A Rule to Design High Spin Molecules with Hetero spin Centers

The series of biradicals with m phenylene coupling unit and hetero spin centers were calculated compared with those possessing homo spin centers using AM1 CI method. A simple rule was proposed to design high spin molecules with ferromagnetic coupling unit and hetero spin centers. Two neutral (or charged) hetero spin centers resulted in high spin ground state, one neutral and another charged hetero spin centers correspond to low spin ground state. The latter was ascribed to the huge splitting of two partially occupied molecular orbitals.

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.

Method of measuring rotation speed of high spinning projectile based on plane magnetic induction coil

For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.

Shell Model Investigation of High Spin States for Ce Isotopes

-A truncated shell model approach is presented for studying the properties oflow-lying states as well as the high-spin states in even-even nuclei with the help of thegeneralized boson-fermion expansion technique.The primary fermion state space isspanned by the interacting valence protons and neutrons with effective nucleon-nucleonforce.The truncated model space is considered as a direct sum of two subspaces corre-sponding to the configurations of（sd）N and（sd）N-1,respectively,plus a broken fermionpair.Numerical calculations are carried out for 130～134Ce isotopes.The calculated spec-trum reproduces the experimental data quite well,especially the backbending appearingin these nuclei.The results suggest that the approach is able to describe the spectroscopyof states with angular momenta up to J≈20.

High spin states in stable nucleus ^(84)Sr

High spin states of 84Sr were populated through the reaction 70Zn(18O,4n)84Sr at 75 MeV beam energy.Measurement of excitation function,γ-γ coincidences,directional correlation from oriented state (DCO) ratios and γ-transition intensities were performed using eight anticompton HPGe detectors and one planar HPGe detector.Based on the measured results,a new level scheme of 84Sr was established in which 12 new states and nearly 30 new γ-transitions were identified in the present work.The positive-parity states of the new level scheme were compared with the results from calculations in the framework of the projected shell model (PSM).One negative-parity band was extended to spin Iπ=19-and it can be found that in the high spin states,the γ-transition energies show the nature of signature staggering.The negative-parity band levels are in good agreement with deformed configuration-mixing shell model (DCM) calculations.

Structure of high spin state in proton-rich ^(74,76,78)Kr isotopes:A projected shell model description

The N≈Z nuclei in the mass A^80 region has been researched because of an abundance of nuclear structure phenomena.The projected shell model(PSM)was adopted to investigate the structure of high spin state in proton-rich 74,76,78Kr isotopes including yrast spectra,moment of inertia,electric quadrupole transitions and the behavior of single particle.The calculated results are in good agreement with available data and the shape coexistence in low-spin is also discussed.

Evidence for coexisting prolate and near-oblate shapes at high spin in 125Cs

Excited states in the odd-proton nucleus 125Cs were investigated by means of in-beam β-ray spectroscopy. The πg7/2 band is observed to fork into a △I = 1 coupled band and a △I = 2 decoupled band at high spins. To assign the possible configurations of these two bands, experimental B（M1）/B（E2） ratios and signature splittings have been evaluated for the △I = 1 band, and calculations based on the geometrical model, cranked shell model and total Routhian surfaces model have been performed. They are suggested to be a near-oblate band built on the （πg7/2/d5/2） （vh11/2）2 configuration and a prolate band built on the πg7/2 （πh11/2）2 configuration, respectively.

High-Spin States in ^(141)Pm

The high-spin states of 141pro nucleus have been studied by using in-beam v-ray spectroscopy technology through the126Te（19F, 4n） reaction at a beam energy of 90 MeV. The previous level scheme has been extended with spin up to 49/2 h. Many new levels and transitions are identified. Five collective band structures are observed. Based on systematic comparison with the neighboring nuclei, two bands with strong AI = 1 M1 transitions inside the bands are proposed as the oblate bands with γ--60°, and three bands with large signature splitting have been suggested as the oblate-triaxial deformation with γ--90°. The characteristics for these bands have been discussed.

New high spin level scheme of ^(87)Sr

High spin states of the odd-A STSr were populated by the fusion-evaporation reaction ^82Se（^9Be,4n） u. br at a beam energy of 46 MeV. Excited levels of SrSr have been extended up to an excitation energy of 7.4 MeV at spin 31/2h. The coupling of a g9/2 neutron hole to the yrast states of the SSSr core can account for the low-lying states in STSr. The structure of the higher spin states is discussed by analogy with those of the neighboring odd-A N=49 isotones and possible configurations are proposed.

High spin states in ^(71)Ga

Excited states in the odd-A nucleus 71Ga have been studied via the ^(70)Zn(7Li,a2n)^(71)Ga fusion-evaporation reaction with incident beam energies of 30 and 35 MeV.The level scheme is established up to spin I^(n)=(29/2^(+))and an excitation energy-6.6 MeV.A previously known sequence built on the 9/2^(+) state is extended as a novel rotational band originating from the v(8^(2)_(9/2)alignment.Furthermore,a negative-parity sequence Is also reported.The observed energy levels of Ga have been interpreted in the framework of the nuclear shell model(SM).

Theoretical Design of High-spin Organic Molecules with Heterocycles as Ferromagnetic Coupling Units

Novel stable high spin molecules possessing three different arranged fashions are designed with - · N-N< as a spin-containing(SC) fragment, phenylene as an end group and various aromatic molecules, such as benzene(1), 2,6-pyridine(2), 3,5-pyridine(3), pyridazine(4), 4,6-pyrimidine(5), 2,6-pyrimidine(6), pyrazine(7) and triazine(8), as a ferromagnetic coupling(FC) unit. The effects of the different coupling units on the spin multiplicities of the ground states and their stabilities were investigated by means of AM1-CI approach. It has been found that the spin densities on the two atoms of the SC fragment are different from delocalization results in the specific stability of - · N-N<. In these molecules, the stabilities of the triplet states decrease when the distance between the atoms of central SC(-N-) increases. It is shown that the heterocycles as the coupling units have influence on the stabilities of the high-spin ground states. That the heteroatom lying in m -phenyl can improve ferromagnetic coupling, while the heteroatom lying in o -phenyl or p -phenyl is not in favor of the ferromagnetic coupling.

Theoretical Design of High-spin Organic Molecules with —~*N—S— as a Spin-containing Fragment and Heterocycle as End Groups

Novel stable high-spin molecules possessing three different arranging fashions were designed with —^＊N—S— as a spin-containing （SC） fragment, an aromatic group, such as benzene （ 1 ）, pyridine （2）, pyridazine （3） , pyrimidine （4）, pyrazine （5） or triazine （6） as end groups （EG）, and phenyl as a ferromagnetic coupling （FC） unit. The effects of different EG on the spin multiplicities of the ground states and their stabilities were investigated by means of the AM1-CI approach. All the investigated molecules corresponded to the FC and possessed high-spin ground states. The spin on the two atoms of the SC fragment was not in agreement with the delocalization results in the specific stability of —^＊N—S—. In those molecules, the stabilities of the triplet states decreased when the distance between the atoms of central SC fragments （—N—） increased. The stabilities of the triplet states of compounds 1a-n, 1b-n and 1c-n, with heterocycles as EG were higher than those of the triplet states of those compounds with phenyl as EG. Furthermore, the stahilities of the triplet states of the compounds with pyrimidine and triazine as EG were higher than those with pyridine, pyridazine or pyrasine as EG.

Reinvestigation of the high spin states in ^(161)Er and enhanced E1 transitions in the N=93 isotones

High-spin states in 161Er have been studied experimentally using the 150Nd（16O, 5n） reaction at a beam energy of 86 MeV. The relatively enhanced E1 transitions between the 5/2＋[642] and 3/2-[521] bands are observed in 161Er, and the B（E1） values are extracted experimentally. The systematics of the R（E1） values in the N = 93 isotones are presented. It is found that the strength of the E1 transitions obviously exhibits angular momentum dependence, and the occurrence of the relatively enhanced E1 transitions could be attributed to octupole softness.

High spin band structure in ^(139)Nd

High-spin states in 139Nd nucleus have been reinvestigated with the reaction 128Te (16O, 5n) at a beam energy of 90 MeV. The level scheme has been expanded with spin up to 47/2 . At the low spin states, the yrast collective structure built on the νh11/2-1 multiplet shows a transitional shape with γ ≈ 32° according to calculations of the triaxial rotor-plus-particle model. Three collective oblate bands with γ ～-60° at the high spin states were identified for the first time. A band crossing is observed around ω ～0.4 MeV in one oblate band based on the 25/2-level.

Necking Point in PET High-speed Fiber Spinning

Cross-over method is established to predict necking point for PET high- speed fiber spinning. Even slowly crystallizing polymers such as PET can crystallize on the spinline at sufficiently high spinning speed. The development of rtmning velocity, temperature, crystallinity and theological force is investigated for the take-up velocity over a range of 6 000 - 10 000 m/min. The position of necking point, temperature rise and abrupt increase of crystallinity move closer to the spinneret with the increase of take-up velocity,

STRUCTURE EVOLUTION OF POLYMER CHAINS FOR NECKING FORMATION IN HIGH-SPEED FIBER SPINNING PROCESS

Finite element method is used to simulate the high-speed melt spinning process, based on the equation system proposed by Doufas et al. Calculation predicts a neck-like deformation, as well as the related profiles of velocity, diameter, temperature, chain orientation, and crystallinity in the fiber spinning process. Considering combined effects on the process such as flow-induced crystallization, viscoelasticity, filament cooling, air drag, inertia, surface tension and gravity, the simulated material flow behaviors are consistent with those observed for semi-crystalline polymers under various spinning conditions, The structure change of polymer coils in the necking region described by the evolution of conformation tensor is also investigated. Based on the relaxation mechanism of macromolecules in flow field different types of morphology change of polymer chains before and in the neck are proposed, giving a complete prospect of structure evolution and crystallization of semi-crystalline polymer in the high speed fiber spinning process.

A Microscopic Investigation of High-Spin States for ^(162)Hf and ^(164)Hf Isotopes

A truncated shell model approach is applied to the description of high-spinstates for 162Hf and 164Hf isotopes.The backbends of the moment of inertia are repro-duced well by the calculation.The results show that the approach is able to investigatethe yrast states of nuclei in rare earth region.

Optical pumping and population transfer of nuclear-spin states of caesium atoms in high magnetic fields

Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti：sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the hyperfine Zeeman sublevels, which results from the collision-induced modification δa（S·I） of the hyperfine interaction of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different buffer-gas pressures. The experimental results show that high-field optical pumping and the small change δa（S · I） of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation.

Microstructure Distribution Characteristics of High-Strength Aluminum Alloy Thin-Walled Tubes during Multi-Passes Hot Power Backward Spinning Process

The microstructure of the thin-walled tubes with high-strength aluminum alloy determines their final forming quality and performance. This type of tube can be manufactured by multi-pass hot power backward spinning process as it can eliminate casting defects, refine microstructure and improve the plasticity of the tube. To analyze the microstructure distribution characteristics of the tube during the spinning process, a 3D coupled thermo-mechanical FE model coupled with the microstructure evolution model of the process was established under the ABAQUS environment. The microstructure evolution characteristics and laws of the tube for the whole spinning process were analyzed. The results show that the dynamic recrystallization is mainly produced in the spinning deformation zone and root area of the tube. In the first pass, the dynamic recrystallization phenomenon is not obvious in the tube. With the pass increasing, the trend of dynamic recrystallization volume percentage gradually increases and extends from the outer surface of the tube to the inner surface. The fine-grained area shows the states of concentration, dispersion, and re-concentration as the pass number increases. .