Dense and core-rim structured B4C-TiB2 ceramics with Mo-Co-WC additive

B₄C-TiB₂ ceramics (TiB₂ ranging 5~70 vol%) with Mo-Co-WC as the sintering additive were prepared by spark plasma sintering. In comparison with B₄C-TiB₂ without additive, the enhanced densification was evident in the sintered specimen with Mo-Co-WC additive. Core-rim structured grain was observed around TiB₂ grains. The interface of the rim between TiB₂ and B₄C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B₄C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B₂ rim around the TiB₂ core may occur as a result of the solid solution and dissolution-precipitation between TiB₂ phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB₂ content increased, alongside the decreased hardness. B₄C-30 vol% TiB₂ specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m^1/2.     

High-resolution electron microscopy of the twinning and intergrowth in Ca4Al6SO16 and Ca3SrAl6SO16

The microstructures of unhydrated calcium aluminosulphate Ca₄Al₆SO₁₆ and Ca₃SrAl₆SO₁₆ have been studied by high-resolution electron microscopy (HREM). The results showed that twinning and twinned slabs could be introduced taking the [1 1 2] direction as the twin axis so that it seems to be coincident with the law of twinning formed in body-centred cubic structures. A previously reported superlattice with a repeat period twice that of the fundamental structure along the 〈1 1 0〉 direction has also been found in both matrix and twin variants. The close intergrowth of Ca₃SrAl₆SO₁₆ and another phase, possibly Sr₃Al₂O₆ existing as an inclusion between these two twin variants, was determined and clearly revealed by electron diffraction and HREM images. The coherent interphase boundaries and orientation relationship between them can also be deduced.     

高温皂碱练与酶制剂练精干绵性能比较

通过测试比较，分析了酶制剂练、高温皂碱练由精练方法不同而造成纤维在微观、外观、机械、吸湿及电学等方面的异同点。提出酶制剂练对提高纤维梳折、提高成纱品质、提高劳动生产率、降低工人劳动强度等方面均优于高温皂碱练，是精练工程改造方向之一。     

铁钴钒软磁合金损耗谱的分形结构

研究了铁钴钒软磁合金的铁芯损耗，发现铁芯损耗谱具有分形结构。讨论了带材厚度和磁感应强度对分形维数Ｄｆ的影响。     

丙烯酸酯聚氨酯紫外固化凝胶生成动力学研究

采用丙烯酸酯聚氨酯和二苯甲酮/安息香乙醚复合光敏剂,对该体系紫外光固化反应的凝胶生成动力学进行分析。用红外光谱定量测定光聚合过程的变化,发现光聚合反应主要是以双键打开,交联为特征的,并得出1408cm~(-1)双键吸收峰随光照时间而变化的关系式:P_(c=c)=0.325 t~(0.135)。临界凝胶点可由双键反应程度与凝胶分数之间关系外推得到,凝胶点后,体系中存在一个凝胶与溶胶之间分配关系,此时凝胶与溶胶共存,凝胶中双键反应程度P_(A(g))>总双键反应程度P_A>溶胶中双键反应程度P_(A(S))。随着凝胶增加,P_A和P_(A(g))逐渐上升,而P_(A(s))下降。此体系的紫外固化实验工作曲线与理论值基本一致。     

HVS：一个半现实全景图时空模型

利用实景图象组成具有空间感和时间感的虚拟空间，我们称之为半现实。这种具有空间“上下文”和时间“上下文”能力的半现实全景图可以应用于许多方面。文中描述了这种半现实ＨＶＳ的建模思想，给出了组成时空座标系的方法，并且讨论了实现中的若干问题。     

A 20-Gb/s silicon bipolar 1:4-demultiplexer IC

This paper presents a 20-Gb/s 1:4-demultiplexer for future fiber-optic transmission systems. It uses an 0.4-μm emitter double polysilicon 21-GHz f_T Si bipolar foundry process. This is the highest data rate of a 1:4-DEMUX reported so far in any technology. The 1:4-DEMUX features a tree-type architecture with one frequency divider and a channel switch circuit. The circuit design was carefully optimized to achieve high speed and moderate power dissipation. It consumes 1.4 W with a single -4.5-V supply     

第三届亚洲室内设计联合会东京年会

中日韩亚洲室内设计联合会(AIDIA)第三届年会2004年10月15日在日本东京大景象国际会议中心举行,这是中日韩三国室内设计专业团体于2000年5月在汉城发起组织联合会之后的第三次年会。上次会议在我国西安举行,同时开始由我学会担任轮值主席国,为期两年。这次东京会议与13日就开幕     

Equilibrium and crystallographic measurements of the binary tetrahydrofuran and helium clathrate hydrates

Clathrate compounds are crystalline materials formed by a physical interaction between host and relatively light guest molecules. Various types of nano-sized cages surrounded by host frameworks exist in the highly unique crystalline structures and free guest molecules are entrapped in an open host-guest network. Recently, we reported two peculiar phenomena, swapping and tuning, naturally occurring in the hydrate cages. Helium, one of the smallest light guest molecules, must be the challengeable material in the sense of physics and moreover possesses versatile applications in the field of superconductivity technology and thermonuclear industry. In this regard, we attempted for the first time to synthesize helium hydrates at moderate temperature and pressure conditions. According to inclusion phenomena, helium itself normally cannot form clathrate hydrates due to being too small molecularly without the help of hydrate former molecules (sI, sII, and sH formers). In this study, the hydrate equilibria of the binary clathrate hydrate containing tetrahydrofuran, helium, and water were determined at 2, 3, 5.56 THF mol%. Direct volumetric measurements were also carried out to confirm the exact amount of helium captured in the hydrate cages. Finally, the crystalline structure of the formed mixed hydrates was identified by powder X-ray diffraction, resulting in structure II.