动态心电图报告规范专家共识(2019)

动态心电图作为临床医学的重要无创监测技术,其报告所提供的信息直接关系到临床诊断、治疗和评估的准确性。专家组基于现有循证医学证据及临床经验,起草了动态心电图报告规范,并形成共识。本文介绍了动态心电图报告的注意事项、动态心电信息报告内容、报告编辑、报告格式等。

2020中国动态血压监测指南

高血压是心脑血管疾病的重要危险因素。动态血压监测已成为识别和诊断高血压、评估心脑血管疾病风险、评估降压疗效、指导个体化降压治疗不可或缺的检测手段。本指南对2015年发表的《动态血压监测临床应用专家共识》进行了更新,详细介绍了动态血压计的选择与监测方法、动态血压监测的结果判定与临床应用、动态血压监测的适应证、特殊人群动态血压监测、社区动态血压监测应用以及动态血压监测临床应用展望,旨在指导临床实践中动态血压监测的应用。

Widely-wavelength-tunable brillouin fiber laser with improved optical signal-to-noise ratio based on parity-time symmetric and saturable absorption effect

A widely-wavelength-tunable Brillouin fiber laser(BFL)with improved optical signal-to-noise ratio(OSNR)based on parity-time(PT)symmetric and saturable absorption(SA)effect is present.This novel BFL realizes PT symmetry and SA effect through polarization-maintaining erbium-doped fiber(PM-EDF)Sagnac loop,which is composed of a PM-EDF,a coupler and two polarization controllers(PCs).By using the inherent birefringence characteristic of PM-EDF,two feedback loops in orthogonal polarization state are formed when the Strokes signal in injected.One of these loops provides gain in the clockwise direction with in the Sagnac loop,while the other loop generates loss in the counterclockwise direction.By adjusting the PCs to control the polarization state of the PM-EDF,a single-longitudinal-mode(SLM)BFL can be achieved,as the PT symmetry is broken when the SA participating stimulated Brillouin scattering(SBS)gain and loss are well-matched and the gain surpasses the coupling coefficient.Compared to previous BFLs,the proposed BFL has a more streamlined structure and a wider wavelength tunable range,at the same time,it is not being limited by the bandwidth of the erbium-doped fiber amplifier while still maintaining narrow linewidth SLM output.Additionally,thanks to SA effect of the PM-EDF,the PT symmetric SBS gain contract is enhanced,resulting in a higher optical signal-to-noise(OSNR).The experimental results show that the laser has a wide tunable range of 1526.088 nm to 1565.498 nm,an improved OSNR of 77 dB,and a fine linewidth as small as 140.5 Hz.

Ultrasensitive stretchable patches for joint motion monitoring

Wearable devices have great application potential in the next generation of smart portable electronics,especially in the fields of medical monitoring,soft robotics,artificial intelligence,and human-machine interfaces.Piezoelectric flexible strain sensors are key components of wearable devices.However,existing piezoelectric flexible strain sensors have certain limitations in weak signal monitoring due to their large modulus and low sensitivity.To solve this problem,the concept of Kirigami(paper-cutting)was introduced in this study to design the sensor structure.By comparing the Kirigami structures of different basic structures,the serpentine structure was determined as the basic configuration of the sensor.The serpentine structure not only provides excellent tensile properties,but also significantly improves the sensitivity of the sensor,which performs well in monitoring weak signals.On this basis,the adhesion properties of the flexible sensor were analyzed and tested,and the optimal ratio of the substrate was selected for preparation.In addition,a low-cost and rapid prototyping process for stretchable patches was established in this study.Using this technology,we prepared the sensor device and tested its performance.Finally,we successfully developed a flexible sensor with a sensitivity of 0.128 mV/μɛand verified its feasibility for wrist joint motion monitoring applications.This result opens up new avenues for the recovery care of tenosynovitis patients after surgery.

Control algorithm of YUPENG ship autopilot based on tangent function nonlinear feedback

Autopilot is an important navigation instrument,and it plays an important role in safe navigation In order to further improve the performance of the autopilot,this paper adopts the first-order closed loop gain shaping algorithm(PID)to designautopilot control algo rithm with robustness and uses tangent function nonlinear feedback technology to replace the linear feedback to improve the energy saving effect of autopilot.Taking Dalian Maritime University’s newly-built YUPENG ship as anexample,the simulation research is carried out.The results show that the control effect is still satisfactory when the model parameterschange by25%,which suggests that the designed autopilot algorithm has good robustness.Compared with linearfeedback,nonlinear feedback can save7.9%of energy.The algo rithm proposed in this paper is simple and has obvious physicalmeaning.At the same time,the control algorithm is also helpful for the localization of controller design

Trajectory tracking and obstacle avoidance method for robots based on fast terminal sliding mode

For accurate trajectory tracking and obstacle avoidance in finite time of a nonholonomic mobile robot,a trajectory tracking controller based on global fast terminal sliding mode method is proposed,which has the advantages of chattering-free and adjustable convergence time.First of all,the kinematics model of the robot is established in mobile carrier coordinates.Secondly,the global structure including terminal attractor and exponential convergence of the fast terminal sliding mode trajectory tracking controller is proved by Lyapunov stability theory,ensuring that the trajectory and heading angle tracking error converges to a smaller zero range in finite time.Finally,the artificial potential field obstacle avoidance method is introduced to make the robot not only track the reference trajectory strictly,but also avoid the obstacles.The simulation results show that the proposed method can achieve a stable tracking control in finite time for a given reference trajectory.

Metal-mediated catalysis in the gas phase: A review

This review summarizes a variety of experimentally identified gas‐phase catalytic cycles,all of which are mediated by atomic metal ions,bare metal clusters,metal oxide clusters or metal complexes.Emphasis is placed on the latest advances in the unique catalytic reactivity of cluster‐confined single noble metal atoms.The cycles discussed in this paper cover a wide range of inorganic and organic molecules.The use of start‐of‐the‐art mass spectrometric instrumentation in conjunction with quantum chemistry calculations is also reported,as these techniques have determined the mechanistic details of the elementary steps of such catalytic cycles.The important role of gas‐phase data in guiding the rational design of better‐performing catalysts in related condensed phase reactions is also examined.In particular,this review focuses on the following three topics:(1)the catalytic oxidation of carbon monoxide,(2)the catalytic functionalization of methane,and(3)catalytic decarboxylation.

Optical polarization imaging for underwater target detection with non-scatter background

For conventional optical polarization imaging of underwater target,the polarization degree of backscatter should be pre-measured by averaging the pixel intensities in the no target region of the polarization images,and the polarization property of the target is assumed to be completely depolarized.When the scattering background is unseen in the field of view or the target is polarized,conventional method is helpless in detecting the target.An improvement is to use lots of co-polarization and cross polarization detection components.We propose a polarization subtraction method to estimate depolarization property of the scattering noise and target signal.And experiment in a quartz cuvette container is performed to demonstrate the effectiveness of the proposed method.The results show that the proposed method can work without scattering background reference,and further recover the target along with smooth surface for polarization preserving response.This study promotes the development of optical polarization imaging systems in underwater environments.

An active temperature compensated fiber Bragg grating vibration sensor for high-temperature application

An active temperature compensated fiber Bragg grating(FBG)vibration sensor with a constant section cantilever beam is proposed for the simultaneous measurement of temperature and vibration,and the sensor is verified by a temperature compensation feedback system.The high-temperature vibration sensor is composed of a quartz cantilever beam and a femtosecond Bragg grating.The feedback control demodulation system of active temperature compensation can adjust the laser wavelength to stabilize the grating offset point and realize simultaneous measurement of temperature and vibration.On this basis,the performance of the sensor is tested and analyzed within the range of 20-400℃by setting up a high-temperature vibration test system.The experimental results show that the sensitivity of the sensor is about 132.33 mV/g,and the nonlinearity is about 3.33%.The sensitivity between the laser wavelength and temperature is about 0.01307 nm/℃.In addition,the active temperature compensated fiber Bragg grating vibration sensor has the advantages of a simple structure,stable performance,easy demodulation and high sensitivity.Moreover,the sensor can achieve high temperature vibration signal monitoring and has good practical application value.

Analysis and compensation of low frequency characteristics of sensors for vibration testing

In view of the influence and harm of low frequency vibration environment on the structure of spaceflight products,a low frequency dynamic study method for piezoelectric sensor based on the dynamic system of sinusoidal pressure is proposed.This method uses a sinusoidal pressure dynamic system with two-way dual channel import and export synchronization technology to study the low frequency characteristics of a piezoelectric sensor of PCB company,and its lower cut-off frequency is 0.26 Hz.It is also studied that when the frequency of the measured vibration or shock signal is 1-200 kHz,the error range of signal positive pressure action time is 4.87%-0.03%.The dynamic compensation for the low frequency of the vibration sensor is carried out,and the compensation effect is good.

An improved crossbar array of memristor

This paper conducts an analysis of HP model of a memristor and memory cells of a differential type memristor,formsa classic array of the memristor using the HP model,and does the stimulation of its storage capacity.Based on differential typememristor cells,this paper proposes an improved crossbar array of the memristor,which can be applied in image storage.Bymeans of theoretical analysis and stimulation,this improved crossbar array of memristor has been proved to have bettergrayscale image storage capacity,and its peak signal-to-noise ratio(PSNR)has been improved by about30%.

Acoustic multipolar local effects of metamaterial with annular columnar structures

Research of the acoustic local effect of metamaterial is widely used in the fields of environmental science,military industry and biomedicine.In this paper,the metamaterial is designed by annular columnar structures.The acoustic local effect in slender columnar structure with two layers of rings in air is investigated.Results prove that when the plane acoustic wave is incident into the model,complex interference and diffraction occur.And at different frequencies,multipolar acoustic local effect existes and cycle distribution phenomenon is observed.It is noteworthy that this phenomenon has very weak relatedness with the materials and acoustic parameters of the model.The research of this metamaterial design in this paper has definite reference significance in the acoustic communication and amplification of the acoustic signal detection.

Acoustic focusing effect of composite metamaterial column in air

The acoustic focusing effect of metamaterial has a wide range of applications in medicine,acoustic imaging,signal detection,etc.This paper presents an acoustic metamaterial applied to the acoustic focusing effect.The formation of acousticmetamaterial is designed into a cylindrical structure with three layers of ludox,cork and fluid rubber,which can produce a focusingphenomenon when acoustic waves propagate in air.For these strange phenomena,a scientific description is given theorietically.It can also be concluded that when the frequency of the incident acoustic wave increases?the number of peripheral bandsoutside the focusing poles will increase periodically.Besides,there are numerous groups of multipolar focusing phenomena inhigh frequency.The design of this acoustic metamaterial is successful through theorietical and experimental verification,therefore,it can be applied to acoustic communication and test.

Smart projectile acceleration testing in harsh launch environment

In order to solve the problem of parametric test of smart projectile launch,the launch environment of smart projectile was analyzed.a reasonable and feasible storage testing method was proposed,and a multi-channel test system suitable for the environment was designed.The system was successfully applied to a certain range test,and dynamic parameters such as triaxial acceleration of smart projectile launch environment were acquired.The test results play an important role in the improvements of smart projectile design process.

Minimum variance adaptive beamforming combined with coherence factor weighting applied to ultrafast active cavitation imaging

The ultrafast active cavitation imaging(UACI)based on plane wave transmission and delay-and-sum(DAS)beamforming has been developed to monitor cavitation events with a high frame rate.However,DAS beamforming leads to images with limited resolution and contrast.In this paper,minimum variance(M V)adaptive beamforming and coherence factor(CF)weighting are combined to achieve an MVCF-based UACI,which can improve the cavitation imaging quality.The detailed algorithm evaluation has been investigated from both simulation and experimental data The simulation data include10point targets and a cyst,while the experimental data are obtained by detecting the dissipation of cavitation bubbles in water excited by a single element transducer with frequency of1.2MHz.The advantages of the proposed methodology as well as the comparison with conventional B-mode,DAS?M V,DAS-CF and MV on the basis of compressive sensing(CS)(called MVCS)beamformers are discussed.The results show that MVCF beamformer has a significant improvement in terms of both resolutions and signal-to-noise ratio(SN R).The MVCF-based UACI has a SNR at21.82dB higher,lateral and axial resolution at2.69times and1.93times?respectively,which were compared with those of B-mode active cavitation mapping.The MVCF-based UACI can be used to image the residual cavitation bubbles with a higher SNR and better spatial resolution

Activation of Dinitrogen by Gas-Phase Species

Reactions of gas-phase species with small molecules are being actively studied to understand the elementary steps and mechanistic details of related condensed-phase processes.Activation of the very inert N≡N triple bond of dinitrogen molecule by isolated gas-phase species has attracted considerable interest in the past few decades.Apart from molecular adsorption and dissociative adsorption,interesting processes such as C-N coupling and degenerate ligand exchange were discovered.The present review focuses on the recent progress on adsorption,activation,and functionalization of N2 by gas-phase species(particularly metal cluster ions)using mass spectrometry,infrared photo-dissociation spectroscopy,anion photoelectron spectroscopy,and quantum chemical calculations including density functional theory and high-level ab initio calculations.Recent advances including characterization of adsorption products,dependence of clusters’reactivity on their sizes and structures,and mechanisms of N≡N weakening and splitting have been emphasized and prospects have been discussed.

CO Oxidation by Neutral Gold-Vanadium Oxide Clusters

Oxidation of CO by gas-phase atomic clusters is being actively studied to understand the molecular-level mechanisms of heterogeneous CO oxidation over related catalytic surfaces. However, it is experimentally challenging to study CO oxidation by neutral heteronuclear metal oxide clusters because of the difficulty of cluster ionization and detection without fragmentation. Herein, the neutral AuVO2-4 clusters were experimentally generated and their reactions with CO and O2 were studied. The experimental results showed that CO adsorption is the dominant channel on the interactions of AuVO4 and AuVO3 with CO, and AuVO2 can pick up an O2 molecule to generate AuVO4. Theoretical studies indicated that the oxidation of the trapped CO in AuVO3,4CO into CO2 is exothermic while the reaction barriers have to be overcome at the elevated temperatures. A catalytic cycle for CO oxidation by AuVO2-4 is proposed.

Exploration of the active phase of the hydrotalcite-derived cobalt catalyst for HCHO oxidation

A series of Co-based oxide catalysts were prepared by calcining hydrotalcite precursors in different atmospheres and studied for HCHO catalytic oxidation. The N2-calcined catalyst exhibits enhanced HCHO oxidation and superior stability. On the basis of H2-TPR, X-ray photoelectron spectroscopy, and Raman characterizations, this can be ascribed to better redox ability, octahedrally coordinated Co2+ ions derived from the CoO phase, and other surface oxygen species, such as O2– or O–. The extra octahedrally coordinated Co2+ ions may reside in a more open framework site than the inactive tetrahedrally coordinated Co2+ ions. This species of Co2+ can easily make contact with oxygen and oxidize. The surface oxygen species, along with the octahedrally coordinated Co2+ ions, and a part of the Co3+ species constitute the Co2+-oxygen species-Co3+ sites, which enhance the catalytic activities. According to DRIFTS, Co2+-oxygen species-Co3+ makes oxidation of HCHO and conversion of DOM to formate easier.

3D SERS substrate based on nanocone forests for miRNA detections

Surface-enhanced Raman scattering(SERS)is a powerful technology for obtaining vibrational information from molecules that present in different chemical or biological environments.This paper presents a 3D SERS substrate based on nanocone forests.The substrates are prepared by using plasma treatment technique,which is a simple,fast and high-throughput approach.The SERS substrate based on nanocone forests exhibits high sensitivity.In the experiment,miRNA with a concentration as low as 10-10 M can be achieved.Meanwhile,the proposed SERS substrate shows a high uniformity over a large area.These experimental results demonstrate great potential of the 3D SERS substrate in wide applications.

Recent design and applications of flexible electrodes based on Ag nanowires and nanoparticles:a review

The recent rapid growth in electronics has reached the point where there is a need for solid-state devices with excellent physical flexibility, which will be a significant advantage in modern electronic devices. In particular, metal nanowires and nano-particles are chosen for electrodes because of their low resistance and high mechanical stability. Among the various alternatives, Ag nanomaterials have recently garnered increasing attention due to the high intrinsic conductivity, a transparency with a low sheet resistance and relatively low cost. We herein summarize recent developments toward flexible electronics on the basis of Ag nanomaterials , which show promising performance and outperform the commonly used. The typical fabrication techniques along with the promising applications for flexible devices, are thoroughly discussed.