A stability evaluation method for deep-seated toppling in the upper Lancang river,Southwestern China

Deep-seated toppling in the upper reaches of the Lancang River,southwest China involves deformations exceeding 100 m in depth.The slope deformation is initiated by river downcutting and evolves distinctive characteristics with a depth of river incision.In this study,we propose a system for evaluating the stability of deep-seated toppled slopes in different evolutionary stages.This system contains identification criteria for each evolutionary stage and provides the corresponding stability evaluation methods.Based on the mechanical and kinematic analysis of slope blocks,the specific stage of slope movement can be identified in the field through outcrop mapping,in situ tests,surface displacement monitoring,and adit and borehole explorations.The stability evaluation methods are established based on the limiting equilibrium theory and the strain compatibility between the undisturbed zone and the toppled zone.Finally,several sample slopes in different evolution stages have been investigated to verify the applicability and accuracy of the proposed stability evaluation system.The results indicate that intense tectonic activity and rapid river incision lead to a maximum principal stress ratio exceeding 10 near the slope surface,thus triggering widespread toppling deformations along the river valley.When considering the losses of joint cohesion during the further rotation process,the safety factor of the slope drops by 7%e28%.The self-stabilization of toppling deformation can be recognized by the layer symmetry configuration after the free rotation of the deflected layers.Intensely toppled rock blocks mainly suffer sliding failures beyond the layer symmetry condition.The factor of safety of the K73 rockslide decreased from 1.17 to 0.87 by considering the development of the potential sliding surface and the toesaturated zone.

Choledocholithiasis caused by anatomical variation of cystic duct: A case report

Laparoscopic cholecystectomy(LC)has gradually become the first choice for the treatment of cholecystolithiasis in recent years.Iatrogenic bile duct injury(IBDI)is an important clinical problem in LC.The anatomical variation of the cystic duct increases the probability of IBDI and the difficulty of operation.We present a case of a 44-year-old male with a anatomical variation of the cystic duct complicated with cholecystolithiasis and choledocholithiasis,who successfully underwent choledocholithotomy,choledochoscopic exploration and T-tube drainage surgery.The patient recovered well and was discharged home on postoperative day 10.The T-tube was removed at 1 month postoperatively after cholangiography examination of no choledocholithiasis left.

Analysis of Household Management Behavior in the Reclamation and Agricultural Area under Different Land Systems

In the paper, three farms of Jiansanjiang Farming Bureau and five villages in of Dayushu Town in Fujin county randomly were taken as data sources for the investigation of household behavior of reclamation and agricultural area under different land systems, and it can be concluded that the main content included production scale, arable land use structure, household behavior and economic benefits. By comparison and analysis, the advantages and disadvantages of reclamation and agricultural area can be found, which could provide references for agricultural land reform for achieving a more suitable socio-economic of efficient use and sustained and healthy development of agriculture.

Weight Analysis of Impact Factors of Interbedded Anti-Inclined Slopes Block-Flexure Toppling Based on Support Vector Regression

Block-flexure toppling failure is frequently encountered in interbedded anti-inclined rock(IAR)slopes,and seriously threatens the construction of hydropower infrastructure.In this study,we first investigated the Lean Reservoir area’s geological setting and the Linda landslide’s characteristics.Then,uniform design and random design were used to design 110 training datasets and 31 testing datasets,respectively.Afterwards,the toppling response was obtained by using the discrete element code.Finally,support vector regression was used to obtain the influence weights of 21 impact factors.The results show that the influence weight of the slope angle and rock formation dip angle on the toppling deformation among tertiary impact factors is 25.96%and 17.28%,respectively,which are much greater than the other 19 impact factors within the research range.For the primary impact factors,the influence weight is sorted from large to small as slope geometry parameters,joints parameters,and rock mechanics parameters.Joints parameters,especially the geometric parameters,cannot be ignored when evaluating the stability of IAR slopes.Through numerical simulation,it was qualitatively determined that failure surfaces of slopes were controlled by cross joints and that the rocks in the slope toe play a role in preventing slope deformation.

Study on Geomechanical and Physical Models of Necking-Type Slopes

A simplified geomechanical model was proposed by considering three typical neckingtype slopes;this model lays a foundation for the further investigation of the deformation behaviors of such slopes.Three physical models of necking-type slopes were built according to the geomechanical model with slope evolution stages.Finally,preliminary calculations related to the arching effect in the physical model were conducted.Three evolution stages of necking-type slopes,namely,the initial stage,compression stage,and failure stage,were presented based on the formation and disappearance of the arching effect within the slope.The specific parameters of the geomechanical model were given.In the setup of the tilting test,the failure angle of the necking-type slope model was calculated to be approximately 50°with a large lateral resistance coefficient.The proposed geomechanical model and physical models of necking-type slopes provide guidance for the establishment of geomechanical and physical models of landslides at specific sites.

Failure mechanisms in flexible electronics

The rapid evolution of flexible electronic devices promises to revolutionize numerous fields by expanding the applications of smart devices.Nevertheless,despite this vast potential,the reliability of these innovative devices currently falls short,especially in light of demanding operation environment and the intrinsic challenges associated with their fabrication techniques.The heterogeneity in these processes and environments gives rise to unique failure modes throughout the devices'lifespan.To significantly enhance the reliability of these devices and assure long-term performance,it is paramount to comprehend the underpinning failure mechanisms thoroughly,thereby,enabling,optimal design solutions.A myriad of investigative efforts have been dedicated to unravel these failure mechanisms,utilizing a spectrum of tools from analytical models,numerical methods,to advanced characterization methods.This review delves into the root causes of device failure,scrutinizing both the fabrication process and the operation environment.Next,We subsequently address the failure mechanisms across four commonly observed modes:strength failure,fatigue failure,interfacial failure,and electrical failure,followed by an overview of targeted characterization methods associated with each mechanism.Concluding with an outlook,we spotlight ongoing challenges and promising directions for future research in our pursuit of highly resilient flexible electronic devices.

Roles of Multisourced Fluids in the Formation of Sandstone-Hosted Uranium Deposits in the SW Songliao Basin, NE China

The sandstone-hosted uranium deposits in the SW Songliao Basin differ from typical sandstone-hosted uranium deposits in terms of the geological features of the ore-deposits,including the geometry of the orebodies,mineral assemblage and petrography.Detailed drill core and microscopic observations,scanning electron microscopy(SEM),electron microprobe analysis(EMPA),heavy mineral concentrates,and fluid inclusion studies of the Upper Cretaceous Yaojia Formation,i.e.,the uranium-bearing layer,were integrated to investigate the roles of hydrothermal fluids in the formation of these uranium deposits.We found that the kaolinite alteration is developed in the mineralized zones,but it is less common in the peripheral areas.The fluid inclusions are hydrothermal fluids with a medium-low temperature(67 to 179 ℃) and a high salinity(5.9 wt.% to 20.1 wt.%).According to the analyses,three kinds of hydrothermal fluids,i.e.,the acid fluid,the groundwater heated by the mafic magma,and the alkaline fluid rich in Ca^(2+) and CO_(3)^(2-),were identified.The fluids might have low U content,but they have participated in the formation of the uranium deposits successively.Kaolinite formed by the acid-hydrothermal fluid absorbed large amounts of uranium.Subsequently,the thermal energy from the hydrothermal fluids changed the intrastratal redox environment and increased the solubility of the uranium minerals in the fluid.The alkaline-hydrothermal fluid rich in Ca^(2+) and C0_(3)^(2-) facilitated the formation of stable Ca-U(Ⅵ)-CO_(3) complex,which led to the enrichment of soluble uranium in solution,and final precipitation as pitchblende,brannerite and Ti-bearing uranium minerals in the uranium ores.

Accurate closed-form eigensolutions of three-dimensional panel flutter with arbitrary homogeneous boundary conditions

Highly accurate closed-form eigensolutions for flutter of three-dimensional(3D)panel with arbitrary combinations of simply supported(S),glide(G),clamped(C)and free(F)boundary conditions(BCs),such as cantilever panels,are achieved according to the linear thin plate theory and the first-order piston theory as well as the complex modal analysis,and all solutions are in a simple and explicit form.The iterative Separation-of-Variable(iSOV)method proposed by the pre-sent authors is employed to obtain the highly accurate eigensolutions.The flutter mechanism is studied with the benefit of eigenvalue properties from mathematical senses.The effects of boundary conditions,chord-thickness ratios,aerodynamic damping,aspect ratios and in-plane loads on flut-ter properties are examined.The results are compared with those of Kantorovich method and Galerkin method,and also coincide well with analytical solutions in literature,verifying the accu-racy of the present closed-form results.It is revealed that,(A)the flutter characteristics are domi-nated by the cross section properties of panels in the direction of stream flow;(B)two types of flutter,called coupled-mode flutter and zero-frequency flutter which includes zero-frequency single-mode flutter and buckling,are observed;(C)boundary conditions and in-plane loads can affect both flutter boundary and flutter type;(D)the flutter behavior of 3D panel is similar to that of the two-dimensional(2D)panel if the aspect ratio is up to a certain value;(E)four to six modes should be used in the Galerkin method for accurate eigensolutions,and the results converge to that of Kantorovich method which uses the same mode functions in the direction perpendicular to the stream flow.The present analysis method can be used as a reference for other stability issues characterized by complex eigenvalues,and the highly closed-form solutions are useful in parameter designs and can also be taken as benchmarks for the validation of numerical methods.