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Based on the modified KM (Kock–Mecking) model, a cutting constitutive model of AA7050-T7451 considering anisotropy is established in this article. With the aid of high-speed cutting FEM simulation and experiment, the micro-influence mechanism of anisotropy on high-speed cutting hardening of AA7050-T7451 was studied from three aspects: micro-morphology, residual strain, and plastic deformation. By analyzing the macro-micro correlation mechanism of dislocation density, work hardening, and cutting temperature, a "Three-Stage" model of work hardening is put forward. The results show that the work-hardening behavior of high-speed cutting AA7050-T7451 shows obvious anisotropic characteristics. And the work hardening degree is less than 0° and 90° at the material forming angle of 45°. At the 45° forming angle, the material dislocation density is the highest, and the grains are most prone to the dislocation slip. The macroscopic properties show that the microhardness of the material is small. The "Three-stage" model reveals the micro-evolution mechanism of work-hardening behavior. It is found that the dislocation density dominates the work-hardening behavior in stages I and II, and cutting temperature dominates the work-hardening behavior in stage III. The microhardness of the material increases sharply at first and then tends to be flat. [ABSTRACT FROM AUTHOR]

The North Qaidam Orogenic Belt (NQOB) is characterized by widespread Palaeozoic magmatism and high to ultrahigh-pressure metamorphism that provides important information regarding the continental crust growth and tectonic evolution in the North Qaidam. Our work focuses on the geology, geochronology, whole-rock geochemistry, and Sr–Nd isotopy of granitoids in the Tanjianshan area in the northern NQOB. The results indicate that the 486–469 Ma adakitic and TTG-like granitoids originated from the partial melting of Middle–Late Mesoproterozoic lower crustal materials with the addition of juvenile mafic lower crust at high pressures under an active continental margin setting. The 396–392 Ma I-type granitoids originated from the partial melting of juvenile crustal materials with the addition of ancient crustal component in a post-collisional setting. Geochronological studies show that there are significant regional differences in magmatism between the northern and rest parts of the NQOB. In the northern part, extensive and prolonged magmatism was widespread during oceanic subduction (~526–460 Ma) and post-collisional extension (~420–350 Ma) but magmatism in the stage of orogenic collision was absent. The Early Palaeozoic adakitic magmatism suggest a significant continental crustal reworking in a subduction zone during 486–469 Ma along the NQOB. The initial oceanic subduction may have occurred prior to ca. 526 Ma. An intense and multiple-stage extension developed at ~420–350 Ma in the northern part of the NQOB following the orogenic collapse. Lithospheric delamination and subsequent mafic magma underplating may be the main geodynamic mechanism resulting in the uprooting of the continental crust and ore mineralization in response. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS) technique has attracted more and more interest for specific identification of chemicals. However, the low selectivity and repeatability of the SERS-based technique limit its wide use in testing complex real-world samples containing various analytes. These shortcomings can be overcome by combining the SERS technique with molecularly imprinted polymers (MIPs), which can provide a highly selective SERS measure. This review firstly summarises the principles and preparation methods of MIPs and background knowledge of the SERS technique. Then, different MIPs-SERS preparation approaches and nanocomposites are highlighted. Finally, the main challenges and future efforts in developing MIPs-SERS sensors for detecting environmental contaminants are discussed. [ABSTRACT FROM AUTHOR]

The performance of offshore wind turbine supported with different configurations of Tension-leg-platform (TLP) are studied for vertical plane motion responses (surge, heave, and pitch) along with the side-to-side, fore–aft, and yaw tower base bending moments. The long-term distribution is carried out using the short-term floating wind turbine responses based on Rayleigh distributions and North Atlantic wave data. The long-term response analysis is performed for the 5 MW TLP-type offshore wind turbine. The study aims at predicting the most probable maximum values of motion amplitudes that can be used for design purposes. The transfer functions for surge, heave and pitch motions of the floater are obtained using the FAST code. The performance of floating structure in the long-term analysis not only depends on the transfer functions but also on the careful selection of design wave spectrum model. Among different theoretical design wave spectrum models, three models are chosen that closely represents the sea states and the response spectrums are computed for these models. As the nature of the response spectrum of the floating structure is analogous with the input wave spectrum model, it can be assumed to have the same probabilistic properties and modeled as a stationary stochastic process. The long-term probability distributions for TLP-type floater configuration for surge, heave and pitch motion amplitudes along with the tower base bending moments are used for design purposes, so as to guarantee the safety of the floating wind turbines against overturning/capsizing in high waves and wind speed. The calculation of the long-term distribution using FAST will help in the preliminary analysis of the performance of floaters in the study of wave-induced response of floaters. [ABSTRACT FROM AUTHOR]

Study of the factors controlling lacustrine source rock deposition is critical to predict potential source rocks and discover hydrocarbon reserves. Tectonic controls on source rock deposition have been a major research focus in recent decades. In this study, we integrated geochemical, geophysical, and microfossil data to investigate the effect of tectonic movements on lacustrine source rock deposition of the Wenchang Formation in Huizhou Sag, Pearl River Mouth Basin, southern China. Geochemical, geophysical, and microfossil analyses suggest that the lacustrine source rocks are characterized by high total organic carbon (TOC) contents, type I and type II1–2 kerogen, which primarily originated from aquatic organic matter (OM), and a peak oil-generation thermal maturity stage. Rift-related faults controlled the formation and distribution of two types of half-grabens in the Wenchang Formation. Synsedimentary faults created a large amount of accommodation space, making the half-grabens under-filled. Under warm and humid climatic conditions, plankton were abundant and organic matter supply was sufficient in the half-grabens of Huizhou Sag during the deposition of Wenchang Formation. Maximum flooding surfaces (mfs) created high accommodation spaces and strongly reducing conditions, which are favourable for organic-rich lacustrine source rock preservation. Source rocks close to the depocentre and slope of the half-grabens have high TOC contents. The depositional environment (i.e. the stable highly reducing conditions) of the lacustrine source rock was largely controlled by tectonics, therefore faulting activities were considered as the most important factor controlling the occurrence of lacustrine source rock. Models of lacustrine source rock deposition were established for the Wenchang Formation in the half-grabens using a multiple analysis model. This model is also suitable for investigating the deposition of other lacustrine source rocks in half-grabens with tectonic and climatic conditions similar to those of the South China Sea Basin. [ABSTRACT FROM AUTHOR]

Four new diarylheptanoids, (1S, 3R, 5R, 6R)-1, 5-epoxy-3, 6 dihydroxy-1-(4-hydroxy-3, 5-dimethoxyphenyl)-7-(4-hydroxy-3-methoxyphenyl) heptane (1), (1R, 3R, 5S)-1, 5-epoxy-3-acetoxy-1-(4, 5-dihydroxy-3-methoxyphenyl)-7-(3, 4- hydroxyphenyl) heptane (2), (3R, 5S, 6R, 7S)-3, 6-epoxy-7-hydroxyl-1-(4-hydroxyphenyl)-7-(3-methoxy-4-hydroxyphenyl) heptane (3), (E)-3-keto-1-(3-methoxy-4-hydroxyphenyl)-7-(4, 5-dihydroxy-3-methoxyphenyl)-4- heptene (4), were isolated from Rhizoma Zingiberis, and their structures were determined based on HR-ESI-MS and extensive spectroscopic techniques (UV, IR, 1D-NMR and 2D-NMR). Compounds 1–4 exhibited no cytotoxicity against HepG2 cell lines. [ABSTRACT FROM AUTHOR]

Radial-flow membrane chromatography is widely used for biopharmaceutical purification, particularly for separations carried out in the flow-through mode. In this article, we propose laterally fed membrane chromatography (LFMC) as an alternative to radial-flow membrane chromatography. LFMC has already been shown to be suitable for carrying out fast, high-resolution separations. In this study, we compare the performance of a radial-flow cation exchange membrane device with its equivalent LFMC device for flow-through separation of SP1, a recombinant protein that is currently under development by Sanofi Pasteur as a vaccine candidate. The flow-through of SP1 was monitored by UV absorbance while the breakthrough of the impurities such as host cell proteins was measured by analysing collected samples by Western blotting followed by densitometric scanning. The results obtained clearly demonstrated multiple-attribute superiority of the LFMC device in the above separation. [ABSTRACT FROM AUTHOR]

In the present work, the machinability of nickel–titanium (Nitinol) shape memory alloy has been discussed. Nitinol is known as a difficult-to-machine alloy due to its high hardness, which requires a large amount of cutting force, resulting in high rate of tool wearing. Therefore, researchers have made an effort to ameliorate the machinability of this material to achieve a finer surface quality. The previous studies found that the cutting speed will remarkably influence the surface properties of machined nickel–titanium alloy in turning process. Tool wear and cutting force are at minimum values in a particular range of cutting speeds so that it leads to diminishing machining barriers such as burr formation and chip-breaking. Lower cutting force and consequently lower temperature and stresses in the machining process improve the mechanical properties as well as reducing hardness, distortion, and residual stress. The machining process was optimized by applying a numerical approach through ANSYS/LS-DYNA R15 software. The obtained results demonstrated the optimum cutting speed in the machining process, which are in good agreement with experiments. [ABSTRACT FROM AUTHOR]

The Geza Andean-type arc is located in the southwestern Sanjiang tectonic belt (i.e. Jinsha, Lancang, and Nujiang River) of SW China, which is a product of the subduction of the Garzê–Litang oceanic crust beneath Zhongdian landmasses in the Late Triassic (235–204 Ma). The Geza Andean-type arc is an important belt of Cu-rich polymetallic mineralization that was recently discovered in China. Prolonged regional tectono-magmatic activity and several episodes of rich mineralization throughout the tectonic evolution of the Andean-type arc produced the super-large Pulang porphyry Cu deposits, the large Xuejiping porphyry Cu deposits, and the large Hongshan skarn-porphyry Cu polymetallic deposits. Here we report new LA-ICP-MS zircon U–Pb age of Songnuo and Qiansui intrusive rocks, and whole-rock major and trace element compositions of the Late Triassic mineralized porphyries from Geza in this region. Zircon U–Pb dating of the Qiansui quartz diorite porphyrite revealed a crystallization age of 220.3 ± 0.66 Ma, for the Songnuo quartz monzonite porphyry, a crystallization age of 204.7 ± 0.72 Ma. The Geza Andean-type arc granitic belt can be divided into three porphyry subzones based on the stage of Andean-type arc orogenic development and the distribution, composition, and geochemical characteristics of the intrusive rocks. Lithogeochemical characteristics show that the porphyry and Andean-type arc granite are of the same rock series (high-K calc-alkaline) and genetic type (I-type granite). The trace element geochemistry of these rocks is similar to that of Andean-type arc granite, which is enriched in Ba, Rb, La, Hf, chalcophile elements (Cu, Pb), and siderophile elements (Mo, Ni), and depleted in Nb, Ta, P, and Ti. In the Geza Andean-type arc, similarities in the major element, REE, and trace element compositions between porphyry and local acidic volcanic rocks suggest that they have the same or similar magmatic source rocks. The petrological characteristics of granite in the Geza Andean-type arc are similar to those of adakitic rocks, and the formation of porphyry and porphyry-related deposits resulted from magmatic hydrothermal fluids that originated in the upper mantle and lower crust. The porphyry Cu mineralization was probably produced from the accumulation and migration of ore-forming hydrothermal fluids and the resultant alteration of host rocks. [ABSTRACT FROM AUTHOR]

This paper deals with the machinability of nickel-based superalloys using abrasive water jet machining process. The machining studies were carried out with three different parameters such as water jet pressure, traverse speed of jet nozzle, and standoff distance at three different levels. The performances of the process parameters are evaluated by measuring difference in kerf width, kerf wall inclination, and material removal rate (MRR). Further, the surface morphology and material removal mechanisms are analyzed through scanning electron microscope (SEM) images. It is found that water jet pressure is the most influencing factor related to surface morphology and surface quality. [ABSTRACT FROM AUTHOR]

TiB2 particle-reinforced copper matrix composite is electroformed in copper sulfate on stainless steel plate. The impact of the particle content in electroforming solution on the surface morphology, hardness, and electrical conductivity of the electroformed composite are studied, and the influence of electroforming current density on the effective content of particles in the composite is also analyzed. The results show that when the content of particles in electroforming solution is 25 g/L, the current density is 4 A/dm2, particles in the electroformed composite are well-distributed, and the average grain diameter can be reduced to 20 µm. The microhardness of Cu/TiB2 composite reinforced by particles with diameter of 3 µm is 25% higher than that of electroformed copper, and its conductivity remains 86% of the copper. [ABSTRACT FROM AUTHOR]

The fluorescent sensor (3) based on the 1,3-alternate conformation of the thiacalix[4]arene bearing the coumarin fluorophore, appended via an imino group, has been synthesised. Sensing properties were evaluated in terms of a colorimetric and fluorescence sensor for Zn2+and F−. High selectivity and excellent sensitivity were exhibited, and ‘off-on’ optical behaviour in different media was observed. All changes were visible to the naked eye, whilst the presence of the Zn2+and F−induces fluorescence enhancement and the formation of a 1:1 complex with3. In addition,3exhibits low cytotoxicity and good cell permeability and can readily be employed for assessing the change of intracellular levels of Zn2+and F−. [ABSTRACT FROM AUTHOR]

A series of milling aerospace material Inconel 718 experiments were conducted with a sialon ceramic tool to investigate chip evolution, cutting force, and tool wear at different cutting speeds. Round inserts were used at ultra-high-speeds under dry cutting conditions. A scanning electron microscopy and an optical microscope were used to observe the worn surfaces and to reveal the wear mechanisms of the inserts. The experiment results showed that the macroscopic shape of the chips was small scraps and fan-shaped. With the increase in the cutting speed, the plastic deformation of the chips was increasingly serious. The minimal average cutting forces were obtained atvc = 700 m/min. The rise of cutting temperature was resulted from the increase in cutting deformation work and friction work with cutting speed. The combined effect of thermal stress and mechanical stress contributed to the tool chipping, flaking, microcrack propagation, abrasion, and adhesion which were the primary reasons of the sialon ceramic tool wear. [ABSTRACT FROM PUBLISHER]

In machining titanium alloys, due to the low thermal conductivity and high chemical activity of titanium alloys, tool wear is serious and processing efficiency is very low. To avoid the effects of impurities, which were brought by the cutting fluid, the uncoated cemented carbide tool (WC-Co), which was suitable for cutting titanium alloys, was used for the experiments of dryturning titanium alloy Ti-6Al-4V. A scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectrometer (EDS) was used to analyze toolwear mechanism. Based on analyzing the friction characteristic of tool-chip interface, toolwear mechanism was also studied and a physical evolution model of tool wear was established. The results showed that there existed serious adhesion, diffusion and oxidation at tool-chip interface and increasing cutting speed accelerated their occurrence. The physical evolution of tool wear behavior can reflect the loss process of tool material very well. [ABSTRACT FROM AUTHOR]

The reactions of Zn(II), Mn(II), and Ni(II) acetates with 1-picolinoyl-4-phenyl-3-thiosemicarbazide (Hppts) yielded [Zn(ppts)2]·CHCl3(3), [Mn(ppts)2]·THF (4), and [Ni(ppts)2]·THF (5), respectively, but HgCl2gave a cyclized product N-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole-2-yl-amine (2). The treatment of Hppts with conc. H2SO4formed N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-yl-amine (1). Hppts is a nonfluorescent material, but3,4and the cyclized products 1,3,4-oxadiazole/1,3,4-thiadiazole are fluorescent. The cyclized ligand N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-amine (1) formed [Zn(2-Hppt)2(OAc)2] (6) and [Cd2(2-Hppt)2(OAc)2(μ-OAc)2] (7) in which Cd(II) has a binuclear acetate-bridged seven coordinate pentagonal bipyramidal geometry. Complex7is also a fluorescent material with maximum emission at 425 nm at an excitation wavelength of 254 nm. [ABSTRACT FROM PUBLISHER]

Fumonisin B1(FB1) is a secondary metabolite produced byFusarium verticillioidesorFusarium proliferatum, which present in food and feed. It causes hazardous effects on human and animal health. A monoclonal antibody (mAb) against FB1was produced and a simple, reliable and sensitive, competitive, indirect enzyme-linked immunosorbent assay (ci-ELISA) for detection of FB1was developed and the experiment conditions were optimized. The coating concentration of FB1-ovalbumin (FB1-OVA) was 500 ng mL−1, the action concentrations of anti-FB1mAb and goat anti-mouse IgG were 1.28 × 104and 1:5000, respectively. The 50% inhibitory concentration (IC50) was 11 ng mL−1, with a detectable range of 1.25–250 ng mL−1, and a limit of determination (LOD) of 1.15 ng mL−1. The cross-reactivity (CR) of the antibody against fumonisin B2(FB2) was 60.4, and <1% against deoxynivalenol (DON), aflatoxin B1(AFB1), ochratoxin A (OTA) or zearalenone (ZEN). In spiked samples (250 ng g−1, 500 ng g−1, 1000 ng g−1), the mean recoveries ranged from 86.7 ± 5% to 102 ± 4%, and the coefficient of variation (CV) ranged from 3% to 10%. A survey of 96 corn samples from Bozhou, Fuyang, Bengbu, and Hefei, in Anhui province, China, was performed. Frequencies of FB1contamination were 83.3%, 95.8%, 20.8% and 91.7%, and the mean concentrations of positive samples were 0.702 μg kg−1, 0.883 μg kg−1, 0.074 μg kg−1, and 0.276 μg kg−1, respectively. The results of this study suggest that the ci-ELISA developed in this study can be used to identify FB1in corn, furthermore, further study is needed to investigate FB1contamination in food and feed to prevent its harmful health effects. [ABSTRACT FROM PUBLISHER]

Inconel 718 superalloy has wide applications in several industries due to its excellent mechanical properties. However, it is very difficult to machine using conventional cutting and grinding because of its high strength at elevated temperatures. Electrical discharge machining (EDM) is an alternative competitive process to machine Inconel alloys by electrical erosion. However, machinability and surface characteristics of EDMed Inconel surfaces are poorly understood. This study focuses on the machining characteristics of Inconel 718 by Wire-EDM and Sinking-EDM with a new Cu-SiC electrode, respectively. Material removal efficiency, surface roughness, surface topography, surface alloying, and electrode wear have been characterized. It is found that the high toughness of Inconel 718 would be the major contributing factor to the absence of microcracks on the EDMed surface. The new fabricated Cu-SiC electrode for Sinking-EDM has better performance in terms of material removal rate (MRR), surface roughness, and electrode wear. The higher melting temperature and fine microstructure of SiC contribute to the lower electrode wear of the new Cu-SiC electrode than the traditional Cu electrode. [ABSTRACT FROM PUBLISHER]

Two new coordination polymers [Mn(Hoba)2(bib)2]n(1) and [Mn (bda) (bib)0.5]n(2) [H2oba = 2-(3-carboxyphenoxy)benzoic acid, H2bda = benzophenone- 2,4′- dicarboxylic acid and bib = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene] were synthesized under hydrothermal conditions. Structure determination revealed that the complex 1 is a two-dimensional network—which further assembled into a three-dimensional framework via the intermolecular interactions. Complex 2 displays a two-dimensional layer structure based on the dinuclear Mn(II) units. [ABSTRACT FROM PUBLISHER]

This article describes a methodology based on force distributions for predicting cutting forces in side milling 7075-T651 aluminum. The methodology includes a practical mechanism for gathering experimental data. Milling forces on each disc are measured by experimentally dividing the cutter into discs for determining the milling coefficients. Force distributions are characterized as functions of cutting and edge forces, including cutter geometry and cutting parameter effects. In contrast to previous researches, the coefficients are determined considering relations between load and shear. Owing to its high performance, this methodology can be effectively used to improve machining accuracy in side milling. [ABSTRACT FROM AUTHOR]

Two new coordination polymers, [Zn(BDC)(BPMP)]n(1) and [Zn(PTA)(BPMP)]n(2) (H2BDC = isophthalate, H2PTA = p-Phthalic acid and BPMP = 1,4-bis (3-pyridylmethyl)piperazine), have been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction, IR, and EA. Complex 1 shows the two-dimensional (2D) layer structure. The 2D layers of 1 are further linked into three dimensional (3D) supramolecular networks by π…π stacking interactions. Complex 2 exhibits a 3D dia topological net. [ABSTRACT FROM PUBLISHER]

The zinc(II) and nickel(II) complexes of glycine–vanillin Schiff base were synthesized by one-step solid–solid reaction at room temperature. The composition and structure of the complexes were characterized by elemental analyses, Fourier transform infrared spectra (FTIR), X-ray powder diffraction (XRD), and thermogravimetry and differential scanning calorimetry (TG–DSC). The crystal structure of the complexes belongs to monoclinic system with the lattice parameters:a= 0.6807 nm,b= 1.3818 nm,c= 1.2011 nm,β= 95.80° for [Zn(C10H9O4N)(H2O)3], anda= 0.7457 nm,b= 1.3331 nm,c= 1.2560 nm,β= 91.89° for [Ni(C10H9O4N)(H2O)3]·1.5H2O. The experimental results indicate that the zinc and nickel ions are all six-coordinated by imino nitrogen, carboxylic oxygen, and phenolic oxygen from the Schiff base ligand, and oxygen from three coordinated water molecules, respectively. The possible pyrolysis reactions in the thermal decomposition processes of the complexes and the experimental and calculated percentage mass loss are also given. The two complexes have the most intense antibacterial activities againstEscherichia coli. [ABSTRACT FROM PUBLISHER]

A novel complex, [(Cu2L4(CH3OH)(H2O)]·1/2CH3OH·H2O (HL = 2-furoic acid), was synthesized and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. The title complex crystallizes in monoclinic, space group P2(1)/c witha= 10.2035 (12) Å,b= 13.1875 (17) Å,c= 20.069 (3) Å,a= 90°,b= 90.1460 (10)°,g= 90°,V= 2700.4 (6) nm3,Z= 2,F(000) = 1332,S= 1.053,Dc= 1.612 g·cm−3,R1= 0.0664 ((I> 2σ(I)),wR2= 0.1772,μ= 1.648 mm−1. Theoretical study of the title complex was carried out by Density Functional Theory B3LYP method. CCDC: 921325. [ABSTRACT FROM PUBLISHER]

Experiments have been carried out to investigate the interfacial tension (IFT) and emulsification behaviors between Shengli crude oil and a novel organic alkali (OA). The dynamic IFT and minimum IFT are adopted to characterize the IFT behaviors; the microscopic method, Turbiscan stability index, separated water rate, and laser particle size analysis method are used to show the emulsification behaviors. The dynamic and minimum IFT both decrease continuously with the increase of OA concentration whether surfactant is added or not; because of the synergy of OA and surfactant, the minimum IFT will be reduced to the ultralow value. The synergy is also crucial for the crude oil emulsification. When OA and surfactant are used together, owing to the mosaic and cross-multiple adsorption of OA, surfactant and in situ soap at the interfacial film, the oil can be emulsified more easily, the quantity of emulsified droplets is higher, and the emulsion is more stable with OA concentration increases. The relationship of the minimum IFT and emulsification is investigated; it indicates that the emulsion stability improves, the degree of dispersed homogeneity of oil droplets increases, and the median diameter of emulsified oil droplets decreases with the decline of the minimum IFT. [ABSTRACT FROM AUTHOR]

A novel complex, [CdL2(CH3COO)2] (1), was synthesized and characterized by IR, elemental analysis, and X-ray diffraction single-crystal analysis. Its crystal structure was compared with a previously reported complex, [ZnL2(CH3COO)2] (2). Complex (1) crystallizes in orthorhombic, space group Pna2(1) witha= 8.8821 (7) Å,b= 27.480 (3) Å,c= 9.0267 (8) Å,α= 90°,β= 90°,γ= 90°,V= 2203.3 (3) nm3,Z= 4,F(000)= 1064,S= 1.087,Dx= 1.601 g·cm−3,R1= 0.0322,wR2= 0.0708,μ= 1.211 mm−1. Theoretical studies of complexes (1) and (2) were carried out by density functional theory (DFT) B3LYP method. CCDC: Complex (1): 886802, Complex (2): 901631. Supplemental materials are available for this article. Go to the publisher's online edition ofSynthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistryto view the supplemental file. [ABSTRACT FROM PUBLISHER]

A new zinc(ιι) coordination polymer with 2,5-thiophene dicarboxylic acid (H2tda) and 1,4-bis(2-methyl-1H-imidazol-1-ylmethy) benzene(bmib) has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction, IR, and EA. Complex [Zn2(tda)2(bmib)]n(1), is monoclinic, space groupC2/cwitha= 14.215 (2),b= 16.579(3),c= 14.711(3) Å,β= 90.823(6)°,V= 3467(2) Å3,Z= 8,Mr= 737.36,Dc= 1.413 g/cm3,F(000) = 1496andμ= 1.553 cm−1. The final refinement gaveR= 0.0535 andwR= 0.0682 for 3104 reflections withI> 2σ(I). X-ray diffraction analysis reveals that the title compound [Zn2(tda)2(bmib)]n(1) displays a twofold interpenetrating three-dimensional pcu network. Furthermore, the luminescent property of complex 1 is investigated, which demonstrates that [Zn2(tda)2(bmib)]n(1) may be a good candidate as a photoactive material. [ABSTRACT FROM AUTHOR]

Ternary complexes of copper(II) with 2-aminomethylthiophenyl-4-bromosalicylaldehyde (ATS) and some amino acids have been isolated and characterized by elemental analyses, IR, magnetic moment, molar conductance, UV–vis, mass spectra, and ESR. The proposed general formulas of the prepared complexes are [Cu(ATS)(AA)]·nH2O (where AA?=?glycine, alanine, and valine). The low molar conductance values suggest the non-electrolytic nature of the complexes. IR spectra show that ATS is coordinated to copper in a bidentate manner through azomethine-N and phenolic-OH. The amino acids also are monobasic bidentate ligands via amino and ionized carboxylate groups. The magnetic and spectral data indicate the square-planar geometry of Cu(II) complexes. The geometry of the Cu(II) complexes has been fully optimized using parameterized PM3 semiempirical method. The Cu–N bond length is longer than that of Cu–O in the isolated complexes. Also, information is obtained from calculations of molecular parameters for all complexes including net dipole moment of the metal complexes, values of binding energy, and lipophilicity value (logP). The antimicrobial activity studies indicate significant inhibitory activity of complex3against the selected types of bacteria. The mixed ligand complexes have also been studied in solution state. Protonation constants of ATS and amino acids were determined by potentiometric titration in 50% (v/v) DMSO–water solution at ionic strength of 0.1?M NaCl. ATS has two protonation constants. The binary and ternary complexes of copper(II) involving ATS and some selected amino acids (glycine, alanine, and valine) were examined. Copper(II) forms [Cu(ATS)], [Cu(ATS)2], [Cu(AA)], [Cu(AA)2], and [Cu(ATS)(AA)] complexes. The ternary complexes are formed in a simultaneous mechanism. The present paper reports on the synthesis, characterization, and the electronic absorption spectra of Cu(II) ternary complexes involving ATS-Schiff base, and some selected amino acids. The antibacterial, antifungal, and antitumor activities were investigated. The geometry of the studied Cu(II) complexes has been fully optimized using parameterized PM3 semiempirical method. Protonation and complex formation equilibria were investigated. [ABSTRACT FROM PUBLISHER]

The development of high-speed milling technology provides an effective processing method for titanium alloy curved surface with high quality, and the spindle speed is an important machining parameter for the high-speed milling of titanium alloy curved surface. The variation of the geometric features of the titanium alloy curved surface results in the sharp fluctuation of the cutting force as well as the vibration of machine tool, which not only makes a severe impact on the surface machining quality and the tool life but also greatly affects the efficiency of the high-speed milling. An experimental study is carried out to determine the spindle speed for high-speed milling of the titanium alloy curved surface based on the cutting force. The experimental results indicate that in high-speed milling process, the cutting force is associated with the geometric feature of the curved surface and the change of cutting force is relatively smooth when the spindle speed is in the range from 9000 to 13,000 rpm for the machining of titanium alloy curved surface. [ABSTRACT FROM AUTHOR]

Schiff bases obtained from 5-chlorosalicylaldehyde with cyclopropylamine, and 4-methoxysalicylaldehyde with cyclopentylamine, were used as ligands for Zn(II) resulting in two mononuclear zinc complexes, [Zn(SalPr)2] and [ZnI2(SalPt)2], where SalPr is 4-chloro-2-(cyclopropyliminomethyl)phenolate and SalPt is 2-(cyclopentyliminiummethyl)-5-methoxyphenolate. The detailed structures of the complexes were determined by single crystal X-ray crystallography. Coordination sphere of Zn(II) atoms in both complexes are slightly distorted tetrahedron. The cytotoxic property of the complexes was evaluated. [ABSTRACT FROM AUTHOR]

This article proposes a high current density electrical discharge milling for machining Inconel 718. The proposed power supply comprises a pulse generator with high voltage and a DC power source with high current. The pip graphite electrode and the workpiece are connected to the negative and positive poles of the power supply, respectively. Benefiting from efficient flushing and high current density, the maximum material removal rate (MRR) achieved 15,062 mm3/min with a relative electrode wear ratio (REWR) of 1.73%. The effects of peak current and injection flushing pressure on the MRR and REWR were investigated. Experiments showed little differences between the thickness of recast layer with the peak currents of 150 A and 920 A, and the thickness was less than 50 µm. It is also evident that the microcracks within the recast layer penetrated into the base material and propagated along the grain boundar. [ABSTRACT FROM AUTHOR]

In this work, we present a novel etching method to fabricate the superhydrophobic Al surfaces in a salt solution. Hierarchical rough structures composed of micrometer-scale pits, protrusions, and rectangle plateaus and nanometer-scale step-like structures are formed on the Al surfaces by the self-assembled primary cell assisted etching and the preferential corrosion of grain boundaries and dislocations. After fluoroalkylsilane modification, the superhydrophobic Al surfaces with a 166.4° water contact angle and a 1° rolling angle are obtained. The developed method does not use any strong acids and has a smaller harm to the environment and operators. [ABSTRACT FROM PUBLISHER]

A pair of stereoisomers of magnesium Schiff base complexes, [Mg(C18H16N3O2)2·2CH3OH]n(1) (C18H16N3O2: 2-acetylpyridine-l-tryptophan) and [Mg(C18H16N3O2)2·2CH3OH]n(2) (C18H16N3O2: 2-acetylpyridine-d-tryptophan), was synthesized and characterized by IR, UV, elemental analysis,1H NMR, and X-ray diffraction single crystal analysis. The analyses of the structures indicate that they all crystallize in the tetragonal crystal system, space groupP43212andP41212, respectively. The two magnesium complexes have similar crystal structures. Mg(II) is six-coordinate with two nitrogens from C=N, two nitrogens from pyridine, and two carboxylic oxygens in different ligands forming a distorted octahedral geometry. Through N–H···O intermolecular hydrogen bonds a 2-D layer structure was formed. The interaction between1and calf thymus DNA was also investigated by UV absorption spectra, fluorescence emission spectra and viscometry. The results indicate that1interacts with DNA very strongly (Kb = 2.01 × 107 L mol−1andKsq = 0.195). The nature of the binding seems to be mainly an electrostatic interaction between DNA and the magnesium complex. Other binding modes, such as hydrogen bonds, may also exist. [ABSTRACT FROM AUTHOR]

A new tridentate Schiff base, 5-bromosalicylaldehydeS-allylisothiosemicarbazone hydrobromide (H2L), and several new mononuclear complexes of copper(II) and molybdenum(VI) of this ligand with general formulas ([Cu(L)Im] (1)), ([Cu(L)NH3]·4H2O (2)), and ([MoO2(L)1-MeIm] (3), Imidazole: Im, 1-methylimidazole: 1-MeIm) were prepared and characterized by elemental analyses, IR, proton magnetic resonance Spectroscopy, and ultraviolet–visible techniques. The physico-chemical results suggested that the H2L coordinates in the dianionic tridentate form. Crystal structures of the Cu(II) complexes reveal a square planar configuration surrounded by the dianionic tridentate isothiosemicarbazone (ONN) and Im and NH3for1and2, respectively. The L2-, two oxo, and 1-methylimidazole are coordinated to molybdenum(VI) in a distorted octahedral geometry in3. Formation of pure metal oxide residues was confirmed by thermal degradation of the complexes. [ABSTRACT FROM AUTHOR]

[Cu(Sal-Gly)(Im)(H2O)] (1) and [Ni(Sal-Gly)(H2O)2] (2) (Sal-Gly = N-salicylideneglycinate) was synthesized and structurally characterized. 1 and 2 are one-dimensional chain coordination polymers. In 1, Cu(II) ion has a five-coordinated square-pyramidal geometry and is surrounded by two O and one N atoms from a tetradentate Sal-Gly dianion and one N atom from imidazole ligand and one O from adjacent Sal-Gly ligand. In 2, Ni(II) adopts six-coordinated distorted octahedral geometry and is surrounded by two O and one N atoms from a tetradentate Sal-Gly dianion, two O from two aqua ligands, and one O from adjacent Sal-Gly ligand. [ABSTRACT FROM AUTHOR]

Hybrid polymers, which form a combination of monomers with different reactive groups and curing mechanisms, synergistically combine the properties of the two constituent homopolymers. In this paper, polymer-dispersed liquid crystal (PDLC) films using epoxies / acrylates as hybrid polymer matrix components were prepared. The UV polymerisation temperature dependence of the microstructure and the electro-optical properties of PDLC films based on epoxies / acrylates hybrid polymer matrix had been studied. The electro-optical properties of PDLC films depend strongly on the liquid crystal (LC) domain size and morphology of PDLC films, which could be controlled by the polymerisation rate of the curable monomers and the diffusion rate of the LC molecules during the film preparation process. The polymerisation rate of the curable monomers and the diffusion rate of the LC molecules depend exponentially on the UV polymerisation temperature. Therefore, this research reports an example of methods to prepare PDLC films based on a hybrid polymer matrix and obtain PDLC films which possess good electro-optical properties. [ABSTRACT FROM AUTHOR]

The electric-field-driven liquid crystal lens (ELC) induces the lens effect by the spatially non-uniform distribution of the refractive index. A scheme to analyse the performance of the ELC lens for the lights of various incident angles is devised by the calculation of the phase through the ELC lens and the determination of light ray directions from these phases. The calculated results show that the ELC lens changes the incident light of the plane wave into a focused wave and the focal distance becomes shorter for larger incident angles. [ABSTRACT FROM AUTHOR]

A liquid crystal (LC) lens is used to change the propagating direction of the incident light at the lens-shaped boundary of two different media and shows strong dependence on the polarisation direction of the incident light. The performance of the cylindrical LC lens is investigated in the situation that the directions of the incident linear polarisation and the axis of the cylindrical lens are not parallel. Two LC cell configurations were considered where LC directors aligned twisted or homogeneously. In case of the twisted LC configuration, the polarisation direction of the propagating light follows the twist of the LC directors if the directions of the incident linear polarisation and the LC alignment on the side of the lower substrate are parallel. For these two configurations, the LC lens can control the propagating light in the LENS-ON state. In case of homogeneously aligned LC configuration, polar angle distributions of LC directors are not uniform due to the lens-shaped boundary. So in the LENS-OFF state where LC directors rotate under the driving voltage, a LC domain boundary may occur in some cases. [ABSTRACT FROM AUTHOR]

The heteroleptic nickel-2-aminopyridine complex of (acac) (CH3COO)Ni(2-NH2Py)2 (acac = acetylacetonate, 2-NH2Py = 2-aminopyridine) has been synthesized and structurally characterized. In the complex, an Ni2+ ion is six-coordinated by one acac− anion, one CH3COO− anion, and two 2-NH2Py molecules to form a distorted octahedron. Two molecules of 2-NH2Py coordinated to an Ni2+ ion in a cis-configuration. There are two intermolecular hydrogen bonds between NH2 group and the neighbor acetate, developing in two different directions to result in a 2D supramolecular network. [ABSTRACT FROM AUTHOR]

A novel 2-D organic–inorganic hybrid copper-yttrium heterometallic monovacant Keggin phosphotungstate derivative [Cu(dap)2]5.5[Y(α-PW11O39)2]·4H2O (1) (dap = 1,2-diaminopropane) has been hydrothermally synthesized by reaction of Na9[A-α-PW9O34]·7H2O, CuCl2·2H2O, YCl3 and dap and structurally characterized by elemental analysis, IR spectrum, UV spectrum, powder X-ray diffraction (PXRD), and X-ray single-crystal diffraction. 1 illustrates an interesting 2-D copper-yttrium heterometallic sheet architecture with a 5-connected topology built by 1:2-type [Y(α-PW11O39)2]11− subunits and [Cu(dap)2]2+ bridges. To our knowledge, 1 represents a rare 2-D organic–inorganic hybrid Keggin phosphotungstate-based transition metal and rare-earth heterometallic derivative. The photocatalytic measurements show that 1 can inhibit the photodegradation of rhodamine-B. [ABSTRACT FROM AUTHOR]

Improvement of dihydroxyacetone (DHA) production by mutagenesis of ion beam implantation and medium optimization using response-surface methodology (RSM) were investigated in this work. More than 1000 mutant strains were selected through a mutagenesis method using N+ ions implantation with a dose of 60 × (2.6 × 1013) ions/cm2 and energy of 10 keV. Several high-yield mutant strains were showed the potent application for DHA production and the genetically stable mutant strain G. oxydans ZJB09113 was selected for optimization of cultivation condition by RSM. The optimal medium for DHA fermentation is composed (in g/L) of yeast extract 4.88, CaCO3 2.00, and glycerol 52.86 mL/L (initial pH 4.89). The maximal DHA concentration of 40.0 g/L was achieved after 24 hr of shaken flask fermentation at 30°C with 150 rpm, and 196.3% increase in DHA production in comparison with unoptimized conditions. [ABSTRACT FROM PUBLISHER]

Transport phenomena through polymeric composite membranes depend on several complex factors, involving not only their chemical composition but also their microstructure. Due to the combination of mesomorphic and macromolecular behaviour, thermotropic liquid crystal polymers (LCP) may enhance the transport properties in membranes by improving parameters related to the order, orientation, connectivity and distribution of the different domains arising from phase separation. This paper provides an overview of some existing and potential applications of liquid crystals (LC) in polymeric membranes as effective structure-directing templates or as components providing a dynamic response to external stimuli. The first part is a description of the composition and phase behaviour of LCP containing ionic and ionogenic groups, the so-called liquid crystal ionomers (LCI). The second part is focused on the description of LCP and LCI used in transport applications, such as proton-conducting films in fuel cells, ionic polymer transducers and hydrogels. The paper highlights the relationships between the composition and the LC properties of the materials and their potential as membranes for ionic and solvent transport, with particular attention paid to covalently linked materials prepared by copolymerisation, due to their higher versatility and stability. [ABSTRACT FROM AUTHOR]

We report optical interferometric studies of a wedge-shaped nematic liquid crystal cell. Interference fringes were observed when a nematic liquid crystal cell was placed in one of the arms of Mach–Zehnder interferometer. In the case of homogenous gap cell, the fringe contrast remained unaffected on applying voltage. However, in the case of wedge-shaped cell, the fringe contrast was found to degrade under an applied electric (DC) field and it became poorer at higher voltages. At higher voltages the fringe contrast improved where complete switching occurred. The degradation in fringe contrast due to wedge-shaped cell structure might find applications for speckle reduction in future laser-based rear projection displays. [ABSTRACT FROM AUTHOR]

Electric field-driven liquid crystals (ELC) use the non-uniform distribution of LC directors and show strong dependence on the polarisation direction of the incident light. Phase changes by an ELC lens where LC directors are twisted are investigated. When the polarisation direction of incident light is parallel to the rubbing of the LC cell of the ELC lens on the side of the incident light, the polarisation direction of the propagating light follows the twist of the LC directors. Hence, outgoing light is still linearly polarised and its phase profile can be controlled to match that of a geometric cylindrical lens. [ABSTRACT FROM AUTHOR]

In this study, we have investigated newly synthesised chiral smectic A (SmA*) liquid crystals (LCs) with a lactic acid structure with polarised optical microscopy (POM). We started cooling from the clear point until a SmA* phase emerged as the temperature dropped to the range 55.7-88.6°C. At this point, the alignment of the LC molecules resulted in a homeotropic texture. To take advantage of this characteristic, we then mixed the SmA* LC into a negative dielectric anisotropy nematic-type liquid crystal (NLC)/photo-curable acrylic pre-polymer mixture system (the NLC mixture system) with photo-induced vertical alignment, to realise the vertical alignment effect among the NLC molecules. This multi-component LC mixture system gave rise to a special, unknown twist grain boundary AX (TGBAX*) phase with rather broad temperature range, which maintained its helix structure even after crystallisation. In addition, we also utilised the electrical field induced molecular tilt effect (the electroclinic effect) within the SmA* LC to improve the response time of the LC device and gray-scale capability of the NLC mixture system. We further observed this multi-component LC mixture system after ultraviolet light irradiation treatment with POM, to investigate the alignment of the LC molecules, device display and electro-optical properties. [ABSTRACT FROM AUTHOR]

In this study, we applied the non-contact photo-polymerisation method in fabricating pseudo-polyimide (PI) liquid crystal (LC) devices with vertical alignment copolymer films, in the hope of solving the problems associated with traditional rubbing alignment processes. We mixed different photo-polymerisation-type acrylic monomers and negative dielectric anisotropy LC at proper weight percentages, and induced phase separation behaviour between the photo-polymerisation-type acrylic monomers and the LC molecules in the LC mixture solution through ultra-violet light irradiation, thereby forming copolymer films with vertical alignment effects. We further conducted preliminary characterisation of the alignment mechanism, photo-polymerisation, etc., of the LC molecules and investigated their interactions with alkyl acrylic monomers with different carbon chain lengths (the analogue of alkyl side chains in traditionally used vertical alignment-type PI) and electro-optical properties such as the transmittance, contrast ratio, and response time. [ABSTRACT FROM AUTHOR]

Four laterally difluorinated phenyl tolane liquid crystals were synthesised and their physical properties evaluated. These compounds exhibit a fairly small heat fusion enthalpy (ΔH ∼ 12.56 kJ mol-1), which is favourable for mixture formulations. For comparison, four lateral difluoro cyclohexane tolane homologues are also studied. We doped 10 wt% of each compound into a commercial negative mixture N1 and measured the birefringence, visco-elastic coefficient and figure of merit. Birefringence varies very little between homologues, but the visco-elastic coefficient increases as alkyl chain length increases. The refractive indices of these guest-host mixtures at 1550 nm are also measured. [ABSTRACT FROM AUTHOR]

Dual frequency liquid crystals (DFLCs) provide a possibility to achieve sub-millisecond rise and decay times and are useful for various electro-optical devices. In most of DFLC mixtures, ester compounds are utilised in order to obtain a low crossover frequency. However, the ester linking group does not provide π electron conjugation so that the DFLC mixtures usually exhibit a limited birefringence (Δn < 0.3 at λ = 633 nm). For phase modulation a lower birefringence demands a thicker cell gap which, in turn, increases the response time and operating voltage. This problem becomes more severe as the wavelength increases. In this paper, we introduce a series of isothiocyanato phenyl tolane positive compounds with high birefringence and moderate dielectric relaxation frequency. The dielectric and electro-optical properties of these compounds are investigated. We also formulated a DFLC mixture using these new positive compounds which exhibits Δn = 0.39 at λ = 633 nm and 0.33 at λ = 1550 nm. [ABSTRACT FROM AUTHOR]

The 2-carboxybenzaldehyde-2,4-dinitrophenyl hydrazone (C14H10N4O6, H2L) was prepared by condensation of 2-carboxybenzaldehyde with 2,4-dinitrophenyl hydrazine in absolute alcohol. Thirteen novel complexes were synthesized from the reaction of H2L with RE(NO3)3· 6H2O(where RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb and Y) in methanol. Characterization by elemental analysis, molar conductivity, FT-IR, UV-Vis, FS and X-ray powder diffraction analysis shows that the composition formula of the hydrazone and complexes are C14H10N4O6 and RE(C14H9N4O6)(C14H8N4O6)· 4H2O, respectively. The thermal decomposition of thirteen complexes was studied by TG-DTG analysis and their apparent activation energies were calculated by Kissinger's and Ozawa's method. [ABSTRACT FROM AUTHOR]

We review the recent progress in developing high performance dual frequency liquid crystal (DFLC) materials. A new figure of merit is derived for evaluating the DFLC performance. The dielectric relaxation and electro-optical properties of several high performance compounds, which possess a positive dielectric anisotropy at low frequencies and a relaxation frequency in the kilohertz region, are presented. Potential applications of these compounds are discussed. Compounds with a negative dielectric anisotropy were also compared and discussed. Two experimental DFLC mixtures were demonstrated with one intended for room temperature operation and another for elevated temperature operation. [ABSTRACT FROM AUTHOR]

An experimental phase diagram for two types of nematic liquid crystals and their binary mixtures was established by polarised optical microscopy and differential scanning calorimetry methods. The mixtures comprised a tolane-base liquid crystal, 4-heptyl-3-fluoro-4-isothiocyanatotolane (7TOLF), and a biphenyl-base nematogen, 4-heptyl-3-fluoro-4-isothiocyanatobiphenyl (7BF). The static Kerr effect and third-order non-linearity were investigated for 7TOLF and 7BF and their nematic mixtures within the isotropic phase. Both the compounds have a positive and large Kerr constant. The second-order phase-transition temperatures, T*, were determined for these mixtures. The linear dependence of (T - T*)- 1 on the Kerr constant is found to be in good agreement with the predications of the Landau-de Gennes model. The third-order non-linear susceptibility,χ(3), values were determined for these mixtures. [ABSTRACT FROM AUTHOR]

Normal-mode polymer stabilised cholesteric liquid crystal (Ch-LC)/aerosil particles (APs) composites are prepared by photo-polymerisation of the photo-polymerisable monomer in the electrically induced homeotropically oriented cholesteric phase of a photo-polymerisable monomer/Ch-LC/APs mixture. On the application of an electric field, the composites can change from a light scattering state to a transparent state accompanied by the texture changing from a focal conic texture to an electrically induced homeotropic texture. Moreover, the process was greatly influenced by the addition of the APs. The focus of this study is on the effects of the APs on the electro-optical performance and the morphology of polymer network of the composites. The effect of the chiral dopant concentration on the electro-optical performance is also studied. [ABSTRACT FROM AUTHOR]