熔体旋甩法制备p型填充式方钴矿化合物Ce0.3Fe1.5Co2.5Sb12的微结构及热电性能

采用熔体旋甩法结合放电等离子烧结技术(MS-SPS)制备了p型填充式方钴矿化合物Ce_0.3Fe_1.5Co_2.5Sb₁₂,研究了熔体旋甩工艺对微结构以及热电性能的影响规律.结果表明,较高的铜辊转速和较低的喷气压力有利于提高熔体的冷却速率,使带状产物晶粒细化.薄带经SPS烧结后得到致密、基本单相、晶粒尺寸均匀细小(150—300 nm)的块体.与传统方法制备的试样相比,MS-SPS试样虽然电导率有所降低,但因具有较大的Se     

Influence of pressure on the solid state phase transformation of Cu—Al—Bi alloy

The solid state phase transformation of Cu--Al--Bi alloy under high pressure was investigated by x-ray diffraction, energy dispersive spectroscopy and transmission electron microscopy. Experimental results show that the initial crystalline phase in the Cu--Al--Bi alloy annealed at 750 °C under the pressures in the range of 0--6 GPa is α-Cu solid solution (named as α-Cu phase below), and high pressure has a great influence on the crystallisation process of the Cu--Al--Bi alloy. The grain size of the α-Cu phase decreases with increasing pressure as the pressure is below about 3 GPa, and then increases (P>3 GPa). The mechanism for the effects of high pressure on the crystallisation process of the alloy has been discussed.     

Macro-and Micro-Properties of Two Natural Marine Clays in China

In this paper,macro- and micro- properties of natural marine clay in two different and representative regions of China are investigated in detail.In addition to in-situ tests,soil samples are collected by use of Shelby tubes for laboratory examination in Shanghai and Zhuhai respectively,two coastal cities in China.In the laboratory tests,macro-properties such as consolidation characteristics and undrained shear strength are measured.Moreover,X-ray diffraction test,scanning electron microscope test,and mercury intrusion test are carried out for the investigation of their micro-properties including clay minerals and microstructure.The study shows that:(1) both clays are Holocene series formations,classified as either normal or underconsolidated soils.The initial gradient of the stress-strain curves shows their increase with increasing consolidation pressure;however,the Shanghai and the Zhuhai clays are both structural soils with the latter shown to be more structured than the former.As a result,the Zhuhai clay shows strain softening behavior at low confining pressures,but strain hardening at high pressures.In contrast,the Shanghai clay mainly manifests strain-hardening.(2) An activity ranges from 0.75 to 1.30 for the Shanghai marine clay and from 0.5 to 0.85 for the Zhuhai marine clay.The main clay mineral is illite in the Shanghai clay and kaolinite in the Zhuhai clay.The Zhuhai clay is mainly characterized by a flocculated structure,while the typical Shanghai clay shows a dispersed structure.The porous structure of the Shanghai clay is characterized mainly by large and medium-sized pores,while the Zhuhai clay porous structure is mainly featreed by small and medium-sized pores.The differences in their macro- and micro- properties can he attributed to different sedimentation environments.     

应力-应变过程中海底沉积物微结构变化对其声速的影响

本文阐述了对海底沉积物样品在应力-应变过程中进行同步声学测量的实验工具和方法,分析了采自南海45个站位的海底沉积物样品的实验数据资料,结果表明,沉积物颗粒越粗、孔隙越小、无侧限抗压强度越大,声速越高。沉积物样品在受力应变过程中,声速具有明显的随应力而变化的特征。进一步探讨了不同应变阶段沉积物的声学特征以及应力所导致沉积物微结构变化对其声速的影响过程,这一研究将在石油地质测井和海底工程基底稳定性评价等方面具有重要的应用意义。     

青弹涂鱼Scartelaos virids血细胞的研究

报道了青弹涂鱼 ( Scartelaos virids ) 外周血细胞的显微结构,血涂片经过Wright液染色,可鉴定出红细胞、单核细胞、淋巴细胞、血栓细胞、嗜中性粒细胞和嗜碱性粒细胞,未发现嗜酸性粒细胞.红细胞数量多,圆形,具圆核;血栓细胞体积最小,呈三五个聚集分布;嗜碱性粒细胞体积最大.淋巴细胞大小有三种:大淋巴细胞、中淋巴细胞和小淋巴细胞.在数量上,血栓细胞最多,淋巴细胞次之,单核细胞,嗜中性粒细胞和嗜碱性粒细胞则较少.此外,还见到红细胞、单核细胞可在外周血液中通过直接分裂产生,这说明红血细胞及白血细胞的部分种类也可在外周血直接分裂.     

温控加热下低表面能铝氧化膜的制备及其耐腐蚀初步研究

在氧化铝表面添加有机镀层可以降低其表面能,然而有机镀层具有附着力低、不稳定及污染环境等缺陷.PAOF(多孔氧化铝薄膜)在仿生学上具有类似自然界低表面能生物的表面微结构,为达到进一步提高其表面接触角目的,本研究采用加热冷却等对其进行处理.通过SEM观察,制得的低表面能材料具有约176 nm孔径的规则光滑多孔结构.表面元素...     

砒砂岩的微结构定量化特征研究

应用光学显微照相和图像分析处理技术,对8份砒砂岩样进行了微结构定量化特征分析;运用多元线性回归对砒砂岩物理力学性质与其各微结构定量化参数进行了关联分析.研究表明,砒砂岩的抗压和抗拉强度与其颗粒的大小、形态、分布及排列及孔隙分布密切相关.一般而言,颗粒的粒径、平面分布分维和定向分维越小,砒砂岩的物理力学强度就越高,抗压和抗拉强度就越好.     

岘山垭公路路堑滑坡膨胀土特性及机制探讨

襄樊岘山垭地区膨胀土滑坡是影响公路交通的重大地质病害。曾投入了大量资金进行整治均没有收到良好效果。在探明岘山垭膨胀土滑坡的一些重要性质基础上，利用X射线衍射仪（XRD）、X射线荧光光谱（XRF）分析仪和扫描电子显微镜（SEM），综合常规物理力学实验，对滑坡膨胀土物理性质、微观结构进行了深入研究。以此为基础，探讨了该区膨胀土一些特性在滑坡形成演化中的作用，进一步阐明了该滑坡的形成机制，总结了膨胀土滑坡的一些重要规律，对于深入研究膨胀土滑坡及滑坡整治有十分重要的意义。     

干、湿态单/双链表面活性剂柱撑蒙脱石层间微结构及分子环境比较

以含不同烷基碳链长度(8、12或16个碳原子)的单/双链阳离子表面活性剂对内蒙蒙脱石样品进行了柱撑改性。用XRD和FTIR方法研究了柱撑改性后干、湿样品的层间微结构和分子环境。单链柱撑样品中,烷基链长度增加,柱撑高度也增大。湿样的柱撑高度大多高于干样品,衍射图峰形更为规整,柱撑结构更为均一;双链柱撑样品也是柱撑高度与烷基链长度正相关,但其湿样品的底面间距反而小于干样品。同时,亚甲基伸缩振动的变化趋势与层间距的变化趋势基本一致,即当烷基链长度或数目增加时,有机蒙脱石层间有机相分子的环境更接近于似固态。