Observations with a mid-infrared camera of AGB star envelopes     

M. Marengo  M. Busso  L. Origlia  P. Persi  M. Ferrari-Toniolo  G. Silvestro  M. Tapia 《Astrophysics and Space Science》1995,224(1-2):511-512

We observed 17 AGB and post-AGB circumstellar envelopes wuth the midinfrared camera TIRCAM. The collected photometry is compared with the IRAS LRS spectra and a two color diagram for the chemical classification of the dust is developed.  相似文献   

Transport and Concentration of Gold in Metamorphic—hosted Reworked Gold Deposits,China     

Shengyuan Wang  Xiuzhang Wang  Jingping Cheng  Nan Wang 《中国地球化学学报》1993,12(1):60-70

Calculations based on the available thermodynamic data of AuCl ₂ ⁻ and Au (HS) ₂ ⁻ indicate that AuCl ₂ ⁻ is responsible for the transport and enrichment of gold during the stage of pre-concentration in the source bed while Au (HS) ₂ ⁻ is the main gold species involved in the formation of gold deposits in response to hydrothermal reworking. Acid chloride solutions witha _Cl ⁻ > 10° and sulfur-rich solutions with a_Σs in excess of 10⁻² are held as important criteria for gold enrichment in the source bed and for the formation of gold deposits by subsequent hydrothermal event, respectively.  相似文献   

层间储液的双层圆柱壳水弹性振动   总被引：1，自引：0，他引：1  

杨乃山  曲乃泗 《地震工程与工程振动》1995,15(2):75-83

本文对层间储有液体的双层圆柱层壳水弹性振动进行了详细的分析，重点研究了计算了双层圆柱厚壳考虑的剪切影响的刚度阵、质量阵及其水弹性动力特性，经出动水压力分布规律和任意动载荷下的动位移响应。文后附有算例，证明了本文方法的正确性和合理性。  相似文献   

内蒙古大青山地区早前寒武纪再造岩系及再造作用     

何政伟 《矿物岩石》1995,15(3):24-31

在内蒙古大青山地区存在再造太古宙基底，它经历了太古宙麻粒岩相变质作用和早元古宙角闪岩相－麻粒岩相的再造作用，再造太古宙基底岩石即为再造岩系，它是一套混合岩化变晶糜棱岩。再造岩系中混合岩化作用与再造作用同时，亦受韧性剪切变形变质作用控制。  相似文献   

Formation and photodestruction of pahs     

T. Allain  E. Sedlmayr  S. Leach 《Astrophysics and Space Science》1995,224(1-2):417-418

Photodissociation processes of PAHs are studied in the interstellar medium (ISM) and in the envelopes of carbon-rich C-stars.  相似文献   

A fossil record of shell boring: Possible evidence for sea level changes in the Red Sea     

Ehud Spanier   《Estuarine, Coastal and Shelf Science》1987,24(6)

An aggregation of fossil shells of the Indo-Pacific muricid snails Chicoreus ramosus was found in the northern part of the island of Tiran, Red Sea. The site was 7 m above the present mean sea level. Radiocarbon dating of these shells indicated an age of 1570±80 years BP. Some of these shells bore-drilled holes, most of them uncompleted. Biological study revealed that such holes were probably drilled by conspecifics in the absence of alternative food after they had been disconnected from the sea. Since there is no evidence of human activity in this part of Tiran, I suggest that such conditions could be caused only by a physical process that changed the relative water level. In accordance with the character of the drilled holes and the short period which muricids maintain reproductive aggregates, I also postulate that such a physical process must have been a relatively rapid one.  相似文献   

Metal and transuranic records in mussel shells, byssal threads and tissues     

Minoru Koide  Dong Soo Lee  Edward D. Goldberg 《Estuarine, Coastal and Shelf Science》1982,15(6)

Bivalve shells offer several advantages over tissues for the monitoring of heavy metal pollutants in the marine environment. They are easier to handle and to store. The problem of whether to depurate the animals before analyses is avoided. The shells appear to be more sensitive to environmental heavy metals levels over the long term than do the soft parts. Of the substances examined (Cd, Cu, Zn, Pb, Ag, Ni, ²³⁸Pu and ^{239 + 240}Pu) only Pb and Pu displayed a strong covariance between soft tissue and shell concentrations. There were strong correlations between metals in the shell but not in the soft tissues in general. The byssal threads, because of their enrichment of transuranic elements and of their ease in handling, may be useful in monitoring these metals. A very weak discharge of ²³⁸Pu to marine waters adjacent to a nuclear reactor was detected in the byssal threads of mussels.  相似文献   

The Influence of Residual Stress on Plastic Buckling of Cylindrical Shells     

Wu Lianyuan Hu Gangyi Professor  Shanghai Jiaotong University  Shanghai Engineer  Wuhan Ship Development & Design Institute  Wuhan 《中国海洋工程》1994,(2)

-This paper adopts approximate formulas for residual stresses caused by cold bending for plates with stress-strain curve form a = K n. A typical distribution of the longitudinal residual stress due to welding is also assumed. The effects of residual stress due to cold bending and welding on plastic buckling of axially compressed cylindrical shells are studied by the finite element method.  相似文献   

Optimal topology design of replaceable bar dampers of a reticulated shell based on sensitivity analysis     

Yang Yang  Ma Hui 《地震工程与工程振动(英文版)》2014,13(1):113-124

In this study,a method for control of reticulated shells is proposed and its practicality is demonstrated.The control is implemented by replacing selected bars of the shell with passive viscoelastic dampers.By applying the eigenvalue perturbation technique and the earthquake spectrum concept,the sensitivities of various topologies of the shell are analyzed,and the optimal topology is determined by taking their symmetries into consideration.The results of this research show that common damper topologies are not effective for all types of responses and recorded earthquakes.The optimal topology identifi ed requires a minimal number of dampers for each type of earthquake record.The displacement control effect of the dynamic responses of the optimal topology is 10% – 20%; the acceleration control effect is also about 10% – 20%; and the axial force control effect is as much as 30% – 45%.Furthermore,the incremental dynamic analysis(IDA) method is used to investigate the stability of the controlled shell.The results show that the dynamic stability of the controlled shell is well preserved when it is vibrated under vibration and is better than the uncontrolled shell.The ultimate load increased by 10% and the elements entered into the plastic stage when the peak acceleration reached 580 Gal,which is 200 Gal larger than the uncontrolled shell.  相似文献   

山东地区人工防雹用弹量的估算   总被引：1，自引：1，他引：0  

陈文选 《气象》2000,26(9):36-38

利用常规探空资料计算各地特征高度,采用７１１雷达雹云观测资料估算雹云中雹源含水量,从而得出每个作业点一次防雹作业用弹量的近似计算公式,并将计算结果与实际作业情况进行了对比。该方法可适用于山东地区人工防雹作业中用弹量的估算。  相似文献