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Attaching AIE-active L1 ([1,1':2',1'':4'',1'''-quaterphenyl]-2-yldiphenylphosphane) to AuCl, shortened the distances of P-C bonds to promote electron cloud overlap between Au I and L1 , affords 1 ( L1 AuCl) with aggregation-induced phosphorescence enhancement (AIPE) activity by 3 LMCT transitions. Then substituting the coplanar L2 (9-ethynylanthracene) for the Cl - in 1 providing 2 , switches the luminescence to aggregation-caused quenching (ACQ) activity. Furthermore, we restore the performance from ACQ to AIPE by metathesis reactions to transfer 2 into 1 . It is versatile synthetic strategy of reversible transformation between 1 and 2 that switches the luminescence of organogold(I) between AIPE and ACQ through balancing auxiliary ligands around the given metal.

Variable Angle Tow placement is a way to steer individual curvilinear fibers. This work presents the assessment of tensile behavior of open-hole composite laminates with Variable Angle Tow reinforcement. A new multi-scale finite element method, consisting of a microscale unit cell model and a macroscale gradient property model, is developed to simulate Variable Angle Tow structures with various fiber trajectories. The tensile strength and the failure process of open-hole reinforced laminates with Variable Angle Tow reinforcement under tensile loading are predicted and analyzed. Experiments are also conducted to investigate reinforcing efficiency and failure modes of the open-hole laminates. The comparison of predicted and experimental results for the tensile strength and failure modes of T700/Epoxy laminates demonstrates clearly that the mechanical behavior of Variable Angle Tow structure can be simulated very well by the proposed multi-scale model. Moreover, it is found that the tensile strength of Variable Angle Tow laminates is closely related to the eccentricity and it reaches the maximum value only when the trajectories of curvilinear fibers keeps consistent with maximum principal stress trajectories of the open-hole plate.

Objective To compare the diagnostic performance between Prostate Imaging Reporting and Data System version 1(PI-RADS v1) and PI-RADS v2 for detection of prostate cancer (PCa). Methods A systematic literature search was performed from inception to September 31, 2018, in following databases MEDLINE, EMBASE, Cochrane Library, Google Scholar, in addition to Chinese National Knowledge Infrastructure (CNKI) and Wanfang Data database. Sensitivity and specificity of individual studies along with summary estimates were calculated and presented in forest plots. Multiple subgroup analyses and meta-regression were performed to investigate the heterogeneity. Quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Results 14 studies involving head to head comparison between PI-RADS v1 and v2 were included, with a total of 1682 patients. The pooled sensitivity for PI-RADS v1 and PI-RADS v2 were 85.37% (95% CI 79.29%–89.89%) and 87.79% (95% CI 79.84%–92.88%), with pooled specificity of 77.26% (95% CI 57.29%–89.58%) and 76.73% (95% CI 58.69%–88.44%), respectively. There was no substantial difference in diagnostic accuracy between PI-RADS v1 and PI-RADS v2 (P = 0.57 for sensitivity and P = 0.96 for specificity). Multiple subgroup analyses and meta-regression suggested these two scoring systems had comparable diagnostic performance on magnetic field strength, zonal anatomy, and outcome assessment. For the transitional zone, it seemed that PI-RADS v2 had higher sensitivity than PI-RADS v1 (90.1% vs. 80.59%), but the difference was not substantial (P = 0.17). Conclusion PI-RADS v2 has slightly higher sensitivity but at the expense of minor decreased specificity. Thus, on the whole PI-RADS v1 and PI-RADS v2 have comparable diagnostic accuracy.

The mechanical properties of carbon fiber (CF) reinforced composites are greatly dependent on the interfacial adhesion between fiber and resin matrix. Introducing nanoscale reinforcements into the interface is an effective approach to improve the interfacial adhesion of CF composites. In this paper, we proposed a facile and effective method for assembling poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) nanotube onto CF surface as a novel multi-scale hybrid reinforcement through in situ template polymerization. The effects of surface modification on the surface and interface properties of CF and the resulting composite were investigated. After modification, the interfacial shear strength of fiber reinforced epoxy composites showed an increase of 26.4%. The reinforcing mechanisms were also analyzed, and the improvements on interfacial properties should mainly be attributed to mechanical interlocking effect. In addition, the modification even improved the fiber tensile strength by 6.6–16.3%, rather than deteriorating it.

In this study, a nickel coated carbon fiber (Ni-CF) tow is used to enable glass fiber reinforced plastics (GFRPs) to exhibit multi-functional properties with self-diagnosing function. The experimental results indicate that the Ni-CF exhibits desirable interfacial compatibility with the matrix resin and has no negative effect on the performance of GFRPs, thereby the loading conditions can be effectively monitored without deterioration. The electro-mechanical response suggests that the changes in resistance can be further divided into two stages corresponding to the two different safety states based on the strain under uniaxial tensile loading. At the same time, the composites were examined under cyclic loading conditions to confirm the stability and robustness of the Ni-CF as a sensing element. Moreover, the safety factor and reliability of composites were calculated based on the stress corresponding to the transition point of the safety states and the ultimate stress of the composites. Consequently, the results show that the reliability is close to 100% when the maximum safety factor of Ni-CF/GFRP is 1.5. In addition, we also suggest two different solutions for manufacturing self-diagnosing composites which can be individually applied in the development of the structures with low failure risk or with high safety requirements.

The existing valence state (Eu2+/Eu3+ and Tb3+/Tb4+) in Eu/Tb ions doped in SrAl2Si2O8 were investigated through experimental and theoretical method. Their photoluminescence properties indicated that parts of Eu3+ ions were reduced to Eu2+ in SrAl2Si2O8. Based on the bond energy method, the reduction process of the Eu3+→Eu2+ and the preferentially occupancy of Eu3+/Eu2+ in SrAl2Si2O8 samples have been discussed. The values of deviation of its bond energy were calculated when Eu ions located at different crystal sites. Theoretical results indicated that the Eu3+ and Eu2+ would preferentially occupy the Sr sites due to the smaller energy variation. In addition, the variation of bond energy of Eu3+( Δ E Eu 3 + - O 2 - Sr =11.367 kcal/mol) is close to Eu2+ ( Δ E Eu 2 + - O 2 - Sr = 15.112 kcal/mol), which indicated that the both of Eu2+ and Eu3+can stably exist in SrAl2Si2O8 host. When Eu, Tb ions are co-doped in SrAl2Si2O8, the photoluminescence shows that only the characteristic emission peaks of Eu2+ and Eu3+ can be found and the emission of Tb3+ disappeared. It is suggested that the Tb3+ is oxidized to Tb4+ and the Eu3+ is reduced to Eu2+. Compared with Eu ion, the variation of bond energy for Tb3+( Δ E Tb 3 + - O 2 - Sr =10.084 kcal/mol) is more closer to Tb4+ ( Δ E Tb 4 + - O 2 - Sr =9.628 kcal/mol), so in Tb3+, Eu3+ co-doped in SrAl2Si2O8, the Tb4+ ion has the highest priority to occupy the Sr sites, Tb3+ loses one electron to form the tetravalent Tb4+, and the excess electrons are transferred to the surrounding neighboring Eu3+ site, Eu3+ gets an electron and is reduced to Eu2+. The theoretical results are in accord with the experimental measurement.

The paper proposes the novel Variable Angle Tow (VAT) placement technique to create local reinforcement on fiber reinforced composites with holes which enables to optimize the design for variable stiffness laminates by placing continuous fiber to follow the pre-calculated principle stress trajectories automatically. The potential factors influencing the strengthening effect are investigated, including reinforcement types, lay-up configurations and dimensions. The results from tensile test discusses the failure modes and reveals that with VAT reinforcement, especially the elliptical reinforcement, the ultimate strength of the open-hole specimen can be significantly improved compared with the plain cloth reinforcement. It is also found that the double-sided reinforcement configuration is superior to single-sided or interlayer configurations, and both the circular and elliptical VAT reinforcements possess their optimal dimensions when considering the weight. Subsequent Finite Element Analysis indicates the reinforcing mechanism that the stress concentration in the reinforced region is alleviated by redistributing the stress to the outer unreinforced region.

Graphene oxide (GO) was grafted onto the surface of carbon fiber (CF) by two synthetic routes with hexamethylene diisocyanate (HDI) tripolymer as the coupling agent. The first one was to use HDI tripolymer to modify the surface of GO, named GO-NCO, and then graft GO-NCO onto the oxidized carbon fiber surface. The other route was to use HDI tripolymer to modify the oxidized carbon fiber surface, named CFO-NCO, and then graft GO onto the CFO-NCO surface. The chemical compositions of the CF surface were confirmed by infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS). The surface morphologies of CF after modification and debonding from matrix were examined by scanning electron microscopy (SEM). The interfacial shear strength (IFSS) of CF/PA6 composites was also investigated by microbond test. It is found that the interfacial properties of GO modified carbon fiber reinforced polyamide 6 (CF-g-GO/PA6) composites are better by using the first route. The IFSS of CF-g-GO/PA6 composites reaches 61.4 MPa, is an increase of 40.2% compared with that of unmodified CF/PA6 composites. Moreover, the interfacial enhancement mechanism was further analyzed in detail.

Eu-doped MAlSi2O6 (M = Li, Na, K, Rb, Cs) phosphors were synthesized by solid-state reaction in air. The crystal structure and optical properties of the phosphors were investigated by X-ray powder diffraction and photoluminescence. Their emission spectra are composed of some broad bands coming from the 5d-4f transition of Eu2+ and some sharp emission peaks coming from the f-f transitions of Eu3+. The co-existence of Eu3+ and Eu2+ cations is detected in MAlSi2O6:2%Eu, which shows that the unusual Eu3+→Eu2+ reduction process occurs in MAlSi2O6. The preferential occupancy of Eu3+ or Eu2+ in MAlSi2O6 can be calculated to be M+ sites by the bond-energy method. The deviation of the Eu3+–O2- bond energy is closed to that of the Eu2+–O2- bond energy, which means that Eu3+ and Eu2+ can coexist in air. The abnormal reduction of Eu3+ to Eu2+ can be explained by charge compensation model. The doped Eu3+ was induced to M+ and the vacancy (VM) may be formed. The vacancy(VM) acted as a donor of electrons, and the Eu M ∙ ∙ defect acted as an acceptor of electrons. The theoretical result is consistent with the experimental phenomenon.

A bond-energy method is used to determine the site occupancy preference of Eu3+ or Eu2+ and further firstly extended to study the spontaneous reduction of Eu3+ doped CaAl2Si2O8 based on the bond valence model. The phosphor CaAl2Si2O8: Eu was synthesized under air condition. The co-existence of Eu3+ and Eu2+ cations was detected through photoluminescence measurement. The occupancy of Eu3+ or Eu2+ in CaAl2Si2O8 can be determined by comparing the deviation of its bond energy in different locations at Ca2+, Si4+ and Al3+ sites. Theoretical calculation result indicates that the Eu3+ and Eu2+ would preferentially occupy the smaller energy variation sites Ca4, which can be assigned to Eu4 site. The more important result is that the energy variation of Eu2+ at Eu4 sites is smaller than that of Eu3+ at the same sites, which indicates that Eu2+ is more stable than Eu3+ at Eu4 sites, so the spontaneous Eu3+→Eu2+ reduction can be found in the CaAl2Si2O8. The same bond energy method can be extended to explain the reason why the Sm3+ doped CaAl2Si2O8 can't be reduced into Sm2+ under reduction condition. The theoretical result is consistent with the experimental phenomenon. This should help us to have a further understanding of spontaneous Eu3+→Eu2+ reduction in the inorganic material.

The local crystal sites occupied by Eu3+ in Ca5(BO3)3F:1% Eu3+ phosphor were investigated experimentally and theoretically. Ca5(BO3)3F:1% Eu3+ was synthesized by high-temperature solid-state method in air. The crystal structure and optical properties of the phosphor were studied by X-ray powder diffraction and photoluminescence, respectively. Two different O2− → Eu3+ CT broad bands with the peaks at 266 and 283 nm in Ca5(BO3)3F:1% Eu3+ were detected, indicating the Eu3+ sites occupied Ca2 and Ca1, respectively. The different sharp f–f emission spectra under the excitation of 283 and 266 nm proved that there are two different local lattice environments around Eu3+ existing in Ca5(BO3)3F:1% Eu3+. Environmental factor he, the standard deviation of environmental factor (EFSD) and the bond energy were used to illustrate and explain the site occupancy mechanism of Eu3+ into the host lattice. By comparing the intensity ratios of 5D0 → 7F2 transition to the 5D0 → 7F1 transition, I(5D0/7F2)/I(5D0/7F1) of Eu3+ at Ca2 (7.381) was found to be 2.5 times stronger than that of Eu3+ at Ca1 site (2.933). was calculated to analyze the I(5D0/7F2)/I(5D0/7F1) value. On the basis of the bond valence model, a bond-energy method was used to study the occupancy of the Eu ion, which indicated that the preferential sites of Eu ion occupancy in the Ca5(BO3)3F are the Ca2 and Ca1 sites. All three theoretical calculation results are consistent with each other.

CaY1−xAl1+xO4:2%Eu (x = 0, 0.1, 0.2) phosphors have been synthesized via a solid-state reaction process. XRD patterns indicate that they are pure phase. The photoluminescence properties of the CaY1−xAl1+xO4:2%Eu phosphors exhibit both the blue emission of Eu2+ (4f65d1–4f7) and red-orange emission of Eu3+ (5D0–7F1,2,3,4) under UV light excitation, which showed that the Eu3+/2+ co-doping system was obtained by adjusting the Al/Y ratio. Eu3+ ions can be reduced to Eu2+ ions when the Al/Y ratio was changed. In this work, the bond energy method was used to determine and explain the mechanism of the site occupation of Eu ions entering the host matrix. Also, the emission spectrum showed an unusual comparable intensity 5D0–7F4 transition peak. The relative intensity of 5D0–7F2 and 5D0–7F4 can be stabilized by changing the relative proportions of Al3+ and Y3+. Furthermore, this was explained by the J–O theory.

The dependence of photoluminescence (PL) properties of Eu 3+ activated two typical vanadates Ca 3 (VO 4 ) 2 and Ca(VO 3 ) 2 on the crystal structure was discussed experimentally and theoretically. Compared with the broad PL excitation spectrum of Ca 3 (VO 4 ) 2 : Eu with the peak at 339 nm, a 61-nm redshift of Ca(VO 3 ) 2 : Eu (at 400 nm) can be found. Under the excitation of near-UV light, the PL spectra of Ca 3 (VO 4 ) 2 :Eu and Ca(VO 3 ) 2 :Eu dominate red emission at 624 and 615 nm due to the 5 D 0 → 7 F 2 transitions, respectively. By comparing their intensity ratios (R/O) of the 5 D 0 → 7 F 2 transition (red, its intensity is labeled using “R”) to the 5 D 0 → 7 F 1 transition (orange, its intensity is labeled using “O”), R/O of Ca 3 (VO 4 ) 2 :Eu is 10 times stronger than that of Ca(VO 3 ) 2: Eu, which can be well explained by the proposed calculation model. Based on the dielectric theory of complex crystal, the important chemical bonds such as the covalency and the polarizability of the O-V or O-Ca bond volume were calculated quantitatively. It was shown that their broad excitation spectra were not the charge transfer (CT) from O to Eu, but is the CT from O to V, which also can be further demonstrated by the optical properties and the density functional theory calculations. Only O-V1 CT energy can efficiently be transferred to the activator due to the strong covalency of V1-O1 bond (0.2583) in the V- O -Eu bond. When Eu 3+ ions occupy the Ca1, Ca2, Ca3, Ca4 and Ca5 sites of Ca 3 (VO 4 ) 2 , the CT energy from O to Eu (O-Eu CT) can be predicted to be 6.22 eV (199 nm), 5.55 eV (223 nm), 5.57 eV (222 nm), 4.31 eV (287 nm) and 3.62 eV (342 nm), respectively. The predicted O-Eu CT energy in the Ca(VO 3 ) 2 : Eu is 4.02 eV (296 nm). For Eu 3+ doped Ca 3 (VO 4 ) 2 sample, the strongest red emission mainly comes from the substitution of Eu 3+ to the Ca5 site through calculation of the distortion degree using the standard deviation of environmental factor of the individual bond (EFSD) σ ( h e i ) . The bandgap energies of Ca(VO 3 ) 2 , Ca(VO 3 ) 2 : Eu, Ca 3 (VO 4 ) 2 and Ca 3 (VO 4 ) 2 : Eu were also determined.

A facile design of interpenetration-structured p–n heterojunction device was fabricated by overlapping p-CuO and n-ZnO nanorod arrays directly. The design showed weak photovoltaic performance. However, the p-n heterojunction system shows the significantly enhanced photocurrent and photovoltage with the assistance of filling electrolyte (I3 −/I−). The charge carrier dynamics indicates that the reversible redox couple (I3 −/I−) electrolyte can promote electron transfer from CuO to ZnO better, i.e. better charge separation efficiency and photocurrent.

A series of CaF 2 :xEu 3+ (x = 0.01–0.05) phosphors were synthesized by coprecipitation and high temperature solid-state method. Three different F - -Eu 3+ charge transfer (CT) bands in CaF 2 :xEu 3+ (x = 0.01–0.05) were detected through the PL spectra. Three local crystal environments (deformed O h octahedron, C 3V , C 4V ) were proposed in Eu 3+ doped CaF 2 . The broad peak at 277 nm is F - → Eu 3+ CT peak, in which Eu 3+ ions located deformed O h octahedron sites, the broad peak at 312 nm is due to Eu 3+ ions situating at C 4v sites, also, Eu 3+ ions with C 3v sites can make the F - → Eu 3+ CT produce a 38-nm redshift to 315 nm. Density functional theory (DFT) was performed to calculate the energy band gap(Eg) according to the three models. The calculation results consist with the experiment. The excitation peaks can be tuned in the same host through changing the local structure of Eu 3+ .

Introducing nanoscale reinforcements into the interface between carbon fiber (CF) and resin is an effective approach to improve the interfacial adhesion of CF composites. In this paper, a facile one-pot polymerization process provides a rapid and efficient method for preparing polyphosphazene microspheres/CF hybrid reinforcement using hexachlorocyclotriphosphazene (HCCP) and bis(4-hydroxyphenyl) sulfone (BPS) as monomers. By the in situ polymerization modification, HCCP and BPS were successfully cross-linked and deposited on the CF surface. Scanning electron microscope and atomic force microscopy images show that poly(cyclotriphosphazene- co -4,4′-sulfonyldiphonel) microspheres were introduced onto the CF surfaces and the surface roughness of fibers is enhanced obviously. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirm that the polymerization between HCCP and BPS has been successfully carried out. The surface modification can significantly increase the fiber roughness, polarity, wettability and surface energy, thus improving the interfacial shear strength of CF/epoxy composites. Meanwhile, the single fiber tensile strength of CF also shows an increase after modification.

Continuous glass fiber (GF)-reinforced polymerized cyclic butylene terephthalate (pCBT) composites were prepared via vacuum-assisted resin transfer molding using butyltin tris(2-ethylhexanoate) as the catalyst. The relationship between melt viscosity and polymerization time was examined in the ring-opening polymerization of CBT resin. The effects of polymerization conditions such as catalyst content and polymerization temperature on viscosity average molar mass ( Mv), crystallization, mechanical properties, and microstructure of GF/pCBT composites were also investigated in detail. It is found that both high molecular weight and high degree of crystallinity of resin matrix can lead to high mechanical properties of composites. The composites prepared with 0.5% catalyst at 190°C show the best mechanical properties with tensile strength of 549 MPa, flexural strength of 585.2 MPa, and interlaminar shear strength of 47.1 MPa. The scanning electron microscopy analysis also demonstrates that good interfacial adhesion exists between fiber and resin, which agrees very well with experimental results.

A family of curves based fiber path optimization approach is developed to optimize the fiber paths in composite laminate with a centered hole, in an attempt to improve the uniaxial tensile load carrying capabilities. In the proposed optimization method, a novel family of curves with two design variables is assumed to approximate the fiber paths in composite laminate. The principal stress trajectories are chosen as the desired fiber paths in order to make full usage of the mechanical properties of continuous fibers. The objective function is constructed by the nonlinear weighted least squares method, taking the first principal stress components as the weights. Using the Trust-Region-Reflective algorithm, the design variables appeared in the family of curves can be optimized. Once the optimal design variables are obtained, consequently, the fiber paths are optimized. With the obtained optimal path results, a comparative study will be given by means of two laminates, the path optimized laminate and the unidirectional laminate. Four failure criteria will be used to evaluate the maximum strength indexes of the laminates under a uniaxial tensile load. From the finite element results, it is shown that the maximum strength indexes can be reduced by 19%–39% when using the fiber path optimized laminate. Meanwhile, the tensile testing results of these two laminates also agree well with the predicted maximum strength indexes.

A convenient fabrication process about the ultrathin broadband composite microwave absorption material (MAM), which involves a frequency selective surface (FSS) sandwiched between two different magnetic sheets, is presented in this letter. The FSS consists of an array of elements with the geometry of square-loop having a split in each edge (denoted as edge-split square-loop FSS). The top and bottom magnetic sheets were prepared based on silicon rubber filled with sphere-shaped and flake-shaped carbonyl iron powders, respectively. It is revealed by measurement and simulation results that the composite MAM with the FSS that induces multiple resonances has a broad operating bandwidth compared to the traditional magnetic MAM without FSS. The low-frequency resonance can be manipulated by adjusting the size of the split $S$ , while the high-frequency resonance is generally invariable. The composite MAM with the thickness of 2.2 mm has an operating bandwidth with the reflectivity below −10 dB in the frequency range of 4–18 GHz, which is nearly 2.7 times the bandwidth of the traditional magnetic MAM.

The cyclomatrix-type polyphosphazene is hypothesized to have potential as optical material due to the existing of transparent P=N ring skeleton. However, as an insoluble and infusible cross-linked polymer, cyclomatrix-type polyphosphazene is very difficult to be processed into film coatings. Herein, we reported a facile in situ template method to prepare cyclomatrix-type polyphosphazene optical film coating based on in situ polymerization between chlorocyclophosphazene and 4,4’-oxydianiline. A transparent coating with smooth surface and a translucent coating with uneven surface were successfully obtained by controlling reaction time. Their molecular structures, surface morphologies and topographies, cross-section morphologies, optical properties and preparation mechanisms were studied, respectively. As expected, the novel film coatings had good transmission in the visible region, especially the smooth transparent coating, which exhibited high transmittance (80 ∼ 90%). Moreover, the coatings unexpectedly exhibited UV-shielding capacity, especially the uneven translucent coating, which blocked the vast majority of UVA radiation (78.6%) and almost all of UVB radiation (99.8%). In addition, the possible preparation mechanisms of two coatings were also discussed. The primary stage of polymerization was dominated by a film-forming process based on template self-assembly, leading to smooth transparent film coating. As polymerization progress, many cyclomatrix-type polyphosphazene microspheres were produced by a forming-microsphere process and then deposited on the film surface, forming uneven translucent coating.

To improve the interfacial adhesion of carbon fiber reinforced polymer composites (CFRP), carbon fiber usually has to be carried out surface treatment under harsh conditions. However, enhancing the interfacial property is usually accompanied by deteriorating tensile strength of carbon fiber, due to some defects on fiber surfaces after surface modification. In this paper, a layer of amine-capped poly (cyclotriphosphazene- co -4,4′-oxydianiline) coating was introduced onto the carbon fiber surfaces by a facile in-situ polymerization under mild condition. The amines on polyphosphazene coating surface help to improve the surface wettability and activity of carbon fibers, significantly improving the interfacial shear strength of carbon fiber/epoxy composites by 70.5%. Besides the enhanced surface wettability, the chemical bonds also play a key role in such an interfacial enhancement. Moreover, the polyphosphazene sheath can heal the surface defects of fiber effectively, thus increasing the fiber tensile strength by more than 10.0%.

The flaky FeSiAl/ irregular shaped MnO 2 composite with the different mass ratios were prepared by using a two-roll mixer and a vulcanizing machine. The morphologies of the composite absorbers were characterized by a scanning electron microscope. The microwave electromagnetic properties of the composites were measured using a vector network analyzer in the range of 1–18 GHz. The effect of the mass ratio of FeSiAl/MnO 2 on the microwave loss properties of the composites was investigated. The results show that the reflection loss (RL) values exceeding −20 dB from 3.5 to 16.5 GHz can be obtained for the flaky FeSiAl/MnO 2 mass ratio of 1:1 from 1.5 mm to 5 mm. In addition, the FeSiAl/MnO 2 composite with the FeSiAl/MnO 2 mass ratio of 7:3 has −10 dB bandwidth of 6.6 GHz (from 11.4–18 GHz) with a thickness of 1.5 mm. It is found that the flaky FeSiAl/MnO 2 composites can be potential microwave absorption materials.

Selenium (Se) is generally known as an essential micronutrient and antioxidant for humans and animals. Aflatoxin B1 (AFB1) is a frequent contaminant of food and feed, causing immune toxicity and hepatotoxicity. Little has been done about the mechanisms of how Se protects against AFB1-induced immune toxicity. The aim of this present study is to investigate the protective effects of Se against AFB1 and the underlying mechanisms. The primary splenocytes isolated from healthy pigs were stimulated by anti-pig-CD3 monoclonal antibodies and treated by various concentrations of different Se forms and AFB1. The results showed that Se supplementation alleviated the immune toxicity of AFB1 in a dose-dependent manner, as demonstrated by increasing T-cell proliferation and interleukin-2 production. Addition of buthionine sulfoximine abrogated the protective effects of SeMet against AFB1. SeMet enhanced mRNA and protein expression of glutathione peroxidase 1 (GPx1), selenoprotein S (SelS), and thioredoxin reductase 1 w...

The three-layer ultrathin radar absorbing structure (RAS) involving a frequency selective surface (FSS) exhibiting excellent broad bandwidth properties is designed and fabricated. The EW and flaky carbonyl iron powders were used to produce two kinds of silicone rubber matrix magnetic composites for the top and the bottom layer, respectively. The electromagnetic parameters of the composites were measured in the frequency range of 2–18 GHz. The middle layer is an FSS in the form of double-square loops with four micro-split gaps in the middle of the outer loop. The results show that the proposed RAS can provide a 10 dB absorbing bandwidth of 13.2 GHz from 4.8 to 18 GHz (1.7 mm thickness) and a 10 dB absorbing bandwidth of 14.1 GHz from 3.9 to 18 GHz, covering C-band, X-band and Ku-band (2.0 mm thickness). A good match between simulation and measurement results demonstrates the validity of our design.

CaY

Ca10M(PO4)7:Eu (M = Li, Na, K) phosphors have been synthesized via a solid-state reaction process, their phase purity was examined using XRD patterns, and Rietveld refinement confirmed that the Ca10Li(PO4)7, Ca10Na(PO4)7 and Ca10K(PO4)7 are pure phases. The photoluminescence properties of the Ca10M(PO4)7:Eu (M = Li, Na, K) phosphors showed that the self-reduction of Eu3+ to Eu2+ can occur in an air atmosphere. Eu3+ ions can be reduced to Eu2+ ions when doped in Ca10Li(PO4)7, Ca10Na(PO4)7 and Ca10K(PO4)7 crystals, which was detected using photoluminescence spectra. In this work, the bond energy method was used to determine and explain the mechanism of site occupation of Eu entering the host matrix. According to the calculated value of the deviation of bond energy for Eu3+-doped Ca10M(PO4)7 (M = Li, Na, K) crystals, the similar value between and , and , and and can provide the conditions for the self-reduction of Eu3+ in the Ca10M(PO4)7 (M = Li, Na, K) system. Meanwhile, the smaller deviation values of , , and in Ca10Li(PO4)7, Ca10Na(PO4)7, and Ca10K(PO4)7 crystals and in Ca10K(PO4)7 crystals indicated that the preferential sites of Eu ion occupancy in the Ca10M(PO4)7 (M = Li, Na, K) lattices are Li, Na, K and Ca sites. The conclusions obtained from the calculated results of the bond energy method are consistent with the Rietveld refinement and the photoluminescence spectra of Ca10M(PO4)7 (M = Li, Na, K).

A new type of thin and broadband metamaterial absorbers containing patterned magnetic sheet as the middle layer in the tri-layer structure are presented in this article. Those absorbers with more t...

In this letter, a kind of composite radar absorption material consisting of gradient and spiral square resistor frequency selective surface (FSS) and magnetic sheets is designed by HFSS. The use of resistor FSS makes a significant increase of operating bandwidth compared to single magnetic radar absorption materials (mRAMs). Under the condition of normal incident electromagnetic wave, it has remarkable absorptive performance with the reflectivity below $-$ 10 dB with a thin thickness of 2 mm in the range of 6–18 GHz. In addition, the composite mRAMs exhibits high angular stability when the incident angle ranges from 0 ${^\circ}$ to 30 ${^\circ}$ . In order to illustrate the importance of resistors, a comparative experiment of structure with nonresistor FSS is made. Experimental results are compared to numerical simulations. They are in agreement with each other.

To achieve broadband microwave absorption, a three-layer structure is designed and manufactured. It involves a resistive frequency selective surface (FSS) sandwiched between two layers of magnetic sheets. The measurement results reveal that this structure exhibits −13 dB reflectivity in the frequency range of 7.9-18 GHz while the thickness is only 1.7 mm. The reflectivity bandwidth at the level of −10 dB is 11.4 GHz which is much wider than that of magnetic sheets with non-resistive FSS or the magnetic sheets without FSS. The effect of resistive FSS on the performance of the multilayered absorber is discussed in detail. It is concluded that an embedded resistive double loops FSS can result in a secondary resonance peak which obviously broadens the reflectivity bandwidth of the magnetic sheets.

Data presented in this article are related to the research article entitledO2−–V5+charge transfer band, chemical bond parameters and R/O of Eu3+doped Ca(VO3)2and Ca3(VO4)2: A comparable study[ing Li, Yu Pan, Wenjun Wang, Zihao Wen, Xuanxi Leng, Qi Wang, Liqun Zhou, Haibing Xu, Qinghua Xia, Li Liu, Hongping Xian, Xiaoguang Liu]. The data present the fitting results of the broad excitation spectra of Ca(VO3)2:1%Eu and Ca3(VO4)2:1%Eu using the Gaussian model, the O/R values using the experimental PL emission results. The data compares the optimized cell parameters for Ca(VO3)2: 1%Eu and Ca3(VO4)2:1%Eu through the CASTEP geometry optimization with their initial cell parameters.

The design and fabrication of a composite ultrathin magnetic-type radar absorption material (RAM) exhibiting excellent properties of wide bandwidth is demonstrated in this study. RAMs with the range of 2–18 GHz are obtained based on EW (a type of iron carbonyl powder produced by BASF chemical company)-filled silicon rubber, into which an frequency selective surface (FSS) in the form of treble-square loops is embedded. The FSSs contribute to broadening bandwidth of the RAM without almost increasing the thickness. By designing the appropriate unit dimensions of FSS, an optimized operating bandwidth can be obtained. Experimental results are obtained and compared with simulation results in High Frequency Structure Simulator, and they demonstrated that the RAMs embedded with FSSs or resistive FSSs all have good results of broadening the effective frequency band, showing that the proposed RAM can provide a 10-dB reflectivity over the frequency range of 6.8–18 and 3.6–4.4 GHz, which is equivalent to a relative b...

Here in this work, we report the fabrication of a (metal) ion selective surface enhanced Raman scattering (SERS) optrode, the counterpart of an ion selective electrode, for the detection of metal ions in solution. Following our previous work, a layer-by-layer self-assembly strategy was used to fabricate the SERS optrode, followed by modification with an ion chelating reagent, 4-(4-phenylmethanethiol)-2,2′:6′,2′′-terpyridine (PMTTP). The SERS spectrum change after binding with metal ions was used to identify and detect metal ions in solution. Cd2+ in aqueous solution was chosen as a sample analyte. Similar to standard pH measurement, through simple single point known standard solution calibration, a quick (semi-)quantitative analysis of Cd2+ was realized.

To improve the interfacial properties of carbon fiber (CF) reinforced composites, an innovative and simple functionalized strategy has been proposed by grafting 4,4'-oxydianiline (ODA) onto carbon fiber surface using hexachlorocyclophosphazene (HCCP) as a novel coupling agent at mild reaction conditions. The chemical composition of the CF surface was confirmed by X-ray photoelectron spectra (XPS). The surface topography and surface energy of CF were examined by atomic force microscope (AFM) and dynamic contact angle tests (DCA), respectively. The interfacial shear strength (IFSS) of CF reinforced composites was studied by microbond test. The tensile strength of CF was measured by single filament tensile test. After functionalization treatment, the grafted amine groups on the fiber surface enhanced the surface wettability of modified CF and formed strong chemical bonding between fiber and matrix, improving the interfacial adhesion strength of composites. The interfacial shear strength of modified CF reinforced composites increased by 71.2% compared with that of desized CF. The interfacial enhancement mechanism was also discussed in detail. Moreover, the modified CF almost kept the original mechanical properties after functionalization. (C) 2014 Elsevier B.V. All rights reserved.

Hippocampus is needed for both spatial working and reference memories. Here, using a radial eight-arm maze, we examined how the combined demand on these memories influenced CA1 place cell assemblies while reference memories were partially updated. This was contrasted with control tasks requiring only working memory or the update of reference memory. Reference memory update led to the reward-directed place field shifts at newly rewarded arms and to the gradual strengthening of firing in passes between newly rewarded arms but not between those passes that included a familiar-rewarded arm. At the maze center, transient network synchronization periods preferentially replayed trajectories of the next chosen arm in reference memory tasks but the previously visited arm in the working memory task. Hence, reference memory demand was uniquely associated with a gradual, goal novelty-related reorganization of place cell assemblies and with trajectory replay that reflected the animal’s decision of which arm to visit next.

In this letter, we report the fabrication, and measurement of an ultra-broadband polarization-insensitive metamaterial absorber (MA), consisting of three layers. The EW and flaky carbonyl iron powders were used to produce two kinds of silicone rubber matrix magnetic composites for the top and the bottom layer, respectively. The middle layer is frequency selective surface (FSS) in the form of single square loop. The results show that the proposed 2.0 mm thick RAM can provide a 10 -dB reflectivity over the frequency range of 5.35–18 GHz and exhibit polarization-insensitive properties over the whole range of 2–18 GHz. Experimental results were in good agreement with simulated ones.

Selenium (Se) is generally known as an essential micronutrient and antioxidant for humans and animals. Aflatoxin B1 (AFB1) is a frequent contaminant of food and feed, causing immune toxicity and hepatotoxicity. Little has been done about the mechanisms of how Se protects against AFB1-induced immune toxicity. The aim of this present study is to investigate the protective effects of Se against AFB1 and the underlying mechanisms. The primary splenocytes isolated from healthy pigs were stimulated by anti-pig-CD3 monoclonal antibodies and treated by various concentrations of different Se forms and AFB1. The results showed that Se supplementation alleviated the immune toxicity of AFB1 in a dose-dependent manner, as demonstrated by increasing T-cell proliferation and interleukin-2 production. Addition of buthionine sulfoximine abrogated the protective effects of SeMet against AFB1. SeMet enhanced mRNA and protein expression of glutathione peroxidase 1 (GPx1), selenoprotein S (SelS), and thioredoxin reductase 1 without and with AFB1 treatments. Furthermore, knockdown of GPx1 and SelS by GPx1-specific siRNA and SelS-specific siRNA diminished the protective effects of SeMet against AFB1-induced immune toxicity. It is concluded that SeMet diminishes AFB1-induced immune toxicity through increasing antioxidant ability and improving GPx1 and SelS expression in splenocytes. This study suggests that organic selenium may become a promising supplementation to protect humans and animals against the decline in immunity caused by AFB1.

In this paper, a polarization-insensitive wideband tunable metamaterial absorber is designed and fabricated. The equivalent circuit model for the absorber has been proposed to describe its absorption phenomenon. The proposed absorber is constructed by a periodic array of unit, which contains four split semi-circle ring resonators with 90° rotated. The symmetric structure of the unit gives rise to polarization-insensitivity. Furthermore, the field distribution and the circuit model of the absorber are studied to demonstrate its absorption mechanism. Measurement results show that the proposed metamaterial absorber obtains a reflectivity of less than −10 dB covering 2.1–2.5 GHz and 3.1–6.8 GHz with the total thickness of 8.8 mm, and the reflectivity performance covering the spectrum from 3.1 GHz to 6.8 GHz could be adjusted by tuning the bias voltage on the PIN diodes.