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Performance of Ion Plating TiAlN Coating on YG8
Huixia Zhang,Chonglin Liu,Long Lu,Haipeng Yan,류성기 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.2
Multi-arc ion plating technology and interactive deposition process are adopted to plate TiAlN hard film on the surface of YG8 cemented carbide cutting tools. Study the influences of the coating film parameters to surface appearance with orthogonal experiment method. Observe substrate samples, TiN transition layer and TiAlN coating film under the scanning electron microscope (SEM). Cutting test, friction and wearing test showed that the coated cutting tools are with more wearing resistance. The main wear mechanisms are adhesion, some accompanied by flake layer of disbanding. Coated cutting tools significantly reduces friction coefficient. By experimental design, the best process parameters are deposition temperature 100oC, substrate negative bias voltage 250 V, nitrogen partial pressure 0.6 Pa.
GOP Adaptation Coding of H.264/SVC Based on Precise Positions of Video Cuts
( Yunpeng Liu ),( Renfang Wang ),( Huixia Xu ),( Dechao Sun ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.7
Hierarchical B-frame coding was introduced into H.264/SVC to provide temporal scalability and improve coding performance. A content analysis-based adaptive group of picture structure (AGS) can further improve the coding efficiency, but damages the inter-frame correlation and temporal scalability of hierarchical B-frame to different degrees. In this paper, we propose a group of pictures (GOP) adaptation coding method based on the positions of video cuts. First, the cut positions are accurately detected by the combination of motion coherence (MC) and mutual information (MI); then the GOP is adaptively and proportionately set by the analysis of MC in one scene. In addition, we propose a binary tree algorithm to achieve the temporal scalability of any size of GOP. The results for test sequences and real videos show that the proposed method reduces the bit rate by up to about 15%, achieves a performance gain of about 0.28-1.67 dB over a fixed GOP, and has the advantages of better transmission resilience and video summaries.
Overexpression of OsVP1 and OsNHX1 Increases Tolerance to Drought and Salinity in Rice
Shiping Liu,Luqing Zheng,Yanhong Xue,Qian Zhang,Lu Wang,Huixia Shou 한국식물학회 2010 Journal of Plant Biology Vol.53 No.6
Drought and salinity are major abiotic stresses affecting rice production. To improve plant tolerance to salinity and drought, we overexpressed rice Na+/H+ exchangers (OsNHX1) and H+-pyrophosphatase in tonoplasts (OsVP1) in a japonica elite rice cultivar, Zhonghua 11. Compared with our wild-type control, transgenic plants overexpressing both genes incurred less damage when exposed to long-term treatment with 100 mM NaCl or water deprivation. Under high-saline conditions, the transformants accumulated less Na+ and malondialdehyde in the leaves,thereby allowing the plants to maintain a low level of leaf water potential and reduce stress-induced damage. Those transgenics also had higher photosynthetic activity during the stress period. Under those conditions, they also showed an increase in root biomass, which enabled more water uptake. These results suggest that OsVP1 and OsNHX1 improve the tolerance of rice crops against drought and salt by employing multiple strategies in addition to osmotic regulation.
Experimental and Numerical Research on the Laser Impact Welding of Ti/SS
Jiaxin Lu,Huixia Liu,Hao Jin,Feng Li,Xiaojun Wang,Xiao Wang 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.5
The welding of Ti/SS metal foil was realized by laser impact welding. The interface morphology and mechanical properties of welding specimens were studied by systematic experiments, and the experimental phenomena were revealed by smoothed particle hydrodynamics numerical simulation. Results indicated that the plastic deformation of the composite plate and the springback of the welding spot center were small under low laser pulse energy and enlarged under high laser pulse energy. Impinging jet, interface wave, and interface cracking were found at the micro-interface of the welding specimens. Increasing the laser pulse energy resulted in the transition of the interface waveform from straight to microwave and finally to wave primarily because of the change in interfacial impact pressure and effective plastic strain. Energy dispersive spectroscopy analysis showed that the trace element diff used at the welding interface, and no intermetallic compounds were formed. SPH simulation revealed that the thickness of the high-temperature layer was related to the thickness of the diffusion layer. As the distance between the test point and welding interface increased, the hardness decreased. The maximum tensile force of the welding specimens increased with laser pulse energy. The failure mode of the interface was welding spot edge fracture failure.
Hailiang Yang,Xiao Wang,Peng Ni,Zhewen Li,Huixia Liu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8
In order to use numerical simulation to reveal the formability of magnesium–lithium alloys and other light alloys under highstrain rate, it is crucial to construct a constitutive model and a forming limit diagram (FLD) of LA103Z alloy that was formedby laser shock at high strain rate. In this study, three different uniaxial tensile experiments on the ultralight alloy materialLA103Z magnesium alloy were conducted, the mechanical behavior of the material with sensitivity to high strain rate wasstudied, and a Johnson–Cook (JC) constitutive model sensitive to high strain rates and suitable for laser shock forming wasproposed. At the same time, the constitutive parameters and failure parameters of the modified JC model of LA103Z magnesiumalloy were obtained through three different uniaxial tensile experiments. On the basis of the relationship betweentensile loading and stress–strain of LA103Z magnesium alloy, the experiments demonstrated the precision of the modified JCconstitutive model. A modified constitutive model was then developed by using the user material subroutine VUMAT, andthen it was applied to ABAQUS. Finally, the formability of the material was simulated, and the FLD of LA103Z magnesiumalloy material in laser shock forming was predicted. This study provides guidance on the actual production and applicationof LA103Z magnesium alloys.