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Chip morphology and cutting temperature of ADC12 aluminum alloy during high-speed milling

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Rare Metals 2021年第7期40卷 1915-1923页

作者： xin-xin Meng You-xi lin School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China

The ADC12 aluminum alloy is prone to severe tool wear and high cutting heat during high-speed milling because of its high *** study analyzes the highspeed milling process from the perspective of different chip *** influence of cutting temperature on chip morphology was expounded.A two-dimensional orthogonal cutting model was established for finite element analysis(FEA)of high-speed milling of ADC12 aluminum alloy.A theoretical analysis model of cutting force and cutting temperature was proposed based on metal cutting *** variations in chip shape,cutting force,and cutting temperature with cutting speed increasing were analyzed via *** results show that,with the increase in cutting speed,the chip morphology changes from continuous to serrated,and then back to *** serrated chip is weakened and the cutting temperature is lowered when the speed is lower than 600 m·min^(-1)or higher than 1800 m·min^(-1).This study provides a reference for reducing cutting temperature,controlling chip morphology and improving cutting tool life.

关键词： ADC12 aluminum alloy High-speed milling Chip morphology Cutting temperature Finite element analysis

Explicit Solutions of (2+1)-Dimensional Canonical Generalized KP, KdV, and (2+1)-Dimensional Burgers Equations with Variable Coefficients

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Communications in Theoretical Physics 2009年第11期52卷 784-790页

作者： ZHANG lin-lin LIU xi-Qiang School of Mathematical Sciences Liaocheng University Liaocheng 252059 China

In this paper, using the generalized （G1/G）-expansion method and the auxiliary differential equation method, we discuss the （2＋1）-dimensional canonical generalized KP （CGKP）, KdV, and （2＋1）-dimensional Burgers equations with variable coetticients. Many exact solutions of the equations are obtained in terms of elliptic functions, hyperbolic functions, trigonometric functions, and rational functions.

关键词： generalized (G1/G)-expansion method auxiliary equation exact solution

Impact of the COVID-19 pandemic on agricultural exports

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Journal of Integrative Agriculture 2020年第12期19卷 2937-2945页

作者： lin Ben-xi Yu Yvette ZHANG School of Economics Fujian Agriculture and Forestry UniversityFuzhou 350002P.R.China Department of Agricultural Economics Texas A&M UniversityCollege StationTX 77843USA

The COVID-19 outbreak has shocked the world’s economies in the year of *** this pandemic spreads around the globe,many experts feared that the global food supplies might start running short,especially if supply chains were ***-19 also added to the uncertainty of the business ***,it is critical to understand how COVID-19 pandemic affected global food supply and *** this study,we investigate the impact of COVID-19 on agricultural export companies in China using a unique firm-level survey *** found that although on average agricultural businesses experienced declines in the exports,exports of some agricultural products especially grain and oil held strong and even increased,implying the essential demand for staple food during the *** surprisingly,exports of medicinal herb also increased significantly during the ***,exports of goods such as edible fungus and horticultural products sharply *** results also showed that in general,impact of COVID-19 on smaller firms was more severe than that on larger *** results of this study can provide useful guidance and implications for agricultural businesses and policy makers on their COVID-19 mitigation efforts to navigate this global pandemic.

关键词： COVID-19 pandemic agricultural exports business survey international trade China

RATE OF INTRA-MOLECULAR CONTACT FORMATION IN SHORT TWO-DIMENSIONAL COMPACT POLYMERS CHAINS

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Chinese Journal of Polymer Science 2006年第1期24卷 13-19页

作者： Jin Chen lin-xi Zhang A-gen xia Department of Physics Zhejiang University Hangzhou 310027 China Department of Physics Wenzhou Normal College Wenzhou 325027 China

It is important to know the rate of intra-molecular contact formation in proteins in order to understand how proteins fold clearly. Here we investigate the rate of intra-molecular contact formation in short two-dimensional compact polymer chains by calculating the probability distribution p（r） of end-to-end distance r using the enumeration calculation method and HP model on two-dimensional square lattice. The probability distribution of end-to-end distance p（r） of short two-dimensional compact polymers chains may consist of two parts, i.e. p（r） = p1（r）＋ p2（r）, where p1（r） and p2（r） are different for small r. The rate of contact formation decreases monotonically with the number of bonds N, and the rate approximately conforms to the scaling relation of k（N）∝ N^-α. Here the value of α increases with the contact radius a and it also depends on the percentage of H （hydrophobic） residues in the sequences of compact chains and the energy parameters of ^εНН、 ^εНН and ^εpp. Some comparisons of theoretical predictions with experimental results are also made. This investigation may help us to understand the protein folding.

关键词： Two-dimensional compact polymer HP model Rate of contact formation.

Translocation of Polymer Chains Through a Channel with Complex Geometries

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Chinese Journal of Chemical Physics 2008年第6期21卷 555-559页

作者： Zhi-yong Yang lin-xi Zhang Jun Cheng Department of Physics Wenzhou University Wenzhou 325027 China

The elastic behavior of a single chain transporting through complex channel which can be seen as the combination of three different channels （left channel, middle channel, and right channel, respectively） is investigated using the new pruned-enriched Rosenbluth method with importance sampling. The elastic force during the translocation process is calculated. At the entrance into the middle channel, there is the first plateau in the curve of the elastic force f （f〉0） versus x, here x represents the position of the first monomer along the x-axis direction. When the first monomer moves to a certain position, a second plateau is observed with the elastic force f〈0, which represents spontaneous translocation. The free energy difference between the subchain in the right channel and the subchain in the left channel may drive the transloeation. The influence of chain length and width of the left and right channels on the translocation process are also investigated. From the simulation results, more detailed explanations for the reason why the component translocation time is not the same for different channels can be presented.

关键词： Elastic behavior nPERMis Polymer translocation

Exact Solutions to (2+1)-Dimensional Kaup-Kupershmidt Equation

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Communications in Theoretical Physics 2009年第11期52卷 795-800页

作者： LU Hai-lin LIU xi-Qiang School of Mathematical Sciences Liaocheng University Liaocheng 252059 China

In this paper, by using the symmetry method, the relationships between new explicit solutions and old ones of the （2＋1）-dimensional Kaup-Kupershmidt （KK） equation are presented. We successfully obtain more general exact travelling wave solutions for （2＋ 1）-dimensional KK equation by the symmetry method and the （G1/G）-expansion method. Consequently, we find some new solutions of （2＋1）-dimensional KK equation, including similarity solutions, solitary wave solutions, and periodic solutions.

关键词： (2+1)-dimensional Kaup-Kupershmidt equation the symmetry method the (G1/G)-expansion method exact solutions

Transplacental induction of fatty acid oxidation in term fetal pigs by the peroxisome proliferator-activated receptor alpha agonist clofibrate

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Journal of Animal Science and Biotechnology 2016年第3期7卷 341-352页

作者： xi lin Sheila Jacobi Jack Odle Laboratory of Developmental Nutrition Department of Animal SciencesNorth Carolina State University

Background： To induce peroxisomal proliferator-activated receptor α（PPARα） expression and increase milk fat utilization in pigs at birth, the effect of maternal feeding of the PPARα agonist, clofibrate（2-（4-chlorophenoxy）-2-methyl-propanoic acid, ethyl ester）, on fatty acid oxidation was examined at ful-term delivery（0 h） and 24 h after delivery in this *** group of pigs（n = 10） was delivered from pregnant sows fed a commercial diet with or without 0.8% clofibrate for the last 7 d of gestation. Blood samples were col ected from the utero-ovarian artery of the sows and the umbilical cords of the pigs as they were removed from the sows by C-section on day 113 of ***： HPLC analysis identified that clofibric acid was present in the plasma of the clofibrate-fed sow（~4.2 μg/m L）and its offspring（~1.5 μg/m L）. Furthermore, the maternal-fed clofibrate had no impact on the liver weight of the pigs at 0 h and 24 h, but hepatic fatty acid oxidation examined in fresh homogenates showed that clofibrate increased（P 〈 0.01）^14C-accumulation in CO2 and acid soluble products 2.9-fold from [1-^14C]-oleic acid and 1.6-fold from[1-^14C]-lignoceric acid respectively. Correspondingly, clofibrate increased fetal hepatic carnitine palmitoyltransferase（CPT）and acyl-Co A oxidase（ACO） activities by 36% and 42% over controls（P 〈 0.036）. The m RNA abundance of CPT I was 20-fold higher in pigs exposed to clofibrate（P 〈 0.0001） but no differences were detected for ACO and PPARα m RNA between the two ***： These data demonstrate that dietary clofibrate is absorbed by the sow, crosses the placental membrane, and enters fetal circulation to induce hepatic fatty acid oxidation by increasing the CPT and ACO activities of the newborn.

关键词： Clofibrate Fatty acid oxidation Pigs Placenta transfer

糖尿病足伴慢性骨髓炎大鼠模型建立的分析与展望

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动物医学进展 2025年第1期46卷 109-113页

作者：焦琳茜徐旭英张博蔺莉马逸朝刘威池首都医科大学附属北京中医医院北京100010

糖尿病足伴慢性骨髓炎是一种常见的糖尿病并发症,具有较高的截肢率及致死率,目前缺乏可靠的治疗手段。建立成熟的糖尿病足伴慢性骨髓炎模型可促进治疗手段的进一步研发。根据糖尿病和骨髓炎各自的类型及成因,已有多种造模方法供研究选择... 详细信息

糖尿病足伴慢性骨髓炎是一种常见的糖尿病并发症,具有较高的截肢率及致死率,目前缺乏可靠的治疗手段。建立成熟的糖尿病足伴慢性骨髓炎模型可促进治疗手段的进一步研发。根据糖尿病和骨髓炎各自的类型及成因,已有多种造模方法供研究选择,但目前尚未出现关于糖尿病足骨髓炎动物模型的研究报道。论文就骨髓炎模型以及糖尿病模型制备方法方面的研究进展进行综述,提出了建立糖尿病足伴慢性骨髓炎大鼠模型方法,并分析各类模型的优缺点,旨在为建立一种用于研究糖尿病足骨髓炎的动物模型奠定基础。

关键词：糖尿病足伴慢性骨髓炎糖尿病骨髓炎动物模型大鼠

Density enhancement mechanism of upwind schemes for low Mach number flows

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Acta Mechanica Sinica 2018年第3期34卷 431-445页

作者： Bo-xi lin Chao Yan Shu-Sheng Chen School of Aeronautic Science and Engineering Beihang University

Many all-speed Roe schemes have been proposed to improve performance in terms of low speeds. Among them, the F-Roe and T-D-Roe schemes have been found to get incorrect density fluctuation in low Mach flows, which is expected to be with the square of Mach number. Asymptotic analysis presents the mechanism of how the density fluctuation problem relates to the incorrect order of terms in the energy equation paU△U. It is known that changing the upwind scheme coefficients of the pressure-difference dissipation term DP and the velocity-difference dissipation term in the momentum equation DPU to the order of O （c- 1） and O（c0） can improve the level of pressure and velocity accuracy at low speeds. This paper shows that corresponding changes in energy equation can also improve the density accuracy in low speeds. We apply this modification to a recently proposed scheme, TV-MAS, to get a new scheme, TV-MAS2. Unsteady Gresho vortex flow, double shear-layer flow, low Mach number flows over the inviscid cylinder, and NACA0012 airfoil show that energy equation modification in these schemes can obtain the expected square Ma scaling of density fluctuations, which is in good agreement with corresponding asymptotic analysis. Therefore, this density correction is expected to be widely implemented into allspeed compressible flow solvers.

关键词： Energy equation Density fluctuation Roe TV-MAS Low speeds All speeds Computational fluid dynamics