Quantifying herbicide dose-response and resistance in <i>Echinochloa</i> spp. by measuring root length in growth pouches

Zhang, C. J.,Lim, S. H.,Kim, J. W.,Song, J. S.,Yook, M. J.,Nah, G.,Valverde, B. E.,Kim, D. S. Canadian Science Publishing 2015 Canadian journal of plant science. Revue canadienn Vol.95 No.6

<P> Zhang, C. J., Lim, S. H., Kim, J. W., Song, J. S., Yook, M. J., Nah, G., Valverde, N. E. and Kim, D. S. 2015. Quantifying herbicide dose-response and resistance in Echinochloa spp. by measuring root length in growth pouches. Can. J. Plant Sci. 95: 1181-1192. The aim of the presented study was to develop a bioassay for rapid diagnosis of herbicide dose-response and resistance in Echinochloa. Pre-germinated seeds of Echinochloa spp. were incubated in growth pouches (18 cm×16.5 cm) containing herbicide solutions in a range of concentrations. Shoot and root lengths were measured after 6 d of incubation. Dose-responses estimated by measuring root lengths in the growth pouches were well-described by the log-logistic dose-response model and similar to those estimated by a whole-plant assay. Accurate dose-response curves were successfully generated for several herbicides with different modes of action, suggesting that the growth pouch method can be used for herbicide bioassays. The suitability of the growth pouch method for rapid diagnosis of acetyl coenzyme-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor resistance in Echinochloa spp. was also tested. For cyhalofop-butyl, resistant and susceptible biotypes were discriminated at 180-300 mg a.i. L<SUP>−1</SUP> and 80-120 mg a.i. L<SUP>−1</SUP> for barnyardgrass (E. crus-galli) and late watergrass (E. oryzicola), respectively. For penoxsulam, the discriminatory dosage was 350-500 mg a.i. L<SUP>−1</SUP> for barnyardgrass and 650-1000 mg a.i. L<SUP>−1</SUP> for late watergrass. The method was further used to identify late watergrass biotypes resistant and susceptible to two other ALS inhibitors, azimsulfuron and bispyribac-sodium. Our results show that the growth pouch method can be reliably used in herbicide dose-response studies and to diagnose herbicide resistance in Echinochloa spp., with significant time and cost savings compared with conventional whole-plant assays. </P>

Optical spectroscopy of PPV-based block copolymers of nanostructured supramolecular organic semiconductor.

Yang, Q,Battle, R,Zhang, C,Ma, S M,Seo, J T,Tabibi, B,Temple, D,Sun, S,Jung, S S,Namkung, M American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.2

<P>The third-order nonlinearity of a PPV-based nanostructured supramolecular organic semiconductor (DBAB), with an electron donor (D) connected to an electron acceptor (A) via nonconjugated and flexible bridge (B) units, was investigated in this work at both near-resonant (532 nm) and nonresonant (1064 nm) wavelength by using degenerate four-wave mixing. The second hyperpolarizabilities of D, A, and DBAB at 532 nm were found to be approximately 2.42 x 10(-43) m2/V2, 7.75 x 10(-44) m2/V2, and 1.80 x 10(-43) m2/V2 in copolarization geometry, and approximately 1.59 x 10(-43) m2/V2, 2.59 x 10(-44) m2/V2, and 1.18 x 10(-43) m2/V2 in orthogonal polarization geometry, respectively. The second hyperpolarizabilities of DBAB at 1064 nm were approximately 1.66 x 10(-46) m2/V2 and approximately 8.77 x 10(-47) m2/V2 for parallel and orthogonal polarization cases.</P>

Cu addition and its role in thermoelectric properties and nanostructuring in the series compounds (InSb)nCum

J.L. Cui,Y.M. Yan,H. Fu,X.J. Zhang,Y.L. Gao,Y. Deng 한국물리학회 2012 Current Applied Physics Vol.12 No.1

We have performed a comparative investigation of the series compounds (InSb)nCum to assess the roles of Cu addition on the thermoelectric properties and nanostructuring in bulk InSb. Detailed temperature dependent transport properties including electrical conductivity, the Seebeck coefficient, and thermal conductivity are presented. The Seebeck coefficients of In20Sb20Cu (m:n ¼ 1:20) are increased by 13percent in magnitude if compared to those of InSb, which is responsible for the 22 percent enhancement in the highest ZT value at 687 K. Although the magnitudes of kL are larger than those of InSb over the entire temperature range, a remarkable reduction in lattice thermal conductivities (kL) was observed with measuring temperature elevation. Such changes are mainly due to the precipitation of a large number of Cu9In4 nanoparticles with the size of smaller than 5 nm, dispersed in the matrix observed using high resolution transmission electron microscopy (HRTEM) images.

The Origin of Coercivity Enhancement of Sintered NdFeB Magnets Prepared by Dy Addition

N. J. Yu,M. X. Pan,P. Y. Zhang,H. L. Ge 한국자기학회 2013 Journal of Magnetics Vol.18 No.3

The effect of Dy addition on the microstructure and magnetic properties of the sintered NdFeB magnets was investigated. The results of the microstructure analysis showed that Dy-free and Dy-doped samples are composed of Nd₂Fe ₁₄B (P42/mnm) and a trace of Nd-rich phase. Dy addition reduces significantly the pole density factor of (004), (006) and (008) crystal faces as estimated by the Horta formula. Accordingly, the coercivity of the Dy-doped sample increases from 2038 kA·m?1 up to 2288 kA·m?1. The Hcj(T)/Ms(T) versus /Ms(T) (Kronmuller-plot) behavior shows that the nucleation is the dominating mechanism for the magnetization reversal in these two kinds of magnets, and two microstructural parameters of αk and Neff are obtained. The Kronmuller-Plot gives evidence for an increase of the αk responsible for an increase of the coercivity as the result of the increase of the magnetic field as the magnetic domain reversed.

Interfacial fabrication and property of hydroxyapatite/polylactideresorbable bone fixation composites

S.M. Zhang,J. Liu,W. Zhou,L. Cheng,X.D. Guo 한국물리학회 2005 Current Applied Physics Vol.5 No.5

Based on surface modication of hydroxyapatite with silane derivatives, interfacial fabrications of hydroxyapatite (HAP)/poly-lactide (PLA) resorbable bone xation composites are realized. The results indicate that interfacial adhesion, swelling property, andultimate mechanical properties of the HAP/PLA composites are signicantly improved. As a result, the maximum bending strengthenhances 27.8%. Scanning electron microscopy (SEM) observation suggests that the modied HA particles are homogeneously dis-persed in the composites, their size ranges are about 215l m. The modied HA/PLA composites are of toughened rupture. Thisconclusion is consistent with bending property of the composites. Finally, a possible mechanism for the interfacial adhesion is alsodiscussed..

Effects of Brazing Temperature on Microstructure and High-Temperature Strength of Joints Using a Novel Fourth-Generation Nickel-Based Single Crystal Superalloy

Z. P. Zhang,J. D. Liu,K. Q. Qiu,Y. Y. Huang,J. G. Li,X. G. Wang,J. L. Liu,M. Wang,M. K. Zou,Y. Z. Zhou 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

A novel fourth-generation nickel-based single crystal superalloy was bonded by vacuum brazing at 1230 °C, 1260 °C and1290 °C for 60 min using a new type of Co-based filler alloy. The effects of the brazing temperature on the microstructureand mechanical properties of the brazed joint were investigated. The brazed joint was mainly composed of the non-isothermalsolidification zone (M3B2 type-boride, CrB boride, Ni3Bboride and MC carbide), isothermal solidification zone (γ and γ'Phase) and base metal. With the increase of brazing temperature, the volume fraction of borides and γ' phase in the centerof the joint decreased and increased, respectively. The high-temperature tensile test results show that the tensile strength ofthe joints was improved with increasing brazing temperature, and the maximum tensile strength of the joint was 766 MPaafter brazing at 1290 °C for 60 min. Fracture observation shows that the fracture modes of the joints were the same, whichbelongs to the typical quasi cleavage fracture. The element distribution in the joint was homogenized to a certain extent at1290 °C. The segregation of Si and Ru was found, but they were still dissolved in the γ solid solution. The experimentalresults help to better understand the microstructure characteristics of the novel fourth-generation nickel-based single crystalsuperalloy and provide guidance for further optimizing the process parameters of the brazed joint.

Tokamak plasma disruption precursor onset time study based on semi-supervised anomaly detection

X.K. Ai,W. Zheng,M. Zhang,D.L. Chen,C.S. Shen,B.H. Guo,B.J. Xiao,Y. Zhong,N.C. Wang,Z.J. Yang,Z.P. Chen,Z.Y. Chen,Y.H. Ding,Y. Pan Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.4

Plasma disruption in tokamak experiments is a challenging issue that causes damage to the device. Reliable prediction methods are needed, but the lack of full understanding of plasma disruption limits the effectiveness of physics-driven methods. Data-driven methods based on supervised learning are commonly used, and they rely on labelled training data. However, manual labelling of disruption precursors is a time-consuming and challenging task, as some precursors are difficult to accurately identify. The mainstream labelling methods assume that the precursor onset occurs at a fixed time before disruption, which leads to mislabeled samples and suboptimal prediction performance. In this paper, we present disruption prediction methods based on anomaly detection to address these issues, demonstrating good prediction performance on J-TEXT and EAST. By evaluating precursor onset times using different anomaly detection algorithms, it is found that labelling methods can be improved since the onset times of different shots are not necessarily the same. The study optimizes precursor labelling using the onset times inferred by the anomaly detection predictor and test the optimized labels on supervised learning disruption predictors. The results on J-TEXT and EAST show that the models trained on the optimized labels outperform those trained on fixed onset time labels.

Sensitivity of surface characteristics on the simulation of wind-blown-dust source in North America

Park, S.H.,Gong, S.L.,Gong, W.,Makar, P.A.,Moran, M.D.,Stroud, C.A.,Zhang, J. Pergamon Press ; Elsevier [distribution] 2009 Atmospheric environment Vol.43 No.19

Recently, a wind-blown-dust-emission module has been built based on a state-of-the-art wind erosion theory and evaluated in a regional air-quality model to simulate a North American dust storm episode in April 2001 (see Park, S.H., Gong, S.L., Zhao, T.L., Vet, R.J., Bouchet, V.S., Gong, W., Makar, P.A., Moran, M.D., Stroud, C., Zhang, J. 2007. Simulation of entrainment and transport of dust particles within North America in April 2001 (''Red Dust episode''). J. Geophys. Res. 112, D20209, doi:10.1029/2007JD008443). A satisfactorily detailed assessment of that module, however, was not possible because of a lack of information on some module inputs, especially soil moisture content. In this paper, the wind-blown-dust emission was evaluated for two additional dust storms using improved soil moisture inputs. The surface characteristics of the wind-blown-dust source areas in southwestern North America were also investigated, focusing on their implications for wind-blown-dust emissions. The improved soil moisture inputs enabled the sensitivity of other important surface characteristics, the soil grain size distribution and the land-cover, to dust emission to be investigated with more confidence. Simulations of the two 2003 dust storm episodes suggested that wind-blown-dust emissions from the desert areas in southwestern North America are dominated by emissions from dry playas covered with accumulated alluvial deposits whose particle size is much smaller than usual desert sands. As well, the source areas in the northwestern Texas region were indicated to be not desert but rather agricultural lands that were ''activated'' as a wind-blown-dust sources after harvest. This finding calls for revisions to the current wind-blown-dust-emission module, in which ''desert'' is designated to be the only land-cover category that can emit wind-blown dust.

Temporal variations of black carbon in Guangzhou, China, in summer 2006

Verma, R. L.,Sahu, L. K.,Kondo, Y.,Takegawa, N.,Han, S.,Jung, J. S.,Kim, Y. J.,Fan, S.,Sugimoto, N.,Shammaa, M. H.,Zhang, Y. H.,Zhao, Y. Copernicus GmbH 2010 Atmospheric Chemistry and Physics Vol.10 No.14

<P>Abstract. In situ measurements of the mass concentration of black carbon (BC) and mixing ratios of carbon monoxide (CO) and carbon dioxide (CO2) were made at Guangzhou, an urban measurement site in the Pearl River Delta (PRD), China, in July 2006. The average ± standard deviation (SD) concentrations of BC, CO, and CO2 were 4.7± 2.3 μgC m−3, 798± 459 ppbv, and 400± 13 ppmv, respectively. The trends of these species were mainly controlled by synoptic-scale changes in meteorology during the campaign. Based on back trajectories, data are analyzed separately for two different air mass types representing northerly and southerly flows. The northerly air masses, which constituted ~25% of the campaign, originated mostly in the PRD and hence represent observations on regional scales. On the other hand, during southerly flow (~75%), the measurements were influenced by dilution due to cleaner marine air. The diurnal patterns of BC, CO, and CO2 exhibited peak concentrations during the morning and evening hours coinciding with rush-hour traffic. The ratios of OC/BC were lower during the morning hour peaks in the concentrations of primary pollutants due to their fresh emissions mainly from vehicular traffic in Guangzhou. The diurnal variations of BC observed in southerly air masses tended to follow the traffic patterns of heavy-duty vehicles (HDV) in Guangzhou, while the roles of other sources need to be investigated. The slopes of ΔBC/ΔCO, ΔBC/ΔCO2, and ΔCO/ΔCO2 observed during northerly flows were 0.0045 μgC m−3/ppbv, 0.13 μgC m−3/ppmv, and 49.4 ppbv/ppmv, respectively, agreeing reasonably with their respective emission ratios derived from regional emission inventories. </P>

Application of a sorbent trap system to gas-phase elemental and oxidized mercury analysis

Zhang, Z.,Eom, Y.,Lee, M.J.,Lee, T.G. Pergamon Press 2016 CHEMOSPHERE - Vol.154 No.-

A sorbent trap that utilizes activated carbon (AC) as the solid trapping medium is a new technology for measuring total mercury (Hg) emissions from combustion facilities. In this study, sorbent trap technology was further developed, improved and evaluated at the laboratory scale. AC was impregnated with 5% aqua regia to enhance its Hg adsorption capacity. Sorbent traps spiked with an Hg standard solution were found to be reproducibly prepared and highly stable. The effect of the Hg concentration on the spiking efficiency was further investigated. The adsorption of elemental and oxidized Hg by the sorbent trap was studied under various experimental conditions (temperature, flow rate and inlet Hg concentration). The Hg concentration of the flue gas effluent from the sorbent trap was measured. In addition, the concentration of Hg adsorbed on the AC was determined by digesting the used AC with an acid according to US EPA method 3052 and then analyzing it with cold vapor atomic absorption spectrometry. Furthermore, the gas-phase Hg emissions from a combustion source were measured using the sorbent trap according to US EPA method 30B. The results showed that the sorbent trap could be used for Hg concentrations between 10.0 and 40.0 μg m<SUP>-3</SUP> and flow rates between 0.5 and 1.0 lpm with adsorption efficiencies greater than 90%.