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Microwave response characteristics and influencing factors of ores based on dielectric properties of synthetic samples

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第2期14卷 315-328页

作者： Feng Lin Xia-Ting Feng Chengxiang Yang Shiping Li jiuyu Zhang Xiangxin Su Tianyang Tong Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China

In order to understand the influence of different factors on the microwave response characteristics of ores,the effects of electrical conductivity,metal mineral content,compactness,metal mineral distribution,microwave frequency and temperature on the dielectric properties of synthetic ores(metal mineral and quartz)were *** heating tests were carried out on three types of natural ores(Hongtoushan copper ore,Sishanling iron ore and Dandong gold ore)with significant differences in metal mineral *** test results showed that under microwave irradiation,the stronger the electrical conductivity of the metal minerals,the smaller the penetration depth in synthetic *** those metal minerals with lower electrical conductivity,the microwave absorption coefficient of the synthetic samples increases with increasing metal mineral *** those metal minerals with higher electrical conductivity,the microwave absorption coefficient of the samples first increases and then decreases as the metal mineral content *** the metal minerals are distributed in layers,the penetration depth is much less than that given a uniform *** penetration depth in the sample at microwave frequency of 915 MHz is greater than that at 2.45 *** higher the electrical conductivity of metal minerals used in synthetic ores,the higher the high-temperature sensitivity of electromagnetic shielding coefficient(0.C-500.C).The Hongtoushan copper ore with high metal mineral content exhibits obvious size *** effects of ore structure and crystal particle size on the distribution characteristics of microcracks were *** on the test results,a quantitative prediction model of microwave sensitivity of ore was proposed,which provides guidance for the prediction of ore heating effect and the selection of microwave heating sequence of ore.

关键词： Metal minerals Electrical conductivity Metal mineral content Synthetic ore Prediction model

Probing the intriguing frictional behavior of hydrogels during alternative sliding velocity cycles

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Friction 2023年第12期11卷 2329-2341页

作者： Yiming ZHAO Gang YI jiuyu CUI Ziqian ZHAO Yonggan YAN Luxing WEI Jinlong SHAO Hongbo ZENG Jun HUANG Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education National Demonstration Center for Experimental Mechanical Engineering EducationSchool of Mechanical EngineeringShandong UniversityJinan 250061China Shandong Key Laboratory of Advanced Organosilicon Materials and Technologies Zibo 256401China Department of Chemical and Materials Engineering University of AlbertaEdmontonAlberta T6G 1H9Canada Department of Periodontology School and Hospital of StomatologyCheeloo College of MedicineShandong University&Shandong Key Laboratory of Oral Tissue RegenerationJinan 250061China Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration Jinan 250012China

Understanding the friction behavior of hydrogels is critical for the long-term stability of hydrogelrelated bioengineering *** of maintaining a constant sliding velocity,the actual motion of bio-components(e.g.,articular cartilage and cornea)often changes ***,it is important to study the frictional properties of hydrogels serving under various sliding *** this work,an unexpected low friction regime(friction coefficientμ<10^(-4) at 1.05×10^(-3) rad/s)was observed when the polyacrylamide hydrogel was rotated against a glass substrate under alternative sliding velocity ***,compared with the friction coefficients under constant sliding velocities,the measuredμdecreased significantly when the sliding velocity changed abruptly from high speeds(e.g.,105 rad/s)to low speeds(e.g.,1.05×10^(-3) rad/s).In addition,μexhibited a downswing trend at low speeds after experiencing more alternative sliding velocity cycles:the measuredμat 1.05 rad/s decreased from 2×10^(-2) to 3×10^(-3) after 10 friction *** is found that the combined effect of hydration film and polymer network deformation determines the lubrication and drag reduction of hydrogels when the sliding velocity changes *** observed extremely low friction during alternative sliding velocity cycles can be applied to reduce friction at contacted *** work provides new insights into the fundamental understanding of the lubrication behaviors and mechanisms of hydrogels,with useful implications for the hydration lubrication related engineering applications such as artificial cartilage.

关键词： hydrogel friction alternative sliding velocity ultra-low friction coefficient drag reduction

A novel true triaxial test system for microwave-induced fracturing of hard rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第5期13卷 961-971页

作者： Xia-Ting Feng jiuyu Zhang Chengxiang Yang Jun Tian Feng Lin Shiping Li Xiangxin Su Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China

This study introduces a test system for microwave-induced fracturing of hard rocks under true triaxial *** test system comprises a true triaxial stress loading system,an open-ended microwaveinduced fracturing system,a data acquisition system,an acoustic emission(AE)monitoring system,and an auxiliary specimen loading ***-induced surface and borehole fracturing tests under true triaxial stress were fulfilled for the first time,which overcomes the problem of microwave leakage in the coupling loading of true triaxial stress and *** developing the dynamic monitoring system,the thermal response and fracture evolution were obtained during microwave *** monitoring system includes the infrared thermometry technique for monitoring rock surface temperature,the distributed optic fiber sensing technique for monitoring temperature in borehole in rock,the AE technique and two-dimensional digital speckle correlation technique for monitoring the evolution of thermal damage and the rock fracturing *** validate the advantages of the test system and investigate the characteristics of microwave-induced fracturing of hard rocks,the study demonstrates the experimental methods and results for microwave-induced surface and borehole fracturing under true triaxial *** results show that thermal cracking presented intermittent characteristics(calm eactiveecalm)during microwave-induced surface and borehole fracturing of *** addition,true triaxial stress can inhibit the development and distribution of thermal cracks during microwave-induced surface *** microwave-induced borehole fracturing occurs,it promotes the distribution of thermal cracks in rock,but inhibits the width of *** results also prove the reliability of the test system.

关键词： Deep hard rock engineering True triaxial apparatus Microwave-induced fracturing of hard rocks Electromagnetic compatibility Dynamic monitoring Evolution of rock fracturing

Characterization of extracellular phosphatase activities in periphytic biofilm from paddy field

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Pedosphere 2021年第1期31卷 116-124页

作者： Shujie CAI Kaiying DENG Jun TANG Rui SUN Hailong LU jiuyu LI Yonghong WU Renkou XU Institute of Soil Science Chinese Academy of SciencesNanjing 210008China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Periphytic biofilms exist widely in paddy fields, but their influences on the hydrolysis of organic phosphorus(P) have rarely been investigated. In this study,a periphytic biofilm was incubated in a paddy soil solution, and hydrolysis kinetic parameters(half-saturation constant(Km) and maximum catalytic reaction rate(Vmax)), optimal environmental conditions, substrate specificity, and response to different P regimes of the phosphatase activities in the periphytic biofilm were determined, in order to characterize extracellular phosphatase activities in periphytic biofilms from paddy fields. The results indicated that the periphytic biofilm could produce an acid phosphomonoesterase(PMEase), an alkaline PMEases, and a phosphodiesterase(PDEase). These three phosphatases displayed high substrate affinity, with Km values ranging from 141.03 to 212.96 μmol L^(-1). The Vmax/Km ratios for the phosphatases followed the order of alkaline PMEase > acid PMEase > PDEase, which suggested that the PMEases, especially the alkaline PMEase, had higher catalytic efficiency. The optimal pH was 6.0 for the acid PMEase activity and 8.0 for the PDEase activity, and the alkaline PMEase activity increased with a pH increase from 7.0 to 12.0. The optimal temperature was 50℃ for the PMEases and 60℃ for the PDEase. The phosphatases showed high catalytic efficiency for condensed P over a wide pH range and for orthophosphate monoesters at pH 11.0, except for inositol hexakisphosphate at pH 6.0. The inorganic P supply was the main factor in the regulation of phosphatase activities. These findings demonstrated that the periphytic biofilm tested had high hydrolysis capacity for organic and condensed P,especially under P-limited conditions.

关键词： hydrolysis capacity kinetic parameters optimal environmental conditions phosphodiesterase phosphomonoesterase phosphorus hydrolysis phosphorus supply substrate specificity

An ultra-fast charging strategy for lithium-ion battery at low temperature without lithium plating

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Journal of Energy Chemistry 2022年第9期31卷 442-452,I0013页

作者： Yudi Qin Pengyu Zuo Xiaoru Chen Wenjing Yuan Rong Huang Xiaokan Yang jiuyu Du Languang Lu Xuebing Han Minggao Ouyang State Key Laboratory of Automotive Safety and Energy School of Vehicle and MobilityTsinghua UniversityBeijing 100084China Beijing LianYu Technology Co. Ltd.Beijing 100084China Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Beijing Electric Vehicle Co. Ltd.Beijing 100176China

Conventional charging methods for lithium-ion battery(LIB)are challenged with vital problems at low temperatures:risk of lithium(Li)plating and low charging *** study proposes a fast-charging strategy without Li plating to achieve high-rate charging at low temperatures with bidirectional *** strategy combines the pulsed-heating method and the optimal charging method via precise control of the battery states.A thermo-electric coupled model is developed based on the pseudo-twodimensional(P2D)electrochemical model to derive charging *** current maps of pulsed heating and charging are generated to realize real-time ***,our proposed strategy achieves a 3 C equivalent rate at 0℃ and 1.5 C at-10℃ without Li plating,which is 10–30 times faster than the traditional *** entropy method is employed to balance the charging speed and the energy efficiency,and the charging performance is further *** practical application,the power limitation of the charger is considered,and a 2.4 C equivalent rate is achieved at 0℃ with a 250 kW maximum power *** novel strategy significantly expands LIB usage boundary,and increases charging speed and battery safety.

关键词： Lithium-ion battery Pulsed heating Fast charging Low temperature Lithium deposition

Field test of high-power microwave-assisted mechanical excavation for deep hard iron ore

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 1922-1935页

作者： Feng Lin Xia-Ting Feng Shiping Li Xiao Hai jiuyu Zhang Xiangxin Su Tianyang Tong Jianchun Song Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China Benxi Longxin Mining Corporation Limited Benxi117000China

Microwave-assisted mechanical excavation has great application prospects in mines and tunnels,but there are few field experiments on microwave-assisted rock *** paper takes the Sishanling iron mine as the research object and adopts the self-developed high-power microwave-induced fracturing test system for hard rock to conduct field experiments of microwave-induced fracturing of iron *** heating and reflection evolution characteristics of ore under different microwave parameters(antenna type,power,and working distance)were studied,and the optimal microwave parameters were ***,the ore was irradiated with the optimal microwave parameters,and the cracking effect of the ore under the action of the high-power open microwave was *** results show that the reflection coefficient(standing wave ratio)can be rapidly(<5 s)and automatically adjusted below the preset threshold value(1.6)as microwave irradiation is *** using a right-angle horn antenna with a working distance of 5 cm,the effect of automatic reflection adjustment reaches the best among other antenna types and working *** the working distance is the same,the average temperature of the irradiation surface and the area of the high-temperature area under the action of the two antennas(right-angled and equal-angled horn antenna)are basically the same and decrease with the increase of working *** optimal microwave parameters are:a right-angle horn antenna with a working distance of 5 ***,in further experiments,the optimal parameters were used to irradiate for 20 s and 40 s at a microwave power of 60 kW,*** surface damage extended 38 cm×30 cm and 53 cm×30 cm,respectively,and the damage extended to a depth of about 50 *** drilling speed was increased by 56.2%and 66.5%,respectively,compared to the case when microwaves were not used.

关键词： Microwave parameters High power Field experiment Mechanical mining

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微裂缝油-气-水多相流动力学机制与规律

中南大学学报（自然科学版） 2021年第11期52卷 3990-3998页

作者：王付勇赵久玉油气资源与探测国家重点实验室北京102249 中国石油大学(北京)非常规油气科学技术研究院北京102249 中国石油大学(北京)地球科学学院北京102249

注气重力驱是碳酸盐岩油藏一种有效的开发方式,但碳酸盐岩油藏裂缝广泛发育,注气过程中油-气-水多相流动规律复杂,力学机制不清,分析裂缝中油-气-水多相流动力学机制尤为重要。首先,考虑注气压差、重力、黏滞阻力和毛管力等各种作用力,... 详细信息

注气重力驱是碳酸盐岩油藏一种有效的开发方式,但碳酸盐岩油藏裂缝广泛发育,注气过程中油-气-水多相流动规律复杂,力学机制不清,分析裂缝中油-气-水多相流动力学机制尤为重要。首先,考虑注气压差、重力、黏滞阻力和毛管力等各种作用力,构建裂缝油-气-水多相流动力学模型,得到裂缝中流体所受剪切应力与平均流速的关系;其次,推导油-气-水界面运移时间的解析表达式;最后,定量研究裂缝宽度、注气压差、润湿性、毛管力等因素对多相流动的影响,分析裂缝中各作用力的相互制约关系,提出一种可忽略毛管力时的临界裂缝宽度定量判别方法。研究结果表明:裂缝多相流动速度与裂缝宽度呈二次方关系,裂缝越宽,流动速度越大;随着裂缝宽度增大,润湿性对流动速度的影响逐渐变小;当油-气毛管力和油-水毛管力合力与流动方向一致时,毛管力合力越大,流动速度越快;当毛管力合力小于10^(-10)N,毛管力对流动速度的影响可以忽略不计。所构建的裂缝宽度-受力双对数图版可以有效判定可忽略毛管力时的临界裂缝宽度。

关键词：碳酸盐岩油藏裂缝注气多相流动力学机制渗流规律

基于深度学习的数字岩心图像重构及其重构效果评价

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中南大学学报（自然科学版） 2022年第11期53卷 4412-4424页

以鄂尔多斯盆地延长组致密砂岩为研究对象,基于超分辨率生成对抗神经网络(SRGAN)提高数字岩心图像分辨率,研究不同图像放大倍数下SRGAN的重构性能,采用峰值信噪比(PSNR)、结构相似性(SSIM)、孔隙度、分形维数和两点概率函数等对数字岩... 详细信息

以鄂尔多斯盆地延长组致密砂岩为研究对象,基于超分辨率生成对抗神经网络(SRGAN)提高数字岩心图像分辨率,研究不同图像放大倍数下SRGAN的重构性能,采用峰值信噪比(PSNR)、结构相似性(SSIM)、孔隙度、分形维数和两点概率函数等对数字岩心重构效果进行定量评价。研究结果表明,利用SRGAN重构的高分辨率图像在视觉效果上与原始CT图像非常接近,其峰值信噪比可以提高20 dB以上。随着放大倍数的增加,PSNR减小了约10 dB,SSIM减小了近一半,分形维数和孔隙度变化幅度不大。放大16倍的重构图像与原始图像的两点概率函数相差较大,图像失真较大,产生多余的伪影,不能作为后续图像重构基础。随后采用深度卷积生成对抗网络(DCGAN),实现了一维噪声数据到二维数字岩心图像重构,重构图像具有与原始CT图像相近的孔隙度、分形维数分布及连通性特征,但重构岩心图像的两点概率函数整体偏低,连通性较差。生成对抗神经网络可以用于提高数字岩心图像分辨率,实现数字岩心重构,在数字岩心研究领域具有广阔的应用前景。

关键词：数字岩心 CT图像生成对抗神经网络超分辨率重构致密砂岩

Flexible bidirectional pulse charging regulation achieving long-life lithium-ion batteries

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Journal of Energy Chemistry 2024年第9期96卷 59-71页

作者： Xiaodong Xu Shengjin Tang Xuebing Han Languang Lu Yudi Qin jiuyu Du Yu Wu Yalun Li Chuanqiang Yu Xiaoyan Sun Xuning Feng Minggao Ouyang Rocket Force University of Engineering Xi’an 710025ShaanxiChina State Key Laboratory of Intelligent Green Vehicle and Mobility School of Vehicle and MobilityTsinghua UniversityBeijing 100084China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

Typical application scenarios,such as vehicle to grid(V2G)and frequency regulation,have imposed significant long-life demands on lithium-ion ***,we propose an advanced battery life-extension method employing bidirectional pulse charging(BPC)*** traditional constant current charging methods,BPC strategy not only achieves comparable charging speeds but also facilitates V2G frequency regulation *** significantly enhances battery cycle ampere-hour throughput and demonstrates remarkable life extension *** this interesting conclusion,adopting model identification and postmortem characterization to reveal the life regulation mechanism of BPC:it mitigates battery capacity loss attributed to loss of lithium-ion inventory(LLI)in graphite anodes by intermittently regulating the overall battery voltage and anode potential using a negative charging ***,from the perspective of internal side reaction,the life extension mechanism is further revealed as inhibition of solid electrolyte interphase(SEI)and lithium dendrite growth by regulating voltage with a bidirectional pulse current,and a semi-empirical life degradation model combining SEI and lithium dendrite growth is developed for BPC scenarios health management,the model parameters are identified by genetic algorithm with the life simulation exhibiting an accuracy exceeding 99%.This finding indicates that under typical rate conditions,adaptable BPC strategies can extend the service life of LFP battery by approximately 123%.Consequently,the developed advanced BPC strategy offers innovative perspectives and insights for the development of long-life battery applications in the future.

关键词： Lithium-ion battery Long-life regulation Bidirectional pulse charging Mechanism identification