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http://hdl.handle.net/10722/42572
2024-03-28T19:38:08ZHigh‐Performance Deep‐Red/Near‐Infrared OLEDs with Tetradentate [Pt(O^N^C^N)] Emitters
http://hdl.handle.net/10722/269398
Title: High‐Performance Deep‐Red/Near‐Infrared OLEDs with Tetradentate [Pt(O^N^C^N)] Emitters
Authors: Cheng, G; Wan, Q; Ang, WH; Kwong, CL; To, WP; Chow, PK; Kwok, CCG; Che, CM
Abstract: The emission properties of two series of tetradentate Pt(II) emitters in aggregation forms are studied by density functional theory (DFT), time‐dependent DFT calculations, and photoluminescence (PL) measurements. PL quantum yields (PLQYs) of the complexes bearing type‐I O^N^C^N ligands (Pt‐X‐1 and Pt‐X‐2) increase with the dopant concentration in thin film until 100% [pristine Pt(II) complexes]. For complexes bearing type‐II O^N^C^N ligands (Pt‐X‐3 to Pt‐X‐5), their PLQYs in thin film increase as the dopant concentration increases up to a certain threshold and then quickly decrease with further increase in dopant concentration. Organic light‐emitting devices (OLEDs) with neat and doped Pt(II) emitters are fabricated and characterized. High‐efficiency near‐infrared OLEDs with λmax exceeding 700 nm and external quantum efficiencies (EQEs) of up to 15.84% are realized by using a neat Pt‐X‐1 thin film as the emitting layer (EML). For this device, a high EQE of 11.19% is retained at high current density of 100 mA cm−2; by doping Pt‐X‐5 (26 wt%) into a co‐host structure EML, a red emission with λmax of 661 nm, Commission Internationale de l'Eclairage (CIE) coordinates of (0.63, 0.37), and EQE of 21.75% at 1000 cd m−2 are achieved.2019-01-01T00:00:00ZA study of pre-antibiotic bacteriology in 125 patients with necrotizing enterocolitis
http://hdl.handle.net/10722/210020
Title: A study of pre-antibiotic bacteriology in 125 patients with necrotizing enterocolitis
Authors: Chan, KL; Saing, H; Yung, RWH; Yeung, YP; Tsoi, NS
Abstract: Over a five-year period, 125 newborns with necrotizing enterocolitis (NEC) were managed by us. Their mean birthweight was 1700 g and mean maturity was 32 weeks. Before commencement of antibiotics, routine septic work-up was done in order to define the bacterial spectrum and antibiotic sensitivity. The study includes aerobic and anaerobic cultures of gastric and pharyngeal aspirates, blood cultures, umbilical swabs and culture of umbilical catheter tips in relevant cases. Peritoneal swab results were also analyzed if laparotomy was performed. Positive cultures were present in 45 patients (36%) with 55 positive specimens. Fifteen types of organism were isolated: the commonest was Enterobacter (29%), followed by E. coli (14.5%) and Klebsiella (13%). They were resistant to ampicillin and first-generation cephalosporin. These organisms were usually opportunistic pathogens. Overgrowth of them may be the cause of NEC. Regular review of the antibiotic sensitivity of these organisms allows prompt and appropriate choice of antibiotics. At the same time, antibiotic sensitivity for these organisms was analyzed to guide us in the choice of antibiotic therapy.1994-01-01T00:00:00ZAssessment Model of Radiation Doses to Humans and Native Biota
http://hdl.handle.net/10722/87979
Title: Assessment Model of Radiation Doses to Humans and Native Biota; 人及动植物的辐射剂量评价模式
Authors: Shang, Z; Leung, JKC
Abstract: 随着核能工业和核技术应用的发展,人们对放射性物质向环境排放的管理越来越重视,要求对处置放射性废物过程中可能对人和野生动植物产生的影响进行评价。要对释放到环境中的放射性所致辐照剂量进行评价,一定形式的环境评价模式是必不可少的。本文综合近年来辐射防护和放射生态学研究的进展,对建立辐射剂量评价模式的基本要求和未来研究重点进行了初步归纳。; With the development of nuclear industry and nuclear technology application, the management of environmental releases of radioactive materials has attracted increasing attention, which leads to need of environmental impact assessment of radioactive waste disposal upon both human being and native biota. In order to assess the radiation doses caused by environmental radioactivity, certain type of environmental assessment mode will be necessary. Based on the progress achieved in the recent years, both in radiation protection and in radioecologlcal research aspect, this paper presents a brief summary of the basic requirements of developing the model and the important topics in the future.2000-01-01T00:00:00ZAn integrated particle sampler and lung radiation dosimeter
http://hdl.handle.net/10722/42675
Title: An integrated particle sampler and lung radiation dosimeter
Authors: Leung, JKC; Tso, MYW; Li, SH; Lam, HC; Poon, AS; Xiao, DT; Zhou, QF
Abstract: A lung dosimeter that can record the nonradiological hazard of aerosol particles to the lung as well as the radiological hazard of air borne radionuclides that are attached to aerosol particles has been developed. The dosimeter is capable of recording aerosol particles of diameters from 10-2 μm to 102 μ by electrostatic collection in a specially designed dosimeter body. The aerosol size distribution is recorded on a mylar strip and the activity size distribution of α, β, and γ radiation emitting aerosols recorded on another strip coated with α-Al2O3:C. Both strips can be read by a specially built reader, the output of which can be used to calculate the nonradiological hazard and radiological hazard, respectively, and to give an overall picture of the exposure.2003-01-01T00:00:00Z