传统与创新：试析日本现代建筑传统继承的方式

文章分析，探讨了日本现代建筑传统继承的方式，认为其具有体现民族文化特征和建筑文化创造发展的综合意义。     

Application of dynamical system scaling method on simple gravity-driven draining process

Scaling analysis is widely used in the design of nuclear reactor passive safety systems to ensure that the scale-down test facilities can accurately capture the important phenomena in the prototypic system. In this study, the scaling distortion of a gravity-driven draining system has been analyzed with Hierarchical Two-Tiered Scaling (H2TS) method, based on the initial static characteristic values. In the draining process, however, the key parameters may vary with respect to time, leading to a certain level of scaling distortion. To evaluate the time-dependent scaling distortion, a Dynamical System Scaling (DSS) method is applied. Through comparisons of scaling results of the two scaling methods, it is concluded that the H2TS method can effectively scale the gravity-driven draining process in different geometric sizes, if the variations in the friction factor is negligible. As the draining process slows down, accompanied by an increase in the friction factor, the distortions in water level and in discharge velocity become significant, especially at the end of the draining process in a model of relatively small geometry size. This preliminary study demonstrated the process of scaling distortion analysis using the DSS identity method, and could shed light to the scaling distortion evaluation of testing programs.     

Synthesis and structure study of copolymers from thiadiazole fused indolocarbazole and dithienosilole

We report synthesis and characterization of two D-A polymers (PSDT-C12 and PSDT-EH) with different side chains. Both polymers are based on alternate 12,13-dioctyl-indolo[2,3-a][1,2,5]thiadiazolo[3,4-c]carbazole (TDZIC) and dithienosilole derivative units in polymer main chain. We used TDZIC to enlarge the 2D conjugated plane of acceptor monomers by fusing benzothiadiazole (BT) unit with an indole unit having alkyl groups. PSDT-C12 exhibited 10 nm redshift compared to PSDT-EH in solid films, while their absorption spectra were almost identical in solutions. Since the backbone and side chains on the indolocarbazole group are the same, the redshift on PSDT-C12 could be resulted from the dodecyl (C12) side chain on the dithienosilole unit and different molecular weight between these two polymers. PSDT-C12 has a larger molecular weight than PSDT-EH. Therefore possibly both side chains and molecular weight contributed to the difference in the absorption spectra in solid films. The straight C-12 side chain has less steric hindrance than the branched EH side chain in solid films. PSDT-C12 has a longer main chain (larger molecule weight) than PSDT-EH, which can favour a more extended main chain interaction. The vibronic peak at 519 nm and shoulder at 563 nm in the PSDT-C12 film further confirmed stronger main chain interaction. Geometry optimization showed that head–tail (HT)-PSDT had a more twisting conjugated backbone with larger dihedral angle between dithienosilole unit and thiadiazole-fused ring compared to head–head/tail–tail (HH/TT)-PSDT.     

Large-scale synthesis of nanocrystals of barium titanate and other titanates through solution-phase processes

We reported a large-scale synthesis of nanocrystals of BaTiO₃, SrTiO₃, PbTiO₃, Sr_xBa_1−xTiO₃ through low-temperature and solution-phase processes without any surfactant. The series of samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Samples obtained were of high purity, consisting of nanoparticles with fine crystallinity and uniformity as well as good dispersibility in ethanol. This method might also offer an effectively new way to synthesis other titanate nanocrystals with perovskite structure in the future.     

A new method for cross-calibration of two satellite sensors

Given that many operational satellite sensors are not calibrated, while a handful of research sensors are, cross-calibration between the two types of sensor is a cost-effective means of calibration. A new method of sensor cross-calibration is demonstrated here using the Chinese Multi-channel Visible Infrared Scanning radiometer (MVIRS) and the US Moderate Resolution Imaging Spectrometer (MODIS). MVIRS has six channels, equivalent to the current National Oceanic and Atmospheric Administration's (NOAA) Advanced Very High Resolution Radiometer (AVHRR) and four additional ones for remote sensing of ocean colour and moisture. The MVIRS on-board China's polar-orbiting meteorological satellite (FY-1D) was launched on 15 May 2002 with an earlier overpass time than Terra. The sensor has no on-board calibration assembly. This study attempts to calibrate MVIRS against the well-calibrated MODIS, by taking a series of measures to account for their differences. Clear-sky measurements made from the two sensors in July-October 2002 were first collocated. Using the 6S radiative transfer model, MODIS reflectances measured at the top-of-the atmosphere were converted into surface reflectances. They were corrected to the viewing geometry of the MVIRS using the bidirectional reflectance distribution function (BRDF) measured on the ground. The spectral response functions of the two sensors were employed to account for spectral discrepancies. After these corrections, very close linear correlations were found between radiances estimated from the MODIS and the digital readings from the MVIRS, from which the calibration gains were derived. The gains differ considerably from the pre-launch values and are subject to degradation over time. The calibration accuracy is estimated to be less than 5%, which is compatible to that obtained by the more expensive vicarious calibration approach.     

Studies on jet formation and penetration for a double-layer shaped charge

An analysis for liner collapsing and jet/slug formation of a double-layer shaped charge (DLSC) is presented. Variations of the collapse angle, collapse velocity, and jet velocity of the DLSC are discussed. Numerical simulations based on the Lee-Tarver model are performed to have an insight into the jet formation. Ballistic tests are conducted using a conical (60°) metal liner 56 mm in diameter to have a contrast with an ordinary shaped charge jet. It is shown that the collapse angle and velocity are both increased by the convergent detonation wave in the DLSC. The jet velocity, kinetic energy, and ballistic capability are significantly increased by using the DLSC, and the DLSC is an efficient way to improve shaped charge performance.     

On calorimetric study of the fragility in bulk metallic glasses with low glass transition temperature: (Ce0.72Cu0.28)90−x Al10Fex (x = 0, 5 or 10) and Zn38Mg12Ca32Yb18

Compared with conventional bulk metallic glasses, Ce-based and Zn-based bulk metallic glasses have received considerable attention because of their possible application as structural and functional materials. Kinetic fragility parameter m in amorphous material presents degree of deviations from the Arrhenius law above the glass transition temperature (T_g) of the material. Kinetic fragility parameter (m) and Kauzmann temperature (T_K) in (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10) and Zn₃₈Mg₁₂Ca₃₂Yb₁₈ bulk metallic glasses have been determined by differential scanning calorimetry (DSC). Results show that Zn₃₈Mg₁₂Ca₃₂Yb₁₈ presents a higher m than (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10). The activation energies E_g for glass transition are 1.51 eV (x = 0), 1.59 eV (x = 5) and 1.83 eV (x = 10) in (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10), and 3.59 eV in Zn₃₈Mg₁₂Ca₃₂Yb₁₈, respectively. The values of E_g increase with increasing the Fe content in (Ce_0.72Cu_0.28)_90?x Al₁₀Fe_x (x = 0, 5 or 10) bulk metallic glasses. Kinetic fragility parameter m of bulk metallic glasses increases with the glass transition temperature T_g of bulk metallic glasses, in agreement with previous investigations.     

Failure detection in automotive light assemblies during vibration endurance testing

As the automotive industry becomes increasingly competitive, parts manufacturers are under extreme pressure to improve the quality of their parts, while at the same time reducing costs. The method currently used to detect failures in automotive light assemblies during vibration endurance testing involves manual inspection only after the test is completed. In most cases, this method does not allow the first onset of failure to be determined. Subsequent damage caused by the ongoing test after the initial failure often obliterates the clues to what failed first, thus diminishing the usefulness of the information collected as input to design improvement iterations. An adaptable, reliable, and low-cost real-time monitoring and diagnostic system that would interrupt the testing operation at the first onset of a failure is desired. This paper describes an accelerometer-based and a microphone-based monitoring system for automotive light assembly failure detection during endurance testing. The vibration and acoustic signal analysis methods are also described. Preliminary results from these two systems show a significant difference between healthy and faulty fog light assemblies, which can be detected. This suggests that there is potential to develop these and potentially other measures for use in an adaptable, reliable, and low-cost real-time monitoring and diagnostic system that would interrupt the testing operation at the first onset of a failure. Further testing is planned to determine the sensitivity of the methods used in this study to detect the earliest onset of failure damage during endurance testing of automotive light assemblies.