Spin Physics at ANKE-COSY

The COSY accelerator (Jülich, Germany) provides beams of polarised protons and deuterons. The ANKE facility at COSY is equipped with polarised hydrogen and deuterium atomic gas targets. The reactions investigated with polarised probes at ANKE include the deuteron break-up at small and large momentum transfer, the pion production processes in pp and pn collisions and the near-threshold η meson production in dip $\vec dp \to ^3 He\eta$ process. Use of the polarised deuteron beam properties allowed a precision measurement of the η meson mass. The future experimental program covers the study of the elementary pp and pn-interaction with polarised beams up to the maximal COSY energy, and a double polarised measurement of the A _{x, z} spin correlation parameter in the pN → {pp} _s π process.     

Spin Physics and the Theory of Strong Interactions

Taking the Minkowski space as the scene of quantum field theory implies an implicit assumption: the spin plays no dynamical role. This assumption (already challenged by reggeism) should be re-examined in the light of recent advances of experimental spin physics. To make a dynamical role of spin possible, it is proposed to use as a scene for the theory of strong interactions the whole Poincaré group. On the other hand characteristic functions, defined on the Poincare group, provide the only known way to describe the distinctive peculiarity of resonances, namely that a resonance is both one particle and several particles. Regge trajectories are interpreted as evidence for a mass-spin correlation among the virtual hadrons of vacuum. It is conjectured that the form of this correlation is deducible from a central limit theorem on the Poincare group. And that a statistical mechanics of hadronic vacuum is important for strong interaction theory.     

Spin Physics of Excitons in Colloidal Nanocrystals

We present a review of spin-dependent properties of excitons in semiconductor colloidal nanocrystals. The photoluminescences (PL) properties of neutral and charged excitons (trions) are compared. The mechanisms and the polarization of radiative recombination of a “dark” (spin-forbidden) exciton that determines the low-temperature PL of colloidal nanocrystals are discussed in detail. The radiative recombination of a dark exciton becomes possible as a result of simultaneous flips of the surface spin and electron spin in a dark exciton that leads to admixture of bright exciton states. This recombination mechanism is effective in the case of a disordered state of the spin system and is suppressed if the polaron ferromagnetic state forms. The conditions and various mechanisms of formation of the spin polaron state and possibilities of its experimental detection are discussed. The experimental and theoretical studies of magnetic field-induced circular polarization of PL in ensembles of colloidal nanocrystals are reviewed.     

物理和化学知识的融合

随着中小学课程改革的不断深入,学科间的联系必然加强,学科综合是大势所趋.综合试题常常渗透各种知识.所以解题时不能单独运用一门学科知识去分析、去推理,而是采用学科间相互渗透、相互交叉、相互融合的方法去培养学生的综合思维能力.本文介绍物理和化学知识融合的例题.     

关于在HIAF-BRing上开展自旋物理研究的提议(英文)

国家重大科技基础设施"强流重离子加速器装置"（High Intensity heavy-ion Accelerator Facility,HIAF）已由国家发改委批准立项并开始建设。建成之后,HIAF将为微观物质结构和重离子应用等研究提供很好的实验平台。HIAF的加速储存环（Booster Ring,BRing）设计可以加速最高动量为11.9 GeV/c的高流强质子束流。因此,HIAF-BRing将为GeV能区的核物理和强子物理研究带来新的机遇。另一方面,极化实验是研究微观物质及其相互作用的有力工具。我们提议启动相关物理和极化技术的预研工作,为在HIAF-BRing上开展自旋物理研究打下基础。The construction of the future scientific facility High Intensity heavy-ion Accelerator Facility (HIAF) in China has started. Once established, HIAF will provide excellent conditions for fundamental investigations on both matter structure and heavy-ion applications. The booster ring (BRing) of HIAF is designed to accelerate high-intensity protons with the maximum momentum of 11.9 GeV/c. Therefore it will bring new opportunities for the nuclear and hadron physics in the GeV region. Polarized experiments have been proved as a powerful tool in the explorations of the building blocks of matter. We propose to initiate a pre-investigation for the related physics and polarization techniques, which will lay the foundation of the spin physics at the HIAF-BRing.     

Spin Axioms in Different Geometries of Relativistic Continuum Physics

The 24 components of the relativistic spin tensor consist of 3 + 3 basic spin fields and 9 + 9 constitutive fields. Empirically only three basic spin fields and nine constitutive fields are known. This empirem can be expressed by two spin axioms, one of them denying purely relativistic spin fields, and the other one relating the three additional basic fields and the nine additional constitutive fields to the known (and measurable) ones. This identification by the spin axioms is material-independent and does not mix basic spin fields with constitutive properties. The approaches to the Weyssenhoff fluid and the Dirac-electron fluid found in literature are discussed with regard to these spin axioms. The conjecture is formulated, that another reduction from six to three basic spin fields which does not obey the spin axioms introduces special material properties by not allowed mixing of constitutive and basic fields.     

All-Fiber Waveguide Components: Physics, Technology, and Modelling

In this tutorial physics, technology, and modeling of three base technologies for realizing various branching components for a DWDM optical network would be presented.     

隐形技术和物理

1引言 隐形技术是第二次世界大战后出现的重大技术项目之一.特别是70年代以来,美、英等西方大国及前苏联都投入了大量的人力、物力和财力研究隐形技术,并取得了突破性进展,已由基础理论研究阶段进入实用阶段.目前,隐形技术已被应用于研制隐形飞机、隐形导弹等各种隐形武器设备,有的已研究成功并投入使用.例如,美国的洛克希德公司研制的F-117A隐形战斗机,1981年首次试飞成功,并在海湾战争和科索沃危机中投入使用.可以预见,21世纪初的战场上,将会出现大量的各种隐形武器装备,并在战争中起到举足轻重的作用.     

Spin q , Twistor and Spin c

Spin ^q structures induce (Spin ^q style) twistor spaces, which possess canonical Spin ^c structures. Such structures produce Dirac operators. Their indices for the even dimensional case, and the adiabatic limit of their reduced η-invariants for the odd dimensional case, are discussed. Received: 3 October 1995 / Accepted: 2 March 1997     

Physics and Its Interfaces with Medicinal Chemistry and Drug Design

Medicinal chemistry is a multidisciplinary subject that integrates knowledge from a variety of fields of science, including, but not limited to, chemistry, biology, and physics. The area of drug design involves the cooperative work of scientists with a diverse range of backgrounds and technical skills, trying to tackle complex problems using an integration of approaches and methods. One important contribution to this field comes from physics through studies that attempt to identify and quantify the molecular interactions between small molecules (drugs) and biological targets (receptors), such as the forces that govern the interactions, the thermodynamics of the drug–receptor interactions, and so on. In this context, the interfaces of physics, medicinal chemistry, and drug design are of vital importance for the development of drugs that not only have the right chemistry but also the right intermolecular properties to interact at the macromolecular level, providing useful information about the principles and molecular mechanisms underlying the therapeutic action of drugs. This article highlights some of the most important connections between physics and medicinal chemistry in the design of new drugs.     

Fiber Optics: Physics and Technology,by Fedor Mitschke

This Conference, under the auspices of OEEC and the International Union of Pure and Applied Physics, was attended by more than a hundred delegates, representing some twenty-six nations. The Conference Chairman was Professor Sanborn C. Brown (U.S.A.), and the Conference Secretary Mr. Norman Clarke. The forty papers to be discused had been circulated to delegates well before the Conference, and the actual sessions were devoted to general discussions based on groups of papers which formed a unifying theme. Immediately after the close of the Conference, Prof. Brown and Mr. Clarke began the preparation of a full report of the proceedings, which will make a substantial volume. Among the general topics discussed were the place of physics in general education (opened by Mr. Clarke); the selection of university entrants for physics courses (Prof. G. K. T. Conn); examinations in physics (Dr. H. F. Boulind); the use of films and television in physics teaching (Dr. Harvey White, U.S.A.); and the Physical Science Study Committee's syllabus and programme (Prof. J. R. Zacharias, U.S.A.).