聚合物辐射裂解分维与其分子链的运动

从分维理论出发，讨论了聚合物在辐射交联反应中裂解度（Ｐ）与辐照剂量（Ｒ）间的关系。发现分维参数与聚合物内聚能密度密度（Ｅｃ）的表征分子链运动的参数分子链横截面积（Ａｐ）之间有一一对应的关系。建议用方程Ａｐ＝（１／Ｄ－０．４４）／０．００９Ｅｃ计算聚合物的Ａｐ值。用本方法计算出的Ａｐ值与文献值较一致。     

内螺纹双球测量的模量近似算法

本文提出一种内螺纹双球测量的近拟计算方法，通过适用模量进行简单计算求得２Ｆ或Ｄ２、Ｄ２单的数值，其计算误差：０≤△２Ｆ≤０．０００１＊Ｐ（ｍｍ）－０．０００１＊Ｐ（ｍｍ）≤△Ｄ２＝△Ｄ单≤０。     

实际分形体维数计算中的RSC问题

在理论上解释了材料断裂表面维数计算中出现的ＲＳＣ问题，提出了建立实际分形体的分维谱Ｄ分析，并且讨论了这种分维谱分析对实际分形体结构研究的重要意义。     

柠檬酸盐法制备纳米晶SrCe0.95Yb0.05O3—α

用柠檬酸酸盐法合成了超细的ＳｒＣｅ０．９５Ｙｂ０．０５Ｏ３－α粉体。使用ＴＧ,ＤＴＡ,ＸＲＤ,ＴＥＭ测试手段,对试样的特性进行了表征,由ＴＥＭ知团粒粒径范围在４０－６０ｎｍ,由ＸＲＤ计算出原始晶粒的精确尺寸１４．７８ｎｍ。     

调制掺杂AlxGa1-xN/GaN异质结磁输运研究

通过低温和高磁场下的磁输运测量,首次在Ａｌ０．２２Ｇａ０．７８Ｎ／ＧａＮ异质结中观察到了舒勃尼科夫－德哈斯振荡的双周期特性,发现在Ａｌ０．２２Ｇａ０．７８Ｎ／ＧａＮ异质结的三角势阱中产生了二维电子气（２ＤＥＧ）的第二子带占据,发生第二子带占据的阈值２ＤＥＧ浓度估算为７．２＊１０＾１２ｃｍ＾－２,在阈值２ＤＥＧ浓度下第一子带和第二子带能级的距离计算为７５ｍｅＶ。     

阳离子型聚氨酯电泳漆的研究

对阳离子型聚氯酯涂料的制造及其电泳工艺进行了研究。结果表明，取ＮＣＯ／ＯＨ≈（１．５￣１．７）：１．０，漆液ｐＨ≈５￣６，电泳时间１￣３ｍｉｎ，在１３０℃左右烘干１０ｍｉｎ时，可得到完全固化的漆膜。     

半导化BST陶瓷晶粒生长的显微表征

采用显微方法研究半导化（Ｂａ０．９Ｓｒ０．１）（Ｔｉ０．９９９Ｎｂ０．００１）Ｏ３陶瓷晶粒生长的动力学因子，同样化学配方的八种样品在１３００℃中保温时间分别为１，３，６，１０，３０，６０，１００和３００分钟，扫描电镜照片（ＳＥＭ）显示八种样品的平均晶粒大小随保温时间延长而增大，经自动图像处理得到的晶粒生长动力学因子不是常数，在生长初期较小（≈１．５）而在生长后期较大（≈３．５），该数据与ＡＢＯ３型构造的陶瓷晶粒生长的计算机模拟结果一致。     

DSA冠状动脉造影分析

目的:分析453例冠状动脉造影诊断结果,探讨冠心病的冠状动脉造影结果及其临床应用价值。方法:应用DSA选择性冠状动脉造影证实的病变直径狭窄≥50%病例365例,依病变狭窄程度,累及冠状动脉部位、数目、形态,冠状动脉优势状况,侧支循环及心肌梗死病例左室壁运动情况进行分析。结果:≥50%狭窄或闭塞365例,冠状动脉右优势型311例,左优势型57例,均衡型85例,单支病变121例,2支病变135例。结论:本组住院患者病例,冠状动脉病变多累及前降支(LAD)44.1%,其次为左回旋支(LCX)及右冠状动脉(RCA);侧支循环形成良好者对左心室功能有保护作用,高质量的DSA设备是开展冠心病介入治疗的重要基础[1]。     

冠状动脉树三维重建理论模型的研究

冠状动脉树的三维信息对于心血管疾病的评价和诊断具有十分重要的意义，研究了基于两幅冠脉造影图像重建三维冠状动脉树的理论模型，首先根据透视投影原理建立一个双平面冠脉造影系统的投影模型．并分析两幅不同角度的造影图像之间的几何变换关系。然后提出一种新型的深度求解方法．最后给出冠状动脉树模型的三维重建结果。     

汉字特征分析与实验字取样策略

以汉字分析为基础,建议选取６ ～１３ 画为笔画数取样范围,把１ ．０ ～４９ ．９ 次／ 百万、５０ ．０ ～４９９ ．９次／ 百万字次作为低、高字频实验汉字的字频取样范围,认为成字部件在上、下、左、右４ 个位置上的出现频率是整字部件识别研究中选择检测部件时的匹配因素之一。２°视角６４ ×６４ 点阵大小黑、宋体汉字图象的大部分频谱能量分布在０ ～８ ．０ 周／ 度的空间频率范围内,应在此范围内进行模式识别研究,并将图像灰度矩阵间的欧氏距离作为汉字图像相似性度量指标。     

Perimeter-Area Relation and Fractal Dimension of Fracture Surfaces

We have theoretically analysed the perimeter-area relation and simulated its application to measuring the fractal dimension of fracture surfaces. It is proved that the fractal dimension Dobtained by slit island method (SIM) is related to the dependence of measured area A(δ) ofthe slit island on yardstick δ. So in some cases, the dimension D obtained by SIM is dependenton yardstick and in other cases independent on yardstick δ. But in all cases, when δ→0 thedimension D obtained by SIM approaches the real fractal dimension (similar dimension) of coastline' of the island. We analysed some experimental data and found some new and interestingcharacteristics of crack propagation in steels.     

Region based coronary artery segmentation using modified Frangi's vesselness measure

Recent research suggests that the cardiovascular diseases (CVDs), seem to be the foremost cause of mortality among the world populace. Three dimensional (3D) imaging modality such as computed tomography angiography(CTA) is a standard noninvasive imaging modality which has great potentials for the visualization of heart and coronary arteries. This article presents a fully automated method for coronary artery extraction using modified Frangi's vesselness measure and region based segmentation. In this article, grayness and gradient based measures are used while computing Frangi's vesselness measure to improve the extraction of coronary arteries. The obtained vesselness measures are utilized for automatically computing the location of ostia. The locations of ostia are then used as starting seed points in region growing segmentation to extract coronary arteries. Three major coronary arteries, namely the left anterior descending artery (LAD), left circumflex artery (LCX) and right coronary artery (RCA) are segmented using the proposed method and the centerlines are extracted for the main coronary branches. The performance of the proposed method is evaluated using 12 3D CCTA data set. The experimental results reveal that during the calculation of modified Frangi's vesselness measure the proposed method gives improved results. The qualitative results obtained during the segmentation stage are also convincing. The average segmentation accuracy and overlap measure of the proposed method are 97.4% and 77.86%, respectively. Hence, the proposed automated approach can detect and extract coronary arteries in CCTA images with high performance.     

掺珍珠岩水泥石孔分形维数及其与孔结构、强度的关系

通过压汞法测试不同龄期掺0-40%珍珠岩掺合料水泥石的孔结构参数,利用分形理论的相关知识研究这些水化物的孔体积分形特征,计算它们的孔分形维数D=3.3～3.5,分析并探讨该水泥石孔分形维数与孔结构参数、抗压强度之间的关系.结果表明水泥石孔分形维数与孔隙率、孔径、孔表面积有密切的关系,随着孔分形维数增大,孔隙率提高,孔径扩大、孔表面积增大,孔结构就越劣化,对应的材料抗压强度下降.因此孔体积分形维数可用于综合评定材料的孔结构特性.     

Fractal Microstructure of Fracture Surfaces and Fracture Energy of Metals

Using a fractat model, we give a new interpretation of the reversed sigmoidal curves of fracture surface profile length obtained in some experiments. It is pointed out that a single parameter (fractal dimension D) is not sufficient to characterize a fractal curve completely. It is shown that the initiator length L0 is also important to characterize a fractal curve. We have derived a formula which correlate the fracture energy with the fractal parameters of the fracture surfaces and analyzed some experimental data.     

分形维数与D6AC钢的韧性

本文研究了超高强度钢Ｄ６Ａｃ的断裂韧性、冲击韧性和拉伸面缩率与断口分形维数的关系。分别用二次电子线扫描和数字图象法测定断裂韧性试样的断口分形维数，得出试样的韧性与分形维数Ｄｓｅ、Ｄ_Ｈ和Ｄ_Ｌ成正比关系，即韧性随分形维数增大而增加。试样断口的粗糙度由夹杂物引起的差异小于金相组织不同引起的差异时，使用数字图象法测得的分形维数与韧性的线性关系优于二次电子线扫描的结果。     

Fracture toughness and crack morphology in indentation fracture of brittle materials

The relationship between the indentation fracture toughness, K _c, and the fractal dimension of the crack, D, has been examined on the indentation-fractured specimens of SiC and AIN ceramics, a soda-lime glass and a WC-8%Co hard metal. A theoretical analysis of the crack morphology based on a fractal geometry model was then made to correlate the fractal dimension of the crack, D, with the fracture toughness, K _IC, in brittle materials. The fractal dimension of the indentation crack, D, was found to be in the range 1.024–1.145 in brittle materials in this study. The indentation fracture toughness, K _c, increased with increasing fractal dimension, D, of the crack in these materials. According to the present analysis, the fracture toughness, K _IC, can be expressed as the following function of the fractal dimension of the crack, D, such that $$In K_{IC} = {1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}\{ In[2\Gamma E/(1 - \nu ^2 )] - (D - 1)In r_L \}$$ Where Γ is the work done in creating a unit crack surface, E is Young's modulus, v is Poisson's ratio, and r _L is r _min/r _max, the ratio of the lower limit, r _min, to the upper limit, r _max, of the scale length, r, between which the crack exhibits a fractal nature (r _min ?r?r _max). The experimental data (except for WC-8%Co hard metal) obtained in this study and by other investigators have been fitted to the above equation. The factors which affect the prediction of the value of K _IC from the above equation have been discussed.     

Three-dimensional fractal analysis of fracture surfaces in titanium–iron particulate reinforced hydroxyapatite composites: relationship between fracture toughness and fractal dimension

Fractal dimension has been considered as a measure of fracture surface roughness of materials. Three-dimensional (3D) surface analysis is anticipated to provide a better evaluation of fracture surface toughness and fractal dimension. The objective of this study was to quantify the fracture surfaces and identify a potential relationship between fracture toughness and fractal dimension in a new type of core–shell titanium–iron particulate reinforced hydroxyapatite matrix composites using SEM stereoscopy coupled with a 3D surface analysis. The obtained results showed that both fracture surface roughness and fractal dimension increased with increasing amount of core–shell Ti–Fe reinforcing particles. The fractal dimension was observed to be a direct measure of fracture surface roughness. The fracture toughness of the composites increased linearly with the square root of fractal dimensional increment (i.e., followed the Mecholsky–Mackin equation well) due to the presence of Ti–Fe particles along with the effect of porosity in brittle materials. The 3D fractal analysis was suggested to be a proper tool for quantifying the fracture surfaces and linking the microstructural parameter to fracture toughness.     

基于ObjectARX的三维分形参数化绘图系统的研究

三维分形图形对自然景物的模拟具有较好的效果,为方便三维分形图形在AutoCAD软件中的使用,对三维分形图形的参数化设计进行了研究,并基于ObjectARX开发了三维分形参数化绘图系统。以三维分形岩石为例介绍了该绘图系统的参数化设计过程,即在研究三角形中点位移法生成分形曲面的基础上,提出了一种改进的中点位移法算法,使其生成为多面体,通过对多面体的参数控制可使之生成形态各异的三维分形岩石,经过着色渲染后,具有较强的真实感。     

水泥断口表面形貌的分形维数定量表征研究

利用分形几何学理论定量表征了几种水泥断口表面的微观形貌特征,并且考察了断口表面分形维数与其抗压强度的关系.结果表明,水泥断口的表面分形维数介于2～3之间,且线性回归分析的相关系数均大于0.98,强的相关性表明实验所选用的水泥断口具有明显的分形特征;水泥的抗压强度与其断口表面分形维数值呈正相关关系.     

水泥砂浆断面形貌像素点法与投影法分形的计算对比研究

为对比分析像素点覆盖法和投影覆盖法计算水泥砂浆断口分形维数的优缺点,采用这2种方法分别计算水泥砂浆在3种不同养护龄期下的断面分形维数,探索分形维数与抗压强度之间的关系。结果表明,像素点覆盖法计算得到的断口分形维数为2.258 0～2.265 6,相关系数为0.988 6～0.989 3,计算精确度高,数值变化区间小;投影覆盖法计算得到的断口分形维数为2.856 0～2.918 9,相关系数为0.921 4～0.935 2,计算精度较差,但数值变化区间大,有利于实际应用,与抗压强度呈良好相关性。