Study on the Fracture Properties of the PMMA Structure for the JUNO Central Detector

Zongyi Wang,Yuanqing Wang,Xinxi Du,Tianxiong Zhang,Yuekun Heng 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.6

Polymethyl methacrylate (PMMA) is increasingly used in building structures nowadays. PMMA materials utilized in structures have different fracture property compared with those used in aircrafts or biomedical equipment. Single-edge-notch bending (SENB) tests were firstly carried out at various temperatures (-40°C, -20°C, 0°C, 20°C, and 40°C) to determine the KIC values of base PMMA materials and connected areas. The crack-resisting capacity of PMMA plate is subsequently studied. The fracture property of the PMMA joint for the Jiangmen Underground Neutrino Observatory (JUNO) central detector is investigated. The results show that base PMMA material has higher KIC values than connected area. The KIC of base PMMA material is lowest at 20°C and highest at -20°C, while that of connected area is lowest at 40°C and highest at -40°C. For the PMMA joint of the JUNO detector, the cracks perpendicular to the X axis are more disadvantageous than those perpendicular to the Z axis. The stress intensity factors (SIFs) at the crack front of the embedded crack decrease with the increase of embedded depth. Due to the presence of two parallel surface or embedded cracks, the SIFs at the crack front decrease.

Attitude Control Design for Hypersonic Reentry Vehicles Subject to Control Direction Reversal via Sliding Mode Approach

Yixin Ding,Zongyi Guo,Yonglin Han,Jiaqi Wang,Jianguo Guo,Zequn Liu,Jinlong Zhao 한국항공우주학회 2024 International Journal of Aeronautical and Space Sc Vol.25 No.2

This paper investigates the control direction reversal issue for the attitude control design for hypersonic reentry vehicles, and proposes a novel sliding mode control law which addresses the control direction switching and strong robustness requirement simultaneously. Firstly, the disturbance observer is introduced to estimate the unmatched uncertainties in the attitude model of hypersonic reentry vehicles, and then a periodic function-involved sliding mode control is presented and the bounded stability of the closed-loop system is guaranteed via Lyapunov stability theory. The merits of the proposed method lie in that the closed-loop system is stable even under the unknown control direction reversal, and the unmatched uncertainties can be addressed by the disturbance observer. Finally, the simulation verifies the effectiveness and superiority of the proposed control.

Dynamic performance reliability analysis of rolling linear guide under parameter uncertainty

Jian Li,Yan Ran,Hongwei Wang,Guangquan Huang,Zongyi Mu,Genbao Zhang 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

This paper presents a dynamic reliability analysis method of rolling linear guide considering the uncertainty of geometric parameters. A three degree of freedom (DOF) dynamic motion model of rolling linear guide that considers the complexity of the actual load is established. In order to improve the accuracy of reliability evaluation, interval model is used to express the uncertainty of geometric parameters. The reliability range of dynamic response is determined according to the accuracy grade of rolling linear guide. The interval reliability calculation method is used to analyze and calculate the horizontal and vertical dynamic reliability of rolling linear guide. Then, the comprehensive dynamic reliability of rolling linear guide is obtained. Finally, the dynamic reliability of the SHS-45R rolling linear guide is analyzed by using the reliability evaluation method described in this paper. And the validity and accuracy of the result is demonstrated by comparing with the Monte Carlo simulation.

The Effect of Soybean Galactooligosaccharides on Nutrient and Energy Digestibility and Digesta Transit Time in Weanling Piglets

Zhang, Liying,Li, Defa,Qiao, Shiyan,Wang, Jituan,Bai, Lu,Wang, Zongyi,Han, In K. Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.11

Eight $12.4{\pm}0.6kg$ initial body weight crossbred barrows were used to determine the effect of soybean galactooligosaccharides on nutrient and energy digestibility, and digesta transit time. Four dietary treatments were utilized in this trial. Treatment one was a corn-soybean meal based diet (SBM) containing raffinose and stachyose at the levels of 0.16% and 0.75%, respectively. Treatment two (control) was a corn-HP300 (soybean concentrate protein) diet. In treatments three and four, 1.1% and 2.2% commercial stachyose was added to the control diet to provide total dietary stachyose at the levels of 1% and 2%, respectively. The soybean galactooligosaccharides (raffinose + stachyose) level in treatment one was slightly lower compared to that in treatment three. Three collection periods were run with two pigs for each treatment/period. There was a 4 d adjustment period followed by a 3 d collection period. The results showed that the nitrogen retention (86.79%) of pigs fed treatment two diet was higher than that of pigs fed treatment one by 5.2% (p<0.05). The nitrogen retention of treatment three was intermediate 83.09%. The apparent fecal digestibility of all amino acids in treatment two was numerically highest, followed by treatments three and four. However, there were no significant difference among groups (p>0.05). The dry matter (DM), organic matter (OM), crude protein (CP), and crude fiber (CF) digestibility numerically decreased as the soybean galactooligosaccharides level increased, but were not significantly different (p>0.05). Chromium content in feces (from the inclusion of 0.3% chromic oxide in the diets) differed among treatments (p<0.05) at 15 h, 18 h, and 21 h after eating. This showed that the digesta transit time was differed significantly among treatments. Treatment four was the shortest, followed by treatment three, SBM and control. The results demonstrated that in the absence of antinutritional factors and soybean antigen protein, inclusion of 1% and 2% stachyose in corn-HP300 diet has no significant effect on the digestibility of DM, OM, CP, CF and amino acids. When the soybean galactooligosaccharide level in diet one and diet three were adjusted to be almost the same, antinutritional factors such as trypsin inhibitor and soybean antigen protein could decrease the nutrient digestibility and nitrogen retention rate of diet. High levels of soybean galactooligosaccharides shortened the digesta transit time in the intestinal tract. This trial suggested that the total level of soybean galactooligosaccharides (stachyose+raffinose) in the weanling piglet diet is better not to exceed 1% when common soybean meal is used as main protein source.

Growth Performance and Post-Weaning Diarrhea in Piglets Fed a Diet Supplemented with Probiotic Complexes

( Xuhong Lu ),( Ming Zhang ),( Liang Zhao ),( Keshan Ge ),( Zongyi Wang ),( Luo Jun ),( Fazheng Ren ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.11

Weaning stress can affect the growth performance and intestinal health of piglets. Dietary alternatives to antibiotics, such as dietary probiotics, especially those containing multiple microbial species, are a preventive strategy for effectively controlling post-weaning diarrhea. In this study, we investigated forty-eight crossbred piglets in three treatment groups for 21 days: the control and experimental groups were supplemented with Enterococcus faecium DSM 7134, Bacillus subtilis AS1.836 plus Saccharomyces cerevisiae ATCC 28338 (EBS) or Lactobacillus paracasei L9 CGMCC No. 9800 (EBL). On day 21, weaned piglets supplemented with two kinds of probiotic complexes showed increased growth performance and significantly reduced postweaning diarrhea (p < 0.05). The EBS treatment increased acetic acid and propionic acid in the feces (p < 0.05), and the EBL treatment increased fecal acetic acid, propionic acid, butyrate and valerate (p < 0.05). Moreover, the fecal microbiota of the piglets changed markedly in EBL treatment. The addition of EBS and EBL may have similar effects on the prevention of diarrhea by improving the intestinal morphology and regulating the microbiota during the weaning period.