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A Comprehensive Study on the Consequences of Gap-Graded Sands Considering the Loss of Fine Particles

Journal of Earth Science 2024年第2期35卷 597-612页

作者： Weiping Liu yu gan yunwei Cui Faming Huang Lina Hu School of Civil Engineering and Architecture Nanchang UniversityNanchang330031China

Water and sand leakage disasters are likely to occur during construction in water-rich sand layer areas,resulting in ground collapse.The stress-strain action characteristics of discontinuous graded sand under different internal erosion degrees,and the evolution mechanism of water and sand leakage disasters caused by the internal erosion need to be further explored.Therefore,this paper takes the discontinuous graded sand in a water rich sand layer area in Nanchang City of China as the research object.Considering the influence of different fine particle losses(0,10%,20%and 30%)under the internal erosion of sand,the salt solution method is used to realize the specified loss of fine particles in the internal erosion.The stress-strain behavior after the loss of fine particles due to internal erosion is studied by triaxial shear test.Meanwhile,the physical model test and PFC-CFD method are both used to study the evolution rules of water and sand leakage disaster considered the influence of internal erosion degrees.Results show that:(1)under the same confining pressure,the peak failure strength of sand samples decreases along with the increase of fine particle loss.(2)In the water and sand leakage test of saturated sand,a natural filter channel is formed above the observed soil arch.The greater the loss of fine particles,the steeper and wider the collapse settlement area.(3)The relationship between the cumulative amount of water and sand leakage and time is nonlinear.The total mass loss of sand increases along with the increase of internal erosion degree.(4)After the soil arch is formed around the damaged opening,the sand continues to converge above the soil arch under the action of water flow,resulting in the dense convergence of contact force chains.

关键词： sandy soil internal erosion stress and strain water and sand leakage PFC3D engineering geology

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New Splitting Algorithms for Multiplicative Noise Removal Based on Aubert-Aujol Model

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Numerical Mathematics(Theory,Methods and Applications) 2022年第2期15卷 415-441页

作者： yu gan Jie Zhang Huibin Chang School of Mathematical Sciences Tianjin Normal UniversityTianjinChina Department of Mathematics The University of Hong KongHong KongSARChina

In this paper,we propose new algorithms for multiplicative noise removal based on the Aubert-Aujol(AA)model.By introducing a constraint from the forward model with an auxiliary variable for the noise,the NEMA(short for Noise Estimate based Multiplicative noise removal by alternating direction method of multipliers(ADMM))is firstly given.To further reduce the computational cost,an additional proximal term is considered for the subproblem with regard to the original variable,the NEMA_(f)(short for a variant of NEMA with fully splitting form)is further proposed.We conduct numerous experiments to show the convergence and performance of the proposed algorithms.Namely,the restoration results by the proposed algorithms are better in terms of SNRs for image deblurring than other compared methods including two popular algorithms for AA model and three algorithms of its convex variants.

关键词： Alternating direction method of multipliers image denoising and deblurring multiplicative noise total variation

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浅析歙砚纹理的成因及发墨机制

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岩石矿物学杂志 2024年第3期43卷 562-574页

作者：唐甘宇赖勇北京大学造山带与地壳演化教育部重点实验室北京100871

歙砚作为我国四大名砚之一,具有很高的经济及艺术价值。为探究歙砚特有纹理的成因和歙砚发墨机理,对江西婺源的歙砚样本进行了光学显微镜、环境扫描电镜、电子探针和能谱等的观察和测试,结果表明歙砚原石的主要组成矿物为绢云母、石英... 详细信息

歙砚作为我国四大名砚之一,具有很高的经济及艺术价值。为探究歙砚特有纹理的成因和歙砚发墨机理,对江西婺源的歙砚样本进行了光学显微镜、环境扫描电镜、电子探针和能谱等的观察和测试,结果表明歙砚原石的主要组成矿物为绢云母、石英和绿泥石;歙砚的不同纹理形态受控于原生矿物的变质作用程度以及原岩的应力变形作用。结合镜下微观结构和砚锋机制,提出在发墨过程中石英提供了粗磨作用,绢云母和绿泥石提供了细磨作用。通过计算砚锋密度,认为歙砚属于高密度锋一类,从数值的角度定量评估了歙砚的实用属性。再结合自磨刃机理解释了歙砚能够长久维持“滑不拒墨”优异表现的原因。在与其他砚台的比较中,歙砚从观赏性和实用性两方面都表现出了突出的优势。

关键词：歙砚纹理成因发墨机制

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农旅融合与城乡收入差距——以全国休闲农业与乡村旅游示范县创建为例

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农业现代化研究 2024年第2期45卷 257-269页

作者：甘宇王璐重庆工商大学成渝地区双城经济圈建设研究院重庆400067

统筹城乡融合发展是推进乡村振兴的重要抓手之一。本研究基于全国休闲农业与乡村旅游示范县的创建这一准自然实验,利用2006—2021年全国253个地级市的面板数据,采用渐进双重差分模型实证检验了农旅融合政策对城乡收入差距的影响,并运用... 详细信息

统筹城乡融合发展是推进乡村振兴的重要抓手之一。本研究基于全国休闲农业与乡村旅游示范县的创建这一准自然实验,利用2006—2021年全国253个地级市的面板数据,采用渐进双重差分模型实证检验了农旅融合政策对城乡收入差距的影响,并运用中介效应模型与调节效应模型探讨了其内在机制及作用的区域异质性。研究结论表明:农旅融合政策显著促进地级市城乡收入差距的缩小,且在运用合成控制双重差分法等对模型进行有效性检验和工具变量法处理内生性问题后结论依然稳健。机制分析显示,农旅融合政策通过完善交通基础设施建设和促进城乡人员流动来弥合城乡收入差距。进一步,通过调节效应模型发现,因地区间经济发展水平不同,农旅融合政策对城乡收入差距的缩小作用呈现出区域异质性。因此,为有效缩小城乡收入差距,建议持续发挥示范县的带动引领作用,明确非示范县“农业+旅游业”的整体定位和核心竞争力;加大对交通基础设施建设的财政性投入,推动城乡间人员的畅通流动;实施精准的差异化措施,更好发挥农旅融合对城乡收入差距的异质性效应,为推进农业现代化发展与乡村振兴提供新思路。

关键词：农旅融合城乡收入差距渐进双重差分模型准自然实验合成控制双重差分

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A Comprehensive Study on the Consequences of Gap-Graded Sands Considering the Loss of Fine Particles

引用

Journal of Earth Science 2022年

作者： Weiping Liu yu gan yunwei Cui Faming Huang Lina Hu School of Civil Engineering and Architecture Nanchang University

Water and sand leakage disasters are likely to occur during construction in water-rich sand layer areas, resulting in ground collapse. The stress-strain action characteristics of discontinuous graded sand under different internal erosion degrees, and the evolution mechanism of water and sand leakage disasters caused by the internal erosion need to be further explored. Therefore, this paper takes the discontinuous graded sand in a water rich sand layer area in Nanchang City of China as the research object. Considering the influence of different fine particle losses(0, 10%, 20% and 30%) under the internal erosion of sand, the salt solution method is used to realize the specified loss of fine particles in the internal erosion. The stress-strain behavior after the loss of fine particles due to internal erosion is studied by triaxial shear test. Meanwhile, the physical model test and PFC-CFD method are both used to study the evolution rules of water and sand leakage disaster considered the influence of internal erosion degrees. Results show that:(1) under the same confining pressure, the peak failure strength of sand samples decreases along with the increase of fine particle loss.(2) In the water and sand leakage test of saturated sand, a natural filter channel is formed above the observed soil arch. The greater the loss of fine particles, the steeper and wider the collapse settlement area.(3) The relationship between the cumulative amount of water and sand leakage and time is nonlinear. The total mass loss of sand increases along with the increase of internal erosion degree.(4) After the soil arch is formed around the damaged opening, the sand continues to converge above the soil arch under the action of water flow, resulting in the dense convergence of contact force chains.

关键词：

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返乡农民工创业失败经历对其创业绩效的影响

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华侨大学学报（哲学社会科学版） 2024年第3期 88-101页

作者：甘宇罗荟重庆工商大学成渝地区双城经济圈建设研究院重庆400067

探究返乡农民工以往的创业失败经历对当前创业绩效的影响,对促进农户增收,实现乡村振兴具有重要意义。返乡创业失败的农民工再次创业的表现不仅关系到其个人的切身利益,更直接影响当地的创业氛围和乡村振兴战略的顺利推进。基于田野调... 详细信息

探究返乡农民工以往的创业失败经历对当前创业绩效的影响,对促进农户增收,实现乡村振兴具有重要意义。返乡创业失败的农民工再次创业的表现不仅关系到其个人的切身利益,更直接影响当地的创业氛围和乡村振兴战略的顺利推进。基于田野调查获得的数据,运用二元Logistic模型和中介效应模型方法定量分析创业失败经历对西部地区脱贫县返乡农民工再创业绩效的影响,并探讨其作用机制。结果表明:有先前创业失败经历的样本对象占41.62%,创业失败经历明显负向影响其当前的创业绩效;从作用机制来看,风险应对能力在创业失败经历对再创业绩效的影响过程中发挥着中介作用,创业失败经历抑制了再次创业的返乡农民工的风险应对能力,进而引致他们的创业绩效降低。此外,创业失败经历对生存型创业以及非农创业绩效的抑制更为明显。据此,建议构建多元化的创业学习培训体系,充分发挥榜样的帮扶引领作用,为再创业者提供多元化的信息支持,以阻断先前失败创业经历对返乡农民工再创业的消极影响,增强他们的风险应对能力,促进他们再创业绩效的提高。

关键词：返乡农民工创业失败经历创业绩效风险应对能力创业学习

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Prediction of thermoelectric performance for layered IV-V-VI semiconductors by high-throughput ab initio calculations and machine learning

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npj Computational Materials 2021年第1期7卷 1609-1618页

作者： yu gan Guanjie Wang Jian Zhou Zhimei Sun School of Materials Science and Engineering Beihang UniversityBeijing 100191China Center for Integrated Computational Materials Engineering International Research Institute for Multidisciplinary ScienceBeihang UniversityBeijing 100191China

Layered IV-V-VI semiconductors have immense potential for thermoelectric(TE)applications due to their intrinsically ultralow lattice thermal conductivity.However,it is extremely difficult to assess their TE performance via experimental trial-and-error methods.Here,we present a machine-learning-based approach to accelerate the discovery of promising thermoelectric candidates in this chalcogenide family.Based on a dataset generated from high-throughput ab initio calculations,we develop two highly accurateand-efficient neural network models to predict the maximum ZT(ZT_(max))and corresponding doping type,respectively.The top candidate,n-type Pb_(2)Sb_(2)S_(5),is successfully identified,with the ZT_(max) over 1.0 at 650 K,owing to its ultralow thermal conductivity and decent power factor.Besides,we find that n-type Te-based compounds exhibit a combination of high Seebeck coefficient and electrical conductivity,thereby leading to better TE performance under electron doping than hole doping.Whereas p-type TE performance of Se-based semiconductors is superior to n-type,resulting from large Seebeck coefficient induced by high density-ofstates near valence band edges.

关键词： performance doping semiconductors

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冷屏对红外焦平面探测器组件性能的影响

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激光与红外 2024年第6期54卷 924-928页

作者：甘玉梅赵农于小兵中国电子科技集团公司第十一研究所北京100015

分析了国内早期中波320×256红外焦平面探测器组件与国外同类产品在装机性能上的差异,采用三种实验方法检测了国内外探测器组件的光电性能,通过对探测器组件光电转换和结构的分析,确定出杂散光在冷屏内部的反射是导致测试结果差异的原因... 详细信息

分析了国内早期中波320×256红外焦平面探测器组件与国外同类产品在装机性能上的差异,采用三种实验方法检测了国内外探测器组件的光电性能,通过对探测器组件光电转换和结构的分析,确定出杂散光在冷屏内部的反射是导致测试结果差异的原因,冷屏内表面黑化层和结构形式是影响组件实际应用的关键。冷屏结构改进后,有效改善了国内探测器组件的实际应用性能。

关键词：冷屏辐射红外焦平面探测器杂散光

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Morphology and multifractal features of a guyot in specific topographic vicinity in the Caroline Ridge,West Pacific

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Journal of Oceanology and Limnology 2021年第5期39卷 1591-1604页

作者： yu gan Xiaochuan MA Zhendong LUAN Jun YAN CAS Key Laboratory of Marine Geology and Environment Institute ofOceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Geology Pilot National Laboratory for MarineScience and Technology(Qingdao)Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao266071China

Massive seamounts have been surveyed and documented in the last decades.However,the morphologies of seamounts are usually described in qualitative manners,yet few quantitative detections have been carried out.Here,based on the high-re solution multi-beam bathymetric data,we report a recentlysurveyed guy ot on the Caroline Ridge in the West Pacific,and the large-scale volcanic structures and smallscale erosive-depositional landforms in the guyot area have been identified.The multifractal features of the guyot are characterized for the first time by applying multifractal detrended fluctuation analysis on the surveyed bathymetric data.The results indicate that the multifractal spectrum parameters of the seafloor have strong spatial dependency on the fluctuations of local landforms.Both small-and large-scale components contribute to the degree of asymmetry of the multifractal spectrum(B),while the fluctuations of B are mostly attributed to the changes in small-scale roughness.The maximum singularity strength(α0)correlates well with the roughness of large-scale landforms and likely reflects the large-scale topographic irregularity.Comparing to traditional roughness parameters or monofractal exponents,multifractal spectra are able to depict not only the multiscale characteristics of submarine landforms,but also the spatial variations of scaling behaviors.Although more comparative works are required for various seamounts,we hope this study,as a case of quantifying geomorphological characters and multiscale behaviors of seamounts,can encourage further studies on seamounts concerning geomorphological processes,ocean bottom circulations,and seamount ecosystems.

关键词： guyot morphology multifractal detrended fluctuation analysis(MFDFA) Caroline Ridge West Pacific Ocean

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个体化进程中智能手机与农村留守儿童的新型社会化

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新闻大学 2024年第2期214卷 44-56,118,119页

作者：殷文李思怡甘雨柔南京林业大学人文社会科学学院江苏南京210037 南京林业大学国家林草局林业遗产与森林环境史研究中心江苏南京210037

研究以留守儿童的新媒介使用为研究对象,将一起玩手机视为儿童社会化过程中与同辈群体的“嬉戏”(play)方式,致力于讨论媒介与同辈群体这一社会化机制的关系。研究发现,“一起玩手机”对留守儿童同辈群体身份认同和社会身份认同起关键... 详细信息

研究以留守儿童的新媒介使用为研究对象,将一起玩手机视为儿童社会化过程中与同辈群体的“嬉戏”(play)方式,致力于讨论媒介与同辈群体这一社会化机制的关系。研究发现,“一起玩手机”对留守儿童同辈群体身份认同和社会身份认同起关键性作用,是他们的同辈群体社会化过程(媒介嬉戏),同时也是他们抗争社会化过程中所产生的身份轻视、建构个体尊严的个体化过程(尊严游戏)。

关键词：留守儿童同辈群体媒介嬉戏尊严游戏

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