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Lei Lu,Jiang Han,Lian Xia,Cheng Fan,Haijun Liu,Shan Chen 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.10
To improve the application of the parametric curve tool path in surface machining, a method for generating arc-length parameterized toolpaths based on short-line toolpaths is proposed. The method first uses commercial CAM software to plan the short-line tool path. Then, the machining tool path with smooth continuous features is extracted. The smooth and continuous features are determined according to the chord length of the short-line tool path, and the extraction method is based on Chebyshev’s inequality of large numbers. After obtaining the smooth short-line trajectory, the iterative arc-length parameterized curve toolpath generation method is used to fit the discrete short-line toolpath. In the iterative process, the B-spline toolpath with parameterized chord length is obtained first. It is discretized according to the arc length difference information of the chord length B-spline. Finally, by continuously checking and inserting B-spline nodes, and fitting according to discrete points, the arc-length parameterized B-spline tool path is obtained. The feasibility of the method is verified with a part containing a sculpted surface, and two smooth arc-length parametric toolpaths are generated. In the end, the part is machined with the arc-length parameterized curve tool path.
SNPs in the coding region of bovine MGAT2 gene are associated with body weight and weight gain
Lian Qu,Mingjuan Yang,Jinlong Zhu,Junxia Liu,Mijie Li,Liangzhi Zhang,Xianyong Lan,Chuzhao Lei,Chunlei Zhang,Hong Chen 한국유전학회 2011 Genes & Genomics Vol.33 No.3
Monoacylglycerol acyltransferase 2 (MGAT2), as a candidate gene for quantitative traits, relates to dietary fat uptake, lipids synthesis and storage, which plays a major role in the absorption of dietary fat by catalyzing the resynthesis of triacylglycerol in enterocytes. In this study, based on DNA pool sequencing and PCR‐RFLP methods, polymorphisms of the MGAT2 gene were detected in 1145 Chinese indigenous cattle. The results revealed two novel mutations located on exon 1and exon 5 (NM_001099136.1:m.84G>T and 756A>G). Hence, we described the HaeIII forced PCR–RFLP method in exon1 and a MluI PCR–RFLP method in exon5 to detect them. In addition, the associations of these polymorphisms with growth traits were evaluated in Nanyang cattle. The results showed that only HaeIII locus was associated with body weight and average daily gain aged 6 months, and individuals with genotype TT showed significantly higher body weight and average daily gain than those with genotype GG.
Zhiping Lei,Hengfu Shui,Lian Wu,Lijuan Gao,Muxin Liu,Zhicai Wang,Shibiao Ren 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5
NaOH depolymerized products (SDP) of Shengli lignite was used as lignite-based heavy carbon resources in this study. Hydrotreatment of SDP over Ni–Mo/Al2O3 and Ni–Mo/Zr–Al2O3 catalysts was investigated. It was found that the incorporation of Zr to Ni–Mo/Al2O3 catalyst results in the easy reduction of metal oxides and the increase of the stacking degree and length of MoS2 slabs. Both of Ni–Mo/Al2O3 and Ni–Mo/Zr–Al2O3 catalysts show better performance for hydrogenation of SDP and can be used repeatedly. The incorporation of Zr to Ni–Mo/Al2O3 catalyst significantly inhibits the formation of tetrahydrofuran insolubles (THFI), promotes the formation of two-ring aromatics and increases HS yield compared to that over Ni–Mo/Al2O3 catalyst.
Yunsong Lian,Huifeng Chen,Chenliang Mu,Jianxin Deng,Shuting Lei 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.2
A new dry cutting tool named WS2 soft coated Micro-Nano textured self-lubricating dry cutting tool (WTT tool) is developed and tested. Dry turning tests have been carried out on 45# quenched and tempered steel with a WTT tool and three other types of alternative tools. The machining performance was assessed in terms of the cutting forces, cutting temperature, friction coefficient at the tool-chip interface, chip deformation, tool wear, and the surface roughness of the machined workpiece. The results show that the WTT tool has the best cutting performance among all the tools tested under the same cutting conditions. Through theoretical analysis and experimental results, the mechanisms of the WTT tool in improving cutting performance were put forward. Meanwhile, the effect of Micro-Nano texture and WS2 soft coating on the cutting forces and the cutting temperature is analyzed. It can be concluded that the WTT tool can effectively improve the anti-adhesion and wear-resistance properties and increase the tool life.
Li, Lei,Zeng, Gui-Sheng,Luo, Sheng-Lian,Deng, Xiao-Rong,Xie, Qing-Ji 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.2
The influences of solution pH and redox potential on bioleaching of $LiCoO_2$ from spent lithium-ion batteries using Acidithiobacillus ferrooxidans were investigated. Bioleaching at different initial pH and ferrous ion ($Fe^{2+}$) concentrations were carried out, and electrochemical behavior of $LiCoO_2$ dissolution was examined to study the effect of solution redox potential on the bioleaching process. The results showed maximum cobalt dissolution at initial pH of 1.5 and initial $Fe^{2+}$ concentration of 35 g/L, and cobalt dissolution showed only slight relationship with pH of solution. Nonetheless, there was improvement of cobalt dissolution at higher redox potential. The cyclic voltammograms showed that dissolution rates increase when the solution potentials are higher than 0.4 V, and rapid decrease at 1.3 V. The anodic polarization curves indicated that the corrosion, primary passive, and passivation potentials were 0.420, 0.776 and 0.802 V, respectively.
Tang, Lian Sheng,Chen, Hao Kun,Sun, Yin Lei,Zhang, Qing Hua,Liao, Hua Rong Techno-Press 2018 Geomechanics & engineering Vol.16 No.2
Under repeated loading, the residual stresses within the subgrade and subsoil can accelerate the deformation of the road structures. In this paper, a series of laboratory cyclic loading model tests and small-scale model tests were conducted to investigate the dynamic stress response within soils under different loading conditions. The experimental results showed that a dynamic stress accumulation effect occurred if the soil showed cumulative deformation: (1) the residual stress increased and accumulated with an increasing number of loading cycles, and (2) the residual stress was superimposed on the stress response of the subsequent loading cycles, inducing a greater peak stress response. There are two conditions that must be met for the dynamic stress accumulation effect to occur. A threshold state exists only if the external load exceeds the cyclic threshold stress. Then, the stress accumulation effect occurs. A higher loading frequency results in a higher rate of increase for the residual stress. In addition to the superposition of the increasing residual stress, soil densification might contribute to the increasing peak stress during cyclic loading. An increase in soil stiffness and a decrease in dissipative energy induce a greater stress transmission within the material.
Zhengwei Luo,Lei Li,Mulin Guo,Hui Jiang,Wenhua Geng,Wuji Wei,Zhouyang Lian 한국섬유공학회 2020 Fibers and polymers Vol.21 No.12
In this work, a new strategy was developed to prepare Cr(VI)-imprinted polypropylene (PP) fibers-based materialsfor the adsorption of Cr(VI) from water. Granular PP was modified with dual monomers (glycidyl methacrylate (GMA) andacrylamide (AM)) by water-solid suspension grafting copolymerization. Then, this fibers morphology was obtained by meltblowing. Hence, the preparation steps of the fibrous Cr(VI)-imprinted adsorbent involved surface ion-imprinting andcrosslinking. The influence of the grafting conditions on the grafting percentage was investigated. The maxima graftingpercentages of GMA and AM were 16.4 and 10.6 %, respectively. The chemically modified products showed good mobilityand stability, thus meeting the requirements of melt-blowing method. The prepared Cr(VI)-imprinted polymers showed amaximum adsorption capacity to Cr(VI) of 43.2 mg/g at pH 3. The adsorption data were well fitted by the pseudo-secondorderand Langmuir adsorption models. The adsorbent showed good selectively toward Cr(VI) in a mixed solution containingCu(II) and SO42−. The X-ray photoelectron spectroscopy demonstrated that the adsorbed Cr(VI) was partly reduced to Cr(III).
Yujie Zhao,Yeda Lian,Lei Li,Xu Gong,Xianghai Chai,Wei Liu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2
Pre-swirl nozzle is an important cooling component that is located inside of aero-engine and exposed to complex vibration excitation, and exploring its vibration characteristics and durability is of significant importance, especially for 3D printing pre-swirl nozzle. The present study provides a novel vibration test method based on equivalent installation stiffness. Firstly, the vibration characteristics of pre-swirl nozzle in real engine assembly state is calculated by the finite element method, and the equivalent constraint fixture is designed and checked based on this. The check results indicate that the designed fixture can well restore the installation stiffness of engine and the strength of the test fixture elements is enough in the vibration test process. Then, the modal characteristics of pre-swirl nozzle are measured by modal test, based on which the accuracy of the finite element model is verified. Finally, a test program of vibration durability is established to evaluate the vibration durability of pre-swirl nozzle, in which the excitation frequency is determined by combining logarithmic frequency sweep and linear frequency sweep and the location of maximum stress is determined based on a novel method (density increasing method). Besides, the calibration of relation between vibration stress and excitation amplitude is completed. Based on the proposed test program, vibration durability test is performed. The results show that the natural frequency of pre-swirl nozzle only decreases by 0.62 % after 5×10 7 cycles, which indicates that the specimen is always in the stage of fatigue crack initiation over the test duration.