用数据处理的方法消除扫速不稳对OCT图像的影响

建立了一个光纤结构的扫描延时的光学相关层析成像(OCT)系统。扫描平台速度不稳会影响成像质量。介绍了用付立叶变换方法将采样信号转换到频域处理的过程中,合理选择信号频域分布的质心位置和频带宽度等参数,可消除由于扫速不稳造成的图像失真。     

A 2-D analytical solution for SCEs in DG MOSFETs

A two-dimensional (2-D) analytical solution of electrostatic potential is derived for undoped (or lightly doped) double-gate (DG) MOSFETs in the subthreshold region by solving Poissons equation in a 2-D boundary value problem. It is shown that the subthreshold current, short-channel threshold voltage rolloff and subthreshold slope predicted by the analytical solution are in close agreement with 2-D numerical simulation results for both symmetric and asymmetric DG MOSFETs without the need of any fitting parameters. The analytical model not only provides useful physics insight into short-channel effects, but also serves as basis for compact modeling of DG MOSFETs.     

热电Ca3Co4O9薄膜的一致取向生长及其激光感生电压效应

利用脉冲激光沉积(PLD)法,在蓝宝石(0001)平衬底上成功制备了c轴一致取向的Ca3Co4O9薄膜。利用X射线衍射(XRD)分析测定了薄膜的相结构和生长取向。研究了不同衬底温度与不同原位氧压对Ca3Co4O9薄膜结晶质量与生长取向的影响,确定了最佳生长条件。利用这一条件在倾斜Al2O3(0001)衬底上制备了Ca3Co4O9薄膜。研究发现,当Ca3Co4O9薄膜被波长248nm,脉冲宽度20ns的脉冲激光照射时,在薄膜两端存在较大的激光感生热电电压(LITV)信号,峰值电压达到4.4V,其上升沿为36ns,半峰全宽(FWHM)为131ns。可以认为这种激光感生热电电压信号是由于Ca3Co4O9薄膜面内与面间泽贝克(Seebeck)系数张量的各向异性引起的。     

基于决策树的雷达型号识别方法

从信息论的角度,以平时侦察所得各种雷达参数的信息量作为分类依据,得出一种基于决策树算法的雷达型号识别方法。计算机仿真试验表明,在目标种类不是太多的情况下,即使仅能侦察少量的雷达特征参数,通过侦察次数的积累,本算法仍能得到不断改善的识别结果,具有一定的实际意义。     

Sufficient Utilization of Mn2+/Mn3+/Mn4+ Redox in NASICON Phosphate Cathodes towards High-Energy Na-Ions Batteries

Na superionic conductor of Na₃MnTi(PO₄)₃ only containing high earth-abundance elements is regarded as one of the most promising cathodes for the applicable Na-ion batteries due to its desirable cycling stability and high safety. However, the voltage hysteresis caused by Mn²⁺ ions resided in Na⁺ vacancies has led to significant capacity loss associated with Mn reaction centers between 2.5–4.2 V. Herein, the sodium excess strategy based on charge compensation is applied to suppress the undesirable voltage hysteresis, thereby achieving sufficient utilization of the Mn²⁺/Mn³⁺ and Mn³⁺/Mn⁴⁺ redox couples. These findings indicate that the sodium excess Na_3.5MnTi_0.5Ti_0.5(PO₄)₃ cathode with Ti⁴⁺ reduction has a lowest Mn²⁺ occupation on the Na⁺ vacancies in its initial composition, which can improve the kinetics properties, finally contributing to a suppressed voltage hysteresis. Based on these findings, it is further applied the sodium excess route on a Mn-richer phosphate cathode, which enables the suppressed voltage hysteresis and more reversible capacity. Consequently, this developed Na_3.6Mn_1.15Ti_0.85(PO₄)₃ cathode achieved a high energy density over 380 Wh kg⁻¹ (based on active substance mass of cathode) in full-cell configurations, which is not only superior to most of the phosphate cathodes, but also delivers more application potential than the typical oxides cathodes for Na-ion batteries.     

Incombustible Polymer Electrolyte Boosting Safety of Solid-State Lithium Batteries: A Review

Lithium-ion batteries with their portability, high energy density, and reusability are frequently used in today's world. Under extreme conditions, lithium-ion batteries leak, burn, and even explode. Therefore, improving the safety of lithium-ion batteries has become a focus of attention. Researchers believe using a solid electrolyte instead of a liquid one can solve the lithium battery safety issue. Due to the low price, good processability and high safety of the solid polymer electrolytes, increasing attention have been paid to them. However, polymer electrolytes can also decompose and burn under extreme conditions. Moreover, lithium dendrites are formed continuously due to the uneven charge distribution on the surface of the lithium metal anode. A short circuit caused by a lithium dendrite can cause the battery to thermal runaway. As a result, the safety of polymer solid-state batteries remains a challenge. In this review, the thermal runaway mechanism of the batteries is summarized, and the batteries abuse test standard is introduced. In addition, the recent works on the high-safety polymer electrolytes and the solution strategies of lithium anode problems in polymer batteries are reviewed. Finally, the development direction of safe polymer solid lithium batteries is prospected.     

基于STM32的航空通信总线切换器设计

ARINC429是目前最常用的一种航空通信总线,它具有简单有效,性能可靠等特性。利用ARINC429总线,飞控系统同各机载设备进行通信,但不同设备上并非都采用ARINC429接口,如卫星接收机采用RS 422总线,且飞控系统ARINC429接口有限。为解决这一问题,提出了基于STM32的航空通信总线切换器设计,方案选取了意法半导体的STM32微控制器,具有高度一体化,低功耗,处理速度快,方便调试与后续开发等优点。     

基于MSP430的动感单车测速系统设计

主要论述了MSP430F149低功耗单片机TIMER A捕获方式的工作原理、霍尔传感器的工作方式,利用MSP430F149单片机捕获方式和霍尔传感器A44E设计了动感单车的速度测量系统,同时给出了较为精确的计算方法以及程序设计过程。     

一种基于二维细化的自适应信号捕获算法

该文针对低信噪比(SNR)情况下信号捕获精度较低的问题提出一种基于伪码相位和载波频率的2维细化自适应捕获算法,该算法根据信号强度自适应调整频率步进值和捕获门限,首先对伪码相位和载波频率进行粗捕,在此基础上对捕获到的伪码相位方格和载波频率方格进行细化,再对伪码相位和载波频率进行细捕以提高捕获精度。该文对算法进行了理论分析和仿真验证,结果表明,该算法能提高捕获的伪码相位分辨率和载波频率分辨率,有效提高检测概率,适用于低信噪比和高精度要求下的信号快速捕获。