Cutting force, tool wear and surface roughness in high-speed milling of high-strength steel with coated tools

Yuan Li,Guangming Zheng,Xu Zhang,Xiang Cheng,Xianhai Yang,Rufeng Xu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

The TiAlN+TiN coated tool, AlTiN coated tool and TiN/TiCN/TiAlN multi-coated tool were chosen for the high-speed milling of AISI 4340. The resultant cutting force and tool wear of coated tools were reviewed. The influence of cutting parameters and coating materials on the machined surface roughness was studied. The smallest resultant cutting force was obtained by TiN/TiCN/TiAlN multicoated tool. The main wear mechanisms of coated tool were chipping, collapse, the chipping of coating, adhesive wear, abrasive wear and crater wear. The minimal flank wear width was obtained by TiN/TiCN/TiAlN multi-coated tool. Among the selected cutting parameters, the lower surface roughness R a of 0.08~0.32 μm was achieved by the TiN/TiCN/TiAlN multi-coated tool and TiAlN+TiN coated tool. This work was conducive to the selection of coated tools and the optimization of cutting parameters in high-speed milling of AISI 4340, as well as to the promotion of high-efficiency and high-quality machining of hard-to-cut material.

Enhancing the Anaerobic Digestion of Corn Stalks Using Composite Microbial Pretreatment

( Xu Feng Yuan ),( Pei Pei Li ),( Hui Wang ),( Xiao Fen Wang ),( Xu Cheng ),( Zong Jun Cui ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.7

A composite microbial system (XDC-2) was used to pretreat and hydrolyze corn stalk to enhance anaerobic digestion. The results of pretreatment indicated that sCOD concentrations of hydrolysate were highest (8,233 mg/l) at the fifth day. XDC-2 efficiently degraded the corn stalk by nearly 45%, decreasing the cellulose content by 22.7% and the hemicellulose content by 74.1%. Total levels of volatile products peaked on the fifth day. The six major compounds present were ethanol (0.29 g/l), acetic acid (0.55 g/l), 1,2-ethanediol (0.49 g/l), propionic acid (0.15 g/l), butyric acid (0.22 g/l), and glycerine (2.48 g/l). The results of anaerobic digestion showed that corn stalks treated by XDC-2 produced 68.3% more total biogas and 87.9% more total methane than untreated controls. The technical digestion time for the treated corn stalks was 35.7% shorter than without treatment. The composite microbial system pretreatment could be a cost-effective and environmentally friendly microbial method for efficient biological conversion of corn stalk into bioenergy.

Volatilization of Nerolidol in Tea and Tea-soup

Yuan-Xu Shi,Ya-Ting Lu,Jie Lin,Xiao-Chang Wang 한국차학회 2015 한국차학회지 Vol.- No.S

Nerolidol is one of most important content in tea aroma, especially in Oolong tea. This experiment focuses on the impact of time and medium on nerolidol volatilization. The results of nerolidol volatilization with infusion time showed that the peak areas of nerolidol increased from 1 to 3 min, then decreased. The maximum peak area of nerolidol volatilization was 25630.78 at 3 min. Tea polyphenol had strong promotion impact on fragrant compound volatize, caffeine had limited impact on volatilization, while polysaccharide inhibited nerolidol volatilization.

Multi-loop current control strategy based on predictive control for multiphase pulse power supplies

Yuan, Zhibao,Wen, Pingping,Xu, Haiping,Yuan, Zengquan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.3

For high-power quasi-continuous laser drivers, the switched pulse power supply (PPS) is a promising technique due to its higher efficiency when compared with linear drivers. However, there are some digital control challenges with high precision, fast response and zero overshoot during the flat-top current stage. To promote the use of a switched PPS, this paper proposes a digital control strategy based on predictive current control under a multiphase PPS converter circuit. The key of the proposed control strategy is that predictive inner current control is only used for the master phase circuit. Meanwhile, the current sharing control is used for balancing the phase currents, and the setting outer current controller is used for keeping the whole converter control system stable and robust. Furthermore, to obtain fast and precise current tracking, a predictive average current control independent from the load values is derived. Moreover, a reducing gain method is applied to guarantee the stability of the inner current control. When compared with the conventional multiphase control, the proposed strategy possesses a faster dynamic response and a higher accuracy. In addition, it is more flexible under digital control implementation. A 360 W dual-interleaved PPS prototype is utilized for verifying the effectiveness of the proposed control strategy.

Arachidonic Acid 15-Lipoxygenase: Effects of Its Expression, Metabolites, and Genetic and Epigenetic Variations on Airway Inflammation

Xu Xu,Li Jingyun,Zhang Yuan,Zhang Luo 대한천식알레르기학회 2021 Allergy, Asthma & Immunology Research Vol.13 No.5

Arachidonic acid 15-lipoxygenase (ALOX15) is an enzyme that can oxidize polyunsaturated fatty acids. ALOX15 is strongly expressed in airway epithelial cells, where it catalyzes the conversion of arachidonic acid to 15-hydroxyeicosatetraenoic acid (15-HETE) involved in various airway inflammatory diseases. Interleukin (IL)-4 and IL-13 induce ALOX15 expression by activating Jak2 and Tyk2 kinases as well as signal transducers and activators of transcription (STATs) 1/3/5/6. ALOX15 up-regulation and subsequent association with phosphatidylethanolamine-binding protein 1 (PEBP1) activate the mitogen-activated extracellular signal-regulated kinase (MEK)-extracellular signal-regulated kinase (ERK) pathway, thus inducing eosinophil-mediated airway inflammation. In addition, ALOX15 plays a significant role in promoting the migration of immune cells, such as immature dendritic cells, activated T cells, and mast cells, and airway remodeling, including goblet cell differentiation. Genome-wide association studies have revealed multiple ALOX15 variants and their significant correlation with the risk of developing airway diseases. The epigenetic modifications of the ALOX15 gene, such as DNA methylation and histone modifications, have been shown to closely relate with airway inflammation. This review summarizes the role of ALOX15 in different phenotypes of asthma, chronic obstructive pulmonary disease, chronic rhinosinusitis, aspirin-exacerbated respiratory disease, and nasal polyps, suggesting new treatment strategies for these airway inflammatory diseases with complex etiology and poor treatment response.

Hydrothermal Synthesis of Hexagonal MoO3 and Its Reversible Electrochemical Behavior as a Cathode for Li-Ion Batteries

Yuan-Dong Xu,Ling-Ling Xie,Yu-Jun Zhang,Xiao-Yu Cao 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.5

Hexagonal molybdenum trioxide (h-MoO3) nanoparticles with a particle size of several tens of nanometers were prepared from sodium molybdate (Na2MoO4) using hydrothermal synthesis and ultrasonication. The morphology, structure, composition, and chemical states of the nanoparticles were characterized by x-ray diffraction,field-emission scanning electron microscopy, and Fourier transform-infrared spectroscopy. Cyclic voltammetry results showed a strong reduction peak, which indicated a lithium ion insertion/extraction mechanism. The plateau observed in the first discharge curve around 1.8 V was in accordance with the above mechanism,which was also verified by differential capacity measurements. Cycling performance results showed that the capacity retention was up to 90% in the second cycle and that the irreversible capacities decreased with subsequent cycles.

Synthesis and characterization of monodisperse yttrium aluminum garnet (YAG) micro-crystals with rhombic dodecahedron

Xu, Tao,Yuan, Rui,Xu, Peng-Cheng,Pan, Dong-Jie,Yang, Woochul,Guo, Hai-Bo,Shen, Yu-Fang,Hu, Jian-Feng,Zhang, Zhi-Jun,Zhao, Jing-Tai Elsevier 2018 Journal of alloys and compounds Vol.762 No.-

<P><B>Abstract</B></P> <P>Uniform, monodisperse yttrium aluminum garnet (YAG) rhombic dodecahedron micro-crystals were synthesized using coprecipitation and hydrothermal methods. The Na<SUB>2</SUB>SO<SUB>4</SUB> as a surfactant was helpful in improving the dispersity of the crystallites and forming well-faceted, micro-sized dodecahedral YAG crystallites. The effect of the reaction time and the solvent has also been studied. The crystal growth mechanism called dissolution/crystallization was determined by analyzing the experimental and simulated results. And the specific well-developed crystal facets in the {110} family have been demonstrated by the theoretical calculation. A higher integrated emission intensity can be achieved for the YAG:Ce crystallites by improving the phase purity, morphology with better developed dodecahedrons, and dispersion. Furthermore, a rather high luminous efficacy (LE = 104.14 lm/W) for the white LED fabricated using the YAG:Ce<SUP>3+</SUP> phosphor prepared in this work was realized. The correlation between the crystal growth, morphology and luminescence properties of YAG crystallites has been established, which exhibits a great importance for the synthesis and application of mono-dispersed YAG crystallites.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Uniform and monodisperse YAG rhombic dodecahedron micro-crystals were synthesized. </LI> <LI> The growth mechanism of YAG rhombic dodecahedron was studied through experimental and computational simulation. </LI> <LI> The correlation between the crystal growth, morphology and luminescence of YAG crystallites was established. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

How to evaluate the adequacy of staging for nodal-negative epithelial ovarian cancer? Use of nodal staging score

Yuan Xu,Haoran Li,Xiaoxia Tong,Yangyang Pang,Xiaojuan Tong,Luhong Li,Lei Cheng 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.2

Objective: No guideline has been provided to assess the minimal number of lymph nodes (LNs) that should be dissected for accurate staging in patients with epithelial ovarian cancer (EOC). The aim of the study was to develop a nodal staging score (NSS) as an index to assess whether a pathologic (p)N0 EOC patient is indeed free of a nodal disease. Methods: A total of 16,361 EOC patients staged I–III between 2004 and 2013 were identified from the Surveillance, Epidemiology and End Result database. With a β-binomial model, NSS was calculated to assess the probability of true-negative findings of LN status. Results: With an increased number of LNs examined, the probability of missing a nodal disease decreased and varied among different pT stages. Given 1 LN examined, an NSS of 93.76% calculated could ensure a high adequacy of nodal-negative classification for pT1N0 EOC patients. For pT2N0 patients, 5 LNs examined could guarantee an NSS of 90% for adequate staging. Likewise, 11 and 29 LNs examined in pT3N0 patients could maintain NSS at the level of 80% and 90%, respectively. Our study suggested the optimal number of LNs that could be examined and stratified by the pT stages for EOC patients based on this statistical model derived from large pathologic data of clinical surgery patients. Conclusion: NSS, as an auxiliary tool, not only could assist the International Federation of Gynecology and Obstetrics staging more precisely, but also would provide a statistical basis for postoperative evaluation for further clinical decision-making.

An Efficient Method for Electron-Atom Scattering Using Ab-initio Calculations

Yuan Xu,Yonggang Yang,Liantuan Xiao,Suotang Jia 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.4

We present an efficient method based on ab-initio calculations to investigate electron-atom scatterings. Those calculations profit from methods implemented in standard quantum chemistry programs. The new approach is applied to electron-helium scattering. The results are compared with experimental and other theoretical references to demonstrate the efficiency of our method.

Enhancing the static behavior of laminated composite plates using a porous layer

Yuan Yuan,Ke Zhao,Kuo Xu 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.6

The main aim of this paper is enhancing design of traditional laminated composite plates subjected to static loads. In this regard, this paper suggests embedding a lightweight porous layer in the middle of laminated composite as the core layer of the resulted sandwich plate. The static responses of the suggested structures with uniform, symmetric and non-symmetric porosity distributions are compared to optimize their design. Using the first order shear deformation theories, the static governing equations of the suggested laminated composite plates with a porous layer (LCPPL) rested on two-parameter foundation are obtained. A finite element method is also utilized to solve the governing equations of LCPPLs. Effects of laminated composite and porosity characteristics as well as geometry dimension, edges’ boundary conditions and foundation coefficients on the static deflection and stress distribution of the suggested composite plates have been investigated. The results reveal that the use of core between the layers of laminated composites leads to a sharp reduction in the static deflections of LCPPLs. Furthermore, in compare with perfect cores, the use of porous core between the layers of laminated composite plates can offer a considerable reduction in structural weight without a significant difference in their static responses.