。     

Plasmon‐Enhanced Spectroscopies with Shell‐Isolated Nanoparticles

Shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS), due to its versatility, has been able to break the long‐term limitations of the material‐ and substrate‐specific generalities in the traditional field of surface‐enhanced Raman spectroscopy. With a shell‐isolated work principle, this method provides an opportunity to investigate successfully in surface, biological systems, energetic materials, and environmental sciences. Both the shell material and core morphology are being improved continuously to meet the requirements in diverse systems, such as the electrochemical studies at single crystal electrode surfaces, in situ monitoring of photoinduced reaction processes, practical applications in energy conversion and storage, inspections in food safety, and the surface‐enhanced fluorescence. Predictably, the concept of shell‐isolated nanoparticle‐enhancement could be expanded to the wider range for the performance of plasmon‐enhanced spectral modifications.     

A Droplet‐Based High‐Throughput SERS Platform on a Droplet‐Guiding‐Track‐Engraved Superhydrophobic Substrate

A novel droplet‐based surface‐enhanced Raman scattering (SERS) sensor for high‐throughput real‐time SERS monitoring is presented. The developed sensors are based on a droplet‐guiding‐track‐engraved superhydrophobic substrate covered with hierarchical SERS‐active Ag dendrites. The droplet‐guiding track with a droplet stopper is designed to manipulate the movement of a droplet on the superhydrophobic substrate. The superhydrophobic Ag dendritic substrates are fabricated through a galvanic displacement reaction and subsequent self‐assembled monolayer coating. The optimal galvanic reaction time to fabricate a SERS‐active Ag dendritic substrate for effective SERS detection is determined, with the optimized substrate exhibiting an enhancement factor of 6.3 × 10⁵. The height of the droplet stopper is optimized to control droplet motion, including moving and stopping. Based on the manipulation of individual droplets, the optimized droplet‐based real‐time SERS sensor shows high resistance to surface contaminants, and droplets containing rhodamine 6G, Nile blue A, and malachite green are successively controlled and detected without spectral interference. This noble droplet‐based SERS sensor reduces sample preparation time to a few seconds and increased detection rate to 0.5 µ L s^?1 through the simple operation mechanism of the sensor. Accordingly, our sensor enables high‐throughput real‐time molecular detection of various target analytes for real‐time chemical and biological monitoring.     

Specific Photothermal Ablation Therapy of Endometriosis by Targeting Delivery of Gold Nanospheres

Endometriosis is difficult to treat since the side effects of the current therapeutic method and the high recurrence rate; thus, newer and safer therapeutic approaches are urgently needed. This work investigates the enhanced permeability and retention effect of CdTe quantum dots (QDs) and hollow gold nanospheres (HAuNS) in endometriosis to increase the delivery of HAuNS into lesion cells. The surface of HAuNS is successfully conjugated with a TNYL peptide that has specific affinity for the EphB4 receptor, which is a member of the Eph family of receptor tyrosine kinases. It is found that the EphB4 receptor is overexpressed in endometriosis lesions. The data indicate that both QDs and HAuNS can efficiently accumulate in endometriotic lesions through permeable vessels and the TNYL‐conjugated HAuNS (TNYL‐HAuNS) accumulate more via the interaction with EphB4. The specific photothermal ablation therapy based on TNYL‐HAuNS significantly inhibits the growth of the endometriotic volume and induces the atrophy and degeneration of ectopic endometrium with no detectable toxicity to the normal organs. The level of TNF‐α and estradiol also significantly decreases in the endometriotic lesions, indicating that the treatment enables a recovery from hormonal imbalance and inflammatory injury. This work can be a valuable reference for future endometriosis therapy.     

Immobilization of Pt Nanoparticles via Rapid and Reusable Electropolymerization of Dopamine on TiO2 Nanotube Arrays for Reversible SERS Substrates and Nonenzymatic Glucose Sensors

Inspired by mussel‐adhesion phenomena in nature, polydopamine (PDA) coatings are a promising route to multifunctional platforms for decorating various materials. The typical self‐polymerization process of dopamine is time‐consuming and the coatings of PDA are not reusable. Herein, a reusable and time‐saving strategy for the electrochemical polymerization of dopamine (EPD) is reported. The PDA layer is deposited on vertically aligned TiO₂ nanotube arrays (NTAs). Owing to the abundant catechol and amine groups in the PDA layer, uniform Pt nanoparticles (NPs) are deposited onto the TiO₂ NTAs and can effectively prevent the recombination of electron–hole pairs generated from photo‐electrocatalysis and transfer the captured electrons to participate in the photo‐electrocatalytic reaction process. Compared with pristine TiO₂ NTAs, the as‐prepared Pt@TiO₂ NTA composites exhibit surface‐enhanced Raman scattering sensitivity for detecting rhodamine 6G and display excellent UV‐assisted self‐cleaning ability, and also show promise as a nonenzymatic glucose biosensor. Furthermore, the mussel‐inspired electropolymerization strategy and the fast EPD‐reduced nanoparticle decorating process presented herein can be readily extended to various functional substrates, such as conductive glass, metallic oxides, and semiconductors. It is the adaptation of the established PDA system for a selective, robust, and generalizable sensing system that is the emphasis of this work.