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Steel-refractory reactions in lanthanum-,cerium-,and ytrium-added steels

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Journal of Iron and Steel Research International 2024年第6期31卷 1473-1485页

作者： jian kang Hong-po Wang yu Wang College of Materials Science and Engineering Chongqing UniversityChongqing 400044China The State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China

A systematic experimental study was conducted on the similarities and differences in the reactions between commonly used rare earth elements(REEs)and frequently used refractories in the steelmaking *** results indicate that the reaction behaviors of La,Ce,and Y with MgO,Al_(2)O_(3),and MgO·Al_(2)O_(3) crucibles differed *** consumption rates of La,Ce,and Y in the molten steel were in descending order of La>Ce>Y for smelting with all three kinds of *** the REEs reacted with the crucible,the contents of Mg and Al showed a trend of first increasing and then *** laboratory-scale smelting conditions,the reactions related to REEs were dominated by steel-crucible reactions,and the contact area between the unit mass of molten steel and refractory materials mainly determined the consumption rates of ***-and Ce-crucible reactions generated loose and porous reaction interfaces;however,Y-crucible reactions generated a dense Y_(2)O_(3) layer,dramatically suppressing the consumption rate of *** calculation indicated that the reactions between rare earth and different refractory materials were first-order *** crucible materials significantly affected the product type and morphology of the steel-crucible reaction interfaces,thereby influencing the consumption rate of *** reactions between REEs and refractories must be seriously considered,especially for small-scale smelting.

关键词： Rare earth Inclusion Refractory Thermodynamics Dynamics

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磁力可开关的永磁轮设计与优化

机械工程与自动化 2024年第1期 105-107页

作者：张博洋冯永利于健康华北理工大学机械工程学院河北唐山063000

为解决爬壁机器人的永磁轮吸附力无法改变、作业完成后很难从壁面取下的问题,设计了一种磁力可开关的永磁轮。采用Maxwell软件对永磁轮的吸附单元进行了参数化优化设计,使得爬壁机器人的永磁轮能以较小的质量提供400 N左右的吸力,并能... 详细信息

为解决爬壁机器人的永磁轮吸附力无法改变、作业完成后很难从壁面取下的问题,设计了一种磁力可开关的永磁轮。采用Maxwell软件对永磁轮的吸附单元进行了参数化优化设计,使得爬壁机器人的永磁轮能以较小的质量提供400 N左右的吸力,并能关闭磁力以便工作人员将爬壁机器人从壁面分离。

关键词：永磁吸附磁力仿真优化设计爬壁机器人

Autonomous multi-drone racing method based on deep reinforcement learning

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Science China(Information Sciences) 2024年第8期67卷 35-48页

作者： yu kang jian DI Ming LI yunbo ZHAO yuhui WANG Department of Automation University of Science and Technology of China Institute of Advanced Technology University of Science and Technology of China Institute of Artificial Intelligence Hefei Comprehensive National Science Center College of Automation Engineering Nanjing University of Aeronautics and Astronautics

Racing drones have attracted increasing attention due to their remarkable high speed and excellent maneuverability. However, autonomous multi-drone racing is quite difficult since it requires quick and agile flight in intricate surroundings and rich drone interaction. To address these issues, we propose a novel autonomous multi-drone racing method based on deep reinforcement learning. A new set of reward functions is proposed to make racing drones learn the racing skills of human experts. Unlike previous methods that required global information about tracks and track boundary constraints, the proposed method requires only limited localized track information within the range of its own onboard sensors. Further, the dynamic response characteristics of racing drones are incorporated into the training environment, so that the proposed method is more in line with the requirements of real drone racing scenarios. In addition, our method has a low computational cost and can meet the requirements of real-time racing. Finally, the effectiveness and superiority of the proposed method are verified by extensive comparison with the state-of-the-art methods in a series of simulations and real-world experiments.

关键词： racing drone autonomous multi-drone racing sim-to-real deep reinforcement learning Markov game

CO_(2)flooding in shale oil reservoir with radial borehole fracturing for CO_(2)storage and enhanced oil recovery

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Petroleum Science 2024年第1期21卷 519-534页

作者： Jia-Cheng Dai Tian-yu Wang Jin-Tao Weng kang-jian Tian Li-Ying Zhu Gen-Sheng Li State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China China National Oil and Gas Exploration and Development Company Limited Beijing100034China

This study introduces a novel method integrating CO_(2)flooding with radial borehole fracturing for enhanced oil recovery and CO_(2)underground storage,a solution to the limited vertical stimulation reservoir volume in horizontal well fracturing.A numerical model is established to investigate the production rate,reservoir pressure field,and CO_(2)saturation distribution corresponding to changing time of CO_(2)flooding with radial borehole fracturing.A sensitivity analysis on the influence of CO_(2)injection location,layer spacing,pressure difference,borehole number,and hydraulic fractures on oil production and CO_(2)storage is *** CO_(2)flooding process is divided into four *** in layer spacing will significantly improve oil production rate and gas storage ***,serious gas channeling can occur when the spacing is lower than 20 *** the pressure difference between the producer and injector,the borehole number,the hydraulic fracture height,and the fracture width can also increase the oil production rate and gas storage *** analysis shows that layer spacing and fracture height greatly influence gas storage and oil *** outcomes are expected to provide a theoretical basis for the efficient development of shale oil reservoirs in the vertical direction.

关键词： Shale oil Radial borehole fracturing Embedded discrete fracture model Enhanced oil recovery Carbon storage

A new liquid membrane diffusion model for characterizing the adsorption kinetics of europium by using a continuous measurement of adsorption platform

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Nuclear Science and Techniques 2024年第1期35卷 59-72页

作者： Hao-Qi yu Tao yu jian-Hua Ye State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China CGN Cangnan Nuclear Power Co. Ltd.Cangnan 325800China jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices East China University of TechnologyNanchang 330013China School of Nuclear Science and Engineering East China University of TechnologyNanchang 330013China

To explore the kinetic adsorption under continuous and nonequilibrium states, an integration of continuous measurement and adsorption platform kinetics method was proposed, which was initially called the ICM-AP kinetics method, and a corresponding kinetic adsorption experimental method was developed. Adsorption experiments of europium(Eu) on Ca-bentonite,Na-bentonite, and the D231 cation exchange resin were performed using the ICM-AP kinetics method and continuous measurements. Because the kinetic experimental results observed in this study were different from those of traditional batch adsorption data, pseudo-first-order or pseudo-second-order kinetic models were unsuitable for fitting the experimental ***, a liquid membrane diffusion(LMD) model was developed based on the assumption of simultaneous adsorption/desorption to discuss the mechanism of kinetic adsorption. The kinetic adsorption mechanism was also studied by using *** results indicated that the proposed adsorption model can fit the experimental data more suitably, and the adsorption/desorption behaviors of Eu on bentonite and the D231 resin were simultaneously observed, suggesting that the adsorption kinetics of Eu(Ⅲ) was mainly dominated by hydrated Eu(Ⅲ) ions on the liquid membrane.

关键词： ICM-AP method LMD model Adsorption mechanism Eu(Ⅲ)

Recent progress in self-propelled particles

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Journal of Hydrodynamics 2024年第1期36卷 61-77页

作者： Zhen-yu Ouyang jian-zhong Lin Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo315201China Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou310027China

Self-propelled particles are commonly found in a large number of planktonic organisms such as bacteria,fungi,and algae in nature,and researchers have taken a long interest in exploring their swimming mechanisms for more than a *** in the past 20 years,with the development of computational fluid dynamics and flow display technology,as well as the need for the design of synthetic self-propelled particles and micro-swimming devices,self-propelled particles have become the forefront and hotspot of current research in the field of fluid *** paper first introduces the swimming characteristics of common self-propelled particles,leading to a classic“squirmer”type self-propelled particle *** this basis,a systematic introduction and summary of the theoretical and numerical simulation research of“squirmer”will be ***,the main challenges and opportunities faced by the current research will be summarized.

关键词： Self-propelled particles multiphase flow hydrodynamic interaction

Short-term effects of supplementary feeding with enteral nutrition via jejunostomy catheter on post-gastrectomy gastric cancer patients

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Chinese Medical Journal 2011年第20期124卷 3297-3301页

作者： WU Quan yu jian-chun kang Wei-ming MA Zhi-qiang Department of General Surgery Peking Union Medical College Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100730 China

Background Most gastric cancer patients who undergo gastrectomy develop malnutrition. It is, therefore, crucial to establish an effective means to provide nutrition for these patients. To perform home enteral nutrition （EN） to ensure adequate nutritional intake in gastric cancer patients, we placed a jejunostomy catheter during gastric surgery. Most patients showed improved nutritional status. Methods Twenty-nine inpatients at our hospital underwent radical gastrectomy and jejunostomy from December 2002 to December 2007 and were designated as the jejunostomy group, and 32 matched patients without a jejunostomy tube were designated as the tube-free group. The jejunostomy group was treated with EN from 72 hours to 3 months postoperatively. The tube-free group did not receive EN. Data including preoperative and postoperative body weight, body mass index （BMI）, nutrition risk screening （NRS） score, Karnofsky performance score （KPS）, and laboratory biochemical indicators were documented respectively and compared. Results Compared with preoperative week 1, both groups showed decreased body weight and BMI at 3 months postoperatively. The weight loss in the jejunostomy group （（7.1±3.3） kg） was significantly less than that in the tube-free group （（9.9±3.1） kg）. Similarly, BMI decreased by （2.4±1.0） kg/m2 in the jejunostomy group, which was significantly less than in the tube-free group （（3.2±0.9） kg/m2）. The number of patients with postoperative NRS 〉3 was decreased in the jejunostomy group, but was increased in the tube-free group, and this difference was significant. There were no significant differences between the two groups in total lymphocyte count, hemoglobin, albumin and prealbumin, and adverse drug effects. Conclusions Short-term （3 months） EN supplementation via jejunostomy tube can reduce the risk of malnutrition and weight loss, and improve tolerance of chemotherapy. Tube feeding is reliable for achieving these goals because it is not important whether or not the

关键词： malnutrition gastric cancer gastrectomy postoperative period jejunostomy catheter home enteral nutrition

Direct numerical simulation of shock wave/boundary layer interaction controlled by steady microjet in a compression ramp

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Chinese Journal of Aeronautics 2024年第10期37卷 83-102页

作者： Ruoye XIAO Dong SUN jian yu School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Aerodynamics Mianyang 621000China

Shock wave/boundary layer interaction in a 24°turning angle of the compression ramp at Mach number 2.9 controlled by steady microjet is investigated using direct numerical *** different jet spacings which are termed as sparse,moderate and dense are considered,and the induced vortex system and shock structures are compared.A moderate jet spacing configuration is found to generate counter-rotating vortex pairs that transport high-momentum fluid towards the vicinity of wall and strengthen the boundary layer to resist separation,reducing the separation *** dense jet spacing configuration creates a larger momentum deficit region,reducing the friction downstream of the *** of pressure and pressure gradient reveals that dense jet spacing configuration reduces the intensity of separation *** impact of varying jet spacings on the turbulent kinetic energy transport mechanism is also investigated by decomposing the budget terms in the transport ***,the spectral characteristics of the separation region are studied using power spectral density and dynamic mode decomposition methods,revealing that moderate jet spacing configuration suppresses low-frequency fluctuations in the separation region.

关键词： Shock wave/boundary layer interaction Compression ramp Steady microjet Different jet spacings Direct numerical simulation

Tuning Surface Molecular Design of Porous Carbon for Blue Energy Harvesting

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Research 2024年第1期2023卷 651-662页

作者： jian yu Zhong-Lin Wang Tianwei Ma Department of Civil and Environmental Engineering University of Hawaii at MānoaHonoluluHI 96822USA Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China College of Engineering Texas A&M University-Corpus ChristiCorpus ChristiTX 78412USA

Capacitive mixing is a promising blue energy technology due to its membrane-free electricity generation and long electrode life ***,because of limited performance,existing systems do not lend themselves to practical *** it is a crucial factor directly influencing electrode behavior,surface chemistry has largely been overlooked in capacitive ***,we show that manipulating surface functionalization alone can tune the responses of electrodes to produce a high voltage rise without altering the pore structure of the *** findings reveal that the spontaneous electrode potential of a surface-modified carbon electrode shifts negatively proportional to the surface charge due to the surface groups,which explains why and how manipulating the surface chemistry can improve the power generation capacity.

关键词： electrode Porous mixing