掺铒a-Si∶H,O薄膜1.54μm光致发光和微结构

国家自然科学基金,国家攀登计划

铒、氧共注a-Si:H和a-SiCx:H的1.54μm光致发光

在a-Si:H和a-SiCx:H中共注稀土铒和氧。300 ℃和400 ℃热退火后,测得了来自发光中心Er~(3+)内层4f电子跃迁的1.54 μm光致发光。400 ℃是较好的退火温度。随着碳含量的增加,发光强度逐渐减弱,这可能是由于碳的引入减弱了间隙氧退火时的迁移能力所致。

Er离子在Inp、GaAs和Si中的1.54μm特征发光峰

分别在InP、GaAs和Si中以7×10＜′14＞和1×10＜′15＞cm＜′－2＞的剂量进行Er离子注入, 并采用闭管、快速和炉退火等热处理。低温光致发光（PL）、反射式高等电子衍射和卢瑟福背散射实验研究表明, 上述样品中Er＜′3＋＞离子特征发光的中心波长均出现在1．5μm处, 其中InP的发光峰最强, 而注入损伤的恢复是影响Er＜′3＋＞发光的重要因素之一。卢瑟福背散射分析进一步证实退火后Er原子在Si中向表面迁移, 而在InP中的外扩散较小, 并比较了Er在InP和Si晶格中的占位情况。图7参12

1.54 mu m near-infrared photoluminescent and electroluminescent properties of a new Erbium (111) organic complex

The crystal structure of Er(PM)(3)(TP)(2) [PM = 1-Phenyl-3-methyl-4-isobutyryl-5-pyrazoloiie, TP = triphenyl phosphine oxide] was reported and its photoluminescence properties were studied by UV-vis absorption, excited, and emission spectra. The Judd-ofelt theory was introduced to calculate the radiative transition rate and the radiative decay time of 3.65 ms for the I-4(13/2) -> I-4(15/2) transition of Er3+ ion in this complex.

A novel terbium (III) beta-diketonate complex as thin film for optical device application

A novel terbium complex, Tb(acac)(3)AAP (acac: acetylacetone, AAP: 4-amino-antipyrine), was synthesized and its luminescent properties were studied. When it was used as an emitting center, triple-layer-type device with a structure of glass substrate/ITO (indium-tin oxide)/TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine)./Tb(acac)(3)AAP/PBD (2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole) or Alq(3) (tris(8-hydroxyquinolinato) aluminum)/Al (aluminum) exhibited bright characteristic emission of terbium ion upon applying d.c. voltage. The maximum luminance of the device is 56 cd/m(2) at 19 V and the maximum luminance efficiency is 0.357 lm/W.

1.54 mu m infrared photoluminescence and electroluminescence from an erbium organic compound

Infrared emission at 1.54 mu m excited optically and electrically from an erbium organic compound tris(acetylacetonato)(1,10-phenanthroline) erbium [Er(acac)(3)(phen)] is observed. The rare-earth complex is dispersed into a polymer matrix of poly(N-vinylcarbazole) (PVK) to fabricate an electroluminescent (EL) device with an ITO/PVK:Er(acac)(3)(phen)/Al:Li/Ag structure, where ITO represents indium-tin-oxide-coated glass. The device shows infrared EL emission at 1.54 mu m, which suggests a simple and cheap method to obtain a light source for 1.54-mu m-wavelength devices in optical communications. (C) 2000 American Institute of Physics. [S0021-8979(00)00301-7].

Studies on the energy band structures and chemical bond properties of LaX(X=N, P, As, Sb) crystals

The energy band structures of LaX(X=N, P, As, Sb) crystals have been studied by using LMTO-ASA method. The calculated energy gaps of these crystals are 2. 30 eV for LaN, 2. 05 eV for LaP, 1. 66 eV for LaAs and 1. 34 eV for LaSb. The results are in good agreement with experimental data, At the same time, using these calculated results of energy band structures of these crystals, the chemical bond properties have been analyzed and calculated, The covalency values of these crystals are 26.15% for LaN, 32.54% for LaP, 33.30% for LaAs and 36.49% for LaSb, which agree satisfactorily with the calculated ones by using PV (Phillips-Vechten) theory.

Binding and degradation of fibrinogen by Bacteroides fragilis and characterization of a 54 kDa fibrinogen-binding protein

Bacteroides fragilis is a bacterium that resides in the normal human gastro-intestinal tract; however, it is also the most commonly isolated Gram-negative obligate anaerobe from human clinical infections, such as intra-abdominal abscesses, and the most common cause of anaerobic bacteraemia. Abscess formation is important in bacterial containment, limiting dissemination of infection and bacteraemia. In this study, we investigated B. fragilis binding and degradation of human fibrinogen, the major structural component involved in fibrin abscess formation. We have shown that B. fragilis NCTC9343 binds human fibrinogen. A putative Bacteroides fragilis fibrinogen-binding protein, designated BF-FBP, identified in the genome sequence of NCTC9343, was cloned and expressed in Escherichia coli. The purified recombinant BF-FBP bound primarily to the human fibrinogen Bß-chain. In addition, we have identified fibrinogenolytic activity in B. fragilis exponential phase culture supernatants, associated with fibrinogenolytic metalloproteases in NCTC9343 and 638R, and cysteine protease activity in YCH46. All nine clinical isolates of B. fragilis examined degraded human fibrinogen; with eight isolates, initial A-chain degradation was observed, with varying Bß-chain and -chain degradation. With one blood culture isolate, Bß-chain and -chain degradation occurred first, followed by subsequent A-chain degradation. Our data raise the possibility that the fibrinogen-binding protein of B. fragilis, along with a variety of fibrinogenolytic proteases, may be an important virulence factor that facilitates dissemination of infection via reduction or inhibition of abscess formation.

Drusen prevalence and pigmentary changes in Caucasians aged 18-54 years

Aims and Purpose The aim of this study was to describe the prevalence and characteristics of drusen and pigmentary changes in a middle-aged population.

Methods Retinal images from 500 individuals aged 18–54 years were included. The source of participants was two UK optometry practices. Retinal images were graded using the Wisconsin Age-Related
Maculopathy Grading System. However, owing to the relatively young age of the population studied, a new category of drusen of smaller size (o31.5mm) was introduced.

Results Drusen were identi?ed within the central macular grid in 91.48% of all gradable eyes and in 444 subjects. Drusen sized o31.5mm were present in 89.7% of eyes, drusen sized 431.5mm and o63mm were present in 45.9% of all eyes and drusen 463mm and o125mm were present in only 1.7% of eyes. No eye had drusen larger or equal to 125mm. Very few eyes (1.2%) showed pigmentary changes within the grid. Drusen load increased with increasing age, P o0.001.

Conclusions The frequency of drusen in a younger Caucasian population aged 18–54 years is high, with 91.48% of all gradable eyes having drusen. The most frequent drusen subtype was hard distinct drusen o31.5mm. No druse greater or equal in size to 125mm was seen. Pigmentary changes are rare. Eye(2012) 26, 1357–1362; doi:10.1038/eye.2012.165; published online 17 August 2012