A stochastic model, simulation, and application to aggregation of cadmium sulfide nanocrystals upon evaporation of the Langmuir–Blodgett matrix

Abstract A stochastic model of nanocrystals clusters formation is developed and applied to simulate an aggregation of cadmium sulfide nanocrystals upon evaporation of the Langmuir–Blodgett matrix. Simulations are compared with our experimental results. The stochastic model suggested governs mobilities both of individual nanocrystals and its clusters (arrays). We give a comprehensive analysis of the patterns simulated by the model, and study an influence of the surrounding medium (solvent) on the aggregation processes. In our model, monomers have a finite probability of separation from the cluster which depends on the temperature and binding energy between nanocrystals, and can also be redistributed in the composition of the cluster, leading to its compaction. The simulation results obtained in this work are compared with the experimental data on the aggregation of CdS nanocrystals upon evaporation of the Langmuir–Blodgett matrix. This system is a typical example from real life and is noteworthy in that the morphology of nanocrystals after evaporation of the matrix cannot be described exactly by a model based only on the motion of individual nanocrystals or by a cluster-cluster aggregation model.

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Photoluminescence from cadmium sulfide nanoclusters formed in the matrix of a Langmuir-Blodgett film

Semiconductors ◽

10.1134/1.1626217 ◽

2003 ◽

Vol 37 (11) ◽

pp. 1321-1325 ◽

Cited By ~ 15

Author(s):

E. A. Bagaev ◽

K. S. Zhuravlev ◽

L. L. Sveshnikova ◽

I. A. Badmaeva ◽

S. M. Repinskii ◽

...

Keyword(s):

Cadmium Sulfide ◽

Blodgett Film ◽

Langmuir Blodgett ◽

The Matrix ◽

Langmuir Blodgett Film

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IMPURITY INFLUENCE OF THE MATRIX SOLUTION ON THE SIZE OF CADMIUM SULFIDE NANOCRYSTALS, SYNTHESIZED BY SOL-GEL TECHNOLOGY

Sensor Electronics and Microsystem Technologies ◽

10.18524/1815-7459.2008.3.114998 ◽

2008 ◽

Vol 5 (3) ◽

pp. 69-73

Author(s):

V. A. Smyntyna ◽

V. M. Skobeeva ◽

T. F. Zavezion

Keyword(s):

Cadmium Sulfide ◽

Sol Gel ◽

Matrix Solution ◽

The Matrix ◽

Sulfide Nanocrystals

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The Effect of Chemical Composition and Electrolyte Temperature on the Size and Structure of Cadmium Sulfide Nanocrystals Obtained by the Electrolytic Method

Journal of Nano- and Electronic Physics ◽

10.21272/jnep.12(4).04035 ◽

2020 ◽

Vol 12 (4) ◽

pp. 04035-1-04035-6

Author(s):

N. B. Danilevska ◽

◽

M. V. Moroz ◽

B. D. Nechyporuk ◽

S. H. Haievska ◽

...

Keyword(s):

Chemical Composition ◽

Cadmium Sulfide ◽

Electrolyte Temperature ◽

Size And Structure ◽

Sulfide Nanocrystals

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Tunable characteristics of low-frequency bandgaps in two-dimensional multivibrator phononic crystal plates under prestrain

Scientific Reports ◽

10.1038/s41598-021-87904-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hai-Fei Zhu ◽

Xiao-Wei Sun ◽

Ting Song ◽

Xiao-Dong Wen ◽

Xi-Xuan Liu ◽

...

Keyword(s):

Phononic Crystal ◽

Real Life ◽

Low Frequency ◽

Acoustic Vibration ◽

Crystal Plate ◽

Frequency Noise ◽

Two Dimensional ◽

The Matrix ◽

Noise Frequency ◽

Realtime Control

AbstractIn view of the influence of variability of low-frequency noise frequency on noise prevention in real life, we present a novel two-dimensional tunable phononic crystal plate which is consisted of lead columns deposited in a silicone rubber plate with periodic holes and calculate its bandgap characteristics by finite element method. The low-frequency bandgap mechanism of the designed model is discussed simultaneously. Accordingly, the influence of geometric parameters of the phononic crystal plate on the bandgap characteristics is analyzed and the bandgap adjustability under prestretch strain is further studied. Results show that the new designed phononic crystal plate has lower bandgap starting frequency and wider bandwidth than the traditional single-sided structure, which is due to the coupling between the resonance mode of the scatterer and the long traveling wave in the matrix with the introduction of periodic holes. Applying prestretch strain to the matrix can realize active realtime control of low-frequency bandgap under slight deformation and broaden the low-frequency bandgap, which can be explained as the multiple bands tend to be flattened due to the localization degree of unit cell vibration increases with the rise of prestrain. The presented structure improves the realtime adjustability of sound isolation and vibration reduction frequency for phononic crystal in complex acoustic vibration environments.

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Estimating the number of usability problems affecting medical devices: modelling the discovery matrix

BMC Medical Research Methodology ◽

10.1186/s12874-020-01091-y ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Vincent Vandewalle ◽

Alexandre Caron ◽

Coralie Delettrez ◽

Renaud Périchon ◽

Sylvia Pelayo ◽

...

Keyword(s):

Medical Devices ◽

Market Access ◽

Real Life ◽

Usability Testing ◽

Probability Of Detection ◽

Usability Problems ◽

Usability Problem ◽

Wide Range ◽

The Matrix ◽

Problem Detection

Abstract Background Usability testing of medical devices are mandatory for market access. The testings’ goal is to identify usability problems that could cause harm to the user or limit the device’s effectiveness. In practice, human factor engineers study participants under actual conditions of use and list the problems encountered. This results in a binary discovery matrix in which each row corresponds to a participant, and each column corresponds to a usability problem. One of the main challenges in usability testing is estimating the total number of problems, in order to assess the completeness of the discovery process. Today’s margin-based methods fit the column sums to a binomial model of problem detection. However, the discovery matrix actually observed is truncated because of undiscovered problems, which corresponds to fitting the marginal sums without the zeros. Margin-based methods fail to overcome the bias related to truncation of the matrix. The objective of the present study was to develop and test a matrix-based method for estimating the total number of usability problems. Methods The matrix-based model was based on the full discovery matrix (including unobserved columns) and not solely on a summary of the data (e.g. the margins). This model also circumvents a drawback of margin-based methods by simultaneously estimating the model’s parameters and the total number of problems. Furthermore, the matrix-based method takes account of a heterogeneous probability of detection, which reflects a real-life setting. As suggested in the usability literature, we assumed that the probability of detection had a logit-normal distribution. Results We assessed the matrix-based method’s performance in a range of settings reflecting real-life usability testing and with heterogeneous probabilities of problem detection. In our simulations, the matrix-based method improved the estimation of the number of problems (in terms of bias, consistency, and coverage probability) in a wide range of settings. We also applied our method to five real datasets from usability testing. Conclusions Estimation models (and particularly matrix-based models) are of value in estimating and monitoring the detection process during usability testing. Matrix-based models have a solid mathematical grounding and, with a view to facilitating the decision-making process for both regulators and device manufacturers, should be incorporated into current standards.

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The effect of solvent on the crystal structure and size distribution of cadmium sulfide nanocrystals

Physica E Low-dimensional Systems and Nanostructures ◽

10.1016/j.physe.2008.02.011 ◽

2008 ◽

Vol 40 (9) ◽

pp. 2894-2898 ◽

Cited By ~ 11

Author(s):

R. Lotfi Orimi ◽

N. Shahtahmasebi ◽

N. Tajabor ◽

A. Kompany

Keyword(s):

Crystal Structure ◽

Cadmium Sulfide ◽

Size Distribution ◽

Effect Of Solvent ◽

Sulfide Nanocrystals

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A Numerical Approach for Evaluating the Time-Dependent Distribution of a Quasi Birth-Death Process

Methodology And Computing In Applied Probability ◽

10.1007/s11009-021-09882-6 ◽

2021 ◽

Author(s):

Michel Mandjes ◽

Birgit Sollie

Keyword(s):

Continuous Time ◽

Real Life ◽

Numerical Approach ◽

Time Dependent ◽

Death Process ◽

Continuous Time Markov Chain ◽

Likelihood Estimator ◽

Real Life Data ◽

The Matrix ◽

Birth Death

AbstractThis paper considers a continuous-time quasi birth-death (qbd) process, which informally can be seen as a birth-death process of which the parameters are modulated by an external continuous-time Markov chain. The aim is to numerically approximate the time-dependent distribution of the resulting bivariate Markov process in an accurate and efficient way. An approach based on the Erlangization principle is proposed and formally justified. Its performance is investigated and compared with two existing approaches: one based on numerical evaluation of the matrix exponential underlying the qbd process, and one based on the uniformization technique. It is shown that in many settings the approach based on Erlangization is faster than the other approaches, while still being highly accurate. In the last part of the paper, we demonstrate the use of the developed technique in the context of the evaluation of the likelihood pertaining to a time series, which can then be optimized over its parameters to obtain the maximum likelihood estimator. More specifically, through a series of examples with simulated and real-life data, we show how it can be deployed in model selection problems that involve the choice between a qbd and its non-modulated counterpart.

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