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Consumptive thirst such as dry mouth and polydipsia, frequent urination polyuria, fear of heat and hyperhidrosis and loss of other body fluids, yin deficiency and internal heat expression, and irritability and other abnormal emotional symptoms are common. The Synopsis of Golden Chamber need to be further explored for the treatment of miscellaneous diseases. The dialectical thought has a high clinical application value. Lily disease treatment recommendations in the Synopsis of Golden Chamber are explored. The symptoms of lily disease are varied and uncertain, which are caused by the scattering and wandering aimlessly of heat pathogen. The pathogenesis of lily disease can be examined through external symptoms such as bitter taste in mouth, red urine, and faint and rapid pulse. Diabetes is also closely related to yin deficiency and internal heat, and the pathogenesis of the two is similar. Mental symptoms are common characteristics of lily disease and diabetes. The method taken from the Synopsis of Golden Chamber and Baihe-like prescriptions for the treatment of diabetes are effective. By identifying different patterns, symptoms, and indicators, we can select lily bulb, common anemarrhena, rhizome, figwort root, unprocessed rehmannia root, and other drugs to treat diabetes, in order to improve our understanding of lily disease and provide new ideas for diabetes treatment. [ABSTRACT FROM AUTHOR]

Manganese‐based phosphate cathodes are promising candidates for developing advanced sodium‐ion batteries, primarily driven by their reliable elemental abundance, low toxicity, and desirable cycling performance. However, the cooperative Jahn–Teller effect of Mn3+ will inevitably lead to structural disorder and irreversible phase transition, thus greatly harming the reversible capacity, rate, and cycling performance. Herein, a stable NASICON‐type Na3MnHf(PO4)3 cathode is demonstrated with a volume variation of 1.9% upon the process of Na+ extraction/insertion based on the robust Hf─O bond and symmetrical MnO6 octahedron. Moreover, making full use of the stepwise redox reactions of Mn2+/Mn3+/Mn4+, this cathode reveals excellent cycling stability with a capacity retention of 85.4% after 2500 cycles at 10 C. Matching with commercial hard carbon anodes, the assembled full cell keeps a capacity retention of 92.1% with the Coulombic efficiency close to 100% after 600 cycles at 1 C. The research promises opportunities for the structural amelioration of manganese‐based phosphate cathodes toward the application in high‐performance sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Solid‐state metal batteries have displayed great advantages in the domain of electrochemical energy storage owing to their remarkably improved energy density and safety. However, the practical application of solid‐state batteries (SSBs) is still greatly impeded by unfavorable interface stability and terrible low temperature performance. In this work, a local targeting anchor strategy is developed to realize an impressively long cycling life for a NASICON‐based solid‐state sodium metal battery at 0 °C. With the electrochemical migration of K+ from the cathode side to the anode side, a spontaneous generated liquid Na–K interphase can stabilize the ceramic electrolyte/metallic Na anode interface, and address the issues of sluggish kinetics at the interface together with metal dendrite deposition. In addition, the capability of K+ conduction in NASICON is also theoretically and experimentally validated. Of particular note, a K2MnFe(CN)6 cathode paired with a Na3Zr2Si2PO12 ceramic electrolyte and metallic Na anode, enable the long‐term cycling and excellent rate capability of all‐solid‐state sodium batteries at 0 °C. Without the purposely designed matrix host for a liquid Na–K interphase, this work opens up a new route for the design of high energy density SSBs. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) is usually processed and used in a form of aqueous dispersion. A large number of inter- and intramolecular hydrogen bonds make it very difficult to obtain suitable rheological behavior for processing. In this study, carbon particles with different topological shapes were added into PVA aqueous dispersion to tune the steady and dynamic rheological behavior. The results show that the zero-dimensional particles (carbon black, CB) increase monotonically the zero-shear viscosity of PVA dispersion, while the one-dimensional particles (carbon nanotubes, CNTs) make it first increase, and then decrease and rise again, like an N-shape, and the two-dimensional particles (graphene oxide, GO) can make it first decrease and then increase, exhibiting a U-shape. It is believed that the topological shape of the carbon particles brought about these discrepancies. The zero-dimensional particles mainly act as physical crosslinking points due to their small size. While at a certain content, both CNTs and GO can destroy the intermolecular hydrogen bonds between PVA chains because the PVA chains can twine around the slim CNTs and the large planar size of GO prevents the adsorbed PVA from forming hydrogen bond with other chains. The high hydroxyl value of carbon particle surface could strengthen this effect. It is expected that the viscosity of polymer dispersion can be regulated by particles with different topological shape and the surface characteristic, so as to widen the operable concentration range during preparing composite functional materials. [ABSTRACT FROM AUTHOR]

• The paper reports three isostructural Ag/Cu alloyed [Ag 3 Cu 8 ] clusters protected by alkyne and phosphane ligands. • Their crystal structures are determined by X-ray single crystal diffraction and their compositions are further determined by ESI-MS. Furthermore, their structures are descripted in details. • The photoluminescence of these clusters in the solid and CH 2 Cl 2 solution are explored. • These clusters exhibit AIEE performance in n-hexane–CH 2 Cl 2 mixed solvents with a 20-fold increase of quantum yields. • Intermolecular forces are analyzed by crystal structure analysis and Hirshfeld surface analysis. In this work, three isostructural clusters of [Ag 3 Cu 8 (R-Ph-C C) 6 (N-triphos) 2 (Ph 2 PO 2) 3 ](NO 3) 2 (R = 4-H (1), 4-CH 3 (2), 4-F (3)) were successfully synthesized and structurally determined by single crystal X-ray diffraction. At room temperature, they show weak photoluminescence in CH 2 Cl 2 solution at ∼715 nm but with a 20-fold increase of quantum yields in their aggregation. Crystallographic and Hirshfeld surface analysis reveals a plentiful of intermolecular interactions (C−H...N, C−H...O, C−H...π, π...π) exist in their solid states, which can inhibit the intra-/inter-molecular motions (vibration and rotation) and thus generate the aggregation induced emission enhancement phenomenon. Moreover, their solid luminescent intensities at 100 K are much higher than those at room temperature. Comparisons of their luminescence show that the substituents on the para-positions of phenylethynes not only have a charge effect on emission, but also have steric effect on the molecular stacking and supramolecular interactions in the aggregated and crystalline states, and then on the aggregation-induced emission. The density functional theory (DFT) calculations show that the possible luminescence mechanism of these clusters is ligand-to-metal−metal charge transfer (LMMCT). [Display omitted] [ABSTRACT FROM AUTHOR]

This article uses deep neural network technology and combines digital HRM knowledge to research human-job matching systematically. Through intelligent digital means such as 5G communication, cloud computing, big data, neural network, and user portrait, this article proposes the design of the corresponding digital transformation strategy of HRM. This article further puts forward the guaranteed measures in enhancing HRM thinking and establishing HRM culture to ensure the smooth implementation of the digital transformation strategy of the HRM. This system uses charts for data visualization and flask framework for background construction, and the data is stored through CSV files, My SQL, and configuration files. The system is based on a deep learning algorithm for job applicant matching, intelligent recommendation of jobs for job seekers, and more real help for job applicants to apply for jobs. The job intelligent recommendation algorithm partly adopts bidirectional long and short-term memory neural network (Bi-LSTM) and the word-level human post-matching neural network APJFNN built by the attention mechanism. By embedding the text representation of job demand information into the representation vector of public space, a joint embedded convolutional neural network (JE-CNN) for post matching analysis is designed and implemented. The quantitative analysis method analyzes the degree of matching with the job. [ABSTRACT FROM AUTHOR]

In this study, vapor-grown carbon nanofiber (VGCNF)-filled and shape-memory epoxy (EP)-fixed melamine sponge (VGCNF@EP-MS) was fabricated for adjustable microwave shielding by dip-coating a melamine sponge with a mixture solution of VGCNF and EP. Increased EP addition to the dipping solution resulted in a decrease in the weight loading ratio (m VGCNF / m sponge) of VGCNF into the sponge from 66.2 to 15.7 wt%. For the shape memory effect, increased EP filling resulted in an improved compression fixity ratio of more than 99% but a decreased compression recovery ratio of less than 90%. By introducing ethanol (EtOH), adjustable EP filling into the sponge was achieved. Thus, moderate addition of EP into EtOH, such as 20:1 (v/v , EtOH/EP), could achieve good shape memory effects (compression fixing and recovery ratios of approximately 95% and 94%, respectively) and a high VGCNF loading ratio of approximately 58.4 wt%. For microwave shielding, 20:1 VGCNF@EP-MS showed an adjustable shielding effectiveness (SE) from 18 to 38 dB in the frequency range of 8.2 – 12.4 GHz, which was achieved using the shape memory effect for different thickness compressions and fixing. This VGCNF@EP-MS could be used for different extents of targeted electromagnetic signal adjustment in smart electromagnetic shielding. [Display omitted] • Ethanol was introduced into the dipping solution for fine filling adjustment of epoxy into the sponge matrix. • Dip-coating of shape memory epoxy was demonstrated effective to achieve a fixing for a desired compression thickness. • Deep compression of VGCNF@EP-MS is required for effective adjustment in shielding effectiveness. • ●20:1 VGCNF@EP-MS showed an adjustable microwave shielding in a large range from 18 dB to 38 dB. [ABSTRACT FROM AUTHOR]

(Li1+, Al3+) co-doped Ni 0.5 Zn 0.5 Fe 2 O 4 ferrites, Ni 0.5-x Zn 0.5-x Li x Al x Fe 2 O 4 (x = 0.000, 0.025, 0.050 and 0.100), were synthesized by the sol-gel auto-combustion method. X-ray diffraction (XRD), field emission scanning electronic microscope (FESEM), vibrating sample magnetometer (VSM) and LCR meter were used to investigate the structural, magnetic and dielectric properties. Results of XRD and SEM indicate that both doping amount and calcination temperature play significant roles in crystal structure and grain growth. Also, it can be observed that the saturation magnetization and the coercivity change in a noticeable manner. The Ni 0.475 Zn 0.475 Li 0.025 Al 0.025 Fe 2 O 4 ferrite sintered at 1200 °C has a relatively low coercivity value (62.93 Oe) and the largest saturation magnetization (110.95 emu/g). Besides, dielectric behavior is also improved by Li1+ and Al3+ co-doping. Image 1 • XRD result confirmed the formation of cubic spinel structure. • Enhanced magnetic and dielectric properties were modulated by Li1+ and Al3+ ions. • Variation of M s and H c was explained by cation distributions. • Enhanced dielectric behavior was confirmed by Nyquist diagram analysis. [ABSTRACT FROM AUTHOR]

(Li1+, Zn2+ and La3+) co-substituted NiFe 2 O 4 ferrite ceramics (Ni 0.8-x Zn x Li 0.1 La 0.1 Fe 2 O 4 , x = 0.0, 0.2, 0.4, 0.6, 0.8) were prepared by the sol-gel auto-combustion method. The structural properties were investigated by X-ray diffraction and field emission scanning electronic microscope techniques. Vibrating sample magnetometer and LCR meter were used to probe magnetic and dielectric properties. A relatively high value of saturation magnetization (105.94 emu/g) can be achieved in Ni 0.4 Zn 0.4 Li 0.1 La 0.1 Fe 2 O 4 sample sintered at 1100 °C. In addition, the soft magnetic properties are also enhanced due to a reduced coercivity value. Also, dielectric behavior is improved and all the results show that co-substitution with Li1+, Zn2+ and La3+ ions as well as modulation via Zn2+ ions has a great impact on the properties of Ni ferrites. [ABSTRACT FROM AUTHOR]

Graphene nanoribbons (GNRs) are potential nanomaterial electromechanical oscillators because of their outstanding mechanical and electronic properties. Double-layer GNRs (DLGNRs), which are two-layer finite-wide counterparts of crystalline graphene sheets coupled to each other via van der Waals interaction forces, present two kinds of vibrational modes in flexural wave propagation. These two modes are defined as the in-phase mode and anti-phase mode. In this study, based on the nonlocal Timoshenko beam theory and Winkler spring model, the wave propagation characteristics of DLGNRs embedded in an elastic matrix are investigated by dividing the vibrational mode into the in-phase mode and anti-phase mode. This will provide more accurate guidance for the application of DLGNRs. When the nonlocal effects and elastic matrix are considered, three critical frequencies are found. These are defined as the cutoff, escape, and low-cutoff frequencies. Moreover, the results show that the wave propagation characteristics of embedded DLGNRs are significantly influenced by nonlocal parameters and the Winkler foundation modulus. [ABSTRACT FROM AUTHOR]

Vibration characteristics of double-walled carbon nanotubes (DWCNTs) with conveying fluid are analyzed based on the Euler–Bernoulli beam theory and using the wave propagation approach. The DWCNTs are considered as two nanotube shells coupled through the van der Waals interaction between them. The influences of internal moving fluids, such as flow velocity and mass density of fluids, on the vibration frequency of DWCNTs and the DWCNTs embedded in an elastic matrix are investigated in detail. The effect of matrix surrounding carbon nanotubes is considered as a spring element defined by the Winkler model. In this paper, we consider the double-walled nanotubes with an inner diameter of 2.2 nm and an outer diameter of 3.0 nm. According to this analysis, the numerical results indicate that the vibration frequency for the first mode (mode 1) reduces to zero at a critical flow velocity in the case of higher flow velocity, which coincides with the previous study based on a single beam model. The critical flow velocity is largely affected by the fluid properties and the vibration modes. [ABSTRACT FROM AUTHOR]

Carbon nanotubes may hold scientific promise in nanotechnology as nanopipes conveying fluid. In this paper, the wave propagation in double-walled carbon nanotubes (DWCNTs) conveying fluid is studied based on the Euler–Bernoulli beam theory. The influences of internal moving fluids, such as flow velocity and mass density of fluids, on the sound wave propagation of DWCNTs or the DWCNTs embedded in an elastic matrix are investigated in detail. The DWCNTs are considered as a two-shell model coupled together through the van der Waals interaction between two adjacent nanotubes. According to the proposed theoretical approach, the results indicate that fluid flow through carbon nanotubes affects the wave speed and the critical frequency in the carbon nanotubes. The amplitude ratios of the inner to outer nanotubes are largely affected by the fluid velocity and density when the vibrational frequency in nanotubes is larger than 1.5 Hz. The theoretical investigation may give a useful reference for potential application and design of nanoelectronics and nanodevices. [ABSTRACT FROM AUTHOR]

We present an approach for efficient, accurate calculations of the elastic wave properties of three-dimensional periodic solid-solid media with cubic lattice structures based on the principle that the elastic wave should be uniform when averaged over length scales much larger than the size of the scatterers. Utilizing the fact that the media has the same pure mode properties as natural crystal with the corresponding lattice structure, we derive formulas for effective velocities propagating along and normal to the lattice axis, from which three independent effective elastic moduli are calculated, respectively. Effective velocities propagating along any directions can be calculated with this method, which captures the multiple scattering and the structure of the periodic medium. The results agree well with those calculated directly from the slope of the corresponding bands near the Γ point of the first Brillouin zone and are in good agreement with previous isotropic theory at high-symmetry directions. [ABSTRACT FROM AUTHOR]

Wave propagation approach of single- and double-walled carbon nanotubes conveying fluid is presented through the use of the continuum mechanics. A simplified Flügge shell equations are proposed as the governing equations of motion for carbon nanotubes studied here. For the double-walled nanotubes, the deflection of nested tubes is considered to be coupled through the van der Waals interaction between two adjacent nanotubes. Effects of filled fluid property and nanotube diameter on the wave propagation are investigated and analyzed based on the proposed elastic continuum model. The theoretical investigation may give a useful reference for potential design and application of nanoelectronics and nanodevices. [ABSTRACT FROM AUTHOR]

• A data-driven prognostic approach is proposed for bearing health management. • A novel health indicator (HI) to fuse similarity-based multi-scale features is proposed. • Grasshopper optimization algorithm is integrated to adaptively tune hyperparameters. • The proposed prognostic approach is with high accuracy and generalizability. Remaining useful life (RUL) prediction plays a crucial role in bearing health management which can guarantee the rotating machinery systems' safety and reliability. This paper promotes the capability of bearing health management by proposing a novel data-driven prognostic approach. The proposed methodology reveals the underlying deterioration progression by constructing a new health indicator (HI) that fuses distribution-similarity-based multi-scale features. More specifically, a graph named WDgram, to represent the distribution similarity between the analyzed signal and healthy reference at different frequency scales, is developed first using the 1/3-binary tree structure and Wasserstein distance (WD). Then the high-dimensional multi-scale features are fused by the multiobjective grasshopper optimization algorithm (MOGOA) to optimize the HI's monotonicity, robustness, and tenability. By taking advantage of the WDgram and MOGOA, the novel HI is able to thoroughly reveal the underlying degradation characteristics and alleviate random fluctuations which frequently decrease the accuracy of RUL estimation. Subsequently, a gated recurrent unit network, incorporated with the grasshopper optimization algorithm (GOA) to adaptively determine some hyperparameters, is established with high predictive accuracy and generalizability. Experimental validation is conducted to prove the effectiveness of the proposed method. High accuracy and generalizability can be obtained by the proposed method, demonstrating its substantial advantages in health management for rotating machinery systems. [ABSTRACT FROM AUTHOR]

• A STPV system employing selective metafilm as both absorber and emitter is studied. • Both metafilm absorber and emitter are optimized for enhancing STPV efficiency. • A cavity reflector is proposed for recycling thermal emission from the absorber. This work performs a detailed theoretical analysis for low-concentration solar thermophotovoltaic (STPV) system with both solar absorber and thermal emitter made of previously-developed selective metafilms along with a cavity reflector for performance enhancement. When paired with an InGaAsSb cell, the initial metafilm structure shows an STPV system efficiency of 7.1% at 50 suns, where about half of the incident solar energy is lost through the thermal emission from the top surface of the absorber according to energy loss analysis. In order to enhance the STPV system performance, the metafilm layer thicknesses of the solar absorber and those of the thermal emitter are optimized at 50 suns, increasing the STPV system efficiency from 7.1% to 10.2%. Moreover, a cavity reflector above the absorber is considered to recycle the infrared photons emitted from the top surface of the absorber. The effects of the size and the reflectivity of the cavity reflector on the efficiency are discussed. The results show that, the efficiency of the optimized metafilm based STPV system at 50 suns can be increased from 10.2% to 17.4% with a cavity made of ideal reflectors. [ABSTRACT FROM AUTHOR]

As a benchmark triple‐conducting cathode, BaCo0.4Fe0.4Zr0.1Y0.1O3−δ (BCFZY) has been widely investigated for protonic ceramic fuel cells (PCFC) in recent years. However, the reported electrochemical performance of BCFZY cathode differs, which is determined in this work to originate from the thermal expansion mismatch between BCFZY and electrolyte. Accordingly, two strategies for enhanced thermo‐mechanical compatibility are examined: impregnation and thermal expansion offset. In contrast to the impregnation of BCFZY nanoparticles on electrolyte backbones that only helps improve electrochemical performance, negative thermal expansion oxide Sm0.85Cu0.15MnO3−δ (SCM)‐offset BCFZY exhibits superior durability and activity simultaneously. Specifically, the polarization resistance decay rate of the SCM‐offset BCFZY is only ~0.2%/100 h, compared with ~18.75%/100 h for "impregnated BCFZY." Moreover, pure SCM generates moderate cathodic performance (area‐specific resistance = 0.11 Ω cm2, 700 °C), X‐ray diffraction and transmission electron microscopy reveal an in‐situ formed intergranular Ba2Cu3SmO7−δ phase at the boundaries of BCFZY and SCM. Thus, SCM can serve as a "three‐effect" additive, i) offset thermo‐expansion, ii) strengthen electrode structure and adhesion, and iii) provide acceptable oxygen‐reduction‐reaction activity, being favorable for superior performance. A PCFC using a SCM‐offset BCFZY cathode achieves the highest power density (1455 mW cm−2) yet recorded for PCFCs with BCFZY‐based cathodes. [ABSTRACT FROM AUTHOR]

Various deep learning methodologies have recently been developed for machine condition monitoring recently, and they have achieved impressive success in bearing fault diagnostics. Despite the capability of effectively diagnosing bearing faults, most deep learning methods are tremendously data-dependent, which is not always available in industrial applications. In practical engineering, bearings are usually installed in rotating machinery where speed and load variations frequently occur, resulting in difficulty in collecting large training datasets under all operating conditions. Additionally, physical information is usually ignored in most deep learning algorithms, which sometimes leads to the generated results of low compliance with the physical law. To tackle these challenges, a novel Physics-Informed Residual Network (PIResNet) is proposed for learning the underlying physics that is embedded in both training and testing data, thus providing a physical consistent solution for imperfect data. In the proposed method, a physical modal-property-dominant-generated layer is adopted at first to generate the modal-property-dominant feature. Then, a domain-conversion layer is constructed to enable the feasibility of extracting the discriminative bearing fault features under varying operating speed conditions. Lastly, a parallel bi-channel residual learning architecture that can automatically extract the bearing fault signatures is meticulously established to incorporate the bearing fault characteristics. Experimental datasets under variable operating speeds and loads, and time-varying operating speeds are utilized to demonstrate the superiority of the PIResNet under non-stationary operating conditions. [ABSTRACT FROM AUTHOR]

Introduction/Aim: To assess the effectiveness and safety of Traditional Chinese patent medicines (TCPMs) for managing impaired glucose tolerance (IGT). Methods: Seven databases were searched to identify eligible trials published from incepting to May 1, 2016. Randomized controlled trials (RCTs) involving TCPM for IGT with a minimum follow-up duration of 6 months were included for analysis. Data extraction and quality assessment were performed by two reviewers independently. Data synthesis was analyzed using Review Manager 5.3 software. Subgroup analysis was carried out to assess the robustness of results of meta-analysis. Results: Eighteen trials with a total of 3172 participants met the inclusion criteria. The methodological quality of the RCTs was variable. Comparing with receiving lifestyle modification (LM) alone, TCPM plus LM was significantly better at reducing the incidence of diabetes (risk ratio [RR] 0.45; 95% confidence interval [CI] 0.36–0.57, p  < 0.00001) and normalizing the blood glucose (RR 0.72; 95% CI 0.64–0.82, p  < 0.00001). TCPM plus LM was superior in decreasing the levels of 2hPG, body mass index (BMI), fasting insulin, and 2 h insulin compared with LM alone (2hPG: mean difference [MD] −1.13; 95% CI −1.68 to −0.58, p  < 0.0001; BMI: MD −0.42; 95% CI −0.71 to −0.14, p  = 0.004; fasting insulin: MD −2.44; 95% CI −3.79 to −1.09, p  = 0.0004; and 2 h insulin: MD −8.26; 95% CI −8.47 to −8.05, p  < 0.00001). Compared with placebo plus LM, TCPM plus LM was superior in reducing diabetes (RR 0.54; 95% CI 0.42–0.69, p  < 0.00001) and normalizing blood glucose (RR 0.55; 95% CI 0.41–0.73, p  < 0.00001; the interventions were also associated with a decline in the two-hour postprandial blood glucose (2hPG) levels (MD −1.45; 95% CI −2.11 to −0.79, p  < 0.0001) and BMI levels (MD −1.12; 95% CI −2.00 to −0.24, p  < 0.0001). There were no significant differences in adverse events between two groups. Subgroup analysis found no significant difference in overall effects among all study characteristics, indicating that the overall effects were stable. Conclusions: The study indicated that TCPM combined with moderate lifestyle modification had significant effect on IGT. Further studies are needed to provide more reliable evidence. The PROSPERO registration is No. CRD42016039312. [ABSTRACT FROM AUTHOR]

In light of the rapid increasing demand for high-precision ultrasonic technologies for damage detection in composite structures, it is necessary to give a further study on the ultrasonic attenuation characteristics, with consideration of the combined effects of material anisotropy and viscoelasticity, and the frequency characteristics of the individual attenuation component. In the present paper, based on the time-domain finite element analysis of ultrasonic wave propagation in a two-layered fiber/matrix composite material, a new method is presented. In the method, by means of extracting the individual attenuation components (viscoelastic attenuation, scattering attenuation due to interface defects, and energy dissipation at the interface) from the overall attenuation respectively, the variation behavior of them with material anisotropy and viscoelasticity, and incident wave frequency, are quantitatively evaluated. The change of proportion of individual attenuation components in overall attenuation under different conditions are also investigated. From the results, the energy loss at the interface is always a major part in ultrasonic attenuation characteristics. Each attenuation component shows frequency dependence, especially the viscoelastic attenuation and energy dissipation at the interface. The simulation results also clarified the detailed effect mechanism of material viscoelasticity and anisotropy on the attenuation characteristics, which will encourage the further development of attenuation measurements for damage detection in composite structures. [ABSTRACT FROM AUTHOR]

Despite much attention, the path of the highly consequential primary proton transfer in the light-driven ion pump bacteriorhodopsin (bR) remains mysterious. Here we use DNP-enhanced magic angle spinning (MAS) NMR to study critical elements of the active site just before the Schiff base (SB) deprotonates (in the L intermediate), immediately after the SB has deprotonated and Asp85 has become protonated (in the Mo intermediate), and just after the SB has reprotonated and Asp96 has deprotonated (in the N intermediate). An essential feature that made these experiments possible is the 75-fold signal enhancement through DNP. 15N(SB)-1H correlations reveal that the newly deprotonated SB is accepting a hydrogen bond from an alcohol and 13C-13C correlations show that Asp85 draws close to Thr89 before the primary proton transfer. Concurrently, 15N-13C correlations between the SB and Asp85 show that helices C and G draw closer together just prior to the proton transfer and relax thereafter. Together, these results indicate that Thr89 serves to relay the SB proton to Asp85 and that creating this pathway involves rapprochement between the C and G helices as well as chromophore torsion. [ABSTRACT FROM AUTHOR]

La 1− x Sm x − y Sr y CoO 3−δ (LSSC; x = 0.475, 0.650, 0.825, y = 0.35, 0.40, 0.45) compounds, which have the same compositions as the La 0.7 Sr 0.3 CoO 3−δ (LSC) and Sm 0.5 Sr 0.5 CoO 3−δ (SSC) mixture (corresponding mole ratio is 3:1, 1:1 and 1:3, respectively), are synthesized through a conventional solid-state reaction and characterized by X-ray diffraction, thermal expansion coefficient, X-ray photoelectron spectrometer and electrical conductivity measurement, as well as the electrochemical impedance spectra and single cell performance measurement. Interestingly, the experimental results reveal that with the linear increase of y in LSSC, the conductivity of the corresponding samples does not alter linearly but reaches a peak when y = 0.35, namely, the maximum electrical conductivity enhancing from 2148 S cm −1 (LSC, y = 0.30) and 1802 S cm −1 (SSC, y = 0.50) to 2750 S cm −1 ( y = 0.35). In addition, this turning point coincidently corresponds to the structure transition from hexagonal ( y = 0.35) to orthorhombic ( y = 0.40). Furthermore, comparing with LSC and SSC, the cathode polarization resistance (R P ) decreases by about 50% and 38%, respectively, after employing the LSSC ( y = 0.40) compound as cathode at 800 °C and 0.21 atm p(O 2 ), which also leads to an increment of 49% and 31% respectively in peak power density. These results imply promising applications of such effective cathodes for intermediate temperature solid oxide fuel cells. [ABSTRACT FROM AUTHOR]

A new design of cathode current-collecting element (CCCE) based on SmSrCoO, which contains gas channels and an array of truncated-pyramid-shaped contact tips, is synthesized through die pressing followed by a conventional solid-state reaction for intermediate-temperature solid oxide fuel cells (IT-SOFCs). This configuration could not only maintain the high electronic conductivity of the material to ensure the efficiency of current collecting, but also improve the gas diffusion rate at the cathode side. The height h of the channel tips on the CCCEs reaches approximately 60, 120, and 240 μm, respectively, which results in the variation in polarization resistance ( R ) more significantly than the contact area of the tips does. The experiments show that the R of the symmetric cells decreased from 0.267 to 0.060 Ω cm at 800 °C after employing the CCCE with modified parameters. In addition, the measured peak power density of the individual cell is enhanced from 111 to 145 mW cm at 800 °C. The results show that the cathode current-collecting elements may be potentially useful for applications in IT-SOFCs. [ABSTRACT FROM AUTHOR]

Barium titanate (BT) nanoparticles were fabricated using sol-gel method, and then immobilized onto the surface of carbon nanotubes (CNTs) to fabricate heterogeneous barium titanate@carbon nanotube (BT@CNT) nanocomposites. The electromagnetic (EM) wave absorption ability increased as the weight fraction of BT@CNT increased. The BT@CNT 30 wt.% nanocomposites with thickness of 1.1 mm showed a minimum reflection loss (R.L.) of ∼ − 37.2 dB (> 99.98% absorption) at 13.9 GHz with a response bandwidth of 1.6 GHz (12.3 ∼ 13.9 GHz), and were the best absorber when compared to similar nanocomposites with different thicknesses. The relationship between conductivity and EM wave absorption properties was also discussed. Appropriate conductivity also plays an important role to obtain optimum absorption performance. BT@CNT nanocomposites exhibited significant absorption ability, and this indicates that they can be utilized as an effective EM wave absorber material. Left: absorption performance and response bandwidth of BT@CNT 30 wt.% nanocomposites with various thicknesses. Right: TEM image of BT@CNT. [ABSTRACT FROM AUTHOR]

• Three reported MOFs exhibit versatile structures with 2D and 3D frameworks. • Ligand exhibits different coordination mode in these three MOFs. • Zn-MOF is explored as an effective catalyst for the cycloaddition reaction of CO 2 with epoxides into cyclic carbonates. • The synergistic catalysis of Lewis acidic Zn2+ ions, Lewis basic -NH- groups and hydrogen bond donors of -NH- could play an efficient role in this cycloaddition reaction. By employing a C 3 -symmetric ligand, 3,3′,3′'-[1,3,5-benzenetriyltris- (carbonylimino)]tris-benzoic acid (H 3 L), three metal-organic frameworks formulated as {Na 4 [Zn 3 (L) 2 (µ 3 -OH)(µ 2 -OH) 3 ]·3DMF} n (1), {[Ca 2 (L)(MeOH) 2 (DMF) 3 ]·Cl} n (2) and [Sr 2 (L)(H 2 O) 2 (DMF)Cl] n (3) have been solvothermally synthesized and structurally characterized by IR, PXRD and X-ray single crystal diffraction analyses. Complex 1 features a 2D twofold interpenetrated structure in which the [Zn 3 (µ 3 -OH)(µ 2 -OH) 3 (CO 2) 3 O 3 ] subunit acts as a 6-connected node and the L3− ligand as a 3-connected node, exhibiting a binodal (3, 6)-connected topology with a {43} 2 {43.612} point symbol. Complex 2 shows a 2D double-layered structure, exhibiting a (3,6)-connected {43} 2 {46.66.83} topology based on a centrosymmetric tetranuclear [Ca 4 (CO 2) 6 ] subunit as a 6-connected node and the L3− ligand as a 3-connected node. Complex 3 exhibits an extended 3D framework with a {46} 2 {412.612.84} topology in which the centrosymmetric {Sr 4 (CO 2) 6 [(O^O) acylamide ] 2 } subunit performs as an eight connected node and the L3− ligand as an unusual 4-connected node. Complex 1 is explored well as a catalyst for the cycloaddition reaction of CO 2 with epoxides into cyclic carbonates under the reaction conditions of 70°C, 1 bar atmosphere and free solvent. The efficient catalytic ability of 1 perhaps attributes to the high density of Lewis acidic sites of Zn2+ and Lewis basic -NH- groups in 1. Beside the basic function, the -NH- group in 1 can also perform as hydrogen bond donor (HBD) for the activation of epoxide in the catalytic process. A plausible mechanism for synergistic catalysis is proposed for the cycloaddition reaction. [Display omitted] [ABSTRACT FROM AUTHOR]

Polymer melt blending has become a main and important method to modify polymer materials for overcoming defects and obtaining excellent performance. The mechanical properties, compatibility, tribological properties and modification mechanisms of polyphenylene sulfide (PPS) alloys have been investigated over the last decades. However, there are few researches on PPS/polyvinylidene fluoride (PVDF) alloys, and material researchers have paid little attention to the manufacture and properties of PPS/PVDF alloys. In our research, the morphology, thermal properties and mechanical properties of PPS/PVDF alloys were first studied. PPS/PVDF alloys were prepared by a simple polymer melt blending. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the morphology of PPS/PVDF alloys. It was found that the PPS/PVDF alloys had a “sea-island” structure with a poor adhesion at the interface between the PVDF phase and PPS matrix. The addition of PPS may also promote the transformation of α-phase to β-phase in PVDF. The thermal properties of PPS/PVDF alloys were confirmed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It indicated the addition of PVDF would accelerate the crystallization of PPS and increase the crystal perfection of PPS. It was clearly that the thermal stability of PPS/PVDF alloys could be improved by the addition of PVDF especially when the PVDF content is lower than 20 wt %. When the content of PVDF was only 5 wt %, the tensile strength and tensile modulus of PPS/PVDF alloys had a significant improvement compared with pure PPS. Furthermore, it was also found that the addition of PVDF could also increase breaking elongation rate in a small degree. [ABSTRACT FROM AUTHOR]

Rapid oxygen ion conduction, which is important in solid oxide fuel cell (SOFC) electrolytes, is often dramatically hindered by the presence of even small concentrations of impurities such as SiO 2 , which is ubiquitous in ceramic processing. In this study, rapid degradation of the grain boundary (GB) conduction of Ce 0.8 Sm 0.2 O 1.9 (SDC) is observed with increasing SiO 2 addition from 0 to 1 wt%. Nearly complete GB conduction recovery is achieved through synergy between CaO and ZnO in the SDC + x wt% Si systems. Scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) demonstrate the formation of a Ca-, Si-, and Sm-containing secondary phases, which is related to the enhancements in GB conductivity and reductions in activation energy. The scavenging effect of CaO is verified in this study and ZnO is observed to promote the scavenging reaction. Compared with the single-addition case (CaO/ZnO), the much higher SiO 2 impurity tolerance of the combined system suggests the commercial potential of the “scavenger + promoter” strategy presented in this work. [ABSTRACT FROM AUTHOR]

Understanding the Zn diffusion behavior in GaSb is very important to accurately control the distribution of Zn during the fabrication of photoelectric devices. The surface concentration and effective surface diffusivity are two key parameters for modeling the Zn profile in GaSb. The experimental results indicated that when the diffusion temperature and time are kept unchanged, the diffusion profiles with pure Zn, Zn-Sb, and Zn-Ga sources differ in the surface concentration and effective surface diffusivity. To quantitatively explain the effects of source composition on the two parameters, the relationship between the two parameters and the vapor pressure surrounding the GaSb wafer in the diffusion process was deduced based on a surface-equilibrium assumption and the substitutional-interstitial mechanism. The Ga/Sb/Zn ternary phase diagram was calculated and discussed for determining the vapor pressures in different source cases. The ratio of surface concentrations and that of effective surface diffusivities between different sources were obtained to quantitatively explain the experiment results. The theoretical and experimental results both indicated that adding Sb to pure Zn source keeps the surface concentration unchanged while slightly decreases the effective surface diffusivity, and that adding Ga to pure Zn source significantly decreases both the surface concentration and effective surface diffusivity. [ABSTRACT FROM AUTHOR]

As promising candidates for thermophotovoltaic energy conversion systems, epitaxial thin film III–V cells have gained increasing attention due to their potential for reduced weight. However, few studies have been done to date to enhance the performance of epitaxial single crystal GaSb thin film cells. In this work, the internal quantum efficiencies of epitaxial single crystal GaSb thin film cells with Zn-diffused and epitaxial p–n junctions were predicted with models verified using the corresponding experimental results. The results are the first to indicate that, for the former, when the base region thickness is approximately equal to minority carrier diffusion length, the maximal IQE can be obtained and it is notably higher than the IQE of GaSb bulk cell at wavelengths from 800 to 1700 nm. Reducing bottom surface recombination velocity and increasing hole Shockley–Read–Hall lifetime could also increase the IQE. While for the latter, the results demonstrated that the optimal base region thickness is also approximately equal to minority diffusion length, and reducing emitter region thickness will increase the IQE when the base region is optimized. The comparison of the two optimized GaSb thin film cells showed that the GaSb thin film cell with epitaxial p–n junction has a higher IQE. [ABSTRACT FROM AUTHOR]

A fish-basket-shaped [Co24] cluster, [Co24(μ3-O)4(ampc)4(μ3-OH)4(μ2-OH)4(NO3)5(HCO2)22(H2O)10]·[(HCO2)·2(CH3OH)·x(H2O)], was woven by bridging oxygen atoms from O2−, OH−, NO3− and HCO2− groups, and stabilized terminally by a semi-rigid organic ligand 4′,4′-[(dimethylamino)dimethylene]-bis[(1,1′-biphenyl)-2-carboxylate] (ampc−). Magnetic analyses indicate that the [Co24] cluster exhibits two types of spin canting orders, spin flop and a small hysteresis with a coercive field of ca. 661 Oe and a remanent magnetization of 0.466 Nβ. [ABSTRACT FROM AUTHOR]

The electroactive nanocomposite films were fabricated using polyurethane (PU) with modified carbon nanotubes (CNTs) as the filler. The CNTs were modified using microwave-induced polymerization route and they were found to be highly dispersed in polar solvents such as dimethylformamide. The modified CNTs were characterized using transmission electron microscopy, field emission scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. To evaluate these films we mainly focused on electrical properties such as actuation behavior, resistivity, impedance analysis, and space charge measurements. We found that the PU/CNT films bent toward the cathode when an electric field was applied and they reverted to its original position when the electric field was removed. Upon the incorporation of CNTs as the filler for the polymer, the electrical properties of the films improved significantly. Asymmetric charge accumulation was observed from space charge measurements in some of the films and this explains the bending deformation and the actuation behavior. [ABSTRACT FROM AUTHOR]

The complexes [Ag12(Spz)12(N-triphos)2][Ag3(Spz)3(Ntriphos)] 2·(DMF)6 (1) and [Ag18(Spz)12(N-triphos)4(CF3CO2)6] (2) were synthesized and structurally characterized by x-ray diffraction [HSpz = pyrazine-2-thiolate, N-triphos = tris((diphenylphosphanyl)- methyl)amine]. The central [Ag6] ring with chair-conformation in 1 and the ideally octahedral [Ag6] cluster core in 2 are both stabilized by the tripodal building units of neutral [Ag3(Spz)3(N-triphos)] compound. The Ag···Ag distances of the [Ag6] moieties in 1 and 2 are 3.07 and 2.81 Å, respectively, exhibiting intermetallic interactions, which can enhance the stability of [Ag6] conformations. In addition, the π···π interactions between parallel pyrazine rings could impose on the building and the Ag···Ag interactions of these Ag-S clusters [ABSTRACT FROM AUTHOR]

The gearbox is a vital component for rotating machinery and has been used in many critical engineering applications. Surface wear is a common but inevitable phenomenon during the lifespan of the gearbox. Its propagation can result in some catastrophic failures and cause unexpected economic loss. Therefore, it is vital to evaluate the degradation process of the gear system caused by surface wear propagation in order to make reliable predictive maintenance-based decisions to ensure the safe operation of the gearbox transmission system. The vibration analysis technique is a prevailing tool for rotating machine condition monitoring. However, research on vibration-based gear wear monitoring is relatively rare as the dynamic interactions between gear surface wear and gear system dynamic characteristics would produce complex gear dynamic responses and vibration features. Therefore, this paper presents a novel similarity-based status characterization methodology for gear wear monitoring. In this proposed methodology, a novel gear wear monitoring indicator is developed to evaluate gear tooth contact characteristics at different wear severities, which could significantly benefit gear systems' health management. The effectiveness of the proposed method for gear wear propagation process monitoring is presented and proven through a series of run-to-failure tests with different lubrications and operational conditions. [ABSTRACT FROM AUTHOR]

The electromagnetic wave absorption properties of single- and double-layer silver nanoparticle/carbon nanotube (Ag/CNT) nanocomposites were evaluated. The reflection loss (R.L.) of the samples was calculated based on the measured complex permittivity and permeability. The double-layer composites constructed from CNT 30 wt.% and Ag/CNT 30 wt.% with total thickness of 3.3 mm showed a minimum R.L. of ∼−52.9 dB (over 99.999% absorption) at 6.3 GHz. The bandwidth of reflection loss less than −10 dB was observed at 3 regions, with wideness of 3.5, 0.8, and 1.5 GHz. Thin absorber with large R.L. and wide response bandwidth at low and high frequency regions can be obtained with double-layer composites. The capability to modulate the absorption and bandwidth of these samples to suit various applications in different frequency bands indicates that these nanocomposites could be an excellent electromagnetic wave absorber. [ABSTRACT FROM AUTHOR]

Vapor-grown carbon nanofiber (VGCNF)/water-borne epoxy (WEP) and SiO2/WEP composites were successfully synthesized via freeze drying and hot-press molding. VGCNFs were mixed directly with a WEP emulsion, while SiO2 was synthesized by in situ hydrolysis of TEOS solution (3-triethoxysilylpropylamine (KH550): tetraethoxysilane (TEOS): absolute ethanol = 1:5:20, w/w/w) dispersed in the WEP emulsion. WEP composites were obtained from these mixtures by freeze drying and compressing under a pressure of 10 MPa at 120°C for 2 h. The morphology and mechanical properties of the WEP composites were investigated by transmission electron microscopy, scanning electron microscopy, dynamic mechanical analysis and tensile testing. The shape memory (SM) properties of the WEP composites were evaluated by fold-deploy SM testing. The effects of filler content and recovery temperature on the SM properties were revealed through systematic variation. The results confirmed that VGCNF and in situ hydrolyzed SiO2 were homogenously dispersed and incorporated into the WEP matrices. Thus, significant improvements in the mechanical and SM properties of the composites were achieved. POLYM. COMPOS., 36:1712-1720, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The electromagnetic wave absorption properties of double-layer barium titanate/carbon nanotube (BTO/CNT) nanocomposites were evaluated. The BTO/CNT nanomaterials were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. The reflection loss ( R.L. ) of the samples was calculated based on the measured complex permittivity and permeability. The minimum R.L. of single-layer BTO/CNT 30 wt% nanocomposites sample with a thickness of 1.1 mm reached ~−30.3 dB (over 99.9% absorption) at 13.8 GHz, and the bandwidth of the reflection loss less than −10 dB (over 90% absorption) was 1.5 GHz. The double-layer composites consist of BTO/CNT 30 wt% (absorption layer) with thickness of 1.0 mm and BTO 30 wt% (matching layer) with thickness of 0.3 mm showed a minimum R.L. of ~−63.7 dB (over 99.9999% absorption) at 13.7 GHz, and the bandwidth of the reflection loss less than −10 dB was 1.7 GHz. Wider response bandwidth, >1.7 GHz also can be achieved with different designs of double-layer absorbers. The R.L. significantly improved and wider response bandwidth can be obtained with double-layer composites. The capability to modulate the absorption and bandwidth of these samples to suit various applications in different frequency bands indicates that these nanocomposites could be an excellent electromagnetic wave absorber. [ABSTRACT FROM AUTHOR]

A Lattice Monte Carlo (LMC) method was employed to predict the effective thermal conductivity (ETC) of closed-cell aluminum foams with porosities between 0.828 and 0.894 through a cubic unit model. The numerical results demonstrated a linear dependency on the relative density when the cell wall thermal conductivity (CWTC) was set as that of pure aluminum; the dependency had large deviations from the measured ETCs obtained via a steady-state comparative method. To characterize the actual CWTC, its relationship with the ETC was deduced, and its value was determined through the measured ETC. On the other hand, the cubic unit model was improved with consideration of the plateau borders characterized through Image-Pro software. With the corrected CWTC and the improved cubic unit model, the numerical results agreed well with the measured results. Hence, the LMC method can be used to predict the ETC of closed-cell aluminum foams accurately through a cubic unit model, provided that the relative density, the CWTC and the plateau borders are taken into account. [ABSTRACT FROM AUTHOR]

Background. Single nucleotide polymorphisms (SNPs) in genes encoding microRNAs may play important role in the development of gastric cancer. It has been reported that common SNPs rs2910164 in miR-146a and rs11614913 in miR-196a2 are associated with susceptibility to gastric cancer. The published results remain inconclusive or even controversial. A meta-analysis was conducted to quantitatively assess potential association between the two common SNPs and gastric cancer risk. Methods. A comprehensive literature search was performed in multiple internet-based electronic databases. Data from 12 eligible studies were extracted to estimate pooled odds ratios (ORs) and 95% confidence intervals (95% CI). Results. C allele of rs2910164 is associated with reduced gastric cancer risk in heterozygote model and dominant model whereas rs11614913 indicates no significant association. Subgroup analysis demonstrates that C allele of rs2910164 and rs11614913 may decrease susceptibility to diffuse type gastric cancer in dominant model and recessive model, respectively, while rs11614913 increased intestinal type gastric cancer in dominant model. Conclusion. SNPs rs2910164 and rs11614913 might have effect on gastric cancer risk in certain genetic models and specific types of cancer. Further well-designed studies should be considered to validate the potential effect. [ABSTRACT FROM AUTHOR]

The rapidly increasing use of engineered nanoparticles (NPs) in consumer products inevitably leads to their greater presence in wastewater treatment plants. In this study, the effects of zinc oxide nanoparticles (ZnO-NPs) on system performance and bacterial community dynamics of biological wastewater treatment in a lab-scale sequencing batch reactor were evaluated, along with their fate within the system. It was found that ZnO-NPs caused poor settleability of the activated sludge and a significant decrease in the removal of nitrogen and phosphorus over time. Denaturing gradient gel electrophoresis analysis revealed that the bacterial community in the activated sludge became less diverse after exposure to ZnO-NPs. In addition, the production of extracellular polymeric substances (EPS) increased, with the EPS forming a tight matrix to protect the cells from the NPs. The NPs were removed very effectively from wastewater, mainly via sorption to the sludge. [ABSTRACT FROM AUTHOR]

Barium titanate/carbon nanotube (BTO/CNT) hybrid nanocomposites were fabricated by sol–gel method. The BTO/CNT hybrid nanomaterials were characterized using X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, Raman and X-ray photoelectron spectroscopy. The BTO/CNT hybrid nanomaterials were then loaded in paraffin wax with different weight percentage, and pressed into toroidal shape with thickness of 1.0 mm to evaluate their complex permittivity and complex permeability using vector network analyzer. The reflection loss of the samples was calculated according to their measured complex permittivity and permeability. The minimum reflection loss of the BTO/CNT 60 wt.% hybrid nanocomposites sample with a thickness of 1.0 mm reached 29.6 dB (over 99.9% absorption) at 13.6 GHz, and also exhibited a wide response bandwidth where the frequency bandwidth of the reflection loss of less than −10 dB (over 90% absorption) was from 12.1 to 13.8 GHz. The BTO/CNT 60 wt.% hybrid nanocomposites with thickness of 1.1 mm showed a minimum reflection loss of ∼−56.5 dB (over 99.999% absorption) at 13.2 GHz and was the best absorber when compared with the other samples of different thickness. The reflection loss peak shifted to lower frequency and wider response bandwidth can be obtained as the thickness of the samples increased. The capability to modulate the absorption band of these samples to suit various applications in different frequency bands simply by manipulating their weight percentage and thickness indicates that these hybrid nanocomposites could be a promising electromagnetic wave absorber. [ABSTRACT FROM AUTHOR]

We fabricated an actuator that was made from polyurethane (PU) with carbon nanotubes (CNTs) as the filler. To improve the dispersion of the CNTs, a mild hydrothermal treatment was carried out. Carboxyl and hydroxyl groups were introduced to the surface of the CNTs, and they were found to be highly dispersed in polar solvents such as dimethylformamide. To evaluate these films, we mainly focused on electrical properties, such as dielectric spectroscopy, space charge measurements, and actuator behavior. We found that the PU/CNTs film bents toward the cathode when an electric field was applied, and it reverted to its original position when the electric field was removed. Upon the inclusion of the CNTs as the filler for the polymer, the electrical properties of the films improved significantly. The highly polarized films had a high relative permittivity, and this produced a higher Maxwell pressure, which assisted the actuation. A high accumulated charge density was observed from space charge measurements in some of the films, and this explains the bending direction and the actuation mechanism. [ABSTRACT FROM AUTHOR]

Natural gas plays an important role in daily life and the petrochemical industry, but there are often large amounts of impurities which prevent the full use of methane in natural gas. Developing excellent adsorbents to purify CH4 from multi-component mixtures is crucial, but also faces great challenges. Here, by utilizing a ligand conformation preorganization strategy, we employ a flexible nonplanar hexacarboxylate ligand with C2 symmetry to successfully construct a robust microporous metal–organic framework {[Cu3(bmipia)(H2O)3]·(DMF)(CH3CN)2}n (GNU-1, bmipia = 5-[N,N-bis(5-methylisophthalic acid)amion] isophthalate) with an unprecedented topology. More importantly, the obtained GNU-1 not only exhibits good stability in acid–base and water environments, but also shows potential utility as an adsorbent for efficient separation and purification of natural gas under ambient conditions. The adsorption isotherms of GNU-1a (activated GNU-1) exhibit strong binding affinities for C2H6 and C3H8, a remarkable uptakes of C3H8 (6.64 mmol g−1) and C2H6 (4.6 mmol g−1) and an excellent selectivity of 330.1 and 17.5 for C3H8/CH4 and C2H6/CH4 mixtures, respectively, at 298 K and 1 bar. The breakthrough experiments demonstrate that the ternary CH4/C2H6/C3H8 mixtures are completely separated using a fixed-bed separator packed with GNU-1a at ambient temperature and also show great potential for recovering the C2H6 and C3H8 contents from natural gas. Finally, Grand Canonical Monte Carlo simulations are adopted to ascertain potential gas adsorption mechanisms. This work proves the feasibility of optimizing the structure and pore size of MOF materials by regulating the conformation of ligands for application in the field of light hydrocarbon adsorption/separation. [ABSTRACT FROM AUTHOR]

A nanocomposite actuator film incorporated with carbon nanotubes (CNTs) was fabricated and evaluated. The materials are polyurethane and modified CNTs as the filler. The CNTs were modified using microwave-induced polymerization modification route to improve the dispersion. The actuator performance test revealed that the films bent to the cathode side when voltage was succeeded and reverted to their original position when the voltage was removed. Moreover, the electrical properties were evaluated and the charge accumulation was observed near the anode side when voltage is applied to the films. Based on this asymmetric charge density inside the films, a model which predicts the bending direction and actuation mechanism was suggested. [ABSTRACT FROM AUTHOR]

Silver (Ag) nanoparticles fabricated by chemical reduction process were grafted onto the surface of carbon nanotubes (CNTs) to prepare hybrid nanocomposites. The Ag/CNT hybrid nanomaterials were characterized using transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The Ag/CNT hybrid nanomaterials were then loaded in paraffin wax, and pressed into toroidal shape with thickness of 1 mm to evaluate their complex permittivity and complex permeability by scattering parameters measurement method in reflection mode using vector network analyzer. The reflection loss of the samples was calculated according to the transmission line theory using their measured complex permittivity and permeability. The minimum reflection loss of the Ag/CNT hybrid nanocomposite sample with a thickness of 1 mm reached 21.9 dB (over 99 % absorption) at 12.9 GHz, and also exhibited a wide response bandwidth where the frequency bandwidth of the reflection loss of less than −10 dB (over 90 % absorption) was from 11.7 to 14.0 GHz. The Ag/CNT hybrid nanocomposite with thickness of 6 mm showed a minimum reflection loss of ~−32.1 dB (over 99.9 % absorption) at 3.0 GHz and was the best absorber when compared with the other samples of different thickness. The reflection loss shifted to lower frequency as the thickness of the samples increased. The capability to modulate the absorption band of these samples to suit various applications in different frequency bands simply by manipulating their thickness indicates that these hybrid nanocomposites could be a promising microwave absorber. [ABSTRACT FROM AUTHOR]

Abstract: In this work, wave propagation characteristics of double-layer graphene sheets (DLGSs) are investigated using nonlocal Mindlin–Reissner plate theory. The vibrational modes are divided into in-phase mode and anti-phase mode, which is a special feature of DLGSs. The wave propagation behaviors in DLGSs in the in-phase mode and anti-phase mode are different. Cutoff frequency and escape frequency are analyzed in this study. In particular, the escape frequencies with different nonlocal parameters are less than that obtained from nonlocal Timoshenko beam theory and different between the in-phase mode and anti-phase mode. This is because shear forces consider the nonlocal effects in nonlocal Mindlin–Reissner plate theory, but do not consider the nonlocal effects in nonlocal Timoshenko beam theory. Thus, the present work will provide a better representation of wave propagation in DLGSs and will have implications in their application as electromechanical oscillators. [Copyright &y& Elsevier]

Double-layer graphene sheets (DLGSs) have potential applications as nanoelectromechanical systems (NEMS) resonators due to their specific carrier spectrum of electrons. In this study, analysis of the vibration modes of NEMS resonators using simply supported circular DLGSs has been undertaken based on nonlocal thin plate theory. Considering the properties of DLGSs, the vibration mode of circular DLGSs can be divided into an in-phase mode (IPM) and an anti-phase mode (APM). The range of resonance frequencies in the IPM is much larger than in the APM because of the influence of van der Waals forces. Nonlocal effects significantly influence the resonance frequency of circular DLGSs in higher vibration modes and at lower aspect ratios. [ABSTRACT FROM AUTHOR]

Functionally graded nano-TiO2 epoxy matrix composites were successfully fabricated using a centrifugal method. In the preparation of the composite, the aggregation of nano-TiO2 occurred during curing, which had a negative effect on the composite performance. To solve this problem, we introduced a silane coupling agent to modify the surface of the nano-TiO2, thereby improving the performance and mechanical properties simultaneously. The modified nano-TiO2 (s-TiO2) had better dispersion in the epoxy resin, making it possible to produce depth gradients of the mechanical properties of functionally graded materials (FGMs). The s-TiO2 was characterized with respect to functional groups, morphology, and chemical elements using transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The results show that a silane layer was successfully coated on the surface. Also, the gradients of the mechanical and permittivity properties of the FGM indicated that by modifying the surface of the nano-filler, it is possible to fabricate nano-filler-reinforced epoxy matrix FGMs using a centrifugal method. POLYM. COMPOS., 35:557-563, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Forest fragmentation and isolation can reduce the size of available habitat and lead to lower food availability for some primate species. The persistence of nonhuman primates in fragments depends largely on their ability to adjust their diet in response environmental change. The western black crested gibbon ( Nomascus concolor) is distributed in northern Vietnam, northwestern Laos, and southwestern China, but little is known about its diet except from studies in the well-protected forests of Mt. Wuliang and Mt. Ailao, central Yunnan. We studied food abundance and diet over 2 years in a small group surviving in an isolated and disturbed forest at Bajiaohe, southern Yunnan, and drew a comparison with the population at Dazhaizi in Mt. Wuliang. We found that gibbons at Bajiaohe consumed mostly fruit, but did not eat figs, unlike most other gibbon populations. Liana fruits and mature leaves were used as alternative foods during periods of tree fruit scarcity. Our results indicate that gibbons in Bajiaohe respond to habitat fragmentation and isolation by consuming a variety of plant species, depending on those that are locally available, and increasing time spent feeding on fruits of trees and lianas rather than increasing time spent consuming leaves. Am. J. Primatol. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Functionally graded multiwalled carbon nanotube (MWCNT) reinforced epoxy matrix composites are fabricated using a centrifugal method. Aggregation of the MWCNTs during the epoxy curing process is prevented using a two-step aminosilane modification. Chemical interaction of the silane with the oxidized nanotube surface is confirmed using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Raman spectroscopy of acid-treated MWCNTs corroborates the formation of surface defects owing to the introduction of carboxyl groups. The mechanical and microwave absorption property gradients of the composites correspond with those produced via silane modification indicating potential application to microwave absorbing materials. The MWCNTs are better dispersed in the epoxy resin after the modification, making it possible for them to become efficiently graded in the epoxy matrix. We therefore show that it is possible to fabricate functionally graded nanofiller-reinforced materials using the centrifugal method by modifying the surface of the nanofiller. Functionally graded MWCNT-reinforced epoxy matrix composites are fabricated using a centrifugal method. Aggregation of the MWCNTs during the epoxy curing process is prevented using a two-step aminosilane modification. The mechanical and microwave absorption property gradients of the composites correspond with those produced via silane modification, indicating potential application to microwave absorbing materials. [ABSTRACT FROM AUTHOR]

NASICON‐type Na3VM(PO4)3 (M: transition metals) cathodes usually suffer from poor cycling stability in the voltage region of above 4 V versus Na+/Na owing to irreversible phase transition and severe structural distortion. Herein, the high entropy concept is extended to NASICONs and Na3VAl0.2Cr0.2Fe0.2In0.2Ga0.2(PO4)3 (NVMP) with high purity is obtained. The NVMP achieves a highly reversible specific capacity of 102 mAh g−1 (2.5–4.4 V vs Na+/Na) via the successive redox reaction of V3+/V4+/V5+ together with a long‐term lifespan of 5000 cycles at 20 C (a capacity retention of 86.8%). Even at an extreme temperature of −20 °C, the NVMP cathode can still provide excellent cycling performance (a capacity retention of 94.2% at 5 C after 1000 cycles). Moreover, the increased configurational entropy in the electrode renders a quite small cell volume change of 1.1%. The sodium ion storage mechanism containing solid solution‐type in the voltage range of 2.5–3.8 V and bi‐phasic in 3.8–4.4 V is revealed by ex situ XRD analysis. Pairing with a hard carbon anode, NVMP//HC cell offers a specific capacity of 81 mAh g−1 at 0.2 C based on the cathode mass. This high‐entropy engineering is expected to be widely applicable for the development of polyanionic electrode materials. [ABSTRACT FROM AUTHOR]