相对论性核与乳胶(Ag)碰撞中灰粒子的系统研究 *

用描写相对论性核 核碰撞的LUCIAE模型和相应的事件产生器系统地研究了 1 4.6 ,6 0和 2 0 0AGeV的O核、2 0 0AGeV的Si和S核以及 1 1 .6AGeV的Au核与乳胶 (Ag)碰撞中灰粒子产生的平均多重数、多重数分布以及角分布 3个物理量同入射能量、射弹质量及碰撞中心度间的关系 ,还研究了再散射在灰粒子产生机制中的作用 .LUCIAE的这些研究结果与相应的EMU0 1乳胶实验结果都相一致 .     

算术级数中的陈景润定理 *

设N为一充分大的偶数且q≥ 1 ,(l_i,q) =1 (i=1 ,2 ) ,l₁+l₂ ≡N(modq) .证明了方程N =p+P₂ ,p≡l1(modq) ,P₂ ≡l₂ (modq)对区间 1 ,N^1/37中除了ON^1/37log^-5 N个例外的整数q ,都有无穷多解 ,其中p是素数 ,P₂ 为一至多有2个素因子的殆素数 .     

涡旋成对分布和对二元速度关联函数的影响

本文考虑了涡旋之间相互作用的影响,假定均匀各向同性湍流场是由涡旋对在整个空间等几率分布而成,这样计算出的二元速度关联函数f(γ/λ)在远处略有提高,这个结果是与Bennett和Corrsin的实验结果和其他实验结果相合的。     

Valence and conduction bands in MPS3 layered compounds studied by synchrotron radiation

Summary With the resonant photomeission technique we investigated the valence bands of FePS₃ and NiPS₃. The experimental results, support the ionic picture of the compounds and our previous identification of the valence band structures. The structures rapidly varying in intensity when the excitation energy is scanned across the Fe and NiM _2,3 absorption edge are associated to the transition metal 3d states; the nonresonating features are ascribed to the (P₂P₆)⁴⁻ cluster states. With the yield technique we measured the high-resolution absorption spectra of the phosphorus and sulphur inner-core levels in Mn, Fe and Ni thiophosphates. TheL _2,3(P) andL _2,3(S) spectra are similar to each other in all the compounds and are interpreted in terms of the projected density of states of the conduction bands derived from the (P₂S₆)⁴⁻ cluster states. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Amorphous silicon-carbon films prepared by reactive evaporation

Summary An ion-beam-assisted deposition (IBAD) technique, based on reactive evaporation using hydrogen/ methane gas mixture, has been used for the preparation ofa-Si_1−x C _x : H films. Measurements are reported on the composition, optical gap, infra-red vibrational absorption bands and on the electrical dark-conductivity temperature dependence to verify the reliability of this deposition method. On increasing the compositional parameterx up to 0.35, the IR results show an increasing hydrogenation and the presence of Si-CH₃ units in addition to the ones with the carbon fully coordinated with the silicon, while the optical-gap and the dark-conductivity activation energies reached the values of 2.44 eV and 0.77 eV, respectively. The authors of this paper have agreed to not receive the proofs for correction     

The use of atmospheric pressure laser desorption mass spectrometry for the study of iron-gall ink

The study of ancient works of art is a very challenging task, mainly due to the impossibility of applying experimental approaches that could damage anyhow the object from which analytical information has to be obtained. Spatially resolved analytical methods have significantly enhanced our capacity to study ancient material since they cause minimal and at times no damage to the studied object. Unfortunately, only a few analytical techniques operating within the requested spatial resolution are applicable for the investigation of the organic components of artistic and archaeological objects. In this work, iron-gall ink was prepared according to ancient recipes and its composition was evaluated by AP/MALDI-MS. The latter is demonstrated to be a very valuable tool for the study of the organic components of ancient works of art as it combines the advantages of the vacuum MALDI-MS analytical approach to the possibility of analysing samples in air. In situ analyses were also carried out by analysing strokes of ink directly from paper and parchment. PACS 82.80.Ms; 61.66.Hq; 87.14.-g     

Molecular conformation of cyclenes: Part IX. Asymmetrical 1,3,6-cyclononatriene and 1,3,6-cyclodecatriene

The strain energy of the most probable conformers of 1,3,6-cyclononatriene and 1,3,6-cyclodecatriene, which are asymmetrical compounds, has been calculated as a function of various geometrical parameters by means of the semiempirical Hendrickson's treatment, partially modified. The most stable conformation of 1,3,6-cyclononatriene is a member of the all-cis family, while a transcis-trans structure is the most stable among the 1,3,6-cyclodecatriene conformations. In this latter compound however, the energy minima of the all-cis, trans-cis-cis, and cis-cis-trans conformers also appear to be close to each other. Some possible interconversions are also discussed.     

Transition entropies and mesomorphic behaviour of p-n-alkoxybenzyliden-p′-butoxyanilines

Calorimetric data on the mesogenic homologous series H₉C₄OC₆H₄NCHC₆H₄OC_nH_{2n + 1} are presented. Trends in the nematic-isotropic liquid transition temperatures, enthalpies and entropies are briefly discussed. A remarkable polymorphism is evidenced in several compounds. The importance of the thermal history of the samples in relation to their thermal behavior is shown.     

Quenched Li-containing multiple sulfate glasses

Over one hundred quenched melts containing lithium, other alkali, and/or alkali earth or other divalent metal sulfates were examined by differential thermal analysis and powder X-ray diffraction. Glasses formed in many of these quenches, but pure glass generally was obtained only in ternary compositions and even then only in limited concentration ranges. Ionic conductivities ranged up to 10^?3 (Ω cm)^?1. Systematic variations, of the Li concentration and of ionic sizes, for example, were investigated. No factors were found which could be clearly correlated with either the occurrence of glass or the magnitude of the ionic conductivity.     

X-ray photoelectron spectrum and two-dimensional band structure of InSe

The X-ray photoelectron spectrum of InSe is reported and interpreted on the basis of a tight-binding calculation which neglects interlayer interactions. The proposed band structure is also in reasonable agreement with the experimental energy bands recently obtained from angle-resolved photoemission.