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Ye Zhang,1 Xiaoli Tan,2 Shiyu Hu,3 Zhifang Cui,4 Wenyu Chen2 1Department of General Medicine, Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang, People’s Republic of China; 2Department of Respiratory Medicine, Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang, People’s Republic of China; 3Jiaxing University Master Degree Cultivation Base, Zhejiang Chinese Medical University, Jiaxing, Zhejiang, People’s Republic of China; 4Department of Respiratory Medicine, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, People’s Republic of ChinaCorrespondence: Wenyu Chen, Department of Respiratory Medicine, Affiliated Hospital of Jiaxing University, No. 1882, Zhonghuan South Road, Nanhu District, Jiaxing City, Zhejiang Province, 314001, People’s Republic of China, Email 00135116@zjxu.edu.cnPurpose: Chronic obstructive pulmonary disease (COPD) concurrent with respiratory failure (RF) is devastating, and may result in death and disability. Systemic immune-inflammation index (SII) is a new prognostic biomarker linked to unfavorable outcomes of acute coronary syndrome, ischemic stroke, and heart failure. Nonetheless, its role in COPD is rarely investigated. Consequently, this study intends to assess the accuracy of SII in predicting the prognosis of COPD.Patients and Methods: The clinical information was retrospectively acquired from the Medical Information Mart for Intensive Care-IV database. The outcomes encompassed the incidence of RF and mortality. The relationship between different SII and outcomes was examined utilizing the Cox proportional-hazards model and restricted cubic splines. Kaplan-Meier analysis was employed for all-cause mortality.Results: The present study incorporated 1653 patients. During hospitalization, 697 patients (42.2%) developed RF, and 169 patients (10.2%) died. And 637 patients (38.5%) died during long-term follow-up. Higher SII increased the risk of RF (RF: HR: 1.19, 95% CI 1.12– 1.28, P< 0.001)

Domain wall motion in ferroics, similar to dislocation motion in metals, can be tuned by well‐concepted microstructural elements. In demanding high‐power applications of piezoelectric materials, the domain wall motion is considered as a lossy hysteretic mechanism that should be restricted. Current applications for so‐called hard piezoelectrics are abundant and hinge on the use of an acceptor‐doping scheme. However, this mechanism features severe limitations due to enhanced mobility of oxygen vacancies at moderate temperatures. By analogy with metal technology, the authors present here a new solution for electroceramics, where precipitates are utilized to pin domain walls and improve piezoelectric properties. Through a sequence of sintering, nucleation, and precipitate growth, intragranular precipitates leading to a fine domain structure are developed as shown by transmission electron microscopy, piezoresponse force microscopy, and phase‐field simulation. This structure impedes the domain wall motion as elucidated by electromechanical characterization. As a result, the mechanical quality factor is increased by ≈50% and the hysteresis in electrostrain is suppressed considerably. This is even achieved with slightly increased piezoelectric coefficient and electromechanical coupling factor. This novel process can be smoothly implemented in industrial production processes and is accessible to simple laboratory experimentation for microstructure optimization and implementation in various ferroelectric systems.

Domain wall motion in ferroics, similar to dislocation motion in metals, can be tuned by well‐concepted microstructural elements. In demanding high‐power applications of piezoelectric materials, the domain wall motion is considered as a lossy hysteretic mechanism that should be restricted. Current applications for so‐called hard piezoelectrics are abundant and hinge on the use of an acceptor‐doping scheme. However, this mechanism features severe limitations due to enhanced mobility of oxygen vacancies at moderate temperatures. By analogy with metal technology, the authors present here a new solution for electroceramics, where precipitates are utilized to pin domain walls and improve piezoelectric properties. Through a sequence of sintering, nucleation, and precipitate growth, intragranular precipitates leading to a fine domain structure are developed as shown by transmission electron microscopy, piezoresponse force microscopy, and phase‐field simulation. This structure impedes the domain wall motion as elucidated by electromechanical characterization. As a result, the mechanical quality factor is increased by ≈50% and the hysteresis in electrostrain is suppressed considerably. This is even achieved with slightly increased piezoelectric coefficient and electromechanical coupling factor. This novel process can be smoothly implemented in industrial production processes and is accessible to simple laboratory experimentation for microstructure optimization and implementation in various ferroelectric systems.

Domain wall motion in ferroics, similar to dislocation motion in metals, can be tuned by well‐concepted microstructural elements. In demanding high‐power applications of piezoelectric materials, the domain wall motion is considered as a lossy hysteretic mechanism that should be restricted. Current applications for so‐called hard piezoelectrics are abundant and hinge on the use of an acceptor‐doping scheme. However, this mechanism features severe limitations due to enhanced mobility of oxygen vacancies at moderate temperatures. By analogy with metal technology, the authors present here a new solution for electroceramics, where precipitates are utilized to pin domain walls and improve piezoelectric properties. Through a sequence of sintering, nucleation, and precipitate growth, intragranular precipitates leading to a fine domain structure are developed as shown by transmission electron microscopy, piezoresponse force microscopy, and phase‐field simulation. This structure impedes the domain wall motion as elucidated by electromechanical characterization. As a result, the mechanical quality factor is increased by ≈50% and the hysteresis in electrostrain is suppressed considerably. This is even achieved with slightly increased piezoelectric coefficient and electromechanical coupling factor. This novel process can be smoothly implemented in industrial production processes and is accessible to simple laboratory experimentation for microstructure optimization and implementation in various ferroelectric systems.

Domain wall motion in ferroics, similar to dislocation motion in metals, can be tuned by well‐concepted microstructural elements. In demanding high‐power applications of piezoelectric materials, the domain wall motion is considered as a lossy hysteretic mechanism that should be restricted. Current applications for so‐called hard piezoelectrics are abundant and hinge on the use of an acceptor‐doping scheme. However, this mechanism features severe limitations due to enhanced mobility of oxygen vacancies at moderate temperatures. By analogy with metal technology, the authors present here a new solution for electroceramics, where precipitates are utilized to pin domain walls and improve piezoelectric properties. Through a sequence of sintering, nucleation, and precipitate growth, intragranular precipitates leading to a fine domain structure are developed as shown by transmission electron microscopy, piezoresponse force microscopy, and phase‐field simulation. This structure impedes the domain wall motion as elucidated by electromechanical characterization. As a result, the mechanical quality factor is increased by ≈50% and the hysteresis in electrostrain is suppressed considerably. This is even achieved with slightly increased piezoelectric coefficient and electromechanical coupling factor. This novel process can be smoothly implemented in industrial production processes and is accessible to simple laboratory experimentation for microstructure optimization and implementation in various ferroelectric systems.

High‐power piezoelectric applications are predicted to share approximately one‐third of the lead‐free piezoelectric ceramic market in 2024 with alkaline niobates as the primary competitor. To suppress self‐heating in high‐power devices due to mechanical loss when driven by large electric fields, piezoelectric hardening to restrict domain wall motion is required. In the present work, highly effective piezoelectric hardening via coherent plate‐like precipitates in a model system of the (Li,Na)NbO₃ (LNN) solid solution delivers a reduction in losses, quantified as an electromechanical quality factor, by a factor of ten. Various thermal aging schemes are demonstrated to control the average size, number density, and location of the precipitates. The established properties are correlated with a detailed determination of short‐ and long‐range atomic structure by X‐ray diffraction and pair distribution function analysis, respectively, as well as microstructure determined by transmission electron microscopy. The impact of microstructure with precipitates on both small‐ and large‐field properties is also established. These results pave the way to implement precipitate hardening in piezoelectric materials, analogous to precipitate hardening in metals, broadening their use cases in applications.

High‐power piezoelectric applications are predicted to share approximately one‐third of the lead‐free piezoelectric ceramic market in 2024 with alkaline niobates as the primary competitor. To suppress self‐heating in high‐power devices due to mechanical loss when driven by large electric fields, piezoelectric hardening to restrict domain wall motion is required. In the present work, highly effective piezoelectric hardening via coherent plate‐like precipitates in a model system of the (Li,Na)NbO₃ (LNN) solid solution delivers a reduction in losses, quantified as an electromechanical quality factor, by a factor of ten. Various thermal aging schemes are demonstrated to control the average size, number density, and location of the precipitates. The established properties are correlated with a detailed determination of short‐ and long‐range atomic structure by X‐ray diffraction and pair distribution function analysis, respectively, as well as microstructure determined by transmission electron microscopy. The impact of microstructure with precipitates on both small‐ and large‐field properties is also established. These results pave the way to implement precipitate hardening in piezoelectric materials, analogous to precipitate hardening in metals, broadening their use cases in applications.

High‐power piezoelectric applications are predicted to share approximately one‐third of the lead‐free piezoelectric ceramic market in 2024 with alkaline niobates as the primary competitor. To suppress self‐heating in high‐power devices due to mechanical loss when driven by large electric fields, piezoelectric hardening to restrict domain wall motion is required. In the present work, highly effective piezoelectric hardening via coherent plate‐like precipitates in a model system of the (Li,Na)NbO₃ (LNN) solid solution delivers a reduction in losses, quantified as an electromechanical quality factor, by a factor of ten. Various thermal aging schemes are demonstrated to control the average size, number density, and location of the precipitates. The established properties are correlated with a detailed determination of short‐ and long‐range atomic structure by X‐ray diffraction and pair distribution function analysis, respectively, as well as microstructure determined by transmission electron microscopy. The impact of microstructure with precipitates on both small‐ and large‐field properties is also established. These results pave the way to implement precipitate hardening in piezoelectric materials, analogous to precipitate hardening in metals, broadening their use cases in applications.

Dislocations are usually expected to degrade electrical, thermal and optical functionality and to tune mechanical properties of materials. Here, we demonstrate a general framework for the control of dislocation–domain wall interactions in ferroics, employing an imprinted dislocation network. Anisotropic dielectric and electromechanical properties are engineered in barium titanate crystals via well-controlled line-plane relationships, culminating in extraordinary and stable large-signal dielectric permittivity (≈23100) and piezoelectric coefficient (≈2470 pm V–1). In contrast, a related increase in properties utilizing point-plane relation prompts a dramatic cyclic degradation. Observed dielectric and piezoelectric properties are rationalized using transmission electron microscopy and time- and cycle-dependent nuclear magnetic resonance paired with X-ray diffraction. Succinct mechanistic understanding is provided by phase-field simulations and driving force calculations of the described dislocation–domain wall interactions. Our 1D-2D defect approach offers a fertile ground for tailoring functionality in a wide range of functional material systems.

Dislocations are usually expected to degrade electrical, thermal and optical functionality and to tune mechanical properties of materials. Here, we demonstrate a general framework for the control of dislocation–domain wall interactions in ferroics, employing an imprinted dislocation network. Anisotropic dielectric and electromechanical properties are engineered in barium titanate crystals via well-controlled line-plane relationships, culminating in extraordinary and stable large-signal dielectric permittivity (≈23100) and piezoelectric coefficient (≈2470 pm V–1). In contrast, a related increase in properties utilizing point-plane relation prompts a dramatic cyclic degradation. Observed dielectric and piezoelectric properties are rationalized using transmission electron microscopy and time- and cycle-dependent nuclear magnetic resonance paired with X-ray diffraction. Succinct mechanistic understanding is provided by phase-field simulations and driving force calculations of the described dislocation–domain wall interactions. Our 1D-2D defect approach offers a fertile ground for tailoring functionality in a wide range of functional material systems., RST/Storage of Electrochemical Energy

2019 Elsevier Ltd Lead-free (K0.5Na0.5)NbO3-based (KNN) piezoceramics featuring a polymorphic phase boundary (PPB) between the orthorhombic and tetragonal phases at room temperature are reported to possess high piezoelectric properties but with inferior cycling stability, while the ceramics with a single tetragonal phase show improved cycling stability but with lower piezoelectric coefficients. In this work, electric biasing in-situ transmission electron microscopy (TEM) study is conducted on two KNN-based compositions, which are respectively at and off PPB. Our observations reveal the distinctive domain responses in these two ceramics under cyclic fields. The higher domain wall density in the poled KNN at PPB contributes to the high piezoelectric properties. Upon cycling, however, a new microstructure feature, "domain intersection", is directly observed in this PPB composition. In comparison, the off-PPB KNN ceramic develops large domains during poling, which experience much less extent of disruption during cycling. Our comparative study provides the basis for understanding the relation between phase composition and piezoelectric performance.

© 2020 Following increased environmental concerns on the toxicity of lead, the discovery of ultrahigh piezoelectricity in lead-free piezoelectric materials is critical for the substitution of commercial lead zirconate titanate (PZT) ceramics in numerous electronic devices. In this work, a synergistic design strategy is proposed to enhance the piezoelectricity in lead-free piezoelectric materials by flattening the Gibbs free energy density profile, via the coexistence of multiple phases and local structural heterogeneity. This strategic material design approach is based on first-principles calculations combined with Landau phenomenological theory and phase field simulations. Sustainable Stannum-doped BaTiO3 lead-free ferroelectric ceramics are prepared to validate our proposed mechanism, and a giant piezoelectric coefficient d33 > 1100 pC/N is achieved, being the highest value reported in lead-free piezoceramics. The mechanism and paradigm of the excellent piezoelectricity achieved here provides a feasible solution for replacing lead-based piezoelectrics by lead-free counterparts.

© 2020 Following increased environmental concerns on the toxicity of lead, the discovery of ultrahigh piezoelectricity in lead-free piezoelectric materials is critical for the substitution of commercial lead zirconate titanate (PZT) ceramics in numerous electronic devices. In this work, a synergistic design strategy is proposed to enhance the piezoelectricity in lead-free piezoelectric materials by flattening the Gibbs free energy density profile, via the coexistence of multiple phases and local structural heterogeneity. This strategic material design approach is based on first-principles calculations combined with Landau phenomenological theory and phase field simulations. Sustainable Stannum-doped BaTiO3 lead-free ferroelectric ceramics are prepared to validate our proposed mechanism, and a giant piezoelectric coefficient d33 > 1100 pC/N is achieved, being the highest value reported in lead-free piezoceramics. The mechanism and paradigm of the excellent piezoelectricity achieved here provides a feasible solution for replacing lead-based piezoelectrics by lead-free counterparts.

2019 Elsevier Ltd Lead-free (K0.5Na0.5)NbO3-based (KNN) piezoceramics featuring a polymorphic phase boundary (PPB) between the orthorhombic and tetragonal phases at room temperature are reported to possess high piezoelectric properties but with inferior cycling stability, while the ceramics with a single tetragonal phase show improved cycling stability but with lower piezoelectric coefficients. In this work, electric biasing in-situ transmission electron microscopy (TEM) study is conducted on two KNN-based compositions, which are respectively at and off PPB. Our observations reveal the distinctive domain responses in these two ceramics under cyclic fields. The higher domain wall density in the poled KNN at PPB contributes to the high piezoelectric properties. Upon cycling, however, a new microstructure feature, "domain intersection", is directly observed in this PPB composition. In comparison, the off-PPB KNN ceramic develops large domains during poling, which experience much less extent of disruption during cycling. Our comparative study provides the basis for understanding the relation between phase composition and piezoelectric performance.

2019 Elsevier Ltd Lead-free (K0.5Na0.5)NbO3-based (KNN) piezoceramics featuring a polymorphic phase boundary (PPB) between the orthorhombic and tetragonal phases at room temperature are reported to possess high piezoelectric properties but with inferior cycling stability, while the ceramics with a single tetragonal phase show improved cycling stability but with lower piezoelectric coefficients. In this work, electric biasing in-situ transmission electron microscopy (TEM) study is conducted on two KNN-based compositions, which are respectively at and off PPB. Our observations reveal the distinctive domain responses in these two ceramics under cyclic fields. The higher domain wall density in the poled KNN at PPB contributes to the high piezoelectric properties. Upon cycling, however, a new microstructure feature, "domain intersection", is directly observed in this PPB composition. In comparison, the off-PPB KNN ceramic develops large domains during poling, which experience much less extent of disruption during cycling. Our comparative study provides the basis for understanding the relation between phase composition and piezoelectric performance.

© 2020 Following increased environmental concerns on the toxicity of lead, the discovery of ultrahigh piezoelectricity in lead-free piezoelectric materials is critical for the substitution of commercial lead zirconate titanate (PZT) ceramics in numerous electronic devices. In this work, a synergistic design strategy is proposed to enhance the piezoelectricity in lead-free piezoelectric materials by flattening the Gibbs free energy density profile, via the coexistence of multiple phases and local structural heterogeneity. This strategic material design approach is based on first-principles calculations combined with Landau phenomenological theory and phase field simulations. Sustainable Stannum-doped BaTiO3 lead-free ferroelectric ceramics are prepared to validate our proposed mechanism, and a giant piezoelectric coefficient d33 > 1100 pC/N is achieved, being the highest value reported in lead-free piezoceramics. The mechanism and paradigm of the excellent piezoelectricity achieved here provides a feasible solution for replacing lead-based piezoelectrics by lead-free counterparts.

© 2020 Following increased environmental concerns on the toxicity of lead, the discovery of ultrahigh piezoelectricity in lead-free piezoelectric materials is critical for the substitution of commercial lead zirconate titanate (PZT) ceramics in numerous electronic devices. In this work, a synergistic design strategy is proposed to enhance the piezoelectricity in lead-free piezoelectric materials by flattening the Gibbs free energy density profile, via the coexistence of multiple phases and local structural heterogeneity. This strategic material design approach is based on first-principles calculations combined with Landau phenomenological theory and phase field simulations. Sustainable Stannum-doped BaTiO3 lead-free ferroelectric ceramics are prepared to validate our proposed mechanism, and a giant piezoelectric coefficient d33 > 1100 pC/N is achieved, being the highest value reported in lead-free piezoceramics. The mechanism and paradigm of the excellent piezoelectricity achieved here provides a feasible solution for replacing lead-based piezoelectrics by lead-free counterparts.

2019 Elsevier Ltd Lead-free (K0.5Na0.5)NbO3-based (KNN) piezoceramics featuring a polymorphic phase boundary (PPB) between the orthorhombic and tetragonal phases at room temperature are reported to possess high piezoelectric properties but with inferior cycling stability, while the ceramics with a single tetragonal phase show improved cycling stability but with lower piezoelectric coefficients. In this work, electric biasing in-situ transmission electron microscopy (TEM) study is conducted on two KNN-based compositions, which are respectively at and off PPB. Our observations reveal the distinctive domain responses in these two ceramics under cyclic fields. The higher domain wall density in the poled KNN at PPB contributes to the high piezoelectric properties. Upon cycling, however, a new microstructure feature, "domain intersection", is directly observed in this PPB composition. In comparison, the off-PPB KNN ceramic develops large domains during poling, which experience much less extent of disruption during cycling. Our comparative study provides the basis for understanding the relation between phase composition and piezoelectric performance.

Piezoelectric materials convert between electrical and mechanical energies such that an applied stress induces a polarization and an applied electric field induces a strain. This review describes the fundamental mechanisms governing the piezoelectric response in high-performance piezoelectric single crystals, ceramics, and thin films. While there are a number of useful piezoelectric small molecules and polymers, the article focuses on inorganic materials displaying the piezoelectric effect. Piezoelectricity is first defined, and the mechanisms that contribute are discussed in terms of the key crystal structures for materials with large piezoelectric coefficients. Exemplar systems are then discussed and compared for the cases of single crystals, bulk ceramics, and thin films.

Piezoelectric materials convert between electrical and mechanical energies such that an applied stress induces a polarization and an applied electric field induces a strain. This review describes the fundamental mechanisms governing the piezoelectric response in high-performance piezoelectric single crystals, ceramics, and thin films. While there are a number of useful piezoelectric small molecules and polymers, the article focuses on inorganic materials displaying the piezoelectric effect. Piezoelectricity is first defined, and the mechanisms that contribute are discussed in terms of the key crystal structures for materials with large piezoelectric coefficients. Exemplar systems are then discussed and compared for the cases of single crystals, bulk ceramics, and thin films.

Ripening of the model fruit tomato (Solanum lycopersicum) is controlled by a transcription factor network including NAC (NAM, ATAF1/2, and CUC2) domain proteins such as No-ripening (NOR), SlNAC1, and SlNAC4, but very little is known about the NAC targets or how they regulate ripening. Here, we conducted a systematic search of fruit-expressed NAC genes and showed that silencing NOR-like1 (Solyc07g063420) using virus-induced gene silencing (VIGS) inhibited specific aspects of ripening. Ripening initiation was delayed by 14 days when NOR-like1 function was inactivated by CRISPR/Cas9 and fruits showed obviously reduced ethylene production, retarded softening and chlorophyll loss, and reduced lycopene accumulation. RNA-sequencing profiling and gene promoter analysis suggested that genes involved in ethylene biosynthesis (SlACS2, SlACS4), color formation (SlGgpps2, SlSGR1), and cell wall metabolism (SlPG2a, SlPL, SlCEL2, and SlEXP1) are direct targets of NOR-like1. Electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR), and dual-luciferase reporter assay (DLR) confirmed that NOR-like1 bound to the promoters of these genes both in vitro and in vivo, and activated their expression. Our findings demonstrate that NOR-like1 is a new positive regulator of tomato fruit ripening, with an important role in the transcriptional regulatory network.

Piezoelectric materials convert between electrical and mechanical energies such that an applied stress induces a polarization and an applied electric field induces a strain. This review describes the fundamental mechanisms governing the piezoelectric response in high-performance piezoelectric single crystals, ceramics, and thin films. While there are a number of useful piezoelectric small molecules and polymers, the article focuses on inorganic materials displaying the piezoelectric effect. Piezoelectricity is first defined, and the mechanisms that contribute are discussed in terms of the key crystal structures for materials with large piezoelectric coefficients. Exemplar systems are then discussed and compared for the cases of single crystals, bulk ceramics, and thin films.

Piezoelectric materials convert between electrical and mechanical energies such that an applied stress induces a polarization and an applied electric field induces a strain. This review describes the fundamental mechanisms governing the piezoelectric response in high-performance piezoelectric single crystals, ceramics, and thin films. While there are a number of useful piezoelectric small molecules and polymers, the article focuses on inorganic materials displaying the piezoelectric effect. Piezoelectricity is first defined, and the mechanisms that contribute are discussed in terms of the key crystal structures for materials with large piezoelectric coefficients. Exemplar systems are then discussed and compared for the cases of single crystals, bulk ceramics, and thin films.

In this work, we report an experimental technique with nanometer resolution to reveal the microstructural mechanism for electric fatigue in ferroelectrics. The electric field in situ transmission electron microscopy (TEM) was used to directly visualize the domain evolution during the fatigue process in a 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 ceramic. The structure-property relationship was well demonstrated by combining the microscopic observations with corresponding dielectric, piezoelectric, and ferroelectric properties measured on bulk specimens. It was found that the domain switching capability was substantially suppressed after 103 cycles of bipolar fields, leading to an immobilized domain configuration thereafter. Correspondingly, a pronounced degradation of the functionality of the ceramic was manifested, accompanying with a coercive field bumping and polarization current density peak broadening. The reduction of the polarization, dielectric constant, and piezoelectric coefficient were found to follow a power-law relation. Seed inhibition mechanism was suggested to be responsible for the observed fatigue behaviors

In this work, we report an experimental technique with nanometer resolution to reveal the microstructural mechanism for electric fatigue in ferroelectrics. The electric field in situ transmission electron microscopy (TEM) was used to directly visualize the domain evolution during the fatigue process in a 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 ceramic. The structure-property relationship was well demonstrated by combining the microscopic observations with corresponding dielectric, piezoelectric, and ferroelectric properties measured on bulk specimens. It was found that the domain switching capability was substantially suppressed after 103 cycles of bipolar fields, leading to an immobilized domain configuration thereafter. Correspondingly, a pronounced degradation of the functionality of the ceramic was manifested, accompanying with a coercive field bumping and polarization current density peak broadening. The reduction of the polarization, dielectric constant, and piezoelectric coefficient were found to follow a power-law relation. Seed inhibition mechanism was suggested to be responsible for the observed fatigue behaviors

The microstructural origin of the exceptionally high piezoelectric response of polycrystalline 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is investigated using in situ transmission electron microscopy, in addition to a wide variety of bulk measurements and first-principles calculations. A direct correlation is established relating a domain wall-free state to the ultrahigh piezoelectric d33 coefficient in this BaTiO3-based composition. The results suggest that the unique single-domain state formed during electrical poling is a result of a structural transition from coexistent rhombohedral and tetragonal phases to an orthorhombic phase that has an anomalously low elastic modulus. First-principles calculations indicate that incorporating Ca2+ and Zr4+ into BaTiO3 reduces the differences in structure and energy of the variant perovskite phases, and 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is identified as unique because the variant phases become almost indistinguishable. The structural instability and elastic softening observed here are responsible for the excellent piezoelectric properties of this lead-free ceramic. 2014 American Physical Society.

The microstructural origin of the exceptionally high piezoelectric response of polycrystalline 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is investigated using in situ transmission electron microscopy, in addition to a wide variety of bulk measurements and first-principles calculations. A direct correlation is established relating a domain wall-free state to the ultrahigh piezoelectric d33 coefficient in this BaTiO3-based composition. The results suggest that the unique single-domain state formed during electrical poling is a result of a structural transition from coexistent rhombohedral and tetragonal phases to an orthorhombic phase that has an anomalously low elastic modulus. First-principles calculations indicate that incorporating Ca2+ and Zr4+ into BaTiO3 reduces the differences in structure and energy of the variant perovskite phases, and 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is identified as unique because the variant phases become almost indistinguishable. The structural instability and elastic softening observed here are responsible for the excellent piezoelectric properties of this lead-free ceramic. 2014 American Physical Society.

The microstructural origin of the exceptionally high piezoelectric response of polycrystalline 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is investigated using in situ transmission electron microscopy, in addition to a wide variety of bulk measurements and first-principles calculations. A direct correlation is established relating a domain wall-free state to the ultrahigh piezoelectric d33 coefficient in this BaTiO3-based composition. The results suggest that the unique single-domain state formed during electrical poling is a result of a structural transition from coexistent rhombohedral and tetragonal phases to an orthorhombic phase that has an anomalously low elastic modulus. First-principles calculations indicate that incorporating Ca2+ and Zr4+ into BaTiO3 reduces the differences in structure and energy of the variant perovskite phases, and 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is identified as unique because the variant phases become almost indistinguishable. The structural instability and elastic softening observed here are responsible for the excellent piezoelectric properties of this lead-free ceramic. 2014 American Physical Society.

The microstructural origin of the exceptionally high piezoelectric response of polycrystalline 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is investigated using in situ transmission electron microscopy, in addition to a wide variety of bulk measurements and first-principles calculations. A direct correlation is established relating a domain wall-free state to the ultrahigh piezoelectric d33 coefficient in this BaTiO3-based composition. The results suggest that the unique single-domain state formed during electrical poling is a result of a structural transition from coexistent rhombohedral and tetragonal phases to an orthorhombic phase that has an anomalously low elastic modulus. First-principles calculations indicate that incorporating Ca2+ and Zr4+ into BaTiO3 reduces the differences in structure and energy of the variant perovskite phases, and 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is identified as unique because the variant phases become almost indistinguishable. The structural instability and elastic softening observed here are responsible for the excellent piezoelectric properties of this lead-free ceramic. 2014 American Physical Society.

Chemically modified (K0.5Na0.5)NbO3 compositions with finely tuned polymorphic phase boundaries (PPBs) have shown excellent piezoelectric properties. The evolution of the domain morphology and crystal structure under applied electric fields of a model material, 0.948(K0.5Na0.5)NbO3-0.052LiSbO3, was directly visualized using in situ transmission electron microscopy. The in situ observations correlate extremely well with measurements of the electromechanical response on bulk samples. It is found that the origin of the excellent piezoelectric performance in this lead-free composition is due to a tilted monoclinic phase that emerges from the PPB when poling fields greater than 14 kV/cm are applied. 2013 AIP Publishing LLC.

Chemically modified (K0.5Na0.5)NbO3 compositions with finely tuned polymorphic phase boundaries (PPBs) have shown excellent piezoelectric properties. The evolution of the domain morphology and crystal structure under applied electric fields of a model material, 0.948(K0.5Na0.5)NbO3-0.052LiSbO3, was directly visualized using in situ transmission electron microscopy. The in situ observations correlate extremely well with measurements of the electromechanical response on bulk samples. It is found that the origin of the excellent piezoelectric performance in this lead-free composition is due to a tilted monoclinic phase that emerges from the PPB when poling fields greater than 14 kV/cm are applied. 2013 AIP Publishing LLC.

Nanocomposite materials offer a vast design-space of potential material properties, depending on the properties of the constituents and their spatial arrangement. Nanocomposites of polymer/nanoparticle, formed by incorporating nanoparticles into a polymer matrix, have received a great deal of research interest from the scientific community because of the potential performance enhancement relative to either of the non-hybrid constituents. This 36 month effort has led to three major accomplishments: (1) synthesized novel nanostructured composites (i.e., nanocomposites incorporating ferroelectric nanoparticles and SPIONs intimately and permanently capped with polymers on the surface); (2) characterized the nanocomposites developed under 1 by measuring their dielectric and magnetic properties as a function of temperature and frequency; and (3) modeled the dielectric and magnetic properties of the nanocomposites in terms of the electromagnetic parameters and spatial arrangement of the constituents in order to facilitate design of materials with specified properties. The potential benefits of employing ferroelectric and magnetic materials in nanocomposites are manifested not only in the number of applications (e.g., sensors, spintronics devices, capacitors, actuators, transducers, etc.) that are anticipated to fill a critical need in future military, but also in the gaining of fundamental knowledge and expertise on the structure-property relationships in these novel nanostructured materials., Prepared in cooperation with Iowa State Univ., Ames, IA, Department of Materials Science and Engineering.

This project has developed a statistical learning approach to identify potential new high temperature ferroelectric piezoelectric perovskite compounds. Our predictions of the Curie temperature (Tc) ranging from 700C-1100C are the highest reported in either experimental or theoretical studies and the number of new proposed compounds based on our work nearly doubles the known candidate piezoelectric ferroelectric perovskites. Unlike most computational studies on crystal chemistry, where the starting point is some form of electronic structure calculation, we use a data driven approach to initiate our search. In parallel to the computational studies, we have developed a detailed experimental protocol for exploring the processing parameter space for synthesizing in a combinatorial fashion of known existing piezoelectric perovskites. We not only identified new compound chemistries with TC exceeding known ferroelectric perovskite materials but also optimized the site occupancy of newly the identified new compound chemistries. This provides strong evidence of the value of informatics to significantly accelerate materials discovery. Our experimental studies also provided us the framework to test our informatics based predictions. For instance we have synthesized BiLuO3-PbTiO3 and discovered that the system is indeed a perovskite structure as per our predictions and our measured Tc of 550C though lower than the 700C of our predictions, is one of the highest reported experimental measurements reported in the literature. Given that our models are based solely on crystal and electronic structure data and did not microstructural or impurity chemistry information, this is a very promising result. To the best of our knowledge, this is the first direct attempt to experimentally validate informatics based structure-property predictions., The original document contains color images.

Batch experiments were conducted to elucidate the adsorption of Pb(II) and three types of widely used surfactants (sodium dodecylbenzene sulfonate (SDBS), octyl-phenol-ethoxylate (TX-100), and benzalkonium chloride (BKC)) from aqueous solutions by using oxidized multiwall carbon nanotubes (OMWCNTs). The effect of each kind of surfactant on the adsorption of Pb(II) and vice versa were studied in detail. The results indicated that the pH values affected the adsorption of Pb(II). TX-100 and BKC to OMWCNTs dramatically, whereas the adsorption of SDBS was almost pH-independent at pH < 9 and then decreased with increasing pH at pH > 9. The adsorption of Pb(II) was enhanced obviously by the presence of SDBS, but slightly inhibited by the presence of BKC. The adsorption of Pb(II) can be well described by Langmuir model. The adsorption process in the Pb-surfactant-OMWCNT ternary system was attributed to electrostatic, hydrophobic and pi-pi interactions. XPS analysis showed that the adsorption mechanism was mainly due to chemical interaction between Pb(II) and the surface functional groups of OMWCNTs and the surfactants. (C) 2010 Elsevier B.V. All rights reserved.

(K,Na)NbO 3 (KNN) lead-free ceramics were fabricated using conventional solid-state reaction method. The domain configurations were studied with transmission electron microscopy and found to be closely related to the sintering temperature and cooling rate. High density ceramics with uniform compositions were obtained when sintered at 1200°C with a slow cooling rate, resulting in the improved piezoelectric properties, with d 33 on the order of 150-160 pC/N, which is comparable to the hot pressed KNN ceramics. The microstructures of the ceramics synthesized at various conditions were explained in terms of the solid-solution characteristics of KNN system, based on the high temperature phase diagram. The relationship of processing parameter- microstructure-property established herein will lead to further improvements in the piezoelectric properties of KNN lead-free materials. 2011 The American Ceramic Society.

(K,Na)NbO 3 (KNN) lead-free ceramics were fabricated using conventional solid-state reaction method. The domain configurations were studied with transmission electron microscopy and found to be closely related to the sintering temperature and cooling rate. High density ceramics with uniform compositions were obtained when sintered at 1200°C with a slow cooling rate, resulting in the improved piezoelectric properties, with d 33 on the order of 150-160 pC/N, which is comparable to the hot pressed KNN ceramics. The microstructures of the ceramics synthesized at various conditions were explained in terms of the solid-solution characteristics of KNN system, based on the high temperature phase diagram. The relationship of processing parameter- microstructure-property established herein will lead to further improvements in the piezoelectric properties of KNN lead-free materials. 2011 The American Ceramic Society.

Batch experiments were conducted to elucidate the adsorption of Pb(II) and three types of widely used surfactants (sodium dodecylbenzene sulfonate (SDBS), octyl-phenol-ethoxylate (TX-100), and benzalkonium chloride (BKC)) from aqueous solutions by using oxidized multiwall carbon nanotubes (OMWCNTs). The effect of each kind of surfactant on the adsorption of Pb(II) and vice versa were studied in detail. The results indicated that the pH values affected the adsorption of Pb(II). TX-100 and BKC to OMWCNTs dramatically, whereas the adsorption of SDBS was almost pH-independent at pH < 9 and then decreased with increasing pH at pH > 9. The adsorption of Pb(II) was enhanced obviously by the presence of SDBS, but slightly inhibited by the presence of BKC. The adsorption of Pb(II) can be well described by Langmuir model. The adsorption process in the Pb-surfactant-OMWCNT ternary system was attributed to electrostatic, hydrophobic and pi-pi interactions. XPS analysis showed that the adsorption mechanism was mainly due to chemical interaction between Pb(II) and the surface functional groups of OMWCNTs and the surfactants. (C) 2010 Elsevier B.V. All rights reserved.

Batch experiments were conducted to elucidate the adsorption of Pb(II) and three types of widely used surfactants (sodium dodecylbenzene sulfonate (SDBS), octyl-phenol-ethoxylate (TX-100), and benzalkonium chloride (BKC)) from aqueous solutions by using oxidized multiwall carbon nanotubes (OMWCNTs). The effect of each kind of surfactant on the adsorption of Pb(II) and vice versa were studied in detail. The results indicated that the pH values affected the adsorption of Pb(II). TX-100 and BKC to OMWCNTs dramatically, whereas the adsorption of SDBS was almost pH-independent at pH < 9 and then decreased with increasing pH at pH > 9. The adsorption of Pb(II) was enhanced obviously by the presence of SDBS, but slightly inhibited by the presence of BKC. The adsorption of Pb(II) can be well described by Langmuir model. The adsorption process in the Pb-surfactant-OMWCNT ternary system was attributed to electrostatic, hydrophobic and pi-pi interactions. XPS analysis showed that the adsorption mechanism was mainly due to chemical interaction between Pb(II) and the surface functional groups of OMWCNTs and the surfactants. (C) 2010 Elsevier B.V. All rights reserved.

(K,Na)NbO 3 (KNN) lead-free ceramics were fabricated using conventional solid-state reaction method. The domain configurations were studied with transmission electron microscopy and found to be closely related to the sintering temperature and cooling rate. High density ceramics with uniform compositions were obtained when sintered at 1200°C with a slow cooling rate, resulting in the improved piezoelectric properties, with d 33 on the order of 150-160 pC/N, which is comparable to the hot pressed KNN ceramics. The microstructures of the ceramics synthesized at various conditions were explained in terms of the solid-solution characteristics of KNN system, based on the high temperature phase diagram. The relationship of processing parameter- microstructure-property established herein will lead to further improvements in the piezoelectric properties of KNN lead-free materials. 2011 The American Ceramic Society.

(K,Na)NbO 3 (KNN) lead-free ceramics were fabricated using conventional solid-state reaction method. The domain configurations were studied with transmission electron microscopy and found to be closely related to the sintering temperature and cooling rate. High density ceramics with uniform compositions were obtained when sintered at 1200°C with a slow cooling rate, resulting in the improved piezoelectric properties, with d 33 on the order of 150-160 pC/N, which is comparable to the hot pressed KNN ceramics. The microstructures of the ceramics synthesized at various conditions were explained in terms of the solid-solution characteristics of KNN system, based on the high temperature phase diagram. The relationship of processing parameter- microstructure-property established herein will lead to further improvements in the piezoelectric properties of KNN lead-free materials. 2011 The American Ceramic Society.

The treatment is discussed of Ni-containing waste water, and an investigation is described into the sorption of Ni2+ on Na-rectorite as a function of contact time, temperature, pH and the presence of fulvic acid/humic acid under ambient conditions. A pseudo-second-order rate equation was used to simulate the sorption kinetics. Ni2+ removal increased with pH. The presence of FA/HA enhanced the sorption of Ni2+ at low pH values, but had little effect at high pH values. The diffuse layer model fitted very well the experimental data for Ni2+ sorption in the absence and presence of FA/HA. The Langmuir, Freundlich and Dubinin- Radushkevich models were used to simulate the sorption isotherms of Ni2+ at different temperatures. The thermodynamic data indicated that the sorption process was spontaneous and endothermic. No significant structural changes were observed to the Na-rectorite, and the sorption of N2+ mainly occurred on the surface and at the edge of the Na-rectorite., The treatment is discussed of Ni-containing waste water, and an investigation is described into the sorption of Ni2+ on Na-rectorite as a function of contact time, temperature, pH and the presence of fulvic acid/humic acid under ambient conditions. A pseudo-second-order rate equation was used to simulate the sorption kinetics. Ni2+ removal increased with pH. The presence of FA/HA enhanced the sorption of Ni2+ at low pH values, but had little effect at high pH values. The diffuse layer model fitted very well the experimental data for Ni2+ sorption in the absence and presence of FA/HA. The Langmuir, Freundlich and Dubinin- Radushkevich models were used to simulate the sorption isotherms of Ni2+ at different temperatures. The thermodynamic data indicated that the sorption process was spontaneous and endothermic. No significant structural changes were observed to the Na-rectorite, and the sorption of N2+ mainly occurred on the surface and at the edge of the Na-rectorite.