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Influence mechanism of silicon surface generation in ultraprecision turning
Zhang Shijun 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.4
A quantificational approach was proposed to analyze the discrepancy of monocrystalline silicon surface roughness along different crystal orientations in diamond turning on Statistical Product and Service Solutions software. This work aimed to understand how crystal orientation affects surface generation in the cutting behavior of monocrystalline silicon. In this study, the measured surface roughness data were first processed in advance to eliminate some adverse effects of outliers. The average values of surface roughness distributions were obtained. The surface roughness values of different measurement directions were compared, and the influences of crystal orientations on surface roughness were analyzed. Results indicate that the crystal orientation and the cutting parameters have much influence on machined surface roughness. Finding some special crystal orientations using Euclidean distance analysis with average analysis is effective. The vibration induced by crystallographic orientation is the main reason to make surface nonuniform roughness in single-point diamond turning. This finding is verified by analyzing the surface generation mechanism.
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ShiJun Chen,Qi Zhang,Biao He,SuRong Huang,Dou-Dou Hui 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.1
In order to meet the thermal performance analysis accuracy requirements of high density permanent magnet synchronous motor (PMSM), a method of multi physical domain coupling thermal analysis based on control circuit, electromagnetic and thermal is presented. The circuit, electromagnetic, fluid, temperature and other physical domain are integrated and the temperature rise calculation method that considers the harmonic loss on the frequency conversion control as well as the loss non-uniformly distributed and directly mapped to the temperature field is closer to the actual situation. The key is to obtain the motor parameters, the realization of the vector control circuit and the accurate calculation and mapping of the loss. Taking a 48 slots 8 poles high density PMSM as an example, the temperature rise distribution of the key components is simulated, and the experimental platform is built. The temperature of the key components of the prototype machine is tested, which is in agreement with the simulation results. The validity and accuracy of the multi physical domain coupling thermal analysis method are verified.
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Effects of Casein and Protein-free Diets on Endogenous Amino Acid Losses in Pigs
Zhang, Yongcheng,Li, Defa,Fan, Shijun,Piao, Xiangshu,Wang, Jitan,Han, In K. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.11
Quantification of endogenous amino acid loss at the terminal ileum is an essential means for calculation of the true amino acid digestibility of a feedstuff. Since nitrogen appeared in the determined diet or not could shift the results very much, also, none of digestibility markers could be recovered with 100% rate at the terminal ileum, the objectives of the present study were: (1) to determine endogenous amino acid losses when fed either a casein diet or a protein-free diet and (2) to examine the reliability of chromic oxide or acid insoluble ash in the protein-free diet. Six ileal-cannulated pigs ($65{\pm}1.85 kg$ BW) with a simple T-cannula in the terminal ileum were used in a replicated $3{\times}3$ Latin square designed trial, after allowed a 14 d recuperation period. Each test period ran for 12 days comprised of a 10 d adjustment period and a 2 d collection period. The endogenous AA losses of His, Ile, Lys, Cys, Thr, Val, Trp, Asp, Glu, and Ser from pigs fed the casein diet were significantly higher than those of the protein-free diet (p<0.05). No significant difference was found in the amount of endogenous amino acid loss when determined with the different markers in the protein-free diet (p>0.05). These data suggest that endogenous amino acid loss could be underestimated when a protein-free diet is used. A direct effect of dietary peptides on the endogenous amino acid loss was found when the casein diet was fed. Our results also indicate that acid insoluble ash can be used as an inert marker as an alternative to chromic oxide when measuring endogenous amino acid loss.
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Sai Zhang,Shijun Yue,Jiajia Li,Jian-Bin Zheng,Guojie Gao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11
Au nanoparticles anchored on core–shell α-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/α-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5 μM to 0.47 mM, a low detection limit of 0.17 μM (S/N = 3) and high sensitivity of 397.1 μA mM -1 cm -2. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.
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BMB Reports : Poly(ADP-ribose) protects vascular smooth muscle cells from oxidative DNA damage
( Chao Zhang ),( Tao Luo ),( Shijun Cui ),( Yongquan Gu ),( Chunjing Bian ),( Yibin Chen ),( Xiaochun Yu ),( Zhonggao Wang ) 생화학분자생물학회(구 한국생화학분자생물학회) 2015 BMB Reports Vol.48 No.6
Vascular smooth muscle cells (VSMCs) undergo death during atherosclerosis, a widespread cardiovascular disease. Recent studies suggest that oxidative damage occurs in VSMCs and induces atherosclerosis. Here, we analyzed oxidative damage repair in VSMCs and found that VSMCs are hypersensitive to oxidative damage. Further analysis showed that oxidative damage repair in VSMCs is suppressed by a low level of poly (ADP-ribosyl)ation (PARylation), a key post-translational modification in oxidative damage repair. The low level of PARylation is not caused by the lack of PARP-1, the major poly(ADP-ribose) polymerase activated by oxidative damage. Instead, the expression of poly(ADP-ribose) glycohydrolase, PARG, the enzyme hydrolyzing poly(ADP-ribose), is significantly higher in VSMCs than that in the control cells. Using PARG inhibitor to suppress PARG activity facilitates oxidative damage-induced PARylation as well as DNA damage repair. Thus, our study demonstrates a novel molecular mechanism for oxidative damage-induced VSMCs death. This study also identifies the use of PARG inhibitors as a potential treatment for atherosclerosis. [BMB Reports 2015; 48(6): 354-359]
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Chen, ShiJun,Zhang, Qi,He, Biao,Huang, SuRong,Hui, Dou-Dou The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.1
In order to meet the thermal performance analysis accuracy requirements of high density permanent magnet synchronous motor (PMSM), a method of multi physical domain coupling thermal analysis based on control circuit, electromagnetic and thermal is presented. The circuit, electromagnetic, fluid, temperature and other physical domain are integrated and the temperature rise calculation method that considers the harmonic loss on the frequency conversion control as well as the loss non-uniformly distributed and directly mapped to the temperature field is closer to the actual situation. The key is to obtain the motor parameters, the realization of the vector control circuit and the accurate calculation and mapping of the loss. Taking a 48 slots 8 poles high density PMSM as an example, the temperature rise distribution of the key components is simulated, and the experimental platform is built. The temperature of the key components of the prototype machine is tested, which is in agreement with the simulation results. The validity and accuracy of the multi physical domain coupling thermal analysis method are verified.
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He Du,Shijun Zhang,Yong Chen,Yunling Ke,Shi Chen,Xueyi Huang,Zhiqiang Li 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4
Juvenile hormone (JH) or juvenile hormone analog (JHA) can induce soldier formation in termites. However, different studies have yielded inconsistent results on the effects of JHA on soldier production in Coptotermes formosanus Shiraki. Using filter paper as the testing substrate, the effects of JH III, pyriproxyfen and methoprene on the intact filter paper left, worker mortality and presoldier formation were tested on six colonies. Our results showed that pyriproxyfen and methoprene were more repellent than JH III. No significant difference in toxicity was observed among methoprene, pyriproxyfen and JH III. JH III and pyriproxyfen did not cause workers to differentiate into presoldiers, but methoprene can induce formation of presoldiers. Colony response variability to methoprene was observed. The confirmation of the effects of JH/JHA on C. formosanus establishes the foundation for molecular studies of soldier differentiation in this species.
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Interfacial Reaction in (Mg-37.5Al)/(Mg-6.7Nd) Diffusion Couples
Jiahong Dai,Shijun Shen,Bin Jiang,Jianyue Zhang,Qingshan Yang,Zhongtao Jiang,Hanwu Dong,Fusheng Pan 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.1
The solid-state diffusion reaction between Mg-37.5Al and Mg-6.7Nd was studied in the 623-673 K temperature range. A solid-liquid contact method was employed to produce diffusion couples. The Al4Nd, Al11Nd3, Al3Nd and Al2Nd intermetallic compounds form in the diffusion reaction layers of the couples. The formation of intermetallic compounds in the diffusion reaction layers is rationalized using the Miedema model. The local average compositions through the diffusion reaction layer were determined, and used to construct a semi-quantitative diffusion path on the isothermal Mg-Al-Nd ternary phase diagram at 673 K. The growth constants of the entire diffusion reaction layers were determined as 8.91 (±0.94)×10 -14 m 2 /s, 1.39 (±0.15)×10 -13 m 2 /s and 1.93 (±0.38)×10 -13 m 2 /s at 623 K, 648 K and 673 K, respectively. The activation energy Q for the growth of the entire diffusion reaction layers was 54±4.6 kJ/mol.
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Xinyu Yang,Shijun Zhang,Junxiao Su,Sai Guo,Yakubu Ibrahim,Kai Zhang,Yonghao Tian,Lianlei Wang,Suomao Yuan,Xinyu Liu 대한척추신경외과학회 2024 Neurospine Vol.21 No.1
Objective: To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD). Methods: The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients’ clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated. Results: During a mean follow-up of 5.5 years (range, 5–7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio. Conclusion: Both TELD and MD provide generally satisfactory long-term clinical outcomes for patients with LDH. TELD can be used as a reliable alternative to MD with less surgical trauma. Modic type II changes, decreased preoperative intervertebral height, and a high body mass index are predictors of a poor prognosis. Objective: To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD). Methods: The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients’ clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated. Results: During a mean follow-up of 5.5 years (range, 5–7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio.
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