United Nations International Conference on Space-based Technologies for Disaster Management Held in Beijing

The United Nations International Conference on Space-based Technologies for Disaster Management, "Risk Assessment in the Context of Global Climate Change", was held in Beijing during November 7-9, 2012. The conference was co-organized by the United Nations Office for Outer Space Affairs (UNOOSA) and the Ministry of Civil affairs (MCA) of the People's Republic of China, in collaboration with the Ministry of Foreign Affairs of PRC, China National Space Administration (CNSA),

Unleashing the Power of Information Theory: Enhancing Accuracy in Modeling Physical Phenomena

When building a model of a physical phenomenon or process, scientists face an inevitable compromise between the simplicity of the model (qualitative-quantitative set of variables) and its accuracy. For hundreds of years, the visual simplicity of a law testified to the genius and depth of the physical thinking of the scientist who proposed it. Currently, the desire for a deeper physical understanding of the surrounding world and newly discovered physical phenomena motivates researchers to increase the number of variables considered in a model. This direction leads to an increased probability of choosing an inaccurate or even erroneous model. This study describes a method for estimating the limit of measurement accuracy, taking into account the stage of model building in terms of storage, transmission, processing and use of information by the observer. This limit, due to the finite amount of information stored in the model, allows you to select the optimal number of variables for the best reproduction of the observed object and calculate the exact values of the threshold discrepancy between the model and the phenomenon under study in measurement theory. We consider two examples: measurement of the speed of sound and measurement of physical constants.

Electroluminescence of Si Nanocrystal-Doped SiO2

We perform a comparative st udy on the electroluminescence （EL） and photoluminescence （PL） of Si nanocrystaldoped SiO2 （nc-Si：SiO2） and SiO2, and clarify whether the contribution from Si nanocrystals in the EL of nc-Si：SiO2 truly exists. The results unambiguously indicate the presence of EL of Si nanocrystals. The difference of peak positions between the EL and PL spectra are discussed. It is found that the normal method of passivation to enhance the PL of Si nanocrystals is not equally effective for the EL, hence new methods need to be explored to promote the EL of Si nanocrystals.

Manipulating internal flow units toward favorable plasticity in Zr-based bulk-metallic glasses by hydrogenation

This work intends to manipulate the internal flow units in Zr_(55)Cu_(30)Ni_(5)Al_(10)bulk-metallic glasses(BMGs)through plasma-assisted hydrogenation to generate a positive microalloying effect on plasticity.Based on the cooperative shear model theory,serration-flow statistics during nanoindentation loading and creep tests during the holding stage were used to analyze the influence of hydrogen on the behavior of flow units in BMGs.Experimental observations showed that the hydrogen in the Zr_(55)Cu_(30)Ni_(5)Al_(10)BMGs caused mechanical softening,plasticity improvement,and structural relaxation.Analysis also showed that the average volume,size,and activation energy of internal flow units in the BMGs all increased as a result of the increase in the hydrogen content.The hydrogenation in the BMGs was found to lead to a prolifera-tion of shear bands,which promoted plasticity.The aggregation of these internal flow units reduced the stress required for plastic deformation through shear bands,ultimately causing softening and structural relaxation.

INTERNATIONAL SYSTEM OF UNITS(SI)

See ＂The International System of Units （SI）,＂ NIST Special Publication 330, B.N. Taylor, ed. （USGPO, Washington, DC, 1991）; and ＂Guide for the Use of the International System of Units （SI）,＂ NIST Special Publication 811, 1995 edition, B.N. Taylor （USGPO, Washington, DC, 1995）.

Exploring the Technical Assessment Standards for “Ordinary Purposes” in the CISG

Standards are the scientific basis and an important factor for the assessment of the quality of goods.In International Sale of Goods Law,they are consistent with and complementary to the“general provision”on“ordinary purposes”used to assess the quality of goods.Based on analyses of theories and legal practices and by reviewing the relationship between standards and“ordinary purposes,”in this article,I attempt to find out what standards affect the ascertaining of“ordinary purposes”and present a summary of the preconditions for the sellers’obligatory observance of such standards to provide guidance for the accurate application of other“general provisions”through the use of standards.