Crystals最新文献

{"title":"The Effect of 147 MeV 84Kr and 24.5 MeV 14N Ions Irradiation on the Optical Absorption, Luminescence, Raman Spectra and Surface of BaFBr Crystals","authors":"A. Akilbekov, D. Kenbayev, A. Dauletbekova, Alexey Shalaev, A. Akylbekova, G. Aralbayeva, Z. Baimukhanov, M. Baizhumanov, E. Elsts, A. Popov","doi":"10.3390/cryst14060480","DOIUrl":"https://doi.org/10.3390/cryst14060480","url":null,"abstract":"Today, BaFBr crystals activated by europium ions are used as detectors that store absorbed energy in metastable centers. In these materials, the image created by X-ray irradiation remains stable in the dark for long periods at room temperature. As a result, memory image plates are created, and they are extended to other types of ionizing radiation as well. Despite significant progress towards X-ray storage and readout of information, the mechanisms of these processes have not been fully identified to date, which has hindered the efficiency of this class of phosphors. In this study, using photoluminescence (PL), optical absorption (OA), Raman spectroscopy (RS), and atomic force microscopy (AFM), the luminescence of oxygen vacancy defects to BaFBr crystals irradiated with 147 MeV 84Kr and 24.5 MeV 14N ions at 300 K to fluences (1010–1014) ion/cm2 was investigated. BaFBr crystals were grown by the Shteber method on a special device. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed the presence of Ba, Br, F, and O. The effect of oxygen impurities present in the studied crystals was considered. The analysis of the complex PL band, depending on the fluence and type of ions, showed the formation of three types of oxygen vacancy defects. Macrodefects (tracks) and aggregates significantly influence the luminescence of oxygen vacancy defects. The creation of hillocks and tracks in BaFBr crystals irradiated with 147 MeV 84Kr ions is shown for the first time. Raman spectra analysis confirmed that BaFBr crystals were amorphized by 147 MeV 84Kr ions due to track overlap, in contrast to samples irradiated with 24.5 MeV 14N ions. Raman and absorption spectra demonstrated the formation of hole and electron aggregate centers upon swift heavy ions irradiation.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"12 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141118461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystal Morphology Prediction Models and Regulating Methods","authors":"Yuan Gao, Wenxi Song, Jinyue Yang, Xiongtao Ji, Na Wang, Xin Huang, Ting Wang, Hongxun Hao","doi":"10.3390/cryst14060484","DOIUrl":"https://doi.org/10.3390/cryst14060484","url":null,"abstract":"Growing high-quality crystals with ideal properties is of great importance. The morphology of crystal is one key factor reflecting product quality, as it can affect the performance of products and downstream operations. In this work, the current state of crystal morphology modification is reviewed from different perspectives. First, the most widely used crystal growth models are discussed. Then, a variety of crystal morphology control methods, which include adjustment of crystallization operation parameters, addition of foreign molecules, change of different solvents, membrane assistance, the addition of external physical fields and the use of ball milling are summarized. As for applications, the control of crystal morphology has application potential in pharmaceutical and material fields, for example, energetic materials and semiconductor materials. Finally, the future development direction of crystal morphology regulation is discussed.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"126 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141115218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solid Forms and β-Cyclodextrin Complexation of Oxymetholone and Crystal Structure of Metribolone","authors":"Gheorghe Borodi, M. Miclăuş, M. Mureșan-Pop, A. Turza","doi":"10.3390/cryst14060483","DOIUrl":"https://doi.org/10.3390/cryst14060483","url":null,"abstract":"Oxymetholone [C21H32O3] and metribolone [C19H24O2] are synthetic anabolic-androgenic agents which are included in the steroid class. Their ability to form new solid forms and their possibility to be included in host–guest β-cyclodextrin complexes was explored. The recrystallization of the compounds in a wide variety of solvents was accomplished. Two oxymetholone polymorphs and one oxymetholone acetic acid solvate were obtained:, while metribolone is reported only in the starting form. Their crystal structures were elucidated using single-crystal X-ray diffraction and the energies of intermolecular interactions were analyzed. Moreover, oxymetholone also showed the ability to be complexed in a new form of oxymetholone–β-cyclodextrin complex. The materials were also investigated by powder X-ray diffraction, DSC/DTA/TGA analysis, and FT-IR spectroscopy.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"126 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141115227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-Performance Tandem White Micro-OLEDs for Virtual Reality and Mixed Reality Displays","authors":"Zhiyong Yang, En‐Lin Hsiang, Shin-Tson Wu","doi":"10.3390/cryst14040332","DOIUrl":"https://doi.org/10.3390/cryst14040332","url":null,"abstract":"To achieve wide-gamut and high-efficiency tandem white OLED (WOLED) microdisplays, we propose a new structure leveraging high-order antinodes and patterned microcavities. The color gamut coverages of 95% Rec. 2020 and 92% Rec. 2020 can be achieved in B/G/R tandem WOLED with a moderate microcavity and B/YG tandem WOLED with a strong microcavity, respectively. We have also boosted the optical efficiency by 62% for the tandem B/YG WOLED using the high-order antinodes at optimal conditions. Such a WOLED microdisplay helps reduce the power consumption of virtual reality (VR) and mixed reality (MR) displays while keeping a wide color gamut.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"6 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140359340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multimodal Spectroscopy Assays for Advanced Nano-Optics Approaches by Tuning Nano-Tool Surface Chemistry and Metal-Enhanced Fluorescence","authors":"Marcelo R. Romero, A. Veglia, M. Amé, A. Bracamonte","doi":"10.3390/cryst14040338","DOIUrl":"https://doi.org/10.3390/cryst14040338","url":null,"abstract":"In this research work, different chemical modifications were applied to gold nanoparticles and their use in enhanced non-classical light emitters based on metal-enhanced fluorescence (MEF) was evaluated. In order to achieve this, gold core–shell nanoparticles with silica shells were modified via multilayered addition and the incorporation of a covalently linked laser dye to develop MEF. Their inter-nanoparticle interactions were evaluated by using additional silica shell multilayers and modified cyclodextrin macrocycles. In this manner, the sizes and chemical surface interactions on the multilayered nanoarchitectures were varied. These optical active nanoplatforms led to the development of different nanoassembly sizes and luminescence behaviors. Therefore, the interactions and nanoassembly properties were evaluated by using various spectroscopic and nanoimaging techniques. Highly dispersible gold core–shell nanoparticles with diameters of 50–60 nm showed improved colloidal dispersion that led to single ultraluminescent gold core–shell nanoparticles with MEF. Then, the addition of variable silica lengths produced increased interactions and consequent nanoaggregation. However, the silanized nanoparticles were easily dispersible after agitation or sonication. Thus, their sizes were proportional only to the diameter and the van de Waals interaction did not affect their sizes in bulk. Then, the covalent linking of different concentrations of modified cyclodextrins was applied to the chemical surfaces by incorporating additional hydroxyl groups from the glucose monomeric unities of cyclodextrins. In this manner, variable larger-sized and inter-branched grafted gold core–shell silica nanoparticles were generated. The ultraluminescent properties were conserved due to the non-optical activity of the cyclodextrins. However, they generated enhanced ultraluminescence phenomena. Laser fluorescence microscopy nanoimaging showed enhanced resolutions in comparison to non-grafted supramolecular gold core–shell nanoparticles. The differences in their interactions and the sizes of the nanoassemblies were explained by their single nanoparticle diameters and the interacting chemical groups on their nanosurfaces. While the varied luminescence emissions generated were tuned by plasmonics, enhanced plasmonic phenomena and light scattering properties were seen depending on the type of nanoassembly. Thus, optically active and non-optically active materials led to different optical properties in the bright field and enhanced the excited state within the electromagnetic near-field of the gold nanotemplates. In this manner, it was possible to achieve high sensitivity by varying the spacer lengths and optical properties. Therefore, further perspectives regarding the design of nano-tools composed of light for various applications were discussed.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"16 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140359722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in New Functional Biomaterials for Medical Applications","authors":"M. Baltatu, P. Vizureanu, A. Sandu","doi":"10.3390/cryst14040334","DOIUrl":"https://doi.org/10.3390/cryst14040334","url":null,"abstract":"In this Special Issue entitled “Advances in New Functional Biomaterials for Medical Applications”, we present a remarkable compilation of research that spans the innovative landscape of biomaterials tailored to enhance medical treatments, diagnostics, and tissue engineering [...]","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"34 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140358383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Possibility of Using Secondary Alloys in the Production of Aluminum-Based Metal Matrix Composite","authors":"L. Lattanzi, A. Jarfors, S. Awe","doi":"10.3390/cryst14040333","DOIUrl":"https://doi.org/10.3390/cryst14040333","url":null,"abstract":"Aluminum-based composites provide tribological performance and thermophysical properties that, combined with being lightweight, are suitable for their application in automotive brake discs. Aluminum alloys allow the use of secondary materials to produce composites, with the drawback of several elements, impurities, and oxides that can harm the mechanical and thermophysical properties. This preliminary study explored the mechanical and thermophysical performance of a composite material produced with a secondary matrix alloy. Overall, the results are promising, with a minimal decrease in mechanical and thermophysical properties despite clustered silicon carbide particles in the composite with the secondary matrix. The challenges in effectively dispersing carbides in the melt seem linked to aluminum oxides, and future microstructural investigations will aim to clarify this aspect.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"30 33","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140358513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the Stability of Different Polar Surfaces in Aluminum Nitride Single Crystals","authors":"Zhao Liu, Wenliang Li, Zuoyan Qin, Lei Jin, Zhenhua Sun, Honglei Wu","doi":"10.3390/cryst14040337","DOIUrl":"https://doi.org/10.3390/cryst14040337","url":null,"abstract":"Wurtzite aluminum nitride (AlN) crystal has a non-centrosymmetric crystal structure with only a single axis of symmetry. In an AlN crystal, the electronegativity difference between the Al atom and N atom leads to a distortion of electron cloud distribution outside the nucleus and a spontaneous polarization (SP) along the c-axis direction. The N-polar surface along the directions of [000-1] has higher surface energy than the Al-polar surface along the directions of [0001]. Due to the different atomic arrangement, Al atoms on the Al-polar surface bond with O and OH− in the environment to generate Al2O3·xH2O, which prevents the reaction from occurring inside the crystal. After the Al2O3·xH2O dissolve in an alkaline environment, N atoms have three dangling bonds exposed on the surface, which can also protect OH− from destroying the internal Al-N bonds, so the Al-polar surface is more stable than the N-polar surface.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"12 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140358899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near-Infrared Spectroscopic Study of Biotite–Phlogopite (Mg# = 30~99): OH-Stretching Modes and Mg# Content Prediction Equation","authors":"Zhentao Yang, Mingyue He, Shaokun Wu, Mei Yang, Bijie Peng","doi":"10.3390/cryst14040336","DOIUrl":"https://doi.org/10.3390/cryst14040336","url":null,"abstract":"Biotite–phlogopite minerals are a complete Mg–Fe isomorphism series of phyllosilicates. A Fourier transform infrared spectroscopy (FTIR) and electron microprobe analysis (EMPA) were conducted on end-member phlogopite, Mg–biotite, and annite samples. In the mid-infrared region, absorption peaks were observed at 460, 1000, 3680, and 3710 cm⁻1 in the biotite group. Samples with higher Mg content exhibited stronger peaks assigned to OH vibrations and a weak absorption peak at 810 cm⁻1. In the near-infrared region, combination peaks were observed near 4200, 4300, and 4450 cm⁻1, with wavenumbers showing a linear inverse relationship with the Mg# [=100 × Mg/(Mg + FeT)] value. For annite, combination peaks occurred at 4173, 4292, and 4439 cm⁻1, decreasing by 10–15 cm⁻1 compared to end-member phlogopite. Judging the fundamental peaks of the combination band contributes to identifying suitable near-infrared characteristic peaks for quantitative research. The 4300 cm−1 absorption peak in biotite–phlogopite was assigned to OH-bending and -stretching vibrations, making it suitable for mineral identification and Mg# estimations across all biotite groups. The 4450 cm-1 characteristic peak, assigned to Al–O-stretching vibrations and OH-stretching vibrations, is suitable for accurately predicting Mg# values in high AlVI samples. The first overtones of biotite–phlogopite appeared at 7250 cm⁻1, with an average factor of 1.955 between the fundamental and corresponding overtones. This study aims to refine the patterns of OH-stretching vibrations and characteristic peak shifts in the near-infrared spectral region of phyllosilicate minerals, providing data references for planetary spectroscopy and ore deposit studies.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"30 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140360676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Exothermic Additions in Core Filler on Arc Stability and Microstructure during Self-Shielded, Flux-Cored Arc Welding","authors":"V. Lozynskyi, Bohdan Trembach, Egidijus Katinas, Kostiantyn Sadovyi, M. Krbaťa, Oleksii Balenko, Ihor Krasnoshapka, Olena Rebrova, Sergey Knyazev, Oleksii Kabatskyi, Hanna Kniazieva, L. Ropyak","doi":"10.3390/cryst14040335","DOIUrl":"https://doi.org/10.3390/cryst14040335","url":null,"abstract":"In the conditions of an energy crisis, an important issue is the increase in energy efficiency and productivity of welding and hardfacing processes. The article substantiates the perspective of using exothermic additives introduced into core filler for flux-cored wire arc welding processes as a relatively cheap additional heat source, reducing energy consumption when melting filler materials, and increasing the deposition rate. The mixture design (MD) was selected as the design method to optimize the average values of current and voltage, as well as arc stability parameters depending on core filler composition. This article studies the influence of the introduction of exothermic addition (EA), as well as the ratios CuO/C and CuO/Al on arc stability for the FCAW S process. Parameters characterizing arc stability were determined using an oscillograph, and from the obtained oscillograms, an analysis was conducted on arc voltage and welding current signals during flux-cored arc welding. It was determined that various methods can be used to evaluate arc stability, which can be divided into two groups: graphical (current and voltage cyclograms, box plots with frequency histograms, ellipse parameters plotted on current, and voltage cyclograms) and statistical (standard variation and coefficients of variation for welding current and arc voltage). In this paper, a comprehensive evaluation of arc stability depending on the composition of the cored wire filler was carried out. It was determined that the most stable current parameters were observed for the flux-cored wire electrode with an average exothermic addition content at the level of EA = 26.5–28.58 wt.% and a high carbon content (low values of CuO/C = 3.75). Conversely, the lowest values of arc stability (CV(U) and Std(U)) were observed during hardfacing with a flux-cored wire electrode with a high CuO/Al ratio ≥ 4.5 and a content of exothermic addition in the core filler below the average EA < 29 wt.%. Mathematical models of mean values, standard deviation, coefficient of variation for welding current, and arc voltage were developed. The results indicated that the response surface prediction models had good accuracy and prediction ability. The developed mathematical models showed that the ratio of oxidizing agent to reducing agent in the composition of exothermic addition (CuO/Al) had the greatest influence on the welding current and arc voltage characteristics under investigation. The percentage of exothermic mixture in the core filler (EA) only affected the average welding current (Iaw) and the average arc voltage (Uaw). The graphite content expressed through the CuO/C ratio had a significant impact on welding current parameters as well as the coefficient of variation of arc voltage (CV(U)). Two welding parameters were selected for optimization: the mean welding current (Iaw) and the standard deviation of arc voltage (Std(U)). The best arc stability when using exothermic addition CuO-Al in the cor","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"27 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140360764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}