室温固相反应法制备纳米氧化锆及表征

以ZrOCl2.8H2O和NH4HCO3为原料,在适量表面活性剂(PEG-400)存在下,先在室温下充分混合研磨进行固相反应,得到的反应混合物再用水洗去其中的可溶性无机盐并烘干,即得氧化锆前驱体。前驱体经530℃下热解3h即得氧化锆产品,采用TG/DTA,XRD和TEM对前驱体及产品进行了表征。结果表明,所得产品氧化锆为结晶良好、以四方相为主的混合晶相,其平均粒径约为25nm。     

试述冶炼防爆安全

本文阐述冶炼防爆的重要性、迫切性和艰巨性，剖析炉料爆炸物的爆炸机理，对冶炼防爆工作提出一些见解和措施。     

Spectral Method for Thermal Conductivity Calculations

We discuss several post-processing issues in molecular dynamics (MD) calculation of lattice thermal conductivity using the Green–Kubo formula. For crystals with high thermal conductivity such as SiC, converting the MD raw data on heat current fluctuations into thermal conductivity result is non-trivial. One can accelerate the process using Fast Fourier Transform and the spectral method. A few mathematical subtleties are cleared up. Due to finite data length, integration of the correlation function must be terminated before noise takes over; two termination criteria are proposed which give reasonable results for crystalline β-SiC. A simple solvable model that illustrates the above points and can be used for code-checking is presented.     

Analysis of a Gyroscope＇s Rotor Nonlinear Supported Magnetic Field Based on the B-Spline Wavelet-FEM

A supported framework of a gyroscope＇s rotor is designed and the B-Spline wavelet finite element model of nonlinear supported magnetic field is worked out. A new finite element space is studied in which the scaling function of the B-spline wavelet is considered as the shape function of a tetrahedton. The magnetic field is spited by an artificial absorbing body which used the condition of field radiating, so the solution is unique. The resolution is improved via the varying gradient of the B-spline function under the condition of unchanging gridding. So there are some advantages in dealing with the focus flux and a high varying gradient result from a nonlinear magnetic field. The result is more practical. Plots of flux and in the space is studied via simulating the supported system model. The results of the study are useful in the research of the supported magnetic system for the gyroscope rotor.     

Structure study on the thermoelectric materials CexCo4Sb12 (x = 0.5, 1.0) by neutron diffraction

In order to understand the relationship between crystal structure and thermoelectric properties, the neutron diffraction patterns of the thermoelectric materials with the nominal composition Ce_xCo₄Sb₁₂ (x = 0.5, 1.0) were measured at room temperature, the data were fitted by the Rietveld profile refinement method using the Fullprof2k program. It is found that the sample Ce_0.5Co₄Sb₁₂ is composed of two phases, its major phase is CoSb₃ with skutterudite-structure and the Ce atom is not incorporated into the lattice, the impurity is monoclinic CoSb₂. In the case of Ce_1.0Co₄Sb₁₂, the major phase is filled skutterudite, about 10% of the 2a site is occupied by Ce atom, the second phase is monoclinic CoSb₂.     

National and international university departmental Web site interlinking

Although many link patterns have been identified at the university level, departmental interlinking has been relatively ignored. Universities are multidisciplinary by nature and various disciplines may employ the Web differently, thus patterns identified at the university level may hide subject differences. Departments are typically subject-oriented, and departmental interlinking may therefore illustrate interesting disciplinary linking patterns, perhaps relating to informal scholarly communication. The aim of this paper is to identify whether and how link patterns differ along country and disciplinary lines between similar disciplines and similar countries. Physics, Chemistry and Biology departments in Australia, Canada and the UK have been chosen. In order to get a holistic picture of departments' Web use profiles and link patterns, five different perspectives are identified and compared for each set of departments. Differences in link patterns are identified along both national and disciplinary lines, and are found to reflect offline phenomena. Along national lines, a likely explanation for the difference is that countries with better research performances make more general use of the Web; and, with respect to international peer interlinking, countries that share more scholarly communication tend to interlink more with each other. Along disciplinary lines, it seems that departments from disciplines which are more willing to distribute their research outputs tend to make more general use of the Web, and also interlink more with their national and international peers.