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排序方式: 共有171条查询结果,搜索用时 875 毫秒
71.
L. Debarge J. P. Stoquert A Slaoui L. Stalmans J. Poortmans 《Materials Science in Semiconductor Processing》1998,1(3-4)
Rapid thermal oxidation with dry oxygen has been carried out on porous silicon (PS) films formed by electrochemical etching. The purpose of the paper was to investigate the surface passivation capability of the oxidized PS layers and to understand the oxidation mechanism. Rutherford back scattering (RBS) and X-ray photoemission spectroscopy (XPS) analyses confirmed the formation of a stoichiometric quasi-silicon dioxide. Besides, elastic recoil diffusion analysis (ERDA) demonstrated that a high concentration of hydrogen is still present in the PS film even after oxidation. RTO resulted in a good surface passivation effect at high temperature (>1000°C) as seen by internal quantum efficiency analysis. However, lifetime in bulk silicon is affected by the RTO process. 相似文献
72.
An Interdiffusion Method for Highly Performing Cesium/Formamidinium Double Cation Perovskites 下载免费PDF全文
Weiming Qiu Aniruddha Ray Manoj Jaysankar Tamara Merckx Joao P. Bastos David Cheyns Robert Gehlhaar Jef Poortmans Paul Heremans 《Advanced functional materials》2017,27(28)
The fabrication of high‐quality cesium (Cs)/formamidinium (FA) double‐cation perovskite films through a two‐step interdiffusion method is reported. Csx FA1‐x PbI3‐y(1‐x )Bry(1‐x ) films with different compositions are achieved by controlling the amount of CsI and formamidinium bromide (FABr) in the respective precursor solutions. The effects of incorporating Cs+ and Br? on the properties of the resulting perovskite films and on the performance of the corresponding perovskite solar cells are systematically studied. Small area perovskite solar cells with a power conversion efficiency (PCE) of 19.3% and a perovskite module (4 cm2) with an aperture PCE of 16.4%, using the Cs/FA double cation perovskite made with 10 mol% CsI and 15 mol% FABr (Cs0.1FA0.9PbI2.865Br0.135) are achieved. The Cs/FA double cation perovskites show negligible degradation after annealing at 85 °C for 336 h, outperforming the perovskite materials containing methylammonium (MA). 相似文献
73.
Bloemen K Hooyberghs J Desager K Witters E Schoeters G 《Proteomics. Clinical applications》2009,3(4):498-504
Exhaled breath condensate (EBC) is a biological fluid that contains trace amounts of secreted pulmonary proteins, and is emerging as a potentially valuable and non-invasively obtained source of disease biomarkers. Proteome analysis of these samples could lead to the identification of prognostic indicators of airway diseases. The objective of this study was to develop a protocol for proteome analysis of EBC samples. In this report, an improved procedure for EBC sample preparation and concentration is presented, together with a method for comparison of the protein profiles between two groups. The presented approach enabled to study the condensed exhaled breath proteome for biomarker analysis, and revealed proteins not previously identified in an EBC proteomics approach. In a comparative pilot study, EBC protein profiles obtained from smokers and non-smokers showed distinct differences and are illustrative for its potential in clinical studies. EBC from smokers contained higher concentrations of the more abundant proteins, such as cytokeratins, compared to non-smokers, and calgranulin B was identified uniquely in EBC samples from smokers. 相似文献
74.
Changes of gas quantity in a system can be measured either by measuring pressure changes or by measuring volume changes. As sensitive pressure sensors are readily available, pressure change is the commonly used technique. In many physiologic systems, however, buildup of pressure influences the gas exchange mechanisms, thus changing the gas quantity change rate. If one wants to study the gas flow in or out of a biological gas pocket, measurements need to be done at constant pressure. In this article we present a highly sensitive sensor for quantitative measurements of gas volume change at constant pressure. The sensor is based on optical detection of the movement of a droplet of fluid enclosed in a capillary. The device is easy to use and delivers gas volume data at a rate of more than 15 measurements/s and a resolution better than 0.06 microl. At the onset of a gas quantity change the sensor shows a small pressure artifact of less than 15 Pa, and at constant change rates the pressure artifact is smaller than 10 Pa or 0.01% of ambient pressure. 相似文献
75.
Beverley M. Dancy Dr. Nicholas T. Crump Daniel J. Peterson Dr. Chandrani Mukherjee Dr. Erin M. Bowers Dr. Young‐Hoon Ahn Dr. Minoru Yoshida Dr. Jin Zhang Dr. Louis C. Mahadevan Dr. David J. Meyers Dr. Jef D. Boeke Dr. Philip A. Cole 《Chembiochem : a European journal of chemical biology》2012,13(14):2113-2121
Histone acetyltransferase enzymes (HATs) are important therapeutic targets, but there are few cell‐based assays available for evaluating the pharmacodynamics of HAT inhibitors. Here we present the application of a FRET‐based reporter, Histac, in live‐cell studies of p300/CBP HAT inhibition, by both genetic and pharmacologic disruption. shRNA knockdown of p300/CBP led to increased Histac FRET, thus suggesting a role for p300/CBP in the acetylation of the histone H4 tail. Additionally, we describe a new p300/CBP HAT inhibitor, C107, and show that it can also increase cellular Histac FRET. Taken together, these studies provide a live‐cell strategy for identifying and evaluating p300/CBP inhibitors. 相似文献
76.
77.
Shuigen Huang Akhilesh Kumar Swarnakar Kim Vanmeensel Jef Vleugels 《Journal of the European Ceramic Society》2013,33(6):1237-1247
30 vol.% 2 and 30 μm diamond dispersed Si3N4 matrix composites were prepared by pulsed electric current sintering (PECS) for 4 min at 100 MPa in the 1550–1750 °C range. The densification behaviour, microstructure, Si3N4 phase transformation and stiffness of the composites were assessed, as well as the thermal stability of the dispersed diamond phase. Monolithic Si3N4 with 4 wt% Al2O3 and 5 wt% Y2O3 sintering additives was fully densified at 1550 °C for 4 min and 60 MPa. The densification and α to β-Si3N4 transformation were substantially suppressed upon adding 30 vol.% diamond particles. Diamond graphitisation in the Si3N4 matrix was closely correlated to the sintering temperature and grit size. The dispersed coarse grained diamonds significantly improved the fracture toughness of the diamond composite, whereas the Vickers hardness was comparable to that of the Si3N4 matrix ceramic. The Elastic modulus measurements were found to be an excellent tool to assess diamond graphitisation in a Si3N4 matrix. 相似文献
78.
Selective suppression of harmful cyanobacteria in an entire lake with hydrogen peroxide 总被引:2,自引:0,他引:2
Matthijs HC Visser PM Reeze B Meeuse J Slot PC Wijn G Talens R Huisman J 《Water research》2012,46(5):1460-1472
Although harmful cyanobacteria form a major threat to water quality, few methods exist for the rapid suppression of cyanobacterial blooms. Since laboratory studies indicated that cyanobacteria are more sensitive to hydrogen peroxide (H2O2) than eukaryotic phytoplankton, we tested the application of H2O2 in natural waters. First, we exposed water samples from a recreational lake dominated by the toxic cyanobacterium Planktothrix agardhii to dilute H2O2. This reduced the photosynthetic vitality by more than 70% within a few hours. Next, we installed experimental enclosures in the lake, which revealed that H2O2 selectively killed the cyanobacteria without major impacts on eukaryotic phytoplankton, zooplankton, or macrofauna. Based on these tests, we introduced 2 mg L−1 (60 μM) of H2O2 homogeneously into the entire water volume of the lake with a special dispersal device, called the water harrow. The cyanobacterial population as well as the microcystin concentration collapsed by 99% within a few days. Eukaryotic phytoplankton (including green algae, cryptophytes, chrysophytes and diatoms), zooplankton and macrofauna remained largely unaffected. Following the treatment, cyanobacterial abundances remained low for 7 weeks. Based on these results, we propose the use of dilute H2O2 for the selective elimination of harmful cyanobacteria from recreational lakes and drinking water reservoirs, especially when immediate action is urgent and/or cyanobacterial control by reduction of eutrophication is currently not feasible. A key advantage of this method is that the added H2O2 degrades to water and oxygen within a few days, and thus leaves no long-term chemical traces in the environment. 相似文献
79.
B. J. Pawlak T. Janssens S. Singh I. Kuzma‐Filipek J. Robbelein N. E. Posthuma J. Poortmans F. Cristiano E. M. Bazizi 《Progress in Photovoltaics: Research and Applications》2012,20(1):106-110
B implanted emitters are investigated in the back junction cell configuration and their material properties are tested in double side implanted Si wafers. B has been implanted at 5 keV at various dose conditions varying from 1 × 1014 up to 3 × 1015 at./cm2 and activated at 1000°C for 10 min. N‐type 8 × 8 cm2 mono‐crystalline cells are fabricated and measured. Both fill factor and efficiency increase for high‐B doses. However, at 1015 at./cm2 B dose the Voc drops, which is in agreement with lifetime degradation in the wafer. Defect evolution simulations of BnIm clusters formation is correlated with lifetime degradation. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
80.
Izabela Kuzma‐Filipek Frederic Dross Kris Baert Jose Luis Hernandez Sukhvinder Singh Kris Van Nieuwenhuysen Jef Poortmans 《Progress in Photovoltaics: Research and Applications》2012,20(3):350-355
We demonstrate the use of a copper‐based metallization scheme for the specific application of thin‐film epitaxial silicon wafer equivalent (EpiWE) solar cells with rear chemical vapor deposition emitter and conventional POCl3 emitter. Thin‐film epitaxial silicon wafer equivalent cells are consisting of high‐quality epitaxial active layer of only 30 µm, beneath which a highly reflective porous silicon multilayer stack is embedded. By combining Cu‐plating metallization and narrow finger lines with an epitaxial cell architecture including the porous silicon reflector, a Jsc exceeding 32 mA/cm2 was achieved. We report on reproducible cell efficiencies of >16% on >70‐cm2 cells with rear epitaxial chemical vapor deposition emitters and Cu contacts. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献