Strain path effects on the microstructure evolution and mechanical properties of Zr702

Cao, W.Q.,Yu, S.H.,Chun, Y.B.,Yoo, Y.C.,Lee, C.M.,Shin, D.H.,Hwang, S.K. Elsevier 2005 Materials science & engineering. properties, micro Vol.395 No.1

<P><B>Abstract</B></P><P>A commercial-purity Zr702 was grain-refined from 20μm to 0.2–0.5μm by equal channel angular pressing. Grain refinement was most evident in the first pass but was insignificant during the subsequent passes. Two microstructural characteristics evolved: a lamellar structure and an equiaxed subgrain structure during the route A pressing and the route B<SUB>C</SUB> pressing, respectively. Due to the rotation of specimen in between passes, two sets of geometrically necessary boundaries were formed during the route B<SUB>C</SUB> pressing. The mechanism of grain refinement during the route A pressing was evolution of high-angle geometrically necessary boundaries from the low-angled ones, while that during the route B<SUB>C</SUB> pressing was decomposition and rearrangement of pre-existing boundaries. The yield stress of severely deformed specimens increased with the reducing grain size according to a Hall–Petch relationship.</P>

A novel evidence theory model and combination rule for reliability estimation of structures

Y.R. Tao,Q. Wang,L. Cao,S.Y. Duan,Z.H.H. Huang,G.Q. Cheng 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.4

Due to the discontinuous nature of uncertainty quantification in conventional evidence theory(ET), the computational cost of reliability analysis based on ET model is very high. A novel ET model based on fuzzy distribution and the corresponding combination rule to synthesize the judgments of experts are put forward in this paper. The intersection and union of membership functions are defined as belief and plausible membership function respectively, and the Murfhy’s average combination rule is adopted to combine the basic probability assignment for focal elements. Then the combined membership functions are transformed to the equivalent probability density function by a normalizing factor. Finally, a reliability analysis procedure for structures with the mixture of epistemic and aleatory uncertainties is presented, in which the equivalent normalization method is adopted to solve the upper and lower bound of reliability. The effectiveness of the procedure is demonstrated by a numerical example and an engineering example. The results also show that the reliability interval calculated by the suggested method is almost identical to that solved by conventional method. Moreover, the results indicate that the computational cost of the suggested procedure is much less than that of conventional method. The suggested ET model provides a new way to flexibly represent epistemic uncertainty, and provides an efficiency method to estimate the reliability of structures with the mixture of epistemic and aleatory uncertainties.

Effects of Living Mulch on Soil Water Content of a Rain-fed Apple Orchard

Q. Cao,Z. K. Wang,X. M. Zhang,Y. Y. Shen 한국초지조사료학회 2016 한국초지조사료학회 학술대회논문집 Vol.2016 No.08

Studies on Genetic Variation of Different Chinese Duck Populations with Random Amplified Polymorphic DNA Analysis

Su, Y.,Liu, C.W.,Liu, L.,Ye, C.H.,Cao, W.Q.,Huang, Y.Q.,Zheng, J.,Cai, D.Y.,Olowofeso, O. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.4

The genetic polymorphism and relationships of Muscovy, Cherry Valley Meat ducks, Partridge ducks and their crossbreds $F_1$ and $F_2$, respectively, were studied using a random amplified polymorphic DNA (RAPD) technique. The results showed that RAPD markers were effective for the analysis of genetic relationships among ducks. Amplification with 20-primers gave 760 reproducible amplified fragments. The percentage of polymorphic marker band was 74.70%, which indicates that the RAPD technique had higher efficiency of polymorphism detection and sensitivity in studying the genetic variations among ducks and showed that the genetic polymorphism was abundant between two species of duck populations. The average index of genetic distance in hybrid $F_2$ was 0.2341 and higher than that of its parents, which indicates that the genetic diversity was improved by crossbreeding with Muscovy.

Evaluation of Coarsely Ground Wheat as a Replacement for Ground Corn in the Diets of Lactating Dairy Cows

Guo, Y.Q.,Zou, Y.,Cao, Z.J.,Xu, X.F.,Yang, Z.S.,Li, Shengli Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.7

Eight multiparous Holstein cows ($569{\pm}47$ kg of BW; $84{\pm}17$ DIM) were used to evaluate the effects of different levels of coarsely ground wheat (CGW) as replacements for ground corn (GC) in diets on feed intake and digestion, ruminal fermentation, lactation performance, and plasma metabolites profiles in dairy cows. The cows were settled in a replicated $4{\times}4$ Latin square design with 3-wk treatment periods; four cows in one of the replicates were fitted with rumen cannulas. The four diets contained 0, 9.6, 19.2, and 28.8% CGW and 27.9, 19.2, 9.6, and 0% GC on dry matter (DM) basis, respectively. Increasing dietary levels of CGW, daily DM intake tended to increase quadratically (p = 0.07); however, apparent digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were significantly decreased (p<0.01) in cows fed the 28.8% CGW diets. Ruminal pH remained in the normal physiological range for all dietary treatments at all times, except for the 28.8% CGW diets at 6 h after feeding; moreover, increasing dietary levels of CGW, the daily mean ruminal pH decreased linearly (p = 0.01). Increasing the dietary levels of CGW resulted in a linear increase in ruminal propionate (p<0.01) and ammonia nitrogen ($NH_3$-N) (p = 0.06) concentration, while ruminal acetate: propionate decreased linearly (p = 0.03) in cows fed the 28.8% CGW diets. Milk production was not affected by diets; however, percentage and yield of milk fat decreased linearly (p = 0.02) when the level of CGW was increased. With increasing levels of dietary CGW, concentrations of plasma beta-hydroxybutyric acid (BHBA) (p = 0.07) and cholesterol (p<0.01) decreased linearly, whereas plasma glucose (p = 0.08), insulin (p = 0.02) and urea nitrogen (p = 0.02) increased linearly at 6 h after the morning feeding. Our results indicate that CGW is a suitable substitute for GC in the diets of dairy cows and that it may be included up to a level of 19.2% of DM without adverse effects on feed intake and digestion, ruminal fermentation, lactation performance, and plasma metabolites if the cows are fed fiber-sufficient diets.

Effect of Genistein on Antioxidative Defence System and Membrane Fluidity in Chick Skeletal Muscle Cells

Jiang, Z.Y.,Jiang, S.Q.,Lin, Y.C.,Ma, X.Y.,Xi, P.B.,Cao, T.,Wang, X.Q. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.8

This study was conducted to investigate the protective effect of genistein on the antioxidative defence system and membrane fluidity in chick skeletal muscle cells after supplementation with 0, 20, 40, and $80{\mu}mol/L$ genistein in $50{\mu}mol/L$ $FeSO_4/H_2O_2$ treated cells for 24 h. Genistein supplementation recovered the decreased activity of total superoxide dismutase induced by $FeSO_4/H_2O_2$, significantly increased glutathione peroxidase activity (p<0.05) and decreased malondialdehyde production (p<0.05). The treatment of 80 mol/L genistein in $FeSO_4/H_2O_2$ treated cells decreased the secretion of creatine kinase (p<0.05). Fluorescence polarization values and microviscosities observed with $FeSO_4/H_2O_2$ treated cells were significantly higher than those observed with no $FeSO_4/H_2O_2$ treated cells. The addition of $80{\mu}mol/L$ genistein improved the increased fluorescence polarization value (p<0.05) caused by $FeSO_4/H_2O_2$ treatment. The microviscosity value was significantly decreased by adding genistein (p<0.05). In conclusion, genistein protected skeletal muscle cells from oxidative damage by improving antioxidative status and membrane fluidity.

Direct observation of asymmetric domain wall motion in a ferroelectric capacitor

Lee, J.K.,Shin, G.Y.,Song, K.,Choi, W.S.,Shin, Y.A.,Park, S.Y.,Britson, J.,Cao, Y.,Chen, L.Q.,Lee, H.N.,Oh, S.H. Elsevier Science 2013 ACTA MATERIALIA Vol.61 No.18

We report in situ transmission electron microscopy observations of the 180<SUP>o</SUP> polarization switching process of a PbZr<SUB>0.2</SUB>Ti<SUB>0.8</SUB>O<SUB>3</SUB> (PZT) capacitor. The preferential, but asymmetric, nucleation and forward growth of switched c-domains were observed at the PZT/electrode interfaces, arising due to the built-in electric field induced at each interface. The subsequent sideways growth of the switched domains was inhibited by the depolarization field due to the imperfect charge compensation at the counter-electrode and also at the boundaries with preexisting a-domains, which contributed further to the asymmetric switching behavior. It was found that the preexisting a-domains split into fine a- and c-domains constituting a 90<SUP>o</SUP> stripe domain pattern during the 180<SUP>o</SUP> polarization switching process, revealing that these domains also actively participated in the out-of-plane polarization switching. The real-time observations uncovered the origin of the switching asymmetry and further clarified the importance of charged domain walls and the interfaces with electrodes in the ferroelectric switching processes.

China Spallation Neutron Source: Accelerator Design Iterations and R&D Status

J. Wei,C.-D. Deng,C.-H. Wang,C.-T. Shi,H. Sun,H.-F. Ouyang,H.-M. Qu,H.-Y. Dong,J. Li,J. Zhang,J.-S. Cao,J.-Y. Tang,L. Dong,L.-L. Wang,Q. Qin,Q.-B. Wang,S. Wang,S.-N. Fu,S.-X Fang,T. -G. Xu,W. Kang,Y.- 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I

The China Spallation Neutron Source (CSNS) is a high-power, accelerator-based project currently under preparation. The accelerator complex consists of an H$^-$ ion source, an H$^-$ linac, a rapid-cycling proton synchrotron, and the transport lines. During the past year, the design of most accelerator systems went through major iterations, and initial research and developments was started on the prototyping of several key components.

Safety Analysis of Structures with Probability and Evidence Theory

Y. R. Tao,L. Cao,G. Q. Cheng,ZH. H. Huang 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.2

In safety analysis of structures, classical probabilistic analysis has been a popular approach in engineering. However, it is not always to obtain sufficient information to model all uncertain parameters of structures system by probability theory, especially at early stage of design. Under this circumstance, probability theory (used to model random uncertainty) combined with evidence theory (used to model epistemic uncertainty) may be utilized in safety analysis of structures. This paper proposed a novel method for safety analysis of structures based on probability and evidence theory. Firstly, Bayes conversion method is used as the way for precision of evidence body, and the mean and variance of epistemic uncertain variables is defined. Then epistemic uncertainty variables is transformed to normal random variables by reflection transformation method, and the checking point method (J-C method) is used to solve most probability point and reliability. A numerical example and two engineering examples are given to demonstrate the performance of the proposed method. The results show both precision and computational efficiency of the method is high. Moreover, the proposed method provides basis for reliability-based optimization with the hybrid uncertainties.

Formulation, release characteristics and bioavailability of novel monolithic hydroxypropylmethylcellulose matrix tablets containing acetaminophen

Cao, Q.R.,Choi, Y.W.,Cui, J.H.,Lee, B.J. Elsevier Science Publishers 2005 Journal of controlled release Vol.108 No.2

Effect of incorporating pharmaceutical excipients on the in vitro release profiles and the release mechanism of monolithic hydroxypropylmethylcellulose (4000 cps) matrix tablets (m-HPMC tablets) in terms of mimicking the dual drug release character of bi-layered Tylenol® ER tablets was studied. We also compared the in vitro release profiles of optimized m-HPMC matrix tablet and Tylenol® ER tablet in water, pH 1.2 gastric fluid, and pH 6.8 intestinal fluid, and in vivo drug bioavailabilities in healthy human volunteers. Acetaminophen was used as the model drug. The m-HPMC tablets were prepared using a wet granulation method followed by direct compression. Release profiles and swelling rates of m-HPMC tablets were found to be highly influenced by the types and amounts of pharmaceutical excipients incorporated. Starch 1500 (Prejel®) and sodium lauryl sulfate (SLS) played a key role in determining the dissolution rate of m-HPMC tablets. Additional excipients, i.e., microcrystalline cellulose (Avicel® PH101) and NaH<SUB>2</SUB>PO<SUB>4</SUB> were used to tune the release profiles of m-HPMC tablets. The effect of pharmaceutical excipients on drug release from HPMC-based matrix tablets was found to be mainly due to a change in hydrophilic gel expansion and on physical interactions between the drug and HPMC. The optimized m-HPMC tablet with a balanced ratio of Prejel®, SLS, Avicel® PH101, and NaH<SUB>2</SUB>PO<SUB>4</SUB> in the formulation showed dual release profiles in water, pH 1.2 gastric fluid, and pH 6.8 intestinal fluid in vitro. Dual release was defined as immediate drug release within few minutes followed by extended release over 8 h. The similarity factors of m-HPMC tablets and bi-layered Tylenol® ER tablets were 79.8, 66.1, and 82.7 in water, gastric fluid and intestinal fluid, respectively, indicating the equivalence of the two release profiles. No significant in vivo bioavailability differences were observed in healthy human volunteers. The developed m-HPMC tablet with dual release characteristics can be easily prepared using a conventional high-speed tablet machine and could provide an alternative to commercially available bilayered Tylenol® ER tablets.