Relationship between load/unload response ratio and damage variable and its application

The physics-based parameter: load/unload response ratio (LURR) was proposed to measure the proximity of a strong earthquake, which achieved good results in earthquake prediction. As LURR can be used to describe the damage degree of the focal media qualitatively, there must be a relationship between LURR and damage variable (D) which describes damaged materials quantitatively in damage mechanics. Hence, based on damage mechanics and LURR theory, taking Weibull distribution as the probability distribution function, the relationship between LURR and D is set up and analyzed. This relationship directs LURR applied in damage analysis of materials quantitatively from being qualitative earlier, which not only provides the LURR method with a more solid basis in physics, but may also give a new approach to the damage evaluation of big scale structures and prediction of engineering catastrophic failure. Copyright (c) 2009 John Wiley & Sons, Ltd.

Detection of avian influenza virus subtype H5 using a biosensor based on imaging ellipsometry

A novel method is reported for the detection of avian influenza virus subtype H5 using a biosensor based on high spatial resolution imaging ellipsometry (IE). Monoclonal antibodies specific to H5 hemagglutinin protein were immobilized on silicon wafers and used to capture virus particles. Resultant changes on the surface of the wafers were visualized directly in gray-scale on an imaging ellipsometry image. This preliminary study has shown that the assay is rapid and specific for the identification of avian influenza virus subtype H5. Compared with lateral-flow immunoassays, this biosensor not only has better sensitivity, but can also simultaneously perform multiplexed tests. These results suggest that this biosensor might be a valuable diagnostic toot for avian influenza virus detection. (c) 2009 Elsevier B.V. All rights reserved.

翻耙补播对科尔沁碱化草地土壤理化性质和生物活性的影响

对科尔沁地区碱化草甸草地翻耙补播沙打旺后的土壤理化性质和土壤生物活性的变化进行了研究。结果表明,翻耙补播改良后草地综合生产性能得到明显改善,土壤容重、pH、含盐量和碱化度降低,土壤含水量和孔隙度增加,土壤有机质和N、P、K等养分含量增加;同时,土壤微生物C、N的含量以及土壤酶的活性也得到较大幅度提高。

Stable isotopic compositions in Australian precipitation

Stable deuterium (delta D) and oxygen-18 (delta O-18) isotopes in 1962 to 2002 precipitation from the seven Australian stations of the Global Network of Isotopes in Precipitation (GNIP) were used to investigate isotope characteristics including temporal and spatial distributions across different regions of Australia. On the basis of 1534 samples, the local meteoric water line (LMWL) was established as delta D = 7.10 delta O-18 + 8.21. delta O-18 showed a depletion trend from north and south to central Australia (a continental effect) and from west to east. Precipitation amount effects were generally greater than temperature effects, with quadratic or logarithmic correlations describing delta/T and delta/P better than linear relationships. Nonlinear stepwise regression was used to determine the significant meteorological control factors for each station, explaining about 50% or more of the delta O-18 variations. Geographical control factors for delta O-18 were given by the relationship delta O-18 (parts per thousand) = -0.005 longitude (degrees) - 0.034 latitude (degrees)-0.003 altitude (m) - 4.753. Four different types of d-excess patterns demonstrated particular precipitation formation conditions for four major seasonal rainfall zones. Finally, wavelet coherence (WTC) between delta O-18 and SOI confirmed that the influence of ENSO decreased from east and north to west Australia.

二维分子形状和定量手性程度的研究

以二进制编码描述苯环型化合物分子在二维空间的形状,所得到的编码能够区分二维平面上一对苯环型化合物对映体。由于对映体的二进制编码不同,基于化合物和其镜像的编码计算得到了海明距离,并以其表征1对对映体的定量手性程度。以28对周长为22的手性苯环型化合物对映体为实例,计算苯环型化合物的定量手性程度,其结果仅仅有2个数值,分别为海明距离4和6。具有不同形状的该类化合物很多,为了提高分辨率,分别计算了窗口宽度从1～16时的海明距离,并分别以其来代表定量手性程度。结果显示全部16个窗口的海明距离的加和具有最大的区分能力,共得到17种海明距离。如果将每一窗口的细节引入到计算中,并采用类似的方法计算,则实例中所有的28个苯环型化合物实现了完全的区分,所得到的定量手性程度的区分能力是令人满意的。本研究证明如果用适当的编码来描述二维空间中分子的边界,能够解决分子形状的定量表征。尽管本文的二进制编码衍生于平...

海藻抗肿瘤抗细菌生物活性物质的研究

该文对近四年来海洋抗肿瘤药物的研究现状和大型海藻天然产物的研究现状进行了简要的综述.概述了近年来世界各国的海藻抗肿瘤筛选方面的工作进展;总结了近年来从蓝藻、甲藻、红藻、褐藻、绿藻中分离的活性化合物,其中包括已经进入临床研究阶段的Scytophycin、Halomon、Cryptophycin、Malyngamide、Tolytoxin等.综述了近四年来从大型海藻中分离的约100个天然化合物,其中大部分具有重要的生物活性.以采自山东沿海的39种海藻的96个样品为材料,进行了较系统的抗肿瘤生物活性的筛选,共发现了8种有选择性抗肿瘤活性的海藻.运用薄层层析方法对10种海藻提取物的抗金黄色葡萄球菌和大肠杆菌活性进行了研究,发现褐藻提取物的抗菌活性最高,红藻的抗菌活性较低,而绿藻门海藻几乎没有活性.红藻门的松节藻、鸭毛藻有一定的活性.褐藻门的酸藻和海黍子活性较高.酸藻和海黍子的3个强抗菌活性带对金黄色葡萄球菌的抑菌圈直径分别为33mm、17mm和17.5mm,酸藻水相的2个活性带还能抑制大肠杆菌,其抑菌圈直径分别为21mm和16mm.对山东沿海分布量较大的两种海藻进行了先导化合物的分离纯化和结构鉴定.对萱藻和松节藻中得到的纯化合物和其它粗提物进行了细胞毒活性的检验.

The behaviors and sources of dissolved arsenic and antimony in Bohai Bay

In this paper, we determined the concentrations of antimony species (antimonite (Sb(III)), antimonate (Sb(V)) and dissolved inorganic antimony (DISb)) and arsenic, in Bohai Bay seawaters, as well as the relationships of the analytes with environmental factors such as seawater characteristics (e.g., suspended particulate material (SPM), salinity and total organic carbon (TOC)), heavy metals, nutrients and phytoplankton species, and evaluated the sources of arsenic and antimony. Dissolved arsenic and antimony concentrations in the surface waters were ranging spatially from 1.03 to 1.26 ng/ml and 0.386 to 1.075 ng/ml, with mean values of 1.18 and 0.562 ng/ml, respectively. Sb(V) as the prominent chemical species constituted about 89%. Regarding arsenic concentrations in the surface waters, there was a tendency for a small variation. However, antimony species concentrations were much variable than arsenic. The highest arsenic and antimony concentrations were found near the Haihe Estuary. These distribution patterns were controlled mainly by environmental factors, biological activities and sources. In this region, DISb and Sb(V) negatively correlated with salinity. Besides, arsenic and antimony correlated well with the nutrients, chlorophyll a and phytoplankton, implying that arsenic and antimony had been involved in biological cycling. In addition, according to our estimate, about 333.5 x 10(8) mg/year of arsenic and 454.2 x 10(8) mg/year of antimony reached Bohai Bay via rivers. (C) 2010 Elsevier Ltd. All rights reserved.

印度与欧亚板块强烈相互作用区深部结构特征研究

The central-south Tibet is a part of the products of the continental plate collision between Eurasia and India. To study the deep structure of the study area is significant for understanding the dynamics of the continental-continental collision. A 3-D density model matched well with the observations in the central-south Tibet was proposed in this study. In addition, this study has also used numerical simulation method to prove that Quasi-Love (QL) wave is deduced by anisotropy variation but not by lateral heterogeneity. Meanwhile, anisotropy variation in the upper mantle of the Qiangtang terrane and Lhasa terrane is detected by the QL waves observed in recorded seismograms. Based on the gravity modeling, some results are summarized as follows: 1) Under the constrain of geometrical structure detected by seismic data, a 3-D density model and Moho interface are proposed by gravity inversion of the central-south Tibet. 2) The fact that the lower crustal densities are smaller than 3.2 g/cm3, suggests absence of eclogite or partial eclogitization due to delamination under the central-south Tibet. 3) Seismicity will be strong or weak in the most negative Bouguer gravity anomaly. So there is no a certain relationship between seismicity and Bouguer gravity anomaly. 4) Crustal composition are determined after temperature-pressure calibration of seismic P wave velocity. The composition of lower crust might be one or a mixture of: 1. amphibolite and greenschist facies basalt beneath the Qiangtang terrane; 2. gabbro-norite-troctolite and mafic granulite beneath the Lhasa terrane. Because the composition of the middle crust cannot be well constrained by the above data set, the data set published by Rudnick & Fountain (1995) is used for comparison. It indicated the composition of the middle crust is granulite facies and might be pelitic gneisses.Granulite facies used to be interpreted as residues of partial melting, which coincidences with the previous study on partial melting middle crust. Amphibolite facies are thought to be produced after delamination, when underplating works in the rebound of the lower crust and lithospheric mantle. From the seismology study, I have made several followed conclusions: 1) Through the numerical simulation experiment of surface wave propagating in heterogeneity media, we can find that amplitude and polarization of surface wave only change a little when considering heterogeneity. Furthermore, it is proved that QL waves, generated by surface wave scattering, are caused by lateral variation of anisotropy but not by heterogeneity. 2) QL waves are utilized to determine the variation of uppermost mantle anisotropy of the Tibetan plateau. QL waves are identified from the seismograms of the selected paths recorded by the CAD station. The location of azimuth anisotropy gradient is estimated from the group velocities of Rayleigh wave, Love wave and QL wave. It suggests that south-north lateral variation of azimuthal anisotropy locates in Tanggula mountain, and east-west lateral variation in the north of Gandese mountain with 85°E longitude and near the Jinsha river fault with 85°E longitude.