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Experimental and numerical interpretation on composite foundation consisting of soil-cement column within warm and ice-rich frozen soil

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Journal of Mountain Science 2024年第1期21卷 313-321页

作者： WANG Honglei ZHANG Jianming wei Shoucai sun Zhizhong ZHANG Hu School of Civil Engineering Hebei University of EngineeringHandan 056038China State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Second Geological Brigade Bureau of Geology and Mineral Resources Exploration and DevelopmentLhasa 850000China Da Xing’anling Observation and Research Station of Frozen Ground Engineering and Environment Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesJiagedaqi 165100China School of Civil Engineering Northeast Forestry UniversityHarbin 150040China

Affected by climate warming and anthropogenic disturbances, the thermo-mechanical stability of warm and ice-rich frozen ground along the Qinghai-Tibet engineering corridor(QTEC) is continuously decreased, which may delay the construction of major projects in the future. In this study, based on chemical stabilization of warm and icerich frozen ground, the soil-cement column(SCC) for ground improvement was recommended to reinforce the foundations in warm and ice-rich permafrost regions. To explore the validity of countermeasures mentioned above, both the original foundation and the composite foundation consisting of SCC with soil temperature of -1.0℃ were prepared in the laboratory, and then the plate loading tests were carried out. The laboratory investigations indicated that the bearing capacity of composite foundation consisting of SCC was higher than that of original foundation, and the total deformation of original foundation was greater than that of composite foundation, meaning that overall stability of foundation with warm and ice-rich frozen soil can be improved by SCC installation. Meanwhile, a numerical model considering the interface interaction between frozen soil and SCC was established for interpretating the bearing mechanism of composite foundation. The numerical investigations revealed that the SCC within composite foundation was responsible for the more applied load, and the applied load can be delivered to deeper zone in depth due to the SCC installation, which was favorable for improving the bearing characteristic of composite foundation. The investigations provide the valuable guideline for the choice of engineering supporting techniques to major projects within the QTEC.

关键词： Chemical stabilization Ground improvement Composite foundation Frozen soil engineering Qinghai-Tibet engineering corridor

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Spatiotemporal Characteristics of Rainfall over Different Terrain Features in the Middle Reaches of the Yangtze River Basin during the Warm Seasons of 2016–20

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Advances in Atmospheric Sciences 2024年第5期41卷 915-936页

作者： Qian wei Jianhua sun Shenming FU Yuanchun ZHANG Xiaofang WANG Key Laboratory of Cloud-Precipitation Physics and Severe Storms(LACS) Institute of Atmospheric PhysicsChinese Academy of Sciences(IAP/CAS)Beijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science and TechnologyNanjing 210044China University of Chinese Academy of Sciences Beijing 100029China International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Hubei Key Laboratory for Heavy Rian Monitoring and Warning Research Institute of Heavy RainChina Meteorological Administration(CMA)Wuhan 430205China

Based on hourly rain gauge data during May–September of 2016–20,we analyze the spatiotemporal distributions of total rainfall(TR)and short-duration heavy rainfall(SDHR;hourly rainfall≥20 mm)and their diurnal variations over the middle reaches of the Yangtze River *** all three types of terrain(i.e.,mountain,foothill,and plain),the amount of TR and SDHR both maximize in June/July,and the contribution of SDHR to TR(CST)peaks in August(amount:23%;frequency:1.74%).Foothill rainfall is characterized by a high TR amount and a high CST(in amount);mountain rainfall is characterized by a high TR frequency but a small CST(in amount);and plain rainfall shows a low TR amount and frequency,but a high CST(in amount).Overall,stations with high TR(amount and frequency)are mainly located over the mountains and in the foothills,while those with high SDHR(amount and frequency)are mainly concentrated in the foothills and plains close to mountainous *** all three types of terrain,the diurnal variations of both TR and SDHR exhibit a double peak(weak early morning and strong late afternoon)and a phase shift from the early-morning peak to the late-afternoon peak from May to *** the late-afternoon peak,the amount of TR and SDHR in the foothills is larger than over the mountains and *** TR intensity in the foothills increases significantly from midnight to afternoon,suggesting that thermal instability may play an important role in this process.

关键词： short duration heavy rainfall diurnal variation foothill rainfall

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Self-adaptive gas flow and phase change behaviors during hydrate exploitation by alternate injection of N2 and CO_(2)

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Petroleum Science 2024年第3期21卷 2120-2129页

作者： Bo-Jian Cao Yi-Fei sun Hong-Nan Chen Jin-rong Zhong Ming-Long Wang Ming Wang Chang-Yu sun Guang-Jin Chen State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China School of Chemistry and Chemical Engineering Changsha University of Science&TechnologyChangsha410114HunanChina

Since hydrate resources play a part of the stratigraphic framework structure in sediments,establishing a safe and economic method for hydrates exploitation remains the primary challenge to this *** the proposed methods,the spontaneous displacement of CH_(4) from hydrate cages by CO_(2) seems to be a perfect mechanism to address gas production and CO_(2) storage,especially in today's strong demand for carbon reduction and replacing clean *** extensive lab researches,in the past decade,injecting a mixture of CO_(2) and small molecule gas has become a key means to enhance displacement efficiency and has great potential for ***,there is a lack of in-depth research on gas flow in the reservoir,while the injected gas always passes through low-saturated hydrate areas with high permeability and then occurs gas channel in a short term,finally resulting in the decreases in gas production efficiency and produced gas ***,we explored a new injection-production mode of alternate injection of N2 and CO_(2) in order to fully coordinate the advantages of N2 in enhanced hydrate decomposition and CO_(2) in solid storage and heat *** alternate"taking"and"storing"processes perfectly repair the problem of the gas channel,achieving self-regulation effect of CH_(4) recovery and CO_(2) *** 3-D experimental results show that compared to the mixed gas injection,CH_(4) recovery is increased by>50%and CO_(2) storage is increased by>70%.Additionally,this alternate injection mode presented a better performance in CH_(4) concentration of produced gas and showed outstanding N2 utilization ***,we analyzed its self-adaptive gas flow mechanism and proposed an application model of"one injection and multiple production".We look forward to this study accelerating the application of CO_(2)-CH_(4) replacement technology.

关键词： Hydrate Replacement CH_(4) recovery CO_(2)storage Reservoir remediation

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Ferric ion-triggered surface oxidation of galena for efficient chalcopyrite-galena separation

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 261-267页

作者： Qiancheng Zhang Limin Zhang Feng Jiang Honghu Tang Li Wang wei sun School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Engineering Research Center of Ministry of Education for Carbon Emission Reduction in Metal Resource Exploitation and Utilization Changsha 410083China School of Resource and Environment Hunan University of Technology and BusinessChangsha 410083China

The efficient separation of chalcopyrite(CuFeS2)and galena(PbS)is essential for optimal resource ***,find-ing a selective depressant that is environmentally friendly and cost effective remains a *** various techniques,such as mi-croflotation tests,Fourier transform infrared spectroscopy,scanning electron microscopy(SEM)observation,X-ray photoelectron spec-troscopy(XPS),and Raman spectroscopy measurements,this study explored the use of ferric ions(Fe^(3+))as a selective depressant for *** results of flotation tests revealed the impressive selective inhibition capabilities of Fe^(3+)when used *** analysis showed that Fe^(3+)significantly reduced the adsorption of isopropyl ethyl thionocarbamate(IPETC)on the galena surface while having a minimal impact on *** analysis using SEM,XPS,and Raman spectra revealed that Fe^(3+)can oxidize lead sulfide to form compact lead sulfate nanoparticles on the galena surface,effectively depressing IPETC adsorption and increasing surface *** findings provide a promising solution for the efficient and environmentally responsible separation of chalcopyrite and galena.

关键词： galena chalcopyrite ferric ions flotation separation surface oxidation

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Cluster-Based Massive Access for Massive MIMO Systems

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China Communications 2024年第1期21卷 24-33页

作者： Shiyu Liang wei Chen Zhongwen sun Ao Chen Bo Ai State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong UniversityBeijing 100091China School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100091China Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong UniversityBeijing 100091China Key Laboratory of Railway Industry of Broadband Mobile Information Communications Beijing Jiaotong UniversityBeijing 100091China Beijing Engineering Research Center of High-speed Railway Broadband Mobile Communications Beijing Jiaotong UniversityBeijing 100091China School of Information Engineering Zhengzhou UniversityZhengzhou 450001China

Massive machine type communication aims to support the connection of massive devices,which is still an important scenario in *** this paper,a novel cluster-based massive access method is proposed for massive multiple input multiple output *** exploiting the angular domain characteristics,devices are separated into multiple clusters with a learned cluster-specific dictionary,which enhances the identification of active *** detected active devices whose data recovery fails,power domain nonorthogonal multiple access with successive interference cancellation is employed to recover their data via *** results show that the proposed scheme and algorithm achieve improved performance on active user detection and data recovery.

关键词： compressive sensing dictionary learning multiuser detection random access

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A method for active deception jamming discrimination based on frequency response

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Chinese Journal of Aeronautics 2024年第6期37卷 331-347页

作者： Wenbin wei Ruihui PENG Yunlong DONG Dianxing sun Le XU Guohong WANG Qingdao Innovation and Development Base of Harbin Engineering University Harbin Engineering University150001China Institute of Information Fusion Navy Aeronautical UniversityYantai 264001China

There are many types of radar active deception false target jamming that are highly correlated with the real *** the real and false targets under a low Signal-to-Noise Ratio(SNR)is *** solve the above problem,this article proposes a real/false target recognition method based on the features of multi-pulse joint frequency response by analyzing the differences in the scattering characteristics and modeling real target echoes as a synthesis of multi-scattering center ***,in the range-doppler domain,the real and false targets are truncated along the range dimension,and a fast Fourier transform is performed to extract the features of multi-pulse joint frequency ***,a two-channel feature fusion network is designed for real and false target ***,a Multi-Coherent Processing Interval Joint Decision Method(M-CPIJDM)based on temporal information is proposed to improve the recognition *** using the measured data show that the proposed method can well recognize real and false target signals under four jamming backgrounds:distance false target,velocity false target,distance-velocity composite false target,and forwarding dense false target.

关键词： Activedeception false target jamming Multi-scattering center echo Multi-pulse jointfrequency response feature Two-channelfeature fusion network Multi-coherent processing interval jointdecision

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Integrated Frequency-constrained Scheduling Considering Coordination of Frequency Regulation Capabilities from Multi-source Converters

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 261-274页

作者： Jiaming Li Ying Qiao Zongxiang Lu wei Ma Xin Cao rongfu sun the Department of Electrical Engineering Tsinghua UniversityBeijing 100084China the China suntien Green Energy Limited Company Shijiazhuang 050011China the State Grid Jibei Electric Power Company Beijing 100054China

As the proportion of renewable energy(RE)increases,the inertia and the primary frequency regulation(FR)capability of the power system ***,ensuring frequency security in the scheduling model has become a new technical requirement in power systems with a high share of *** to a shortage of conventional synchronous generators,the frequency support of multi-source converters has become an indispensable part of the system frequency resources,especially variable-speed wind turbine generation(WTG)and battery energy storage(BES).Quantitative expression of the FR capability of multi-source converters is necessary to construct frequency-constrained scheduling ***,the frequency support performance of these converter-interfaced devices is related to their working states,operation modes,and parameters,and the complex coupling of these factors has not been fully exploited in existing *** this study,we propose an integrated frequency-constrained scheduling model considering the coordination of FR capabilities from multi-source *** FR control strategies and variable FR parameters for WTG with or without reserved power are modeled,and multi-target allocation of BES capacity between tracking dispatch instruction and emergency FR is ***,the variable FR capabilities of WTG and BES are embedded into the integrated frequency-constrained scheduling *** nonlinear constraints for frequency security are precisely linearized through an improved iteration-based *** effectiveness of the proposed model is verified in a modified IEEE 24-bus standard *** results suggest that the coordinated participation of BES and WTG in FR can effectively reduce the cost of the scheduling model while meeting frequency security constraints.

关键词： Battery energy storage(BES) wind turbine generation(WTG) frequency regulation(FR) frequency security power system scheduling

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A novel seal-flow multi-vortex friction stir lap welding of metal to polymer matrix composites

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Chinese Journal of Aeronautics 2024年第1期37卷 451-462页

作者： Shuaiqiang NIAN Mingshen LI Shude JI wei HU Zhiqing ZHANG Zelin sun College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

The friction stir lap welding(FSLW)of metal to polymer is a challenging work due to the unavoidable polymer *** this problem,a novel seal-flow multi-vortex friction stir lap welding(SM-FSLW)technology based on the subversively-designed multi-step pin was put *** 7075 aluminum alloy and short glass fiber-reinforced polyether ether ketone(PEEK)as research subjects,the welding temperature,material flow,formation and tensile shear strength of dissimilar materials lap joint under the SM-FSLW were studied and compared with those under traditional FSLW based on the conical *** multi-step pin rather than the conical pin effectively hindered the polymer overflowing due to the formation of vortexes by the step,thereby attaining a joint with a smooth *** with traditional FSLW,the SMFSLW obtained the higher welding temperature,the more violent material flow and the larger area with high flow velocity,thereby producing the macro-mechanical and micro-mechanical interlockings and then heightening the joint loading *** tensile shear strength of lap joint under SM-FSLW was 27.8% higher than that under traditional *** SM-FSLW technology using the multi-step pin provides an effective way on obtaining a heterogeneous lap joint of metal to polymer with the excellent formation and high strength.

关键词： Friction stir lap welding Metal to polymer Multi-step pin Material flow Tensile shear strength

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Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane oxidation with molecular oxygen and the active sites investigation

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 101-112页

作者： Lei Chen Yuan sun Jinshan Chi wei Xiong Pingle Liu Fang Hao College of Chemical Engineering National&Local United Engineering Research Centre for Chemical Process Simulation and IntensificationXiangtan UniversityXiangtan411105China

The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol(KA oil)is a challenging issue in the chemical *** present the industrial conversion of cyclohexane to cyclohexanone and cyclohexanol is normally controlled at less than 5%***,the development of highly active and stable catalysts for the aerobic oxidation of cyclohexane is necessary to overcome this low-efficiency ***,we have developed a cobalt-nitrogen co-doped porous sphere catalyst,Co-NC-x(x is the Zn/Co molar ratio,where x=0,0.5,1,2,and 4)by pyrolyzing resorcinol-formaldehyde resin *** achieved 88.28%cyclohexanone and cyclohexanol selectivity and a cyclohexane conversion of 8.88%under *** results showed that the introduction of zinc effectively alleviated the aggregation of Co nanoparticles and optimized the structural properties of the *** addition,Co0 and pyridinic-N are proposed to be the possible active species,and their proportion efficiently increased in the presence of Zn^(2+)*** this study,we developed a novel strategy to design highly active catalysts for cyclohexane oxidation.

关键词： KA oil production cyclohexane selective oxidation cobalt-nitrogen co-doped porous carbon spheres metal-organic framework

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Synthesis of granulated Li_(1.33)Mn_(1.67)O_(4) via two antisolvent methods for lithium adsorption from gas-produced water

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Chinese Journal of Chemical Engineering 2024年第5期69卷 34-46页

作者： Jun Qiu Lu-Ri Bao wei Guo Ying Yang Shu-Ying sun National Engineering Research Center for Integrated Utilization of Salt Lake Resource East China University of Science and TechnologyShanghai 200237China

Gas-produced water is an accompanying wastewater in the natural gas extraction process,and it is a potential liquid lithium resource that contains a considerable amount of *** study investigated the feasibility of using manganese-based ion sieves to adsorb and extract lithium from gas-produced *** we focused on the applicability of two different granulation methods,extrusion and droplet,in gas-produced water *** types of H_(1.33)Mn_(1.67)O_(4) particles were prepared by the extrusion method(EHMO)and the droplet method(DHMO).The porosity of DHMO was much higher than that of EHMO,and the adsorption performance of DHMO increased with the decrease of binder *** prepared with a binder concentration of 0.14 g·ml^(-1)exhibited the best adsorption performance in gas-produced water,and the Li^(+)adsorption capacity could reach 25.14 mg·g^(-1).In gas-produced water,the adsorption equilibrium of DHMO only took 9 h,and the adsorption process conformed to the Langmuir model and pseudo-second-order kinetic *** pore diffusion model(PDM)could well describe its adsorption ***,DHMO showed a great selectivity to Li^(+),and the selectivity order of DHMO in gas-produced water was Li^(+)>Ba^(2+)>>Mg^(2+),Ca^(2+),Sr^(2+)>>Na^(+)>>K^(+).After 20 cycles,the Li^(+)adsorption capacity was still higher than 17.30 mg·g^(-1),and the rate of manganese dissolution was less than 1%.

关键词： Gas-produced water Granulation Li_(1.33)Mn_(1.67)O_(4)

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