Model-independent determination on H_0 using the latest cosmic chronometer data

We perform the updated constraints on the Hubble constant H_0 by using the model-independent method, Gaussian processes.Utilizing the latest 30 cosmic chronometer measurements, we obtain H_0= 67.38 ± 4.72 km s~(-1)Mpc~(-1), which is consistent with the Planck 2015 and Riess et al. analysis at 1σ confidence level. Different from the results of Busti et al. by only using 19 H(z) measurements, our reconstruction results of H(z) and the derived values of H_0 are insensitive to the concrete choice of covariance functions of Matern family.     

Entanglement distribution using three-mode separable state with imperfect equipments

We show a scheme to distribute the entanglement by using three-mode separable Gaussian state prepared with imperfect equipments.The scheme achieves the aim that the entanglement is distributed between two distant parties with only Gaussian operations and linear optics elements.Moreover,we analyse the logarithmic negativity of the entanglement shared between the two parties when the systems are imperfect and arrive at the conclusion that the logarithmic negativity is asymptotically stable with fluctuations within a certain space range.     

Precise orbit determination of a maneuvered GEO satellite using CAPS ranging data

Wheel-off-loadings and orbital maneuvers of the GEO satellite result in additional accelerations to the satellite itself. Complex and difficult to model, these time varying accelerations are an important error source of precise orbit determination (POD). In most POD practices, only non-maneuver orbital arcs are treated. However, for some applications such as satellite navigation RDSS services, uninterrupted orbital ephemeris is demanded, requiring the development of POD strategies to be processed both during and after an orbital maneuver. We in this paper study the POD for a maneuvered GEO satellite, using high precision and high sampling rate ranging data obtained with Chinese Area Positioning System (CAPS). The strategy of long arc POD including maneuver arcs is studied by using telemetry data to model the maneuver thrust process. Combining the thrust and other orbital perturbations, a long arc of 6 days’ CAPS ranging data is analyzed. If the telemetry data are not available or contain significant errors, attempts are made to estimate thrusting parameters using CAPS ranging data in the POD as an alternative to properly account for the maneuver. Two strategies achieve reasonably good data fitting level in the tested arc with the maximal position difference being about 20 m. Supported by the National Natural Science Foundation of China (Grant No. 10703011) and the Science & Technology Commission of Shanghai Municipality of China (Grant No. 06DZ22101)     

Controlled three-party communication using GHZ-like state and imperfect Bell-state measurement

We present a controlled three-party communication protocol using Greenberger-Horne-Zeilinger (GHZ)-like state and imperfect Bell-state measurement. Using the idea of controlled quantum teleportation, it can realize the secret information transmission between the legitimate participants under the control of the controller. It needs no unitary operation to recover the original state for the receiver, and it saves half of communication cost publicized by the sender. The order rearrangement of particles and data block transmission ensure the security of communication. With imperfect Bell-state measurement, it is tolerant of some noise effects and is feasible by using the present optical technique.     

Autonomous satellite constellation orbit determination using the star sensor and inter-satellite links data

A method of autonomous orbit determination for a satellite constellation using a star sensor combined with inter satellite links(ISLs) is studied.Two types of simulated observation data,Three-Satellite Constellation ISLs and background stellar observations by a CCD star sensor,are first produced.Based on these data,an observation equation is built for the constellation joint autonomous orbit determination,in which the simulations are run.The accuracy of this method with different orbital determination model...     

Damage detection in beams using vibratory power estimated from the measured accelerations

While there have been several analytical studies to estimate the vibratory power of damaged structures, only a few attempts have been tried to identify the damage for practical implementations. In order to understand the characteristics of the vibratory power in damaged structures, it is necessary to trace the time histories of the instantaneous power in the vicinity of the damage. The spatial distribution of the vibratory power should also be investigated, and a proper damage index is required to diagnose the damage. In this paper, a practicable local damage detection method is proposed using the vibratory power estimated from the accelerations measured on the damaged beam structure. A new damage index is defined based on the proposed damage detection method and is applied to identify the structural damage. Numerical simulation and experiment are carried out on a beam to confirm the validity of the proposed method. In the experiments, the damage considered as an open crack such as slit inflicted on the top surface of the beam. Changes in the vibratory power of the damaged beam are investigated, and the results show that the proposed method identifies successfully the structural damage in the beam.     

Effects of imperfect pulses on dynamical decoupling using quantum trajectory method

The dynamical decoupling(DD) method is widely adopted to preserve coherence in different quantum systems. In the case of ideal pulses, its effects on the suppression of noise can be analytically described by the mathematical form of filter function. However, in practical experiments, the unavoidable pulse errors limit the efficiency of DD. In this paper,we study the effects of imperfect pulses on DD efficiency based on quantum trajectories. By directly generating a pseudo noise sequence correlated in time, we can explore the performance of DD with different pulse errors in the typical noise environment. It shows that, for the typical 1/f noise environment, the phase error of operational pulses severely affects the performance of noise suppression, while the detuning and intensity errors have less influence. Also, we get the thresholds of these errors for efficient DD under the given experimental conditions. Our method can be widely applied to guide practical DD experimental implementation.     

Exact solution of general-relativity equations for vibratory collapse

In our previous article (cited as [A]) general requirements were formulated for the solutions of the general-relativity equations that follow from the geometry in the large and from the requirement that the origin be physically realizable [1]. In this article an exact self-consistent equation is described that takes full account of these requirements. The self-consistency is constant with respect to the volume density in the case of a dustlike ball [A17]. Although the self-consistent solution is of measure zero, it enables one to judge the properties of a wide class of solutions as shown by the experience of hydrodynamics.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 90–98, July, 1977.     

Quantum secure direct communication with an untrusted Charlie using imperfect measurement devices

正Quantum secure direct communication (QSDC) is a branch of quantum communication that transmits messages directly, rather than via a cryptographic key, in the quantum form [1-3]. As communication security becomes ever important today, the early use of quantum-proof cryptography is considered capable of minimizing the future exposure [4]. While quantum key distribution is regarded as such an approach, the potential of QSDC is also worth noting [4], and its rapid development has been witnessed in recent years [5-10].     

Inverse ultrasonic determination of imperfect interfaces and bulk properties of a layer between two solids

A method for determination of the complete set of physical, geometrical, and interfacial properties of an isotropic layer embedded between two known solids is discussed. These properties are: Lamé elastic moduli, density and thickness of the layer, and complex normal and transverse interfacial stiffnesses between the layer and the substrates. The properties are combined in the form of eight nondimensional parameters, which are determined from experimental reflection spectra at two incident angles: normal and oblique. The conditions for simultaneous determination of bulk layer properties and the interface normal and transverse springs with losses and the stability of the inversion method against data scatter are addressed. The inversion model is validated by experiment on normal and angular ultrasonic reflectivity from a layer between two semispaces in dry mechanical contact and from an environmentally degraded adhesive joint. The layer properties were measured independently, showing good agreement with the reconstructed results.     

Measurement of the energy dissipated in the hand and arm whilst using vibratory tools

Acceleration levels during hand-held grinding have been measured. By controlling the input to a vibration shaker the same acceleration levels were introduced into a specially designed handle gripped by a human hand. From measurements of force, acceleration and phase the power dissipated in the hand was calculated in third-octave bands. Approximate agreement was achieved with power dissipation estimates obtained from the acceleration alone by assuming the hand-arm system to be a linear, single degree of freedom system. The power dissipated is proposed as an important parameter affecting vibration-induced white finger.     

The thermodynamic limit for an imperfect Boson gas

We give a rigorous treatment in the infinite volume limit of a model Hamiltonian representing an imperfect Boson gas. In particular we obtain the exact expression for the mean particle density in the infinite volume limit as a function of the chemical potential, and show that the density function has a singularity at the critical density for Bose-Einstein condensation. We prove that, unlike the ideal Boson gas, the imperfect Boson gas has the same behaviour in the infinite volume limit for the grand canonical ensemble as for the canonical ensemble, and is moreover stable under small perturbations. We finally exhibit the possibility of ordinary condensation and prove that a system in an intermediate situation between two pure phases consists of a simple mixture of the two phases involved.     

Stability regions for Mathieu equation with imperfect periodicity

We consider a mean square stability for Mathieu equation with a random phase modulation in parametric excitation. An efficient numerical scheme is proposed for obtaining the stability charts for this equation. The influence of the random phase modulation on the shape of parametric resonance regions is studied. It is found that this influence can lead to stabilization under some conditions. A comparison with a case of Gaussian parametric excitation is presented.     

非理想正交反射镜消偏性能的模拟研究

通过建立非理想正交反射镜改变光线的几何模型,研究正交金属反射镜的消偏性能。模拟计算结果显示：在0.4μm～10μm波段内,非理想正交镀银反射镜的线偏振灵敏度优于铝、金等正交反射镜,且对光束偏振度的改变最小,因此正交镀银反射镜在高精度偏振遥感探测中值得广泛应用;若把角度误差控制在0.5°内,则正交镀银反射镜的偏振特性对偏振遥感器的辐射度和偏振度影响很小,具有较好的消偏性能。     

Snake's perspective on heat: reconstruction of input using an imperfect detection system

Two groups of snakes possess an infrared detection system that is used to create a heat image of their environment. In this Letter we present an explicit reconstruction model, the "virtual lens," which explains how a snake can overcome the optical limitations of a wide aperture pinhole camera, and how ensuing properties of the receptive fields on the infrared-sensitive membrane may explain the behavioral performance of this sensory system. Our model explores the optical quality of the infrared system by detailing how a functional representation of the thermal properties of the environment can be created. The model is easy to implement neuronally and agrees well with available neuronal, physiological, and behavioral data on the snake infrared system.     

Characterizing the curvature and its first derivative for imperfect fluids

The curvature tensor and its derivatives up to any order can be covariantly characterized by a minimal set of spinor quantities. On the other hand it might be useful, particularly in cosmology, to describe the geometry of a spacetime in a (1+3) formalism, based on an invariantly defined fluid velocity. In this work, we consider an imperfect fluid possessing both isotropic and anisotropic pressure. For these fluids, we determine the (1+3) matter terms of the curvature as well as the parts of the first order covariant derivative of the curvature (\(\nabla R\)) determined pointwise by the matter via the Bianchi identities. Explicit relations between the set of such terms obtained from the (1+3) and spinor decomposition of \(\nabla R\) are given. We show that in both sets there are 36 independent terms.