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The black shale of the Upper Ordovician and Lower Silurian is a significant target for shale gas exploration in the Southern Sichuan Basin. In this study, we introduced a lithofacies classification for shale based on rock mineral composition. Because the pore structure of gas shale reservoirs are complex and greatly affect the gas storage and transport in shale, four different methods of low-pressure nitrogen gas adsorption, high-pressure mercury intrusion, scanning electron microscopy (SEM) and gas expansion methods were used to investigate the reservoir pore structure and storage space. Combined with X-ray diffraction, total organic matter content (TOC), gas content, methane adsorption, porosity and permeability and wireline data, the key factors that affect shale gas content and storage of shale gas were analyzed. According to our shale classification, three main lithofacies, i.e., calcareous mudstone (CM), high calcareous mixed mudstone (HCMM) and low calcareous mixed mudstone (LCMM), were identified in our study area. The experiment indicates that the shale has a high TOC, thermal maturity and gas content. The methane adsorption isotherms show that the sorbed gas content has a positive correlation with TOC. Difference of TOC between the three is small. Nitrogen adsorption indicates that mesopores dominate the shale pore composition and organic matter is the main source of mesopores. Mercury injection shows that the macropore volume accounts for approximately 14–22% of the total pore volume. No obvious pore structure differences were found for different lithofacies. However, taking the porosity into consideration, LCMM has the largest macropore volume. The SEM observations revealed that organic matter pores, interparticle pores and intraparticle pores are the main pore types. Interparticle pores mainly develop in LCMM which has a relatively high quartz and low carbonate content, it may be the major reason for high porosity, high macropore volume, and high free gas content of LCMM. Free gas and absorbed gas are the major storage form of shale gas. Given similar temperature and pressure conditions, the total organic matter content is the major factor that affects the adsorbed gas content. Therefore, with high free gas and adsorbed gas content, LCMMs with high total organic matter contents would be the most favorable type of lithofacies in this region. [ABSTRACT FROM AUTHOR]

• Degradation mechanism of biotite in manufactured sand on concrete performance was presented. • An empirical formula of compressive strength for different biotite content was presented. • FEM-DEM coupling program was developed to optimize biotite separation process. Harmful components such as biotite in fine aggregates formed by natural rock crushing need to be rigorously assessed and effectively separated to reduce their potential damage to concrete structures. In this study, magnetic separation was used to remove excess biotite from manufactured sand and to realize the upgrade of manufactured sand, and a series of laboratory tests were carried out to study the influences of biotite content on the compressive strength and splitting strength of concrete. Experimental results show that the magnetic separation method can effectively reduce the biotite content in concrete from 10 % to 2 %, thus improving the mechanical properties of concrete. Through microscopic characterization, we found that the surface layer of biotite had a strong bonding effect with the early hydration product. This bonding effect contributes to the early strength of concrete, leading to a small difference in the strength values of manufactured sand concrete with different biotite contents. With increasing curing age, the strength contribution caused by this bonding effect gradually decreases. In addition, FEM-DEM coupling simulation was used to optimize the operation parameters and magnetic system structure of the magnetic separator to further achieve efficient separation of biotite from manufactured sand. Numerical prediction indicates that the dry magnetic separator has an extrusion magnetic system structure, which makes the magnetic induction and magnetic induction gradient at the guide disk higher and provides a much greater magnetic force than other competitive forces for biotite particles. To efficiently recover low-grade manufactured sand (low biotite content) from manufactured sand, the feed rate t , conveyor belt speed V and magnet-to-steel disk thickness ratio μ should be kept at 0.8 kg/s, 0.85 m/s and 3, respectively. This study can provide potential solutions and broad application value for the problem of manufactured sand with high biotite content in practical engineering. [ABSTRACT FROM AUTHOR]

A quickly kinetics for de-solvation of hydrate zinc ions benefits from the interaction between electron-donating group and water sheath of hydrated ions. Rich-cyano SEI (rc-SEI) for Zn anode was prepared by coating polyacrylonitrile (PAN) on zinc foil, which realizes low de-solvation activation energy (Ea) of hydrated ions (41.9 kJ mol−1 for rc-SEI@Zn and 63.7 kJ mol−1 for bare Zn). [Display omitted] • Cyano as electron-donating group can interact with sheath of hydrated ions. • Rich-cyano SEI (rc-SEI) reduces de-solvation activation energy of hydrated ions. • Rc-SEI contributes to dendrite-free deposition and high CE of zinc anode. • Rc-SEI improves the cycling performance of a full battery with lean zinc anodes. Aqueous zinc ion batteries (AZIBs) subject to severe sluggish electrodeposition process due to burdensome de-solvation of hydrate zinc ion (Zn(H 2 O) 6 2+→Zn2+) which leads to high overpotential, low utilization of zinc and high interface impedance. Here, an artificial solid electrolyte interphase (SEI) with rich electron-donating functional group (cyano group) is proposed for zinc anode to achieve favorable de-solvation process and deliver stable rechargeable AZIBs. The rich-cyano SEI (rc-SEI) can improve the de-solvation kinetics by formation interaction force between cyano group and water sheath of hydrated ions. The de-solvation activation energy (E a) of hydrated ions for rc-SEI@Zn is only 41.9 kJ mol−1, much lower than that of the bare Zn (63.7 kJ mol−1). The rc-SEI@Zn electrode realizes an enhanced CE of over 99.65 % within 550 cycles in Zn||Cu battery, a low polarization of less than 50 mV and ultra-long cycle life of over 1000 h in Zn||Zn battery. Moreover, Zn||MnO 2 full cell with rc-SEI@Zn anode shows 78.9% capacity retention after 690 cycles at 2C (218.2 mAh g−1 at 1st cycle and 172.1 mAh g−1 at 690th cycle). [ABSTRACT FROM AUTHOR]

[Display omitted] • Determination of Folpet and Phthalimide residues in tea by GC-MS/MS and GC-TOF HRMS. • The tea samples were heated at 80 °C for 30 min to convert all folpet to phthalimide. • Isotope internal standard and matrix-matched calibration were used. • The structure analysis of phthalimide and folpet were carried out. A novel and accurate method was developed for the determination of folpet and phthalimide residues in tea by solid-phase extraction (SPE) in combination with gas chromatography-tandem mass spectrometry (GC-MS/MS). According to related studies, folpet is easily degraded into phthalimide during sample pretreatment and GC injection. In this study, the conversion of all folpet to phthalimide prior to sample extraction and purification was proposed for the first time. An isotopic internal standard was used for quantification. The average recoveries ranged from 80.5 to 92.3% with RSD ≤7.2%. The limit of quantification for phthalimide was 5.0 µg/kg. The phthalimide content was accurately determined and converted to the folpet content to satisfy the requirements of regulations. The detected samples were further confirmed by gas chromatography time-of-flight high-resolution mass spectrometry (GC-TOF HRMS). This was a novel and particular attempt to resolve issues regarding folpet degradation, and satisfactory results were obtained. [ABSTRACT FROM AUTHOR]

For the first time, an efficient and sensitive analytical method based on liquid chromatography-quadrupole linear ion trap-tandem mass spectrometry (LC-QqLIT-MS/MS) was developed for the simultaneous determination of four paraben-type preservatives and three benzophenone-type ultraviolet light filters in both plant (Sargassum fusiforme, porphyra, kelp) and animal (hairtail, yellow croaker, shrimp) seafood. The samples were extracted in methanol by pressurized liquid extraction (PLE), and the extracts were then cleaned up by mixed-mode cationic exchange (MCX) solid-phase extraction cartridges. Both isotope-labeled internal standards and matrix-matched calibration standards were used to alleviate and correct for the matrix effects, and the limits of quantification (LOQs) were 10.0 μg kg −1 for all target compounds. The average recoveries were in the range of 80.6–107.8% at three spiked concentration levels (10, 50 and 100 μg kg −1 ) with relative standard deviations (RSDs) below 8.5%. The results suggest that very limited contamination of these seven emerging contaminants, mainly associated with PCPs, occurred in these common seafoods. [ABSTRACT FROM AUTHOR]

The modifications of implant surfaces are known to enhance their osseointegration potential. The objective of this study was to develop an efficient method of increasing surface roughness with a low energy pulsed ultraviolet (UV) laser. The UV laser treatment was applied on six titanium alloy (Ti-6Al-4V) disks with machined surfaces and a commercially available implant to offered a favorable surface topography for osseointegration. Three-dimensional confocal laser-scanning microscopy was used to observe the surface structures. Osteogenic cells were grown on the Ti-6Al-4V surfaces to assess their biocompatibility. The investigators found that the surface roughness obtained with the UV laser was similar to other SLA surfaces previously described. In addition, the UV laser-ablated surfaces exhibited significant texturing in surface topography and sustained osteogenic cells growth on the treated surfaces. [ABSTRACT FROM AUTHOR]

The modifications of implant surfaces are known to enhance their osseointegration potential. The objective of this study was to develop an efficient method of increasing surface roughness with a low energy pulsed ultraviolet (UV) laser. The UV laser treatment was applied on six titanium alloy (Ti–6Al–4V) disks with machined surfaces and a commercially available implant to offered a favorable surface topography for osseointegration. Three-dimensional confocal laser-scanning microscopy was used to observe the surface structures. Osteogenic cells were grown on the Ti–6Al–4V surfaces to assess their biocompatibility. The investigators found that the surface roughness obtained with the UV laser was similar to other SLA surfaces previously described. In addition, the UV laser-ablated surfaces exhibited significant texturing in surface topography and sustained osteogenic cells growth on the treated surfaces. [ABSTRACT FROM AUTHOR]

A method based on unscented Kalman filter parameter estimation is proposed for the design of lunar free-return trajectories. The method avoids calculating the Jacobian matrix and obtains large convergence ability compared with the common differential-correction method. Given that the initial estimate of the free-return trajectory is only required to be generated under the two-body Earth–spacecraft model, the difficulty of guessing a good initial estimate is greatly reduced. Through converting the original problem to a parameter estimation representation, the method is used to find the converged final solution that satisfies the constraints at injection, perilune, and Earth-entry interface under a high-fidelity gravitational model. In addition to its deceptively simplicity, the method proves to be quite effective through numerical examples in finding the solution to lunar free-return trajectories within a few iterations with great numerical accuracy. [ABSTRACT FROM AUTHOR]

This study addresses the previously unknown effects of algae blooms on the dynamics of phosphorus (P), iron (Fe) and sulfur (S) across a lacustrine sediment-water interface (SWI). A mesocosm experiment was conducted in-situ to investigate these effects based on two recently-developed diffusive gradients in thin-films techniques (DGT). Soluble P, Fe(II), and S(-II) exhibited similar changing trends in a water column subject to the algae addition. Peak concentrations appeared on day 7 of the 16-day experiment. The lowest Eh occurred at the experiment’s midway point indicating a strong algae degradation. A maximum increase in DGT-labile S appeared on day 8 near the SWI, while the DGT-labile P and Fe exhibited persistent increases almost to the end of experiment. Significantly positive correlations of labile P were observed switching from between labile Fe and labile S in sediments, suggesting a significant change in original Fe-coupled dynamics of P under algae decomposition. Apparent fluxes were calculated based on DGT profiles where a simultaneous release of P and S occurred from degraded algae, resulting in bidirectional diffusion fluxes from sediment to overlying water. In contrast, sediment acted as a major source of labile Fe due to added depth and apparently positive fluxes. [ABSTRACT FROM AUTHOR]

The increasing energy consumption and environmental concerns have driven the development of cost-effective, high-efficiency clean energy. Advanced functional nanomaterials and relevant nanotechnologies are playing a crucial role and showing promise in resolving some energy issues. In this view, we focus on recent advances of functional nanomaterials in clean energy applications, including solar energy conversion, water splitting, photodegradation, electrochemical energy conversion and storage, and thermoelectric conversion, which have attracted considerable interests in the regime of clean energy. [ABSTRACT FROM AUTHOR]

A hybrid analysis of the interfacial stresses near the free edges of piezoelectric unsymmetrical laminated plates under uniform extension is presented based on three-dimensional piezoelasticity. A state space equation for cross-ply asymmetric piezoelectric laminates is obtained by considering all the independent elastic and piezoelectric constants of the laminates. The equation satisfies the open-circuit electric, free boundary conditions at two opposite free edges. Using a transfer matrix and a recursive solution approach, a three-dimensional exact solution has been derived and this has been validated by comparing analytical results with those from finite element analyses. Discussion and comments on solutions obtained using the equations proposed are presented. Since all the continuity conditions across the interfaces between material layers are satisfied, the concentrations of interfacial stresses near free edge boundaries are determined precisely. The significant electromechanical influence of the boundary layer effect is found quantitatively. [ABSTRACT FROM AUTHOR]

Understanding the labile status of phosphorus (P) in sediments is crucial for managing a eutrophic lake, but it is hindered by lacking in situ data particularly on a catchment scale. In this study, we for the first time characterized in situ labile P in sediments with the Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique at a two-dimensional (2D), submillimeter resolution in a large eutrophic lake (Lake Taihu, China, with an area of 2338 km 2 ). The concentration of DGT-labile P in the sediment profiles showed strong variation mostly ranging from 0.01 to 0.35 mg L −1 with a considerable number of hotspots. The horizontal heterogeneity index of labile P varied from 0.04 to 4.5. High values appeared at the depths of 0–30 mm, likely reflecting an active layer of labile P under the sediment–water interface (SWI). Concentration gradients of labile P were observed from the high-resolution 1D DGT profiles in both the sediment and overlying water layers close to the SWI. The apparent diffusion flux of P across the SWI was calculated between −21 and 65 ng cm −2 d −1 , which showed that the sediments tended to be a source and sink of overlying water P in the algal- and macrophyte-dominated regions, respectively. The DGT-labile P in the 0–30 mm active layer showed a better correlation with overlying water P than the labile P measured by ex situ chemical extraction methods. It implies that in situ , high-resolution profiling of labile P with DGT is a more reliable approach and will significantly extend our ability in in situ monitoring of the labile status of P in sediments in the field. [ABSTRACT FROM AUTHOR]

Given the importance of β-alanine, the nitrilase BjNIT3397 from Bradyrhizobium japonicum strain USDA110 was examined toward the hydrolysis of 3-aminopropionitrile. It has been found that nitrilase BjNIT3397 effectively hydrolyzed 3-aminopropionitrile with substrate concentration up to 3 M (210 g/L) at the pH 7.3 and temperature 30 °C. With the increase of substrate concentration from 0.6 to 3 M, 3-aminopropanamide was formed and its percentage in the products was increased up to 33%. In order to reduce the formation of 3-aminopropanamide, aspartate ammonia-lyase and fumaric acid were added into the reaction system to consume the byproduct ammonia. As expected, the reaction was shifted toward the formation of β-alanine, resulting in the decrease of 3-aminopropanamide from 33% to 3%. Therefore, a tandem reaction strategy was developed to effectively prevent the formation of 3-aminopropanamide. This might also offer a possibility of producing β-alanine and l -aspartic acid in one process. [ABSTRACT FROM AUTHOR]

For out-of-plane relative equilibrium of a two-spacecraft formation achieved by internal forces, this paper proposes a scheme which complies with the characteristics of angular momentum conservation to analyze such a formation over the entire parameter space. By purposely rewriting one of the equilibrium condition, this paper defines a modification of the set of equations for the out-of-plane equilibrium configurations. Thereby, the relative equilibrium can be solved analytically in the whole multidimensional real number field through these equations. Numerical examples are also included to provide some insight about the equilibrium conditions. Moreover, the results from derivation and illustrative examples disclose a novel picture of the out-of-plane relative equilibrium. [ABSTRACT FROM AUTHOR]

The use of a dinuclear Cu 2 (II)-β-cyclodextrin complex (Cu 2 -β-CyD) as a chiral selector (CS) was successfully applied to chiral high speed counter-current chromatography (HSCCC) for the enantioseparation of aromatic α-hydroxycarboxylic acids. α-cyclohexylmandelic acid (CHMA) as a case was studied to optimize the separation temperature, the pH value of the aqueous phase, and the concentration of the chiral selector, which were comparatively studied between Cu 2 -β-CyD and native β-cyclodextrin (β-CyD) as CSs. The thermodynamic parameters of the formation of the complex between the enantiomers and the CSs were obtained, and the complex formation constants between the enantiomers and Cu 2 -β-CyD or β-CyD were determined using induced circular dichroism technology. The results indicate that Cu 2 -β-CyD can remarkably improve the enantioseparation compared with β-CyD, mainly due to the ion-pairing interactions between the deprotonation of carboxyl group of CHMA and the Cu(II) ion of Cu 2 -β-CyD. Five of other aromatic α-hydroxycarboxylic acids were also enantioseparated successfully by HSCCC using Cu 2 -β-CyD as a CS. [ABSTRACT FROM AUTHOR]

An efficient, clean, and environmental friendly ‘one-pot’ four-component reaction was developed for assembling a novel type of spirooxindole derivatives containing dihydropyridine and pyrrolidinone. The reaction could be easily performed in aqueous ethanol with 4-DMAP as catalyst in good yields. The high efficiency and the simple and mild condition of the reaction, in addition with its avoidance of time-consuming, costly syntheses, and tedious workup, endowed the reaction with application significance. A series of spirooxindole derivatives were therefore prepared in excellent yields by using this ‘one-pot’ four-component reaction method. [ABSTRACT FROM AUTHOR]

• An analytical preliminary design method for abort trajectory with a lunar flyby is proposed based on pseudostate theory. • Two parameters in the design process are taken as variables, then an ergodic representation of the feasible abort trajectories with a certain abort time is developed. • The performances of these abort trajectories in an ergodic representation including duration time, injection propellant and re-entry points distribution are investigated. • The effects of abort time and the nominal mission trajectory on abort trajectories are evaluated. This article proposes an analytical preliminary design method for abort trajectory with a lunar flyby and the trajectory ergodic representation based on parameterization, as well as their application in studying the abort trajectories' characteristics. First, by introducing two parameters, the perilune altitude and the perilune transfer time, the preliminary solution is developed parametrically using pseudostate theory to connect two special Lambert processes. The fast convergence of the improved differential correction under the high-fidelity gravity field verifies the accuracy of the proposed preliminary design method. Next, the two parameters are regarded as a set of variables to define an abort trajectory. Based on this, an ergodic representation of the abort trajectory with a certain abort time is yielded using the proposed design method, which offers a global view of the feasible abort trajectories. In addition, the influences of some factors on the performance of these abort trajectories are investigated based on the proposed design method and ergodic representation. The simulation results show that the abort time and the transfer time of the nominal trajectory significantly affect the ergodic representation and characteristics of the abort trajectory. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sodium alginate gel foam (SC-GF) was prepared based on biomass materials. • The gelation time of SC-GF was successfully controlled by weakly electrolytic calcium L-lactate as a cross-linking agent. • SC-GF exhibited excellent fire prevention and extinguishing properties. • The fire prevention and extinguishing mechanism of SC-GF was investigated. In order to address the environmentally friendly issue of fire prevention and extinguishing materials in coal mines, A new biomass sodium alginate gel foam (SC-GF) was prepared by using sodium alginate (SA), calcium L-lactate (CL), alkyl glycoside (APG) and tea saponin (TS). The effect of different concentrations of CL on the properties of SC-GF was analyzed by studying the gelation time, foaming volume and half-life of the SC-GF. The results show that the gelation time of SC-GF is successfully controlled by using the weak electrolyte CL as the cross-linking agent. When SA: CL: APG: TS = 4 : 1 : 2 : 1, the gelation time of SC-GF is 10 min with half-life of 16 days. Furthermore, A metal coordination bond favorable to the stability of SC-GF is formed by the carboxylate ion of α-L-gulonic acid in SA and Ca2+ ionized by CL. SC-GF exhibits excellent fire prevention and extinguishing properties. The CO concentration of the coal sample treated with SC-GF decreases from 7556.8 to 34.92 ppm in the process of oxidation at room temperature for 48 h. The temperature-programmed oxidation test shows that SC-GF can delay the accelerated oxidation temperature from 120 to 160 °C, and the CO inhibition rate is as high as 60.5 % at 200 °C. The fire extinguishing test indicates that SC-GF can significantly reduce the temperature of the coal sample and extinguish the coal fire quickly. The study is useful to develop efficient and environmentally friendly coal mine fire prevention and extinguishing materials. [ABSTRACT FROM AUTHOR]

Abstract: 3D hybrid analyses on the interlaminar stresses near the free edges of piezoelectric laminated plates are presented on the basis of three-dimensional piezoelasticity. The state space equations for cross-ply piezoelectric laminates subjected to a uniform axial extension are obtained by considering all the independent elastic and piezoelectric constants. With the application of the transfer matrix and recursive solution approach, the equations satisfy the traction-free and open-circuit boundary conditions at free edges and the continuity conditions across the interfaces between material layers. Three-dimensional exact solution is sought and validated by comparing the present analytical results with those from existing approximate and finite element models. The singularities of interlaminar stresses near free edges are observed and the significant electromechanical influence on the free-edge effect is found. [Copyright &y& Elsevier]

Highlights: [•] A new method for chiral separation of TVN racemate using HSCCC was established. [•] Induced circular dichroism was first applied to optimize the chiral HSCCC conditions. [•] This method could be applied to improve the production rate of the chiral separation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hg2+, MeHg, EtHg and PhHg were separated on two sequential 12.5-mm SCX columns. [•] The shortest separation time (2–2.5min) was consumed. [•] The mobile phase was most environment-friendly and fairly compatible with ICP-MS. [ABSTRACT FROM AUTHOR]

Highlights: [•] Four mercurial forms were separated via a 12.5-mm strong anion exchange column by complexing with 3-mercapto-1-propanesulfonate into negatively charged complexes. [•] The fastest analysis of mercury speciation in 5.0min was obtained so far. [•] The most environment-friendly mobile phase (1.0mM sodium 3-mercapto-1-propanesulfonate at pH 7.0) was employed. [•] Mercurial species in fish was determined by the proposed AEC–ICP-MS method. [ABSTRACT FROM AUTHOR]

Titanium/silica (Ti/SiO2) composites are fabricated using powder metallurgy (P/M). Nanoscale biocompatible SiO2 particles are selected as reinforcement for the Ti/SiO2 composite to enhance its biocompatibility and strength, especially when with high porosity. Effects of the SiO2 particle addition and sintering temperature on mechanical properties of the Ti/SiO2 composites are investigated. The results indicate that the mechanical property of Ti/SiO2 composites sintered at 1100°C are better than those at 900 and 1000°C. The strength of the Ti/SiO2 composites is significantly higher than that of pure titanium. The composite with the SiO2 content of 2wt% sintered at 1100°C for 4h shows an appropriate mechanical property with a relative density of 96.5%, a compressive strength of 1566MPa and good plasticity (an ultimate strain of 15.96%). In vitro results reveal that the Ti/SiO2 composite possesses excellent biocompatibility and cell adhesion. Osteoblast-like cells grow and spread well on the surfaces of the Ti/SiO2 composites. The Ti/SiO2 composite is a promising material for great potential used as an orthopedic implant material. [ABSTRACT FROM AUTHOR]

Maneuvering to a free return trajectory is a vital abort means for crewed lunar missions. A novel method of solving the fuel optimization of free return abort trajectory for Earth-Moon transfer by two-stage transformation on optimization model and Bayesian optimization is documented. Two new design variables—perilune altitude and transfer time from earth to perilune, instead of the original injection velocity vector, are introduced to transform the general model into a two-dimensional model. Each feasible abort trajectory is determined by a numerical method including initial estimate and exact solution. Then the characteristics of the relationship between the new variables and the fuel objective of impulse maneuver are applied to further transform the model into a one-dimensional model. Based on the Bayesian optimization method, fuel optimization is successfully and efficiently implemented for the free return abort trajectory at multiple abort moments during the Earth-Moon transfer. Furthermore, the influence of the initial Earth-Moon phase on the result of fuel optimization is presented. Numerical simulations are conducted to demonstrate the efficacy of the proposed method. • Fuel optimization of free return abort trajector. • y for Earth-Moon transfer is studied. • We propose a two-stage transformation method to overcome the difficulty of optimization model. • Bayesian Optimization method is applied to solve the optimization efficiently based on problem's characteristics. • The time window of abort trajectory and influence of the initial Earth-Moon phase is discussed. [ABSTRACT FROM AUTHOR]

Membranes with high permeance, excellent selectivity coupled with adequate solvent resistance are required for organic solvent nanofiltration (OSN) applications. But the "trade-off" relationship between the solvent resistance and permeance remains a critical challenge for polymeric-based thin film composite (TFC) membranes with necessary chemical crosslinking. Herein, a novel facile cyclization modification of polyacrylonitrile (PAN) nanofiber substrate is proposed by a simply thermal treatment and subsequent alkaline hydrolysis, and employed for the fabrication of TFC-OSN membrane for the first time in strong polar aprotic solvent systems. The reaction mechanism involved, solvent resistance and pore structure of PAN nanofiber substrate brought by the modification are investigated. TFC-OSN membrane supported by the modified PAN nanofiber substrate exhibits ultrahigh solvent permeance up to 13.3 L m−2 h−1 bar−1 coupled with a 99.7% rejection in rose bengal/DMF system and a good long-term stability. This study is therefore believed to provide useful guidelines for the development of next-generation OSN membranes. [Display omitted] • A facile cyclization modification of PAN with thermal and alkaline treatment is proposed. • Modified PAN nanofiber substrate shows enhanced resistance in strong polar aprotic solvents. • The substrate with high porosity shows superior pure solvent permeance. • TFC membrane exhibits superior OSN performance to most previous works. [ABSTRACT FROM AUTHOR]

Two metal organic frameworks based on flexible bis(benzimidazole) ligand, namely {[Co 2 (L) 2 (OBA) 2 ]·3H 2 O} n (1) and {[Zn(L)(OBA)]·H 2 O} n (2), were synthesized under hydrothermal condition. 1 and 2 can serve as probes for sensing acetylacetone and Fe3+ ions. [Display omitted] • Two new CPs based on bis(benzimidazole) ligands were synthesized and characterized. • 1 and 2 are dual-responsive probes for detection of acetylacetone and Fe3+ ions. • The luminescence sensing mechanisms can be ascribed to competitive absorption of energy and electron transfer. Two new metal–organic frameworks (MOFs), {[Co 2 (L) 2 (OBA) 2 ]·3H 2 O} n (1) and {Zn(L)(OBA)]·H 2 O} n (2) were constructed via N -donor and dicarboxylic acids co-ligands (L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)-2-propanol and H 2 OBA = 4,4′-oxybisbenzoic acid) under hydrothermal conditions and characterized by physico-chemical and spectroscopic methods. Two MOFs display 2D layers that are simplified as sql networks. 2 is further extended to 3D supramolecular framework via π–π stacking interactions. 1 and 2 feature high thermal and pH stability. Finally, both MOFs can serve as luminescence probes for sensing of acetylacetone and Fe3+ ions, the related sensing mechanisms are discussed in detail. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-flux loose NF membrane prepared by assembly of branched PEI and PEI-PO 3 Na. • Cross-linkable PEI and PEI-PO 3 Na enable the good stability of the membrane. • Chelatable phosphonate groups in PEI-PO 3 Na lower the membrane scaling tendency. • Membrane properties are optimizable by varying Mw of PEI-PO 3 Na. • Great potential for actual textile wastewater treatment is expected. Conventional nanofiltration membrane with high rejections to both dyes and inorganic salts are not suitable for the treatment of the textile wastewater. Herein, novel loose nanofiltration membranes were fabricated by the assembly of polyethyleneimine (PEI) and phosphorylated PEI (PEI-PO 3 Na) coupled with glutaraldehyde crosslinking. The PEI-based polyelectrolytes with branched structures and plentiful amine crosslinking sites enabled the formation of a highly permeable and robust selective layer. Meanwhile, the introduced phosphonate groups endowed the membrane with anti-fouling and anti-scaling properties owing to their surface hydrophilicity and chelation ability. By varying the molecular weight of PEI-PO 3 Na, the surface properties, pore size, and selective layer thickness and corresponding performances of the resultant PEI-PO 3 Na/PEI membranes can be successfully manipulated. The PEI-PO 3 Na 10 k/PEI membrane showed a high permeability (24.2 LMH/bar), high Victoria blue BO (99.5%) but low NaCl rejection (10.1%), demonstrating the best dye/salt fractionation performance. While PEI-PO 3 Na 70 k/PEI membrane exhibited the highest chroma and chemical oxygen demand (COD) removal rates, and the best anti-fouling ability for the textile wastewater treatment. The PEI-PO 3 Na/PEI membrane also exhibited good stability in various pH, and relatively low scaling propensity. This work provides a facile and convenient method for fabricating high-performance loose NF membranes for the practical textile wastewater treatment. [ABSTRACT FROM AUTHOR]

Highlights: [•] PLE–LC–MS/MS was firstly used for analyzing Curcuma wenyujin Y.H.chen et C.Ling. [•] A green and efficient method was used for pretreating traditional Chinese medicine. [•] Similar Curcuminoids were determined simultaneously without complete separation. [•] Operating parameters of PLE–LC–MS/MS were thoroughly optimized. [Copyright &y& Elsevier]

Abstract: Polychlorinated biphenyls (PCBs) possessed much potential hazard to environment because of its chemical stability and biological toxicity. Here, we identified the binding mode of a representative compound, PCB153, to human serum albumin (HSA) using fluorescence and molecular dynamics simulation methods. The fluorescence study showed that the intrinsic fluorescence of HSA was quenched by addition of PCB153 through a static quenching mechanism. The thermodynamic analysis proved the binding behavior was mainly governed by hydrophobic force. Furthermore, as evidenced by site marker displacement experiments using two probe compounds, it revealed that PCB153 acted exactly on subdomain IIIA (site II) of HSA. On the other hand, the molecular dynamics studies as well as free energy calculations made another important contribution to understand the conformational changes of HSA and the stability of HSA-PCB153 system. Molecular docking revealed PCB153 can bind in a large hydrophobic activity of subdomain IIIA by the hydrophobic interaction and hydrogen bond interactions between chlorine atoms and residue ASN391. The present work provided reasonable models helping us further understand the transporting, distribution and toxicity effect of PCBs when it spread into human blood serum. [Copyright &y& Elsevier]

Abstract: Pr2O3-doped Ba0.85Ca0.15Ti0.90Zr0.10O3 (BCTZ-xPr) ceramics were prepared by the conventional solid-state method. A tetragonal phase is only observed in these ceramics, and the introduction of Pr2O3 decreases their sintering temperature without affecting negatively the piezoelectric constant. Enhanced ferroelectric properties were obtained in these BCTZ-xPr ceramics. The ceramic with x=0.06wt% exhibits a good electrical behavior of d 33∼460pC/N, k p ∼47.6%, ε r ∼4638, and tan δ∼0.015 when sintered at a low temperature of ∼1400°C. As a result, the BCTZ-xPr ceramic is a promising candidate for lead-free piezoelectric ceramics. [Copyright &y& Elsevier]

Abstract: (0.89− x)(Bi0.5Na0.5)TiO3–0.11(Bi0.5K0.5)TiO3–xBa0.85Ca0.15Ti0.90Zr0.10O3 (BNT–BKT–BCTZx) ceramics were prepared by the conventional solid-state method. The dependence of BCTZ content on the microstructure and electrical properties of BNT–BKT–BCTZx ceramics is investigated. The BCTZ diffuses into the BNT–BKT lattice to form a stable solid solution, and a coexistence of rhombohedral and tetragonal phase is observed in these ceramics with the composition of 0.04≤ x ≤0.08. An enhanced piezoelectric behavior of d 33 ∼198 pC/N and k p ∼25.4% is demonstrated in the ceramic with x =0.06. Moreover, the introduction of BCTZ also improves the remanent polarization and decreases the coercive field, and the improvement in ferroelectric properties of 2P r ∼48.77μC/cm2 and 2E c ∼52.92kV/cm is observed in such a ceramic with x =0.06. As a result, the BNT–BKT–BCTZx ceramic is a promising candidate for lead-free piezoelectric materials. [Copyright &y& Elsevier]

Abstract: A new set of relative orbit elements is strictly defined through spherical geometry. The exact transformation equations between the new relative orbit elements and classical-orbital elements are derived. A new relative motion model with no singularity problem is derived based on the relative orbit elements, which are suitable for both elliptical and circular reference orbits. The in-plane and out-of-plane relative motion can be completely decoupled based on the new model. The inverse transformation of state transfer matrix is obtained to analyze perturbation effects and control strategy. The geometric characteristics of relative motion can be easily described using the relative eccentricity/inclination vector method. The proposed method and conclusions are validated by simulation through some typical examples. This paper improves the basic theory of relative orbit elements and unifies the expressions of the elliptical and near-circular close relative motion. [Copyright &y& Elsevier]

Abstract: By considering the single-photon absorption (SPA) and two-photon absorption (TPA) processes in the GaAs saturable absorber, the coupled rate equations for a diode-pumped passively Q-switched and mode-locked (QML) laser with GaAs coupler under Gaussian approximation are given. The key parameters of an optimally coupled passively QML laser can be obtained by numerically solving these equations. These key parameters include the parameters of the gain medium, the saturable absorber and the resonator, which can maximize the pulse energy of singly Q-switched envelope. Sample calculations for a diode-pumped passively Q-switched mode-locked c-cut Nd:GdVO4 laser with a GaAs saturable absorber are presented to demonstrate the optimal method applicable. [Copyright &y& Elsevier]

Abstract: In the present work, microwave-assisted extraction method in combining with liquid chromatography–tandem mass spectrometry (LC–MS/MS) was proposed for the determination of cyanuric acid (CYA) in infant formula samples. The separation was performed on a MERCK ZIC HILIC column (150×2.1mm i.d., 5μm) with gradient elution of 20mM ammonium acetate solution – acetonitrile. The method could respond linearly with cyanuric acid at concentrations from 1.0 to 50ngmL−1 with a quantification limit of 0.25mgkg−1. The intra- and inter-day precision was less than 4% and the recovery of the assay was in the range of 86.7–93.1%. In the analysis of practical spiked infant formula samples, the new method yielded satisfactory results. Due to its simplicity and accuracy the straightforward method is particularly suitable for routine cyanuric acid detection. [Copyright &y& Elsevier]

Abstract: This work reports a new sensitive multi-residue liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for detection, confirmation and quantification of six neonicotinoid pesticides (dinotefuran, thiamethoxam, clothiandin, imidacloprid, acetamiprid and thiacloprid) in agricultural samples (chestnut, shallot, ginger and tea). Activated carbon and HLB solid-phase extraction cartridges were used for cleaning up the extracts. Analysis is performed by LC–MS/MS operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Quantification was carried by the internal standard method with D4-labeled imidacloprid. The method showed excellent linearity (R 2 ≥0.9991) and precision (relative standard deviation, RSD≤8.6%) for all compounds. Limits of quantification (LOQs) were 0.01mgkg−1 for chestnut, shallot, ginger sample and 0.02mgkg−1 for tea sample. The average recoveries, measured at three concentrations levels (0.01mgkg−1, 0.02mgkg−1 and 0.1mgkg−1 for chestnut, shallot, ginger sample, 0.02mgkg−1, 0.04mgkg−1 and 0.2mgkg−1 for tea sample), were in the range 82.1–108.5%. The method was satisfactorily validated for the analysis of 150 agricultural samples (chestnut, shallot, ginger and tea). Imidacloprid and acetamiprid were detected at concentration levels ranging from 0.05 to 3.6mgkg−1. [Copyright &y& Elsevier]

Abstract: When a new product development team faces challenges, such as the cross-functional knowledge conversion task, both simple and existing organizational structures are comprised of various management methods and knowledge characteristics, analogous to a fully armed military force. However, these features are not arranged in order of priority. Each step within the knowledge conversion process of new product development may not require such a full depot of management methods and keynotes. Therefore, this study adopted Blackler’s perspective to examine the suitable organizational knowledge structure for cross-functional knowledge conversion within new product development teams. This study found that the continual steps of socialization, externalization, combination, and internalization in the new product development team’s knowledge conversion process were positively related to various organizational knowledge structures based on a survey of 107 Taiwanese high-technology small and medium-sized enterprises’ new product development teams – not merely a simple structure for all steps. Thus, these results confirm that complex structures are required to perform knowledge conversion. Socialization requires knowledge characteristics from both the communication-intensive organization and the symbolic-analyst-dependent organization. Externalization requires elements of knowledge from the communication-intensive organization, the symbolic-analyst-dependent organization, and knowledge-routinized organization. Combination requires features from the knowledge-routinized organization, and internalization requires characteristics from the expert-dependent organization. In addition, this study attempted to integrate the knowledge features from communication-intensive organization and symbolic-analyst-dependent organization structures for the socialization and externalization stages. This effort concentrated on solving novel and irregular problems through a simplification of the complex organizational structures which make the new product development’s knowledge conversion run smoother. [Copyright &y& Elsevier]

Abstract: A new method based on pressurised liquid extraction (PLE) followed by liquid chromatography–triple quadrupole linear ion trap mass spectrometry (LC–QTrap-MS) analysis has been developed for the identification and quantification of four major alkaloids in extracts of Corydalis decumbens (Thunb.) Pers. PLE extractions were performed using 90% ethanol; temperature was set at 100°C and pressure at 1500psi. HPLC analysis was performed on a Waters XBridge™ C18 column (150mm×2.1mm i.d., 3.5μm) eluted by a mobile phase of acetonitrile and 0.2% acetic acid. Data acquisition was carried out in multiple reaction monitoring transitions (MRMs) mode, monitoring two MRM transitions to ensure an accurate identification of target compounds in the samples. Additional identification and confirmation of target compounds were performed using the enhanced product ion modus (EPI) of the linear ion trap. The novel LC–QTrap-MS platform offers the best sensitivity and specificity for characterization and quantitative determination of the four alkaloids in C. decumbens (Thunb.) Pers. and fulfils the quality criteria for routine laboratory application. [Copyright &y& Elsevier]

Abstract: The diurnal atmospheric phosphine (PH3) concentrations and fluxes at the water–air interface in Lake Taihu were reported. The results showed that the PH3 flux at the water–air interface ranged from −69.9±29.7 to 121±42ngm−2 h−1, with a mean flux of 14.4±22.5ngm−2 h−1. The fluxes were both negative and positive during the diurnal period, indicating that the lake can act as a sink and a source of PH3. In addition, the PH3 fluxes were positively correlated with water temperature, total soluble phosphorus and soluble reactive phosphorus, while they were negatively correlated with water redox potential. A similar diurnal variation curve of atmospheric PH3 concentrations was observed during all four seasons, with the maximum level occurring in early morning and the minimum appearing around midday. These findings suggest that light plays an important role in the elimination of atmospheric PH3. A significant positive correlation was also found between air temperature and atmospheric PH3 concentration. The mean flux of PH3 in Lake Taihu was higher than in other reported wetlands, with an estimated annual emission of PH3 to the atmosphere of 2.94×105 gy−1. [ABSTRACT FROM AUTHOR]

Abstract: Owing to some desirable properties, ionic liquids (ILs) have attracted increasing interests and applications in many domains. Unfortunately, however, they generally have much higher viscosities than conventional molecular solvents, which result to some problems of handling or transferring in chemical processing. ILs with lower viscosity are desired. Therefore, understanding the relationship between micro-structure and macro-viscosity along with a comprehensive viscosity data is important for the synthesis and rational design of ILs with low viscosity. In this work, a comprehensive collection of viscosity data covering the period of 1983–2009 is conducted on the pure imidazolium-based ILs, and quantitative structure–property relationship (QSPR) study is performed for four selected data sets. The four correlations are obtained with R 2 >0.93, and quantum-chemical descriptors gave significant contributions. The cation–anion electrostatic interaction has the significant effects on the viscosity of imidazolium-based ILs, while other interactions (e.g., interionic hydrogen-bond, van der Waals) or micro-characteristics (e.g., molecular orbital, electronic population, dipole moment, volume, shape, branching degree, symmetry) also give some effects. [Copyright &y& Elsevier]

Water security is one of the most pressing global challenges due to its effects on human health. To face the challenge of water pollution, membrane technology was widely applied for the removal of pollutants and desalination. In this work, an enzyme-like ligand, Iron (III)-tetraamidomacrocyclic ligand (Fe(III)-TAML), was for the first time immobilized into a polyethersulfone (PES) membrane for the catalytic oxidation removal of micropollutants during the ultrafiltration process. Through the introduction of graphene oxide-polyethyleneimine (GO-PEI), Fe(III)-TAML was successfully immobilized into the membrane. Results shown that porosity and hydrophilicity of the PES membrane were significantly enhanced after GO-PEI modification. Furthermore, about 100% of bisphenol A (BPA) in the feed water was removed after filtration using the Fe(III)-TAML immobilized membrane at a high flux of 192 L/m2 h, which was attributed to the generation of high valence Fe through activating Fe(III)-TAML by H 2 O 2. Moreover, the Fe(III)-TAML in the membrane could be simply regenerated by a re-adsorption process, and the flux and removal efficiency of BPA were stabled during five cycles. Additionally, the TAML/GO-PEI/PES membrane maintained a high water flux and BPA removal efficiency for the filtration of actual surface water. Overall, these results highlight the potential of enzyme-like ligand catalytic oxidation coupled with ultrafiltration to remove micropollutants at a high flux for ensuring the water safety. [Display omitted] • Enzyme-like ligand was first coupled with UF membrane for micropollutant removal. • BPA in actual water was well removed by filtration using TAML/GO-PEI/PES membrane. • TAML on the membrane could be regenerated by a simple re-adsorption process. • The oxidation process of TAML/H 2 O 2 was helpful for the membrane antifouling. [ABSTRACT FROM AUTHOR]

The recent decades have witnessed a tremendous growth in the number of satellites and debris in space, leading to an increasingly high risk of collision between space objects. Collision warning aims at assessing the collision risk between space objects and attempts to identify possible collisions in order for satellites to perform evasive maneuvers in advance. Current collision warning methods are based on the computation of collision probability and comparison with some tolerance threshold. Such a threshold is usually set according to experience. In contrast, this paper proposes to use covariance ellipsoid with a user defined Mahalanobis distance to represent the most possible region in which the relative position vector distributes. Zero vector represents the collision event, and once it enters this ellipsoid, a collision warning occurs. A collision warning function along with a definite threshold is then formulated based on this criterion. Moreover, in order to rapidly predict the possible collision intervals, a self-adaptive Hermite interpolation technique is applied to approximate the collision warning function by piecewise cubic polynomials for efficient roots finding. Finally, the proposed collision warning criterion has been evaluated in several collision scenarios. Comparison experiments are also conducted with the brute force method and analytical propagators. The simulation shows that the calculation of collision warning interval based on the proposed criterion is effective, and the self-adaptive Hermite interpolation method performs high efficiency and accuracy. [ABSTRACT FROM AUTHOR]

A new 2D luminescent metal–organic framework, [Co(L)(1,4-NDC)]n (1), was successfully assembled. 1 possesses high selectivity and sensitivity to detect dichloromethane (DCM) and Fe3+ via turn-on effect and turn-off method, respectively. [Display omitted] • A new Co(II) metal–organic framework was synthesized and characterized. • 1 can be as a dual-response sensor to detect dichloromethane (DCM) and Fe3+ ions. • 1 is the first example of turn-on fluorescent sensor based on MOFs for the detection of DCM. A new luminescent Co(II)–organic framework, [Co(L)(1,4-NDC)] n (1) (L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)propane, 1,4-H 2 NDC = 1,4-naphthalene dicarboxylic acid), was solvothermally synthesized. 1 shows a binodal 3,4-connected layer with the 3,4L27 topological network. Moreover, 1 possesses high thermal stability and can be used as a sensor for selective and sensitive detection of dichloromethane (DCM) and Fe3+ ions via luminescence enhancement mode (turn-on) and luminescence quenching effect (turn-off), separately. 1 represents a rare probe for sensing DCM and Fe3+ ions based on metal–organic frameworks. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two new CPs based on bis(benzimidazole) ligands were synthesized. • 1 and 2 are dual-responsive probes for detection of acetylacetone (acac) and Fe(III). • The luminescence quenching mechanism was discussed. Two new ternary coordination polymers (CPs), [Cd 0.5 (TBTA) 0.5 (L1)] n (1) and [Cd(TBTA)(L2)(H 2 O)] n (2) (L1 = 1,3-bis(2-methylbenzimidazol-1-yl)-2-propanol, L2 = 1,2-bis(benzimidazol-1-ylmethyl)benzene, H 2 TBTA = tetrabromoterephthalic acid) were prepared under the hydrothermal condition. 1 possesses a 1D infinite chain. 2 features a 4-connect sql layer with point symbol of {44.62}. Both 1 and 2 are further extended into the 3D supramolecular networks via O H⋯N and O H⋯O hydrogen-bonding interactions, respectively. The structural variety of the Cd(II) ternary CPs demonstrates that different N -containing ligands play great influence on the final topological network. Luminescence titration results display that 1 and 2 are dual-responsive probes for detection of acetylacetone (acac) and Fe3+ ions. [ABSTRACT FROM AUTHOR]

Abstract: High-performance liquid chromatographic (HPLC) was developed for fingerprint analysis of Pseudostellaria heterophylla (Miq.) Pax. Liquid chromatography–electrospray ionization-time-of-flight mass spectrometry (LC–TOF-MS) technique was first employed to identify the components of the fingerprint. Twelve major peaks in chromatographic fingerprint were analyzed by on-line LC–TOF-MS analysis; one cyclic peptide was unequivocally identified and five cyclic peptides were tentatively assigned based on their MS data. These cyclic peptides served as the marker peaks in the HPLC fingerprints. The chromatographic fingerprints have been analyzed by similarity index calculations and hierarchical clustering analysis (HCA). The result showed that the HPLC fingerprints could be used to determine the optimal harvest time for P. heterophylla (Miq.) Pax and to authenticate the species of the herb. [Copyright &y& Elsevier]

Abstract: In this paper a novel scheme is proposed where with the help of Victor (a state preparer) an unknown EPR pair is copied in a certain probability so that three parties of communication can obtain the EPR state, respectively. The first stage of this scheme is to teleport an unknown EPR state to Carla (one receiver). The second stage of this scheme, Alice (a sender) and Bob (the other receiver) get the same EPR pair or an orthogonal-complement copy of the EPR pair with the help of Victor. [Copyright &y& Elsevier]

Li-rich layered oxides can provide high energy density, but their further application is hindered by capacity decrease and voltage decay in the course of cycling. Herein, we blended layered oxide Li 1.2 Mn 0.6 Ni 0.2 O 2 (LL) with olivine structured LiMn 0.8 Fe 0.2 PO 4 /C (LFMP) cathode material via a simple method, with improved results of excellent cycle stability, low voltage decay and good thermal stability. The result of TEM and ICP reveals that the LL enabled by LFMP can mitigate the surface-induced phase transition (layered to spinel) and suppress Mn dissolution of LL. As a consequence of CV and GITT test and analysis, the buffer effect of LFMP for LL is benefit to support the layered structure in subsequent cycles, which can provide the long cycle capacity and lower voltage decay for the hybrid materials. • A hybrid materials was prepared via a simple and economical method. • The as-prepared materials show excellent cycle stability and low voltage decay. • The LO20 sample shows a capacity retention of 81.6% after 500 cycles at 1C. • The voltage decay rate was reduced from 1.36 mV of LL to 0.68 mV of LO20 per cycle at 1C. • LL enabled by LFMP can mitigate phase transition and suppress Mn dissolution of LL. [ABSTRACT FROM AUTHOR]

Research on the frequency of transitions, or transition markers, has led to contested claims. Comparisons by L1 speaker (e.g. Leedham, 2015; Lei, 2012) argue that Chinese writers overuse and underuse certain transitions when compared to L1 English writers. Moreover, Biber et al. (1999) suggest transitions are frequent in technical scientific writing, while Hyland (2005) suggests they are more frequent in the discursive writing of the soft disciplines. Our study contributes to both these areas with evidence from a contrastive analysis of transition use by Chinese and English writers in the Han CH-EN corpus, a closely matched corpus of successful university student writing in English. A frequency comparison of transition use by Chinese and English writers finds no significant difference for most transitions. The transition used most often by both groups is however , which is examined across contexts. English writers use however significantly more than Chinese writers, but only in a small number of disciplines, genres and sentence positions. An examination of the literacy practices in these contexts suggests that terms such as 'overuse' and 'underuse' with their negative connotations should only be used when frequency data is combined with investigations of appropriate use in context. [ABSTRACT FROM AUTHOR]

• We present a novel unsupervised domain adaptation solution based on collaborative representation which seeks for the close samples between domains and uses them to assist further predictions. Plenty of experiments validate the effectiveness of our method and more general, we can solve domain adaptation problems without reducing domain discrepancy explicitly, which is different from previous methods. • Curriculum sample choosing is proposed to select the close samples between domains based on reconstruction residual. Then these samples are added to training set for subsequent prediction. • We propose distance-aware sparsity regularization to learn more reasonable representation, so that samples have smaller distance to the query sample are intended to have larger weights. Domain adaptation aims at leveraging rich knowledge in the source domain to build an accurate classifier in the different but related target domain. Most prior methods attempt to align features or reduce domain discrepancy by means of statistical properties yet ignore the differences among samples. In this paper, we put forward a novel solution based on collaborative representation for classifier adaptation. Similar to instance re-weighting, we aim to learn an adaptive classifier by multi-stage inference and instance rearranging. Specifically, a curriculum learning based sample selection scheme is proposed, then the chosen samples are integrated into training set iteratively. Due to the distribution mismatch of two domains, we propose distance-aware sparsity regularization to learn more flexible representations. Extensive experiments verify that the proposed method is comparable or superior to the state-of-the-art methods. [ABSTRACT FROM AUTHOR]