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We have demonstrated the realization of a coherent vesicle random lasing (VRL) from the dye doped azobenzene polymer vesicles self-assembled in the tetrahydrofuran-water system, which contains a double-walled structure: a hydrophilic and hydrophobic part. The effect of the dye and azobenzene polymer concentration on the threshold of random laser has been researched. The threshold of random laser decreases with an increase in the concentration of the pyrromethene 597 (PM597) laser and azobenzene polymer. Moreover, the scattering of small size group vesicles is attributed to providing a loop to boost the coherent random laser through the Fourier transform analysis. Due to the vesicles having the similar structure with the cell, the generation of coherent random lasers from vesicles expand random lasers to the biomedicine filed.

Abstract: We were successful in synthesizing periodic layered zinc acetate nanobelts through a hydrothermal solution process. One-dimensional structured ZnO nanoparticle aggregate was obtained by simple thermal annealing of the above-mentioned layered ZnO acetate nanobelts at 300 °C. The morphology, microstructure, and composition of the synthesized ZnO and its precursors were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and infrared spectroscopy, respectively. Low angle X-ray diffraction spectra reveal that as-synthesized zinc acetate has a layered structure with two interlayer d-spacings (one is 1.32 nm and the other is 1.91 nm). SEM and TEM indicate that nanobelt precursors were 100–200 nm in width and possesses length up to 30 μm. Calcination of precursor in air results in the formation of one-dimensional structured ZnO nanoparticle aggregates. In addition, the as-prepared ZnO nanoparticle aggregates exhibit high photocatalytic activity for the photocatalytic degradation of methyl orange (MO).

Replica symmetry breaking (RSB) has been widely recognized as a statistical analysis approach to understand the disorder and nonlinear interactions in complex systems ranging from atoms to the cosmic scale. However, it is challenging to analyze the nonlinear optical characteristics of random laser (RL) in disordered gain medium via RSB due to the lack of a general RSB-based statistical analysis framework. In this work, we report the tunable RSB in polymer fiber RL, where the effects of temperature and different structures on RSB are investigated experimentally and theoretically. It experimentally proves that RSB in RL is not robust, and disorder and temperature are responsible for tunable RSB in RL, which contributes to the improvement of the statistical analysis framework for investigating the optical principles of RL using RSB. And the finding of the tunable RSB allows to investigate the dynamical differences for various RL systems, which broadens the directions for the use of spin-glass theory to explore the physical mechanism of RL.

Sodium‐ion batteries (SIBs) are crucial energy equipment that sustain low cost and better environmental benefit. Nevertheless, the practical energy density of SIBs is limited by cathode material. Over last decades, the iron‐based sulfate (IBS) has been extensively studied owing to its numerous advantages, including a large theoretical specific energy (over 100 Wh kg−1), high working potential (above 3.4 V), low cost, good structural stability, and environmental friendliness. Nevertheless, the application of IBS in SIBs is limited by its unsuitable electrolyte and low electronic/ionic conductivity. This review summarizes recently developed results on IBS materials for SIBs, ranging from the phase diagram–composition structure–electrochemical performance to modification research. A generalized summary of the future prospects of IBS‐based materials is also provided, with the hope of inspiring further advances in their application in SIBs. This article comprehensively reviews the research progress and potential development prospects of iron‐based sulfate from the perspective of phase diagram–composition–structure.

Although many studies on cholesteric liquid crystal (CLC) microdroplet single-mode lasers are available, it has been shown that the stability and tunability of such microdroplets are difficult to achieve simultaneously. In this paper, a new, to the best of our knowledge, method is proposed for the mass and rapid preparation of stable and tunable monodisperse CLC microdroplet single-mode lasers. This is based on the formation of polymer networks on the surface of the microdroplet via interfacial polymerization and a disruption of the orderliness of the polymer networks by increasing the temperature during polymerization, which results in a single pitch inside the microdroplets. This approach enables CLC microdroplet single-mode lasers to achieve improved environmental robustness, while maintaining the same temperature tunability as the unpolymerized sample. Our method has promising future applications in integrated optics, flexible devices, and sensors.

A type of Christiansen filter that takes the form of a smooth cylindrical lens of even symmetry is proposed. By varying the shape of the lens, the filter can be made to realize many common filtering responses, including the polynomial function response, the Gaussian function response, and the sinc function response. A systematic design technique based on inverse scattering is established, and a desired, prescribed response can be tailored by properly shaping the lens of the filter. Three prototypical Christiansen filters, namely, a second-order all-real-roots filter, a second-order sinc filter, and a Gaussian filter, are synthesized using the proposed method. A prescribed response at 545 nm with a FWHM of 2 nm is achieved systematically by all of the three Christiansen filters.

ObjectiveTo assess the impact of preconception alcohol consumption on risk of miscarriage incidence, and further evaluate the association between maternal periconception drinking abstinence and miscarriage.MethodsWe performed a population-based, retrospective cohort study in China between 1 January 2013 and 31 December 2016. Alcohol intake and potential confounding factors were reported in standard questionnaires. Participants who became pregnant were recontacted for pregnancy outcome information within 1 year. A total 4 531 680 women with available data on preconception alcohol intake and miscarriage were included in the final analyses. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).ResultsThe prevalence of miscarriage was 2.70% among 4 531 680 women. Compared with non-drinkers, the adjusted OR of miscarriage was 1.06 (95% CI 1.02 to 1.10) and 1.59 (95% CI 1.15 to 2.20) in maternal occasional drinkers and regular drinkers, respectively. Compared with couples in which neither the male nor the female consumed alcohol, the adjusted OR for miscarriage among women was 1.09 (95% CI 1.07 to 1.10), 1.13 (95% CI 1.06 to 1.21) and 1.12 (95% CI 1.07 to 1.17) in the couples in which only the female drank alcohol, only the male drank alcohol, and both drank alcohol, respectively. The adjusted OR was 0.58 (95% CI 0.51 to 0.65) in women with alcohol abstinence compared with alcohol drinkers.ConclusionsPreconception alcohol consumption was associated with higher odds of miscarriage, and an increasing risk was found with paternal and maternal alcohol drinking. Periconception alcohol abstinence was inversely associated with miscarriage.

To date, various studies have been dedicated to the development of cholesteric liquid crystal (CLC) microdroplet omnidirectional lasers. In this work, a stable and tunable multi-mode laser emission is achieved by designing a dye-doping CLC microdroplet. In such a structure, the polymer network only exists on the surface, maintaining stability while providing tunability, and due to the uneven distribution of the pitch, it leads to multi-mode laser emission. A large number of microdroplets are produced quickly via a new method based on ultrasonic separation. During the reaction, we introduce interfacial polymerization where monomers and photoinitiator are respectively distributed inside and outside the microdroplets through mutual diffusion, which enables one to make the polymer network exist on the surface instead of the interior. The obtained microdroplet-based multi-mode laser is shown to possess stability and tunability, demonstrating a great potential for flexible devices and 3D displays.

In waveguided nematic liquid crystal random lasers (NLCRLs), we realize polarized random laser (RL) emission and discover that the waveguide effect reduces the transmission loss of the RL whose polarization is parallel to the liquid crystal molecules (LCMs). Compared with the traditional liquid crystal random lasers, the waveguide NLCRLs can achieve the regulation of RLs strength, polarization, and wavelength in the same structure. The electric field can drive the rotation of LCMs to control the RL polarization and intensity. The drop of horizontal polarization laser and the increase of vertical polarization laser prove the role of the waveguide effect. In addition, the disorder of the waveguided NLCRLs is highly sensitive to temperature, which makes it easy to control the wavelength and intensity of the RL. As the temperature rises, the waveguide effect is weakened, resulting in a weakening of the restriction along liquid crystal (LC) cell normal direction. The reduced laser intensity verifies the role of the waveguide effect.

The feasibility of the application of terahertz electromagnetic waves in the diagnosis of prostate cancer was examined. Four samples of incomplete cancerous prostatic paraffin-embedded tissues were examined using terahertz spectral imaging (TPI) system and the results obtained by comparing the absorption coefficient and refractive index of prostate tumor, normal prostate tissue and smooth muscle from one of the paraffin tissue masses examined were reported. Three hundred and sixty cases of absorption coefficients from one of the paraffin tissues examined were used as raw data to classify these three tissues using the Principal Component Analysis (PCA) and Least Squares Support Vector Machine (LS-SVM). An excellent classification with an accuracy of 92.22% in the prediction set was achieved. Using the distribution information of THz reflection signal intensity from sample surface and absorption coefficient of the sample, an attempt was made to use the TPI system to identify the boundaries of the different tissues involved (prostate tumors, normal and smooth muscles). The location of three identified regions in the terahertz images (frequency domain slice absorption coefficient imaging, 1.2 THz) were compared with those obtained from the histopathologic examination. The tissue tumor region had a distinctively visible color and could well be distinguished from other tissue regions in terahertz images. Results indicate that a THz spectroscopy imaging system can be efficiently used in conjunction with the proposed advanced computer-based mathematical analysis method to identify tumor regions in the paraffin tissue mass of prostate cancer.

Here we report the chemical synthesis of conjugation-ready trisaccharides, representing biological repeating units of Pseudomonas aeruginosaserotype 10 and 19 O-antigens. The α-d-QuiN3glycosidic bond was stereoselectively synthesized through TMSI─Ph3P═O mediated 1,2-cisglycosylation. Selective oxidation of the C6–OH group at the disaccharide stage allowed for benzylidene-promoted construction of the α-l-GalN3glycosidic bond and simplification of the postglycosylation process at the trisaccharide stage. The low reaction temperature and neighboring electron-donating effect facilitated the efficient synthesis of the trisaccharide.

Coatings with only passive protection cannot offer long-term anticorrosion on metals. Eco-friendly sustainable and responsive coating for active/passive corrosion protection is desirable to extend the service life of metals. Here, benzotriazole (BTA)-metal organic frameworks (Cu-MOFs, UiO-66) were embedded in silica (SiO2) coating by one-step electrodeposition on copper. Combined with passive capability of MOFs and active protection of BTA inhibitor, the composite coating (BTA-MOF/SiO2) exhibited high and stable corrosion resistance, confirmed by microstructure characterizations and electrochemical tests. As a result, the as-prepared composite coating exhibited superhydrophobicity with a water contact angle of 154.2°. With loading of BTA-MOF in SiO2coating, the impedance modulus at 0.01 Hz increased by ∼10-fold and the corrosion current density decreased to 3.472 × 10–9A·cm–2. Immersion and salt spray tests confirmed the long-term protection of the composite coating. The responsive release of BTA inhibitor endows the coating with a responsively anticorrosive behavior. The active-passive ability makes the coating a good candidate for protection on metals used in highly salty environments.

Distinct corrosion behavior was reported in multiphased titanium alloys prepared by additive manufacturing and by traditional technologies because of different phase constituents formed during processing. An open question is therefore raised: is there always different corrosion behavior of materials prepared by different methods? This work reports resemble corrosion behavior of selective laser melted and wrought single β-phase Ti-24Nb-4Zr-8Sn (Ti2448) in both NaCl solution and Hank’s solution. The electrochemical measurements showed that both samples have close calculated polarization resistance and corrosion potential in NaCl solution, i.e., 4.99 ± 0.63 MΩ cm2and −0.26 ± 0.01 V for the selective laser-melted Ti2448, and 4.42 ± 0.71 MΩ cm2and −0.25 ± 0.01 V for the wrought Ti2448, respectively. Both samples reveal the same variation in weight change after 180-day immersion test in Hank’s solution. Such resemblance in corrosion behavior without pitting morphologies is attributed to the formation of monolithic β-phase during processing, which demonstrates that titanium alloys with single phase show comparable corrosion behavior regardless of the manufacturing methods adopted.

This paper systematically demonstrated a variety of experimental phenomena of random lasers (RLs) of N,N′-di-(3-(isobutyl polyhedral oligomeric silsesquioxanes)propyl) perylene diimide (DPP) organic/inorganic hybrid laser dye, which is composed of perylene diimide (PDI) as gain media and polyhedral oligomeric silsesquioxanes (POSS) as scattering media at a mole ratio of 1:2. In this work, we observe the transition from incoherent RL in the DPP-doped solutions and polymer membrane systems using dip-coating method to coherent RL in the polymer membrane system with defect waveguide using semi-polymerization (SP) coating method. Meanwhile, we found that the hybrid dye-DPP has a long lasing lifetime compared with the traditional laser dyes, which indicates that the POSS group can suppress the photo-bleaching effect to extend the working life of laser dyes.

Although the corrosion behavior of metals under thin electrolyte layers (TELs) has been widely studied, little is understood about the electrode processes under these layers and even less so when exposed to a direct current (DC) electric field. This work shows that the open circuit potential (OCP) shifts negatively, the current density of oxygen reduction increases and initial hydrogen evolution potential shifts positively with enhancing the DC electric field intensity. The OCP shifts positively under the polarity reversal of DC electric field. The area covered with corrosion product decreases with increasing DC electric filed intensity. All these results indicate that the applied DC electric filed promotes the corrosion resistance of carbon steel. The synergistic effect of electric field on the electrode process of TELs has also been discussed in depth.

Ti-6Al-4V alloy produced by selective laser melting (SLM) was reported to exhibit an inferior corrosion resistance compared with the traditionally processed Grade 5 alloy, due to the formation of high-energy metastable a' martensite with regard to a martensite. This work manipulates the transformation of a' martensite to a martensite by heat-treatment in SLM-produced Ti-6Al-4V alloy and studies the effect on its corrosion behavior using electrochemical tests and microstructural analysis. The electrochemical results reveal that the heat-treated SLM-produced samples exhibit a higher corrosion rate than the as-received counterparts. The microstructural characterization results show that the acicular a' martensite vanishes gradually, and a plate-shaped a phase and a lamellar a + b mixture continuously form with enhancing heat-treatment temperature, which increases the grain size. The relation between changes in grain size and corrosion resistance of SLM-produced Ti-6Al-4V has been discussed in detail.

Tuning transversal resonance modes of localized surface plasmons (LSPs) by the size and the ambient dielectric medium of Ag nanorods is presented. It is found that the resonance wavelength and intensity of the transversal modes of LSPs are closely related to the dimensions of the Ag nanorods embedded in anodic aluminum oxide membranes. The transversal resonance peak exhibits obvious redshifts from 365 to 396 nm with increasing nanorod diameter from 40 to 80 nm, and the resonance intensity remarkably enhances with increasing nanorod diameter. In addition, it is observed that the transversal resonance modes of LSPs in Ag nanorods are strongly sensitive to their surrounding dielectric medium such as water, ethanol, and cetyltrimethylammonium bromide, and the transversal resonance peak distinctly redshifts from 422 to 467 nm when the refractive index of the dielectric medium increases from 1.342 to 1.435. As a result, a refractive index sensitivity of up to 484 nm/RIU can be achieved based on the transversal resonance modes. The transverse resonance modes of LSPs in the Ag nanorods can be used for sensitive quantification of chemical and biological species.

There are many kinds of materials or methods used to make optical microcavities, and they have many different geometric structures. And electrospinning technique has become a very convenient and easy one to prepare polymer fiber. Based on this situation, PM597-doped polymer solution was prepared into high-performance fibers with different diameters by electrospinning technology in our work. In order to better study the temperature sensing of polymer fiber whispering gallery mode, we have placed it on two different substrates with gold and aluminum. A 532 nm pulsed laser beam was used to excite a single fiber in the radial direction, then the whispering gallery mode (WGM) laser was observed and the distribution of WGM was determined by theoretical calculations. The threshold of samples on aluminum substrate is 0.4 μJ. In addition, it is found that the samples on aluminum substrate performed better in temperature sensing, and the value is 0.13 nm/°C. As a result, WGM polymer fiber microcavities on aluminum substrate made by electrospinning technology have very broad development prospects in biosensing, optical pump lasers and other applications.

Layered titanates (Na2Ti3O7·nH2O) with exchangeable sodium cations located in the interlayer have been synthesized by simple hydrothermal treatment of Ti precursor in concentrated NaOH solutions. By proper control of the synthesis conditions, different morphologies of nanofibers and nanosheets are obtained. The metastable layered structure of the titanates collapses during the ion exchange, resulting in irreversible ion exchange. Target cations (eg., Ag+, Cu2+, Pb2+and Eu3+) are completely concentrated from water and then tightly immobilized in the interlayer which is of great significance for the removal and subsequent safe disposal of hazardous metal cations. The ion exchange of the nanosheets is much more efficient than that of the nanofibers and other inorganic ion exchangers due to the larger surface area, less stable layered structure and larger amount of interlayer water of the nanosheets. The ion exchange of the titanates is also very selective. Valence, hardness, and radius of cations are main factors affecting the selectivity. Cations trapped in the interlayer are released by an acid‐induced phase transformation of the titanate nanosheets to rutile. Then the rutile can be used as a new Ti precursor to synthesize the titanate nanostructures, resulting in a full cycle of material use. The nanosheets may find applications in the decontamination and safe disposal of radioactive and heavy metal cations and also in the collection of valuable cations from water.

In order to study the propagation mechanism of business cycles, in particular to investigate how the intensity of competition affects market structure and output persistence over business cycles, this paper presents a real business‐cycle model with imperfect competition and increasing returns to scale. This analysis considers the markups of price over cost to be endogenous. With endogenous markups, two standard forms of oligopolistic competition—Bertrand and Cournot—are considered. Results show that: (1) the propagation mechanism in the sense of output persistence is greater under Cournot; (2) the propagation mechanism is unequivocally greater with imperfect competition, regardless of whether markups are endogenous or not; and (3) under imperfect competition, the propagation mechanism is greater with endogenous markups than with exogenous markups. Overall, these results suggest that more intense competition produces lower persistence in output growth and, thus, a weaker propagation mechanism. In a calibration exercise, these differences were also found to be quantitatively important.

Polarization characteristics of microarrays of silver nanowires embedded in an anodic alumina membrane are theoretically investigated. The microarrays mainly transmit the p-polarized wave, whereas they strongly attenuate the s-polarized wave in the near- and mid-infrared spectral range. We show that the sizes (e.g., diameter, spacing, and ratio of diameter to spacing) of the nanowires strongly affect the optical losses for the polarized waves. It is predicted that large extinction ratios and small insertion losses can be simultaneously achieved by an appropriate choice of the ratio and the diameter. An optimized design of a nanowire grid polarizer at near- and mid-infrared wavelengths is presented.

Abstract.: This paper studies the equilibrium dynamics and indeterminacy of equilibria in an endogenous growth model with endogenous fertility choice. We characterize the conditions that give rise to an unique equilibrium as well as multiple equilibria. Whenever there exists a unique equilibrium, it will be globally determinate; when multiple equilibria arise, indeterminacy occurs. In particular, we find that two equilibria occur – one is associated with high fertility and low growth, while the other is associated with low fertility and high growth. A parameterized example is given to assess the empirical feasibility of our results. The validity of the neo-Malthusian relation between fertility and growth is then re-examined. Finally, we study the relation between growth and welfare and compare different balanced growth equilibria in terms of their lifetime-attained utility. JEL classifications: O41, J13

This paper studies the liquidity effect in a pecuniary transaction‐cost model. To model the asymmetric impact of monetary injections, we consider two behavioral assumptions: sluggish money demand and sluggish firm investment. It is found that, under reasonable parameterization, the model is capable of generating a dominant liquidity effect. Our result suggests that, with alternative monetary specifications and behavioral assumptions, general equilibrium models are still useful for studying the liquidity effect at business cycle frequencies.

A pin-on-disk friction and wear test was conducted to test the critical load for serious dry sliding wear of Vanadis 4 Extra steel at a sliding speed of 0.691 m/s, at room temperature, 200 degC and 400 degC respectively. Using scanning electron microscopy (SEM) and an energy dispersive spectrometer (EDS), the wear surface morphologies, wear mechanism and reasons were analysed. Results show that: with increasing temperature, the critical load for serious wear of Vanadis 4 Extra steel first increased and then decreased. The critical loads leading to serious wear were 900 N and 800 N at room temperature and 400 degC, respectively, while, there was no serious wear at 200 degC at less than 1000 N. There were abrasive particles found under different loads: as the load and temperature increased, the formation of oxide films on the worn surface plays an decisive role in wear: when applying a load smaller than the critical load, oxide films can protect and lubricate the steel substrate, presenting slight oxidative wear; when applying a load greater than the critical load, oxide films on the worn surface were ruptured and spalled, with mainly oxidative delamination wear being observed.

Although the corrosion behavior of metals under thin electrolyte layers (TELs) has been widely studied, little is understood about the electrode processes under these layers and even less so when exposed to a direct current (DC) electric field. This work shows that the open circuit potential (OCP) shifts negatively, the current density of oxygen reduction increases and initial hydrogen evolution potential shifts positively with enhancing the DC electric field intensity. The OCP shifts positively under the polarity reversal of DC electric field. The area covered with corrosion product decreases with increasing DC electric filed intensity. All these results indicate that the applied DC electric filed promotes the corrosion resistance of carbon steel. The synergistic effect of electric field on the electrode process of TELs has also been discussed in depth.

Ti-6Al-4V alloy produced by selective laser melting (SLM) was reported to exhibit an inferior corrosion resistance compared with the traditionally processed Grade 5 alloy, due to the formation of high-energy metastable α′martensite with regard to α martensite. This work manipulates the transformation of α′martensite to α martensite by heat-treatment in SLM-produced Ti-6Al-4V alloy and studies the effect on its corrosion behavior using electrochemical tests and microstructural analysis. The electrochemical results reveal that the heat-treated SLM-produced samples exhibit a higher corrosion rate than the as-received counterparts. The microstructural characterization results show that the acicular α′martensite vanishes gradually, and a plate-shaped α phase and a lamellar α + β mixture continuously form with enhancing heat-treatment temperature, which increases the grain size. The relation between changes in grain size and corrosion resistance of SLM-produced Ti-6Al-4V has been discussed in detail.