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Constitutive Modeling for Ti-6Al-4V Alloy Machining Based on the SHPB Tests and Simulation

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Chinese Journal of Mechanical Engineering 2016年第5期29卷 962-970页

作者： CHEN Guang ke Zhihong REN Chengzu LI jun key Laboratory of Equipment Design and Manufacturing Technology Tianjin University key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin University

A constitutive model is critical for the prediction accuracy of a metal cutting simulation. The highest strain rate involved in the cutting process can be in the range of 104-106 s 1. Flow stresses at high strain rates are close to that of cutting are difficult to test via experiments. Split Hopkinson compression bar （SHPB） technology is used to study the deformation behavior of Ti-6Al-4V alloy at strain rates of 10 -4-10 4s- 1. The Johnson Cook （JC） model was applied to characterize the flow stresses of the SHPB tests at various conditions. The parameters of the JC model are optimized by using a genetic algorithm technology. The JC plastic model and the energy density-based ductile failure criteria are adopted in the proposed SHPB finite element simulation model. The simulated flow stresses and the failure characteristics, such as the cracks along the adiabatic shear bands agree well with the experimental results. Afterwards, the SHPB simulation is used to simulate higher strain rate（approximately 3 × 10 4 s -1） conditions by minimizing the size of the specimen. The JC model parameters covering higher strain rate conditions which are close to the deformation condition in cutting were calculated based on the flow stresses obtained by using the SHPB tests （10 -4 - 10 4 s- 1） and simulation （up to 3 × 10 4 s - 1）. The cutting simulation using the constitutive parameters is validated by the measured forces and chip morphology. The constitutive model and parameters for high strain rate conditions that are identical to those of cutting were obtained based on the SHPB tests and simulation.

关键词： constitutive model Ti-6Al-4V alloy SHPB test high strain rate machining

Preparation of Macroporous Poly (vinyl alcohol-co-triallyl isocyanurate) Beads Bearing Aminocarboxylic Acid as Functional Groups by Suspension Polymerization

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Chinese Chemical Letters 2003年第3期14卷 267-269页

作者： Hai Tao LI ke Yu shi 等 DepartmentofChemistry HunanNormalUniversityChangsha410081 TheStatekeyLaboratoryofFunctionalPolymerMaterialsforAdsorptionandSeparation InstituteofPolymerChemistrynankaiUniversity

Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.

关键词： Macroporous adsorption resin suspension polymerization poly (vinyl alcohol-co-triallyl isocyanurate) aminocarboxylic acid.

An intelligent control method for a large multi-parameter environmental simulation cabin

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Chinese Journal of Aeronautics 2013年第6期26卷 1360-1369页

作者： Li ke Liu Wangkai Wang jun Huang Yong Fundamental Science on Ergonomics and Environment Control Laboratory School of Aeronautic Science and Engineering Beihang University

The structure and characteristics of a large multi-parameter environmental simulation cabin are *** to the diffculties of control methods and the easily damaged characteristics,control systems for the large multi-parameter environmental simulation cabin are diffcult to be controlled quickly and accurately with a classical PID *** the dynamic state characteristics of the environmental simulation test chamber,a lumped parameter model of the control system is established to accurately control the multiple parameters of the environmental chamber and a fuzzy control algorithm combined with expert-PID decision is introduced into the temperature,pressure,and rotation speed control *** simulations and experimental results have shown that compared with classical PID control,this fuzzy-expert control method can decrease overshoot as well as enhance the capacity of anti-dynamic disturbance with *** can also resolve the contradiction between rapidity and small overshoot,and is suitable for application in a large multi-parameter environmental simulation cabin control system.

关键词： Environmental cabin Environmental testing Expert system Fuzzy control Mathematical models Turbines

LAMELLAR STRUCTURE IN LONG RANGE ORDERED PHASE δ′-TiN_(0.5)

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中国有色金属学会会刊：英文版 1997年第3期7卷 8-14页

作者： Yang, Caiying Du, jun shi, Likai General Research Inst for Nonferrous Metals Beijing China

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关键词： lamellar structure δ′ TiN 0.5 long range ordering transformation

Tracking dynamic evolution of catalytic active sites in photocatalytic CO2 reduction by in situ time-resolved spectroscopy

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Rare Metals 2020年第6期39卷 607-609页

作者： Guo-Zhu Chen ke-jun Chen jun-Wei Fu Min Liu School of Physics and Electronics State Key Laboratory of Powder MetallurgyCentral South UniversityChangsha 410083China

In situ time-resolved spectroscopy is an effective method to monitor the catalysis reaction in real time and reveal the catalytic mechanistic *** dynamic evolution of coordination and electronic structures of catalytic active sites during the CO2 reduction reaction is still a "black box," impeding the design of high-efficiency *** a recent report published in ***.,by multiple in situ time-resolved spectroscopy.

关键词： spectroscopy. resolved catalytic

Application of Artificial Bee Colony Algorithm to Maximum Likelihood DOA Estimation

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Journal of Bionic Engineering 2013年第1期10卷 100-109页

作者： Zhicheng Zhang jun Lin Yaowu shi College of Communication Engineering Jilin University Changchun 130012 P. R. China College of Instrumentation & Electrical Engineering Jilin University Changchun 130061 P. R. China

Maximum Likelihood （ML） method has an excellent performance for Direction-Of-Arrival （DOA） estimation, but a mul- tidimensional nonlinear solution search is required which complicates the computation and prevents the method from practical use. To reduce the high computational burden of ML method and make it more suitable to engineering applications, we apply the Artificial Bee Colony （ABC） algorithm to maximize the likelihood function for DOA estimation. As a recently proposed bio-inspired computing algorithm, ABC algorithm is originally used to optimize multivariable functions by imitating the be- havior of bee colony finding excellent nectar sources in the nature environment. It offers an excellent alternative to the con- ventional methods in ML-DOA estimation. The performance of ABC-based ML and other popular meta-heuristic-based ML methods for DOA estimation are compared for various scenarios of convergence, Signal-to-Noise Ratio （SNR）, and number of iterations. The computation loads of ABC-based ML and the conventional ML methods for DOA estimation are also investi- gated. Simulation results demonstrate that the proposed ABC based method is more efficient in computation and statistical performance than other ML-based DOA estimation methods.

关键词： DOA estimation maximum likelihood artificial bee colony algorithm bio-inspired computing

Prophylactic stenting for esophageal stricture prevention after endoscopic submucosal dissection

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World Journal of Gastroenterology 2017年第6期23卷 931-934页

作者： ke-Da shi Feng Ji Department of Gastroenterology First Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhou 310000Zhejiang ProvinceChina

Endoscopic submucosal dissection (ESD) of superficial esophageal cancer has been increasingly used as an alternative to surgery because it is minimally invasiveand has a high rate of en bloc resection. However, a high rate of esophageal stricture is observed after ESD for large lesions, which can dramatically decrease the patient's quality of life. Stricture prevention is necessary to allow for endoscopic therapy to expand. We, herein, review the most recent evidence and discuss the role of the metallic self-expandable stent and the biodegradable stent in esophageal stricture prevention. Limited studies suggested that prophylactic stenting could reduce the stricture rate without increasing the number of complications. In addition, the number of bougie dilation procedures was significantly lower with stent placement. Esophageal stenting is a promising option for post-ESD stricture prevention. However, current evidence is too preliminary to formulate practice standards. Future studies are needed to further validate the efficacy and safety of prophylactic stenting and determine the best strategy for stricture prevention. Stent migration is the most common complication. A new stent that has advantages of a low migration rate and minimal tissue reaction will need to be developed. Therefore, randomized controlled trials with long-term follow-up periods are required before prophylactic stenting could be considered a valid option to prevent post-ESD stricture.

关键词： Biodegradable stent Stricture prevention Esophageal stricture Metallic self-expandable stent Endoscopic submucosal dissection

Thermally-triggered grain boundary relaxation in a nanograined Ni-Mo-W alloy

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Nano Research 2023年第11期16卷 12800-12808页

作者： Dongsong Zeng Jiongxian Li Yinong shi Xiuyan Li ke Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

Conventionally,nanograined metals and alloys can be stabilized through segregating foreign elements at grain boundaries(GBs).Yet such an effect may be offset by formation of second phase at elevated *** this paper,by introducing minor W into a binary Ni-Mo alloy,we found precipitation of intermetallic phases was suppressed,enhancing thermal stability of the nanograined *** faceted GBs and a high-fraction ofΣ3 coincidence site lattice(CSL)boundaries illustrate that GB structures are relaxed by formation of copious annealing *** W reduces stacking fault energy of the solid solution and facilitates the thermally-triggered GB *** precipitation of the intermetallic phases may be attributed to depletion of solutes at relaxed GBs.

关键词： grain boundary relaxation nanograined ternary alloy thermal stability stacking fault energy

Correction of extreme hyperopia: artisan iris-fixated intraocular lens implantation for pseudophakia after clear lens extraction

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International Journal of Ophthalmology(English edition) 2011年第4期4卷 454-457页

作者： Wen Xu Pan-Pan Ye ke Yao Zhao-Chun Li Feng-Ying He jun-Ting shi and jun Liu Eye Center Second Affiliated Hospital Zhejiang University No.88 Jiefang Road Hangzhou 310009 Zhejiang Province China

A 22-year-old patient suffering from both-side extreme hyperopia with amblyopia was corrected with an Artisan iris-fixated intraocular lens (IOL) implantation followed to clear lens extraction (CLE) with posterior chamber (PC)-IOL implantation. The preoperative refraction values were +17.75DS -1.50DC × 168° for the right eye and +17.25DS -0.75DC × 8° for the left eye. The uncorrected visual acuity (UCVA) was 20/200 bilaterally and the spectacle-corrected visual acuity (BSCVA) was 20/50 bilaterally. One year after Artisan iris-fixated IOL implantation, bilateral BSCVA was 20/50 with a refraction of +1.25DS -0.75DC × 13° for the right eye and +1.50DS -1.00DC × 55° for the left eye. The outcomes of an Artisan iris-fixated IOL implantation followed to CLE with PC-IOL implantation were encouraging for the correction of extreme hyperopia. Long term follow-up examinations were necessary for further determination of the efficacy and safety of this combinational procedure.

关键词： hyperopia clear lens extraction iris-fixated intraocular lens