Optimization of Process Parameters of Hybrid Laser–Arc Welding onto 316L Using Ensemble of Metamodels

Zhou, Q.,Jiang, P.,Shao, X.,Gao, Z.,Cao, L.,Yue, C.,Li, X. Springer Verlag 2016 Metallurgical and materials transactions. B, Proce Vol.47 No.4

Strength and failure characteristics of the rock-coal combined body with single joint in coal

Yin, Da W.,Chen, Shao J.,Chen, Bing,Liu, Xing Q.,Ma, Hong F. Techno-Press 2018 Geomechanics & engineering Vol.15 No.5

Geological dynamic hazards during deep coal mining are caused by the failure of a composite system consisting of the rock and coal layers, whereas the joint in coal affects the stability of the composite system. In this paper, the compression test simulations for the rock-coal combined body with single joint in coal were conducted using $PFC^{2D}$ software and especially the effects of joint length and joint angle on strength and failure characteristics in a rock-coal combined body were analyzed. The joint length and joint angle exhibit a deterioration effect on the strength and affect the failure modes. The deterioration effect of joint length of L on the strength can be neglected with a tiny variation at ${\alpha}$ of $0^{\circ}$ or $90^{\circ}$ between the loading direction and joint direction. While, the deterioration effect of L on strength are relatively large at ${\alpha}$ between $30^{\circ}$ and $60^{\circ}$. And the peak stress and peak strain decrease with the increase of L. Additionally, the deterioration effect of ${\alpha}$ on the strength becomes larger with the increase of L. With the increase of ${\alpha}$, the peak stress and peak strain first decrease and then increase, presenting "V-shaped" curves. And the peak stress and peak strain at ${\alpha}$ of $45^{\circ}$ are the smallest. Moreover, the failure mainly occurs within the coal and no apparent failure is observed for rock. At ${\alpha}$ between $30^{\circ}$ and $60^{\circ}$, the secondary shear cracks generated in or close to the joint tips, cause the structural instability failure of the combined body. Therefore, their failure models present as a shear failure along partial joint plane direction and partially cutting across the coal body or a shear failure along the joint plane direction. However, at ${\alpha}$ of $60^{\circ}$ and L of 10 mm, the "V-shaped" shear cracks cutting across the coal body cause its final failure. While crack nucleations at ${\alpha}$ of $0^{\circ}$ or $90^{\circ}$ are randomly distributed in the coal, the failure mode shows a V-shaped shear failure cutting across the coal body.

Effect of Different Rates of Ethanol Additive on Fermentation Quality of Napiergrass (Pennisetum purpureum)

Zhang, Lei,Yu, C.Q.,Shimojo, M.,Shao, T. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.5

The effect of different rates of ethanol additive on fermentation quality of napiergrass (Pennisetum purpureum) and residual water soluble carbohydrate were studied in the experiment. The addition rate of ethanol was 0%, 1.5%, 2.5%, 3.5%, 4.5% on fresh weight of napiergrass. The laboratory silos were kept in the room, then were opened on 1, 3, 5, 7, 14, 30 days after ensiling and the changes of silage quality were analyzed, respectively. There was a fast and large reduction in pH from the 5th day of ensiling to below 4.2 except for the 4.5% treatment. After five days the pH of silage decreased slowly and the pH of the ethanol additions was lower than the control. Lactic acid content of ethanol treatments increased significantly (p<0.05) from the 5th day of ensiling, reaching the highest value on either the 7th day or 14th day. The ethanol additive inhibited the break down of silage protein and the ammonia nitrogen content of ethanol addition silage was significantly (p<0.05) lower than the control after 30 days of ensiling. Within the initial first day of ensiling the water soluble carbohydrate content declined quickly. The efficiency of water soluble carbohydrate usage was higher in silage with ethanol than in the control. The acetic acid of ethanol treatment was significantly (p<0.05) lower than control on first and 14th day, but there was no significant (p>0.05) difference among the ethanol addition silages. The volatile fatty acids content of silage increased gradually from the first day of ensiling and reached the peak on 14th day or 30th day and the content of ethanol addition treatment was significantly (p<0.05) lower than the control. The experimental results indicated that adding ethanol inhibited the use of protein and water soluble carbohydrate of aerobic bacteria and reduced the silage losses during the early stage of ensiling and thus supplied more fermentation substrate for lactic acid bacteria and improved the fermentation quality of napiergrass.

The Effect of Transformer Leakage Inductance on the Steady State Performance of Push-pull based Converter with Continuous Current

Qian Chen,Trillion Q. Zheng,Yan Li,Tiancong Shao 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.3

As a result of the advantages such as high efficiency, continuous current and high stability margin, push-pull converter with continuous current (PPCWCC) is competitive for battery discharge regulator (BDR) which plays an important role in power conditioning unit (PCU).Leakage inductance yields current spike in low-ripple current of PPCWCCs. The operating modes are added due to leakage inductance. Therefore the steady state performance is affected, which is embodied in the spike of low-ripple current. PPCWCCs which are suitable for BDR can be separated into three types by current spike characteristics. Three representative topologies IIs1, IIcb2 and Is3 are analyzed in order to investigate the factors on the magnitude and duration of spike. Equivalent current sampling method (ECSM) which eliminates the sampling time delay and achieves excellent dynamic performance is adopted to prevent the spike disturbance on current sampling. However, ECSM reduces the sampling accuracy and telemetry accuracy due to neglecting the spike. In this paper, ECSM used in PPCWCCs is summarized. The current sampling error is analyzed in quality and quantity, which provides the foundation for offsetting and enhancing the telemetry accuracy. Finally, current sampling error rate of three topologies is compared by experiment results, which verify the theoretical analysis.

Shear Thickening Polishing of Black Lithium Tantalite Substrate

B. H. Lyu,Q. Shao,W. Hang,S. H. Chen,Q. K. He,J. L. Yuan 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.9

To achieve high efficiency in the polishing process to obtain a high surface quality of black LT substrate (a kind of soft brittle material), shear thickening polishing (STP), which is a “gentle” finishing process developed in recent years, was employed in this study. The influence of three key parameters in the STP process including polishing speed, diamond abrasive size and diamond abrasive concentration were analyzed. To investigate the potential mechanical effect of the nanometre abrasive, nano-SiO 2 abrasive particles were added in the slurry, and the concentration of SiO 2 abrasive was also taken as a factor. Taguchi method was utilized to evaluate the influence of the four factors and optimize the polishing conditions. The surface roughness (Ra/Rz) was used as the evaluation index, and the optimized polishing conditions were verified through experiments. Diamond abrasive size has the most significant effect on Ra/Rz, followed by diamond abrasive concentration and then SiO 2 concentration, as the polishing speed has been selected and limited in a small variation rang according to the previous study. Based on the S/N average response analysis, the surface quality is the best under the conditions with 8000# diamond abrasive, 5 wt% diamond abrasive concentration, 90 rpm polishing speed and 10 wt% SiO 2 concentration. After 4 min polishing, the surface roughness Ra/Rz is reduced rapidly from 200.5/1374.6 to 4.2/22.1 nm without embedded abrasive particles on the surface of the black LT substrate. It also shows that the mechanical effect plays a dominant role in the material removal. A certain amount (10 wt% in this study) of nano-SiO 2 can reduce friction between solid colloidal and workpiece, and helps to improve surface quality.

The Effect of Transformer Leakage Inductance on the Steady State Performance of Push-pull based Converter with Continuous Current

Chen, Qian,Zheng, Trillion Q.,Li, Yan,Shao, Tiancong The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.3

As a result of the advantages such as high efficiency, continuous current and high stability margin, push-pull converter with continuous current (PPCWCC) is competitive for battery discharge regulator (BDR) which plays an important role in power conditioning unit (PCU). Leakage inductance yields current spike in low-ripple current of PPCWCCs. The operating modes are added due to leakage inductance. Therefore the steady state performance is affected, which is embodied in the spike of low-ripple current. PPCWCCs which are suitable for BDR can be separated into three types by current spike characteristics. Three representative topologies IIs1, IIcb2 and Is3 are analyzed in order to investigate the factors on the magnitude and duration of spike. Equivalent current sampling method (ECSM) which eliminates the sampling time delay and achieves excellent dynamic performance is adopted to prevent the spike disturbance on current sampling. However, ECSM reduces the sampling accuracy and telemetry accuracy due to neglecting the spike. In this paper, ECSM used in PPCWCCs is summarized. The current sampling error is analyzed in quality and quantity, which provides the foundation for offsetting and enhancing the telemetry accuracy. Finally, current sampling error rate of three topologies is compared by experiment results, which verify the theoretical analysis.

FACTORS CONTROLLING THE STRONGEST SIZES IN THE INVERSE HALL-PETCH RELATIONSHIP

YONG PAN,ZHAO FENG ZHOU,SHAO-YUN FU,YANGUANG NIE,CHANG Q SUN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.3

Incorporating the bond-order-length-strength correlation mechanism [Sun CQ, Prog Solid State Chem 35, 1 (2007)] and Born’s criterion for melting [J. Chem. Phys. 7, 591 (1939)] into the conventional Hall-Petch relationship has turned out an analytical expression for the size and temperature dependence of the mechanical strength of nanograins, known as the inverse Hall-Petch relationship (IHPR). Reproduction of the measured IHPR of Ni, NiP and TiO2 nanocrystals revealed that: (i) the competition between the size-induced energy-density gain and atomic cohesive energy loss in the surface skins of nanograins originate the IHPR; (ii) the competition between the activation and inhibition of atomic dislocations motion activate the entire IHPR behavior; (iii) the bond nature involved and the T/Tm ratio between the temperature of operating and the temperature of melting dictate the measured strongest sizes of a given specimen; (iv) a quasimolten phase presenting before melting determines the size-induced softening and the superplasticity of nanostructures.

Responsiveness to reduced dosage of rituximab in Chinese patients with neuromyelitis optica

Yang, C.-S.,Yang, L.,Li, T.,Zhang, D.-Q.,Jin, W.-N.,Li, M.-S.,Su, N.,Zhangning, N.,Liu, Q.,Shao, Z.-H.,Yu, C.,Shi, F.-D. Ovid Technologies (Wolters Kluwer) - American Acad 2013 Neurology Vol.81 No.8

Giant electrocaloric effect in BaZr_0.2Ti_0.8O₃ thick film

Ye, Hui-Jian,Qian, Xiao-Shi,Jeong, Dae-Yong,Zhang, Shujun,Zhou, Yue,Shao, Wen-Zhu,Zhen, Liang,Zhang, Q. M. American Institute of Physics 2014 Applied Physics Letters Vol.105 No.15