Nitride Research Articles

INVESTIGATION OF THERMAL CONDUCTIVITY OF SILVER NANOPARTICLES IN BASEFULID OF WATER ETHYLENE GLYCOL

Nanotechnology is interface technologies that span many different science and applications area. When engineering, science and technology are conducted at the nanoscale is called as nanotechnology. It is about 1 to 100 nm (nano-meter) where nano denotes the scale range of one billionth of meter. Nanotechnology refers the properties of atoms and molecules measuring 0.1 to 1000 nm. Nanofluids are nothing but suspension of nanometer sized particles in the base of fluid. The base fluid can be water based or non water based depending on the application. Common nano particles are oxides, carbides, metals, carbon nano particles or nitrides. These fluids act as Newtonian fluids but in some cases these fluids do not work accurately hence non-Newtonian fluids are considered. Recent investigations on nanofluids, suggest that the suspended nanoparticles alter the transport properties and heat transfer characteristics of the suspension. This research summarizes recent trends on nanofluid heat transfer characteristics of Ag/H2O-EG nanofluids in free convection flows and identifies opportunities for future research.

Computer modeling to forecast accurate of efficiency parameters of different size of graphene platelet, carbon, and boron nitride nanotubes: A molecular dynamics simulation

In the present work, an extensive study for predicting efficiency parameters (ji) of various simulated nanocomposites including Polymethyl methacrylate (PMMA) as matrix and different structures including various sizes of graphene platelets (GPLs), single, double, and multi-walled carbon nanotubes (SWCNTs-DWCNTs-MWCNTs), and single and double-walled boron nitride nanotubes (SWBNNTs-DWBNNTs) are investigated. It should be stated that GPLs, carbon and boron nitride nanotubes (CNTs, BNNT) with different chiralities (5, 0), (5, 5), (10, 0), and (10, 10) as reinforcements are considered. In this research, molecular dynamics (MDs) method with Materials studio software is applied to examine the mechanical properties (Young's modulus) of simulated nanocomposite boxes and calculate i of each nanocomposite boxes. Then, it is noteworthy that by changing length (6.252, 10.584, and 21.173 nm) and width (7.137, 10.515, and 19.936) of GPLs, j1, j2, and j3 approximately becomes (0.101, 0.114, and 0.124), (1.15, 1.22, and 1.26), (1.04, 1.05, and 1.07) respectively. After that efficiency parameters of SWCNTs, DWCNTs, and MWCNTs are calculated and discussed separately. Finally efficiency parameters of SWBNNTs and DWBNNTs with different chiralities by PMMA as matrix are determined by MD and discussed separately. It is known that the accurate efficiency parameters helps a lot to calculate the properties of nanocomposite analytically. In particular, the obtained results from this research can be used for analytical work based on the extended rule of mixture (ERM) in bending, buckling and vibration analysis of structure in future study.

Effect of Rare Earth Addition on Microstructure, Mechanical Property and Nitriding Performance of a Medium Carbon Steel

Effect of Rare Earth Addition on Microstructure, Mechanical Property and Nitriding Performance of a Medium Carbon Steel

The Effect of Substrate Temperature on Tribological and Electrical Properties of Sputtered Carbon Nitride Thin Film

The Effect of Substrate Temperature on Tribological and Electrical Properties of Sputtered Carbon Nitride Thin Film

Nitride-Coated and Anodic-Oxidized Titanium Promote a Higher Fibroblast and Reduced Streptococcus gordonii Proliferation Compared to the Uncoated Titanium

Titanium shows optimal biocompatibility properties; however, its gray color may be a limit for aesthetic results of dental rehabilitations. Some surface treatments that change the color of the material have been proposed. The aim of this study is to, in vitro, investigate the biocompatibility of the surfaces subjected to titanium nitride (NiT) coating and anodic-oxidized (AO) treatment and their propensity to impair bacterial proliferation. The viability of primary human gingival fibroblasts (HGFs) has been evaluated through a methyl thiazolyl tetrazolium (MTT) assay in three experimental groups: uncoated titanium (UNCOATED), titanium nitride (NiT)-coated surface, and anodic-oxidized (AO) titanium. Bacterial proliferation experiments were performed using a Streptococcus gordonii clinical isolate in contact with the three different above-mentioned materials. The treated surfaces (NiT and AO) showed a significantly higher fibroblast proliferation than the uncoated titanium alloy (p < 0.05). In contrast, Streptococcus gordonii growth was significantly higher on the untreated titanium (p < 0.05).

New technique for deposition and thermochemical treatment of small parts with complex geometry applied to machining inserts

Cutting tools, such as machining inserts, which in addition to having a complex geometry need to handle different demands on more than one face during their application, stimulate investigation for new coating techniques. Even though many hard film deposition techniques are well accepted or even established among researchers and industries, these processes still need to meet a limitation that requires the repositioning of the sample for new treatments in order to cover all of its surfaces. This paper proposes a new methodology for coating deposition on complex geometry pieces, through a structure for three-dimensional plasma treatment, using a Rotary Cathodic Cage Plasma Nitriding (RCCPN). TiN films were deposited on cemented carbide inserts applied in machining processes using the RCCPN technique. The plasma parameters were kept constant and deposition time was the only variable input. The deposited films were characterized by SEM, EDS, XRD, and Vickers microhardness. It was observed that the RCCPN technique was useful in producing a uniform TiN layer in all insert surfaces, with a thickness proportional to deposition time.

Determination of isoniazid by a copper-based metal-organic frameworks/carbon nitride quantum dots modified pencil graphite electrode as a highly sensitive and selective sensor

Abstract In this work, a particular electrochemical sensor for analysis of isoniazid (INZ), a tuberculostatic drug, was presented. The electrotreated pencil graphite electrode (ETPGE) was modified by a nanocomposite of the copper-based metal-organic frameworks (Cu-MOFs)/carbon nitride quantum dots (CNQDs), Cu-MOFs/CNQDs/ETPGE, and was utilized for electroanalysis of INZ. Physicochemical characteristics and analytical performance of the Cu-MOFs/CNQDs/ETPGE were investigated through relevant instruments. Compared with bare PGE, ETPGE, CNQDs/ETPGE, and Cu-MOFs/ETPGE, the Cu-MOFs/CNQDs/ETPGE showed strong electrocatalytic activity for oxidation of the INZ and exhibited a well-defined anodic peak at a low potential of +0.364 V versus Ag/AgCl in pH 7.0 medium due to its high specific surface area, high conductivity and fast charge transfer ability. The experimental results demonstrated that the Cu-MOFs/CNQDs/ETPGE has a promising potential candidate as a stable and efficient electrochemical sensor for determination of INZ. Under the optimized experimental conditions, the designed sensor presented a wide linear response range for INZ concentration (0.1 μM to 65.0 μM) with a low practical detection limit (0.0675 μM), limit of quantification (LOQ) (0.225 μM), high sensitivity (1.507 A mol−1 L cm−2) and excellent repeatability in differential pulse voltammetry. Further, the suggested method was employed successfully for determination of INZ in drug and biological samples with satisfactory recovery values.

Novel superhard boron-rich nitrides under pressure

富硼化合物通常为潜在的超硬材料, 尽管之前的研究提出了不同晶型的BN超硬材料, 但尚未发现超硬的富硼氮化物. 本文采用基于粒子群优化算法的结构预测方法, 结合第一性原理计算, 对富硼氮化物在压力下的稳定成分及结构进行系统研究. 结果表明, 在B4N、B6N和B8N中, 硼原子都能够形成B12二十面体. 在 0–20 GPa 压力范围内, B6N是热力学稳定的, 而B4N和B8N是亚稳的. 电子性质计算表明, 预测的 Cmca B6N和 Immm B6N为半导体, 其他均为金属. 声子和弹性常数计算表明, 所有预测结构都具有动力学稳定性和机械稳定性. 值得关注的是, B4N和B6N的维氏硬度分别为45和 42 GPa, 表明其为潜在的超硬材料. 此研究丰富了B-N体系相图, 并为实验上探索超硬材料提供了丰富的理论指导.

Improved refractive-index sensing performance in medium contrast gratings by asymmetry engineering

Silicon nitride (Si3N4) subwavelength medium contrast gratings (MCGs) directly integrated with CMOS photodetectors are a promising option for on-chip label-free biosensing. The narrow spectral features required for sensing are often realized in Si3N4 nanostructures by weakly corrugated gratings which limit design flexibility. We numerically investigate the optical properties of asymmetry-engineered MCG gratings and predict the formation of ultra-sharp spectral features via the excitation of quasi-bound states in continuum (QBIC) resonances. Systematic investigation of the design parameter space shows that sharp spectral features are obtained for a wide range of parameters without requiring ultrathin grating profiles. Transmission-mode refractive index sensing simulations for bulk and surface sensing, considering both wavelength-shift and intensity-shift modalities, indicate performance gains using these structures.

Морфология и химический состав поверхности титанового сплава на начальном этапе шлифования кругом из кубического нитрида бора

Морфология и химический состав поверхности титанового сплава на начальном этапе шлифования кругом из кубического нитрида бора

Acceleration of Subwavelength Polaritons by Engineering Dielectric-Metallic Substrates

By synchrotron infrared nanospectroscopy, we demonstrate modulation of momentum and group velocity of subdiffractional hyperbolic phonon-polaritons (HP2), in hexagonal boron nitride nanocrystals, b...

Effect of Targets on Synthesis of Aluminum Nitride Thin Films Deposited by Pulsed Laser Deposition

Effect of Targets on Synthesis of Aluminum Nitride Thin Films Deposited by Pulsed Laser Deposition

A comprehensive review on the modeling of smart piezoelectric nanostructures

In this paper, a comprehensive review of nanostructures that exhibit piezoelectric behavior on all mechanical, buckling, vibrational, thermal and electrical properties is presented. It is firstly explained vast application of materials with their piezoelectric property and also introduction of other properties. Initially, more application of material which have piezoelectric property is introduced. Zinc oxide (ZnO), boron nitride (BN) and gallium nitride (GaN) respectively, are more application of piezoelectric materials. The nonlocal elasticity theory and piezoelectric constitutive relations are demonstrated to evaluate problems and analyses. Three different approaches consisting of atomistic modeling, continuum modeling and nano-scale continuum modeling in the investigation atomistic simulation of piezoelectric nanostructures are explained. Focusing on piezoelectric behavior, investigation of analyses is performed on fields of surface and small scale effects, buckling, vibration and wave propagation. Different investigations are available in literature focusing on the synthesis, applications and mechanical behaviors of piezoelectric nanostructures. In the study of vibration behavior, researches are studied on fields of linear and nonlinear, longitudinal and transverse, free and forced vibrations. This paper is intended to provide an introduction of the development of the piezoelectric nanostructures. The key issue is a very good understanding of mechanical and electrical behaviors and characteristics of piezoelectric structures to employ in electromechanical systems.

Bending and buckling analysis of sandwich Reddy beam considering shape memory alloy wires and porosity resting on Vlasov's foundation

The aim of this research is to analyze buckling and bending behavior of a sandwich Reddy beam with porous core and composite face sheets reinforced by boron nitride nanotubes (BNNTs) and shape memory alloy (SMA) wires resting on Vlasov\'s foundation. To this end, first, displacement field\'s equations are written based on the higher-order shear deformation theory (HSDT). And also, to model the SMA wire properties, constitutive equation of Brinson is used. Then, by utilizing the principle of minimum potential energy, the governing equations are derived and also, Navier\'s analytical solution is applied to solve the governing equations of the sandwich beam. The effect of some important parameters such as SMA temperature, the volume fraction of SMA, the coefficient of porosity, different patterns of BNNTs and porous distributions on the behavior of buckling and bending of the sandwich beam are investigated. The obtained results show that when SMA wires are in martensite phase, the maximum deflection of the sandwich beam decreases and the critical buckling load increases significantly. Furthermore, the porosity coefficient plays an important role in the maximum deflection and the critical buckling load. It is concluded that increasing porosity coefficient, regardless of porous distribution, leads to an increase in the critical buckling load and a decrease in the maximum deflection of the sandwich beam.

Preparation and Enhanced Visible-Light Photocatalytic Activity of Bismuth Tungstate/Graphitic Carbon Nitride Composite Modified by Bi2WO6 Quantum Dots and Nanosheets

Preparation and Enhanced Visible-Light Photocatalytic Activity of Bismuth Tungstate/Graphitic Carbon Nitride Composite Modified by Bi2WO6 Quantum Dots and Nanosheets

Modelling Temperature Dependency of Silicon Nitride Formation Kinetic during Reaction Bonded Method

Modelling Temperature Dependency of Silicon Nitride Formation Kinetic during Reaction Bonded Method

Synthesis of Boron-Aluminum Nitride Thin Film by Chemical Vapour Deposition Using Gas Bubbler

Synthesis of Boron-Aluminum Nitride Thin Film by Chemical Vapour Deposition Using Gas Bubbler

Study on the Removal of Water Pollutants by Graphite Phase Carbon Nitride Materials

Study on the Removal of Water Pollutants by Graphite Phase Carbon Nitride Materials

Niobium Nitride Catalyst for Electrocatalytic Reduction of CO 2

Converting CO2 to CO by electrochemical method is considered as an economic and friendly strategy to solve problems of resource and environment. In this work, precursor of niobium/carbon was prepared by wet chemical method and converted into Nb4N5/C and Nb2O5/C after calcination under NH3 and Ar respectively. When the nitriding temperature reaches to 700℃, prepared Nb4N5/C exhibits excellent catalytic activity with CO Faradaic efficiency of 57% at -0.83 V vs RHE in CO2 saturated 0.5 mol·L-1 NaCl solution. The results show that the catalytic activity of Nb4N5/C is related to the N doping in Nb4N5.

Research Progress in Preparation and Photocatalysis of Two-Dimensional Graphitic Carbon Nitride Nanosheets

Research Progress in Preparation and Photocatalysis of Two-Dimensional Graphitic Carbon Nitride Nanosheets