Site Occupation and Activity of Catalyst Nanoparticles Monitored by In Situ Vibrational Spectroscopy

2003 ◽  
Vol 42 (26) ◽  
pp. 3035-3038 ◽  
Author(s):  
Viktor Johánek ◽  
Swetlana Schauermann ◽  
Mathias Laurin ◽  
Jörg Libuda ◽  
Hans-Joachim Freund
2009 ◽  
Vol 96 (2) ◽  
pp. 345-356 ◽  
Author(s):  
Orsolya Hakkel ◽  
Zoltán Pászti ◽  
Tamás Keszthelyi ◽  
Krisztina Frey ◽  
László Guczi

1998 ◽  
Vol 120 (1) ◽  
pp. 203-204 ◽  
Author(s):  
Ruchama Fraenkel ◽  
Gordon E. Butterworth ◽  
Colin D. Bain

2001 ◽  
Vol 123 (27) ◽  
pp. 6732-6733 ◽  
Author(s):  
Arndt Heerwagen ◽  
Martin Strobel ◽  
Michael Himmelhaus ◽  
Manfred Buck

2019 ◽  
Vol 55 (4) ◽  
pp. 541-544 ◽  
Author(s):  
Shuji Ye ◽  
Junjun Tan ◽  
Kangzhen Tian ◽  
Chuanzhao Li ◽  
Jiahui Zhang ◽  
...  

Coherent degenerate infrared-infrared-visible sum frequency generation vibrational spectroscopy provides a powerful label-free probe for identifying the vibrational modes that are coupled through the electronic states in situ and in real time.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5554
Author(s):  
Francesca Ravera ◽  
Esen Efeoglu ◽  
Hugh J. Byrne

Stem cell technology has attracted considerable attention over recent decades due to its enormous potential in regenerative medicine and disease therapeutics. Studying the underlying mechanisms of stem cell differentiation and tissue generation is critical, and robust methodologies and different technologies are required. Towards establishing improved understanding and optimised triggering and control of differentiation processes, analytical techniques such as flow cytometry, immunohistochemistry, reverse transcription polymerase chain reaction, RNA in situ hybridisation analysis, and fluorescence-activated cell sorting have contributed much. However, progress in the field remains limited because such techniques provide only limited information, as they are only able to address specific, selected aspects of the process, and/or cannot visualise the process at the subcellular level. Additionally, many current analytical techniques involve the disruption of the investigation process (tissue sectioning, immunostaining) and cannot monitor the cellular differentiation process in situ, in real-time. Vibrational spectroscopy, as a label-free, non-invasive and non-destructive analytical technique, appears to be a promising candidate to potentially overcome many of these limitations as it can provide detailed biochemical fingerprint information for analysis of cells, tissues, and body fluids. The technique has been widely used in disease diagnosis and increasingly in stem cell technology. In this work, the efforts regarding the use of vibrational spectroscopy to identify mechanisms of stem cell differentiation at a single cell and tissue level are summarised. Both infrared absorption and Raman spectroscopic investigations are explored, and the relative merits, and future perspectives of the techniques are discussed.


2013 ◽  
Vol 20 (5) ◽  
pp. 683-690 ◽  
Author(s):  
Hongxin Wang ◽  
Yoshitaka Yoda ◽  
Weibing Dong ◽  
Songping D. Huang

The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) anin situcalibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-57Fe-enriched [Fe4S4Cl4]=and 10%-57Fe and 90%-54Fe labeled [Fe4S4Cl4]=has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3–4 h to about 30 min. Although the quick-switching calibration is notin situ, it is suitable for normal NRVS measurements.


2013 ◽  
Vol 740-742 ◽  
pp. 209-212 ◽  
Author(s):  
Rooban Venkatesh K.G. Thirumalai ◽  
Bharat Krishnan ◽  
Albert Davydov ◽  
Joseph Neil Merrett ◽  
Yaroslav Koshka

A method was developed for growing SiC nanowires without depositing a metal catalyst on the targeted surfaces prior to the CVD growth. The proposed method utilizes in-situ vapor-phase catalyst delivery via sublimation of the catalyst from a metal source placed in the hot zone of the CVD reactor, followed by condensation of the catalyst-rich vapor on the bare substrate surface to form the catalyst nanoparticles. The vapor-phase catalyst delivery and the resulting nanowire density was found to be influenced by both the gas flow rate and the catalyst diffusion through the boundary layer above the catalyst source. The origin of undesirable bushes of nanowires and the role of the C/Si ratio were established.


Sign in / Sign up

Export Citation Format

Share Document