芬达过滤器应用于阻燃纤维酸浴处理工艺

针对阻燃纤维生产过程中,阻燃胶通过纺丝机与纺丝浴反应成型后在酸浴中形成的大量白色粘稠状杂质,用常规过滤方式无法有效去除,致使其在管道和设备内形成结垢,而造成生产运行的负荷、设备维护成本大幅度增加的情况,采用1种新的过滤方式——芬达过滤器进行了小试实验。实验结果表明,采用200型号滤布,助滤硅藻土含量为10 g/L,过滤压力控制为0.4～0.5 MPa,再生清洗30 min时,芬达过滤器能够有效去除助燃纤维生产过程中产生的各种杂质,提高了浴液的透明度,使其浊度指标由检测不出数值到过滤后的<50 FTU,达到生产指标要求。

新型带士达过滤器结构和原理

许多过滤过程的目的在于澄清浓度高低不同的悬浮液。法国FiltersGaudfrin公司最近发明了一种新型过滤器——带士达(Diastar)过滤器。据介绍,这种过滤器具有很多优点。例如过滤效率高、滤液澄清度好、操作简单、工作连续、结构紧凑、占用空间少、重量轻和成本低等。

预荷电器技术的研究设计进展

在袋式收尘器中应用预荷电器可以明显提高其收尘性能。本文介绍预荷电器的工作原理和粉尘电晕预荷电的基本物理过程,引用实验图表说明预荷电器对织物过滤器性能的影响以及抑制高比电阻粉尘荷电中的反放电问题,讨论了粉尘比电阻和电晕电流密度对反放电现象的影响和有关脉冲猝晕,高强度离子器等预荷电器结构设计的新进展。

Segments-based progressive TIN densification filter for DTM generation from airborne LIDAR data

Airborne light detection and ranging( LIDAR) has revolutionized conventional methods for digital terrain models( DTMs) acquisition. Ground filtering for airborne LIDAR is one of the core steps taken to obtain a high quality DTM. This paper presents a segments-based progressive TIN( triangulated irregular network) densification( SPTD) filter that can automatically separate ground points from non-ground points. The SPTD method is composed of two key steps: point cloud segmentation and clustering by iterative judgement. The clustering method uses the dual distance to obtain a set of seed points as a coarse spatial clustering process. Then the rest of the valid point clouds are classified iteratively. Finally,the datasets provided by ISPRS are utilized to test the filtering performance.In comparison with the commercial software Terra Solid,the experimental results show that the SPTD method in this paper can avoid single threshold restrictions. The expected accuracy of ground point determination is capable of producing reliable DTMs in the discontinuous areas.

Designing and implementation of variance-dependent Goldstein radar interferogram filtering

The variance-dependent Goldstein radar interferogram filter takes into account the information of both interferometric coherence and multilook factors,and can produce very consistent results for interferograms generated under a wide variety of multilook factors and with very different noise level.However,the filter is a bit complicated and its application is still very limited.We present the designing and implementation of the variance-dependent Goldstein radar interferogram filtering,emphasizing on the logic flow,the generation of look-up table,the determination of filtering parameter,and the handling of edge information loss.Experiments with real interferograms are provided to demonstrate the applications of the designed filtering.Comparisons with the result of the coherence-dependent Goldstein filter show that improvements from 18.4% to 36.9% are achieved when the variance-dependent filter is used,and the noisier the interferogram,the greater the improvement.

APULSECOMPRESSORIMPLEMENTATIONWITHDSPFORSMALLTBPRODUCTLFMWAVEFORM

This paper describes a pulse compressor implementation with DSP for small Time Bandwidth (TB) product Linear Frequency Modulation (LFM) waveform. It contains the digital generation of the LFM waveform and the digital internally Hamming weighted compression filter. Two methods for suppression of time sidelobe of the digital pulse compressor are employed. First, the LFM waveform is modified by using cubic phase pre distortion for reducing the effect of Fresnel ripples in small TB product LFM waveform. Secondly, anti aliasing filter is used before A/D converter for reducing spectrum skirt level of the returned LFM waveform. The parameters of the compression filter implemented with IMSA100 DSP are programmable. The experiments show that the peak time sidelobe level of the digital pulse compressor is less than -32 dB for TB product of 20.

InSAR Kalman Filter Phase Unwrapping Algorithm Based on SRTM DEM

PU （phase unwrapping） is the key step and important problem in DEM （digital elevation model） extraction and the measurement of surface deformation of InSAR （Interferometric synthetic aperture radar）. The CKFPUA （conventional Kalman filter phase unwrapping algorithm） can obtain reliable results in the flat terrain areas, but it caused error transmission not making the accurate inversion of surface deformation information in the steep terrain. Considering this situation, so it needs to introduce topographic information for guiding phase unwrapping. Here the 90 m resolution DEM data have been used and it is obtained by SRTM （shuttle radar topography mission） measured jointly by NASA （National Aeronautics and Space Administration） and NIMA （National Imaging Mapping Agency） of U.S. Department of Defense. This paper presents a SD-KFPUA （Kalman filter phase unwrapping algorithm） based on SRTM DEM. With SRTM DEM directing InSAR image to implement phase unwrapping, the speed and accuracy are improved. By analyzing with the conventional Kalman filter phase unwrapping algorithms, it is shown that the proposed method can achieve good results in particular to improve unwrapping accuracy in the low coherence region.

Distance-Limited Filter for Extracting Ground Points

The extraction of points on the bare earth from point clouds acquired by airborne laser scanning is one of the most important steps for the generation of digital terrain models （DTM）. This process is called ＂filtering＂. However, most of the cur- rent filters erode the bare earth in steep sloped landscapes and at discontinuities, and they retain low vegetation. Therefore, a new filtering method for extracting ground points based on a distance limit is proposed in this paper. The angle criterion is used to assure the robustness of the algorithm. The experimental results show that the proposed filtering method can effectively derive the ground points from point clouds in complex urban areas.