Syzygy Effects Studies Performed Simultaneously with Foucault Pendulums and Torsinds during the Solar Eclipses of 13 November 2012 and 10 May 2013

Several simultaneous observations are presented of Syzygy effects during two solar eclipses, performed with torsinds and Foucault pendulums. The experiments/measurements were of a simple nature, conducted in several of places in Romania and Ukraine. It is shown that during Syzygy effects both the torsind and the Foucault pendulum exhibit specific reactions: the torsind’s disk is rotated, whereas the direction of the swing plane, the period, the eccentricity and the chirality of the ellipse of oscillation of the Foucault pendulum are all altered. We term all these perturbations “Syzygy effects” and found that they take place even when the devices are in locations where the eclipse is not visible and even when they are underground. An unusual time shifts?between the responses of the devices and the maximum phase of the eclipse is detected. The importance of simultaneous simple observations of astronomical phenomena using these two devices of fundamentally different types is emphasized.

Intelligent Control on Three-Stage Inverted Pendulums

In this paper, a new intelligent control method is introduced, which combines stipulations, optimal control method with knowledge based control. Using nonlinear programming method and expert experience for the complicated nonlinear object, the good control result can be achieved. The effect of this method is shown by a simulation of three stage inverted pendulums.

THE LIMIT CYCLE BIFURCATIONS OF A WHIRLING PENDULUM WITH PIECEWISE SMOOTH

This paper deals with the problem of limit cycles for the whirling pendulum equation x=y,y=sin x(cosx-r)under piecewise smooth perturbations of polynomials of cos x,sin x and y of degree n with the switching line x=0.The upper bounds of the number of limit cycles in both the oscillatory and the rotary regions are obtained using the Picard-Fuchs equations,which the generating functions of the associated first order Melnikov functions satisfy.Furthermore,the exact bound of a special case is given using the Chebyshev system.At the end,some numerical simulations are given to illustrate the existence of limit cycles.

Study on a conical bearing for acceleration-sensitive equipment

Seismic isolation effectively reduces seismic demands on building structures by isolating the superstructure from ground vibrations during earthquakes.However,isolation strategies give less attention to acceleration-sensitive systems or equipment.Meanwhile,as the isolation layer’s displacement grows,the stiffness and frequency of traditional rolling and sliding isolation bearings increases,potentially causing self-centering and resonance concerns.As a result,a new conical pendulum bearing has been selected for acceleration-sensitive equipment to increase self-centering capacity,and additional viscous dampers are incorporated to enhance system damping.Moreover,the theoretical formula for conical pendulum bearings is supplied to analyze the device’s dynamic parameters,and shake table experiments are used to determine the proposed device’s isolation efficiency under various conditions.According to the test results,the newly proposed devices have remarkable isolation performance in terms of minimizing both acceleration and displacement responses.Finally,a numerical model of the isolation system is provided for further research,and the accuracy is demonstrated by the aforementioned experiments.

Reduced-Order Observer-Based LQR Controller Design for Rotary Inverted Pendulum

The Rotary Inverted Pendulum(RIP)is a widely used underactuated mechanical system in various applications such as bipedal robots and skyscraper stabilization where attitude control presents a significant challenge.Despite the implementation of various control strategies to maintain equilibrium,optimally tuning control gains to effectively mitigate uncertain nonlinearities in system dynamics remains elusive.Existing methods frequently rely on extensive experimental data or the designer’s expertise,presenting a notable drawback.This paper proposes a novel tracking control approach for RIP,utilizing a Linear Quadratic Regulator(LQR)in combination with a reduced-order observer.Initially,the RIP system is mathematically modeled using the Newton-Euler-Lagrange method.Subsequently,a composite controller is devised that integrates an LQR for generating nominal control signals and a reduced-order observer for reconstructing unmeasured states.This approach enhances the controller’s robustness by eliminating differential terms from the observer,thereby attenuating unknown disturbances.Thorough numerical simulations and experimental evaluations demonstrate the system’s capability to maintain balance below50Hz and achieve precise tracking below1.4 rad,validating the effectiveness of the proposed control scheme.

THE SOLUTIONS OF FORCED PENDULUMS EQUATION WITH SMALL DAMPING

We prove the existence of an arbitrarily large number of periodic solutions of pendulum equation with small damping.

Measurement of remanent magnetic moment using a torsion pendulum with single frequency modulation method

In Tian Qin spaceborne gravitational-wave detectors, the stringent requirements on the magnetic cleanliness of the test masses demand the high resolution ground-based characterization measurement of their magnetic properties. Here we present a single frequency modulation method based on a torsion pendulum to measure the remanent magnetic moment mr of 1.1 kg dummy copper test mass, and the measurement result is(6.45 ± 0.04(stat) ± 0.07(syst)) × 10^(-8)A · m^(2). The measurement precision of the mr is about 0.9 n A · m^(2), well below the present measurement requirement of Tian Qin. The method is particularly useful for measuring extremely low magnetic properties of the materials for use in the construction of space-borne gravitational wave detection and other precision scientific apparatus.

Computing of LQR Technique for Nonlinear System Using Local Approximation

The main idea behind the present research is to design a state-feedback controller for an underactuated nonlinear rotary inverted pendulum module by employing the linear quadratic regulator(LQR)technique using local approximation.The LQR is an excellent method for developing a controller for nonlinear systems.It provides optimal feedback to make the closed-loop system robust and stable,rejecting external disturbances.Model-based optimal controller for a nonlinear system such as a rotatory inverted pendulum has not been designed and implemented using Newton-Euler,Lagrange method,and local approximation.Therefore,implementing LQR to an underactuated nonlinear system was vital to design a stable controller.A mathematical model has been developed for the controller design by utilizing the Newton-Euler,Lagrange method.The nonlinear model has been linearized around an equilibrium point.Linear and nonlinear models have been compared to find the range in which linear and nonlinear models’behaviour is similar.MATLAB LQR function and system dynamics have been used to estimate the controller parameters.For the performance evaluation of the designed controller,Simulink has been used.Linear and nonlinear models have been simulated along with the designed controller.Simulations have been performed for the designed controller over the linear and nonlinear system under different conditions through varying system variables.The results show that the system is stable and robust enough to act against external disturbances.The controller maintains the rotary inverted pendulum in an upright position and rejects disruptions like falling under gravitational force or any external disturbance by adjusting the rotation of the horizontal link in both linear and nonlinear environments in a specific range.The controller has been practically designed and implemented.It is vivid from the results that the controller is robust enough to reject the disturbances in milliseconds and keeps the pendulum arm deflection angle to zero degrees.

Rapid report of seismic damage to hospitals in the 2023 Turkey earthquake sequences

The seismic performance of medical systems is crucial for the seismic resilience of communities.The report summarizes the observed damage to twelve hospital buildings in the area affected by the MW 7.8 and MW 7.5 earthquakes on February 6,2023 in Turkey.They include five base-isolated buildings and seven fixed-base buildings in southcentral Turkey's seven most heavily affected provinces.By relating the post-quake occupancy statuses of the hospitals with the estimated seismic demands during the earthquake doublet,the report offers the following observations:(1)the base-isolated hospital buildings on friction pendulum bearings generally exhibited superior performance of achieving the goal of immediate occupancy and provided better protection for nonstructural elements than fixed-base counterparts did;(2)the fixed-base hospital buildings of reinforced concrete structures constructed after 2001 successfully achieved the goal of collapse prevention even under very high seismic demands;(3)some fixed-base hospitals also remained operational even if they were very close to the fault rupture and were subjected to higher-than-design-level earthquake ground motions.

Inexplicable Multi-Annual Astral Action on the Precession of Allais Pendulum: An Influence of the Solar System (and Especially of Jupiter?)

Between 1954 and 1961, Allais conducted 6 one-month observations of the azimuth of the plane of oscillation of a pendulum installed in his laboratory. That of 1958 also implemented a second pendulum, identical to the first, located 6 km away in an underground quarry. Although, over these 6 years, the average azimuth of each observation, the amplitude of the 24 h 50 min and 24 h waves, as well as certain other quantities, have evolved considerably, in 1958 their values were very close to those of the second pendulum. The analysis shows that these evolutions could only result from an action external to the pendulum, that no classical phenomenon seems to be able to explain, and which appears, at least mainly, to be an astral action. The evolution of the average azimuth of the pendulum and of the amplitudes of the 24 h and 24 h 50 min components can be decomposed into a component associated with the annual revolution of the Earth around the Sun, and a multi-annual component, whose harmonic 1 has a period which was estimated to 5.74 years. An action of Jupiter is an excellent candidate to explain a large part of the multi-annual action: everything happens as if there were an important action of the modulus of its declination on the multi-annual component, and an important daily action of its hour angle on the azimuth of the pendulum. We cannot exclude an action of the solar cycle, whose period was then about 11 years. The main results were obtained by Allais himself, but this was only published in his book “The Anisotropy of Space”, and remained very little known. Starting from the raw data of Allais, the author of this article found them again, and completed them on certain points.

The Extended Non-Elementary Amplitude Functions as Solutions to the Damped Pendulum Equation, the Van der Pol Equation, the Damped Duffing Equation, the Lienard Equation and the Lorenz Equations

In this paper, we define some non-elementary amplitude functions that are giving solutions to some well-known second-order nonlinear ODEs and the Lorenz equations, but not the chaos case. We are giving the solutions a name, a symbol and putting them into a group of functions and into the context of other functions. These solutions are equal to the amplitude, or upper limit of integration in a non-elementary integral that can be arbitrary. In order to define solutions to some short second-order nonlinear ODEs, we will make an extension to the general amplitude function. The only disadvantage is that the first derivative to these solutions contains an integral that disappear at the second derivation. We will also do a second extension: the two-integral amplitude function. With this extension we have the solution to a system of ODEs having a very strange behavior. Using the extended amplitude functions, we can define solutions to many short second-order nonlinear ODEs.

Project-Based Teaching in Control Theory Education Based on V-REP: A Cart Inverted Pendulum Case

This paper provides a teaching concept for control theory education based on Virtual Robot Experimentation Platform(V-REP).A cart inverted pendulum virtual physical model is developed on V-REP.Students must analyze,design,and implement a suitable controller for the cart inverted pendulum system using their knowledge of the control theory.Different from traditional experiment and numerical simulation,virtual experiment is safe and less constrained.Moreover,the experiment results are more intuitive and obvious.This study can improve students’interest in learning the control theory and help students understand the relevant content better.

Pendulum矫治器远中移动磨牙治疗Ⅱ类错的临床及头影测量评价

目的 :探讨Pendulum矫治器治疗Ⅱ类错牙合的临床疗效及对牙颌面的影响。方法 :应用Pendulum矫治器对18例平均年龄为 11.9岁的牙性Ⅱ类错牙合患者进行治疗 ,通过治疗前后的头影测量分析 ,评价其对牙颌面的影响。结果 :Pendulum矫治器能够远中移动上颌磨牙致磨牙关系为Ⅰ类或偏近中 ,未见开牙合及明显前牙支抗丧失。结论

可逆乘除法指令的设计与仿真

为解决可逆指令集PISA缺少乘法指令和除法指令的问题,提出一种通过可逆子过程实现乘除法指令的方法。研究PISA指令集中的现有指令,总结并概括使用可逆指令进行编程的方法和原则,分析设计可逆乘除法指令须遵守的约束,给出可逆乘除法指令的格式,分别使用可逆的原码一位乘和恢复余数法实现乘法指令和除法指令。在可逆指令集仿真平台上对实现的乘除法指令进行测试,测试结果表明,乘法指令和除法指令均逻辑可逆,在满足特定约束条件时互为逆指令。

改良Pendulum与改良Jones远移磨牙的对比分析

目的:探讨改良Pendulum矫治器、改良Jones装置推磨牙向远中的疗效。方法:选择22例轻中度前牙拥挤的安氏Ⅱ类错病例,介于拔牙和不拔牙矫治的边缘,所有病例被平均随机分配在2个组,分别采用2种装置推磨牙向远中,在治疗前后进行X线头影测量和模型测量分析,采用SPSS软件对数据进行分析。结果:2组远中移动效果均比较明显,但在移动速度、磨牙中央窝宽度差、前牙覆差、上颌第二前磨牙以及第一磨牙的倾斜度的统计分析上差异有统计学意义。结论:改良Pendulum矫治器J、ones装置均可有效地推上颌磨牙向远中移动,但改良Jones组磨牙向远中更少发生倾斜移动,矫治时间短,移动速度更快,对前牙支抗消耗相对较低。

HUMAN-IMITATING INTELLIGENT CONTROL AND TRIPLE INVERTED-PENDULUM

A 'Human-Imitating Intelligent Control Theory' with 'generalized reduction' and 'Human Imitating' concepts as its kernel is proposed. And a world puzzlein the control circles is solved successfully based on this theory. The puzzle is thewell-known 'triple inverted pendulum control' using a SINGLE motor. A human-imitating intelligent technique to control inverted pendulum is here described. The success. ful experimental results show that our control objective can be achieved without a precise mathematical model of the plant. Finally, general principles of designing complexautomatic control systems based on the human-imitating intelligent control theory areconcluded.

第六届中国大学生物理学术竞赛简讯

中国大学生物理学术竞赛（China Undergraduate Physicists’Tournament,简称CUPT）是中国借鉴国际青年物理学家锦标赛（International Young Physicists’Tournament,简称IYPT）模式创办的一项全国性物理类赛事.第六届中国大学生物理学术竞赛于2015年8月19日—24日在国防科学技术大学举行.

非线性振动、非线性波与Jacobi椭圆函数(续)

Succinct and efficient method to obtain analytic solutions of nonlinear vibrations and nonlinear waves by Jacobian elliptic functions are introduced. Important typical examples are given and explained, including simple pendulum, Duffing oscillator, cnoidal wave and solitary wave solutions of KdV equation, sine-Gordon equation, nonlinear Schrdinger equation, sech^2 profile solitons, kink and anti-kink solitons, breather, interaction of a kink and an anti-kink, and envelop solitons.