从烟化炉渣中回收镓的研究概况

韶关冶炼厂每年产鼓风(烟化)炉水淬渣15万t，其中含Ga30—40t，铁4万t左右，且历年堆放水淬渣近200万t，含Ga达400～500t，以现价计，高达十数亿人民币。韶冶开发部及其它科研院所的科研工作者对韶冶镓回收做了大量的工作。主要以以下四种方法为主：高温氯化挥发法、全湿法流程回收镓、碱熔-浸出法、还原熔炼-电解法等。其中以还原熔炼-电解法的各项指标较为理想，并通过工业试验证明该方案是可行的。     

半绝缘砷化镓晶片中碳的微区分布

通过化学腐蚀(AB腐蚀液)、金相显微镜观察、透射电镜(TEM)及能谱分析(EDX)，对LEC法生产的半绝缘砷化镓(SI-GaA8)单晶中碳的傲区分布进行了分析。其结果表明：碳的微区分布与晶片中位错密度及分布存在对应关系。高密度位错区位错形成胞状结构，该结构的胞壁区碳含量高，近胞壁区次之，剥光区碳含量低于检测限。     

钛石膏作水泥缓凝剂研究

介绍了钛石膏中的杂质组成与形态,以及用钛石膏作水泥缓凝剂时,杂质对水泥性能的影响.研究结果表明,钛石膏中杂质主要为Fe(OH)3、FeSO4和Al(OH)3.杂质对水泥性能影响不大,不经预处理作水泥缓凝剂,其性能与采用天然石膏的水泥相当.     

磷石膏颗粒级配、杂质分布对其性能影响的研究

采用激光粒度测定仪、筛分和SEM研究了磷石膏的颗粒级配和二水石膏晶体的形貌，测定了不同粒径磷石膏中杂质的种类和含量，测试了不同粒径磷石膏的性能。结果表明：磷石膏的颗粒级配、形貌与天然石膏存在明显不同，磷石膏中的杂质含量随粒径不同而存在差异。     

Percolation, Fractal Behavior, and High-Tc Superconductivity

Hole suppliers like Sr in doped La₂CuO₄ are mainly randomly distributed. Assuming that the holes are dislocated over a few lattice constants away from the Sr atom, the conducting areas form randomly distributed circles in the CuO₂ layer planes. Conductivity and also superconductivity can occur only when these circles touch each other and form percolation clusters. Mobile holes are accompanied by diffusing d-electrons. Their spin direction is no longer localized on distinct places, and antiferromagnetism breaks down. The phase diagram of high-T _c superconductors is discussed on the basis of a modified continuum percolation model for which the centers of each circle are located on lattice points. The inhomogeneities due to the random hole distributions lead to broad peaks instead of sharp singularities in the static and dynamic response functions.     

有关烧结部件表面问题的几个案例

烧结钢部件在生产过程中，尤其是烧结之后其表面有时会出现针孔、孔洞及斑痕等缺陷。本文结合PM生产的实际过程，总结了影响部件表面问题的各种因素，并举例分析如何诊断各种不同的表面问题及其解决方案。     

感耦等离子体原子发射光谱法测定高纯铅中杂质元素的干扰研究

文章介绍了用ＩＣＰ－ＡＥＳ法测定高纯铅中杂质元素时，Ｐｂ对分析元素的干扰情况。Ｐｂ对Ｇｅ、Ｍｏ、Ｐ、Ａｓ、Ｆｅ、Ｂｉ、Ｍｎ有背景影响，对Ｓｂ产生谱线干扰。１０ｍｇ／ｍｌ的Ｐｂ分别产生相当于０．２３５μｇ／ｍｌＡｓ、０．７５０μｇ／ｍｌＰ、０．３３５μｇ／ｍｌＭｏ和３．９５０μｇ／ｍｌＳｂ的信号。     

高分辨ICP-MS测定电子级高纯异丙醇中杂质元素

利用高分辨电感耦合等离子体质谱测定电子级高纯异丙醇中的痕量金属杂质,用膜去溶进样系统直接进样,用标准加入法进行上机检测,无需前处理、快速,避免了在样品前处理时的污染问题。高分辨电感耦合等离子体质谱可以消除多分子离子干扰,降低检出限,提高定量准确性。方法的检出限为0.45~20.79 ng/L,加标法回收率为88.2%~102.6%。方法简单,结果可靠,适用于高纯异丙醇中痕量元素的快速测定。     

Theoretical study of the zero-gap organic conductor α-(BEDT-TTF)2I3

Abstract

The quasi-two-dimensional molecular conductor α-(BEDT-TTF)₂I₃ exhibits anomalous transport phenomena where the temperature dependence of resistivity is weak but the ratio of the Hall coefficient at 10 K to that at room temperature is of the order of 10⁴. These puzzling phenomena were solved by predicting massless Dirac fermions, whose motions are described using the tilted Weyl equation with anisotropic velocity. α-(BEDT-TTF)₂I₃ is a unique material among several materials with Dirac fermions, i.e. graphene, bismuth, and quantum wells such as HgTe, from the view-points of both the structure and electronic states described as follows. α-(BEDT-TTF)₂I₃ has the layered structure with highly two-dimensional massless Dirac fermions. The anisotropic velocity and incommensurate momenta of the contact points, ±k₀, originate from the inequivalency of the BEDT-TTF sites in the unit cell, where ±k₀ moves in the first Brillouin zone with increasing pressure. The massless Dirac fermions exist in the presence of the charge disproportionation and are robust against the increase in pressure. The electron densities on those inequivalent BEDT-TTF sites exhibit anomalous momentum distributions, reflecting the angular dependences of the wave functions around the contact points. Those unique electronic properties affect the spatial oscillations of the electron densities in the vicinity of an impurity. A marked behavior of the Hall coefficient, where the sign of the Hall coefficient reverses sharply but continuously at low temperatures around 5 K, is investigated by treating the interband effects of the magnetic field exactly. It is shown that such behavior is possible by assuming the existence of the extremely small amount of electron doping. The enhancement of the orbital diamagnetism is also expected. The results of the present research shed light on a new aspect of Dirac fermion physics, i.e. the emergence of unique electronic properties owing to the structure of the material.     

Enthalpies of mixing of liquid Ag–Ga,Cu–Ga and Ag–Cu–Ga alloys

Using MHTC 96 Setaram high temperature drop calorimeter, partial and integral enthalpies of mixing of liquid alloys were determined in the Ag–Ga, Cu–Ga and in the ternary Ag–Cu–Ga system. The ternary alloys were investigated along two cross-sections at two different temperatures: 1128 K and 1273 K, respectively. Experimental data were used to find ternary interaction parameters by applying the Redlich–Kister–Muggianu model for substitutional solutions, and a full set of parameters describing the concentration dependence of the enthalpy of mixing was derived. The experimental data indicate that the heat of mixing in this system is slightly temperature dependent, at least in the measured temperature range.