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Reaction mechanism of D + ND→N + D_2 and its state-to-state quantum dynamics

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Chinese Physics B 2019年第2期28卷 173-178页

作者： Ting Xu Juan Zhao Xian-Long Wang qing-tian meng School of Physics and Electronics Shandong Normal University College of Science Shandong Jiaotong University

The quantum state-to-state calculations of the D + ND→N + D_2 reaction are performed on a potential energy surface of 4 A'' state. The state-resolved integral and differential cross sections and product state distributions are calculated and discussed. It is found that the rotational distribution, rather than the vibrational distribution, of the product has an obvious inversion. Due to the fact that it is a small-impact-parameter collision, its product D_2 is mainly dominated by rebound mechanism, which can lead to backward scattering at low collision energy. As the collision energy increases, the forward scattering and sideward scattering begin to appear. In addition, the backward collision is also found to happen at high collision energy, through which we can know that both the rebound mechanism and stripping mechanism exist at high collision energy.

关键词： state-to-state quantum dynamics time-dependent wave packet D+ND differential cross section

Evaluation of semen quality in 1808 university students, from Wuhan, Central China

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Asian Journal of Andrology 2015年第1期17卷 111-116,I0010页

作者： meng Rao tian-qing meng Si-Heng Hu Huang-Tao Guan Qin-Yu Wei Wei Xia Chang-Hong Zhu Cheng-Liang Xiong Family Planning Research Institute Tongji Medical College Huazhong University of Science and Technology Wuhan Hubei 430030 China Reproductive Medicine Center Tongji Medical College Huazhong University of Science and Technology Wuhan Hubei 430030 China Hubei Province Human Sperm Bank Wuhan Hubei 430030 China Department of Epidemiology and Biostatistics School of Public Health Tongji Medical College Huazhong University of Science and Technology Wuhan Hubei 430030 China.

The aim of this study was to evaluate the semen quality of university students in Wuhan, the largest city in the world in terms of the number of university students. All student sperm donors recorded in the Hubei Province Human Sperm Bank from 1 March 2010 to 31 December 2013 were screened. At last, a total of 3616 semen samples from 1808 university student sperm donors were eligible and retrospectively analyzed. Each donor＇s semen parameters were averaged over two samples and compared with the World Health Organization criteria, and a generalized linear regression model was used to examine several determinants of semen quality. We found that the mean and median values were 3.0 ml and 2.8 ml for semen volume, 50.2 x 106 m1-1 and 50.0 x 106 m1-1 for sperm concentration, 148.1 x 106 and 142.1 x 106 for total sperm count, and 58.6% and 60.0% for total sperm motility. About 85.0% of donors had parameters that were all normal. Season and duration of abstinence were critical factors affecting semen quality. We also found a decrease in sperm concentration during the 4 years observation; however, this may not be a strong evidence to confirm the declining trend of semen quality. In conclusion, semen quality of university students in Wuhan was not optimal and should be paid high attention, long-term observation and further study should be carried out to confirm the present situation.

关键词： semen analysis semen quality sperm donors university students

Decline in semen concentration of healthy Chinese adults： evidence from 9357 participants from 2010 to 2015

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Asian Journal of Andrology 2018年第4期20卷 379-384页

作者： Hong-Fang Yuan Huang-Fang Shangguan Yi Zheng tian-qing meng Cheng-Liang Xiong Huang-Tao Guan Family Planning Research Institute Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China College of Informatics Huazhong Agricultural University Wuhan 430070 China Department of Venereology Wuhan Institute of Dermatology and Venereology Wuhan 430031 China Reproductive Medicine Center Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Hubei Province Human Sperm Bank Wuhan 430030 China

The present study aims to analyze sperm concentration trends among young and healthy Chinese adults in Wuhan, Central China, from 2010 to 2015. Semen analysis data from 9357 participants were collected and analyzed using a general linear model and the Cochran-Armitage trend test. A significant decline was observed in sperm concentration （β [standard deviation]： -1.53 [0.16]; P 〈 0.001）. In addition, a decline in sperm density was observed by stratifying student versus nonstudent sperm donors and by analyzing the year of birth or birth year cohort of the participants. Furthermore, the percentage of participants with sperm densities of over 40×10^6 ml^-1 significantly decreased with year. Notably, a dramatic decline in sperm density was recorded over the first 5 years of study.

关键词： healthy men semen concentration sperm donors temporal trends

Exact quantum dynamics study of the H(^(2)S)+SiH^(+)(X^(1)Σ^(+))reaction on a new potential energy surface of SiH_(2)^(+)(X^(2)A_(1))

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Chinese Physics B 2021年第12期30卷 399-405页

作者： Wen-Li Zhao Rui-Shan Tan Xue-Cheng Cao Feng Gao qing-tian meng School of Information Science and Engineering Shandong Agricultural UniversityTaian 271018China Department of Science Shandong Jianzhu UniversityJinan 250101China School of Physics and Electronics Shandong Normal UniversityJinan 250358China

Based on a new global potential energy surface of SiH_(2)^(+)(X^(2)A_(1)),the exact quantum dynamical calculation for the H(^(2)S)+SiH^(+)(X^(1)Σ^(+))→H_(2)+Si^(+)reaction has been carried out by using the Chebyshev wave packet *** initial state specified(νi=0,ji=0)probabilities,integral cross sections(ICS)and thermal rate constants of the title reaction are *** partial wave contributions up to J=90 are calculated in exact quantum calculation including the full Coriolis coupling(CC)*** dynamical behaviors of probabilities,ICSs and rate constants are found to be in accord with an exothermic reaction without potential *** comparing the probabilities of CC with the corresponding centrifugal sudden(CS)approximation ones,it can be concluded that neglecting CC effect will decrease the collision time,increase the amplitude of oscillation and lead to overestimation or underestimation of the reaction *** ICSs and rate constants,it is found that the deviation of CC and CS ICSs is small in the most of collision energy range except for the range of 0 eV-0.05 eV,while the deviation of both rate constants is considerable in the temperature range of 16 K-1000 K.

关键词： Chebyshev wave packet method reaction probability integral cross section rate constant

Influence factor analysis of field-free molecular orientation

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Chinese Physics B 2018年第3期27卷 231-237页

作者： Jing-Song Liu Qi-Yuan Cheng Da-Guang Yue Xu-Cong Zhou qing-tian meng School of Physics and Electronics Shandong Normal University Ji＇ nan 250358 China

The effects of the characteristics of molecules and external fields on field-free molecular orientation are investigated through the comparison of HBr with LiH driven by the combination of a two-color laser pulse and a time-delayed THz laser pulse. It is shown that the dipole interaction has greater influence on field-free orientation than the hyperpolarizability interaction. In addition to the temperature dependence of orientation degree, the effects of the amplitudes of the two-color laser pulse and THz laser pulse, rising time, and THz laser frequency on molecular orientation are also discussed.

关键词： molecular orientation external fields LiH HBr

Mechanism analysis of reaction S+(2D)+H2(X1Σg^+) → SH+(X3Σ-) + H(2S) based on the quantum state-to-state dynamics

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Chinese Physics B 2020年第6期29卷 146-152页

作者： Jin-Yu Zhang Ting Xu Zhi-Wei Ge Juan Zhao Shou-Bao Gao qing-tian meng School of Physics and Electronics Shandong Normal UniversityJinan 250358China School of Science Shandong Jiaotong UniversityJinan 250357China Shandong Provincial Key Laboratory of Biophysics Institute of BiophysicsDezhou UniversityDezhou 253023China

We present a state-to-state dynamical calculation on the reaction S++ H2→ SH+ +H based on an accurate X2 A″ potential surface. Some reaction properties, such as reaction probability, integral cross sections, product distribution, etc.,are found to be those with characteristics of an indirect reaction. The oscillating structures appearing in reaction probability versus collision energy are considered to be the consequence of the deep potential well in the reaction. The comparison of the present total integral cross sections with the previous quasi-classical trajectory results shows that the quantum effect is more important at low collision energies. In addition, the quantum number inversion in the rotational distribution of the product is regarded as the result of the heavy–light–light mass combination, which is not effective for the vibrational excitation. For the collision energies considered, the product differential cross sections of the title reaction are mainly concentrated in the forward and backward regions, which suggests that there is a long-life intermediate complex in the reaction process.

关键词： state-to-state reaction dynamics time-dependent wave packet S++H2 differential and integral cross sections

State-to-state dynamics of reactions H+DH'(v=0,j=0)→HH'(v',j')+D/HD(v',j')+H'with time-dependent quantum wave packet method

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Chinese Physics B 2021年第7期30卷 192-199页

作者： Juan Zhao Da-Guang Yue Lu-Lu Zhang Shang Gao Zhong-Bo Liu qing-tian meng School of Science Shandong Jiaotong UniversityJinan 250357China School of Physics and Electronics Shandong Normal UniversityJinan 250358China

State-to-state time-dependent quantum dynamics calculations have been carried out to study H+DH'→HH'+D/HD+H'reactions on BKMP2 *** total integral cross sections of both reactions are in good agreement with earlier theoretical and experimental results,moreover the rotational state-resolved reaction cross sections of H+DH'→HH‘+D at collision energy Ec=0.5 eV are closer to the experimental values than the ones calculated by Chao et al[***.1178341(2002)],which proves the higher precision of the quantum calculation in this *** addition,the state-to-state dynamics of H+DH'→HD'+H reaction channel have been discussed in detail,and the differences of the micro-mechanism of the two reaction channels have been revealed and analyzed clearly.

关键词： state-to-state time-dependent quantum wave-packet method differential cross sections

Dynamics of molecular alignment steered by a few-cycle terahertz laser pulse

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Chinese Physics B 2022年第10期31卷 377-383页

作者： Qi-Yuan Cheng Yu-Zhi Song Deng-Wang Li Zhi-Ping Liu qing-tian meng Medical Engineering Department Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021China School of Physics and Electronics Shandong Normal UniversityJinan 250358China Shandong Laibo Biotechnology Co. Ltd.Jinan 250101China School of Control Science and Engineering Shandong UniversityJinan 250061China

The field-free alignment of molecule Cl CN is investigated by using a terahertz few-cycle pulse(THz FCP)based on the time-dependent density matrix *** is shown that a high degree of molecular alignment can be obtained by changing the matching number of the THz FCPs in the adiabatic regime and the non-adiabatic *** matching number can affect both the maximum value of the alignment and the time at which it is *** is also found that a higher degree of alignment can be achieved by using the THz FCP at lower intensity and there exists an optimal threshold of molecular alignment with the increase of the field *** found is the frequency sensitive region in which the degree of maximum alignment can be enhanced greatly by modulating the center frequencies of different THz *** investigation demonstrates that comparing with a THz single-cycle pulse,a better result of the field-free alignment can be created by a THz FCP at a constant rotational temperature of molecule.

关键词： molecular alignment few-cycle terahertz pulse density matrix theory

Asymmetric structure of atomic above-threshold ionization spectrum in two-color elliptically polarized laser fields

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Chinese Physics B 2019年第10期28卷 183-191页

作者： Xu-Cong Zhou Shang Shi Fei Li Yu-Jun Yang Jing Chen qing-tian meng Bing-Bing Wang School of Physics and Electronics Shandong Normal UniversityJinan 250358China Laboratory of Optical Physics Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing 100190China Insititute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China Institute of Applied Physics and Computational Mathematics Beijing 100088China University of Chinese Academy of Sciences Beijing 100049China

According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are linearly polarized(LP), the spectrum shows that the multi-plateau structure is symmetric about the emitted angle of electron at π/2, while the spectrum becomes asymmetric and shifts rightwards with the increase of the EP degree of the IR laser field. Since the total ATI process is regarded as including direct ATI and the rescattering ATI, we analyze the spectrum structure of direct ATI and rescattering ATI separately. Using the saddle-point approximation, we find that for direct ATI, the fringes on the spectrum are mainly attributed to the fact that the ionization probability becomes very small when the direction of emitted electrons is perpendicular to the direction of the XUV laser polarization;while for the rescattering ATI, the interference fringes on the spectrum mainly come from the superposition of the waist structures on the spectra of all sub-channels.

关键词： above-threshold ionization elliptically polarized two color laser fields asymmetric structure