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Chinese Chemical Letters 2017年第7期28卷 1380-1384页

作者： Tian-Xiao Chen Feng Ning Hai-Sheng Liu Ke-Feng Wu Wei Li chang-bei ma School of Chemistry and Biological Engineering Changsha University of Science and Technology State Key Laboratory of Medical Genetics & School of Life Sciences Central South University

In this assay, a label-free fluorescent sensing platform based on triple-helix molecular switch（THMS） and G-quadruplex was developed for the detection of tetracycline. We demonstrated this approach by using THMS, which consists of a central section with a shortened 8-mer aptamer sequence with high affinity to tetracycline and flanked by two arm segments. G-rich oligonucleotide can specifically bind to thioflavin T（Th T） as a signal transduction probe（STP）. In the absence of tetracycline, THMS remains stable, the fluorescence of background is low. By the addition of target tetracycline, the aptamer-target binding results in the formation of a structured aptamer-target complex, which disassembles the THMS and releases the STP. The free STP self-assembles into G-quadruplex and specifically binds to Th T which generates a obvious fluorescence enhancement. Using the triple-helix molecular switch, the developed aptamer-based fluorescent sensing platform showed a linear relationship with the concentration of tetracycline ranging from 0.2 to 20.0 nmol/L. The detection limit of tetracycline was determined to be970.0 pmol/L. The assay avoids complicated modifications or chemical labeling, making it simple and cost-effective. So, it is expected that this aptamer-based fluorescent assay could be extensively applied in the field of food safety inspection.

关键词： Tetracycline Aptamer Label-free Triple-helix molecular switch G-quadruplex Thioflavin T

A review on graphite surface modification methods towards low carbon-containing refractories

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Journal of Iron and Steel Research International 2024年第6期31卷 1291-1303页

作者： Ting-ting Zhang Jun Ding bei-yue ma Zheng-long Liu Chao Yu Cheng-ji Deng The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

The rapid development of iron and steel metallurgy technology has promoted the continuous innovation and iteration of carbon-containing refractories for clean steel *** meet the high-quality requirements for clean steel production and full exploit the performance advantages of carbon-containing refractories in dynamic smelting environment,it is necessary to explore the role of graphite and modified graphite in carbon-containing *** on this,graphite surface modification methods,including surfactants,surface oxidation,and surface coating,and their applications in carbon-containing refractories are *** advantages and disadvantages of each method are analyzed for practical ***,combined with the existing problems,the application prospect of improved graphite in carbon-containing refractories is discussed.

关键词： Graphite Carbon-containing refractory Clean steel Surface modification Service performance

Multifunctional Film Assembled from N‑Doped Carbon Nanofiber with Co–N_(4)–O Single Atoms for Highly Efficient Electromagnetic Energy Attenuation

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Nano-Micro Letters 2024年第11期16卷 359-376页

作者： Jia Xu bei Li Zheng ma Xiao Zhang Chunling Zhu Feng Yan Piaoping Yang Yujin Chen College of materials Science and Chemical Engineering Harbin Engineering UniversityHarbin 150001People’s Republic of China Key Laboratory of In‑Fiber Integrated Optics College of Physics and Optoelectronic EngineeringHarbin Engineering UniversityHarbin 150001People’s Republic of China

Single-atom materials have demonstrated attractive physicochemical ***,understanding the relationships between the coordination environment of single atoms and their properties at the atomic level remains a considerable ***,a facile waterassisted carbonization approach is developed to fabricate well-defined asymmetrically coordinated Co–N_(4)–O sites on biomass-derived carbon nanofiber(Co–N_(4)–O/NCF)for electromagnetic wave(EMW)*** such nanofiber,one atomically dispersed Co site is coordinated with four N atoms in the graphene basal plane and one oxygen atom in the axial ***-depth experimental and theoretical studies reveal that the axial Co–O coordination breaks the charge distribution symmetry in the planar porphyrin-like Co–N_(4) structure,leading to significantly enhanced dielectric polarization loss relevant to the planar Co–N_(4) ***,the film based on Co–N_(4)–O/NCF exhibits light weight,flexibility,excellent mechanical properties,great thermal insulating feature,and excellent EMW absorption with a reflection loss of−45.82 dB along with an effective absorption bandwidth of 4.8 *** findings of this work offer insight into the relationships between the single-atom coordination environment and the dielectric performance,and the proposed strategy can be extended toward the engineering of asymmetrically coordinated single atoms for various applications.

关键词： Co single atoms Asymmetric coordination structure Axial oxygen coordination Electromagnetic wave absorption Multifunctional film

Drilling-based measuring method for the c-φ parameter of rock and its field application

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International Journal of Mining Science and Technology 2024年第1期34卷 65-76页

作者： bei Jiang Fenglin ma Qi Wang Hongke Gao Dahu Zhai Yusong Deng Chuanjie Xu Liangdi Yao State Key Laboratory for Tunnel Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Research Center of Geotechnical and Structural Engineering Shandong UniversityJinan 250061China

The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters.

关键词： Digital drilling Rock crushing zone c-u parameter Measurement method Field application

Testing method of rock structural plane using digital drilling

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2563-2578页

作者： Qi Wang Yuncai Wang bei Jiang Hongke Gao Fenglin ma Dahu Zhai Songlin Cai State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing100083China

The rock mass consists of rock blocks and structural planes,which can reduce its integrity and ***,accurately obtaining the characteristics of the rock mass structural plane is a prerequisite for evaluating stability and designing supports in underground ***,there are no effective testing methods for the characteristic parameters of the rock mass structural plane in underground *** paper presents the digital drilling technology as a new testing method of rock mass structural *** rock specimens with cracks of varying widths and angles were used to simulate the rock mass structural planes,and the multifunctional rock mass digital drilling test system was employed to carry out the digital drilling *** analysis focuses on the variation laws of drilling parameters,such as drilling pressure and drilling torque,affected by the characteristics of prefabricated cracks,and clarifies the degradation mechanism of rock equivalent compressive ***,an identification model for the characteristic parameters of rock mass structural planes during drilling is *** test results indicate that the average difference of the characteristics of prefabricated cracks identified by the equivalent compressive strength is 2.45°and 0.82 mm,*** identification model while drilling is verified to be correct due to the high identification *** on this,a method for testing the characteristic parameters of the surrounding rock structural plane while drilling is *** research offers a theoretical and methodological foundation for precise in situ identification of structural planes of the surrounding rock in underground engineering.

关键词： Structural planes in the rock mass Digital drilling Drilling parameters Equivalent compressive strength Testing method

Incorporating metapath interaction on heterogeneous information network for social recommendation

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Frontiers of Computer Science 2024年第1期18卷 33-48页

作者： Yanbin JIANG Huifang ma Xiaohui ZHANG Zhixin LI Liang chang College of Computer Science and Engineering Northwest Normal UniversityLanzhou 730070China Guangxi Key Lab of Multi-source Information Mining and Security Guangxi Normal UniversityGuilin 541001China Guangxi Key Laboratory of Trusted Software Guilin University of Electronic TechnologyGuilin 541004China

Heterogeneous information network(HIN)has recently been widely adopted to describe complex graph structure in recommendation systems,proving its effectiveness in modeling complex graph *** existing HIN-based recommendation studies have achieved great success by performing message propagation between connected nodes on the defined metapaths,they have the following major *** works mainly convert heterogeneous graphs into homogeneous graphs via defining metapaths,which are not expressive enough to capture more complicated dependency relationships involved on the ***,the heterogeneous information is more likely to be provided by item attributes while social relations between users are not adequately *** tackle these limitations,we propose a novel social recommendation model MPISR,which models MetaPath Interaction for Social Recommendation on heterogeneous information ***,our model first learns the initial node representation through a pretraining module,and then identifies potential social friends and item relations based on their similarity to construct a unified *** then develop the two-way encoder module with similarity encoder and instance encoder to capture the similarity collaborative signals and relational dependency on different *** experiments on five real datasets demonstrate the effectiveness of our method.

关键词： heterogeneous information network social reco-mmender system metapath interaction attention mechanism

Anisotropic swelling pressures of compacted GMZ bentonite infiltrated with salt solutions

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3772-3785页

作者： Jing ma Yong-Gui Chen Ling-Yan Jia Wei-Min Ye Dong-bei Wu Qiong Wang Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China State Key Laboratory of Disaster Reduction in Civil Engineering College of Civil EngineeringTongji UniversityShanghai200092China School of Chemical Science and Engineering Tongji UniversityShanghai200092China

In the high-level radioactive waste(HLW)deep geological repository,bentonite is compacted uniaxially,and then arranged vertically in engineered *** assembly scheme induces the initial anisotropy,and with hydration,it develops more evidently under chemical *** investigate the anisotropic swelling of compacted Gaomiaozi(GMZ)bentonite and the further response to saline effects,a series of constant-volume swelling pressure tests were *** showed that dry density enhanced the bentonite swelling and raised the final anisotropy,whereas saline inhibited the bentonite swelling but still promoted the final *** final anisotropy coefficient(ratio of radial to axial pressure)obeyed the Boltzmann sigmoid attenuation function,decreasing with concentration and dry density,converging to a minimum value of *** staged evolution of anisotropy coefficient was discovered,that saline inhibited the rise of the anisotropy coefficient(Dd)in the isotropic process greater than the valley(d1)in the anisotropic process,leading to the final anisotropy *** isotropic stage amplified the impact of soil structure rearrangement on the macro-swelling pressure ***,a new method for predicting swelling pressures of compacted bentonite was proposed,by expanding the equations of Gouy-Chapman theory with a dissipative wedge *** evolutionary function was constructed,revealing the correlation between the occurrence time and the pressure value due to the structure rearrangement and the former crystalline ***,a design reference for dry density was given,based on the chemical conditions around the pre-site in beishan,*** anisotropy promoted by saline would cause a greater drop of radial pressure,making the previous threshold on axial swelling fail.

关键词： HLW deep geological repository Compacted GMZ bentonite Anisotropic swelling pressure Multi-scale structure Saline effect

Near-infrared non-fused electron acceptors for efficient organic photovoltaics

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Chinese Chemical Letters 2024年第4期35卷 436-441页

作者： Wenxiang ma Xinyu He Tianyi Chen De-Li ma Hongzheng Chen chang-Zhi Li State Key Laboratory of Silicon and Advanced Semiconductor materials Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NFRAs), PTBFTT-F and PTBFTT-Cl have been developed with A-π_A-π_D-D-π_D-π_A-A non-fused structures. It is revealed that the introduction of electron deficient π-bridge(π_A) and multiple intramolecular noncovalent interactions effectively retained the structural planarity and intramolecular charge transfer of NFRAs, extending strong NIR photon absorption up to 950 nm. Further, the chlorinated acceptor, with the enlarged π-surface compared to the fluorinated counterpart, promoted not only molecular stacking in solid, but also the desirable photochemical stability in ambient, which are helpful to thereby improve the exciton and charge dynamics for the corresponding OPVs. Overall, this work provides valuable insights into the design of NIR organic semiconductors.

关键词： Organic photovoltaic Near-infrared Non-fused electron acceptor Noncovalent interaction Stability

Spatial Equity Evaluation of Rural Eldercare Service Resources Based on Accessibility: A Case Study of Huanxian County of Gansu Province, China

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Chinese Geographical Science 2024年第5期34卷 869-885页

作者： chang Xiaoyan ma Libang CUI Xijuan TAO Tianmin ZHAO Shoucun College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730000China Key Laboratory of Resource Environment and Sustainable Development of Oasis Gansu ProvinceLanzhou 730070China Northwest Institute of Urban-Rural Development and Collaborative Governance Lanzhou 730070China

Safeguarding the elderly population in the countryside is an inherent requirement for alleviating social conflicts in rural areas and effectively carrying out China’s Rural *** existing spatial mismatch between rural elderly service facilities and pop-ulation distribution in China aggravates the imbalance of facility resource space,how to improve the accuracy of demand and supply results and better measuring the spatial fairness of elderly service is significant to realize the optimal allocation of rural elderly *** on the above,this study pays attention to the refined needs of the elderly population,and focuses on the spatial equity of the rural elderly facilities,to make up for the short boards of the basic public services in the countryside and realize the all-round rural *** study takes Huanxian County in the hilly loess area of Longdong,China as an example and explores the spatial equity of rural elderly services by using the Urban Spatial Network Analysis(UNA)to measure the accessible quantity and supply capacity of elderly *** results found that there were 553 rural eldercare service facilities in Huanxian County,including 285 eldercare facilities and 268 medical and health facilities,and the spatial distribution is characterized by a southward shift in the east and uneven regional ***,the supply capacity of rural pension services was generally good,with the township center as the gathering point and spreading out in a faceted manner,with nearby townships forming a contiguous area;however,there were strong contrasts and obvious differences in the strength of supply ***,the spatial equity of rural eldercare service was *** 42.05%of the eld-erly population grid cells,eldercare service spatial equity was extremely *** spatial distribution also presented a northern preference over the southern,a western preference over the eastern,and a concentration along the *** stud

关键词： rural eldercare service spatial equity hilly loess region of Longdong Huanxian County China

Stage separation of recoverable liquid launch vehicle by using moving pulsating ball analogue for propellant sloshing

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Chinese Journal of Aeronautics 2024年第2期37卷 360-370页

作者： Yu LU Baozeng YUE Bailong HAO Bole ma Feng LIU Yuanyuan chang School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China beijing Institute of Astronautical Systems Engineering Beijing 100076China

In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be *** calculation simplicity and operation practicability,the Moving Pulsating Ball Model(MPBM)of large amplitude liquid sloshing is introduced into the calculation of launch vehicle stage *** the dynamic equation of the model with the energy relationship during"breathing movement",the formula calculating the force of liquid on the rigid body is *** with the calculations of commercial CFD calculation software,the accuracy of MPBM model is ***,all the external forces and moments are applied to the rigid body of the stages,so that the translational and rotational dynamic equations of the stages are obtained *** to the relative position of the two stages,the geometric shape of the interstage section and the engine of the second stage,the minimum clearance in the separation process can be decided to guarantee that the separation process is safe.

关键词： Moving Pulsating Ball Model(MPBM) Dynamics of stage separation Large amplitude sloshing Recoverable liquid launch vehicle Flight dynamics