Research on Anti-Fluctuation Control of Winding Tension System Based on Feedforward Compensation

In the fiber winding process,strong disturbance,uncertainty,strong coupling,and fiber friction complicate the winding constant tension control.In order to effectively reduce the influence of these problems on the tension output,this paper proposed a tension fluctuation rejection strategy based on feedforward compensation.In addition to the bias harmonic curve of the unknown state,the tension fluctuation also contains the influence of bounded noise.A tension fluctuation observer(TFO)is designed to cancel the uncertain periodic signal,in which the frequency generator is used to estimate the critical parameter information.Then,the fluctuation signal is reconstructed by a third-order auxiliary filter.The estimated signal feedforward compensates for the actual tension fluctuation.Furthermore,a time-varying parameters fractional-order PID controller(TPFOPID)is realized to attenuate the bounded noise in the fluctuation.Finally,TPFOPID is enhanced by TFO and applied to control a tension control system considering multi-source disturbances.The stability of the method is analyzed by using the Lyapunov theorem.Finally,numerical simulations verify that the proposed scheme improves the tracking ability and robustness of the system in response to tension fluctuations.

Engineering trienzyme cascade-triggered fluorescent immunosensor platform by sequentially integrating alkaline phosphatase, tyrosinase and horseradish peroxidase

Mulit-enzyme cascades are a major type of chemical transformations and play a crucial role in biological signal transduction and metabolism. Herein, a trienzyme cascade-triggered fluorescent immunosensor platform was constructed by sequentially integrating alkaline phosphatase(ALP), tyrosinase(TYR)and horseradish peroxidase(HRP). The proposed platform was based on HRP-induced a rapid in situ fluorogenic reaction between dopamine(DA) and 1,5-dihydroxynaphthalene(DHA) to produce a strong yellow azamonardine fluorescent compound(AFC). The obtained AFC was clearly characterized by highresolution mass spectrum,1H NMR,^(13)C NMR and theoretical calculations. The integration of the twoenzyme system(TYR and HRP) or three-enzyme system(ALP, TYR and HRP) led to a maximum of 400.0-fold and 250.0-fold fluorescence enhancements, respectively. Using cardiac troponin I(c Tn I) as the model antigen, a trienzyme cascade-triggered fluorescent immunosensor platform was developed for quantitative detecting c Tn I in a wide linear range from 2 ng/m L to 150 ng/m L with a detection limit of 0.67ng/m L. In addition, the proposed platform was successfully applied in detection of c Tn I in serum of clinical patients. Overall, the developed fluorescent immunosensor performs powerful implications for researching enzyme cascade systems in the field of biomedicine.

A topology optimization for finite 1D phononic structures with objective function involving tangential derivative quantities using TDBIE

The paper proposes a topology optimization method for 1D phononic structures to minimize the tangential component of particle velocity at the objective boundary.The tangential derivative of the boundary integral equation(TDBIE)is employed for the evaluation of the objective function involves the tangential derivative quantities.The topological derivative is derived through the adjoint method and the Neumann boundary condition of the adjoint field is obtained using the TDBIE.The average topological derivative which is obtained by calculating the average value of the topological derivative in each layer of design domains,is employed for the updating of the level set function.Numerical implementations demonstrate the proposed method is effective for the design of the 1D phononic crystals with the objective function involving tangential derivative quantities.

多孔介质中CO_(2)-CH_(4)水合物置换过程的强化方法研究进展

CO_(2)置换天然气水合物中的CH_(4)是一种非常有前途的天然气水合物开采方法,该法兼具能源安全开采和温室气体地层封存的双重优势。首先综述了多孔介质中CO_(2)-CH_(4)水合物置换的研究进展,分析了制约CO_(2)置换法开采天然气水合物商业应用的关键瓶颈问题,即置换过程存在的反应周期长、速率慢和效率低等问题。针对此问题,主要详述了强化CO_(2)-CH_(4)水合物置换的强化方法研究进展,包括注入不同的CO_(2)相态、小分子及混合气体的强化、结合传统开采法的联合强化以及其他强化方法的作用机理,讨论了各种强化方法尚待完善和改进的地方。最后提出了多孔介质中CO_(2)-CH_(4)水合物置换强化方法目前研究的不足和未来的研究方向。

Conductive Porous MXene for Bionic,Wearable,and Precise Gesture Motion Sensors

Reliable,wide range,and highly sensitive joint movement monitoring is essential for training activities,human behavior analysis,and human-machine interfaces.Yet,most current motion sensors work on the nano/microcracks induced by the tensile deformation on the convex surface of joints during joint movements,which cannot satisfy requirements of ultrawide detectable angle range,high angle sensitivity,conformability,and consistence under cyclic movements.In nature,scorpions sense small vibrations by allowing for compression strain conversion from external mechanical vibrations through crack-shaped slit sensilla.Here,we demonstrated that ultraconformal sensors based on controlled slit structures,inspired by the geometry of a scorpion’s slit sensilla,exhibit high sensitivity(0.45%deg^(-1)),ultralow angle detection threshold(~15°),fast response/relaxation times(115/72 ms),wide range(15°~120°),and durability(over 1000 cycles).Also,a user-friendly,hybrid sign language system has been developed to realize Chinese and American sign language recognition and feedback through video and speech broadcasts,making these conformal motion sensors promising candidates for joint movement monitoring in wearable electronics and robotics technology.

β-Cyclodextrin carbon-based nanoparticles with a core-shell-shell structure for efficient adsorption of crystal violet and bisphenol A

Textile wastewater contains highly toxic,nondegradable,carcinogenic organic pollutants,causing severe damage to the ecological environment.In this work,β-cyclodextrin carbon-sphere-based nanocomposite(CS/SiO_(2)@β-CD)with a core-shell-shell configuration was prepared by hydrothermal synthesis and subsequent sedimentation-azeotropic distillation with SiO_(2)as intermediate layer for the removal of crystal violet(CV)and bisphenol A(BPA).The chemical structure and morphology of the CS/SiO_(2)@β-CD were characterized by FT-IR,SEM and TEM.The effects of contact time,pH,temperature and initial concentration of the absorbates on the adsorption property were explored.The CS/SiO_(2)@β-CD showed excellent adsorption capacity on CV and BPA,and the maximum adsorption capacity was 87.873 mg g^(-1)and 165.095 mg g^(-1),respectively.Their adsorption process was in line with the pseudo-second-order and pseudo-first-order kinetic models,respectively.The adsorption thermodynamics could be better fitted by Langmuir model than by Freundlich model.The calculated thermodynamic parameters(-ΔG0,ΔS0 andΔH0)illustrated the adsorption of CV was endothermic,in contrast,the adsorption of BPA was exothermic process.Furthermore,the CS/SiO_(2)@β-CD showed excellent recovery performance,making it a potential adsorbent for the practical treatment of textile wastewater.

Three dimensional BC/rGA aerogel:preparation,characterization,and adsorption of Cr(Ⅵ)

Graphene-based composite aerogel doped with other low-cost materials can reduce the cost and promote the use in water treatment.This work prepared ball-milled biochar/reduced graphene oxide aerogel(BC/rGA)using GO and low-cost ball-milled biochar(BC)in a certain proportion with the freeze-thawing technique and sol-gel method,and applied BC/rGA on the Cr(Ⅵ)removal from aquatic environments.The characterization results showed that aerogel had a honeycomb briquette three-dimension(3D)and mesoporous structure with interconnected pores,and proved the preparation progress of aerogel in principle.Compared with GO,rGA and BC/rGA had better adsorption performance with 3D structure and well-developed pores,and BC/rGA with the mixture ratio of BC and GO of 1:4 was more appropriate.The adsorption kinetics data of rGA and BC/rGA_((1:4))were fitting well with the pseudo-second-order model(R^(2)>0.951),and the isotherm adsorption results were fitting the Langmuir model well(R^(2)>0.974).The results demonstrated that the adsorption process was monolayer and endothermic adsorption involving chemisorp-tion.Additionally,the adsorption capacities of rGA and BC/rGA_((1:4))at solution pH 2 were 3.71 and 3.89 times greater than those at solution pH 8,respectively.High background ion strength and low temperature slightly inhibited the adsorption of Cr(Ⅵ)by both rGA and BC/rGA_((1:4)).The adsorption mechanisms of Cr(Ⅵ)on rGA and BC/rGA_((1:4))were electrostatic interaction,reduction and ion exchange.The use of BC/rGA could reduce the cost and promote the green reuse of agricultural waste.Overall,BC/rGA could be used as a promising green adsorbent alternative for the feasible treatment of heavy metal contaminated water.