Antiferroelectric PbSnO3 Epitaxial Thin Films.

In condensed matter physics, oxide materials show various intriguing physical properties. Therefore, many efforts are made in this field to develop functional oxides. Due to the excellent potential for tin-based perovskite oxides, an expansion of new related functional compounds is crucial. This work uses a heteroepitaxial approach supported by theoretical calculation to stabilize PbSnO3 thin films with different orientations. The analyses of X-ray diffraction and transmission electron microscopy unveil the structural information. A typical antiferroelectric feature with double hysteresis and butterfly loops is observed through electrical characterizations consistent with the theoretical prediction. The phase transition is monitored, and the transition temperatures are determined based on temperature-dependent structural and electrical characterizations. Furthermore, the microscopic antiferroelectric order is noticed under atomic resolution images via scanning transmission electron microscopy. This work offers a breakthrough in synthesizing epitaxial PbSnO3 thin films and comprehensively understanding its anisotropic antiferroelectric behavior.

Synthesis of a New Ferroelectric Relaxor Based on a Combination of Antiferroelectric and Paraelectric Systems.

Relaxor ferroelectric-based energy storage systems are promising candidates for advanced applications as a result of their fast speed and high energy storage density. In the research field of ferroelectrics and relaxor ferroelectrics, the concept of solid solution is widely adopted to modify the overall properties and acquire superior performance. However, the combination between antiferroelectric and paraelectric materials was less studied and discussed. In this study, paraelectric barium hafnate (BaHfO3) and antiferroelectric lead hafnate (PbHfO3) are selected to demonstrate such a combination. A paraelectric to relaxor ferroelectric, to ferroelectric, and to antiferroelectric transition is observed by varying the composition x in the (Ba1-xPbx)HfO3 solid solution from 0 to 100%. It is noteworthy that ferroelectric phases can be realized without primal ferroelectric material. This study creates an original solid solution system with a rich spectrum of competing phases and demonstrates an approach to design relaxor ferroelectrics for energy storage applications and beyond.

A top-down strategy for amorphization of hydroxyl compounds for electrocatalytic oxygen evolution.

Amorphous materials have attracted increasing attention in diverse fields due to their unique properties, yet their controllable fabrications still remain great challenges. Here, we demonstrate a top-down strategy for the fabrications of amorphous oxides through the amorphization of hydroxides. The versatility of this strategy has been validated by the amorphizations of unitary, binary and ternary hydroxides. Detailed characterizations indicate that the amorphization process is realized by the variation of coordination environment during thermal treatment, where the M-OH octahedral structure in hydroxides evolves to M-O tetrahedral structure in amorphous oxides with the disappearance of the M-M coordination. The optimal amorphous oxide (FeCoSn(OH)6-300) exhibits superior oxygen evolution reaction (OER) activity in alkaline media, where the turnover frequency (TOF) value is 39.4 times higher than that of FeCoSn(OH)6. Moreover, the enhanced OER performance and the amorphization process are investigated with density functional theory (DFT) and molecule dynamics (MD) simulations. The reported top-down fabrication strategy for fabricating amorphous oxides, may further promote fundamental research into and practical applications of amorphous materials for catalysis.

Flexible BiVO4/WO3/ITO/Muscovite Heterostructure for Visible-Light Photoelectrochemical Photoelectrode.

Flexible electronics has recently captured extensive attention due to its intriguing functionalities and great potential for influencing our daily life. In addition, with the increasing demand for green energy, photoelectrochemical (PEC) water splitting is a clean process that directly converts solar energy to chemical energy in the form of hydrogen. Thus the development of flexible green energy electronics represents a new domain in the research field of energy harvesting. In this work, we demonstrate the BiVO4 (BVO)/WO3/ITO/muscovite heterostructure photoelectrode for water splitting with flexible characteristics. The performance of BVO was modified by specific crystal facets, and the BVO/WO3 bilayer exhibited superior performance of 33% enhanced PEC activity at 1 V vs Ag/AgCl compared with pure BVO due to the proper staggered band alignment. Moreover, excellent mechanical stability was verified by a series of bending modes. This study demonstrates a pathway to a flexible photoelectrode for developing innovative devices for solar fuel generation.

Fabrication of Large-Scale High-Mobility Flexible Transparent Zinc Oxide Single Crystal Wafers.

Single crystal wafers, such as silicon, are the fundamental carriers of advanced electronic devices. However, these wafers exhibit rigidity without mechanical flexibility, limiting their applications in flexible electronics. Here, we propose a new approach to fabricate 1.5 in. flexible functional zinc oxide (ZnO) single crystal wafers with high electron mobility (>100 cm2 V-1 s-1) and optical transparency (>80%) by a combination of thin-film deposition, a chemical solution method, and surficial treatment. The uniformity of the flexible single crystal wafers is examined by an advanced scanning X-ray diffraction technique and photoluminescence spectroscopy. The transport properties of ZnO flexible single crystal wafers retain their pristine states under various bending conditions, including cyclability and endurability. This approach demonstrates a breakthrough in the fabrication of the flexible single crystal wafers for future flexible optoelectronic applications.

Photovoltaic and flexible deep ultraviolet wavelength detector based on novel ß-Ga2O3/muscovite heteroepitaxy.

Flexible and self-powered deep ultraviolet (UV) photodetectors are pivotal for next-generation electronic skins to enrich human life quality. The fabrication of epitaxial ß-Ga2O3 thin films is challenging on flexible substrates due to high-temperature growth requirements. Herein, ß-Ga2O3 ([Formula: see text] 0 1) films are hetero-epitaxially grown on ultra-thin and environment-friendly muscovite mica which is the first time ß-Ga2O3 epitaxy growth on any flexible substrate. Integration of Gallium oxide with muscovite enables high-temperature processing as well as excellent flexibility compared to polymer substrates. Additionally, the metal-semiconductor-metal (MSM) photodetector on ß-Ga2O3 layer shows an ultra-low dark current of 800 fA at zero bias. The photovoltaic peak responsivity of 11.6 µA/W is obtained corresponding to very weak illumination of 75 µW/cm2 of 265 nm wavelength. Thermally stimulated current (TSC) measurements are employed to investigate the optically active trap states. Among these traps, trap with an activation energy of 166 meV dominates the persistence photocurrent in the devices. Finally, photovoltaic detectors have shown excellent photocurrent stability under bending induced stress up to 0.32%. Hence, this novel heteroepitaxy opens the new way for flexible deep UV photodetectors.

Dynamical Strain-Driven Phase Separation in Flexible CoFe2O4/CoO Exchange Coupling System.

Epitaxial CoFe2O4(CFO)/CoO bilayers were fabricated by pulsed laser deposition on flexible muscovite mica substrate. Samples with different CFO thicknesses were employed to study the phenomenon of exchange bias involving strongly anisotropic ferromagnet. Magnetic measurements exhibited great enhancement in the features of exchange bias. Raman and X-ray absorption spectroscopies indicated that a new phase emerged within the CFO layer because of the cation charge redistribution in CFO layer under bending, which in turn gave rise to anomalous hysteresis loops exhibited in the bent bilayers. These results provide a fundamental understanding about the mechanisms of exchange bias prevailing in these bilayers and call attention to the implementation of spintronic devices using flexible heterostructures such as the present CFO/CoO bilayers.

Transparent Flexible Heteroepitaxy of NiO Coated AZO Nanorods Arrays on Muscovites for Enhanced Energy Storage Application.

Transparent flexible energy storage devices are considered as important chains in the next-generation, which are able to store and supply energy for electronic devices. Here, aluminum-doped zinc oxide (AZO) nanorods (NRs) and nickel oxide (NiO)-coated AZO NRs on muscovites are fabricated by a radio frequency (RF) magnetron sputtering deposition method. Interestingly, AZO NRs and AZO/NiO NRs are excellent electrodes for energy storage application with high optical transparency, high conductivity, large surface area, stability under compressive and tensile strain down to a bending radius of 5 mm with 1000 bending cycles. The obtained symmetric solid-state supercapacitors based on these electrodes exhibit good performance with a large areal specific capacitance of 3.4 mF cm-2 , long cycle life 1000 times, robust mechanical properties, and high chemical stability. Furthermore, an AZO/NiO//Zn battery based on these electrodes is demonstrated, yielding a discharge capacity of 195 mAh g-1 at a current rate of 8 A g-1 and a discharge capacity of over 1000 cycles with coulombic efficiency to 92%. These results deliver a concept of opening a new opportunity for future applications in transparent flexible energy storage.

Giant Resistivity Change of Transparent ZnO/Muscovite Heteroepitaxy.

The piezoresistive effect has shown a remarkable potential for mechanical sensor applications and been sought for its excellent performance. A great attention was paid to the giant piezoresistive effect and sensitivity delivered by silicon-based nanostructures. However, low thermal stability and complicated fabrication process hinder their practical applications. To overcome these issues and enhance the functionalities, we envision the substantial piezopotential in a zinc oxide (ZnO)/muscovite (mica) heteroepitaxy system based on theoretical consideration and realize it in practice. High piezoresistive effect with giant change of resistivity (-80 to 240%) and large gauge factor (>1000) are demonstrated through mechanical bending. The detailed features of heteroepitaxy, electrical transport, and strain are probed to understand the mechanism of such a giant resistivity change. In addition, a bending model is established to reveal the distribution of strain. Finally, we demonstrate a flex sensor featuring high sensitivity, optical transparency, and two-segment sensing with a great potential toward practical applications. Such an oxide heteroepitaxy exhibits excellent piezoresistive properties and mechanical flexibility. In the near future, the importance of flex sensors will emerge because of the precise control in the automation industries, and our results lead to a new design in the field of flex sensors.

Mechanically tunable exchange coupling of Co/CoO bilayers on flexible muscovite substrates.

The employment of flexible muscovite substrates has given us the feasibility of applying strain to heterostructures dynamically by mechanical bending. In this study, this novel approach is utilized to investigate strain effects on the exchange coupling in ferromagnetic Co and anti-ferromagnetic CoO (Co/CoO) bilayers. Two different Co/CoO bilayer heterostructures were grown on muscovite substrates by oxide molecular beam epitaxy, with the CoO layer being purely (111)- and (100)-oriented. The strain-dependent exchange coupling effect can only be observed on Co/CoO(100)/mica but not on Co/CoO(111)/mica. The origin of this phenomenon is attributed to the anisotropic spin re-orientation induced by mechanical bending. The strain-dependent magnetic anisotropy of the bilayers determined by anisotropic magnetoresistance measurements confirms this conjecture. This study elucidates the fundamental understanding of how magnetic exchange coupling can be tuned by externally applied strain via mechanical bending and, hence, provides a novel approach for implementing flexible spintronic devices.

Heteroepitaxy of Co-Based Heusler Compound/Muscovite for Flexible Spintronics.

Materials with high spin-polarization play an important role in the development of spintronics. Co-based Heusler compounds are a promising candidate for practical applications because of their high Curie temperature and tunable half-metallicity. However, it is a challenge to integrate Heusler compounds into thin film heterostructures because of the lack of control on crystallinity and chemical disorder, critical factors of novel behaviors. Here, muscovite is introduced as a growth substrate to fabricate epitaxial Co2MnGa films with mechanical flexibility. The feature of heteroepitaxy is evidenced by the results of X-ray diffraction and transmission electron microscopy. Moreover, high chemical ordering with superior properties is delivered according to the observation of large Hall conductivity (680 Ω-1 cm-1) and highly saturated magnetic moment (∼3.93 µB/f.u.), matching well with bulk crystals. Furthermore, the excellence of magnetic and electrical properties is retained under the various mechanical bending conditions. Such a result suggests that the development of Co2MnGa/muscovite heteroepitaxy provides not only a pathway to the thin film heterostructure based on high-quality Heusler compounds but also a new aspect of spintronic applications on flexible substrates.

Oxide Heteroepitaxy-Based Flexible Ferroelectric Transistor.

With the rise of Internet of Things, the presence of flexible devices has attracted significant attention owing to design flexibility. A ferroelectric field-effect transistor (FeFET), showing the advantages of high speed, nondestructive readout, and low-power consumption, plays a key role in next-generation technology. However, the performance of these devices is restricted since conventional flexible substrates show poor thermal stability to integrate traditional ferroelectric materials, limiting the compatibility of wearable devices. In this study, we adopt flexible muscovite mica as a substrate due to its good thermal properties and epitaxial integration ability. A flexible FeFET composed of oxide heteroepitaxy on muscovite is realized by combining an aluminum-doped zinc oxide film as the semiconductor channel layer and a Pb(Zr0.7Ti0.3)O3 film as the ferroelectric gate dielectric. The excellent characteristics of the transistor together with superior thermal stability and mechanical flexibility are demonstrated through various mechanical bending and temperature measurements. The on/off current ratio of the FeFET is higher than 103, which based on the field effect in the transfer curve. The smallest bending radius that can be achieved is 5 mm with a cyclability of 300 times and a retention of 100 h. This study opens an avenue to use oxide heteroepitaxy to construct a FeFET for next-generation flexible electronic systems.

Transparent Antiradiative Ferroelectric Heterostructure Based on Flexible Oxide Heteroepitaxy.

In the era of Internet of Things, the demand for flexible and transparent electronic devices has shifted to the forefront of materials science research. However, the radiation damage to key performance of transparent devices under radiative environment remains as a critical issue. Here, we present a promising technology for nonvolatile transparent electronic devices based on flexible oxide heteroepitaxy. A direct fabrication of epitaxial lead lanthanum zirconate titanate on transparent flexible mica substrate with indium tin oxide electrodes is presented. The transparent flexible ferroelectric heterostructures not only retain their superior performance, thermal stability, reliability, and mechanical durability, but also exhibit remarkably robust properties against to a strong radiation exposure. Our study demonstrates an extraordinary concept to realize transparent flexible nonvolatile electronic devices for the design and development of next-generation smart devices with potential application in electronics, automotive, aerospace, and nuclear systems.

Flexible ferroelectric element based on van der Waals heteroepitaxy.

We present a promising technology for nonvolatile flexible electronic devices: A direct fabrication of epitaxial lead zirconium titanate (PZT) on flexible mica substrate via van der Waals epitaxy. These single-crystalline flexible ferroelectric PZT films not only retain their performance, reliability, and thermal stability comparable to those on rigid counterparts in tests of nonvolatile memory elements but also exhibit remarkable mechanical properties with robust operation in bent states (bending radii down to 2.5 mm) and cycling tests (1000 times). This study marks the technological advancement toward realizing much-awaited flexible yet single-crystalline nonvolatile electronic devices for the design and development of flexible, lightweight, and next-generation smart devices with potential applications in electronics, robotics, automotive, health care, industrial, and military systems.

[Genetic diversity of Pseudosciaena polyactis in Zhoushan based on mitochondrial DNA D-loop region sequences].

Pseudosciaena polyactis is an economically important species of marine fish in China that is currently declining due to overexploitation, environmental pollution and related factors. Research in to the genetic structure of Pseudosciaena polyactis populations plays a key role in protecting and promoting sustainable utilization. We collected 53 individuals of Pseudosciaena polyactis from Zhoushan, Zhejiang and sequenced and amplified the mitochondrial DNA (mtDNA) D-loop region using Polymerase Chain Reactions (PCR). The sequence length of the 53 individuals ranged from 795 to 801 bp. The sequences were analyzed by Clustal X1.83, MEGA3.1 and DnaSP4.0. The results showed that the average base content of T, C, A, G was 30.3%, 23.1%, 32.3% and 14.3%, respectively and there were 93 transition or transversion sites, including 53 single nucleotide mutation sites and 40 parsimony informative sites, which accounted for 11.6% of the length of the analyzed sequences. In total, we identified 52 haplotypes and found haplotype diversity (hd) of 0.9993, average number of nucleotide differences were 9.73875 (k), and nucleotide diversity (Π) of 0.01233. The average genetic distance of haplotypes was 0.012, and the average transition/transversion was 4.305. Based on mitochondrial DNA D-loop region sequences, these results indicate that the genetic diversity of the Pseudosciaena polyactis population in Zhoushan is currently at a medium level.

Aicardi syndrome in a 47, XXY male neonate with lissencephaly and holoprosencephaly.

Aicardi syndrome (AS) is a rare neuro-ophthalmic disorder first described by Jean Aicardi in 1965 with a characteristic triad of corpus callosal agenesis (CCA), chorioretinal lacunae (CRL), and infantile spasms (IS). All known cases of AS have been sporadic and a responsible gene has not been identified. With 5 exceptional males, potential X-linked dominant genetic mutation characterizes AS occurring almost exclusively in girls. Most of male AS cases were still debatable in diagnosis either for their 46 XY karyotype or too atypical presentations to fit the formerly stricter diagnostic criteria. We report a 47, XXY male neonate presenting some undisputable, but otherwise some regarded as atypical features in AS. We compare his distinctively clinical pictures with previously reported male cases and find CRL is less pathognomonic and lissencephaly appears frequently among male AS. Because of insufficient genetic and biochemical markers for definite diagnosis at this moment, we suggest the experience of a relatively rare male case would help to shed light on the underlying genetic pathogenesis of AS.

[Study on HPLC fingerprint characteristic analysis of Cordyceps sinensis and its similar products].

OBJECTIVE: To study on HPLC fingerprint characteristic analysis of Cordyceps sinensis and its similar products. METHODS: To determinate 13 samples of Cordyceps sinensis and its similar products by HPLC, and analyze the HPLC results with similar appraisal method and graphical methods of multivariate sample in two dimensional plane such as the methods of profile, radar chart and constellation graph. RESULTS: The similar appraisal method might synthesize the similar degree in quantification, while the graphical methods such as profile graph, radar chart and constellation graph could show more details about the classification and the characteristic of varieties directly. CONCLUSIONS: We recommend the combined application of similar appraisal method and the graphical methods due to its advantages on the judgment and characteristic analysis of fingerprint.

Hospitalized eye injury in a large industrial city of South-Eastern Asia.

BACKGROUND: Wearing appropriate eye-protection devices in workplace, sports and motorcycling have not been a routine in most of Asian countries. The purpose of this study is to assess the frequency, causes, mechanisms, functional outcomes and costs of hospitalized eye injuries in a large industrial city in South Eastern Asia. METHODS: A retrospective review of the hospital admission files of ocular trauma admitted to the Kaohsiung Medical University Hospital from January 2001 to December 2002. RESULTS: One hundred and sixty cases of eye injuries were identified for study. Male patients (83.1%) were significantly more than female, while in the work-related group, male was predominant with 92.2%. Work-related injuries accounted for 48.1% (77 cases) with a mean age of 42.3 years, older than the 36.0 years mean for the non-work-related group. The most common cause of hospitalized injury was contusion injury (49.4%), while in the work-related group it was open-globe trauma (34.0%). Hyphema of anterior chamber (23.1%) was the most common diagnosis, followed by vitreous hemorrhage (15.6%) and corneal perforation (13.8%). In work-related injuries, lid and corneal lacerations were the most common. The visual prognosis was poor in injured eyes, with 39.6% eyes having final best corrected visual acuity less than 0.1, and it was even worse at 43.8% in work-related group. The most frequent (46.8%) durations of hospital stay were from 3 to 5 days. The mean cost of eye injuries per case in the work-related group was 1382 US dollars, significantly more than the 909 US dollars per case for the non-work-related group. CONCLUSION: The hospitalized ocular injuries incurred significant visual loss, health-care expenses and socio-economic impacts. Safety strategies aimed at preventing eye injury are mandatory.