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Development of a preliminary slope stability calculation method based on internal horizontal displacements

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Journal of Mountain Science 2018年第5期15卷 1129-1136页

作者： pei Hua-fu ZHANG si-qi BORANA Lalit YUAN Bing Department of Geotechnical Engineering Dalian University of Technology Dalian 116024 China Department of Civil Engineering Indian Institute of Technology Indore Indore 453552 India. Shenzhen Graduate school Harbin Institute of Technology Shenzhen 518055 China

This paper proposes a horizontal displacement-based approach to determine the potential slip surface of the slope. Firstly, a group of in-situ inclinometers with an appropriate spacing in the horizontal direction is located in the model *** equation of horizontal displacement with time for each in-situ inclinometer is fitted during the whole simulation process. Furthermore, the intersection of each inclinometer with potential slip surface is determined by using an optimization model. The slip surface can be obtained by using least square fitting method. Finally, the feasibility and accuracy of the method are validated by a series of numerical simulations. It is noted that the optimization model taking the maximum value of displacement increment gradient as an objective has higher accuracy when compared with other optimization models. This method employed in this study provides a preliminary approach to determine the real-time slope stability based on displacement, which can also be measured by using conventional instruments on site.

关键词： Slip surface Slope stability analysis Optimization model Numerical simulation Displacement.

Pt overlayer for direct oxidation of CH_(4)to CH_(3)OH

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Chinese Chemical Letters 2023年第11期34卷 280-284页

作者： Haoyu Li Wei pei Xiaowei Yang si Zhou Jijun Zhao Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Dalian University of Technology)Ministry of EducationDalian 116024China College of Physics Science and Technology Yangzhou UniversityYangzhou 225009China

Highly selective conversion of methane(CH_(4))to methanol(CH_(3)OH)is an emerging attractive but challenging process for future development of hydrogen economy,which requires efficient ***,we systematically explore the catalytic properties of Pt(111)overlayer on transition metal oxides(TMOs)for CH_(4) conversion by first principles *** Pt(111)monolayer supported by Ce-terminated CeO_(2)(111)substrate exhibits high activity and selectivity for CH_(4) conversion to CH_(3)OH,with the kinetic barrier of rate-limiting step of 1.05 ***,the surface activity of Pt overlayer is governed by its d-band center relative to the energy of bonding states of adsorbed molecules,which in turn depends on the number of charge transfer between Pt(111)monolayer and underlying TMOs *** results provide useful insights in the design of metal overlayers as catalysts with high-ultra performance and atomic utilization.

关键词： CH_(4)conversion Pt(111)overlayer d-band center

Enhancement of Flow Boiling Heat Transfer with Surfactant

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Journal of Central South University 2000年第4期12卷 219-222页

作者： QIU Yun-ren CHEN Wei-ping si Qin College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China Editorial Office of Journal of Central South University of Technology Central South UniversityChangsha 410083China College of Chemical Engineering Tianjin UniversityTianjin 300072China

The surfactant additive octadecylamine (ODA) was used to enhance the flow boiling heat transfer of water in vertical copper tube, and the effects of the aqueous solution properties, mass fraction of ODA, mass flux and heat flux etc. on flow boiling heat transfer were investigated. In order to analyze the mechanism of enhancement on boiling heat transfer with ODA, the copper surface was detected by XPS, and the diagram of binding energy was obtained. The results show that ODA can be adsorbed on the surface of the copper wall, and affects the properties of the heating surfaces and enhances the flow boiling heat transfer of water. Only in low heat flux and in a suitable range of concentration, can ODA aqueous solution enhance flow boiling heat transfer, and the suitable mass fraction of ODA is in the range of 1×10 -5 5×10 -5 . In addition, compared with water, ODA aqueous solution does not increase the flow drag under the same experimental conditions.

关键词： flow boiling heat transfer flow drag enhancement additive

Nanotribological properties and scratch resistance of MoS_(2)bilayerona siO_(2)/si substrate

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Friction 2023年第1期11卷 154-164页

作者： si-hwan KIM Hyo-sok AHN Department of Transdisciplinary Studies Seoul National UniversitySeoul 08826Republic of Korea Department of Manufacturing Systems and Design Engineering Seoul National University of Science and TechnologySeoul 08826 Republic of Korea

The tribological properties and scratch resistance of MoS_(2)bilayer deposited on siO_(2)/si substrates prepared via chemical vapor deposition are *** force microscopy(FFM)is employed to investigate the friction and wear properties of the MoS_(2)bilayer at the nanoscale by applying a normal load ranging from 200 to 1,000 *** resistance is measured using the scratch mode in FFM based on a linearly increasing load from 100 to 1,000 *** probe force microscopy(KPFM)is performed to locally measure the surface potential in the tested surface to qualitatively measure the wear/removal of Mos,layers and identify critical loads associated with the individual failures of the top and bottom *** analysis of the contact potential difference values as well as that of KPFM,friction,and height images show that the wear/removal of the top and bottom layers in the MoS_(2)bilayer system occurred *** FFM and KPFM results show that the top MoS_(2)layer begins to degrade at the end of the low friction stage,followed by the bottom layer,thereby resulting in a transitional friction stage owing to the direct contact between the diamond tip and siO_(2)*** the stable third stage,the transfer of lubricious MoS_(2)debris to the tip apex results in contact between the MoS_(2)-transferred tip and siO_(2).Nanoscratch test results show two ranges of critical loads,which correspond to the sequential removal of the top and bottom layers.

关键词： chemical vapor deposition(CVD)-grown MoS,bilayer friction force microscopy(FFM) nanoscratch test Kelvin probe force microscopy(KPFM) scratch resistance

High-entropy design boosts dielectric energy storage

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Rare Metals 2024年第8期43卷 4013-4015页

作者： Qiu-Ying Xia He Zhu si Lan Yang ren Herbert Gleiter Institute of Nanoscience School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China Department of Physics City University of Hong KongHong Kong999077China

Dielectric capacitors are vital for advanced electronic and electrical power systems due to their impressive power density and ***,a persistent challenge has been enhancing their energy densities while maintaining high *** in Science,a novel high-entropy design for relaxor ferroelectric materials has been proposed,promising significant improvements in both energy density and efficiency for multilayer dielectric ceramic *** the crucial role of high-entropy design in energy storage materials and devices,this highlight focuses on interpreting the progress and significance of this innovative work.

关键词： ceramic dielectric energy

Down-regulation of Risa improves podocyte injury by enhancing autophagy in diabetic nephropathy

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Military Medical Research 2023年第1期10卷 32-44页

作者： pei-pei Su Dong-Wei Liu si-Jie Zhou Hang Chen Xian-Ming Wu Zhang-Suo Liu Department of Nephrology the First Affiliated Hospital of Zhengzhou UniversityResearch Institutes of NephropathyZhengzhou UniversityZhengzhou 450052China Department of Nephrology and Rheumatology the Third People’s Hospital of ZhengzhouZhengzhou 450002China Henan Province Research Center for Kidney Disease Zhengzhou 450052China Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province Zhengzhou 450002China

Background: LncRNA AK044604(regulator of insulin sensitivity and autophagy, Risa) and autophagy-related factors sirt1 and GSK3β play important roles in diabetic nephropathy(DN). In this study, we sought to explore the effect of Risa on sirt1/GSK3β-induced podocyte ***: Diabetic db/db mice received Risa-inhibition adeno-associated virus(AAV) via tail vein injection, and intraperitoneal injection of lithium chloride(LiCl). Blood, urine, and kidney tissue samples were collected and analyzed at different time points. Immortalized mouse podocyte cells(MPCs) were cultured and treated with Risa-inhibition lentivirus(LV), EX-527, and LiCl. MPCs were collected under different stimulations as noted. The effects of Risa on podocyte autophagy were examined by qRT-PCR, Western blotting analysis, transmission electron microscopy,Periodic Acid-Schiff staining, and immunofluorescence ***: Risa and activated GSK3β were overexpressed, but sirt1 was downregulated in DN mice and high glucosetreated MPCs(Psis. Risa overexpression attenuated sirt1-mediated downstream autophagy levels and aggravated podocyte injury by inhibiting the expression of sirt1(Psion enhanced sirt1-induced autophagy and attenuated podocyte injury, which could be abrogated by EX-527(Psion aggravated podocyte injury by decreasing ***: Risa could inhibit autophagy by regulating the sirt1/GSK3β axis, thereby aggravating podocyte injury in DN. Risa may serve as a therapeutic target for the treatment of DN.

关键词： Diabetic nephropathy LncRNA AK044604/sirt1/GSK3β Autophagy

Toward an Optimum Design of an Amorphous silicon Photovoltaic/Thermal System:simulation and Experiments

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Journal of Thermal Science 2023年第3期32卷 947-964页

作者： ren Xiao LI Jing LIU Weixin ZHU Chuanyong pei Gang GONG Liang College of New Energy China University of Petroleum(East China)Qingdao 266580China Research Center for Sustainable Energy Technologies Energy and Environment InstituteUniversity of HullHU67RXUK Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230026China

Amorphous silicon photovoltaic/thermal(a-si-PV/T)technology is promising due to the low power temperature coefficient,thin-film property,thermal annealing effect of the solar cells,and high conversion efficiency in *** design of a-si-PV/T system is influenced by a number of thermodynamic,structural,and external *** analysis is useful for a good design of the system.A dynamic distributed parameter model is built and verified in this *** tests are carried *** impacts of operating temperature,mass flow rate,cover ratio of solar cells,heat transfer area,and frame shadow ratio on its performance are theoretically and experimentally *** results indicate that seven or eight copper tubes are suitable to achieve a high overall efficiency of the a-si-PV/T *** frame and tilt angle shall avoid a shadow ratio of more than 8.3%during *** difference between power outputs at operating temperatures of 35℃and55℃in the first month is about 0.21%while it drops to less than 0.1%in the twelfth *** with conventional PVT systems,the a-si-PV/T system benefits from a higher design temperature with a minor efficiency decrement.

关键词： amorphous silicon cell photovoltaic thermal system parametric analysis distributed parameter model frame shadow

Prognostics based on the generalized diffusion process with parameters updated by a sequential Bayesian method

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Science China(Information Sciences) 2022年第6期65卷 172-188页

作者： Hong pei Xiaosheng si Changhua HU Jianxun ZHANG Dangbo DU Zhenan PANG Shengfei ZHANG School of Missile Engineering Rocket Force University of Engineering School of Mechanical Engineering Xi'an Jiaotong University

The realistic degradation process for the engineering equipment is generally stochastic and complicated owing to the uncertain operational condition and multiple functional loading, exhibiting the absolute nonlinear distinction. Such a nonlinear degradation process is widely modeled as a generalized diffusion process. When utilizing the generalized diffusion process-based model, certain model parameters are considered as the random variables to characterize the unit-to-unit discrepancies. Hence, the estimation of these kinds of parameters usually resorts to the Bayesian method. However, owing to the complex pattern of the model parameters in the generalized diffusion process, computing the Bayesian updated parameters requires plenty of repeated calculation and integration operations once the new degradation monitoring information is available. This will inevitably lower the computing efficiency and real-time performance. Toward this end, this paper presents an adaptive prognostic method based on the generalized diffusion process to determine the remaining useful life(RUL) of degraded equipment. First, a generalized diffusion process-based degradation modeling framework is constructed to describe the health performance of stochastic degraded equipment under complex conditions. Then, we utilize the maximum likelihood estimation(MLE) method to estimate the initial model parameters by analyzing the historical degradation information. Furthermore, a sequential Bayesian method is proposed to recursively update the stochastic model parameters in the generalized diffusion process for particular equipment in service. Unlike the existing studies utilizing the Bayesian method,the primary contrast in the presented method lies in that there is no need to implement the calculation process with complicated integration repeatedly utilizing the whole degradation information obtained before the current time. Particularly, the current measured information is incorporated into the esti

关键词： generalized diffusion process stochastic model parameters remaining useful life maximum likelihood estimation sequential Bayesian methods

基于光谱技术的典型互花米草入侵湿地土壤属性预测研究

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光谱学与光谱分析 2025年第1期45卷 197-203页

作者：陈旭曹思珩杨仁敏陈秋宇李建国徐璐 4 江苏师范大学地理测绘与城乡规划学院地理信息科学系江苏徐州221116

为了高效监测互花米草入侵海岸带湿地生态系统的土壤属性变化,选取江苏省盐城湿地珍禽国家级自然保护区的一处典型互花米草入侵湿地作为研究区,利用随机分层采样方法选取15个样点,在3个深度(0~30、30~60、60~100 cm)共采集45个土壤样品... 详细信息

为了高效监测互花米草入侵海岸带湿地生态系统的土壤属性变化,选取江苏省盐城湿地珍禽国家级自然保护区的一处典型互花米草入侵湿地作为研究区,利用随机分层采样方法选取15个样点,在3个深度(0~30、30~60、60~100 cm)共采集45个土壤样品,测定了土壤可见光-近红外反射光谱和10种土壤理化属性,研究了偏最小二乘和随机森林两种方法的预测能力,分析了不同光谱变换形式对预测精度的影响,探讨了入侵年限和土壤深度作为辅助预测变量的潜力。结果表明:(1)可见光-近红外光谱技术可以较好地预测有机碳、无机碳、全氮、含水量、pH、容重、盐分和黏粒等属性;(2)偏最小二乘回归法比随机森林法更适合监测互花米草入侵湿地的关键土壤理化属性,利用偏最小二乘法对土壤属性建立的预测模型精度(R^(2))在0.341~0.979之间,随机森林方法对土壤属性建立的预测模型精度(R^(2))最高为0.722;(3)基于原始光谱可以获得土壤全氮的最优预测模型(R^(2)为0.769,RMSE为0.091 g·kg^(-1)),而其他土壤属性的最优模型多是基于微分变换或倒数变换建立的模型,微分变换和倒数变换可以有效地提高模型预测精度;(4)模型预测精度在加入入侵年限和土壤深度两个变量后总体上有所提高,其中有机碳、全氮、盐分、pH和容重等属性的预测精度对这两个变量更为敏感,土壤有机碳最优模型的精度(R^(2))从0.794提高到0.806,pH最优模型的精度(R^(2))从0.838提升至0.884,盐分最优模型的精度(R^(2))从0.978提升至0.997。综上所述,可见光-近红外光谱技术在互花米草入侵湿地关键土壤理化属性预测方面具有明显的优越性,通过适当的光谱变换、变量筛选、模型选择等方面可以实现互花米草入侵湿地土壤变化的快速监测。

关键词：互花米草入侵可见光-近红外光谱土壤监测偏最小二乘法随机森林光谱变换