Early Devonian Post-collisional Granitic Magmatism in the North Qilian Orogenic Belt,Western China:Insights into Lithospheric Delamination and Orogenic Collapse

Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identified in the North Qilian Orogenic Belt(NQOB).This paper reports an integrated study of petrology,whole-rock geochemistry,Sm-Nd isotope and zircon U-Pb dating,as well as Lu-Hf isotopic data,for two Early Devonian intrusive plutons.The Yongchang and Chijin granites yield zircon U-Pb ages of 394-407 Ma and 414 Ma,respectively.Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium-rich minerals,LREE-enriched patterns with negative Eu anomalies and a negative correlation between P_(2)O_(5) and SiO_(2) contents,consistent with geochemical features of I-type granitoids.Zircons from the studied granites display negative to weak positive ε_(Hf)(t)values(−5.7 to 2.1),which agree well with those of negative ε_(Nd)(t)values(−6.4 to−2.9)for the whole-rock samples,indicating that they were derived from the partial melting of Mesoproterozoic crust.Furthermore,low Sr/Y ratios(1.13-21.28)and high zircon saturation temperatures(745℃ to 839℃,with the majority being>800℃)demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source.Taken together,the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle-derived magmas at high-temperature and low-pressure conditions during postcollisional extensional collapse.The data obtained in this study,when viewed in conjunction with previous studies,provides more information about the tectonic processes that followed the closure of the North Qilian Ocean.The tectonic transition from continental collision to post-collisional delamination could be constrained to~430 Ma,which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon ε_(Hf)(t)values for granitoids.A two-stage tectonic evolution model from continental collision to post-collisional extensional collapse for the NQOB includes(a)continental collision and crustal thickening during ca.455-430 Ma,characterized by granulite-facies metamorphism and widespread low-Mg adakitic magmatism;(b)post-collisional delamination of thickened continental crust and extensional collapse of orogen during ca.430-390 Ma,provided by coeval high-Mg adakitic magmatism,A-type granites and I-type granitoids with low Sr-Y ratios.

Roof collapse mechanism of weak surrounding rock for deep-buried tunnels under high geostress conditions

High geostress,a typical attribute of tunnels located at significant depths,is crucial in causing stress-induced failure and influencing the stability of the tunnel crown.This study developed an analytical method for the failure mechanism that occurs in deep-buried tunnel roofs,taking into account the influence of geostress.The limit analysis theory was utilized for deriving analytical solutions about the geometry of the collapsing surface and the limit supporting pressure.The collapsing surface obtained by the analytical solution was validated by the findings of the physical model test,which shows a high level of agreement with the actual one.An extensive investigation was done to explore the effects of the lateral pressure coefficients,the tunnel buried depth,the geological conditions of the surrounding rock,the long-short axis ratio,and the size of the tunnel profile.The findings indicate that an increase in the lateral pressure coefficient from 0.5 to 1.5 results in a reduction in the height of the collapsing zone by 2.08 m and the width of the collapsing zone by 1.15 m,while simultaneously increases the limit supporting pressure by 18.9%.The proposed upper bound method accurately determines the limit supporting pressure and the geometry of the collapsing surface,which aligns well with the results acquired through numerical modelling and on-site monitoring in actual engineering applications.The proposed analytical method can serve as a reference for similar crown failure issues of deep-buried tunnels.

Collapse Behavior of Pipe-Framed Greenhouses with and without Reinforcement under Snow Loading:A 3-D Finite Element Analysis

The present paper first investigates the collapse behavior of a conventional pipe-framed greenhouse under snow loading based on a 3-D finite element analysis,in which both geometrical and material non-linearities are considered.Three snow load distribution patterns related to the wind-driven snow particle movement are used in the analysis.It is found that snow load distribution affects the deformation and collapse behavior of the pipe-framed greenhouse significantly.The results obtained in this study are consistent with the actual damage observed.Next,discussion is made of the effects of reinforcements by adding members to the basic frame on the strength of the whole structure,in which seven kinds of reinforcement methods are examined.A buckling analysis is also carried out.The results indicate that the most effective reinforcement method depends on the snow load distribution pattern.

Progressive Collapse Resistance of a New Staggered Story Isolated System

A new staggered isolated system developed from the mid-story isolated system is the new staggered story isolated system. There are not many studies on this structure currently. In this study, an 18-story new staggered story isolated system model is established using SAP2000. The dynamic nonlinear dynamic alternate method is used to analyze the structure against progressive collapse. Results show that the structure has good resistance to progressive collapse, and there is no progressive collapse under each working condition. The progressive collapse does not occur for the case of removing only one vertical structural member of the new staggered of isolated system. The side column has big influence on this isolated structures’ progressive collapse;the removal of vertical structural member of the isolation layer has less impact on the structure than the removal of the bottom vertical structural member. After the removing of the member, the internal force of the structure will be redistributed, and the axial force of the adjacent columns will change obviously, showing a trend of “near large and far small”.

Distribution and Susceptibility Assessment of Collapses and Landslides in the Riparian Zone of the Xiaowan Reservoir

The southwest alpine gorge region is the major state base of hydropower energy development in China and hence planned many cascading hydropower stations. After the reservoir impoundment, the intense water level fluctuations under the interaction of cascade dams operating and the mountainous flooding, usually cause bank collapse, landslide and debris flow hazards. The Xiaowan reservoir(XWR), for example, as the ‘dragon head' meg reservoir located in the middle mainstream of Lancang River, have resulted in a series of geohazards during its building and operating. In this study, we investigated the number and surface area of collapses and landslides(CLs) occurred in the water level fluctuations zone(WLFZ) of XWR using remote sensing images of Gaofen-1 and Google Earth; evaluated the CLs susceptibility using information value method. The results presented that the total WLFZ area of 87.03 km2 and 804 CLs masses with a total area of 1.98 km2 were identified in the riparian zone of XWR. CLs mainly occurred at an elevation of 1190–1240 m, and the CLs density increased with an increase in altitude. The WLFZ with a slope gradient of 25°– 45° is the main CLs distribution area that accounts for more than half of the total CLs area. The susceptibility assessment revealed that high and very high susceptibility zones are generally distributed along zones with an elevation of 1210–1240 m, a slope degree of 25°–45° and a slope aspect perpendicular to the direction of Lancang River. Furthermore, these susceptible zones are close in distance to the dam site and tend to be in the riparian zones with the formation lithology of Silurian strata. These results provide a valuable contribution to prevent and control geohazards in the XWR area. Moreover, this study offers a constructive sample of geohazards assessment in the riparian zone of large reservoirs throughout the mountains of southwest China.

Observation of the poloidally asymmetrical density perturbation of sawtooth collapse on J-TEXT

The detailed density perturbations provided by the advanced polarimeter-interferometer system(Polaris) during sawtooth collapse on the Joint Texas Experimental Tokamak(J-TEXT) are reported in this article.During a sawtooth collapse and the crash of plasma pressure at the center,it is found that the increase in density in the region between the inversion radius and mixing radius is poloidally asymmetrical,while the increase in temperature is poloidally symmetrical.The poloidal location where the density increases is dependent on the phase of the precursory m/n=1/1 kink mode.It is always out of phase with the hot core of the m/n=1/1 mode.The behaviors of density perturbations during sawtooth collapse observed in J-TEXT are beyond the expectations of the standard model,and this can shed new light on the understanding of sawtooth collapse.

Experimental and Numerical Study on Progressive Collapse Analysis of a Glulam Frame Structure:I.Side Column Exposed to Fire

This paper presents experimental and numerical investigations on progressive collapse behavior of a two-story glulam frame when the side column is exposed to ISO834 standard fire.The collapse mechanism initiated by fire is identified.The experimental results show that the progressive collapse of a glulam frame could be described for three stages,namely bending effect stage,catenary effect stage and failure stage,respectively.These stages are discussed in detail to understand the structural behavior before and during collapse.It is demonstrated that the entire frame slopes towards the side of the heated column,and the“overturning”collapse occurs eventually.The catenary effect of beams is the main reason for the progressive collapse of the frame.In addition,a finite element model of a glulam frame is established to simulate the progressive collapse behavior.The effects of axial loads on the columns are summarized.The numerical simulation results agree well with the experimental results,which could verify the effectiveness and practicability of finite element simulation.Furthermore,the progressive collapse resistance of the frame in practical design were proposed.

Slope Collapse Detection Method Based on Deep Learning Technology

Sofar,slope collapse detectionmainlydepends onmanpower,whichhas the followingdrawbacks:(1)lowreliability,(2)high risk of human safe,(3)high labor cost.To improve the efficiency and reduce the human investment of slope collapse detection,this paper proposes an intelligent detection method based on deep learning technology for the task.In thismethod,we first use the deep learning-based image segmentation technology to find the slope area from the captured scene image.Then the foreground motion detection method is used for detecting the motion of the slope area.Finally,we design a lightweight convolutional neural network with an attentionmechanismto recognize the detected motion object,thus eliminating the interference motion and increasing the detection accuracy rate.Experimental results on the artificial data and relevant scene data show that the proposed detection method can effectively identify the slope collapse,which has its applicative value and brilliant prospect.

Analysis on the Failure Causes of the Collapsed Tubing in an Oil Well

Due to the influence of multiple factors such as internal and external formation and mechanical pressure, medium corrosion and construction operation environment, a tubing collapse failure occurred in an oil well. In order to determine the failure cause of the tubing, physical and chemical tests and mechanical properties analysis were carried out on the failed tubing sample and the intact tubing. The results show that the chemical composition, ultrasonic and magnetic particle inspection, metallographic test, Charpy impact energy and external pressure mechanical property test of the failed tubing all meet the requirements of API Spec 5CT-2021 standard, but the yield strength of the failed tubing does not meet the requirements of API Spec 5CT-2021 standard. Through the analysis of the working conditions, it can be seen that the anti-extrusion strength of the tubing collapse does not meet the API 5C3 anti-extrusion strength standard. The failure type of the well tubing is tubing collapse caused by large internal and external pressure difference.

基于Slide的研山铁矿高陡边坡稳定性分析

露天矿山边坡稳定性对采场安全生产至关重要。为探究边坡施工过程中的安全隐患,以研山铁矿高陡边坡为研究对象,考虑爆破震动及地震作用荷载,运用Slide二维边坡数值模拟软件对典型剖面进行稳定性计算。结果表明:在正常工况条件、爆破震动及地震作用下,边坡整体安全系数符合要求,整体处于稳定状态。但在爆破震动及地震作用下,边坡局部安全系数介于临界值,可能存在局部滑坡风险。为保证采场生产安全,提出了相应的边坡管理预防措施,为相关实践工作提供一定参考。

Custom Made Fenestrated Stent Graft Collapse after Thoracic Endovascular Aortic Repair: A Case Report

We present a case of stent graft collapse after performing thoracic endovascular aortic repair with a custom-made fenestrated stent graft. The patient was a 70-year-old woman with an asymptomatic aneurysm of the distal aortic arch, and thoracic endovascular aortic repair was performed. The patient showed a blood pressure difference between the left arm and the right arm on postoperative day (POD) 17 prompting the performance of a chest computed tomography scan which revealed stent graft collapse. She then underwent staged debranching of thoracic endovascular aortic repair. Stent graft collapse is a rare but well-described complication of thoracic endovascular repair. Therefore, patients who undergo such a procedure should be carefully monitored for signs and symptoms, which suggest the possibility of stent collapse.

Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors

Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental protection.However,the placement of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine slides.Historical incidents have highlighted the substantial damage to pipelines due to slides.Specifically,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant threat.Accurately assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline safety.This study aimed to provide a comprehensive overview of recent advancements in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact forces.These factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of pipelines.Additionally,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with pipelines.Building upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive understanding of these results is essential for the sustainable development of deep-sea pipeline projects associated with seabed resource development and the implementation of disaster prevention measures.

CrossLinkNet: An Explainable and Trustworthy AI Framework for Whole-Slide Images Segmentation

In the intelligent medical diagnosis area,Artificial Intelligence(AI)’s trustworthiness,reliability,and interpretability are critical,especially in cancer diagnosis.Traditional neural networks,while excellent at processing natural images,often lack interpretability and adaptability when processing high-resolution digital pathological images.This limitation is particularly evident in pathological diagnosis,which is the gold standard of cancer diagnosis and relies on a pathologist’s careful examination and analysis of digital pathological slides to identify the features and progression of the disease.Therefore,the integration of interpretable AI into smart medical diagnosis is not only an inevitable technological trend but also a key to improving diagnostic accuracy and reliability.In this paper,we introduce an innovative Multi-Scale Multi-Branch Feature Encoder(MSBE)and present the design of the CrossLinkNet Framework.The MSBE enhances the network’s capability for feature extraction by allowing the adjustment of hyperparameters to configure the number of branches and modules.The CrossLinkNet Framework,serving as a versatile image segmentation network architecture,employs cross-layer encoder-decoder connections for multi-level feature fusion,thereby enhancing feature integration and segmentation accuracy.Comprehensive quantitative and qualitative experiments on two datasets demonstrate that CrossLinkNet,equipped with the MSBE encoder,not only achieves accurate segmentation results but is also adaptable to various tumor segmentation tasks and scenarios by replacing different feature encoders.Crucially,CrossLinkNet emphasizes the interpretability of the AI model,a crucial aspect for medical professionals,providing an in-depth understanding of the model’s decisions and thereby enhancing trust and reliability in AI-assisted diagnostics.

Visualization of Vapor Film Collapse Behavior with Complexity on Quenching Process by Cellular Automaton

The vapor film collapse that occurs in the quenching process is complicated and affects the heat treatment quality and its distortion.In order to incorporate it into the MBD(Model Based Development)technology required these days,it is necessary to predict the quality of heat treatment by CAE(Computer Added Engineering),shorten the product development period.The calculation of the vapor film collapses in a simple and practical time in order to improve the product performance.However,in the past,in order to formulate the vapor film collapse on a simulation,it was necessary to perform a very large amount of computational calculation CFD(computational fluid dynamics),which was a problem in terms of computer resources and the model of vapor film collapse.In addition,this phenomenon has a complexity behavior of the phenomenon in iterative processing,which also complicates the calculation.In this study,the vapor film collapse phenomenon is easily visualized using self-organized cellular automaton simulation which includes the phenomena of“vapor film thickness and its fluctuation”,“flow disturbance”,“surface step of workpiece”,and“decrease of cooling due to r shape of surface”.The average cooling state and repeated fluctuations of the cooling state were reproduced by this method.

Airblast evolution initiated by Wangjiayan landslides in the M_(s)8.0 Wenchuan earthquake and its destructive capacity analysis

Airblasts,as one common phenomenon accompanied by rapid movements of landslides or rock/snow avalanches,commonly result in catastrophic damages and are attracting more and more scientific attention.To quantitatively analyze the intensity of airblast initiated by landslides,the Wangjiayan landslide,occurred in the Wenchuan earthquake,is selected here with the landslide propagation and airblast evolution being studied using FLUENT by introducing the Voellmy rheological law.The results reveal that:(1)For the Wangjiayan landslide,its whole travelling duration is only 12 s with its maximum velocity reaching 36 m/s at t=10 s;(2)corresponding to the landslide propagation,the maximum velocity,28 m/s,of the airblast initiated by the landslide also appears at t=10 s with its maximum pressure reaching594.8 Pa,which is equivalent to violent storm;(3)under the attack of airblast,the load suffered by buildings in the airblast zone increases to 1300 Pa at t=9.4 s and sharply decreased to-7000 Pa as the rapid decrease of the velocity of the sliding mass at t=10 s,which is seriously unfavorable for buildings and might be the key reason for the destructive collapse of buildings in the airblast zone of the Wangjiayan landslide.

基于Slide2的某铁矿尾矿库坝体稳定性分析

尾矿库是冶金矿山的重要附属设施,一旦失事将造成严重的环境污染和重大损失,尾矿库安全的核心在于尾矿坝是否稳定。通过采用Slide2软件,根据岩土工程勘察资料,建立山西某铁矿尾矿库坝体典型剖面的二维数值模型,对坝体三种运行工况下的渗流稳定性和坝坡稳定性进行分析,以确定尾矿库的安全性,并分析Slide2软件应用于尾矿坝稳定性分析中的可靠性和功能性。

Collapsed Cone光子束剂量计算方法研究

剂量计算是放射治疗计划系统的核心,与常用的笔形束剂量计算方法相比,collapsed cone卷积/叠加剂量计算方法具有更高的计算精度,为此我们研究了collapsed cone卷积/叠加剂量计算方法及加速算法,开发了一套基于collapsed cone卷积/叠加剂量计算方法的光子束放射治疗计划系统,并运用蒙特卡罗方法对剂量计算的准确性进行了验证。实验结果表明剂量计算误差与射束能量、射野尺寸以及剂量计算分辨率有关,当天顶角增量和方位角增量分别取3.75°和15°时,对于3～20 cm的方野,剂量计算误差均小于1.5%。所开发的collapsed cone光子束剂量计算方法准确可靠,可望应用于临床。

Collapse方程的对称及其群不变解

主要探讨 Collapse方程的对称及其李代数 ,通过对称确定该方程的单参数不变群 ,并利用对称约化给出

支气管镜在儿童Slide气管成形术中的应用

目的 总结支气管镜在儿童Slide气管成形术中的作用。方法 回顾性分析2017—2020年湖南省人民医院收治的4例气管狭窄患儿的诊疗经过,总结支气管镜在Slide气管成形术术前评估、术中定位与测量及术后创面评估和治疗中的作用。结果 Slide气管成形术术前支气管镜评估显示,4例患儿中3例存在完全气管环,2例合并肺动脉吊带,2例存在多处狭窄。3例在该院完成Slide气管成形术,术中支气管镜下判断狭窄段中点及测量狭窄段长度,协助离断气管狭窄段,术后灌洗明确病原;1例外院Slide气管成形术术后9个月出现瘢痕牵拉,经支气管镜下介入治疗好转。2例术后第4天支气管镜下发现气管黏膜改变,调整治疗方案;2例术后1个月出现肉芽增生,经支气管镜下冷冻治疗好转。1例因吻合口坏死放弃治疗死亡,存活的3例随访6个月以上,预后可,但均存在气管支气管软化。结论 支气管镜可用于气管狭窄患儿Slide气管成形术的管理,有助于术后康复及随访。

The Corruption and Collapse of the Old Southern Traditional Values in The Sound and the Fury

The Sound and the Fury is the novel which Faulkner spent the most effort and is the writer's favourite book. The title of this book is taken from Shakespeare's tragedy Macbeth, implying the multiple themes of the novel. One theme is to discuss the corruption and collapse of the old southern traditional values through the description of the Compson family's corruption and the decline of southern plantation economy. In the novel, Faulkner seeks the way out for American south during the transformation period though the figures he created, but no one is successful in getting out of the bad influence of the Old South.