Effects of Orientations and Regions on Performance of Online Soluble Solids Content Prediction Models Based on Near-Infrared Spectroscopy for Peaches

Predicting the soluble solid content (SSC) of peaches based on visible/near infrared spectroscopy has attracted widespread attention. Due to the anisotropic structure of peach fruit, spectra collected from different orientations and regions of peach fruit will bring variations in the performance of SSC prediction models. In this study, the effects of spectra collection orientations and regions on online SSC prediction models for peaches were investigated. Full transmittance spectra were collected in two orientations: stem-calyx axis vertical (Orientation1) and stem-calyx axis horizontal (Orientation2). A partial least squares (PLS) method was used to evaluate the spectra collected in the two orientations. Then, each peach fruit was divided into three parts. PLS was used to evaluate the corresponding spectra of combinations of these three parts. Finally, effective wavelengths were selected using the successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS). Both orientations were ideal for spectra acquisition. Regions without peach pit were ideal for modeling, and the effective wavelengths selected by the SPA led to better performance. The correlation coefficient and root mean square error of validation of the optimal models were 0.90 and 0.65%, respectively, indicating that the optimal model has potential for online prediction of peach SSC

Nanowire-Based Polypyrrole Hierarchical Structures Synthesized by a Two-Step Electrochemical Method

National Nature Science Foundation of China [30500727, 30870617, 30870648]A simple two-step electrochemical method is proposed for the synthesis of nanowire-based polypyrrole hierarchical structures. In the first step, microstructured polypyrrole films are prepared by electropolymerization. Then, polypyrrole nanowires are electrodeposited on the surface of the as-synthesized microstructured polypyrrole films. As a result, hierarchical structures of polypyrrole nanowires on polypyrrole microstructures are obtained. The surface wettabilities of the resulting nanowire-based polypyrrole hierarchical structures are examined. It is expected that this two-step method can be developed into a versatile route to produce nanowire-based polypyrrole hierarchical structures with different morphologies and surface properties

Perpendicularly aligned carbon nanotube/olefin composite films for the preparation of graphene nanomaterials

There remains a common and critical challenge in the preparation of carbon nanotube (CNT) composite materials, i.e., random dispersion of CNTs in the second phase. Here we have reported a general method to prepare perpendicularly aligned CNT/olefin composite films through a conventional slicing technique. The thickness of a composite film can be accurately controlled from about fifty nanometers to fifty micrometers, and the diameter and density of CNTs may be varied in a wide range as required. In particular, due to the generated defect at the end during the slicing process, the separated CNTs from the composite film have been easily unzipped to produce graphenes in the forms of nanoribbons and nanosheets with a yield of almost 100% under ultrasonic treatment

Electrochemical synthesis of polypyrrole nanowires in the presence of gelatin

National Nature Science Foundation of China [30870617, 30870648, 30500127]Biotemplating is an emerging, unique approach for the synthesis and organization of the organic or inorganic materials into well-defined nanostructures. In this article, conducting polymer polypyrrole (PPy) nanowires were electrochemically synthesized using a protein molecule, gelatin, as a template. The morphologies, microstructures, chemical compositions, and electrochemical performances of the obtained nanowires were investigated in detail. It was found that the gelatin played an important role in the formation of the PPy nanowires and the morphologies of the nanowires were closely related to the electrodes used. This work not only extended the application of gelatin to the synthesis of the conducting polymer nanowires, but also presented a simple and useful route to the fabrication of PPy nanowires with different length, from normal size to superlong size. (C) 2010 Elsevier B.V. All rights reserved

Functionalized anodic aluminum oxide (AAO) membranes for affinity protein separation

National Nature Science Foundation of China [30500127]; Natural Science Foundation of Fujian Province [C0510005]An ideal affinity membrane should own well uniformities. However, most existing microporous membranes used as affinity matrices generally have wide pore size distribution and some thickness variation. In this paper, chitosan (CS)-anodic aluminum oxide (AAO) composite membrane with excellent uniformities, such as narrow pore size and porosity distribution, as well as uniform membrane thickness, was fabricated. for the first time. Cu(2+)-attached affinity membrane was obtained by immobilizing Cu(2+) on the CS-AAO membrane. The contents of CS and Cu(2+) of affinity membranes were similar to 49.7 and 27.15 mg/g membrane. respectively. The Cu(2+)-attached affinity membranes were used to recover a model protein, hemoglobin, from hemoglobin-phosphate solution (batch manner) and from the hemolysate (dynamic manner). The protein adsorption indicated that the adsorption capacity of hemoglobin was similar to 17.5 mg/g membrane, and the adsorption isotherm fitted the Freundlich model well. Elution of protein showed desorption ratio was up to 91.2% using 0.5 M imidazole aqueous solution as the desorption agent. The adsorption capacities of all the tested affinity membranes did not significantly change during the repeated adsorption-desorption operations. The result of dynamic experiment showed Cu(2+)-attached affinity membranes can well purify the hemoglobin from the red cell lysate. (C) 2008 Elsevier B.V. All rights reserved

Facile Fabrication of PEDOT:PSS‐Based Free‐Standing Conducting Film for Highly Efficient Electromagnetic Interference Shielding

Abstract With the growing popularity of portable and wearable smart electronics, the electromagnetic shielding materials with high shielding effectiveness (SE) as well as light weight and excellent mechanical strength are in high. In this work, the PEDOT:PSS‐based free‐standing conducting film with superior conductivity and mechanical strength is prepared through a facile fabrication. The cellulose nanofibers (CNFs) are first introduced to induce an orderly grow and stack of the PEDOT grains. A phosphoric acid immersion process is then employed to remove the insulating CNF and PSS in the film. The obtained free‐standing conducting film shows a record conductivity of 3508 S cm−1 and its elongation at break reaches 3.75%. Encouragingly, the film delivers an excellent electromagnetic interference (EMI) shielding behavior with a SE of 49 dB in the X‐band (8.2–12.4 GHz) at a thickness of 4 µm. The superior conductivity, mechanical strength, and high SE as well as its facile solution processability make this free‐standing conducting film to be an attractive EMI material for portable and wearable smart electronics

A polypyrrole-based microchip for controlled drug release

National Nature Science Foundation of China [30500127, 30870617, 30870648]; Open Foundation of Pen-Tung Sah Micro-Electro-Mechanical Systems Research Center of Xiamen UniversityA novel polypyrrole-based microchip has been developed by electrochemical deposition of drug-doped Polypyrrole films on the Au microelectrode arrays. The drug release from the microchip is controlled by a potential application. Due to its unique configuration, the microchip exhibits some appealing characteristics, such as being able to supply single or multiple drugs with precise small doses, ability to achieve pulsatile release mode, small in size, and good biocompatibility, and thus has the potential for application as implantable device in the field of controlled drug release. (C) 2009 Elsevier Ltd. All rights reserved