Status and perspectives of electromagnetic probes: a bright future

After a number of years of sparse results from electromagnetic probes we have seen a revitalization of this field at this conference. Exciting first results obtained by NA60 at CERN, HADES at GSI, as well as PHENIX at RHIC, cover a broad range of initial conditions created in heavy-ion collisions. These experiments hold the promise to provide accurate new data, which will certainly furnish qualitatively new insights into matter at high temperature and density. In this paper I review the status of the field today and the perspectives for the future.Arrival of the final proofs: 28 July 2005PACS: 25.75.Nq     

Infrared detection of a planet next to a bright star

Humans have always dreamt about the possibility of existence of planets in solar systems other than our own. After flying by, dropping probes, and even landing devices on most planets within our own solar system, the search for extra-solar planet is included in every proposal to either build a larger and better earth-, space-, or moon-based telescope, or observatory facility. The preliminary analysis seems to indicate that wavelength band from 25 μm to 30 μm is most promising in solving this problem. A number of IR technological challenges are to be overcome before the actual detection system can even be considered in a detailed design. The significant technical challenges of finding a planet will be described. Then details are given on the feasibility of detecting a planet with an instrument concept designed specifically for this purpose, a space-based, rotating rotationally shearing interferometer.     

Outflow refreshment angiography: A bright blood, bright static tissue technique

A new “bright blood” strategy, outflow refreshment imaging, is introduced in which a number of overlapping slices are excited in rapid succession. Flowing spins that refresh each overlapped slice portion contribute a bright signal. Additionally, static tissue in each non-overlapped slice portion also yields a bright signal. However, the flow/static contrast is comparable to that produced in inflow refreshment images, and angiograms can be generated by conventional maximum intensity projection processing. The dual ability to visualize angiograms and static tissue images is a major benefit of the strategy. Computer simulations of flow sensitivities and in vivo results are presented which compare the outflow and inflow refreshment imaging strategies.     

A bright integrated photon pair source

正The generation and detection of single photons and photon pairs are crucial to quantum information processing [1-7]. Of the various techniques, integrated photonics plays an important role. It has the advantages of mature complementary metal-oxide-semiconductor (CMOS) mass-fabrication, miniaturization, scalability, stability and reconfigurability, thus     

A road to stable dispersions: polymer-particle interactions

Dispersion stability is an essential requirement for an ideal binder for new magnetic media formulations. In this paper, an attempt is made to establish a dispersion model to enhance the degree of dispersion and its stability through the use of polymer-particle interactions. Dispersion properties have been enhanced by incorporating various functional groups in the polymer chain, and polymer design has been optimized using a statistical model of ideal polymer compositions and properties. Applications of these results are discussed.     

亮孤子微扰论的一种直接方法

发展了一种基于分离变量法的非线性Schordinger方程的微扰论直接法。导出了微扰对亮孤子的一阶效应,即导出了孤子参数随时间的缓慢变化及微扰对孤子的一阶修正     

Validation of a complex urban noise model close to a road

The adequacy of a model for the sound level close to a road is investigated by comparing resulting predictions for the sound level over a building façade with measurements. The road model involves the road geometry (the number and positions of traffic lanes), the traffic structure (vehicle flow rates and their average speeds in each lane) and equivalent omnidirectional point sources representing the vehicles. It is found that the assumed road traffic noise source model is adequate only for predicting levels over the higher part of the façade. However the investigation has allowed definition of what improvements are needed in the road source modelling to enable adequate predictions over the whole of the building façade.     

Dynamics of bright soliton bound states in (2+1)-dimensional multicomponent long wave-short wave system

In this paper, we construct the bright-soliton bound states of an integrable (2 + 1)-dimensional multicomponent long wave-short wave resonance interaction (LSRI) system by using the exact bright-soliton solutions obtained in Ref. [24] and analyze their interesting collision dynamics. We show that the beating and breathing oscillations of the bound solitons can be controlled by tuning the polarization parameters. Also, we explore the interaction between the bound-soliton and a standard soliton. We also point out that the two bound-soliton state seems to be robust against collision with a standard soliton and remain to be bounded even after collision.     

Snake instability of a spatiotemporal bright soliton stripe

We study experimentally the snake instability of the bright soliton stripe of the (2+1)-dimensional hyperbolic nonlinear Schr?dinger equation. The instability is observed, through spectral measurements, on spatially extended femtosecond pulses propagating in a normally dispersive self-defocusing semiconductor planar waveguide.     

Moving bright solitons in a pseudo-spin polarization Bose-Einstein condensate

We study the moving bright solitons in the weak attractive Bose–Einstein condensate with a spin–orbit interaction. By solving the coupled nonlinear Schr ?dinger equation with the variational method and the imaginary time evolution method,two kinds of solitons(plane wave soliton and stripe solitons) are found in different parameter regions. It is shown that the soliton speed dominates its structure. The detuning between the Raman beam and energy states of the atoms decides the spin polarization strength of the system. The soliton dynamics is also studied for various moving speed and we find that the shape of individual components can be kept when the speed of soliton is low.     

The road to gravitational-wave astronomy

Gravitational-wave astronomy is an area of great promise, yet to be realized. While we are waiting for the first (undisputed!) direct detection of these elusive waves it is useful to take stock and consider the challenges that need to be met if we want this field to reach its full potential. This write-up provides a brief introduction to some of the key ideas and the current state-of-play, and lists a range of modelling questions that need to be considered in the future.     

A novel approach to the acoustic characterisation of porous road surfaces

Porous road surfaces offer an effective means of reducing the generation and propagation of noise from road traffic. However, the porosity of these surfaces can deteriorate over time, leading to a reduction in their noise reducing properties. Efficient methods are therefore required for monitoring this performance. Existing techniques for performing in-situ measurements of acoustic absorption are unsuitable for use within the traffic stream. Static measurements using time domain Maximum Length Sequence (MLS) based techniques have been demonstrated to offer advantages over traditional techniques, presenting the opportunity for measurements under dynamic conditions. This paper describes the design of a system for carrying out dynamic MLS-based measurements. Results are presented which demonstrate that stable dynamic measurements can be carried out at speeds of up to 30 km/h.     

给牛顿力学戴上相对论协变的光环,弊大于利

指出本刊一篇文章基本思路的不妥之处，简明扼要地阐明了牛顿力学和相对论力学的分界。     

Dynamically stabilized bright solitons in a two-dimensional bose-einstein condensate

We demonstrate that a matter-wave bright soliton can be stabilized in 2D free space by causing the strength of interactions to oscillate rapidly between repulsive and attractive by using, e.g., Feshbach resonance.     

A categorization method applied to the study of urban road traffic noise

The present work summarizes a study of the hypothesis that urban noise can be stratified by measuring street noise according to a prior classification of a town's streets according to their use in communicating the different zones of the town. The method was applied to five medium-sized Spanish towns (Vitoria-Gasteiz, Salamanca, Badajoz, Cáceres, and Mérida) with populations ranging from 218 000 down to 50000 and with different socio-economic characteristics, climate, etc. As the initial hypothesis of the work was that traffic is the main source of urban noise and is also the principal cause of the variability of the sound levels measured in urban settings, the study focused only on the five nonpedestrian categories of streets. The continuous equivalent sound level (Leq) was employed in the statistical analysis as it is commonly used as a general noise index, and other noise indicators such as L(DN) or L(DEN) are calculated from it. It was found that, although differences between the medians were not statistically significant in some of the towns for certain pairs of adjacent categories, the differences between pairs of nonadjacent categories were always significant, indicative of the stratification of noise in these five towns. Further studies on other medium-sized towns and on large towns and small villages would be needed to test whether the present definition of street categories is extensible elsewhere without modification.