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Occurrence of microplastics in natural and farmland soil in the Qilian Mountains of the Northern Tibetan Plateau

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Journal of Mountain Science 2024年第7期21卷 2159-2172页

作者： kang Qiangqiang ZHANG Yulan kang Shichang ZHANG Shengyin LUO Xi li Longrui wanG Zhaoqing ZHANG Shuncun Key Laboratory of Petroleum Resources Exploration and Evaluation Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China College of Earth and Environmental Sciences Lanzhou UniversityLanzhou 730000China

Microplastics(MPs)become ubiquitous in soil and are an environmental and public health concern ***,the status of MPs in natural and farmland soils in remote areas remains poorly *** this study,we investigated the characteristics of MPs in natural and farmland soils along two transects in the Qilian Mountains of the northern Tibetan *** average abundance of MPs in natural and farmland soils was 29,778 and 56,123 items kg^(-1),respectively,with a detection size range of 10-1000μ*** in the size range of 10-100μm accounted for 84.1%of particles *** the 21 polymers detected,polyethylene dominated in both farmland and natural *** shape of MPs was dominated by fragments(95.8%),followed by fibers(3.8%)and beads(0.4%).The abundance of MPs was positively correlated with increasing altitude in natural *** was no significant correlation between the abundance of MPs and soil physicochemical properties due to the narrow range of values of soil physicochemical *** the growing concern regarding MPs pollution,research on the status of MPs in high altitude and remote areas is critical to understanding their global cycle.

关键词： Microplastics pollution Soil Remote areas Tibetan Plateau

Experimental observations on the nonproportional multiaxial ratchetting of cast AZ91 magnesium alloy at room temperature

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1115-1125页

作者： Binghui Hu Yu Lei Hang li Ziyi wang Chao Yu Guozheng kang Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu 610031China

The nonproportional multiaxial ratchetting of cast AZ91 magnesium (Mg) alloy was examined by performing a sequence of axial-torsional cyclic tests controlled by stress with various loading paths at room temperature (RT).The evolutionary characteristics and path dependence of multiaxial ratchetting were *** illustrate that the cast AZ91 Mg alloy exhibits considerable nonproportional additional softening during cyclic loading with multiple nonproportional multiaxial loading paths;multiaxial ratchetting presents strong path dependence,and axial ratchetting strains are larger under nonproportional loading paths than under uniaxial and proportional45°linear loading paths;multiaxial ratchetting becomes increasingly pronounced as the applied stress amplitude and axial mean stress ***,stress-strain curves show a convex and symmetrical shape in axial/torsional *** ratchetting exhibits quasi-shakedown after certain loading *** abundant experimental data obtained in this work can be used to develop a cyclic plasticity model of cast Mg alloys.

关键词： cast magnesium alloy ratchetting multiaxial loading loading path stress level

Numerical modeling of fracture propagation of supercritical CO_(2)compound fracturing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2607-2628页

作者： Hao Chen Yong kang wanchun Jin Changhai li Can Cai School of Mechanical Engineering Southwest Petroleum UniversityChengdu610500China Laboratory of High-pressure Jet Theory and Application Technology Southwest Petroleum UniversityChengdu610500China Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan UniversityWuhan430072China Sinopec International Petroleum Exploration and Production Corporation Beijing 100029China

The exploitation of shale gas is promising due to depletion of the conventional energy and intensification of the greenhouse *** this paper,we proposed a heat-fluid-solid coupling damage model of supercritical CO_(2)(SC-CO_(2))compound fracturing which is expected to be an efficient and environmentally friendly way to develop shale *** coupling model is solved by the finite element method,and the results are in good agreement with the analytical solutions and fracturing *** on this model,the fracture propagation characteristics at the two stages of compound fracturing are studied and the influence of pressurization rate,in situ stress,bedding angle,and other factors are *** results show that at the SC-CO_(2)fracturing stage,a lower pressurization rate is conducive to formation of the branches around main fractures,while a higher pressurization rate inhibits formation of the branches around main fractures and promotes formation of the main *** bedding and in situ stress play a dominant role in the fracture *** the in situ stress ratio(δ_(x)/δ_(y))is 1,the presence of bedding can reduce the initiation pressure and failure ***,it will cause the fracture to propagate along the bedding direction,reducing the fracture *** rocks without bedding,hydraulic fracturing has the lengthening and widening effects for SC-CO_(2)induced *** shale,fractures induced at the hydraulic fracturing stage are more likely to be dominated by in situ stresses and have a shorter reorientation ***,fracture branches propagating along the maximum principal stress direction may be generated around the main fractures induced by SC-CO_(2)at the hydraulic fracturing *** the branches converge with the main fractures,fracture zones are easily formed,and thus the fracture complexity and damage area can be significantly *** results are instructive for the design and application of SC

关键词： Compound fracturing Fracture propagation Finite element method Damage evolution

Effects of long-term fencing on soil microbial community structure and function in the desert steppe,China

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Journal of Arid Land 2024年第3期16卷 431-446页

作者： PAN Yaqing kang Peng QU Xuan RAN Yichao li Xinrong Shapotou Desert Research and Experiment Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China School of Biological Science and Engineering North Minzu UniversityYinchuan 750021China

One of the goals of grazing management in the desert steppe is to improve its ***,relatively little is known about soil microbe communities in the desert steppe ecosystem under grazing *** this study,we investigated the diversity and aboveground biomass of Caragana korshinskii *** communities in long-term fencing and grazing areas,combined with an analysis of soil physical-chemical properties and genomics,with the aim of understanding how fence management affects plant-soil-microbial inter-relationships in the desert steppe,*** results showed that fence management(exclosure)increased plant diversity and aboveground biomass in *** shrub area and effectively enhanced soil organic carbon(233.94%),available nitrogen(87.77%),and available phosphorus(53.67%)*** well,the Shannon indices of soil bacteria and fungi were greater in the fenced ***-soil changes profoundly affected the alpha-and beta-diversity of soil *** management also altered the soil microbial community structure,significantly increasing the relative abundances of Acidobacteriota(5.31%-8.99%),Chloroflexi(3.99%-5.58%),and Glomeromycota(1.37%-3.28%).The soil bacterial-fungal co-occurrence networks under fence management had higher complexity and *** on functional predictions,fence management significantly increased the relative abundance of bacteria with nitrification and nitrate reduction functions and decreased the relative abundance of bacteria with nitrate and nitrite respiration *** relative abundances of ecologically functional fungi with arbuscular mycorrhizal fungi,ectomycorrhizal fungi,and saprotrophs also significantly increased under fence *** addition,the differential functional groups of bacteria and fungi were closely related to plant-soil *** results of this study have significant positive implications for the ecological restoration and reconstruction of dry desert steppe and simila

关键词： desert steppe fence management Caragana korshinskii soil physical-chemical property soil microorganism

Computer-aided diagnosis of Alzheimer’s disease based on structural magnetic resonance imaging

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Chinese Medical Journal 2024年第12期137卷 1483-1485页

作者： Yihang Huang Keyi Shan Yuzi Yan wan li School of Computer Science and Engineering Beijing Technology and Business UniversityBeijing 100048China

To the Editor:Alzheimer’s disease(AD)is an irreversible chronic neurodegenerative *** initially affects short-term memory,thinking,and *** then severely disrupts the normal lives of patients and their families and may eventually lead to *** cognitive impairment(MCI)is considered an early stage of *** studies have shown that nearly 20%of patients with MCI are at a risk of developing AD within the next four years.[1]Although there is no impressive way to stop the further development of MCI,only a series of procedures can slow ***,timely and accurate intervention is essential to effectively slow the disease progression.

关键词： diagnosis Alzheimer eventually

Broadband Dual-Input Doherty Power Amplifier Design Based on a Simple Adaptive Power Dividing Ratio Function

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China Communications 2024年第5期21卷 97-112页

作者： Dai Zhijiang Zhong kang li Mingyu Pang Jingzhou Jin Yi School of Microelectronics and Communication Engineering Chongqing UniversityChongqing 400044China Xi’an Branch of China Academy of Space Technology Xi’an 710100China

In this paper,a simple adaptive power dividing function for the design of a dual-input Doherty power amplifier(DPA)is *** the presented approaches,the signal separation function(SSF)at different frequency points can be characterized by a *** in the practical test,the coefficients of SSF can be determined by measuring a small number of data points of input *** as other dualinput DPAs,the proposed approach can also achieve high output power and back-off efficiency in a broadband operation band by adjusting the power distribution ratio ***,a 1.5-2.5 GHz highefficiency dual-input Doherty power amplifier is implemented according to this *** test results show that the peak power is 48.6-49.7d Bm,and the 6-d B back-off efficiency is 51.0-67.0%,and the saturation efficiency is 52.4-74.6%.The digital predistortion correction is carried out at the frequency points of 1.8/2.1GHz,and the adjacent channel power ratio is lower than-54.5d *** and experiment results can verify the effectiveness and correctness of the proposed method.

关键词： broadband doherty power amplifier dualinput efficiency enhancement load modulation

Experimental study on secondary air mixing along the bed height in a circulating fluidized bed with a multitracer-gas method

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Chinese Journal of Chemical Engineering 2024年第6期70卷 54-62页

作者： Qingyu Zhang Leming Cheng Kun li Qixun kang Qiang Guo Chaogang Wu Institute for Thermal Power Engineering State Key Laboratory of Clean Energy UtilizationZhejiang UniversityHangzhou 310027China Dongfang Boiler Group Co.Ltd. Zigong 643001China

A multitracer-gas method was proposed to study the secondary air(SA)mixing along the bed height in a circulating fluidized bed(CFB)using carbon monoxide(CO),oxygen(O_(2)),and carbon dioxide(CO_(2))as tracer *** were carried out on a cold CFB test rig with a cross-section of 0.42 m×0.73 m and a height of 5.50 *** effects of superficial velocity,SA ratio,bed inventory,and particle diameter on the SA mixing were *** results indicate that there are some differences in the measurement results obtained using different tracer gases,wherein the deviation between CO and CO_(2) ranges from 42%to 66%and that between O_(2) and CO_(2) ranges from 45%to 71%in the lower part of the fluidized ***,these differences became less pronounced as the bed height ***,the high solid concentration and fine particle diameter in the CFB may weaken the *** measurement results of different tracer gases show the same trends under the variation of operating *** superficial velocity and SA ratio and decreasing particle diameter result in better mixing of the *** effect of bed inventory on SA mixing is not monotonic.

关键词： Circulating fluidized bed Secondary air injection Gas mixing Multitracer-gas method

Ferritinophagy: A new idea for liver diseases regulated by ferroptosis

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Hepatobiliary & Pancreatic Diseases International 2024年第2期23卷 160-170页

作者： Zi-Bing Qian Jun-Feng li wan-Yuan Xiong Xiao-Rong Mao The First Clinical Medical College of Lanzhou University Lanzhou 730000China Institute of Infectious Diseases The First Hospital of Lanzhou UniversityLanzhou 730000China Department of Infectious Disease The First Hospital of Lanzhou UniversityLanzhou 730000China

Background:The discovery of regulatory cell death has led to a breakthrough in the therapeutic *** forms of cell death,such as necrosis,apoptosis,pyroptosis,autophagy,and ferroptosis,play an important role in the development of liver *** general,more than one form of cell death pathways is responsible for the disease ***,it is particularly important to study the regulation and interaction of various cell death forms in liver *** sources:We performed a PubMed search up to November 2022 with the following keywords:ferritinophagy,ferroptosis,and liver *** also used terms such as signal path,inducer,and inhibitor to supplement the query ***:This review summarized the basic characteristics of ferritinophagy and ferroptosis and the regulation of ferroptosis by ferritinophagy and reviewed the key targets and treatment strategies of ferroptosis in different liver ***:Ferritinophagy is a potential therapeutic target in ferroptosis-related liver diseases.

关键词： Ferritinophagy Ferroptosis liver disease

2D–3D dual carbon layer confined ultrasmall VN nanoparticles for improving lithium-ion storage in hybrid capacitors

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Rare Metals 2024年第1期43卷 65-75页

作者： Zhao-Wei Hu Hui-Fang li Peng wang wan-li wang Lei Yang Xiao-Jun wang Zhi-Ming liu College of Electromechanical Engineering Shandong Engineering Laboratory for Preparation and Application of High-Performance Carbon-MaterialsQingdao University of Science&TechnologyQingdao 266061China Research Center for Intelligent and Wearable Technology College of Textiles and ClothingQingdao UniversityQingdao 266071China

lithium-ion capacitors(liCs) of achieving high power and energy density have garnered significant attention. However, the kinetics unbalance between anode and cathode can impede the application of liCs. Vanadium nitride(VN) with a high theoretical specific capacity(~ 1200 m Ah·g^(-1)) is a better pseudocapacitive anode to match the response of cathode in liCs. However, the insertion/extraction of li-ions in VN's operation results in significant volume expansion. Herein, the VN/N-r GO-5composite that three-dimentional(3D) dicyandiamidederived-carbon(DDC) tightly wrapped VN quantum dots(VN QDTs) on two-dimentional(2D) reduced graphene oxid(r GO) was prepared by a facile strategy. The VN QDTs can reduce ion diffusion length and improve charge transfer kinetics. The 2D r GO as a template provides support for nanoparticle dispersion and improves electrical conductivity. The 3D DDC tightly encapsulated with VN QDTs mitigates agglomeration of VN particles as well as volume expansion. Correspondingly, the liCs with VN/Nr GO-5 composite as anode and activated carbon(AC) as cathode were fabricated, which exhibits a high energy density and power density. Such strategy provides a perspective for improving the electrochemical properties of liC anode materials by suppressing volume expansion and enhancing conductivity.

关键词： Vanadium nitride(VN)quantum dots Reduced graphene oxide(rGO)nanosheets Dicyandiamide-derived-carbon 2D–3D dual carbon layer lithium-ion capacitors