Research on pressure fluctuation of coolant with new type of boundary impedance at opening ports of water chamber

2010 ◽

Author(s):

Wei-gang Lu ◽

Ling Zhou ◽

De-sheng Zhang ◽

Ping-ping Zou ◽

Chuan Wang

Keyword(s):

Unsteady Flow ◽

Pressure Fluctuation ◽

Guide Vane ◽

Maximum Amplitude ◽

Impeller Blade ◽

Blade Passage ◽

Deep Well ◽

Unsteady Simulation ◽

New Type ◽

Steady Simulation

The interaction between impeller and guide vane of the deep well pump is one of the most important factors which cause the pressure fluctuation in the channels. However, even nowadays some flow events in the deep well pump are still under study and far from fully understood. So the unsteady flow field of a two-stage deep well pump was simulated with FLUENT code based on sliding mesh and the RNG k-ε turbulence model, to investigate the pressure fluctuation by interactions between the impeller and guide vane. The computing domain extends from the inlet of the first stage deep well pump to the outlet of the second stage guide vane. With the Fast Fourier Transform (FFT) analysis, the pressure fluctuation and frequency fluctuation are analyzed under multi-conditions. In this paper, the pressure fluctuation differences between the first stage and secondary are also compared. The numerical results show that the pressure fluctuates at the blade passage frequency, and the maximum amplitude of blade passage frequency occurs in the region from the rotor to the stator when the impeller blade gets close to the guide vane trailing edge, but it decreases rapidly after fluid entering the guide vane. Compared with the steady simulation, the averaged calculated single-stage head of unsteady simulation is more accord with the reality, which is less than the tested head with a relative deviation of 5%.

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The influence of impedance mismatch of the medium with gradient change of impedance on acoustic characteristics

MATEC Web of Conferences ◽

10.1051/matecconf/201928309005 ◽

2019 ◽

Vol 283 ◽

pp. 09005

Author(s):

Bo Hu ◽

Moran Wang ◽

Yimei Du

Keyword(s):

Acoustic Impedance ◽

Acoustic Waves ◽

Propagation Mechanism ◽

Acoustic Characteristics ◽

Impedance Mismatch ◽

Matching Layer ◽

Composition And Structure ◽

New Type ◽

Boundary Impedance ◽

Gradient Change

Medium with gradient change of acoustic impedance is a new type acoustic structure. It is composed of several materials and has a continuous gradient composition and structure whose specific acoustic impedance varies smoothly across the layer. It has been used in various practical situations such as acoustic rectifiers, medical devices, weakening vibration and reducing noise. The purpose of this paper is to investigate the effect of boundary impedance mismatch on acoustic characteristics of gradient impedance media. The propagation mechanism of acoustic waves in medium with gradient change of specific acoustic impedance was calculated by transfer matrix method. By setting the different ratios of the acoustic impedance at interfaces of matching layer, the relationship between specific acoustic impedance mismatch and acoustic characteristics are derived and the corresponding conclusions are drawn. These conclusions provide an idea for the preparation of relevant medium.

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The Microstructure of Shock-Synthesized Diamond

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006163x ◽

1967 ◽

Vol 25 ◽

pp. 324-325

Author(s):

Lucien F. Trueb

Keyword(s):

Single Crystals ◽

Preferred Orientation ◽

High Magnification ◽

Texture Pattern ◽

Shock Process ◽

New Type ◽

Diffraction Diagram

A new type of synthetic industrial diamond formed by an explosive shock process has been recently developed by the Du Pont Company. This material consists of a mixture of two basically different forms, as shown in Figure 1: relatively flat and compact aggregates of acicular crystallites, and single crystals in the form of irregular polyhedra with straight edges.Figure 2 is a high magnification micrograph typical for the fibrous aggregates; it shows that they are composed of bundles of crystallites 0.05-0.3 μ long and 0.02 μ. wide. The selected area diffraction diagram (insert in Figure 2) consists of a weak polycrystalline ring pattern and a strong texture pattern with arc reflections. The latter results from crystals having preferred orientation, which shows that in a given particle most fibrils have a similar orientation.

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New type electron gun with electrostatic and electromagnetic lenses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107459 ◽

1978 ◽

Vol 36 (1) ◽

pp. 62-63

Author(s):

T. Ichinokawa ◽

H. Maeda

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Optimum Condition ◽

Bias Voltage ◽

Electron Gun ◽

Charge Effect ◽

Micro Fabrication ◽

Maximum Brightness ◽

New Type ◽

The Ideal

I. IntroductionThermionic electron gun with the Wehnelt grid is popularly used in the electron microscopy and electron beam micro-fabrication. It is well known that this gun could get the ideal brightness caluculated from the Lengumier and Richardson equations under the optimum condition. However, the design and ajustment to the optimum condition is not so easy. The gun has following properties with respect to the Wehnelt bias; (1) The maximum brightness is got only in the optimum bias. (2) In the larger bias than the optimum, the brightness decreases with increasing the bias voltage on account of the space charge effect. (3) In the smaller bias than the optimum, the brightness decreases with bias voltage on account of spreading of the cross over spot due to the aberrations of the electrostatic immersion lens.In the present experiment, a new type electron gun with the electrostatic and electromagnetic lens is designed, and its properties are examined experimentally.

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A new type of defect structure in 124-superconducting oxide revealed by HREM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089779 ◽

1991 ◽

Vol 49 ◽

pp. 1092-1093

Author(s):

R. Sharma ◽

B.L. Ramakrishna ◽

N.N. Thadhani ◽

D. Hianes ◽

Z. Iqbal

Keyword(s):

Shock Wave ◽

Defect Structure ◽

Neutron Radiation ◽

Weak Links ◽

Defect Structures ◽

New Materials ◽

New Type ◽

Current Densities ◽

Processing Techniques ◽

Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

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ESEM - A multipurpose surface Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144607 ◽

1986 ◽

Vol 44 ◽

pp. 632-633 ◽

Cited By ~ 2

Author(s):

G.D. Danilatos

Keyword(s):

Electron Microscope ◽

Room Temperature ◽

Environmental Scanning ◽

Gas Composition ◽

Saturated Water Vapor ◽

Surface Electron ◽

Current State ◽

Saturated Water ◽

New Type ◽

Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

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Trial production of γ-type energy filtering TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139391 ◽

1995 ◽

Vol 53 ◽

pp. 604-605

Author(s):

Y. Taniguchi ◽

E. Nakazawa ◽

S. Taya

Keyword(s):

Magnetic Energy ◽

Electron Optics ◽

Electron Microscopic ◽

Mass Spectrometers ◽

Ion Optics ◽

Energy Filtering ◽

New Information ◽

New Type ◽

Fringing Fields

Imaging energy filters can add new information to electron microscopic images with respect to energy-axis, so-called electron spectroscopic imaging (ESI). Recently, many good results have been reported using this imaging technique. ESI also allows high-contrast observation of unstained biological samples, becoming a trend of the field of morphology. We manufactured a new type of energy filter as a trial production. This energy filter consists of two magnets, and we call γ-filter since the trajectory of electrons shows ‘γ’-shape inside the filter. We evaluated the new energyγ-filter TEM with the γ-filter.Figure 1 shows schematic view of the electron optics of the γ-type energy filter. For the determination of the electron-optics of the γ-type energy filter, we used the TRIO (Third Order Ion Optics) program which has been developed for the design of high resolution mass spectrometers. The TRIO takes the extended fringing fields (EFF) into consideration. EFF makes it difficult to design magnetic energy filters with magnetic sector fields.

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Development of imaging plate for a TEM and its characteristics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152471 ◽

1989 ◽

Vol 47 ◽

pp. 100-101

Author(s):

N. Mori ◽

T. Oikawa ◽

Y. Harada ◽

J. Miyahara ◽

T. Matsuo

Keyword(s):

Dynamic Range ◽

Protective Layer ◽

High Sensitivity ◽

Imaging Plate ◽

Phosphor Layer ◽

Imaging Device ◽

X Ray Imaging ◽

New Type ◽

Basic Characteristics ◽

Reading System

The Imaging Plate (IP) is a new type imaging device, which was developed for diagnostic x ray imaging. We have reported that usage of the IP for a TEM has many merits; those are high sensitivity, wide dynamic range, and good linearity. However in the previous report the reading system was prototype drum-type-scanner, and IP was also experimentally made, which phosphor layer was 50μm thick with no protective layer. So special care was needed to handle them, and they were used only to make sure the basic characteristics. In this article we report the result of newly developed reading, printing system and high resolution IP for practical use. We mainly discuss the characteristics of the IP here. (Precise performance concerned with the reader and other system are reported in the other article.)Fig.1 shows the schematic cross section of the IP. The IP consists of three parts; protective layer, phosphor layer and support.

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Automatic analysis of Kikuchi diffraction patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172231 ◽

1994 ◽

Vol 52 ◽

pp. 900-901

Author(s):

H. Weiland ◽

D. P. Field

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Spatial Resolution ◽

Relevant Information ◽

Crystalline Materials ◽

Large Size ◽

Transmission Electron ◽

New Type ◽

Diffraction Patterns ◽

Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

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