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Role of Surface Hydrogen Bonds in Determining the Friction Behaviors of Hydrogenated Diamond-like Carbon Films

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Chinese Physics Letters 2012年第5期29卷 189-192页

作者： WANG Cheng-Bing SHI Jing GENG Zhong-Rong ZHANG Jun-Yan National Engineering Research center for Technology and Equipment of Green Coating Lanzhou Jiaotong UniversityLanzhou 730070 State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000

Friction behaviors of hydrogenated diamond-like carbon (H-DLC) films are investigated on a ball-on-disk type tribometer in dry N2 and dry *** result shows that the friction behaviors of the H-DLC films are very sensitive to the testing environment,the H-DLC films exhibit a very low friction coefficient of 0.016 in dry N2,and similarly in an inert gas the friction coefficient increases to about 0.063 in dry *** the testing conditions,friction results,SEM and XPS investigation,it is concluded that the friction behaviors of the hydrogenated DLC films are associated with surface hydrogen of the H-DLC films and are dictated by whether or not hydrogen bonds are formed between the transfer films/H-DLC films at the sliding interface.A hydrogen-induced hydrogen bond model is proposed to interpret the friction behaviors of hydrogenated DLC films in different environments.

关键词： friction hydrogen vacuum

Rescattering mechanism of weak decays of double-charm baryons

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Chinese Physics C 2021年第5期45卷 77-99页

作者： Jia-Jie Han Hua-Yu Jiang Wei Liu Zhen-Jun Xiao Fu-Sheng Yu School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China Theoretische Physik 1 Naturwissenschaftlich-Technische FakultatUniversitat Siegen57068 SiegenGermany lanzhou center for Theoretical Physics Lanzhou UniversityLanzhou 730000China Frontier Science center for Rare Isotopes Lanzhou UniversityLanzhou 730000China center for High Energy Physics Peking UniversityBeijing 100871China

The doubly charmed baryon■cc++was recently observed by LHCb via the decay processes of■cc++→∧+cK^(-)π^(+)π^(+)and■c+π^(+).These discovery channels were successfully predicted in a framework in which the short-distance contributions are calculated under the factorization hypothesis and the long-distance contributions are estimated using the rescattering mechanism for the final-state-interaction *** this paper,we illustrate the above framework in detail by systematic studies on the tw o-body baryonic decays Bcc→BcP involving the doubly charmed baryons Bcc=(■cc++,■cc++,Ωcc+),the singly charmed baryons Bc=(B3,B6)and the light pseudoscalar mesons P=(π,K,η1,8).

关键词： double-charm baryon rescattering mechanism final-state interaction

Observing dynamic oscillatory behavior of triple points among black hole thermodynamic phase transitions

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Science China(Physics,Mechanics & Astronomy) 2021年第7期64卷 66-71页

作者： Shao-Wen Wei Yong-Qiang Wang Yu-Xiao Liu Robert B.Mann lanzhou center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu ProvinceSchool of Physical Science and TechnologyLanzhou UniversityLanzhou730000China Institute of Theoretical Physics&Research center of Gravitation Lanzhou UniversityLanzhou730000China Department of Physics and Astronomy University of WaterlooWaterlooN2L 3G1Canada

Understanding the dynamic process of black hole thermodynamic phase transitions at a triple point is a huge challenge. In this paper, we conduct the first investigation of dynamic phase behavior at a black hole triple point. By numerically solving the Smoluchowski equation near the triple point for a six-dimensional charged Gauss-Bonnet anti-de Sitter black hole, we report that initial small, intermediate, or large black holes can transit to the other two coexistent phases at the triple point, indicating that thermodynamic phase transitions can indeed occur dynamically. More significantly, we observe characteristic weak and strong oscillatory behavior in this dynamic process, which can be understood from an investigation of the rate of first passage from one phase to another. Our results further an understanding of the dynamic process of black hole thermodynamic phase transitions.

关键词： classical black hole thermodynamics phase transition Smoluchowski equation first passage time

ANALYSIS OF URBAN COMMERCIAL CENTRE’S LOCATION PATTERN AND ADVANTAGE DEGREE--TAKING lanzhou CITY AS AN EXAMPLE

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Journal of Geographical Sciences 1991年第3期 26-35页

作者： An Chengmu Ma Kun lanzhou Commercial College lanzhou University

According to the location theory,this paper researches the commercial centre’s grading principle,function model and location ***,the present structure and development trend of commercial centre in lanzhou are analysed and a sketch map on location pattern is drawn which is basically in conformity with that of ***’s traffic *** concept of location advantage degree of city’s commercial centres is proposed and defined as the quantitative description which shows the advantage degree of that commercial centre engaging in business *** mathematical models for calculating them are *** on the result,a corresponding analysis has been ***,the above mentioned qualitative and quantitative results are synthesized,some suggestions on rationally disposing the commercial centres and improving city’s commerce in lanzhou are given.

关键词： urban commercial centre location pattern market network location advantage degree

Distributed model predictive control based on adaptive sampling mechanism

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Chinese Journal of Chemical Engineering 2021年第11期34卷 193-204页

作者： Zhen Wang Aimin An Qianrong Li College of Electrical and Information Engineering Lanzhou University of TechnologyLanzhou 730050China Key Laboratory of Gansu Advanced Control for Industrial Processes Lanzhou 730050China National Experimental Teaching center of Electrical and Control Engineering Lanzhou 730050China

In this work,an adaptive sampling control strategy for distributed predictive control is *** to the proposed method,the sampling rate of each subsystem of the accused object is determined based on the periodic detection of its dynamic behavior and calculations made using a correlation ***,the optimal sampling interval within the period is obtained and sent to the corresponding sub-prediction controller,and the sampling interval of the controller is changed accordingly before the next sampling period *** the next control period,the adaptive sampling mechanism recalculates the sampling rate of each subsystem’s measurable output variable according to both the abovementioned method and the change in the dynamic behavior of the entire system,and this process is *** an adaptive sampling interval selection based on an autocorrelation function that measures dynamic behavior can dynamically optimize the selection of sampling rate according to the real-time change in the dynamic behavior of the controlled *** can also accurately capture dynamic changes,meaning that each sub-prediction controller can more accurately calculate the optimal control quantity at the next moment,significantly improving the performance of distributed model predictive control(DMPC).A comparison demonstrates that the proposed adaptive sampling DMPC algorithm has better tracking performance than the traditional DMPC algorithm.

关键词： Chemical process Distributed model predictive control Adaptive sampling mechanism Optimal sampling interval System dynamic behavior

Improved empirical formula for α particle preformation factor

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Chinese Physics C 2021年第1期45卷 302-314页

作者： Yan He Xuan Yu Hong-Fei Zhang School of Nuclear Science and Technology Lanzhou University730000 LanzhouChina Joint Department for Nuclear Physics Institute of Modem PhysicsCAS and Lanzhou University730000 LanzhouChina Engineering Research center for Neutron Application Ministry of EducationLanzhou University730000 LanzhouChina

In this contribution,the α preformation factors of 606 nuclei are extracted within the framework of the generalized liquid drop model(GLDM).Through the systematic analysis of the α preformation factors of even-even Po-U isotopes,we found that there is a significant weakening of influence of N=126 shell closure in uranium,which is consistent with the results of a recent experiment [*** et al.,***.115,242502(2015)],implying that N=126 may not be the magic number for U ***,we propose an improved formula with only 7 parameters to calculate α preformation factors suitable for all types of α-decay;it has fewer parameters than the original formula proposed by Zhang et al.[*** et al.,***.C 80,057301(2009)]with higher *** standard deviation of the α preformation factors calculated by our formula with extracted values for all 606 nuclei is 0.365 with a factor of 2.3,indicating that our improved formula can accurately reproduce the α preformation *** by this,the α-decay half-lives of actinide elements are predicted,which could be useful in future ***,the predicted α-decay half-lives of two new isotopes 220 Np [***,et al.,***.122,192503(2019)] and 219 Np [*** et al.,***.B 777,212(2018)] are in good agreement with the experimental α-decay half-lives.

关键词： a decay preformation factor generalized liquid drop model

A simple method to extract glacier length based on Digital Elevation Model and glacier boundaries for simple basin type glacier

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Journal of Mountain Science 2017年第9期14卷 1776-1790页

作者： JI Qin YANG Tai-bao HE Yi QIN Yan DONG Jun HU Fan-sheng Institute of Glaciology and Ecogeography College of Earth and Environmental Sciences Lanzhou University Lanzhou 73000 China Faculty of Geomatics Lanzhou Jiaotong University Lanzhou 730000 China Research center for Arid Area and Desert College of Earth and Environmental Sciences Lanzhou University Lanzhou 730000 China

Glacier length is a key morphological element that has many glaciological applications; however, it is often difficult to determine, especially for glaciers that cover larger spatial areas or those that exhibit frequent temporal change. In this paper, we describe a new Arc GIS-based method that can derive glacier flow lines for determining glacier length based on digital elevation model and glacier outlines. This method involves(1) extraction of the highest and lowest points on a glacier,(2) calculation of 10-m contour lines on the glacier from 10 m to 100 m height, and(3) connection of the midpoints of each contour line with the highest and the lowest points in order to create a flow line, which is subsequently smoothed. In order to assess the reliability of this method, we tested the algorithm's results against flow lines calculated using field measurements, analysing data from the Chinese Glacier Inventory, and manual interpretation. These data showed that the new automated method is effective in deriving glacier flow lines when contour lines are relatively large; in particular, when they are between 70 m and 100 m. Nonetheless, a key limitation of the algorithm is the requirement to automatically delete repeated and closed curves in the pre-treatment processes. In addition to calculating glacier flow lines for derivation of glacier length, this method also can be used to effectively determine glacier terminus change.

关键词： Glacier length Flow lines Glacier boundary DEM Arc GIS

Wireless remote spatiotemporal monitoring of high-fill foundation deformation

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Journal of Mountain Science 2023年第6期20卷 1620-1638页

作者： YANG Xiao-hui LI Zhi-qian ZHU Yan-peng GUO Nan School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Western Engineering Research center of Disaster Mitigation in Civil Engineering of Ministry of Education Lanzhou University of TechnologyLanzhou 730050China

The spatial and temporal deformation patterns and deformation control indicators of highfill foundations directly affect the design,construction and operational safety of high-fill *** situ monitoring can comprehensively reflect the deformation of high-fill during and after *** this paper,we have first designed and installed an integrated wireless remote monitoring system for high-fill to achieve real-time dynamic monitoring of settlement,pore water pressure and soil pressure of the fill *** on the monitoring results of nearly one year of the construction period and two years after construction,it was found that the deformation amount and deformation rate of the high-fill foundation showed a non-linear growth relationship with the filling rate and filling *** settlement deformation of the high-fill foundation during the loading period was mainly dominated by the original foundation soil,accounting for 54.4%of the total settlement on average;the settlement deformation during the post-construction period was mainly dominated by the filling body,accounting for 77.04%of the total settlement on average,and the settlement deformation during the post-construction period mainly occurred in the first year after *** analysis of the deformation mechanism suggests that the deformation of the filling body is dominated by exhaust consolidation during the loading period and drainage consolidation during the post-construction period;the deformation of the original foundation soil is dominated by drainage consolidation during the loading period and drainage consolidation develops slowly during the post-construction *** is recommended that the original foundation should be reinforced before the large area filling construction,and that the filling rate should be strictly controlled during *** research results can provide a scientific basis for deformation calculation and stability assessment of high-fill foundatio

关键词： High-fill engineering Wireless remote monitoring Foundation deformation Spatiotemporal law Settlement after construction

Separation and Identification of Isotopes Produced from ^(20)Ne+Be Reaction by Radioactive Ion Beam Line in lanzhou

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Chinese Physics Letters 1998年第11期15卷 790-792页

作者： SUN Zhi-yu ZHAN Wen-long GUO Zhong-yan XIAO Guo-qing WANG Jin-chuan LI Jia-xing JIANG Shan-hong MENG Xiang-wei QIN Li-jun WANG Quan-jin Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000

The separation and identification of isotopes emitted from the projectile fragmentation reaction of 80 MeV/u 20Ne on 9Be target were carried out by using the radioactive ion beam line in lanzhou(RIBLL).Many proton rich isotopes are *** intensity and purity fit the theoretical *** separation and identification abilities of RIBLL A/ΔA>300 and Q/ΔQ>150,are obtained.

关键词： MeV/u separation purity