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Wang Z.,Donghua University | Liu B.,Donghua University | He J.,Donghua University | He J.,Key Laboratory of Textile Science & Technology
Journal of Industrial Textiles | Year: 2015

Bismuth vanadate-coated cotton fabric was synthesized by a chemical bath deposition method at low temperature (≤100℃) and characterized by using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and UV-V is diffuse reflectance spectroscopy. Its photocatalytic activities were evaluated by decomposition of C.I. reactive blue 19 in aqueous solution under visible light irradiation. The as-prepared composite possesses excellent photocatalytic activity for the degradation of liquid contamination especially in static system due to its large specific surface area. The reduction of total organic carbon (about 48.0% after 4 h of irradiation) showed that the mineralization of C.I. Reactive Blue 19 over the bismuth vanadate-coated cotton fabric is realizable. Moreover, the preparation of the composites is convenient for potential practical application. The formation mechanism of bismuth vanadate on the fabric was also discussed preliminarily. © The Author(s) 2013.

Qu J.,Donghua University | Chen R.,Donghua University | Dong X.,Key Laboratory of Textile Science & Technology | He J.,Donghua University | He J.,Key Laboratory of Textile Science & Technology
Textile Research Journal | Year: 2014

The color fastness of reactive cotton dyeings under simultaneous exposure to light and saline water, as well as light and perspiration, is one of the most important characteristics especially for summer-time sportswear. In order to illustrate the dual effects (i.e. favorable or adverse) of saline water on the photofading of reactive azo-dyes, the degradation mechanism and reaction kinetics of dye photodecoloration in the presence of various NaCl concentrations were investigated in simulated experiments. Experimental results indicated that the photodecoloration of dye solution was mainly attributed to the hydroxyl radical. Due to the quenching of the hydroxyl radical by the chloride ion, the dye photodecoloration rate decreased with low NaCl concentration (<10 g/L). Nevertheless, higher NaCl concentration (>50 g/L) was beneficial to produce reactive chlorine species, resulting in a significant increase of the photodecoloration rate. Moreover, reaction kinetic analysis demonstrated that the observed first-order rate constant for the photodecoloration of dye solution consistently increased with the increasing NaCl concentration. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Jiang R.,Key Laboratory of Textile Science & Technology | Jiang R.,Donghua University | Hu J.,Key Laboratory of Textile Science & Technology | Yang X.,Key Laboratory of Textile Science & Technology | Ding X.,Key Laboratory of Textile Science & Technology
Fibers and Polymers | Year: 2016

Tactile textures of textiles depend on the non-linear friction vibrations which are generated by the fingertip sliding across textile surfaces. It is relatively difficult to understand these complex vibrations, since skin and textile are viscoelastic and their vibration spectra are too redundant. Currently, the method of handling such complex vibrations in the field of tactile evaluation and tactile rendering usually adopts Fourier analysis. Unfortunately, only Fourier analysis can neither trace the multi-scales surface textures nor delete the redundant information. This paper proposed a time-frequency analysis, which extends the recorded 1-D vibration signals to 2-D time-frequency spaces to realize the multi-scales decomposition and dimension reduction. By applying this method to four typical kinds of texture surfaces, such as grille and textiles, the results demonstrated that the time-frequency analysis can accurately capture the major textural features from friction-induced vibration signals and decrease the dimensionality of complex signals. Considering the merits of dimension reduction, the time-frequency analysis could use in the texture synthetic of tactile virtual rendering and the tactile design of textile products. © 2016, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Zhou J.,Donghua University | Wang J.,Donghua University | Wang J.,Key Laboratory of Textile Science & Technology
Journal of the Textile Institute | Year: 2015

Developing an efficient real-time detection algorithm is quite important for an automated inspection system. This paper presents a practical method based on local singular value decomposition (SVD) and normalised cross-correlation (NCC) for real-time defect detection in woven fabrics. As fabric-textured images exhibit high periodicity among the repeated sub-patterns, non-defective or normal image samples (image patches) can be efficiently approximated as a linear combination of the basis vectors (BVs) obtained via SVD. Since these BVs are recovered from normal samples, they will only capture the key structural features of the non-defective images. When using the BVs to model new samples, we can expect defective or abnormal samples with structural features not found in normal cases will incur substantial approximation errors. Therefore, complex defect detection can be converted to a template matching problem, where the robust NCC is utilised to measure disparities between the original and its approximation for defect identification. Experimental results on various real-world fabrics exhibit accurate defect detection with low false alarm rate, and we also conduct a comparison with a feature extraction-based method to further confirm the effectiveness of our algorithm. © 2014 The Textile Institute.

Zhang S.,Key Laboratory of Textile Science Technology | Li F.A.-X.,Donghua University | Yu J.-Y.,Donghua University
Cellulose Chemistry and Technology | Year: 2011

The coagulation properties of cellulose-NaOH/thiourea/urea/H 2O solutions under various coagulation conditions have been investigated, to determine the kinetics of this special coagulation process (known as including diffusion on the contact surfaces of the polymer solution with the precipitant and the chemical reaction between acid and alkali). The observation was made that, at the beginning of the coagulation process, thickness of the coagulated layer, ξ(t), is proportional to the square root of time, √ t, which agrees with Fick's law. By building a coagulation model, the influence of precipitant composition and concentration, of coagulation time, bath temperature and cellulose concentration on the coagulation rate has been demonstrated. The process of cellulose shaping from NaOH/thiourea/urea/H 2O solutions can be characterized by examining the thickness and surface morphology of the coagulated layer, which is a reliable and direct method for understanding and controlling the cellulose regeneration behavior. It was found out that the coagulation rate enhanced with the increase in coagulation temperature, and decreased with increasing cellulose concentration. The activation energy of coagulation was calculated to be of 10.808 KJ/mol. The kinetics of diffusion-controlled chemical reactions has been viewed as the mechanism of coagulation.

Zhou D.,Donghua University | Zhu Z.,Donghua University | Zhu Z.,Key Laboratory of Textile Science & Technology | Liu B.,Donghua University | Liu B.,Key Laboratory of Textile Science & Technology
Materials Letters | Year: 2016

A novel reduced graphene oxide (RGO)/BiVO4/SiO2 composites with high-efficiency visible-light photocatalytic activity were synthesized by a simple one-step solvothermal method at 180 °C for 4 h. The as-prepared RGO/BiVO4/SiO2 hybrid material was characterized by X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectrum (UV–vis DRS), respectively. The photocatalytic activity of samples was evaluated by the degradation behaviors of C.I. Reactive Blue 19 in aqueous solution under visible light irradiation at room temperature, which is much higher than that of the pure semiconductor materials BiVO4 and hybrid material BiVO4/SiO2. © 2016 Elsevier B.V.

Wang C.-E.,Donghua University | Wang C.-E.,Key Laboratory of Textile Science & Technology | Zhang P.-H.,Donghua University | Zhang P.-H.,Key Laboratory of Textile Science & Technology
Autex Research Journal | Year: 2016

Biodegradable intravascular stent has attracted more and more focus in recent years as an effective solution for angiostenosis. Ideal stents were expected to exhibit sufficient radial force to support the vascular wall, while suitable flexibility for the angioplasty. After vascular remodeling, stents should be degraded into small molecular and be eliminated from human body, causing no potential risk. In this paper, poly-p-dioxanone (PDO) monofilament was braided into net structure with four different braiding density, two of which exhibited sufficient radial force larger than 30 kPa, and three of which showed the bending rigidity within 11.7-88.1 N•mm2. The degradation behaviors of monofilaments and stents have been observed for 16 weeks. The findings obtained indicate that degradation first occurred in morphology region, which induced temporary increase of crystallinity, monofilament bending rigidity and stent mechanical properties. During this period, monofilament tends to be hard and brittle and lost its tensile properties. Then the crystalline region was degraded and stent mechanical properties decreased. All the results reveal that the PDO intravascular stents with braided structure were able to afford at least 10 weeks of sufficient support to the vascular wall. © AUTEX.

Wang C.-E.,Donghua University | Wang C.-E.,Key Laboratory of Textile Science &Technology | Zhang P.-H.,Donghua University | Zhang P.-H.,Key Laboratory of Textile Science &Technology | And 2 more authors.
Textile Research Journal | Year: 2016

Biodegradable intravascular stents could become totally degraded after supporting the stenosis diseased vascular without risks of thrombus and restenosis. As the earliest used biodegradable material on stents, poly-l-lactic acid (PLLA) has favorable mechanical and degradable performance. In this paper, poly-lactic acid was used as a stent material for the imitation of the S7 stent (Medtronic AVE, Minnesota, USA). The Z-structure stent was designed and constructed with textile methods by wounding and bonding the strut with a cylindrical mold. Poly-lactic acid Z-structure stents were made into different forms with two different bonding methods for the comparison of stent mechanical properties. In the meantime, polydiaxanon monofilament was used for the preparation of the Z-structure stent and WallStent to compare with poly-lactic acid stents. The stent radial force was tested by the platform compression method. Experimental results showed that the polydiaxanon Z-structure stent had a higher radial force than the poly-lactic acid ones because of better mechanical properties of the strut. Small-diameter stents expressed higher radial force, whereas stents with more crown rows had lower radial forces. Stents bonded with medical glue had higher radial force but lower fastness and inefficient self-expanded performance. The WallStent and Z-structure stent both had favorable elastic resilience performance, whereas the Z-structure stent performed better in compression resistance under large deformation © 2016, © The Author(s) 2016.

Lv T.-J.,Donghua University | Lv T.-J.,Key Laboratory of Textile Science & Technology | Long H.-R.,Donghua University | Long H.-R.,Key Laboratory of Textile Science & Technology
Textile Research Journal | Year: 2015

In this paper, based on Hessian invariant moments, a new approach for classification of fancy weft knitted stitch was proposed. The speeded up robust features (SURF) algorithm was used to identify fancy weft knitted samples including cable stitch and tuck stitch. Weft knitted stitch images generally contain many repeated features, wrong matches are easily encountered when the SURF algorithm is applied to match images. To resolve this problem, the inflection point of misjudgment was found out. The general regularity of faults and the key threshold were concluded by analyzing a number of classification experiments. The results show that wrong matches can be removed by locking the inflection point and feature matching of fancy weft knitted stitch is proved to be feasible for assigning an unknown image to one of a set of known texture classes. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav

Han W.,Jiaxing University | Wang X.,Donghua University | Wang X.,Key Laboratory of Textile Science & Technology
Fibers and Polymers | Year: 2016

The characteristics of molten polymer plays a major role in fiber formation in the melt blowing (MB) process. In this paper, the Maxwell model and two kinds of the standard linear solid (SLS) models in the bead-viscoelastic element model are proposed for melt blown fiber formation simulation. The fiber diameter, velocity and stress are studied with these different constitutive equations of polymer. The trajectory path of fiber whipping is obtained using numerical simulation and compares with the actual fiber motion which is captured with a high-speed camera. The results present that the Standard Linear Solid Model (SLS) is better than Maxwell model to predict the melt blown fiber’s characteristics under the same air drawing conditions, including fiber diameter, velocity and stress. The whipping motion of the fiber also can be well expressed by SLS constitutive model. The mathematical model with SLS model provides a clear understanding on the mechanism of the formation of microfibers during melt blowing. © 2016, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

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