面向Si/SiC混合器件逆变器全寿命周期安全工作区的多开关模式主动切换策略

基于硅基绝缘栅双极型晶体管(Si IGBT)和碳化硅金属氧化物半导体场效应管(SiC MOSFET)的Si IGBT/SiC MOSFET混合器件采用多开关模式切换策略可使变换器具备应对复杂工况的能力,然而现有切换策略并未考虑器件疲劳老化对模式切换阈值电流的影响,在混合器件老化进程后期极有可能造成器件热失效,进而严重威胁变换器的可靠运行。基于此,提出了一种面向Si/SiC混合器件逆变器全寿命周期安全工作区的多开关模式主动切换策略。基于器件疲劳老化对逆变器最大安全运行电流的影响规律,设计了考虑老化进程的逆变器安全工作区刻画流程。根据安全工作区刻画结果,提出了适用于混合器件全寿命周期的多开关模式主动切换策略。实验结果表明,该策略能够针对混合器件不同老化程度来动态调整开关模式切换阈值电流,从而在器件全寿命周期内保障逆变器的运行可靠性。     

基于抑制环流的自适应下垂控制改进策略

在孤岛模式下的微电网中由于线路阻抗存在差异,采用传统下垂控制的逆变器不仅无法精确分配负载功率,还会产生环流。为解决该问题,提出了一种基于抑制环流的自适应下垂控制改进策略。该策略采用旋转坐标的环流来构造虚拟阻抗,通过PI控制使线路等效阻抗不断相向趋近直至相等,从而均衡分配负载功率。所提出的改进策略无需实时检测线路阻抗,也无需借助通信网络。此外,构造的虚拟阻抗不仅能有效抑制环流,还不会引起输出电压大幅跌落。仿真结果验证了改进控制策略的有效性。     

基于显著性检测的星载嵌入式跟踪系统

随着航天科技的不断发展,计算机视觉算法在卫星上的应用方兴未艾,为了实现更多的功能需求和应对可能的威胁,视觉目标跟踪作为其中基础但具有挑战性的任务更是至关重要。然而,目前已有的目标跟踪算法大多数算法只限于对图像序列进行跟踪。另一方面,受到硬件条件制约,很多优秀的算法因为复杂度较高很少被应用到星载嵌入式系统中。这些目标跟踪算法运行时,通常需要人为地给出目标的边界框。为了自动得到边界框,需要目标检测算法对输入图像进行运动目标检测。本文提出了一种基于显著性检测和相关滤波的单目标检测与跟踪一体化算法,并与嵌入式系统相结合,在搭载的TMS320C6678芯片上达到了2 048 pixel×2 048 pixel分辨率下24 fps的帧率。具体地,检测算法负责对图像进行预处理并获得边界框,然后目标跟踪算法给出目标在后续帧中的位置。为了验证算法在实际跟踪中的有效性,本研究搭建了一个由相机、DSP和云台组成的光学平台并进行了实验验证。在该系统中,DSP自动完成检测、跟踪、驱动云台和再检测任务,达到了很好的检测跟踪效果。     

基于需求侧博弈的区域综合能源服务商最优运营策略

为了提高综合能源服务商运营服务的高效性、清洁性和经济性,提出了一种基于需求侧博弈的综合能源服务商最优运营策略。通过对综合能源服务商模型的分析,以用户能源消耗量确定系统碳排放量,建立了区域综合能源服务商碳排放模型,确定了园区的碳排放量。在此基础上,考虑了用户对用能成本波动的可承受能力和服务商应对用户用能变化的风险成本,分别以综合能源服务商全天利润最大、用户用能成本最小为目标函数,建立了综合能源服务商-多用户博弈优化模型。采用迭代搜索法得到纳什均衡解,从而确定服务商最优运营策略。最后以典型工业园区为例对所提策略进行仿真验证。结果表明,所研究的服务商运营策略有效降低了系统碳排放量,提高了综合能源服务商的经济效益和用户满意度。     

A multi-energy inertia-based power support strategy with gas network constraints

An integrated energy system with multiple types of energy can support power shortages caused by the uncertainty of renewable energy. With full consideration of gas network constraints, this paper proposes a multi-energy inertia-based power support strategy. The definition and modelling of gas inertia are given first to demonstrate its ability to mitigate power fluctuations. Since partial utilization of gas inertia can influence overall gas network parameters, the gas network is modelled with an analysis of network dynamic changes. A multi-energy inertia-based power support model and strategy are then proposed for fully using gas-thermal inertia resources in integrated energy systems. The influence of gas network constraints on strategy, economy and power outputs is analyzed. Special circumstances where the gas network can be simplified are introduced. This improves the response speed and application value. The feasibility and effectiveness of the proposed strategy are assessed using a real scenario.     

Promote Intratumoral Drug Release and Penetration to Counteract Docetaxel-Induced Metastasis by Photosensitizer-Modified Red Blood Cell Membrane-Coated Nanoparticle

The red blood cell membrane (RBCm) provides tight protection, lowers the immunogenicity, and prolongs the circulation time of drugs in vivo when acting as the coating of drug delivery systems. However, the cellular uptake and release of drugs are hindered by RBCm. Docetaxel (DTX) is the first-line medicine for treating triple-negative breast cancer (TNBC), but it induces tumor metastasis. To solve these dilemmas, in this study, the photosensitizer 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide (DiR)-modified RBCm (DM) is prepared, which is coated onto a hybrid micelle consisting of the prodrugs of DTX and the anti-metastasis agent calcitriol (CTL), obtaining a nanoparticle, named HDC-DM. In a 4T1 tumor-bearing mouse model, after injecting HDC-DM, the intratumoral DTX and CTL concentrations are increased by 1.7 and 2.5 times compared with the free drug groups. After irradiating tumors with near-infrared laser, DiR elicits the photothermal effect, triggering the rupture of RBCm and drug release, promoting drug penetration in tumors, and inducing immunogenic cell death. The tumor growth inhibition rate is 77%, and the formation of lung metastases is reduced by 82%, with good biocompatibility. It is suggested that the combination of phototherapy, chemotherapy, and anti-metastatic therapy using HDC-DM is expected to be a powerful strategy for treating TNBC.     

Challenges and Opportunities of Implantable Neural Interfaces: From Material,Electrochemical and Biological Perspectives

The desirable implantable neural interfaces can accurately record bioelectrical signals from neurons and regulate neural activities with high spatial/time resolution, facilitating the understanding of neuronal functions and dynamics. However, the electrochemical performance (impedance, charge storage/injection capacity) is limited with the miniaturization and integration of neural electrodes. The “crosstalk” caused by the uneven distribution of elctric field leads to lower electrical stimulation/recording efficiency. The mismatch between stiff electrodes and soft tissues exacerbates the inflammatory responses, thus weakening the transmission of signals. Though remarkable breakthroughs have been made through the incorporation of optimizing electrode design and functionalized nanomaterials, the chronic stability, and long-term activity in vivo of the neural electrodes still need further development. In this review, the neural interface challenges mainly on electrochemistry and biology are discussed, followed by summarizing typical electrode optimization technologies and exploring recent advances in the application of nanomaterials, based on traditional metallic materials, emerging 2D materials, conducting polymer hydrogels, etc., for enhancing neural interfaces. The strategies for improving the durability including enhanced adhesion and minimized inflammatory response, are also summarized. The promising directions are finally presented to provide enlightenment for high-performance neural interfaces in future, which will promote profound progress in neuroscience research.     

基于用户行为的社交网络人格特质识别方法

社交网络已成为人们获取和发布信息的一个重要平台,也是黑客发起网络诈骗的主要场地。大多数黑客在发起网络诈骗之前,首先会判别目标用户的主要人格特点,然后根据主要人格特点制定与其接触的策略。因此,面向社交网络用户的人格特质识别方法的研究对提高用户识别社交网络诈骗能力具有重要意义。提出基于用户的人格特质识别方法。通过构建面向社交网络的人格特质词典提取用户发表或转发文本信息中能反映用户主要人格特质类型的观测值,采用5个具有不同参数值的隐半马尔可夫模型刻画用户在社交网络上发表或转发文本信息的行为过程。在人格特质识别阶段,通过计算每个用户在发表或转发文本信息过程中产生的观测序列相对于模型的平均对数似然概率,以识别用户所属的人格特质类型。在采集的新浪微博数据集上进行实验,结果表明,当假正率为10%时,该方法的总真正率为93.18%,能准确识别用户的人格特质类型。     

Hydrofluoric Acid-Removable Additive Optimizing Electrode Electrolyte Interphases with Li+ Conductive Moieties for 4.5 V Lithium Metal Batteries

High-voltage lithium metal batteries (LMBs) are capable to achieve the increasing energy density. However, their cycling life is seriously affected by unstable electrolyte/electrode interfaces and capacity instability at high voltage. Herein, a hydrofluoric acid (HF)-removable additive is proposed to optimize electrode electrolyte interphases for addressing the above issues. N, N-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) aniline (DMPATMB) is used as the electrolyte additive to induce PF₆⁻ decomposition to form a dense and robust LiF-rich solid electrolyte interphase (SEI) for suppressing Li dendrite growth. Moreover, DMPATMB can help to form highly Li⁺ conductive Li₃N and LiBO₂, which can boost the Li⁺ transport across SEI and cathode electrolyte interphase (CEI). In addition, DMPATMB can scavenge traced HF in the electrolyte to protect both SEI and CEI from the corrosion. As expected, 4.5 V Li|| LiNi_0.6Co_0.2Mn_0.2O₂ batteries with such electrolyte deliver 145 mAh g⁻¹ after 140 cycles at 200 mA g⁻¹. This work provides a novel insight into high-voltage electrolyte additives for LMBs.     

Grafted MXenes Based Electrolytes for 5V-Class Solid-State Batteries

Polymer blends based solid polymer electrolytes (SPEs), combining the advantages of multiple polymers, are promising for the utilization of 5 V-class cathodes (e.g., LiCoMnO₄ (LCMO)) with enhanced safety. However, severe macro-phase separation with defects and voids in polymer blends restrict the electrochemical stability and ionic migration of SPEs. Herein, inorganic compatibilizer polyacrylonitrile grafted MXene (MXene-g-PAN) is exploited to improve the miscibility of the poly(vinylidene fluoride-co-hexafluoropropylene) (PVHF)/PAN blends and suppress the consolidation of phase particles. The resulting SPE exhibits a high anodic stability with an ionic conductivity of 2.17 × 10⁻⁴ S cm⁻¹, enabling a stable and reversible Li platting/stripping (over 2500 h). The fabricated solid Li‖LCMO cell delivers a 5.1 V discharge voltage with a decent capacity (131 mAh g⁻¹) and cycling performance. Subsequently, the solid all-in-one graphite‖LCMO battery is also constructed to extend the application of MXene based SPEs in flexible batteries. Benefiting from the interface-less design, outstanding mechanical flexibility and stability is achieved in the battery, which can endure various deformations with a low-capacity loss (< ≈10%). This study signifies a significant development on solid flexible lithium ion batteries with enhanced performance, stability, and reliability by investigating the miscibility of polymer blends, benefiting for the design of high-performance SPEs.