Medium effect of nucleon-nucleon cross section on the isoscaling parameter alpha

The medium effect of in-medium nucleon-nucleon cross section sigma(med)(NN) (alpha(m)) on the isoscaling parameter a is investigated for two couples of central nuclear reactions Ca-40 + Ca-48 and Ca-60 + Ca-48; Sn-112 + Sn-112 and Sn-124 + Sn-124 at beam energy region from 40 to 60 MeV/nucleon with isospin dependent quantum molecular dynamics. It is found that there is the obvious medium effect of sigma(med)(NN) (alpha(m)) on the isoscaling parameters alpha. The mechanism for the medium effect of sigma(med)(NN) (alpha(m)) on a is investigated.

Properties of alpha-decay to ground and excited states of heavy nuclei

Branching ratios and half-lives of alpha-decay to the ground-state rotational bands as well as the high-lying excited states of even-even nuclei have been calculated in the framework of the generalized liquid drop model (GLDM) and Royer's formula that we improved very recently. The calculation covers the isotopic chains from Ra to No in the mass regions 222 <= A <= 252 and 88 <= Z <= 102. The agreement between the calculated results and the experimental data indicates the reliability of investigating the properties of the unfavored alpha-decay with our method, especially the improved Royer's formula, which is very valuable for the analysis of experimental data. In addition, the dependence of half-lives on excitation energies of daughter nuclei has been investigated. It is shown that the influence on half-lives becomes stronger and stronger with the increase of the excitation energies.

Fine structure of alpha decay to rotational states of heavy nuclei

To gain a better insight into alpha-decay fine structure, we calculate the relative intensities of alpha decay to 2(+) and 4(+) rotational states in the framework of the generalized liquid drop model (GLDM) and improved Royer's formula. The calculated relative intensities of a decay to 2(+) states are in good agreement with the experimental data. For the relative intensities of alpha decay to 4(+) states, a good agreement with experimental data is achieved for Th and U isotopes. The formula we obtain is useful for the analysis of experimental data of alpha-decay fine structure. In addition, some predicted relative intensities which are still not measured are provided for future experiments.

alpha-decay half-lives and Q(alpha) values of superheavy nuclei

The alpha-decay half-lives of recently synthesized superheavy nuclei (SHN) are investigated by employing a unified fission model (UFM) where a new method to calculate the assault frequency of alpha emission is used. The excellent agreement with the experimental data indicates the UFM is a useful tool to investigate these alpha decays. It is found that the alpha-decay half-lives become more and more insensitive to the Q(alpha) values as the atomic number increases on the whole, which is favorable for us to predict the half-lives of SHN. In addition, a formula is proposed to compute the Q(alpha) values for the nuclei with Z >= 92 and N >= 140 with a good accuracy, according to which the long-lived SHN should be neutron rich. Several weeks ago, two isotopes of a new element with atomic number Z = 117 were synthesized and their alpha-decay chains have been observed. The Q(alpha) formula is found to work well for these nuclei, confirming its predictive power. The experimental half-lives are well reproduced by employing the UFM with the experimental Q(alpha) values. This fact that the experimental half-lives are compatible with experimental Q(alpha) values supports the synthesis of a new element 117 and the experimental measurements to a certain extent.

Measurement of the inelastic branch of the stellar O-14(alpha,p)F-17 reaction occurring in the explosive burning in Novae and X-ray busters

The inelastic component of the key astrophysical resonance (1(-), E-x=6.15 MeV) in the O-14(alpha,p)F-17 reaction has been studied by using the resonant scattering of F-17+p. The experiment was done at REX-ISOLDE CERN with the Miniball setup. The thick target method in inverse kinematics was utilized in the present experiment where a 44.2 MeV F-17 beam bombarded a similar to 40 mu m thick (CH2)(n) target. The inelastic scattering protons in coincidence with the de-excited 495 keV gamma rays have been clearly seen and they are from the inelastic branch to the first excited state in F-17 following decay of the 1(-) resonance in Ne-18. Some preliminary results are reported.

Alpha-decay for heavy nuclei in the ground and isomeric states

The alpha-decay half-lives of nuclei in the ground states and Isomeric states have been calculated within the WKB approximation and Royer's formulas. The barrier in the quasimolecular shape path is determined within a generalized liquid drop model (GLDM). in which the centrifugal potential energy has been introduced to study the unfavored a-decay The agreement between the calculated results and experimental data indicates the reliability of studying alpha-decay of isomeric states with the generalized liquid drop model We find that their is no significant difference of preformation probability between Isomeric states and the corresponding ground states generally in favored alpha-decay Additionally. we extended Royer's formulas by taking account of the role of centrifugal harrier to study the unfavored alpha-decay, and some predicts oil the a decay half-lives of Isomers are made Finally. the effects of angular momontum transfer and Q(alpha) on alpha-decay half-life have been discussed Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved

Improvement of a Fission-Like Model for Nuclear alpha Decay

The alpha decay constant is the product of the penetrability P and assault frequency nu(0) in the fission-like model. An effective assault frequency P-nu replacing the previous assault frequency nu(0) is introduced for improvement of a fission-like model named the generalized liquid drop model (GLDM) to describe the nuclear alpha decay process more accurately. Two analytical formulae are proposed for the effective assault frequency due to experimental data within the GLDM. The improved model can be used to give accurate calculations for alpha decay half-lives.

PROPERTIES OF ALPHA DECAY TO ROTATIONAL BANDS OF HEAVY NUCLEI

In the framework of the generalized liquid drop model (GLDM) and improved Royer's formula, we investigate the branching ratios and half-lives of alpha-decay to the members of the ground-state rotational bands of heavy even-even Fm and No isotopes. The calculated results are in good agreement with the available experimental data and some useful predictions are provided for future experiments.

Hydrothermal synthesis and characterization of microporous crystals of trivalent metal-containing zirconium phosphates

Two organically templated trivalent metal-containing crystalline zirconium phosphate materials FeZrPO-8 and AlZrPO-8 have been prepared hydrothermally by using fluoride as a mineralizer, and 1,6-diaminohexane (DAH) as templates. The powder XRD patterns indicate that the as-synthesized products are new materials. Substitutions of Al3+ or Fe3+ into Zr4+ sites were confirmed by a combination of powder X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) studies. The thermal behavior of the title compounds have been investigated using TG-DTA and X-ray thermodiffractometry, which indicated that the inorganic framework of the compounds are thermally stable up to similar to400 degreesC. (C) 2004 Elsevier B.V. All rights reserved.

Preparation of palladium membrane over porous stainless steel tube modified with zirconium oxide

A palladium membrane has been prepared by electroless plating on the surface of a porous stainless steel tube. Since the large surface pores of the tube are obstacle for preparation of a defect-free palladium film on the surface, zirconium oxide particles were deposited inside the pores. The mean thickness of the resulting Pd membrane on the modified tube was ca. 10 mum. It is suggested that the permeability of hydrogen is partly governed by gas diffusion in the pores. (C) 2004 Elsevier B.V. All rights reserved.

Dimerization of 1-butene via zirconium-based Ziegler-Natta catalyst

A zirconium-based Ziegler-Natta catalytic system has been tested in the dimerization of 1-butene. It was found that the concentration of Et2AlCl, Ph3P and PhONa as well as the reaction temperature had great influences on the activity and selectivity of the catalyst. Under the optimum reaction conditions, the conversion of 1-butene is 91.9%, and the selectivity of dimers is 76.7%. Basic ligands such as Ph3P and PhONa can inhibit isomerization of 1-butene to 2-butene effectively. In addition, the metal hydride mechanism was also suggested and some indirect evidence was obtained in favor of this mechanism.

树（左鼠右句）前额叶皮层神经元信息处理功能的alpha-2去甲肾上腺素能受体机制研究

本研究采用微电极胞外记录技术和微电泳技术探讨了树（左鼠右句）前额叶神经元的电生理及其alpha-2去甲肾上腺素能受体的性质发现：1.树（左鼠右句）前额叶神经元的自发放电以中频(1-10次/秒)为主。2.树（左鼠右句）前额叶存在多模和单模感觉相关神经元。3.树（左鼠右向）前额叶存在clonidine敏感神经元。4.在树（左鼠右向）前额叶多模神经元中，有较高比例的clonidine敏感神经元。本研究提示：树（左鼠右句）前额叶的clonidine敏感神经元大多为单模和多模神经元。推测这些感觉相关神经元的信息处理功能可能与alpha-2受体有关。此外，本研究表明树（左鼠右句）前额叶神经元电活动具有前额叶的特征。

Biodegradable Interpolyelectrolyte Complexes Based on Methoxy Poly(ethylene glycol)-b-poly(alpha,L-glutamic acid) and Chitosan

We synthesized methoxy poly(ethylene glycol)-b-poly(alpha,L-glutamic acid) (mPEGGA) diblock copolymer by ring-opening polymerization of N-carboxy anhydride of gamma-benzyl-L-glutamate (NCA) using amino-terminated methoxy polyethylene glycol (mPEG) as macroinitiator. Polyelectrolyte complexation between mPEGGA as neutral-block-polyanion and chitosan (CS) as polycation has been scrutinized in aqueous solution as well as in the solid state.

Ethylene polymerization by (alpha-diimine)nickel(II) complexes bearing different substituents on para-position of imines activated with MMAO

A series of (alpha-diimine)nickel(II) complexes [ArN = C(Nap)C = NAr]NiBr2 (Nap = 1,8-naphthdiyl, Ar = 2,6-Me2C6H3, 3a; Ar = 2,4,6-Me3C6H2 3b; Ar = 2,6-Me-2-4-tBuC(6)H(2), 3c; Ar 2,6-Me-2-4-BrC6H2, 3d; Ar = 2,6-Me-2-4-ClC6H2, 3e; Ar 2,6-iPr(2)C(6)H(3), 3f; Ar = 2,4,6-iPr(3)C(6)H(2), 3g; Ar = 2,6-iPr-4-BrC6H2, 3h) have been synthesized, characterized, and investigated as precatalysts for ethylene polymerization in the presence of modified methylaluminoxane (MMAO).