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Using a microelectromechanical system (MEMS) inertial measurement unit (IMU) array composed of multiple low-cost IMUs can reduce the measurement errors of inertial sensors, and improve its navigation performance. However, there is doubt about the benefit of the IMU array in the scene of GNSS/INS dynamic navigation . Therefore, to evaluate the navigation performance of the arrays, we developed four groups of IMU arrays, each containing 16 MEMS IMUs. Each IMU was accurately calibrated and compensated to improve the performance. The field experiments proved that the navigation accuracy of the IMU array improved by 3.4 times statistically over a single IMU, which is close to the theoretical limit, i.e., 4 times. Comparison data processing indicated that the individual IMU calibration reduced the horizontal position error of the array by 54% on average, which confirms that the precise calibration of each IMU, especially the cross-axis effect and mounting angles, is crucial to the array’s navigation performance. This research provides firm experimental support for the application of IMU arrays in the field of navigation.

Lignin, the most abundant aromatic polymer in nature, is one of the most promising renewable feedstocks for value-added polymer products. However, it is challenging to prepare high-performance and multifunctional polymer materials with renewable lignin because of its poor compatibility with the elastomer matrix. In fact, lignin often requires solvent fractionation, chemical modification, or prohibitively expensive additives. This work develops a cost-effective strategy to prepare ionomeric elastomer composites based on a commercial carboxyl elastomer and a high content of lignin without purification or chemical modification. The compatibility between the elastomer and lignin is improved by the incorporation of zinc oxide which creates metal-ligand coordination at the interfaces between the carboxyl groups of the elastomer and the oxygen-bearing groups of the lignin. This results in fine dispersion of the lignin in the elastomer matrix, even when its content reaches 50 wt %. The lignin/elastomer composites show excellent mechanical properties, which are attributed to the reinforcing effect of the lignin domains and the presence of abundant sacrificial coordination bonds. Moreover, ionic bonds and ionic aggregates created by the neutralization of the zinc ions with the carboxyl groups of the elastomer behave as physical crosslinks which endow the composites with excellent recyclability; namely, their mechanical properties are retained or even improved after multiple reprocessing cycles. They also show good self-repairability and shape memory. Hence, this work may open up new avenues to utilize lignin as a renewable alternative to petroleum derivatives for designing and fabricating high-performance and multifunctional elastomer materials.

Chiral metasurfaces have been proven to possess great potential in chiroptical applications. However, the multiband chiral metasurface with near-perfect circular dichroism has not been well studied. Also, the widely used bilayer metasurface usually suffers from the interlayer alignment and weak resonance. Here, we propose a twisted Moiré metasurface which can support three chiral bands with near-unity circular dichroism. The Moiré metasurface can remove the restriction of interlayer alignment, while maintaining a strong monolayer resonance. The two chiral bands in the forward direction can be described by two coupled-oscillator models. The third chiral band is achieved by tuning the interlayer chiral mode on resonance with the intralayer mode, to eliminate the parallel and converted components simultaneously. Finally, we study the robustness and tunability of the triple-layer Moiré metasurface in momentum space. This work provides a universal method to achieve three near-unity circular dichroism bands in one metasurface, which can promote applications of chiral metasurfaces in multiband optical communication, chiral drug separation, sensing, optical encryption, chiral laser, nonlinear and quantum optics, etc.

With excellent comprehensive properties, polylactic acid/poly(butylene adipate-co-butylene terephthalate) (PLA/PBAT) blends have found wide applications as degradable materials. During the processi...

Bound states in continuum (BICs) are believed to have the ability to achieve high quality factor (Q factor) resonances, which is very important for plasmonics. However, the study of plasmonic BICs is not sufficient. Herein, we design and fabricate a metal−insulator−metal (MIM) metasurface and demonstrate a one-dimensional plasmonic BIC experimentally. The even-order localized surface plasmon resonance (LSPR) modes have even parity at normal incidence. The symmetry-protected BIC can be achieved at Γ point. The band structure can be tuned by strong coupling between the localized plasmonic resonance and plasmonic lattice mode. Interestingly, two of the hybrid modes are also BICs. Although BICs cannot interact with the far field, we successfully demonstrate BIC splitting through far-field excitation. By further tuning the pitch of the MIM grating, the Friedrich–Wintgen BIC is also observed. Finally, we propose and preliminarily demonstrate an ultrathin bandpass spatial filter. These findings provide a new platform to study optical multipole BICs and can have applications in fields such as nano lasers, ultrasensitive sensors, filters, nonlinearity enhancement, and quantum optics.

This study aimed to modify an electrospun regenerated cellulose (RC) nanofiber membrane by surface grafting 2-(dimethylamino) ethyl methacrylate (DMAEMA) as a monomer via atom transfer radical polymerization (ATRP), as well as investigate the effects of ATRP conditions (i.e., initiation and polymerization) on enzyme immobilization. Various characterizations including XPS, FTIR spectra, and SEM images of nanofiber membranes before and after monomer grafting verified that poly (DMAEMA) chains/brushes were successfully grafted onto the RC nanofiber membrane. The effect of different ATRP conditions on laccase immobilization was investigated, and the results indicated that the optimal initiation and monomer grafting times were 1 and 2 h, respectively. The highest immobilization amount was obtained from the RC-Br-1h-poly (DMAEMA)-2h membrane (95.04 &plusmn, 4.35 mg), which increased by approximately 3.3 times compared to the initial RC membrane (28.57 &plusmn, 3.95 mg). All the results suggested that the optimization of initiation and polymerization conditions is a key factor that affects the enzyme immobilization amount, and the surface modification of the RC membrane by ATRP is a promising approach to develop an advanced enzyme carrier with a high enzyme loading capacity.

Phosphate fertilizers are used in horticultural production to increase yields, but overuse can result in inefficient crop uptake and large loss of phosphorus (P). Soil amendments could potentially reduce the risk of P loss while maintaining high crop yield. The objective of this study was to investigate the effect of organic and inorganic amendments on P fractions in soils with different P levels (low, medium and high), and the underlying mechanisms. Five treatments were included: no amendment (CK), chemical fertilizers (CF), rice straw (FS), chicken manure compost (CM), and vermicompost (VM). Counterintuitively, the proportion of organic phosphorus (OP) tended to increase in the CF treatment, especially in soil with low P level. Results indicated that the change in the proportion of OP was mainly controlled by soil acid phosphomonoesterase, alkaline phosphomonoesterase and phosphate-solubilizing microorganisms. The proportion of available P increased in soil with low P level, but decreased in soil with high P level in the VM treatment. Non-labile P was preferentially formed in the VM treatment because of the high calcium content in vermicompost. Phosphates associated with aluminum (Al-P) were significantly higher in the CM treatment than in other treatments. This treatment also had a large presence of Pseudomonas and Streptomyces bacteria, which are capable of promoting the formation of Al-P. Our results indicated that mechanisms causing changes in soil P fractions were distinctly different among various amendments, and that vermicompost had the greatest potential to increase P supply in soil with low P level, and to decrease the risk of P loss in soil with high P level.

Nanochannel plastic membranes are excellent materials for electroosmotic pump (EOP) elements owing to their surface charge properties, flexibility and cost-effectiveness. However, the surface charge properties of plastics are inferior to those of silicate-based materials. This paper reports a performance-enhanced EOP equipped with a glassified track-etch polycarbonate membrane (PC), which has a nanochannel surface covered by allylhydridopolycarbosilane (AHPCS). The effects of applied voltage, pH and membrane pore size on the electroosmotic flow velocity, along with a comparative study of the EOP with coated and pure membranes were investigated. It was found that when low DC voltage (10 - 40 V) was applied to both ends of the pump, the magnitude of the electroosmotic flow was linearly proportional to the voltage when the pore size of the membrane was less than 600 nm. A higher flow rate was obtained with larger pore size membranes. Compared with the uncoated film, the coated one showed faster electroosmosis velocity, with higher stability under the same conditions. For pH 10.0 buffer solution, a flow rate of 89.13 μL/min was obtained in the modified membrane-based EOP with excellent repeatability and durability, while the flow rate was only 37.89 μL/min in the bare PC membrane under 20 V. In order to demonstrate the performance of the developed EOP, the EOP was used for microcomplexometric titration to determine actual tap water hardness. The measured results were highly consistent with the results of a conventional complexometric titration methed. The EOP with an AHPCS-coated plastic membrane expanded the application range to harsh condition solutions, such as high-concentration acids or bases.

Ellipsoidal Fe3O4 @ C nanoparticles decorated fluffy structured graphene nanocomposites were synthesized. The effect of the magnetic nanoparticle content on the microwave absorption properties was studied. As electromagnetic wave absorber, we researched the electromagnetic absorption properties of the composites that were composed of the prepared nanocomposites and paraffin with a filler loading of 80 wt% paraffin. The results showed that the nanocomposites with suitable magnetic nanoparticle showed a maximum reflection loss of − 55.02 dB at 14.8 GHz with a coating thickness of 1.5 mm; and the bandwidth less than − 10 dB reached 5.44 GHz. The microwave absorption mechanism of the ellipsoidal Fe3O4 @ C nanoparticles decorated fluffy structured graphene nanocomposites mainly came from the effect of the fluffy structure, multiple reflections, interfacial polarization, magnetic loss and dielectric loss.

A visible-light-mediated radical tandem cyclization of ortho-isocyano-α-bromo cinnamates to 2-substituted indole-3-glyoxylates is achieved by formation of both C–C/C–S and C–O bonds. The reaction proceeds through a hitherto unprecedented bromine- or methoxy-group-promoted umpolung back electron transfer from an α-carbonyl radical to the photocatalyst. This method allows preparation of diverse 2-arylated or 2-thioarylated indole-3-glyoxylates. The glyoxylate group installed in the products can be utilized for several biologically relevant manipulations.

A giant SHG enhancement is achieved from monolayer-WS2 incorporated onto 2D plasmonic metasurfaces (Ag-nanogroove-grating) in resonance with the excitonic resonance of monolayer-WS 2 . An optical encoding technique is demonstrated based on plasmonic manipulation of SHG polarization.

We demonstrated a low-threshold lasing from a monolayer gain medium which is made possible due to 2D feedback mechanism via strong exciton-SPP coupling in both real space and a wide range of momentum space.

Liquid reclaimed rubber (LRR) was produced from ground tire rubber (GTR) in a continuous operation by using a co-rotating twin-screw extruder. The effects of reclaiming recipe, screw configuration combination, barrel temperature, and screw speed on the degree of reclamation were investigated. Through the adjustment of these conditions, an LRR with a sol fraction of 73.5% was obtained. Characterizations of the LRR by gel-permeation chromatography (GPC), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and re-vulcanized ability tests showed that the LRR had unique properties – low viscosity, good compatibility with natural rubber (NR), and re-vulcanized ability. Because of these properties of LRR, it was used as reactive polymeric plasticizer in NR to replace the conventional oils such as the environmental aromatic oil (EAO) used in this study. The plasticizing effect, acetone extraction, mechanical properties, and thermostability of the LRR/NR compounds were investigated and compared with those of EAO/NR compounds. The results show that the plasticizing efficiency of LRR is somehow lower than that of EAO. In addition, the LRR-plasticized NR has higher tensile strength, modulus at 100% and 300% elongation, hardness, extraction resistance, and thermostability than EAO-plasticized NR.

Four different reclaiming methods involving important reclaiming factors such as temperature, shear force, and atmosphere were used to reclaim ground tire rubber. The structure and performance of the reclaimed rubber were investigated. The reclaimed samples were all found to be mixtures of three parts: the sol part, a loosely crosslinked gel part, and low molecular substances. For a reclaimed product to have both good processability and mechanical properties, the ideal structure should be that the sol fraction and its molecular weight (Mn) are as high as possible. However, the high sol fraction and high Mn cannot be reached at the same time because of the nonselective scission of the main chain and crosslink bonds. Thus, for a reclaimed rubber to have high quality, the presence of some amount of gel fraction is essential. Our preliminary results showed that the recommended reclaiming method would be a process under oxygen-free atmosphere, without severe shear force, and at relative low temperature. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Sulfur-cured butyl rubber was devulcanized completely in supercritical CO2 by using diphenyl disulfide (DD) as a devulcanizing reagent. The optimum devulcanizing conditions were studied and the sol fraction of the reclaimed rubber obtained was up to 98.5%. The possible devulcanizing mechanism was investigated. Then, the sol component of reclaimed rubber was characterized by gel permeation chromatography, 1H-NMR, and differential scanning calorimetry, and the reclaimed rubber was characterized by TGA. Because of the substitution of a large portion of allylic hydrogen by sulfurated functional groups during vulcanization, the signal of the olefinic proton shift. As a result of the numerous decreases in the active crosslinking sites and the remaining DD, reclaimed rubber could not be cured by sulfur. At last, the blends of virgin butyl rubber and different contents of reclaimed rubber were revulcanized and their mechanical properties investigated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

To get the depth model of cratering stage of shaped charge jet penetrating into targets, the penetration process on the target is studied through numeral simulation and experiment. Parameters of cratering stage in penetration into different targets, which are formed from TNT and LX-14 charge with the respective calibers of 56mm and 82mm, are obtained by numerical simulation. The depth model of the cratering stage of shaped charge jet penetrating into targets is built by data fitting. Both of the COMP B charge simulation and experimental validation are conducted. The results show: the error between the calculated value and simulation value based on depth model is 4.6% and the error between theoretical value and experiment value is 4.8%, which indicates that the model can be used to calculate the depth of the cratering stage of jet penetrating into targets.

According to the property of circle contour, analysis the disappointment of circle contour extraction by traditional boundary tracing algorithm, especially under the condition of there is break in contour, an improved boundary tracing algorithm to extract the circle contour is proposed. Based on the break in circle contour, the confirmation method of boundary starting point and the end command of the algorithm are prescribed; According to the property of circle contour and inside branch, the new tracing principle is prescribed. The experiment shows that this method, which can extract the circle contour effectively and quickly, have a good ability of anti-disturbance to inside branch and false boundary.

To analyze the process of jet penetration in water medium quantitatively, the properties of jet penetration spaced target with water interlayer were studied through test and numerical simulation. Two theoretical models of jet penetration in water were proposed. The theoretical model 1 was established considering the impact of the shock wave, combined with the shock equation Rankine–Hugoniot and the virtual origin calculation method. The theoretical model 2 was obtained by fitting theoretical analysis and numerical simulation results. The effectiveness and universality of the two theoretical models were compared through the numerical simulation results. Both the models can reflect the relationship between the penetration velocity and the penetration distance in water well, and both the deviation and stability of theoretical model 1 are better than 2, the lower penetration velocity, and the larger deviation of the theoretical model 2. Therefore, the theoretical model 1 can reflect the properties of jet penetration in water effectively, and provide the reference of model simulation and theoretical research.

The projection algorithms for solving the constrained multiple-sets split feasibility problem are presented. The strong convergence results of the algorithms are given under some mild conditions. Especially, the minimum norm solution of the constrained multiple-sets split feasibility problem can be found.