Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.2
2.4
Journals
Crystals
Special Issues
Advanced Piezoelectric Crystals of Langasite Family
share announcement

Advanced Piezoelectric Crystals of Langasite Family

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystalline Materials".

Deadline for manuscript submissions: closed (30 June 2021) | Viewed by 8647

Special Issue Editor

Dr. Dmitry Roshchupkin

E-Mail Website
Guest Editor
Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Academician Ossipyan Str. 6, 142432 Chernogolovka, Russia
Interests: crystal growth; piezoelectric crystals; ferroelectric crystals; ferroelectric domain structure; X-ray diffraction; synchrotron radiation; crystal structure; crystal structure defects; surface acoustic waves; bulk acoustic waves

Special Issue Information

The development and search for new promising materials of the lanthanum–gallium silicate (LGS, La3Ga5SiO14) group with unique thermal properties are very important for progress in acoustoelectronics based on the application of surface and bulk acoustic waves. Crystals of the lanthanum–gallium silicate group belong to the 32 symmetry class-like crystals of SiO2 piezoquartz. In this group, several hundreds of crystals can be synthesized which can find application not only in acoustoelectronics but also in acoustooptics, optoelectronics, magnitooptics, and magnitoacoustics. Materials of this group possess high thermal stability.

The values of electromechanical coupling coefficients and piezoelectric constants of the LGS group, although lower than those of LiNbO3 crystals, exceed the corresponding values of quartz crystals by several fold. Note, also, that the interest in crystals of the langasite group is due to the absence of phase transitions in these crystals up to the melting temperature.

Currently, significant progress has been made in growing crystals up to 4 inches in diameter using the Czochralski method. At present, the issues of structural difference between ordered and disordered crystals of the LGS family remain open. The study of temperature dependences of both structural and physical properties, which is fundamentally important for various applications, including high-temperature sensors of physical quantities, is also important.

This Special Issue intends to collect and disseminate results in the synthesis and study of properties of LGS family crystals. We welcome publications on topics ranging from crystal growth to studies of structure, piezoelectric, optical, and acoustic properties. Publications related to applications of these crystals in sensors and acousto- and optoelectronics will also be of special importance.

We hope that this Special Issue of Crystals will bring gather the latest results, making them available to a large number of researchers.

Prof. Dr. Dmitry Roshchupkin
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • langasite
  • ordered and disordered crystals
  • crystal structure
  • piezoelectric modulus
  • surface and bulk acoustic waves
  • QCM
  • thermal stability

Published Papers (3 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

17 pages, 8438 KiB  
Article
Research on the Diffusion Behavior of Cu in Low-Carbon Steel under High Temperatures
by Huirong Li, Tao Ma, Yueying He and Yungang Li
Crystals 2022, 12(2), 207; https://doi.org/10.3390/cryst12020207 - 30 Jan 2022
Cited by 4 | Viewed by 2935
Abstract
The effective diffusion of Cu in Fe is the key to forming a stable transition layer between copper and low-carbon steel, but it is seriously affected by several factors, especially temperature, and the diffusion of Cu can only be completed at high temperatures. [...] Read more.
The effective diffusion of Cu in Fe is the key to forming a stable transition layer between copper and low-carbon steel, but it is seriously affected by several factors, especially temperature, and the diffusion of Cu can only be completed at high temperatures. In order to analyze the diffusion coefficient of Cu in low-carbon steel under high temperatures, and to obtain the best diffusion temperature range of Cu in steel, the electrodeposition method was used to prepare the diffusion couple of copper and low-carbon steel, which would be annealed under different temperatures for 6 h; meanwhile, the MD models were also used to analyze the diffusion behavior of Cu in Fe at different temperatures. The results show that the diffusion of Cu in low-carbon steel could be realized by high-temperature annealing, and as the temperature increases, the thickness of the Cu/low-carbon steel transition layer shows an increasing trend. When the annealing temperature is between 900 °C and 1000 °C, the thickness of the transition layer increases the fastest. The results of the MD models show that, when the temperature is in the phase transition zone, the main restrictive link for the diffusion of Cu in Fe is the phase transition process of Fe; additionally, when the temperature is higher, the main restrictive link for the diffusion of Cu in Fe is the activity of the atom. Full article
(This article belongs to the Special Issue Advanced Piezoelectric Crystals of Langasite Family)
►▼ Show Figures

Figure 1

16 pages, 3353 KiB  
Article
Remediation of Cd (II) Ion from an Aqueous Solution by a Starch-Based Activated Carbon: Experimental and Density Functional Theory (DFT) Approach
by Saad Melhi, Saeed Ullah Jan, Adnan Ali Khan, Khan Badshah, Saeed Ullah, Bushra Bostan and Zeliha Selamoglu
Crystals 2022, 12(2), 189; https://doi.org/10.3390/cryst12020189 - 27 Jan 2022
Cited by 8 | Viewed by 2947
Abstract
Heavy metal ion pollution is a serious threat for aquatic and terrestrial living beings. Adsorption is a facile process to encounter heavy metal pollution. Various types of adsorbents have been developed and used for environmental remediation. Activated carbon is one of the cheapest [...] Read more.
Heavy metal ion pollution is a serious threat for aquatic and terrestrial living beings. Adsorption is a facile process to encounter heavy metal pollution. Various types of adsorbents have been developed and used for environmental remediation. Activated carbon is one of the cheapest adsorbents derived from various biomass. In this work, the adsorption of cadmium ions (Cd (II)) with starch-based activated carbon (AC) having a specific surface area of 1600 m2 g−1 was investigated in a series of batch laboratory studies. The effective operating parameters, such as initial pH (pH0), initial concentration of metal ions, contact time, and temperature on the adsorption, were investigated. Validation of the kinetic study shows that the adsorption process is better predicted by the pseudo-second-order model. The extended Freundlich and Langmuir isotherms were applied to the study. The results show that the metal ion adsorption capacities of activated carbon increased with increasing pH, and it was found that maximum adsorption (284 mg g−1) of Cd (II) was achieved at pH solution of 5.5–6. The thermodynamic parameters, such as ∆G, ∆H, and ∆S, were found to be −17.42 kJ mol−1, 8.49 kJ mol−1, and 58.66 J mol−1 K−1, respectively, revealing that the adsorption mechanism is endothermic, spontaneous, and feasible. Furthermore, the density functional theory simulations demonstrated that the activated carbon strongly interacted with toxicity and mobility, so it is very urgent to remove this species from industrial wastewater before it is discharged into the environment. The adsorption energy calculated for all interactive sites was negative (−43.41 kJ mol−1 to −967.74 kJ mol−1), showing effective interaction between the adsorbate and adsorbent. The PDOS clearly shows that there is a stronger overlapping at the Femi level between the d orbital of the Cd ion and the p orbital of the O atom, showing a strong interaction and confirming the chemical bond formation between the Cd (II) ion and O atom. Full article
(This article belongs to the Special Issue Advanced Piezoelectric Crystals of Langasite Family)
►▼ Show Figures

Graphical abstract

14 pages, 4298 KiB  
Article
Influence of Culture Medium on Cementation of Coarse Grains Based on Microbially Induced Carbonate Precipitation
by Hong Gao and Shuhong Dai
Crystals 2022, 12(2), 188; https://doi.org/10.3390/cryst12020188 - 27 Jan 2022
Cited by 2 | Viewed by 2038
Abstract
A main challenge in the large-scale application of the microbially induced carbonate precipitation (MICP) technique includes the low efficiency of the cementation of coarse grains. Actually, in the MICP treatment process, the cementation effect of the bonding points was more important than pore [...] Read more.
A main challenge in the large-scale application of the microbially induced carbonate precipitation (MICP) technique includes the low efficiency of the cementation of coarse grains. Actually, in the MICP treatment process, the cementation effect of the bonding points was more important than pore filling due to the large porosity for coarse grains. To achieve a better cementation effect at bonding points between coarse particles, the quick formation and growth of a biofilm is necessary. In this study, an optimized medium was proposed to improve the cementation effects for coarse materials. The optimized medium and other different media were used for bio-cementation tests with MICP. The viable cell concentrations, strengths, microscopic characteristics, biofilm contents, and calcium carbonate (CaCO3) contents were used to evaluate the bio-cementation and its effects. In bio-cementation tests, the optimized medium led to increased CaCO3 precipitation at the bonding points and better cementation effects compared to other media. Indeed, the strength of the sample treated with the optimized medium was more than 1.2–4 times higher that of the values for other media. The advantages of the optimized medium were demonstrated via bio-cementation tests. Full article
(This article belongs to the Special Issue Advanced Piezoelectric Crystals of Langasite Family)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-3
Back to TopTop