化学合成法试制超细超导体瓷料的新工艺

研究了超细超导体瓷料用化学合成法试制的新工艺。通过将溶液中的超导阳离子均匀沉淀、烘干、煅烧后得到成分和粒度分布均匀的超微细瓷料。     

利用RTS噪声确定MOSFET氧化层中陷阱位置的方法

强场诱生并与电场奇异性相关的边界陷阱是影响深亚微米MOS器件可靠性的关键因素之一.文中研究了深亚微米MOS器件的随机电报信号(RTS)的时间特性,提出了一种通过正反向测量器件非饱和区噪声的手段来确定边界陷阱空间分布的新方法.对0.18μm×0.15μm nMOS器件的测量结果表明,利用该方法可以准确计算深亚微米器件氧化层陷阱的二维位置,还为深亚微米器件的可靠性评估提供了一种新的手段.     

Deep levels in bulk LEC single crystal IxGa1-xAs

Bulk single crystals of In_xGa_1-xAs (0.01 <x < 0.12) were successfully grown by the Liquid Encapsulated Czochraski (LEC) technique. These crystals are of high quality and can provide tunable substrate material for epitaxial application, since the lattice constant may be adjusted by varying the composition. Nominally undoped crystals were semi-insulating as grown ifx is less than about 0.05. Semi-insulating crystals with higher In composition can be obtained by chromium doping during crystal growth. The asgrown crystals were studied by 4.2 K photoluminescence spectroscopy (PL) and thermally stimulated current spectroscopy (TSC). Results from PL measurements indicate good crystal quality and impurity control. TSC spectra reveal several bulk traps in undoped and Cr doped semi-insulating samples. The activation energies of these traps decrease as In composition is increased. The amount of change in activation energy is about one third of the bandgap shrinkage due to increased In concentration.     

煤基炭材料的结构及其嵌锂行为

以兖州煤为原料 ,在 70 0～ 10 0 0℃下热裂解制备煤基炭材料。氮气物理吸附和X射线衍射分别考察了炭材料的BET比表面积、孔容以及微晶结构的变化 ;并将炭材料制作成电极以考察其嵌锂行为。研究发现随着热处理温度的升高 ,煤基炭材料的微晶结构变得有序 ,而BET比表面积、孔容以及首次充放电可逆容量呈现下降趋势。在 70 0℃下热裂解所制备的炭材料 ,其放电容量高达 470mAh/ g。     

弹流润滑状态测试仪的研制及其应用

在深入研究文氏桥电路的基础上研制了ＥＨＬ－Ｃ型润滑状态测试仪。文中阐述了仪器的特点，给出测试所需标定曲线的绘制过程。最终通过高速滚动轴承的测试分析，证明了仪器的可行性，具有推广的价值。     

开展SPECT影像MonteCarlo模拟和高性能低价格SPECT的研制

在ＳＰＥＣＴ的硬件和软件研制中，ＭｏｎｔＣａｒｌｏ模拟是重要的手段，我们正在研制高性能低价格的ＳＰＥＣＴ，本文介绍这个领域研究工作。     

Fibroblast growth factor-2 alters the effect of eroding polylactide-polyglycolide on osteogenesis in the bone chamber

The effects of recombinant human fibroblast growth factor-2 (rhFGF-2) in the presence of eroding 50:50 poly(DL-lactide-co-glycolide) (PDLLG) on acute bone healing were studied in the optical bone chamber (BCI). BCIs were loaded with disks of PDLLG surrounded by one of four rhFGF-2 doses. Fifty-two female rabbit right tibias were implanted. Commencing the third week post implantation (W3) healing in the BCI compartment was observed weekly, using intravital microscopy, until W8. The doses were: unloaded, loaded with polymer only, and polymer plus 0.5, 1.0, and 10 microg rhFGF-2. Videotaped and photographed bone images were measured and analyzed using a frame-grabber digitizing system. Comparison with controls revealed that ossification rates were significantly above normal in rabbits loaded with polymer plus any of the rhFGF-2 doses. Comparison with polymer-only BCIs showed that PDLLG plus any of the three rhFGF-2 doses was linked with ossification rates significantly higher than baseline. The results indicated that FGF-2 in the dose range studied effectively can overcome the retarding effects of eroding polymer on ossification that has been reported by this laboratory. Interpretation of the retarding effects of the polymer disks, although consistent with previously studied washer-shaped devices of the same material, was complicated by a difference in erosion rate. This result supports the notion that erodible device geometry is a major factor in determining biocompatibility and must be considered in the design of carriers. Accordingly, programming of dose specificity for delivering a given polypeptide cytokine to a given host site must allow for the inhibitory effects of an eroding carrier and the influence of device geometry on these effects and erosion.     

Fields in the focal region of a spherical reflector

An earlier analysis of the field structure and energy flow near the axis of any circularly symmetric focusing reflector is applied to the case of a spherical reflector. From the results an estimate is made of the attainable efficiency of corrugated-waveguide aperture-type feeds.     

Rare earth industry in China

Before 1949, the year the People's Republic of China was founded, there was hardly any rare earth industry in China. Through the efforts made in the past thirty years however, substantial changes have taken place. An attempt is made here to look at the course we have followed and the present situation.     

Synthesis and characterization of hyperbranched azobenzene-containing polymers via self-condensing atom transfer radical polymerization and copolymerization

We report on the synthesis of an azobenzene-containing inimer 6-{4-[4-(2-(2-bromoisobutyryloxy)hexyloxy)phenylazo]phenoxy}hexyl methacrylate (I) and used it to prepare hyperbranched homopolymer and copolymers by self-condensing vinyl polymerization (SCVP) and copolymerization (SCVCP) with its precursor 6-{4-[4-(6-hydroxyhexyloxy)phenylazo]phenoxy}hexyl methacrylate (M) using atom transfer radical polymerization (ATRP). Depending on the comonomer ratio, γ=[M]₀/[I]₀, branched polymethacrylates with number-average weights between 8000 and 20,000 and degree of branching (DB) between 0.08 and 0.49 were obtained by SCVCP, as evidenced by GPC and ¹H NMR analysis. In addition, the photochemical properties of the polymers were also studied by UV-vis spectra and found the structure of polymers affect obviously the trans-cis isomerization properties of the branched polymers.