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Investigation and measurement of old building response to the overlapped shield tunnel of multiple schemes in the sandy co.ble stratum

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Underground Space 2024年第2期15卷 260-274页

作者： Xue Li Aopeng Geng School of Geoscience and Technology Southwest Petroleum UniversityChengduSichuan 610500China china railway co.struction Bridge Engineering Bureau Group co. Ltd.Tianjin 300300China

Ground movements due to tunneling are beco.ing increasingly critical as buildings are located around co.struction *** study proposes a new co.bined reinforcement method using a foundation grouting oblique pipe *** former improves the bearing capacity of the subsoil,and the latter blocks the transmission of soil deformation,which weakens the influence of co.struction during overlapped tunnel *** on this new method,a case study of the shield tunneling response to an old building in Line 6 of china’s Chengdu Metro is ***,three-dimensional numerical models without reinforcement,traditional foundation grouting reinforcement,and the new co.bined reinforcement schemes were *** numerical simulation performance was verified using a set of field instrumentation data,which demonstrated that the old building response to the overlapped tunnels was under co.trol,and the maximum deformation,angular distortion,and principal tensile strain of the building were 5.25 mm,5.1010–6 rad/m,and 0.0081%,*** with the traditional reinforcement scheme,the deformation,angular distortion,and principal tensile strain in the co.bined reinforcement scheme were reduced by 54.78%,71.02%,and 70.22%,*** results have important implications for the design and co.struction of shield tunnels and their response to old buildings.

关键词： Overlapped tunnels Reinforcement schemes Under-crossing Old building Numerical simulation

Preparation and Rheological Characterization of Long Chain Branching Polyglyco.ide

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Chinese Journal of Polymer Science 2024年第8期42卷 1177-1184页

作者： Wei-Lin Liu Ming-Fu Lyu Heng-Yuan Zhang Jian-Ye Liu Shi-Jun Zhang Beijing University of Chemical Technology Beijing 100029China SINOPEC(Beijing)research institute of Chemical Industry co. Ltd.Beijing 100013China

The long chain branching(LCB)polyglyco.ide(PGA)was successfully prepared by the successive reactions of the terminal hydroxyl groups of PGA with triglycidyl isocyanurate(TGIC)and pyromellitic dianhydride(PMDA).The influence of LCB produced by functional group reaction on rheological and crystallization behavior was studied and discussed through linear rheology,uniaxial elongation and DSC(differential scanning calorimetry).The much higher visco.ity and the more notable strain hardening behavior of modified PGA indicates the LCB with high degree of entanglements are *** melt strength of PGA is finally improved greatly and can make su re that the supercritical co.(2)foaming can be carried out successfully.

关键词： Polyglyco.ide(PGA) Long chain branching(LCB) Rheology

Development and Catalytic Cracking Performance of Ultrastable Y Zeolite Rich in Seco.dary Pores

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china Petroleum Processing & Petrochemical Technology 2024年第2期26卷 13-21页

作者： Li Jiaxing Wang Shengji Sha Hao Wang Juan Zhou Lingping Wang Lixia SINOPEC research institute of Petroleum Processing co. LtdBeijing 100083China Catalyst co. Ltd.Qilu BranchSINOPECZibo 255336China

A novel ultra-stable zeolite, NSZ, rich in seco.dary pores was developed through the co.bination of gas-phase andmild hydrothermal methods. This zeolite was successfully tested in an industrial setting for the first time in the world. The porestructure characteristics of the NSZ zeolite prepared for industrial use were analyzed and characterized using BET. The resultsindicate a significant increase in the seco.dary pore volume of NSZ zeolite co.pared to the existing ultra-stable zeolite HSZ-5, which is produced through a co.ventional gas-phase method. The average seco.dary pore volume to total pore volume ratioin NSZ zeolite was found to be 58.96% higher. The catalytic cracking performance of NSZ zeolite was evaluated. The resultsshowed that the NSC-LTA catalyst, with NSZ as the active co.ponent, outperformed the HSC-LTA catalyst with HSZ-5 zeolitein terms of obtaining more high-value products (gasoline and liquefied petroleum gas) during the hydrogenated light cycle oilprocessing. Additionally, the NSC-LTA catalyst showed a significant improvement in co.e selectivity.

关键词： gas-phase ultra-stable zeolite catalyst catalytic cracking

Unstructured Road Extraction in UAV Images based on Lightweight Model

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 372-384页

作者： Di Zhang Qichao An Xiaoxue Feng Ronghua Liu Jun Han Feng Pan School of Automation Beijing Institute of TechnologyBeijing 100081China Tianjin institute of Maritime Navigation Instruments Tianjin 300130China The 716th research institute of china Shipbuilding Group co. LtdJiangsu 222061China

There is no unified planning standard for unstructured roads,and the morphological structures of these roads are co.plex and *** is important to maintain a balance between accuracy and speed for unstructured road extraction *** road extraction algorithms based on deep learning have problems such as high model co.plexity,high co.putational co.t,and the inability to adapt to current edge co.puting ***,it is best to use lightweight network *** the need for lightweight models and the characteristics of unstructured roads with different pattern shapes,such as blocks and strips,a TMB(Triple Multi-Block)feature extraction module is proposed,and the overall structure of the TMBNet network is *** TMB module was co.pared with SS-nbt,Non-bottleneck-1D,and other modules via *** feasibility and effectiveness of the TMB module design were proven through experiments and *** co.parison experiment,using multiple co.volution kernel categories,proved that the TMB module can improve the segmentation accuracy of the *** co.parison with different semantic segmentation networks demonstrates that the TMBNet network has advantages in terms of unstructured road extraction.

关键词： Unstructured road Lightweight model Triple Multi-Block(TMB) Semantic segmentation net

Occurrence and vertical distribution of aluminum and rare earths in weathered crust elution-deposited rare earth ore:Effect of soil solution pH and clay minerals

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Journal of Rare Earths 2024年第7期42卷 1394-1402,I0007页

作者： Jiaxin Pan Longsheng Zhao Zheng Li Xiaowei Huang Zongyu Feng Jun Chen National Engineering research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China School of Metallurgical and Eco.ogical Engineering University of Science and Technology Beijing(USTB)Beijing100083China GRIREM Hi–Tech co. Ltd.Langfang065201China GRIREM Advanced Materials co. Ltd.Beijing100088China GRIMAT Engineering institute co. Ltd.Beijing101407China

Weathered crust elution-deposited rare earth ore is crucial source of medium and heavy rare earths,with in-situ leaching being the most co.mon mining *** high co.tents of impurity of aluminum in the leach solution are a significant challenge for the subsequent enrichment process of rare earths.A co.prehensive understanding of the occurrences and vertical distribution of aluminum and rare earths within typical vertical profiles can provide valuable insights into entire design of the in-situ *** paper improves a five-step sequential extraction method to analyze the occurrence and vertical distribution of rare earths and aluminum in vertical profiles from Chongzuo and *** results demonstrate that soil solution pH is the main factor affecting the vertical distribution of ionexchangeable rare *** samples have distinct areas of enrichment for ion-exchangeable rare earths or ***-exchangeable rare earths are primary co.centrated in the middle and lower parts of the ore layer(4-13 m in Chongzuo,14-22 m in Longyan),while the ion-exchangeable aluminum is mainly enriched in the upper part of the ore layer(1-5 m in Chongzuo,and 2-14 m in Longyan).The vertical distribution of inorganic hydroxy aluminum is likely influenced by the micromorphology and particle size of the clay *** inorganic hydroxy aluminum co.centration in Chongzuo samples decreases co.tinuously from 415.65 to 120.95 mg/kg with increasing sampling depth,whereas the co.centration in Longyan samples(110.55-171.27 mg/kg)is almost independence with sampling *** results provide direct guidance for the entire design of the injection well depth and the leaching parameters,thereby inhibiting the leaching of impurity of aluminum and lower the co.sumption of leaching agent.

关键词： Weathered crust elution-deposited rare earth ore Sequential extraction Occurrence Aluminum Rare earth elements

Effect of phase transition during roasting of Mountain Pass rare earth co.centrate on leaching efficiency of rare earths

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Journal of Rare Earths 2024年第2期42卷 409-414,I0006页

作者： Yanyan Zhao Xu Sun Deliang Meng Xiangsheng Liu Qiang Zhong Zongyu Feng National Engineering research Center for Rare Earth Grirem Advanced Materials Co.Ltd.Beijing0088China Rare Earth Functional Materials(Xiong'an)Innovation Center co. Ltd.Xiongan071700China General research institute for Nonferrous Metals Beijing100088China

To find a greener and more eco.omical approach for treating the Mountain Pass rare earth co.centrate(MPREC),a novel "co.bination Method",including the processes of oxidizing roasting,HCI leaching and sulfuric acid roasting,is proposed in this *** this paper,the effect of phase transition behavior in hydrochloric acid leaching during oxidative roasting at 450-600℃ was *** roasting,the bastnasite in MPREC is deco.posed into CeLa_(2)O_(3)F_(3) and(Ce_(0.33),La_(0.33),Ca_(0.33))O_(1.5).As the CeLa_(2)O_(3)F_(3) phase has the fluorine-fixation effect,the generated CeLa_(2)O_(3)F_(3) phase can not be dissolved by HCI after roasting at 500 and 550℃,but it can be deco.posed by HCI after roasting at over 600℃,resulting in the improvement of the leaching rate of total F *** maximum leaching efficiency of rare earth elements(REEs) can reach 70.32 wt% at the roasting temperature of 550℃.After roasting at over 600℃,some F^-ions in the solution co.bined with RE^(3+) to form REF_(3) precipitate and enter the leaching residue,and the others are in the form of [CeF_(3)]^+ in the leaching solution during leaching,therefore,the leaching efficiency of non-ce rium REEs decreases while that of cerium element *** work provides basic research for optimizing the actual production process of MPREC.

关键词： Mountain pass rare earth mine Roasting Phase change Rare earths

更快速度下周期性短波不平顺引起的轮轨高频振动特性及控制限值

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Journal of Central South University 2024年第5期31卷 1700-1710页

作者：张航卢春房高亮杨飞孙加林 School of Civil Engineering Beijing Jiaotong UniversityBeijing 100844China research Office Planning and Standard ResearchInstitute of the National Railway AdministrationBeijing 100055China china railway Society Beijing 100044China Infrastructure Inspection research institute China Academy of Railway Sciences Co.Ltd.Beijing 100081China

随着列车运行速度的不断加快,轮轨高频振动引起的车辆、轨道部件伤损问题更加突出,尤以周期性的短波不平顺最为常见。为了掌握轮轨高频振动自下而上的传递衰减规律以及制定合理的钢轨打磨策略,有必要针对车辆系统在高频激励条件下的耦... 详细信息

随着列车运行速度的不断加快,轮轨高频振动引起的车辆、轨道部件伤损问题更加突出,尤以周期性的短波不平顺最为常见。为了掌握轮轨高频振动自下而上的传递衰减规律以及制定合理的钢轨打磨策略,有必要针对车辆系统在高频激励条件下的耦合振动特性开展深入的理论研究。本文通过对大量实测数据的拟合,得到了更宽频段范围内的轨道高低不平顺谱拟合公式,并通过反演得到了0.002~100 m波长范围内的高低不平顺样本;在此基础上建立了高速动车组-轨道刚柔耦合动力学模型,其中对轮对、钢轨均考虑了弹性体振动模态,仿真分析了周期性短波不平顺引起的轮轨高频振动特性。结果表明,车辆各部件的振动频率分布范围为30~1390 Hz,且自下至上呈逐层衰减趋势。通过提取周期性短波不平顺幅值变化对轮轨相互作用的影响规律,进一步提出了适应400 km/h高速铁路的典型波长周期性短波不平顺的量化控制限值要求。

关键词：高速铁路短波不平顺全波段高低不平顺车辆动力学响应功率谱密度

Microstructural characterization and mechanical properties of(TiC+TiB)/TA15 co.posites prepared by an in-situ synthesis method

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china Foundry 2024年第2期21卷 168-174页

作者： Zhi-yong Zhang Jiao-jiao Cheng Jia-qi Xie Shi-bing Liu Kun Shi Jun Zhao Shenyang research institute of Foundry co. Ltd.CAMShenyang 110022China National Key Laboratory of Advanced Casting Technologies Shenyang 110022China

Titanium matrix co.posites reinforced with ceramic particles are co.sidered a promising engineering material due to their co.bination of high specific strength,low density,and high *** this study,the TA15-based co.posites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting *** characterization and phase co.stitution were examined using optical microsco.y(OM),scanning electron microsco.y(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the co.posites were *** revealed that the reinforcements are distributed uniformly even in the co.posites with a high volume of TiB and ***,as the volume fraction exceeds 15%,TiB and TiC particles beco.e co.rsening and exhibit rod-like and dendritic-like *** increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature ***,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

关键词： titanium matrix co.posites microstucture microhardness tensile properties in-situ synthesis

Revealing effect of Al co.tent on oxidation of novel co.Cr-Nb-W carbide-strengthened superalloy

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Rare Metals 2024年第9期43卷 4521-4534页

作者： Chen Ling Shang-Ping Li Jie Hou He-Li Luo Central Iron&Steel research institute Beijing 100081China Beijing GAONA Materials&Technology co. Ltd.Beijing 100081China

The high-temperature oxidation behavior of novel co.Cr-Nb-W carbide-strengthened wear-resistance alloys with different Al co.tents(1wt%,2wt%and 3wt%)at 950,1000 and 1050℃was thoroughly investigated by scanning electron microsco.y,X-ray diffraction,X-ray photoelectron spectrosco.y and field emission electron probe *** porous property of NbC in-situ oxidation products(Nb_(2)O_(5),co.Nb_(2)O_(6)and co.(4)Nb_(2)O_(9))induces a multi-layered oxide scale with micropores and ***-Cr-Nb-W alloy with 1 wt%Al undergoes catastrophic oxidation and spalling above 1000℃.The outward transportation of Cr and co.is effectively restrained by a co.tinuous Al_(2)O_(3)scale formed around NbC in-situ oxidation region when Al co.tent reaches 3 wt%.The β-co.Al in co.Cr-Nb-W alloy with 3 wt%Al has an oxidation priority over eutectic carbides and the alloy matrix which are both enriched with Cr,thereby preventing the formation of Cr-depletion area and improving the self-healing ability of the oxide film.A slight change in Al co.tent has a remarkable influence on the co.perative effect of Al and Cr and multiplies the antioxidant capacity of co.Cr-Nb-W alloy above 1000℃.

关键词： High-temperature oxidation behavior Oxidation kinetics Superalloy Wear-resistant alloy Microstructure