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Modified Sadowski formula-based model for the slope shape amplification effect under multistage slope blasting vibration

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International Journal of Mining Science and Technology 2024年第5期34卷 631-641页

作者： Xiaogang Wu Mingyang Wang hao lu Yongjun Zhang Wen nie State Key laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China State Key laboratory of Metal Mine Safety and health Ma’anshan 243000China School of Civil Engineering Qingdao University of TechnologyQingdao 266520China

Blasting operations,which are crucial to open-pit mine production due to their simplicity and efficiency,require precise control through accurate vibration velocity *** conventional Sadowski formula mainly focuses on blast center distance but neglects the amplification effect of blasting vibration waves by terraced terrain,from which the calculated blasting vibration velocities are smaller than the actual values,affecting the safety of the *** address this issue,our model introduces the influences of slope and time into Sadowski formula to measure safety through blast vibration *** the northern section of the open-pit quartz mine in Jinchang City,Gansu Province,China,the data of a continuous blasting slope project are referred *** findings reveal a noticeable vibration amplification effect during blasting when a multi-stage slope platform undergoes a sudden cross-sectional change near the upper overhanging *** amplification vibration coefficient increases with height,while vibration waves within rocks decrease from bottom to ***,platforms without distinct crosssectional changes exhibit no pronounced amplification during *** addition,the vibration intensity decreases with distance as the rock height difference change *** results obtained by the proposed blast vibration displacement equation incorporating slope shape influence closely agree with real-world *** to Pearson correlation coefficient(PPMCC)analysis,the average accuracy rate of our model is 88.84%,which exceeds the conventional Sadowski formula(46.92%).

关键词： Multistage slope Slope shape influence factor Continuous blasting Sadowski formula Amplification effect

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Effect of Interface Form on Creep Failure and life of Dissimilar Metal Welds Involving Nickel-Based Weld Metal and Ferritic Base Metal

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 265-285页

作者： Xiaogang li Junfeng nie Xin Wang Kejian li haiquan Zhang Institute of Nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

For dissimilar metal welds(DMWs)involving nickel-based weld metal(WM)and ferritic heat resistant steel base metal(BM)in power plants,there must be an interface between WM and BM,and this interface suffers mechanical and microstructure mismatches and is often the rupture location of premature *** this study,a new form of WM/BM interface form,namely double Y-type interface was designed for the *** behaviors and life of DMWs containing double Y-type interface and conventional I-type interface were compared by finite element analysis and creep tests,and creep failure mechanisms were investigated by stress-strain analysis and microstructure *** applying double Y-type interface instead of conventional I-type interface,failure location of DMW could be shifted from the WM/ferritic heat-affected zone(hAZ)interface into the ferritic hAZ or even the ferritic BM,and the failure mode change improved the creep life of *** interface premature failure of I-type interface DMW was related to the coupling effect of microstructure degradation,stress and strain concentrations,and oxide notch on the WM/hAZ *** creep failure of double Y-type interface DMW was the result of Type IV fracture due to the creep voids and micro-cracks on fine-grain boundaries in hAZ,which was a result of the matrix softening of hAZ and lack of precipitate pinning at fine-grain *** double Y-type interface form separated the stress and strain concentrations in DMW from the WM/hAZ interface,preventing the trigger effect of oxide notch on interface failure and inhibiting the interfacial microstructure *** is a novel scheme to prolong creep life and enhance reliability of DMW,by means of optimizing the interface form,decoupling the damage factors from WM/hAZ interface,and then changing the failure mechanism and shifting the failure location.

关键词： Dissimilar metal weld Nickel-based weld metal Ferritic heat resistant steel Interface Creep strain Microstructure Failure mechanism Creep life

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Ameliorating the Strength-Modulus Synergy in GNPs Reinforced Mg-Zn-Zr Composites via Multidirectional Forging and hot Extrusion Deformation

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Acta Metallurgica Sinica(English letters) 2024年第3期37卷 425-437页

作者： Yuhao Chen Kaibo nie Kunkun Deng Zhilong liu Quanxin Shi College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key laboratory of Compressor Technology(Compressor Technology laboratory of Anhui Province) Hefei 230031China Instrumental Analysis Center Taiyuan University of TechnologyTaiyuan 030024China

The integration of lightweight and high-modulus magnesium-based materials is becoming increasingly valued as structural materials due to the complexity and intelligence of industrial products like automobiles and *** this study,the graphene nanoplatelets(GNPs)/Mg-Zn-Zr composites with 0.5 wt%GNPs were successfully prepared by the combination of multidirectional forging(MDF)and hot extrusion(Ex).The newly-developed composites after multi-step deformation possessed excellent strength and modulus,with a tensile strength exceeding 375 MPa and an elastic modulus reaching 54 *** results revealed that the stripping and thinning of GNPs bands parallel to the extrusion direction occurred after MDF+Ex,which promoted the dynamic recrystallization and the formation of numerous fine *** significant improvement in comprehensive mechanical performances of the composites could be primarily ascribed to the refinement of grain size caused by the optimized distribution of GNPs,and efficient load transfer facilitated by the tight interface.

关键词： Magnesium matrix composites Graphene nanoplatelets(GNPs) Multi-step deformation Microstructure Strength-modulus

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Monitoring of Cell Membrane Microenvironment Based on DNA Nanodevices

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Chemical Research in Chinese Universities 2024年第2期40卷 255-267页

作者： NAN hexin CAI Ming KUANG Shi nie Zhou State Key laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan Provincial Key Laboratory of Biomacromolecular Chemical BiologyHunan UniversityChangsha410082P.R.China

The cell membrane is a critical barrier for cellular homeostasis,integral to signaling and intercellular communication,and vital for understanding cellular functions and disease *** its microenvironment is crucial for uncovering the molecular basis of physiological and pathological processes associated with the cell membrane,driving the development of bioanalytical toolkits capable of dynamically monitoring the cell surface *** the continuous advancement of functional nucleic acids and dynamic DNA nanotechnology,DNA nanodevices with controllable nanosized geometry,specific molecular recognition,and selective membrane-localization properties offer a versatile platform for probing the cell membrane *** this review,we summarize the current biosensing and membrane-anchoring mechanisms of DNA nanodevices and highlight their use in studying key cell membrane events,including membrane lipid dynamics,transmembrane transport,receptor dimerization,and signal ***,we discuss the challenges and potential future applications of DNA nanodevices in advancing cell membrane biology research and biomedical applications.

关键词： DNA nanodevice Cell membrane Cellular micro-environment Monitoring

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Convergence analysis for complementary-label learning with kernel ridge regression

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Applied Mathematics(A Journal of Chinese Universities) 2024年第3期39卷 533-544页

作者： nie Wei-lin WANG Cheng XIE Zhong-hua School of Mathematics and Statistics Huizhou UniversityHuizhou 516007China School of Computer Science and Engineering Huizhou UniversityHuizhou 516007China

Complementary-label learning(Cll)aims at finding a classifier via samples with complementary *** data is considered to contain less information than ordinary-label *** transition matrix between the true label and the complementary label,and some loss functions have been developed to handle this *** this paper,we show that Cll can be transformed into ordinary classification under some mild conditions,which indicates that the complementary labels can supply enough information in most *** an example,an extensive misclassification error analysis was performed for the Kernel Ridge Regression(KRR)method applied to multiple complementary-label learning(MCll),which demonstrates its superior performance compared to existing approaches.

关键词： multiple complementary-label learning partial label learning error analysis reproducing kernel hilbert spaces

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Exact satisfiability and phase transition analysis of the regular(k,d)-CNF formula

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Frontiers of Computer Science 2024年第1期18卷 263-265页

作者： Guoxia nie Daoyun XU Xi WANG Zaijun ZhANG College of Computer Science and Technology Guizhou UniversityGuiyang 550025China School of Mathematics and Statistics Qiannan Normal University for NationalitiesDuyun 558000China Key laboratory of Industrial Automation and Machine Vision of Qiannan Duyun 558000China

1Introduction The satisfiability(SAT)problem has been considered the"seed"of other NP-complete *** regular partial exact(k,d)-SAT problem is an important extension of the SAT *** any(k,d)-CNF formula with a variable set V,V'is a proper subset of V,the problem involves determining whether a truth assignment set on V'exists such that only a literal in each clause is *** V'=V,it is a regular exact(k,d)-SAT ***,both experimental verifications and theoretical analyses of k-SAT problem have shown that the ratioα(clause constraint density)of the number of clauses m to the number of variables n is an important parameter affecting the satisfiability of the formula[1].however,the regular(k,d)-SAT problem has the same clause constraint density d/k.

关键词： formula constraint exact

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Enzyme-driven Nanorobots Walking Along Predesigned Tracks on the DNA Origami for Cargo Transport and Catalysis

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Chemical Research in Chinese Universities 2024年第2期40卷 333-342页

作者： nie Cunpeng MA Tianran ChEN Tingting ChU Xia State Key laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha410082P.R.China

In molecular engineering,designing and synthesizing molecular machines with capable of performing complex tasks,remains a formidable *** is an excellent candidate for building molecular robots because it is highly ***,we present an artificial nanorobot,in which a DNA cube serves as the inert‘body’,and nucleic acid catalysts based on an enzymatic nicking reaction act as the‘legs’for *** nanorobot can execute a series of actions,such as‘start’,‘turn’,and‘stop’when it walks along a predefined *** performance could be confirmed and monitored by using an atomic force microscope(AFM)and fluorescence *** by biological machines,we artificially designed a series of specialized tasks that combined walking with control of cargo transport and ***-time fluorescence kinetics curves provide monitoring signals for cargo transport and catalytic *** work can enrich the toolbox of DNA machinery and has great potential for engineering molecular nanofactories.

关键词： DNA origami DNA nanorobot Controlled cargo transport DNAzyme catalysis

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Resilience effects for household food expenditure and dietary diversity in rural western China

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Journal of Integrative Agriculture 2024年第2期23卷 384-396页

作者： Xiao han Kaiyu lyu Fengying nie Yuquan Chen Institute of Agricultural Economics and Development Chinese Academy of Agricultural SciencesBeijing 100081China Agricultural Information Institute Chinese Academy of Agricultural SciencesBeijing 100081China Academy of Global Food Economics and Policy China Agricultural UniversityBeijing 100083China

A more resilient livelihood is increasingly recognized as an efficient way to improve vulnerable households’food security and optimize their dietary *** study quantifies rural household resilience in western China,identifies the three pillars(absorptive capacity,adaptive capacity,and transformative capacity)contribution to resilience,and then establishes the estimated Resilience Capacity Index(RCI)linked with food security and dietary diversity supported by the multiple indicator multiple cause(MIMIC)*** show that,despite geographical heterogeneity,the RCI consistently increased from 2015 to *** with a higher RCI inheriting better capacity to deal with risk and shocks are significantly and positively correlated with increasing food expenditure and diversifying food *** can be because resilient households will allocate more money to food expenditure instead of saving for livelihood ***,policymakers can provide more incentives for rural households to adopt more dynamic and effective risk management ***,in turn,could yield positive spillover effects by preventing human capital loss associated with dietary-related chronic diseases and mortality.

关键词： resilience food expenditure dietary diversity China risk management

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Conductive edge-warping graphite mesas for robust structural superlubricity

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Science China(Technological Sciences) 2024年第7期67卷 2040-2049页

作者： FENG WeiJia lIU Ying MA Ming PENG Deli nie Jinhui State Key laboratory of Tribology in Advanced Equipment&Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Center for Nano and Micro Mechanics Tsinghua UniversityBeijing 100084China Institute of Superlubricity Technology Research Institute of Tsinghua University in ShenzhenShenzhen 518057China

Structural superlubricity(SSl) refers to a state of ultralow friction and zero wear when two solid surfaces slide against each other. Recent investigations have identified amorphous carbon at the edge of the graphite mesa as the primary source of friction in such SSl systems. here, the tensile stress of metal thin film is exploited to engineer vertically conductive edge-warping graphite mesas(EWGM). Through this approach, robust SSl performance is realized, demonstrated by sliding an 8 μm side length square EWGM on an atomically smooth Au substrate for 10000 cycles at a constant voltage of 1 m V. In this SSl system,differential friction coefficients lower than 1.5 × 10^(-4) are achieved, with static contact resistance between EWGM and Au substrate as low as 28Ω and sliding contact resistance as low as 32Ω. Moreover, the EWGM exhibits SSl behavior on polished Si wafer substrates. Furthermore, because of the no-edge contact with the substrate during sliding, friction is independent of the sliding speed of the EWGM. This study presents the first successful fabrication of conductive EWGM. Remarkably, in both EWGM-Au and EWGM-Si SSl systems, the measured frictions are more than one order of magnitude lower than those of ordinary self-retracting graphite mesas with no-edge warping, and no wear is observed during extended current-carrying ***, these findings establish a solid groundwork for the future realization of macroscale conductive SSl systems.

关键词： structural superlubricity graphite mesa contact resistance tensile stress edge warping

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Selective immobilization of Pb(Ⅱ)by biogenic whewellite and its mechanism

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Journal of Environmental Sciences 2024年第3期137卷 664-676页

作者： Xingxing Wang Kaiyan Ren Kairui Jiao Wenjun nie Xiaochi An Bin lian College of life Sciences College of Marine Science and EngineeringNanjing Normal UniversityNanjing 210023China

The development of bio-adsorbents with highly selective immobilization properties for specific heavy metals is a great challenge,but has important application *** whewellite(BW)with high selectivity for Pb(Ⅱ)was synthesized by mineral microbial *** selective immobilization properties and mechanism of BW for Pb(Ⅱ)were analyzed by combining mineral characterization technology and batch adsorption research *** results indicated that BW can efficiently and selectively immobilize Pb(Ⅱ)in single or composite heavy metal adsorption solutions,and the immobilized Pb(Ⅱ)is difficult to *** undergoes monolayer adsorption on Pb(Ⅱ),Qmax≈1073.17 mg/*** immobilization of Pb(Ⅱ)by BW is a physico-chemical adsorption process with spontaneous heat absorption and an accompanying increase in *** addition,the sequestration of Pb(Ⅱ)by BW remains around 756.99 mg/g even at p h=*** excellent selective immobilization properties of BW for Pb(Ⅱ)are closely related to its smaller Ksp,electrostatic repulsion effect,organic-inorganic composite structure,acid resistance and the formation of Pb(Ⅱ)*** study provides beneficial information about the recycling of lead in acidic lead-containing wastewater and composite heavy metal contaminated water bodies.

关键词： Aspergillus niger Biogenic whewellite Pb(Ⅱ) Selective adsorption Immobilization mechanism

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