Crystals最新文献_第3页

Shape Dependence of Photoresponsive Molecular Crystals Composed of Naphthyl Acrylic Acid Stimulated by Solid-State [2 + 2] Photocycloaddition 固态 [2 + 2] 光环加成法激发的萘丙烯酸光致分子晶体的形状依赖性

Crystals Pub Date : 2024-05-23 DOI: 10.3390/cryst14060492

Tian-Yuan Li, Yu-Ze Du, Tian-Yi Xu, Tian-Le Zhang, Fei Tong

{"title":"Shape Dependence of Photoresponsive Molecular Crystals Composed of Naphthyl Acrylic Acid Stimulated by Solid-State [2 + 2] Photocycloaddition","authors":"Tian-Yuan Li, Yu-Ze Du, Tian-Yi Xu, Tian-Le Zhang, Fei Tong","doi":"10.3390/cryst14060492","DOIUrl":"https://doi.org/10.3390/cryst14060492","url":null,"abstract":"Photomechanical molecular crystals, actuated by solid-state photochemical reactions, manifest a spectrum of mechanical motions upon light exposure, underscoring their prospective integration into the next generation of intelligent materials and devices. Utilizing the solid-state photodimerization of naphthyl acrylic acid as a paradigm, this study delved into the interplay between crystal morphology and reaction dynamics on the photomechanical responses of molecular crystals. Distinct crystal forms—bulk, microrods, and microplates—were cultivated through tailored crystallization conditions. While bulk crystals of naphthyl acrylic acid (NA) underwent shattering and splintering upon UV light exposure, the microplate counterparts displayed unique cracking patterns with fissures yet retained their overall structural integrity. In contrast, NA microrods underwent pronounced bending under identical irradiation conditions. These phenomena are attributed to the efficient lattice reconfiguration stemming from the [2 + 2] cycloaddition photochemical reaction within the crystals. An intermediate fluorescence enhancement was observed across all crystal types upon light exposure. Collectively, our results underscore the pivotal role of crystal shape in dictating photomechanical behavior, thereby heralding novel strategies for developing advanced photomechanical materials.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107391","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}

引用次数: 0

Electrochemical Study and Mechanical Properties of Ti-Zr Alloy for Biomedical Applications 用于生物医学应用的钛锌合金的电化学研究和机械性能

Crystals Pub Date : 2024-05-23 DOI: 10.3390/cryst14060493

I. Hulka, I. Uțu, S. Brito-Garcia, A. Verdú-Vázquez, J. Mirza-Rosca

{"title":"Electrochemical Study and Mechanical Properties of Ti-Zr Alloy for Biomedical Applications","authors":"I. Hulka, I. Uțu, S. Brito-Garcia, A. Verdú-Vázquez, J. Mirza-Rosca","doi":"10.3390/cryst14060493","DOIUrl":"https://doi.org/10.3390/cryst14060493","url":null,"abstract":"In response to concerns of potential cytotoxicity and adverse tissue reactions caused by vanadium and aluminum in the currently used biomaterial Ti-6Al-4V, the Ti–20Zr alloy was evaluated in this study because it has been suggested as a candidate for human body implant material. The Ti-20Zr alloy was obtained by vacuum-melting, followed by heat treatment at 1000 °C for 1 h, and then air-cooled. Optical and scanning electron microscopy revealed that the sample had an α and β lamellar microstructure. Analysis showed that the mechanical properties, in terms of hardness measurements performed at low loads, were significantly different between the two phases. Thus, it was found out that the α phase is softer by about 30% compared to the β phase. The Electrochemical Impedance Spectroscopy technique (EIS) was employed to study the electrochemical behavior in simulated body fluid (SBF). The electrochemical behavior demonstrated that Ti-20Zr alloy exhibits excellent corrosion resistance due to the stable oxide layer formed on its surface. SEM and EDS investigations showed that the surface topography, after electrochemical studies, is characterized by a porous film with increased oxygen content, which might be suitable for the osteoinductive growth of bone.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"41 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107714","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}

引用次数: 0

Promoting Thermal Conductivity of Alumina-Based Composite Materials by Systematically Incorporating Modified Graphene Oxide 通过系统掺入改性氧化石墨烯提高氧化铝基复合材料的导热性能

Crystals Pub Date : 2024-05-23 DOI: 10.3390/cryst14060490

Nawon Lee, Jinsol Park, Nayeon Jang, Sehui Lee, Dayeon Kim, Sanggin Yun, Tae Woo Park, Jun-Hyun Kim, Hyun-Ho Park

{"title":"Promoting Thermal Conductivity of Alumina-Based Composite Materials by Systematically Incorporating Modified Graphene Oxide","authors":"Nawon Lee, Jinsol Park, Nayeon Jang, Sehui Lee, Dayeon Kim, Sanggin Yun, Tae Woo Park, Jun-Hyun Kim, Hyun-Ho Park","doi":"10.3390/cryst14060490","DOIUrl":"https://doi.org/10.3390/cryst14060490","url":null,"abstract":"Small amounts of thermally conductive graphene oxide (GO) and modified GO are systematically introduced as a second filler to thermal interface materials (TIMs) consisting of alumina (Al2O3) particles and polydimethylsiloxane (PDMS). The surface of GO is covalently linked with an organic moiety, octadecylamine (ODA), to significantly improve the miscibility and dispersity of GO across the TIM matrix. Subsequently, two series of PDMS-Al2O3 composite TIMs are manufactured as a function of GO and ODA-GO content (0.25 wt%–2.5 wt%) to understand the effect of these second additives. The incorporation of GO into the Al2O3-PDMS composite materials generally increases the thermal conductivity (TC), ranging from 18% to 29%. Conversely, the use of ODA-GO further enhances the overall performance of TIMs (22–54%) by facilitating the dispersion degree of GO across the composite matrix. The great improvement in TC is presumably related to the formation of conductive pathways by uniformly integrating 2D-type GO flakes across spherical Al2O3 particle networks. The ability to simply regulate the polarity of the thermally conductive second filler can provide an idea for designing cost-effective and practical TIM-2-type pads that can be commercially applicable in between an integrated heat spreader and a heat sink.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"27 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141105631","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}

引用次数: 0

Enhancing Photovoltaic Performance with BaTiO3/MWCNTs Composite Photoelectrodes in Dye-Sensitized Solar Cells 在染料敏化太阳能电池中使用 BaTiO3/MWCNTs 复合光电极提高光伏性能

Crystals Pub Date : 2024-05-23 DOI: 10.3390/cryst14060489

Carlos Armando Polo Bravo, Brayan Yeraldyn Caceres Osnayo, Jesús Alfredo Chacaltana García, Jesús Plácido Medina Salas, Francisco Gamarra Gómez, Hugo Alfredo Torres Muro, Alberto Bacilio Quispe Cohaila, R. Mangalaraja, Elisban Juani Sacari Sacari

{"title":"Enhancing Photovoltaic Performance with BaTiO3/MWCNTs Composite Photoelectrodes in Dye-Sensitized Solar Cells","authors":"Carlos Armando Polo Bravo, Brayan Yeraldyn Caceres Osnayo, Jesús Alfredo Chacaltana García, Jesús Plácido Medina Salas, Francisco Gamarra Gómez, Hugo Alfredo Torres Muro, Alberto Bacilio Quispe Cohaila, R. Mangalaraja, Elisban Juani Sacari Sacari","doi":"10.3390/cryst14060489","DOIUrl":"https://doi.org/10.3390/cryst14060489","url":null,"abstract":"Dye-sensitized solar cells (DSSCs) have attracted renewed research interest as a potential low-cost substitute for conventional silicon photovoltaics. This work aims to improve the photovoltaic performance of the DSSCs by incorporating multi-walled carbon nanotubes (MWCNTs) into the BaTiO3 photoelectrode. The pure BaTiO3 and BaTiO3/MWCNT nanocomposites were sensitized with N719 dye and fabricated into solar cell devices for testing. The structural characterization confirmed the successful formation of the nanocomposite with an optimal dispersion at 6% of MWCNT incorporation, beyond which agglomeration effects manifested. The optical analysis verified the modulation of defect states and bandgap engineering induced by the MWCNT network. The morphological studies revealed irregular nanoparticle clusters with embedded nanotubes. Solar cell testing under AM1.5G-simulated sunlight demonstrated a peak power conversion efficiency of 4.044% for 6% of MWCNT doping, constituting a 6-fold increment versus pure BaTiO3 (0.693%). It originated from the simultaneous enhancements in the open-circuit voltage and short-circuit current enabled by the favorable band structure alterations and percolation-assisted charge transport. However, further increasing MWCNT content deteriorated the device metrics, owing to emerging limitations like trapping. The rational integration of multi-walled carbon nanotubes with lead-free ferroelectric metal oxides can contribute to the development of emerging organic-inorganic hybrid solar platforms.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"14 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104776","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}

引用次数: 0

Wide Temperature Stability of BaTiO3-NaNbO3-Gd2O3 Dielectric Ceramics with Grain Core–Shell Structure 具有晶核壳结构的 BaTiO3-NaNbO3-Gd2O3 介电陶瓷的宽温稳定性

Crystals Pub Date : 2024-05-23 DOI: 10.3390/cryst14060488

Zicheng Zhao, Yaoning Bai, Mingwei Li, Huiming Ji

{"title":"Wide Temperature Stability of BaTiO3-NaNbO3-Gd2O3 Dielectric Ceramics with Grain Core–Shell Structure","authors":"Zicheng Zhao, Yaoning Bai, Mingwei Li, Huiming Ji","doi":"10.3390/cryst14060488","DOIUrl":"https://doi.org/10.3390/cryst14060488","url":null,"abstract":"As consumer electronics and industrial control systems continue to evolve, the operating temperature range of capacitors is gradually increasing. Barium titanate-based ceramic capacitors are widely used in the field of high dielectrics, so temperature-stable barium titanate-based dielectric materials have been a hot research topic in the field of dielectric ceramics. The construction of a core–shell structure by unequal doping is an effective way to obtain temperature-stable dielectric materials. At the same time, this structure retains part of the highly dielectric tetragonal phase, and materials with overall high dielectric constants can be obtained. In this work, we prepared BaTiO3-xNaNbO3-0.002Gd2O3 (x = 1.0–6.0 mol%) as well as BaTiO3-0.05NaNbO3-yGd2O3 (y = 0–0.30 mol%) dielectric ceramics. On the basis of high-electronic-bandgap NaNbO3-modified BaTiO3 dielectric ceramics, a core–shell structure with a larger proportion of core phase was obtained by further doping the amphiphilic rare-earth oxide Gd2O3. By designing this core–shell structure, the temperature stability range of capacitors can be expanded. At a doping level of 5.0 mol% NaNbO3 and 0.20 mol% Gd2O3, the room temperature dielectric constant εr = 4266 and dielectric loss tan δ = 0.95% conforms to the X8R standard (from −55 °C to 150 °C, TCC < ±15%); volume resistivity ρv = 10,200 GΩ·cm and breakdown strength Eb = 13.5 kV/mm is attained in BaTiO3-based ceramics. The system has excellent dielectric and insulating properties; it provides a new solution for temperature-stable dielectric ceramics.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"51 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107295","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}

引用次数: 0

Experimental and Modelling Research on the Effect of Prior Ferrite on Bainitic Transformation in Medium-Carbon Bainitic Steel 先铁素体对中碳贝氏体钢贝氏体转变影响的实验和模型研究

Crystals Pub Date : 2024-05-22 DOI: 10.3390/cryst14060487

Xinpan Yu, Wei Liu, Kang He, Tengfei Wang, G. Niu, Huibin Wu

引用次数: 0

Novel Quaternary Ammonium Aldimine Derivatives Featuring 3,4,5-Trimethoxy Phenyl Fragment: Synthesis, Crystal Structure and Evaluation of Antioxidant and Antibacterial Activity 含有 3,4,5-三甲氧基苯基片段的新型季铵醛亚胺衍生物：合成、晶体结构及抗氧化和抗菌活性评估

Crystals Pub Date : 2024-05-22 DOI: 10.3390/cryst14060486

R. Rusew, Mariya Georgieva, V. Kurteva, B. Shivachev

{"title":"Novel Quaternary Ammonium Aldimine Derivatives Featuring 3,4,5-Trimethoxy Phenyl Fragment: Synthesis, Crystal Structure and Evaluation of Antioxidant and Antibacterial Activity","authors":"R. Rusew, Mariya Georgieva, V. Kurteva, B. Shivachev","doi":"10.3390/cryst14060486","DOIUrl":"https://doi.org/10.3390/cryst14060486","url":null,"abstract":"This study demonstrates the synthesis of five novel quaternary ammonium aldimines through a two-step synthetic route involving a condensation reaction between 4-pyridincarboxyaldehyde and 3,4,5-trimethoxyaniline, followed by the quaternization of the pyridine N-atom with various aromatic α-bromo ketones. The newly obtained compounds underwent characterization for both purity and molecular structure, utilizing HR-MS, 1D, and 2D NMR spectroscopy in solution, as well as a comparison between single-crystal and powder X-ray analyses in a solid state. The thermal behavior of the studied compounds was evaluated using differential scanning calorimetry (DSC). The antioxidant properties of the compounds were assessed through DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and ferric-reducing antioxidant power (FRAP) assays, employing Trolox as a standard. The performed in vitro antibacterial screening indicates a selective antibacterial activity against Gram-negative K. pneumoniae and P. aeruginosa, while no such activity is detected for Gram-negative E. coli and Gram-positive S. aureus.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"1 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141108365","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}

引用次数: 0

Demonstration of HCl-Based Selective Wet Etching for N-Polar GaN with 42:1 Selectivity to Al0.24Ga0.76N 基于 HCl 的 N 极 GaN 选择性湿法蚀刻演示，对 Al0.24Ga0.76N 的选择性为 42:1

Crystals Pub Date : 2024-05-22 DOI: 10.3390/cryst14060485

Emmanuel Kayede, E. Akso, B. Romanczyk, N. Hatui, I. Sayed, Kamruzzaman Khan, H. Collins, S. Keller, Umesh K. Mishra

引用次数: 0

Enhanced Supercapacitor Performance by Harnessing Carbon Nanoparticles and Colloidal SnO2 Quantum Dots 利用碳纳米粒子和胶体二氧化锡量子点提高超级电容器性能

Crystals Pub Date : 2024-05-21 DOI: 10.3390/cryst14060482

T. T. Salunkhe, Babu Bathula, I. Kim, V. Thirumal, Kisoo Yoo

{"title":"Enhanced Supercapacitor Performance by Harnessing Carbon Nanoparticles and Colloidal SnO2 Quantum Dots","authors":"T. T. Salunkhe, Babu Bathula, I. Kim, V. Thirumal, Kisoo Yoo","doi":"10.3390/cryst14060482","DOIUrl":"https://doi.org/10.3390/cryst14060482","url":null,"abstract":"The creation of effective supercapacitor materials is still a priority in the quest to improve energy storage technology. Herein, we present a novel nanocomposite composed of carbon nanoparticles (CNPs) and colloidal SnO2 quantum dots (c-SQDs) or colloidal SnO2 ultrasmall nanoparticles, synthesized through a facile sonochemical-assisted hydrothermal approach. The XRD and XPS analyses confirmed the successful synthesis and composition of the CNP/c-SQD nanocomposite. Morphology studies revealed a well-dispersed morphology with intimate interfacial interactions between the CNPs and c-SQDs. Specifically, the nanocomposite exhibited a high specific capacitance of 569 F/g at a current density of 1 A/g, surpassing conventional carbon-based supercapacitors. Furthermore, the nanocomposite displayed excellent stability with 99% capacity retention after 5000 cycles, indicative of its superior cyclability. These results underscore the potential of the CNP/c-SQD nanocomposite as a promising electrode material for high-performance supercapacitor applications, offering enhanced charge storage capacity, stability, and cyclability. This study contributes to the advancement of energy storage technologies, paving the way for the development of efficient and sustainable electrochemical energy storage devices.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"35 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141117039","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}

引用次数: 0

Synthesis and Mechanism Study of Carbon Nanowires, Carbon Nanotubes, and Carbon Pompons on Single-Crystal Diamonds 单晶金刚石上碳纳米线、碳纳米管和碳绒球的合成与机理研究

Crystals Pub Date : 2024-05-21 DOI: 10.3390/cryst14060481

Shuai Wu, Qiang Wang, Kesheng Guo, Lei Liu, Jie Bai, Zhenhuai Yang, Xin Li, Hong Liu

{"title":"Synthesis and Mechanism Study of Carbon Nanowires, Carbon Nanotubes, and Carbon Pompons on Single-Crystal Diamonds","authors":"Shuai Wu, Qiang Wang, Kesheng Guo, Lei Liu, Jie Bai, Zhenhuai Yang, Xin Li, Hong Liu","doi":"10.3390/cryst14060481","DOIUrl":"https://doi.org/10.3390/cryst14060481","url":null,"abstract":"Carbon nanomaterials are in high demand owing to their exceptional physical and chemical properties. This study employed a mixture of CH4, H2, and N2 to create carbon nanostructures on a single-crystal diamond using microwave plasma chemical vapor deposition (MPCVD) under high-power conditions. By controlling the substrate surface and nitrogen flow rate, carbon nanowires, carbon nanotubes, and carbon pompons could be selectively deposited. The results obtained from OES, SEM, TEM, and Raman spectroscopy revealed that the nitrogen flow rate and substrate surface conditions were crucial for the growth of carbon nanostructures. The changes in the plasma shape enhanced the etching effect, promoting the growth of carbon pompons. The CN and C2 groups play vital catalytic roles in the formation of carbon nanotubes and nanowires, guiding the precipitation and composite growth of carbon atoms at the interface between the Mo metal catalysts and diamond. This study demonstrated that heterostructures of diamond–carbon nanomaterials could be produced under high-power conditions, offering a new approach to integrating diamond and carbon nanomaterials.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"52 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141118659","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}

引用次数: 0