Study of the reactione + e −→K + K − in the energy range1350 \leqq \sqrt s \leqq 2400 MeV

Thee ⁺ e ^?→K ⁺ K ^? cross section has been measured from about 750 events in the energy interval \(1350 \leqq \sqrt s \leqq 2400 MeV\) with the DM2 detector at DCI. TheK ^± form factor |F _F ^±| cannot be explained by the ρ, ω, ? and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment.     

Radiative decay ofJ/ψ into γ π+ π−

The radiative decayJ/ψ → γ π⁺ π^? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe ⁺e^? storage rings at Orsay. The π⁺ π^? mass spectrum shows a cleanf ₂ (1270) signal, and the possible presence of two other states at thef ₂ (1720) andf ₄ (2030) masses. For thef ₂ (1270), the branching ratio BR(J/ψ →γf)xBR(f→π⁺ π^?) is measured to be (7.50±0.30±1.12)×10^?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed.     

Non-planar smoulder propagation governed by diffusion

The steady propagation of a thin smouldering front in a half-spacehas been considered. A suitable coordinate transformation hasallowed the region near the leading edge of the front to beexamined for both a maintained planar surface and with surfacecollapse due to material shrinkage. The change in the oxidizerconcentration for a small increment in the propagation speedfor large time and surface collapse has been determined. Theinfluence of two types of nonlinear diffusion on the shape ofthe smouldering front has been found; other cases can be dealtwith in a similar manner.     

Methods and techniques for the selective extraction and recovery of oxoanions

An important goal in environmental chemistry is the extraction of metals that are toxic or radioactive from soils and waters. For many such metals, the problem is solved by designing compounds with coordination sites that are specific for that particular metal. For cases such as oxoanions, however, where the inorganic center is already fully coordinated by oxygens, different strategies need to be used. Chromate, phosphate, selenate, pertechnetate, and aluminate are such anions. These species are problematic contaminants in soils and waters because they are either toxic, environmentally undesirable, or radioactive. Furthermore, under both acidic and basic conditions, the coordination positions of these oxoanions are occupied by oxygens. Chromium(VI) as either chromate or dichromate presents a particular problem because it is a strong oxidizing agent. In this review the different methods of extracting this group of pseudotetrahedral oxoanions are discussed, along with the individual advantages and limitations of each strategy.     

Synthesis and Characterization of Calix[4]arene Functionalized Poly(ethylene glycol) Derivatives

Calix[4]arenes with both ligating and methoxy poly(ethylene glycol) groups appended have been synthesized using several approaches, involving the formation of sulfonyl ester groups on the wide rim, Schiff base derivatives on the narrow rim, and thioether groups on both the wide and narrow rims. These new derivatives have been characterized by a combination of infrared and ¹H NMR spectroscopy. Compounds 10 and 11 are insoluble in both water and aqueous poly(ethylene glycol), but the other new compounds are soluble.     

KMgF3:Ni2+晶体的占位、局部结构、吸收光谱和顺磁g因子的统一解释

利用完全对角化方法和强场耦合方案,采用半自洽场(semi-SCF)自由Ni2+的d轨道模型和Ni2+-6X-(x=F,Cl,Br,I)络合物的μ-κ-α模型研究,建立了含有过渡族金属离子的晶体的局域结构与吸收光谱和顺磁g因子之间的定量关系,对KMgF3:Ni2+晶体的占位、局域结构、吸收光谱和顺磁g因子作出了统一解释,预测了KMgF3:Ni2+晶体的光谱精细结构.所得理论计算结果与实验值符合得很好.