Impact of the equivalent center of mass separating from the sliding surface on the isolation performance of friction pendulum bearings

A new equivalent center of mass model of FPBs (friction pendulum bearings) is introduced, and based on this model, coefficient j of the equivalent center of mass separating from the sliding surface is defined. It is thought in theory that j has a significant impact on the isolation parameter of FPBs, since the equivalent post-yielding stiffness and friction coefficients are not simply determined by sliding radius and sliding friction pairs. The results of numerical simulation analysis using ABAQUS conducted on two groups of FPBs support this viewpoint. For FPBs with the same sliding radius and sliding friction pairs, the FPB modules of structural analysis software such as ETABS could only distinguish the equivalent transformation using j one by one. The seismic response data obtained in a base isolation calculation example of FPBs are very different, which reveals that j’s impact on the isolation effectiveness of FPBs cannot be ignored. The introduction of j will help improve the classical structural theory of FPBs and the weak points of structural analysis software based on this theory, which is important in achieving more accurate analyses in structural design.

The Contribution of the Gravitational Propagation Delay to Orbital and Center of Mass Motions

Recent measurements have shown that gravitational waves and thus the gravitational interaction propagate with the speed of light. The propagation delay of the gravitational interaction in orbiting systems couples the orbital and center of mass motions. This causes the orbits to spiral out and the center of mass to accelerate. It is one of a number of small effects modifying the Kepler orbits. The calculations show that the analytical describable expansion of the semimajor axis started at a time that is less than the age of the systems. This could be caused by a collision of a system component in the past. The effect of this propagation delay on the motion of the Earth Moon and the Brown Dwarf 569Bab binary star system is analyzed. These systems were chosen because a considerable amount of measured astronomical data is available. The calculated results are in excellent agreement with the measured data. In galaxies, too, the energy transfer from the orbit of the star cloud to the center of mass motion causes the galaxies to ac-celerate. If galaxies are considered to be molecules of the universe, then the acceleration of the galaxies will cause the molecular gas to heat and expand. Alternatively, the loss in orbital internal energy of the galaxies should be included in the mass and energy in the calculation of the expanding Universe.

Mass-Spectrometric Method of Measurement of Isotopic Content of Nitrogen in Organic Compounds

Nitrogen-15 isotope-modified compounds are widely used in medicine, pharmacology, agriculture and various fields of science and their nomenclature is gradually increasing. Their widespread use depends on the availability of inexpensive and simple isotope analysis methods. The present article is an attempt to determine the nitrogen-15 isotope content directly in organic compounds without their conversion. The general principle of possibility of determination of the isotopes of nitrogen directly in organic compounds is proposed. Based on the study of mass-spectra of Carbamide Carbonyldiamide, isocyanic acid and nitrobenzene the mass peaks are selected, by which it is possible to determine the atomic fraction of the isotopes of nitrogen. The respective formulas are proposed.

Determination of Carbon and Nitrogen Isotope Fractions in Tartaric Acid, Oxalic Acid, Glucose and Fructose—National Center of High Technologies of Georgia

Tartaric acid, oxalic acid, glucose, and fructose are highly important compounds. A comprehensive study of these substances is fascinating from a scientific perspective. They are key components found in wine, vegetables, and fruits. Understanding the isotopic compositions in organic compounds is crucial for comprehending various biochemical processes and the nature of substances present in different natural products. Tartaric acid, oxalic acid, glucose, and fructose are widely distributed compounds, including in vegetables and fruits. Tartaric acid plays a significant role in determining the quality and taste properties of wine, while oxalic acid is also prevalent but holds great interest for further research, especially in terms of carbon isotopic composition. We can unveil the mechanisms of processes that were previously impossible to study. Glucose and fructose are the most common monosaccharides in the hexose group, and both are found in fruits, with sweeter fruits containing higher amounts of these substances. In addition to fruits, wheat, barley, rye, onions, garlic, lentils, peppers, dried fruits, beans, broccoli, cabbage, tomatoes, and other foods are also rich sources of fructose and glucose. To determine the mass fraction of the carbon-13 isotope in these compounds, it is important to study their changes during natural synthesis. These compounds can be modified with a carbon center. According to the existing isotopic analysis method, these compounds are converted into carbon oxide or dioxide [1]. At this point, the average carbon content in the given compound is determined, but information about isotope-modified centers is lost. Dilution may occur through the transfer of other carbon-containing organic compounds in the sample or by dilution with natural carbon or carbon dioxide during the transfer process. This article discusses the possibility of carbon-13 isotope propagation directly in these compounds, both completely modified and modified with individual carbon centers. The literature provides information on determining carbon-13 substance in organic compounds, both with a general approach and for individual compounds [2] [3].

MASS概念辨析及其四级模式关系研究

通过对MASS相关概念的来源、内涵和隶属关系开展释义和区分,论述MASS译为“智能航行船”的合理性,同时通过分析国际海事组织(IMO)划定的MASS四级模式,明确了四个等级之间不是技术迭代关系,并提出Degree 4完全自主模式的细分层级,对帮助业界明确语义并厘清MASS四级模式之间的关系具有积极作用。

基于IMO分级的MASS岸基操控人员法律地位探析

随着AI技术的发展,人工智能与传统设备的结合已深刻改变了人类的生产生活。MASS(Maritime Autonomous Surface Ships)全称为海上自主水面船舶,其作为人工智能的产物,代表着未来船舶的发展趋势,也推动MASS岸基操控人员这一新兴海事主体的产生。“自动化”并不意味着在MASS的操作过程中完全消除人员因素的干扰,在IMO所定义的MASS发展四阶段中,人在循环中的角色是不断变化的,其职能、责任、法律地位均有所不同,关于岸基操控人员法律地位的认定,具有基础性和高度优先性。L1级别MASS无需岸基操控人员;L2级别MASS岸基操控人员可视作L3级别岸基操控人员的实习或见习期;L3级别岸基操控人员可视为船长或“外部船长”;L4级别MASS系统的优先程度高于人,岸基操控人员仅具有“监督”与作出“降级”决定的职责,不排除其成为新兴海事主体的可能性。

COM技术在制导仿真系统主控软件中的应用

导弹制导仿真试验系统的设备组成具有一定的复杂性,为使导弹制导仿真试验系统中各种不同类型的仿真设备能够协同一致的工作,采用COM技术以及模块化思想对系统的主控软件进行设计开发,使主程序框架以及各功能模块高度独立,实现了半实物仿真试验全过程的高效控制以及状态的实时监测。同时,对不同型号的被试品具有较高的通用性和可扩展性。开发的主控软件在以太网和实时网双网络环境下运行可靠,控制灵活,且数据传输及显示的实时性较高。

Oil Pocket's Bearing Capacity Analysis of Liquid Hydrostatic Worktable in Gantry Moving Milling Center

Durning the design process of hydrostatic rotary worktable,the processing and assembly tolerance,（the offset of worktable and the gap of the oil film’s thickness）is ignored.But it will cause that the real bearing of oil pocket deviates from the initial design value,and then the performance of rotary worktable will be reduced significantly.Up to now,no effort is found toward the research of influence of the processing and assembly tolerance on the performance of the rotary worktable.So the hydrostatic oil film is assumed as the elastomer in this paper,and then the bearing capacity of the oil pocket is studied with and without the mass offset of the worktable by taking an expression between the bearing capacity and the oil film’s thickness of the oil pocket as the deform compatibility equation.The influence of the processing tolerance of the oil sealing belt’s gap on the bearing capacity of the oil pocket is analyzed.In the light of the liquid hydrostatic worktable of Gantry Moving Milling Center using on the scene,the oil pocket’s pressure of the worktable is tested using Rotary Worktable Test System under the circumstance of the mass offset of the worktable and the gap tolerance of the oil sealing belt,and then the equivalent offset of worktable,the average pressure of the oil pocket and the actual thickness of the oil film are analyzed respectively.The test results show that the bearing capacity component of the oil pocket caused by G is consistent,and the component caused by M is relative to the position of the oil pocket.When the oil sealing belt’s gap is larger than the theoretical value,the bearing capacity of the oil pocket is smaller than the others;whereas the bearing capacity of the oil pocket is larger than the others.The maximum and minimum equivalent offsets are 0.256 4 mm and 0.047 5 mm,respectively,and the average oil pocket pressure varies from 0.345 MPa to 0.460 MPa,the maximum and minimum value of the actual oil film thickness are 109.976？m（No.7 oil pocket）and 93.467？m（No.10 oil pocket）,respectively.The research results can be used to detect the offset of the worktable and the actual thickness of the oil film under processing and assembly tolerance,and provides a basis way for detecting the processing and assembly tolerance of rotary worktable signing reasonably of Gantry Moving Milling Center.

Novel Evaluation Method of Vehicle Suspension Performance Based on Concept of Wheel Turn Center

The current research of suspension performance evaluation is mixed in the evaluation of vehicle handling and ride comfort. However, it is lack of a direct and independent evaluation method for suspension performance. In this paper, a novel wheel turn center method is proposed to evaluate the suspension performance. This method is based on the concept and application of wheel turn center （WTC） and sprung mass turn center （SPTC）. The vehicle body and each wheel are regarded to be independent rigid bodies and have their own turn centers which reflect respective steering motions and responses. Since the suspension is the link between vehicle body and wheels, the consistence between the sprung mass turn center and the wheel turn center reflects the effect and performance of the suspension system. Firstly, the concept and appropriate calculation method of WTC and SPTC are developed. Then the degree of inconsistence between WTC and SPTC and the time that they achieve consistence, when the vehicle experiences from transient steering to steady steering state, are proposed to evaluate suspension performance. The suspension evaluation tests are conducted under different vehicle velocities and lateral accelerations by using CarSim software. The simulation results show that the inconsistence of steering motion between vehicle body and wheels are mainly at high speeds and low lateral accelerations. Finally, based on the proposed evaluation indexes, the influences of different suspension characteristic parameters on suspension performance and their matches to improve steering coordination are discussed. The proposed wheel turn center method provides a guidance and potential application for suspension evaluation and optimization.

Room temperature nonlinear mass sensing based on a hybrid spin-nanoresonator system

We present a room temperature nonlinear mass sensing based on a hybrid spin-nanoresonator system with the microwave pump–probe technique and the spin readout technique, which includes a single spin of nitrogen–vacancy (NV) center in diamond and a nanomechanical cantilever. The resonance frequency of the nanoresonator can be measured with the nolinear Kerr spectrum, and the parameters that influence the nolinear Kerr spectrum are also investigated. Further, according to the relationship between frequency shifts and variable mass attached on the nanoresonator, this system can also be used to detect the mass of DNA molecules with the nolinear Kerr spectrum. Benefiting from the single spin of the NV center in diamond has a long coherence time at 300 K, the hybrid system can realize room temperature mass sensor, and the mass response rate can reach 2600 zg/Hz.

Long-term Safety Observations on Side Effects and Com -plications of Non-surgical Sterilization by Chem ical In-stillation of the Fallopian Tubal

The present objective is to observe the side effects and complications of fem ale tubalsterilization by phenol-atabrinepaste (PAP) and phenolm ucilage (PM). 1 705 eligible w om en w ere divided random ly into tw o groups, 871 usinig PAP and 834 w om en using PM. Results: Thefeverratesw ere8.0and 4.4( P< 0.01 ) respec- tively in group PAP and group PM. Infection rates of the appendages w ere 2.3 and 1.2 respectively. The incidence of chem ical peritonitis, w ithin the lim its of pelvic cavity, w ere 1.1and 2.4respectively. Perforation of uterus, pelvic ab- scessand ectopicpregnancy w ere notfound during thisobservation. Slightabdom inal pain after the proceduresw ere 33.6and 30.8respectively. Slightvaginalbleed- ing after the procedure w as 23.2 and 18.0 respectively. Menstruation of the w om en w as not affected by the instillation. This five-year follow -up study neither show ed a positivePap testnor a potentialdeseasecaused by thesterilizing agents. This technique isa safe and efficientm ethod for fem ale sterilization.

Interaction between an Accelerated Mass in Straight Motion and a Hidden Energy Reservoir as a Strict Mathematical Consequence of Special Relativity

A. Einstein and H.A. Lorentz had found that the mass of an accelerated body traveling at relativistic velocity appears to depend on whether the acceleration is performed in the direction of motion or in a transverse direction. E.P. Epstein rejected this result in the “Annalen der Physik”;he rather postulated an additional force that turns up when the body is accelerated in the longitudinal direction. It can be shown that the concept of an increased longitudinal mass is based on a simple mathematical error. When correcting this error, it turns out that Epstein’s additional, hidden force is indispensable in order to avoid an inner inconsistency of Special Relativity. It does most of the total work absorbed by the moving object, and is thus responsible for most of the increase in its energy (=mass), given the speed attained is relativistic. In other words: While the total force on the body needed to maintain a constant acceleration a0 is “(1-v2/c2)-1ma0=m0(1-v2/c2)-3/2a0”, the technical force needed to maintain that acceleration amounts only to “ma0=m0(1 - v2/c2)-1/2a0”. The total energy of two objects that undergo a symmetrical, elastic head-on collision is therefore not conserved during the collision, thus requiring the involvement of a hidden reservoir of energy. This result is confirmed by calculations that use the concept of momenergy. The phenomenon of an apparent disappearance of energy has been noticed in particle physics already (target-experiment), but its consequences have been ignored. Instead, an explanation has been given (reduced “energy of the center of mass”) which is inconsistent and violates the relativity principle.

口腔正畸学中与力学相关的几个基本概念辨析

口腔正畸学与力学密切相关,在口腔正畸学相关教科书中涉及一些与力相关的概念,正畸医生正确理解这些概念对临床应用矫治力进行牙齿移动有着重要的指导意义。本文从力学角度对正畸学涉及的有关力的相关概念进行辨析,以期规范学术概念的表述,有利于口腔医学生的学习理解以及交叉学科的交流。

Discovery &Proofs of a Nucleus of Mass and Charge in the Photons/Quantum Particles

This work discovers and proves that all the photons/quantum particles have a “Nucleus of mass and charge.” The nucleus is located off-center in the particles. The constructive, destructive and intermediate Interference phenomena decisively discover and prove the presence of only one nucleus of the mass located off-center in a photon, like an atomic nucleus. The mass in the nucleus of a photon develops varying forces to move the photon as a wave. The Wave-Particle Duality is the most significant proof of such a nucleus of mass. The formation of an electromagnetic wave by a photon proves the presence of a charge in the nucleus of the photon. The Quantum Theory, developed about 100 years back, simplified the understanding of matter and energy at the atomic/subatomic levels. However, the Quantum Theory remains incomplete and cannot explain even a single quantum phenomenon. The New Quantum Theory, developed in the year 2012, is based on the similarity of an atomic nucleus as well as the solar system with the Sun as its nucleus of the mass and the charge. The New Quantum Theory explains all the Quantum Phenomena and matches with the Classical Mechanics as well as the Theory of Electromagnetism. The experiments described in this work, using high precision instruments, determine the mass, the charge and the diameter of a photon/quantum particle.

利用点云处理的实时的类别级位姿估计

针对传统的视觉算法无法准确地测量物体3D质心和尺寸、无法检测数据集中未出现过的物体等问题,提出一种基于点云的类别级物体质心与位姿估计算法.首先通过2D分割算法对物体待检测区域进行分割,并通过BlendMask提高实时性;然后将分割区域生成点云,并结合先验形状输入到神经网络中重建物体模型;最后输出一个变形场以及对应矩阵,并通过Umeyama算法对物体进行位姿估计.实验结果表明,所提算法达到了较高的精度;在质心估计方面也优于包络盒中心作为质心的算法;实时速率达到了13帧/s.在GPUNVIDIA2060上进行仿真实验,证明了所提算法计算的质心优于对比算法,以及该算法的准确性及可靠性.

水田动力底盘逆向建模与质心验证——基于Geomagic Design X

针对目前农业机械仿真和优化模型精度不高的问题,提出了一种构建精确模型的逆向建模方法。应用光学扫描仪采集点云数据,基于Geomagic Design X处理点云数据并重构零部件模型,在SolidWorks中完成水田动力底盘的装配。以VP6D-CQ型水田动力底盘为例,将测得的实际质心位置与所建的模型质心位置进行比较,并对提出的逆向建模方法进行了试验验证以及误差分析。结果表明:总质量、x坐标、y坐标、z坐标的误差值分别为4.55%、3.62%、2.23%、4.81%,误差值均在5%内。此方法可构建准确的三维模型,为后续仿真优化数据精确性奠定了基础,与传统的研发相比较,可缩短农业机械研发周期、降低设计成本。

县级融媒体中心助力基层社会治理的路径探析

基层治理是实现我国国家治理体系和治理能力现代化的核心环节之一。在基层治理实践中,县级融媒体中心的发展稳步推进成为引导群众和服务群众、促进基层社会治理现代化的关键因素。文章以基层治理的视角探索县级融媒体中心的功能定位,揭示其在推动基层社会治理过程中所遭遇的实际困难,并提出有效策略,以便提升基层治理效率。

关于魔力弹簧的收缩时间和上端运动问题

针对有关魔力弹簧研究中的几个问题进行探讨和澄清.建立了预收缩力弹簧的模型,推出其形变规律.根据质心运动定理,导出这种弹簧自由下落时,收缩到原长所用的时间、其上端的运动方程和速度公式.研究表明,对于通常演示所用的魔力弹簧,在自由下落时的收缩阶段,其上端不是作匀速直线运动.

石英挠性加速度计量程提高技术研究

为提高石英挠性加速度计的量程,分析了石英挠性加速度计量程受限机理,确认电磁反馈力与质量摆质心不重合是加速度计量程受限的主要原因。在此基础上,采用减小加工与装配误差和提高质量摆抗扭刚度的方法来提高石英挠性加速度计量程,并通过样机验证了该技术措施的有效性。

基于质心定标机动信号估计GRACE-FO卫星激光测距系统TTL耦合系数

GRACE-FO卫星搭载的激光测距系统(LRI)能够以纳米级的精度测量星间距离,LRI测距误差低频部分最大噪声源来自于TTL耦合噪声.TTL耦合噪声源于卫星姿态变化与质心(CoM)和三面镜顶点(VP)偏差产生的耦合效应.本文采用线性估计模型,并利用卫星在质心定标阶段的机动信号数据,基于不同方向的子机动,采用整体参数估计和独立参数估计共三种参数估计策略,获得了合理的TTL耦合系数,结果表明TTL耦合系数满足200 um·rad^(-1)的设计指标要求.另外,将TTL耦合系数换算为质心和三面镜顶点(VP-CoM offset)偏差,可间接获得卫星质心偏差估计结果序列,且该结果序列与基于加速度计的估计结果(卫星质心与加速度计检验质量块的偏差,ACC-CoM offset)序列吻合较好,表明该方法可作为GRACE-FO卫星质心偏差估计的补充方法.