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The development of a facile approach to simultaneously detect and separate Hg(ii) ions in an aqueous solution is a challenging topic in the chemosensing field. Herein, we focus on constructing the Hg(ii)-sensitive fluorescence “turn-on”-type composite materials by using halloysite nanotube (HNT) as substrate. Two types of HNTs-based chemosensors, HNTs-PHT and HNTs-BP, were developed in this study, which exhibit Hg(ii)-sensitive fluorescence “turn on” behavior by forming interparticle and intraparticle excimers, respectively. Fortunately, HNTs-PHT is able to effectively restrict the solvent relaxation of π–π* transition and make it a better detection tool in aqueous solution than HNTs-BP. The addition of Hg(ii) can trigger a dramatical increase at 469 nm in emission curves of HNTs-PHT, which cannot exhibit emission behaviors without the addition of Hg(ii). Furthermore, the formation of interparticle excimers makes Hg(ii) serve as a crosslinker to aggregate HNTs-PHT into precipitations. Following this way, Hg(ii) ions can be facilely removed from the water via a simple filtration or centrifugation approach. The as-prepared HNTs-PHT shows high specificity and precision in simultaneously detecting and separating Hg(ii) without the recourse to energy consumption, which will give a novel insight to deal with heavy metal pollution.

A Gram-stain-negative bacterium, designated as strain TK19100T, was isolated from the mid-ridge of the Southwest Indian Ocean. Cells of strain TK19100T were strictly aerobic, non-motile and short-rod shaped with fimbriae-like structures around the cell surface. Growth occurred at 15–40 °C, at pH 6.0–9.0 and with 1–10% (w/v) NaCl. Strain TK19100T shared the highest 16S rRNA gene sequence similarity with Cerasicoccus frondis NBRC 105381T of 97.74%, followed by Cerasicoccus arenae KCTC 12870T of 97.69% and Cerasicoccus maritimus NBRC 105382T of 97.40%. The phylogenetic tree based on both 16S rRNA genes and 92 core genes placed strain TK19100T in a new linage within the genus Cerasicoccus. The genome size of strain TK19100T was 5.07 Mb with the DNA G + C content 56.1%. The average nucleotide identity value and the digital DNA-DNA hybridization value of strain TK19100T compared with the closest related species, Cerasicoccus frondis, were 78.39% and 23.70%, respectively. Strain TK19100T encoded a previously unreported combination of GH16 and Carbohydrate Binding Module 96. The major fatty acids of strain TK19100T were C14:0 and C18:1ω9c. Menaquinone-7 was the sole respiratory quinone. The phenotypic and genotypic characterization analysis indicate that strain TK19100T represents a novel species affiliated to the genus Cerasicoccus, for which the name Cerasicoccus fimbriatus sp. nov. is proposed. The type strain is TK19100T (= CGMCC 1.18957T = NBRC 116189T). [ABSTRACT FROM AUTHOR]

A precise constitutive model is the foundation and key to finite element simulation in material volume forming and the optimization of the hot working process. Hence, to build a precise constitutive model, a method based on a genetic algorithm (GA) for the inverse optimization identification of parameters is presented in this paper. The idea of this method is to continuously adjust the model parameters through GA until the objective function reaches the minimum value. In this study, hot compression experiments were performed on the Gleeble-1500D thermal simulator at temperatures ranging from 800 °C to 1000 °C and strain rates of 0.01 s−1 to 1 s−1. The Arrhenius-type (A-T) model considering strain compensation and the Johnson–Cook (JC) model considering the coupling effects of strain, temperature and strain rate were constructed, respectively, by using the regression method and the parameter inverse optimization identification method. For the purposes of comparing and verifying the reliability of the predictions of the two established constitutive models, the correlation coefficient (R), average absolute relative error (AARE), and relative error (RE) were adopted. The results show that both the optimized A-T model and the optimized JC model have high prediction accuracy. Compared to the optimized JC model, the optimized A-T model demonstrated a higher correlation coefficient, by 0.003, and a lower average absolute relative error, by 1.43%. Furthermore, the relative error distribution of the optimized A-T model was found to be more concentrated than that of the optimized JC model. These results suggest that the A-T model is more appropriate than the JC model for characterizing the high-temperature deformation behavior of Ti6Al4V alloy. [ABSTRACT FROM AUTHOR]

Ti6AL4V alloy is widely used in the biomedical and energy vehicle industries, among others. Ti6Al4V alloy cannot be fabricated at ambient temperatures; hence, it requires hot forming. However, this method is susceptible to crack defects. The crack defect problem of Ti6AL4V alloy in the hot-forming process cannot be ignored, so we must develop a precise hot-forming damage prediction model. In this study, three high-temperature damage models of Ti6Al4V alloy were developed, considering the temperature and strain rate. These models were derived from the normalized Cockcroft and Latham (NCL), Oyane, and Rice and Tracey (RT) damage models. The damage parameters of the models were identified using a genetic algorithm combined with finite element simulation. The force accumulation error of the Ti6AL4V alloy specimen, which was obtained from a simulated thermal tensile test and an actual test, was used as an optimization target function. Then, the damage parameters were optimized using the genetic algorithm until the target function reached the minimum value. Finally, the optimal damage model parameter was obtained. Through program development, the three high-temperature damage models established in this paper were embedded into Forge® NxT 2.1 finite element software. The simulated thermal tensile test of Ti6AL4V alloy was performed at a temperature of 800–1000 °C and a strain rate of 0.01–5 s−1. The simulated and actual fracture displacements of the tensile specimens were compared. The correlation coefficients (R) were calculated, which were 0.997, 0.951, and 0.912. Of the high-temperature damage models, the normalized Cockcroft and Latham high-temperature damage model had higher accuracy in predicting crack defects of Ti6Al4V alloy during the hot-forming process. Finally, a fracture strain graph and a high-temperature damage graph of Ti6Al4V alloy were constructed. The Ti6Al4V alloy damage evolution and thermal formability were analyzed in relation to the temperature and strain rate. [ABSTRACT FROM AUTHOR]

For nonfullerene acceptor (NFA) based organic solar cell (OSC), a small HOMO offset favors the high open-circuit voltage (Voc), while a large one facilitates the charge separation. To simultaneously achieve efficient charge separation and low voltage loss in OSCs, we synthesized four 10,11-dihydrodiindeno[1,2-b:2′,1′-d]thiophene (DIDT)-based NFAs, namely S1-N1F, S1-N2F, S2-N1F, and S2-N2F, by modifying the end groups and side chains and obtaining tunable HOMO offsets of 0, 0.03, 0.04, and 0.06 eV, respectively, when blended with PBDB-T. S1-N1F:PBDB-T-based OSCs with a HOMO offset of 0 eV show the lowest short circuit current density (Jsc) and fill factor (FF) values, resulting in an unsatisfactory power conversion efficiency (PCE) of 7.94%, due to insufficient driving force for effective charge separation. Regardless of near zero HOMO offset (0.03 eV), S1-N2F:PBDB-T-based OSCs give the highest PCE of 13.59% with a high Voc of 0.94 V along with a comparable FF up to 74.30%. S2-N1F- and S2-N2F-based OSCs give moderate PCEs of 10.35 and 11.59% with Jsc values of 17.07 and 17.82 mA cm−2, and FF values of 62.14 and 70.33%, respectively. Femtosecond transient absorption (fs-TA) measurements indicate that S2-N1F and S2-N2F with large HOMO offsets have faster interfacial hole transfer and charge recombination processes. This study demonstrates that high-performance OSCs can be achieved by blending the donor and acceptor with a near zero HOMO offset, which can provide valuable experience for designing highperformance NFAs. [ABSTRACT FROM AUTHOR]

Ice accumulation on high voltage insulators can cause accidents by flashover across the ice-covered insulators. The ice accumulation can be reduced by changing the insulator surface properties by application of a semiconducting RTV silicone coating. This method is based on the hydrophobicity and semiconductivity properties of the coating. The mechanism for reducing ice accretion is analyzed theoretically. Experimental results are presented to validate the effectiveness of the semiconducting RTV coating at reducing ice on insulator strings. The results show that the coating on the insulators delays ice formation and reduces the amount of ice. Index Terms--Ice, insulator, semiconducting, coating, RTV, flashover, hydrophobicity.

Based on artificial icing test results, it was found that the dc flashover voltage of iced insulator strings was non-linear with different string lengths. An experimental formula of flashover voltage on iced insulators of different string lengths is introduced in this paper. Icing tests were carried out on different kinds of insulators including DC antifog, double-shed and three-shed insulators. Under serious ice conditions, the DC flashover voltages of the different types of insulator strings were very close. The flashover voltage of energized iced strings was a little higher than that of de-energized ones. Index Terms--Iced insulator string, dc flashover, flashover, overhead line.

Power girds in different countries face different types of threats and in China the threats severely affecting grid reliability were in the past large power outage accidents caused by pollution flashovers. First records of pollution flashover accidents in China can be traced back to 1950s in industrial areas in Northeast and East China. Thereafter, such accidents occurred occasionally, but after 1970s they started to expand and were recorded in most of the country's provinces. The very first large area outage accident caused by pollution flashover happened in early 1974 in Northeast China around the local largest cities Shenyang and Fushun. Between 1971 and 1994, 3542 pollution-caused line trip-outs (several trip-outs on one overhead line (OHL) happening the same day is counted in China as a single event) were recorded on 35–500 kV OHLs and 1768 substation trip-outs. A total of 44 large area outage accidents caused by pollution flashovers took place during the 30 year period before 2007, as shown in Figure 1, while the outages recorded between 1981 and 2001 accounted for 43% of the total number. Among them, outages of super large character occurred every 5–6 years, e.g., in 1990 in North China and Northeast China, in 1996–1997 in East China and Central China, 2001 in North China and Northeast China [1–3]. Here we refer to the large area outage accidents as flashover events on several main transmission overhead lines and substations, appearing during one or several consequent severe meteorological events and continuing for several days. They affect several big cities within one province and stretch over an area of less than 100 thousand km2. For super large area outage accident, we refer to the accidents stretching across several provinces over the area of 200–300 thousand km2 and resulting in hundreds of pollution flashover events. [ABSTRACT FROM AUTHOR]

Microwave far-field imaging techniques are well suited to image source, scatterers, and anomalies in dielectric or composite materials. However, the diffraction limits restrict the resolution of far-field imaging. This contribution focuses on the feasibility of designing a metamaterial lens based sensor for enhancing the resolution of microwave far-field imaging. Metamaterials have been increasingly used in the past few decades for the designing of novel microwave circuits and sensor systems. The unique properties of metamterials offer several advantages, such as sub-wavelength nature, compact design, and super-resolution, which is not found in the conventional materials. The feasibility of enhancing imaging resolution using a metamaterial lens along with time reversal processing of far-field microwave data is studied in this paper. Specifically, the super-resolution capability of the lens for detection of sub wavelength defects inside the composite materials is presented. [ABSTRACT FROM AUTHOR]

Eddy current methods are commonly used in the inspection of riveted multilayer structures. In a practical scenario, steel rivets may be magnetized to varying levels which can distort the magnetic field and pose a major challenge since the distortion can result in false positives and negatives. This paper presents an invariance transformation procedure that renders the signal insensitive to changes in magnetization while retaining the sensitivity to defect information. The approach is first implemented on simulated data, where the signals from magnetized steel rivets can be generated under controlled variation of relative permeability. The algorithm is then validated on experimental data acquired using steel rivets with different residual magnetization levels. [ABSTRACT FROM AUTHOR]

Metallic tube inspection techniques using eddy current probes have evolved over the years from those employing a single bobbin coil to rotating coils and arrays, in an attempt to improve the speed and reliability of inspection. This paper presents a novel eddy current transceiver probe design that uses a rotating electromagnetic field. The transceiver coils consist of three identical windings located 120° apart on the same physical axis. A three-phase sinusoidal current source is used for exciting the coils. The phase voltages are identical in amplitude, but 120° apart in phase. The rotating magnetic field generated by the three-phase current is sinusoidal in space and time and so are the induced eddy currents in the tube wall. The sensor achieves mechanical rotating probe functionality by electronic means and eliminates the need for mechanical rotation. The terminal voltages of the three-phase windings can be measured during the scan. The defect’s axial and angular position can be estimated by analyzing the amplitude and phase of the sum of the three terminal voltage signals. The probe is sensitive to defects of all orientations and is as effective as conventional rotating pancake coil probes while offering the advantages of high inspection speed and greater reliability, since the probe does not rotate mechanically. A 3-D finite-element model based on reduced magnetic vector potential Ar, V -Ar formulation was developed to simulate and predict the response of the probe to a variety of defects. A prototype unit consisting of a probe connected to a three-phase constant current source and data acquisition system was developed and tested. Experimental results validating the simulation model and demonstrating the feasibility concept are presented. [ABSTRACT FROM PUBLISHER]

A novel methodology that combines high performance liquid chromatography with photodiode-array detector (HPLC-DAD) coupled with second-order calibration method based on alternating trilinear decomposition (ATLD) algorithm was used in determination of the effective constituents such as costunolide and dehydrocostuslactone, in plasma sample and Chinese patent medicine Xiang Sha Yang Wei (XSYW) capsule. Complicated systems such as plasma and Chinese patent medicine which have intricate components are tedious to isolate and purify. The problem that chromatographic peaks are heavily overlapped among the analytes and interferents from the background matrices can be resolved, and the satisfactory quantification results have been gained with the help of the ATLD algorithm which utilized "mathematical separation" instead of partial "physical or chemical separation". Meanwhile, HPLC-MS/MS method was used to validate the accuracy of the proposed determination method. [ABSTRACT FROM AUTHOR]

Symmetric ladder-type oligo( p -aniline)s and poly( p -aniline)s were successfully synthesized by an intramolecular ring closure in a highly efficient S N Ar reaction from oligo( p -phenylene)s and poly( p -phenylene)s with fluorine (F) and secondary amine (NH) groups. Unlike Cadogan ring closure, the newly designed cyclization reaction will not produce a mixture of symmetric and nonsymmetric structures. Moreover, the introduction of the F atom does not hinder Suzuki polymerization. The result indicates that preparing regular oligomers and polymers with a nitrogen bridge is possible.

The pyrolysis (Py)-GC-MS technique was first introduced for the identification of two kinds of Chinese geographical indication vinegars because its advantages are that it is a simple and convenient sample pretreatment and inlet method. Abundant Py information about vinegars was obtained using Py-GC-MS; 21 common peaks were selected. With the help of the classical partial least-squares (PLS) modeling method for data analysis, two identification models for Shanxi extra-aged (SX) and Zhenjiang (ZJ) vinegars were established, respectively. An N-reducing method was used to select the variables. The variables were reduced one at a time to build the PLS models with the lowest number of misjudgments. Both models had good recognition rates, identifying over 90% of samples correctly. Thus, combining Py-GC-MS and PLS could be regarded as an effective method for the identification of SX and ZJ vinegars.