Description of Rotation Bands in ^(157,158)Er at Ultrahigh Spin

Properties of the four rotation bands, ^157Er（1,2） and ^15SEr（1,2）, at ultrahigh spin are investigated within the supersymmetry scheme including many-body interactions and possessing the SO（5） （or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the 7-ray energies and the dynamical moments of inertia in the rotation bands in ^157 Er and ^158 Er at ultrahigh spin are obtained. We theoretically predict that the competition between the anti-pairing and pairing effects may exist in ^157 Er（1,2） and ^158Et（2） bands states. In ^158Er（1） band state, the favourepairing effects may exist and the SO（5） （or SU（5）） symmetry play a dominant role. There may be sphere coexisting with headecupole deformed in ^158Et（1） rotation band state.

The Interacting Boson Model for Anomalous Rotational Bands

The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.

A phenomenological model for plastic flow behavior of rotating band material with a large temperature range

The plastic flow behavior of the rotating band material is investigated in this paper. The rotating band material is processed from H96 brass alloy, which is hardened to a much higher yield strength compared to the annealed one. The dynamically uniaxial compression behavior of the material is tested using the split Hopkinson pressure bar(SHPB) with temperature and strain rate ranging from 297 to 1073 K and500 to 3000 s^(-1), respectively, and a phenomenological plastic flow stress model is developed to describe the mechanical behavior of the material. The material is found to present noticeable temperature sensitivity and weak strain-rate sensitivity. The construction of the plastic flow stress model has two steps. Firstly, three univariate stress functions, taking plastic strain, plastic strain rate and temperature as independent variable, respectively, are proposed by fixing the other two variables. Then, as the three univariate functions describe the special cases of flow stress behavior under various conditions, the principle of stress compatibility is adopted to obtain the complete flow stress function. The numerical results show that the proposed plastic flow stress model is more suitable for the rotating band material than the existing well-known models.

Ground-State Bands of Fm and No Isotopes in Cluster Model

We investigate the ground-state rotational bands of nuclei with Z 〉 100 using cluster model proposed by Buck et al. [Phys. Rev. Left. 94 （2005） 202501]. The core-duster decomposition of each nucleus is determined by the corresponding electric quadrupole transition strength B（E2 ： 2^＋ → 0^＋）. The theoretical spectra of fermium and nobelium isotopes are compared with available experimental data. Good agreement between model and data is obtained.

用于冲激雷达的宽带旋转对称单极天线的分析与设计

采用扩展矩量法对两种不同形状旋转对称单极天线进行了分析研究 ,得出了最佳锥角和天线下限频率随天线高度变化的曲线 ,设计制作了一下限频率为 10 0 0 MHz的天线来验证此曲线 ,另外制作了一中心频率为75 0 MHz用于冲激雷达的旋转对称单极天线 ,均采用扩展矩量法进行了分析 ,与部分测试结果相比较 ,两者吻合较好 ,为工程设计提供了理论依据。

一种用于冲激雷达的宽带天线的分析与设计

通过采用扩展矩量法对不同形状旋转对称单极天线进行了分析研究 ,并设计制作了两种具有宽带特性中心频率 750 MHz的旋转对称单极天线。这种用于冲激雷达的宽带天线具有高增益、全向、超宽带等特点。分析中采用扩展矩量法 ,与部分测试结果相比较 ,两者吻合较好 。

General design principle of artillery for firing accuracy

In this paper,based on the topological description method,the kinematic and dynamic equations of the projectile flight and projectile-artillery coupling system during the whole process of firing are constructed.The factors that can affect the projectile burst points,namely the state parameters of the projectile on the muzzle and state parameters of the barrel muzzle,as well as the factors that affect the barrel muzzle state parameters,are analyzed.On this basis,the design principle of artillery firing accuracy is proposed.The error analysis and the corresponding inverse problem,the extraction method of key parameters affecting artillery implicated motion,the conformal and control method of rotating band are analyzed and presented.Finally,the presented method is verified through a vehicle mounted howitzer case,and the muzzle state parameter interval is obtained meeting the given firing accuracy.In addition,the sensitivity analysis of artillery parameters shows that the less the correlation between the parameters and the barrel,the less the influence on the projectile implicated motion.The analysis of the coupling effect between rifling and the rotating band shows that the uniform rifling is the optimal form for the conformal of the rotating band during firing.

Description of all observed rotational bands in ^(128)Pr

The configuration-dependent cranked Nilsson-Strutinsky approach was used to investigate the rotational structures in 128Pr and signature splittings of some observed bands could be well described quantitatively at high spin. Its modified model was used to calculate special configurations in order to distinguish the N=4 d3/2s1/2 and g7/2d5/2 orbitals. All observed bands were compared with the calculated configuration assigned to the band and the agreement between experiment and theory is remarkable.

A New Calculation of Rotational Bands in Alpha-Cluster Nuclei

One of the cluster behaviors observed in light nuclei such as20 Ne and44 Ti is the presence of an alpha particle rotating around a double magic number core. In this work, a theoretical method is used for investigation of rotational spectra of two-particle cluster states. To this end, Deng-Fan potential in addition to Hellman potential is used as the core and cluster potential. Next, given the Wildermuth condition, and proper quantum numbers describing the relative motion of the alpha particle and core, the rotational levels of20 Ne and44 Ti isotopes are calculated. Our studies show that the results are in good agreement with the available data.

Comparison between formulas of rotational band for axially symmetric deformed nuclei

The experimental rotational spectra of the deformed nuclei available in even-even and odd-A nuclei in the rare-earth and actinide regions are systematically analyzed with several rotational spectra formulas, including Bohr-Mottelson＇s I（I＋ 1）-expansion, Harris＇ ω^2-expansion, ab and abc formulas. It is shown that the simple 2-parameter ab formula is much better than the widely used 2-parameter Bohr-Mottelson＇s AB formula and Harris＇ αβ formula. The available data of the rotational spectra of both ground-state band in even-even nuclei and one-quasiparticle band in odd-A nuclei can be conveniently and rather accurately reproduced by ab formula and abc formula. The moment of inertia and the variation with rotational frequency of angular momentum can be satisfactorily reproduced by ab and abc formulas.

High-k Structures in (124)～Cs

High spin states in the odd-odd nucleus 124Cs have been investigated through the fusion-evaporation reaction 116Sn（11B, 3n）l24 Cs with a beam energy of 45 MeV. A new rotational band is established and assigned as the high-k configuration of πg9/2140419/2＋ ⊙vh 11/2[523]7/2-. Some structures linking to this band have also been observed. According to the results of the excitation energy systematics, the lowest level of this band is assigned as 9-, and the 8- isomer bandhead has not been observed. Another isomer with a half life of 6.3 s has also been observed with its new decay paths established, Its excitation energy is raised by 79 keV, but its Iπ is not changed.

High Spin Structure in ^(106)Pd

The high spin states of 106pd have been populated through the 100Mo（11B, lp4n）106Pd reaction using a beam energy of 60 MeV provided by the Beijing HI-13 tandem accel- erator at China Institute of Atomic Energy. By analyzing the V-3＇ coincidence relation and DCO raios of transitions, 3 rotational bands with 13 new states and 22 new 7 transitions belonging to 106pd were constructed. Bands 2 and 3 with negative parity were supposed to build on the vh1l/297/2 and vh11/2ds/2 configuration, respectively.

The Interacting Boson Model of Dipole—Octupole Strong Correlations in SU（3） Limit for Positive Parity States

Within the framework of the Usdpf(16) interacting boson model (IBM), the effects of strong correlations of the dipole (p?-boson) and the octupole (f?-boson) degree of freedom on the positive-parity states of even-even nuclei in SU(3) limit are discussed. It is shown that configurations of an even number of many p- and f-bosons can not only be incorporated into the usual low-lying collective rotational bands, such as the ground state band, β- and γ-vibrational bands, but also naturally form the rotational bands, etc. These results are similar to that of Usdg(15)-IBM and in good agreement with the experimental data of the nucleus. Besides, several intraband E2 transition probabilities are given, which are consistent with that of Usd(6)-IBM.

Tribology of rotating band and gun barrel during engraving process under quasi-static and dynamic loading

The engraving process of a projectile rotating band is one of the most basic research aspects in interior ballistics,which has not been thoroughly understood thus far.An understanding of this process is of great importance from the viewpoints of optimal design,manufacturing,use,and maintenance of gun and projectile.In this paper,the interaction of copper and nylon rotating bands with a CrNiMo gun barrel during engraving was studied under quasi‐static and dynamic loading conditions.The quasi‐static engraving tests were performed on a CSS‐88500 electronic universal testing machine(EUTM)and a special gas‐gun‐based test rig was designed for dynamic impact engraving of the rotating bands.The mechanical behaviors of copper and nylon were investigated under strain rates of 10^(−3) s^(−1) and 2×10^(3) s^(−1) using an MTS 810 and a split Hopkinson pressure bar(SHPB),respectively.Morphologies of the worn surfaces and cross‐sectional microstructures were observed with scanning electron microscope(SEM)and optical microscope(OM).It was found that large deformation and severe friction occur during engraving.The surface layer is condensed and correlated with a hardness gradient along the depth from the top worn surface.The structure of the rotating band and gun bore,band material,and loading rate have great effects on band engraving.The flow stress‐strain of the copper strongly depends on the applied strain rate.It is suggested that strain rate and temperature play significant roles in the deformation mechanism of rotating bands.

Rotational properties of the odd-Z transfermium nucleus ^(255)Lr by a particle-number-conserving method in the cranked shell model

Experimentally observed ground state band based on the 1/2-[521] Nilsson state and the first exited band based on the 7/2-[514] Nilsson state of the odd-Z nucleus 255Lr are studied by the cranked shell model （CSM） with the paring correlations treated by the particle-number-conserving （PNC） method. This is the first time the detailed theoretical investigations are performed on these rotational bands. Both experimental kinematic and dynamic moments of inertia （f^（1） and ,f^（2） versus rotational frequency are reproduced quite well by the PNC-CSM calculations. By comparing the theoretical kinematic moment of inertia f（1） with the experimental ones extracted from different spin assignments, the spin 17/2- →13/2- is assigned to the lowest-lying 196.6（5） keV transition of the 1/2- [521 ] band, and 15/2→11/2- to the 189（1） keV transition of the 7/2- [514] band, respectively. The proton N = 7 major shell is included in the calculations. The intruder of the high-j low→lj15/2 （1/2-[770]） orbital at the high spin leads to band-crossings at hω = 0.20 （hω~=0.25） MeV for the 7/2-[514]ω= -1/2 （ω= ＋1/2） band, and at hω=0.175 MeV for the 1/2- [521 ] ω= - 1/2 band, respectively. Further investigations show that the band-crossing frequencies are quadrupole deformation dependent.

High-K multi-particle bands and pairing reduction in 254No

The multi-particle states and rotational properties of the two-particle bands in 254No are investigated by the cranked shell model with pairing correlations treated by the particle number conserving method. The rotational bands on top of the two-particle Kπ= 3+, 8- and 10+ states and the pairing reduction are studied theoretically in 254No for the first time. The experimental excitation energies and moments of inertia of the multi-particle states are reproduced well by the calculations. Better agreement with the data is achieved by including the high-order deformation ε6,J（1） in these two-particle bands compared with the ground state band is attributed to the pairing reduction due to the Pauli blocking effect.

Rotational structure of the odd-proton nuclide ^(171)Tm:A projected shell model study

Deformed odd-mass nuclei are ideal examples where the interplay between single-particle and collective degrees of freedom can be studied. Inspired by the recent experimental high-spin data in the odd-proton nuclide 171 Tm, we perform projected shell model(PSM) calculations to investigate structure of the ground band and other bands based on isomeric states. In addi- tion to the usual quadrupole-quadrupole force in the Hamiltonian, we employ the hexadecapole-hexadecapole(HH) interac- tion, in a self-consistent way with the hexadecapole deformation of the deformed basis. It is found that the known experi- mental data can be well described by the PSM calculation. The effect of the HH force on the quasiparticle isomeric states is discussed.

Shears bands in ^(112)In

A new level scheme of 112In have been established up to 6.8 MeV in excitation energy and to a tentative spin of (21+) through the reaction 110Pd(7Li,5n)112In at a beam energy of 50 MeV. In-beam measurements involving γ-γ coincidences and directional correlation of oriented states were performed. M1 bands consisting of I =1 dipole transitions have been observed. Possible quasiparticle configurations suggest that these bands are similar to the shears bands observed in Pb nuclei.

Description of moment of inertia and the interplay between anti-pairing and pairing correlations in ^(244)Pu and ^(248)Cm

A variable moment of inertia(VMI)inspired interacting boson model(IBM),which includes many-body interactions and a perturbation possessing(5)(or(5))symmetry,is used to investigate the rotational bands of the mass region.A novel modification is introduced,extending the Arima coefficient to the third order.This study is dedicated to the quantitative analysis of evolving trends in intrabandγ-transition energy as well as the kinematic and dynamic moments of inertia(MoIs)within the rotational bands of ^(244)Pu and ^(248)Cm.The computed outcomes exhibit an exceptional degree of agreement with experimental observations across various conditions.The significance of including a higher-order Arima coefficient is further examined by contrasting it with the previously proposed model.The calculated results demonstrate the significance of both the anti-pairing and pairing effects in the evolution of the dynamic MoI.Additionally,these insights reveal the importance of a newly introduced parameter in accurately depicting complex nuclear behaviors,such as back-bending,up-bending,and downturn in the MoI.

激光诱导NO_2分子500—532nm区荧光激发谱的实验研究

用准分子激光抽运可调谐染料窄带激光测定了室温下NO2 分子 5 0 0— 5 32nm区高分辨荧光激发谱 ,在两个较强吸收区 5 0 5— 5 10nm和 5 13— 5 2 0nm范围内标识了 2 5个振动带 ,并作了转动分析 ,得到了相应的带头位置、转动常数和旋 转偶合常数等分子光谱常数 ,在 2 5个振动带中有 5个谱带是新发现的 ,所有得到转动分析的谱线均属于平行跃迁X～ 2 A1—A～2 B2 ,对实验结果的分析表明电子激发态A～ 2B2 受到基态X～ 2