The Characteristics of Semi-Cokes --The Solid Residues from Coal Partial Gasification

In this paper the proximate analysis and ultimate analysis of sulfur in different semi-cokes generated from Rizhao bituminous coal and Beijing anthracite under different temperatures is done. Also the tendency of the contents of volatile, ash, fixed carbon and sulfur in different semi-cokes along with the different preparation temperatures is studied. Then the combustion experiment of semi-cokes in the drop-tube furnace system was carried out, and the kinetic parameters of different semi-cokes ware calculated.

Reactive reinforcement of the interface of high performance polymer blends by PMR-POI

The effect of PMR-polyimide(POI) as the interfacial agent on the interface characteristics, morphology features and crystallization of poly (ether sulfone) /poly (phenylene sulfide) (PES/PPS) and poly(ether ether ketone)/poly (ether sulfone) (PEEK/PES) partly miscible blends were investigated by means of the scanning electron microscopy, WAXD and XPS surface analysis. It is found that the interfacial adhesion was enhanced remarkably, the size of the dispersed phase particles was reduced significantly and the miscibility was improved by the addition of POI. During melt blending cross-link and/or grafting reaction of POI with PES, PEEK and PPS homopolymers was detected, however the reaction activity of POI with PPS was much higher than that of PES and PEEK. It was also found that POI was an effective nucleation agent of the crystallization of PPS.

圆柱受限空间内喷雾燃烧振荡特性研究=Investigation of the Characteristics of Thermal Instability in A Confined Combustor

本文研究了圆柱受限空间内的喷雾火焰嫩烧压力振荡的特性。为了更清楚地了解火焰的构造, 首先测量了火焰的温度场，在较大的一次风和二次风变化范围内, 测量了压力的振荡特性。结果表明，火焰的稳定是由回流区完成的, 在较小的一次风燃料当量比和中等的二次风量时, 振荡最强, 达到100Pa左右的量级,其频率为200-230Hz左右,分析表明燃烧室中的振荡是轴向驻波振荡。

Modeling Study on the Characteristics of Laminar and Turbulent Argon Plasma Jets Impinging Normally upon a Flat Plate in Ambient Air

Modeling study is performed to compare the flow and heat transfer characteristics of laminar and turbulent argon thermal-plasma jets impinging normally upon a flat plate in ambient air. The combined-diffusion-coefficient method and the turbulence-enhanced combined-diffusion-coefficient method are employed to treat the diffusion of argon in the argon-air mixture for the laminar and the turbulent cases, respectively. Modeling results presented include the flow, temperature and argon concentration fields, the air mass flow-rates entrained into the impinging plasma jets, and the distributions of the heat flux density on the plate surface. It is found that the formation of a radial wall jet on the plate surface appreciably enhances the mass flow rate of the ambient air entrained into the laminar or turbulent plasma impinging-jet. When the plate standoff distance is comparatively small, there exists a significant difference between the laminar and turbulent plasma impinging-jets in their flow fields due to the occurrence of a large closed recirculation vortex in the turbulent plasma impinging-jet, and no appreciable difference is found between the two types of jets in their maximum values and distributions of the heat flux density at the plate surface. At larger plate standoff distances, the effect of the plate on the jet flow fields only appears in the region near the plate, and the axial decaying-rates of the plasma temperature, axial velocity and argon mass fraction along the axis of the laminar plasma impinging-jet become appreciably less than their turbulent counterparts.

Influence of the Processing Conditions on the Characteristics of the Clad Layers Produced with Laminar Plasma Technology

Laminar plasma technology was used to produce ceramic hardened layers of Al2O3-40% mass Ni composite powders on stainless steel substrates. In order to investigate the influences of processing conditions on the morphologies of the surface modified layers, two different powder-feeding methods were tested, one with carrier gas called the powder injection method, and the other without carrier gas called powder transfers method. The microscopic investigations demonstrate that the cross-section of the clad layers consists of two distinct microstructural regions, in which the Al2O3 phases exhibit different growth mechanisms. When the powder transfers method is adopted, the number density and volume fraction of the Al2O3 particles increase considerably and their distributions exhibit zonal periodical characteristics. When the powder-feeding rate increases, the microstructure of the Al2O3 phases changes from a small globular to a long needle shape. Finite element simulations show that the transient thermo-physical features of the pool substances, such as solidification rate and cooling rate, influence strongly the mechanisms of the nucleation and the directional growth of the Al2O3 phases in the thermal processing.

Effects of Natural Convection on the Characteristics of a Long Laminar Argon Plasma Jet Issuing Horizontally into Ambient Air

Three-dimensional modeling results show that the appearance of the long laminar plasma jet is less influenced by natural convection even as it is issuing into ambient air horizontally. However, plasma parameter distributions may deviate from axi-symmetry

Research on the influence of fabrication parameters on the performance of buried ion-exchanged glass waveguides using the variational method

The variational method is proposed to analyze the influence of the fabrication parameters on the performance of buried K+-Na+ ion-exchanged Er3+-Yb3+ ions co-doped glass waveguide. The unknown parameters of the Hermite-Gaussian functions as the trial field distribution are determined based on the scalar variational principle. It is demonstrated that the results calculated in this paper agree with those measured in the experiment. The mode dimensions, the effective refractive index, and the overlap factor as the functions of the fabrication parameters are investigated. These results of the variational analysis are useful for the design and optimization of Er3+-Yb3+ ions co-doped waveguides.

Influence of implantation energy on the characteristics of Mn-implanted nonpolar a-plane GaN films

Nonpolar GaN Mn films have been fabricated by implanting Mn-ion into nonpolar a-plane (MO) GaN films at room temperature. The influence of implantation energy on the Structural, morphological and magnetic characteristics of samples have been investigated by means of stopping and range of ions in matter (SRIM) Simulation software, high-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and superconducting quantum interference device (SQUID). According to the SQUID analysis, obvious room temperature ferromagnetic properties of samples were detected. Moreover, the implantation energy has little impact on the ferromagnetic properties of samples. The XRD and AFM analyses show that the structural and morphological characteristics of samples were severely deteriorated with the increase of implantation energy. (C) 2008 Elsevier B.V. All rights reserved.

The impact of implantation dose on the characteristics of diluted-magnetic nonpolar GaN:Cu films

Diluted-magnetic nonpolar GaN:Cu films have been fabricated by implanting Cu ions into p-type nonpolar a-plane (1120) GaN films with a subsequent thermal annealing process. The impact of the implantation dose on the structural. morphological and magnetic characteristics of the samples have been investigated by means of high-resolution X-ray diffraction (HRXRD). atomic force microscopy (AFM), and superconducting quantum interference device (SQUID). The XRD and AFM analyses show that the structural and morphological characteristics of samples deteriorated with the increase of implantation dose. According to the SQUID analysis. obvious room-temperature ferromagnetic properties of samples were detected. Moreover, the saturation magnetization per Cu atom decreased as the implantation dose increased. (C) 2009 Elsevier B.V. All rights reserved.

Effects of techniques of implanting nitrogen into buried oxide on the characteristics of partially depleted SOIPMOSFET

Effects of techniques of implanting nitrogen into buried oxide on the characteristics of the partially depleted silicon-on-insulator (SOI) p-channel metal-oxide-semiconductor field-effect transistors (PMOSFETs) have been studied with three different nitrogen implantation doses, 8 x 10(15), 2 x 10(16), and 1 x 10(17) cm(-2). The experimental results show that this technology can affect the threshold voltage, channel hole mobility and output characteristics of the partially depleted SOI PMOSFETs fabricated with the given material and process. For each type of the partially depleted SOI PMOSFET with nitrided buried oxide, the absolute value of the average threshold voltage increases due to the nitrogen implantation. At the same time, the average channel hole mobility decreases because of the nitrogen implantation. In particular, with the high nitrogen implantation doses, the output characteristic curves of the tested transistors present a distinct kink effect, which normally exists in the characteristic output curves of only partially depleted SOI NMOSFETs.

Effects of the technology of implanting nitrogen into buried oxide layer on the characteristics of partially depleted SOI nMOSFET

The effects, caused by the process of the implantation of nitrogen in the buried oxide layer of SIMOX wafer, on the characteristics of partially depleted silicon-on-insulator nMOSFET have been studied. The experimental results show that the channel electron mobilities of the devices fabricated on the SIMON (separation by implanted oxygen and nitrogen) wafers are lower than those of the devices made on the SIMOX (separation by implanted oxygen) wafers. The devices corresponding to the lowest implantation dose have the lowest mobility within the range of the implantation dose given in this paper. The value of the channel electron mobility rises slightly and tends to a limit when the implantation dose becomes greater. This is explained in terms of the rough Si/SiO2 interface due to the process of implantation of nitrogen. The increasing negative shifts of the threshold voltages for the devices fabricated on the SIMON wafers are also observed with the increase of implanting dose of nitrogen. However, for the devices fabricated on the SIMON wafers with the lowest dose of implanted nitrogen in this paper, their threshold voltages are slightly larger on the average than those prepared on the SIMOX wafers. The shifts are considered to be due to the increment of the fixed oxide charge in SiO2 layer and the change of the density of the interface-trapped charge with the value and distribution included. In particular, the devices fabricated on the SIMON wafers show a weakened kink effect, compared to the ones made on the SIMOX wafers.