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An empirical L-band scintillation model for a mid-latitude station,Weihai, China during the low solar activity period

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Science China(Technological Sciences) 2019年第7期62卷 1182-1190页

作者： PRIYADARSHI Shishir ZHANG Qing-He WANG Yong Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment Institute of Space SciencesShandong University

Mid-latitude ionospheric scintillation has been studied in very poor proportion as compared to the equatorial and high latitude ionospheric scintillation. Mid-latitude ionospheric scintillations are often associated with either day time photo-ionization or due to the storm enhanced density. Using the phase screen model and the wave propagation theory in random media, we have identified the orientation of the ionospheric irregularities over Weihai with the local geomagnetic field. Amplitude and phase scintillation data observed using global positioning system(GPS) scintillation receiver deployed at the mid-latitude observation station Weihai, have been used along with K-index derived from the horizontal magnetic field component of the local magnetometer. The proposed model uses the scintillation indices relationship with the local K-index. We identified the scintillation dependence over local K-index during geomagnetic quiet and disturbed condition. This dependence coefficient is used on the real scintillation data for modeling. The presented scintillation model has been validated by comparing it to the real observations. The co-relation coefficient is more than 90% during the disturbed as well as quiet geomagnetic conditions.

关键词： mid-latitude ionosphere scintillation GPS global navigation satellite systems (GNSS)

Anomalous Variation of Beat Frequency in a Dual Frequency He-Ne Laser

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Chinese Physics Letters 2016年第2期33卷 51-54页

作者：刘维新孙明哲 Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment Institute of Space SciencesShandong University

The beat frequency in a dual frequency He-Ne laser varies while the resonant cavity length is tuned. As to the laser with two longitudinal modes, the variation amplitude is commonly less than 500 kHz, proven by experiments and theories. This study reveals an anomalous variation of the beat frequency when a piece of element is put into the cavity and is aligned with the laser axis. Consequently the variation amplitude couM reach 22 MHz, several dozen times larger than that without the intra-cavity element. This cannot be explained only by laser mode pulling and pushing effects. Some influencing factors are investigated experimentally, including the tilted angle of the element and the distance between its surface and cavity mirror. The qualitative analysis is discussed, which agrees with the experimental results.

关键词： of on as it or Anomalous Variation of Beat Frequency in a Dual Frequency He-Ne Laser in is

Period ratios for standing kink and sausage modes in magnetized structures with siphon flow on the Sun

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Research in Astronomy and Astrophysics 2016年第6期16卷 69-84页

作者： Hui Yu Shao-Xia Chen Bo Li Li-Dong Xia Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment Institute of Space SciencesShandong University

Standing oscillations with multiple periods have been found in a number of atmospheric struc- tures on the Sun. The ratio of the period of the fundamental to twice the one of its first overtone, P1/2192, is important in applications of solar magneto-seismology. We examine how field-aligned flows impact P1/2P2 of standing modes in solar magnetic cylinders. For coronal loops, the flow effects are significant for both fast kink and sausage modes. For kink modes, they reduce P1/2P2 by up to 17% relative to the static case even when the density contrast between the loop and its surroundings approaches infinity. For sausage modes, the reduction in P1/2P2 due to flow is typically ≤ 5.5% compared with the static case. However, the threshold aspect ratio, only above which can trapped sausage modes be supported, may increase dramatically with the flow magnitude. For photospheric tubes, the flow effect on P1/2P2 is not as strong. However, when applied to sausage modes, introducing field-aligned flows offers more possibilities in interpreting the multiple peri- ods that have recently been measured. We conclude that field-aligned flows should be taken into account to help better understand what causes the departure of P1/2P2 from unity.

关键词： magnetohydrodynamics (MHD) -- Sun: corona -- Sun: magnetic fields -- waves

Candidate chiral nuclei in bromine isotopes based on triaxial relativistic mean field theory

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Science China(Physics,Mechanics & Astronomy) 2019年第1期62卷 56-62页

作者： Bin Qi Hui Jia Chen Liu ShouYu Wang Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment School of Space Science and Physics Institute of Space Sciences Shandong University

Following the observation of candidate chiral doublet bands in ^(78,80)Br, triaxial deformations with corresponding configurations in odd-odd bromine isotopes have been investigated using adiabatic and configuration-fixed constrained triaxial relativistic-meanfield calculations with an aim of finding the boundary of chirality in the chain of Br isotopes. Several minima with triaxial deformation and the proper particle-hole configuration were obtained in ^(74,76,78,80,82)Br, where the chiral doublet bands have the possibility of occurrence. Furthermore, the possible existence of multiple chiral doublet(MχD) bands is demonstrated in ^(74,76,78,80,82)*** to explore the chirality and MχD properties of Br isotopes are conducted to verify the predictions.

关键词： chiral doublet bands relativistic mean field bromine isotopes

Alternating Parity Band in Octupole-Soft ^(140)Xe with Axial Vibrational-Rotational Model and Triaxial Rigid Rotor Model

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Chinese Physics Letters 2018年第10期35卷 9-13页

作者： Xiao Lu Bin Qi Shou-Yu Wang Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment School of Space Science and Physics Institute of Space Sciences Shandong University

Energies of the yrast positive-and negative-parity excited states in140 Xe are reproduced by two different models considering quadrupole-octupole deformations, namely the axial vibrational-rotational model and the triaxial rigid rotor model, and compared with the stable octupole-deformed222 Th. The origin of the energy difference between the opposite parity sequences is considered from two different mechanisms, the vibration in axial deformed energy minima and the rotation considering the effective triaxial deformation. The success of reproducing the data in both the models implies that these two mechanisms are equivalent on some level for the octupole-soft nuclei. By investigating the probability distributions for projection of total angular momentum in the triaxial rigid rotor model, it is found that such an energy difference is associated with the difference of orientation of the rotational axis.

关键词： Alternating Parity Band in Octupole-Soft Xe with Axial Vibrational-Rotational Model and Triaxial Rigid Rotor Model

Electromagnetic transitions in multiple chiral doublet bands

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Chinese Physics C 2016年第12期40卷 91-98页

作者： Hui Jia Bin Qi Shou-Yu Wang Shuo Wang Chen Liu Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment Institute of Space Sciences Shandong University Weihai 264209 China

Multiple chiral doublet bands （MχD） in the 80, 130 and 190 mass regions are studied by the model of γ=90°triaxial rotor coupled with identical symmetric proton-neutron configurations. By selecting a suitable basis, the calculated wave functions are explicitly exhibited to be symmetric under the operator A, which is defined as rotation by 90° about the 3-axis with the exchange of valance proton and neutron. We found that both M1 and E2 transitions are allowed between levels with different values of A, while they are forbidden between levels with same values of A. Such a selection rule holds true for MχD in different mass regions.

关键词： chiral doublet bands electromagnetic transition selection rule particle rotor model

Possible existence of chiral and multiple chiral nuclei in thallium isotopes

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Chinese Physics C 2022年第7期46卷 149-158页

作者： Rui-Ju Guo Xiao Lu Bin Qi Chen Liu Shou-Yu Wang Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment Institute of Space SciencesShandong UniversityWeihai 264209China

The chirality in thallium isotopes is investigated using the adiabatic and configuration-fixed constrained triaxial relativistic mean field theory. Several minima with prominent triaxial deformation and proper configuration,where the chiral doublet bands may appear, are obtained in odd-odd nucleiTl and odd-mass nucleiTl. Furthermore, the possible existence of multiple chiral doublet bands(MχD)is demonstrated inTl. As the chiral doublet bands inTl and MχD inTl have been observed experimentally, further experimental exploration for the chirality inTl and MχD in thallium isotopes is expected to verify the predictions.

关键词： chirality relativisticmean field theory thallium isotopes

Possible candidate nuclei for chirality-parity quartet bands

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Chinese Physics C 2018年第7期42卷 82-88页

作者： Chen Liu Shou-Yu Wang Bin Qi Hui Jia Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment Institute of Space Sciences Shandong University Weihai 264209 China

The potential energy surfaces of the even-even 68-92Se, 112-150Ba, and 208-230Ra isotopes are calculated using the macroscopic-microscopic method in a multidimensional space {αλ,μ} including quadrupole （λ=2, μ=0, 2） and octupole （λ=3, μ=0, 1, 2, 3） degrees of freedom. The calculated results show that the even-even isotopes 92Se, 112,114,144-150Ba and 220-228Ra can exhibit the coexistence of triaxial and octupole deformations, thereby leading to simultaneous chiral and reflected symmetry breaking. Therefore, chirality-parity quartet bands are expected in these and their neighboring odd-A/odd-odd nuclei.

关键词： chiral doublet bands shape coexistence chirality-parity quartet bands macroscopic-microscopic method

The photometric system of the One-meter Telescope at Weihai Observatory of Shandong University

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Research in Astronomy and Astrophysics 2014年第6期14卷 719-732页

作者： Shao-Ming Hu Sheng-Hao Han Di-Fu Guo Jun-Ju Du Shandong Provincial Key laboratory of Optical Astronomy and solar-terrestrial environment Institute of Space Sciences School of Space Science and Physics Shandong University

The one-meter telescope at Weihai Observatory （WHO） of Shandong University is an f/8 Cassegrain telescope. Three sets of filters are installed in a dual layer filterwheel that use Johnson-Cousins UBVRI, Sloan Digital Sky Survey u′g′r′i′z′ and Stomgren uvby. The photometric system and the CCD camera are introduced, followed by detailed analysis of their performances, and determination of the relevant parameters, including gain, readout noise, dark current and linearity of the CCD cam- era. In addition, the parameters describing the site＇s astro-climate, including typical seeing, statistics on the number of clear nights and average sky brightness, based on data gathered from Sep. 2007 to Aug. 2013, are systematically studied and reported in this work. Photometric calibrations were done using Landolt standard star obser- vations spanning eight nights, which yielded transformation coefficients, photometric precision and system throughput. The limiting magnitudes are simulated using the derived calibration parameters and classic observation conditions at WHO.

关键词： telescopes -- site testing --instrumentation: miscellaneous - tech-niques: photometric