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Three-dimensional numerical simulation and earth pressure analysis on double-row piles with consideration of spatial effects

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第10期12卷 758-770页

作者： zi-han WANG Jian ZHOU Department of Geotechnical Engineering Tongji University Shanghai 200092 China

As a new kind of technology in retaining structures, the characteristics of double-row piles are significantly affected by spatial effects. In this paper, double-row piles as a retaining structure are simulated numerically in three-dimension by finite element software PLAXIS 3D FOUNDATION. The behavior differences of piles in different positions around the foundation pit are analyzed. By changing the parameters, including the length-width ratio, the excavation depth, the distance between rows and the diameter of piles, the variations of the lateral deformation, the bending moment and the earth pressure around the piles are determined. The reasonable values of parameters and some suggestions with consideration of earth pressure are proposed for the design of double-row piles as a retaining structure. The results show that the lateral deformation and bending moment are the largest in the middle of long side of the foundation pit, which is identified as the most unfavorable position. It is indicated that the earth pressure between rows above pit bottom is close to active earth pressure, while the earth pressure between rows under pit bottom is close to static earth pressure. It is suggested that 1/2-2/3 of pile length, 0.6-1.2 m, 3d-6d, and 2d-2.5d be chosen as embedded depth of piles, diameter of piles, distance between rows, and distance between piles, respectively, where d is the pile diameter.

关键词： Double-row piles Retaining structure Spatial effect Finite element Earth pressure

Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第01期 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo han Guo zi-Fei Xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

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基于纳秒LIBS的氢气/空气火焰混合分数测量研究

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光谱学与光谱分析 2025年第1期45卷 24-29页

作者：刘子晗刘艳韩磊单沅鲁政高强李帅瑶李博天津大学内燃机燃烧学国家重点实验室天津300072 中国科学院工程热物理研究所北京100190

在双碳政策和化石能源短缺的背景下,氢能作为高效环保的清洁能源,受到广大研究人员的关注。氢气/空气混合燃烧作为推动氢能规模化应用的重要途径,其燃烧机理和关键参数的测量技术成为目前研究的热点。燃空当量比是表征燃烧过程中燃料与... 详细信息

在双碳政策和化石能源短缺的背景下,氢能作为高效环保的清洁能源,受到广大研究人员的关注。氢气/空气混合燃烧作为推动氢能规模化应用的重要途径,其燃烧机理和关键参数的测量技术成为目前研究的热点。燃空当量比是表征燃烧过程中燃料与氧化剂混合程度的重要参数,直接影响燃烧的开始、自持以及燃烧化学反应的活跃程度。因此,对燃烧过程中的局部当量比实时在线监测,对于改善燃烧效率、控制燃烧过程具有重要意义。目前,可以实时测量氢气/空气火焰当量比的方法相对较少,激光光谱技术作为一种非侵入式的测量方法,不仅具有实时在线测量的能力,还具有快速、原位、远程分析、多元素同时在线监测等特点,在燃烧测量领域具有重要的应用潜力。采用纳秒激光诱导击穿光谱技术对氢气和空气燃烧场的燃空当量比进行测量研究。氢气和空气在管内混合后,由射流口喷出形成射流燃烧火焰场。激光通过透镜聚焦到射流燃烧场中击穿并产生等离子体,其等离子体的发射光谱由光谱仪采集,实验发现光谱中H 656 nm和O 777 nm具有很强的发射强度,且光谱强度随着当量比的变化,呈现规律性变化趋势。因此,采用H 656 nm和O 777 nm的光谱分别标示氢气和空气,并将其比值作为燃空当量比的测量参量。实验在氢气空气混合均匀的低速流场中测量了不同当量比下H 656 nm与O 777 nm的光谱强度比值,并与当量比建立标定曲线,实验发现该标定曲线对燃烧场和非燃烧场同样适用。基于标定曲线,我们研究了存在外界掺混情况下,射流燃烧场的局部燃空当量比情况。在当量比1.0,流场速度为20 m·s^(-1)的射流燃烧场中,测量了射流中心位置不同高度的燃空当量比变化情况,并在相同工况下进行了数值模拟。模拟结果与实验测量吻合较好,验证了纳秒激光诱导击穿光谱技术测量氢气/空气混合气的燃空当量比的可行性。该方法可为氢气燃烧基础研究及数值模拟提供技术支持。

关键词：激光诱导击穿光谱氢能当量比模拟

“秦人好兴事”及秦大型工程的历史言说与行政史教训

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河北学刊 2025年第1期45卷 1-10页

作者：王子今湘潭大学哲学与历史文化学院(碧泉书院) “古文字与中华文明传承发展工程”协同攻关创新平台中国人民大学国学院

由余评价秦人工程“使人为之,亦苦民矣”,战国时人言“秦人好兴事”。秦统一之后兴建的著名工程,则有长城、阿房宫、骊山以及驰道、直道等。后世史论、政论或认为,秦工程规模之大,致使人力资源的扼杀式消耗、社会民生的摧毁性损伤、经... 详细信息

由余评价秦人工程“使人为之,亦苦民矣”,战国时人言“秦人好兴事”。秦统一之后兴建的著名工程,则有长城、阿房宫、骊山以及驰道、直道等。后世史论、政论或认为,秦工程规模之大,致使人力资源的扼杀式消耗、社会民生的摧毁性损伤、经济秩序的全面化破坏,是引发秦短促而亡的重要原因之一。有迹象表明,秦大型工程是以军事化形式组织和管理,显示出极高的效率。其所付出的社会代价,尤其是民众的生命成本,则体现出惊人的残酷。汉初营建非常重要的营造项目亦多注意工程规划的合理与人力动员的收敛,对秦政相关内容取“拨乱反正”的态度,体现出历史走向进步的趋势。

关键词：秦朝 “秦人好兴事” 工程效率生命成本

Thermodynamic and experimental study of high-temperature roasting of blast furnace gas ash for recovery of metallic zinc and iron

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Journal of Iron and Steel Research International 2024年第1期31卷 108-120页

作者： zi-han Wang Jing Guo han-jie Guo Bin Li School of Metallurgical Engineering University of Science and Technology BeijingBeijing100083China School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina

A high-temperature reduction roasting method was used to achieve metallic iron and zinc recovery from blast furnace gas ash(BFA).The reduction processes for Zn-containing and Fe-containing oxides were analyzed in detail by using ther-modynamic equilibrium calculation and the principle of minimum free *** results showed that the main reaction in the system is the reduction of ZnFe_(2)_(4)and iron *** the full temperature range,iron oxides were more easily reduced than zinc *** of the amount of CO contained in the system,the reduction of ZnO to Zn was difficult to proceed below the boiling point(906℃)of *** the reduction temperature is below 906℃,the reduction process of zinc ferrate was ZnFe_(2)_(4)→ZnO;when the reduction temperature is above 906℃,its reduction process becomed ZnFe_(2)_(4)→ZnO→Zn(g).The metallization and dezincification rates of the BFA gradually increased with increasing reaction *** the C/O ratio increased,the metallization and dezincification rates first increased and then *** effect of reduction time on BFA reduction was similar to that of reaction temperature.

关键词： Blast furnace gas ash Thermodynamics zinc removal Iron reduction High-temperature reduction roasting Integrated utilization

Wear behavior of Zn-38Al-3.5Cu-1.2Mg/SiC_(p) composite under different stabilization treatments

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International Journal of Minerals,Metallurgy and Materials 2022年第6期29卷 1270-1279页

作者： Sheng Liu Qing Yuan Yutong sima Chenxi Liu Fang han Wenwei Qiao The State Key Laboratory of Refractories and Metallurgy Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of EducationWuhan University of Science and TechnologyWuhan 430081China Wuhan Heavy Industry Casting&Forging Co.Ltd. China State Shipbuilding Corporation LimitedWuhan 430080China Jiangsu Huaneng Cable Company Limited Gaoyou 225613China

A Zn-38Al-3.5Cu-1.2Mg composite reinforced with nano-SiC_(p) was fabricated via stirring-assisted ultrasonic *** improve the abrasive resistance of the Zn-38Al-3.5Cu-1.2Mg/SiC_(p) composite,several stabilization treatments with distinct solid solutions and aging temperatures were *** results indicated that the optimal stabilization treatment for the Zn-38Al-3.5Cu-1.2Mg/SiC_(p) composite comprised solution treatment at 380℃for 6 h and aging at 170℃for 48 *** stabilization treatment led to the formation of dispersive and homogeneous nano-SiC_(p).During the friction wear condition,the nano-SiC_(p) limited the microstructure evolution from the hardα(Al,Zn)phase to the softβ(Al,Zn)***,the increased amount of nano-SiC_(p) improved the grain dimension and contributed to the composite abrasive ***,the stabilization treatment suppressed the crack initiation and propagation in the friction wear process,thereby improving the abrasive resistance of the Zn-38Al-3.5Cu-1.2Mg/SiC_(p) composite.

关键词： composite ultrasonic vibration stabilization abrasive resistance microstructure evolution

A cellulose-based lithium-ion battery separator with regulated ionic transport and high thermal stability for extreme environments

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Nano Research 2025年第1期18卷 315-322页

作者： Kun-Peng Yang Song Xie zi-Meng han Hao-Cheng Liu Chong-han Yin Wen-Bin Sun Zhang-Chi Ling Huai-Bin Yang De-han Li Qing-Fang Guan Shu-Hong Yu Department of Chemistry New Cornerstone Science LaboratoryInstitute of Biomimetic Materials&ChemistryAnhui Engineering Laboratory of Biomimetic MaterialsDivision of Nanomaterials&ChemistryHefei National Research Center for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefei 230026China Institute of Innovative Materials Department of Materials Science and EngineeringDepartment of ChemistrySouthern University of Science and TechnologyShenzhen 518055China

Separators play a critical role in lithium-ion ***,the restrictions of thermal stability and inferior electrical performance in commercial polyolefin separators significantly limit their applications under harsh ***,we report a cellulose-assisted self-assembly strategy to construct a cellulose-based separator massively and *** an ultrahigh ionic conductivity in electrolytes of 3.7 mS·cm^(-1) and the ability to regulate ion transport,the obtained separator is a promising alternative for high-performance lithium-ion *** addition,integrated with high thermal stability,the cellulose-based separator endows batteries with high safety at high temperatures,greatly expanding the application scenarios of energy storage devices in extreme environments.

关键词： lithium-ion batteries bio-inspired materials battery separators cellulose nanofiber ultrahigh ionic conductivity high safety

Enhanced switching electric field and breakdown strength of epoxy composites with core-shell silicon carbide nanoparticles

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High Voltage 2023年第3期8卷 583-589页

作者： Yongsen han zi Wang Jian Sun Zhonghua Li Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinHeilongjiangChina

Silicon carbide(SiC)is widely used to improve the non-linear conductivity of non-linear resistive field grading *** this paper,the SiC nanoparticles are modified into core-shell nanoparticles with silica(SiO_(2))coating on the surface and are characterised by transmission electron microscopy and X-ray diffraction,*** 7 wt%SiC@SiO_(2)/epoxy nanocomposite is then prepared,and the pure epoxy and 7 wt%SiC/epoxy nanocomposite are prepared as a *** relative permittivity,thermally stimulated current,conductivity and breakdown strength are studied,*** presence of SiO_(2)shell around SiC nanoparticles has a great effect on the relative permittivity and trap *** epoxy nanocomposites show non-linear conductivity characteristics,compared with pure *** 7 wt%SiC@SiO_(2)/epoxy nanocomposite has higher switching electric field and breakdown strength than the 7 wt%SiC/epoxy nanocomposite,which is helpful for the application of non-linear resistive field grading composite in higher-voltage equipment or components.

关键词： nanoparticles composites composite

ON POTENT ELEMENTS AND PSEUDO CLEAN RINGS

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数学杂志 2025年第1期45卷 39-47页

作者： DING Yan GAO han-peng LIU Xin-yi YAN zi-yi ZhanG Ting School of Mathematical Sciences Anhui UniversityHefei 230601China

In this paper,potent index of an element and pseudo clean rings are *** properties and examples of pseudo clean rings are *** also show that Zm is pseudo clean for every 2≤m∈Z and pseudo clean rings are ***,we prove... 详细信息

关键词： clean rings strongly J-clean rings pseudo clean rings potent elements