Mathematical models applied to dispersal of pest populations in greenhouse

T. V. Nguyen,C.Xia,B.K.Chung,H.Y.Kim,T.S.Chona 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.05

A genome project has been launched and aims to sequence total genome of Cotesia plutellae bracovirus. On this process, several open reading frames (ORFs) have been identified. This study was intended to clone and express protein tyrosine phosphatase genes, PTP1 and PTP6. The ORFs of these two genes consist of 900 and 891 bp, respectively. PTP1 and PTP6 are genes of a group of genes that has been implicated as important regulatory components in cell growth, differentiation and malignant transformation by certain viruses. In this work,we studied the cloning and expression patterns of these genes in Plutella xylostella, a lepidopteran host of C. plutellae. A polymerase chain reaction (PCR) produced the corresponding products of PTP1/6. These PCR products were cloned and expressed using an expression vector pBAD-TOPO, and then over-expressed using an inducer, L-arabinose. Then the purified proteins were confirmed using Western blotting (immunoblotting using V5 antibody) and the apparent molecular weights of both proteins were about 40 kDa. Expression of PTP genes were analyzed in the parasitized P. xylostella by realtime RT-PCR, which indicated late expression pattern of both PTPs during parasitization. We are pursuing to elucidate their physiological function in the parasitized host insect.

Changes of Plasma Metabolites, Hormones, and mRNA Expression of Liver PEPCK-C in Spontaneously Ketotic Dairy Cows

Xia, C.,Wang, Z.,Liu, G.W.,Zhang, H.Y.,Zhang, C.,Xu, C. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.1

The objective of this study was to understand changes of plasma metabolites, hormones, and mRNA level of cytoplasmic phosphoenolpyruvate carboxykinase (PEPCK-C) in liver in spontaneous clinical ketosis; 10 clinically ketotic cows and 10 healthy cows were chosen from the same dairy farm. Eleven blood parameters and liver fat content were measured in all cows, and mRNA levels of PEPCK-C in liver were measured by semi-quantitative reverse transcription (RT) polymerase chain reaction (PCR). In ketotic cows, concentration of plasma glucose decreased (p<0.01), concentration of plasma nonesterified fatty acids (NEFA) and $\beta$-hydroxybutyric acid (BHBA) increased (p<0.01), liver fat content (18.8% wet weight) and activity of plasma aspartate aminotransferase (AST) increased (p<0.01), but concentration of plasma total bilirubin (TBIL), $\gamma$-glutamyl transpeptidase ($\gamma$-GT), and cholinesterase (CHE) increased (p>0.05). In addition, concentration of plasma insulin decreased (p<0.05), concentration of plasma glucagons decreased (p>0.05), and mRNA level of PEPCK-C in liver increased (p<0.05). It is concluded that the adaptative changes of metabolites, hormones, and mRNA level of PEPCK-C in ketotic cows were in favor of the enhancement of gluconeogenesis, the decrease of fat mobilization and the relief of ketosis, but these were still inadequate to relieve ketosis.

Plant leaf detection using modified active shape models

Xia, C.,Lee, J.M.,Li, Y.,Song, Y.H.,Chung, B.K.,Chon, T.S. Academic Press 2013 BIOSYSTEMS ENGINEERING Vol.116 No.1

We propose an in situ detection method of multiple leaves with overlapping and occlusion in greenhouse conditions. Initially a multilayer perceptron (MLP) is used to classify partial boundary images of pepper leaves. After the partial leaf boundary detection, active shape models (ASMs) are subsequently built to employ the images of entire leaves based on a priori knowledge using landmark. Two deformable models were developed with pepper leaves: Boundary-ASM and MLP-ASM. Matching processes are carried out by deforming the trained leaf models to fit real leaf images collected in the greenhouse. MLP-ASM detected 76.7 and 87.8% of overlapping and occluded pepper leaves respectively, while Boundary-ASM showed detection rates of 63.4 and 76.7%. The detection rates by the conventional ASM were 23.3 and 29.3%. The leaf models trained with pepper leaves were further tested with leaves of paprika, in the same family but with more complex shapes (e.g., holes and rolling). Although the overall detection rates were somewhat lower than those for pepper, the rates for the occluded and overlapping leaves of paprika were still higher with MLP-ASM (ranging from 60.4 to 76.7%) and Boundary-ASM (ranging from 50.5 to 63.3%) than using the conventional active shape model (from 21.6 to 30.0%). The modified active shape models with the boundary classifier could be an efficient means for detecting multiple leaves in field conditions.

Dynamic interaction analysis of a LIM train and elevated bridge system

H. Xia,W. W. Guo,C. Y. Xia,Y.-L. Pi,M. A. Bradford 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.12

A three-dimensional dynamic interaction model is developed for a LIM (linear induction motor) train and elevated bridge system, which is composed of a LIM-driven vehicle submodel and a finite element bridge submodel. Each LIM vehicle is modeled by a 27 degrees-of-freedom dynamic system. The expressions for the electromagnetic force between the linear motor and the reaction plate are derived, and the force model is established. By applying a modal superposition technique to the bridge submodel and using the measured track irregularities as the self-excitations of the train-bridge system, the equations of motion are established for analyzing the dynamic responses of the LIM vehicle and the elevated bridge. The proposed framework is applied to a 3-span elevated bridge with 29.9 m simply-supported girders. The full histories of the LIM train traversing the bridge are simulated, from which the dynamic responses of the LIM vehicle and elevated bridge system are obtained. The proposed method may help to find a way to assess the dynamic properties of elevated bridges and the running safety of a LIM train with reasonable computational effort.

SYNTHESIS OF POLYBENZONITRILE WITH ULTRAFAST OPTICAL KERR EFFECT

Zhao, X.Y,Xu, Q,He, Y.K,Chen, H.Y,Wang, C.F,Ai, X.C,Xia, Z.J,Zou, Y.H 한국재료학회 1995 Fabrication and Characterization of Advanced Mater Vol.1 No.3

Plasma polymerization of benzonitrile was carried out with RF glow discharge system. The polymer was characterized by FT-IR, UV-VIS, and Elemental Analysis. the molecular weitht was determined by vapor pressure osmometer. for the first time the nonresonant optical Kerr effect(OKE) of plasma polymerized benzonitrile was measured, and a power law dependence of ${\gamma}_{1111}$ on average polymerization degree was discussed. An ultrafast response was also observed.

Observation of the topological surface state in the nonsymmorphic topological insulator KHgSb

Liang, A. J.,Jiang, J.,Wang, M. X.,Sun, Y.,Kumar, N.,Shekhar, C.,Chen, C.,Peng, H.,Wang, C. W.,Xu, X.,Yang, H. F.,Cui, S. T.,Hong, G. H.,Xia, Y.-Y.,Mo, S.-K.,Gao, Q.,Zhou, X. J.,Yang, L. X.,Felser, C. American Physical Society 2017 Physical review. B Vol.96 No.16

<P>Topological insulators represent unusual topological quantum states, typically with gapped bulk band structure but gapless surface Dirac fermions protected by time-reversal symmetry. Recently, a distinct kind of topological insulator resulting from nonsymmorphic crystalline symmetry was proposed in the KHgX (X = As, Sb, Bi) compounds. Unlike regular topological crystalline insulators, the nonsymmorphic glide-reflection symmetry in KHgX guarantees the appearance of an exotic surface fermion with hourglass shape dispersion (where two pairs of branches switch their partners) residing on its (010) side surface, contrasting to the usual two-dimensional Dirac fermion form. Here, by using high-resolution angle-resolved photoemission spectroscopy, we systematically investigate the electronic structures of KHgSb on both (001) and (010) surfaces and reveal the unique in-gap surface states on the (010) surface with delicate dispersion consistent with the 'hourglass Fermion' recently proposed. Our experiment strongly supports that KHgSb is a nonsymmorphic topological crystalline insulator with hourglass fermions, which serves as an important step to the discovery of unique topological quantum materials and exotic fermions protected by nonsymmorphic crystalline symmetry.</P>

R&D Status of High-current Accelerators at IFP

J. J. Deng,J. S. Shi,W. P. Xie,L. W. Zhang,K. Z. Zhang,S. P. Feng,J. Li,M. Wang,Y. He,L. S. Xia,Z. Y. Dai,H. T. Li,L. Wen,S. F. Chen,X. Li,Q. G. Lai,M. H. Xia,Y. C. Guan,S. Y. Song,L. Chen 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

High-current accelerators have many important applications in Z-pinches, high-power microwaves, and free electron lasers, imploding liners and radiography and so on. Research activities on Zpinches, imploding liners, radiography at the Institute of Fluid Physics (IFP) are introduced. Several main high-current accelerators developed and being developed at IFP are described, such as the Linear Induction Accelerator X-Ray Facility Upgrade (LIAXFU, 12 MeV, 2.5 kA, 90 ns), the Dragon-I linear induction accelerator (20 MeV, 2.5 kA, 60 ns), and the Primary Test Stand for Z-pinch (PTS, 10 MA, 120 ns). The design of Dragon-II linear induction accelerator (20 MeV, 2.5 kA, 3 × 60 ns) to be built will be presented briefly.

Characterization of porosity in sulfide ore minerals: A USANS/SANS study

Xia, F.,Zhao, J.,Etschmann, B.E.,Brugger, J.,Garvey, C.J.,Rehm, C.,Lemmel, H.,Ilavsky, J.,Han, Y.-S.,Pring, A. MINERALOGICAL SOCIETY OF AMERICA 2014 The American mineralogist Vol.99 No.11

Effects of Copper-bearing Montmorillonite (Cu-MMT) on Escherichia coli and Diarrhea on Weanling Pigs

Xia, M.S.,Hu, C.H.,Xu, Z.R.,Ye, Y.,Zhou, Y.H.,Xiong, L. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.12

Copper-bearing montmorillonite (Cu-MMT) was produced by $Cu^{2+}$ cation exchange reaction. X-ray diffraction analysis showed that that the (001) basal spacing of the MMT crystal lattice increased from 1.544 to 1.588 nm after $Cu^{2+}$ exchange. This indicated that $Cu^{2+}$ entered into interlayer position of MMT as a hydrated cation or composite cation. In vitro results indicated that Cu-MMT had antibacterial activity on Escherichia coli $K_{88}$. Cu-MMT had unbalanced positive charge after cation exchange. Its antibacterial activity resulted from two aspects, one was electrostatic attraction which made E. coli $K_{88}$ being adhered on the montmorillonite surface, the other was the $Cu^{2+}$ slowly released, which could kill bacteria. In an in vivo study, four replicates of eight weanling pigs were assigned to each of two dietary treatments to study the effects of Cu-MMT on diarrhea, E. coli in the lumen of the jejunum and morphology of jejunal mucosa. As compared to the control, supplementation of the diet with 0.2% Cu-MMT improved average daily gain by 12.50% (p<0.05) and decreased F/G by 9.42% (p<0.05). The mean diarrhrea incidence was decreased by 71.80% (p<0.05). The viable counts of Escherichia coli in jejunal contents were significantly reduced (p<0.05). Villus height and the villus height to crypt depth ratio at the jejunal mucosa were increased by 19.09% (p<0.05) and 37.10% (p<0.05), respectively.

Radiation induced grain boundary segregation in ferritic/martensitic steels

Xia, L.D.,Ji, Y.Z.,Liu, W.B.,Chen, H.,Yang, Z.G.,Zhang, C.,Chen, L.Q. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.1

The radiation induced segregation of Cr at grain boundaries (GBs) in Ferritic/Martensitic steels was modeled assuming vacancy and interstitialcy diffusion mechanisms. In particular, the dependence of segregation on temperature and grain boundary misorientation angle was analyzed. It is found that Cr enriches at grain boundaries at low temperatures primarily through the interstitialcy mechanism while depletes at high temperatures predominantly through the vacancy mechanism. There is a crossover from Cr enrichment to depletion at an intermediate temperature where the Cr:Fe vacancy and interstitialcy diffusion coefficient ratios intersect. The bell-shape Cr enrichment response is attributed to the decreasing void sinks inside the grains as temperature rises. It is also shown that low angle grain boundaries (LAGBs) and special Σ coincidence-site lattice (CSL) grain boundaries exhibit suppressed radiation induced segregation (RIS) response while high angle grain boundaries (HAGBs) have high RIS segregation. This different behavior is attributed to the variations in dislocation density at different grain boundaries.