Study of Kaon-Proton Elastic Scattering at High Energies

It ia shown that the differential cross section for both K⁺p and K^-p elastic scattering including the most recent measurements for 20 < pL < 200 (GeV/c) and with -t extended upto 28 (GeV/c)² can be fitted by using the pomeron as dipole and p as a simple pole. The difference of the total cross section for K⁺p and K^-p scattering is also explained.     

Fe掺杂TiO2和Fe2O3量子点共负载催化剂:吸附与光催化协同作用高效降解有机染料

光催化作为节能、清洁的环境处理技术,被广泛应用于污染物处理领域,如室内气体净化、尾气VOCs处理和水体有机污染降解等.在众多光催化剂中,TiO2以其良好的化学稳定性、无二次污染、无刺激性和安全无毒等优势得到广泛研究.然而TiO2是宽禁带材料,仅能吸收太阳光谱的紫外光部分,通常需要用紫外光源来激发,光生电子-空穴易复合,这限制了其应用.过渡金属离子掺杂能在TiO2价带之上形成新的掺杂能级,从而提高其光谱响应范围,提高全光谱反应活性; 与体相TiO2相比,纳米尺寸的TiO2具有更高的光催化活性,尤其小于10 nm的量子点尺寸TiO2有着高活性面积、较短的光生电子-空穴迁移路径和独特的量子尺寸效应; Fe2O3作为吸附材料与TiO2构建复合材料能够发挥吸附与光催化协同作用,从而提高污染物处理效率.我们以构建Fe掺杂TiO2和Fe2O3量子点共负载催化剂为目标,以钛酸四丁酯(TBT)和硫酸亚铁为前驱体,采用常温水解方法将Fe掺杂的TiO2量子点生长在MCM-41分子筛表面,并通过调节硫酸亚铁加入量合成了MCM-41负载的Fe掺杂TiO2和Fe2O3量子点催化剂.采用透射电子显微镜和X射线衍射研究了复合晶体结构,采用X射线光电子能谱、紫外-可见光谱和傅里叶变换红外光谱等表征手段研究了复合量子点材料生长机理和能带结构.结合吸附过程和光降解过程建立了吸附与光催化协同作用与污染物处理效率之间的关联关系.表征结果表明,硫酸亚铁水溶液加速TBT水解成功地在MCM-41表面生长了Fe掺杂TiO2量子点,并且量子点粒径随Fe前驱体量的增加而变大; 前驱体比例Ti/Fe ≤ 3.0时,过量的硫酸亚铁会析出并在焙烧过程中在MCM-41上分解为Fe2O3量子点,Fe2O3量随着硫酸亚铁加入量提高而增多.通过调节Fe前驱体的量,一方面Fe掺杂在二氧化钛价带之上形成了掺杂能级,减小了带隙,拓宽了光响应范围,另一方面引入适量Fe2O3量子点,实现了Fe掺杂TiO2和Fe2O3量子点共负载催化剂的构建.复合材料实现了吸附过程与光催化降解过程的协同作用,Fe2O3将污染物富集于催化剂表面,Fe掺杂TiO2将其有效降解,大大提高了污染物处理能力,其中FT/M-3.0处理效率最高,并在10次循环处理后依然维持较高的吸附能力和光催化降解能力.该工作为高效光催化水处理催化剂的设计和构建提供了新思路和策略.     

A first principle study of band structure of III-nitride compounds

The band structure of both phases, zinc-blende and wurtzite, of aluminum nitride, indium nitride and gallium nitride has been studied using computational methods. The study has been done using first principle full-potential linearized augmented plane wave (FP-LAPW) method, within the framework of density functional theory (DFT). For the exchange correlation potential, generalized gradient approximation (GGA) and an alternative form of GGA proposed by Engel and Vosko (GGA-EV) have been used. Results obtained for band structure of these compounds have been compared with experimental results as well as other first principle computations. Our results show a significant improvement over other theoretical work and are closer to the experimental data.     

Study of Fermilab data for the reaction π− p→ηn

Fermilab data for the angular distribution measurements of the reaction ^– p n are investigated and it is shown that a good fit with experiment is obtained by using a simple Regge pole model with phenomenological residue functions. The energy dependence in this case is found to be different from that for the d/dt/ data obtained at Serpukhov.Work supported by the Pakistan Science Foundation under contract No. P-PU-PHY(11/1).     

Total Cross Sections at High Energies—An Update

Current and future measurements for the total cross sections at E-811,PP2PP,CSM,FELIX,and TOTEM have been analyzed using various models.In the light of this study an attempt has been made to focus on the behavior of total cross section at very high energies.     

DIPOLE POMERON MODEL AND RECENT RESULTS ON PP ELASTIC SCATTERING

The dipole pomeron model has been used t of it the recent differential cross section data for pp elastics cattering.     

Hyperon-Neutron Elastic Scattering

It is shown that the Chou-Yang model can be extended to hyperon-neutron elastic reactions at high energies by assuming that the hadronic form factor of neutron is proportional to its magnetic form factor. It is also predicted that the scaling of magnetic form factor of neutron with charge as well as magnetic form factors of proton implies that the differential cross sections of corresponding hyperon-proton and hyperon-neutron reactions should be equal.     

STUDY OF THE REACTION K-p → πo Λ

It is shown that at high energy all available data for differential and integrated cross sections and the Λ-polarization in the reaction K^-p → π^o Λ can be fitted by using a simple Regge pole model with phenomenological residue functions. The characteristics of helicity and helicity non-flip amplitudes are also examined.     

Simple regge pole model for neutron-proton elastic scattering at high energies

It is shown that, by a phenomenological choice of residue functions, the most recent measurements of the differential cross section, the total cross section and the slope fornp elastic scattering from 70 to 400 GeV/c can be explained on simple Reggepole model. The predictions are also made regarding the energy dependence of dip and bump structure.