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For lignocellulosic materials, water adsorption is extremely important for its product performance. For gaining a deeper understanding of moisture adsorption mechanisms, the molecular interactions between adsorbed water and a typical lignocellulosic material (i.e., wood) were studied using in-situ microscopic Fourier transform infrared (micro-FTIR) spectroscopy and a specially designed sample cell. The spectral shifts of 1733 cm(-1), 1604 cm(-1) and 1236 cm(-1) and different spectra between the moist and dry spectra indicated that carbonyl CO and CO groups preferred to combine with water molecules to form hydrogen bonds. From component band analysis of the spectral range of 2900-3700 cm(-1), three peaks at 3178 cm(-1), 3514 cm(-1) and 3602 cm(-1) were identified and assigned to strongly, moderately and weakly hydrogen-bonded water molecules, respectively. According to the variation trend of these hydrogen-bonded water molecules, three sections were divided for the adsorption process. Furthermore, the molecular structure of water absorbed by hydrophilic groups of wood in each section was demonstrated.

To overcome the poor mechanical strength of thermosensitive hydrogels, cellulose nanofibril (CNF) was used as a reinforcing agent for the preparation of PEG-based thermosensitive hydrogels through radical copolymerization. The maximum bloom and rupture strength of the hydrogel were increased respectively with 37.7% and 52% at CNF content of 0.35 wt%. The dynamic rheological properties further confirmed that CNF played a significant role in the improvement of mechanical strength, especially in elasticity. Due to abundant hydroxyl groups exposed on the surface of CNFs, the obtained hydrogels exhibited a decreasing equilibrium swelling ratio (ESR) and deswelling rate in comparison with untreated hydrogels. However, the water retention ratio (WRR) increased when CNF content increased. In addition, both treated and untreated thermosensitive hydrogels possessed continuous volume phase transition with temperature ranging from 0 to 70 °C. Combined with SEM and ATR-FTIR tests, it was indicated that CNFs contributed to the formation of hydrogen bonding between the copolymer matrix and a tight physical lock by means of an entanglement effect. These composite hydrogels are considered as promising candidates in various potential applications of soft actuators, biosensors, artificial muscles and drug delivery.

Cellulose nanofibrils (CNFs) are attracting much attention for the advantages of excellent mechanical strength, good optical transparency, and high surface area. An eco-friendly and energy-saving method was created in this work to produce highly negative charged CNFs using high-pressure mechanical defibrillation coupled with strong acid hydrolysis pretreatments. The morphological development, zeta potential, crystal structure, chemical composition and thermal degradation behavior of the resultant materials were evaluated by transmission electron microscopy (TEM), zeta potential analysis, X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and thermogravimetric analysis (TGA). These CNFs were fully separated, surface-charged, and highly entangled. They showed a large fiber aspect ratio compared to traditional cellulose nanocrystrals that are produced by strong acid hydrolysis. Compared to hydrochloric acid hydrolysis, the CNFs produced by sulfuric acid pretreatments were completely defibrillated and presented stable suspensions (or gels) even at low fiber content. On the other hand, CNFs pretreated by hydrochloric acid hydrolysis trended to aggregate because of the absence of surface charge. The crystallinity index (CI) of CNFs decreased because of mechanical defibrillation, and then increased dramatically with increased sulfuric acid concentration and reaction time. FTIR analysis showed that the C-O-SO3 group was introduced on the surfaces of CNFs during sulfuric acid hydrolysis. These sulfate groups accelerated the thermal degradation of CNFs, which occurred at lower temperature than wood pulp, indicating that the thermal stability of sulfuric acid hydrolyzed CNFs was decreased. The temperature of the maximum decomposition rate (Tmax) and the maximum weight-loss rates (MWLRmax) were much lower than for wood pulp because of the retardant effect of sulfuric acid during the combustion of CNFs. By contrast, the CNFs treated with hydrochloric acid had better thermal stability, because no functional groups were introduced on the surface.

A versatile and highly efficient method was developed to fabricate durable, superhydrophobic surfaces on various substrates, including wood, lignocellulosic fibers, cotton textiles, glass, and metals. This method employs various nanoparticles (i.e., SiO2 and TiO2) in combination with vinyltriethoxysilane (VTES) modification under gravity and pressure. The obtained superhydrophobic surfaces exhibited water contact angles greater than 150° and water sliding angles less than 4.5°. The superhydrophobicity of the coated surfaces was created by the random distribution of oligomer-wrapped nanoparticles having different sizes and shapes, and the oligomer originated from the hydrolyzed VTES. All superhydrophobic surfaces were able to sustain different types of abrasion, including finger wiping, brushing, and knife scratching. The mechanical durability of these superhydrophobic surfaces, with the exception of cloth and textiles, maintained the original superhydrophobicity even after intense sandpaper-induced abrasion. The excellent tolerance against vigorous abrasions was attributed to the hierarchical structure and strong interfacial adhesion of the coatings. Furthermore, all surfaces survived under the environmental conditions of 35 °C and 90% RH for 96 h. It was confirmed that these surfaces exhibited excellent self-cleaning and oil/water separation properties. The modification method developed in this work provides a facile, efficient route to fabricate large-scale, mechanically stable, and durable superhydrophobic surfaces for a wide range of potential applications.

This research aims to develop low cost, sustainable, environmentally friendly, and high performance water-based drilling fluids (WDFs) using bentonite (BT), polyanionic cellulose (PAC), and cellulose nanocrystals (CNCs). The effect of concentration of BT, PAC, and CNCs on the rheological and filtration properties of PAC/CNC/BT-WDFs was investigated. Eight empirical rheological models were applied to fit quantitatively the fluid properties. Results showed that the presence of PAC, CNCs, and BT improved the rheological and filtration properties of the WDFs. Among the eight empirical rheological models, the Sisko model performed the best in simulating the rheological behavior of the fluids. At the same concentration level of PAC and CNCs, CNCs had more impact on the rheological properties, whereas PAC had more influence on the filtration property. The incorporation of PAC resulted in very low permeable filter cakes, leading to the excellent filtration property. The combined use of PAC and CNCs yielded better...

Cellulose nanofibril (CNF) and epoxy nanocomposites with high visible light transmittance and low water sensitivity were manufactured by laminating thin layers of epoxy resin onto CNF films prepared through, pressurized filtration in combination with oven drying. Scanning Electron Microscopy (SEM) studies suggest that the resin component bonded to the CNF substrate well. Atomic Force Microscopy (AFM) observation reveals that the resin lamination led to smoother film surface, which helped enhance UV–vis transmittance. The addition of epoxy resin had little effect on the static and dynamic mechanical strength. However, crystalline and interconnected CNFs significantly reduced the loss factor and shifted the glass transition of composite to a high temperature. Compared to pure CNF films, the CNF/epoxy composites showed a 20% improved transparence in the visible light range. The CNF/epoxy composites demonstrated a sufficient water resistance. This composite film could be considered as a potential substrate material in the application of flexible electronics substrates.

A holocellulose framework (HCFW) with anisotropic microchannels, which is synthesized via a facile top–down strategy, is demonstrated to be an ideal anisotropic substrate to guide the directional assembly of CuS nanoparticles (CuS NPs) along the walls of microchannels. The oxygen-containing groups on the surface of HCFW and its abundant low tortuosity of channels contribute to the high loading (ca. 22.7 wt%) and homogeneous dispersion of CuS NPs as well as the fast outdiffusion of cytotoxic substances (such as Cu(I)/Cu(II)), hence endowing the composite with an outstanding antibacterial activity which achieves approximatively 100% of growth inhibition ratios for Escherichia coli and Staphylococcus aureus and extremely low minimal inhibitory concentrations of 8 μg mL−1 for these both bacteria. For drug delivery application, the release of doxorubicin hydrochloride (DOX) from CuS NPs@HCFW is well regulated by solution pH. A maximum cumulative release capacity of DOX (78.3%) is achieved at pH of 2.2. The cancer therapy capability of DOX-loaded CuS NPs@HCFW is also validated in vivo. Moreover, CuS NPs@HCFW has a strong antibiotic removal ability (~100% complete removal of ciprofloxacin within 120 min) by virtue of adsorption and catalytic oxidation in the presence of potassium peroxymonosulfate. These inspiring results not only indicate the high potential of CuS NPs@HCFW for antibacterial, pH-responsive drug delivery and antibiotic removal applications, but also provide a new sight for the development of novel anisotropic composites by using anisotropic HCFW for more extensive uses.

The fabrication of nanospheres with tailored structure has attracted much attention in material applications. Herein we found that the food additive, butylated hydroxytoluene (BHT), was able to adjust the solid and hollow structure of lignin nanospheres. At BHT concentrations greater than 0.3 mg/mL in tetrahydrofuran (THF), the obtained lignin nanospheres displayed a hollow structure due to phase separation between THF and water caused by BHT molecules, while the lignin nanospheres obtained without adding BHT exhibited a solid structure. BHT and lignin molecules containing a high content of the carboxy group did not participate in the formation of the nanospheres. Increases in the water stirring and dropping speeds reduced the diameter of the nanospheres, while increasing the initial concentration of lignin and BHT resulted in an increase in nanospheres diameters. Moreover, the shell wall thickness and single hole size could be controlled by employing the concentration of BHT and lignin. This work provides novel insights into the preparation of lignin nanospheres with tunable structures.

Developing electrodes with excellent electrochemical and mechanical properties is the key to achieve state-of-the-art flexible asymmetric supercapacitors (ASCs). This work proposes a facile and scalable strategy to prepare high-performance flexible electrodes based on carbon fiber-reinforced cellulose nanofiber/multiwalled carbon nanotube-hybrid aerogels (CF-CNF/MWCNT-HAs). The three-dimensional (3-D) porous structure, excellent conductivity, binder-free nature, and high strength of the CF-CNF/MWCNT-HAs enable it to serve as a powerful platform for constructing flexible electrodes with outstanding capacitive performance. The as-prepared CF-CNF/MWCNT/MnO2 positive electrode and CF-CNF/MWCNT/active carbon (AC) negative electrode display remarkably high areal-specific capacitances (1745 and 1273 mF/cm2 at a current density of 1 mA/cm2, respectively). In addition, the carbon fiber-reinforced electrode also presented an excellent mechanical property with a maximum stress up to 27.9 MPa. The as-fabricated CF-CNF/MWCNT/MnO2//CF-CNF/MWCNT/AC flexible ASC device exhibits significant capacitance and energy density of 19.4 F/cm3 and 8.93 mWh/cm3, respectively. Additionally, this flexible ASC device can retain more than 96.7% of its capacitance after 3000 charge-discharge cycles. These results will enable us to fabricate flexible solid-state ASC devices from CF-CNF/MWCNT-HAs, and to expand its applications in the fields of portable and wearable electronics.

Three kinds of hydrophobic groups grafted starches of maleic anhydride grafted starch (MAH-g-starch), lactic acid grafted starch (LA-g-starch), and methyl acrylate grafted starch (MA-g-starch) were prepared by in-situ solid phase polymerization. The results of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were confirmed successful grafting. The grafting ratios of MAH-g-starch, LA-g-starch and MA-g-starch were 6.50%, 12.45%, and 0.57%, respectively. Influenced by the grafting ratio, LA-g-starch had the best hydrophobic properties and the largest molecular weight, and those for MA-g-starch was the worst. The surfaces of grafted starches were covered with graft polymer, with obvious surface roughness and bond degree of MAH-g-starch and LA-g-starch. The crystalline structure of grafted starches showed some damage, with LA-g-starch exhibiting the greatest decrease in crystallinity, and less of a change for MA-g-starch. Overall, the grafting reaction improved thermoplasticity, with LA-g-starch the most improved, followed by MAH-g-starch, and then MA-g-starch.

We propose a single-photon three-dimensional compressive imaging system based on TCSPC. The system uses compressive sensing instead of raster scanning to achieve high spatial resolution, and only two-dimensional reconstructions are required to image a three-dimensional scene. We also propose a system simulation model based on Monte Carlo, which is conduct with double poisson stochastic process model. In the simulation model, we studied the effects of imaging time, optical noise ratio, and gating algorithm on the imaging performance of the system. The results show that the single-photon compressive 3D imaging system based on TCSPC can image in 5 seconds. Noise gating can effectively improve the 3D imaging quality of the system. Our simulation provides a good choice of parameters for subsequent experiments. It has played a theoretical guiding role in the research and application of the actual three-dimensional imaging system.

This research aims to provide a use for the large amount of abandoned, wasted straw and to provide high-quality building materials by producing a straw/magnesia lightweight composite (SMLC). The composite was composed of rice straw, foaming agent, and magnesium cement adhesive. The mechanical strength, toughness, heat insulation, and the flame-retardant performance of the material were tested to evaluate its performance as a potential construction material. The properties of straw and the bonding between straw and matrix were also studied. The results showed that the mechanical properties of the SMLC reached the maximum value when the straw was treated with 3% NaOH solution for 150 min. The siliceous protuberances, fatty acids, and aromatic compounds were effectively dissolved from the straw during this treatment. Compared with other composites in the construction industry, the SMLC is lighter, heat insulating, and nonflammable. These superb properties not only make the new composite an ideal construction material, especially as insulation partitions, but also provide a potential solution for the treatment of abandoned straw.

Rice grading is an important topic in the research of food security, which targets at assessing the quality of rice. However, there is seldom attention from researchers. In this paper, we propose a novel rice grading system, named as Deep-Rice, which is built upon a deep learning framework. Specifically, Deep-Rice employs a multi-view CNN architecture to extract the discriminative features from different views of rice images, and tries to optimize the CNN parameters by using a modified softmax loss function. In accompany with this deep model, we also build a large-scaled rice dataset, which is denoted as FIST-Rice, to provide a baseline database for the research of food security. FIST-Rice is the first publicly available multi-sensor rice dataset, which contains sound and unsound kernel samples with the total number of 30,000. Each sample is captured under three different illumination conditions. We evaluate the proposed Deep-Rice model on the FIST-Rice dataset by comparing with the AdaBoost and SVM methods. The experimental results indicate the Deep-Rice model achieves improved performance in different conditions of light intensity. The FIST-Rice dataset and baseline codes will be released for further public research.

Person re-identification is a useful technique to automatically match observations of the same person cross different times and different camera views. It attracts extensive attention and researches in computer vision community because of its application and challenge. An effect way to tackle the problem is to learn a useful distance metric from training examples. Then the learned metric could be used for distance calculations between a probe image and images from the gallery. For a real application, the labeled training samples usually increase gradually along the time. To keep the performance of a system for re-identification tasks, the learned model needs to be updated according to the newly added training sets. Although the learned model can be retrained with the whole dataset, the procedure is usually time-consuming. In this paper, we propose an incremental metric learning method based on the widely used XQDA metric for person re-identification. The key idea is that the covariance matrices of similar and dissimilar example pairs can be effectively updated incrementally in the XQDA metric learning algorithm. Then the final metric could be deduced in an incremental way. The proposed approach method is validated on two public available datasets, and the experimental results indicate the effectiveness of our proposed approach.

Bamboo plastic composites have become a hot research topic and a key focus of research. However, many strong, polar, hydrophilic hydroxyl groups in bamboo flour (BF) results in poor interfacial compatibility between BF and hydrophobic polymers. Maleic anhydride-esterified (MAH-e-BF) and lactic acid-esterified bamboo flour (LA-e-BF) were prepared while using an in situ solid-phase esterification method with BF as the raw material and maleic anhydride or lactic acid as the esterifying agent. Fourier transform infrared spectroscopy results confirmed that BF esterification with maleic anhydride and lactic acid was successful, with the esterification degrees of MAH-e-BF and LA-e-BF at 21.04 &plusmn, 0.23% and 14.28 &plusmn, 0.17%, respectively. Esterified BF was characterized by scanning electron microscopy, contact angle testing, X-ray diffractometry, and thermogravimetric analysis. The results demonstrated that esterified BF surfaces were covered with graft polymer and the surface roughness and bonding degree of MAH-e-BF clearly larger than those of LA-e-BF. The hydrophobicity of esterified BF was significantly higher than BF and the hydrophobicity of MAH-e-BF was better than LA-e-BF. The crystalline structure of esterified BF showed some damage, while MAH-e-BF exhibited a greater decrease in crystallinity than LA-e-BF. Overall, the esterification reaction improved BF thermoplasticity, with the thermoplasticity of MAH-e-BF appearing to be better than LA-e-BF.

Cellulose nanofibrils (CNFs), disintegrated from natural fibers, are promising alternatives in wastewater purification for the porous structure and numerous hydroxyls. The pristine CNFs aerogel has limited mechanical strength and are vulnerable to collapse when exposed to water. In this work, eco-friendly and recycled CNFs aerogel adsorbents were successfully prepared using cellulose nanofibrils (CNFs), which cross-linked by poly(vinyl alcohol) (PVA) and acrylic acid (AA). The combination of PVA and AA endowed CNFs aerogel strong three-dimensional porous structure and desirable adsorption properties. The heavy metal ions were adsorbed on the CNFs-PVA-AA (CPA) adsorbents efficiently and the maximum adsorption capacities for Cu2+ and Pb2+ approached 30.0 mg/g and 131.5 mg/g, respectively. The CPA adsorbent also showed excellent reusability and their adsorption capacities maintained 89% and 88% for Cu2+ and Pb2+ after 5 repeated uses. The adsorption of these heavy metal ions were confirmed to follow pseudo-second-order kinetic and Langmuir isotherm model. The functions of C ═ O and -OH were the major adsorption sites. Chemical adsorption combined with the porous physical adsorption made the CPA to be excellent adsorbent for the removal of heavy metal ions in wastewater.

Electrically conductive, yet stimuli-responsive hydrogels are highly desirable for many technological applications. However, the discontinuous conductivity of hydrogels during the response process has become a bottleneck that limits their application. To overcome this constraint, a linearly tunable, electrically conductive hydrogel is prepared using in-situ polymerized polyaniline (PANI) on a CNFs/MEO

Air-dried rosewood (Aniba rosaeodora) samples with sizes of 50 mm (length) by 50 mm (width) by 20 mm (thickness) were pretreated with NaOH to increase their permeability. The specimens were then impregnated with microcrystalline wax at a temperature of 100 °C to obtain various weight gains at four treatment durations. After impregnation, the swelling and shrinkage extents and surface hardness of the rosewood were measured. The results showed that, compared with untreated specimens, the linear swelling extent, volumetric swelling extent, and linear shrinkage extent of the impregnated specimens decreased by 75.23%, 59.85%, and 80.70%, respectively, and the surface hardness of the treated specimens increased by 43.36%. The impregnation with wax significantly increased the dimensional stability and surface hardness of the rosewood.

Novel wood-derived hierarchical porous carbons (HPCs) with biomimicry macro-/microporous and ordered mesostructures have been successfully prepared by using wood processing residues, such as poplar powder/or shavings, as a mimic-template to reproduce the wood cellular structures, resol as a precursor, and triblock copolymer F127 as a soft-template to construct the mesostructure onto the wood scaffold. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption results indicate that the obtained HPCs not only faithfully reproduce the wood cellular structures but also possess ordered mesostructures (p6 mm) with uniform pore sizes (∼4.0 nm) and high surface areas (∼463m2/g). Furthermore, the pore texture and properties of HPCs could be regulated by simply varying the dosages of resol precursor to poplar shavings. A formation process for wood-derived HPCs with controlled hierarchical nanostructures through wood-template and interface self-assembly approaches is propose...

Nowadays digital radio systems are replacing analog radio systems. In this paper, a CMOS RF receiver with frequency synthesizer and analog baseband is introduced, which was fabricated with a 0.18-µm CMOS process for DRM/DAB wideband applications. In the system, a fully differential low noise amplifier with a noise cancelling technology is adopted It has achieved a gain of 11.69 dB. A harmonic rejection mixer was implemented to realize the rejections of 3rd- and 5th-order harmonics. As the local oscillator, a wide-band frequency synthesizer provides a phase noise of ?125 dBc/Hz at 1-MHz offset. The designed RF receiver has achieved a conversion gain of 90 dB. The IIP3 of the receiver is in the range of ?25 to ?12 dBm, and the noise figure of 5.44---14.72 dB. The core circuits draw a current of 78.35 mA from a 1.8-V power supply and the chip occupies 6.46-mm2 die area.

The present study aims to investigate the structure–morphology–rheology relationships for cellulose nanoparticles (CNPs), including cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs). CNCs were extracted from never dried CNFs using sulfuric acid with controlled hydrolysis time. The crystalline structure, surface charge, morphology, and rheological behavior of the CNPs were measured and contrasted. The CNF suspensions exhibited rigid solid-like viscoelastic behavior even at a low concentration due to the formation of a highly entangled network. Upon acid hydrolysis, the network of rigid, long, and highly entangled nanofibers was eliminated, resulting in a significant loss of viscoelastic properties. Both steady-state and dynamic rheological measurements showed that the rheological behavior of the CNC suspensions was strongly dependent on the concentration and acid hydrolysis time. The CNC suspensions exhibited elastic gel-like rheological behavior at high concentrations but viscous liquid-like r...

Superhydrophobic nanocomposite surfaces were successfully fabricated on wood substrates via a one-step hydrothermal process. The morphology of the nanocomposite surfaces was characterized using scanning electron microscopy (SEM), and the elemental composition was determined via energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) analysis, and Fourier transform infrared (FTIR) spectroscopy. The results indicated that the crystallization of the anatase phase of TiO2 was prevented because of the presence of vinyltriethoxysilane [VTES, CH2CHSi(OC2H5)3] during the hydrothermal process. In addition, the nanocomposite contained Ti/Si particles with diameters ranging from 50 to 100 nm that thoroughly covered the wood substrate. Furthermore, the roughness coupled with the presence of low surface free energy groups led to superhydrophobicity; the static water contact angle (WCA) was as high as 153°, and the sliding angle was very low.

Cellulose nanofibril (CNF) films currently provide great opportunity in many applications with advantages of excellent mechanical strength, high light transmittance, and good barrier properties. However, processes for preparing CNFs are typically tedious and vary, along with their properties. Here, five preparation methods using various combinations of filtration, freeze-drying, and casting are applied to produce CNF films, and their major properties are compared. Three different types of CNFs having a range of fiber diameter and aspect ratio were examined using each of these five preparation methods. Because of limited hydrogen bonds and nanofibril arrangement, the freeze-dried CNF films displayed reduced mechanical strength and light transmittance compared to the other methods, although freeze-drying was relatively fast. Some effects of film production methods on measured crystallinity were also observed with freeze-dried samples having lower crystallinity than films similarly produced by filtration and drying. Free-standing CNF films produced by casting at room temperature required long times and mold growth was sometimes observed, but cast films made from 2,2,6,6-tetramethylpiperidine-1-oxyl radical-oxidized CNFs had the highest light transmittance of any samples. Filtration of CNF suspensions followed by air- or oven-drying produced films with minimal defects, high mechanical strength, and good light transmittance with relatively little effort. Therefore, this filtration procedure is recommended for producing CNF films.

Hygroscopic behavior is an inherent characteristic of nanocellulose which strongly affects its applications. In this study, the water vapor sorption behavior of four nanocellulose samples, such as cellulose nanocrystals and nanofibers with cellulose I and II structures (cellulose nanocrystals (CNC) I, CNC II, cellulose nanofibers (CNF) I, and CNF II) were studied by dynamic vapor sorption. The highly reproducible data including the running time, real-time sample mass, target relative humidity (RH), actual RH, and isotherm temperature were recorded during the sorption process. In analyzing these data, significant differences in the total running time, equilibrium moisture content, sorption hysteresis and sorption kinetics between these four nanocellulose samples were confirmed. It was important to note that CNC I, CNC II, CNF I, and CNF II had equilibrium moisture contents of 21.4, 28.6, 33.2, and 38.9%, respectively, at a RH of 95%. Then, the sorption kinetics behavior was accurately described by using the parallel exponential kinetics (PEK) model. Furthermore, the Kelvin-Voigt model was introduced to interpret the PEK behavior and calculate the modulus of these four nanocellulose samples.

An environment-friendly fluorescent nano-hybrid hydrogel has been synthesized successfully, from cellulose nanocrystal (CNC), acrylic acid (AA) and phosphorescent Eu2+/Dy3+ doped SrAl2O4 via free radical polymerization. The hydrogel network matrix fixed Eu2+/Dy3+ doped SrAl2O4 nanoparticles by polymer chains with coordinate bonds that prevented particles from aggregating and quenching in water. The fluorescent nano-hybrid hydrogel exhibited extremely high water absorption of which the swelling ratio in distilled water and NaCl salt solution were respectively of 323.35 g/g and 32.65 g/g. Furthermore, the hydrogel displayed excellent water retention property that can keep half of the moisture even exposed to 80 °C for 210 min. Besides, the hydrogel had bright green fluorescence under the sunlight or ultraviolet excitation, and the fluorescence intensity was up to 125477 after swelling 50 times in water. The time-resolved photoluminescence (TRPL) afterglow decay examination showed that the fluorescent emission persisted for 4 h after hydrogels excited at 368 nm wavelength UV-light for 10 min. The fluorescence intensity behaved significant linear relationship with the swelling ratio. As a result, these hydrogels were considered as promising candidates for the preparation of stable and sensitive sensor materials in green water detection.

Advanced flexible batteries with high energy density and long cycle life are an important research target. Herein, the first paradigm of a high-performance and stable flexible rechargeable quasi-solid-state Zn-MnO

Microwave pretreatment can increase the transverse permeability of wood. The effects of impregnation on microwave-pretreated wood with low-molecular weight phenol formaldehyde resin was investigated. The results showed that the improved transverse permeability of poplar wood that had received microwave pretreatment resulted in a positive influence on the effect of the impregnation. The maximum impregnation weight gain rate was 51.08%, with the average being approximately 40%. The average density of the specimens impregnated for 1.50 h at 0.8 MPa was 584.8 kg•m-3. During the course of the study, the resin present in the wood became distributed evenly in the vessel elements, wood fiber lumens, and intercellular spaces. Finally, the chromogenic reaction area accounted for 78.11% of the total area in the fluorescent staining diagram of the cross section.

Basalt fiber (BF) filled high density polyethylene (HDPE) and co-extruded wood plastic composites (WPCs) with BF/HDPE composite shell were successfully prepared and their mechanical, morphological and thermal properties characterized. The BFs had an average diameter of 7 μm with an organic surfactant surface coating, which was thermally decomposed at about 210 °C. Incorporating BFs into HDPE matrix substantially enhanced flexural, tensile and dynamic modulus without causing a noticeable decrease in the tensile and impact strength of the composites. Micromechanical modeling of tensile properties for the BF/HDPE composites showed a good fit of the selected models to the experimental data. Compared to neat HDPE, BF/HDPE composites had reduced linear coefficient of thermal expansion (LCTE) values. The use of the pure HDPE and BF/HDPE layers over a WPC core greatly improved impact strength of core–shell structured composites. However, the relatively less-stiff HDPE shell with large LCTE values decreased the overall composite modulus and thermal stability. Both flexural and thermal expansion properties were enhanced with BF reinforced HDPE shells, leading to well-balanced properties of core–shell structured material. Cone calorimetry analysis indicated that flammability performance of core–shell structured composites was improved as the BF content increased in the shell layer.

A wideband frequency synthesizer is designed and fabricated in a 0.18 μm CMOS technology. It is developed for DRM/DRM+/DAB systems and is based on a programmable integer-N phase-locked loop. Instead of using several synthesizers for different bands, only one synthesizer is used, which has three separated divider paths to provide quadrature 8-phase LO signals. A wideband VCO covers a frequency band from 2.0 to 2.9 GHz, generates LO signals from 32 to 72 MHz, and from 250 to 362 MHz. In cooperation with a programmable XTAL multi-divider at the PLL input and output dividers at the PLL output, the frequency step can be altered from 1 to 25 kHz. It provides an average output phase noise of ?80 dBc/Hz at 10 kHz offset, ?95 dBc/Hz at 100 kHz offset, and ?120 dBc/Hz at 1 MHz offset for all the supported channels. The output power of the LO signals is tunable from 0 dBm to +3 dBm, and the phase of quadrature signals can also be adjusted through a varactor in the output buffer. The power consumption of the frequency synthesizer is 45 mW from a 1.8 V supply.

A facile sol–gel method has been developed to create a superhydrophobic surface on aluminum substrate with tetraethylorthosilicate (TEOS) and vinyltriethoxysilane (VTES) as co-precursor at room temperature. Firstly, nanometer sized silica particles were self assembled on the substrate through the hydrolysis of TEOS. Then, the silica particles were modified with vinylsiloxane through the hydrolysis and condensation polymerization of VTES. The emphasis was focused on investigating the influence of the molar ratio between NH3·H2O and ethanol on the surface morphology and wetting property. The surface morphology was observed by scanning electron microscopy (SEM), the chemical composition and bonding state of the surface were explored by energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS), and the wetting property of the surface was investigated by water contact angle measurement (WCA). The modified silica-based surface possessed the greatest static contact angle of 154.9°, exhibiting excellent superhydrophobic property. A hierarchical microstructure with spherical microparticles of around 2 μm decorated with nanoparticles of around 450 nm was observed on the film surface. The surface was covered by hydrophobic vinyl groups via the decoration of silica microparticles with vinyl-terminated siloxane nanoparticles as evidenced by EDS, FTIR and XPS. The corrosion resistant performance and durability of the superhydrophobic silica-based surface formed on aluminum substrate in corrosive NaCl solution were estimated by electrochemical impedance spectroscopy (EIS) measurements. The appropriate equivalent circuit model was put forward to fit and analyze the EIS data. The electrochemical result revealed that the corrosion resistant performance of aluminum was improved greatly by the superhydrophobic treatment.

The effect of basic magnesium carbonate (BMC), magnesium hydroxide (MH), and magnesium chloride hydrate (MCH) on thermal degradation of red gum wood was studied using cone calorimetry, Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, and X-ray diffraction (XRD) characterization. The results showed common fire retardation actions of the three compounds by releasing incombustible gas and/or water vapor to dilute combustible gas in the flaming zone, and by converting to MgO, which had a satisfactory protective wall effect on the wood. Individually, BMC absorbed heat from the wood at the pre-decomposition stage and, thus, slowed down wood pyrolysis process. It slightly increased the char yield by charring in both the charring stage and the char calcination stage. MH lost water at about 270 °C, close to the temperature at which wood thermally degraded. MH rendered wood char quickly, and the compact char layer impeded further carbonization and burning of inner wood. MCH promoted charring with Mg2+ as a Lewis acid, and increased wood char yield. MCH also released Cl· free radical and HCl at 167 °C, which easily coordinated with combustion reaction radical, and slowed down, even inhibited, the combustion chain reaction.

A thermal shielding radiator, which has an extra cuboid cavity between channels and sealplate, is proposed to achieve a large temperature difference between the hot and cold surfaces and high temperature uniformity on the cold surface. To get uniform distribution of the flow inside each channel, the thermal shielding radiator with different inlet/outlet types (namely C-, Z-, Y- and I-type) are numerically simulated. It is found that I-type has the best performance in velocity uniformity. Due to the cavity, the temperature difference between two sides of the thermal shielding radiator improves significantly. Besides, the mini-channel with equidifferent fin thickness is also proposed, and more uniform flow and the temperature distribution on the cold surface are achieved. Moreover, effect of geometry, operating parameters on the flow and heat transfer performance for both the thermal shielding radiator and the heat radiator are studied and compared.

Various cellulose nanofibrils (CNFs) created by refining and microfluidization, in combination with enzymatic or 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized pretreatment were compared. The morphological properties, degree of polymerization, and crystallinity for the obtained nanofibrils, as well as physical and mechanical properties of the corresponding films were evaluated. Compared to refining, intense microfluidization contributed greater separation of nanofibril bundles, which led to an enhancement of mechanical strength and transparency for the resultant film. The selected enzymatic pre-treatments produced shortened fibers due to preferential hydrolysis of amorphous cellulose and, in combination with mechanical treatments, resulted in short and stiff cellulose nanocrystal (CNC)-like materials. Despite films from these CNC-like fibrils having inferior tensile strength, their tensile modulus and transparency were significantly improved compared to CNFs prepared without pre-treatment. The unique fiber morphology and high crystallinity potentially offer a green and ecologically friendly alternative for the preparation of CNCs and CNFs as part of an integrated biorefinery approach.

Flexible composite films were produced by impregnating aqueous phenol formaldehyde (PF) resin into water-swollen cellulose nanofibril (CNF) films. CNF films were prepared using a pressurized filtration method in combination with freeze drying. The freeze-dried films were swollen with water then impregnated with PF resin by soaking in aqueous resin solutions of varying concentrations. Small amounts of PF slightly enhanced the tensile properties of CNF films. The formulation with the best mechanical properties was CNF/PF films with 8 wt % resin exhibiting tensile stress and toughness of 248 MPa and 26 MJ/m3, respectively. Resin concentrations higher than about 8 % resulted in composites with decreased tensile properties as compared to neat CNF films. The wet strength of the composite films was significantly higher than that of the neat CNF films. The resulting composites showed greater resistance to moisture absorption accompanied by reduced thickness swelling when soaked in water as compared to neat CNF films. The composites also showed decreased oxygen permeability at low humidity compared to neat films, but the composites did not show improved barrier properties at high humidity.

To understand the swelling behavior of cellulose nanofibril (CNF) films, the dimensional variation of untreated and phenol formaldehyde modified CNF (CNF/PF) films soaked in distilled water was examined in situ with microscopic image recording combined with pixel calculation. Results showed that a dramatic thickness increase exhibited in both CNF and CNF/PF films, despite being at different swelling levels. Compared to thickness swelling, however, the width expansion for these films is negligible. Such significant difference in dimensional swelling for CNF and PF modified films is mainly caused by nanofibril deposition and their mesostructure. However, addition of PF modifier has a positive effect on the constraint of water absorption and thickness swelling, which is strongly dependent on PF loadings.

A CPW-fed ultra-wideband antenna was designed. The antenna was etched on a single-layer copper-cladding substrate, of which the material was FR4 with relative permittivity of 4.4, and the magnitude was 40.0 mm × 50.0 mm × 1.6 mm. The parameters of the antenna are simulated and optimized with HFSS. This paper proposes a new trapezoidal CPW-fed UWB antenna that the bandwidth (return loss ≤ ?10 dB) covers 2.7 - 9.3 GHz range, which means a relative bandwidth of 110% with good radiation patterns and gain. Simulated and measured results for return loss, radiation pattern and gain were presented. A good agreement has been obtained between the simulation and experiment and the proposed antenna meets the requirements of the ultra-wideband antenna.

The influence of nanocellulose on oil well cement (OWC) properties is not known in detail, despite recent advances in nanocellulose technology and its related composite materials. The effect of cellulose nanofibers (CNFs) on flow, hydration, morphology, and strength of OWC was investigated using a range of spectroscopic methods coupled with rheological modelling and strength analysis. The Vom-Berg model showed the best fitting result of the rheology data. The addition of CNFs increased the yield stress of OWC slurry and degree of hydration value of hydrated CNF-OWC composites. The flexural strength of hydrated OWC samples was increased by 20.7% at the CNF/OWC ratio of 0.04 wt%. Excessive addition of CNFs into OWC matrix had a detrimental effect on the mechanical properties of hydrated CNF-OWC composites. This phenomenon was attributed to the aggregation of CNFs as observed through coupled morphological and elemental analysis. This study demonstrates a sustainable reinforcing nano-material for use in cement-based formulations.

Green fir wood (Pseudotsuga menziesii) was modified with polyethylene glycol (PEG) to produce wood composites for energy storage and conversion. The PEG-modified wood composites were evaluated based on their dimensional stability, durability, and thermal properties by various analytical methods. The differential scanning calorimetry (DSC) results showed the melting temperature and the latent heat of the phase change material (PCM) composite were 26.74 °C and 73.59 J/g, respectively. Thermal cycling tests and thermogravimetric analysis confirmed the composite exhibited good thermal stability, reliability, and chemical stability. All treated specimens were free from noticeable defects, and the addition of a surface varnish coating prevented PEG from leaching. The PEG-modified composites exhibited improved dimensional and thermal performance, which makes this material a potential candidate for economical and green, lightweight building materials.

Co-polymer systems of methylene diphenyl diisocyanate (MDI) and phenol-formaldehyde (PF) resins with different molecular weights were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The FTIR and TGA coupled with differential thermogravimetric (DTG) results showed that higher molecular weight of PF resins not only promoted the reaction of isocyanate and PF co-polymer system, but also resulted in a better thermal property of prepared co-polymers. The XRD results revealed that higher molecular weight led to a higher proportion of ordered or crosslinking structures in the hybrid resin system. The relationship between the thermal resistance, mechanical properties and the molecular weights of phenolic resins needs further study. Validerad; 2016; Nivå 2; 20150827 (aliwan)

A series of vinyl-functionalized periodic mesoporous organosilicas (PMOs) were prepared by co-condensation of 1,4-bis (triethoxysilyl) benzene (BTEB) and triethoxyvinylsilane (TEVS) using the triblock copolymer Pluronic P123 as a template under acid conditions. It is found that the mesophases of resultant PMOs can be controlled via altering the fraction of organosilanes in the synthesis mixture and catalyst HCl concentration. With increasing fraction of TEVS, mesophase of the PMOs materials changed from p6mm to Ia3d, and then becomes a disordered material. For PMOs with 15 molar percentage of TEVS, the increase of HCl concentration can induce a transformation of mesophases from hexagonal p6mm to cubic Ia3d, whereas, a mixture of p6mm/disordered structure forms at lower acid concentration for the PMOs containing 5 % TEVS. The mechanisms of mesophase transformation were discussed based on the adsorption of TEVS into the micelles, influence of acid concentration on the hydrolysis and condensation rate, and the relative reactivities of the organosilane precursors.

As one of the most commonly planted species in China, Masson pine (Pinus massoniana) logs are potentially used for structural poles and piles. Because phytosanitary regulations require that logs be heat-treated before delivery to customers (log core temperature of 56°C for 30 min), interest has recently arisen in the determination of the time required to reach this criterion. In this study, 12 logs were heat-treated in a laboratory drying kiln with two types of schedules. Using partial differential energy and mass conservation equations with gradient boundary conditions, the temperature increase in a log during heating was simulated. The boundary value problem of heat and mass transfer was solved using a numerical method, namely, a control volume approach. Results from the comparison between the observed and calculated temperatures indicated that the heat transfer performance during log heating can be described with this heating model. This model might therefore serve as a guideline for estimating the log...

The vacuum–steam treatment of pallets and pallet parts for compliance with the International Standards for Phytosanitary Measures No. 15 regulation was evaluated. Vacuum–steam treatment consists of four steps: (1) vacuum, (2) heating, (3) holding at an increased temperature for a period of time, and (4) cooling. The system produces steam and maintains the saturation or superheated state in a flexible container. Hardwood dry and green pallets (122 by 101.6 cm) and notched stringers (122 cm long) were treated. After the vacuum was drawn, steam was injected into the container to heat the pallets through condensation. The steam was turned off when the center of the pallets or stringers reached 56°C. The stringer parts were treated in three stacking patterns: deadpacked piles of 12, 2, and 5 layers in a stack. Vacuum–steam treatment is significantly faster than conventional convective hot air treatment. The pallets were treated in less than 65 minutes, which included a vacuum time of 5 minutes and a h...

Wormhole-like mesoporous tungsten carbide/carbon (WC/C) composites can be prepared by an easy method that combines emulsion processing with triblock copolymer self-assembly strategy, followed by a high-temperature carbothermal reduction. X-ray diffraction, transmission electron microscopy, X-ray spectroscopy, thermogravimetric analysis and N 2 sorption techniques were employed to characterize the mesoporous WC/C composites. The results show that the resultant materials have a wormhole-like mesostructure containing nanoscale (∼40 nm) tungsten carbide particles, and high surface areas (up to 314.9 cm 2 /g). It is proposed that a general assemble procedures are responsible for the wormhole-like mesoporous WC/C composites.

The purpose of this study was to investigate the vibrational properties and corresponding anisotropicity in wood during different states of moisture sorption. Samples of maple (Acer spp.) and red oak (Quercus rubra Michx.f.) were moisture conditioned by the adsorption process from an ovendried state and by the desorption process from a water-saturated state. The dynamic modulus of elasticity (DMOE) and logarithmic decrement (δ) were examined as a function of grain orientation during moisture change processes and under constant moisture contents (MC). It was observed that regardless of species and grain direction, the DMOE and δ were lower and higher, respectively, during the moisture change process compared with those measured without a change in MC. The increase in δ value during adsorption was greater than that during desorption. These results suggest that wood in an unstable state shows lower elasticity and strength and higher damping properties than wood in an equilibrium state. Furthermore, ...

Grafting of methyl methacrylate (MMA) onto bamboo cellulose using ceric ammonium nitrate (CAN) as an initiator was carried out under microwave irradiation. The graft copolymers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The effects of varying the microwave power, exposure time and concentration of initiator of graft polymerization were studied by determining the grafting parameters, such as grafting percentage and grafting efficiency. The experimental results showed that the optimal conditions for grafting were: [CAN] = 0.004 mol/L, which was acidified with 0.1 mol/L nitric acid; exposure time, 9 min; and the microwave power, 160 W. Moreover, the moisture absorption ability of the graft copolymers decreased significantly with the increase in grafting percentage.

In this work, we applied a fast and simple method to synthesize cellulose nanocrystal (CNC) aerogels, via a hydrothermal strategy followed by freeze drying. The characteristics and morphology of the obtained CNC-g-AA aerogels were affected by the hydrothermal treatment time, volume of added AA (acrylic acid), and the mass fraction of the CNCs. The formation mechanism of the aerogels involved free radical graft copolymerization of AA and CNCs with the cross-linker N,N&prime, methylene bis(acrylamide) (MBA) during the hydrothermal process. The swelling ratio of the CNC-g-AA aerogels was as high as 495:1, which is considerably greater than that of other polysaccharide-g-AA aerogels systems. Moreover, the CNC-g-AA aerogels exhibited an excellent methyl blue (MB) adsorption capacity and the ability to undergo rapid desorption/regeneration. The maximum adsorption capacity of the CNC-g-AA aerogels for MB was greater than 400 mg/g. Excellent regeneration performance further indicates the promise of our CNC-g-AA aerogels as an adsorbent for applications in environmental remediation.