Local droplet-etched-based GaAs quantum dots are promising candidates for high-quality single and entangled photon sources. They have excellent optical and spin properties thanks to their size, shape and nearly strain-free matrix integration. In this study, we investigate the onset of aluminum nanodroplet formation for the local droplet etching process. Using molecular beam epitaxy, we grew several local droplet-etched quantum dot samples with different arsenic beam equivalent pressures. In each sample, we varied the etch material amount using a gradient technique and filled the nanoholes with GaAs to form optically active quantum dots after overgrowth. We repeated the local droplet etching process without the filling process, enabling us to characterize surface nanoholes with atomic force microscopy and compare them with photoluminescence from the buried quantum dots. We found a linear dependency on the arsenic beam-equivalent pressures for a critical aluminum amount necessary for nanohole formation and analyzed shape, density and optical properties close to this transition.
{"title":"Critical Aluminum Etch Material Amount for Local Droplet-Etched Nanohole-Based GaAs Quantum Dots","authors":"Timo Kruck, H. Babin, A. Wieck, A. Ludwig","doi":"10.3390/cryst14080714","DOIUrl":"https://doi.org/10.3390/cryst14080714","url":null,"abstract":"Local droplet-etched-based GaAs quantum dots are promising candidates for high-quality single and entangled photon sources. They have excellent optical and spin properties thanks to their size, shape and nearly strain-free matrix integration. In this study, we investigate the onset of aluminum nanodroplet formation for the local droplet etching process. Using molecular beam epitaxy, we grew several local droplet-etched quantum dot samples with different arsenic beam equivalent pressures. In each sample, we varied the etch material amount using a gradient technique and filled the nanoholes with GaAs to form optically active quantum dots after overgrowth. We repeated the local droplet etching process without the filling process, enabling us to characterize surface nanoholes with atomic force microscopy and compare them with photoluminescence from the buried quantum dots. We found a linear dependency on the arsenic beam-equivalent pressures for a critical aluminum amount necessary for nanohole formation and analyzed shape, density and optical properties close to this transition.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"32 40","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924959","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}
Yi Jiang, Jiafeng Wu, Chao Zhou, Qingqing Han, Chunjian Hua
The lap welding process for 304L stainless steel welded using the pulsed gas tungsten arc welding (P-GTAW) procedure was studied, and the effects of the pulse welding parameters (the peak current, background current, duty cycle, pulse frequency, and welding speed) on the macroscopic morphology, microstructure, and mechanical properties of the resultant lap joints were investigated. Tensile tests, hardness measurements, and SEM/EDS/XRD analyses were conducted to reveal the characterization of the joint. The relationships between the welding parameters; certain joint characteristic dimensions (the weld width, D; the weld width on the lower plate, La; the weld depth on the lower plate, P; and the minimum fusion radius, R); and the maximum tensile bearing capacity were studied. The weld zone was primarily composed of vermicular ferrite, skeletal ferrite, and austenite, and no obvious welding defects, precipitation, or phase transformations were evident in the weld. Microhardness tests demonstrated that the weld microhardness was highest in the base metal zone and lowest in the weld zone. As the heat input increased, the average microhardness decreased. The hardness difference reached 17.6 Hv10 due to the uneven grain size and the transformation of the structure to ferrite in the weld. The fracture location in welded joints varied as the heat input changed. In some parameter combinations, the weld tensile strength was significantly higher than that of the base material, with fractures occurring in the weld. Scanning electron microscopy results exhibited an obvious dimple morphology, which is a typical form of ductile fracture. XRD revealed no significant phase changes in the weld zone, with a higher intensity of the austenite diffraction peaks compared to the ferrite diffraction peaks.
{"title":"Study on Pulsed Gas Tungsten Arc Lap Welding Techniques for 304L Austenitic Stainless Steel","authors":"Yi Jiang, Jiafeng Wu, Chao Zhou, Qingqing Han, Chunjian Hua","doi":"10.3390/cryst14080715","DOIUrl":"https://doi.org/10.3390/cryst14080715","url":null,"abstract":"The lap welding process for 304L stainless steel welded using the pulsed gas tungsten arc welding (P-GTAW) procedure was studied, and the effects of the pulse welding parameters (the peak current, background current, duty cycle, pulse frequency, and welding speed) on the macroscopic morphology, microstructure, and mechanical properties of the resultant lap joints were investigated. Tensile tests, hardness measurements, and SEM/EDS/XRD analyses were conducted to reveal the characterization of the joint. The relationships between the welding parameters; certain joint characteristic dimensions (the weld width, D; the weld width on the lower plate, La; the weld depth on the lower plate, P; and the minimum fusion radius, R); and the maximum tensile bearing capacity were studied. The weld zone was primarily composed of vermicular ferrite, skeletal ferrite, and austenite, and no obvious welding defects, precipitation, or phase transformations were evident in the weld. Microhardness tests demonstrated that the weld microhardness was highest in the base metal zone and lowest in the weld zone. As the heat input increased, the average microhardness decreased. The hardness difference reached 17.6 Hv10 due to the uneven grain size and the transformation of the structure to ferrite in the weld. The fracture location in welded joints varied as the heat input changed. In some parameter combinations, the weld tensile strength was significantly higher than that of the base material, with fractures occurring in the weld. Scanning electron microscopy results exhibited an obvious dimple morphology, which is a typical form of ductile fracture. XRD revealed no significant phase changes in the weld zone, with a higher intensity of the austenite diffraction peaks compared to the ferrite diffraction peaks.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"38 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923051","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}
Metasurfaces are considered the most promising technologies for holographic imaging applications due to their exceptional optical properties and capabilities. However, the work on terahertz (THz) metasurface holographic imaging is relatively limited. Here, we propose a THz dielectric geometric-propagation phase metasurface that can operate in dual modes (reflection and transmission) and enable reconfigurable multifunctional holographic imaging. The dual-mode operation is realized by controlling the Fermi energy level (Ef) of the graphene integrated into the metasurface unit, and the reconfigurable three-channel holographic imaging in reflection or transmission mode are achieved by switching the feed polarization among left-handed circular polarization (LCP), right-handed circular polarization (RCP), and linear polarization (LP). The metasurface is designed based on the transmission mode, and a physical model for switching to the reflection mode is established. For the first time, to the best of our knowledge, a reflection–transmission dynamic modulation THz holographic imaging metasurface has been developed. The holographic metasurface operates in transmission mode at Ef = 0.1 eV and in reflection mode at Ef = 0.9 eV. Compared with recently published holographic imaging metasurfaces, the proposed metasurface offers the following advantages: high holographic efficiencies (42.5% to 49%), more holographic imaging channels, dynamic modulation dual-mode operations, and reconfigurability. The simulation results match the theory.
超表面因其卓越的光学特性和功能，被认为是最有前景的全息成像应用技术。然而，有关太赫兹（THz）元表面全息成像的研究相对有限。在这里，我们提出了一种太赫兹介质几何传播相元表面，它可以在双模式（反射和透射）下工作，实现可重构的多功能全息成像。通过控制集成到元表面单元中的石墨烯的费米能级（Ef）实现双模运行，并通过在左手圆极化（LCP）、右手圆极化（RCP）和线性极化（LP）之间切换馈电极化，实现反射或透射模式下的可重构三通道全息成像。根据透射模式设计了元表面，并建立了切换到反射模式的物理模型。据我们所知，这是首次开发出反射-透射动态调制太赫兹全息成像元表面。该全息元表面在 Ef = 0.1 eV 时以透射模式工作，在 Ef = 0.9 eV 时以反射模式工作。与最近发表的全息成像元表面相比，所提出的元表面具有以下优势：高全息效率（42.5% 至 49%）、更多全息成像通道、动态调制双模式操作和可重构性。仿真结果与理论相符。
{"title":"Terahertz Dielectric Metasurface for Reconfigurable Multifunctional Holographic Dual-Mode Imaging Controlled by Graphene","authors":"Hui-Fen Huang, Jian-Yuan Wang","doi":"10.3390/cryst14080713","DOIUrl":"https://doi.org/10.3390/cryst14080713","url":null,"abstract":"Metasurfaces are considered the most promising technologies for holographic imaging applications due to their exceptional optical properties and capabilities. However, the work on terahertz (THz) metasurface holographic imaging is relatively limited. Here, we propose a THz dielectric geometric-propagation phase metasurface that can operate in dual modes (reflection and transmission) and enable reconfigurable multifunctional holographic imaging. The dual-mode operation is realized by controlling the Fermi energy level (Ef) of the graphene integrated into the metasurface unit, and the reconfigurable three-channel holographic imaging in reflection or transmission mode are achieved by switching the feed polarization among left-handed circular polarization (LCP), right-handed circular polarization (RCP), and linear polarization (LP). The metasurface is designed based on the transmission mode, and a physical model for switching to the reflection mode is established. For the first time, to the best of our knowledge, a reflection–transmission dynamic modulation THz holographic imaging metasurface has been developed. The holographic metasurface operates in transmission mode at Ef = 0.1 eV and in reflection mode at Ef = 0.9 eV. Compared with recently published holographic imaging metasurfaces, the proposed metasurface offers the following advantages: high holographic efficiencies (42.5% to 49%), more holographic imaging channels, dynamic modulation dual-mode operations, and reconfigurability. The simulation results match the theory.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"113 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926454","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}
Omar Alageel, N. Alfrisany, Abdullah Aldosari, Saud Qashish, Majed M. Alsarani, A. Alfaify
Titanium-based dental prostheses are essential for prosthodontics and can now be 3D printed using powder bed fusion (PBF) technology with different densities by controlling the process parameters. This study aimed to assess the surface topography and bonding strength of dental resins made of 3D-printed titanium alloys with varying densities and growth directions. Three groups of titanium alloy (Ti6Al4V) specimens differentiated by density (low, medium, and high) were produced using laser-melting 3D printing technology (N = 8). Each group included specimen surfaces with vertical and horizontal growths. Vickers microhardness, surface profilometry, wettability, and shear bond strength (SBS) of the titanium samples were measured for all groups. Scanning electron microscopy (SEM) was performed. Statistical analyses were conducted using a two-way ANOVA and Fisher’s multiple test. Higher-density specimens exhibited greater microhardness (p < 0.05), and those with horizontal growth directions were harder (p < 0.05) than their vertical counterparts within the same density category. Additionally, low-density specimens in both growth directions had the highest surface roughness values (p < 0.05) compared to the other groups. The wettability values were similar (p > 0.05) among the groups in the vertical direction, but not in the horizontal direction (p < 0.05). However, the density type did not significantly (p > 0.05) influence the bonding strength of 3D-printed titanium. This study revealed significant variations in surface roughness, contact angle, and microhardness based on density and growth direction.
钛基义齿是口腔修复学中必不可少的材料，现在可以通过控制工艺参数，使用粉末床融合（PBF）技术三维打印出不同密度的钛基义齿。本研究旨在评估由不同密度和生长方向的 3D 打印钛合金制成的牙科树脂的表面形貌和粘接强度。采用激光熔融三维打印技术制作了三组不同密度（低、中、高）的钛合金（Ti6Al4V）试样（N = 8）。每组包括垂直和水平生长的试样表面。测量了所有组钛样品的维氏硬度、表面粗糙度、润湿性和剪切结合强度（SBS）。还进行了扫描电子显微镜（SEM）检查。使用双向方差分析和费雪多重检验进行了统计分析。密度较高的试样显示出更高的显微硬度（p < 0.05），在同一密度类别中，水平生长方向的试样比垂直生长方向的试样更硬（p < 0.05）。此外，与其他组别相比，两个生长方向的低密度试样的表面粗糙度值最高（p < 0.05）。各组的润湿性值在垂直方向上相似（p > 0.05），但在水平方向上不相似（p < 0.05）。然而，密度类型对 3D 打印钛的粘接强度没有显著影响（p > 0.05）。本研究揭示了基于密度和生长方向的表面粗糙度、接触角和显微硬度的显著差异。
{"title":"Impact of Density Variations and Growth Direction in 3D-Printed Titanium Alloys on Surface Topography and Bonding Performance with Dental Resins","authors":"Omar Alageel, N. Alfrisany, Abdullah Aldosari, Saud Qashish, Majed M. Alsarani, A. Alfaify","doi":"10.3390/cryst14080712","DOIUrl":"https://doi.org/10.3390/cryst14080712","url":null,"abstract":"Titanium-based dental prostheses are essential for prosthodontics and can now be 3D printed using powder bed fusion (PBF) technology with different densities by controlling the process parameters. This study aimed to assess the surface topography and bonding strength of dental resins made of 3D-printed titanium alloys with varying densities and growth directions. Three groups of titanium alloy (Ti6Al4V) specimens differentiated by density (low, medium, and high) were produced using laser-melting 3D printing technology (N = 8). Each group included specimen surfaces with vertical and horizontal growths. Vickers microhardness, surface profilometry, wettability, and shear bond strength (SBS) of the titanium samples were measured for all groups. Scanning electron microscopy (SEM) was performed. Statistical analyses were conducted using a two-way ANOVA and Fisher’s multiple test. Higher-density specimens exhibited greater microhardness (p < 0.05), and those with horizontal growth directions were harder (p < 0.05) than their vertical counterparts within the same density category. Additionally, low-density specimens in both growth directions had the highest surface roughness values (p < 0.05) compared to the other groups. The wettability values were similar (p > 0.05) among the groups in the vertical direction, but not in the horizontal direction (p < 0.05). However, the density type did not significantly (p > 0.05) influence the bonding strength of 3D-printed titanium. This study revealed significant variations in surface roughness, contact angle, and microhardness based on density and growth direction.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"100 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926735","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}
Yuting Tao, Shaohua Jin, Tongbin Wang, Chongchong She, Kun Chen, Junfeng Wang, Lijie Li
The cocrystallization of 1,3,5,7-tetranitro-1,3,5,7-tetrazolidine (HMX) with cyclopentanone was achieved via a controlled cooling method, followed by comprehensive characterization that confirmed the α-configuration of HMX within the cocrystal. The enthalpy of dissolution of HMX in cyclopentanone was assessed across a range of temperatures using a C-80 Calvert microcalorimeter, revealing an endothermic dissolution process. Subsequently, the molar enthalpy of dissolution was determined, and kinetic equations describing the dissolution rate were derived for temperatures of 303.15, 308.15, 313.15, 318.15, and 323.15 K as follows: dα⁄dt = 10−2.46(1 − α)0.35, dα⁄dt = 10−2.19(1 − α)0.79, dα⁄dt = 10−1.76(1 − α)1.32, dα⁄dt = 10−1.86(1 − α)0.46, and dα⁄dt = 10−2.02(1 − α)0.70, respectively. Additionally, molecular dynamics (MD) simulations investigated the intermolecular interactions of the HMX/cyclopentanone cocrystallization process, demonstrating a transformation of HMX from β- to α-conformation within the cyclopentanone environment. Theoretical calculations performed at the ωB97XD/6-311G(d,p) level affirmed that α-HMX exhibited stronger binding affinity toward cyclopentanone compared to β-HMX, corroborating experimental findings. A comprehensive understanding of the dissolution behavior of HMX in cyclopentanone holds significant implications for crystal growth methodologies and cocrystallization processes. Such insights are pivotal for optimizing HMX dissolution processes and offer valuable perspectives for developing and designing advanced energetic materials.
{"title":"Preparation, Thermal Behavior, and Conformational Stability of HMX/Cyclopentanone Cocrystallization","authors":"Yuting Tao, Shaohua Jin, Tongbin Wang, Chongchong She, Kun Chen, Junfeng Wang, Lijie Li","doi":"10.3390/cryst14080711","DOIUrl":"https://doi.org/10.3390/cryst14080711","url":null,"abstract":"The cocrystallization of 1,3,5,7-tetranitro-1,3,5,7-tetrazolidine (HMX) with cyclopentanone was achieved via a controlled cooling method, followed by comprehensive characterization that confirmed the α-configuration of HMX within the cocrystal. The enthalpy of dissolution of HMX in cyclopentanone was assessed across a range of temperatures using a C-80 Calvert microcalorimeter, revealing an endothermic dissolution process. Subsequently, the molar enthalpy of dissolution was determined, and kinetic equations describing the dissolution rate were derived for temperatures of 303.15, 308.15, 313.15, 318.15, and 323.15 K as follows: dα⁄dt = 10−2.46(1 − α)0.35, dα⁄dt = 10−2.19(1 − α)0.79, dα⁄dt = 10−1.76(1 − α)1.32, dα⁄dt = 10−1.86(1 − α)0.46, and dα⁄dt = 10−2.02(1 − α)0.70, respectively. Additionally, molecular dynamics (MD) simulations investigated the intermolecular interactions of the HMX/cyclopentanone cocrystallization process, demonstrating a transformation of HMX from β- to α-conformation within the cyclopentanone environment. Theoretical calculations performed at the ωB97XD/6-311G(d,p) level affirmed that α-HMX exhibited stronger binding affinity toward cyclopentanone compared to β-HMX, corroborating experimental findings. A comprehensive understanding of the dissolution behavior of HMX in cyclopentanone holds significant implications for crystal growth methodologies and cocrystallization processes. Such insights are pivotal for optimizing HMX dissolution processes and offer valuable perspectives for developing and designing advanced energetic materials.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"9 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926317","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}
Steven Knerr, Erica Brendler, R. Gericke, Edwin Kroke, J. Wagler
Nitrilotris(methylenephenylphosphinic) acid (NTPAH3) was silylated using hexamethyldisilazane to produce the tris(trimethylsilyl) derivative NTPA(SiMe3)3. From the latter, upon alcoholysis in chloroform, NTPAH3 could be recovered. Thus, a new modification of that phosphinic acid formed. Meanwhile, NTPAH3 synthesized in aqueous hydrochloric acid crystallized in the space group P3c1 with the formation of O-H⋅⋅⋅O H-bonded networks (NTPAH3P), in chloroform crystals in the space group R3c formed (NTPAH3M), the constituents of which are individual molecules with exclusively intramolecular O-H⋅⋅⋅O hydrogen bonds. Both solids, NTPAH3P and NTPAH3M, were characterized by single-crystal X-ray diffraction, multi-nuclear (1H, 13C, 31P) solid-state NMR spectroscopy, and IR spectroscopy as well as quantum chemical calculations (both of their individual constituents as isolated molecules as well as in the periodic crystal environment). In spite of the different stabilities of their constituting molecular conformers, the different crystal packing interactions rendered the modifications of NTPAH3P and NTPAH3M similarly stable. In both solids, the protons of the acid are engaged in cyclic (O=P–O–H)3 H-bond trimers. Thus, the trialkylamine N atom of this compound is not protonated. IR and 1H NMR spectroscopy of these solids indicated stronger H-bonds in the (O=P–O–H)3 H-bond trimers of NTPAH3M over those in NTPAH3P.
使用六甲基二硅氮烷对三(亚甲基苯基)膦酸(NTPAH3)进行硅烷化处理，生成三(三甲基硅基)衍生物 NTPA(SiMe3)3。后者在氯仿中醇解后，可以回收 NTPAH3。因此，该膦酸形成了一种新的修饰。同时，在盐酸水溶液中合成的 NTPAH3 在空间群 P3c1 中结晶，形成 O-H⋅⋅O 氢键网络（NTPAH3P），在氯仿中形成空间群 R3c 的晶体（NTPAH3M），其成分是单个分子，只有分子内的 O-H⋅⋅O 氢键。我们通过单晶 X 射线衍射、多核（1H、13C、31P）固态核磁共振光谱、红外光谱以及量子化学计算（包括其单个成分作为孤立分子以及在周期晶体环境中的量子化学计算）对 NTPAH3P 和 NTPAH3M 这两种固体进行了表征。尽管它们构成的分子构象具有不同的稳定性，但不同的晶体堆积相互作用使得 NTPAH3P 和 NTPAH3M 的修饰具有相似的稳定性。在这两种固体中，酸的质子都参与了环状（O=P-O-H）3 H 键三聚体。因此，这种化合物的三烷基胺 N 原子没有质子化。这些固体的红外光谱和 1H NMR 光谱显示，NTPAH3M 的 (O=P-O-H)3 H 键三聚体中的 H 键比 NTPAH3P 中的更强。
{"title":"Two Modifications of Nitrilotris(methylenephenylphosphinic) Acid: A Polymeric Network with Intermolecular (O=P–O–H)3 vs. Monomeric Molecules with Intramolecular (O=P–O–H)3 Hydrogen Bond Cyclotrimers","authors":"Steven Knerr, Erica Brendler, R. Gericke, Edwin Kroke, J. Wagler","doi":"10.3390/cryst14070662","DOIUrl":"https://doi.org/10.3390/cryst14070662","url":null,"abstract":"Nitrilotris(methylenephenylphosphinic) acid (NTPAH3) was silylated using hexamethyldisilazane to produce the tris(trimethylsilyl) derivative NTPA(SiMe3)3. From the latter, upon alcoholysis in chloroform, NTPAH3 could be recovered. Thus, a new modification of that phosphinic acid formed. Meanwhile, NTPAH3 synthesized in aqueous hydrochloric acid crystallized in the space group P3c1 with the formation of O-H⋅⋅⋅O H-bonded networks (NTPAH3P), in chloroform crystals in the space group R3c formed (NTPAH3M), the constituents of which are individual molecules with exclusively intramolecular O-H⋅⋅⋅O hydrogen bonds. Both solids, NTPAH3P and NTPAH3M, were characterized by single-crystal X-ray diffraction, multi-nuclear (1H, 13C, 31P) solid-state NMR spectroscopy, and IR spectroscopy as well as quantum chemical calculations (both of their individual constituents as isolated molecules as well as in the periodic crystal environment). In spite of the different stabilities of their constituting molecular conformers, the different crystal packing interactions rendered the modifications of NTPAH3P and NTPAH3M similarly stable. In both solids, the protons of the acid are engaged in cyclic (O=P–O–H)3 H-bond trimers. Thus, the trialkylamine N atom of this compound is not protonated. IR and 1H NMR spectroscopy of these solids indicated stronger H-bonds in the (O=P–O–H)3 H-bond trimers of NTPAH3M over those in NTPAH3P.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":" 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823096","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}
Olga Goral, G. Żukowska, E. Żero, Maciej Siekierski, Anna Krzton-Maziopa
The crystallization behavior of avobenzone in cosmetic formulations has been investigated with a focus on its interaction with titanium dioxide and zinc oxide particles. Characterization studies using SEM, powder X-ray diffraction (PXRD), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDS) reveal that avobenzone undergoes crystallization facilitated by nucleation on the surfaces of these metal oxide grains. The presence of wax and titanium oxide within the crystalline structures further suggests a complex formation, potentially involving catalytic effects on avobenzone nucleation and isomerization. Notably, the addition of ascorbyl palmitate inhibits unwanted crystallization, possibly through competitive complexation with exposed metal ions. These findings underscore the significance of formulation modifications in stabilizing avobenzone against crystallization, ensuring enhanced product stability in cosmetic applications. Future structural studies are anticipated to elucidate the precise nature of these co-crystalline phases, offering insights into optimizing sunscreen formulations for improved performance and longevity.
我们研究了阿伏苯宗在化妆品配方中的结晶行为，重点是它与二氧化钛和氧化锌颗粒的相互作用。利用扫描电子显微镜、粉末 X 射线衍射 (PXRD)、拉曼光谱和能量色散 X 射线光谱 (EDS) 进行的表征研究表明，阿伏苯宗在这些金属氧化物颗粒表面的成核作用促进了其结晶。结晶结构中蜡和氧化钛的存在进一步表明，阿伏苯宗的成核和异构化可能涉及催化作用，从而形成了一种复合体。值得注意的是，添加抗坏血酸棕榈酸酯可抑制不必要的结晶，这可能是通过与暴露的金属离子竞争性络合实现的。这些发现强调了配方调整在稳定阿伏苯宗防止结晶方面的重要性，从而确保提高产品在化妆品应用中的稳定性。预计未来的结构研究将阐明这些共结晶相的确切性质，为优化防晒配方以提高性能和寿命提供启示。
{"title":"Understanding Avobenzone Crystallization in Sunscreen Formulations: Role of Metal Oxide-Driven Nucleation and Stabilization Strategies","authors":"Olga Goral, G. Żukowska, E. Żero, Maciej Siekierski, Anna Krzton-Maziopa","doi":"10.3390/cryst14070663","DOIUrl":"https://doi.org/10.3390/cryst14070663","url":null,"abstract":"The crystallization behavior of avobenzone in cosmetic formulations has been investigated with a focus on its interaction with titanium dioxide and zinc oxide particles. Characterization studies using SEM, powder X-ray diffraction (PXRD), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDS) reveal that avobenzone undergoes crystallization facilitated by nucleation on the surfaces of these metal oxide grains. The presence of wax and titanium oxide within the crystalline structures further suggests a complex formation, potentially involving catalytic effects on avobenzone nucleation and isomerization. Notably, the addition of ascorbyl palmitate inhibits unwanted crystallization, possibly through competitive complexation with exposed metal ions. These findings underscore the significance of formulation modifications in stabilizing avobenzone against crystallization, ensuring enhanced product stability in cosmetic applications. Future structural studies are anticipated to elucidate the precise nature of these co-crystalline phases, offering insights into optimizing sunscreen formulations for improved performance and longevity.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":" 1069","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823173","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}
Ying Chieh Hu, Hyun Soo Ahn, Joo Hyeong Lee, Kyung Hoon Kim, Jong Hun Kim, Jong Hoon Jung
The poly (vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) P(VDF-TrFE-CFE) terpolymer has been identified as a promising candidate for the effective conversion of low-frequency mechanical vibrations into electricity. In this study, we provide a comprehensive and systematic investigation of the solvent-dependent mechanical, microstructural, electrical, frictional properties and triboelectric output performance of a relaxor ferroelectric P(VDF-TrFE-CFE) terpolymer. The P(VDF-TrFE-CFE) terpolymer films obtained from high dipole moment solvents have a longer rod-shaped grain than those from low dipole moment solvents. The crystallinity, Young’s modulus and dielectric constant of P(VDF-TrFE-CFE) terpolymer become larger as the dipole moment of solvents increases, while the remnant polarization remains almost the same. The P(VDF-TrFE-CFE) terpolymer film obtained from the highest dipole moment solvent generates almost 1.55 times larger triboelectric charge than that obtained from the lowest moment. We attributed this large difference to the greatly enhanced lateral friction of terpolymer film obtained from high dipole moment solvents.
{"title":"Solvent-Dependent Triboelectric Output Performance of Poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) Terpolymer","authors":"Ying Chieh Hu, Hyun Soo Ahn, Joo Hyeong Lee, Kyung Hoon Kim, Jong Hun Kim, Jong Hoon Jung","doi":"10.3390/cryst14070664","DOIUrl":"https://doi.org/10.3390/cryst14070664","url":null,"abstract":"The poly (vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) P(VDF-TrFE-CFE) terpolymer has been identified as a promising candidate for the effective conversion of low-frequency mechanical vibrations into electricity. In this study, we provide a comprehensive and systematic investigation of the solvent-dependent mechanical, microstructural, electrical, frictional properties and triboelectric output performance of a relaxor ferroelectric P(VDF-TrFE-CFE) terpolymer. The P(VDF-TrFE-CFE) terpolymer films obtained from high dipole moment solvents have a longer rod-shaped grain than those from low dipole moment solvents. The crystallinity, Young’s modulus and dielectric constant of P(VDF-TrFE-CFE) terpolymer become larger as the dipole moment of solvents increases, while the remnant polarization remains almost the same. The P(VDF-TrFE-CFE) terpolymer film obtained from the highest dipole moment solvent generates almost 1.55 times larger triboelectric charge than that obtained from the lowest moment. We attributed this large difference to the greatly enhanced lateral friction of terpolymer film obtained from high dipole moment solvents.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":" 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822908","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}
K. Kamburova, N. Boshkova, T. Radeva, M. Shipochka, N. Boshkov
The introduction of new regulations needs to develop eco-friendly systems to prevent corrosion. In this work, a natural corrosion inhibitor caffeine (CAF) was encapsulated in polysaccharide-based nanoparticles, capable of the responsive release of CAF during corrosion. The nanoparticles were prepared using electrostatic complexation between two natural polysaccharides which are oppositely charged—chitosan (CHI) and sodium alginate (ALG), crosslinked by tripolyphosphate (TPP). The particle size distribution and zeta potential were evaluated using dynamic light scattering and laser Doppler velocimetry. The encapsulation efficiency and release of CAF from nanocontainers was evaluated with UV-spectroscopy. The nanoparticles were incorporated via electrodeposition into the zinc coating on low-carbon steel to ensure self-healing. Cyclic voltammetry demonstrated the cathodic and anodic processes in the starting electrolytes. Surface hydrophobicity was investigated by water contact angle (WCA). The corrosion resistance of the coatings was estimated with polarization resistance (Rp) measurements and potentiodynamic polarization (PDP) curves. The study of the chemical composition of the coatings was carried out with X-ray photoelectron spectroscopy. The data obtained confirm the indisputable influence of the nanoparticles/nanocontainers on the protective feature of the hybrids—the latter have about twice-higher Rp values compared to the ordinary zinc.
新法规的出台需要开发生态友好型系统来防止腐蚀。在这项工作中，一种天然缓蚀剂咖啡因（CAF）被封装在多糖基纳米粒子中，能够在腐蚀过程中响应性地释放 CAF。该纳米粒子是利用两种带相反电荷的天然多糖-壳聚糖（CHI）和海藻酸钠（ALG）-之间的静电络合制备的，并通过三聚磷酸钠（TPP）交联。使用动态光散射和激光多普勒测速仪对粒度分布和 zeta 电位进行了评估。用紫外光谱法评估了纳米容器的封装效率和 CAF 的释放。纳米粒子通过电沉积的方式加入到低碳钢的锌涂层中，以确保自愈合。循环伏安法显示了起始电解质中的阴极和阳极过程。通过水接触角（WCA）研究了表面疏水性。通过极化电阻（Rp）测量和电位极化（PDP）曲线估算了涂层的耐腐蚀性。利用 X 射线光电子能谱对涂层的化学成分进行了研究。所获得的数据证实了纳米颗粒/纳米容器对混合涂层保护特性的无可争议的影响--后者的 Rp 值是普通锌的两倍。
{"title":"Chitosan–Alginate Nanocontainers with Caffeine as Green Corrosion Inhibitors for Protection of Galvanized Steel","authors":"K. Kamburova, N. Boshkova, T. Radeva, M. Shipochka, N. Boshkov","doi":"10.3390/cryst14070660","DOIUrl":"https://doi.org/10.3390/cryst14070660","url":null,"abstract":"The introduction of new regulations needs to develop eco-friendly systems to prevent corrosion. In this work, a natural corrosion inhibitor caffeine (CAF) was encapsulated in polysaccharide-based nanoparticles, capable of the responsive release of CAF during corrosion. The nanoparticles were prepared using electrostatic complexation between two natural polysaccharides which are oppositely charged—chitosan (CHI) and sodium alginate (ALG), crosslinked by tripolyphosphate (TPP). The particle size distribution and zeta potential were evaluated using dynamic light scattering and laser Doppler velocimetry. The encapsulation efficiency and release of CAF from nanocontainers was evaluated with UV-spectroscopy. The nanoparticles were incorporated via electrodeposition into the zinc coating on low-carbon steel to ensure self-healing. Cyclic voltammetry demonstrated the cathodic and anodic processes in the starting electrolytes. Surface hydrophobicity was investigated by water contact angle (WCA). The corrosion resistance of the coatings was estimated with polarization resistance (Rp) measurements and potentiodynamic polarization (PDP) curves. The study of the chemical composition of the coatings was carried out with X-ray photoelectron spectroscopy. The data obtained confirm the indisputable influence of the nanoparticles/nanocontainers on the protective feature of the hybrids—the latter have about twice-higher Rp values compared to the ordinary zinc.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":"103 50","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141820741","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}
In our research, we apply electrophoretic deposition (EPD) using AC voltage to investigate how high-C-rate electrochemical reactions affect pseudocapacitive charge storage in lithium iron phosphate (LFP) Li-ion batteries. This method significantly raises the battery’s specific capacity, achieving ~90 mAh/g at a 1 C-rate, along with outstanding cycle stability. Although we observe some capacity reduction over numerous cycles, there is a notable increase in the pseudocapacitive contribution to the battery’s charge storage. This is demonstrated by the consistent peak positions and currents during CV and a stable diffusion constant maintained at 9.6 × 10−9 cm2∙s−1. These findings highlight the battery’s durability, especially in high-demand scenarios. After an extended cycling period of ~500 cycles, the redox peaks related to the Fe2+/Fe3+ redox processes remain unchanged in terms of magnitude and position, indicating the battery’s excellent reversibility.
在我们的研究中，我们利用交流电压进行电泳沉积（EPD），研究高 C 速率电化学反应如何影响磷酸铁锂（LFP）锂离子电池中的伪电容电荷存储。这种方法大大提高了电池的比容量，在 1 C 速率下可达到约 90 mAh/g，同时具有出色的循环稳定性。虽然我们观察到电池容量在多次循环后有所下降，但电池的电荷存储的伪电容贡献却明显增加。这表现在：CV 期间的峰值位置和电流保持一致，扩散常数稳定在 9.6 × 10-9 cm2∙s-1 的水平。这些发现凸显了电池的耐用性，尤其是在高需求情况下。在经过约 500 次的循环后，与 Fe2+/Fe3+ 氧化还原过程相关的氧化还原峰值在大小和位置上保持不变，这表明电池具有出色的可逆性。
{"title":"An Electrochemical-Cycling-Induced Capacitive Component on the Surface of an Electrophoretic-Deposited Lithium Iron Phosphate Cathode","authors":"Byoung-Nam Park","doi":"10.3390/cryst14070658","DOIUrl":"https://doi.org/10.3390/cryst14070658","url":null,"abstract":"In our research, we apply electrophoretic deposition (EPD) using AC voltage to investigate how high-C-rate electrochemical reactions affect pseudocapacitive charge storage in lithium iron phosphate (LFP) Li-ion batteries. This method significantly raises the battery’s specific capacity, achieving ~90 mAh/g at a 1 C-rate, along with outstanding cycle stability. Although we observe some capacity reduction over numerous cycles, there is a notable increase in the pseudocapacitive contribution to the battery’s charge storage. This is demonstrated by the consistent peak positions and currents during CV and a stable diffusion constant maintained at 9.6 × 10−9 cm2∙s−1. These findings highlight the battery’s durability, especially in high-demand scenarios. After an extended cycling period of ~500 cycles, the redox peaks related to the Fe2+/Fe3+ redox processes remain unchanged in terms of magnitude and position, indicating the battery’s excellent reversibility.","PeriodicalId":505131,"journal":{"name":"Crystals","volume":" 39","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141827110","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}
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