Pub Date : 2024-08-06DOI: 10.1088/1361-6463/ad6882
Florin Bilea, Corina Bradu, Andrei V Medvedovici, Dunpin Hong and Monica Magureanu
Water pollution is one of the most significant problems of the current century. With the increase in medicine availability and use, pharmaceutical pollutants such as antibiotics become more prevalent in natural environments with potentially negative impact. In this study, a pulsed corona discharge was investigated as a possible treatment method of water contaminated with amoxicillin (AMX). Two system configurations were used: plasma and plasma-ozonation. In order to better grasp the effect of system and water matrix on degradation, different pulse widths, solutions pH and conductivity values, as well as the nature of the dissolved salts were investigated. Decreasing the pulse width from 300 ns to 106 ns (full width at half maximum) led to almost a two-fold increase in energy yield at 50% pollutant removal, and the addition of the ozonation reactor resulted six times enhancement in efficiency. While the water matrix had little impact on AMX degradation, the buffering capacity of carbonates has proven beneficial by preventing pH decrease during treatment. Under optimum conditions, the energy yield was 57 g kWh−1 at 93% removal of AMX in tap water. A number of 26 potential degradation products have been identified, resulting from hydroxylation of the benzene ring, oxidation of the thioester and amine groups, hydrolysis, and cleavage of the benzene, β-lactam and thiazole rings, along with fragmentation of the resulting compounds. All but seven degradation intermediates are completely removed by extending treatment duration to 60 min and the persistent ones are less toxic than the parent compound.
{"title":"Pulsed corona discharge: an advanced treatment method for antibiotic-contaminated water","authors":"Florin Bilea, Corina Bradu, Andrei V Medvedovici, Dunpin Hong and Monica Magureanu","doi":"10.1088/1361-6463/ad6882","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6882","url":null,"abstract":"Water pollution is one of the most significant problems of the current century. With the increase in medicine availability and use, pharmaceutical pollutants such as antibiotics become more prevalent in natural environments with potentially negative impact. In this study, a pulsed corona discharge was investigated as a possible treatment method of water contaminated with amoxicillin (AMX). Two system configurations were used: plasma and plasma-ozonation. In order to better grasp the effect of system and water matrix on degradation, different pulse widths, solutions pH and conductivity values, as well as the nature of the dissolved salts were investigated. Decreasing the pulse width from 300 ns to 106 ns (full width at half maximum) led to almost a two-fold increase in energy yield at 50% pollutant removal, and the addition of the ozonation reactor resulted six times enhancement in efficiency. While the water matrix had little impact on AMX degradation, the buffering capacity of carbonates has proven beneficial by preventing pH decrease during treatment. Under optimum conditions, the energy yield was 57 g kWh−1 at 93% removal of AMX in tap water. A number of 26 potential degradation products have been identified, resulting from hydroxylation of the benzene ring, oxidation of the thioester and amine groups, hydrolysis, and cleavage of the benzene, β-lactam and thiazole rings, along with fragmentation of the resulting compounds. All but seven degradation intermediates are completely removed by extending treatment duration to 60 min and the persistent ones are less toxic than the parent compound.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"72 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1088/1361-6463/ad687c
Der-Yuh Lin, Yu-Tai Shih, De-Jin Qiu, Yee-Mou Kao, Sheng-Beng Hwang, Ming-Cheng Kao and Chia-Feng Lin
A facile, cost-effective, and scalable chemical vapor deposition technique was used to synthesize p-type Cu2Se thin films on glass and n-type Si substrates. Thorough characterization confirmed the films’ β-phase structure with the correct stoichiometric ratio and exceptional crystalline quality, exhibiting behavior akin to a degenerate semiconductor. Measurements unveiled a work function of 4.83 eV and a bandgap of 2.13 eV for Cu2Se. The fabrication of a p-Cu2Se/n-Si heterojunction was achieved by depositing the p-type Cu2Se thin film onto the n-type Si substrate. The resulting heterostructure displayed rectification behavior, and its energy band diagram resembled a Schottky diode. Further exploration into its photoelectric properties showcased the p-Cu2Se/n-Si heterostructure’s favorable self-powered attribute, characterized by fast, steady, reproducible, sensitive, and robust photoresponsive performance. Consequently, it proves highly suitable for applications in high-frequency photodetectors. Additionally, the p-Cu2Se/n-Si heterojunction’s photovoltaic power conversion efficiency exceeded the reported values of the CuO/Si and Cu2O/Si systems. Here, this study contributes significantly to the pivotal evaluation of p-Cu2Se/n-Si heterostructures for promising optoelectronic applications.
该研究采用了一种简便、经济、可扩展的化学气相沉积技术，在玻璃和 n 型硅基底上合成了 p 型 Cu2Se 薄膜。彻底的表征证实了薄膜的 β 相结构具有正确的化学计量比和优异的结晶质量，表现出类似于退变型半导体的行为。测量结果显示，Cu2Se 的功函数为 4.83 eV，带隙为 2.13 eV。通过在 n 型硅衬底上沉积 p 型 Cu2Se 薄膜，实现了 p-Cu2Se/n-Si 异质结的制造。由此产生的异质结显示出整流行为，其能带图类似于肖特基二极管。对其光电特性的进一步研究表明，p-Cu2Se/n-Si 异质结构具有良好的自供电特性，其特点是快速、稳定、可重现、灵敏和稳健的光致发光性能。因此，它非常适合应用于高频光电探测器。此外，p-Cu2Se/n-Si 异质结的光电转换效率超过了 CuO/Si 和 Cu2O/Si 系统的报告值。这项研究为评估对铜2硅/非晶硅异质结构的光电应用前景做出了重要贡献。
{"title":"Facile synthesis and characterization of Cu2Se thin films and self-powered p-Cu2Se/n-Si heterojunction with high-performance photoresponse","authors":"Der-Yuh Lin, Yu-Tai Shih, De-Jin Qiu, Yee-Mou Kao, Sheng-Beng Hwang, Ming-Cheng Kao and Chia-Feng Lin","doi":"10.1088/1361-6463/ad687c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad687c","url":null,"abstract":"A facile, cost-effective, and scalable chemical vapor deposition technique was used to synthesize p-type Cu2Se thin films on glass and n-type Si substrates. Thorough characterization confirmed the films’ β-phase structure with the correct stoichiometric ratio and exceptional crystalline quality, exhibiting behavior akin to a degenerate semiconductor. Measurements unveiled a work function of 4.83 eV and a bandgap of 2.13 eV for Cu2Se. The fabrication of a p-Cu2Se/n-Si heterojunction was achieved by depositing the p-type Cu2Se thin film onto the n-type Si substrate. The resulting heterostructure displayed rectification behavior, and its energy band diagram resembled a Schottky diode. Further exploration into its photoelectric properties showcased the p-Cu2Se/n-Si heterostructure’s favorable self-powered attribute, characterized by fast, steady, reproducible, sensitive, and robust photoresponsive performance. Consequently, it proves highly suitable for applications in high-frequency photodetectors. Additionally, the p-Cu2Se/n-Si heterojunction’s photovoltaic power conversion efficiency exceeded the reported values of the CuO/Si and Cu2O/Si systems. Here, this study contributes significantly to the pivotal evaluation of p-Cu2Se/n-Si heterostructures for promising optoelectronic applications.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"43 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-05DOI: 10.1088/1361-6463/ad6876
Chunqi Jiang, Akash C Dhotre, Meimei Lai, Sayan Biswas, James R MacDonald and Isaac W Ekoto
The effect of transient plasma modes on ignition kernel development are discussed here for a quiescent CH4-air combustion model system. A 10 ns high-voltage pulse was applied to a pin-to-pin electrode in lean fuel-air mixtures at room temperature and atmospheric pressure. High-impedance streamer, transient spark and low-impedance spark discharges were identified based on pulse waveforms of voltage and current. A sustained ignition kernel expansion was observed when the plasma discharge transitioned into a transient spark or spark discharge. The minimum ignition energy was obtained at the transient spark mode, which has less than a third of the energy or Coulomb transfer compared to the low-impedance spark. Employing repetitive 10-pulse sequence at 10 kHz, the lean-fuel limit was extended from an equivalence ratio of 0.6 for the single pulse ignition to 0.5. The use of repetitive pulses also allowed streamer breakdown or spark initiation to occur at a lower voltage.
{"title":"On the modes of nanosecond pulsed plasmas for combustion ignition of quiescent CH4-air mixtures","authors":"Chunqi Jiang, Akash C Dhotre, Meimei Lai, Sayan Biswas, James R MacDonald and Isaac W Ekoto","doi":"10.1088/1361-6463/ad6876","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6876","url":null,"abstract":"The effect of transient plasma modes on ignition kernel development are discussed here for a quiescent CH4-air combustion model system. A 10 ns high-voltage pulse was applied to a pin-to-pin electrode in lean fuel-air mixtures at room temperature and atmospheric pressure. High-impedance streamer, transient spark and low-impedance spark discharges were identified based on pulse waveforms of voltage and current. A sustained ignition kernel expansion was observed when the plasma discharge transitioned into a transient spark or spark discharge. The minimum ignition energy was obtained at the transient spark mode, which has less than a third of the energy or Coulomb transfer compared to the low-impedance spark. Employing repetitive 10-pulse sequence at 10 kHz, the lean-fuel limit was extended from an equivalence ratio of 0.6 for the single pulse ignition to 0.5. The use of repetitive pulses also allowed streamer breakdown or spark initiation to occur at a lower voltage.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"25 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1088/1361-6463/ad5e90
Sushmita Saha, Alestin Mawrie
The exquisite distortion in a Kekulé -Y (Kek-Y) superlattice merges the two inequivalent Dirac cones (from the K- and the K′- points) into the highest symmetric Γ-point in the hexagonal Brillouin zone. Here, we report that UV circularly polarized light not only opens up a topological gap at the Γ-point, but also lifts the valley degeneracy at that point. Endowed with Floquet dynamics and by devising a scheme of high-frequency approximation, we propose that the left/right-handedness in polarized light offers the possibility to realize valley-selective circular dichroism in a Kek-Y-shaped graphene superlattice. In addition, the non-vanishing Berry curvature and enumeration of the valley-resolved Chern number CK/CK′=+1/−1 enable us to assign two pseudospin flavors (up/down) with the two valleys. Thereby, the above observations confirm the topological transition, suggesting the ease of realizing the valley quantum anomalous Hall state within the photon-dressed Kek-Y. These findings further manifest a non-zero optical valley polarization that is maximal at the Γ-point. Our paper thus proposes an optically switchable topological valley filter, which is desired in the evolving landscape of valleytronics.
{"title":"Floquet-engineered valley topotronics in Kekulé-Y bond textured graphene superlattice","authors":"Sushmita Saha, Alestin Mawrie","doi":"10.1088/1361-6463/ad5e90","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5e90","url":null,"abstract":"The exquisite distortion in a Kekulé -Y (Kek-Y) superlattice merges the two inequivalent Dirac cones (from the <italic toggle=\"yes\">K</italic>- and the <italic toggle=\"yes\">K</italic>′- points) into the highest symmetric Γ-point in the hexagonal Brillouin zone. Here, we report that UV circularly polarized light not only opens up a topological gap at the Γ-point, but also lifts the valley degeneracy at that point. Endowed with Floquet dynamics and by devising a scheme of high-frequency approximation, we propose that the left/right-handedness in polarized light offers the possibility to realize valley-selective circular dichroism in a Kek-Y-shaped graphene superlattice. In addition, the non-vanishing Berry curvature and enumeration of the valley-resolved Chern number <inline-formula>\u0000<tex-math><?CDATA $mathcal{C}_{K}/mathcal{C}_{K^{prime}} = +1/-1$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:mi>K</mml:mi></mml:mrow></mml:msub><mml:mrow><mml:mo>/</mml:mo></mml:mrow><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:msup><mml:mi>K</mml:mi><mml:mi>′</mml:mi></mml:msup></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mo>+</mml:mo><mml:mn>1</mml:mn><mml:mrow><mml:mo>/</mml:mo></mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"dad5e90ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> enable us to assign two pseudospin flavors (up/down) with the two valleys. Thereby, the above observations confirm the topological transition, suggesting the ease of realizing the valley quantum anomalous Hall state within the photon-dressed Kek-Y. These findings further manifest a non-zero optical valley polarization that is maximal at the Γ-point. Our paper thus proposes an optically switchable topological valley filter, which is desired in the evolving landscape of valleytronics.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"26 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141872973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.1088/1361-6463/ad6455
Zhuoao Du, Bin Luo, Zhigang Chen, Meiyu Zhu, Kejun Zhu, Yanjie Wang
Polyvinyl chloride (PVC) gel generates complex nonlinear vibration behavior under an alternating current voltage excitation, which has potential application as a dynamic electromechanical actuator. However, there are few studies on the deformation theory of PVC gel actuators, especially the dynamic nonlinear response theory. In this paper, a complex dynamic model is established according to the electrodeformation mechanism of PVC film, and the nonlinear dynamic behavior of the actuator is numerically studied by a differential equation. The effects of applied voltage amplitude, voltage frequency, dibutyl adipate content, mechanical tension, and bias voltage on the dynamic properties of PVC film were analyzed under the condition of equal biaxial tension. The variation of amplitude and the generation and disappearance of the beat frequency during vibration are analyzed by using time-domain characteristics. The degree of PVC actuator nonlinearity as well as vibration stability and periodicity is also reflected based on the phase path and Poincare map. Finally, the law of influence of external condition parameters on the dynamic response of the PVC actuator is obtained.
{"title":"Deformation theory and nonlinear dynamic behavior of PVC gel actuators","authors":"Zhuoao Du, Bin Luo, Zhigang Chen, Meiyu Zhu, Kejun Zhu, Yanjie Wang","doi":"10.1088/1361-6463/ad6455","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6455","url":null,"abstract":"Polyvinyl chloride (PVC) gel generates complex nonlinear vibration behavior under an alternating current voltage excitation, which has potential application as a dynamic electromechanical actuator. However, there are few studies on the deformation theory of PVC gel actuators, especially the dynamic nonlinear response theory. In this paper, a complex dynamic model is established according to the electrodeformation mechanism of PVC film, and the nonlinear dynamic behavior of the actuator is numerically studied by a differential equation. The effects of applied voltage amplitude, voltage frequency, dibutyl adipate content, mechanical tension, and bias voltage on the dynamic properties of PVC film were analyzed under the condition of equal biaxial tension. The variation of amplitude and the generation and disappearance of the beat frequency during vibration are analyzed by using time-domain characteristics. The degree of PVC actuator nonlinearity as well as vibration stability and periodicity is also reflected based on the phase path and Poincare map. Finally, the law of influence of external condition parameters on the dynamic response of the PVC actuator is obtained.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"17 3 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.1088/1361-6463/ad6456
Li Xie, Yongjin Han and Yang Huang
In this paper, the heat treatment of alumina fiber was studied. The infiltration agent on the fiber surface was removed after heat treatment at 450 °C for 6 h. TG-DSC, scanning electron microscope, x-ray diffraction, Fourier infrared spectrometer, energy dispersive spectrometer, and patterning were used to analyze the thermal weight loss, fiber surface morphology, crystal structure, and composition of alumina fibers. The results show that the aluminum oxide fiber has excellent temperature resistance and does not undergo crystal phase transformation during thermal weight loss. After heat treatment, the fiber surface infiltration agent ablates and dissolves from the fiber surface, and the internal crystal structure of the fiber remains stable. The tensile testing machine was utilized to test the breaking strength of alumina fiber. The fiber still maintained high strength after heat treatment, and the retention rate of breaking strength was greater than 74%. ZC-90G high insulation resistance measuring instrument and WDY-Ⅱ automatic voltage tester were utilized to analyze the insulation resistivity and breakdown strength of alumina fiber before and after heat treatment. The results show that heat treatment can effectively improve the insulation performance and breakdown strength of alumina fiber.
{"title":"Study on the effect of heat treatment on the structure, mechanical and electrical properties of alumina fiber insulation","authors":"Li Xie, Yongjin Han and Yang Huang","doi":"10.1088/1361-6463/ad6456","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6456","url":null,"abstract":"In this paper, the heat treatment of alumina fiber was studied. The infiltration agent on the fiber surface was removed after heat treatment at 450 °C for 6 h. TG-DSC, scanning electron microscope, x-ray diffraction, Fourier infrared spectrometer, energy dispersive spectrometer, and patterning were used to analyze the thermal weight loss, fiber surface morphology, crystal structure, and composition of alumina fibers. The results show that the aluminum oxide fiber has excellent temperature resistance and does not undergo crystal phase transformation during thermal weight loss. After heat treatment, the fiber surface infiltration agent ablates and dissolves from the fiber surface, and the internal crystal structure of the fiber remains stable. The tensile testing machine was utilized to test the breaking strength of alumina fiber. The fiber still maintained high strength after heat treatment, and the retention rate of breaking strength was greater than 74%. ZC-90G high insulation resistance measuring instrument and WDY-Ⅱ automatic voltage tester were utilized to analyze the insulation resistivity and breakdown strength of alumina fiber before and after heat treatment. The results show that heat treatment can effectively improve the insulation performance and breakdown strength of alumina fiber.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"57 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.1088/1361-6463/ad5b70
Vitaly Yu Topolov
The results of a comparative study on piezo-active 2–1–2 composites with two ferroelectric components are discussed. The composite structure combines elements of 2–2 (laminar) and 1–3 (fibrous) connectivity patterns. The first component in each composite is domain-engineered [0 1 1]-poled single crystal with macroscopic mm2 symmetry and high piezoelectric activity. The second component is a poled ferroelectric ceramic that is represented by parallel rods in the shape of an elliptic cylinder with a large ratio of semi-axes at its base. The first orientation effect is appreciable due to rotations of the main crystallographic axes X and Y around Z || OX3 by an angle α in each crystal layer. Rotation of the ceramic rod bases by an angle γ in a polymer medium leads to the second orientation effect in the 2–1–2 composite. The two orientation effects contribute to a large anisotropy of electromechanical coupling factors , energy-harvesting figures of merit (FOM) and modified FOM for a stress-driven harvester. The large level of , , and (these parameters are of the order of 10−11–10−10 Pa−1) indicates that the studied composites are suitable for piezoelectric sensors, transducers and energy-harvesting systems. New m—α diagrams put forward in the present study show regions wherein the large anisotropy of the effective parameters ( / , )2 and , f = 1 and 2) is achieved when changing the volume fraction m of the single crystal and the rotation angle α. As a result, the leading role of the first orientation effect is emphasised.
本文讨论了对含有两种铁电成分的压电活性 2-1-2 复合材料进行比较研究的结果。复合材料结构结合了 2-2（层状）和 1-3（纤维状）连接模式的元素。每种复合材料的第一种成分是畴工程[0 1 1]极化单晶，具有宏观 mm2 对称性和高压电活性。第二种成分是极化铁电陶瓷，它由平行棒组成，呈椭圆柱状，底部的半轴比很大。由于每个晶体层中的主要晶体学轴 X 和 Y 围绕 Z || OX3 旋转了 α 角，因此第一种取向效应非常明显。陶瓷棒基在聚合物介质中旋转 γ 角导致了 2-1-2 复合材料中的第二种取向效应。这两种取向效应导致机电耦合系数、能量收集功勋值（FOM）和应力驱动收集器的修正 FOM 存在较大的各向异性。较大的、、和（这些参数的数量级为 10-11-10-10 Pa-1）表明，所研究的复合材料适用于压电传感器、换能器和能量收集系统。本研究提出的新 m-α 图显示，当改变单晶体的体积分数 m 和旋转角度 α 时，有效参数 ( / , )2 和 , f = 1 和 2) 的大各向异性区域。因此，第一取向效应的主导作用得到了强调。
{"title":"Two orientation effects and large anisotropy of parameters in piezo-active 2–1–2 composites based on [0 1 1]-poled crystals","authors":"Vitaly Yu Topolov","doi":"10.1088/1361-6463/ad5b70","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5b70","url":null,"abstract":"The results of a comparative study on piezo-active 2–1–2 composites with two ferroelectric components are discussed. The composite structure combines elements of 2–2 (laminar) and 1–3 (fibrous) connectivity patterns. The first component in each composite is domain-engineered [0 1 1]-poled single crystal with macroscopic mm2 symmetry and high piezoelectric activity. The second component is a poled ferroelectric ceramic that is represented by parallel rods in the shape of an elliptic cylinder with a large ratio of semi-axes at its base. The first orientation effect is appreciable due to rotations of the main crystallographic axes X and Y around Z || OX3 by an angle α in each crystal layer. Rotation of the ceramic rod bases by an angle γ in a polymer medium leads to the second orientation effect in the 2–1–2 composite. The two orientation effects contribute to a large anisotropy of electromechanical coupling factors , energy-harvesting figures of merit (FOM) and modified FOM for a stress-driven harvester. The large level of , , and (these parameters are of the order of 10−11–10−10 Pa−1) indicates that the studied composites are suitable for piezoelectric sensors, transducers and energy-harvesting systems. New m—α diagrams put forward in the present study show regions wherein the large anisotropy of the effective parameters ( / , )2 and , f = 1 and 2) is achieved when changing the volume fraction m of the single crystal and the rotation angle α. As a result, the leading role of the first orientation effect is emphasised.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"21 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1088/1361-6463/ad5b02
Roman B Morgunov, Sergey N Kashin, Ekaterina I Kunitsyna, Artem D Talantsev and Aleksander I Chernov
Multiple noncollinear spin structures and transitions between them initiated by field and temperature have attracted attention due to the extraordinary coexistence of complicated spin phases in Ho. We explore the magnetic relaxation dynamics within thin films undergoing transitions between ferromagnetic (FM) and helix states. When measuring susceptibility in a relatively high frequency range (∼100–1500 Hz) and magnetic viscosity at lower frequency (∼0.01 Hz), we focus on 400 nm thick Ho film. Notably, sharp variations in the real and imaginary components of magnetic susceptibility are discerned during the FM – Helix transition, occurring at temperatures between 15 and 30 K. Hysteresis effects in the magnetic susceptibility components are identified during cyclic variations in the external field, indicating a relatively rapid process with a timescale of approximately 10 ms accompanying the FM – Helix transition. The slow relaxation process is also found to exhibit sensitivity to this transition. Furthermore, the field dependence of magnetic viscosity displays a marked decline at the FM – Helix transition. The research methodologies proposed for the investigation of relaxation processes in materials with multiphase spin structures are deemed universally applicable and offer insights into transitions between spin states in materials manifesting non collinear spin structures.
多种非共轭自旋结构以及由磁场和温度引发的它们之间的转变引起了人们的关注，因为在 Ho 中复杂的自旋相非同寻常地共存。我们探索了在铁磁（FM）态和螺旋态之间发生转变的薄膜内部的磁弛豫动力学。在测量相对较高频率范围（∼100-1500 Hz）的磁感应强度和较低频率（∼0.01 Hz）的磁粘性时，我们以 400 nm 厚的 Ho 薄膜为研究对象。值得注意的是，在调频-螺旋转换期间，磁感应强度的实分量和虚分量发生了急剧变化，发生在 15 至 30 K 的温度范围内。在外部磁场周期性变化期间，磁感应强度分量的磁滞效应被识别出来，这表明调频-螺旋转换是一个相对快速的过程，时间尺度约为 10 ms。此外，还发现缓慢的弛豫过程对这一转变非常敏感。此外，磁性粘度的磁场依赖性在调频-螺旋转换时明显下降。为研究具有多相自旋结构的材料中的弛豫过程而提出的研究方法被认为是普遍适用的，并为研究具有非对偶自旋结构的材料中自旋态之间的转变提供了见解。
{"title":"Magnetic relaxation between ferromagnetic and helix spin configurations in holmium films","authors":"Roman B Morgunov, Sergey N Kashin, Ekaterina I Kunitsyna, Artem D Talantsev and Aleksander I Chernov","doi":"10.1088/1361-6463/ad5b02","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5b02","url":null,"abstract":"Multiple noncollinear spin structures and transitions between them initiated by field and temperature have attracted attention due to the extraordinary coexistence of complicated spin phases in Ho. We explore the magnetic relaxation dynamics within thin films undergoing transitions between ferromagnetic (FM) and helix states. When measuring susceptibility in a relatively high frequency range (∼100–1500 Hz) and magnetic viscosity at lower frequency (∼0.01 Hz), we focus on 400 nm thick Ho film. Notably, sharp variations in the real and imaginary components of magnetic susceptibility are discerned during the FM – Helix transition, occurring at temperatures between 15 and 30 K. Hysteresis effects in the magnetic susceptibility components are identified during cyclic variations in the external field, indicating a relatively rapid process with a timescale of approximately 10 ms accompanying the FM – Helix transition. The slow relaxation process is also found to exhibit sensitivity to this transition. Furthermore, the field dependence of magnetic viscosity displays a marked decline at the FM – Helix transition. The research methodologies proposed for the investigation of relaxation processes in materials with multiphase spin structures are deemed universally applicable and offer insights into transitions between spin states in materials manifesting non collinear spin structures.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"78 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141753989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1088/1361-6463/ad5f9b
Fen Zhao, Baoze Huang, Qingxiao Liu and Junbo Yang
A design method is proposed for a broadband super-resolution wavelength-controlled zoom metalens with simultaneous modulation of phase, dispersion, and amplitude, and on the basis of enhancing the axial zoom capability of the metalens, the point spread function of the metalens is continuously compressed using the hierarchical direct binary search algorithm, so that the full width at half maximum of the metalens is continuously close to or even less than the diffraction limit of 0.5λ/NA (NA is the numerical aperture). As a theoretical verification, a super-resolution wavelength-controlled zoom metalens was designed operating in the wavelength range of 68–80 μm. The simulation results show that its axial zoom capability is about 1.65 times that of the conventional diffractive metalens, and the lateral resolution in the wavelength range of 68–80 μm is less than the diffraction limit.
{"title":"Broadband super-resolution wavelength-controlled zoom metalens","authors":"Fen Zhao, Baoze Huang, Qingxiao Liu and Junbo Yang","doi":"10.1088/1361-6463/ad5f9b","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5f9b","url":null,"abstract":"A design method is proposed for a broadband super-resolution wavelength-controlled zoom metalens with simultaneous modulation of phase, dispersion, and amplitude, and on the basis of enhancing the axial zoom capability of the metalens, the point spread function of the metalens is continuously compressed using the hierarchical direct binary search algorithm, so that the full width at half maximum of the metalens is continuously close to or even less than the diffraction limit of 0.5λ/NA (NA is the numerical aperture). As a theoretical verification, a super-resolution wavelength-controlled zoom metalens was designed operating in the wavelength range of 68–80 μm. The simulation results show that its axial zoom capability is about 1.65 times that of the conventional diffractive metalens, and the lateral resolution in the wavelength range of 68–80 μm is less than the diffraction limit.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"49 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141753990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flexoelectricity, denoted as an electromechanical coupling effect from strain gradient introduced polarization, is prevalent in dielectric materials. However, its application in low-viscosity liquids has been limited by the scale of the flexoelectric coefficient. This study explores the flexoelectric coefficient of various hydrated ion solutions through a series of experiments. Additionally, the interplay between ion adsorption and the flexoelectric effect is investigated by using interfacial voltage detection. By introducing hydrated structures into liquids, a significant enlargement of the flexoelectric coefficient up to 2.3 × 10−9 C m−1 is obtained in Fe2(SO4)3 solution by four times than DI water. These findings highlight the remarkable electromechanical properties of liquid materials with hydrated ions and suggest promising avenues for the application of liquid dielectrics in hydrovoltaic technology, ionotronic devices, and energy harvesters.
挠电效应是由应变梯度引入极化的机电耦合效应，在介电材料中十分普遍。然而，其在低粘度液体中的应用一直受到挠电系数尺度的限制。本研究通过一系列实验探索了各种水合离子溶液的挠电系数。此外，还利用界面电压检测法研究了离子吸附与挠电效应之间的相互作用。通过在液体中引入水合结构，Fe2(SO4)3 溶液中的挠电系数显著增大至 2.3 × 10-9 C m-1，是去离子水的四倍。这些发现凸显了含有水合离子的液体材料的卓越机电特性，并为液体电介质在水伏特技术、离子电子器件和能量收集器中的应用提供了前景广阔的途径。
{"title":"Enhanced flexoelectricity of liquid with hydrated ions","authors":"Yifan Li, Yanyu Li, Xingjian Feng, Chongpu Zhai, Shuwen Zhang and Minglong Xu","doi":"10.1088/1361-6463/ad632f","DOIUrl":"https://doi.org/10.1088/1361-6463/ad632f","url":null,"abstract":"Flexoelectricity, denoted as an electromechanical coupling effect from strain gradient introduced polarization, is prevalent in dielectric materials. However, its application in low-viscosity liquids has been limited by the scale of the flexoelectric coefficient. This study explores the flexoelectric coefficient of various hydrated ion solutions through a series of experiments. Additionally, the interplay between ion adsorption and the flexoelectric effect is investigated by using interfacial voltage detection. By introducing hydrated structures into liquids, a significant enlargement of the flexoelectric coefficient up to 2.3 × 10−9 C m−1 is obtained in Fe2(SO4)3 solution by four times than DI water. These findings highlight the remarkable electromechanical properties of liquid materials with hydrated ions and suggest promising avenues for the application of liquid dielectrics in hydrovoltaic technology, ionotronic devices, and energy harvesters.","PeriodicalId":16789,"journal":{"name":"Journal of Physics D: Applied Physics","volume":"1 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141753991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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