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浑水入渗对粗粒土柱孔隙及渗透性影响试验研究

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岩土工程学报 2025年第1期47卷 173-183页

作者：毛海涛张超袁古城何涛谷易山西农业大学城乡建设学院山西太原030000 重庆三峡学院土木工程学院重庆404120

浑水渗流在水利工程的反滤设计、浑水浇灌、堤坝渗流控制等方面都有较大影响,目前理论多采用稳定渗流计算方法,忽略了渗流过程中粗细颗粒与水力的耦合作用。自制渗流装置,将不同控制粒径浑水、不均匀系数粗粒土柱和水头等作为基本控制因... 详细信息

浑水渗流在水利工程的反滤设计、浑水浇灌、堤坝渗流控制等方面都有较大影响,目前理论多采用稳定渗流计算方法,忽略了渗流过程中粗细颗粒与水力的耦合作用。自制渗流装置,将不同控制粒径浑水、不均匀系数粗粒土柱和水头等作为基本控制因素,研究不同工况下浑水中悬浮颗粒对粗粒土土柱中的渗透特性影响;推导了变渗透系数浑水渗流计算微分方程,通过对比验证和公式修正,结果表明:粗粒土中颗粒淤积率与控制粒径C_(0.075)含量符合Boltzmann函数关系;C_(0.075)是重要的影响因子,浑水颗粒在粗粒土柱的运移、沉积和淤堵形态过程大致可分为4种形态:表层堆积淤堵形态(S型);表层-内部双重淤堵形态(S-I型);内部孔隙淤堵形态(I型);暂态孔隙淤堵形态(P型)。土柱C_(u)越大,孔隙度越小,浑水颗粒在粗粒土中运移也越困难,土柱填充性就越差;水头加剧了颗粒在土柱内部运移的速度,但也加速了其在顶部的沉积并封堵;S型时土柱0~2cm渗透系数下降速率最大,封堵时总体渗透系数最小,2cm以下相对孔隙率及随深度逐渐减小;S-I和I型土柱下部渗透系数明显滞后于上部,相对孔隙率存在临界深度(约为4~6cm);P型时土柱整体相对孔隙率基本无变化。

关键词：颗粒渗流粗粒土浑水堵塞

Wing/body kinematics measurement and force and moment analyses of the takeoff flight of fruitflies

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Acta Mechanica Sinica 2014年第4期30卷 495-506页

作者： mao-Wei Chen mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics Beihang University

In the paper, we present a detailed analysis of the takeoff mechanics of fruitflies which perform voluntary takeoff flights. Wing and body kinematics of the insects during takeoff were measured using Based on the measured data, high-speed video techniques. inertia force acting on the insect was computed and aerodynamic force and moment of the wings were calculated by the method of computational fluid dynamics. Subtracting the aerodynamic force and the weight from the inertia force gave the leg force. The following has been shown. In its voluntary takeoff, a fruitfly jumps during the first wingbeat and becomes airborne at the end of the first wingbeat. When it is in the air, the fly has a relatively large ＂initial＂ pitch-up rotational velocity （more than 5 000~/s） resulting from the jumping, but in about 5 wingbeats, the pitch-up rotation is stopped and the fly goes into a quasi-hovering flight. The fly mainly uses the force of jumping legs to lift itself into the air （the force from the flapping wings during the jumping is only about 5%-10% of the leg force）. The main role played by the flapping wings in the takeoff is to produce a pitch-down moment to nullify the large ＂initial＂ pitch-up rotational velocity （otherwise, the fly would have kept pitching-up and quickly fallen down）.

关键词： Fruitfly· Takeoff flight ·Body and wing kine-matics Aerodynamic and leg forces

人口流动对我国高等教育资源配置的影响及对策研究

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黑龙江高教研究 2025年第1期43卷 31-37页

作者：陈茂建吴刚龙福建教育学院福建福州350001 黎明职业大学福建泉州362000

基于2013一2022年31个省份面板数据,使用固定效应模型实证检验人口流动对我国高等教育资源配置的影响。结果发现:第一,人口流动对高等教育资源配置具有显著影响作用,人口净流入地区和净流出地区分别对高等教育资源配置产生负向影响和正... 详细信息

基于2013一2022年31个省份面板数据,使用固定效应模型实证检验人口流动对我国高等教育资源配置的影响。结果发现:第一,人口流动对高等教育资源配置具有显著影响作用,人口净流入地区和净流出地区分别对高等教育资源配置产生负向影响和正向影响;第二,人口流动对高等教育资源配置的影响因地区经济发展水平、城镇化水平以及人口结构的不同而存在差异,东部地区、城镇化水平为中等的地区、中等文化水平程度在人口流动对高等教育资源配置的影响方面均最显著。基于研究结果一,提出以下对策:一是加强人口流入地区的高等教育资源配置;二是优化人口流出地区的高等教育资源配置。基于研究结果二,提出以下对策:一是加强东部地区的高等教育资源配置;二是注重城镇化水平中等地区的高等教育资源配置;三是加强教育普及程度相对均衡地区的高等教育资源配置。

关键词：人口流动高等教育资源配置对策

激光诱导荧光技术与地下水重金属原位检测应用进展

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岩矿测试 2025年第1期44卷 19-34页

作者：毛康薛家奇陈卓张华中国科学院地球化学研究所环境地球化学国家重点实验室贵州贵阳550081

对地下水重金属污染进行现场检测,是快速识别重金属种类和评价污染程度的重要手段。激光诱导荧光技术(LIF)利用特定荧光探针,在目标重金属存在下,通过激光诱导荧光探针产生/猝灭荧光,从而完成对重金属的识别和检测,具有快速甄别地下水... 详细信息

对地下水重金属污染进行现场检测,是快速识别重金属种类和评价污染程度的重要手段。激光诱导荧光技术(LIF)利用特定荧光探针,在目标重金属存在下,通过激光诱导荧光探针产生/猝灭荧光,从而完成对重金属的识别和检测,具有快速甄别地下水重金属污染特性和无损获取其价态的优势。本文在简述LIF检测重金属原理和LIF原位检测地下水重金属装备基础上,重点从荧光探针合成及其在重金属传感检测方法的构建上总结了基于不同荧光探针的LIF现场检测重金属的研究进展。目前可用于重金属检测的荧光探针包括以小分子探针、有机大分子和聚集诱导发光为主的有机荧光探针和以金纳米簇、量子点和金属有机框架材料为代表的纳米荧光探针。这些探针的合成及其对应的传感检测方法的构建表明LIF技术在地下水重金属检测中具有巨大优势。而针对地下水重金属检测的LIF设备研发方面的成果虽不如荧光传感检测方法丰富,但已研制出部分重金属的传感器和检测装备,表现出良好的应用前景。未来研究将会聚焦在地下水重金属主控因子识别和抗干扰技术研发、荧光探针合成与LIF检测方法构建、重金属传感部件和检测装备集成研制,以及检测技术标准化,为后续场地地下水典型重金属LIF检测技术的研究提供参考。

关键词：地下水重金属激光诱导荧光荧光探针现场检测

Experimental study of dual nano-network, high-temperature resistant aerogel material as an integration of thermal management functions

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Journal of Energy Chemistry 2025年第1期 157-170页

作者： Yueyue Xiao Tianke mao Zun Zhao Yuelei Pan Heping Zhang Xudong Cheng State Key Laboratory of Fire Science University of Science and Technology of China

Thermal management system is highly desirable to guarantee the performance and thermal safety of lithium-ion batteries,but it reduces the energy density of battery modules and even is unable to provide highly effective ***,a thermal management function integrated material is presented based on high-temperature resistant aerogel and phase change material and is applied at both charge–discharge process and thermal runaway *** this sandwich structure Paraffin@SiC nanowire/Aerogel sheet （denoted as PA@SAS） system,SiC nanowires endow the middle aerogel sheet （SAS） a dual nano-network *** enhanced mechanical properties of SAS were studied by compressive tests and dynamic mechanical ***,the thermal conductivity of SAS at 600°C is only 0.042 W/（m K）.The surface phase change material layers facilitate temperature uniformity of batteries （surface temperature difference less than 1.82°C） through latent ***,a large-format battery module with four 58 Ah LiNi0.5Co0.2Mn0.3O2LIBs was ***@SAS successfully prevents thermal runaway propagation,yielding a temperature gap of 602°C through the 2 mm-thick cross ***@SAS also exhibits excellent performance in other safety issues such as temperature rise rate,flame heat flux,*** lightweight property and effective insulation performance achieves significant safety enhancement with mass and volume energy density reduction of only 0.79%and 5.4%,*** originality of the present research stems from the micro and macro structure design of the proposed thermal management material and the combination of intrinsic advantages of every *** work provides a reliable design of achieving the integration of thermal management functions into an aerogel composite and improves the thermal safety of lithium-ion batteries.

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On intergranular mechanical interactions and the theory of deformation crystallography of metals

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Frontiers of Materials Science 2021年第2期15卷 192-201页

作者： Weimin mao School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyArding Street 7Baotou 014010China Department of Materials University of Science and Technology BeijingXue-Yuan Road 30Beijing 100083China

The equilibrium of intergranular stress and strain can be realized simultaneously,whereas five independent slip systems of the Taylor principle and the criterion of minimal internal work are *** fact,the Taylor principle applied in current theories is incorrect both in practice and theory,in which the activation mechanism of plastic deformation systems must violate the Schmid’s law and deviate from the elastic-plastic characteristics of deformed *** intergranular reaction stress(RS)during deformation can be calculated according to Hooke’s law and elastic limit without additional subjective presupposition,therefore the RS theory is established *** the combination of the RS(the intergranular elastic effect)and the external loading the slips penetrating grains are activated and produce deformation texture,but certain non-penetrating slips near grain boundaries will become active(the intergranular plastic effect)and produce some random texture when a RS reaches the yield strength of *** RS theory is simple,intuitive and reasonable,based on which the texture simulation can well reproduce the texture formation of various metals under different external loadings and under different crystallographic mechanisms.

关键词： deformation crystallography plastic strain stress equilibrium Taylor principle reaction stress texture simulation

A generalization of silting modules and Tor-tilting modules

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Frontiers of Mathematics in China 2022年第4期17卷 715-730页

作者： Lixin mao Department of Mathematics and Physics Nanjing Institute of TechnologyNanjing211167China

We introduce the concept of weak silting modules,which is a generalization of both silting modules and Tor-tilting *** is shown that W is a weak silting module if and only if its character module W+is *** properties o... 详细信息

关键词： Silting module cosilting module weak silting module Tor-tilting module

ANISOTROPY OF WORK HARDENING IN 5456 ALUMINUM ALLOY

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中国有色金属学会会刊：英文版 1998年第1期8卷 40-44页

作者： mao, Weimin Univ of Science and Technology Beijing Beijing China

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ＡＮＩＳＯＴＲＯＰＹＯＦＷＯＲＫＨＡＲＤＥＮＩＮＧＩＮ５４５６ＡＬＵＭＩＮＵＭＡＬＬＯＹ①ＭａｏＷｅｉｍｉｎＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｒｉｎｇ，ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌ...

关键词： aluminum alloy rolling deformation texture work hardening anisotropy

Wing Kinematics, Aerodynamic Forces and Vortex-wake Structures in Fruit-flies in Forward Flight

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Journal of Bionic Engineering 2016年第3期13卷 478-490页

作者： XueguangMeng mao Sun Institute of Fluid Mechanics Beijing University of Aeronautics and Astronautics Beijing 100191 China

Wing kinematics in forward-flying fruit-flies was measured using high-speed cameras and flows of the flapping wing were calculated numerically. The large lift and thrust coefficients produced by the wing were explained. The wing flaps along a forward-tilting stroke plane. In the starting portion of a half-stroke （an upstroke or downstroke）, the wing pitches down to a small pitch angle; during the mid portion （the wing has built up its speed）, it first fast pitches up to a large pitch angle and then maintains the pitch angle; in the ending portion, the wing pitches up further. A large aerodynamic force （normal to the wing surface） is produced during the mid portion of a half-stroke. The large force is produced by the fast-pitching-up rotation and delayed-stall mechanisms. As a result of the orientation of wing, the thrust that propels the insect is produced by the upstroke and the major part of the vertical force that supports the weight is produced by the downstroke. In producing the thrust the upstroke leaves a ＂vortex ring＂ that is almost vertical, and in producing the vertical force the downstroke leaves a ＂vortex ring＂ that is almost horizontal.

关键词： fruit-fly wing kinematics forward flight Navier-Stokes simulation vortex