摘要：作为新一代宽禁带半导体，氧化镓因具有更大的禁带宽度（4.4～4.8 eV）和更高的击穿场强（8 MV/cm）,成为制备耐高压、高频、高功率电力电子器件的最佳候选材料。然而，氧化镓肖特基二极管具有终端电场边缘集中效应，导致器件因提前击穿而失效，从而限制了氧化镓的应用。本文通过将可以缓解电场边缘集中效应的高阻区和抑制反向漏电的电子势垒层相结合，设计了一种新型复合终端。仿真结果表明：引入高阻区终端结构的器件电极边缘附近的峰值电场从3.650 MV/cm下降到0.246 MV/cm,可以有效缓解电极电场边缘集中效应。当高阻区Mg离子注入浓度为1019cm-3时，击穿电压从725 V提高到2 115 V,巴利加优值从0.060 GW/cm2增加到0.247 GW/cm2,临界击穿场强从3.650 MV/cm提升到5.500 MV/cm,提高了50.7%;与此同时，电子势垒层AlN的引入使器件反向漏电流大幅降低，反向击穿电压提升至2 690 V。该新型复合终端结构不仅可以有效抑制器件的反向漏电流，同时可以有效提升器件的反向击穿电压。本研究为耐高压、低反向漏电流氧化镓肖特基二极管的研制提供了理论基础。

摘要：针对高温、腐蚀等复杂条件下的真空测试需求,提出了一种基于4H-SiC为敏感材料且可批量制造的微型化差分电容式真空计。通过有限元仿真分析,研究了力学敏感结构、电容结构等对传感器灵敏度及非线性度的影响。传感器敏感单元由圆形敏感膜与“开口型”双电容结构构成。仿真结果表明:该差分电容式敏感结构与单电容式结构相比,在0~1000 Pa测压范围内,灵敏度仅下降0.02 fF/Pa,非线性度从0.92%降低至0.37%,可为复杂环境下的真空压力测试提供可行的技术支撑。

摘要：Objective:Pediatric cancer patients endure multiple symptoms during treatment and also in *** health technologies provide an innovative way to support their symptom *** review aimed to examine the effect of digital health technologies on managing symptoms among across pediatric cancer ***:A systematic literature search of six English and three Chinese electronic databases was combined with hand searching,to identify eligible research studies from database establishment to November 30,*** reviewers carried out data selection,data extraction,and quality appraisal independently.A narrative approach was taken to summarize ***:Four randomized control trials,two quasi-experiments,and five one group pre-posttest designed studies,were included in the review with a total of 425 *** methodological quality of the studies was generally *** symptoms(anxiety,depression,pain,anger,fatigue,fear,distress)and seven digital health technologies(visual reality,website,humanoid robot,app,wearable devices,short messages and videoconference)were reported in the included ***:Current evidence supports the effect of digital health technologies is generally mixed and *** is a trend of positive effects found in the interventions that feature digital health technologies’interactive *** review highlights the need for further investigation with rigorous research designs and the consideration of influencing factors from the symptoms,participants,and context levels to inform a better digital health implementation.

摘要：针对数控机床可控励磁直线同步电动机磁悬浮系统的强非线性、外部扰动不确定性的问题,设计基于RBF神经网络直接自适应控制器。通过分析磁悬浮系统的运行机理,推导运动方程及悬浮力方程,进而建立系统的状态方程;用悬浮高度的跟踪误差和误差的变化量构造误差函数,设计直接自适应理想控制器并采用RBF神经网络对其进行逼近;设计自适应律来估计神经网络理想权值,对误差函数的变化率构造二次型Lyapunov函数,利用Lyapunov稳定性理论来证明系统稳定;通过Matlab对控制系统进行计算机仿真,结果表明该方法设计的控制器与自适应模糊滑模控制器和PID控制器相比,空载启动时调节时间减少了23.5%,突加负载时动态降落减少了64.7%,恢复时间减少了38.2%,具有稳态误差小,调节时间和恢复时间短,抗扰性较强的优点,能有效提高磁悬浮系统的控制性能。

摘要：Single-atom Pt catalysts are designed to promote efficient atom utilization,whereas effective decrease of Pt loading and improvement of photocatalytic activity in monoatomic Pt-deposited systems is still *** dispersed metal species in crystalline carbon nitride are still challenging owing to their high crystallization and structural *** this study,we developed a novel single-atomic Pt-Cu catalyst for reducing noble metal loading by combining Pt with earth-abundant Cu atoms and enhancing photocatalytic CO_(2)reduction.N-vacancy-rich crystalline carbon nitride was used as a fine-tuning ligand for isolated Pt-Cu atom dispersion based on its accessible functional N vacancies as the seeded *** synthesized dimetal Pt-Cu atoms on crystalline carbon nitride(Pt Cu-cr CN)exhibited high selectivity and activity for CO_(2)conversion without the addition of any cocatalyst or sacrificial *** particular,we demonstrated that the diatomic Pt-Cu exhibited high mass activity with only 0.32 wt% Pt loading and showed excellent photocatalytic selectivity toward CH_(4)*** mechanism of CO_(2)photoreduction for Pt Cu-cr CN was proposed based on the observations and analysis of aberration-corrected high-angle annular dark-field scanning transmission electron microscopy images,in situ irradiated X-ray photoelectron spectroscopy,and in situ diffuse reflectance infrared Fourier transform *** findings of this work provide insights for abrogating specific bifunctional atomic metal sites in noble metal-based photocatalysts by reducing noble metal loading and maximizing their effective mass activity.

摘要：The controller design and digital simulation for the hyper velocity kinetic energy missile is investigated. A mathematical model of the trajectory deviation from the line of sight was established, the guidance closed loop was compensated with a phase advance lag corrective network, a selecting algorithm of the attitude control motors used to steer the missile's attitude was presented. In the presence of a wide variety of disturbances the results of digital simulation are satisfactory to circular error probability(CEP) being less than 0 5?m. The steering scheme utilizing attitude control motors as actuators to control the attitude of the missile is feasible.

摘要：[目的]TCM100型轨道电路在我国首次应用于深圳地铁4号线和广州地铁8号线。在设备维保初期发现,原TCM(轨道电路模块)组的供电方式存在一定弊端,更换单个TCM将影响多个轨道区段的功能与显示,且更换TCM时设备故障频发,有必要对TCM100型轨道电路进行改造。[方法]通过对TCM100型轨道电路中的TCM组研究,指出了西门子股份公司提供的《TCM维护手册》以及TCM供电方式设计中存在的问题,并提出了一种TCM100型轨道电路改造方案。依托某车辆段试车线,对改造后的TCM100型轨道电路进行了TCM更换试验。[结果及结论]TCM100型轨道电路的改造方案如下:将原正极线所接的单个万可接线端子替换为3个带空气开关的万可接线端子,分别控制3个TCM的正极供电,负极供电不做变更,从而实现单个模块的独立供电。TCM更换试验确定了最优的更换方式,证明了该型轨道电路改造方案的有效性。

摘要：With the fast development of nanotechnology,reactive engineered nanomaterials(ENMs)are increasingly discharged into the environment,where they interact with environmental components and organisms and thus pose potential *** interactions-derived formation of nano-environmental and nano-bio interfaces determines environmental behaviors and biological effects of ENMs,and ubiquitous dissolved organic matter(DOM)is bound to impact the interfacial interactions and the resulted environmental ***,we systematically investigated adsorptive interactions between ENMs and various DOM representatives,and thereby demonstrated the effects of DOM on the aqueous suspension/aggregation,mobility in porous media,adsorption of contaminants,transformation,and biological accumulation and toxicity of ***,we conclude that natural DOM can in general expand environmental distribution of ENMs while limit their toxicity to organisms.

摘要：现代健康理念拓展了步行环境内涵,亟待探索面向健康促进的步行环境设计理论与方法。基于国内外步行理论思考和实践总结,辨析整体健康理念的演变,厘清了步行环境与健康之间的关联因素,提出从区域交通、步行需求和环境体验3个层次构建健康促进的支持性步行环境设计理论框架。通过苏州环古城河步行道改造设计案例实证研究表明,从“交通体系、空间特色、服务设施、景观质量”四方面进行步行环境改造设计,将片段化景观打造成完善的健康支持体系,有效实现环境健康、个体健康与社会健康的良性循环,全面提升城市公共健康和环境品质。

摘要：针对传统幂次趋近律存在的抖振以及全局收敛缓慢的问题,提出一种新型复合滑模趋近律,该趋近律通过引入正切函数以及对传统幂次趋近律的改进,实现趋近律的快速收敛和无抖振特性.首先,引入正切函数,在初始状态已知的情况下使系统更快地收敛;其次,通过设计的趋近律改进传统幂次趋近律中含符号函数乘积项容易引起的抖振;然后,理论证明新型复合趋近律能够快速收敛且无抖振,并推导出趋近速率及稳态误差界;最后,以直线磁悬浮同步电动机磁悬浮系统为例,与双幂次趋近律和多幂次趋近律仿真对比,进一步验证新型复合趋近律能够明显缩短系统的动态过程并消除抖振,且存在模型不确定性及外加干扰作用下,系统仍能迅速地收敛到平衡点附近的领域内.