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Tao Meng, Fenyun Yi, Honghong Cheng, Junnan Hao, Dong Shu, Shixu Zhao, Chun He, Xiaona Song, Fan Zhang
Using ammonium chloride (NH4Cl) as the pore-forming agent, three-dimensional (3D) "fishnet-like" lithium titanate/reduced graphene oxide (LTO/G) composites with hierarchical porous structure are prepared via a gas-foaming method. SEM and TEM images show that in the composite prepared with the NH4Cl concentration of 1 mg mL-1 (1-LTO/G), LTO particles with sizes of 50~100 nm disperse homogeneously on the 3D "fishnet-like" graphene sheets. The nitrogen-sorption analyses reveal the existence of micro/mesopores, which is attributed to the introduction of NH4Cl into the gap between the graphene sheets that further decomposes into gases and produces hierarchical pores during the thermal treatment process...
November 17, 2017: ACS Applied Materials & Interfaces
Elisabeth Berger, Peter Haase, Ralf B Schäfer, Andrea Sundermann
Monitoring of macroinvertebrate communities is frequently used to define the ecological health status of rivers. Ideally, biomonitoring should also give an indication on the major stressors acting on the macroinvertebrate communities supporting the selection of appropriate management measures. However, most indices are affected by more than one stressor. Biological traits (e.g. size, generation time, reproduction) could potentially lead to more stressor-specific indices. However, such an approach has rarely been tested...
November 13, 2017: Science of the Total Environment
Wei-Qiang Liao, Yuan-Yuan Tang, Peng-Fei Li, Yu-Meng You, Ren-Gen Xiong
Piezoelectric materials have been widely used in various applications, such as high-voltage sources, actuators, sensors, motors, fre-quency standard, vibration reducer, and so on. In the past decades, lead zirconate titanate (PZT) binary ferroelectric ceramics have dominated the commercial piezoelectric market due to their excellent properties near the morphotropic phase boundary (MPB), although they contain more than 60% toxic lead element. Here, we report a lead-free and one-composition molecular ferroelectric trimethylbromomethylammonium tribromomanganese (ΙΙ) (TMBM-MnBr3) with a large piezoelectric coefficient d33 of 112 pC/N along polar axis, comparable with those of typically one-composition piezoceramics such as BaTiO3 along polar axis [001] (~90 pC/N) and much greater than those of most known molecular ferroelectrics (almost below 40 pC/N)...
November 16, 2017: Journal of the American Chemical Society
Songkot Utara, Sitchai Hunpratub
Barium titanate (BaTiO3) nanoparticles were successfully synthesized via a sonochemical method (25 kHz) at a constant temperature of 25 °C and atmospheric pressure without a calcination step. Barium hydroxide Ba(OH)2 and diisopropoxytitanium bis(acetylacetonate) (C12H28O6Ti) were used as the starting materials. The effects of the concentration of NaOH used and ultrasonic reaction time were investigated. The phase composition, functional groups and morphology of synthesized powders were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Fourier transform Raman spectroscopy (FT-Raman) and transmission electron microscopy (TEM)...
March 2018: Ultrasonics Sonochemistry
A Moghtada, R Ashiri
The results indicated that the ultrasonic sonochemistry which brings into play the acoustic cavitation phenomenon is more powerful and feasible in synthesizing the mixed oxides in contrast to the conventional solid-state approaches. The obtained results demonstrated that the sonochemical approach is able to obtain highly pure powder product at a much lower processing temperature of about 323K (50°C) in contrast to 1173K (900°C) which is essential for the synthesis by the mechanochemical approach. Sonochemical synthesis benefits from homogenous ordering the reactant ions (which have been dissolved in the solution mixture) into perovskite structure using ultrasonication...
March 2018: Ultrasonics Sonochemistry
Kong-Peng Lv, Lucy Norman, Yi-Liang Li
Since Earth's biochemistry is carbon-based and water-borne, the main strategies for searching for life elsewhere are "follow the carbon" and "follow the water." Recently, however, there is a growing focus on the prospect that putative exotic life on other planets could rely on unearthly biochemistries. Here, we hypothesize a novel oxygen-free organic chemistry for supporting potential exotic biosystems, which is named CHN biochemistry. This oxygen-free CHN biochemistry starts from simple oxygen-free species (including hydrocarbons, hydrogen cyanide, and nitriles) and produces a range of functional macromolecules that may function in similar ways to terran macromolecules, such as sugars (cyanosugars), acids (cyanoacids), amino acids (amino cyanoacids), and nucleobases (cyanonucleobases)...
November 2017: Astrobiology
Alfin Kurniawan, Chintya Effendi, Meng-Jiy Wang
The incorporation of inorganic materials into electrospun nanofibers has recently gained considerable attention for the development of ECM-like scaffolds with improved mechanical properties and enhanced biological functions for tissue engineering applications. In this study, polymer-inorganic composite fibers consisting of poly(2-ethyl-2-oxazoline) (PEOXA) and tetrabutyl titanate (TBT) as the titanium precursor were successfully fabricated through a combined sol-gel/electrospinning approach. PEOXA/Ti(OR)n composite fibers were obtained with varying amounts of polymer and titanium precursors...
November 14, 2017: Journal of Tissue Engineering and Regenerative Medicine
Katlyn M Turner, Cameron L Tracy, Wendy L Mao, Rodney C Ewing
Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln=Nd, Gd, and Er) were investigated in situ to 50 GPa in order to determine their structural response to compression and compare it to that of lanthanide titanate, zirconate, and hafnate pyrochlores. The cation radius ratio of A3+/B4+ in pyrochlore oxides (A2B2O7) is thought to be the dominant property that influences their compression response. The ionic radius of Sn4+ is intermediate to that of Ti4+, Zr4+, and Hf4+, but the <Sn-O> bond in stannate pyrochlore is more covalent than the <B-O> bonds in titanates, zirconate, and hafnates...
November 9, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Ashley L Titan, Kelly Devereaux, John D Louie, George A Poultsides
No abstract text is available yet for this article.
November 8, 2017: Digestive Diseases and Sciences
Tao Wan, Bo Qu, Haiwei Du, Xi Lin, Qianru Lin, Da-Wei Wang, Claudio Cazorla, Sean Li, Sidong Liu, Dewei Chu
Resistive switching behaviour can be classified into digital and analog switching based on its abrupt and gradual resistance change characteristics. Realizing the transition from digital to analog switching in the same device is essential for understanding and controlling the performance of the devices with various switching mechanisms. Here, we investigate the resistive switching in a device made with strontium titanate (SrTiO3) nanoparticles using X-ray diffractometry, scanning electron microscopy, Raman spectroscopy, and direct electrical measurements...
October 31, 2017: Journal of Colloid and Interface Science
Wenjing Guo, Yuanrong Zhu, Zhiyou Fu, Ning Qin, Hao Wang, Shasha Liu, Yan Hu, Fengchang Wu, John P Giesy
Long-term (2000 to 2012) monthly data on communities of phytoplankton, and environmental variables were measured in water collected from Meiliang Bay and Wuli Lake of Tai Lake, China. Redundancy analysis (RDA) was conducted to explore relationships between the phytoplankton communities and environmental variables. Change points for concentrations of nutrients, which serve as early warnings of state shifts in lacustrine ecosystems, were identified using the Threshold Indicator Taxa Analysis (TITAN). The biomass of phytoplankton was positively correlated with the concentrations of total phosphorus (TP), suspended solids (SS), water temperature (WT), and pH but negatively correlated with the N/P ratio (by mass) and Secchi disk depth (SD)...
November 4, 2017: Environmental Monitoring and Assessment
Luying Li, Xiaokang Hu, Fan Jiang, Wenkui Jing, Cong Guo, Shuangfeng Jia, Yihua Gao, Jianbo Wang
The phenomenon of cation ordering is closely related to certain physical properties of complex oxides, which necessitates the search of underlying structure-property relationship at atomic resolution. Here we study the superlattices within reduced calcium titanate single crystal micro-pillars, which are unexpected from the originally proposed atomic model. Bright and dark contrasts at alternating Ti double layers perpendicular to b axis are clearly observed, but show no signs in corresponding image simulations based on the proposed atomic model...
November 3, 2017: Scientific Reports
Delhia Alby, Clarence Charnay, Marc Heran, Bénédicte Prelot, Jerzy Zajac
Liquid wastes containing non-ferrous heavy metal ions and some radionuclides, (137)Cs and (90)Sr in particular, represent one of the most dangerous sources of environmental contamination. The remediation of wastewater containing such pollutants continue to be among the biggest challenges of Sustainable Development and Environmental Safety. Sorption-based technologies have proven their efficiency also in reducing the radionuclide content in aqueous streams to low-level residual activity, with the concomitant decrease in the amount of ultimate solid waste generated...
October 24, 2017: Journal of Hazardous Materials
Frederick A Pearsall, Julien Lombardi, Stephen O'Brien
Frequency stable, high permittivity nanocomposite capacitors produced under mild processing conditions offer an attractive replacement to MLCCs derived from conventional ceramic firing. Here, 0-3 nanocomposites were prepared using gel-collection derived barium titanate nanocrystals, suspended in a poly(furfuryl alcohol) matrix, resulting in a stable, high effective permittivity, low loss dielectric. The nanocrystals are produced at 60 °C, emerging as fully crystallized cubic BTO, 8 nm, paraelectric with a highly functional surface that enables both suspension and chemical reaction in organic solvents...
November 7, 2017: ACS Applied Materials & Interfaces
Xiaofeng Cao, Jie Wang, Dalin Jiang, Jinhua Sun, Yi Huang, Shengji Luan
The establishment of numeric nutrient criteria is essential to aid the control of nutrient pollution and for protecting and restoring healthy ecological conditions. However, it's necessary to determine whether regional nutrient criteria can be defined in stream ecosystems with a poor ecological status. A database of periphytic diatom samples was collected in July and August 2011 and 2012. In total 172 samples were included in the database with matching environmental variables. Here, percentile estimates, nonparametric change-point analysis (nCPA) and Threshold Indicator Taxa ANalysis (TITAN) were conducted to detect the reference conditions and ecological thresholds along a total nitrogen (TN) and total phosphorus (TP) gradient and ammonia nitrogen (NH3-N) for the development of nutrient criteria in the streams of the Lake Dianchi basin...
November 1, 2017: Environmental Science. Processes & Impacts
H Khanbareh, S van der Zwaag, W A Groen
Composites of lead zirconate titanate particles in an epoxy matrix are prepared in the form of 0-3 and quasi 1-3 with different ceramic volume contents from 10% to 50%. Two different processing routes are tested. Firstly a conventional dielectrophoretic structuring is used to induce a chain-like particle configuration, followed by curing the matrix and poling at a high temperature and under a high voltage. Secondly a simultaneous combination of dielectrophoresis and poling is applied at room temperature while the polymer is in the liquid state followed by subsequent curing...
November 2017: Journal of Intelligent Material Systems and Structures
Linsheng Huo, Bo Wang, Dongdong Chen, Gangbing Song
Rock bolts ensure structural stability for tunnels and many other underground structures. The pre-load on a rock bolt plays an important role in the structural reinforcement and it is vital to monitor the pre-load status of rock bolts. In this paper, a rock bolt pre-load monitoring method based on the piezoceramic enabled time reversal method is proposed. A lead zirconate titanate (PZT) patch transducer, which works as an actuator to generate stress waves, is bonded onto the anchor plate of the rock bolt. A smart washer, which is fabricated by sandwiching a PZT patch between two metal rings, is installed between the hex nut and the anchor plate along the rock bolt...
October 27, 2017: Sensors
Fadoua Sallem, Julien Boudon, Olivier Heintz, Isabelle Séverin, Adel Megriche, Nadine Millot
In this work, we discuss for the first time the elaboration of nanohybrid materials, intended for drug delivery systems, based on titanate nanotubes (TiONts) coated with chitosan polymer (CT). Chitosan has been used to enhance the biocompatibility of hydrothermally synthesized nanotubes in biological medium as a substitute for the polyethylene glycol (PEG) that is generally used for biocompatibility. CT grafting was carried out using two different approaches; the first was made by a covalent bond using two intermediate molecules, and the second is based on electrostatic interactions between CT and TiONts...
November 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Yingwei Wu, Dmitry Isakov, Patrick S Grant
Additive manufacturing of complex structures with spatially varying electromagnetic properties can enable new applications in high-technology sectors such as communications and sensors. This work presents the fabrication method as well as microstructural and dielectric characterization of bespoke composite filaments for fused deposition modeling (FDM) 3D printing of microwave devices with a high relative dielectric permittivity ϵ = 11 in the GHz frequency range. The filament is composed of 32 vol % of ferroelectric barium titanate (BaTiO 3 ) micro-particles in a polymeric acrylonitrile butadiene styrene (ABS) matrix...
October 23, 2017: Materials
A Gomez, M Gich, A Carretero-Genevrier, T Puig, X Obradors
While piezoelectric and ferroelectric materials play a key role in many everyday applications, there are still a number of open questions related to their physics. To enhance our understanding of piezoelectrics and ferroelectrics, nanoscale characterization is essential. Here, we develop an atomic force microscopy based mode that obtains a direct quantitative analysis of the piezoelectric coefficient d33. We report nanoscale images of piezogenerated charge in a thick single crystal of periodically poled lithium niobate (PPLN), a bismuth ferrite (BiFO3) thin film, and lead zirconate titanate (PZT) by applying a force and recording the current produced by these materials...
October 24, 2017: Nature Communications
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