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Influence of hydrogen on incipient plasticity in CoCrFeMnNi high-entropy alloy
Yang, Guanghui,Zhao, Yakai,Lee, Dong-Hyun,Park, Jeong-Min,Seok, Moo-Young,Suh, Jin-Yoo,Ramamurty, Upadrasta,Jang, Jae-il Elsevier 2019 Scripta materialia Vol.161 No.-
<P><B>Abstract</B></P> <P>The influence of hydrogen on the onset of plastic deformation in a CoCrFeMnNi high-entropy alloy (HEA) was examined through the analysis of the load at which first pop-in during spherical nanoindentation experiments occurs on hydrogen-charged and subsequently aged specimens. Results reveal that the dissolved hydrogen lowers the plastic flow resistance, indicated by the shear yield strength, <I>τ</I> <SUB>y</SUB>, by modifying defect formation energies. Aging, subsequent to charging, leads to recovery of <I>τ</I> <SUB>y</SUB>, but only partially. The results are discussed in terms of the vacancy-mediated dislocation nucleation, which is supported by the estimated activation volume for deformation.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Active control of amplitude and phase of high-power RF systems in EAST ICRF heating experiments
Zhu Guanghui,Liu Lunan,Mao Yuzhou,Zhang Xinjun,Guo Yaoyao,Ai Lin,Jiang Runhao,Qin Chengming,Zhang Wei,Yang Hua,Yuan Shuai,Wang Lei,Ju Songqing,Wang Yongsheng,Sun Xuan,Yang Zhida,Wang Jinxin,Cheng Yan 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2
The EAST ICRF system operating space has been extended in power and phase control with a low-level RF system for the new double-strap antenna. Then the multi-step power and periodic phase scanning experiment were conducted in L-mode plasma, respectively. In the power scanning experiment, the stored energy, radiation power, plasma impedance and the antenna's temperature all have positive responses during the short ramp-ups of PL;ICRF. The core ion temperature increased from 1 keV to 1.5 keV and the core heating area expanded from jZj 5 cmto jZj 10 cm during the injection of ICRF waves. In the phasing scanning experiment, in addition to the same conclusions as the previous relatively phasing scanning experiment, the superposition effect of the fluctuation of stored energy, radiation power and neutron yield caused by phasing change with dual antenna, resulting in the amplitude and phase shift, was also observed. The active control of RF output facilitates the precise control of plasma profiles and greatly benefits future experimental exploration.
Dissolution of synthetic U-DBP and corrosion of stainless steel by dissolution schemes
Wang Guanghui,Li Yaorui,He Mingjian,Zhang Meng,Gao Yang,He Hui,Jiao Caishan 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.5
In spent fuel reprocessing, UO2(DBP)2 (U-DBP) can be deposited in stainless steel equipment. U-DBP must be removed by dissolution and the process must not cause corrosion to stainless steel. This study was conducted to find the best scheme for dissolution. U-DBP was manufactured by the titrimetric sedimentation method. The effects of different factors on the dissolution of U-DBP were investigated. For example, solid-liquid ratio, hydrazine carbonate solutions with different mass components, mixed solutions containing different concentrations of H2O2, and different carbonates. The results indicated that U-DBP does not have a regular crystal morphology. With the increase of the solid-liquid ratio and the mass fraction of hydrazine carbonate, the concentration of U(VI) at the dissolution equilibrium increases gradually. The addition of H2O2 has a great promotion effect on the dissolution. However, when the concentration of H2O2 is greater than 0.5 M, the dissolution solution may have an erosive effect on the stainless steel. (NH4)2CO3 can increase the dissolution capacity of dissolved U-DBP, but it may also accelerate the corrosion of stainless steel.
Jia Huili,Yang Guanghui,Yang Jiaqiang 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1
The multiphase induction motor (MIM) suff ers the problems of unsmoothness and slow dynamic response during the process of electronic pole-changing. To solve this issue, a cosine-response strategy based on proportional resonance (PR) current controller is proposed. Firstly, a current switching strategy with cosine-response is designed, which makes the MIM work more smoothly while switching between two planes. Then, the PR controller based on static coordinate system is adopted to replace the traditional proportional integral current loop controller, which realizes the zero steady-state error tracking of the current and improves MIM’s dynamic response. Experiments on a fi ve-phase induction motor verify that the proposed strategy can reduce the fl uctuations of the torque, speed, and total harmonic distortion of phase current. Besides, it can improve the dynamic response of the torque and speed when the pole-changing is switched.
Teng Ma,Tiwu Peng,Yang Lin,Mindi Zhang,Guanghui Ren 대한치과보철학회 2023 The Journal of Advanced Prosthodontics Vol.15 No.3
PURPOSE. The objective of this study was to investigate how internal structures influence the overall and marginal accuracy of full arch preparations fabricated through additive manufacturing in different printing systems. MATERIALS AND METHODS. A full-arch preparation digital model was set up with three internal designs, including solid, hollow, and grid. These were printed using three different resin printers with nine models in each group. After scanning, each data was imported into the 3D data processing software together with the master cast, aligned and trimmed, and then put into the 3D data analysis software again to compare the overall and marginal deviation whose results are expressed using root mean square values and color maps. To evaluate the trueness of the resin model, the test data and reference data were compared, and the precision was evaluated by comparing the test data sets. Color maps were observed for qualitative analysis. Data were statistically analyzed by one-way analysis of variance and Bonferroni method was used for post hoc comparison (α = .05). RESULTS. The influence of different internal structures on the accuracy of 3D printed resin models varied significantly (P < .05). Solid and grid models showed better accuracy, while the hollow model exhibited poor accuracy. The color maps show that the resin models have a tendency to shrink inwards. CONCLUSION. The internal structure design influences the accuracy of the 3D printing model, and the effect varies in different printing systems. Irrespective of the kind of printing system, the printing accuracy of hollow model was observed to be worse than those of solid and grid models.
Chunteng Li,Yuzhong Jiang,Guanghui Yang,Fangjun Liu 한국자기학회 2018 Journal of Magnetics Vol.23 No.2
In order to design a kind of high-sensitive, narrow-band and portable search coil magnetometer, based on the principle of magnetic measuring, an equivalent model of search coil magnetometer with parallel matched capacitor is established. The formula of the induced coil is derived, low-noise integrated operational amplifier is designed and made as the preamplifier circuit of search coil magnetometer. The parameters of the inductive coil based on multi-parameter joint optimization are obtained under consideration of the sensitivity, bandwidth, weight and volume of the inductive coil simultaneously. The search coil magnetometer test is completed in the electromagnetic shielding room. And the result shows that the sensitivity of the designed search coil magnetometer is 40 fT√Hz @80 Hz, under the precondition of guaranteeing the weight, volume and bandwidth, which is basically the same as that of the simulation.
Regeneration of PAC used for reverse osmosis concentrate treatment by wet oxidation
Yanlin Yuan,Ping Gu,Yanling Yang,Guanghui Zhang 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.34 No.-
The wet oxidation (WO) regeneration of powdered activated carbon (PAC) used for reverse osmosisconcentrate (ROC) treatment was studied. The exhausted PAC was regenerated at different temperaturesand times. The experimental results indicated that the optimum regeneration condition could beachieved at a temperature of 200 8C for 60 min. The mass of carbon in the solid, gas and liquid phasesbefore and after the PAC regeneration was balanced in different regeneration conditions. A molecularweight (MW) distribution of organic matter (OM) in the effluent treated by the PAC regenerated atoptimum conditions was performed.
Nano-graining a particle-strengthened high-entropy alloy
Lee, Dong-Hyun,Park, Jeong-Min,Yang, Guanghui,He, Junyang,Lu, Zhaoping,Suh, Jin-Yoo,Kawasaki, Megumi,Ramamurty, Upadrasta,Jang, Jae-il Elsevier 2019 Scripta materialia Vol.163 No.-
<P><B>Abstract</B></P> <P>The possibility of further enhancing the strength of a (CoCrFeNi)<SUB>94</SUB>Ti<SUB>2</SUB>Al<SUB>4</SUB> high-entropy alloy (HEA), which is already strengthened by Ni<SUB>3</SUB>(Ti,Al) second-phase particles, by grain refinement through high-pressure torsion (HPT) is examined. Concomitant with nanograin formation, HPT was found to induce particle dissolution and structural transformation of the remnant particles. Nanoindentation experiments of nanocrystalline HEA, with and without particles in the pre-HPT microstructure, suggests that grain boundary strengthening is the dominant strengthening mechanism.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Lee, Dong-Hyun,Choi, In-Chul,Yang, Guanghui,Lu, Zhaoping,Kawasaki, Megumi,Ramamurty, Upadrasta,Schwaiger, Ruth,Jang, Jae-il Elsevier 2018 Scripta materialia Vol.156 No.-
<P><B>Abstract</B></P> <P>Nanoindentation experiments in the temperature (<I>T</I>) range of 298 and 573 K were performed to determine the activation energy (<I>Q</I>) for the plastic flow in a nanocrystalline CoCrFeMnNi high-entropy alloy, which was synthesized using high-pressure torsion. A marked increase in <I>Q</I> from ~0.5 to ~1.8 eV was observed when <I>T</I> is increased from 473 to 523 K, which correspond to ~0.3 and ~0.34 <I>T</I> <SUB>m</SUB> (<I>T</I> <SUB>m</SUB>: melting temperature), respectively. Detailed analysis reveals that this transition is associated with the additional activation of the grain boundary diffusion mechanism in enhancing plasticity.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
High-Temperature Activation of Zeolite-Loaded Fiber Sorbents
Sujan, Achintya R.,Koh, Dong-Yeun,Zhu, Guanghui,Babu, Vinod P.,Stephenson, Neil,Rosinski, Andrew,Du, Hai,Luo, Yang,Koros, William J.,Lively, Ryan P. American Chemical Society 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.34
<P>Here, we describe the formation of zeolite LiX fiber sorbents and postfabrication activation at temperatures of 350-400 °C for use in air separations. Two polymers were considered as the support matrices for the LiX zeolites: Torlon (polyamide-imide) and Matrimid (polyimide). Torlon-based fiber sorbents exhibit approximately 4% mass loss during the high-temperature (370 °C) activation required for zeolites, which is close to the glass transition temperature of these polymers. This mass loss is accompanied by the formation of pyrolytic side products that ultimately resulted in contamination of the LiX crystals and a 73% reduction in N<SUB>2</SUB> sorption capacity at ambient temperatures. In contrast, Matrimid was found to be suitable for fiber sorbent synthesis with only 10-15% reduction in N<SUB>2</SUB> sorption capacity observed upon the thermal activation. A LiX loading of 73% in monolithic fibers (i.e., no bore) by weight was achievable. Experimental breakthrough tests at 25 °C were conducted on an activated fiber module consisting of densely packed LiX-Matrimid fiber sorbents and operated over a range of adsorption pressures (1-3.5 bar) that are often used in an actual pressure swing adsorption (PSA) process for air separation.</P> [FIG OMISSION]</BR>