Tuning a Solvation Structure of Lithium Ions Coordinated with Nitrate Anions through Ionic Liquid-Based Solvent for Highly Stable Lithium Metal Batteries

Rational design of promising electrolyte is considered as an effective strategy to improve the cycling stability of lithium metal batteries (LMBs). Here, an elaborately designed ionic liquid-based electrolyte is proposed that is composed of lithium bis(trifluoromethanesulfonyl)imide as the lithium salt, 1-ethyl-3-methylimidazolium nitrate ionic liquid ([EMIm][NO₃] IL) and fluoroethylene carbonate (FEC) as the functional solvents, and 1,2-dimethoxyethane (DME) as the diluent solvent. Using [EMIm][NO₃] IL as the solvent component facilitates a special Li⁺-coordinated NO₃⁻ solvation structure, which enables the continues electrochemical reduction of solvated NO₃⁻ and the formation of remarkably stable and conductive solid electrolyte interface. With FEC as another functional solvent and DME as the diluent solvent, the formulated electrolyte delivers high oxidative stability and ionic conductivity, and endows improved electrochemical reaction kinetics. Therefore, the formulated electrolyte demonstrates exceedingly reversible and stable Li stripping/plating behavior with high average Coulombic efficiency (98.8%) and ultralong cycling stability (3500 h). Notably, the high-voltage Li|LiNi_0.8Co_0.1Mn_0.1O₂ full cell with IL-based electrolyte exhibits enhanced cyclability with a capacity retention of 65% after 200 cycles under harsh conditions of low negative/positive ratio (3.1) and lean electrolyte (2.5 µL mg⁻¹). This study creates the first NO₃⁻-based ionic liquid electrolyte and evokes the avenue for practical high-voltage LMBs.     

IMS域策略与计费控制接口的平滑演进

为了提供更好的基于流的计费和策略控制,3GPP在IMSR7版本中提出策略与计费控制体系架构,其基本思路是将IMSR6版本中的策略决策功能实体和计费策略功能实体合并为R7中的策略与计费规则功能实体。本文首先简要介绍了IMSR6和IMSR7控制模型;然后重点分析了与策略控制、计费控制相关Gx接口、Rx接口的接口消息及其参数。分析表明,通过定义特定AVP,实现了IMSR6向IMSR7策略控制和计费控制接口的平滑演进。     

我国平台经济领域“二选一”现象的成因、影响及对策

“二选一”是我国平台经济领域较为常见的一种竞争策略,其实质是通过排他性交易限制第三方商家的多栖行为。我国平台经济中“二选一”现象的普及程度远超欧美发达国家,其原因包括立法与执法存在不足、线上线下深度融合、特殊的商业模式和市场环境等。从平台间竞争和平台内经营者间竞争两个维度分析了“二选一”行为对竞争的影响机理,提出跨边网络效应、用户转移成本、中小商家数量、平台双重角色等是影响竞争绩效的关键因素,并基于此,进一步提出了治理“二选一”行为的对策建议。     

纳米碳酸锶/高氯酸铵复合粒子的制备及其撞击感度和热分解性能研究

利用超声辅助共沉淀法制备纳米碳酸锶（SrCO₃）,通过溶剂-非溶剂法制备纳米碳酸锶/高氯酸铵（SrCO₃/AP）复合粒子。采用透射电子显微镜、扫描电子显微镜、X射线粉末衍射仪(XRD)分别对纳米SrCO₃的形貌、粒径、晶型和纳米SrCO₃/AP复合粒子的复合效果进行表征。对纯AP和纳米SrCO₃含量分别为2%、4%、6%的SrCO₃/AP复合粒子进行撞击感度测试;采用差示扫描量热仪分别对纯AP、纳米SrCO₃/AP复合粒子和相同比例的纳米SrCO₃与AP的简单混合物进行热分析。通过马弗炉将纳米SrCO₃/AP复合粒子分别在350 ℃和500 ℃下煅烧1 h,对煅烧后的产物作XRD表征,研究纳米SrCO₃的作用机理。结果表明：采用超声辅助共沉淀法制备出的纳米SrCO₃为类球形,粒径在60 nm左右,晶型为斜方晶系;制备出的纳米SrCO₃/AP复合粒子中,微米级的AP表面均匀分布着纳米SrCO₃,纳米SrCO₃的加入会使AP的撞击感度增加;通过两种不同方式添加的纳米SrCO₃均能升高AP的高温分解峰温度,对AP的低温分解没有影响;与纳米SrCO₃和AP的简单混合物相比,纳米SrCO₃/AP复合粒子中AP的高温分解峰值温度升高6.02 ℃,将纳米SrCO₃与AP进行复合后可以提高纳米SrCO₃对AP高温分解的负催化作用。     

微机电陀螺仪技术及其在智能汽车上的应用

通过分析微机电陀螺仪的原理、性能、特点、应用现状和存在问题,认为微振动陀螺、流体陀螺、固体微陀螺、静电悬浮转子式微陀螺最有可能在短期内用于智能汽车系统.考虑到成本、尺寸、精度上的综合优势,提出微振动陀螺、固体陀螺、流体陀螺、静电悬浮陀螺有在智能汽车上推广使用的可能性,而原子陀螺则具有很好的研究前景.     

A survey of neural network accelerator with software development environments

Recent years,the deep learning algorithm has been widely deployed from cloud servers to terminal units.And researchers proposed various neural network accelerators and software development environments.In this article,we have reviewed the representative neural network accelerators.As an entirety,the corresponding software stack must consider the hardware architecture of the specific accelerator to enhance the end-to-end performance.And we summarize the programming environments of neural network accelerators and optimizations in software stack.Finally,we comment the future trend of neural network accelerator and programming environments.     

Video Shot Boundary Detection in MPEG Compressed Sequences Using SVM Learning

A number of automated video shot boundary detection methods for indexing a videosequence to facilitate browsing and retrieval have been proposed in recent years.Among these methods,the dissolve shot boundary isn't accurately detected because it involves the camera operation and objectmovement.In this paper,a method based on support vector machine (SVM) is proposed to detect thedissolve shot boundary in MPEG compressed sequence.The problem of detection between the dissolveshot boundary and other boundaries is considered as two-class classification in our method.Featuresfrom the compressed sequences are directly extracted without decoding them,and the optimal classboundary between two classes are learned from training data by using SVM.Experiments,whichcompare various classification methods,show that using proposed method encourages performance ofvideo shot boundary detection.     

Bubble Architectures for Locally Resonant Acoustic Metamaterials

Soft acoustic metamaterials that embed soft materials in a host media have promising applications in aqueous environments. However, the preparation of soft metamaterials under water and realization of low‐frequency soft acoustic metamaterials remains a challenge. By combining 3D printing technology and surface hydrophobic properties, this work presents a general approach to construct 3D soft acoustic metamaterials using bubbles as resonator units. Low‐frequency broadband locally resonant metamaterials can be realized using patterned bubbles with bandgaps that are orders of magnitude wider than other locally resonant metamaterials. In addition, a water‐to‐air ultratransmission metasurface is prepared by patterning a layer of bubbles beneath the water surface, which allows for the ultratransmission of sound across an air–water interface. This strategy opens up promising avenues for many applications based on locally resonant metamaterials such as deep subwavelength acoustic superlenses or negative‐refraction metamaterials.     

Manipulation of Conductive Domain Walls in Confined Ferroelectric Nanoislands

Conductive ferroelectric domain walls—ultranarrow configurable conduction paths—have been considered as essential building blocks for future programmable domain wall electronics. For applications in high‐density devices, it is imperative to explore the conductive domain walls in small confined systems, while earlier investigations have hitherto focused on thin films or bulk single. Here, an observation and manipulation of conductive domain walls confined within small BiFeO₃ nanoislands aligned in high‐density arrays are demonstrated. Using conductive atomic force microscopy, various types of conductive domain walls, including the head‐to‐head charged domain walls (CDWs), zigzag domain walls, and typical 71° head‐to‐tail neutral domain walls (NDWs), are distinctly visualized. The CDWs exhibit remarkably enhanced metallic conductivity with current of ≈nA order in magnitude and 10⁴ times larger than that inside domains (0.01–0.1 pA), while the semiconducting NDWs allow much smaller current (≈10 pA) than the CDWs. The substantial difference in conductivity for dissimilar walls enables manipulations of various wall conduction states for individual addressable nanoislands via electrical tuning of domain structures. A controllable writing of four distinctive states in individual nanoislands can be achieved, showing application potentials for developing multilevel high‐density memories.     

一种基于紧耦合结构的超宽带天线阵列设计

设计了一种超宽带紧耦合天线阵列,该超宽带天线由两层印刷有偶极子单元的周期结构构成,上层互不相连的偶极子单元为寄生层,下层在E 面增加了强耦合结构的偶极子单元为辐射单元层。馈电网络由Marchaned 巴伦和宽带Wilkinson 功分器组成。仿真结果表明:天线法向辐射时在0.9 GHz ~4.8 GHz 内具有良好的阻抗匹配带宽(VSWR<2),在1 GHz ~4 GHz频段内可以实现E 面60度、H 面45度的扫描范围。该天线具有超带宽、大扫描角、轻薄化等特点,在超宽带小型化相控阵天线中有良好应用前景。