基于颜色共生矩阵的纹理检索算法MCM

描述了一种基于颜色共生矩阵的纹理检索算法MCM,主要包括颜色共生矩阵纹理特征提取算法以及纹理特征的相似性度量函数,给出了利用MCM算法检索图像库的实例.通过MCM算法提取的特征除了反映图像的纹理关系外,还综合了其颜色构成特征,部分建立了与人的视觉感知之间的对应关系.实验表明,MCM算法优于一般的灰度共生矩阵纹理检索算法,并且具有较好的检索效果.     

催化剂和供氢剂及其前身物对二苯甲烷裂化反应的影响

在无搅拌的高压静态反应器及 4 4 0℃条件下对二苯甲烷作为渣油的模型化合物分别进行二苯甲烷的临氮、临氢反应和临氢催化反应 ,考察了在供氢剂及其供氢剂前身物或溶剂 3类添加物存在下二苯甲烷的临氮、临氢和临氢催化反应。分析了临氮热反应、临氢热反应和临氢催化反应中催化剂和供氢剂及其前身物对二苯甲烷裂化反应的影响程度。结果表明 ,气相氢能加速二苯甲烷的裂化反应 ,而供氢剂抑制其裂化。不同的供氢剂对二苯甲烷裂化有不同程度的抑制能力 ,供氢剂的供氢性能越强 ,抑制效应越强。在催化加氢体系中加入油溶性催化剂二烷基二硫代氨基甲酸钼和环烷酸铁 ,对促进二苯甲烷裂化非常有效 ,且前者的裂化活性远高于后者。供氢剂前身物在催化加氢体系中可以转化为供氢剂 ,从而起到抑制二苯甲烷裂化的作用     

多孔介质微观孔隙结构分形特征及分形系数的意义

依据孔隙结构的球体模型和毛管束模型 ,推导出两种模型的孔隙体积表达式和两种模型分形维数间的关系式。计算结果表明 ,基于毛管束模型的分形维数总比基于球体模型计算的分形维数小 1,分形系数的物理意义在于它反映了孔隙的发育程度。基于毛管束模型 ,利用压汞数据计算了西峰油田长 8储层多孔介质微观孔隙的分形维数 ,同时给出了分形维数与孔隙度、渗透率等地层参数的关系曲线。分析结果表明 ,该区孔隙结构具有分形特征 ,分形维数为 1～ 2。分形维数越大 ,多孔介质微观孔隙分布的非均质性越强 ;分形系数越大 ,孔隙越发育 ,储层物性越好。     

Self-assembly of N-3-γ-pyridyl Aza[60]fulleroid on Au(111)

Self-assembled monolayers of novel C60 derivative, N-3-γ-pyridyl Aza[60]fulleroid (C60Py), on Au(111) were studied by a scanning tunneling microscope under ultrahigh vacuum (UHV). C60Py molecules were assembled on Au (111) via pyridyl nitrogen-Au interaction. The sole assembly of C60PY molecules on Au (III) only exhibited randoml aggregation of C60PY even the films were annealed at 50 and 105℃ .By co-assembling with benzyl mercaptan (BM), the C60PyBM films showed highly dense aggregation, but C60Py assemblies still had disordered structure. After the co-assembled C60Py-BM films were annealed at 50℃, BM molecules were partially desorbed, but the assembly of C60Py remained without obvious change. After the co-assembled C60Py-BM films were further annealed at 105℃, the C6oPy monolayers with ordered structure were obtained, while the BM molecules were nearly thoroughly desorbed from the surface. Here, the BM molecules play a key role as a surfactant in the formation of the ordered C6oPy monolayer.     

葱莲凝集素基因的克隆

RACCE－PCR技术从葱莲叶片中克隆出葱莲凝集素的全长cDNA，通过比较葱莲同其它石蒜科植物的凝集素基因序列和推测的氨基酸序列，发现葱莲凝集素基因编码一具有信号肽的前体蛋白，葱莲凝集素同其它石蒜科植物凝集素一样为具有3个甘露糖专一结合盒的凝集素。     

基于时限信号重构技术的桥梁动挠度惯性测量方法

以惯性测量原理,用地震式低频振动传感器测量桥梁动挠度。利用信号恢复技术,对地震式低频振动传感器因频率特性而畸变的输出作补偿处理。讨论系统存在零点时的恢复技术,及噪声下信号恢复处理的不适定性问题。以铁路桥梁动挠度的部分时域特征,采用时限信号低频频谱重构技术,外推信噪比差的部分低频谱线,有效地反演原始信号。本文为列车激励下桥梁空间振动形态提供了十分便捷有效的测量方法。     

合金化与形变热处理对铜合金弹性模量的影响

研究了微量元素及形变热处理工艺对铜基合金弹性模量的影响．研究结果表明：添加致密度参数Ｊ（Ｊ＝１／（ＶＤ））大的元素（如Ｂ和Ｆｅ）能使铜基合金固溶体晶格收缩;通过大的冷变形和时效处理等工艺措施使β相析出,起到强化基体的作用,并能使合金的弹性模量有所提高．     

楝属植物质杀虫剂对中华稻蝗生物活性研究(Ⅰ)拒食作用

拒食作用试验结果表明,楝属中的三种植物质杀虫剂的各种抽提物对中华稻蝗(Oxrya chinensis Thunbery)不同龄期均具有拒食作用.印楝油(印度产)在0.2%浓度下拒食率可达80.46%.在苦楝抽提物中,以吉楝果甲醇抽提物拒食活性最强,“MeOH C.B.”和“CB—G”在1%浓度下拒食率均达95%以上.印楝种子水悬液和川糖果水悬液对稻蝗拒食作用,也显示出较高的效果.试验说明,应用这些植物质杀虫剂防治蝗虫具有很大的潜力,值得进行深入研究和开发应用.     

New UWB imaging algorithm for multiple targets detection

Because the conventional ultra wideband(UWB) radar imaging algorithm cannot meet the demand in the capability of multiple targets detection,a novel UWB radar imaging algorithm based on the near field radiation theory of dipole is presented.On the foundation of researching the principle of a time domain imaging algorithm,the back projection(BP) algorithm is derived and analyzed.Firstly,the far field sampling data are transferred to the near field sampling data by using the near field radiation theory of dipo...     

Effect of one-step aging on microstructure and properties of a novel Al-Zn-Mg-Cu-Zr alloy

The effect of one-step aging temper on the mechanical properties,electrical conductivity and the microstructure of a novel Al-7.5Zn-1.6Mg-1.4Cu-0.12Zr alloy has been investigated.The results indicated that with elevating the aging temperature from 100°C to 160°C,the aging response rate was greatly accelerated,and the UTS at peak aging condition decreased,while the corresponding TYS increased.However,the electrical conductivity of the alloy became higher.After aging for 24 h at 120°C,the peak UTS and TYS values were achieved as 591 MPa and 541 MPa,respectively;but the alloy achieved a lower conductivity,20.4 MS/m.When T6 temper was performed at 140°C for 14 h,the UTS decreased only by 1%of the former,whereas the TYS and the electrical conductivity increased obviously,which were up to 559 MPa and 22.6 MS/m,respectively.The major strengthening precipitates of the peak-aged alloy were GP zones andη′phase.The precipitates in both the matrix and the grain boundary became coarser with rising aging temperature.There were obvious PFZs along the grain boundary both in T6 conditions aged at 140°C and 160°C.