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高速公路波形梁护栏对风吹雪灾害的影响研究

冰川冻土 2022年第6期44卷 1887-1897页

作者：魏佳北中铁建苏州设计研究院有限公司江苏苏州215004

风吹雪是新疆道路交通典型的雪害形式之一,其对道路交通的影响主要体现在降低行车能见度和导致路面大量积雪造成交通中断。新疆地区道路沿线风吹雪灾害呈现出“点多线长面广”且时空分布不均匀的特点,风吹雪涉及到风-雪-温度-湿度等多... 详细信息

风吹雪是新疆道路交通典型的雪害形式之一,其对道路交通的影响主要体现在降低行车能见度和导致路面大量积雪造成交通中断。新疆地区道路沿线风吹雪灾害呈现出“点多线长面广”且时空分布不均匀的特点,风吹雪涉及到风-雪-温度-湿度等多场耦合,是非常复杂的科学问题。同时,风吹雪灾害防治也是寒区道路交通基础设施建设和运营中亟需解决的实际问题。对于位于风吹雪多发地区的高速公路而言,由波形梁护栏引起的道路风吹雪灾害越来越突出,但目前尚缺乏对波形梁护栏这种高速公路附属设施加深风吹雪灾害的深入研究。针对上述现状,为探究其成因和防治方法,以新疆京新高速公路(G7)为工程背景,设计了波形梁护栏、缆索护栏和无护栏路堤的现场模型试验,并结合数值模拟及公路现场调研等方法,研究了高速公路波形梁护栏和缆索护栏对路面风吹雪灾害的影响,得出设置波形梁护栏和缆索护栏等的路堤路面上的风雪场分布规律。研究结果表明,风雪流从上风侧路堤坡脚处增速,到达设置在路面路肩处或中央分隔带处的波形梁处,通过波形梁护栏下部空隙运动至路面,波形梁护栏对近地面风场产生扰动,使得梁后出现弱风区,导致大量雪粒沉积。尤其当波形梁护栏下部空隙被雪填满后,波形梁后侧的路面积雪覆盖行车道,严重影响公路通行能力,而不设置护栏或者设置缆索护栏的地段有利于风雪流通过。考虑到未来气候变化的不确定性,为更好防范风吹雪对交通运营安全的影响,提出可将部分风吹雪灾害严重地段的波形梁护栏更换为符合高速公路安全要求的缆索护栏的初步建议,也可增设防雪栅、挡雪板及挡雪墙等其他防风雪措施。研究成果可为高速公路运营期间的除雪保畅工作及新疆风吹雪多发地区高速公路的建设提供有益借鉴。

关键词：风吹雪高速公路波形梁护栏模型试验数值模拟

Fabrication,microstructures,and optical properties of Yb:Lu_(2)O_(3) laser ceramics from co-precipitated nano-powders

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Journal of Advanced Ceramics 2020年第6期9卷 674-682页

作者： Ziyu LIU Guido TOCI Angela PIRRI Barbara PATRIZI Yagang FENG jiabei wei Feng WU Zhaoxiang YANG Matteo VANNINI Jiang LI Key Laboratory of Transparent Opto-functional Inorganic Materials Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Istituto Nazionale di Ottica Consiglio Nazionale delle RicercheCNR-INOSesto Fiorentino(Fi)50019Italy Istituto di Fisica Applicata“N.Carrara” Consiglio Nazionale delle RicercheCNR-IFACSesto Fiorentino(Fi)50019Italy School of Material Science and Engineering Jiangsu UniversityZhenjiang 212013China

The Yb:Lu_(2)O_(3)precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol *** 5 at% Yb:Lu_(2)O_(3)powder is in the cubic phase after calcination at 1100℃ for 4 *** powder also consists of spherical nanoparticles with the average particle and grain sizes of 96 and 49 nm,*** average grain size of the pre-sintered ceramic sample is 526 nm and that of the sample by hot isostatic pressing grows to 612 *** 1.0 mm-thick sample has an in-line transmittance of 81.6%(theoretical value of 82.2%)at 1100 *** largest absorption cross-section at 976 nm is 0.96×1^(0-20)cm^(2) with the emission cross-section at 1033 nm of 0.92×10^(-20)cm^(2) and the gain cross sections are calculated with the smallest population inversion parameter β of *** highest slope efficiency of 68.7% with the optical efficiency of 65.1% is obtained at 1033.3 nm in quasi-continuous wave(QCW)*** the case of continuous wave(CW)pumping,the highest slope efficiency is 61.0% with the optical efficiency of 54.1%.The obtained laser performance indicates that Yb:Lu_(2)O_(3)ceramics have excellent resistance to thermal load stresses,which shows great potential in high-power solid-state laser applications.

关键词： Yb:Lu_(2)O_(3)transparent ceramics co-precipitated nano-powder spectroscopic properties laser performance hot isostatic pressing

Cold Hydrostatic Sintering:From shaping to 3D printing

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Journal of Materiomics 2019年第3期5卷 496-501页

作者： Anna Jiang Daoyao Ke Ludi Xu Qiang Xu Jiang Li jiabei wei Chunfeng Hu Salvatore Grasso Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu610031China Key Laboratory of Transparent Opto-functional Inorganic Materials Shanghai Institute of CeramicsChinese Academy of SciencesShanghai201899China

We developed a novel consolidation technique,Cold Hydrostatic Sintering(CHS),which allows near full densification of *** technique is inspired by biosilicification and geological formation of siliceous *** established cold sintering method which is based on uniaxial pressure,CHS employs an isostatic pressure to enable room temperature consolidation of bulks having a complex threedimensional *** resulting material is transparent(in line transmittance exceeding 70% in the visible range)and *** drying,the Vickers hardness was as high 1.4 GPa which half of materials consolidated at 1200℃ and it is the highest among all materials processed at room *** CHS method,because of its simplicity,might be suitable for broad range of applications including 3D printing,mould forming and preparation of multi-layered *** of the absence of the firing step,CHS could be directly integrated in the manufacturing of a wide range of hybrid(organic/inorganic)materials for functional and biological applications.

关键词： Silica Cold Hydrostatic Sintering(CHS) Shaping 3D printing

A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1171-1188页

作者： wei wei Feng GUAN Xin FANG College of Intelligent Science National University of Defense Technology Naval Research Academy

A metamaterial vibration isolator, termed as wave-insulating isolator, is proposed, which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave insulation. It consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and narrow. The bandgap mechanisms, vibration isolation properties, effects of key parameters, and robustness to complex conditions are clarified. As experimentally demonstrated, the wave-insulating isolator can improve the vibration insulation in the ranges of [50 Hz, 180 Hz] and [260 Hz,400 Hz] by 15 dB and 25 dB, respectively, in contrast to the conventional isolator with the same first resonant frequency.

关键词： metamaterial and metastructure vibration isolation bandgap wave insulation plate O328 34A30 74K20

Humic acid-mediated transport of a typical soil passivation remediation product(chloropyromorphite)in saturated porous media

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Journal of Environmental Sciences 2024年第7期141卷 51-62页

作者： Xinying Li Mengjia Zhang Siyuan Li wei wei School of Environment Jiangsu Engineering Lab of Water and Soil Eco-remediationJiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response TechnologyNanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Conversion of labile Pb species into chloropyromorphite(CPY)using phosphorus-bearing amendments was considered to be an ideal strategy in soil passivation ***,the fate and transport of CPY in the soil are poorly *** study aims to fill the knowledge gap by evaluating the fate and transport of CPY under environmentally relevant conditions of humic acid(HA),pH,electrolyte concentration,and species through the saturated sandy *** showed that bare CPY colloids are basically immobile in sandy porous media while the co-existence of HA made the transport of CPY improved by30%-93.5%.Facilitated transport of CPY was attributed to the increased stability of CPY and the repulsive interaction between CPY particles and sands due to HA *** mobility of CPY was also increased with increasing pH from 5.0 to *** the pH was 9 with a10 mmol/L NaCl background solution,the stronger energy barrier between CPY and sand led to enhanced transport *** divalent Ca^(2+)had a more dramatic effect than monovalent Na^(+)on the aggregation and sedimentation of CPY colloids due to its effectivescreening of the surface charge of CPY and bridging interaction with CPY ***-LandauVerwey-Overbeek theory and attachment efficiency calculation indicated that high energy barriers were responsible for the high mobility of CPY colloids,while the retention of CPY in sands was mainly caused by secondary energy minimum and physically *** findings of this work can help to evaluate the fate of soil passivation remediation products in natural water and soil.

关键词： Chloropyromorphite DLVO theory Stability Saturated porous medium Transport

The Existence of a Meridional Curve in Closed Incompressible Surfaces in Fully Alternating Link Complements

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 73-80页

作者： wei LIN School of Mathematical Sciences Dalian University of TechnologyDalian 116024LiaoningChina

Menasco showed that a closed incompressible surface in the complement of a non-split prime alternating link in S^(3) contains a circle isotopic in the link complement to a meridian of the *** on this result,he was able to argue the hyperbolicity of non-split prime alternating links in *** et *** that if F■S×I\L is an essential torus,then F contains a circle which is isotopic in S×I\L to a meridian of *** author generalizes his result as follows:Let S be a closed orientable surface,L be a fully alternating link in S×I\If F ■ S×I\L is a closed essential surface,then F contains a circle which is isotopic in S×I\L to a meridian of L.

关键词： Fully alternating Incompressible surfaces Meridionally incompressible

Zeros of Complete Symmetric Polynomials over Finite Fields

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Journal of Systems Science & Complexity 2024年第4期37卷 1772-1788页

作者： CAO wei School of Mathematics and Statistics Minnan Normal UniversityZhangzhou 363000China

Wan and Zhang(2021) obtained a nontrivial lower bound for the number of zeros of complete symmetric polynomials over finite fields,and proposed a problem whether their bound can be *** this paper,the author improves Wan-Zhang's bound from three *** proposed results are based on the estimates related to the number of certain permutations and the value sets of non-permutation polynomials associated to the complete symmetric *** the author believes that there are still possibilities to improve the bounds and hence Wan-Zhang's bound.

关键词： Complete symmetric polynomial finite field permutation polynomial value set

High Speed Sintering:Assessing the Influence of Energy Input on Microstructure and Mechanical Properties of Polyether Block Amide(PEBA)Parts

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Chinese Journal of Polymer Science 2024年第5期42卷 675-682,I0004,I0010页

作者： Jiang-Tao Sun Zhi-Yong Fan Yi-wei Mao wei Li wei Zhu Dao-Sheng Cai Qing-Song wei State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430074China National Engineering Research Centre for High Efficiency Grinding Hunan UniversityChangsha410082China Wuhan EasyMFG Technology CO. LTDWuhan430074China

High speed sintering,a new powder-bed fusion additive manufacturing technology,utilizes infrared lights(IR)to intensely heat and melt polymer *** presence of defects such as porosity,which is associated with particle coalescence,is highly dependdent on the level of energy *** study investigate the influcence of energy input on porosity and its subsequent effects on the mechanical properties and microstructures of PEBA *** parts were manufactured with a variety of lamp powers,resulting in a range of energy input levels spanning from low to ***,they underwent testing using Archimedes’method,followed by tensile *** porosity,mechanical characteristics,and energy input exhibit a strong correlation;inadequate energy input was the primary cause of pore *** the reduced IR light power resulted in the following outcomes:porosity,ultimate tensile strength,and elongation of 1.37%,7.6 MPa,and 194.2%,*** the energy input was further increased,the porosity was reduced to as low as 0.05%and the ultimate tensile strength and elongation were increased to their peak values of 233.8%and 9.1 MPa,respectively.

关键词： High speed sintering Additive manufacturing Energy input Powder bed fusion PEBA

OnFractional(g,f,n′,m)-Critical Covered Graphs

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Journal of the Operations Research Society of China 2024年第2期12卷 446-460页

作者： wei Gao wei-Fan Wang School of Information Science and Technology Yunnan Normal UniversityKunming 650500YunnanChina Department of Mathematics Zhejiang Normal UniversityJinhua 321004ZhejiangChina

The main contribution in this article is threefold:(1)we show the necessary and sufficient condition for graphs to be fractional(g,f)-covered which can be expressed in different forms,and extended to fractional(g,f,m)-covered graphs;(2)the concept of fractional-critical covered graph is put forward and its necessary and sufficient condition is given;(3)we present the degree condition for a graph to be fractional(g,f,n′,m)-critical covered,and show that degree bound is sharp when m is ***,the related result in fractional((a,b,n′,m)-critical covered setting is also verified.

关键词： Network Fractional factor Data transmission Fractional covered graph Fractional critical covered graph