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Surrounding rock pressure in the tunnel portal section through moraine under freeze-thaw action

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Journal of Mountain Science 2024年第7期21卷 2480-2493页

作者： CHEN Zhimin liu Baoli liu Yaohui XU jiangtao school of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730070China CSCEC AECOM Consultants Co. ltdLanzhou 730000China National and Local Joint Engineering Laboratory of Road and Bridge Engineering Disaster Prevention Technology Lanzhou Jiaotong UniversityLanzhou 730070China

Moraines,characterized by the accumulation of rock and soil debris transported by glacial activity,present unique challenges for tunnel construction,particularly in portal sections,due to prevailing geographical and climatic conditions that facilitate freeze-thaw *** these challenges,there is a dearth of studies investigating the influence of freeze-thaw action and water content on the mechanical properties of moraines,and no research on calculating surrounding rock pressure in moraine tunnels subjected to freeze-thaw *** this study,direct shear tests under freeze-thaw cycles were conducted to examine the effects of freeze-thaw cycles and water content on the mechanical properties of frozen moraine.A comprehensive parameter K,integrating the number of freeze-thaws and water content,was introduced to model cohesion *** on Terzaghi Theory,we propose an improved algorithm for calculating surrounding rock pressure at the portal section of moraine *** a tunnel as a case study,surrounding rock pressure was calculated under various conditions to validate the Improved Algorithm's *** results show that:(1)Strength loss exhibits a linear trend with the number of freeze-thaw cycles at water content levels of 4%and 8%,while at 12%water content,previous freeze-thaw cycles induce more significant damage to the soil.(2)Moraine saturation peaks between 8%and 12%water *** repeated freeze-thaw cycles,moraine shear strength initially increases before decreasing with varying water content.(3.The internal friction angle of moraine experiences slight reductions with prolonged freeze-thaw cycles,but both freeze-thaw cycles and water content significantly influence cohesion.(4)Vertical surrounding rock pressure increases after the initial freeze-thaw cycle,particularly with higher water content,although freeze-thaw cycles have minimal effect on it.(5)Freeze-thaw cycles lead to a substantial increase in lateral surrounding rock pre

关键词： Moraines Freeze-thaw cycles Direct shear test Surrounding rock pressure

Multi-Objective Optimization Based on Life Cycle Assessment for Hybrid Solar and Biomass Combined Cooling,Heating and Power System

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Journal of Thermal Science 2024年第3期33卷 931-950页

作者： liu Jiejie LI Yao MENG Xianyang WU jiangtao Key Laboratory of Thermo-Fluid Science and Engineering Ministry of EducationXi’an Jiaotong UniversityXi’an710049China

The complementary of biomass and solar energy in combined cooling,heating and power(CCHP)system provides an efficient solution to address the energy crisis and environmental *** work aims to propose a multi-objective optimization model based on the life cycle assessment(LCA)method for the optimal design of hybrid solar and biomass *** life-cycle process of the poly-generation system is divided into six phases to analyze energy consumption and greenhouse gas *** comprehensive performances of the hybrid system are optimized by incorporating the evaluation criteria,including environmental impact in the whole life cycle,renewable energy contribution and economic *** non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ)with the technique for order preference by similarity to ideal solution(TOPSIS)method is employed to search the Pareto frontier result and thereby achieve optimal *** developed optimization methodology is used for a case study in an industrial *** results indicate that the best performance from the optimized hybrid system is reached with the environmental impact load reduction rate(EILRR)of 46.03.,renewable energy contribution proportion(RECP)of 92.73.and annual total cost saving rate(ATCSR)of3..75%,*** comparing pollutant-eq emissions of different stages,the operation phase emits the largest pollutant followed by the phase of raw material ***,this study reveals that the proposed multi-objective optimization model integrated with LCA method delivers an alternative path for the design and optimization of more sustainable CCHP system.

关键词： combined cooling heating and power system solar-biomass multi-objective optimization life cycle assessment optimal design

The resonance Rayleigh scattering of the interaction of copper(Ⅱ)-bleomycinA2 with DNA and its analytical application

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Science china chemistry 2010年第3期53卷 618-624页

作者： liu jiangtao1,liu shaopu2.& liu zhongfang2.1school of chemistry,chongqing Normal {3.,chongqing 4003.0,china 2school of chemistry and Chemical Engineering,Southwest {3.,chongqing 400715,china school of chemistry Chongqing Normal University Chongqing China school of chemistry and Chemical Engineering Southwest University Chongqing China

The forming of bleomycinA2-Cu(Ⅱ) cationic chelate and the interaction of the chelate with DNA have been investigated by using resonance Rayleigh scattering(RRS),molecular absorption and fluorescence *** result shows that in aqueous solution,bleomycinA2(BLMA2) can react with Cu(Ⅱ) to form 1:1 cationic chelate which contributes to the changes of the absorption spectra and the quenched fluorescence of *** the cationic chelate further bound with DNA to form ternary ion-association complexes,the remarkable enhancement of the RRS intensity was *** this work,the optimum conditions for the coordination reaction of BLMA2 with Cu(Ⅱ) and some influencing factors have been *** reaction mechanism of BLMA2-Cu(Ⅱ) binding with DNA was suggested and a binding model was *** addition,the fluorescence quenching type of BLMA2 was investigated.A highly sensitive,simple and rapid new method for the determination of DNA by using BLMA2-Cu(Ⅱ) as RRS probe has been *** detection limits(3.) are 7.2 ng/mL for ctDNA,7.1 ng/mL for sDNA and 18 ng/mL for *** method can be applied to the determination of trace amounts of DNA.

关键词： bleomycinA2 Cu(Ⅱ) DNA resonance Rayleigh scattering fluorescence quenching

Moirésuperlattice effects on interfacial mechanical behavior:A concise review

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Interdisciplinary Materials 2024年第3期3卷 343-357页

作者： Weidong Yan jiangtao liu Wengen Ouyang Ze liu Department of Engineering Mechanics School of Civil EngineeringWuhan UniversityWuhanChina school of Physics and Mechatronic Engineering Guizhou Minzu UniversityGuiyangChina State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhanChina The Institute of Technological Sciences Wuhan UniversityWuhanChina

The moirésuperlattice,arising from the interface of mismatched single crystals,intricately regulates the physical and mechanical properties of materials,giving rise to phenomena such as superconductivity and *** study delves into the profound impact of moirésuperlattices on the interfacial mechanical behavior of van der Waals(vdW)layered materials,with a particular focus on tribological properties.A comprehensive review of continuum modeling approaches for vdW layered materials is presented,accentuating the incorporation of moirésuperlattice effects in theoretical models to unravel their distinctive interfacial frictional behavior and thermodynamic *** exploration of moirésuperlattices has significantly advanced our fundamental understanding of interface phenomena in vdW layered *** progress provides crucial theoretical insights that can inform the design of multifunctional devices based on the unique properties of twisted layered materials.

关键词： interfacial mechanics moirésuperlattice superlubricity twist angle van der Waals layered materials

Resonance Rayleigh scattering study of the interaction of bleomycinA_5 with nucleic acids and its analytical application

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Science china chemistry 2007年第5期50卷 629-637页

作者： liu jiangtao1,2, liu {2.1 & liu shaopu1 1 school of chemistry and Chemical Engineering, Southwest university, chongqing 400715, china 2 Department of chemistry, Fuling Normal university, chongqing 408000, china school of chemistry and Chemical Engineering Southwest UniversityChongqing400715China Department of chemistry Fuling Normal UniversityChongqing 408000China

The interaction of bleomycinA5 with nucleic acids has been investigated byusing resonance Rayleigh scattering (RRS),molecular absorption and fluorescence *** resultshows that in near pH 2.2 buffer medium and absence of any metal ions,nucleic acids are capable ofbinding with bleomycinA5 (BLMA5) to form complexes which can remarkably enhance the RRS intensityand result in batho-chromic and hyperchromic molecular absorption of nucleic acids and fluorescencequenching of *** RRS spectral characteristics for the binding products of bleomycinA5with various DNA and RNA are similar,and the maximum RRS peaks are at 3.1 nm for ctDNA and sDNA,3.0nm for hsDNA,3.0 nm for RNAtypeVI and RNAtypelll,*** increments of RRS intensity aregreatly different in which DNA enhances greatly and RNA enhances *** this work,the optimumconditions of the interaction and some influencing factors have been *** reactionmechanism and a binding model for the interaction of BLMA5 with the nucleic acids are ***,a highly sensitive,simple and rapid new method for the determination of DNA has *** detection limits (3.sigma) are 5.7 ng/mL for ctDNA,7.4 ng/mL for sDNA and 9.2 ng/mLfor hsDNA,*** method can be applied to determination of trace amounts of DNA.

关键词： bleomycinA5, nucleic acids, resonance Rayleigh scattering, fluorescence quenching, absorption spectrum.

Mo_(2)P Monolayer as a Superior Electrocatalyst for Urea Synthesis from Nitrogen and Carbon Dioxide Fixation:A Computational Study

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Energy & Environmental Materials 2024年第1期7卷 207-214页

作者： Dongxu Jiao Zhongxu Wang Yuejie liu Qinghai Cai Jingxiang Zhao Carlos R.Cabrera zhongfang Chen College of chemistry and Chemical Engineering and Key Laboratory of Photonic and Electronic Bandgap Materials Ministry of EducationHarbin Normal UniversityHarbin 150025China Modern Experiment Center Harbin Normal UniversityHarbin 150025China Heilongjiang Province Collaborative Innovation Center of Cold Region Ecological Safety Harbin 150025China Department of chemistry and Biochemistry The University of Texas at El PasoEl Paso TX 79968USA Department of chemistry University of Puerto RicoRio Piedras CampusSan JuanPuerto Rico 00931USA

Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather ***,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea *** results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic ***,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.3. eV)for C-N coupling,low limiting potential(-0.3. V),and significant suppressing effects on the competing side *** outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active *** findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.

关键词： C-N coupling density functional theory Mo_(2)P monolayer urea synthesis

Climate and Soil Geochemistry Influence the Soil Organic Carbon Content in Drylands of the Songliao Plain, Northeast china

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Acta Geologica Sinica(English Edition) 2024年第5期98卷 1394-1403页

作者： liu Kai DAI Huimin SONG Yunhong LIANG Shuai YANG zhongfang school of Earth Sciences and Resources China University of Geosciences Key Laboratory of Black Soil Evolution and Ecological Effect Ministry of Natural Resources/Liaoning Province Shenyang Center of china Geological Survey Northeast Geological S&T Innovation Center of China Geological Survey

The understanding of the spatial distribution of soil organic carbon(SOC) and its influencing factors is crucial for comprehending the global carbon cycle. However, the impact of soil geochemical and climatic conditions on SOC remains limited, particularly in dryland farming areas. In this study, we aimed to enhance the understanding of the factors influencing the distribution of SOC in the drylands of the Songliao Plain, Northeast china. A dataset comprising 3.,188 measured soil samples was used to map the SOC distribution in the region. Multiple linear regression(MLR) and random forest models(RFM) were employed to assess the importance of driving indicators for SOC. We also carried out partial correlation and path analyses to further investigate the relationship between climate and geochemistry. The SOC content in dryland soils of the Songliao Plain ranged from 0.05% to 11.63., with a mean value of 1.47% ± 0.90%. There was a notable increasing trend in SOC content from the southwest to the northeast regions. The results of MLR and RFM revealed that temperature was the most critical factor, demonstrating a significant negative correlation with SOC content. Additionally, iron oxide was the most important soil geochemical indicator affecting SOC variability. Our research further suggested that climate may exert an indirect influence on SOC concentrations through its effect on geochemical properties of soil. These insights highlight the importance of considering both the direct and indirect impact of climate in predicting the SOC under future climate change.

关键词： climate change Northeast china soil geochemistry soil organic carbon

Aurora B facilitates cholangiocarcinoma progression by stabilizing c-Myc

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Animal Models and Experimental Medicine 2024年第05期 626-640页

作者： Ke liu Xuxuan Zhou Fei Huang Lihao liu Zijian Xu chongqing Gao Keke Zhang Jian Hong Nan Yao Guohua Cheng College of Pharmacy Jinan University Department of Pathophysiology School of Medicine Jinan University school of Medicine Jinan University

Background: Cholangiocarcinoma(CCA), a malignancy that arises from biliary epithelial cells, has a dismal prognosis, and few targeted therapies are available. Aurora B, a key mitotic regulator, has been reported to be involved in the progression of various tumors, yet its role in CCA is still ***: Human CCA tissues and murine spontaneous CCA models were used to assess Aurora B expression in CCA. A loss-of-function model was constructed in CCA cells to determine the role of Aurora B in CCA progression. Subcutaneous and liver orthotopic xenograft models were used to assess the therapeutic potential of Aurora B inhibitors in ***: In murine spontaneous CCA models, Aurora B was significantly upregulated. Elevated Aurora B expression was also observed in 62.3. of human specimens in our validation cohort(143.CCA specimens), and high Aurora B expression was positively correlated with pathological parameters of tumors and poor survival. Knockdown of Aurora B by siRNA and heteroduplex oligonucleotide(HDO)or an Aurora B kinase inhibitor(AZD1152) significantly suppressed CCA progression via G2/M arrest induction. An interaction between Aurora B and c-Myc was found in CCA cells. Targeting Aurora B significantly reduced this interaction and accelerated the proteasomal degradation of c-Myc, suggesting that Aurora B promoted the malignant properties of CCA by stabilizing c-Myc. Furthermore, sequential application of AZD1152 or Aurora B HDO drastically improved the efficacy of gemcitabine in ***: Aurora B plays an essential role in CCA progression by modulating c-Myc stability and represents a new target for treatment and chemosensitization in CCA.

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Frequency Regulation of VSC-MTDC System with Offshore Wind Farms

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 275-286页

作者： Haoyu liu Chongru liu North china Electric Power university Beijing 102206China

Frequency regulation of voltage source converter-based multi-terminal high-voltage direct current(VSC-MTDC)system with offshore wind farms enhances the frequency stability by compensating the power for a disturbed AC ***,it is difficult to reasonably allocate frequency-regulation resources due to a lack of coordination mechanisms between wind farms and the MTDC ***,it is difficult for the frequency control of the wind farms to manage changes in wind speed;and the risk of wind-turbine stalls is ***,based on the kinetic energy of wind turbines and the power margin of the converters,the frequency-regulation capability of wind turbines is evaluated,and a dynamic frequency-support scheme considering the real-time frequency-support capability of the wind turbines and system frequency evolution is proposed to improve the frequency-support performance.A power adaptation technique at variable wind speeds is developed;the active power in the frequency-support stage and restoration stage is switched according to the wind speed.A hierarchical zoning frequency-regulation scheme is designed to use the frequency-regulation resources of different links in the MTDC system with wind *** simulation results show that the novel frequency-regulation strategy maintains frequency stability with wind-speed changes and avoids multiple frequency dips.

关键词： Wind generation voltage source converter-based multi-terminal high-voltage direct current(VSC-MTDC) frequency regulation cooperative control adaptive control variable wind speed