The upper ocean response to tropical cyclones in the northwestern Pacific analyzed with Argo data

A large number of autonomous profiling floats deployed in global oceans have provided abundant temperature and salinity profiles of the upper ocean. Many floats occasionally profile observations during the passage of tropical cyclones. These in-situ observations are valuable and useful in studying the ocean’s response to tropical cyclones, which are rarely observed due to harsh weather conditions. In this paper, the upper ocean response to the tropical cyclones in the northwestern Pacific during 2000–2005 is analyzed and discussed based on the data from Argo profiling floats. Results suggest that the passage of tropical cyclones caused the deepening of mixed layer depth (MLD), cooling of mixed layer temperature (MLT), and freshening of mixed layer salinity (MLS). The change in MLT is negatively correlated to wind speed. The cooling of the MLT extended for 50–150 km on the right side of the cyclone track. The change of MLS is almost symmetrical in distribution on both sides of the track, and the change of MLD is negatively correlated to pre-cyclone initial MLD.

Variation in the temperature field of rocks overlying a high-temperature cavity during underground coal gasification

High temperature affects rocks in a way that changes the physical and mechanical properties of them. The temperature field in rock overlying a high temperature zone has been estimated using experimental research on thermal conductivity of the overlying strata. Numerical analysis software was used to esti- mate rock thermal conductivity at different temperatures. These estimates were then used with COMSOL Multiphysics to perform a numerical analysis with the heat conduction model. The results show that rock thermal conductivity decreases as the temperature increases and that various lithologies show similar behavior. The thermal conductivity of each rock type differs from the others at a given temperature. Exact values for the temperature distribution in the overlying strata during the process of underground coal gasification are obtained from the numerical simulation. The temperature in the rock changes with the height and direction from the gasifier. Temperature gradients vary for different types of rock. This result provides an important reference for further study of the strength of overlying strata subject to the process of underground coal gasification.

Flavonoids from Euphorbia guyoniana Boissier ＆ Reuter

In this work, aerial parts of Euphorbia guyoniana were studied. The use of preparative high pressure liquid chromatography allowed to isolate two flavonoids and a gallic tannins： Quercetine-3 O-β-D-glucuronide, kaempferol-30-β-D-glucuronide and 1, 2, 6 tri-O-galloyl-β-D-glucose. Identifications were carried out using spectroscopic methods. In addition, scavenger potential of these compounds was studied using DPPH test.

Response of carrying capacity of piles induced by adjacent Metro tunneling

Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity of pile foundations provided by the impact of construction of urban tunnels on adjacent pile foundations, under the engineering background of the construction of the # 2 Line of the Guangzhou subway. It is carried out using a fast Lagrangian analysis of a continuum in a 3D numerical code, which is an elastoplastic three-dimensional finite difference model, to simulate the response of piles under the entire process of metro tunneling （deactivation of soil element and activation of the lining）. The adjacent stratum around the tunnel is classified into three regions： Zone Ⅰ （upper adjacent stratum of tunnel）, Zone Ⅱ （45°-upper-lateral adjacent stratum of tunnel） and Zone Ⅲ （lateral adjacent stratum of tunnel）. In each region one typical pile is chosen to be calculated and analyzed in detail. Numerical simulations are mainly conducted at three points of each pile shaft： the side-friction force of the pile, the tip resistance of the pile and the axial loading of the pile. A contrasting analysis has been conducted both in the response of typical piles in different regions and from computer calculated values with site monitoring values. The results of numerical simulations show that the impact on carrying capacity of the piles lies mainly in the impact of construction of urban tunnels on the side-friction forces and the tip resistance of piles. The impact differs considerably among the different strata zones where the pile tips are located. The complicated rules of side-friction force and tip resistance of piles has resulted in complicated rules of pile axial loading thus, in the end, it impacts the carrying capacity of pile-foundations. It is necessary to take positive measures, such as stratum grouting stabilization or foundation underpinning, etc, to deal with the carrying capacity and the settlement of pile-foundations. The results are of value to similar engineering projects.

MSG-3系统失效影响分析原理

民用飞机维修计划通常是依据MSG-3分析方法制定的,MSG-3分析包含结构、系统及动力装置、区域、L/HIRF四大类,其中系统MSG-3分析方法包括功能失效、失效影响及失效原因分析。国际规范MSG-32009.1给出了分析的通用流程,本文依据该分析流程,着重针对分析流程中的上层分析——失效影响分析,结合样例阐述了实际工程应用中应考虑的细节问题,使分析更合理有效。

Response of magnetic fields at geosynchronous orbit and on the ground to the sudden changes of IMF B_Z

The rapid change in the Earth’s magnetosphere caused by solar wind disturbances has been an important part of the solar wind-magnetosphere interaction.However most of the previous studies focused on the perturbation of the Earth’s magnetic field caused by solar wind dynamic pressure changes.In this paper,we studied the response of geosynchronous magnetic field and the magnetic field to the rapid southward turning of interplanetary magnetic field during the interval 1350 1420 UT on 7May 2007.During this event,BZ component of the interplanetary magnetic field decreased from 15 nT to 10 nT within 3 min(1403 1406 UT).The geosynchronous magnetic field measured by three geosynchronous satellites(GOES 10 12)first increased and then decreased.The variations of magnetic field strength in the morning sector(9 10 LT)were much larger than those in the dawn sector(5 LT).Meanwhile,the H components of geomagnetic field on the ground have similar response features but exhibit latitude and LT dependent variations.Compared with H components,the D components do not have regular variations.Although the solar wind dynamical pressure encounters small variations,the magnetic field both in space and on the ground does not display similar variations.Therefore,the increase of geomagnetic field in the dawn sector is caused by the southward turning of IMF(interplanetary magnetic field)BZ.These results will help to better understand the coupling process of geomagnetic filed and interplanetary magnetic field.