Theoretical Analysis of Nano Displacement of Nanometer Precision Actuator and Its Application

The kind of micro-/nano-meter precision actuator in cludes a piezoelectric one, an electric deformation one, a magnetic deformation one, a mechanical one, and a mechanical and electrical one. This paper puts forw ard a mechanical and electrical step actuator of nanometer precision, which cons ists of a step motor of large fine-dividing number of step angle, shaft couplin gs, a decelerator of large decelerating ratio, a screw mechanism and a pole of U shape, and has the minimum step displacement of 10 nm, the step displac ement precision of 1 nm, the step frequency of 4 kHz, the maximum loadability of 20 kg. In order to achieve the nano displacement of nano precision by this actu ator, the theoretical analysis of stress and strain must be made on the transmit ting course of nano displacement of the actuator, and their numerical simulation is done by computer. The paper establishes the constitutive equation of 3-D stress and the strain co ordinate equation of the composing system of the nanometer precision actuator. A s a result, the theoretical relation among stress and strain and displacement is set up. The torque of the step motor produces a thrust to transmit the displace ment of the above system of the parts and assemblies to output the needed nano d isplacement. In the case of concrete analysis and calculating, the comparing met hod of film-roof is applied to analyze and calculate the motor axis, decelerato r axes, the screw pole and the nut. The analysis method of plane stress and stra in is used to analyze and calculate the shaft couplings and gears. The analysis method of beam stress and strain is used to do the pole of U shape. These calcul ation is belong to the physical non-linear problem. Under the condition of smal l deformation, the analysis way of the finite element can be combined with the a bove analyses and calculations. The elementary analysis results show that the na nometer precision actuator can be applied in STM nanofabrication.

Cryo-EM Data Statistics and Theoretical Analysis of KaiC Hexamer

Cryo-electron microscopy(cryo-EM) provides a powerful tool to resolve the structure of biological macromolecules in natural state. One advantage of cryo-EM technology is that different conformation states of a protein complex structure can be simultaneously built, and the distribution of different states can be measured. This provides a tool to push cryo-EM technology beyond just to resolve protein structures, but to obtain the thermodynamic properties of protein machines. Here, we used a deep manifold learning framework to get the conformational landscape of Kai C proteins, and further obtained the thermodynamic properties of this central oscillator component in the circadian clock by means of statistical physics.

High-performance triboelectric nanogenerator based on theoretical analysis and ferroelectric nanocomposites and its high-voltage applications

With the growing economy and technology,disease prevention and individual health are becoming more and more important.It is highly urgent to develop a non-toxic,self-powered,and safe high-voltage power source to prevent diseases spread by mosquitoes,especially in isolated or remote areas.Herein,we reported a high-performance rotary triboelectric nanogenerator(R-TENG)based on customized theoretical simulations and a ferroelectric nanocomposite intermediate layer.The customized theoretical simulations based on gradient electrode gaps were established to optimize gap angles and segment numbers of the electrodes,which could prevent air breakdown and enhance the R-TENG output energy by at least 1.5 times.Meanwhile,the electrical output performance of the TENG was further enhanced with a highly oriented BaTiO3(BTO)nanoparticles intermediate layer by about 2.5 times.The open-circuit voltage of R-TENG reached more than 6 kV and could continuously light 3420 light-emitting devices(LEDs)or 4 serially connected 36 W household fluorescent lamps.Therefore,a self-powered high-voltage disease prevention system is developed based on the high-performance R-TENG to reduce the risk of disease transmission.This work provides a prospective strategy for the further development of TENGs and expands practical applications of self-powered and high-voltage systems.

Theoretical analysis for sound wave scattering by parallel cylindrical tubes in boilers

Although the sonic soot cleaning techniques have been applied in boilers in power plants, petrochemical works and general industries world wide, most of the correlated basic problems have not been well solved yet. By using Helmholtz integral equation, sound wave scattered by heat-exchanger tubes is numerically calculated. Sound field distribution characteristics on the tube surfaces and around the tube group is obtained. The results can be applied to the development of sonic soot cleaning techniques in boilers.

Multiple Impact Phenomenon in Impact Hammer Testing:Theoretical Analysis and Numerical Simulation

As conducting an impact hammer testing during experimental modal analysis,the multiple impact phenomenon must be avoided.It is generally recognized that the multiple impact phenomenon is induced by the tester’s improper operation and can be avoided through more careful operation.This study theoretically and numerically investigates the whole process of the dynamical interaction between the hammer tip and the impacted structure and discovers the intrinsically physical mechanism of the multiple impact phenomenon.The determination of the interacting process comes down to solve two sets of governing differential equations alternately,and the effectiveness of the theoretical analysis is validated by numerical simulations.Four dimensionless parameters governing the interacting process are recognized in the theoretical framework.The critical stiffness ratio for a given impacted location and the critical impacted location for a given stiffness ratio are analytically determined.These results can guide impact hammer testing to avoid the occurrence of multiple impact by suggesting the hammer tip and impacted locations.

Theoretical analysis and experimental research on port/starboard discrimination in towed line array

The theoretical analysis and experimental research on Port/Starboard (P/S) discrimination in towed line array are proposed. Two methods resolving the P/S ambiguity with hydrophone triplets are introduced. By processing experimental data, the theoretical analysis is verified. The processing algorithm is extended to broadband signal. The research results show that the method based on optimum beamforming with triplets can be used to remove the port/starboard ambiguity. Also because of the simplicity of the method, it is expected to be implemented in practical towed line array sonar.

Comprehensive Molten Salt Storage Shell and Supporting Structure Design and Analysis-Part I:A Conductive and Convective Theoretical Heat Transfer Analysis for Molten Salt Cylindrical Shells at 565℃ and 700℃

In this paper a full theoretical thermal analysis of a large molten salt container,80-foot in diameter and 46-foot high,including a four-foot elliptic shell roof,is presented for two temperatures,the standard 565℃ and a futuristic 700℃,which substantially improves the efficiency of the molten salt containers through the use of a highly stable chloride salt called SS700(SaltStream 700).The theoretical analysis includes conductive and convective heat transfer analysis in the steel container,elliptic roof shell,the fiberglass insulation,and firebrick insulation,and includes thermal insulation designs to safeguard against energy losses at high temperatures.The underlying soil and the high temperature concrete foundation were analyzed theoretically using conductive heat transfer,however the area surrounding the soil surface around the bottom of the molten salt storage tank had convective heat transfer analysis included.The final designs presented in this paper seek to limit heat losses to a maximum of 250 W/m^(2) while being able to operate at a minimum external ambient temperature of-10℃,which determines the thicknesses of the fiberglass and firebrick insulation.

THEORETICAL ANALYSIS OF ATMOSPHERIC WAVES IN EQUATORIAL ZONE

In the equatorial zone the dynamic equations of the atmospheric motion are written inthe β-plane.These equations are linearized according to the mean atmospheric conditions.Numerical method is used to obtain a characteristic wave solution. Results obtained showthat the easterly wind shear changes the phase speed of low frequency waves more strikinglythan that of high frequency waves. The structure of the characteristic disturbances is sim-ilar to that in middle latitudes only with some exceptions in the relationship of geopo-tential field with vorticity field.

A theoretical analysis on second harmonic generation for transverse and longitudinal slice collagen fiber

Microscopic imaging based on second-harmonic generation has been proving to be a powerful tool for biomedical studies, especially in that tissues with

Theoretical analysis of acoustic suspended sediment observation

A theoretical analysis of designing an acoustic backscatter system for observations of suspended sediments has been made through a derived sonar equation. Some formulae and data for reference in determining several main technical parameters of the system, such as optimum frequency, sound transmission power, aperture of transducer etc., airs provided. And some key problems on the acoustic observation of suspended sediments, such as data processing of a time--Varying stochastic process, compensation of sound propagation loss in complicated conditions and in-situ calibration of sediment concentration, are discussed in detail. The results of the analysis could be helpful to the development and application of a specific acoustic backscatter instrument (e.g. the acoustic sediment concentration profiler, the acoustic Doppler current profiler etc.).

Theoretical analyses on the one-dimensional charged particle transport in a decaying plasma under an electrostatic field

The spatiotemporal evolutions of a one-dimensional collisionless decaying plasma bounded by two electrodes with an externally applied electrostatic field are studied by theoretical analyses and particle-in-cell(PIC)simulations with the ion extraction process in a laser-induced plasma as the major research background.Based on the theoretical analyses,the transport process of the charged particles including electrons and ions can be divided into three stages:electron oscillation and ion matrix sheath extraction stage,sheath expansion and ion rarefaction wave propagation stage and the plasma collapse stage,and the corresponding criterion for each stage is also presented.Consequently,a complete analytical model is established for describing the ion extraction flux at each stage during the decaying of the laser-induced plasmas under an electrostatic field,which is also validated by the PIC modeling results.Based on this analytical model,influences of the key physical parameters,including the initial electron temperature and number density,plasma width and the externally applied electric voltage,on the ratio of the extracted ions are predicted.The calculated results show that a higher applied electric potential,smaller initial plasma number density and plasma width lead to a higher ratio of the extracted ions during the first stage;while in this stage,the initial electron temperature shows little effect on it.Meanwhile,more ions will be extracted before the plasma collapse once a higher electric potential is applied.The theoretical model presented in this paper is helpful not only for a deep understanding to the charged particle transport mechanisms for a bounded decaying plasma under an applied electrostatic field,but also for an optimization of the ion extraction process in practical applications.

Settlement Mode Analysis for An Immersed Tube Tunnel Considering A Nonuniform Foundation Under Tidal Load

Immersed tube tunnels are usually placed on soft soil layers in cross-sea tunnelling engineering.Owing to the influence of stratum conditions and slope design,the longitudinal distribution of substratum layers is generally uneven.Thus,the inhomogeneous deformation of the element-joint becomes the key factor in the failure of the immersed tube tun-nel.Therefore,a corresponding calculation method for joint deformation is needed to explore the deformation law of immersed tube tunnels.By constructing a three-section immersed tube tunnel analysis model(TTM),the relationship between the two types of deformation of the immersed tube tunnel structure in a longitudinal nonuniform soft soil foundation is described,and the deformation characteristics of the immersed structure under different boundaries are discussed.Based on the mechanical behaviour of the joint and foundation,according to the Timoshenko beam on the Vlasov two-parameter foundation(VTM),considering the tidal cyclic load during the operation and maintenance period,an example analysis is given.Moreover,the deformation characteristics and development trend of the immersed tube tunnel under the influence of different soil layers are discussed.The obtained results have a certain guiding significance for the deformation calculation of immersed tube tunnels.

CRYPTANALYSIS OF AN IMAGE ENCRYPTION SCHEME WITH A PSEUDORANDOM PERMUTATION AND ITS IMPROVED VERSION

Under Kerckhoff principle,this paper discusses the security property of an image encryp-tion scheme with a pseudorandom permutation.Some findings on the security problems of the algo-rithm are reported in the following:(1) If each row or column of the plain-image matrix is the same,the receiver cannot decrypt correctly.(2) Each plain-text word is correlated with single cipher-text word,but independent of other cipher-text word,which cannot meet the principles of algorithm design-diffusion and confusion.(3) If the cycle numbers are relatively small,statistics attack can be used to reveal some visual information of any other plain-images encrypted with the same secret key.Con-sidering the above problems,we propose an improved algorithm and then analyze its performance.Theoretical analysis and simulation results show that the improved algorithm can obtain better cryptographic properties,such as statistical characteristics,difference characteristics,and so on.

Mechanism of CO_(2)reduction in carbonylation reaction promoted by ionic liquid additives:A computational and experimental study

The Ru-catalyzed carbonylation of alkenes with CO_(2)as a C1 surrogate and imidazole chlorides as the promotor is investigated by a combination of computational and experimental study.The conversion rate of CO_(2)to CO is positively correlated with the efficiency of both hydroesterification and hydroformylation,which is found facilitated in the presence of chloride additives with a decreasing order of BmimCl~B3MimCl>BmmimCl~LiCl.Taking the hydroesterification with MeOH as a representative example,BmimCl bearing C-H functionality at the C^(2)site of the cation assists the reduction of CO_(2)to CO as a hydrogen donor medium,with the anion and cation acting in a synergistic fashion.Subsequent insertion of CO_(2)into the formed Ru-H bond with the assistance of chloride anion produces the Ru-COOH species,which ultimately accelerates the activation of CO_(2).

Progress of Brain Network Studies on Anesthesia and Consciousness: Framework and Clinical Applications

Although the relationship between anesthesia and consciousness has been investigated for decades, our understanding of the underlying neural mechanisms of anesthesia and consciousness remains rudimentary, which limits the development of systems for anesthesia monitoring and consciousness evaluation. Moreover, the current practices for anesthesia monitoring are mainly based on methods that do not provide adequate information and may present obstacles to the precise application of anesthesia. Most recently, there has been a growing trend to utilize brain network analysis to reveal the mechanisms of anesthesia, with the aim of providing novel insights to promote practical application. This review summarizes recent research on brain network studies of anesthesia, and compares the underlying neural mechanisms of consciousness and anesthesia along with the neural signs and measures of the distinct aspects of neural activity. Using the theory of cortical fragmentation as a starting point, we introduce important methods and research involving connectivity and network analysis. We demonstrate that whole-brain multimodal network data can provide important supplementary clinical information. More importantly, this review posits that brain network methods, if simplified, will likely play an important role in improving the current clinical anesthesia monitoring systems.

A Simplified Method for Estimating the Initial Stiffness of Monopile-Soil Interaction Under Lateral Loads in Offshore Wind Turbine Systems

The interface mechanical behavior of a monopile is an important component of the overall offshore wind turbine structure design.Understanding the soil-structure interaction,particularly the initial soil-structure stiffness,has a significant impact on the study of natural frequency and dynamic response of the monopile.In this paper,a simplified method for estimating the interface mechanical behavior of monopiles under initial lateral loads is proposed.Depending on the principle of minimum potential energy and virtual work theory,the functions of soil reaction components at the interface of monopiles are derived;MATLAB programming has been used to simplify the functions of the initial stiffness by fitting a large number of examples;then the functions are validated against the field test data and FDM results.This method can modify the modulus of the subgrade reaction in the p-y curve method for the monopile-supported offshore wind turbine system.

Sound Absorption Properties of Discarded Feathers/Ethylene Vinyl Acetate Copolymer Thermoplastic Composite Materials

The discarded feathers / ethylene vinyl acetate copolymer( EVA) thermoplastic composite materials was obtained with discarded feathers as reinforced material and EVA powders as matrix material by hot pressing method. Sound absorption properties were studied by changing mass ratio of discarded feathers and EVA,thickness of composite materials,hot pressing pressure and hot pressing temperature. It was found that the sound absorption properties of composite materials were good when the mass ratio of discarded feathers and EVA was 1: 1,thickness of composite materials was 30 mm,hot pressing pressure was 8 MPa,and hot pressing temperature was 80 ℃. Under the optimum conditions,the effect of composite density on sound absorption property was analyzed. In a certain range,the sound absorption property was enhanced with the decrease of the composite density.When the composite density was 0. 1g /cm^3, the maximum absorption coefficient was 0.96. Finally,the capillary theory was used to calculate the maximum sound absorption coefficient of discarded feathers / EVA thermoplastic composite materials. The good agreements of experimental results and calculated results proved the validity of the theoretical models.

Transient Characteristics of a High-Capacity Centrifugal Pump during Rapidly Regulating Discharge Valve

In order to reveal the instantaneous characteristics of a high-capacity centrifugal pump during rapidly regulating discharge valve,theoretical analysis and numerical simulation are employed.The transient characteristics of the pump model under off-design condition were theoretically analyzed based on the generalized basic equation of vane pumps.The study showed that a centrifugal pump with radial straight blades at off-design condition almost had no transient effect,whereas a centrifugal pump with common backward-curved blades had transient effects that were directly related to the regularity of adjusting flowrate.Calculation examples show that transient effects are insignificant.The finite volume method and re-normalization group(RNG)κ-ε turbulence model were adopted to accomplish a 3D numerical calculation of a mediumspecific-speed centrifugal pump under the off-design condition.The transient process at the off-design condition is mainly caused by the time-varying intrinsic pulsation from the stator-rotor interference and by the time-varying consequent pulsation from the changes in flow rate.

Milestones of the Modeling of Human Physiology

An overview of about 70-year research efforts in area of mathematical modeling of human physiology is provided.The overview has two goals:(1)to recognize the main advantages and causes of disadvantages or disappointments;(2)to distinguish the most promising approach for creating future models.Until recently,efforts in the modeling of quantitative physiology were concentrated on the solving of three main types of tasks:(1)how to establish the input-output dynamic characteristics of a given isolated organ or isolated anatomical-functional system(AFS);(2)how to create a computer-based simulator of physiological complex systems(PCM)containing many organs and AFSs;and(3)how to create multi-scale models capable of simulating and explaining causalities in organs,AFSs,PCMs,and in the entire organism in terms that will allow using such models for simulating pathological scenarios(the“Physiome”project)too.The critical analysis of the modeling experience and recent physiological concepts convinced us that the platform provided by the paradigm of physiological super-systems(PPS)looks like the most promising platform for further modeling.PPS causally combines activities of specific intracellular mechanisms(self-tunable but of limited capacities)with their extracellular enhancers.The enhancement appears due to the increase of nutrients incomes toward cells affected because of low energy and inadequate chemical composition of cytoplasm.Every enhancer has its activator chemicals released by the affected cells.In fact,PPS,indicating causal relationships between cellscale and upper-scales(in organs,AFSs,PCMs)physiological activities,is the single platform for future models.They must definitely describe when and how the bottom-to-up information flows do appear and how is the organism-scale adaptation activated against destructive trends in cells.