Quantum state reconstruction of a rotational wave packet created by a nonresonant intense femtosecond laser field

We have experimentally determined the amplitudes and phases of a rotational wave packet in an adiabatically cooled benzene molecule, created by a nonresonant intense femtosecond laser field. In this wave-packet reconstruction, the initial wave packet is further interfered by a replica of the first laser pulse, and the resultant modulation in population is observed in a state-resolved manner. Though several states with different nuclear-spin modifications are populated in the initial condition, a single wave packet created from one of them (with J=0) is specifically reconstructed. Phase shifts characteristic of stepwise Raman excitation beyond the perturbative regime are experimentally identified.     

A New High-Spin Level Scheme of 128I

High-spin states in the beam energies. A new and 72 γ transitions odd-odd nucleus ^128I are investigated via the ^124 Sn（^7 Li,3n）^128 I reaction at 28 and 32 Me V level scheme of 12sI is established up to high-spin states at I^π = 16, including 48 levels The present level scheme is largely different from the one in a recent publication due to identification of several doublet and triplet γ transitions and their proper placements in the level scheme. The high-spin level structure exhibits no obvious collective properties and is possibly associated with two and multi-quasiparticle configurations.     

135La高自旋态的实验研究

利用在束γ谱实验技术,通过¹²⁸Te(¹⁰B,3n)¹³⁵La反应研究了¹³⁵La的高自旋态.基于γγ符合关系、γ射线的相对强度和各向异性度的测量结果,建立了¹³⁵La的能级纲图.在hω≈0.40MeV附近,观测到基于πh_11/2质子轨道上的负宇称带的带交叉.比较N=78同中子素链能级结构的系统性,认为该带交叉是由一对h_11/2准质子发生转动顺排造成的.在高自旋态处,观测到具有很强M1跃迁、Signature劈裂很小的ΔI=1负宇称带,根据系统性认为该带是建立在πh_11/2(νh_11/2)²组态上的γ≈–60°的扁椭球形变带.     

Positron annihilation studies of defects in 3CSiC hot-implanted with nitrogen and aluminum ions

2 ⁺ and Al⁺ at temperatures from room temperature (RT) to 1200 °C at doses of 10¹³ and 10¹⁵/cm². It is found from Doppler broadening spectra of annihilation gamma-rays obtained by varying the incident positron energy that hot-implantation gives rise to clustering of vacancies, whereas it suppresses amorphization and diminishes the thickness of damaged layers. The average size of such clusters increases with increasing implantation dose and temperature. Vacancy clustering by hot-implantation can be interpreted by the combination of vacancies during implantation. Vacancy type defects in the low-dose (10¹³/cm²) implanted samples are found to be removed by annealing at 1400 °C, whereas large vacancy clusters still remain after 1400 °C annealing in the high-dose (1 0¹⁵/cm²) implanted samples. It is also derived from the depth profile of positron diffusion length that positron scattering centers are produced after annealing at 1400 °C in all implanted samples. Received: 7 March 1997/Accepted: 6 May 1997     

Experimental evidence of a zonal magnetic field in a toroidal plasma

A zonal magnetic field is found in a toroidal plasma. The magnetic field has a symmetric bandlike structure, which is uniform in the toroidal and poloidal directions and varies radially with a finite wavelength of mesoscale, which is analogous to zonal flows. A time-dependent bicoherence analysis reveals that the magnetic field should be generated by the background plasma turbulence. The discovery is classified as a new kind of phenomenon of structured magnetic field generation, giving insight into phenomena such as dipole field generation in rotational planets.     

Polarized target asymmetry in π+ photoproduction between 0.3 and 1.0 GeV at 130°

The polarized target asymmetry for γ + p → π⁺ + n was measured at c.m. angles around 130° for the energy range between 0.3 and 1.0 GeV. A magnetic spectrometer system was used to detect π⁺ mesons from the polarized butanol target. The data show two prominent positive peaks at 0.4 and 0.8 GeV and a deep minimum at 0.6 GeV. These features are well reproduced by the phenomenological analysis made by us.     

Microscopic hydration of the sodium chloride ion pair

Hydration of ion pairs is an essential process in various physicochemical phenomena occurring in solutions. Isolated clusters of an ion pair solvated with finite number of waters have been considered as a model system for the critical evaluation of microscopic interactions involved in the process, and theoretical studies have contributed exclusively to the subject up to now. Here we report the first experimental characterization of structure and internal dynamics of hydrated ion pairs, NaCl-(H2O)n (n = 1-3). The measurements of their rotational spectra have proven that the clusters have cyclic forms, in which Na+ and Cl- ions are strongly interacted with the O and H atoms of the solvent molecules, respectively. The Na-Cl distance shows a pronounced increase with the successive addition of water molecules. The separation for n = 3 approaches the value predicted for the contact ion-pair state in aqueous solution by recent molecular dynamics simulations.     

Proposed model for the flagellar rotary motor

Flagellated bacteria swim by rotating helical filaments driven by motors embedded in the cell wall and cytoplasmic membrane. A model is proposed to explain the mechanism of the motor. The protons passing through the channels induce a strong electric field in Mot molecules. This field originates an impulse force to cause the flagellar rotation if the following conditions are fulfilled: (a) Mot molecules have a spontaneous electric polarization. (b) The lipid bilayers are viscoelastic. (c) There is a delay of deformation in response to stress in Mot molecules. The conclusions driven from the model are in agreement with the following experimental observations, denoting the flagellar rotation velocity as omega. (1) The torque is practically constant independent of omega from 0 to a critical value omega(cr) and then decreases sharply. (2) When omega is smaller than omega(cr), the torque varies little with temperature. (3) The critical velocity omega(cr) shifts to lower speed at lower temperatures. (4) Where omega is larger than omega(cr), declining of the torque steepens at lower temperatures. (5) When omega is smaller than omega(cr), one revolution of the flagellar rotation consists of a constant number of steps. (6) When omega is smaller than omega(cr), omega is proportional to the transmembrane potential difference. (7) The stator produces constant torque even when the stator is rotated relative to the rotor by external forces. (8) How the flagellar rotation velocity changes when the direction of the proton passage is reversed. (9) The motor has a switch that reverses the sense of the flagelllar rotation with the same absolute value of torque.