scholarly journals Focused Laser Spike Dewetting as a Rheology Method for Soft Matter Thin Films

Author(s):  
Tianxing Ma ◽  
Alex Liu ◽  
Michael P. Nitzsche ◽  
Yi Jin ◽  
Kyle Buznitsky ◽  
...  

<div>Focused laser spike (FLaSk) dewetting employs a localized heat source to create thermocapillary induced trench-ridge morphologies. By using a universal heating substrate to create a material independent thermal profile coupled with optical microscopy, we have studied the dewetted ridge feature for several distinct glassy thin films. The evolution of the ridge's radius over time can be modeled using stretched exponential functions to derive a maximum dewetted radius and a characteristic decay time. The characteristic decay time shows a super-Arrhenius behavior resembling viscosity change during the glass transition process. An effective viscosity is defined by balancing the thermocapillary Marangoni stress using the mean temperature in the melt pool, indicating clear signature of composition. In this way, we have demonstrated that FLaSk dewetting as a rheology</div><div>method can be employed for high-throughput analysis of glassy thin film materials at high temperature and shear.</div>

2021 ◽  
Author(s):  
Tianxing Ma ◽  
Alex Liu ◽  
Michael P. Nitzsche ◽  
Kyle Buznitsky ◽  
Adithya Sridhar ◽  
...  

<div>Focused laser spike (FLaSk) dewetting employs a localized heat source to create thermocapillary induced trench-ridge morphologies. By using a universal heating substrate to create a material independent thermal profile coupled with optical microscopy, we have studied the dewetted ridge feature for several distinct glassy thin films. The evolution of the ridge's radius over time can be modeled using stretched exponential functions to derive a maximum dewetted radius and a characteristic decay time. The characteristic decay time shows a super-Arrhenius behavior resembling viscosity change during the glass transition process. An effective viscosity is defined by balancing the thermocapillary Marangoni stress using the mean temperature in the melt pool, indicating clear signature of composition. In this way, we have demonstrated that FLaSk dewetting as a rheology</div><div>method can be employed for high-throughput analysis of glassy thin film materials at high temperature and shear.</div>


2021 ◽  
Author(s):  
Tianxing Ma ◽  
Alex Liu ◽  
Michael P. Nitzsche ◽  
Yi Jin ◽  
Kyle Buznitsky ◽  
...  

<div>Focused laser spike (FLaSk) dewetting employs a localized heat source to create thermocapillary induced trench-ridge morphologies. By using a universal heating substrate to create a material independent thermal profile coupled with optical microscopy, we have studied the dewetted ridge feature for several distinct glassy thin films. The evolution of the ridge's radius over time can be modeled using stretched exponential functions to derive a maximum dewetted radius and a characteristic decay time. The characteristic decay time shows a super-Arrhenius behavior resembling viscosity change during the glass transition process. An effective viscosity is defined by balancing the thermocapillary Marangoni stress using the mean temperature in the melt pool, indicating clear signature of composition. In this way, we have demonstrated that FLaSk dewetting as a rheology</div><div>method can be employed for high-throughput analysis of glassy thin film materials at high temperature and shear.</div>


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1951.2-1952
Author(s):  
S. Ugurlu ◽  
B. H. Egeli ◽  
A. Adrovic ◽  
K. Barut ◽  
S. Sahin ◽  
...  

Background:Pediatric to adult rheumatology transition can be a challenge for both the patient and the clinician, especially in rheumatology as it includes chronic diseases with close follow-up.Objectives:The objective of this study is to understand our tertiary rheumatology center patient demographic transitioning from pediatric to adult rheumatology in order to design prospective studies enhancing the evidence of transition recommendations.Methods:Patients included in this study are regularly followed-up in our adult rheumatology clinic and were regularly followed up in our pediatric rheumatology clinic in the past. They were all diagnosed with a rheumatologic condition receiving treatment. The patient files were assessed to have a better understanding of their demographic, disease and treatment information.Results:Our cohort includes 347 patients diagnosed with a variety of conditions that are Familial Mediterranean Fever (FMF) (n=216), Juvenile Idiopathic Arthritis (JIA) (n=56), Juvenile Spondyloarthritis (jSPA) (n=39), Systemic Lupus Erythematosus (SLE) (n=20), Behçet’s Disease (n=7) and the rest of the rheumatologic conditions with less than 5 patients each. The mean age of the patients during transition, mean age of diagnosis, and follow-up duration are 21.34±1.7, 10.4±4.18, and 10.82±4.4 in respective order. The treatment regimens the patients received are summarized in Table 1.Table 1.Current Treatment Information of the PatientsCurrent Treatment InformationDMARD26Colchicine23Adalimumab21Etanercept10NSAID4Tocilizumab3Cyclophosphamide3Rituximab2Prednisolone7Mycophenolate Mofetil1Canakinumab1Seven patients had FMF related attacks. In addition to attacks, one FMF patient had bilateral ankle pain and one patient had leg pain. One patient out of three diagnosed with Takayasu’s disease was still symptomatic. One patient had uveitis-related symptoms. One patient diagnosed with SLE had skin dryness. Furthermore, there were patients with sequelae formation. One patient diagnosed with oligoarticular JIA (oJIA) had bilateral hip sequela with the additional left hip prosthesis. One oJIA patient had micrognathia, and one had left knee sequela. One pJIA patient had small joint sequelae. One sJIA patient had bilateral hip sequelae. One jSPA patient had enthesopathy. One FMF patient had proteinuria due to amyloidosis formation. Another FMF patient had hip surgery due to sequela.Conclusion:Our center had patients with a variety of conditions with different natures of diseases. EULAR recommends the transition process to start no later than 14 years of age; however, this process started at the mean age of 21 in our patients. In most of these patients, especially the ones diagnosed with FMF, the control of disease activity was maintained. The transition of these different clinical entities might require certain amendments to the standard of care. For future references, we will be able to understand more about the adulthood prognosis of these clinical entities.Disclosure of Interests:None declared


2006 ◽  
Vol 20 (27) ◽  
pp. 1739-1747 ◽  
Author(s):  
QINGSONG LEI ◽  
ZHIMENG WU ◽  
XINHUA GENG ◽  
YING ZHAO ◽  
JIANPING XI

Hydrogenated silicon thin films (Si:H) have been deposited by using very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD). The structural, electrical and optical properties of the films were characterized. The transition process and the effect of pressure were studied. Results suggest that a narrow region, in which the transition from microcrystalline to amorphous growth takes place, exists in the regime of silane concentration (SC). This region is influenced by the working pressure (P). At lower pressure, the transition region is shifted to higher SC. Microcrystalline silicon (μ c-Si:H ) thin films deposited near transition region was applied as i-layer to the p-i-n solar cells. An efficiency of about 5.30% was obtained.


1997 ◽  
Vol 471 ◽  
Author(s):  
J. Liu ◽  
D. C. Morton ◽  
M. R. Miller ◽  
Y. Li ◽  
E. W. Forsythe ◽  
...  

ABSTRACTZn2SiO4:Mn thin films were deposited and studied as thin film phosphors for flat panel cathodoluminescent displays. Crystallized films with improved electrical conductivity were obtained after conventional and rapid thermal annealings in a N2 environment at 850Xy11100 °C for 0.25 to 60 minutes. A maximum cathodoluminescent efficiency of 1.3 Lm/W was achieved under dc excitation at 1500 volts. The luminescent emission from these thin films was peaked around 525 nm. The decay time of these films was controlled in the range of 2 to 10 ms by varying the deposition and annealing parameters. The fast response time of these thin films overcomes the long decay limitation of the Zn2SiO4:Mn powder phosphor in practical display applications.


2017 ◽  
Vol 13 (S337) ◽  
pp. 326-327
Author(s):  
Francesco Coti Zelati

AbstractWe present the results of a systematic study of all magnetar outbursts observed to date through a reanalysis of data acquired in about 1100 X-ray observations. We track the temporal evolution of the luminosity for all these events, model empirically their decays, and estimate the characteristic decay time-scales and the energy involved. We study the link between different parameters, and reveal several correlations between different quantities. We discuss our results in the framework of the models proposed to explain the triggering mechanism and evolution of magnetar outbursts.


2020 ◽  
Author(s):  
Antonio Corsello ◽  
Daniela Pugliese ◽  
Fiammetta Bracci ◽  
Daniela Knafelz ◽  
Bronislava Papadatou ◽  
...  

Abstract BackgroundTransition from pediatric to adult care of patients affected by Inflammatory Bowel Disease (IBD) is a critical step that needs specific care and multidisciplinary involvement. The aim of our study was to evaluate the outcome of the transition process of a cohort of IBD patients, exploring their readiness and the consequent impact on quality of life.MethodsThis observational study followed transitioned patients up for a minimum of 18 months after the beginning of transition process, from January 2014 to April 2019. Transition was carried-out through joint visits pediatricians and adult gastroenterologists. Clinical data before and after transition were collected. A subgroup of patients was submitted to an anonymous online questionnaire of 38 items drawn up based on the validated questionnaires TRAQ and SIBDQ within the first 6 months from the beginning of transition process.ResultsEighty-two patients with IBD were enrolled, with a mean age at transition of 20.2±2.7 years. Before transition, 40.2% of patients already had major surgery and 64.6% started biologics. At transition, 24% of patients were in moderate to severe active phase of their disease and 40% of them had already been treated with ≥ 2 biologics. The mean value of the TRAQ questionnaires was 3.4±0.5 and the mean score of SIBDQ was 53.9±9.8. A significant association was found between a TRAQ mean score > 3 and a SIBDQ > 50 (p=0.0129). Overall, 75% of patients had a positive opinion of the transition model adopted.ConclusionsA strong association has been found between TRAQ and SIBDQ questionnaires, showing how transition readiness has a direct impact on the quality of life of the young adult with IBD.


2001 ◽  
Vol 85 (5) ◽  
pp. 2063-2069 ◽  
Author(s):  
Kerstin Stenkamp ◽  
J. Matias Palva ◽  
Marylka Uusisaari ◽  
Sebastian Schuchmann ◽  
Dietmar Schmitz ◽  
...  

The decrease in brain CO2 partial pressure (pCO2) that takes place both during voluntary and during pathological hyperventilation is known to induce gross alterations in cortical functions that lead to subjective sensations and altered states of consciousness. The mechanisms that mediate the effects of the decrease in pCO2 at the neuronal network level are largely unexplored. In the present work, the modulation of gamma oscillations by hypocapnia was studied in rat hippocampal slices. Field potential oscillations were induced by the cholinergic agonist carbachol under an N-methyl-D-aspartate (NMDA)-receptor blockade and were recorded in the dendritic layer of the CA3 region with parallel measurements of changes in interstitial and intraneuronal pH (pHo and pHi, respectively). Hypocapnia from 5 to 1% CO2 led to a stable monophasic increase of 0.5 and 0.2 units in pHo and pHi, respectively. The mean oscillation frequency increased slightly but significantly from 32 to 34 Hz and the mean gamma-band amplitude (20 to 80 Hz) decreased by 20%. Hypocapnia induced a dramatic enhancement of the temporal stability of the oscillations, as was indicated by a two-fold increase in the exponential decay time constant fitted to the autocorrelogram. A rise in pHi evoked by the weak base trimethylamine (TriMA) was associated with a slight increase in oscillation frequency (37 to 39 Hz) and a decrease in amplitude (30%). Temporal stability, on the other hand, was decreased by TriMA, which suggests that its enhancement in 1% CO2 was related to the rise in pHo. In 1% CO2, the decay-time constant of the evoked monosynaptic pyramidal inhibitory postsynaptic current (IPSC) was unaltered but its amplitude was enhanced. This increase in IPSC amplitude seems to significantly contribute to the enhancement of temporal stability because the enhancement was almost fully reversed by a low concentration of bicuculline. These results suggest that changes in brain pCO2 can have a strong influence on the temporal modulation of gamma rhythms.


2019 ◽  
Vol 962 ◽  
pp. 41-48
Author(s):  
Tzong Daw Wu ◽  
Jiun Shen Chen ◽  
Ching Pei Tseng ◽  
Cheng Chang Hsieh

This study presents a real-time method for determining the thickness of each layer in multilayer thin films. Artificial neural networks (ANNs) were introduced to estimate thicknesses from a transmittance spectrum. After training via theoretical spectra which were generated by thin-film optics and modified by noise, ANNs were applied to estimate the thicknesses of four-layer nanoscale films which were TiO2, Ag, Ti, and TiO2 thin films assembled sequentially on polyethylene terephthalate (PET) substrates. The results reveal that the mean squared error of the estimation is 2.6 nm2, and is accurate enough to monitor film growth in real time.


1982 ◽  
Vol 37 (2) ◽  
pp. 197-198
Author(s):  
R. K. Bauer ◽  
R. Twardowski

Abstract The mean fluorescence decay time for rhodamine 6G (donor) in the presence of malachite green (acceptor) has been investigated using a pulse fluorometer. The experimental results have been compared with theoretical ones obtained earlier [1].


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