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浅埋偏压隧道在变坡面下围岩压力计算分析

中外公路 2024年第3期44卷 211-219页

作者：白岩乔婷婷宁晓骏刘国坤昆明理工大学建筑工程学院云南昆明650500 山西省公路局长治分局山西长治046000 湖南工程学院建筑工程学院湖南湘潭411100

为研究浅埋偏压隧道在变坡面下合理的围岩压力的计算方法,该文建立浅埋偏压隧道在变坡面下围岩压力计算模型,运用极限平衡原理推导围岩压力计算公式。引入中间变量β′,将其作为选取变坡条件下的偏压隧道围岩压力计算方法的依据,并将该... 详细信息

为研究浅埋偏压隧道在变坡面下合理的围岩压力的计算方法,该文建立浅埋偏压隧道在变坡面下围岩压力计算模型,运用极限平衡原理推导围岩压力计算公式。引入中间变量β′,将其作为选取变坡条件下的偏压隧道围岩压力计算方法的依据,并将该文推导公式对比规范公式计算值与隧道围岩压力实测值进行验证。研究结果显示:经对比验证,该文公式具有合理性与实用性。且由计算公式分析可得,当自然坡度角增大,水平侧压力系数λ_(1)随之增大;当黏聚力增大,水平侧压力系数λ_(2)呈先增大后减小趋势;当变坡角度增大,水平侧压力系数λ_(2)将会减小。研究表明:偏压隧道存在变坡会影响隧道变坡段一侧的围岩压力,因此利用该文变坡条件的围岩压力计算公式是必要的。

关键词：隧道工程偏压隧道围岩压力极限平衡原理

Carbon dioxide capture using polyethylenimine-loaded mesoporous carbons

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Journal of Environmental Sciences 2013年第1期25卷 124-132页

作者： Jitong Wang Huichao Chen Huanhuan Zhou xiaojun Liu Wenming qiao Donghui Long Licheng Ling State Key Laboratory of Chemical Engineering East China University of Science and Technology

A high efficiency sorbent for CO2 capture was developed by loading polyethylenimine （PEI） on mesoporous carbons which possessed well-developed mesoporous structures and large pore volume. The physicochemical properties of the sorbent were characterized by N2 adsorption/desorption, scanning electron microscopy （SEM）, thermal gravimetric analysis （TG） and Fourier transform infrared spectroscopy （FT-IR） techniques followed by testing for CO2 capture. Factors that affected the sorption capacity of the sorbent were studied. The sorbent exhibited extraordinary capture capacity with CO2 concentration ranging from 5% to 80%. The optimal PEI loading was determined to be 65 wt.% with a CO2 sorption capacity of 4.82 mmol-CO2/g-sorbent in 15% CO2/N2 at 75℃, owing to low mass-transfer resistance and a high utilization ratio of the amine compound （63%）. Moisture had a promoting effect on the sorption separation of CO2. In addition, the developed sorbent could be regenerated easily at 100℃, and it exhibited excellent regenerability and stability. These results indicate that this PEI-loaded mesoporous carbon sorbent should have a good potential for CO2 capture in the future.

关键词： carbon dioxide capture polyethylenimine mesoporous carbon amine utilization ratio

Geochemical characteristics of Oligocene-Miocene sediments from the deepwater area of the northern South China Sea and their provenance implications

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Acta Oceanologica Sinica 2018年第2期37卷 35-43页

作者： CHEN Shuhui qiao Peijun ZHANG Houhe XIE xiaojun CUI Yuchi SHAO Lei State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China Shenzhen Branch of China National Offshore Oil Corporation Guangzhou 510240 China China National Offshore Oil Corporation Research Institute Beijing 100027 China

Geochemical and detrital zircon U-Pb dating data for drilled sediments from the Baiyun deepwater area of the northern South China Sea demonstrate a change of sedimentary sources from the Oligocene to the *** ages of the pre-rift Eocene sequences are dominated by Yanshanian ages with various peak values（110–115 Ma for U1435 and L21; 150 Ma for H1）, indicating local sediment supply from the pre-existing Mesozoic magmatic belt. For the Oligocene sediments in the northern part of the basin, the rare earth elements show different distribution characteristics, indicating sediment supply from the paleo-Zhujiang River（Pearl River）, as also confirmed by the multimodal zircon age spectra of the Lower Oligocene strata in Well X28. By contrast, a positive Eu anomaly characterizes sediments from the western and southern parts of the basin, indicating potential provenances from intermediate to basic volcanic rock materials. The Baiyun Movement at the end of the Oligocene contributed to a large-scale subsidence in the deepwater area and also a northward retreat of continental shelf break, leading to deepening depositional environment in the basin. As a result, all the detrital zircon ages of the Upper Oligocene strata from Wells X28, L13, and L21 share a similar distribution, implying the possible control of a common source like the Zhujiang River. During the Miocene, whereas sediments in the northern area were mainly sourced from the Zhujiang River Delta, and those in the southern deepwater area continued to be affected by basic volcanic activities, the Dongsha Uplift could have contributed as the main source to the eastern area.

关键词： geochemistry zircon U-Pb age provenance South China Sea Baiyun deepwater area

Model eyes with curved multilayer structure for the axial resolution evaluation of an ophthalmic optical coherence tomography device

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Journal of Innovative Optical Health Sciences 2018年第3期11卷 65-71页

作者： Zhenggang Cao Zengqian Ding Zhixiong Hu Wen qiao Wenli Liu xiaojun Chen National Institute of Metrology Division of Medical and Biological MeasurementsBeijing 100029P.R.China Optoelectronics and Energy&Collaborative Innovation Center of Suzhou Nano Science and Technology College of Physics Soochow UniversitySuzhou 215006P.R.China Key Laboratory of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Laboratory of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215006P.R.China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240P.R.China

Optical coherence tomography(OCT)has been widely applied to the diagnosis of eye diseasesduring the past two ***,valid evaluation methods are stil not available for theclinical OCT *** order to assess the axial resolution of the OCT system,standard modeleyes with micro-scale multilayer structure have been designed and manufactured in this *** a natural human eye,proper Titanium dioxide(TiO_(2))materials of particles withdifferent concentrations were selected by testing the scattering coefficient of PDMS *** artificial retinas with multilayer films were fabricated with the thicknesses from 9.5 to 30 micrometers using spin coating technology,Subsequently,standard OCT model eyes were ac-complished by embedding the retina phantoms into the artificial frames of *** ease ofmeasurement processing,a series of model eyes were prepared,and each contained flms withthree kinds of *** the traceability and accuracy of the key parameters of the standard model eyes,the thicknesses of multilayer structures were verfed using ThicknessMonitoring *** the experiment with three different OCT devices,it demonstratedthe model eyes fabricated in this study can provide an effective evaluation method for the axialresolution of an ophthalmic OCT device.

关键词： Optical coherence tomography metrology optical standards and testing spin coating

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土壤三参数测量方法研究

现代科学仪器 2007年第5期24卷 101-104页

作者：赵春江王成侯瑞锋乔晓军徐志龙国家农业信息化工程技术研究中心北京100097

土壤参数可以反映出土壤自身的品质状况以及未来的变化发展趋势,其变化是影响作物生长发育的主要因素。文中详细介绍土壤的三个重要参数:土壤温度、含水量和电导率的测量方法,分析比较了不同方法的特点。最后给出TDR方法进行土壤三参数... 详细信息

土壤参数可以反映出土壤自身的品质状况以及未来的变化发展趋势,其变化是影响作物生长发育的主要因素。文中详细介绍土壤的三个重要参数:土壤温度、含水量和电导率的测量方法,分析比较了不同方法的特点。最后给出TDR方法进行土壤三参数测量的基本原理和算法。

关键词：温度含水量电导率 TDR

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我国光伏设施园艺发展现状及趋势

农业工程 2017年第6期7卷 52-56页

作者：尚超马长莲孙维拓徐凡乔晓军郭文忠北京农业智能装备技术研究中心北京100097 北京农学院植物科技学院北京102206 青海省海东市互助农业示范园区管理委员会西宁810599

光伏发电作为太阳能利用的主要形式之一,在应对全球气候变化、能源转型方面都发挥着重要作用。随着国家对新能源的重视和扶持,光伏应用市场逐渐增大。但是可用于从事光伏发电的荒山荒地越来越少,远不能满足市场需求,光伏农业开创性地将... 详细信息

光伏发电作为太阳能利用的主要形式之一,在应对全球气候变化、能源转型方面都发挥着重要作用。随着国家对新能源的重视和扶持,光伏应用市场逐渐增大。但是可用于从事光伏发电的荒山荒地越来越少,远不能满足市场需求,光伏农业开创性地将光伏产品与农业种植结合,为光伏产业发展提供了新的平台。近年来光伏设施园艺产业发展迅速,但也存在着诸多争议和问题。综述了国内外光伏温室发展建造的研究进展,重点分析了光伏温室的构造特点、光伏板类型、室内光热环境特征及经济效益等,探讨了光伏设施园艺产业优势与不足,并针对存在问题提出了发展建议,对光伏设施园艺产业的正确发展提供参考。

关键词：光伏设施园艺光伏温室

Paternal transgenerational nutritional epigenetic effect:A new insight into nutritional manipulation to reduce the use of antibiotics in animal feeding

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Animal Nutrition 2022年第4期11卷 142-151页

作者： Xinyi Li Mengya Wang Shimin Liu Xiaodong Chen Yu qiao xiaojun Yang Junhu Yao Shengru Wu College of Animal Science and Technology Northwest A&F UniversityYanglingShaanxi 712100China Institute of Agriculture University of Western AustraliaCrawleyWA 6009Australia Department of Medicine Karolinska InstitutetSolnaStockholm 17165Sweden Department of Animal Engineering Yangling Vocational and Technical CollegeYanglingShaanxi 712100China

The use of antibiotics in animal feeding has been banned in many countries because of increasing concerns about the development of bacterial resistance to antibiotics and potential issues on food *** for antibiotic substitutes is *** transgenerational epigenetic technology to animal production could be an *** environmental changes can be transferred to memorylike responses in the offspring through epigenetic mechanisms without changing the DNA *** this paper,we reviewed those nutrients and non-nutritional additives that have transgenerational epigenetic effects,including some amino acids,vitamins,and *** paternal transgenerational nutritional epigenetic regulation was particularly focused on mechanism of the substantial contribution of male stud animals to the animal *** illustrated the effects of paternal transgenerational epigenetics on the metabolism and immunity in farming animals and proposed strategies to modulate male breeding livestock or poultry.

关键词： Growth Nutrition Immune Transgenerational epigenetic Antibiotic replacement

Exceptional thermal stability and enhanced hardness in a nanostructured Mg-Gd-Y-Zn-Zr alloy processed by high pressure torsion

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Journal of Magnesium and Alloys 2023年第12期11卷 4589-4602页

作者： Wanting Sun Yang He Xiaoguang qiao xiaojun Zhao Houwen Chen Nong Gao Marco J.Starink Mingyi Zheng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Materials Research Group School of EngineeringUniversity of SouthamptonSouthampton SO171BJUnited Kingdom Center for Composite Materials and Structures Harbin Institute of TechnologyHarbin 150001China Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHung HomHong KongChina

A Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr(wt.%) alloy is processed by solution treatment and high pressure torsion(HPT) at room temperature to produce a nanostructured light material with high hardness. The stability of this alloy is subsequently tested through isochronal annealing for 0.5 h at 373 K to 673 K. The results reveal a thermal stability that is vastly superior to that of conventional Mg-based alloys processed by severe plastic deformation: the grain size remains at around 50 nm on heating to 573 K, and as the temperature is increased to 673 K,grain growth is restricted to within 500 nm. The stability of grain refinement of the present alloy/processing combination allowing grain size to be limited to 55 nm after exposure at 573 K, appears to be nearly one order of magnitude better than for the other SPD processed Mg-RE type alloys, and 2 orders of magnitude better than those of SPD processed RE-free Mg alloys. This superior thermal stability is attributed to formation of co-clusters near and segregation at grain boundaries, which cause a thermodynamic stabilization of grain size, as well as formation of β-Mg_(5)RE equilibrium phase at grain boundaries, which impede grain growth by the Zener pinning effect. The hardness of the nanostructured Mg-Gd-Y-Zn-Zr alloy increases with increasing annealing temperature up to 573 K, which is quite different from the other SPD-processed Mg-based alloys. The high hardness of 136 HV after annealing at 573 K is mainly due to solute segregation and solute clustering at or near grain boundaries.

关键词： Mg-RE alloy High pressure torsion Thermal stability Grain growth Solute segregation Phase transformation

Interfacial electronic interaction enabling exposed Pt(110)facets with high specific activity in hydrogen evolution reaction

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Nano Research 2023年第1期16卷 174-180页

作者： Sicong qiao Qun He Quan Zhou Yuzhu Zhou Wenjie Xu Hongwei Shou Yuyang Cao Shuangming Chen xiaojun Wu Li Song National Synchrotron Radiation Laboratory CAS Center for Excellence in NanoscienceUniversity of Science and Technology of ChinaHefei 230026China Hefei National Laboratory for Physical Science at the Microscale Collaborative Innovation of Center of Chemistry for Energy Materials(iChEM)School of Chemistry and Materials SciencesUniversity of Science and Technology of ChinaHefei 230026China

To achieve a complete industrial chain of hydrogen energy,the development of efficient electrocatalysts for hydrogen evolution reaction(HER)is of great ***,a nickel nitride supported platinum(Pt)catalyst with highly exposed Pt(110)facets(Pt_((110))-Ni_(3)N)is obtained for catalyzing *** X-ray spectra and density functional theory studies demonstrate that the interfacial electronic interaction between Pt and Ni3N support can promote the hydrogen evolution on Pt(110)facets by weakening hydrogen *** a result,the Pt_((110))-Ni_(3)N catalyst delivers an obviously higher specific activity than commercial 20 wt.%Pt/C in acidic *** work suggests that the suitable interface modulation may play a vital role in rationally designing advanced electrocatalysts.

关键词： Interfacial electronic interaction hydrogen evolution reaction X-ray spectroscopy Pt(110)facets density functional theory