3,305 research outputs found
Study on the Rheological Properties and Constitutive Model of Shenzhen Mucky Soft Soil
In order to obtain the basic parameters of numerical analysis about the time-space effect of the deformation occurring in Shenzhen deep soft-soil foundation pit, a series of triaxial consolidated-undrained shear rheology tests on the peripheral mucky soft soil of a deep foundation pit support were performed under different confining pressures. The relations between the axial strain of the soil and time, as well as between the pore-water pressure of the soil and time, were achieved, meanwhile on the basis of analyzing the rheological properties of the soil, the relevant rheological models were built. Analysis results were proved that the rheology of Shenzhen mucky soft soil was generally viscous, elastic, and plastic, and had a low yield stress between 90 and 150 kPa. The increase in pore-water pressure made the rheological time effect of the mucky soft soil more remarkable. Thus, the drainage performance in practical engineering should be improved to its maximum possibility extent to decrease the soft-soil rheological deformation. Lastly, a six-component extended Burgers model was employed to fit the test results and the parameters of the model were determined. Findings showed that the extended Burgers model could satisfactorily simulate the various rheological stages of the mucky soft soil. The constitutive model and the determination of its parameters can be served as a foundation for the time-space effect analysis on the deformation of deep soft-soil foundation pits
Joint constraint on the jet structure from the short GRB population and GRB 170817A
The nearest GRB 170817A provided an opportunity to probe the angular
structure of the jet of this short gamma-ray burst (SGRB), by using its
off-axis observed afterglow emission. It is investigated that whether the
afterglow-constrained jet structures can be consistent with the luminosity of
the prompt emission of GRB 170817A. Furthermore, by assuming that all SGRBs
including GRB 170817A have the same explosive mechanism and jet structure, we
apply the different jet structures into the calculation of the flux and
redshfit distributions of the SGRB population, in comparison with the
observational distributions of the Swift and Fermi sources. As a result, it is
found that the single-Gaussian structure can be basically ruled out, whereas
the power-law and two-Gaussian models can in principle survive.Comment: 9 pages,6 figure
A supra-massive magnetar central engine for short GRB 130603B
We show that the peculiar early optical and in particular X-ray afterglow
emission of the short duration burst GRB 130603B can be explained by continuous
energy injection into the blastwave from a supra-massive magnetar central
engine. The observed energetics and temporal/spectral properties of the late
infrared bump (i.e., the "kilonova") are also found consistent with emission
from the ejecta launched during an NS-NS merger and powered by a magnetar
central engine. The isotropic-equivalent kinetic energies of both the GRB
blastwave and the kilonova are about erg, consistent
with being powered by a near-isotropic magnetar wind. However, this relatively
small value demands that most of the initial rotational energy of the magnetar
is carried away by gravitational wave
radiation. Our results suggest that (i) the progenitor of GRB 130603B would be
a NS-NS binary system, whose merger product would be a supra-massive neutron
star that lasted for about seconds; (ii) the equation-of-state of
nuclear matter would be stiff enough to allow survival of a long-lived
supra-massive neutron star, so that it is promising to detect bright
electromagnetic counterparts of gravitational wave triggers without short GRB
associations in the upcoming Advanced LIGO/Virgo era.Comment: Five pages including 1 Figure, to appear in ApJ
Reduced glutamine synthetase activity alters the fecundity of female Bactrocera dorsalis (Hendel)
Glutamine synthetase (GS) is a key enzyme in glutamine synthesis and is associated with multiple physiological processes in insects, such as embryonic development, heat shock response, and fecundity regulation. However, little is known about the influence of GS on female fecundity in the oriental fruit fly, Bactrocera dorsalis. Based on the cloning of BdGSs, mitochondrial BdGSm and cytoplasmic BdGSc, we determined their expressions in the tissues of adult B. dorsalis. BdGSm was highly expressed in the fat body, while BdGSc was highly expressed in the head and midgut. Gene silencing by RNA interference against two BdGSs isoforms suppressed target gene expression at the transcriptional level, leading to a reduced ovarian size and lower egg production. The specific inhibitor L-methionine S-sulfoximine suppressed enzyme activity, but only the gene expression of BdGSm was suppressed. A similar phenotype of delayed ovarian development occurred in the inhibitor bioassay. Significantly lower expression of vitellogenin and vitellogenin receptor was observed when GS enzyme activity was suppressed. These data illustrate the effects of two GS genes on adult fecundity by regulating vitellogenin synthesis in different ways
The Application of Stereo Anti-eccentrically Teaching Methods in Traditional Chinese Qigong Course
目的 探讨立体带功防偏模式在中医气功教学中的应用。方法 从气功偏差的严重后果及目前的教学现状、立体带功防偏气功教学法的目标和意义、立体带功防偏气功教学法的具体步骤等方面进行了详细的介绍。结果 2012-2013年医学气功学课程11个班级723个学生中,出现不适感的人数仅占1.8%,在一周内不适感消失的占61.5%,两周内不适感消失者达100%,没有一例严重偏差的出现,达到了安全教学的目的。结论 立体带功防偏气功教学法可以及时发现学生出现偏差的苗头并及时纠正,提高了教学的安全性,因此值得推广。Objective: To explore the use of stereo anti-eccentrically Chinese qigong teaching mode. Method: To introduce the concrete steps of Qigong teaching methods from Qigong serious consequences,deeviation and the present teaching situation, the goal and significance of stereo anti-eccentrically qigong teaching methods etc. Result: In 2013, 6 classes and 498 students, only 23(4.61%)students appeared discomfort. Within a week the improvement of discomfort students is 16(69.56%),disappearance of discomfort students is 5(21.73%), two weeks later,disappeared discomfort students achieve 100%, have no emergence of severe deviation, reached the safety of teaching purpose. Conclusion: Stereo anti-eccentrically Qigong teaching method can find the first hint of deviation and correct them in time, can improve the security of teaching. so it is worth spreading
Difference in Thermotolerance Between Green and Red Color Variants of the Japanese Sea Cucumber, Apostichopus japonicus Selenka: Hsp70 and Heat-Hardening Effect
We studied thermal tolerance limits, heat-hardening, and Hsp70 to elucidate the difference in thermotolerance between two color variants of the sea Cucumber Apostichopus japonicus. Green and Red variants Occupy different habitats and have different aestivation responses to high temperature in summer. In the absence of heat-hardening the variants showed no difference in the temperature at which 50% of the individuals died: Green 31.49 degrees C; Red, 31.39 degrees C. However. Green specimens acquired higher thermotolerance than Red after a prior Sublethal heat exposure. After 72 h of recovery from a heat-hardening treatment (30 degrees C for 2 h) the survival of Green variants was more than 50% and that of Red wits less than 5% when they were treated at 33 degrees C for 2 h. Levels of mRNA and protein for Hsp70 were significantly higher in Green than Red after the heat shock of 30 degrees C, and the stability of hsp70 mRNA of Green was significantly higher than that of Red. Our findings suggest that within the same species, different variants that have similar thermal limits in the absence of heat-hardening can acquire different thermotolerances after a prior sublethal heat shock. The difference in induced thermotolerance between Green and Red is closely related to the expression pattern of Hsp70, which was partly governed by the stability of hsp70 mRNA
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