聚硅酸铁混凝剂对腐殖酸的氧化性能研究

以水玻璃、硫酸亚铁及氯酸钠为原料，采用独特共聚工艺制备了聚硅酸铁（PSF）混凝剂，考察了PSF对腐殖酸（HA）的氧化性能及高岭土对被氧化HA的吸附效果，同时进行了复合铝铁（PFA）的对比试验。结果表明，PSF是一种具有氧化性能的混凝剂，因其改变了HA的分子结构，从而使HA的表面性质以及HA／水溶液的界面性质发生变化，使亲水性HA转化为憎水性HA,导致高岭土对其吸附性能增强；不同pH值下PSF均有良好的氧化性能，而PFA仅在酸性时具有氧化性；pH值对HA、PSF、高岭土之间的络合模式具有较大影响，中性下时DOMs的去除效果较好。     

Bone density aspects in the biomechanical behavior of ALIF using cylindrical cages and PSF

Cage subsidence and loosening increase with a decrease of bone density. Thus, the stabilization of spinal segments may be dependent on density of cancellous bone. The aim of this study was to investigate the effects of bone density on the biomechanical behavior of the ALIF with cylindrical cages and PSF. Nonlinear numerical analysis was carried out by means of finite element method, and various Young’s moduli those have been described by the bone density were employed for the calculation. The range of motion was increased by 120% with decreasing of the density. Relative slip distance increased by 810% at the bone-cage interface and by 1750% at the bone-screw interface with a decrease of the density. Continuous cage subsidence, cage loosening, screw loosening and screw failure would occur particularly during an excessive flexion and/or an excessive axial rotation. The excessive low density would mainly cause pediclescrew loosening due to the remarkable screw slip. In the case of excessively reduced density, therefore, further study is required in order to investigate how to improve the current PSF for the segmental stability. This paper was recommended for publication in revised form by Associate Editor Young Eun Kim Young Kim received a B.S. degree in Mechanical Engineering from Chonnam National University in 1986. He then went on to receive his M.S. from KAIST and Ph.D. degrees from University of Wisconsin-Madison in 1991 and 1996, respectively. Dr. Kim has a lot of industrial experiences over 10 years (1996–2006). Dr. Kim is currently a Research Professor at the School of Mechanical Engineering at Hanyang University in Seoul, Korea. Dr. Kim’s research interests are in the area of spinal biomechanics, mechanical design, product design, environmental machinery design, application of porous materials and ballistic impacts.     

基于图像模糊度的雾含水量测量方法

雾含水量是研究和定义雾结构的一个重要因子，是与天气密切相关的重要气象物理量。目前国内外对雾含水量的测量主要还是采用人工采样方式，相当费时费力。该文通过建立雾中景物成像的多次散射模型，提出了利用图像模糊度测雾含水量算法，介绍了基于该算法下的全自动雾含水量测试系统的构成。仿真结果表明运用此算法能获得令人满意的结果。     

Comparison of thermal degradation characteristics of poly(arylene sulfone)s using thermogravimetric analysis/mass spectrometry

Thermal degradation of poly(arylene sulfone)s had been studied by the combination of thermogravimetric analysis/mass spectrometry (TG/MS) with pyrolysis/gas chromatography/mass spectrometry (Py‐GC/MS) techniques. Through these two methods, the pyrolysates from poly(ether sulfone) (PES) and polysulfone (PSF) were identified in 11 and 21 sets of evolution curves, respectively, from room temperature to 900 °C. Among these pyrolysates, 12 products from PES and 25 products from PSF were obtained. The major mechanism for both PES and PSF was one‐stage pyrolysis involving main chain random scission and carbonization with evolution of SO₂ and phenol as major products. Although the initial thermal stability of PES was lower than that of PSF, the formation of sulfide groups in the condensed phase from PES, through reduction of sulfone group by hydrogen radicals, increased the fire retardation behavior of PES. In PES, the ether and sulfone groups showed similar thermal stability. The thermal stability of functional groups in PSF were in the order of sulfone < ether < isopropylidene group. The scission of the ether group in PSF, with evolution of phenol as the major product, reached maximum evolution amount at the temperature of the maximum thermogravimetry loss of TG (T_max). The scission of isopropylidene groups at high temperature (>580 °C) evolved higher mass derivatives that lower the fire retardancy of PSF. By using a simplified kinetic model, PES showed maximum activation energy with a conversion ratio of 0.2–0.3, which implies a high fire retardant effect of sulfide formation in PES. A comparative study with the proposed model and experimental data showed the theoretical pyrolysis curves to be in agreement with the experimental curves for PES and PSF pyrolysis, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2387–2398, 2001     

聚砜-聚对苯二甲酸乙二醇酯嵌段共聚物对聚砜/半芳族聚酯液晶共混体系的增容改性作用

合成了具有不同分子量的PSF－PET共聚物。考察了这种共聚物对于聚砜／热致液晶聚合物（PSF／TLCP）共混物的增容改性效果。这种增容剂的增容改性效果与其分子量的大小有关,分子量较大共聚物的增容效果较好。与未增容体系相比,只加入少量分子量较高的PSF－PET共聚物,原位复合体系的多项力学性能得到明显提高,液晶聚合物分散相分散更均匀,且仍然以微纤状分散在基体中。     

面阵焦平面探测器扫描图像模糊的退化模型及复原

提出并验证面临探测器扫描图像退化模型的点扩展函数,并运用该点扩展函数对扫描模糊图像进行复原。     

入射激光对激光扫描共聚焦显微镜分辨率的影响

利用点扩散函数(PSF)研究了入射激光的偏振态和光束的束腰直径对激光扫描共聚焦显微镜(LSCM)分辨率的影响。根据Wolf和Richards的矢量衍射积分,建立了LSCM N-1层界面下的照明PSF模型,对零层和两层界面下的PSF进行了计算分析。结果显示:在零层界面下,圆偏振光入射的PSF在xy平面内关于焦点旋转对称,半峰全宽为0.43μm,x向线偏振光入射时PSF在x、y方向的半峰全宽分别为0.48,0.39μm;在圆偏振光入射的PSF中,高斯光束充溢系数为0,1,2,5对应的半峰全宽分别为0.43,0.47,0.62,1.49μm。在两层界面下,当探测深度为50μm时,圆偏振光PSF的半峰全宽为0.26μm,x向线偏振光入射时PSF在x、y方向的半峰全宽分别为0.28,0.24μm;在圆偏振光入射的PSF中,充溢系数为0,1,2,5对应的半峰全宽分别为0.26,0.28,0.32,0.68μm。以上计算结果表明,和线偏振光相比,圆偏振光在一个方向的分辨率优于线偏振光,在相垂直的另一个方向的分辨率弱于线偏振光,圆偏振光PSF在xy平面内关于焦点旋转对称,得到了较好的成像质量;物镜入瞳直径与激光束腰直径比值越小,LSCM的分辨率越好。     

近距离大转角目标超宽带ISAR成像

该文采用冲激体制超宽带时域方法,研究近距离大转角目标的高分辨率逆合成孔径成像,针对目标大转角带来的严重的散射点越分辨单元走动、固有的转动角度离散化带来的数据误差以及接收回波过程中的噪声污染等问题,提出了具有强鲁棒性的频域加窗滤波球后向投影算法(Windowing Filtered Spherical Back Projection, WFSBP),从几何上阐明了滤波对转动角度离散化带来的数据误差的补偿作用,分析了大转角目标成像点扩散函数,进而讨论了发射单频信号时的高分辨成像,通过仿真和实测数据进行验证,结果表明,该算法优于传统的后向投影算法,对大转角目标能得到高质量高分辨率的图像。     

薄雾模糊图像的恢复算法研究

成像光波受到大气中薄雾干扰,形成模糊图像.文章基于最大熵算法,分析了成像系统点扩展函数畸变导致图像模糊的机理,提出了一种有效的薄雾模糊图像的恢复算法.     

基于点扩散函数的多聚焦图像融合方法

提出了一种新的基于点扩散函数的多聚焦图像融合算法,采用高斯函数对多聚焦图像进行多次卷积,通过与原近似误差图像的比较,得到聚焦清晰和模糊区域,采用形态学方法将其分割出来,并根据最大值融合规则对其进行了融合。试验结果表明,该算法可将图像分割成多个聚焦区域,边缘清晰、融合效果良好。