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1.
Seismic bearing capacity of shallow strip footings   总被引：6，自引：0，他引：6  
Seismic bearing capacity of shallow strip footings in soil has been obtained in the form of pseudo-static seismic bearing capacity factors Ncd, Nqd and Nd, denoting the cohesion, surcharge and unit weight components, respectively, by an extensive numerical iteration technique. Limit equilibrium method of analysis with composite failure surface is assumed. The validity of the principle of superposition is examined. Effects of both the horizontal and vertical seismic acceleration coefficients have been found to always reduce the ultimate bearing capacity significantly. Results obtained by the present method of analysis are compared with the available results and are found to be the least in the seismic case.  相似文献   

2.
Zusammenfassung 1Tc-Strontiohilgardit (Ca, Sr)2 [B5O8(OH)2,Cl] mit Ca : Sr etwa 1 : 1 ist ein neues Mineral der Hilgarditgruppe. Fundpunkt: Reyersbausen (9° 59,7 E, 51° 36,6 N), Grube Königshall-Hindenburg, Flöz Staßfurt in sylvinitischer Ausbildung.Konstanten : triklin-pedial,a 0=6,38 Å,b 0=6,480 Å,c 0=6,608 Å, =75,4°,=61,2°, =60,5°; tafelige-gestreckte Links- und Re chtskristalle, farblos, wasserunlöslich, piezoelektrisch. Härte 5–7, Dichte 2,99 g cm–3;n =1,638,n =1,639,n =1,670; 2V =19°.Neue Daten für die Hilgarditgruppe : 2 M (Cc)-Calciumhilgardit (=Hilgardit) =4 Ca2[B5O3(OH)2Cl], Raumgruppe Cc.3Tc-Calciumhilgardit (=Parahilgardit) = 3 Ca2[B5O3(OH)2Cl]; trinklin-pedial, 0=6,31 Å,b =6,484 Å,c 0=17,50 Å; =84,0°,=79,6°, =60,9°.Die Polymorphiebeziehungen sind geometrisch deutbar durch eine spezielle Art der Polytropie (Stapelung von Links- und Rechtskristallen im Elementarbereich).  相似文献   

3.
The axial base and skin capacities of piles bored in cohesion less soils are often estimated using empirical, semi-empirical and theoretical methods. The aim of this paper is to assess the applicability and evaluate the accuracy of different predictions methods available in the literature, via comparison with data from 43 field pile load tests conducted on shafts drilled in the region of the United Arab Emirates. Janbu's theoretical method (1989) with the parameter (=75°) and Vesics theoretical method (1975) yielded accurate predictions for the base resistances. Burlands approach (1973) overpredicts the skin capacities with an average predicted-to-estimated ratio (q p /q e) of three times greater than the unity while using values of the coefficient of earth pressure (k=05k o ) and the angle of soil-pile friction (=23).  相似文献   

4.
Summary The reflectance of oriented crystal faces parallel (100) and (001) of ilvaite was measured in air and in oil at different wavelengths with linearly polarized light. Refractive indices and absorption constants were calculated from the reflectance values. In contrast ton andn ,n has a strong dispersion. For the calculation ofn the absorption constant can be neglected. According to the unit cell ofBelov andMokeeva (1954) with the lattice constantsa 0=8.82,b 0=13.07,c 0=5.86 Å,n vibrates parallel to [001]n parallel to [100] andn parallel to [010]. Ilvaite is optically negative.
Auflichtuntersuchungen zur Optik des Ilvaits
Zusammenfassung Auf orientiert geschliffenen (100) und (001) Kristallplatten von Ilvait wurde das Reflexionsvermögen in Luft und in Öl mit linear polarisiertem Licht bei verschiedenen Wellenlängen gemessen. Aus den Reflexionswerten wurden die Brechungsindices und Absorptionskonstanten berechnet.n zeigt im Gegensatz zun undn eine auffallend starke Dispersion. Für die Berechnung vonn kann die Absorptionskonstante vernachlässigt werden. Nach der Aufstellung der Elementarzelle vonBelov undMokeeva (1954) mit den Gitterkonstantena 0=8,82,b 0=13,07,c 0=5,86 Å schwingtn parallel [001],n parallel [100] undn parallel [010]. Der Ilvait ist optisch negativ.

With 2 Figures  相似文献   

5.
Thermal treatments of anorthite carried out at up to 1,547° C show that the unit cell parameter changes as a function of the treatment temperature. The best fit curve found by non-linear least squares analysis is: =91.419-(0.327·10-6)T 2+(0.199·10-12)T 4-(0.391·10)T 6. The results obtained support significant Al,Si disorder (Al0.10, where Al=t 1(0)-1/3 [t 1(m)+t 2(0)+t 2(m)], Ribbe 1975), in anorthite equilibrated near the melting point and confirm a high temperature series differentiated from the low temperature series for calcic plagioclases in the An85–An100 range also. In the plot vs. An-content the high and low temperature curves intersect at An85 composition and progressively diverge in the An85–An100 range. The trends of the high and low temperature curves in this range are interpretable on the basis of the degree of Al, Si order in the average structures of calcic plagioclases.  相似文献   

6.
Mean and turbulent velocity measurements of supersonic mixing layers   总被引：1，自引：0，他引：1  
The behavior of supersonic mixing layers under three conditions has been examined by schlieren photography and laser Doppler velocimetry. In the schlieren photographs, some largescale, repetitive patterns were observed within the mixing layer; however, these structures do not appear to dominate the mixing layer character under the present flow conditions. It was found that higher levels of secondary freestream turbulence did not increase the peak turbulence intensity observed within the mixing layer, but slightly increased the growth rate. Higher levels of freestream turbulence also reduced the axial distance required for development of the mean velocity. At higher convective Mach numbers, the mixing layer growth rate was found to be smaller than that of an incompressible mixing layer at the same velocity and freestream density ratio. The increase in convective Mach number also caused a decrease in the turbulence intensity ( u /U).List of Symbols a speed of sound - b total mixing layer thickness betweenU 1 – 0.1U andU 2 + 0.1U - f normalized third moment ofu-velocity,f u 3/(U)3 - g normalized triple product ofu 2 v,g u 2 v/(U)3 - h normalized triple product ofu v 2, h uv' 2/(U)3 - l u axial distance for similarity in the mean velocity - l u axial distance for similarity in the turbulence intensity - M Mach number - M c convective Mach number (for 1=2),M c (U 1–U 2)/(a 1+a 2) - P static pressure - r freestream velocity ratio,rU 2/U 1 - Re unit Reynolds number,Re U/ - s freestream density ratio,s 2/ 1 - T t total temperature - u instantaneous streamwise velocity - u deviation ofu-velocity,u u–U - U local mean streamwise velocity - U 1 primary freestream velocity - U 2 secondary freestream velocity - U average of freestream velocities, ¯U (U 1 +U 2)/2 - U freestream velocity difference,U U 1 –U 2 - v instantaneous transverse velocity - v deviation ofv-velocity,v v – V - V local mean transverse velocity - x streamwise coordinate - y transverse coordinate - y 0 transverse location of the mixing layer centerline - ensemble average - ratio of specific heats - boundary layer thickness (y-location at 99.5% of free-stream velocity) - similarity coordinate, (y –y 0)/b - compressible boundary layer momentum thickness - viscosity - density - standard deviation - dimensionless velocity, (U –U 2)/U - 1 primary stream - 2 secondary stream A version of this paper was presented at the 11th Symposium on Turbulence, October 17–19, 1988, University of Missouri-Rolla  相似文献   

7.
Summary As suggested bySmith (1968) and supported by most structural data published since, in alkali feldspar the ** plot can be used for estimating (**), i. e. the difference in Al confent between 0 andm subsites. The present study investigates the topologically identical plot on the basis of the configuration of the alkali feldspar tetrahedral framework. Changes in Al content ofT-sites are functionally related to changes in cosines of and . While the total Al causing changes in cos is directly equal to the difference in Al content between 0 andm subsites, the total Al causing changes in cos is expressed by a complicated function which is equal with a very good approximation to three fourths of the difference in Al content betweenm and 0 subsites. This relation of quasiproportionality. like the feasible substitution in alkali feldspar of the diagram cos vs. cos by the plot, represents two simplifying assumptions which permit the difference in Al content to be calculated, as previously predicted.
Strukturelle Deutung für (**) aus dem */* der Alkalifeldspäte
Zusammenfassung Nach einem Vorschlag vonSmith (1968) und in Übereinstimmung mit den meisten seither publizierten Strukturdaten kann man in Alkalifeldspäten das */* zur Abschätzung von (**), also des Unterschiedes im Al-Gehalt auf der 0- undm-Position benützen. Die vorliegende Arbeit untersucht das topologisch idente /-Diagramm auf der Basis der Gestalt des Tetraederverbandes der Alkalifeldspäte. änderungen im Al-Gehalt derT-Position sind mit Änderungen im Kosinus von und korreliert. Während der die cos -änderungen verursachende Al-Gesamtgehalt unmittelbar dem Unterschied im Al-Gehalt derO-undm-Position entspricht, ist der die cos -Änderungen verursachende Al-Gesamtgehalt durch eine komplizierte Funktion ausgedrückt, die aber mit sehr guter Näherung drei Vierteln der Differenz im Al-Gehalt auf denm-und 0-Poisitionen entspricht. Diese quasi-Proportionalität und die Ersetzbarkeit des cos /cos -Diagrammes durch das /-Diagramm bei den Alkalifeldspäten stellen zwei Vereinfachungen bei der Berechnung des Al-Gehaltes dar.
  相似文献   

8.
Single crystals of boehmite, up to 0.1 mm in size, were found in open cavities inside a corundum crystal from the Ratnapura area gem gravels in Ceylon. The unit cell parameters are (X-ray powder pattern): a 0=3.695 Å b 0=12.212 Å, c 0=2.867 Å. The crystallographic orientation is based on X-ray single-crystal precession photographs. The crystals show the faces (it010), (001), (101), and (221). Systematic extinctions agree with the space group Amam. Optical orientation: a, b, c. Refractive indices are given. The mineral is optically positive with a large optic axial angle.  相似文献   

9.
Zusammenfassung Rooseveltit findet sich in der Oxidationszone der Lagerstätten San Francisco de los Andes und Cerro Negro de la Aguadita, in der Provinz San Juan, Argentinien, auf 30°22 S und 69°33 W. Er bildet sehr feinkörnige, weiß-graue, nach Bismuthinit pseudomorphe Aggregate. Die Brechungsindizes liegen zwischenn=2,10 und 2,30. Die Vickershärte beträgt 513 (4–5 der Mohs'schen Härteskala). Mittels Elektronenmikrosonde wurde folgende chemische Zusammensetzung bestimmt: As=21,5±1%, Bi=60,9±2%. Rooseveltit ist monoklin mita 0=6,878(1)Å, b0=7,163(1) Å, c0=6,735(1) Å, =104° 46±1, Z=4, calc.=6,94 g·cm–3, RaumgruppeP 21/n.Rooseveltit wurde nach drei verschiedenen Methoden synthetisiert. Die Pulverdiagramme der synthetischen Produkte stimmen mit dem des Minerals überein. Die Brechungsindizes wurden mitn =2,13(2) bzw. n=2,25(2) und die Dichte mit obs.=7,01 g·cm–3 bestimmt. Zellparameter: a0-6,882(1) Å, b0=7,164(1) Å, c0=6,734(1) Å, =104° 50,5±0,7, calc.=6,94 g·cm–3. Das synthetische Material schmilzt um 950°C. Selbst nach mehrstündigem Erhitzen auf 920°C läßt sich keine Veränderung im Pulverdiagramm des Minerals festellen.Es wird versucht, die natürliche Bildung des Rooseveltits zu erklären.
Rooseveltite from San Francisco de los Andes and Cerro Negro de la Aguadita, San Juan, Argentina
Summary Rooseveltite occurs in the weathering zone of the San Francisco de los Andes and Cerro Negro de la Aguadita mines, located in the San Juan Province, Argentina, at 30° 22S and 69° 33W. It appears in grey, finegrained aggregates pseudomorph after bismuthinite. Refraction index ranges fromn=2.10 to 2.30. The Vickers microhardness is 513 (4–5 of Mohs' scale). Chemical composition from electron micro probe measurements is As 21.5±1% and Bi 60.9±2%. Rooseveltite is monoclinic, with a0=6.878(1) Å, b0=7.163(1) Å, c0=6.735(1) Å, =104° 46±1, Z=4, calc.=6,94 g·cm–3, space groupP 21/n.The synthetic compound was prepared by three different methods. The powder pattern are the same as that of the mineral. Refraction index n=2.13(2) and n=2.25(2). The measured specific gravity is pobs.=7,01 g·cm–3. Cell parameters: a0=6.882(1) Å, b0=7.164(1) Å,c 0=6.734(1) Å, =104° 50.5±0.7, calc.=6,94 g·cm–3. The synthetic material melts at about 950°C. After heating to 920°C no variations were observed in the powder diagram of the mineral.It is tried to explain the formation of rooseveltite in natural environment.

Mit 2 Abbildungen  相似文献   

10.
In-situ synchrotron X-ray diffraction experiments were conducted using the SPEED-1500 multi-anvil press of SPring-8 on stishovite SiO2 and pressure-volume-temperature data were collected at up to 22.5 GPa and 1,073 K, which corresponds to the pressure conditions of the base of the mantle transition zone. The analysis of room-temperature data yielded V0=46.56(1) Å3, KT 0=296(5) GPa and K T =4.2(4), and these properties were consistent with the subsequent thermal equation of state (EOS) analyses. A fit of the present data to high-temperature Birch-Murnaghan EOS yielded (KT /T) P =–0.046(5) GPa K–1 and = a + bT with values of a =1.26(11)×10–5 K–1 and b =1.29(17)×10–8 K–2. A fit to the thermal pressure EOS gives 0=1.62(9)×10–5 K–1, ( K T / T) V =–0.027(4) GPa K–1 and (2P /T 2) V =27(5)×10–7 GPa K–2. The lattice dynamical approach by Mie-Grüneisen-Debye EOS yielded 0=1.33(6), q =6.1(8) and 0=1160(120) K. The strong volume dependence of the thermal pressure of stishovite was revealed by the analysis of present data, which was not detectable by the previous high-temperature data at lower pressures, and this yields ( K T / T) V 0 and q 1. The analyses for the fictive volume for a and c axes show that relative stiffness of c axis to a axis is similar both on compression and thermal expansion. Present EOS enables the accurate estimate of density of SiO2 in the deep mantle conditions.  相似文献   

11.
Because multidimensional ARMA processes have great potential for the simulation of geological parameters such as aquifer permeability, it was important to resolve which of two proposed alternative methods should be used for determining the two-dimensional weighting parameter, , for a unilateral ARMA (1, 0) process on a square net. Practical simulations demonstrates that the correct formulation is: =10/(1+ 10 2 where r,s is the correlation between lattice points at lagsr and s. When the simulations are performed with correlations of 0.8 or more a residual bias was detected which was found to be caused by a difference in the variance between the one- and two-dimensional models. This can be rectified by modifying the two- dimensional model as follows: zij=(zi–1, j + zi, j–1) + aij where 2=1/(1 + 10 2 ).  相似文献   

12.
In this experimental work I studied the correlation of the specific gravity and index of refraction at 19 moldavites from a finding place in Nchov. This place is in the south of Bohemia, in a district of eské Budjovice (Budweis). The reason for this work was the extraordinary declaration of the correlation of the specific gravity and index of refraction at one moldavite from Nchov that is: d=2,395 and n D =1,5033.These declarations were settled by Nováek. The results of these measurings have shown that the linear correlation of the specific gravity and index of refraction of the moldavites from other finding places are characteristic also for these ones. The definition of this correlation at 19 pieces of moldavites from Nchov shows also this linear character in the measuring of values d=2,355–2,395 and n D =1,4870–1,4950.In this work there were settled also some other dates of unity (so-called in couple-moldavites). But we must not oversee certain vaccilations of the declaration at the moldavites from Nchov, as at those from other finding places. The secularity of these declarations about the moldavites of Nchov lies also therein, that the avarage value of the correlation of specific gravity and index of refraction of this finding place is higher than those of other places.

Herrn Dr. Walter Weiskirchner, Dozent an der Universität Tübingen, danke ich herzlich für die freundliche Durchsicht der Arbeit.  相似文献   

13.
Summary Barylite has been identified for the first time in Greenland in several specimens from the nepheline syenite pegmatite pockets at Narssârssuk. The crystals are orthorhombic, showing the forms {100}, {210} and {201}, and form thin plates parallel to {100}. Electron microprobe analysis and emission spectrography show a composition close to the ideal formula. The refined unit cell paramters are:a=9.835(2) Å,b=11.654(3) Å andc=4.673(1) Å. The barylite is biaxial negative, 2V =66o±2o,n =1.694,n = 1.697 andn calc.=1.698.
Das erste grönländische Vorkommen des seltenen Minerales Barylith
Zusammenfassung Der seltene Barylith wurde zum ersten Mal in Grönland in verschiedenen Proben aus Nephelin-Syenit-Pegmatit-Drusen bei Narssârssuk identifiziert. Die Kristalle sind orthorhombisch mit den Formen {100}, {210} und {201}, sie bilden dünne Tafeln nach {100}. Elektronensonden-Analyse und Emissions-Spektrographie ergeben eine chemische Zussammensetzung, die der Idealform nahekommt. Die verfeinerten Zellparameter sind folgende:a=9,835(2) Å,b=11,654(3) Å undc=4,673(1) Å. Barylith ist zweiachsig negativ, 2V =66o±2o,n =1,694,n =1.697 undn calc.= 1,698.
  相似文献   

14.
Zusammenfassung Die chemische Analyse des neuen Minerals Johillerit mit der Elektronenmikrosonde ergab: Na2O 5,4, MgO 18,3, ZnO 5,4, CuO 15,8 und As2O5 55,8, Summe 100.7%. Aus diesem Ergebnis wurde die idealisierte Formel Na(Mg, Zn)3 Cu(AsO4)3 abgeleitet. Johillerit ist monoklin mit der RaumgruppeC2/c. Die Gitterkonstanten sind:a=11,870 (3),b=12,755 (3),c=6,770 (2) , =113,42 (2)°,Z=4. Die stärksten Linien des Pulverdiagramms sind: 4,06 (5) (22 ), 3,50 (4) (310), 3,25 (8) (11 ), 2,75 (10) (330, 240), 2,64 (5) (311, 13 , 40 ), 1,952 (4) (13 , 35 ), 1,682 (4) (20 , 460), 1,660 (5) (40 , 71 , 550, 64 ), 1,522 (4) (442, 153, 13 ). Es bestehen enge strukturelle Beziehungen zwischen Johillerit und O'Danielit, Na(Zn, Mg)3H2(AsO4)3, sowie einigen synthetischen. Verbindungen.Johillerit ist violett durchscheinend. Die Spaltbarkeit nach {010} ist ausgezeichnet und nach {100} und {001} gut.H (Mohs)3.D=4,15 undD X =4,21 g·cm–3. Das Mineral ist optisch zweiachsig positiv, 2V80 (5)°. Die Werte der Lichtbrechung sindn =1,715 (4),n =1,743 (4) undn =1,783 (4). Die Auslöschung istn b und auf (010)n c16°. Johillerit ist stark pleochroitisch mit den AchsenfarbenX=violett-rot,Y = blauviolett undZ = grünblau. Das neue Mineral kommt in radialstrahligen Massen gemeinsam mit kupferhaltigem Adamin und Konichalcit in zersetzem Kupfererz von Tsumeb, Namibia, vor. Die Benennung erfolgte nach Prof. Dr.J.-E. Hiller (1911–1972).
Johillerite, Na(Mg, Zn) 3 Cu(AsO 4 ) 3 , a new mineral from Tsumeb, Namibia
Summary Electron microprobe analysis of the new mineral johillerite gave Na2O 5.4, MgO 18.3, ZnO 5.4, CuO 15.8, and As2O5 55.8, total 100.7%. From this result, the ideal formula is given as Na(Mg, Zn)3 Cu(AsO4)3. Johillerite crystallizes monoclinic,C2/c. The unit cell dimensions are:a=11.870(3),b=12.755 (3),c=6.770 (2) , =113.42 (2)°,Z=4. The strongest lines on the X-ray powder diffraction pattern are: 4,06 (5) (22 ), 3,50 (4) (310), 3,25 (8) (11 ), 2,75 (10) (330, 240), 2,64 (5) (311, 13 , 40 ), 1,952 (4) (13 , 35 ), 1,682 (4) (20 , 460), 1,660 (5) (40 , 71 , 550, 64 ), 1,522 (4) (442, 153, 13 ). There is a close relationship between johillerite, o'danielite, Na(Zn, Mg)3H2(AsO4)3, and some synthetic compounds. Johillerite is violet in colour, transparent. Cleavage is {010} perfect, {100} and {001} good.H (Mohs)3.D=4.15 andD X =4.21 g·cm–3. The mineral is optically biaxial positive, 2V80 (5)°. The refractive indices are:n =1.715 (4),n =1.743 (4),n =1.783 (4). The extinction isn b and on (010)n c16°. Strongly pleochroic with axial coloursX=violet-red,Y=bluish violet andZ=greenish blue. The new mineral was found in radiated masses together with cuprian adamite and conichalcite in an oxidized copper ore from Tsumeb, Namibia. It is named in honour of Prof. Dr.J.-E. Hiller (1911–1972).

Mit 1 Abbildung  相似文献   

15.
Partition of Fe2+ and Mg between coexisting (Mg, Fe)2SiO4 spinel and (Mg, Fe)SiO3 pyroxene was investigated at pressures 80 and 90 kbar and at temperatures 840 and 1050° C, using tetrahedral-anvil type of high pressure apparatus. Olivine-spinel solid solution equilibria in the system Mg2SiO4-Fe2SiO4 were discussed in the light of the partition reaction. Partition of Fe2+ and Mg in both olivine-spinel and pyroxene-spinel systems can not be regarded as that between ideal solid solutions. By applying the simple solution model for the partition of Fe2+ and Mg, sign of the heat of mixing was estimated to be positive for all olivine, spinel and pyroxene. Relative concentration of Fe2+ in spinel in the pyroxene-spinel system is likely to cause some change in the chemical composition of modified spinel () or spinel () in the transition zone of the mantle. A considerable change is also expected in the transition pressure of to ( + ) and ( + ) to .Presented at the symposium Recent Advances in the Studies of Rocks and Minerals at High Pressures and Temperatures held in Montreal, 1972. Jointly sponsored by the International Mineralogical Association and the Commission on Experimental Petrology.  相似文献   

16.
Summary The crystal structure of a schröckingerite from Joachimsthal, NaCa3[UO2(CO3)3](SO4) F·10H2O, triclinic, space groupP1,a=9.634(1),b=9.635(1),c=14.391(2) Å, -91.41(1), =92.33(1), =120.26(1)°,V=1151 Å3,Z=2, has been determined by X-ray diffraction and refined toR=0.026 for 5451 reflections. The structure contains NaCa3[UO2(CO3)3] (SO4) F·6H2O layers built up from UO2(CO3) 3 4– anions, NaO3(H2O)3 octahedra, three kinds of CaO5F(H2O)2 polyhedra, Ca3F pyramids and Ca-bonded SO4 tetrahedra. These layers extend atz1/5 andz4/5 parallel to (001). They are linked parallel to c exclusively by hydrogen bonds, both directly as well as via interlayer H2O molecules. The structure shows a striking trigonal pseudosymmetry within the range 0.04<z<0.96. Atz0 these parts of the structure are dislocated relative to each other by a step of 1 Å parallel to [110]. Morphologic and optical properties of schröckingerite have been investigated in the light of the known crystal structure.
Kristallstruktur und kristallographische Eigenschaften eines Schröckingerits von Joachimsthal
Zusammenfassung Die Kristallstruktur eines Schröckingerits von Joachimsthal, NaCa3[UO2(CO3)3](SO4) F·10H2O, triklin, RaumgruppeP1,a=9,634(1),b=9,635(1),c=14,391(2) Å, =91,41(1), =92,33(1), =120,26(1)°,V=1151 Å3,Z=2, wurde mit Röntgenbeugung bestimmt und für 5451 Reflexe aufR=0.026 verfeinert. Die Kristallstruktur enthält NaCa3[UO2(CO3)3] (SO4)I·6H2O Schichten, die aus UO2(CO3) 3 4– . Anionen, NaO3(H2O)3-Oktaedern, drei Arten von CaO5F(H2O)2-Polyedern, Ca3 F-Pyramiden und an Ca gebundenen SO4-Tetraedern aufgebaut sind. Diese Schichten erstrecken sich inz1/5 undz4/5 parallel zu (001). Sie sind parallel zuc ausschließlich durch Wasserstoffbrücken verknüpft, und zwar sowohl direkt als auch indirekt durch zwischen den Schichten gelegene Wassermoleküle. Die Struktur zeigt im Bereich 0,04<z<0,96 eine ausgeprägte trigonale Pseudosymmetrie. Derartige Bereiche sind inz0 um etwa 1 Å parallel zu [110] stufenartig gegeneinander versetzt. Morphologische und optische Eigenschaften von Schröckingerit wurden im Licht der bekannten Kristallstruktur untersucht.

With 6 Figures  相似文献   

17.
Comparison between two types of multifractal modeling   总被引：1，自引：0，他引：1  
The interrelationships between two previously developed multifractal models are discussed. These are the Evertsz-Mandelbrot model developed on the basis of the multifractal spectrum f(), and the Schertzer-Lovejoy model based on the codimension function C() where and represent Hölder exponent and field order, respectively. It is shown how these two models are interrelated: they are identical for values of within the range D–(0)D–min. where D is the Euclidean dimension. For D–maxD–(0), however, f() remains a continuous function of whereas C() assumes constant value. In this respect, the fractal spectrum f() can provide more information about the multifractal measure than the codimension function C(). The properties of the two models are illustrated by application to the binomial multiplicative cascade model.  相似文献   

18.
Zusammenfassung Strontioginorit (Sr, Ca)2B14O23 8 H2O mit Sr: Ca1,3:0,7 tritt in gut ausgebildeten Kristallen im Alteren Steinsalz von Reyershausen bei Göttingen auf. Es ergaben sich folgende Daten : 0 = 12,850 Å,b 0 = 14,48 Å,c 0, = 12,855, Å, = 101° 35, RaumgruppeP 2I/a,Z = 4, Dichte=2,25 gcm–3,n = 1,512,n /b = 1,524,n //[101] = 1,577.  相似文献   

19.
Accelerating creep of the slopes of a coal mine   总被引：1，自引：0，他引：1  
A 249 day long record of the accelerating creep of a slope of an open-pit coal mine is analyzed, using linear regression, to test four creep laws. The Saito and Zavodni and Broadbent laws did not lead to a satisfactory estimation of the time of failure as a range of times of failure satisfied the goodness of fit criteria. Using the generalized Saito law, the upper limit for the time of failure was 168 days after the actual failure. Our prediction of a critical slide velocity for the evacuation of pit personnel and equipment, as an indication of impending failure, used two new methods employing the power and exponential laws. Three accelerating creep stages were identified, threshold velocities of 0.02 mm/min and 0.1 mm/min marked the initiation of the second and third stages, respectively.List of Symbols t time - t f relative time of failure - strain or displacement - 0 displacement at time zero, a constant - displacement rate - 1 at 1 minute - m at the mid point in the second acceleration stage - 0 at the onset of failure - f at failure - C, K, a, b, k, n, s Constants - I humber of measurements  相似文献   

20.
Estimation of mean trace length of discontinuities   总被引：18，自引：0，他引：18  
Summary Trace lengths of discontinuities observed on finite exposures are biased due to sampling errors. These errors should be corrected in estimating mean trace length. A technique, which takes into account the sampling errors, is proposed for estimating the mean trace length on infinite, vertical sections from the observations made on finite, rectangular, vertical exposures. The method is applicable to discontinuities whose orientation is described by a probability distribution function. The method requires that the numbers of discontinuities with both ends observed, one end observed, and both ends censored be known. The lengths of observed traces and the density function of trace length are not required. The derivation assumes that midpoints of traces are uniformly distributed in the vertical plane. Also independence between trace length and orientation is assumed. Data on a Pennsylvania shale in Ohio, U. S. A., were used as an example.Notations dip direction - direction of sampling plane - acute angle between dip direction and sampling plane - dip angle - A apparent dip angle - mean density of trace mid-points per unit area - mean trace length - D diameter of discontinuity - f (.),g (.) probability density function - h height of rectangular window - estimator of mean trace length - m sample size, number of discontinuities intersecting window - m 0 number of discontinuities intersecting window with both ends censored - m 2 number of discontinuities intersecting window with both ends observed - n, N expected number of discontinuities intersecting the window - n 0,N 0 expected number of discontinuities intersecting the window with both ends censored - n 2,N 2 expected number of discontinuities intersecting the window with both ends observed - Pr (.) probability - w width of rectangular window - x trace length  相似文献   

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