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Gravel hardness effect on compaction characteristics of gravelly soil

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Journal of Mountain Science 2024年第4期21卷 1432-1443页

作者： SHI Yunfang LI Shengang jiang chen LIU Jinning School of Resources and Civil Engineering Northeastern UniversityShenyang 110004China

The compaction characteristics of gravelly soil are affected by gravel *** investigate the evolution and influencing mechanism of different gravel hardness on the compaction characteristics of gravelly soil,heavy compaction tests and crushing tests were conducted on gravelly soils with gravels originated from hard,soft and extremely soft *** to orthogonal experiments and variance analysis,it was found that hardness has a significant impact on the maximum dry density of gravelly soil,followed by gravel content,and lastly,moisture *** gravel compositions with an average saturated uniaxial compressive strength less than 60 MPa,the order of compacted maximum dry density is soft gravels>hard gravels>extremely soft *** type of gravelly soil has a threshold for gravel content,with 60%for hard and soft gravels and 50%for extremely soft *** these thresholds,the compacted dry density decreases *** is a certain interaction between hardness,gravel content,and moisture *** hardness increases the influence of gravel content,whereas lower hardness increases the influence of moisture *** soils with the coarse aggregate(CA)between 0.7 and 0.8 typically achieve higher dry densities after *** addition,the prediction equations for the particle breakage rate and CA ratio in the Bailey method were proposed to estimate the compaction performance of gravelly soil *** results further revealed the compaction mechanism of different gravelly soils and can provide reference for subgrade filling construction.

关键词： Gravelly soil Hardness Compaction characteristics Crushing characteristics Particle breakage rate Bailey method

Advanced nano-based strategies for mRNA tumor vaccine

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Acta Pharmaceutica Sinica B 2024年第1期14卷 170-189页

作者： Yangqi Qu Jingjing Xu Tong Zhang Qinjun chen Tao Sun chen jiang Key Laboratory of Smart Drug Delivery(Ministry of Education) Minhang HospitalState Key Laboratory of Medical NeurobiologyDepartment of PharmaceuticsSchool of PharmacyFudan UniversityShanghai 201203China

Tumor vaccine is a promising strategy for cancer immunotherapy by introducing tumor antigens into the body to activate specific anti-tumor immune *** with the technological breakthroughs in genetic engineering and delivery systems,messenger ribonucleic acid(mRNA)technology has achieved unprecedented development and application over the last few years,especially the emergency use authorizations of two mRNA vaccines during the COVID-19 pandemic,which has saved countless lives and makes the world witness the powerful efficacy of mRNA technology in ***,unlike infectious disease vaccines,which mainly induce humoral immunity,tumor vaccines also need to activate potent cellular immunity to control tumor growth,which creates a higher demand for mRNA delivery to the lymphatic organs and antigen-presenting cells(APCs).Here we review the existing bottlenecks of mRNA tumor vaccines and advanced nano-based strategies to overcome those challenges,as well as future considerations of mRNA tumor vaccines and their delivery systems.

关键词： mRNA vaccine Nanoparticle Tumor vaccine Delivery system Stability Targeting Transfection Immunogenicity

Numerical and Experimental Analysis of the Aerodynamic Torque for Axle-Mounted Train Brake Discs

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Fluid Dynamics & Materials Processing 2024年第8期20卷 1867-1882页

作者： Nan Liu chen Hong Xinchao Su Xing Jin chen jiang Yuqi Shi Bingkun Wang Brake System Laboratory CRCC(Qingdao)Vehicle Inspection Station Co.Ltd.Qingdao266031China Brake System Laboratory CRRC Qingdao Sifang Rolling Stock Research Institute Co.Ltd.Qingdao266031China The State Key Laboratory of Heavy-Duty and Express High-Power Electric Locomotive Central South UniversityChangsha410075China Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic&Transportation EngineeringCentral South UniversityChangsha410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle Changsha410075China

As the velocity of a train increases,the corresponding air pumping power consumption of the brake discs increases *** the present experimental study,a standard axle-mounted brake disc with circumferential pillars was analyzed using a 1:1 scale model and a test rig in a wind *** particular,three upstream velocities were selected on the basis of earlier investigations of trains operating at 160,250,and 400 km/h,***,3D steady computational fluid dynamics(CFD)simulations of the flow field were conducted to compare with the wind tunnel test *** results for a 3-car train at 180 km/h demonstrated:(1)good agreement between the air resistance torques obtained from the wind tunnel tests and the related numerical results,with differences ranging from 0.95%to 5.88%;(2)discrepancies ranging from 3.2 to 3.8 N·m;(3)cooling ribs contributing more than 60%of the air resistance torque;(4)the fast rotation of brake discs causing a significantly different flow field near the bogie area,resulting in 25 times more air pumping power loss than that obtained in the stationary brake-disc case.

关键词： Axle-mounted train brake disc aerodynamic torque wind tunnel test numerical simulation

Cellular atlases of ovarian microenvironment alterations by diet and genetically-induced obesity

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Science China(Life Sciences) 2024年第1期67卷 51-66页

作者： Yonghui jiang Xueying Gao Yue Liu Xueqi Yan Huangcong Shi Rusong Zhao Zi-jiang chen Fei Gao Han Zhao Shigang Zhao Center for Reproductive Medicine Shandong UniversityJinan 250012China Research Unit of Gametogenesis and Health of ART-Offspring Chinese Academy of Medical Sciences(No.2021RU001)Jinan 250012China Key Laboratory of Reproductive Endocrinology of Ministry of Education Shandong UniversityJinan 250012China Shandong Key Laboratory of Reproductive Medicine Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250012China Shandong Provincial Clinical Research Center for Reproductive Health Jinan 250012China National Research Center of Assisted Reproductive Technology and Reproductive Genetics Shandong UniversityJinan 250012China The Affiliated Suzhou Hospital of Nanjing Medical University Suzhou Municipal HospitalGusu SchoolNanjing Medical UniversitySuzhou 215000China Center for reproductive medicine Ren Ji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200127China Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics Shanghai 200127China State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of ScienceBeijing 100101China

Obesity,which can arise from genetic or environmental factors,has been shown to cause serious damages to the reproductive *** ovary,as one of the primary regulators of female fertility,is a complex organ comprised of heterogeneous cell types that work together to maintain a normal ovarian microenvironment(OME).Despite its importance,the effect of obesity on the entire ovary remains poorly *** this study,we performed ovary single-cell and nanoscale spatial RNA sequencing to investigate how the OME changed under different kinds of obesity,including high-fat diet(HFD)induced obesity and Leptin ablation induced obesity(OB).Our results demonstrate that OB,but not HFD,dramatically altered the proportion of ovarian granulosa cells,theca-interstitial cells,luteal cells,and endothelial ***,based on the spatial dynamics of follicular development,we defined four subpopulations of granulosa cell and found that obesity drastically disrupted the differentiation of mural granulosa cells from small to large antral ***,HFD enhanced follicle-stimulating hormone(FSH)sensitivity and hormone conversion,while OB caused decreased sensitivity,inadequate steroid hormone conversion,and impaired follicular *** differences can be explained by the differential expression pattern of the transcription factor ***,our study provides a powerful and high-resolution resource for profiling obesity-induced OME and offers insights into the diverse effects of obesity on female reproductive disorders.

关键词： obesity ovarian microenvironment snRNA-seq Stereo-seq Foxo1

Novel Batch Polishing Method of Ceramic Cutting Inserts for Reducing Tool Wear

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 74-83页

作者： Rui Gao Chunjin Wang Yee Man Loh Xiaoliang Liang chen jiang Chi Fai Cheung State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong Kong 999077China College of Mechanical Engineering University of Shanghai for Science and TechnologyShanghai 200093China

Ceramic cutting inserts are a type of cutting tool commonly used in high-speed metal cutting ***,the wear of these inserts caused by friction between the workpiece and cutting inserts limits their overall *** order to improve the tool life and reduce wear,this study introduces an emerging method called magnetic field-assisted batch polishing(MABP)for simultaneously polishing multiple ceramic cutting *** polishing experiments were conducted under different conditions,and the wear characteristics were clarified by cutting S136H *** results showed that after 15 min of polishing,the surface roughness at the flank face,edge,and nose of the inserts was reduced to below 2.5 nm,6.25 nm,and 45.8 nm,***,the nose radii of the inserts did not change significantly,and there were no significant changes in the weight percentage of elements before and after ***,the tool life of the batch polished inserts was found to be up to 1.75 times longer than that of unpolished *** findings suggest that the MABP method is an effective way to mass polish ceramic cutting inserts,resulting in significantly reduced tool ***,this novel method offers new possibilities for polishing other tools.

关键词： Polishing Finishing Magnetic field-assisted Tool wear Ultra-precision machining

Miyaoka-type inequalities for terminal threefolds with nef anti-canonical divisors

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Science China Mathematics 2024年

作者： Masataka Iwai chen jiang Haidong Liu Department of Mathematics Graduate School of Science Osaka University Shanghai Center for Mathematical Sciences & School of Mathematical Sciences Fudan University Department of mathematics Sun Yat-sen University

In this paper,we study Miyaoka-type inequalities on Chern classes of terminal projective 3-folds with nef anti-canonical *** X be a terminal projective 3-fold such that-KXis *** show that if c1（X）·c2（X）≠0,then c1（X）·c2（X）≥1/252;if further X is not rationally connected,then c1（X）·c2（X）≥4/5 and this inequality is *** order to prove this,we give a partial classification of such varieties along with many *** also study the nonvanishing of c1（X）dimX-2·c2（X） for terminal weak Fano varieties and prove a Miyaoka-Kawamata-type inequality.

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Fracturing-flooding technology for low permeability reservoirs:A review

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Petroleum 2024年第2期10卷 202-215页

作者： Nianyin Li Shijie Zhu Yue Li Jingrui Zhao Bo Long Fei chen Erzhen Wang Wentao Feng Yanan Hu Shubei Wang chen jiang State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China CNPC Southwest Oil and Gas Field Company Exploration and Development Research Institute Chengdu 610051China CNPC Southwest Oil and Gas Field Company Shale Gas Research Institute Chengdu 610051China Western Drilling Tuha Underground Operation Company Turpan838200China Changqing Downhole Technical Service Company of Chuanqing Drilling Engineering Co. Ltd.CNPCXi’anChina Petroleum Technology Research Institute Petrochina Changqing Oilfield CompanyXi'anChina

The development of low-permeability oil and gas resources presents a significant challenge to traditional development *** address the problem of“no injection and no production”in low-permeability reservoirs,a novel fracture-injection-production integration technology named fracturing-flooding has been proposed by oilfield *** technology combines the advantages of conventional fracturing,water flooding,and chemical flooding,resulting in improved reservoir physical properties,increased injection,replenished energy,and increased oil displacement *** technology is especially suitable for low-permeability reservoirs that suffer from lack of energy,and strong ***-flooding technology has shown significant results and broad development prospects in some oilfields in *** paper analyzes the development status of fracturing-flooding technology from its development history,technical mechanism,technical characteristics,process flow,types of fracturing and oil displacement fluids,and field *** and numerical simulations of fracturingflooding technology are also *** results suggest that fracturing-flooding technology is more effective than conventional fracturing,water flooding,and chemical flooding in stimulating lowpermeability tight reservoirs and improving oil ***,it has a high input-output ratio and can be utilized for future reservoir stimulation and transformation.

关键词： Fracturing-flooding Enhanced oil recovery Low permeability reservoirs Water flooding Injection Chemical flooding Fracturing

Effect of short-time low-temperature austenitizing on microstructure and mechanical properties of DT300 ultra-high strength steel fabricated by laser powder bed fusion

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Journal of Iron and Steel Research International 2024年第7期31卷 1763-1777页

作者： chen-yang jiang Xiao-qiang Li Jin-tao Wang Hao Luo Sheng-qing Gao Sheng-guan Qu Chao Yang National Engineering Research Centre of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640GuangdongChina Institute of New Materials Guangdong Academy of ScienceGuangzhou 510650GuangdongChina

To address the inhomogeneous microstructure and improve the mechanical properties of DT300 ultra-high strength steel specimens fabricated by laser powder bed fusion,different post-heat treatment schedules are *** the increase in austenitizing temperature and time,the migration rate of austenite grain boundaries continuously increases with the dissolution of nano-carbides,and the formation of nano-oxides and twin martensite is also inhibited *** rapid growth in the size of prior austenite grains and martensite laths,as well as the decrease in the content of nano-oxides and twin martensite,led to a rapid decrease in the strength(yield strength and ultimate tensile strength)from HT2 to HTF *** HT1 specimens(austenitizing at 830℃for 30 min,then oil quenching and tempering at 300℃for 120 min and finally air cooling)display excellent mechanical properties of yield strength of 1572 MPa,ultimate tensile strength of 1847 MPa,elongation of 9.84%,and fracture toughness of 106 MPa m^(1/2),which are counterparts to those of conventional DT300 steel forgings after heat treatment.

关键词： DT300 ultra-high strength steel Laser powder bed fusion-Short-time low-temperature austenitizing Microstructure Mechanical property

Allelic reprogramming of chromatin states in human early embryos

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National Science Review 2024年第3期11卷 58-71页

作者： Shenli Yuan Lei Gao Wenrong Tao Jianhong Zhan Gang Lu Jingye Zhang Chuanxin Zhang Lizhi Yi Zhenbo Liu Zhenzhen Hou Min Dai Han Zhao Zi-jiang chen jiang Liu Keliang Wu Center for Reproductive Medicine Shandong University CAS Key Laboratory of Genome Sciences and Information Collaborative Innovation Center of Genetics and Development Beijing Institute of Genomicsand China National Center for BioinformationChinese Academy of Sciences University of Chinese Academy of Sciences CUHK-SDU Joint Laboratory on Reproductive Genetics School of Biomedical Sciences the Chinese University of Hong Kong Key Laboratory of Reproductive Endocrinology of the Ministry of Education Shandong University Center for Reproductive Medicine Ren Ji Hospital School of Medicine Shanghai Jiao Tong University CAS Center for Excellence in Animal Evolution and Genetics Chinese Academy of Sciences

The reprogramming of parental epigenomes in human early embryos remains elusive. To what extent the characteristics of parental epigenomes are conserved between humans and mice is currently unknown. Here,we mapped parental haploid epigenomes using human parthenogenetic and androgenetic embryos. Human embryos have a larger portion of genome with parentally specific epigenetic states than mouse *** allelic patterns of epigenetic states for orthologous regions are not conserved between humans and mice. Nevertheless, it is conserved that maternal DNA methylation and paternal H3K27me3 are associated with the repression of two alleles in humans and mice. In addition, for DNA-methylation-dependent imprinting, we report 19 novel imprinted genes and their associated germline differentially methylated regions. Unlike in mice, H3K27me3-dependent imprinting is not observed in human early ***, allele-specific epigenomic reprogramming is different in humans and mice.

关键词： human embryo epigenetics reprogramming DNA methylation H3K27me3 chromatin accessibility