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  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Inorganic chemistry 34 (1995), S. 2870-2874 
    ISSN: 1520-510X
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 107 (1985), S. 1427-1429 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Pure and applied geophysics 129 (1989), S. 325-343 
    ISSN: 1420-9136
    Schlagwort(e): Source mechanism ; seismic moment tensor ; gas outburst ; Sunagawa Coal Mine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract On January 29ty, 1986, the third largest gas outburst in Japan took place at Sunagawa Coal Mine, which is the only hydraulic mine in Japan. It occurred at a face of a cross-cut, just after a coal seam was outcropped by blasting for drivage of the cross-cut. The site of the gas outburst was located 1,180 m below the surface. No workers were injured, but the cross-cut was plugged with 1,600 m3 of coal fragments extending over 100 m behind the face and 60,000 m3 of methane gas was emitted. The site of the gas outburst was investigated in detail to clarify the geological features. A normal and a reverse fault existed at the site. The area of the ejected zone was about 400 m2 and extended upward along the normal fault. The shape of the ejected zone suggests a great role of the normal fault on the gas outburst. Digital seismograms, recorded by a mine-wide seismic array at the coal mine, consisting of 27 microseismic events were used to investigate the gas outburst. Magnitude, seismic energy release, distribution of hypocenter and focal mechanism were analyzed. Taking the shape of the ejected zone together with results of the seismological investigation into consideration, it appears that the seismicity started with left-lateral faulting of the reverse fault and then right-lateral faulting of the normal fault followed. The faulting of the normal fault might be the direct cause and be the predominant mechanism of the gas outburst.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Pure and applied geophysics 152 (1998), S. 551-577 
    ISSN: 1420-9136
    Schlagwort(e): Key words: Failure criterion, circumferential strain, brittle rock, peak load, critical tensile strain, tensile strain criterion.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract —Uniaxial compression, triaxial compression and Brazialian tests were conducted on several kinds of rock, with particular attention directed to the principal tensile strain. In this paper we aim to clarify the effects of the experimental environment—such as confining pressure, loading rate, water content and anisotropy—on the critical tensile strain, i.e., the measured principal tensile strain at peak load.¶It was determined that the chain-type extensometer is a most suitable method for measuring the critical tensile strain in uniaxial compression tests. It is also shown that the paper-based strain gage, whose effective length is less than or equal to a tenth of the specimen’s diameter and glued on with a rubber-type adhesive, can be effectively used in the Brazilian tests.¶The effect of confining pressure P C on the critical tensile strain ɛ TC in the brittle failure region was between −0.02 × 10−10 Pa−1 and 0.77 × 10−10 Pa−1. This pressure sensitivity is small compared to the critical tensile strain values of around −0.5 × 10−2. The strain rate sensitivities ∂ɛ TC /∂{log(d|ɛ|/dt)} were observed in the same way as the strength constants in other failure criteria. They were found to be from −0.10 × 10−3 to −0.52 × 10−3 per order of magnitude in strain rate in the triaxial tests. The average magnitude of the critical tensile strain ɛ TC increased due to the presence of water by 4% to 20% for some rocks, and decreased by 22% for sandstone. It can at least be said that the critical tensile strain is less sensitive to water content than the uniaxial compressive strength under the experimental conditions reported here. An obvious anisotropy was observed in the P-wave velocity and in the uniaxial compressive strength of Pombetsu sandstone. It was not observed, however, in the critical tensile strain, although the data do show some variation.¶A "tensile strain criterion" was proposed, based on the above experimental results. This criterion signifies that stress begins to drop when the principal tensile strain reaches the critical tensile strain. The criterion is limited to use within the brittle failure region. The critical tensile strain contains an inelastic strain component as well as an elastic one. It is affected by the strain rate, however, it is relatively insensitive to the confining pressure, the presence of water and anisotropy.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Pure and applied geophysics 157 (2000), S. 2283-2301 
    ISSN: 1420-9136
    Schlagwort(e): Key Words: Scaling law, large earthquake, plate boundary, seismic zone, thermal structure.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract —We compiled 67 large earthquakes which occurred at and around plate boundaries for the last 140 yrs, and classified them into four groups; interplate strike-slip events, intraplate strike-slip events, underthrust events at island-arc subduction zones, and underthrust events at continental-margin subduction zones. For each group of earthquakes we examined relations between seismic moment M 0, fault length L, fault width W and average fault slip D, and found the following scaling laws. In the case of interplate strike-slip events, the well-known L-cubed dependence of seismic moment breaks down when L exceeds 30 km, because the extent of the seismogenic zone is limited in depth (≤12 km). For large events (L≥ 30 km), D and M 0 increase with L as $D=\overline {\rm \Delta \tau}L /\mu (\alpha L+\beta )$ and $M_{0}=\overline {\rm \Delta \tau W}L^{2} / (\alpha L+\beta)$ , respectively, where the mean fault width $\overline {W}$ is 12 km and the mean stress drop $\overline {\rm \Delta \tau}$ is 1.8 MPa. Here μ, α and β are structural parameters. For intraplate strike-slip events we obtained nearly the same relations, except for significantly higher stress drop (3.1 MPa). The difference in stress drop between interplate and intraplate events may be ascribed to the difference in stress accumulation rates and thus the recurrence time of earthquakes. In the case of underthrust events at island-arc subduction zones we also found the saturation of fault width ( $\overline {W}$ = 120 km) and the breakaway from the L-cubed dependence of M 0 for events larger than L = 200 km. If we consider the average dip-angle of plate boundaries at island-arc subduction zones to be 20–30°, this indicates that the extent of the seismogenic zone in depth is limited to 40–60 km. In the case of continental-margin subduction zones, on the other hand, we could not find the saturation of fault width nor the breakaway from the L-cubed dependence of M 0 from the analysis of the present data set (W≤ 200 km, L≤ 1000 km). For sufficiently large earthquakes, in general, the downward rupture growth is limited to a certain depth due to the existence of a ductile unstressed region which extends under the brittle seismogenic zone. Since the brittle-ductile transition occurs at 300–400°C, the difference in the lower limit of the seismogenic zones between tectonically different regions may be attributed to the difference in thermal state there.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Pure and applied geophysics 149 (1997), S. 115-127 
    ISSN: 1420-9136
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract It is widely acknowledged that the 1964 Niigata, Japan, earthquake is associated with the preseismic anomalous crustal movement detected by repetition of precise levelings, while some doubts have been raised on the validity of reported precursory movement. Validity of the crustal movement is tested by an analysis of tidal data. When we are able to deduce crustal movement referring to the determined mean sea level, we can discuss the absolute crustal movement. Tidal data along the Japan Sea coast of northeast Japan are analyzed by the method developed inTsumura (1963, 1970) for the period from 1955 to 1986. The final results at tidal station, Nezugaseki, indicate clearly the steady-state movement during 1955–1958, 4 cm of abnormal upheaval from 1959–1964, 20 cm of coseismic abrupt subsidence, and 4 cm of postseismic rapid subsidence, and finally very gradual subsidence. Thus the present results support the idea of the typical pattern of the seismic crustal movement, including the precursory movement.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0428
    Schlagwort(e): Quick-freezing ; deep-etching ; glomerulus ; insulin treatment ; streptozotocin-diabetic rats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The three-dimensional ultrastructure of glomerular basement membrane (GBM) and mesangial matrix (MM) at an early stage of streptozotocin (STZ)-induced diabetes mellitus in rats was examined by the quick-freezing and deep-etching method. In diabetic rats, the GBM inner layer was diffusely enlarged and the meshwork structure not only in the GBM middle layer but also in the MM became markedly irregular due to the rupture of fine fibrils. This irregularity and enlargement of the mesh pores in diabetic rats developed during the experimental period and was significantly different from results in control rats. Insulin treatment from 1 week after STZ injection had significant effects in preventing the ultrastructural changes in the GBM and MM. It is suggested that early insulin treatment has significant effects in preventing size barrier disturbance of GBM and MM in STZ-induced diabetes.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-0428
    Schlagwort(e): Keywords Quick-freezing ; deep-etching ; glomerulus ; insulin treatment ; streptozotocin-diabetic rats.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The three-dimensional ultrastructure of glomerular basement membrane (GBM) and mesangial matrix (MM) at an early stage of streptozotocin(STZ)-induced diabetes mellitus in rats was examined by the quick-freezing and deep-etching method. In diabetic rats, the GBM inner layer was diffusely enlarged and the meshwork structure not only in the GBM middle layer but also in the MM became markedly irregular due to the rupture of fine fibrils. This irregularity and enlargement of the mesh pores in diabetic rats developed during the experimental period and was significantly different from results in control rats. Insulin treatment from 1 week after STZ injection had significant effects in preventing the ultrastructural changes in the GBM and MM. It is suggested that early insulin treatment has significant effects in preventing size barrier disturbance of GBM and MM in STZ-induced diabetes. [Diabetologia (1996) 39: 632–640]
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Acta neurochirurgica 142 (2000), S. 507-511 
    ISSN: 0942-0940
    Schlagwort(e): Keywords: Meningioma; incidental tumour; growth rate; multivariate analysis.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary ¶ The aim of this study was to assess the growth of incidental meningiomas, to establish a strategy for dealing with these tumours.  The cases of 37 patients with a meningioma revealed incidentally by computerized tomography or magnetic resonance imaging, who were followed at least once by an additional imaging study, were reviewed. The tumour volume was calculated, to estimate the annual growth rate of the incidental meningiomas. Nine of the 37 patients (24.3%) showed a considerable increase (the annual growth rate〉1 cu cm/year) in their tumour volume (tumour growth). There was no significant difference in the follow-up period, age, or the volume of tumour between the patients with and without tumour growth. However, a multivariate analysis revealed that the likelihood of tumour growth independently and significantly increased according to a decrease in the age of the patients (Odds ratio 0.18 for one-standard-deviation change (1SD) 12.6 years, p=0.042) and according to an increase in the volume of the tumour (Odds ratio 3.64 for 1SD 4.46 cu cm, p=0.042).  The majority of patients with incidental meningioma can be apparently observed without any surgical intervention, because their annual growth rates are generally less than 1 cu cm/year. However, clinical and radiological observations would be advisable for these patients (especially young patients and patients with a large tumour), in view of the presence of rapidly growing tumours in some of the patients.
    Materialart: Digitale Medien
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  • 10
    ISSN: 0942-0940
    Schlagwort(e): Intracerebral haemorrhage ; spontaneous cerebral haemorrhage ; amyloid angiopathy ; surgery
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Nineteen patients with massive lobar haemorrhage without angiographic lesions received direct or stereotactic surgery, and biopsy specimens were examined histologically. Ten patients (53%) were found to have vessels positive for Congo-red staining, and demonstrating amyloid angiopathy. In the patients with amyloid angiopathy, CT scan and surgical findings were investigated. Subarachnoid haemorrhage (9/10), irregularly shaped haematoma (9/10) and fluid-blood density level in the haematoma cavity (7/10) were frequently found on CT scan. The characteristic surgical findings in patients treated by direct surgery were subarachnoid haemorrhage adjacent to intracerebral haematoma (8/8) and the existence of a tangle of vessels in the haematoma cavity (4/8). Evacuation of haematomas was relatively easy, and difficulty of haemostasis was not encountered during surgery.
    Materialart: Digitale Medien
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