Long-period Gratings in-situ Sensing for Flow Monitoring in Liquid Composite Molding

Liquid composite moulding (LCM) processes are used to manufacture high quality and complex-shaped composite parts in the automotive, marine, aerospace and civil industries. On-line sensing plays an important role in controlling the quality of the final product in the LCM manufacturing environment. The long-period fiber grating (LPG) technology, a new real-time fiber optic sensor system, was developed to monitor the flow front progression. The sensor operation and characterization under various process conditions were discussed in detail. The experimental results showed that LPG sensors were robust and reliable to detect the arrival of resin at pre-selected locations in structures with low-medium fiber volume fraction; however were limited at different depths in structures with high fiber volume fraction.

Electrodeposition of iridium from composite ionic liquid

In order to study the electrodeposition process of iridium in composite ionic liquid, the effects of N, N-dimethylacetamide（DMAC） on the viscosity, conductivity and electrochemical stability of composite ionic liquid BMIC-BMIBF4, as well as the electrochemical behavior of Ir Cl3 in this system were studied. Iridium（Ir） coatings were deposited at different constant potentials and characterized by SEM and XRD. The results show that the addition of DMAC can evidently decrease the viscosity of the composite system, increase conductivity and improve electrochemical stability of the composite system. Cyclic voltammograms of a Au electrode illustrate that the process controlled by diffusion rate is irreversible with the average charge transfer coefficient of 0.170 and average diffusion coefficient of 1.096×10-6 cm^2/s. In addition, SEM image shows that Ir film deposited at the reduction peak potential is dense and even, while XRD pattern shows that Ir deposit is polycrystalline structure.

Microstructure and deposition mechanism of electrodeposited Cu/liquid microcapsule composite

The nanostructured copper/microcapsule containing liquid core materials composite（copper/liquid microcapsules composite） was prepared using direct current（DC） electrodeposition method.The surface morphology and microstructure of composite were investigated by means of scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and X-ray diffraction（XRD）.The results show that the microstructure of electrodeposited layer transformed from bulk crystal to nano structure because of the participation of microcapsules.The diameters of microcapsules and the copper grain sizes in the composite were 2？20 μm and 10？20 nm,respectively.In addition,the electrodeposition mechanism of composite in the deposition process followed electrochemistry theory,which was proved by the theoretical analysis result and the experiment results.Meanwhile,the co-deposition process model was presented.

CUTTING REGULARITY AND DISCHARGE CHARACTERISTICS BY USING COMPOSITE COOLING LIQUID IN WIRE CUT ELECTRICAL DISCHARGE MACHINE WITH HIGH WIRE TRAVELING SPEED

The analysis of cutting regularity is provided through using and comparing two typical cooling liquids. It is proved that cutting regularity is greatly affected by cooling liquid＇s washing ability. Discharge characteristics and theoretic analysis between two electrodes are also discussed based on discharge waveform. By using composite cooling liquid which has strong washing ability, the efficiency in the first stable cutting phase has reached more than 200 mm^2/min, and the roughness of the surface has reached Ra〈0.8 μm after the fourth cutting with more than 50 mm^2/min average cutting efficiency. It is pointed out that cutting situation of the wire cut electrical discharge machine with high wire traveling speed （HSWEDM） is better than the wire cut electrical discharge machine with low wire traveling speed （LSWEDM） in the condition of improving the cooling liquid washing ability. The machining indices of HSWEDM will be increased remarkably by using the composite cooling liquid.

Determination of Ten Kinds of Alpha-2 Agonists Residues in Animal Derived Food by UHPLC-Triple Quadrupole/Composite Linear Ion Trap Mass Spectrometry

[Objectives]The paper was to establish an ultra high performance liquid chromatography-quadrupole/linear ion trap complex mass spectrometry for the determination of 10 kinds ofα2-receptor agonists in animal derived food.[Methods]The samples were extracted with sodium carbonate buffer solution and ethyl acetate,and analyzed by mass spectrometry after solid phase extraction and high performance liquid chromatography separation.[Results]Ten kinds ofα2-receptor agonists showed a good linear relationship in the range of 1-100μg/mL,with the average recovery of over 69%and the relative standard deviation less than 8.32%.The detection limit of 10 kinds of α_(2)-receptor agonists was up to 1μg/kg.[Conclusions]The method has good selectivity and strong anti-interference ability,and can meet the requirements of 10 kinds ofα2-receptor agonists residues in animal derived food.

Draping Behavior of Carbon Non-Crimp Fabrics and Its Effects on Mechanical Performance of the Hemispherical Composites

In order to investigate the draping behavior of non-crimp fabrics（NCFs）, two types of carbon NCFs with tricot-chain stitches or chain stitches were formed on a hemispherical mould via a stretch forming process. The shear angle and forming defects of the fabrics were measured on the hemisphere, under different blank holder forces（BHFs）. The results showed that increasing BHF could enhance the shear angle slightly, reduce the asymmetry for the deformation of the fabrics, and change the main type of the process-induced defects. Besides, compression tests were performed on the corresponding composite components. By analyzing the change of fiber volume fraction and structural parameters of the textile reinforcements, the effects of draping behavior of NCFs on the mechanical performance of the composites were studied. The results reveal that draping process has distinguishable impacts on the mechanical properties of the final components, which is closely related to the stitching pattern of the NCFs.

Synthesis,characterization and application of PVA/ionic liquid mixed matrix membranes for pervaporation dehydration of isopropanol

In this study,polyvinyl alcohol(PVA)–ionic liquid(IL) membranes were prepared for the separation of isopropyl alcohol(IPA)–water azeotropic mixtures by pervaporation.PVA-IL composite membranes were prepared by simple solvent evaporation method using four ILs,viz.,1-n-butyl-3-methylimidazolium chloride(BMIMCl),1-hexyl-3-methylimidazolium chloride(HMIMCl),1-hexyl-3-methylimidazolium tetra fluoroborate(HMIMBF4) and 1-octyl-3-methylimidazolium chloride(OMIMCl).Three ILs were used to study the effect of alkyl chain on the pervaporation performance.The study had focused on the effect feed water concentration from 10%–40%and effect of feed temperature from 50–80°C.Physiochemical properties of all the membranes were studied using Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM) and contact angle measurement.The Arrhenius activation energies for permeation were estimated to be in the range 4–12 kJ·mol-1 from the temperature dependent permeation values.

INTERSECTION POINT RULE OF THE RETENTION VALUE AND MOBILE PHASE COMPOSITION OF THE HOMOLOGUES IN REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Based on the intersection point rule of the retention value and normal boiling point of homologues in reversed-phase high-performance liquid chromatography(RPLC), the intersection point rule of the retention value of homologues and mobile phase composition has been derived, and was testified by a lot of experimental data from the literature. With this newly proposed equation, we can use the retention value of the compound in one mobile phase composition to predict its retention value in any other mobile phase composition. For fourteen groups of homologues in five mobile phase compositions on five Kinds of columns, the overall average absolute error of 721 data sets is 2.8%.

Arbitrary skin metallization by pencil-writing inspired solid-ink rubbing for advanced energy storage and harvesting

The development of a durable metallic coating on diverse substrates is both intriguing and challenging,particularly in the research of metal-conductive materials for applications such as batteries,soft electronics,and beyond.Herein,by learning from the pencil-writing process,a facile solid-ink rubbing technology(SIR-tech)is invented to address the above challenge.The solid-ink is exampled by rational combination of liquid metal and graphite particles.By harnessing the synergistic effects between rubbing and adhesion,controllable metallic skin is successfully formed onto metals,woods,ceramics,and plastics without limitation in size and shape.Moreover,outperforming pure liquid-metal coating,the composite metallic skin by SIR-tech is very robust due to the self-lamination of graphite nanoplate exfoliated by liquid-metal rubbing.The critical factors controlling the structures-properties of the composite metallic skin have been systematically investigated as well.For applications,the SIR-tech is demonstrated to fabricate high-performance composite current collectors for next-generation batteries without traditional metal foils.Meanwhile,advanced skin-electrodes are further demonstrated for stable triboelectricity generation even under temperature fluctuation from-196 to 120℃.This facile and highly-flexible SIR-tech may work as a powerful platform for the studies on functional coatings by liquid metals and beyond.

Carbon fiber reinforced liquid crystalline elastomer composites:a dual exploration in strength augmentation and transformation flexibility through 4D printing

Liquid Crystal Elastomers(LCEs)are renowned for their reversible deformation capabilities.Yet,enhancing their mechanical strength while retaining such flexibility has posed a considerable challenge.To overcome this,we utilized 4D printing to develop an innovative composite of LCE with carbon fiber fabric(LCEC).This approach has notably increased the tensile strength of LCE by eightfold,all the while maintaining its exceptional capacity for reversible deforma-tion.By adjusting the alignment angle between carbon fiber and the LCE printing direction from 0°to 90°,the LCEC demonstrates an array of new deformation patterns,including bending,twisting,wrapping,and S-shaped transformations,which are distinct from pure LCE materials.Our study unveils that LCE composites exhibit deformation processes markedly different from their pure material counterparts,with the ability of pure LCE to sustain tensile strains exceeding 1900%.These findings,previously undocumented and unexplored,represent a substantial contribution to the field of smart materials.Employing finite element analysis,we explored the carbon fiber and LcE matrix dynamics,revealing bending mechanics in LCECs.This combined experimental and simulation approach yields crucial insights for crafting durable,high-strength LCECs with diverse deformational properties,advancing smart material technology.

Experimental Characterization by Fluorescence of Capillary Flows in the Fiber Tows of Engineering Fabrics

Liquid Composite Molding (LCM) is an increasingly used class of processes to manufacture high performance composites. In LCM, the fibrous reinforcement is first laid in a mold cavity. After closure of the mold or covering of reinforcement with a plastic bag, a polymer resin is either injected or infused under vacuum through the fiber bed. The engineering fabrics commonly used in LCM possess generally dual scale architecture in terms of porosity: microscopic pores exist between the filaments in the fiber tows, while macroscopic pores appear between the tows as a result of the stitching/weaving fabrication process. On a microscopic scale, capillary flows in fiber tows play a major role on the quality of composites made by resin injection through fibrous reinforcements. In order to better understand the mechanisms that govern the impregnation of fibrous reinforcements in LCM, a study of wicking behavior is carried out in fiber tows. The experimental approach is based on capillary rise experiments, which are less expensive and time-consuming than other more standard characterization techniques often used in porous media. In addition, it allows gathering representative data on the wicking properties of fiber tows as a function of their morphological characteristics such as micro-porosity, total cross-section area, specific surface area, filament diameter and packing configuration. The morphological properties of the fiber tows will also be characterized by other standard experimental methods in order to compare with the results obtained by capillary rise experiments. These standard methods include gravimetry for the micro-porosity and fiber mass density, microscopic analysis to measure the filament diameter, cross-section area and packing configuration of the filaments and capillary flow porometry to evaluate the equivalent pore diameter. The capillary rise method has already been used not only in Soil Mechanics, but also to characterize engineering textiles used in high performance composites. Such experiments are not easy to perform, because of technical difficulties such as textile geometrical alteration during testing, changes in fluid properties due to solvent evaporation and inaccurate observation of the progression of the capillary front (fading). To circumvent these problems, a monitoring technique based on fluorescent dye penetration inspection (DPI) and CCD image acquisition is proposed in this investigation. Visual monitoring of the capillary front is coupled with real-time fluid mass acquisition using a high resolution balance. Experimental observations on the height of the capillary front and the fluid mass absorbed by the fiber tows can be analyzed by four imbibition models. These models consider the evolution of the capillary height with (model I) or without gravity (model II) and of the fluid mass absorbed by capillary effect with (model III) or without gravity (model IV). The models without gravity will be used on short imbibition distances to derive the microscopic properties of fiber tows from the experimentally observed evolutions of the capillary height and the fluid mass absorbed by capillarity. After describing the new capillary rise setup devised for the fiber tow experiments, a set of experiments is carried out to characterize the properties of the fiber tows and investigate the wicking phenomena along the warp and weft directions. The consistency of this approach is compared with more standard methods. At the same time, the impact of fiber sizing on the tow wicking behavior is investigated. Note that experimental evaluations of tow permeability can also be derived from this approach. The results compare well with permeability predictions based on Blake-Kozeny-Carman models. In the future, it will be possible to apply the same experimental approach to engineering fabrics. Indeed, a comprehensive wicking characterization of fibrous reinforcements is expected to provide useful information in order to evaluate the optimal processing conditions of high performance composites fabricated by Liquid Composite Molding.

Programming Shape-Morphing Behavior of Zwitterionic Polymer/Liquid Crystal Composite with Humidity-responsive Self-healing Performance

In this study,a zwitterionic polymer/liquid crystals composite film with programming shape-morphing behavior and humidityresponsive self-healing performance was prepared by blending a zwitterionic polymer and liquid crystalline azobenzene compound in solution,followed by film-forming in a mold without tedious or multistep synthetic route.The as-obtained zwitterionic polymer/liquid crystal composite film exhibited programming shape-morphing behavior under different stimuli.In this process,the temporary shape of the composite film was memorized after the removal of the stimuli.Such characteristics would fit the requirements of intelligence and energy-saving for stimuliresponsive shape-changing materials.Moreover,the composite film showed humidity-responsive self-healing performances under wet conditions at room temperature.In summary,the simple design and preparation route of the zwitterionic polymer/liquid crystal composite film with programming shape-morphing behavior and mild condition-responsive self-healing performance look promising for the fabrication and practical application of novel photo-driven devices and soft robotics.

A Luminescent Dicyanodistyrylbenzene-based Liquid Crystal Polymer Network for Photochemically Patterned Photonic Composite Film

A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network（LCN） was fabricated by using a silica colloidal crystal as a template. The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties, respectively. A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN. More importantly, the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation. On the basis of this effective phototuning process, microscopic patterning of photonic film was developed under both fluorescence mode and reflection mode. The work demonstrated here provides a new route to construct photo-responsive photonic film.

Recent research progress on quasi-solid-state electrolytes for dye-sensitized solar cells

Dye-sensitized solar cells （DSSCs） are the most promising, low cost and most extensively investigated solar cells. They are famous for their clean and efficient solar energy conversion. Nevertheless this, long-time sta- bility is still to be acquired. In recent years research on solid and quasi-solid state electrolytes is extensively in- creased. Various quasi-solid electrolytes, including composites polymer electrolytes, ionic liquid electrolytes, thermoplastic polymer electrolytes and thermosetting polymer electrolytes have been used. Performance and stability of a quasi-solid state electrolyte are between liquid and solid electrolytes. High photovoltaic performances of QS-DSSCs along better long-term stability can be obtained by designing and optimizing quasi-solid electrolytes. It is a prospective candidate for highly efficient and stable DSSCs.

Enhancement of Mechanical Properties of Natural Rubber with Maleic Anhydride Grafted Liquid Polybutadiene Functionalized Graphene Oxide

An effective procedure has been developed to synthesize the functionalized graphene oxide grafted by maleic anhydride grafted liquid polybutadiene（MLPB-GO）. Fourier transform spectroscopy and X-ray photoelectron spectroscopy indicate the successful functionalization of GO. The NR/MLPB-GO composites were then prepared by the co-coagulation process. The results show that the mechanical properties of NR/MLPB-GO composites are obviously superior to those of NR/GO composites and neat NR. Compared with neat NR, the tensile strength, modulus at 300% strain and tear strength of NR composite containing 2.12 phr MLPB-GO are significantly increased by 40.5%, 109.1% and 85.0%, respectively. Dynamic mechanical analysis results show that 84% increase in storage modulus and 2.9 K enhancement in the glass transition temperature of the composite have been achieved with the incorporation of 2.12 phr MLPB-GO into NR. The good dispersion of GO and the strong interface interaction in the composites are responsible for the unprecedented reinforcing efficiency of MLPB-GO towards NR.

A review of numerical analyses and experimental characterization methods for forming of textile reinforcements

The forming of textile reinforcements is an important stage in the manufacturing of textile composite parts with Liquid Composite Molding process.Fiber orientations and part geometry obtained from this stage have significant impact on the subsequent resin injection and final mechanical properties of composite part.Numerical simulation of textile reinforcement forming is in strong demand as it can greatly reduce the time and cost in the determination of the optimized processing parameters,which is the foundation of the low-cost application of composite materials.This review presents the state of the art of forming modeling methods for textile reinforcement and the corresponding experimental characterization methods developed in this field.The microscopic,mesoscopic and macroscopic models are discussed.Studies concerning the simulation of wrinkling are also presented since it is the most common defect occurred in the textile reinforcement forming.Finally,challenges and recommendations on the future research directions for textile reinforcement modeling and experimental characterization are provided.

Estimating the Parental Magma Composition and Temperature of the Xiaohaizi Cumulate-Bearing Ultramafic Rock: Implication for Magma Evolution of the Tarim Large Igneous Province, Northwestern China

The ultramafic dikes in the Tarim large igneous province（Tarim LIP）, exposed in the Xiaohaizi area in the northwestern Tarim Basin of northwestern China, have porphyritic textures, and the olivine and clinopyroxene are as the major phenocryst phases. The groundmass therein consists of clinopyroxene, plagioclase and Fe-Ti oxides, with the cryptocrystalline texture. The olivine phenocrysts in one typical ultramafic dike have Fo（Mg/（Mg＋Fe）） numbers ranging from 73 to 85, which are not in equilibrium with the olivine（Mg# of 89） from the host rock crystalized. Combined with microscope observation, both the olivine and clinopyroxene phenocrysts as well as some Fe-Ti oxides in the ultramafic rock are accounted as cumulates. The liquid（parental magma） composition of SiO2 of 45.00 wt.%–48.82 wt.%, MgO of 9.93 wt.%– 18.56 wt.%, FeO of 5.85 wt.%–14.17 wt.%, CaO of 7.54 wt.%–11.52 wt.%, Al2O3 of 8.70 wt.%–11.62 wt.% and TiO2 of 0.00 wt.%–3.43 wt.% in the Xiaohaizi ultramafic rock was estimated by mass balance, and the results show a reasonable liquid proportion in the cumulate-bearing ultramafic dike（ca. 45%–60% in the whole rock）. The estimated parental magma composition corresponds to a melting temperature of 1 300–1 550 oC, which is equal or higher than those of a normal asthenosphere mantle, supporting the involvement of a mantle plume. Combined with other previous studies, an evolution model for the formation processes of the Xiaohaizi ultramafic dike of the Tarim LIP is proposed.