High-temperature BaTiO_(3) -based ceramic capacitors by entropy engineering design

High-performance BaTiO_(3)(BTO)-based dielectric ceramics have great potential for high-power energy storagedevices. However, its poor temperature reliability and stability due to its low Curie temperature impedes the development ofmost electronic applications. Herein, a series of BTO-based ceramics are designed and prepared on the basis of entropyengineering. Owing to the incorporation of Bi(Mg_(0.5)Ti_(0.5))O_(3), relaxation behavior and low dielectric loss at high temperatureshave been achieved. Moreover, the high-entropy strategy also promotes lattice distortion, grain refinement and excellentresistance, which together increase the breakdown field strength. These simultaneous effects result in outstanding energystorage performance, ultimately achieving stable energy density (U_(e)) of 5.76 J·cm^(−3) and efficiency ( η) of 89%. Mostimportantly, the outstanding temperature stability makes high-entropy BTO-based ceramics realize a significant energystorage density of 4.90 0.14 J·cm^(−3) with the efficiency above 89%, spanning a wide temperature range of 25–250 ℃, aswell as cycling reliability with negligible performance deterioration after 3 105 cycles at 300 kV∙cm^(−1) and 200 ℃. Thisresearch presents an effective method for designing temperature-stable and reliable dielectrics with comprehensive energystorage performance.

Effect of VC/Cr_3C_2 on microstructure and mechanical properties of Ti(C,N)-based cermets

Effects of VC/Cr3C2 on the microstructure and mechanical properties of Ti（C,N）-based cermets were studied. The microstructure was investigated by means of optical microscopy, X-ray diffractometry as well as scanning electron microscopy in combination with energy dispersive spectrometry. Mechanical properties, such as transverse rupture strength, hardness and fracture toughness, were measured. The results show that there are black core-grey rim structure and white core-grey rim structure in the microstructure. The grains become fine due to the VC/Cr3C2, and the grains of cermet added with 0.75VC/0.25Cr3C2 are refined most remarkably. The black core becomes finer with the increase of VC addition and rim phase becomes thicker with the decrease of Cr3C2 addition. The porosity increases with the increase of VC addition in VC/Cr3C2. Compared with the cermet free of VC/Cr3C2, the transverse rupture strength and hardness of cermets with VC/Cr3C2 are both improved, and the maximum values are both found for the cermet with 0.25VC/0.75Cr3C2. The fracture toughness can be effectively promoted by adding VC/Cr3C2 with an appropriate ratio of VC to Cr3C2, and the maximum value is found for the cermet with 0.5VC/0.5Cr3C2.

Research progress of Ag_3PO_4-based photocatalyst: Fundamentals and performance enhancement

Ag3PO4 is found to be a highly efficient photocatalyst and receives great attention. The high activity of the photocatalyst is credited to the intrinsic electronic structure. The morphology control and nano-composite fabrication are used to improve the performance and practicability. This paper reviews the structure, properties and some theoretical aspects of Ag3PO4 single crystal. Also, the major strategies, namely the morphology control and hetero-nanostructure construction, as ways to improve the performance of Ag3PO4-based photocatalysts, are summarized with the aid of some typical instances.

Fundamental and progress of Bi_2Te_3-based thermoelectric materials

Thermoelectric materials,enabling the directing conversion between heat and electricity,are one of the promising candidates for overcoming environmental pollution and the upcoming energy shortage caused by the over-consumption of fossil fuels.Bi2Te3-based alloys are the classical thermoelectric materials working near room temperature.Due to the intensive theoretical investigations and experimental demonstrations,significant progress has been achieved to enhance the thermoelectric performance of Bi2Te3-based thermoelectric materials.In this review,we first explored the fundamentals of thermoelectric effect and derived the equations for thermoelectric properties.On this basis,we studied the effect of material parameters on thermoelectric properties.Then,we analyzed the features of Bi2Te3-based thermoelectric materials,including the lattice defects,anisotropic behavior and the strong bipolar conduction at relatively high temperature.Then we accordingly summarized the strategies for enhancing the thermoelectric performance,including point defect engineering,texture alignment,and band gap enlargement.Moreover,we highlighted the progress in decreasing thermal conductivity using nanostructures fabricated by solution grown method,ball milling,and melt spinning.Lastly,we employed modeling analysis to uncover the principles of anisotropy behavior and the achieved enhancement in Bi2Te3,which will enlighten the enhancement of thermoelectric performance in broader materials

A RESEARCH ON THE MEDIUM TEMPERATURE SINTERED BaTiO_3-BASE CERAMIC MATERIAL FOR MLC WITH X7R BEHAVIOR

采用加入Ｂｉ２Ｏ３＿ＰｂＯ＿ＺｎＯ玻璃及Ｂｉ、Ｃｏ、Ｎｂ掺杂的方法，使ＢａＴｉＯ３基铁电瓷料中温烧结（１０８０～１１４０℃）。在实验结果的基础上，探讨Ｘ７Ｒ铁电瓷料中的第二相和晶粒尺寸对ＭＬＣ的ε＿ｔ性能的影响，并研究其烧结机制。

Bio‐inspired nanostructured g-C_(3)N_(4)-based photocatalysts:A comprehensive review

As a new organic conjugated semiconductor,graphitic carbon nitride(g-C_(3)N_(4))is emerging as a fascinating material for various photocatalytic applications due to its adjustable electronic structure,outstanding thermal endurance,appealing chemical stability,low cost,and environmental friendliness.Nevertheless,unmodified bulk g-C_(3)N_(4) possesses some intrinsic limitations related to poor crystallinity,marginal visible-light harvesting,easy recombination of charge pairs,small surface area,and slow charge migration,which give rise to the low quantum efficiency of photocatalytic reactions.One efficient strategy to overcome these shortcomings is the manipulation of the microstructures of g-C_(3)N_(4).Other than the traditional structure control,mimicking the structures of creatures in nature to design and construct bio-inspired structures is a promising approach to improve the photocatalytic performance of g-C_(3)N_(4) and even g-C_(3)N_(4)-based systems.This review summarizes the recent advances of the traditional structure-control of g-C_(3)N_(4)-based systems,and bio-inspired synthesis of g-C_(3)N_(4)-based systems from two aspects of structural bionics and functional bionics.Furthermore,the fundamentals of bio-inspired design and fabrication of g-C_(3)N_(4)-based systems are introduced in detail.Additionally,the different theoretical calculations,diverse photocatalytic applications and various modification strategies of bio-inspired structured g-C_(3)N_(4)-based systems are recapped.We believe that this work will be a guiding star for future research in the new field of biomimetic photocatalysis.

Synergistically Toughening Effect of SiC Whiskers and Nanoparticles in Al_2O_3-based Composite Ceramic Cutting Tool Material

In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiC np advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vo1% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730＋ 95 MPa and fracture toughness is 5.6 ± 0.6 MPa.m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.

New technique of comprehensive utilization of spent Al_2O_3-based catalyst

A new technology was developed to recover multiple valuable elements from the spent Al2O3-based catalyst by X-ray phase analysis and exploratory experiments. The experimental results show that in the condition of roasting temperature of 750℃ and roasting time of 30 min, molar ratio of Na2O to Al2O3 of 1.2, the leaching rates of alumina, vanadium and molybdenum in the spent catalyst are 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by precipitators A and B, and the precipitation rates of vanadium and molybdenum are 94.8% and 92.6%. Al（OH）3 was prepared from sodium aluminate solution in the carbonation decomposition process, and the purity of Al2O3 is 99.9% after calcination, the recovery of alumina reaches 90.6% in the whole process; the Ni-Co concentrate was leached by sulfuric acid, a nickel recovery of 98.2% and cobalt recovery over 98.5% can be obtained under the experimental condition of 30% H2SO4, 80℃, reaction time 4 h, mass ratio of liquid to solid 8, stirring rate 800r/min.

DPGL:The Direct3D9-based Parallel Graphics Library for Multi-display Environment

The emergence of high performance 3D graphics cards has opened the way to PC clusters for high performance multi- display environment. In order to exploit the rendering ability of PC clusters, we should design appropriate parallel rendering algorithms and parallel graphics library interfaces. Due to the rapid development of Direct3D, we bring forward DPGL, the Direct3D9-based parallel graphics library in D3DPR parallel rendering system, which implements Direct3D9 interfaces to support existing Direct3D9 application parallelization with no modification. Based on the parallelism analysis of Direct3D9 rendering pipeline, we briefly introduce D3DPR parallel rendering system. DPGL is the fundamental component of D3DPR. After presenting DPGL three layers architecture, we discuss the rendering resource interception and management. Finally, we describe the design and implementation of DPGL in detail, including rendering command interception layer, rendering command interpretation layer and rendering resource parallelization layer.

Effects of Thickness and Temperature on Thermoelectric Properties of Bi2Te3-Based Thin Films

Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices of different thicknesses are prepared on the silicon dioxide substrates by magnetron sputtering technique and thermally annealed at 573 K for 30 min. Thermoelectric（TE）measurements indicate that optimal thickness and thickness ratio improve the TE performance of Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices, respectively. High TE performances with figure-of-merit（ZT） values as high as 1.32 and 1.56 are achieved at 443 K for 30 nm and 50 nm Bi_2Te_3 thin films, respectively. These ZT values are higher than those of p-type Bi_2Te_3 alloys as reported. Relatively high ZT of the GeTe/B_2Te_3 superlattices at 300-380 K were 0.62-0.76. The achieved high ZT value may be attributed to the unique nano-and microstructures of the films,which increase phonon scattering and reduce thermal conductivity. The results indicate that Bi_2Te_3-based thin films can serve as high-performance materials for applications in TE devices.

Total Ionization Dose Effects on Charge Storage Capability of Al2O3/HfO2/Al2O3-Based Charge Trapping Memory Cell

Because of the discrete charge storage mechanism, charge trapping memory（CTM） technique is a good candidate for aerospace and military missions. The total ionization dose（TID） effects on CTM cells with Al2O3/HfO2/Al2O3（AHA） high-k gate stack structure under in-situ 10 keV x-rays are studied. The C-V characteristics at different radiation doses demonstrate that charge stored in the device continues to be leaked away during the irradiation,thereby inducing the shift of flat band voltage（V（fb））. The dc memory window shows insignificant changes, suggesting the existence of good P/E ability. Furthermore, the physical mechanisms of TID induced radiation damages in AHA-based CTM are analyzed.

Single-and Two-band Transport Properties Crossover in Bi_(2)Te_(3)Based Thermoelectrics

Based on Peltier effect,Bi_(2)Te_(3)-based alloy is widely used in commercial solid-state refrigeration at room temperature.The mainstream strategies for enhancing room-temperature thermoelectric performance in Bi_(2)Te_(3)focus on band and microstructure engineering.However,a clear understanding of the modulation of band structure and scattering through such engineering remains still challenging,because the minority carriers compensate partially the overall transport properties for the narrow-gap Bi_(2)Te_(3)at room temperature(known as the bipolar effect).The purpose of this work is to model the transport properties near and far away from the bipolar effect region for Bi_(2)Te_(3)-based thermoelectric material by a two-band model taking contributions of both majority and minority carriers into account.This is endowed by shifting the Fermi level from the conduction band to the valence band during the modeling.A large amount of data of Bi_(2)Te_(3)-based materials is collected from various studies for the comparison between experimental and predicted properties.The fundamental parameters,such as the density of states effective masses and deformation potential coefficients,of Bi_(2)Te_(3)-based materials are quantified.The analysis can help find out the impact factors(e.g.the mobility ratio between conduction and valence bands)for the improvement of thermoelectric properties for Bi_(2)Te_(3)-based alloys.This work provides a convenient tool for analyzing and predicting the transport performance even in the presence of bipolar effect,which can facilitate the development of the narrow-gap thermoelectric semiconductors.

Photocatalytic Degradation of Oxytetracycline Dihydrate from Aqueous Solution Using Nano ZnO and ZnO.xBaTiO3 (x = 3%, 18%, 33% and 48%)

Traditional wastewater mostly contains pharmaceutical ingredients. Therefore, the wastewater must be completely free from antibiotics before its release into the environment. In the present study, photocatalytic degradation was done to investigate the removal efficiency of Oxytetracycline Dihydrate (OTC) using ZnO, ZnO/3%BaTiO3 (3 BZ), ZnO/18%BaTiO3 (18 BZ), ZnO/ 33%BaTiO3 (33 BZ) and ZnO/48%BaTiO3 (48 BZ) under UV light. After the exposure time of 420 min, about 99.57% and 97.87% of OTC was degraded using ZnO and 3 BZ respectively. Further, increasing the amount of BaTiO3 in ZnO prolongs the degradation time. Therefore, faster efficiency was found using ZnO nanoparticles. The observed reaction rate constant using ZnO was 0.00933 min-1 which decreased to 0.00532 min-1 using 48 BZ, indicating the decrease of reaction rate for increasing the amount of BaTiO3. Hence, the use of ZnO photocatalyst is anticipated to be a promising technique for the photocatalytic degradation of contaminated wastewater with oxytetracycline antibiotics using UV light.

Study of Bi_2O_3-based Rare Earth Solid Electrolyte Used in Fuel Cell

Solid ceramic electrolyte materials (Bi_2O_3)_(0.75)(Y_2O_3)_(0.25) and(Bi_2O_3)_(0.65)(Gd_2O_3 )_(0.35)were synthesized.Their crystal structure, XPS spectra and the change of ionic conductivity versus temperature were measured.A Bi_2O_3-based rare earth solid electrolyte fuel cell with ZrO_2-Y_2O_3 protection film was made.

Removal of Basic and Non-Basic Nitrogen Compounds from Model Oil by FeCl_(3)-Based Ionic Liquids

The low-viscosity FeCl_(3)-based ionic liquids(ILs)prepared from the interaction of anhydrous FeCl_(3) and alkyl imidazolium bromide([1-alkyl-3-methyl-imidazolium]Br,alkyl=ethyl,butyl,hexyl,octyl)are highly effective for the denitrogenation of model oil containing quinoline or indole.The results indicate that the chain length of the alkyl group on the imidazolium cation has little influence on the N-extraction efficiency.With the selected IL[Bmim]Br/FeCl_(3),up to 99.1%of N-extraction efficiency from model oil containing quinoline can be attained at an extraction temperature of 30°C with an IL/oil mass ratio of 1/7 and an extraction time of 30 min.The indole extraction efficiency reaches 98.9%at an IL/oil mass ratio of 1:1.Moreover,the quinoline extraction efficiency remains as high as 92.3%after the IL has been recycled four times.

New flexible CsPbBr_(3)-based scintillator for X-ray tomography

The evolution of lead halide perovskites used for X-ray imaging scintillators has been facilitated by the development of solution-processable semiconductors characterized by large-area,flexible,fast photoresponse.The stability and durability of these new perovskites are insufficient to achieve extended computed tomography scanning times with hard X-rays.In this study,we fabricated a self-assembled CsPbBr_(3)-based scintillator film with a flexible large-area uniform thickness using a new roomtemperature solution-processable method.The sensitivity and responsivity of X-ray photon conversion were quantitatively measured and showed a good linear response relationship suitable for X-ray imaging.We also demonstrated,for the first time,that the self-assembled CsPbBr_(3)-based scintillator has good stability for hard X-ray microtomography.Therefore,such an inexpensive solution-processed semiconductor easily prepared at room temperature can be used as a hard X-ray scintillator and equipped with flexible CsPbBr3-based X-ray detectors.It has great potential in three-dimensional high-resolution phase-contrast X-ray-imaging applications in biomedicine and material science because of its heavy Pb and Br atoms.

STUDY ON THE INFRARED TRANSMITTING As_2Te_3-BASED CHALCOHALIDE GLASSES

This paper reports the formation and some properties of a new class of chalcohalide glasses in the As2Tef iodide systems. The As2Te3-Pb12, As2Te3-HgI2, As2Te3-CitI and As2Te3-AgI systems can form stable bulk glasses in wide composition regions ?and no bulk glass formation was found in the As2Te3-TH sys-tem. As2Te3-based glasses have glass transition tempera-

Thermoelectric Transport by Surface States in Bi2Se3-Based Topological Insulator Thin Films

We develop a tractable theoretical model to investigate the thermoelectric （TE） transport properties of surface states in topological insulator thin films （TITFs） of Bi2Sea at room temperature. The hybridization between top and bottom surface states in the TITF plays a significant role. With the increasing hybridization-induced surface gap, the electrical conductivity and electron thermal conductivity decrease while the Seebeck coefficient increases. This is due to the metal-semiconductor transition induced by the surface-state hybridization. Based on these TE transport coefficients, the TE figure-of-merit ZT is evaluated. It is shown that ZT can be greatly improved by the surface-state hybridization. Our theoretical results are pertinent to the exploration of the TE transport properties of surface states in TITFs and to the potential application of Bi2Sea-based TITFs as high-performance TE materials and devices.

Synthesis, Electrochemistry, and Fluorescence of Two Ru(phen)_3^(2+)-based Surfactants

Two new Ru(phen) -based surfactants. Ru(phen)2(phenNHCO-C(11))(PF6)2 and Ru(phen)2(phenNHCO-C(17))(PF6)2. have been designed and synthesized, whose chemical structures were characterized by means of IR. 1H NMR and MS. Also. electrochemistry and fluorescence of them are reperted.

PVDF/改性BaTiO_3复合材料介电性能研究

用硅烷和钛酸酯偶联剂对 Ba Ti O3粉进行了表面处理 ,使用溶剂法制备了 PVDF/Ba Ti O3复合薄膜。通过疏水亲油实验定性地分析了硅烷和钛酸酯偶联剂对 Ba Ti O3粉的偶联作用可以改善 PVDF/Ba-Ti O3的界面结合 ,通过测定 PVDF/Ba Ti O3的介电常数和介电损耗角正切值表征了复合材料的介电性能 ,PVDF/Ba Ti O3扫描电子显微镜 (SEM)的微观形态分析发现 ,经过偶联剂表面处理 ,Ba Ti O3粉在PVDF中的分散情况改善 。