Layer by Layer Self-assembly Fiber-based Flexible Electrochemical Transistor

Poly(3,4-ethylenedioxyethiophene)-polystyrene sulfonic acid(PEDOT:PSS)/polyallyl dimethyl ammonium chloride modified reduced graphene oxide(PDDA-rGO)was layer by layer self-assembled on the cotton fiber.The surface morphology and electric property was investigated.The results confirmed the dense membrane of PEDOT:PSS and the lamellar structure of PDDA-rGO on the fibers.It has excellent electrical conductivity and mechanical properties.The fiber based electrochemical transistor(FECTs)prepared by the composite conductive fiber has a maximum output current of 8.7 mA,a transconductance peak of 10 mS,an on time of 1.37 s,an off time of 1.6 s and excellent switching stability.Most importantly,the devices by layer by layer self-assembly technology opens a path for the true integration of organic electronics with traditional textile technologies and materials,laying the foundation for their later widespread application.

"Three-in-One" Multi-Scale Structural Design of Carbon Fiber-Based Composites for Personal Electromagnetic Protection and Thermal Management

Wearable devices with efficient thermal management and electromagnetic interference(EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers(CF) @ polyaniline(PANI)/silver nanowires(Ag NWs) composites with a “branch-trunk” interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional(1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of Ag NWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI(branch) was firmly attached to the CF(trunk) through polydopamine(PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.

Analysis of piezoelectric semiconductor fibers under gradient temperature changes

Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.

A Combined Discrete Event—Agent Based Approach to Modeling Tensile Strength of One-Dimensional Fibrous Materials. Face Validation and Effect of the Basic Model Parameters

A combined method of discrete event and agent based modelling has been applied to the computer modelling and simulation of the tensile strength of one-dimensional fibrous materials (ODFM). This combined method is based on the concept of discrete event simulation as being applied to the modeling of the structure of the fiber flow and on the concept of agent based modelling for modelling and simulation of the fiber interaction within the structure of the fibrous material. Frictional and traction forces arise as the result of this fiber interaction. A model of the ODFM tensile strength, which is based on the slippage effect, is created and studied in this research. Only frictional and traction forces determine the tensile strength in this kind of the model. The article examines the validation problem of the slippage effect based tensile strength model and questions regarding the strength potential estimation through variation in the parameters of the model.

Hemostatic Effect of Chitosan-based Fiber

[Objective] The aim was to investigate the hemostatic effects of chitosan-based fibre on liver. [Method] The liver hemorrhage model of rabbit was established. Hemostasis was performed with chitosam-based fiber in experimental group, surgicel in control group and no material in blank group. The hemostatic effects were evaluated by total blood loss (TBL) and hemostatic rate. [Result] Experimental group had no bleeding in observation period, with the hemostatic rate of 100% and the blood loss of only (0.443±0.30) g/kg, better than the control group and blank group (P<0.005). [Conclusion] Chitosan-based fiber has effective hemostasis in liver wound, which will provide reliable information for the clinical trials.

A Temperature-Insensitive Amplified Spontaneous Emission Broadband Source Based on Er-Doped Fiber

To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.

Smart Behavior of Carbon Fiber Reinforced Cement-based Composite

The electrical characteristics of cement-based material can be remarkably improved by the addition of short carbon fibers. Carbon fiber reinforced cement composite (CFRC) is an intrinsically smart material that can sense not only the stress and strain, but also the temperature. In this paper, variations of electrical resistivity with external applied load, and relation of thermoelectric force and temperature were investigated. Test results indicated that the electrical signal is related to the increase in the material volume resistivity during crack generation or propagation and the decrease in the resistivity during crack closure. Moreover, it was found that the fiber addition increased the linearity and reversibility of the Seebeck effect in the cement-based materials. The change of electrical characteristics reflects large amount of information of inner damage and temperature differential of composite, which can be used for stress-strain or thermal self-monitoring by embedding it in the concrete structures.

Piezoresistivity in Carbon Fiber Reinforced Cement Based Composites

The results of some interesting investigation on the piezoresistivity of carbon fiber reinforced cement based composites (CFRC) are presented with the prospect of developing a new nondestructive testing method to assess the integrity of the composite. The addition of short carbon fibers to cement-based mortar or concrete improves the structural performance and at the same time significantly decreases the bulk electrical resistivity. This makes CFRC responsive to the smart behavior by measuring the resistance change with uniaxial pressure. The piezoresistivity of CFRC under different stress was studied, at the same time the damage occurring inner specimens was detected by acoustic emission as well. Test results show that there exists a marking pressure dependence of the conductivity in CFRC, in which the so-called negative pressure coefficient of resistive (NPCR) and positive pressure coefficient of resistive (PPCR) are observed under low and high pressure. Under constant pressures, time-dependent resistivity is an outstanding characteristic for the composites, which is defined as resistance creep. The breakdown and rebuild-up process of conductive network under pressure may be responsible for the pressure dependence of resistivity.

Effects of the Component and Fiber Gradient Distributions on the Strength of Cement-based Composite Materials

The effects of the component gradient distribution at interface and the fiber gradient distribution on the strength of cement-based materials were studied. The results show that the flexural strength and compressive strength of the mortar and concrete with interface component and fiber gradient distributions are obviously improved. The strengthes of the fiber gradient distributed mortar and concrete (FGDM/C) are higher than those of fiber homogeneously distributed mortar and concrete (FHDM/C). To obtain the same strength, therefore, a smaller fiber volume content in FGDM/C is needed than that in FHDM/C. The results also show that the component gradient distribution of the concrete can be obtained by means of multi-layer vibrating formation.

QTL Mapping for Fiber Quality Traits Based on a Dense Genetic Linkage Map with SSR,TRAP,SRAP and AFLP Markers in Cultivated Tetraploid Cotton

Cotton is one of the most important economic crops in the world,and it provides natural fiber for the textile industry.With the advancement of the textile technology and increased consumption demands on cotton fiber,both cotton yield and quality should be enhanced.However,cotton yield

Influence of Water Content on Conductivity and Piezoresistivity of Cement-based Material with both Carbon Fiber and Carbon Black

The influence of water content on the conductivity and piezoresistivity of cement-based material with carbon fiber （CF） and carbon black （CB） was investigated. The piezoresistivity of cement-based material with both CF and CB was compared with that of cement-based material with CF only, and the changes in electrical resistivity of cement-based material with both CF and CB under static and loading conditions in different drying and soaking time were studied. It is found that the piezoresistivity of cement-based material with both CF and CB has better repeatability and linearity than that of cement-based material with CF only. The conductivity and the sensitivity of piezoresistive cement-based material with both CF and CB are enhanced as the water content in piezoresistive cement-based material increases.

Effects of precoating and calcination on microstructure of 3D silica fiber reinforced silicon nitride based composites

Three-dimensional silica fiber reinforced silicon nitride based composites were fabricated by preceramic polymer infiltration and pyrolysis method using perhydropolysilazane as a precursor. The effects of precoating and high temperature calcination on the microstructures of the composites were investigated by scanning electron microscopy. For the composite without a precoating, the fracture surface is plain, and the fiber/matrix interfaces become very unclear after calcination at 1 600 ℃ due to intense interfacial reactions. The composite with a precoating shows tough fracture surface with distinct fiber pull-outs, and the fiber/matrix interfaces are still clear after calcination at 1 600 ℃. It is the appropriate precoating process that contributes to the good interfacial microstructures for the composite.

Piezoresistivity of Carbon Fiber Graphite Cement-based Composites with CCCW

The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were studied.The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena.The percolation threshold was about 20%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,20wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain sensing.The measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22,respectively.With the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.

A Novel Mach–Zehnder Interferometer Based on Hybrid Liquid Crystal–Photonic Crystal Fiber

We propose a novel all fiber Mach-Zehnder interferometer（MZI） based on photonic crystal fiber（PCF） filled with liquid crystal（LC）. The interference between the core mode and the cladding modes of a PCF is utilized.To excite the cladding modes, a region is formed using fiber fusion splicer. Due to the fact that varying effective index difference between the core region and the LC-filled cladding region can cause different transmission spectra,we mainly study the MZIs with different LC-filled structures and different lengths of LC filling. The measured results demonstrate that quite clear interference spectra can be obtained. Through analysis spatial frequency spectrum and temperature spectrum of two MZIs with different LC-filled structures, we can obtain that the MZI with adjacent two LC-filled holes has clearer interference spectrum and higher temperature sensitivity. Thus we choose this MZI to measure the temperature sensitivity with different lengths of LC filling. When the length of LC filling is 2 cm, the temperature sensitivities can be enlarged to 1.59 nm/C. The interferometer shows a good temperature tunability and sensitivity, which can be a good candidate for a highly tunable optical filtering and temperature sensing applications.

Determination of Some Physical and Mechanical Properties of the Wood-Based Panels Modified by Acrylic Textile Fiber

In this research, a series of wood-based panels were produced by using wood chips [beech (Fagus Sylvatica L.) and Scotch pine (Pinus sylvestris L.)] as wastes of wood-working workshops and acrylic fibers as wastes of textiles factory. Four kinds of different panels (Eltapan I, II, III and IV) were obtained by mixing these components in different composition (0%, 25% and 50%). Some physical and mechanical properties of the samples taken from these panels were determined in accordance with ASTM D1037-12 and ASTM-C 1113. The values were compared to properties of industrially produced chipboard. As a result, the textile fibers used as additive material reduced density, thermal conductivity and bending resistance of wood panel and increased dimensional stability of wood panel.

Dual-Wavelength Passively Q-Switched Ytterbium-Doped Fiber Laser Based on Aluminum Oxide Nanoparticle Saturable Absorbers

We report on generation of a dual-wavelength, all-fiber, passively Q-switched ytterbium-doped fiber laser using aluminum oxide nanoparticle （Al2O3-NP） thin film. A thin film of Al2O3 was prepared by embedding Al2O3-NPs into a polyvinyl alcohol （PVA） as a host polymer, and then inserted between two fiber ferrules to act as a saturable absorber （SA）. By incorporating the Al2O3-PVA SA into the laser cavity, a stable dual-wavelength pulse output centered at 1050 and 1060.7nm is observed at threshold pump power of 80mW. As the pump power is gradually increased from 80 to 300mW, the repetition rate of the generated pulse increases from 16.23 to 59 kHz, while the pulse width decreases from 19 to 6μs. To the best of our knowledge, this is the first demonstration for this type of SA operating in the 1 μm region.

Magneto and Electro-Optic Intensity Modulator Based on Liquid Crystal and Magnetic Fluid Filled Photonic Crystal Fiber

We propose a novel light intensity modulator based on magnetic fluid and liquid crystal（LC） filled photonic crystal fibers（PCFs）. The influences of electric and magnetic fields on the transmission intensity are theoretically and experimentally analyzed and investigated. Both the electric and magnetic fields can manipulate the molecular arrangement of LC to array a certain angle without changing the refractive index of the LC. Therefore, light loss in the PCF varies with the electric and magnetic fields whereas the peak wavelengths remain constant. The experimental results show that the transmission intensity decreases with the increase of the electric and magnetic fields. The cut-off electric field is 0.899 V/um at 20 Hz and the cut-off magnetic field is 195 m T. This simple and compacted optical modulator will have a great prospect in sensing applications.

THE CONVERSION OF PAN-BASED STABILIZED FIBER TO CARBON FIBER

When the PAN-based stabilized fiber(PAN-SF) was converted to the carbon fiber, the effect of some of the carbonizing parameters on the structure and properties of the resulting carbon fibers, such as the molecular structure development, element contents, morphology and mechanical properties, was discussed. The results show that the carbonizing temperature, the purity of the inert gas and the de-oil pretreatment of the tiber have a great influence on them.

Deformation Resistance Effect of PAN-based Carbon Fibers

The deformation resistance effect of polyacrylonitrile （PAN）-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge factor （fractional change in resistance per unit strain） of PAN-based carbon fibers is 1.38, which is lower than that of the commonly-used resistance strain gauge. These may due to that the electrical resistivity of carbon fibers decreases under tensile stress. In addition when the carbon fibers are stretched, the change of its resistance is caused by fiber physical dimension and the change of electric resistivity, and mainly caused by the change of physical dimension. The mechanical properties of carbon fiber monofilament were also measured.

Efficiency of employing fiber-based finite-length plastic hinges in simulating the cyclic and seismic behavior of steel hollow columns compared with other common modelling approaches

The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three diff erent modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fi ber-based fi nite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fi ber-based distributed plasticity and concentrated plasticity models are utilized. The effi ciency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.