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81.
Small Stress Change Triggering a Big Earthquake: a Test of the Critical Point Hypothesis for Earthquakes
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Whether or not a small stress change can trigger a big earthquake is one of the most important problems related to the critical point hypothesis for earthquakes. We investigate global earthquakes with different focM mechanisms which have different levels of ambient shear stress. This ambient stress level is the stress level required by the earthquakes for their occurrence. Earthquake pairs are studied to see whether the occurrence of the preceding event encourages the occurrence of the succeeding one in terms of the Coulomb stress triggering. It is observed that the stress triggering effect produced by the change of Coulomb failure stress in the same order of magnitudes,about 10-2 MPa, is distinctly different for different focal mechanisms, and thus for different ambient stress levels.For non-strike-slip earthquakes with a relatively low ambient stress level, the triggering effect is more evident,while for strike-slip earthquakes with a relatively high ambient stress level, there is no evident triggering effect.This water level test provides an observational support to the critical point hypothesis for earthquakes. 相似文献
82.
83.
A new method for indirect determination of cetyl-trimethyl ammonium bromide (CTMAB) with NaCl and NH4SCH by floatation and separation of zinc has been studied.The study shows that Zn(Ⅱ) can associate with NH4SCN and CTMAB to form insoluble ternary ion-association complex,and the precipitate can float on the surface of the liquid phase.A good linear relationship is observed between the floatation yield(E%) of Zn(Ⅱ) and the amount of CTMAB.On the ground,CTMAB Can be indirectly determined by determining E% of Zn(Ⅱ).The results were satisfactory. 相似文献
84.
To describe pulsar spin-down,we present a simple combined torque model that takes into account both the standard magnetic dipole radiation and the electromagnetic radiation from the 3P2 superluid vortex neutrons inside neutron star.Using an ordinary exponential model for the magnetic field decay,we derive an analytical formulae for pulsar evolution tracks,The pulsar evolution on the P-P diagram is quite different from that of the standard magnetic dipole radiation model,especially when the superfluid torque or field decay becomes dominant. 相似文献
85.
氘作同位素交换气对除氚后的新鲜氘氚化锂残渣[主要成分是硅锂化合物和二氧化硅,渣中含氚约为0.9443mg/g(渣)]中的微量氚进行氚的计量与回收,为氘氚化锂残渣中氚的回收提供技术支持。 相似文献
86.
We present a new exactly solvable inflation model in which inflation can stop automatically,and in the approximately de sitter limit,we give its power spectrum which can be tested in the future observations of cosmic microwave background anisotropy. 相似文献
87.
A new tpye of high power microwave souce operated at low magnetic filed is proposed and studied by the particle-in-cell (PIC) method.An oversized uniform backward-wave-oscillator-like structure is connected to a tapered slow-wave structure by a resonalt cavity.In this device,the electron beam current is effectively used to yield microwaves with high efficientcy,and the mode is locked in a wide range of diode voltage to reduce the requirement to the voltage wave form.The PIC siumlation results show that a peak microwave power of 2.1 GW (averaged 1.1GW) with a pure TM01 mode at 10.7GHz is radiated with 4.1GW input beam power,the frequency remains approximately the same when the diode voltage changed from 300kV to 700kV. 相似文献
88.
Structural Evolution of Nanostructured γ—Ni—28Fe Alloy Investigated by Using the Internal Friction Technique
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The structural evolution of nanostructured γ-Ni-28Fe alloy(n-Ni-Fe)(grain size d-30nm),synthesized by the mechno-chemical method,was investigated by using the internal friction technique combined with differential scanning calorimetry(DSC) in the temperature range from 300K to 670K.An internal friction peak with typical characteristics of the first-order phase transition was observed in the vicinity of 620K,which corresponds to a broad exothermic process revealed by using DSC.Theses results can be explained as the structural changes from the disordering to the ordering transition in the n-Ni-Fe sample. 相似文献
89.
A water soluble crude polysaccharide has been isolated from the fruiting body of cultivated Cordyceps militarvs(L.)Link.The GC analysis indicated that it contained the monosaccharides of Gal,Man,Glc and GlcA.Their molar ratio is 1.00:1.58:7.89:0.19.The crude polysaccharide was fractionated with ethanol to get three fractions,which were CM-Ⅰand CM-Ⅲ,CM-Ⅱ was further purified to get one homogeneous fraction named CMB.The molecular weight was estimated to be 6000by means of gel filtration.CMB is a greyish white powder.The GC analysis indicated that it was composed of Gal.Man,Glc and the molar ratio is 1.00:1.38:5.10.Partial hydrolysis with an acid.periodate oxidation.Smith degradation.IR,GC and methylation analyses,GC/MS analyses were used for the structure analyses of CMB.Man,(1→6)-linked-Glc,(1→4)-linked-Glc and (1→4)-linked-Gal.Some of (1→4) -linked-Glc and all(1→4)-linked-Gal residues are substituted at 3-O and 6-O respectively,(1→4)-linked-Glc and minor(1→6)-linked-Gle.The nonreduced end is composed of Gal and Glc.The main glycosidic link of CMB is α configuration. 相似文献
90.
A convenient and large-scale preparation of retinoic acid 1 from β-ionone in five steps with 38% overall yield is described.The key steps are the epoxidization of 2 with a new methylated agent and the condensation 4 with tetraethyl methylenediphophonate in one-pot procedure to prepare 6. 相似文献