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The pressures produced by underwater explosions present serious threats to ships, submarines, and other marine structures. A significant part of underwater explosion pressure comes from the explosion bubble. Most computational studies on bubble pressure have considered the case of an incompressible fluid or have confined calculations to the time before the formation of a toroidal bubble, because of the complexity and strong nonlinearity of a compressible flow field with a doubly connected geometry. The few compressible models that are capable of calculating the pressure after jet impact suffer from computational difficulties. In this paper, we calculate the bubble pressure by constructing a new form for solving an auxiliary function based on a boundary integral method that takes account of the compressibility of the flow field. We verify out numerical algorithm by comparison with a classical theoretical model and a set of experimental results. We then compare the bubble pressure in a compressible flow field in both the first and second oscillation periods with that in an incompressible flow field. The results of this comparison confirm that it is necessary to consider the compressibility of the fluid and the multiperiod pulsations of a bubble in pressure calculations. We present a comprehensive discussion of the pressure characteristics in the central axial and circumferential directions induced by a nonspherical bubble in a free field. Finally, we obtain a critical bubble–wall distance r w > 1.8 for which the bubble is prevented from splitting after the first jet impact, and we investigate the pressure characteristics of a bubble near a rigid wall for both cases of r w < 1.8 and r w > 1.8. [ABSTRACT FROM AUTHOR]

Y2O3:Eu3+,Tb3+,Ce3+ phosphors were prepared by the co-precipitation method and the optimal component formulations of the samples were determined by a combination of controlled variable method and orthogonal experiments. The experimental results show that doping with appropriate amounts of Tb3+ and Ce3+ significantly improved the luminescence performance of Y2O3:Eu3+ phosphors. In the Y2O3:Eu3+,Tb3+,Ce3+ phosphors system, Tb3+ could be used as a carrier to transfer energy for Ce3+–Eu3+, eliminating the presence of metal–metal charge transfer (MMCT) between the two ions. The direction of energy transfer which is from Ce3+ → Tb3+ → Eu3+ has been confirmed by emission spectrum and calculation results show that the mechanism of Tb3+ to Eu3+ energy transfer and Ce3+ to Tb3+ energy transfer in Y2O3 matrix are both quaternary–quaternary interactions. As the doping concentration of Tb3+ and Ce3+ increases, the emission peak position of phosphor was shifted toward the blue region. Their structure and micromorphology have been analyzed by X-ray diffraction and scanning electron microscopy, the test results show that ion doping does not cause changes in the crystal structure of Y2O3 and the samples are approximately spherical in shape. This work provides a new idea to study the UV detection and multi-ion inter-energy transfer model. [ABSTRACT FROM AUTHOR]

Spatial transcriptomics unveils the complex dynamics of cell regulation and transcriptomes, but it is typically cost-prohibitive. Predicting spatial gene expression from histological images via artificial intelligence offers a more affordable option, yet existing methods fall short in extracting deep-level information from pathological images. In this paper, we present THItoGene, a hybrid neural network that utilizes dynamic convolutional and capsule networks to adaptively sense potential molecular signals in histological images for exploring the relationship between high-resolution pathology image phenotypes and regulation of gene expression. A comprehensive benchmark evaluation using datasets from human breast cancer and cutaneous squamous cell carcinoma has demonstrated the superior performance of THItoGene in spatial gene expression prediction. Moreover, THItoGene has demonstrated its capacity to decipher both the spatial context and enrichment signals within specific tissue regions. THItoGene can be freely accessed at https://github.com/yrjia1015/THItoGene. [ABSTRACT FROM AUTHOR]

Carbon nitride (CN) has been widely used in photomineralization of phenolic pollutants, during which avoiding the production of refractory polymers induced by hydroxyl radical (•OH) is the key. In CN photocatalytic system, O 2 firstly reduces to superoxide radical (O 2 •-), then transforms into hydrogen peroxide (H 2 O 2) via reduction and protonation process, finally reduces into •OH. In this study, OH/C V -CN, hydroxyl groups (–OH) and carbon vacancies (C V) co-modified CN, was designed for phenol photomineralization. –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing C V into CN during roasting process. C V , active sites for reducing O 2 to O 2 •-, is close to adsorption sites of phenol, which greatly promotes the in-situ mineralization of phenol by O 2 •- and avoids the polymerization induced by •OH. Therefore, –OH and C V in OH/C V -CN synergistically facilitate the photomineralization of phenol. [Display omitted] • –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing C V into carbon nitride through adjusting the electron distribution on the adjacent heptazine. • C V , locating on the same heptazine ring with –OH, realize the rapid transformation of O 2 to O 2 •- as O 2 adsorption sites. • O 2 •- in-situ mineralize phenol instead of reducing to •OH profited from the shorter distance between O 2 •- and adsorbed phenol on OH/C V -CN than CN, which facilitates effective photomineralization of phenol and cleverly prevent forming polymer. Carbon vacancies Carbon nitride (CN) has been widely used in photomineralization of phenolic pollutants, during which avoiding the production of refractory polymers induced by hydroxyl radical (•OH) is the key. In CN photocatalytic system, O 2 firstly reduces to superoxide radical (O 2 •-), then transforms into hydrogen peroxide (H 2 O 2) via reduction and protonation process, finally reduces into •OH. In this study, OH/C V -CN, hydroxyl groups (–OH) and carbon vacancies (C V) co-modified CN, was designed for phenol photomineralization. –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing C V into CN during roasting process. C V , active sites for reducing O 2 to O 2 •-, is close to adsorption sites of phenol, which greatly promotes the in-situ mineralization of phenol by O 2 •- and avoids the polymerization induced by •OH. Therefore, –OH and C V in OH/C V -CN synergistically facilitate the photomineralization of phenol. [ABSTRACT FROM AUTHOR]

Recently, Ledoux, Nair, and Wang proved that the Fisher information along the heat flow is log-convex in dimension one, that is d 2 d t 2 log (I (X t)) ≥ 0 for n = 1 , where X t is a random variable with density function satisfying the heat equation. In this paper, we consider the high dimensional case and prove that the Fisher information is square root convex in dimension two, that is d 2 d t 2 I X ≥ 0 for n = 2 . The proof is based on the semidefinite programming approach. [ABSTRACT FROM AUTHOR]

Although black soldier fly larvae (BSFL) can convert food waste into insectile fatty acids (FAs), the chronological and diet-dependent transformation of larval FAs has yet to be determined. This study focused on the dynamics of larval FA profiles following food waste treatment and characterized factors that may drive FA composition and bioaccumulation. Larval FA matters peaked on Day 11 as 7.7 ± 0.7% of food waste dry matter, maintained stably from Day 11–19, and decreased slightly from Day 19–21. The BSFL primarily utilized waste carbohydrates for FA bioconversion (Day 0–11) and shifted to waste FAs (Day 7–17) when the carbohydrates were close to depletion. The optimal time window for larvae harvest was Days 17–19, which fulfilled both targets of waste oil removal and larval FA transformation. Larval FAs were dominated by C12:0, followed by C18:2, C18:1, and C16:0. The waste-reducing carbohydrate primarily accounted for larval FA bioaccumulation (r = −0.947, p < 0.001). The increase in diet carbohydrate ratio resulted in the elevation of larval C12:0 yield, which indicated that larval C12:0-FA was primarily biosynthesized from carbohydrates and further transformed from ≥C16 FAs. This study elucidates the bioaccumulation process of larval FAs for food waste treatment and highlights the importance of waste carbohydrates for both the composition and transformation of larval FAs. [ABSTRACT FROM AUTHOR]

An extended measurement model anomaly detection algorithm for atomic clocks is proposed based on the p-step Kalman-like iterative Unbiased finite impulse response (UFIR) algorithm. The novel of the proposed algorithm is that it breaks the disadvantage of initializing the noise matrix in the traditional Kalman filter improved algorithms. By accumulating the prediction residuals generated by the process of p-step Kalman-like iterative, the detection statistics are constructed to realize the weaker phase and frequency jump detection of atomic clocks. Simulation results show the effectiveness of the proposed algorithm, and Monte-Carlo (M-C) experiment is used to verify the theoretical calculation of detection probability. We also analyze the measured data of a cesium atomic clock in our timekeeping laboratory, and the results show that the new method is more sensitive to weak frequency jump than the improved algorithm based on the Kalman filter. [ABSTRACT FROM AUTHOR]

Automated chemical synthesizers have become more common in recent years but struggle to apply rigid procedures to broad substrate scopes. We have developed an adaptive auto‐synthesizer that uses online HPLC and FTIR measurements to adapt to the changing reactivities of different substrates, allowing precise control of reaction conditions. To do so, we designed a flexibly‐timed procedure consisting of specific actions performed by our platform when specific reaction‐monitoring checkpoints are met. Online HPLC allowed our system to autonomously separate, label and quantify most reaction components, with orthogonal FTIR enabling non‐UV active species to be additionally tracked. We tested our platform with CDI‐mediated multistep amidation reactions using a variety of different acid and amine substrates. To demonstrate the high reproducibility and control afforded by our system, we determined the relative rates of both acid activation and subsequent amidation, providing insight into substrate reactivities and the reaction mechanism. [ABSTRACT FROM AUTHOR]

Developing high-efficiency membrane for oil and dye removal is very urgent, because wastewater containing them can cause great damage to human and environment. In this study, a coated membrane was fabricated by applying DAC and PEI onto the commercial PVDF microfiltration membrane for supplying the demand. The coated membrane presents superhydrophlic and superoleophobic properties with a water contact angle of 0o and underwater oil contact angle exceed 150°, as well as excellent low underwater oil adhesion performance. The coated membrane shows high separation efficiency exceeded 99.0% and flux 350.0 L·m−2·h−1 when used for separating for six kinds of oil including pump oil, sunflower oil, n-hexadecane, soybean oil, diesel and kerosene in water emulsions. Additionally, the coated membrane can effectively remove anionic dyes, achieving rejection rates of 94.7%, 93.4%, 92.3%, 90.7% for the CR, MB, RB5, AR66, respectively. More importantly, the membrane was able to simultaneously remove emulsified oil and soluble anionic dyes in wastewater containing both of them. Therefore, this novel coated membrane can be a promising candidate for treating complex wastewater. [Display omitted] • The DAC and PEI were applied onto PVDF membrane surface for modification. • The coated membrane was high hydrophilicity and underwater superoleophobic. • The coated membrane can be used for separating different oil water emulsions. • The coated membrane can simultaneously remove emulsified oils and anionic dyes. [ABSTRACT FROM AUTHOR]

In this paper, the accuracy of wave parameters of the European Centre for Medium-Range Weather Forecasting Reanalysis v5 (ERA5) in the South China Sea (SCS) is systematically examined with field measured data of two buoys at offshore sites and a subsea-based platform at a nearshore site, which has a total observational period of nearly three years. It is suggested that the wave parameters provided by ERA5, such as significant wave height (Hs) and mean wave period (Tm), are in good agreement with the observational data of the three sites. Compared with the in situ data, the correlation coefficient of ERA5 Hs is in the range of 0.87–0.93, and the root mean square error is only in the range of 0.22–0.57 m. The error of standard deviation does not exceed 0.29 m and is even as low as 0.04 m at two sites. The wave propagation directions of the ERA5 and in situ data are also basically the same. However, when the data are applied in engineering, some wave parameters extracted from ERA5 may deviate from the measured statistics. It is possible to significantly overestimate the average duration of a particular Hs. Further analysis shows that the possible errors of ERA5 wave parameters may be due to insufficient description of topographic conditions, which shows that the error value changes obviously with the wave direction. The results preliminarily confirm the validity of ERA5 data in the SCS, but also indicate that it is necessary to calibrate and validate the data adequately when applying the global model and its reanalysis data to specific ocean areas. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-performance interfacial heterojunction, formed between OH PCN and Nb 2 O 5 via C O H O Nb bond, accelerates the carrier transfer from conduction band of Nb 2 O 5 to that of OH PCN. • The electron transfer occurred in C O H O Nb bond induces electron-rich O site, which act as an ideal adsorption site for phenol through O H ··· O hydrogen bond. • Super active site, formed by integrating triazine ring site on OH-PCN (activation site for O 2) and O site on Nb 2 O 5 (adsorption site for phenol), facilitates the evolution of O 2 and in-situ photomineralization of phenol. Promoting the carrier separation and surface catalytic reaction are critically important to maximize photocatalytic efficiency. Hydroxyl group-modified polymeric carbon nitride/niobium pentoxide nanosheets heterojunction (OH-PCN/Nb 2 O 5) is designed for fast electron transfer from Nb 2 O 5 to OH-PCN. Electron-rich O site, induced by electron transfer occurred in C O H O Nb bond, acts as an ideal adsorption site for phenol through O H⋯O bond. Super active site, formed by integrating triazine ring site on OH-PCN (activation site for O 2) and O site on Nb 2 O 5 (adsorption site for phenol), facilitates the evolution of O 2 and in-situ photomineralization of phenol. OH-PCN/Nb 2 O 5 shows a more than 8-fold improvement in phenol photodegradation efficiency than PCN. Briefly, this work provides insights on constructing interfacial super active sites by interface control of catalysts and in turn dramatically improving the photocatalytic performance. [ABSTRACT FROM AUTHOR]

This work presents a review of the current progress, challenges, and potential future development opportunities for two-dimensional (2D) material-based heterostructures, including their fabrication techniques as well as their applications in various functional devices. The fabrication techniques for 2D material-based vertical heterostructures are first reviewed and discussed, including artificial stacking, chemical vapor deposition (CVD), molecular beam epitaxy, and others. Then, 2D material-based lateral heterostructure growth techniques are reviewed, including CVD and others. Subsequently, various functional device applications based on 2D material-based heterostructures are systematically reviewed and discussed, including electronic devices, optoelectronic devices, electrochemical devices, and others. The advantages and disadvantages for each fabrication/growth technique are compared and analyzed, including those for both vertical and lateral heterostructures. In addition, the current primary challenges for further development of 2D material-based heterostructures and their functional devices are discussed and analyzed, including lack of precise control, low interface/surface quality, surface passivation issue, low light absorption, lack of system integration and application, complex device fabrication process, as well as low device fabrication efficiency. Various potential solutions are proposed that have the potential to overcome these existing primary challenges to achieve better device performance and thus their ultimate industry applications for2D material-based heterostructures. [ABSTRACT FROM AUTHOR]

A new method based on the innovation of Kalman filter and extrapolation-accumulation is proposed to detect weak frequency anomalies in atomic clocks with short detection time and high detection probability. In this method, the detection statistics of the innovation extrapolation method in several epochs are accumulated. It avoids the influence of outliers, increases the noncentrality parameter of chi-square distribution, and realizes more effective detection of weak frequency anomalies. The simulation results show that compared with the innovation method and the innovation extrapolation method, the new method has a higher detection probability for micro frequency anomalies, and the detection time is shortened. The new method is used to analyze the real data of the cesium atomic clock, and the results are consistent with the simulation results. [ABSTRACT FROM AUTHOR]

Secondary Ion Mass Spectrometry is an important technique for the study of the composition of a wide range of materials because of the exceptionally high sensitivity that allows the study of trace elements and the ability to distinguish isotopes that can be used as markers for reactions and transport processes. However, when studying nuclear materials, it is often necessary to analyse highly radioactive samples, and only rather few SIMS facilities are available in active environments. In this paper, we present a methodology using focussed ion beam milling to prepare samples from radioactive specimens that are sufficiently large to undertake SIMS mapping experiments over microstructurally significant regions, but with overall activities small enough to be readily transported and analysed by a SIMS instrument in a normal laboratory environment. Radioactive samples prepared using this methodology can also be used for correlative SIMS analysis with other analytical microscopies. SIMS results showing the distributions of deuterium in oxides on in‐reactor corroded zirconium alloys are presented to demonstrate the potential of this sample preparation technique. [ABSTRACT FROM AUTHOR]

Hydrogen diffusion through the oxide grown on Zr alloys by aqueous corrosion processes plays a critical role in determining the rate of hydrogen pickup (HPU) which can result in embrittlement of fuel cladding and limit the burnup of the nuclear fuel it encapsulates. Mapping the hydrogen/deuterium distributions in these oxide layers, especially in the barrier layer close to the metal/oxide interface, is a powerful way to understand the mechanism of both oxidation and hydrogen pickup. Here we have characterised by high-resolution SIMS analysis the deuterium distribution in oxide layers on a series of Zr alloys, including autoclave-oxidised Zircaloy-4, Zr-1Nb and Zr-2.5Nb alloys, and in-flux and out-of-flux corroded Zr-2.5Nb samples. Pre-transition Zircaloy-4 samples show a high deuterium trapping ratio in the oxide and a higher diffusion coefficient than in oxides on the Nb-containing samples. Neutron irradiation increases the deuterium diffusion coefficient, the deuterium concentration in the oxide and the pickup fraction in Zr-2.5 Nb samples. Comparative NanoSIMS and EDX/SEM analysis demonstrates that the deuterium is not preferentially trapped at second phase particles in the oxides on any of the alloys studied, but there is direct evidence for trapping at the surfaces of small oxide cracks especially in Zircaloy-4 samples. The high resolution mapping of these hot-spots in 3D can provide unique information on the mechanisms of hydrogen uptake, and suggests that the development of interconnected porosity in the oxide may be the critical rate-determining mechanism that controls HPU in the aqueous corrosion of zirconium alloys in water-cooled reactors. Image, graphical abstract [ABSTRACT FROM AUTHOR]

We have investigated the microstructural and crystallographic evolution of nanocrystalline zirconia under heavy ion irradiation using in-situ transmission electron microscopy (TEM) and have studied the atomic configurations of defect clusters using aberration-corrected scanning transmission electron microscopy (STEM). Under heavy ion irradiation the monoclinic-ZrO 2 is observed to transform into cubic phase, stabilised by the strain induced by irradiation-induced defect clusters. We suggest that the monoclinic-to-cubic transformation is martensitic in nature with an orientation relationship identified to be (100) m ∥(100) c and [001] m ∥[001] c. By increasing the damage dose, both the formation of voids and irradiation-induced grain growth were observed. A model for the formation of voids is proposed, taking defect interactions into consideration. The study has also demonstrated that high resolution orientation mapping by transmission Kikuchi diffraction (TKD) combined with in-situ irradiation in a TEM is a powerful method to probe the mechanisms controlling irradiation-induced processes, including grain boundary migration, phase transformations and texture evolution. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Terahertz single-photon detection and imaging have attracted full attention recently. Nonlinear optical frequency up-conversion is a promising technique that can be expected to satisfy this demand thanks to its high sensitivity and fast response. In this paper, theoretical analysis and numerical calculations based on the organic salt 4′-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystal were performed to show that the optimization of the detection of terahertz is different from that of the generation of terahertz, including the use of difference-frequency generation (DFG) technique, the larger thickness of the crystal, and especially the selection of the polarization direction of the pumping laser. For two different polarization configurations, the photons of the up-converted signal light both can be amplified compared with the number of incident terahertz photons under some optimal designs of the nonlinear frequency conversion process. Therefore, terahertz single-photon detection can be realized with single-photon detectors (SPDs) or even possibly with ordinary avalanche photodiodes (APDs). Furthermore, for terahertz single-photon imaging, the frequency up-conversion with the pumping laser polarized along b-axis of DAST crystal has a better performance, which is rarely used in terahertz generation. [ABSTRACT FROM AUTHOR]

When the impedance-based stability criterion is used to analyze the stability of a three-phase inverter-grid system, the impedance of the grid-connected inverter has to be known. This article proposes an inverter impedance measurement method in stationary frame using the off-shelf frequency response analyzer (FRA). In small-signal representation, inverter impedance can be represented by the equivalent admittance, which enables accurate representation of the inverter frequency response. The admittance expression in the stationary frame contains frequency coupling components. These components include the response current or voltage at frequency different from the perturbation frequency. But, the existing FRA only measures the response current and voltage having the same frequency as the perturbation frequency. The proposed method constructs three intermediate variables to overcome this limitation. These variables can be obtained by the measured data from FRA. Then the equivalent admittance under different grid impedances can be expressed by them. Since the equivalent admittance considers the frequency coupling effect, accurate stability analysis of the inverter-grid system can be guaranteed. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed impedance measurement method. [ABSTRACT FROM AUTHOR]

High afterpulse probability and the consequent long dead time of free-running InGaAs(P) single-photon detectors have long been the limiting factors to their practical applications. Here we present a free-running InGaAsP single-photon detector for 1.06 μm wavelength with ultra-low dead time and afterpulse probability. With the optimized active-quenching circuit and packaging, the avalanche pulse discrimination level is down to 2.4 mV, and the full-width at half-maximum of the avalanche pulse is as short as 500 ps, which greatly lessens afterpulsing effects. As a result, the dead time of the detector is as low as 35 ns, comparable to free-running silicon detectors, with a low afterpulse probability of 11.6% at 10% detection efficiency, 242 K. The proposed detector provides a high-performance, small-sized, low-power approach to single-photon detection for practical applications such as light detection and ranging and free-space quantum key distribution systems. [ABSTRACT FROM AUTHOR]

Oxidation of metals by water generates hydrogen which can enter the solid causing serious degradation of its mechanical properties and may also influence the corrosion rate. The present work focuses on hydrogen pickup during the corrosion of zirconium alloys in an aqueous environment. Transmission electron microscopy using Fresnel imaging on three different samples of oxidized Zr has been used to study the type, distribution, concentration and connectivity of nano-porosity as a function of depth through the oxide layer. Extensive interconnected nano-pipes are found in the non-protective outer part of the oxide, while in the protective barrier layer closer to the metal-oxide interface, continuous nano-pipes turn into individual nano-pores. Ab initio calculations show that molecular hydrogen is formed spontaneously by the reaction of water with oxygen vacancies in zirconium oxide. Molecular dynamics simulations reveal that these H 2 molecules can diffuse rapidly through nano-pores and nano-pipes as small as 0.5 nm in the oxide layer. Calculations demonstrate that molecular hydrogen dissociates spontaneously on surfaces of suboxides found experimentally at the metal-oxide interface. Oxygen vacancies in ZrO enable the ingress and diffusion of H atoms with an energy barrier of approximately 65 kJ/mol. Further diffusion of hydrogen through oxygen-saturated α -Zr metal is fast, leading to the formation of thermodynamically stable zirconium hydrides. Thus, formation and diffusion of molecular hydrogen through nano-pores in the bulk oxide and ingress of H atoms via suboxides is a possible mechanism of hydrogen pickup in any metal or alloy covered by an oxide scale that contains nano-porosity. Image 1 [ABSTRACT FROM AUTHOR]

Displacive transformations have been widely reported in metals, alloys and ceramics, but rarely reported to be important in the aqueous corrosion of alloys. We report here our analysis of the formation of the hexagonal-ZrO suboxide during the aqueous corrosion of α-Zr alloys and propose this to be a paraequilibrium displacive transformation with the rate controlled by oxygen diffusion. Two orientation relationships were identified between α-Zr and hexagonal-ZrO, (0002) α − Z r ∥ (1 ¯ 011) h − Z r O and [ 2 ¯ 110 ] α − Z r ∥ [ 10 1 ¯ 2 ] h − Z r O or (0002) α − Z r ∥ (22 4 ¯ 1 ¯) h − Z r O and [ 2 ¯ 110 ] α − Z r ∥ [ 1 1 ¯ 01 ] h − Z r O , with the first one more commonly observed. No specific orientation relationships between either hexagonal-ZrO and monoclinic-ZrO 2 or α-Zr and monoclinic-ZrO 2 were identified, which suggests that the formation of often-reported bulk oxide texture during aqueous corrosion is not related directly to the texture of the metallic substrate. These results provide a guideline for understanding the mechanisms of crystallographic evolution during oxide growth on commercial zirconium alloys, and also demonstrate the capability of transmission Kikuchi diffraction to investigate orientation relationships in nano-scale materials. Image 1 [ABSTRACT FROM AUTHOR]

• We have discussed the mechanisms influencing the depth resolution in 'on-axis' TKD. • Signals contributing to detectable Kikuchi bands in TKD originate from a volume of finite thickness (∼λ TDS) next to the bottom foil surface. • This existing surface sensitivity of TKD analysis can lead to the observation of different grain structures when opposite sides of a nano-crystalline foil are facing the incident electron beam. • A guideline for suitable sample thickness is suggested in order to achieve clear and indexable Kikuchi patterns for TKD analysis. In this paper, we have analyzed the depth resolution that can be achieved by on-axis transmission Kikuchi diffraction (TKD) using a Zr–Nb alloy. The results indicate that the signals contributing to detectable Kikuchi bands originate from a depth of approximately the mean free path of thermal diffuse scattering (λ TDS) from the bottom surface of a thin foil sample. This existing surface sensitivity can thus lead to the observation of different grain structures when opposite sides of a nano-crystalline foil are facing the incident electron beam. These results also provide a guideline for the ideal sample thickness for TKD analysis of ≤ 6λ TDS , or 21 times the elastic scattering mean free path (λ MFP) for samples of high crystal symmetry. For samples of lower symmetry, a smaller thickness ≤ 3λ TDS , or ≤ 10λ MFP is suggested. [ABSTRACT FROM AUTHOR]

• The limitation of the recent control methods (FCIN and FCOUT) are analyzed by analytical expressions. • The proposed method greatly improves the system stability, since it overcomes the limitation that the recent control methods do not consider the duty cycle perturbations. • The proposed method is simple and readily realized in the traditional control structure because it constructs an integrator and a high pass filter path outside the PLL. The interaction between the inverter and the grid in weak grids may produce resonances that lead to reduced power quality and instability concern. The recently proposed control methods based on eliminating disturbances in the control loop avoid the challenging control parameter design faced by the existing stability-enhancing control methods. They are effective to overcome the instability concern, but may not be able to maintain stable operation of the system in certain situations. Moreover, they affect the steady-state output current of the system under the fluctuation of the grid. This paper proposes a phase feed-forward method in the dq-frame to overcome the problems encountered by these control methods, such as duty cycle perturbation and grid phase jump. The proposed method constructs an integrator and a high pass filter path outside the PLL. It is simple and readily realized in the traditional control structure. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]

Abstract The full lattice strain tensor and lattice rotations induced by a dislocation in pure tungsten were mapped using high-resolution transmission Kikuchi diffraction (HR-TKD) in a SEM. The HR-TKD measurement agrees very well with a forward calculation using an elastically isotropic model of the dislocation and its Burgers vector. Our results demonstrate that the spatial and angular resolution of HR-TKD in SEM is sufficiently high to resolve the details of lattice distortions near individual dislocations. This capability opens a number of new interesting opportunities, for example determining the Burgers vector of an unknown dislocation in a fast and straightforward way. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract The mitigating effect introduced by intergranular Cr carbides on the stress corrosion cracking propagation of a cold-worked Alloy 600 has been firstly examined through high-resolution 3-dimensional (3D) sequential sectioning. High-resolution transmission electron microscope (TEM) and transmission Kikuchi diffraction (TKD) are used to reveal the underlying mechanisms contributing to the mitigating effect. Previously reported mechanisms contributing to the increased stress corrosion cracking resistance are evaluated and discussed. A new mechanism based on grain boundary migration inhibition and crack path deviation is proposed. Graphical abstract Image 1 Highlights • Mitigating effect of intergranular carbides on SCC was observed in 3D. • Cold woking-induced preferential deformation around intergranular carbides was observed via TKD. • Previously reported mechanisms contributing to the mitigating effect were evaluated and discussed. • A new mechanism based on grain boundary migration inhibition and crack path deviation was proposed. [ABSTRACT FROM AUTHOR]

Optical projection tomography (OPT) is an advanced three-dimensional (3D) imaging technology, which uses the filtered backprojection (FBP) algorithm to recover the 3D volume with sufficient number of projections. As to in vivo imaging, it is urgent to reduce the number of projections because the acquisition time could be minimized. However, reconstructing from undersampled OPT data can lead to artifacts and the decline in image quality. The simultaneous iterative reconstruction technique (SIRT) is introduced to remove artifacts and improve the image quality. The image qualities reconstructed from FBP and SIRT separately are compared, and the structural similarity and peak signal-to-noise ratio are calculated. Through simulated phantoms and OPT data of in vivo zebrafish embryo, SIRT consistently outperforms FBP in terms of reduced artifacts and enhanced image contrast especially when the projection numbers are reduced. SIRT method can provide high-quality reconstruction with 50 or fewer projections, thereby significantly reducing the minimum acquisition time and light dose while maintaining reconstruction quality. Through optimization and GPU acceleration, the SIRT algorithm can converge faster so as to reduce the image processing time. To our knowledge, this is the first time one SIRT algorithm is used for reconstruction of sparse OPT data. The experimental results show that SIRT algorithm outperform FBP especially when the number of projections is reduced. In addition, SIRT performs better in the preservation of vascular signal, which is significant for the monitoring of angiogenesis. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) have been widely explored as additives to improve the performance of lithium–sulfur (Li–S) batteries, however, the design of highly catalytic and in‐depth knowledge of the structure–activity relationship of SACs remains a huge challenge. Herein, electron redistribution of the Co site by introducing the S atom to replace the N atom in the first coordination shell is theoretically predicted to enhance the anchoring capability of lithium polysulfides (LiPSs) and simultaneously facilitate the redox process of Li–S batteries, due to the strengthened d‐p orbital hybridization between sulfur species and SACs compared with the traditional CoN4 architecture. Enlightened by theoretical analysis, asymmetric (N, S) coordinated Co single atoms embedded on N, S‐doped hierarchically porous carbon (S‐Co‐SACs/NSC) is precisely designed and constructed as a high‐efficiency fixity and catalyst for Li–S batteries. Therefore, the battery with S@S‐Co‐SACs/NSC cathode exhibits high areal capacity and cycling stability. This work highlights the vital function of the electronic structures of SACs in promoting the practical application of Li–S batteries. [ABSTRACT FROM AUTHOR]

A beam-profile monitor has been constructed based on a two-dimensional cross-connected-pixels anode and a 128-channel picoammeter system. It can provide the total beam current, as well as the current projections in the x- and y-directions with a spatial resolution of ∼1 mm. It is suitable for diagnosis of low-energy charged-particle beams ranging from subpicoamperes to nanoamperes, e.g., the ion beams extracted from an electron beam ion source. [ABSTRACT FROM AUTHOR]

Z-type hexagonal ferrite ultrafine powders with chemical formulations of (Ba x Sr 1-x ) 3 Co 2 Fe 24 O 41 (x varied from 0.0 to 1.0) have been synthesized by a sol-gel auto-combustion technique. The average particle sizes of the synthesized powders ranged from 2 to 5 μm. The partial substitution of Ba 2+ by Sr 2+ led to the shrinkage of the crystal lattices and resulted in changes in the magnetic sub-lattices, which tailored the static and dynamic magnetic properties of the as-synthesized powders. As the substitution ratio of Ba 2+ by Sr 2+ , the saturation magnetization of the synthesized powders almost consistently increased from 43.3 to 56.1 emu/g, while the real part of permeability approached to a relatively high value about 2.2 owing to the balance of the saturation magnetization and magnetic anisotropy field. [ABSTRACT FROM AUTHOR]

The rapid chemical co-precipitation method is supposed to be a stable way to synthesize high quality cubic yttrium iron garnet (YIG) nanopowders. In this paper, focusing on clarifying its formation mechanism, the thermal behaviors and the elemental distributions of the chemical co-precipitated precursors have been analyzed by simultaneous differential scanning calorimetry plus thermal gravimetric analysis (DSC-TGA) and energy disperse spectroscopy (EDS) mapping technique on a transmission electronic microscope. The results indicated that the homogeneity of Y and Fe elemental distributions in the precursor powders determines the process through which the cubic YIG phase would form: one experiences the intermediate tetragonal YIG phase; the other takes YFeO 3 as the intermediate phase. The homogenous distributions of Y and Fe elements in the precursor powders at the scale below 50 nm forms the intermediate tetragonal YIG phase rather than YFeO 3 , which leads to reduction of the formation temperature for synthesizing the single phase YIG. The obtained YIG nanopowders with the average particle size below 100 nm show excellent magnetic properties with saturation magnetization of 26 emu/g and coercive field of 45 Oe. This clear formation mechanism of YIG nanopowders is suitable for optimizing the processing conditions for the chemical precipitation synthesis of YIG nanopowders at large scale. [ABSTRACT FROM AUTHOR]

304 stainless steel is known to be metastable as the austenite phase can transform into martensite under deformation. In this work, both ex-situ and in-situ transmission electron microscopy (TEM) characterization were used to investigate the mechanisms of the deformation-induced transformation at room temperature. The ex-situ tensile tests were conducted at a strain rate of 10 −3 s −1 until rupture, followed by TEM and X-Ray Diffraction (XRD). Samples were also interrupted at strains of 7%, 18%, and 30% with the goal of investigating the intermediate microstructure. In addition, tensile tests were conducted in-situ in a TEM at 25 °C using a special straining-stage with the goal of capturing the nucleation and growth of the martensitic phase as it develops under deformation. The formation of stacking faults and the subsequent formation of ε-martensite (hcp) through their overlapping/bundling was captured in-situ, confirming the role played by Stacking Faults (SFs) as intermediate step during the transformation from γ-austenite to ε-martensite. Direct transformation of γ-austenite (fcc) to α’-martensite (bcc) was also captured upon straining and characterized. Such unique in-situ observations showcase how in-situ straining in a TEM, as a small scale tensile technique, is a powerful technique to visualize and investigate the mechanisms of deformation induced phase transformations. [ABSTRACT FROM AUTHOR]

The traditional username/password or PIN based authentication scheme, which still remains the most popular form of authentication, has been proved insecure, unmemorable and vulnerable to guessing, dictionary attack, key-logger, shoulder-surfing and social engineering. Based on this, a large number of new alternative methods have recently been proposed. However, most of them rely on users being able to accurately recall complex and unmemorable information or using extra hardware (such as a USB Key), which makes authentication more difficult and confusing. In this paper, we propose a Digital Memories based user authentication scheme adopting homomorphic encryption and a public key encryption design which can protect users’ privacy effectively, prevent tracking and provide multi-level security in an Internet & IoT environment. Also, we prove the superior reliability and security of our scheme compared to other schemes and present a performance analysis and promising evaluation results. [ABSTRACT FROM AUTHOR]

In this work, two P-superfamily conotoxins, lt9a and lt9b, were purified and characterized from the crude venom of Conus litteratus . The amino acid sequences of lt9a and lt9b were determined by the Edman degradation method. It has been suggested that both lt9a and lt9b are produced from the precursor encoded by the gene Lt9.1 . During the conotoxin maturation process, different post-translational modifications occurred between lt9a and lt9b. Conotoxin lt9b was predicted to have two prolines that underwent hydroxylation and one glutamate that underwent carboxylation, while lt9a had no hydroxyproline and carboxyglutamate residue. The calculated mass weights of two P-superfamily conotoxins with three proposed disulfide bonds were confirmed by matrix-assisted laser desorption/ionization–time-of-flight (MALDI-TOF) mass spectrometry after considering corresponding post-translational modifications. These two conotoxins showed different effects on tetrodotoxin-sensitive sodium currents. Conotoxin lt9a (300 nM) resulted in marked slowing of the tetrodotoxin-sensitive sodium current decay, a notable increase in the peak current, and an alteration in reversal potential. However, lt9b inhibits tetrodotoxin-sensitive sodium currents, and the inhibition showed a concentration-dependent with the half maximal inhibitory concentration (IC50) value of 504.04 nM, but there were no change in the activation and inactivation kinetics of currents. To the best of our knowledge, this is the first investigation of two P-superfamily conotoxins identified to act on voltage-sensitive sodium channels with different modifications. [ABSTRACT FROM AUTHOR]

In this study, we have investigated the microstructure and mechanical properties of two refractory high entropy alloys (RHEAs), Ti-V-Cr5-Nb-Ta and Ti-V-Cr-Nb-Ta, in their as-cast and heat-treated conditions. Both alloys show almost single-phase BCC structure, while different size and volume fraction of secondary phases were formed after homogenisation heat treatment. The major secondary phase was indexed as a complex C15 Laves structure with a composition of (Ti, Ta)(V, Cr, Nb) 2. The nanoindentation mapping indicates C15 Laves phase is very hard and brittle, performing a homogenisation heat treatment leads to an improved hardness in both alloys. The correlations between hardness changes and microstructural evolutions after homogenisation heat treatment are also discussed. [Display omitted] • Microstructure of two RHEAs were determined in different heat-treated conditions. • The precipitates show a substitutional C15 structure close to (Ti, Ta)(V, Cr, Nb) 2. • The hardness of C15 Laves phase is ∼2 times that of the BCC matrix. • A method is proposed to introduce a fine dispersion of precipitates in the RHEA. [ABSTRACT FROM AUTHOR]

A fast active-quenching circuit (FAQC) based on SiGe Hetero-junction Bipolar Transistor (HBT) and InGaP/GaAs HBT integrated circuits is designed for use with free-running single-photon avalanche diodes (SPADs). The performances of both InGaAsP/InP SPAD and InGaAs/InP SPAD are tested. Results show that the typical avalanche duration using the FAQC is 1.6 ns, and the total afterpulse probability is lower than 10% when the hold-off time is above 1 \mu \texts at 1.5 V excess bias or 10 \mu \texts at 3.0 V excess bias. This result is comparable to recently developed negative-feedback avalanche diodes. The FAQC is based on commercially available integrated circuits and can be used with typical SPADs, providing a low-cost approach to build a free-running single-photon detector. [ABSTRACT FROM PUBLISHER]

A simple statistical method is proposed for afterpulse probability measurement in high-speed single-photon detectors. The method is based on in-laser-period counting without the support of time-correlated information or delay adjustment, and is readily implemented with commercially available logic devices. We present comparisons among the proposed method and commonly used methods which use the time-correlated single-photon counter or the gated counter, based on a 1.25-GHz gated infrared single-photon detector. Results show that this in-laser-period counting method has similar accuracy to the commonly used methods with extra simplicity, robustness, and faster measuring speed. [ABSTRACT FROM AUTHOR]

To effectively reuse waste rubber and reduce secondary pollution, a microwave-assisted in situ surface modification and semi-devulcanization route has been developed to fabricate magnetic rubber composites. The composites use waste rubber powders and ultrafine barium ferrite powders as starting materials without additional additives. Taking advantage of the microwave absorption capabilities of the barium ferrite powders and filling materials that exist in waste rubber, both the semi-devulcanization of the waste rubber powder and surface modification of barium ferrite powder have been simultaneously achieved under microwave irradiation. Thus, the phase compatibilities between barium ferrite and the rubber matrix are effectively improved, resulting in a low-cost fabrication of flexible magnetic composites with good ferromagnetic properties. The presented microwave assisted technique may also offer a novel path to design and produce organic–inorganic nano-composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • N V guarentee the evolution of O 2 to H 2 O 2 as O 2 exclusive adsorption sites, which improves the efficiency of photopurification work. • –CN, substitutes for hydrogens in primary amines, offer the opportunity for controlling reaction selectivity by inhibiting H 2 O 2 randomly decomposing to •OH. • The steric hindrance effect between N3C and SO induced by –CN and N V prevents H 2 O 2 reducing to •OH enabling the stable presence of SO. The key of photopurification, a bran-new technique for substance purification, is selective mineralization by surface modification of photocatalyst. CN/N V -PCN, nitrogen vacancies (N V) and cyano groups (–CN) co-modified polymeric carbon nitride (PCN), selectively photomineralize benzaldehyde (BZ) in industrial styrene oxide (SO) production solution. N V , special O 2 adsorption sites, guarantee the activation of O 2 to H 2 O 2. –CN, substitutes for hydrogens in terminal amines (–NH 2), inhibit H 2 O 2 randomly decomposing to •OH on –NH 2 sites. N V and –CN adjust the electronic distribution on triazine ring and H to reinforce π-π interaction and O···H N bond between PCN and SO, narrowing the space between benzene ring and N3C site, in which the steric hindrance effect hinders H 2 O 2 reducing to •OH by e- on N3C site. •OH can only produce at the adsorption sites of BZ, which results the selective mineralization of BZ. This work provides not only a modification method of PCN for selective oxidation reaction, but also a bran-new technique for removing homogeneous trace impurities in natural or industrial products. [ABSTRACT FROM AUTHOR]

The carbonized layers formed on the surfaces of the barium haxe-ferrite nanoparticles based on the heat treatment of barium haxe-ferrite/polyaniline nano-composites. The surface carbonized layers consisted of the amorphous carbon with the thicknesses ranging from 10 to 30 nm. The existence of the surface carbonized layers on the magnetic ferrite nanoparticles could alter the interfacial and dielectric loss. By changing the thickness of the carbonized layer, the impendence match was refined and the fine microwave absorbing properties were achieved. The result indicated that the design and optimization of sophisticated interfacial structures would provide a potential way to develop multi-phase EM wave absorbers with better performances. [ABSTRACT FROM AUTHOR]

Near-inertial oscillations in the northern South China Sea, close to the Xisha Islands, during the passage of typhoon Conson, were investigated using 52-day observational data and a damped slab model. Using spectral analyses, we found that these near-inertial oscillations were dominated by clockwise components. The observed, as well as simulated, inertial currents matched well before and after the passage of the typhoon, which revealed that significantly enhanced oscillations were induced by the typhoon. They have a peak frequency of 0.0237 cycles per hour, which is 2% lower than the local inertial frequency, meaning a red-shift phenomenon exists, even in shallow water. The red-shift might be attributed to the background negative vorticity. Additionally, we found that the barotropic near-inertial currents were more significant after the passage of the typhoon. The position of the maximum intensity of near-inertial current shear with a period of 20.8 h was found to propagate upward slowly with time before the passage of the typhoon. [ABSTRACT FROM PUBLISHER]

Barium hexa-ferrite (BaFe 12 O 19 )/polyaniline (PANI) core–shell nano-composites have been fabricated by an in situ polymerization and the shell thickness of PANI layers were tuned by increasing the content of the starting monomer and evaluated by combination TG and TEM results. Based on these, the influences of the shell thicknesses on the properties of the as-synthesized nano-composites have been investigated. The results indicated that the electric and magnetic characteristics of the synthesized nano-composites have been tuned by altering the shell thickness. With refining impedance match and taking advantages of conductance loss, magnetic resonance loss and interfacial loss, the microwave absorbing properties of the synthesized composites have been enhanced. Both the microwave absorbing efficiency and frequency range changed as the shell thickness increased. The optimized core–shell nano-composites with the shell layer of 30–40 nm demonstrated the best microwave absorbing properties with the maximum absorption −28 dB at 12.8 GHz and the −10 dB absorption bandwidth of 3.8 GHz (11.8 GHz–15.6 GHz) as the thickness of the absorbing layer was as thin as 2.0 mm. [ABSTRACT FROM AUTHOR]

To synthesize high quality barium hexa-ferrite nano powders, an ultrasonic-assisted co-precipitation method has been used and the influences of the ultrasonic technique on the particle morphologies and magnetic properties of the synthesized barium hexa-ferrite nano powders have been investigated. The results indicated that the introduction of ultrasonic energy into the co-precipitation process promoted the composition homogeneities of the co-precipitated precursors, minished their particle sizes, and exerted the additional surface barriers between the particles, which influenced both the phase formation and particle growth-up processes during the subsequent heating treatment and altered the particle sizes, size distributions and particle shapes of the final synthesized powders. The average particle sizes of the synthesized nano powders dramatically decreased from 210 nm to about 100 nm as the inputting ultrasonic power increased, while the size distribution became increasingly uniform except for a few of large particles existed as the inputting power approached to a high value. The magnetization at 1.4 T of the as-synthesized barium hexa-ferrite dramatically increased and approached to the highest value of 57.9 emu/g due to the elimination of multi-domain particles, the alleviation of particle adhesion and the evolution of particle shape from flake to quasi-sphere as well as the uniform particle size distribution as the ultrasonic assistance was employed, and slightly decreased because of the coarsening in particle sizes. [ABSTRACT FROM AUTHOR]

Luminescent microspheres [poly(St-co-VBA)–Tb] were easily fabricated from poly(St-co-VBA) and aqueous Tb(iii) chloride solution in the presence of triethylamine. The negative charges on the surface of microspheres coordinated with Tb3+, resulting in strong photoluminescence. Such terbium compounds were firmly stabilized in the microspheres. Various methods, including TGA, TEM, SEM-EDS, ICP-MS, EPR, SEM, FT-IR, fluorescence spectrophotometry and laser scanning confocal fluorescence microscopy, were used to characterize the resultant polystyrene composite microspheres. [ABSTRACT FROM AUTHOR]

Wood is an attractive and inherently sustainable alternative to many conventional materials. Recent research on improving wood mechanical strength emphasizes wood densification through the partial removal of lignin and hemicelluloses, therefore the chemical and physical properties of delignified and densified wood require further investigation. In this study, poplar wood samples were subjected to alkali and maleic acid hydrotropic delignification with varying degrees of lignin and hemicellulose removal followed by hot pressing, and the microstructure, chemical properties, and dimensional stability of densified wood through delignification were evaluated. The results showed that the complete wood cell collapse was observed near the surface of all the delignified wood blocks, as well as some micro-cracks in the cell walls. The chemical analysis indicated that delignification occurred mainly near the surface of the wood blocks and enhanced hydrogen bonding among the aligned cellulose fibers. For dimensional stability, the set recovery decreased with the increase in alkali dosage, and the considerable fixation of compressive deformation was obtained by a post-densification hydrothermal treatment at 180 °C. These results have demonstrated that the densified wood with delignification can be easily fabricated using the proposed method, and the densified wood exhibited great potential to be used as a sustainable material. [ABSTRACT FROM AUTHOR]

Animal waste is a valuable resource, which can add organic matter, nitrogen, phosphorous and potassium as well as other nutrients needed for plant growth when it is used in the agricultural field. When applied to an agricultural field, infectious agents or pathogenic organisms in the animal waste are usually retained in the soil. At the same time, surfactants are popularly utilized in pesticide applications to aid pesticide solubility and mobility. Consequently, the retained pathogenic strains might be flushed out of the soil matrices with a possibility of contaminating the groundwater. In this research, we investigated desorption of E. coli O157:H7 pre-deposited in silica sand and its subsequent release and transport in the presence of rhamnolipid biosurfactant in unsaturated laboratory columns. Based on the experimental observations, it was discovered that retained E. coli O157:H7 was released during flushing with rhamnolipid biosurfactant solutions. E. coli O157:H7 release rate coefficient increased both with the increase of rhamnolipid biosurfactant concentration and the increase of water saturation. With the increase of rhamnolipid biosurfactant concentration, the air-water surface tension decreased. With the increase of water saturation, the air-water interfacial area decreased. Both the decreased air-water surface tension and air-water interfacial area favored E. coli O157:H7 release. Increase of E. coli O157:H7 release rate coefficient with the decrease of air-water surface tension was more pronounced for low air-water interfacial area (i.e., high water saturation). Similarly, increase of E. coli O157:H7 release rate coefficient with the decrease of air-water interfacial area was more pronounced for low air-water surface tension (i.e., high rhamnolipid biosurfactant concentration). E. coli O157:H7 retention in unsaturated systems was found to be controlled by the capillary force, which was greatly impacted by water saturation and air-water surface tension. Increase of water saturation and rhamnolipid biosurfactant concentration both contributed to the decrease of the capillary force, resulting in increased E. coli O157:H7 release rate. [ABSTRACT FROM AUTHOR]

Neosinocalamus affinis Keng is widely grown in south-western China for pulp and paper production. Rapid assessment of the chemical properties of N. affinis is necessary for both bamboo breeding and industrial utilization. This study was performed to investigate the abilities of Fourier transform near-infrared spectroscopy in the diffuse reflectance mode (FT-NIR-DR) and Fourier transform infrared attenuated total reflectance (FT-IR-ATR) spectroscopy to predict the contents of holocellulose, α-cellulose, Klason lignin, and NaOH extractives in N. affinis. Partial least squares regression models based on the raw and preprocessed spectra, including multiplicative scatter correction (MSC) and Savitzky-Golay 1st and 2nd derivative spectra, were developed for the chemical components of bamboo. The NIR-based calibrations displayed better performance than those using FT-IR-ATR spectra. The best calibrations developed by both methods for properties all had satisfactory correlations, with coefficient of determination (R2c) values ranging from 0.81 (Klason lignin by FT-IR and MSC) to 0.98 (α-cellulose by FT-NIR and 2nd derivative), and root mean standard error of calibration between 0.50 and 1.47%. When applied to prediction sets, the correlations were good, with R2p above 0.68. The results demonstrate that both spectroscopic methods, combined with chemometric strategies, could rapidly predict the chemical composition of bamboo. [ABSTRACT FROM AUTHOR]

Abstract: The vertical structure of current field in the northern South China Sea affected by the passage of Typhoon Pabuk is investigated using the observational data. The strong near-bottom current which has a duration of less than 1day is observed twice whereas such a current is almost missing at some intermediate layers. It is suggested by the power spectral density that the typhoon strengthens the near-inertial current which is the most significant in the upper layer and the weakest in the middle layer after the passage of Pabuk. The wave-number rotary spectrum is calculated to study the characteristics of the energy which the typhoon injects into the ocean, and it is suggested that the strong near-bottom current may be supported by the transport of energy by the near-inertial waves induced by typhoon, thus the pressure gradients might be established through the continental slope and induce the strong near-bottom current. [Copyright &y& Elsevier]

Abstract: Capsella bursa-pastoris, a winter annual weed in the mustard family, can not be controlled by tribenuron after the herbicide has been continuously used for several years. The resistant biotype Lz-R was the generation of a population collected from Liangzhu, a place where tribenuron had been used for more than 15 consecutive years. To confirm and characterize the resistance of C. bursa-pastoris to tribenuron, whole-plant bioassays were conducted in the greenhouse. The results of whole-plant bioassays revealed that Lz-R was highly resistant to tribenuron with the resistance index (GR50 Lz-R)/(GR50 Lz-S) up to 236.6. To investigate the molecular basis of resistance in C. bursa-pastoris, the acetolactate synthase (ALS) genes were sequenced and compared between susceptible and resistant biotypes. Analysis of the nucleotide and deduced amino acid sequences between the biotypes indicated that one substitution had occurred in Domain A, cytosine by thymine (CCT to TCT) at position 197, that led to a change of the amino acid proline in the susceptible to serine in the Lz-R. [Copyright &y& Elsevier]

This research investigated the impact of particle size on colloid retention in water unsaturated porous media using column experiments. Three different-sized silica sols were used as the model colloids in this research. Colloid column transport experiments were conducted under steady-state water flow conditions with effective water saturation ranging from 0.2 to 1.0 in two different-sized porous media. Colloid transport was described by the mobile-immobile two-region transport model. Under saturated conditions, minimal colloids were retained in the porous media. Under water unsaturated conditions, the observations were closely related to system water saturation. At high water saturation (i.e., effective water saturation of 0.80), colloid retention decreased with the increase of colloid size. At intermediate water saturation (i.e., effective water saturation of 0.50), the effect of particle size on colloid retention was not obvious. At low water saturation (i.e., effective water saturation of 0.20), colloid retention in the porous media increased with the increase of particle size. Under constant chemical conditions, colloid retention in the unsaturated porous media was believed to be determined by a balanced effect of shear forces and physical constraints, which was a function of both particle size and water saturation. [ABSTRACT FROM AUTHOR]