Scattering center parameterization of wide-angle backscattered datausing adaptive Gaussian representation

We present a scattering center extraction algorithm to parameterize the backscattered data from complex targets collected over large angular apertures. This parameterization is based on a scattering center model of the target, but includes an aspect-dependent amplitude function for each scattering center. A two-dimensional (2-D) adaptive Gaussian representation (AGR) algorithm is used to extract the position and the amplitude function associated with each scattering center. The algorithm is tested with data generated by the Xpatch radar simulation code as well as chamber measurement data. The results show that a very good compression ratio can be achieved, resulting in a compact scattering center model of the target. Once such model is available, we can easily reconstruct range profiles and ISAR images at any aspect on the same plane with good accuracy     

Protect privacy of deep classification networks by exploiting their generative power

Machine Learning - Research showed that deep learning models are vulnerable to membership inference attacks, which aim to determine if an example is in the training set of the model. We propose a...     

A steel surface defect inspection approach towards smart industrial monitoring

Journal of Intelligent Manufacturing - With the advance in Industry 4.0, smart industrial monitoring has been proposed to timely discover faults and defects in industrial processes. Steel is widely...     

提高钻杆接头冲击功的工艺方法

针对石油钻井关键产品高强度钻杆接头的使用要求,在保证强度指标要求非常高的前提下,研究摸索增加高温正火后再调质的工艺方法,以改善接头材料原始微观带状组织和纤维结构,细化晶粒,提高钻杆接头的冲击功,使该产品力学性能达到API标准的要求。     

国产气相聚乙烯浆液催化剂的工业应用

本文简要阐述了北化院BCS01和上海院SLC-S两种国产气相聚乙烯浆液催化剂的性能、催化剂结构,在Unipol聚乙烯工业装置上应用结果,以及和进口同类催化剂UCAT-J的性能比较。     

Fabricating Water-Insoluble Polyelectrolyte into Multilayers with Layer-by-layer Self-assembly

Summary A water insoluble azo-containing polyelectrolyte (PEAPB6P-AC) was successfully fabricated into multilayer films based on the layer-by-layer adsorption technique by using N, N-dimethylformamide (DMF) as the assembling media. The multilayer growth and structure were studied with UV-vis spectroscopy, and the multilayer surface were imaged with Atomic Force Microscopy and compared with that fabricated in water. The results show that assembling PEAPB6P-AC in DMF can effectively eliminate the hydrophobic aggregation of the azo units and consequently results in a much smoother multilayer surface than that fabricated in water. This improvement to the layer-by-layer adsorption technique, which can avoid some major difficulties faced when assembling hydrophobic polyelectrolytes in aqueous solutions, seems to be a versatile way to fabricate high quality multilayer films when using the hydrophobic even water-insoluble polyelectrolytes as assembling units.     

Studies on membrane formation mechanism by the light transmission technique. I

New parameters, light transmission rate and minimum light transmissions, are proposed. These two parameters reflect the characteristics of the membrane‐forming system and the formation process of the membranes by phase inversion. The relationship between the light transmission and the porous structure of the membrane can be explained by the geometrical optics principles. Variation of the two parameters combining Reuvers's phase separation theory provided a convenient analytical method to predict effectively membrane morphologies. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 174–181, 2003     

Fabrication and amplification of Rhodamine B‐doped step‐index polymer optical fiber

A step‐index polymer optical fiber (SI POF) containing Rhodamine B in poly(methyl methacrylate) (PMMA) has been fabricated by a preform technique. Fluorescence of different fiber lengths were observed and discussed. A high gain (23 dB) for a SI POF with 60‐cm length, 400‐μm diameter was obtained. The Rhodamine B content of the doped SI POF is 5 ppm‐wt. The signal wavelength providing the highest gain for a 60 cm SI POF is around 630 nm, and the optimum fiber length is about 60 cm at 10 kW launched pump power. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 681–685, 2004     

气体控制参数对气体辅助成型产品翘曲的影响

从气体辅助注射成型工艺的角度探讨了气体的延迟时间和第一段压力这两个关键的参数对槽的影响进而对产品翘曲变形的影响，结果表明：虽然通过使用气体辅助注射成型技术能改善产品变形，但并不能完全消除变形；造成产品变形的原因和机理十分复杂，只有进行从设计到工艺的全方位考察才能有效的控制变形，气体手指效应也是造成产品变形的一个重要因素，工艺上可以通过调整延迟时间和气体压力来减小产品的变形量。