Band gaps and defect levels in functional oxides

Most ab-initio calculations of the electronic structure use the local density approximation, which gives good structural data but severely underestimates the band gaps of semiconductors and insulators. This paper presents calculations of the band structures and oxygen vacancy levels of some important oxide semiconductors and insulators, using density functional methods which do give more accurate band gaps. The materials SnO₂, Cu₂O, SrCu₂O₂, CuAlO₂, SrTiO₃, HfO₂, ZrO₂, La₂O₃, ZrSiO₄, and SiO₂ are covered.     

龙滩大法坪砂石加工系统圆筒洗石机的改造

介绍大法坪砂石加工系统圆筒洗石机的使用中存在的问题和缺陷，并对其原因进行分析，提出解决的措施和改造。通过解决圆筒洗石机振动和链条润滑不充分等关键缺陷问题后提高了设备的利用率和运行效率，发挥了圆筒洗石机的效能。     

优化锰铁高炉配矿结构

介绍了通过优化高炉锰铁烧结矿原料结构，改善了烧结矿性能，使锰铁冶炼取得了增产、节焦、降成本的明显效果。     

龙滩水电站大坝混凝土供料线的优化设计

龙滩水电站大坝为碾压混凝土重力坝，大坝混凝土总量约580万m^3，其中碾压混凝土约362万m^3，每条混凝土供料线的平均输送能力为300m^3／h，是水电工程之最。龙滩大坝混凝土供料线系统由拌和楼出料皮带机和系统连接皮带机、3条高速皮带机供料线、3条负压溜槽和2台塔式布料机组成。如何保证混凝土在运输过程中的均匀性及和易性，尽量缩短运输时间，减少倒运次数，保证人仓强度，是混凝土供料线系统布置、设计的重点。     

Phase Transition VO2 Thin Films for Optical Switches

This paper presents a method to make vanadium dioxide (VO₂) crystallites on silicon substrates by reactive ion beam sputtering. The thickness of the thin film is about 100nm. The phase transition temperature of VO₂ is 65°C. The transmittance of the semiconducting phase VO₂ is about 50% and it is reduced to as low as 3% in metal phase at the infrared wavelenghth spectrum. The extinction ratio of the optical switches is 12dB. and the insertion loss is of 1-2dB. The switching time is about 1ms.     

Quilone试剂改性脲醛树脂——新型防水涂料的制备

叙述了Quilone试剂的合成,改性脲醛树脂的原理、实验方法、改性后脲醛树脂的抗水性、抗渗透性、耐化学药品性及其影响因素。     

Induction of immune tolerance with heart-thymus composite allotransplantation in rats

Objective To study on the role of thymus transplantation for heart allograft in rats. Methods Vascularized heart-thymus combined transplantation was performed with microsurgical technique. Graft survival, histopathology, level of IL-2, IL-4 and its mRNA expression in serum and cardiac grafts were investigated. Results Heart-thymus combined transplantation achieved effect in the prolongation of cardiac graft survival with short-term administration of cyclosporine. Conclusions Vascularized thymus transplantation induced immune tolerance in thymectomized rats.     

渭河流域水利水保措施减水减沙效益初步分析

截止1989年底,渭河流域共有水库361座,塘坝2666座,引水有效灌溉面积40.4万公顷,治理总面积8136km~2,治理度17.1％。以1970年为效益计算起始年,并将全流域划分为18个片,分别采用水文法和水保法计算1970～1989年间各项水利水保措施减水减沙量及综合减水减沙效益。水文法算得的综合减水效益为24.1％,减沙效益为30.6％;水保法算得的结果相应为29.9％和30.8％,两者相近。