Dielectric Relaxation in Bi_2BaNb_2O_9 Ceramic

A very strong dielectric relaxation was observed in Bi_2BaNb_2O_9 ceramic.The temperature differencebetween the maximum dielectric constant temperatures T_m measured at 1 kHz and 100 kHz is 65℃.which is about 2-4 times that of relaxor ferroelectrics.The possible mechanism of the anomalousdielectric relaxation was discussed.     

偏心带状线特性阻抗的计算

本文应用复变函数法导出了偏心带状线特性阻抗的解析公式,并进行了实际计算,数值结果与文献值吻合较好.     

基于色度畸变和纹理特征的阴影消除方法

从图像序列中精确地提取运动目标是许多计算机视觉应用中的核心部分,但由于运动目标阴影的存在,会导致目标形状的扭曲、目标的相互连接等问题,对分割和提取运动目标造成很大的困难.为了精确地提取运动目标,提出一种利用色度畸变和纹理特征进行阴影消除的方法.采用混合高斯分布建立自适应背景模型,运用背景减除的方法分割出运动区域,并分析了场景点在存在阴影前后色度的分布规律以及纹理的互相关性,从而消除运动目标的阴影.分析和实验表明,该算法抗干扰能力强,对于室内和室外光照条件下的阴影都能有效地消除,并且所需设置的参数少,复杂度较低,易于实现实时运动图像处理.     

结晶性织物防水透湿整理剂的制备及应用

采用亲水性聚醚型形状记忆聚氨酯整理剂对织物进行防水透湿整理 ,试验结果表明 ,采用这种聚氨酯涂层的织物透湿量达到 3 5 0 0 g/m2 ·2 4h以上 ,防水性接近耐 4～ 5kPa水压 ,被水润湿的速度约为 15°/min ,对环境温度的响应范围是 11～ 2 1℃。对使用该涂层剂研制“智能型”防水透湿织物的可能性进行了分析     

氨基甲酸酯土豆淀粉浆料的合成与浆纱性能

系统研究了氨基甲酸酯土豆淀粉浆料的合成与浆纱性能。指出作为纺织浆料用的氨基甲酸酯淀粉的取代度应在0．06～0．07之间，最佳的合成工艺条件为：浸泡时间1h；pH值为6；尿素占淀粉用量的6％；焙烘温度150℃；焙烘时间1．6h。     

基于FD—TD的矩形波导中多层有耗介质柱数值分析

本文采用二维ＦＤ－ＴＤ分析加载有耗介质柱的矩形波导Ｈ面不连续性，对多层有耗介质柱体在波导中的不连续性引起的谐振以及在介电常数测量方面的应用进行了深入的讨论，数值与已有文献结果相符。由于本文方法具有推导简单、计算省时的特点，所以是研究波导介质不连续性的一种有效手段。     

SURFACE STATE AND CATALYTIC ACTIVITY OF ACTIVATED AMORPHOUS Fe_(80)Zr_(12)B_8 ALLOY

The depth profile of composition,chemical state of elements and morphology of as-received and activated amorphous Fe_(80)Zr_(12)B_8 alloy ribbons have been studied by meansof Auger electron spectroscopy,X-ray photoelectron spectroscopy and scanning Augermicroprobe combined with Ar ion bombardment.Both dull and free sides of the as-received ribbons were covered with an iron oxide layer.While a pronounced surfacesegregation and oxidation of B and precipitation of microcrystalline α-Fe particleswere observed on both sides of activated ribbons,B and Zr were oxidized selectivelyin subsurface layer.On both sides of ribbons,a porous surface structure formed. TheBET surface area was measured to be increasing from 0.11 to 2.68 m~2/g.The principalmechanism of in situ activation has been discussed.     

CCT-DIAGRAMS OF Si-Mn-Mo BAINITIC STEELS

CCT-diagrams of Si-Mn-Mo bainitic steels have been determined.With Mo 0.25%,thehigh-temperature transformation of the steel shifts large to the right,and the bainitic trans-formation region becomes a“flat topped C-curve”at cooling rate in wide range.Si in the steelmay cause shift of the bainitic transformation region towards the right,and of thepro-eutectoid ferritic transformation region towards the left.Mn may delay the high temper-ature transformation more violently than the bainitic transformation.     

MICROSTRUCTURAL CHARACTERIZATION OF Nd_(34)Fe_(60)O_(6) ALLOY

The microstructure of Nd_(34)Fe_(60)O_6 alloy was characterized by means of scanning electronmicroscope,Auger electron multiprobe,X-ray diffraction,differential thermal analysesand thermomagnetic analyses.It is found that the equilibrium microstructure of the alloy iscomposed of a Nd_2Fe_(17) matrix,an oxygen-containing Nd-rich phase anda Nd-Fe-O ternary ferromagnetic phase (referred to T_1).This phase forms via aperitectic reaction between Nd_2Fe_(17) and Nd-rich phase at 840 ℃.Its composition isaround Nd_(36)Fe_(54)O_(10),and Curie temperature 180℃.The X-ray diffraction peaks can beindexed on a tetragonal cell with lattice parameter of a=0.771nm and c=2.228nm.Thisstable phase is believed to be transformed from the metastable phase (A_1) in Nd-Febinary system as a result of oxygen introduced.     

MICROSCOPIC KINETICS OF NON-EQUILIBRIUM SOLIDIFICATION

Theoretical model for non-equilibrium solidification is constructed with consideration of diffuse interface and muliphase fhctuation.It can be degenerated to A(?)i(?) continuousgrowth model in the case of mono-atomic approximation.For large underecooling, thechange of heat eapacity should not be neglected and it usually gives an increase in the inter-face partition coefficient.Solute trapping may happen at a rather slow growth rate com-pared with that predicted by other models,because the undercooling and structural relaxa-tion ahead of the S/L interface lowers the interfacial diffusivity to a great extent. Phasefluctuation has two contending effects,decrease in energy barrier and increase in atomicdragging,therefore exerts dual influences on the partition coefficient.