Experimental Study of the Interaction between Building Clusters and Flash Floods

In recent years, flash flood disasters have occurred frequently in southwest China due to the increased frequency of extreme climate events. To solve this problem, great efforts have been made in studying the process of flash flood. However, little attention was paid on bearing body of hazard, the clusters of buildings. Thus the real disaster mechanism of flash flood remains unclear.Accordingly, based on the experiments of artificial flash floods in a conceptual solid model, this paper focuses on the flood-impacted inundation characteristics of the building clusters at different locations of the gully model, in order to obtain a better understanding of the disaster process and the interaction between the flash floods and building clusters. The results showed that, in a typical smallscale flash flood gully with hot and dry climate, 1)clusters of buildings on an alluvial fan could reduce about 35% of the flooding area by blocking the diffusion of the flood to the depression areas, and could also promote the deposition in lower reaches of the river channel by blocking the overbank flow from going back into the channel, making the width-depth ratio of the channel larger. 2) The flash flood rates of disaster and hazard on the alluvial fan are generally higher than that of the inner gully. For the inner gully,buildings located on the beaches along the lower river and the transitional areas of the straight channel and channel bends can easily be affected because of their lower elevations. For the alluvial fan, buildings nearby the meanders suffer the greatest impacts because of bank collapsing and flooding. 3) The safe vertical distance from a building to the river channel is 13 m for the buildings in the inner gully under extreme floods. Below this threshold, the smaller the vertical distance is, the greater the risk exposure is. For the buildings on the alluvial fan, especially for the buildings near the concave bank of the top rush point,the horizontal distance is more important, and the safe value is 80 m under extreme floods.

Seismic Theory of Tides; Theory of Forced Seismic Waves

Proceeding from the statement about presence of the normal resilient medium in the cosmic space, the author concludes seismic nature of tides and a number of other aspects of this phenomenon. The analysis of contradiction of the theory of tsunami to empiric facts led the author to conclude that the tsunami are forced and not free waves, and that the key moment in their distribution is the seismic compression of water.

Philosophy of Science and Post-theoretical Life-World

Philosophy of science has arisen as alternative to epistemology, because scientific development wanted another kind of explanation than traditional epistemological one. The latter kind of explanation is theoretically loaded and based on latent ontological assumptions. Epistemology offers science a ＂road map＂ for researcher＇s thinking. Thus epistemology knows what science should be, and philosophy of science take science for granted--existing as an empirical fact. Philosophy of science had always been a reflective and critical discipline that didn＇t want any a-priory knowledge. The main distinction between these fields of knowledge is as follows： epistemology is theoretical and projective kind of knowledge whereas philosophy of science is a non-theoretical, or better, a ＂post-theoretical＂ discipline. All facts and statements arising from philosophy of science lie within the heterogeneous space, where there is continuous transit of pre-theoretical, theoretical and post-theoretical versions of knowledge. The inevitability of conservation and utilization of human thought products is recognized, which is supplemented by the need to study the impact of theoretical thinking upon social practices.

Analysis of QUENCH-ACM Experiments Using SCDAP/RELAP5

The QUENCH experimental programme at Karlsruhe under severe accident conditions, but while the geometry is still Institute of Technology investigates heat-up and reflooding of a core mainly rod-like. The recent QUENCH-ACM series of experiments, comprising QUENCH-12 （El 10 cladding alloy）, -14 （M5 alloy） and -15 （Zirlo^TM alloy）, together with QUENCH-06 （reference case, Zircaloy-4 alloy） addressed the effect of alternative cladding materials on oxidation and quenching under similar conditions. Superficial inspection of the experimental results reveals only minor differences in the thermal and oxidation response, except for the much larger hydrogen release during reflood in QUENCH-12. Post-test calculations were performed using a version of SCDAP/RELAP5/MOD3.2, modified to represent the QUENCH facility and to invoke alternative oxidation correlations. The calculations agreed rather well with experiments QUENCH-06, -14 and -15, but the significant hydrogen release during reflood in QUENCH-12 was not captured. Closer examination of the experimental results reveals further differences between QUENCH-12 which may be linked to breakaway oxidation of the E110 cladding. The analyses support the heuristic observation that there was no major difference between the influence of Zircaloy-4, M5 or ZirloTM, but the E-110 exhibited a contrasting behaviour with a consequent impact on the reflooding.

Severe accident risks from external events

This paper reviews the early development of design requirements for seismic events in USA early developing nuclear electric generating fleet. Notable safety studies,including WASH-1400,Sandia Siting Study and the NUREG1150 probabilistic risk study,are briefly reviewed in terms of their relevance to extreme accidents arising from seismic and other severe accident initiators. Specific characteristic about the nature of severe accidents in nuclear power plant (NPP) are reviewed along with present day state-of-art analysis methodologies (methods for estimation of leakages and consequences of releases (MELCOR) and MELCOR accident consequence code system (MACCS)) that are used to evaluate severe accidents and to optimize mitigative and protective actions against such accidents. It is the aim of this paper to make nuclear operating nations aware of the risks that accompany a much needed energy resource and to identify some of the tools,techniques and landmark safety studies that serve to make the technology safer and to maintain vigilance and adequate safety culture for the responsible management of this valuable but unforgiving technology.

初中物理实验教学中学生科学素质的培养

中学物理教学必须加强实验教学,充分发挥物理实验教学的功能和优势,使其真正成为物理教学中提高学生素质,培养高素质人才的重要领域。

Effect of Soil Drying Intensity During an Experimental Drying-Rewetting Event on Nutrient Transformation and Microbial Community Composition

Soil drying-rewetting(DRW) events affect nutrient transformation and microbial community composition; however, little is known about the influence of drying intensity during the DRW events. Therefore, we analyzed soil nutrient composition and microbial communities with exposure to various drying intensities during an experimental drying-rewetting event, using a silt loam from a grassland of northern China, where the semi-arid climate exposes soils to a wide range of moisture conditions, and grasslands account for over 40% of the nation's land area. We also conducted a sterilization experiment to examine the contribution of soil microbes to nutrient pulses. Soil drying-rewetting decreased carbon(C) mineralization by 9%–27%. Both monosaccharide and mineral nitrogen(N) contents increased with higher drying intensities(drying to ≤ 10% gravimetric water content), with the increases being 204% and 110% with the highest drying intensity(drying to 2% gravimetric water content), respectively, whereas labile phosphorus(P)only increased(by 105%) with the highest drying intensity. Moreover, levels of microbial biomass C and N and dissolved organic N decreased with increasing drying intensity and were correlated with increases in dissolved organic C and mineral N, respectively,whereas the increases in labile P were not consistent with reductions in microbial biomass P. The sterilization experiment results indicated that microbes were primarily responsible for the C and N pulses, whereas non-microbial factors were the main contributors to the labile P pulses. Phospholipid fatty acid analysis indicated that soil microbes were highly resistant to drying-rewetting events and that drought-resistant groups were probably responsible for nutrient transformation. Therefore, the present study demonstrated that moderate soil drying during drying-rewetting events could improve the mineralization of N, but not P, and that different mechanisms were responsible for the C, N, and P pulses observed during drying-rewetting events.

Anti-infective reconstituted bone xenograft used for primary bone grafting to repair contaminated defect in the radius in dogs

Objective: To investigate the effect of anti-infective reconstituted bone xenograft as a primary graft to repair a segmental with severe contamination. Methods: A canine model of contaminated defect of 1.5 cm in size in the radius was used, in which anti-infective reconstituted bone xenograft or reconstituted bone xenograft was implanted as a primary graft followed by internal fixation. The effectiveness of the two grafting materials in repairing a contaminated segmental defect was compared. Results: The animals which had received implant of anti-infective reconstituted bone xenograft should largely healed defects 6 months after operation while the defects implanted with reconstituted bone xenograft remained unrepaired with bone infection. Conclusions: Besides its strong osteoinductive and osteoconductive activity, anti-infective reconstituted bone xenograft is highly antibacterial and can be used as a primary graft to repair the severely contaminated segmental defect.

Single-trial ERP evidence for the three-stage scheme of facial expression processing

Using a rapid serial visual presentation paradigm, we previously showed that the average amplitudes of six event-related potential (ERP) components were affected by different categories of emotional faces. In the current study, we investigated the six discriminating components on a single-trial level to clarify whether the amplitude difference between experimental conditions results from a difference in the real variability of single-trial amplitudes or from latency jitter across trials. It is found that there were consistent amplitude differences in the single-trial P1, N170, VPP, N3, and P3 components, demonstrating that a substantial proportion of the average amplitude differences can be explained by the pure variability in amplitudes on a single-trial basis between experimental conditions. These single-trial results verified the three-stage scheme of facial expression processing beyond multitrial ERP averaging, and showed the three processing stages of "fear popup", "emotional/unemotional discrimination", and "complete separation" based on the single-trial ERP dynamics.

Spectral spatial coherence of high-power multi-chip LEDs

We investigate the spatial coherence of the light generated from high-power multi-chip red LEDs by usmg the van Cittert- Zernike theorem. It is theoretically demonstrated that the light generated from multi-chip LEDs evolves into partially coherent light after propagation, and the spatial coherence is increased with the increase of propagation distance. Moreover, the spatial coherence of the light is found to be closely related to the chip distribution of multi-chip LEDs. The distribution of the spatial coherence of the light is experimentally examined by Young＇s double-slit interference. It is found that the experimental results are consistent with the theoretical ones.