On the possibilities of studying impulsive elastic waves in an inhomogeneous medium by the finite difference method     

Jiří Zahradník  Reviewer J. Vaněk 《Studia Geophysica et Geodaetica》1974,18(4):339-358

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New orthorhombic phases on the join NiAl2O4 (spinel analog)-Ni2SiO4 (olivine analog): Stability and implications to mantle mineralogy     

Che-Bao Ma 《Contributions to Mineralogy and Petrology》1974,45(4):257-279

Three new crystalline phases differing in Si/Al ratio have been synthesized from compositions along the join NiAl₂O₄-Ni₂SiO₄. Four reversible univariant equilibria involving these new phases plus Ni₂SiO₄ (olivine) have been located within the P-T region studied (1 atm–40 kb, 1000–1700° C); an invariant point occurs near 22 kb, 1150°C.All three new phases are orthorhombic. Precession photographs and electron microprobe analyses yield the following information:Phase I: 5NiO·3Al₂O₃·SiO₂ = 3NiAl₂O₄·Ni₂SiO₄, Pmma, a=5.67, b=11.51, c=8.10 (Å)Phase II: 7NiO·3Al₂O₃·2SiO₂ = 3NiAl₂O₄· 2Ni₂SiO₄, Imma, a=5.66, b=17.32, c=8.11Phase III: 3NiO· Al₂O₃· SiO₂ = NiAl₂O₄·Ni₂SiO₄, Imma, a=5.68, b=11.49, c=8.12Comparison with known structures suggests that these three phases plus NiAl₂O₄ spinel and high pressure Ni₂SiO₄ spinel belong to a homologous series based on a cubic close oxygen packing of the formula: M_2n O _n}-1 (T _n O_3n+1) where M and T are octahedrally and tetrahedrally coordinated cations, respectively. When n=1 the formula for spinel is obtained; n = 2 for phase I and phase III, both similar to the beta-phase of orthosilicates; and n = 3 for phase II which is related to the manganostibite structure.Similar phase equilibria and structural relations may occur on other joins of the aluminateorthosilicate type. Furthermore, the occurrence of such structural modifications between the spinel (aluminate) and olivine (orthosilicate) compositions suggests that there could be a corresponding polymorphic series between the olivine and spinel forms of orthosilicates.  相似文献   

A thermo‐mechanical model for variably saturated soils based on hypoplasticity     

David Mašín  Nasser Khalili 《国际地质力学数值与分析法杂志》2012,36(12):1461-1485

The paper presents a mechanical model for non‐isothermal behaviour of unsaturated soils. The model is based on an incrementally non‐linear hypoplastic model for saturated clays and can therefore tackle the non‐linear behaviour of overconsolidated soils. A hypoplastic model for non‐isothermal behaviour of saturated soils was developed and combined with the existing hypoplastic model for unsaturated soils based on the effective stress principle. Features of the soil behaviour that are included into the model, and those that are not, are clearly distinguished. The number of model parameters is kept to a minimum, and they all have a clear physical interpretation, to facilitate the model usefulness for practical applications. The step‐by‐step procedure used for the parameter calibration is described. The model is finally evaluated using a comprehensive set of experimental data for the thermo‐mechanical behaviour of an unsaturated compacted silt. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

CHINA’S FOUR MAJOR METEOROLOGICAL SCIENTIFIC EXPERIMENTS     

Ma Henian  Tang Xu 《Acta Meteorologica Sinica》1999,13(2):129-140

China lies in East-Asian monsoon region,which is one of the well-known active monsoon zones around the world.Monsoon anomaly results in frequent natural disasters,such as drought,torrential rain and flood.In 1998,joint intensified observations for 4 major meteorological scientific experiments have been carried out over Chinese major monsoon affected areas.A number of valuable data have been obtained and some observational facts have come out after initial analysis.The present paper is to give an introduction to the 4 major meteorological scientific experiments conducted in 1998 in China.including its origin and scientific goals,implementation and planning,equipment and progress,and initial findings from the important observational facts.It aims to provide a comprehensive report on the progress of the above experiments for those who are interested in.  相似文献   

Application of Astronomic Time-latitude Residuals in Earthquake Prediction   总被引：1，自引：0，他引：1  

Han Yanben  Ma Lihua  Hu Hui  Wang Rui  Su Youjin 《Earth, Moon, and Planets》2007,100(1-2):125-135

After the earthquake (Ms = 6.1) occurred in Luquan county of Yunnan province on April 18, 1985, the relationship between major earthquakes and astronomical time-latitude residuals (ATLR) of a photoelectric astrolabe in Yunnan Observatory was analyzed. ATLR are the rest after deducting the effects of Earth’s whole motion from the observations of time and latitude. It was found that there appeared the anomalies of the ATLR before earthquakes which happened in and around Yunnan, a seismic active region. The reason of the anomalies is possibly from change of the plumb line due to the motion of the groundmass before earthquakes. Afterwards, using studies of the anomalous characters and laws of ATLR, we tried to provide the warning information prior to the occurrence of a few major earthquakes in the region. The significant synchronous anomalies of ATLR of the observatory appeared before the earthquake of magnitude 6.2 in Dayao county of Yunnan province, on July 21, 2003. It has been again verified that the anomalies possibly provide the prediction information for strong earthquakes around the observatory.  相似文献   

Book reviews     

Tlamicha  Antonín  Podolský  Jiří 《Astrophysics and Space Science》1986,120(2):307-308

Astrophysics and Space Science -  相似文献   

A Survey of Newtonian Core-Shell Systems with Pseudo High Order Symplectic Integrator and Fast Lyapunov Indicator     

Jun-Fang Zhu Xin Wu Da-Zhu Ma 《中国天文和天体物理学报》2007,7(4):601-610

Newtonian core-shell systems, as limiting cases of relativistic core-shell models under the two conditions of weak field and slow motion, could account for massive circumstellar dust shells and rings around certain types of star remnants. Because this kind of systems have Hamiltonians that can be split into a main part and a small perturbing part, a good choice of the numerical tool is the pseudo 8th order symplectic integrator of Laskar ＆ Robutel, and, to match the symplectic calculations, a good choice of chaos indicator is the fast Lyapunov indicator （FLI） with two nearby trajectories proposed by Wu, Huang ＆ Zhang. Numerical results show that the FLI is very powerful when describing not only the transition from regular motion to chaos but also the global structure of the phase space of the system.  相似文献   

Search for GRB related prompt optical emission and other fast varying objects with “Pi of the Sky” detector     

M. Ćwiok  W. Dominik  K. Małek  L. Mankiewicz  J. Mrowca-Ciułacz  K. Nawrocki  L. W. Piotrowski  P. Sitek  M. Sokołowski  G. Wrochna  A. F. Żarnecki 《Astrophysics and Space Science》2007,309(1-4):531-535

Experiment “Pi of the Sky” is designed to search for prompt optical emission from GRB sources. 32 CCD cameras covering 2 steradians will monitor the sky continuously. The data will be analysed on-line in search for optical flashes. The prototype with 2 cameras operated at Las Campanas (Chile) since 2004 has recognised several outbursts of flaring stars and has given limits for a few GRB.  相似文献   

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马开锋  彭碧波  洪樱 《大地测量与地球动力学》2007,27(1):85-90

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流气式正比计数管效率标定     

任基 《成都信息工程学院学报》1990,(1)

本文介绍了一种新的标定流气式正比计数管的方法。此方法的特点是把正比管作为吸收体,利用He气对光子较为透明的原理,标定正比管的探测效率。方法简便实用,并对P-10(90%Ar+10%CH_4)为工作气体的正比管进行了标定。  相似文献