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With the increasingly serious plastic pollution, people's demand for the multi-functional biodegradable plastics is becoming more and more urgent. Inspired by the crosslinked shape memory polymers, the crosslinked starch films were synthesized by inducing the decomposition of benzophenone into free radical and depriving hydrogen on starch macromolecules under UV irradiation, in order to gain a high shape memory performance. The results showed that a three-dimensional crosslinking network between starch macromolecule chains was formed. Compared with the uncrosslinked starch films, the photo-crosslinked films not only had higher mechanical property (tensile strength increased by 154%), but also had better water resistance (water contact angle from 60° to 87°) due to the reduction of free hydroxyl groups. In addition, the stable covalent bonds serving as netpoints endow photo-crosslinked films with great improvement in shape memory property, with nearly 180° bending recovery. More importantly, the maximum shape memory fixity ratio (Rf) and shape memory recovery ratio (Rr) under stretch deformation were 96.5% and 99.8%, respectively. And the Rf and Rr could reach 94.6% and 79.8% even at higher strain. In all, the excellent shape memory performance and good degradability crosslinked starch films, which have great potential application in disposable heat-shrinkable packaging materials.

In order to solve the transient heat transfer problem of the laminated structure, a semianalytical method based on calculus is adopted. First, the time domain is divided into tiny time segments; the analytical solution of transient heat transfer of laminated structures in the segments is derived by using the method of separation of variables. Then, the semianalytical solution of transient heat transfer in the whole time domain is obtained by circulation. The transient heat transfer of the three-layer structure is analyzed by the semianalytical solution. Three time-varying boundary conditions (a: square wave, b: triangular wave, and c: sinusoidal wave) are applied to the surface of the laminated structure. The influence of some key parameters on the temperature field of the laminated structure is analyzed. It is found that the surface temperature of the laminated structure increases fastest when heated by square wave, and the maximum temperature can reach at 377°C, the temperature rises the most slowly when heated by the triangular wave, and the maximum temperature is 347°C. The novelty of this work is that the analytical method is used to analyze the nonlinear heat transfer problem, which is different from the general numerical method, and this method can be applied to solve the heat transfer problem of general laminated structures.

The increasing temperature of lithium‐ion batteries during charging and discharging affects its operational performance. The current studies mainly adopt simplified model, less considering the effect of the battery internal electrochemical reaction on the air cooling performance, and the air cooling structure needs to be further optimized. In order to solve the problems above, the coupled electrochemical‐thermal air cooling model was established, and the air cooling structure was optimized in terms of the relative position and height of the battery pack inlet and outlet, the distribution, and spacing of cells. The results show the better air cooling performance is achieved when the inlet and outlet are aligned on the same side. When the lateral inlet and outlet aligned on the same side, the lower outlet height is more important for improving the heat dissipation performance of the battery pack, but the worse temperature uniformity emerges. According to the cooling performance of different positions in the battery pack, a method for nonequidistant symmetrical distribution of cells is able to improve the temperature uniformity. The optimal combination of the air cooling structure with various factors is obtained.

In this article, we report a newly designed D-A-D' derivative (CNCzPTZ), which displays selective expression of chromophores. This enables CNCzPTZ with solvatochromism, rare dual-mode AIEE properties, solid-state dual-emissions with phosphorescence and distinctive mechanochromism.CNCzPTZ exhibits dual-mode AIEE properties, since the emission band abruptly shifts from 550 nm to 500 nm as the water fraction increases. In the crystalline state, CNCzPTZ demonstrated dual emission bands of 478 nm and 538 nm.CNCzPTZ shows distinctive mechanochromic property in the solid state due to the planarization.

Previously our laboratory first reported that dropping of freeze-dried monoclonal antibody (mAb) formulations could cause protein degradation and aggregation (J Pharm Sci, 2021, 1625). In this manuscript, we evaluated effects of secondary package on stability of several freeze-dried biopharmaceutical formulations during dropping. The degradation of mAb-Y during dropping with different secondary packages was determined by the sensitive particle analyzing techniques micro-flow imaging (MFI) and dynamic light scattering (DLS). Electron paramagnetic resonance (EPR) was used to detect free radicals after repeated dropping in different secondary packages. The amount of free radicals and SbVPs was correlated to the sample temperature as well as the secondary package during dropping. Our observations suggest that secondary packaging has significant effect on freeze-dried biopharmaceutical stability during dropping and therefore should be thoroughly screened and optimized to assure high product quality even for the presumed highly stable freeze-dried biopharmaceuticals.

Dibenzo-18-crown-6 (DB18C6) as a host compound was doped into polyacrylonitrile (PAN) solution. The composite nanofibers (DB18C6/PAN) were prepared by the electrospinning. The morphology, chemical structure and thermal stability of nanofibers were characterized by field emission scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA), respectively. The composite nanofibers with good morphology were obtained by controlling the weight percent of DB18C6 and electrospinning parameters. The static adsorption behavior of alkali metal ions and alkaline earth metal ions of different proportional DB18C6/PAN nanofibers were studied. DB18C6/PAN nanofibers have adsorptive selectivity about alkali metal ions: K+ > Na+ > > Cs+ > Li+. The 15wt%DB18C6/PAN nanofibers have the highest adsorption capacity. The adsorption kinetics of 15wt%DB18C6/PAN nanofibers for Na+ and K+ were accorded with the first-order equation, and the adsorption rate constants were 9.5 × 10–3 min−1 and 1.5 × 10–2 min−1, respectively. At 25 °C, the isotherm adsorption of the DB18C6/PAN nanofibers for Na+ and K+ was confirmed to the Langmuir adsorption isotherm, and the maximum adsorption quantities of 15wt%DB18C6/PAN nanofibers were 11.9 mg g−1 and 24.8 mg g−1, respectively.

In this work, cobalt glycerate (CoG@F127) nanosheets grown on the surface of graphene oxide (GO), i.e. CoG@F127/GO, have been synthesized with the assistance of nonionic surfactant Pluronic F127 via a hydrothermal method. After calcination, CoG@F127/GO is transformed into one derivative, Co nanoparticles coated with a trace amount of carbon (Co-C) on GO (Co-C/GO). The Co nanoparticles consist of an atypical core–shell structure, in which the core and the shell are both Co. Co-C anchored on GO can avoid the nanoparticles aggregation and expose more active sites for hydrogen evolution reaction (HER) to significantly improve the catalyst activity of HER. CoG@F127/GO is phosphatized to form the other derivate, cobalt pyrophosphate coated with a small amount of carbon (Co2P2O7-C) on GO (Co2P2O7-C/GO). Co2P2O7-C/GO composite owns a large electrochemical active surface area (ECSA) and fast rate towards oxygen evolution reaction (OER). Furthermore, the two derivatives of CoG@F127/GO, i.e. Co-C/GO and Co2P2O7-C/GO as twin flowers, are assembled into an overall water splitting electrolytic cell with a cell voltage of 1.56 V to deliver a current density of 10 mA cm−2.

The effect of carbazole isomers (benzoindole, Bd) on phosphorescence has attracted much research interest recently since it was discovered last year. However, the phosphorescence mechanism of carbazole/benzoindole is still unclear and urgently needs to be addressed. Where is the true crystallization phosphorescence in pure carbazole-based systems? What can we do to make full use of the isomer effect? In order to distinguish the crystallization phosphorescence from the isomer induced phosphorescence, we introduced halogens to the PhCz skeleton to gain intense crystallization phosphorescence, and synthesized the target molecules with carbazole from different sources. The target molecule synthesized from the purchased carbazole (CNCZBr-Cm) depicts a bright yellow afterglow (550 nm) with ultralong lifetime at room temperature, whereas the same molecule synthesized from synthesized carbazole (CNCZBr-Lab) only shows bright green phosphorescence at 500 nm and its phosphorescence is short-lived, which is verified to be the true crystallization phosphorescence. HPLC-HRMS spectroscopy showed the isomer in CNCZBr-Cm and determined its content to be as low as 0.024%. The carbazole isomers help to form a charge separated state, which reduces the radiation rate of phosphorescence, leading to an ultralong afterglow. We propose a more comprehensive phosphorescence mechanism for the carbazole&benzoindole system, including molecular phosphorescence (453 nm) and carbazole crystallization/dimer phosphorescence (500 nm), and carbazole&benzoindole heterojunction phosphorescence (550 nm). Furthermore, by adjusting the ratio of isomers, a series of doped systems with different phosphorescence lifetimes and intensities can be obtained. The proposed mechanism inspired us to obtain a simple but universal strategy for quantitatively adjusting the lifetime of carbazole-based phosphors and the obtained materials can be put into practical applications in the advanced encryption field.

Stimulus-responsive purely organic room-temperature phosphorescence materials have been drawing massive attention due to their wide applications. Pyridine rings are introduced to supply π orbitals and cyanogroups are incorporated to boost the ISC efficiency by promoting the spin-forbidden transition. These groups are anticipated to enable the target molecule with multi-responsiveness because of the protonation of pyridine and their good crystallinity, which are able to regulate the acid-responsiveness and force-responsiveness, respectively. Based on the above design concept, four new D–A–A′ type molecules using carbazole as the donor and the pyridine ring and cyanogroup as acceptors were designed and synthesized. The D–A–A′ structure bestows these isomers with an evident intramolecular charge transfer (ICT) feature, particularly for 2-CNPyCZ and 3-CNPyCZ. All the isomers show intense long-lived phosphorescence with a lifetime over 500 ms. Particularly, 4-CNPyCZ has a high phosphorescence quantum yield of 27.1% owing to the strong intermolecular interactions that stabilize the excitons. Interestingly, four isomers could retain their long-lived afterglow even after being heavily ground and the afterglow shows well resistance to external forces due to high crystallinity. 4-CNPyCZ manifests unique mechanochromism owing to the fluorescence shift and intensity change of phosphorescence. Moreover, the four isomers demonstrate distinctive acid-responsiveness and give out colorful emissions because the electron cloud dispersion of the nitrogen atom in the pyridine ring varied when altering the position of the cyanogroup. To the best of our knowledge, this is a limited work on room temperature phosphorescence about systematically regulating the responsiveness to external stimuli and proposing an effective molecular design strategy.

Background: In the present situation where there is a water shortage globally, nanoparticles can play a vital role in treating wastewater to make it usable for several processes. Industrial wastewater contains numerous heavy metals and associated wastes that enter our food chain by one means or other. This article provides a review of applications of nanoparticles in wastewater treatment and highlights the significance of photocatalytic nanoparticles in general. Methods: Online journals and books related to wastewater treatment using nanoparticles are reviewed to compile their essentials findings. General mechanisms, applications, limitations, and comparison of photocatalytic nanoparticles are reviewed as well. Results: A study of photocatalytic nanoparticles shows that TiO2 and ZnO nanoparticles have excellent photocatalytic capabilities as compared to other nanoparticles due to their bandgap properties; however, the usage of these nanoparticles is limited since there is higher recombination rate of electrons and holes in photocatalysis. Further, individual limitations also exist as TiO2 is inoperable in the visible light region. So, their heterostructures with other nanoparticles have been developed to overcome their limitations. Other nanoparticles, like noble metals, and those like CuO, CeO2, SnO2 have potential in carrying out photocatalytic degradation of contaminants of wastewaters. Conclusion: Several contaminants can be eliminated from wastewater bodies using photocatalytic nanoparticles. The efficiency of photocatalytic nanoparticles can be enhanced by coupling them with suitable species. Research in this area can prevent the water shortage of upcoming years.

The objective of this paper is to experimentally investigate the cavitation patterns and corresponding hydrodynamics of the hydrofoil with leading edge roughness. The aims are to (1) understand the effect of the leading edge roughness on the hydrodynamic performance, and (2) have a good knowledge of the interaction between the leading edge roughness and the cavitation patterns. Experimental results are indicated for the NACA 66 hydrofoils with and without leading edge roughness at different incidence angles for sub and cavitation conditions. The experiments are conducted in the EPFL high-speed cavitation tunnel (Avellan 2015). The results showed that the leading edge roughness has a significant effect on the hydrodynamic performance at the sub cavitation, suppressing the formation of the incipient cavitation. The lift coefficient of the hydrofoil without leading edge roughness is larger than that of the hydrofoil with leading edge roughness, while for the drag coefficients, the results are contrary for the lift coefficient, and the maximum lift-to-drag ratio angle is delayed for the hydrofoil with leading edge roughness. The leading edge roughness modified the local pressure distribution at the leading edge region, which in turn significantly increased the minimum pressure coefficient, hence the incipient cavitation number of the hydrofoil with leading edge roughness. The formation and evolution of the transient cavity for the cloud cavitation is little affected by the leading edge roughness.

High cost of Pt counter electrode restricts large-scale application of dye-sensitized solar cells (DSSCs). Therefore, it is of great practical significance to develop new counter electrode materials with low cost, good stability and high catalytic activity to replace Pt counter electrode. In this paper, bimetallic sulfides (Co8FeS8/N-C and (Co0.75Ni0.25)9S8/N-C anchored on graphene oxide (GO) were synthesized using ZIF-67 as precursor by subsequent sulfuration and cation exchange method. The electrochemical results showed that the composite of Co8FeS8/N-C/GO and (Co0.75Ni0.25)9S8/N-C/GO displayed improved electrocatalytic performance for I−/I3− redox reaction owing to the introduction of GO and the synergic catalytic effect between bimetallic sulfides and GO. When Co8FeS8/N-C/GO and (Co0.75Ni0.25)9S8/N-C/GO were applied as low-cost counter electrode for the DSSCs, they achieved high photo-electric conversion efficiency of 8.74% and 8.98%, respectively. This notion and expedient strategy of combination could be widened to construct other composite of bimetallic sulfides with GO, which might exhibit the desired electrocatalytic performance and potential applications.

SnO2 has been widely studied in lithium-ion batteries (LIBs) because of its high theoretical specific capacity and reversible alloying reaction. Herein, we reported a novel strategy of confinement growth to implant nano-sized SnO2 crystals into N-doped hollow mesoporous carbon spheres (NHMCS) to form SnO2@NHMCS composite with unique nanoscale voids. The nanocrystals (~ 5 nm) decrease the required activation energy for redox reactions, and the carbon shell of NHMCS improves the conductivity and structural stability. It is worth noting that this method can effectively control the filling degree of ultrasmall nanocrystals in NHMCS and adjust the nanosize of voids between nanocrystals and NHMCS. When SnO2@NHMCS is evaluated as an anode material for LIBs, it is proved to exhibit high reversible capacity and stable cycling performance, which is attributted to the appropriate content of active components and the ample buffer space for conversion reaction of SnO2 and alloying reaction of Sn. It also shows excellent electrochemical property as anode material for sodium-ion batteries.

The recycling of heavy metals from solid wastes and transforming these metals into useful materials, such as metal oxides, nanocomposites, and metal–organic frameworks (MOFs), are beneficial for both sustainable development and environmental protection. MOFs are promising for adsorptive desulfurization, owing to their extremely high surface areas and tunable structures. In this paper, for the first time, MIL-53(Cr) was successfully fabricated from electroplating sludge (EPS) as a metal source through a facile hydrothermal method with and without HF. Our synthetic method is novel, green, scalable, and time-efficient. The obtained MIL-53(Cr) was employed as an adsorbent for adsorptive dibenzothiophene removal from liquid fuel. MIL-53(Cr) with HF exhibits a higher desulfurization capacity (40.11 mg g–1) than that of MIL-53(Cr) without HF (32.80 mg g–1). The improved adsorption performance of MIL-53(Cr) with HF is attributed to adding a small amount of HF, which produces highly crystalline and relativity pure MIL-53(Cr) microrods with a high surface area and porosity, and is due to a robust metal–sulfur interaction. Furthermore, the regenerated adsorbent can retain 94% of its initial sulfur adsorption capability even after 5 cycles, implying that MIL-53(Cr) prepared from Cr-EPS is an efficient adsorbent for fuel desulfurization. This study provides new insight for the production of high-value-added MOF materials from solid wastes following the principle of “resource reuse”.

Based on hydrothermal synthesis and solid-phase thermal reaction, LiNi0.8Co0.15Al0.05O2 hollow nanospheres (LNCA HNSs) were synthesized by using SiO2 hollow nanospheres as hard template. Firstly, the SiO2 HNSs were prepared. Then, (Ni0.8Co0.15Al0.05)CO3 nanosheets grew on the surface of SiO2 HNSs to form SiO2@(Ni0.8Co0.15Al0.05)CO3 hollow nanospheres with double shells by hydrothermal method. Finally, the above precursors and lithium source were calcined at high temperature, and then SiO2 template was etched to obtain hollow LNCA HNSs. The characterization results showed that the LNCA HNSs are hollow spheres with a diameter of about 1.8 μm. The shell thickness of LNCA HNSs is about 300 nm. Compared with LNCA nanoparticles and LNCA microparticles, LNCA HNSs showed excellent stability, high capacity, and good rate performance as cathode materials for lithium ion batteries. The LNCA HNSs exhibited a reversible capacity of 202.4 mA h g−1 at 0.1 C and good stability of 179.1 mA h g−1 at 1 C after 80 cycles.

Understanding the nanoparticle deposition process is important for predicting the transport and fate of nanoparticles in natural and engineered aquatic environments. Traditional methods for deposit...

Based on the confined growth strategy and hydrogen thermal reduction, uniform yolk-shell structured Sn@NHMCSs were designed with metal Sn as the core and mesoporous carbon as the shell. The void between the Sn yolk and carbon shell provides enough buffer space for the expansion of the alloying reaction of Sn, which greatly improves the poor cycling stability of Sn as an anode material in lithium ion batteries. In addition, we observed that tiny particles were still encapsulated in the hollow carbon sphere cavity after the alloying/dealloying reaction.

Understanding the contact behaviour of 2D materials in nanoscale is of great importance for their applications. In the present work, molecular dynamics simulation is employed to study the frictional behaviour of the AA′ and AB stacked multilayer silicene for up to 4 layers placed on the weakly adhesive amorphous SiO2 substrate with a sliding AFM tip. During the sliding process, the AFM cantilever represented by virtual atoms moves with the velocity of 2 m s−1 along the zigzag direction under a load of 2 nN at 300 K. The stick-slip frictional behaviour shows high sensitivity to the number of layers. As the thickness increases, the friction force first increases from the monolayer to bilayer and then decreases from the bilayer to 4-layer, which shows an exotic tendency for the first time among all the reported lamellar materials to date where the friction usually decreases monotonically with thickness. For all the investigated thicknesses, the friction on AA′-stacked silicene is slightly larger than the AB stacked counterpart, and the difference diminishes with increasing thickness. The frictional behaviour of AA′ bilayer presents the highest peak force with evolving weakening phenomenon induced by a phase transition to the planar structure. Herein, we analyze the frictional force distribution on the tip with kurtosis and skewness as measurement parameters for the commensurability and rigidity components, respectively. The contact area between silicene and the diamond tip is compared for different silicene morphologies. The result shows an affinity between friction and rigidity of multilayer silicene, which is closely related to the interlayer covalent bonds and limited shear between sublayers.

The numerical prediction of effective diffusivity in hardened cement paste has been a hot point in the past few decades. However, the shape of cement powder is normally over-simplified as sphere in most models, which may influence the accuracy of prediction. To assess this effect of the shaped simplification on the prediction of effective diffusivity in cement paste, a microstructure-based model considering irregular-shaped cement powders that are close to the real one, and spherical cement powder respectively, is presented to simulate the hydrating cement pastes between aggregates (interfacial transition zone and bulk cement paste) and predict their effective diffusivities. The results indicate that the effect of the shape of cement powder on the distributions of capillary pore and unhydrated cement is weak. Furthermore, compared to the irregular-shaped cement powder, the diffusivity in cement paste simulated using spherical cement powders is overestimated by 0–40%. It is ascribed to three discrepancies, i.e., the shape of initial cement powder, the formation of capillary pore structure, and the morphology of C-S-H. However, the predicting error using spherical cement powder is still acceptable by contrast to the large difference of diffusivity in hardened cement paste with cement hydration, i.e., normally two orders of magnitude difference between early and later curing ages.

In this article, we report a simple tetra-arylethene-based fluorescent switch TPS═C4 modified with a flexible alkyl chain by the Schiff base structure. The incorporation of C═N retains the excellent photochromic property of tetra-arylethene and endows TPS═C4 with new multiresponsiveness of mechanochromism and acidichromism and multicolor changes. TPS═C4 shows remarkable mechanochromism from a deep blue emission at 420 nm to bright blue with a new shoulder band at 450 nm, which arises from the force-induced phase transition from the crystal state to an amorphous form. Both the original crystalline powder and the ground amorphous sample exhibit interesting acidichromism, and their emission colors turn yellow (530 nm), due to the protonation of C═N. More interestingly, TPS═C4 displays fascinating photochromism in multiple states, especially in the single-crystal state. The flexible alkyl chain offers enough free space for molecular motion and facilitates single-crystal photochromism. Due to the multiresponsiveness and multicolor switch, TPS═C4 can be satisfactorily used for the multidimensional anticounterfeiting application. To the best of our knowledge, TPS═C4 is a rare multifunctional molecule with a simple structure but featuring multiresponsiveness and multicolor switch.

To preserve the quality of frozen food products, the main goal of suitable thawing is to cause the least amount of damage with the shortest possible thawing time. A radiofrequency (RF) system has potential for use in achieving these goals for industrial thawing operations. This study investigated the characteristics of RF thawing, and sought to determine the optimal conditions for RF thawing by clarifying the temperature distributions in blocks of frozen minced fish. The dielectric properties (DPs) of frozen minced fish and the penetration depths (dp) of thawing were measured under differing methods and conditions. The temperatures measured by the probes were plotted in Surfer and verified by COMSOL simulation. A sharp increase in DPs (e′ and e″) was observed at a frequency of 27.12 MHz (from −3 °C to 0 °C), and a striking dp was found from −15 °C to −5 °C, Electromagnetic waves at this frequency could penetrate our samples easily, and the uniformity of heating was improved at both ranges of temperature. For the size of frozen minced fish blocks that are commonly used in the industry (25 × 15 × 5 cm), the most suitable electrode gap for thawing was found to be 16 cm. Unlike in the results obtained with other thawing methods, the cooked gel properties after RF thawing were unaffected, which proved that the RF system is optimal for use in industrial production.

The development of optical imaging techniques has led to significant advancements in single-nanoparticle tracking and analysis, but these techniques are incapable of label-free selective nanoparticle recognition. A label-free plasmonic imaging technology that is able to identify different kinds of nanoparticles in water is now presented. It quantifies the plasmonic interferometric scattering patterns of nanoparticles and establishes relationships among the refractive index, particle size, and pattern both numerically and experimentally. Using this approach, metallic and metallic oxide particles with different radii were distinguished without any calibration. The ability to optically identify and size different kinds of nanoparticles can provide a promising platform for investigating nanoparticles in complex environments to facilitate nanoscience studies, such as single-nanoparticle catalysis and nanoparticle-based drug delivery.

The influences of laser focusing geometry on laser-induced plasma and laser-induced breakdown spectroscopy (LIBS) in bulk water are investigated by using fast imaging and spectroscopic techniques. Comparisons between different focusing geometries (spherical aberrations and focusing angles) are performed in terms of breakdown thresholds, plasma morphologies, emission distributions, pulse-to-pulse plasma fluctuations, and the corresponding LIBS signals. It is shown that spherical aberrations lead to an increase in the threshold energy of breakdown, to a formation of multiple elongated plasmas with weak emissions, and to a decrease in the signal intensity as well as LIBS stability. With aberration minimized focusing, larger focusing angles produce a lower breakdown threshold, a compact plasma with stronger emissions, and a higher signal intensity as well as higher LIBS stability. In particular, we demonstrate that with the minimized spherical aberrations and large focusing angles, the intensities of plasma emission continue to increase at higher laser energies and no clear saturation is observed. The present results suggest that a relatively large focusing angle should be applied for LIBS measurement in bulk water, and the spherical aberrations should be eliminated.

The catalytic properties of ultrafine metal nanoparticles (NPs) are usually limited by their dispersion of NPs; support is thus needed for ultrafine metal NPs. However, single-dimensional supports ...

PVDF pyroelectric sensor has been widely applied in many fields, such as intruder alarm. Nowadays, this sensor shows a potential for ultrasonic power measurement. However, the transformation mechanism between the acoustic and pyroelectric signals has not been particularly studied until now. In this paper, a physical model was introduced for theoretical study of the mechanism of energy transformations. In addition, a simulation program based on finite-element analysis method was built up for analyzing the ultrasound propagation characteristics and the temperature rise on the PVDF, as well it predicted the waveform and amplitude of the generated pyroelectric signal. Besides that, a PVDF pyroelectric sensor was fabricated and used for acoustic power measurement experiment. Finally, the experiment and simulation results were compared, confirming that the physical model is suitable for pyroelectric sensor characteristics analysis. It can also provide useful suggestions for the design and fabrication of PVDF pyroelectric sensors with high sensitivity.

The interaction between cellulose and hemicelluloses is of fundamental importance for understanding the molecular architecture of plant cell walls. Adsorption of xyloglucan (XG) onto regenerated cellulose (RC), sulfated cellulose nanocrystal (s-CNC), and desulfated cellulose nanocrystal (d-CNC) films was studied by quartz crystal microbalance with dissipation monitoring, surface plasmon resonance, and atomic force microscopy. The amount of XG adsorbed onto different cellulose substrates increased in the order RC < s-CNC < d-CNC. The adsorption of XG onto RC films was independent of film thickness (d), whereas XG adsorption was weakly dependent on d for s-CNC films and strongly dependent on d for d-CNC films. However, approximately the same amount of XG adsorbed onto “monolayer-thin” films of RC, s-CNC, and d-CNC. These results suggest that the morphology and surface charge of the cellulose substrate played a limited role in XG adsorption and highlight the importance of film thickness of cellulose nanocrystalline films to XG adsorption.

The 1-(3-aminopropyl)-3-methylimidazolium bromide ([APMIm][Br]) functionalized graphene oxide ([APMIm][Br]-GO) and 1-methylimidazolium trifluoromethanesulfonate ([MIm][TfO]) are prepared and used as fillers and proton carrier in the preparation of high temperature hybrid proton exchange membranes (PEMs), respectively. The PEMs are obtained via photo-initiated polymerization of a mixture containing polymerizable oil (styrene/acrylonitrile and divinylbenzene), protic ionic liquid (PIL, [MIm][TfO]), and different content of [APMIm][Br]-GO. The resultant membranes show good thermal stability and excellent mechanical properties. Incorporation of proper amount of [APMIm][Br]-GO significantly increases the proton conductivity of the hybrid membranes, and the membranes with 1.0 wt% [APMIm][Br]-GO shows the highest conductivity (up to 1.48 × 10−2 S cm−1 at 160 °C). Compared with the plain membrane without [APMIm][Br]-GO, the hybrid membranes with [APMIm][Br]-GO show much better PIL retention ability. These properties make this type of PIL-based hybrid membranes suitable for the application of high-temperature proton exchange membrane fuel cells (PEMFCs).

Liquid protein-based biopharmaceutical formulations have been reported to form aggregation and protein sub-visible particles (SbVPs) during dropping (Randolph et al., J Pharm Sci 2015, 104, 602). However, effects of secondary package on liquid biopharmaceutical formulation stability during dropping are overlooked and have not been reported so far. This study reports the first real-world evaluation on effects of secondary package on liquid biopharmaceutical formulation stability during dropping, using two monoclonal antibodies (mAb-1 and mAb-2) and one fusion protein (FP-1) as model biopharmaceuticals. The potential protective effects of secondary package and formulation composition on liquid biopharmaceutical formulations during dropping were evaluated with micro-flow imaging (MFI) and dynamic light scattering (DLS). The dropping-induced degradation could be detected with the two sensitive particle analyzing techniques MFI and DLS. Formulation compositions have dramatic impact on biopharmaceutical stability during dropping. Surprisingly, unlike the primary packages that have been reported to impact liquid biopharmaceutical stability, the secondary packaging system as described in our current preliminary design has little or no protective effect during dropping. Our study is the first real-world data showing that the secondary package system has little to no effect on the liquid biopharmaceutical formulation quality during dropping. On the contrary, the stability of liquid biopharmaceutical formulations during dropping is more relevant to formulation compositions and primary packages.

In order to comprehensively optimize the axial force and hydraulic performance of the multistage pump, considering that there are relatively more secondary impeller stages and the blade profile has a greater impact on the axial force and hydraulic performance, Plackett–Burman test design method in this paper is adopted to conduct significance analysis and screening of the secondary impeller parameters. Based on the response surface methodology, a central composite test is designed for three control variables with strong sensitivity. The multiple regression model between the parameters of the secondary impeller and the hydraulic performance and axial force of the multistage pump is established. The optimal parameter combination which takes the performance and axial force into account is obtained. The accuracy of the optimization results is verified through tests. The results show that the blade exit angle, outlet diameter and blade wrap angle of the secondary impeller have the most significant influence on the axial force and hydraulic performance of the multistage pump. The results of variance analysis and coefficient test show that the regression model is highly significant and can reflect the objective relationship between the control parameters of the secondary impeller shape and the response objectives. A larger outlet diameter and blade wrap angle of the secondary impeller can improve the head of the multistage pump. A larger blade wrap angle and a smaller blade exit angle of the secondary impeller can reduce the axial force of the multistage pump. By solving the multiple regression equation, it is found that when the outlet diameter of the secondary impeller is 292 mm, the blade exit angle is 22°, and the blade wrap angle is 150°, the axial force of the multistage pump is the lowest and the hydraulic performance is slightly improved. It is verified by experiments that the head and efficiency of the optimized multistage pump increase by 0.95% and 1.71%, respectively, the temperature of the front and rear bearings decreases by 16.49% and 16.17%, respectively, and the vibration speed of the multistage pump along three directions is significantly reduced.

According to the phase gradient transfer function (PGTF) derived from the phase space theory, the phase recovery algorithm based on the transport of intensity equation (TIE) has the problem that the high-frequency phase is underestimated due to the coherence effect of the limited aperture system under partially coherent illumination. Therefore, based on the theory of PGTF and phase transfer function (PTF), a phase reconstruction algorithm named high-resolution synthetic spectrum (HSS) method combining the TIE and the PTF-based deconvolution is proposed. This technique broadens the application range and provides high contrast, high accuracy, and highresolution quantitative phase results with high robustness. The performances of this technology are demonstrated by simulation and experiments, showing efficient for phase retrieval in the near-Fresnel region. Such a highresolution method can offer a flexible and cost-effective alternative for biomedical research and cell analysis, providing new avenues to design powerful computational imaging systems

We present a miniaturized microscopic imaging system to achieve multi-contrast label-free imaging. In our imaging system, a highly integrated optical system using a miniaturization lens with fixed focal length replaces the complex optical path of traditional microscope systems, significantly reducing the size of the microscope to 14*16.5*20 cm3 . A programmable full-color light emitting diode (LED), which is controlled by independently designed operating software, is used to illuminate the sample in different illumination patterns. In addition, we developed a QT-based operating software to implement the synchronous control of the hardware system to achieve various label-free imaging approaches, including bright field, dark field, rainbow dark field, Rheinberg, differential phase contrast, and quantitative phase imaging. All the microscopic imaging approaches and system parameters can be controlled by the software without any hardware modification. In addition, some functions of the cell analysis are also added to our system, which can realize cell counter, 3D information measurement. We demonstrated our miniaturized system and its imaging results through experiments, which showed that our system is simple and fast to operate, providing more visual imaging results and high-resolution 3D information for samples. The experiment on living cell demonstrated that our miniaturized system can be built into an incubator for imaging and analysis of living cells in an environment suitable for cell growth.

In this paper, a holographic lensless quantitative phase imaging (QPI) microscope is presented, which is composed of a CMOS detector image sensor with a programmable color LED matrix, without any lens and mechanical displacement device. Such a miniaturized system can provide a field-portable cost-effective platform for highthroughput quantification of multiple samples. Coordinating the self-developed software operating system, the bright-field imaging, the quantitative phase imaging as well as cell counting, profile analysis, three-dimensional (3D) imaging and differential interference contrast (DIC) imaging can be realized. With its high-resolution based computational microscopy interface, this system can be also adaptively used for telemedicine applications and point-of-care testing (POCT) in resource-limited environments.

Printed wiring boards (PWB) are widely regarded as supporting carriers for electronic circuit products. Compared with traditional manufacturing processes, 3D printing technology is more suitable for manufacturing circuit boards of various complex shapes. At present, 3D PWB products and experimental prototypes have been successfully developed by companies and scientific research institutions. However, there is a lack of research on the failure mechanism and reliability of 3D PWB, which is an important core issue for 3D PWB engineering applications. This paper studies the debonding mechanism between the 3D PWB wire and the substrate interface, and the physical and chemical processes of debonding failure and its influencing factors are analyzed. In this paper, a 3D printer based on the principle of fused deposition modeling (FDM) printing is established. At different curing temperatures (including 100 °C, 150 °C, 200 °C, 250 °C, 300 °C), the conductive silver paste was printed on the FR-4 substrate. The mechanical properties of the printed wire such as the elastic modulus, adhesive strength in the peeling direction and shearing direction were tested. Using a scanning electron microscope (SME) to further analyze the cross-section, the results show that under different curing temperature conditions, the performance of the printed wire varies with the pore size between the silver microparticles. According to the experimental results, suggestions for improvement of process design and process control of 3D PWB are proposed. The above research can improve the performance and reliability of 3D PWB and promote the base of 3D PWB engineering application.

Artificial light-harvesting systems have attracted great interest in biological photosynthesis and photo-voltaic devices areas due to their unique structures, easy purification, low-cost, and convenient processing abilities. Here, two dendritic molecules based on triphenylamine and naphthalimide have been designed and synthesized, their structures were confirmed by 1 H NMR, ESI-MS, and high resolution mass spectrometry. In these molecules, triphenylamine units perform as the electron donor moiety, and naphthalimide units perform as the electron acceptor. The obvious quenched fluorescence intensity and considerably shortened lifetime of the dendritic molecules combined with the molecular frontier orbital energy levels proved that the dendritic molecules not only are good candidates as hole-transporting materials but also are two excellent photo-induced electron transfer materials. Therefore, it is believed that these dendritic molecules have potential application value in photo-voltaic devices.

High water content is hard to be achieved in conductive hydrogels because a mass of conductive constituent is needed to form an internal conductive pathway. Here, we developed anisotropic electrically conductive hydrogels with high water content based on bacterial cellulose (BC). Polystyrene sulfonate (PSS) was grafted to the acryloyl chloride-modified BC to provide a template for the subsequent synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT). The BC

Polyacrylonitrile fiber was successfully modified with triazine-based dendrimer via grafting method as a promising adsorbent for removal of mercury species from aqueous media. The prepared adsorbent was characterized by elemental analysis, scanning electron microscope, Fourier transform infrared spectroscopy, porous structure analysis and X-ray photoelectron spectroscopy, providing the evidence of successful fabrication. The adsorption conditions were found via varying pH, dosage, coexisting substances, contact time, temperature and concentration. Adsorption performance, described better by the pseudo-second-order kinetics with intraparticle diffusion as rate controlling step and Langmuir isotherm model, indicated a chemisorption process with the maximum Langmuir adsorption amount of 227.64 mg g−1 for mercury ions. Thermodynamically, adsorption of mercury ions was spontaneous and endothermic. Desorption and regeneration experiments demonstrated that it could be reused in five successive adsorption cycles without significant loss of its original performance. Experimental data and density functional theory calculation disclosed the coordination geometries and chelating mechanism between the adsorbent and mercury ions. The proposed study would provide a new prospect for the purification of mercury in aqueous system by functionalizing commercial polyacrylonitrile fiber with dendrimers.

Mechanically adaptive hydrogels can change their mechanical characteristics in response to external stimuli and have potential applications in biomechanical fields. To eliminate the undesired swelling/shrinkage in the responding process, poly(acrylic acid) (PAA) was grafted to acryloyl chloride (AC)-modified bacterial cellulose (BC) by free-radical polymerization. The obtained BC-g-PAA composite hydrogels showed adjustable stiffness in compression, remained soft at pH lower than 6 (compression strain over 49% at a stress of 0.1 MPa), and stiffened when pH reached 7 (compression strain lower than 27% at a stress of 0.1 MPa), while the volume change ratio was consistently lower than 15%. Based on this, the hydrogels showed interesting squat actuation to lift a weight. The BC composite hydrogels exhibited dual pH-responsiveness after grafting PAA with poly[2-(dimethylamino)ethyl methacrylate], confirming the general availability of this strategy in fabricating volumetrically stable and mechanically adaptive hydrogels. The surrounding solution-independent softening of BC-g-PAA hydrogels was observed in 8 min under UV irradiation via a photo-triggered pH jump reaction. By virtue of the selective UV irradiation, spatiotemporally controllable softening with actuation in BC-g-PAA hydrogels was realized. The developed pH-responsive mechanically adaptive BC composite hydrogels with high dimensional stability and UV-activated spatiotemporal squat actuating capability are expected to provide more options in developing novel bioimplants and smart structures.

Normal-strength concrete is widely used in construction sites considering the cost, technology, and structural safety. The ecological upgrade of such materials is more meaningful for the sustainable development in a greener way. To this end, the feasibility of ecological upgrade of normal-strength mortars (NSM) by using high volume of ground granulated blast furnace slag (GGBS) (70%–90%) was evaluated in this paper. Comprehensive experiments were conducted to investigate the influences of experimental variables such as content of cement, curing temperature, and mass ratio of water to binder (w/b) on the fresh properties, compressive strength, hydration products, microstructure, and pore structure of NSM. Ecoefficiency evaluation was conducted based on the energy requirement for the whole production of cement and GGBS. Experimental results showed that ecological upgrade of NSM was viable and feasible. When substituting 70% to 90% cement by GGBS, the energy requirement of 1 t binder can be accordingly saved by 67% to 86%, and the performance energy can be reduced from 25.4 (kWh/t)/MPa to 6 to 8 (kWh/t)/MPa. With proper contents of GGBS (70% or 75%), the 28 d compressive strengths were acceptable with reductions less than 10%. Evaluated curing temperatures and decreased w/b were viable methods to promote the early-age compressive strength of NSM incorporating high volume of GGBS. For instance, raising the curing temperature to 40°C can help achieve higher early-age compressive strength than that of the control group. In addition, the pore sizes within ZII (

In this study, we obtained dodecagonal monolayer silicene with three-fold and four-fold coordination by melt quenching via molecular dynamics (MD) simulations. Stretching simulation of the pre-strained dodecagonal silicene showed lower critical stress than the honeycomb silicene and resulted in an increase in six-fold rings during the plastic deformation since the four-coordinated atom sites are less mechanically favoured than the three-coordinated sites. The friction behaviours with an AFM tip sliding on the dodecagonal and honeycomb surfaces under different loads and tip sizes were simulated and compared. For all the investigated cases, the dodecagonal surface always showed a lower mean friction force than the honeycomb surface. The lower friction of the quasicrystal was observed, and the mechanism was illuminated successfully for the first time by MD simulations. The reduced friction of dodecagonal silicene can be explained by the morphology of the one-dimensional potential energy surface (PES). The 1D PES of dodecagonal silicene has longer potential corrugation lengths than honeycomb silicene, which induce mild motion of the tip in the stick process and lower friction force. Considering the close density of the employed dodecagonal and honeycomb structure, the longer potential corrugation length is a consequence of the quasiperiodic morphology rather than the interspace between atoms. Besides, with a larger tip size, the 1D PES on the dodecagonal surface has a flatter area, which contributes further to the reduced friction force on the dodecagonal surface.

Development of the surface morphology and shape of crystalline nanostructures governs the functionality of various materials, ranging from phonon transport to biocompatibility. However, the kinetic pathways, following which such development occurs, have been largely unexplored due to the lack of real-space imaging at single particle resolution. Here, we use colloidal nanoparticles assembling into supracrystals as a model system, and pinpoint the key role of surface fluctuation in shaping supracrystals. Utilizing liquid-phase transmission electron microscopy, we map the spatiotemporal surface profiles of supracrystals, which follow a capillary wave theory. Based on this theory, we measure otherwise elusive interfacial properties such as interfacial stiffness and mobility, the former of which demonstrates a remarkable dependence on the exposed facet of the supracrystal. The facet of lower surface energy is favored, consistent with the Wulff construction rule. Our imaging–analysis framework can be applicable to other phenomena, such as electrodeposition, nucleation, and membrane deformation., Interfacial fluctuations at the nanoscale, such as shape evolution of a growing crystal, are prohibitively difficult to study experimentally. Here, the authors are able to map the kinetic and thermodynamic parameters involved in shaping of nanoparticle supracrystals by directly imaging the fluctuating crystal surface by liquid-phase TEM, and analyzing it in the context of capillary wave theory.

Positively charged surface-treated nanoparticle (S-AK) and anionic-nonionic surfactant sodium fatty alcohol polyoxyethylene ether sulfate (AES) mixture has been used to obtain natural gas foams. It was found that synergy occurs between S-AK and AES in generating stable natural gas foams due to the foam stability of the S-AK/AES mixture being better than that of either single component. It is important to control the contents of two species since there are optimum concentrations for S-AK and AES on stabilizing Natural gas foams. High salinity (≥50,000 mg L−1) is conducive to the stability of S-AK/AES natural gas foams at high temperature (50 °C). In addition to the electrostatic interaction, EO groups significantly promote the attraction between S-AK and AES. The stability of S-AK/AES natural gas foams may relate to two aspects: one is that AES-adsorbed nanoparticles migrate to the gas/liquid interface and enhance the interfacial dilatational elasticity, and the other is that a rigid skeleton structure forms in the natural gas foam films by the flocs consisting of S-AK and AES. Natural gas foams are most stable when the monolayer adsorption of AES molecules on the S-AK surface occurs in the dispersion.

Differential phase contrast microscopy (DPC) provides high-resolution quantitative phase distribution of thin transparent samples under multi-axis asymmetric illuminations. Typically, illumination in DPC microscopic systems is designed with 2-axis half-circle amplitude patterns, which, however, reduce the temporal resolution of DPC, precluding observation of high-speed phenomenon. Efforts have been made to achieve video-rate DPC by using tri-mode illumination or adding multi-colored filter. However, the frequency responses of the PTFs has not been improved, leading to poor phase contrast and signal-to-noise ratio (SNR) for phase reconstruction. We present a video-rate isotropic quantitative phase imaging (QPI) method based on color-multiplexed differential phase contrast (DPC). In our method, the illumination source is modulated by an LCD into an annular color-multiplexed pattern matching the numerical aperture of the objective precisely to maximize the frequency response for both low and high frequencies (from 0 to 2NAobj). In addition, we propose an alternating illumination scheme to provide a perfectly circularly symmetrical phase transfer function (PTF), achieving isotropic imaging resolution and signal-to-noise ratio (SNR). A color camera records the light transmitted through the specimen, and three monochromatic intensity images at each color channel are then separated and utilized to recover the phase of the specimen. We present the derivation, implementation, simulation and experimental results demonstrating that our method accomplishes high resolution, noise-robustness and reconstruction accuracy at camera-limited frame rates.

Quantitative phase imaging (QPI), which provides unique imaging capabilities for optical thickness variation of living cells and tissues without the need for specific staining or exogenous contrast agents (e.g., dyes or fluorophores), has emerged as an invaluable optical tool for biomedical research. Differential phase contrast (DPC) is the most promising QPI approach to high resolution label-free cellular dynamic imaging because of its advantages of higher imaging efficiency, higher accuracy, and higher stability. Typically, illuminations in DPC systems are designed with 2-axis half-circle amplitude patterns, which however results in a non-isotropic phase transfer function (PTF). Furthermore, the frequency responses of the PTFs have not been fully optimized, leading to suboptimal phase contrast and signal-to-noise ratio (SNR) for phase reconstruction. In this paper, we derive the optimal illumination scheme to maximize the PTF response for both low and high frequencies (from 0 to 2NAobj ), and meanwhile achieve perfectly isotropic PTF with only 2-axis intensity measurements. We present the theoretical analysis, simulations, and experimental results demonstrating that our optimal illumination scheme is a simple, efficient, and stable approach for label-free quantitative cell imaging with subcellular resolution.

We present a new quantitative phase imaging method on the basis of the novel camera named quantitative phase imaging camera with a weak diffuser (QPICWD). It measures object under low-coherence quasi-monochromatic illumination via examining the deformation of the speckle intensity pattern. The speckle deformation can be analyzed by means of ensemble average of geometric flow method, realizing high resolution distortion field by using the transport of intensity equation (TIE). There are some applications for the proposed new design including nondestructive optical testing of microlens array with nanometric thickness. Since the proposed QPICWD needs no modification of the common bright-field microscope, it may promote QPI as a useful tool for subcellular level biological analysis.

Carbon nano-tube (CNT)- and carbon fiber (CF)-filled polyolefin nano-composites were prepared by melt blending. The water absorption, expansion ratio, electrical conductivities, and physical and mechanical properties of the prepared nano-composites were extensively investigated. The experimental results showed that the water absorption increased with the elapsed time from the starting point when the samples were immersed into the water. The linear expansion ratios of the composites were found to increase gradually with time till reaching an equilibrium value. Composites with excellent dielectric properties could be obtained when the filler content was above the percolation threshold. The addition of CNT and CF resulted in no obvious improvement in mechanical properties in the present study, but both Shore hardness and Vicat softening temperature (VST) of the composites increased with increasing filler content. The present work will be of practical importance to the CNT/CF filler composites design,...