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The Study of Minimal Period Estimates for Brake Orbits of Autonomous Subquadratic Hamiltonian Systems

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Acta Mathematica Sinica,English Series 2015年第10期31卷 1645-1658页

作者： chong LI Basic Department Beijing Union University

In this paper, we consider the minimal period estimates for brake orbits of autonomous subquadratic Hamiltonian systems. We prove that if the Hamiltonian function H ∈ C2（R2n,R） is unbounded and not uniformly coercive, there exists at least one nonconstant T-periodic brake orbit （z, T） with minimal period T or T/2 for every number T 〉 0.

关键词： Brake orbits minimal period L-Maslov type index Hamiltonian systems

Facile One-Pot Green Synthesis and Antibacterial Activities of GO/Ag Nanocomposites

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Acta Metallurgica Sinica(English Letters) 2017年第1期30卷 36-44页

作者： chong-chong Liu Hui Xu Lei Wang Xuan Qin College of Chemistry and Materials Science Ludong UniversityYantai 264025China College of Life Sciences Ludong UniversityYantai 264025China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

New materials with good antibacterial activity synthesized by simple, environmentally friendly method have attracted numerous research interests. Taking advantage of Ag and graphene oxide （GO）, the GO/Ag nanocomposites were prepared by a facile, green ＂one-pot＂ reaction to achieve superior antibacterial properties. AgNO3 is as a precursor of Ag nanoparticles （Ag NPs）, and the grape seeds extract as an environmentally friendly reducing and stabilizing agent. The asprepared GO/Ag nanocomposites were characterized by various technologies. The results indicated that the silver ion was reduced by the grade seeds extract and Ag NPs were decorated on the surface of GO nanosheets successfully. The average size of the Ag NPs anchored on the GO surface was 40-50 nm. In this study, we prepared GO/Ag nanocomposites with different Ag NPs to GO ratios and carefully investigated their antibacterial activities. We found that the GO/Ag nanocomposites show better antibacterial activity when the concentration of AgNO3 is 2 mM. GO/Ag nanocomposites have a minimum inhibitory concentration 23.8 μg/mL, lower than bare Ag NPs 25.5 μg/mL. We try to explain the antibacterial mechanism based on optical microscopy observation.

关键词： GO/Ag nanocomposites Green "one-pot" reaction Superior antibacterial properties

Numerical interpretation of transient permeability test in tight rock

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第1期10卷 32-41页

作者： chong Cao Department of Civil Engineering and Applied Mechanics McGill University

Pulse-decay method has been widely used to estimate the fluid transport properties of low-permeability geomaterials. In this context, radial flow transient pulse test is conducted to measure the water permeability of Cobourg limestone hollow cylinder. The proposed method applies hydraulic pulses to the sealed central cavity and then the cavity pressure dissipates as the fluid migrates into the saturated rock matrix. The influence of entrapped air bubbles within the pressurized cavity is crucial to interpreting permeability from transient pulse test. The modeling results indicate that the air inclusions can significantly increase the fluid compressibility and thus delay the hydraulic pulse decay process, which may lead to the underestimation of the rock permeability.

关键词： Pulse-decay method Low-permeability Air-water mixture Compressibility

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浮游藻类物候遥感监测研究进展

湖泊科学 2025年第1期37卷 1-13页

作者：严照江房冲宋开山王翔宇吕云峰中国科学院东北地理与农业生态研究所长春130102 长春师范大学地理科学学院长春130032

浮游藻类广泛分布于海洋和内陆水体生态系统中,其生长和发育过程具有明显的时空异质性,对气候变化的响应也极为复杂。藻类物候描述了其在长期适应气候、水质和人类干预等因素下的周期性变化,从而形成一种与环境条件相适应的生长发育节... 详细信息

浮游藻类广泛分布于海洋和内陆水体生态系统中,其生长和发育过程具有明显的时空异质性,对气候变化的响应也极为复杂。藻类物候描述了其在长期适应气候、水质和人类干预等因素下的周期性变化,从而形成一种与环境条件相适应的生长发育节律。它主要包括藻类的出现时间、增长高峰以及减少或消亡的时间等特征。遥感技术通过高时空分辨率持续获取叶绿素a浓度数据(浮游藻类生物量的表征参数),实现对藻类物候的长期监测。本文详细地回顾了近年来遥感藻类物候监测和提取方法的进展,指出目前存在的问题与不足,并对未来的发展趋势进行展望。首先,回顾了现有卫星遥感提供大范围时空连续的藻类生长信息。其次,总结了浮游藻类物候阶段的监测,以及估计藻类特定物候阶段的方法。同时,介绍了用于遥感时间序列估算藻类物候的常用数据处理方法,探讨了浮游藻类物候特性的变化趋势。最后,探索了可能影响藻类物候变化的因素和驱动机制。基于以上分析,本文指出未来藻类物候遥感的研究应重点关注:(1)开发并验证适用于不同水域环境的通用算法,结合机器学习等智能算法改进物候模型,提高物候监测精度和算法的业务化应用水平;(2)结合数值模型和生态系统动态模型,深入研究浮游藻类物候背后的驱动机制。

关键词：藻类物候叶绿素a 海洋和内陆水体

A comparative study of the pore characteristics and phenol adsorption performance of activated carbons prepared from oil-palm shell wastes by steam and combined steam-chemical activation

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Green Chemical Engineering 2024年第1期5卷 85-96页

作者： Aik chong Lua School of Mechanical and Aerospace Engineering Nanyang Technological University50 Nanyang AvenueSingapore639798Republic of Singapore

Oil-palm shell wastes were successfully converted into useful activated carbons in a systematic and novel approach by optimizing the pyrolysis conditions and subsequent steam activation conditions to maximize the BET surface *** optimal activation conditions were a steam flow rate of 1.13 kg/h,hold time of 1.5 h and temperature of 950℃,yielding BET areas of 1432.94 and 1382.95 m^(2)/g for nitrogen-pyrolyzed and vacuumpyrolyzed chars,*** steam-chemical activation,one-step activation of oil-palm shell in steam with potassium carbonate(K_(2)CO_(3)),sodium carbonate(Na_(2)CO_(3))or potassium chloride(KCl)was conducted,resulting in BET area output order of shell/K_(2)CO_(3)(710.56 m^(2)/g)>shell/KCl(498.55 m^(2)/g)>shell(366.7 m^(2)/g)>shell/Na_(2)CO_(3)(326.62 m^(2)/g).This study reported the first use of KCl and Na_(2)CO_(3)as chemical reagents in one-step steam-chemical activation of ***-activated carbon exhibited retardation of tar formation property,resulting in better pore development than pure steam activated *** adsorption of activated carbon is not only a function of the BET surface area but also the type of pyrolysis used prior to physical *** carbon(BET area of 1192.29 m^(2)/g)pyrolyzed under vacuum could adsorb 87%more phenol than that pyrolyzed in nitrogen flow which had a higher BET area of 1432.94 m^(2)/*** adsorption capacities of activated carbons are:shell pyrolyzed under vacuum(275.5 mg/g)>shell pyrolyzed in N_(2)flow(147.1 mg/g)>shell/K_(2)CO_(3)(145.7 mg/g)>shell without pyrolysis(12.1 mg/g).These activated carbons would be highly suitable in industry processes to remove phenolic contaminants.

关键词： Pore surface area Oil-palm shell Activated carbon Steam activation Phenol adsorption

Analysis of the anti-T2DM components in dichloromethane fraction of Schisandra sphenanthera and its mechanism

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Traditional Medicine Research 2025年第1期10卷 27-43页

作者： Shi-Bo Feng Hai-Hui Jiang Hui-Li Kang Yi Jiang Hua-Wei Zhang Xiao-Mei Song Yu-Ze Li Wen-Li Huang Dong-Dong Zhang chong Deng School of Pharmacy Shaanxi University of Chinese MedicineXianyang 712046China School of Pharmacy and Shaanxi Qinling Application Development and Engineering Center of Chinese Herbal Medicine Shaanxi University of Chinese MedicineXianyang 712046China Key Laboratory for Research and Development of“Qin Medicine”of Shaanxi Administration of Traditional Chinese Medicine Xianyang 712046China Shaanxi Key Laboratory of Research and Application of“Taibai Qi Yao” Xianyang 712046China

Background:The type 2 diabetes mellitus(T2DM)pharmacodynamic study of various parts of Schisandra sphenanthera was conducted in the previous stage,and it was found that dichloromethane extracted part(SDP)had a significant hypoglycemic ***,the components of SDP were analyzed,and the specific mechanism of its anti-T2DM was ***:We used a high-fat,high-sugar diet in combination with streptozotocin to induce a T2DM rat model,and the model rats were divided into two groups according to body weight and blood ***,oral glucose tolerance test,fasting blood glucose,low density lipoprotein cholesterol,superoxide dismutase,insulin,glycated hemoglobin,total cholesterol,nonesterified free fatty acids,alanine aminotransferase,high-density lipoprotein cholesterol,aspartate aminotransferase,malondialdehyde,and glutathione peroxidase were measured,organ indices were calculated,and pathological sections of pancreas and liver were *** 16S rRNA V3–V4 region of intestinal flora was sequenced to explore the effect of SDP on biochemical indicators and intestinal *** on the above indicators,the anti-T2DM mechanism of SDP in Schisandra sphenanthera was ***:After six weeks of administration,the biochemical indices of diabetic rats were diminished compared to the control *** SDP could significantly increase the gut microbialα-diversity index,resulting in significant changes in the flora of T2DM rats,with increased richness and diversity,reduced harmful flora,and significantly back-regulated the levels of acetic acid,propionic acid,and butyric ***:SDP can improve the symptoms associated with elevated blood glucose,dyslipidemia,elevated fasting insulin levels,and damaged glucose tolerance in *** against T2DM may be through the control of intestinal flora to normalize and exert anti-diabetic effect;its main active components may be lignans and terpenoids.

关键词： Schisandra sphenanthera T2DM intestinal flora HPLC

Temperature variation characteristics in flocculation settlement of tailings and its mechanism

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1438-1448页

作者： Dao-lin Wang Qin-li Zhang Qiu-song Chen chong-chong Qi Yan Feng chong-chun Xiao School of Resources and Safety Engineering Central South UniversityChangsha 410083China Feny Co. Ltd.Changsha 410083China Sinosteel Maanshan Institute of Mining Research Company Limited Maanshan 243000China

Rapid flocculation and settlement(FS)of mine tailings is significant for the improvement and development of the filling process,whereas the settlement velocity(SV)of tailings in FS has been recognized as a key parameter to evaluate the settlement ***,the influence of temperature on the SV and its mechanism have not been *** experiments on tailings with various ambient temperatures were carried *** SVs of tailings with a solid waste content of 10wt%and an anionic polyacrylamide content of 20 g·t^−1 were measured at different *** SV presented an“N”-shaped variation curve as the temperature changed from 5 to 40℃.The mechanism of these results can be explained from the perspective of the electric double-layer repulsive force,molecular dynamics,and the polymer flocculation principle,as revealed from the scanning electron microscopy of floc *** findings will be beneficial in the design of tailings dewatering processes and save costs in the production of cemented paste backfill.

关键词： cemented paste backfill tailing dewatering flocculation settlement temperature

CONVERGENCE OF NEWTON＇S METHOD FOR SYSTEMS OF EQUATIONS WITH CONSTANT RANK DERIVATIVES

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Journal of Computational Mathematics 2007年第6期25卷 705-718页

作者： Xiubin Xu chong Li Department of Mathematics Zhejiang Normal University Jinhua 321004 China Department of Mathematics Zhejiang University Hangzhou 310027 China

The convergence properties of Newton＇s method for systems of equations with constant rank derivatives are studied under the hypothesis that the derivatives satisfy some weak Lipschitz conditions. The unified convergence results, which include Kantorovich type theorems and Smale＇s point estimate theorems as special cases, are obtained.

关键词： Newton's method Overdetermined system Lipschitz condition with L average,Convergence Rank.

Power Requirements of Vertical Flight in the Dronefly

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Journal of Bionic Engineering 2015年第2期12卷 227-237页

作者： chong Shen Mao Sun Institute of Fluid Mechanics Beijing University o[Aeronautics & Astronautics Beijing 100191 China

Power requirements in vertical flight in the dronefly （Eristarlis tenax; also known as hoverfly） are studied using the metnoa of computational fluid dynamics. The flow solution provides the aerodynamic forces and torques; the inertial torques due to the acceleration of the wing-mass are computed analytically. From the aerodynamic and inertial torques, the mechanical power is obtained. It has been shown that at hovering flight, the specific power with 100% elastic energy storage is 43.51 *** · and that without elastic energy storage is 60.12 W·kg-1. During vertical flight, the specific power increases with the ascending ratio K （ratio of the ascending velocity to the tip velocity）; it is proportional to K to the power of about 1.37. When flying upward at an ascending ratio of about 0.3, the power required is the same as that when the insect carries a load of about 50% of its weight.

关键词： insect upward flying Navier-Stokes simulation flight balance flight power