Novel method for simultaneous measurement of film thickness and mass fraction of urea–water solution

Quantitative knowledge of the film thickness and mass fraction of the urea-water solution is very crucial in many practical applications. Film thickness or mass fraction can only be determined individually by conventional measurement techniques. We develop a novel measurement method to measure the film thickness and mass fraction of ure~water solution simultaneously. The absorption coefficients of urea-water solution （5 50 wt%） are measured, a pair of optimized wavelengths is then chosen to achieve high measurement sensitivity. Cross validation is also performed and uncertainties of the technique are smaller than 0.68% for thickness measurements and 1.86% for mass fractions.     

Octupole Deformations of Even-Even Rn,Th, and U Nuclei in Relativistic Mean Field Theory

The octupole deformations and other ground state properties of even-even Rn, Th and U isotopes are investigated systematically within the framework of the reflection asymmetric relativistic mean field （RAS-RMF） model. The calculation results reproduce the binding energies and the quadrupole deformations well. The calculation results indicate these nuclei at ground states evolve from neaxly-spherical （N = 130） shape to quadrupole deformation shape with the increase of the neutron number. It is also found that among the Rn isotopes, only^222,224 Rn axe oetupole deformed and the octupole deformations for them are small. However, more nuclei （N ≌ 134 148） in Th and U isotopes are octupole deformed and the octupole deformations for some of them are significant （｜β3｜- 0.1 or even larger）.     

Nuclear Hexadecapole Deformation Effects on the Production of Super-Heavy Elements

We investigate the effects of the nuclear hexadecapole deformations on the interaction potentials between nuclei, the driving potentials and the fusion probabilities for some cold fusion reactions leading to super-heavy elements. It is found that nuclear hexadecapole deformations change significantly the structure of the driving potentials and the fusion probabilities for some reaction channels.     

Triaxiality and shape coexistence in the A ～ 30 “island of inversion”nuclei

Understanding the properties of nuclei inside "island of inversion" is still an interesting issue. Based on a simple Nilsson model with a new set of isospin-dependent parameters, and with non-axial deformations considered, we have performed three-dimensional potential-energy-surface calculations for Ne, Na, Mg and Al isotopes that are claimed to be in or nearby the A～30 island of inversion". It is found that shape coexistence and triaxial deformation(or softness) exist in these nuclei. Large deformations are obtained by the improved Nilsson parameters, which explains the observed large electric quadrupole transition probabilities. The large deformations happening in30 Ne,31Na,32 Mg and33Al indicate the quenching of the spherical N = 20 neutron shell gap. The calculations of nuclear binding and two-neutron separation energies have been also improved with the isospin-dependent parameters and the inclusion of the non-axial deformation degree of freedom.     

Upgrade of beam energy measurement system at BEPC-Ⅱ

The beam energy measurement system is of great importance for both BEPC-Ⅱ accelerator and BES-III detector. The system is based on measuring the energies of Compton back-scattered photons. In order to meet the requirements of data taking and improve the measurement accuracy, the system has continued to be upgraded, which involves the updating of laser and optics subsystems, replacement of a view-port of the laser to the vacuum insertion subsystem, the use of an electric cooling system for a high purity germanium detector, and improvement of the data acquisition and processing subsystem. The upgrade system guarantees the smooth and efficient measurement of beam energy at BEPC-II and enables accurate offline energy values for further physics analysis at BES-Ⅲ.     

Measurement of out-of-plane deformation of curved objects with digital speckle pattern interferometry

Digital speckle pattern interferometry(DSPI) is a high-precision deformation measurement technique for planar objects. However, for curved objects, the three-dimensional(3 D) shape information is needed in order to obtain correct deformation measurement in DSPI. Thus, combined shape and deformation measurement techniques of DSPI have been proposed. However, the current techniques are either complex in setup or complicated in operation. Furthermore, the operations of some techniques are too slow for real-time measurement. In this work, we propose a DSPI technique for both 3 D shape and out-of-plane deformation measurement. Compared with current techniques, the proposed technique is simple in both setup and operation and is capable of fast deformation measurement. Theoretical analysis and experiments are performed. For a cylinder surface with an arch height of9 mm, the error of out-of-plane deformation measurement is less than 0.15 μm. The effectiveness of the proposed scheme is verified.     

Phenomenological study of ■ decays

The measurement of decay parameters is one of the important goals of particle physics experiments, and the measurement serves as a probe to search for evidence of CP violation in baryonic decays. The experimental results will aid in advancing existing theoretical research and establishing new experimental objectives. In this study,we formulate the asymmetric parameters that characterize parity violation, and then derive formulas for the measurement of CP violation. The formulae for the joint ang...     

Total Routhian surface calculations of triaxial or γ-soft properties in even-A N = 76 isotones with 54≤Z≤68

Total Routhian surface(TRS) calculations for even–even N = 76 isotones with 54 Z 68 have been performed in three-dimensional(β2,γ,β4) deformation space. Calculated results of the equilibrium deformations are presented and compared with other theoretical predictions and available experimental data. The behavior of collective angular momentum shows the neutron rotation-alignment is preferred in the lighter N = 76 isotones, while for the heavier ones the proton alignment is favored. Moreover, multi-pair nucleon alignments and their competition(e.g.,in144Er) are predicted. It is pointed out that these nuclei in the N =76 isotonic chain exhibit triaxiality or γ softness in high-spin states as well as ground states. Based on deformation-energy curves with respect to axial and non-axial quadrupole deformations, the shape instabilities are evaluated in detail and predicted, particularly in γ direction.Such instabilities are also supported by the odd- and even-spin level staggering of the observed γ bands, which is usually used to distinguish between γ-rigid and γ-soft asymmetry.     

Effect of coating thickness on the calibration and measurement uncertainty of a wide-band liquid crystal thermography

<正>The liquid crystal thermography is a high-resolution and non-intrusive optical technique for full-field temperature measurement.We present detailed calibration data for a wide-bandwidth thermochromic liquid crystal(TLC) to investigate the effect of the coating thickness on the hue-temperature characteristics and the measurement uncertainty of the TLC.It is found that the coating thickness has appreciable effect on the TLC hue-temperature curve.For TLC coatings with the thickness over 20μm,a thicker TLC coating shows a relatively smaller measurement uncertainty,but the effect of the coating thickness is non-distinctive on the measurement uncertainty.     

QUANTITATIVE MEASUREMENT OF THE ULTRASONIC STRESSES IN A TRANSPARENT SOLID BY THE PHOTOELASTIC METHOD

A photoelastic method for the measurement of the difference between principal stresses is extendedto the measurement of a two dimensional ultrasonic stress.The stress of an ultrasonic plane pro-gressive wave or cylindrical progressive wave at any point in a transparent solid can be determined. The method of the measurement and its principle is presented,including the derivation of therelation between the principal stresses difference and the principal stresses for plane or cvlindricalprogressive wave.A practical example of measurement is described,its results being compared withthose of an electrical method.     

Measurement of sensitivity of transducer in the field of NDT by the reciprocity technique

The sensitivity of a transducer should be an important characteristic inthe field of NDT.But so far,no method for this measurement of the sensitivity of atransducer applied to the ultrasonic flaw detection is available.In this paper thetransducer is regarded as a plane source and the reciprocity parameter under thecondition of the far field is derived.We have calibrated the sensitivity of ultrasonictransducers with the reciprocity technique in the solid sample.The experimentsshow and confirm that the transmitting and receiving sensitivities of the transducerapplied to NDT can be exactly measured.The precision of the measurement is with-in ± 1dB under a certain coupling condition.     

Design of differential optical system of in-plane remote displacement measurement

In this paper, an optical system for in-plane remote displacement measurement is brought forward. The remarkable characteristic of this optical system is to use a big aperture lens to focus the waists of two Gauss beams on a scatter which have been expanded and collimated, so good laser Doppler signals and high measurement accuracy are achieved. The experiments prove that the measurement system consisting of this optical system, a lock-in amplifier and a digital filter can be used to measure the in-plane displacement of scatters in distance of 50 m with the relative accuracy of 1%.     

Pascal Realization by Comb-Spectral-Interferometry Based Refractometer

To break through the limitations of existing pressure standards, which rely on the gravity and toxic mercury,the national metrological institutes prefer a quantum-based pressure standard. Combining the ideal gas law with helium refractivity measurement, we demonstrate a scheme for the realization of the pressure unit. The refractometer is based on a spectral interferometry with an optical frequency comb and a double-spaced vacuum cell. Through fast Fourier transform of the spectral interferograms of the two beams propagating inside and outside the vacuum cell, the helium refractivity can be obtained with a combined standard uncertainty u(n) of2.9 × 10~(-9). Moreover, the final u(n) is ~8.7 × 10~(-6) in a measurement range of several megapascals(MPa). Our apparatus is compact, fast(15 ms for one single measurement) and easy to handle. Furthermore, the measurement uncertainty will be improved to ~1 × 10~(-9) or lower if a VIPA-based spectrometer is used. The value of u(p) will thus increase to 3 × 10~(-6) or better in several MPa.     

Measurement errors of ultrasonic velocity and attenuation due to nonparallelness of specimen faces

The measurement errors due to nonparallelness of specimen faces in the ultrasonic velocity and attenuation coefficient measured by the pulse reflection method in VHF range have been investigated theoretically, and the theoretical expressions for estimating these measurement errors are given. It has also been shown that, the attenuation coefficient error is depending on both the nonparallelness angle of specimen faces and the ultrasonic frequency, but the velocity error is only depending on the former. Furthermore, for pure silica glass specimen it is estimated that, in VHF range in order to insure that the attenuation coefficient and velocity errors due to nonparallelness of specimen faces are less than 10% and 0.01%, respectively, the nonparallelness angle of specimen faces must be less than 10 s and 40 s correspondingly.     

Integral colorimeter based on compound LED illumination

Traditional integral colorimeters use tungsten–halogen or xenon lamps for illumination,as well as correcting filters to make the instrument's spectral response meet the Luther condition.This structure causes the instruments to have relatively higher error and poor repeatability.Thus,this letter proposes a new measurement design that uses compound LEDs as the instrument's measurement light source.The new design adjusts the instrument's spectral response by modifying the spectra of the compound LEDs.A compound LED light source is designed for integral colorimeters,and an experiment is conducted to evaluate the performance of the integral colorimeter.Experiments show that the design effectively reduces the error of integral colorimeters.     

Theory of Z-scan technique using Gaussian-Bessel beams with a phase object

This paper reports the theoretical study of combining Z-scan technique with Gauss-Bessel (GB) beams beside a phase object (PO) to measure the third-order nonlinear susceptibility components.By using this method,the sign of refractive index which depends on the shape of the close aperture Z-scan curve can be easily determined.Meanwhile,the magnitude of nonlinear coefficients can also be deduced by theoretical fit.The proposed method is advantageous for high sensitivity and imposes a lower stress in the cases of fragile materials,since small pulse energy is enough for the measurement of nonlinear coefficients.Predictions of the models are compared with Gaussian Z-scan measurement and GB Z-scan measurement.By using GB beams with a PO,the sensitivity of Z-scan measurements is found to be a factor of over 60 times greater than for Gaussian beams and 2 times greater than for Gaussian-Bessel beams.     

Generalization of α-Decay Cluster-Model to Nuclei Near Spherical and Deformed Shell Closures

The cluster model of a-decay is extended to the regions around doubly magic spherical nucleus ^208Pb and around deformed shell closure ^270Hs, respectively. The effects of spherical shell closures (N=126 and Z=82) on α-decay are investigated by introducing an N-dependent α-preformation factor and a Z-dependent one inspired by a microscopic model. Good agreement between the theoretical a-decay half-lives and the measured ones is obtained for the spherical nuclei near the doubly magic nucleus ^208Pb, where the nuclear shell effect is included in the expression of α-preformation factor. The cluster model is also generalized for the decay of deformed nuclei. The branching ratios of α-decays from the ground state of a parent nucleus to the ground state (0^ ) of its deformed daughter nucleus and to the first excited state (2^ ) are calculated in the framework of the cluster model. The results indicate that a measurement of α spectroscopy is a feasible method to extract the information of nuclear deformation of superheavy nuclei around the deformed nucleus ^270Hs.     

A new representation and probabilistic teleportation of an arbitrary and unknown N-particle state

A new representation of an arbitrary and unknown N-particle state is presented at first. As an application, a scheme for teleporting an arbitrary and unknown N-particle state is proposed when N pairs of two-particle non- maximally entangled states are utilized as quantum channels. After Alice （sender） makes Bell-state measurement on her particles, Bob （recipient） introduces an auxiliary particle and carries out appropriate unitary transformation on his particle and the auxiliary particle depending on classical information from Alice. Then, von Neumann measurement that confirms whether the teleportation succeeds or not is performed by Bob on the auxiliary particle. In order to complete the teleportation, another N-1 times operations need to be performed which are similar to the above ones. It can be successfully realized with a certain probability which is determined by the product of the smaller coefficients of non-maximally entangled pairs. All possible unitary transformations are given in detail.