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It is impossible to obtain the forming limit curve (FLC) by full zone hydraulic forming test under quasi-static (QS) condition since the liquid will leak from the notches of the specimen once the pressure increases. In this study, a novel method is proposed to investigate the frictionless full zone hydraulic FLC of AA5A06 under high strain rate (HSR) condition based on the impact hydroforming technology (IHF). It is found that the FLC is increased significantly by IHF compared with the quasi-static rigid punch (QS-R) forming and the quasi-static hydraulic (QS-H) forming. Differentiating with the QS-H, the increase amounts of FLC at the biaxial tension zone and the tension-compression zone are notably different for IHF. Additionally, the theoretical calculations of FLC is conducted by using M-K model combining with Hill48 anisotropic yield criterion under QS and HSR conditions. The results calculated by the M-K model reasonably agree with the ones obtained from experimentation under QS and HSR condition, and a higher initial thickness ratio is assigned for HSR considering the neck postponing effect of inertia.

BACKGROUND: Lumbar disc herniation (LDH) can cause lumbar nerve root compression, which can lead to denervated atrophy of paraspinal muscles theoretically, however, the conclusions of morphological alteration in multifidus with LDH remain controversial. Transforming growth factor-beta 1 (TGF-β1) plays an essential role in the development of tissue fibrosis and is a molecular marker in the study of muscle fibrosis, but no relevant studies on TGF-β1 expression in multifidus have been reported so far. This study is to observe altered morphology of multifidus in patients with LDH, and to explore the correlation between multifidus fibrosis and TGF-β1 expression. MATERIALS AND METHODS: 46 LDH patients with low back pain combined with unilateral leg radiation pain and/or numbness were selected. Patients were divided into four groups according to their medical histories. Group 1: medical history less than 6 months (15 cases); group 2: a medical history of 6–12 months (10 cases); group 3: a medical history of 12–24 months (13 cases); and group 4: medical history > 24 months (8 cases). Bilateral multifidus specimens were taken from compressed nerve root segments, and morphological changes in multifidus were determined. Multi-parameter changes in TGF-β1 expression in multifidus were observed by immunohistochemistry and immunofluorescence. RESULTS: HE staining showed that the cross-sectional area (CSA) of multifidus in the involved sides decreased and muscle fibers atrophied. Masson’s trichrome staining showed a decrease in the sectional area ratio of myofibers to collagen fibers in the involved side. In groups 1 and 2, there were no significant differences in the aforementioned parameters. In groups 3 and 4, statistically significant differences in the sectional area ratio of myofibers to collagen fibers in both sides were seen (P

Graphical abstract, Highlights • The mechanical behavior of AA2060 was investigated under HSR deformation and at room temperature. • A novel gripping method was designed to prevent the distortion of strain waves during HSR experiments. • The ductility of AA2060 was enhanced due to the adiabatic softening and inertia effect. • The fracture behavior of AA2060-T8 was changed from brittle to ductile behavior under HSR deformation. • Johnson-Cook constitutive model was modified to predict the dynamic flow behavior of AA2060-T8., Since AA2060-T8 was introduced in the past few years, investigating the mechanical response, fracture mechanisms, and anisotropic behaviour of AA2060-T8 sheets under high strain rate deformation has been crucial. Thus, uniaxial tensile tests were performed under quasi-static, intermediate, and high strain rate conditions using universal testing machines as well as split Hopkinson tensile bars. The experimental results showed that the ductility of AA2060-T8 sheets was improved during high strain rate deformation because of the adiabatic softening and the inertia effect which contribute to slow down the necking development, and these results were verified by the fracture morphologies of high strain rate tensile samples. Furthermore, the strain rate hardening influence of AA2060-T8 was significant. Therefore, the Johnson–Cook constitutive model was modified to consider the effects of both strain and strain rates on the strain hardening coefficient. The results obtained from the improved Johnson–Cook constitutive model are in remarkable accordance with those obtained from experimental work. Thus, the improved Johnson–Cook model can predict the flow behavior of AA2060-T8 sheets at room temperature over a wide range of strain rates. The results of the present study can efficiently be used to develop a new manufacturing route based on impact hydroforming technology (IHF) to manufacture sound thin-walled-complex shape components from AA2060-T8 sheets at room temperature.

Metal oxides have a large storage capacity when employed as anode materials for lithium-ion batteries (LIBs). However, they often suffer from poor capacity retention due to their low electrical conductivity and huge volume variation during the charge-discharge process. To overcome these limitations, fabrication of metal oxides/carbon hybrids with hollow structures can be expected to further improve their electrochemical properties. Herein, ZnO-Co3O4 nanocomposites embedded in N-doped carbon (ZnO-Co3O4@N-C) nanocages with hollow dodecahedral shapes have been prepared successfully by the simple carbonizing and oxidizing of metal-organic frameworks (MOFs). Benefiting from the advantages of the structural features, i.e. the conductive N-doped carbon coating, the porous structure of the nanocages and the synergistic effects of different components, the as-prepared ZnO-Co3O4@N-C not only avoids particle aggregation and nanostructure cracking but also facilitates the transport of ions and electrons. As a result, the resultant ZnO-Co3O4@N-C shows a discharge capacity of 2373 mAh g(-1) at the first cycle and exhibits a retention capacity of 1305 mAh g(-1) even after 300 cycles at 0.1 A g(-1). In addition, a reversible capacity of 948 mAh g(-1) is obtained at a current density of 2 A g(-1), which delivers an excellent high-rate cycle ability. Funding Agencies|National Natural Science Foundation of China [21601120, 1375111, 11575105]; Science and Technology Commission of Shanghai Municipality [17ZR1410500]; Key Natural Science Foundation of Anhui Provincial Education Commission [KJ2016A510]; Anhui Provincial Science Foundation for Excellent Youth Talents; Educational Quality and Innovation Project of Anhui Province [2015jyxm398]

Polyaniline was first confirmed as a dark green precipitate on an electrode during the electrochemical polymerization of aniline in 1862. Since then, scientists have been studying the kinetics and growth mechanisms of polyaniline through the electrochemical approach. Studies have shown that p-phenylenediamine, p-aminodiphenylamine, and other aromatic small molecules may serve as initiators for accelerating the polymerization reaction due to the autocatalytic effect of polyaniline. However, little research has been focused on the catalytic effects of introducing oligoanilines. In this paper, quantitative rate constants for the electrochemical polymerization of aniline in both HCl and acetonitrile/HCl solutions with 0.5 mol % of added oligoanilines including diphenylamine, N-phenyl-p-phenylenediamine, 1,4-phenylenediamine, N,N′-diphenyl-1,4-phenylenediamine, 4,4′-diaminodiphenylamine, and tetraaniline in both emeraldine and leucoemeraldine states are reported. Among all the rate constants, N-phenyl-p-phenyl...

Doping technology has been proved to be a productive strategy to realize the multi-functionality of materials. Herein, Ni doped SnO2 quantum dots (QDs) are fabricated through a convenient hydrothermal process. In the fabrication process, Vitamin C (VC) acts as a stabilizer to avoid the precipitating of Sn4+(Ni2+), and Na2CO3 serves as a precipitator to react with Sn4+(Ni2+) to produce Ni doped SnO2 QDs. The influence of the Ni doping amount on the photodegradation performance of SnO2 QDs is studied. It was found that the Ni doped SnO2 QDs with Ni/Sn atomic ratio of 1% display the best photocatalytic performace due to the following advantages: (1) the Ni doping can boost light-harvesting and narrow the band gaps of the SnO2 QDs; (2) the SnO2 QDs with ultra small particle size and large specific surface area can supply more reactive centers for photocatalytic reactions. The two important factors contribute to enhancing the photocatalytic performance of the 1% Ni doped SnO2 QDs. As a result, the 1% Ni doped SnO2 QDs photodegrade 91.5% Rhodamine B after being illuminated by solar light for 28 min, obviously surpassing that of their pure counterparts.

One-dimensional (1D) heterostructured photocatalysts with controllable texture properties and compositions have attracted increasing interest owing to their unique optical, structural, and electronic advantages. Herein, 1D Co3O4-SnO2 heteronanorods were rationally designed and synthesized through a facile solution-based approach. Benefiting from both of their heterostructural and compositional characteristics, the resulting Co3O4-SnO2 heteronanorods exhibit high photocatalytic performance for the degradation of Rhodamine B (RhB) under visible-light irridation. In particular, the photocatalyst with a Co3O4/SnO2 mass ratio of 1:1 provides the best photocatalytic performance, which can degrade 90% RhB within 120 min. Besides, several reaction parameters affecting RhB degradation, such as churning time, calcination temperature and pH value, are investigated in detail. The enhanced photocatalytic activity can be attributed to the broadening of absorption spectrum to visible-light regions and the efficient charge separation of photogenerated electron-hole pairs due to the formed p-n heterojunctions. The strategy reported here can be able to expand to fabricate other heterostructured photocatalysts for practical applications in the fields of photocatalysis, water splitting, and solar cells.

The alternately-organized poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) multilayer materials were prepared through layer-multiplying coextrusion. With the multiplication of layers, the thickness of each layer was reduced in proportion and the layer interfaces were enriched generating a broader and more continuous thermal transition temperature (Ttrans) from PVDF to PMMA layers as mapped by in-situ thermal analysis. The low-Ttrans side originated from the glass transition of PMMA, whereas the high-Ttrans side was dominated by the melting of PVDF crystals based on the heating curves of DMA and DSC. The dielectric spectroscopy and 2D-SAXS were performed and demonstrated that the compositional diffusion not only broadened the relaxation distribution of amorphous chains, but also strengthened the interaction between amorphous and crystalline domains. Therefore, a unique multilayer network, where the crystals in PVDF layers acting as physical networks connected the neighboring amorphous layers, was fabricated and its potential application in obtaining multi-shape memory effect (MSME) was disclosed for the first time. The results exhibited that the 1024-layer specimen owned a better triple- and quadruple-shape memory capacity than conventional blend which possessed the same compositions and a similar Ttrans range. The latter one even failed to successively memorize more than two temporary shapes. A possible mechanism was proposed through polarized IR and creeping-recovery measurements. Higher phase continuity which benefited for the stress transfer was revealed to play a significant role in strengthening the shape-fixing and -recovering ability during each shape-memory progress. Accordingly, a new physically-compounding strategy was addressed to achieve outstanding MSME for meeting complex demands in smart applications.

Construction of heterostructures with proper band alignment and effective transport and separation of photogenerated charges is highly expected for photocatalysis. In this work, Ni-doped SnO2-SnS2 heterostructures (NiSnSO) are simply prepared by thermal oxidation of Ni-doped hierarchical SnS2 microspheres in the air. When applied for the photodegradation of organic contaminants, these NiSnSO exhibit excellent catalytic performance and stability due to the following advantages: (1) Ni doping leads to the enhancement of light harvesting of SnS2 in the visible light regions; (2) the formed heterojunctions promote the transport and separation of photogenerated electrons from SnS2 to SnO2; (3) Ni-SnO2 quantum dots facilitate the enrichment of reactants, provide more reactive centers and accelerate product diffusion in the reactive centers; (4) the SnS2 hierarchical microspheres constituted by nanoplates provide abundant active sites, high structural void porosity and accessible inner surface to faciliate the catalytic reactions. As a result, the optimized NiSnSO can photodegrade 92.7% methyl orange within 80 min under the irradiation of simulated sunlight, greatly higher than those of pure SnS2 (29.8%) and Ni-doped SnS2 (52.1%). These results reveal that the combination of heteroatom doping and heterostructure fabrication is a very promising strategy to deliver nanomaterials for effectively photocatalytic applications.

Conjugated polyaniline has shown anticorrosive, hydrophilic, antibacterial, pH-responsive, and pseudocapacitive properties making it of interest in many fields. However, in situ grafting of polyaniline without harsh chemical treatments is challenging. In this study, we report a simple, fast, and non-destructive surface modification method for grafting tetraaniline (TANI), the smallest conjugated repeat unit of polyaniline, onto several materials via perfluorophenylazide photochemistry. The new materials are characterized by nuclear magnetic resonance (NMR) and electrospray ionization (ESI) mass spectroscopy. TANI is shown to be covalently bonded to important carbon materials including graphite, carbon nanotubes (CNTs), and reduced graphene oxide (rGO), as confirmed by transmission electron microscopy (TEM). Furthermore, large area modifications on polyethylene terephthalate (PET) films through dip-coating or spray-coating demonstrate the potential applicability in biomedical applications where high transparency, patternability, and low bio-adhesion are needed. Another important application is preventing biofouling in membranes for water purification. Here we report the first oligoaniline grafted water filtration membranes by modifying commercially available polyethersulfone (PES) ultrafiltration (UF) membranes. The modified membranes are hydrophilic as demonstrated by captive bubble experiments and exhibit extraordinarily low bovine serum albumin (BSA) and Escherichia coli adhesions. Superior membrane performance in terms of flux, BSA rejection and flux recovery after biofouling are demonstrated using a cross-flow system and dead-end cells, showing excellent fouling resistance produced by the in situ modification.

Exploring versatile strategies for microstructural evolution and surface modification are of fundamental importance in the development of advanced electrode materials. In this work, we report that electron-beam irradiation is a facile approach to perform surface modification for the ultrathin cross-stacked graphene aerogels loaded with SnO2 quantum dots, resulting in a remarkable modulation on the lithium storage performance. It is found that the as-synthesized SnO2/graphene aerogels composites irradiated at 280 kGy exhibit excellent high reversible lithium storage capacity, good rate capability and cycling stability, which retains a discharge capacity of 703 mAh g−1 after 50 cycles at 0.1 C rate. Microstructure analysis indicates that the enhanced electrochemical properties are mainly attributed to the exfoliation of graphene nanosheets, the increase of amorphization, disorder, defects and the removal of partial oxygen-containing functional groups on the surface of graphene nanosheets. The strategy presented here demonstrates that the electron-beam irradiation is a potential strategy to improve the electrochemical performance of graphene-based metal oxides.

Thermoplastic polyurethane (TPU)-based composites filled with carbon nanotubes (CNTs) and intumescent flame retardants (IFRs) were fabricated through melt compounding method. For comparison, TPU/IFR and TPU/CNT composites with different filling proportions were prepared, respectively. The results presented that the addition of 1 wt% CNTs and 10 wt% IFRs into TPU could achieve good flame retarding and electromagnetic interference (EMI) shielding properties simultaneously. With regard to flame retardancy, the compounding of CNTs and IFRs effectively suppressed the heat release rate and the UL-94 rating was upgraded to V-0 accompanied with prompt self-extinguishment and disappeared melt-dripping, which was equivalent to incorporate 20 wt% IFRs alone. However, the flame retardancy became deteriorated by loading more CNTs. It was revealed that the addition of CNTs could strengthen the carbonization effect of IFRs, but suppress their intumescent effect. Hence, a right amount of CNT loading was of critical importance to achieve synergistic effect with IFRs. Moreover, compared with the TPU/CNT system, the TPU/IFR/CNT system possessing the same CNT contents had a lower percolation threshold. When 1 wt% CNTs were introduced, the electrical conductivity was increased about two orders of magnitude and EMI shielding effectiveness was doubled in the presence of IFRs. The morphological observation and rheological analysis demonstrated that mixing with IFRs not only improved the dispersion of CNTs through particle collisions, but also benefited for establishing the continuous conductive pathways among the IFR particles. Accordingly, this work provided a promising and facile route to fabricate EMI shielding polymeric composites with excellent flame retardancy.

The engine oil pan is used for restraining pollutant and gathering greasing oil from the engine components’ surface which is significant for thermal dissipation and preventing deterioration of oil quality. The study intended to investigate and develop a hybrid sheet hydroforming process for fabricating an innovative high-capacity oil pan that has the characters of asymmetrical cavity depth and major lateral bulging. Firstly, a two-stage hydromechanical deep drawing (HMDD) process was accomplished, which included precedingly regional and eventually integral deep drawing assisted by fluid counter force. The finite element modeling (FEM) was employed to study the impact of the die fillet dimension as well as the loading routes on the formability of the preformed part. The limited drawing ratio can be enhanced from 2.34 to 2.77 for AISI 304 by HMDD. Hydro-bulging was subsequently investigated by the simulations accompanied by the relatively experimental verification. Both the simulated and experimental results showed that there is a remarkable influence of lubrication condition and intermediate heat treatment on the formability of the final part. The cracks occurred at the corners of the main bulging area can be alleviated by reduction of friction coefficient. Furthermore, wrinkles and cracks have been completely eliminated and the thinning ratio can be reduced to 31.8% for the final part, when intermediate heat treatment is additionally employed. It was concluded that the present hybrid sheet hydroforming process is feasible and sufficient to manufacture a sound engine oil pan without any defects through the optimization of the process parameters.

Graphical abstract, Al-Li alloys are attractive for military and aerospace applications because their properties are superior to those of conventional Al alloys. Their exceptional properties are attributed to the addition of Li into the Al matrix, and the technical reasons for adding Li to the Al matrix are presented. The developmental history and applications of Al-Li alloys over the last few years are reviewed. The main issue of Al-Li alloys is anisotropic behavior, and the main reasons for the anisotropic tensile properties and practical methods to reduce it are also introduced. Additionally, the strengthening mechanisms and deformation behavior of Al-Li alloys are surveyed with reference to the composition, processing, and microstructure interactions. Additionally, the methods for improving the formability, strength, and fracture toughness of Al-Li alloys are investigated. These practical methods have significantly reduced the anisotropic tensile properties and improved the formability, strength, and fracture toughness of Al-Li alloys. However, additional endeavours are required to further enhance the crystallographic texture, control the anisotropic behavior, and improve the formability and damage tolerance of Al-Li alloys.

High strain rate (HSR) forming has been found to be able to enhance the formability of sheet metals like electro-magnetic forming. Impact hydroforming (IHF) is proposed, in which the sheet is formed with high-pressure pulse combining hydroforming and HSR forming. An IHF bulge test setup was designed, 5A06 aluminium sheet was tested with strain rate of 2 × 103 s−1 showing remarkable thickness strain increase compared with quasi-static condition. A new IHF equipment is designed, the IHF process was verified effective with the equipment, complicated aluminium aircraft sheet part with high drawing ratio was formed that cannot be formed with quasi-static hydroforming.

Metal-semiconductor based Mott-Schottky (M-S) heterojunctions combining two or more functionalities in one unit can effectively improve their catalytic activity and durability due to the electronic coupling effects between distinct components. Although tremendous progress has been made in structure fabrication, controllable synthesis of one-dimensional (1D) M-S heterojunction and its application as electrocatalysts is still lacking. Herein, uniform and well-defined 1D Ni3S4-PtCo heteronanorods are synthesized via a facile solution method and employed as counter electrode (CE) catalyst in the dye-sensitized solar cells (DSSCs). By exploiting the benefits of both structural and compositional characteristics, namely, the direct electrical pathways of 1D nanostructure, optimized work function of metal alloy as well as the synergistic effect between Ni3S4 and PtCo, the as-designed Ni3S4-PtCo heteronanorods exhibit excellent catalytic activity and stability toward the reduction of triiodide in DSSCs. A DSSC with Ni3S4-PtCo achieves a high power conversion efficiency of 8.66% under AM1.5G illumination (100 mW cm−2), higher than that of pristine Pt-based device (8.12%). Moreover, the fast activity onset and relatively long stability further demonstrate that the Ni3S4-PtCo heteronanorod is a promising alternative to Pt in DSSCs. Considering the diversity of structures and components in heterostructures, the strategy presented here can be extended for synthesizing other well-defined 1D M-S heterojunctions, which may be used in the fields of catalysis, energy conversion and storage.

This study was carried out to investigate the effect of preliminary processes on tube hydroforming (THF) and to optimize the THF process parameters to achieve a sound complex 3D curved intercooler pipe without failure by numerical and experimental approaches. The effect of three-step rotary bending on the thickness distribution and microstructure of the tube has been evaluated. The necessity of heat treatment is analyzed prior to the THF process. The stroke of punches should be optimized separately according to the asymmetry geometry characteristics of the intercooler pipe. The suitable loading path is discussed during the THF process. The results obtained from simulation keep a reasonable agreement with that from the experiment.

Al-Li alloys have gained great attention for military, aerospace, and commercial applications because of their outstanding properties compared to commercial Al alloys. However, the tensile properties of former Al-Li alloys cannot fulfil most of the design and manufacturing characteristics because of their poor formability, and anisotropy in tensile properties. Therefore, the third generation of Al-Li alloys was developed to overcome the shortcoming of the former Al-Li alloys. The sensitivity of tensile properties and anisotropy behavior of Al-Li alloys to fibre orientation (sample orientation) and strain rate is vitally important from the aspects of formability improvements and developing material models for formability prediction. Therefore, this paper aims at investigating the influence of sample orientation and strain rates on the tensile properties and anisotropy behavior of Al-Li alloys sheet through quasi-static and dynamic uniaxial tensile tests. AA1420 and AA8090 sheets were selected from first and second generations of Al-Li alloys respectively because of their outstanding properties. Moreover, AA2060 is a new third generation Al-Li alloy launched at 2011 by Alcao Inc. The results showed that AA2060 alloy offers superior tensile properties compared with former Al-Li alloys, notably along the rolling direction and at high rates of deformation. For instance, the elongation to fracture of AA2060 was increased to 21.9 % at a strain rate of 2000 s-1. However, it’s formability at room temperature and quasi-static strain rate is very poor. Additionally, AA2060 is still suffering from anisotropic tensile properties, but the degree of anisotropy in less than the former Al-Li alloy. It is concluded that the quasi-static and dynamic tensile properties and formability for Al-Li alloy sheets show a dependable tendency in reference to sample orientation and don’t display the constant trend with the increasing of the strain rate.

Surfaces with patterned wettability contrast are important in industrial applications such as heat transfer, water collection, and particle separation. Traditional methods of fabricating such surfaces rely on microfabrication technologies, which are only applicable to certain substrates and are difficult to scale up and implement on curved surfaces. By taking advantage of a mechanical instability on a polyurethane elastomer film, we show that wettability patterns on both flat and curved surfaces can be generated spontaneously via a simple dip coating process. Variations in dipping time, sample prestress, and chemical treatment enable independent control of domain size (from about 100 to 500 μm), morphology, and wettability contrast, respectively. We characterize the wettability contrast using local surface energy measurements via the sessile droplet technique and tensiometry.

In order to form the thin-walled hollow parts with large deformation, a technology has been developed in the present study by combination of hydroforming with moving dies similar to forging process, known as a hydroforging technology. Based on the finite elements simulation, the process of hydroforging was investigated to avoid thinning, wrinkling, and bursting due to unreasonable selection of the internal pressure. The suitable loading path was discussed. The results from simulation keep a reasonable agreement with that from experiment.

In this study, a novel method was proposed to evaluate high strain rate (HSR) formability of Al-Cu-Mg 2B06-O sheets by impact hydroforming (IHF). IHF was suitable to manufacture hard-to-form sheets, since it combined the advantages of flexible liquid and impact impulse loading. Both 2D and 3D HSR formability curves were established to describe the relationship between impact energy, drawing height ratio (DHR) and deep drawing ratio (DDR). Moreover, the novel evaluation method was realized by finite element (FE) modeling using fluid-structure interaction (FSI) algorithm. FSI modeling was used to deal with the interaction of structure solid and flexible fluid. This evaluation means of FE modeling characterized with guiding production practice, saving evaluation costs, improving efficiency compared with corresponding experiments. The results obtained from FE modeling were in a remarkable agreement with those obtained from IHF experiments in the aspects of part shape, failure feature, thickness distribution. FE modeling showed that the limit deep drawing ratio (LDDR) and limit drawing height ratio (LDHR) were 1.99 and 1.04, respectively when the blank was completely deep drawn into the cavity of the die in one step only. FE modelling is proved to be reliable and efficient to estimate high strain rate formability of low formability metal sheets.

Fabricating electromagnetic interference (EMI) shielding materials with excellent flame retarding properties is significant to attenuate undesirable electromagnetic waves caused by electronic devices and simultaneously improve the flame safety of the electronic components. Herein, a novel EMI shielding composite with multilayered structure was fabricated at a low particle loading via layer-multiplying coextrusion technology. Especially, within the multilayered composites, poly (butylene succinate) (PBS) filled with carbon nanotubes (CNTs) was used to construct conducting layer while thermoplastic polyurethane (TPU) filled with intumescent flame retardants (IFRs) and CNTs was used to construct synergistic flame-retarding layer. The content of CNTs and IFRs in the whole system were below 4 wt% and 20 wt%, respectively. Morphological observation demonstrated the alternating multilayered structure and the selective distribution of IFRs and CNTs. Besides, by tailoring the layer numbers, the composites showed tunable EMI shielding and flame retarding performances. With regard to EMI shielding performance, the absorption-dominated average EMI shielding effectiveness (SE) values of both 8- and 16-layer specimens exceeded 30 dB in the range of 8.2–12.4 GHz. Furthermore, superior flame retardancy with prompt self-extinguishment and anti-dripping was achieved in these specimens owning to the production of continuous and foaming carbonaceous structure among layers. Especially the 8-layer specimen, the UL-94 rating was categorized in V-0. Consequently, this work provided a promising and facile route to fabricate polymeric composites simultaneously possessing excellent EMI shielding and flame-retarding properties to fulfill the stringent requirements in practical application.

In this paper, a facile approach to manipulating osteogenic activity of orthopedic implants by in situ electrically controlled wettability was developed. Glycosaminoglycans (GAGs), the major organic extracellular matrix (ECM) components, were electrochemically doped in nanostructured poly(3,4-ethylenedioxythiophene) (NPEDOT) on Ti-6Al-4 V orthopedic implants. The controlled wettability of NPEDOT/GAGs was achieved by in situ applying electrical stimulus. Moreover, the in situ electrically controlled wettability could be utilized to implement the manipulation of osteogenic activity of orthopedic implants. This facile strategy may open up a new avenue to electrically responsive biomedical applications.

Cells cultured in vitro using traditional substrates often change their behavior due to the lack of mechanical deformation they would naturally experience in vivo. To mimic the in vivo mechanical environment, we design temperature-responsive hydrogels with patterned surface creases as dynamic cell stretching devices. A one-step photolithographic method is first employed to pattern integrin-binding peptides on the gel, causing single cells or several-cell clusters to adhere to the surface in registry with creases. A variety of crease patterns are prescribed on a single substrate, enabling the mechanical deformation of cultured myoblast cells with different strain states and achieving tensile strain as high as 0.2. As creases provide large amplitude local deformation of the gel surface without the need for macroscopic deformation, can be formed on gels covering a wide range of modulus, and can be actuated using a variety of stimuli, they hold the potential to enable the design of high throughput and versatile platforms for mechano-biological studies.

Thin polymer films may undergo a wide variety of elastic instabilities that include global buckling modes, wrin- kling and creasing of surfaces, and snapping transitions. Tradi- tionally, these deformations have usually been avoided as they often represent a means of mechanical failure. However, a new trend has emerged in recent years in which buckling mechan- ics can be harnessed to endow materials with beneficial func- tions. For many such applications, it is desirable that such deformations happen reversibly and in response to well- defined signals or changes in their environment. While signifi- cant progress has been made on understanding and exploiting each type of deformation in its own right, here we focus on recent advances in the control and application of stimuli- responsive mechanical instabilities. V C 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 00, 000-000

Theory and experiment are presented to show that an interface between two soft materials under compression can form creases, a type of bifurcation distinct from wrinkles. While creases bifurcate from a state of flat interface by a deformation localized in space and large in amplitude, wrinkles bifurcate from a state of flat interface by a deformation nonlocal in space and infinitesimal in amplitude. The interfacial creases set in at a lower critical compression than interfacial wrinkles, but higher than surface creases. The condition for the onset of interfacial creases is scale-free, and is calculated in terms of elastic moduli, pre-strains and applied strains.

The development of novel materials with excellent performance depends not only on the constituents but also on their remarkable micro/nanostructures. In this work, manganese oxide (Mn

The potential benefits and mechanism of explosive explosion shockwave pretreatment on sludge dewatering treatments were investigated in this study. Water content of sludge cake after centrifugation was used to evaluate sludge dewaterability. Particle size, viscosity, turbidity, and micrograph were determined to explain the observed changes in the pretreatment process. The results indicated that the optimal pretreatment condition, generating the lowest water content of sludge cake, was 25 g explosive and 96.7% original sludge water content. This condition resulted in the reduced particle size and viscosity as well as increased turbidity. Particle size and viscosity significantly contributed to enhance sludge dewaterability. Micrograph investigation indicated that explosive explosion shockwave pretreatment could rupture sludge flocs, release physically bound water, and extracellular substances into the solution, consequently enhancing sludge dewaterability.

A nucleosides containing block copolymer, poly(polyethylene glycol methyl ether methacrylate)- block-poly(5'-O-methacryloyluridine) (PPEGMEMA 30- b-PMAU 80) was self-assembled in aqueous medium and cross-linked via RAFT polymerization at 60 degrees C to afford core-cross-linked micelles exhibiting a PPEGMEMA corona and a polynucleotide core. A disulfide cross-linking agent, bis(2-methacryloyloxyethyl)disulfide, was employed to cross-link the structure via the RAFT process resulting in core-shell nanoparticles, which can degrade under reductive conditions. The resulting core-cross-linked micelles readily hydrolyzed into free block copolymers in the presence of dithiothreitol (DTT) in less than 1 h, depending on the concentration of the reducing agent and the amount of cross-linker in the micelle. A small fraction of permanently cross-linked micelle was found as the result of conventional chain transfer to disulfide containing compounds. A model drug, vitamin B 2, was loaded into the micelle. The loading capacity increased with increasing cross-linking degree. The amount of drug released reached 60-70% after 7 h in the presence of DTT (0.65 mM), while the cross-linked micelle in the absence of dithiothreitol shows only a delayed drug release. Cytotoxicity tests confirmed the biocompatibility of the polymers and the residues after reduction.

ABA and BAB triblock thermoresponsive copolymers (A ¼N-isopropylacrylamide, B ¼2-hydroxyethyl methacrylate) have been synthesized by atom transfer radical polymerization (ATRP). BAB is shown to exhibit a higher transition temperature and a good solubility in water comparedtoABAwith thesamecomposition andconcentration.Thedifferences areattributed to the distinct micellar structure, which is regulated by the block order of the copolymers. It is speculated that ABA and BAB copolymers separately form branch and flower micelles in water, which mainly influence the course of phase transition. The moduli of the ABA copolymer solution are higher than those of the BAB above gel point. In terms of hypothesized micelle models, it is proposed that the ‘branch’ micelles of the ABA solution preferably form more physical interconnections.