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关键词： Electrolyte-gated organic field-effect transistor   crystallization   electrical double layer   molecular dynamics   solid-liquid interface  

摘要： Quantitative measurements of molecular dynamics at the solid-liquid interface are of crucial importance in a wide range of fields, such as heterogeneous catalysis, energy storage, nanotluidics, biosensing, and crystallization. In particular, the molecular dynamics associated with nucleation and crystal growth is very challenging to study because of the poor sensitivity or limited spatial/temporal resolution of the most widely used analytical techniques. We demonstrate that electrolyte-gated organic field-effect transistors (EGOFETs) are able to monitor in real-time the crystallization process in an evaporating droplet. The high sensitivity of these devices at the solid-liquid interface, through the electrical double layer and signal amplification, enables the quantification of changes in solute concentration over time and the transport rate of molecules at the solid-liquid interface during crystallization. Our results show that EGOFETs offer a highly sensitive and powerful, yet simple approach to investigate the molecular dynamics of compounds crystallizing from water.

摘要： In recent years, more and more proposals have been explored to replace conventional SRAM, DRAM, and Flash with novel memories. Moreover, the performance gap between data access latency over a memory bus and high-speed processing continues to grow. Domain Wall Memory (DWM)-aka Racetrack Memory-is a spintronic memory that stores multiple data bits in a ferromagnetic nanowire and shifts this data into alignment with one or few access ports to read/write the data. DWM is non-volatile, highly dense (1-4F 2 per cell), extremely energy efficient (circa 0.1pJ per write), low latency (circa 1ns per access), and does not suffer from endurance limitations. Domain Wall Memory can serve as an ideal conventional memory/storage replacement throughout the memory hierarchy from cache replacement to main memory. DWM's main drawback is the latency, energy, and potential reliability concern from shifting data to align with access points. However, this structure also permits a novel recently proposed access mode called a Transverse Read (TR), which determines the number of '1's between two access points without pin-pointing their location. This dissertation leverages TR to first propose two new reliability schemes that address misalignment and data loss in DWM due to pinning while shifting. Second, a TR-based Processing-In-Memory (PIM) architecture is proposed that boasts multi-operand bulk-bitwise operations, logical shifting and rotation, multi-operand addition, two operand multiplication, and dense accumulators. The arithmetic operations are shown for Integer/fixed-point and floating-point fidelities. Third, targeting DWM in size, weight, and power (SWaP) constrained architectures such as edge systems multiple applications of DWM PIM are explored including machine learning inference and training for hyperdimensional computing, convolutional neural networks. The proposed reliability improvements offer 10's of years of fault free operation with energy savings and protection over new fa

关键词： Entropy production   Nonequilibrium & irreversible thermodynamics   Open quantum systems   Quantum master equation   Quantum stochastic processes   Quantum thermodynamics   Information theory  

摘要： The thermodynamic and kinetic uncertainty relations indicate trade-offs between the relative fluctuation of observables and thermodynamic quantities such as dissipation and dynamical activity. Although these relations have been well studied for classical systems, they remain largely unexplored in the quantum regime. In this Letter, we investigate such trade-off relations for Markovian open quantum systems whose underlying dynamics are quantum jumps, such as thermal processes and quantum measurement processes. Specifically, we derive finite-time lower bounds on the relative fluctuation of both dynamical observables and their first passage times for arbitrary initial states. The bounds imply that the precision of observables is constrained not only by thermodynamic quantities but also by quantum coherence. We find that the product of the relative fluctuation and entropy production or dynamical activity is enhanced by quantum coherence in a generic class of dissipative processes of systems with nondegenerate energy levels. Our findings provide insights into the survival of the classical uncertainty relations in quantum cases.

关键词： 超表面   手性   太赫兹  

摘要： 手性物质对入射的左右旋圆偏振光表现出不同的相互作用,表现为圆二色性和光学活性.经过特殊设计的二维和三维手性超材料能够表现出比天然材料大得多的手性响应.近日,研究人员通过引入非手性超原子间的破坏性干涉提出了一种新型的全硅手性超表面.基于自旋解耦的设计原则,他们展示了高效的圆二色性产生和手性波前调控.这种灵活、高效的手性超表面实现方案可以为手性器件的发展带来新的思路.

关键词： 并矢格林函数法   奇异项   L类矢量波函数   无旋场   本征模式  

摘要： 鉴于部分文献关于电型并矢格林函数在矩形波导中的表达式存在缺项.;本文用磁型和电型并矢格林函数法对矩形波导电型并矢格林函数表达式做了详细推证,对缺项产生的来源从几方面做了分析,最后写出了该表达式的完整形式.

关键词： 急性脑血管病   磁共振扩散加权成像   动脉自旋标记   应用价值  

摘要： 目的探讨急性脑血管病诊断中磁共振扩散加权成像(magnetic resonance diffusion-weighted imaging,DWI)与动脉自旋标记(arterial spin labeling,ASL)的应用价值。方法选取云南中医药大学第二附属医院医学影像科2019年7月至2020年8月收治的疑似急性脑血管病患者82例,均给予ASL和DWI。分析同时间段病灶中心与健侧相应部位表观扩散系数(ADC)值、病变信号特征变化、ASL和DWI的灵敏度和特异度。结果82例患者中,患侧6 h内、6~24 h、24~48 h及平均值ADC值均低于健侧,差异有统计学意义(P<0.05);健侧与患侧6 h、6~24 h、24~48 h及平均值ADC值,差异无统计意义(P>0.05);所有患者中CASL-PWI低灌注区比DWI的异常信号区大的患者共有47例,而CASL-PWI低灌注区比DWI的异常信号区小的患者共有32例,2种变化信号相等患者6例;DWIPWI,差异有统计学意义(P<0.05);DWI=PWI患者中DWI、PWI病变面积均大于DWI>PWI,差异有统计学意义(P<0.05);联合检查灵敏度与特异度高于单纯使用磁共振扩散加权成像与动脉自旋标记检查,差异有统计学意义(P<0.05)。结论急性脑血管病诊断中,磁共振扩散加权成像与动脉自旋标记检查均有较好的效果,但是联合使用效果更好。

关键词： 理论物理学家   原子模型   量子物理   德布罗意   黑体辐射   光电效应   物质波   未来前景  

摘要： 量子力学中反映不确定性的概率究竟是怎么来的呢?物理与哲学探索的都是世界的本源问题,物理学家往往又是伟大的哲学家。著名理论物理学家Steven Weinberg从2016年开始,就表达了他作为一个资深物理学家对量子物理未来前景的困惑和担忧。普朗克解决黑体辐射难题,爱因斯坦解释光电效应,玻尔的原子模型'德布罗意的物质波和薛定铐的波动方程。