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Formation estimation and evolution mechanism of the pressure arch for non-circular tunnels under asymmetrical stress field

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Science China(Technological Sciences) 2024年第9期67卷 2919-2938页

作者： sun ZhenYu ZHANG DingLi XU tong chen Xu Key Laboratory for Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China

The tunneling-induced stress redistribution is dependent on the tunnel shape and the in-situ stress field, and the previous arch characterization method based on the circumferential or maximum principal stresses is only suitable for the circular tunnels under the hydrostatic stress field. In this study, a unified characterization method of the pressure arch for non-circular tunnels under the arbitrary stress field is proposed. By comparing the variations of compressive stress in different directions due to excavation, the ratio of the most significant increase in compressive stress is presented to characterize the arch effect, and the corresponding numerical algorithm is given. Since the proposed method takes the stress element as the basic analytical model, it can be easily applied to various complex excavation situations. Thereafter, combined with the established folding catastrophic model, an objective and unified quantitative method of the pressure arch boundaries is given. Using the proposed method, the longitudinal evolution of the pressure arch is analyzed. According to the expansion rate of the arch boundaries, three evolution stages including the initial formation, rapid expansion and stabilization are categorized. Parametric studies are conducted to illustrate the effect of ground properties and support stiffness on the pressure arch formation. It is found that the ground strength parameters and burial depth affect the arch range at a decreasing rate, while they have little effect on the arch shape. The lateral pressure coefficient has a significant effect on both the shape and range of the pressure arch. Increasing the support stiffness helps reduce the pressure arch range with a decreasing rate, while the synchronous variation of the elastic moduli of the surrounding rock and support does not affect the arch range under a certain relative elastic modulus. Finally, field monitoring is conducted to validate the proposed method in actual support design.

关键词： pressure arch stress redistribution numerical simulation quantitative characterization longitudinal evolution parametric study

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

Review on article of effects of tenofovir alafenamide and entecavir in chronic hepatitis B virus patients

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World Journal of Hepatology 2024年第1期16卷 109-111页

作者： Yu-tong sun Qian-Qian chen Department of Gastroenterology The First Medical Center of Chinese PLA General HospitalBeijing 100193China

This letter comments on the article which reported that tenofovir alafenamide may increase blood lipid levels compared with entecavir in patients with chronic hepatitis B published on World J Hepatol 2023 August *** review the related research content,topic selection,methodology,conclusions,strengths and weaknesses of this *** evaluate it in relation to other published relevant articles.

关键词： Tenofovir alafenamide Entecavir Serum lipid levels Hepatitis B virus

Forced boiling of nonazeotropic immiscible mixture in a supercapillary microchannel array for ultra-high heat flux removal with chip junction temperature below 85℃

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Science China(Technological Sciences) 2024年第5期67卷 1364-1380页

作者： sun Bo BAO Yuchen TIAN tong LI Ji School of Engineering Science University of Chinese Academy of SciencesBeijing100049China Laboratory of Advanced Thermal Management Technologies School of Engineering ScienceUniversity of Chinese Academy of SciencesBeijing100049China

In this study,a structure-optimized two-phase microchannel heat sink with sintered submicron nucleation sites was developed and *** copper-based microchannels had a rectangular cross-section with an equivalent hydraulic diameter of 222μ*** subcooled flow boiling characteristics were comprehensively compared between pure HFE-7100 and a non-azeotropic,immiscible binary mixture of HFE-7100 and water,considering heating areas of 1 and 5 cm^(2).The total heating power input to the test section were 100–1500 and 250–3000 W for a 1 and 5 cm^(2)heat source,respectively,with a flow rate ranging from 50 to150 L/*** to pure HFE-7100,the non-azeotropic immiscible binary mixture of HFE-7100/water in the sintered porous microchannels exhibited a much higher overall heat transfer coefficient and lower power *** maintain the junction temperature of a high power electronic chip below 85℃,the proposed supercapillary microchannel heat sink could effectively dissipate the heat flux of 1275 W/cm^(2)over 1 cm^(2)heat source and 500 W/cm^(2)over 5 cm^(2)heat *** addition,the volume ratio of the binary mixture strongly influence the two-phase flow heat transfer *** optimal volume ratio exist in terms of the thermal resistance–pumping power minimization(HFE-7100:water=2:8 is recommended in this study).The findings of this investigation on the flow boiling properties of non-azeotropic immiscible mixtures help fill a gap in the related field.

关键词： microchannel sintered powder coating submicron nucleation cavities nonazeotropic immiscible ultra-high heat flux

Persistent greening against drying in northeast Asian semiarid grasslands:Asymmetrical responses of direct and legacy effects to intensified drought

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Advances in Climate Change Research 2024年第1期15卷 9-20页

作者： Yu-tong MA Hai-Shan chen Yao-Ming SONG Bo-Tao ZHOU Shan-Lei sun Xin-Guan DU Yue sun Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China

Despite experiencing a decadal shift towards drought conditions at the end of the 2Oth century,semiarid grasslands in northeast Asia(NEA)exhibited an evident greening trend from 1982 to ***,the mechanism behind this phenomenon remains ***,we analysed the interdecadal changes in vegetation response to drought on the basis of the standardised precipitation evapotranspiration index(SPEI)and Global Inventory Modelling and Mapping Studies LAI4g datasets,with an emphasis on the differences between direct and legacy effects(as measured by resilience),to explore the mechanism of persistent grassland *** revealed that during the post-drought shift period(2000-2020),the sudden decrease in the water content of the intermediate soil layer triggered an intensified vegetation response to ***,although direct effects and resilience were amplified,they exhibited asymmetric *** was stronger than direct effects,and this difference increased with increasing drought(drought recovery)*** combined effects may account for persistent greening against intensified drying in the semiarid grasslands in *** the projected exacerbation of future droughts,this study holds notable importance for comprehending the long-term change dynamics of dryland ecosystems.

关键词： Semiarid grassland Drought decadal shift Direct effect Legacy effect(resilience) Northeast Asia

Learning the imaging mechanism directly from optical microscopy observations

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Photonics Research 2024年第1期12卷 7-26页

作者： ZE-HAO WANG LONG-KUN SHAN tong-TIAN WENG TIAN-LONG chen XIANG-DONG chen ZHANG-YANG WANG GUANG-CAN GUO FANG-WEN sun CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China University of Texas at Austin AustinTexas 78705USA Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

The optical microscopy image plays an important role in scientific research through the direct visualization of the nanoworld,where the imaging mechanism is described as the convolution of the point spread function(PSF)and *** on a priori knowledge of the PSF or equivalent PSF,it is possible to achieve more precise exploration of the ***,it is an outstanding challenge to directly extract the PSF from microscopy ***,with the help of self-supervised learning,we propose a physics-informed masked autoencoder(PiMAE)that enables a learnable estimation of the PSF and emitters directly from the raw microscopy *** demonstrate our method in synthetic data and real-world experiments with significant accuracy and noise *** outperforms DeepSTORM and the Richardson–Lucy algorithm in synthetic data tasks with an average improvement of 19.6%and 50.7%(35 tasks),respectively,as measured by the normalized root mean square error(NRMSE)*** is achieved without prior knowledge of the PSF,in contrast to the supervised approach used by DeepSTORM and the known PSF assumption in the Richardson–Lucy *** method,PiMAE,provides a feasible scheme for achieving the hidden imaging mechanism in optical microscopy and has the potential to learn hidden mechanisms in many more systems.

关键词： optical emitter mechanism

Electrochemical construction of 2,5-diaryloxazoles via N–H and C(sp_(3))-H functionalization

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Chinese Chemical Letters 2024年第4期35卷 340-345页

作者： tong Li Leping Pan Yan Zhang Jihu Su Kai Li Kuiliang Li Hu chen Qi sun Zhiyong Wang Hefei National Center for Physical Sciences at Microscale Key Laboratory of Precision and Intelligent ChemistrySchool of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefei 230026China Anhui University of Science and Technology Huainan 232001China CAS Key Laboratory of Microscale Magnetic Resonance Department of Modern PhysicsUniversity of Science and Technology of ChinaHefei 230026China

An efficient N–H and C(sp~3)-H functionalization of aryl ketones with benzylamines/amino acids was developed under mild conditions by virtue of anodic oxidation. A variety of functionalized 2,5-diaryloxazoles were obtained with good to excellent yields. Moreover, some important natural products can be prepared by this method. The reaction features a broad substrate scope, scalability, metal-free and chemical oxidant-free.

关键词： Electrochemical Metal-free Oxazole Oxidant-free

Boosting propane dehydrogenation of defective S-1 stabilized singleatom Pt and ZnO catalysts via coordination environment regulation

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Nano Research 2024年第7期17卷 5884-5896页

作者： Fuwen Yang Jie Zhang Jinwei chen Gang Wang tong Yu Qian Li Zongbo Shi Qiushi sun Runsheng Zhuo Ruilin Wang College of Materials Science and Engineering Sichuan UniversityChengdu 610065China Engineering Research Center of Alternative Energy Materials&Devices Ministry of EducationSichuan UniversityChengdu 610065China REZEL Catalysts Corporation Shanghai 200120China

Pt single atoms catalysts with precise coordination environment and high stability are expected to achieve high performance of propane dehydrogenation(PDH).In this work,an innovative synthetic strategy is proposed to construct the S-1@0.1Pt9Zn@DPS-1 nanocomposite as a highly efficient PDH *** engineering is applied to induce the formation of defective porous silicalite-1(DPS-1),which is favorable for achieving the uniformly distributed ZnO *** ZnO nanoclusters were further served as anchoring sites to stabilize the isolated Pt *** structural characterization revealed that penta-O coordinated Pt single atom coupled with ZnO nanoclusters decorated on the ***,the atomically dispersed Pt atoms with the ideal coordination environment could act as the predominant active sites for PDH *** expected,the optimal S-1@0.1Pt9Zn@DPS-1 catalyst delivered an excellent PDH performance(propane conversion of 40.7%,propylene selectivity of 97.5%)and good cycling regeneration *** work provides a new way for improving the activity and stability of catalysts in the field of industrial catalysts.

关键词： defect engineering single platinum atom coordination environment propane dehydrogenation propylene

Laser-assisted synthesis of PtPd alloy for efficient ethanol oxidation

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Nano Research 2024年第7期17卷 6032-6037页

作者： Zihang chen tong Liu Huijuan Zhang Beibei Pang Yuanhua sun Longfei Hu Qiquan Luo Xiaokang Liu Linlin Cao Tao Yao School of Nuclear Science and Technology National Synchrotron Radiation LaboratoryUniversity of Science and Technology of ChinaHefei 230029China Institutes of Physical Science and Information Technology Anhui UniversityHefei 230601China

The inefficiency of ethanol oxidation reaction(EOR)presents a significant obstacle in harnessing renewable biofuels with high energy density into *** efforts,most Pt-based catalysts still suffer from drawbacks such as poor activity and susceptibility to CO poisoning,particularly in acidic ***,we employed a physical laser-assisted approach to synthetize a PtPd alloy with a 1:1 atomic *** alloy demonstrates remarkable performance in acidic EOR,boasting a high mass activity of 1.86 A·mgPt^(−1)and competitive resistance to *** in situ synchrotron radiation infrared spectroscopy with theoretical calculations,we reveal that the synergic interaction between Pt and Pd enhances both the adsorption of OH*intermediate and the dehydrogenation ability of *** work will prove the feasibility of synthesizing bimetallic alloys by a physical laser-assisted strategy and promote the development of advanced alloy electrocatalysts.

关键词： laser-assisted strategy Pt-based alloy in situ synchrotron radiation infrared spectroscopy ethanol oxidation reaction synergic interaction