Extension of Linear Response Regime in Weak-Value Amplification Technique

The achievable precision of parameter estimation plays a significant role in evaluating a strategy of metrology.In practice,one may employ approximations in a theoretical model development for simplicity,which,however,will cause systematic error and lead to a loss of precision.We derive the error of maximum likelihood estimation in the weak-value amplification technique where the linear approximation of the coupling parameter is used.We show that this error is positively related to the coupling strength and can be effectively suppressed by improving the Fisher information.Considering the roles played by weak values and initial meter states in the weak-value amplification,we also point out that the estimation error can be decreased by several orders of magnitude by averaging the estimations resulted from different initial meter states or weak values.These results are finally illustrated in a numerical example where an extended linear response regime to the parameter is observed.

Identification of Lightning Stroke and Fault in the Travelling Wave Protection

To resolve the impact of transient high frequency signals induced by lightning stroke on the travelling wave protection of transmission line, a novel identification algorithm is proposed. Using the characteristics of symmetric current wave-form induced by lightning stroke without causing fault and that of asymmetric current waveform generated by fault within a very short time interval, the waveform of transient current above and below time-axes are integrated respec-tively. First, through comparing the relative ratio of them with threshold value, the primary criterion identifying fault and lightning stroke is constructed;Secondly, to improve the reliability of discrimination between lightning stroke with and without causing fault, according to the difference of them, the secondary criterion is also defined. The simulation results and analysis demonstrate that the proposed integral criterions are valid and correct.

Cenozoic low temperature cooling history of the eastern Lhasa terrane:Implications for high-relief topography of external drainage area in the southern Tibetan Plateau

The Tibetan Plateau geographically contains internal and external drainage areas based on the distributions of river flows and catchments.The internal and external drainage areas display similar highelevations,while their topographic reliefs are not comparable;the former shows a large low-relief surface,whereas the latter is characterized by relatively high relief.The eastern Lhasa terrane is a key tectonic component of the Tibetan Plateau.It is characterized by high topography and relief,but the thermal history of its basement remains relatively poorly constrained.In this study we report new apatite fission track data from the eastern part of the central Lhasa terrane to constrain the thermo-tectonic evolution of the external drainage area in the southern Tibetan Plateau.Twenty-one new AFT ages and associated thermal history models reveal that the basement underlying the external drainage area in southern Tibet experienced three main phases of rapid cooling in the Cenozoic.The Paleocene-early Eocene(-60–48 Ma)cooling was likely induced by crustal shortening and associated rock exhumation,due to accelerated northward subduction of the NeoTethys oceanic lithosphere.A subsequent cooling pulse lasted from the late Eocene to early Oligocene(-40–28 Ma),possibly due to the thickening and consequential erosion of the Lhasa lithosphere resulted from the continuous northward indentation of the India plate into Eurasia.The most recent rapid cooling event occurred in the middle Miocene-early Pliocene(-16–4 Ma),likely induced by accelerated incision of the Lhasa River and local thrust faulting.Our AFT ages and published low-temperature thermochronological data reveal that the external drainage area experienced younger cooling events compared with the internal drainage area,and that the associated differentiated topographic evolution initiated at ca.30 Ma.The contributing factors for the formation of the high-relief topography mainly contain active surface uplift,fault activity,and the enhanced incision of the Yarlung River.

An important reference criterion for the selection of GSSP

A study on the relationship between biostratigraphy and seguence stratigraphy in several designated global boundary stratotypes shows that the best way may be to take the GSSP at a point coincident with the base of the first widespread Leading Group biozone above the first flooding surface (FFS) of the relevant third-order seguence. it is suggested that the first flooding surface of the sequence should be an important reference criterion for the selection of GSSP. As the base of the first widespread Leading Group biozone chosen for the definition of GSSP could not be lower than the first flooding surface of the referred seguence, the latter surface may be an important criterion for the recognition and correlation of the chronostratigraphic boundaries.

Zircon U-Pb geochronology of tuffite beds in the Baishugou Formation:Constraints on the revision of Ectasian System at the southern margin of the North China Craton

The Xiamaling Formation of 1.4–1.35 Ga in Jixian Section and adjoining areas represents a unique Ectasian Period(Mesoproterozoic)sedimentary sequence in the North China Craton(NCC).Studies carried out during the last decade have contributed significantly in improving our understanding about the Ectasian sedimentation tectonics in the NCC during this transitional interval between the breakup of Supercontinent Columbia and the assembly of Rodinia.The present study reports,for the first time,tuffite beds interlayered with carbonaceous-siliceous slate-phyllite in the upper Baishugou Formation(western Henan Province),at the southern margin of NCC.The LA-MC-ICPMS U-Pb geochronology of zircons from two tuffite samples has yielded almost identical ages of 1330±10 Ma(MSWD=0.43,N=38)and 1332±10 Ma(MSWD=0.90,N=24),that constrain a 1.33 Ga depositional age(Ectasian Period)for the Baishugou Formation.A close similarity in lithological characteristics and their respective superimposed lithostratigraphic relationships of the Baishugou and Xiamaling formations,underline a comparable depositional environment for them.The high-precision geochronology data on the Baishugou Formation would stimulate a relook into the Meso-Neoproterozoic chronostratigraphic framework of the NCC,and further research would lead to a comprehensive understanding of the geological evolution of the NCC during Ectasian Period and its correlation with analogous global events.

Bioinspired Strategies for Excellent Mechanical Properties of Composites

Developing high-performance composite materials is of great significance as a strong support for high-end manufacturing.However,the design and optimization of composite materials lack a theoretical basis and guidance scheme.Compared with traditional composite materials,natural materials are composed of relatively limited components but exhibit better mechanical properties through ingenious and reasonable synthetic strategies.Based on this,learning from nature is considered to be an effective way to break through the bottleneck of composite design and preparation.In this review,the recent progress of natural composites with excellent properties is presented.Multiple factors,including structures,components and interfaces,are first summarized to reveal the strategies of natural materials to achieve outstanding mechanical properties.In addition,the manufacturing technologies and engineering applications of bioinspired composite materials are introduced.Finally,some scientific challenges and outlooks are also proposed to promote next-generation bioinspired composite materials.