Particle scattering factor of pearl necklace chains

The particle scattering behaviour of a pearl necklace chain is derived. The chain is composed of sphere-like pearls, separated by rod-like segments of fixed length, which have no angular restrictions. By calculating several series of model scattering curves, the important structural features are retrieved. The model is believed to be useful in interpreting intermediate structures of collapsing macromolecules or polyelectrolytes. A first application to a shrinking polyelectrolyte coil generated by molecular dynamic simulations (Limbach and Holm, J.Phys.Chem. 2003) is presented and used to discuss the potentials and limits of the model.     

单核子在具有八极形变的平均势场中的混沌运动(Ⅱ)初始相干态空时演化中正则变量的期望值和测不准度的特征

研究了二维不对称谐振子的相干态在附加八极形变势作用下传播时,量子正则变量的期望值和测不准度的变化,发现量子混沌与相应的经典混沌完全对应地表现了多种性质.量子混沌的特征也与势能面的几何对称性,即势能面上负曲率的存在及负曲率的大小有关系.     

大鼠臂旁核内注入去甲肾上腺素及受体阻断剂对迷走—加压反应的影响

采用药物微量注射的方法,研究了２９只大鼠臂旁核（ＰＢＮ）内微量注入去甲肾上腺素（ＮＡ）及受体阻断剂酚妥拉明和心得安对迷走—加压反应的影响．结果表明,ＰＢＮ内注入ＮＡ可显著减弱迷走—加压反应;酚妥拉明可反转由ＮＡ引起的血压反应;心得安无作用．提示,ＰＢＮ参与迷走—加压反应,对此反应的影响是通过α受体实现的     

Analysis of Neutron Double-Differential Cross Section of n+14N at 14.2 MeV

By using a new reaction model for light nuclei, the double-differential cross section of n 14N reactions at En = 14.2 MeV has been analyzed. In the case of n 14N reactions, the reaction mechanism is very complex, there are over one hundred opened partial reaction channels even at incident energy En = 14.2 MeV. In this paper the opened reaction channels are listed in detail. With LUNF code the model calculation is performed to analyze the doubledifferential cross sections of total outgoing neutron. The calculated results agree fairly with the experimental data. The results indicate that the pre-equilibrium mechanism dominates the whole reaction processes, and the recoil effect in light nuclear reactions is essentially important. 5He emission has been considered, but it is only a small contribution to the double-differential cross section at incident energy En = 14.2 MeV.     

运动疲劳大鼠丘脑腹外侧核神经元自发放电特征的分析

通过观察力竭运动对大鼠丘脑腹外侧核(VL)神经元自发放电活动的影响,探讨丘脑腹外侧核在运动疲劳中枢调控过程中的作用.选取雄性Wistar大鼠,随机分为对照组和疲劳组.采用跑台递增负荷运动方案,建立运动疲劳模型.采用玻璃微电极的体电生理学技术,观察丘脑腹外侧核神经元自发放电活动,并对其放电模式、放电频率、锋电位间隔直方图进行线下分析.得到了FG大鼠丘脑腹外侧核单簇发混合放电和规则单发放电神经元比例明显低于CG(P0.01),爆发式放电神经元比例明显高于CG(P0.01).FG大鼠丘脑腹外侧核神经元总放电频率显著低于CG(P0.05),规则单发放电频率有所升高,单簇发混合放电频率有所降低,但与CG相比均未见显著差异(P0.05).可以看出大鼠丘脑腹外侧核神经元参与了运动性疲劳的中枢调控.丘脑腹外侧核在运动疲劳引起间接通路与直接通路的调节功能失衡过程中起关键作用.     

Residue Coulomb Interaction Among Isobars and Its Influence in Symmetry Energy of Neutron-Rich Fragment

The residue Coulomb interaction (RCI), which affects the result of symmetry-energy coefficient of neutron-rich nucleus in isobaric yield ratio (IYR) method, is difficult to be determined. Four RCI approximations are investigated: (i) The M1-RCI adopting the a_c/T (the ratio of Coulomb energy coefficient to temperature) determined from the IYR of mirror-nucleus fragments; (ii) The M2-RCI by fitting the difference between IYRs; (iii) The M3-RCI adopting the standard Coulomb energy at a temperature T=2 MeV; and (iv) Neglecting the RCI among isobars. The M1-, M2- and M3-RCI are no larger than 0.4. In particular, the M2-RCI is very close to zero. The effects of RCI in a_sym/T of fragment are also studied. The M1- and M4-a_sym/T are found to be the lower and upper limitations of a_sym/T, respectively. The M2-a_sym/T overlaps the M4-a_sym/T, which indicates that the M2-RCI is negligible in the IYR method, and the RCI among the three isobars can be neglected. The relative consistent low values of M3-a_sym/T (7.5±2.5) are found in very neutron-rich isobars.     

High-spin states in neutron-rich 102Mo nucleus

High-spin states in neutron-rich 102Mo nucleus have been studied by measuring the prompt γ-rays in the spontaneous fission of 252Cf. The previous level scheme has been updated and some new levels and transitions are identified. The one-phonon γ-band is expanded and a band head level of the two-phonon γ-band is proposed. The systematic characteristics of yrast bands, one-phonon γ-bands, two-phonon γ-bands and quasi-particle bands in 102Mo, 104Mo and 106Mo are discussed.     

Gamma Vibrational Bands and Chiral Doublet Bands in A≈100 Neutron-rich Nuclei

The level structures of neutron-rich ~(105)Mo,~(106)Mo,~(108)Mo and 110Ru nuclei in A≈100 region have been carefully investigated by coincidence measurements of the prompt γ-rays populated in the spontaneous fission of ~(252)Cf with the Gammasphere detector array.In 105Mo,one-phonon K =9/2 and two-phonon K=13/2 γ-vibrational bands have been identified.In ~(108)Mo,one-phonon γ-vibrational band is expanded and two-phonon γ-vibrational band has been identified.Two similar sets of bands in ~(106)Mo and ~(110)Ru are observed to high spins,which have been proposed as the soft chiral γ-vibrational bands.The characteristics for these γ-vibrational bands and chiral doublet bands have been discussed.     

76Sr核yrast带结构演化的微观研究

对于发生在同一个原子核中的、从一种高有序激发模式向着另一种低有序激发模式演化的机理和物理图像,提出了一种新的理解：被布居到高角动量态的高有序激发核,以E₂跃迁方式先行退耦到yrast带,再退耦到共存区时释放了结构能,诱发价核子对耦合强度改变,重新组合出低有序的激发模式基准态,实现了基准态结构的过渡.从微观上看,这是一种既温和而又平稳的转变.并以⁷⁶Sr核为例作了深入阐述. 关键词： 量子相变 yrast带结构演化 微观sdIBM-2方案 76Sr核')" href="#">⁷⁶Sr核     

Structure elucidation of an unexpected product from dehydration of a beta-hydroxyketone

The structure of an unexpected compound from the dehydration of an aldol addition product has been determined using 1-D and 2-D NMR techniques. This reaction is the last step in a new synthetic approach to the galanthan ring system. Complete 1H and 13C NMR assignments for two synthetic precursors are also reported.