Achieving 1.2 fm/Hz^(1/2)Displacement Sensitivity with Laser Interferometry in Two-Dimensional Nanomechanical Resonators:Pathways towards Quantum-Noise-Limited Measurement at Room Temperature

Laser interferometry is an important technique for ultrasensitive detection of motion and displacement.We push the limit of laser interferometry through noise optimization and device engineering.The contribution of noises other than shot noise is reduced from 92.6%to 62.4%,demonstrating the possibility towards shotnoise-limited measurement.Using noise thermometry,we quantify the laser heating effect and determine the range of laser power values for room-temperature measurements.With detailed analysis and optimization of signal transduction,we achieve 1.2 fm/Hz^(1/2)displacement measurement sensitivity at room temperature in twodimensional(2D)Ca Nb_(2)O_(6)nanomechanical resonators,the best value reported to date among all resonators based on 2D materials.Our work demonstrates a possible pathway towards quantum-noise-limited measurement at room temperature.

Liquid-phase esterification of methacrylic acid with methanol catalyzed by cation-exchange resin in a fixed bed reactor:Experimental and kinetic studies

The kinetic behavior of esterification between methacrylic acid and methanol catalyzed by NKC-9 resin was studied in a fixed bed reactor.The reaction was conducted in the temperature range of 323.15 to 368.15 K with the molar ratio of reactants from 0.8 to 1.4 under certain pressure.The measurement data were regression with the pseudo-homogeneous(P-H),Eley-Rideal(E-R),and Langmuir-Hinshelwood(L-H)heterogeneous kinetic models.Independent adsorption experiments were implemented to gain the adsorption equilibrium constants of four components.Among the above three models,the L-H model exhibited the best fitting results.The stability of NKC-9 was evaluated by long-term running with the yield of methyl methacrylate no decrease during 3000 h operation.The structure and physicochemical properties of the new and used catalyst were performed by several characterizations including thermogravimetric analysis(TG),scanning electron microscope(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)and so on.

Broad-range,high-linearity,and fast-response pressure sensing enabled by nanomechanical resonators based on 2D non-layered material:β-In_(2)S_(3)

Two-dimensional(2D)non-layered materials,along with their unique surface properties,offer intriguing prospects for sensing applications.Introducing mechanical degrees of freedom is expected to enrich the sensing performances of 2D non-layered devices,such as high frequency,high tunability,and large dynamic range,which could lead to new types of high performance nanosensors.Here,we demonstrate 2D non-layered nanomechanical resonant sensors based onβ-In_(2)S_(3),where the devices exhibit robust nanomechanical vibrations up to the very high frequency(VHF)band.We show that such device can operate as pressure sensor with broad range(from 103 Torr to atmospheric pressure),high linearity(with a nonlinearity factor as low as 0.0071),and fast response(with an intrinsic response time less than 1μs).We further unveil the frequency scaling law in theseβ-In_(2)S_(3) nanomechanical sensors and successfully extract both the Young's modulus and pretension for the crystal.Our work paves the way towards future wafer-scale design and integrated sensors based on 2D non-layered materials.

PDGFRB mutation causes intracranial aneurysm

Intracranial aneurysm(IA)is characterized by defects in the middle muscular layer and pathological dilatation of cerebral arteries.The rupture of IA,resulting in aneurysmal subarachnoid hemorrhage,poses a substantial public health problem,especially in developed countries,due to its high mortality,morbidity,and socioeconomic burden(Bakker and Ruigrok,2021).Understanding the risk factors for IA is critical for disease prevention.Although numerous studies(Yan et al.,2015;Santiago-Sim et al.,2016;Barak et al.,2021;Liu et al.,2021)have highlighted familial aggregation of IA and identified candidate genes such as ADAMTS15,THSD1,ANK3,and PPIL4,the mechanisms underlying IA formation and rupture remain unclear.

On-chip mechanical computing:status,challenges,and opportunities

With increasing challenges towards continued scaling and improve-ment in performance faced by electronic computing,mechanical com-puting has started to attract growing interests.Taking advantage of the mechanical degree of freedom in solid state devices,micro/nano-electromechanical systems(MEMS/NEMS)could provide alternative solutions for future computing and memory systems with ultralow power consumption,compatibility with harsh environments,and high reconfigurability.In this review,MEMS/NEMS-enabled memories and logic processors were surveyed,and the prospects and challenges for future on-chip mechanical computing were also analyzed.

论游戏教学法在对外汉语课堂中的应用——以新西兰惠灵顿地区四所小学为例

本文所讨论的游戏教学法指在对外汉语课堂中,教师针对特定的教学目标,选择适当的内容,采取有趣的形式,组织学生参与其中,使学生在游戏中达到学习语言及文化,并获得积极的情感体验的教学方法.本文通过对新西兰小学汉语课堂游戏的设计、实施及评估三个阶段的分析,探讨了游戏教学法的适用性及有效性.同时,通过案例分析了游戏教学法实施过程中出现的问题,提出了重视动作类游戏、利用电子网络丰富游戏内容、明确游戏设计与实施细则、运用创新游戏促进文化教学等应用策略.