Force CT大螺距Turbo Flash与回顾性心电门控扫描模式在冠状动脉成像图像质量及辐射剂量比较的研究

目的比较第三代双源Force CT大螺距Turbo Flash与回顾性心电门控冠状动脉成像(CTCA)图像质量及辐射剂量。方法收集2023年1-3月接受CTCA检查患者136例,采用大螺距Turbo Flash P组、回顾性心电门控R组,按照心率≤65次/min分P1、R1组,心率>65次/min分P2、R2组,对冠状动脉图像质量进行主观评分,比较剂量长度乘积(DLP)、辐射剂量(ED)。结果P组95.36%、R组95.72%的节段能够满足图像质量要求(P>0.05),P组及R组的年龄、BIM、心率、心率变化值、DLP、ED差异均无统计学意义(P>0.05),P组DLP为44.100(34.8,52.32)mGy·cm,ED为0.617(0.5,0.7)mSv,R组DLP为425.500(365.0,489.1)mGy·cm,ED为5.957(5.0,6.8)mSv,差异均有统计学意义(P<0.05)。图像质量评分右冠状动脉、总体评分P1与P2、P2与R2差异均有统计学意义(P<0.05),余冠脉分段差异无统计学意义(P>0.05),结论Force CT大螺距Turbo Flash扫描模式图像质量佳、成功率高,有效辐射剂量低,可作为低心率患者的优选检查方法,高心率患者所得冠状动脉图像能够满足诊断要求。

Relativized Quantum Physics Generating <i>N</i>-Valued Coulomb Force and Atomic Hydrogen Energy Spectrum

Though not well-known, Einstein endeavored much of his life to general-relativize quantum mechanics, (rather than quantizing gravity). Albeit he did not succeed, his legacy lives on. In this paper, we begin with the general relativistic field equations describing flat spacetime, but stimulated by vacuum energy fluctuations. In our precursor paper, after straightforward general relativistic calculations, the resulting covariant and contravariant energy-momentum tensors were identified as n-valued operators describing graviton excitation. From these two operators, we were able to generate all three boson masses (including the Higgs mass) in precise agreement as reported in the 2010 CODATA (NIST);moreover local, as-well-as large-scale, accelerated spacetimes were shown to naturally occur from this general relativized quantum physics approach (RQP). In this paper, applying the same approach, we produce an n-valued Coulombs Force Law leading to the energy spectrum for atomic hydrogen, without assuming quantized atomic radii, velocity and momentum, as Bohr did.

Rotor Vibratory Load Prediction Based on Generalized Forces

Three rigid-body-motion DOFs are introduced for the motion of the flap, laghinge and pitch bearing. The rotor blade is discretized using a five-nodes, 15 DOFs beam finiteelement. The dynamic coupling effect between the rigid motion of the blade and the nonlinear elasticdeflections is taken into account. Utilizing the constitutive law of the curvilinear coordinatesystem, the typical moderate deflection beam theory is reformulated. In addition, the Leishman andBeddoes unsteady and dynamic stall model is incorporated and the inflow is evaluated with the freewake analysis. The derived nonlinear ordinary differential equations with time - dependentcoefficients of the rotor blade are given in the sense of the generalized forces. The sectionalloads of the blade and the equations of motion are solved simultaneously in the physical space. Theblade vibratory loads predicted by present analysis show generally fair a-greement with the flighttest data of the SA349/2 Gazelle helicopter.

Entropy generation analysis of thermally developing forced convection in fluid-saturated porous medium

Entropy generation for thermally developing forced convection in a porous medium bounded by two isothermal parallel plates is investigated analytically on the basis of the Darcy flow model where the viscous dissipation effects had also been taken into account. A parametric study showed that decreasing the group parameter and the Peclet number increases the entropy generation while for the Brinkman number the converse is true. Heatline visualization technique is applied with an emphasis on the Br 〈 0 case where there is somewhere that heat transfer changes direction at some streamwise location to the wall instead of its original direction, i.e., from the wall.

SOLUTIONS OF A SYSTEM OF FORCED BURGERS EQUATION IN TERMS OF GENERALIZED LAGUERRE POLYNOMIALS

In this article, we obtain explicit solutions of a linear PDE subject to a class of ra-dial square integrable functions with a monotonically increasing weight function｜x｜n-1eβ｜x｜2/2,β ≥ 0, x ∈ Rn. This linear PDE is obtained from a system of forced Burgers equation via the Cole-Hopf transformation. For any spatial dimension n＆gt;1, the solution is expressed in terms of a family of weighted generalized Laguerre polynomials. We also discuss the large time behaviour of the solution of the system of forced Burgers equation.

Stochastic response analysis of noisy system with non-negative real-power restoring force by generalized cell mapping method

The stochastic response of a noisy system with non-negative restoring force is investigated. The generalized cell mapping （GCM） method compute the transient and stationary probability density functions （PDFs） real-power is used to Combined with the global properties of the noise-free system, the evolutionary process of the tran- sient PDFs is revealed. The results show that stochastic P-bifurcation occurs when the system parameter varies in the response analysis and the stationary PDF evolves from bimodal to unimodal along the unstable manifold during the bifurcation.

CONVERGENCE RATES FOR THE COMPRESSIBLE NAVIER-STOKES EQUATIONS WITH GENERAL FORCES

For the viscous and heat-conductive fluids governed by the compressible Navier- Stokes equations with external force of general form in R^3, there exist nontrivial stationary solutions provided the external forces are small in suitable norms, which was studied in article [15], and there we also proved the global in time stability of the stationary solutions with respect to initial data in H^3-framework. In this article, the authors investigate the rates of convergence of nonstationary solutions to the corresponding stationary solutions when the initial data are small in H^3 and bounded in L6/5.

Generalized Orbitals under the Influence of 2D Central and Noncentral Forces

In polar coordinate system, we consider fifteen classes of forces resulting in unlimited undiscovered orbitals. The classic conic orbits are one of the special subclasses of the fifteen classes. Among the rest of the forces, we show a few instances displaying typical fresh orbitals. Aside from the common theoretical foundation, the specifics of the orbitals are given by the solution of corresponding equations of motion. These are coupled nonlinear differential equations. Solving these equations numerically, utilizing a Computer Algebra System such as Mathematica is conducive to the orbits. Simulation of the orbitals provides a visual understanding about the motion under the influence of the generalized noncentral forces.

Seismic Theory of Tides; Theory of Forced Seismic Waves

Proceeding from the statement about presence of the normal resilient medium in the cosmic space, the author concludes seismic nature of tides and a number of other aspects of this phenomenon. The analysis of contradiction of the theory of tsunami to empiric facts led the author to conclude that the tsunami are forced and not free waves, and that the key moment in their distribution is the seismic compression of water.

Analysis of flow instabilities in forced-convection steam generator

Because of the practical importance of two-phase instabilities, substantial efforts have been made to date to understand the physical phenomena governing such instabilities and to develop computational tools to model the dynamics. The purpose of this study is to present a numerical model for the analysis of flow-induced instabilities in forced-convection steam generator. The model is based on the assumption of homogeneous two-phase flow and ther- modynamic equilibrium of the phases. The thermal capacity of the heater wall has been included in the analysis. The model is used to analyze the flow instabilities in the steam generator and to study the effects of system pressure, mass flux, inlet temperature and inlet/outlet restriction, gap size, the ratio of do / di, and the ratio of qi / qo on the system be- havior.

Optical pulse shaper with integrated slab waveguide for arbitrary waveform generation using optical gradient force

Integrated optical pulse shaper opens up possibilities for realizing the ultra high-speed and ultra wide-band linear signal processing with compact size and low power consumption. We propose a silicon monolithic integrated optical pulse shaper using optical gradient force, which is based on the eight-path finite impulse response. A cantilever structure is fabricated in one arm of the Mach–Zehnder interferometer（MZI） to act as an amplitude modulator. The phase shift feature of waveguide is analyzed with the optical pump power, and five typical waveforms are demonstrated with the manipulation of optical force. Unlike other pulse shaper schemes based on thermo–optic effect or electro–optic effect, our scheme is based on a new degree of freedom manipulation, i.e., optical force, so no microelectrodes are required on the silicon chip,which can reduce the complexity of fabrication. Besides, the chip structure is suitable for commercial silicon on an insulator（SOI） wafer, which has a top silicon layer of about 220 nm in thickness.

Theoretical Calculation of Lift Force for General Electric Asymmetric Capacitor Loaded by High Voltage

Lift force of an asymmetric capacitor in arbitrary shape still cannot be precisely calculated. For an irregular surface of a general asymmetric capacitor of which electric charge is nonuniformly distributed, we dedicate effort to filling the gap of lift force calculation problem. Through theoretical derivation, a general formula result is achieved. By applying theoretical formula combining with experimental method based on similarity principle of dimensional analysis, we can almost figure out all types of lift force of asymmetric capacitor. It is really an exciting method which can universally solve the hard thrust force calculation problem completely.

NEW SCALAR-TYPE EQUILIBRIUM EQUATIONS OF THE GENERAL SPACE FORCE SYSTEM

Using the principle of analytical geometry, several properties of the space straight lille are proved. Based on these properties, the equilibrium of general space force system is considered and its four new scalar-type equilibrium equations are derived which are equivalent to the vector-type necessary and sufficient conditions far equilibrium.

VR-Forces计算机兵力生成程序分析与设计

计算机生成兵力程序的开发环境一般是基于外军环境与武器模型进行构建,为了适应具体的需求,用户必须进行仿真功能的自定义和扩展。以VR-Forces为计算机生成兵力开发环境,对VR-Forces程序结构、类层次结构、类工厂机制和API接口进行分析,利用VisualC++开发环境和VR-Forces提供的应用编程接口(Application Programming Interface),对VR-Forces提供的源程序重新进行编程与编译,建立一个自定义的、实现了功能扩展的计算机兵力生成程序,试验数据表明,新的仿真系统功能得到扩展,运行正确,具有较好的适用性。

基于VR-Forces的水面舰艇防空作战仿真

作战模拟是水面舰艇对空防御研究的有效手段之一,VR-Forces为此提供了有力的支持。首先建立了基于VR-Forces的舰空对抗仿真系统,分析了基于VR-Forces组件式作战兵力实体结构特点,提出了基于功能组件的实体结构元模型;在电子对抗模型的基础上,以雷达告警仿真为例建立了基于VR-Forces的水面舰艇对空防御仿真组件开发过程,对组件及组件间的数据流程进行详细说明。所提出的开发方法已经成功运用于多型作战模拟训练系统中,实现了电磁环境下的舰空对抗训练。

Tooth Position and Deformation of Flexspline Assembled with Cam in Harmonic Drive Based on Force Analysis

Deformation of the flexspline is the basis of analyzing tooth trajectory and designing tooth profile.Considering the tooth influence on the position of equivalent neutral layer,a piecewise method for calculating the deformation of flexspline assembled with a cam wave generator is presented in this paper.Firstly,a mechanic model of a ring of uniform thickness in contact with a rigid cam is established.The displacements of the ring inside and outside an unknown wrapping angle are determined by the geometric constraints of the cam profile and the equilibrium rela-tionship,respectively.Meanwhile,the wrapping angle is solved according to the boundary conditions.The assembly forces are derived to investigate the circumferential elongation and strain.Then,considering the tooth effects on the neutral layer of flexspline,the tooth is positioned on the equivalent neutral layer,which is the non-elongation layer within one gear pitch but offset from the geometric mid-layer.The equivalent neutral layer is positioned by the empirical formula of the offset ratio,which is summarized by the orthogonal simulation on finite element models of racks.Finally,finite element models of a ring-shaped and a cup-shaped flexspline assembled with elliptical cam are established to verify the effectiveness and accuracy of the piecewise method.The results show that,compared with the geometric method,the tooth positioning deviation calculated by the piecewise method can be reduced by about 70%with a more accurate deformation description from the geometric condition and mechanic condition inside and outside the wrapping angle.

Analysis of Possible Nonlocal Forces in Superconducting Materials

In this work, we show that anomalous forces in rotating superconductor rings seem to be nonlocal in its nature, according to same theoretical framework in our previous analysis concerning to superconducting disks and toroids. Here we discuss an experiment involving rotating and angularly accelerated superconducting rings and show that the concept of generalized quantum entanglement can explain the anomaly accordingly. In fact, the hypothesis of momentum variation exchanged between Cooper pairs and outer particles regarding a hypothesis of preexisting state of generalized quantum entanglement which is also valid in this system because classical macroscopic quantities are performed in the calculation and indicate good agreement between experimental and theoretical results. We also analyze the possible reason for the discrepance between positive and null results in case of some high voltage discharge experiments involving superconducting discs in terms of nonlocal force induction aiming to reinforce that the anomalous effect can really exist in all of those superconducting systems. The experiments indicate that the anomalous forces are still weak, but our study can provide some possible physical conditions in order to increase the magnitude of the forces and provide future viable technological applications from that phenomenon.

Induction of Forces at Distance Performed by Piezoelectric Materials

We describe the phenomenon of generation of an external field of forces from piezoelectric materials subjected to the application of electric fields or mechanical stress. We show that piezoelectric materials are capable of producing nonlocal forces of induction in external objects and we conclude that the nature of the forces generated is not originated from traditional interactions. Further we specifically assert that the generation of forces by the piezoelectric materials is ruled by the hypothesis of preexisting condition of generalized quantum entanglement between the molecular structure of the material bulk and the surrounding environment. In addition, the widely spread coupling of the molecules with the environment can be manifested from the so-called direct effect or the converse effect in piezoelectric materials and this coupling is not intermediated by acoustic waves or electromagnetic fields. We show that the novel effect has a theoretical explanation consistent with the generalized quantum entanglement framework and the direction of the induced forces depends on either the direction of the mechanical force or the electric field applied in these materials.

A Study on Sulfate Optical Properties and Direct Radiative Forcing Using LASG-IAP General Circulation Model

The direct radiative forcing （DRF） of sulfate aerosols depends highly on the atmospheric sulfate loading and the meteorology, both of which undergo strong regional and seasonal variations. Because the optical properties of sulfate aerosols are also sensitive to atmospheric relative humidity, in this study we first examine the scheme for optical properties that considers hydroscopic growth. Next, we investigate the seasonal and regional distributions of sulfate DRF using the sulfate loading simulated from NCAR CAM-Chem together with the meteorology modeled from a spectral atmospheric general circulation model （AGCM） developed by LASG-IAP. The global annual-mean sulfate loading of 3.44 mg m-2 is calculated to yield the DRF of -1.03 and -0.57 W m-2 for clear-sky and all-sky conditions, respectively. However, much larger values occur on regional bases. For example, the maximum all-sky sulfate DRF over Europe, East Asia, and North America can be up to -4.0 W m-2. The strongest all-sky sulfate DRF occurs in the Northern Hemispheric July, with a hemispheric average of -1.26 W m-2. The study results also indicate that the regional DRF are strongly affected by cloud and relative humidity, which vary considerably among the regions during different seasons. This certainly raises the issue that the biases in model-sinmlated regional meteorology can introduce biases into the sulfate DRF. Hence, the model processes associated with atmospheric humidity and cloud physics should be modified in great depth to improve the simulations of the LASG-IAP AGCM and to reduce the uncertainty of sulfate direct effects on global and regional climate in these simulations.

Dynamic response in two-dimensional transversely isotropic thick plate with spatially varying heat sources and body forces

This paper deals with a two-dimensional （2D） problem for a transverselyisotropic thick plate having heat sources and body forces. The upper surface of the plate is stress free with the prescribed surface temperature, while the lower surface of the plate rests on a rigid foundation and is thermally insulated. The study is carried out in the context of the generalized thermoelasticity proposed by Green and Naghdi. The governing equations for displacement and temperature fields are obtained in the Laplace-Fourier transform domain by applying the Laplace and Fourier transforms. The inversion of the double transform is done numerically. Numerical inversion of the Laplace transform is done based on the Fourier series expansion. Numerical computations are carried out for magnesium （Mg）, and the results are presented graphically. The results for an isotropic material （Cu） are obtained numerically and presented graphically to be compared with those of a transversely isotropic material （Mg）. The effect of the body forces is also studied.