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Based on the hole-drilling strain sensing method, a ring Fiber Bragg Grating (FBG) array is proposed to realize comprehensive and convenient measurement of residual stress for homogeneous or inhomogeneous materials. All FBG sensors are arranged tangentially along the edge of the ring. With the ring array around the drilled hole, more detailed information of the residual stress can be obtained such as the location and the degree of inhomogeneity. The tangential arrangement of FBG sensors can achieve comparable measurement results to the radial arrangement but it brings convenience for the drilling process without any overlap upon the hole position. This method promotes the application of the FBG sensors in the residual stress measurement field.

A chirp compensation method of fiber Bragg grating (FBG) is proposed to improve the residual stress measurement accuracy in the hole-drilling method. The effects of the radii of the hole, the distance between the FBG and the hole, the Young’s modulus of the material, and the residual stress on the FBG chirped spectra are analyzed. The relationship between radii of the hole, the distance between the FBG and the hole, the full-width at half maximum (FWHM), and the peak wavelength are established. The feasibility of the method is verified through experiments, which shows that the residual stress measurement error can be reduced by the compensation method.

Fatigue crack growth tests were carried out on the SEN B3 precracked specimens, with dimensions in accordance with ISO 12108 requirements. The specimens were made of martensitic stainless steel, X17CrNi15-2, and some of them were modified by the ceramic coating deposition surface treatment. The effects of ceramic coating, on the fatigue crack growth behaviour of hollow shaft specimens, were experimentally investigated. Fatigue crack growth rates, da/dN, were characterised, using the power law relationship between da/dN (in mm/cycle) and the stress intensity factor range, ΔK (in MPa∙m0.5). The two constants of the correlation are 7.9768 × 10−9 and 2.8107 for the parent material, and those for the coated material are 2.4391 × 10−9 and 3.1990, respectively. Microstructural analyses were carried out on the tested specimens, which shows that the maximum hardness of the ceramic coating is higher than that of substrate by a factor of ~3.2. The dimple fracture dominates the final fracture mechanism for the parent material, and the combination of fatigue, ductile fracture and cleavage dominates the final fracture mechanism for the coated material, based on the SEM analyses. EDS tests’ results reveal that the parent material specimen shows higher levels of C at matrix regions along with Fe- and O-rich regions, compared with the coated material specimen.

Defects can induce drastic changes of the electronic properties of two-dimensional transition metal dichalcogenides and influence their applications. It is still a great challenge to characterize small defects and correlate their structures with properties. Here, we show that tip-enhanced Raman spectroscopy (TERS) can obtain distinctly different Raman features of edge defects in atomically thin MoS2, which allows us to probe their unique electronic properties and identify defect types (e.g., armchair and zigzag edges) in ambient. We observed an edge-induced Raman peak (396 cm−1) activated by the double resonance Raman scattering (DRRS) process and revealed electron–phonon interaction in edges. We further visualize the edge-induced band bending region by using this DRRS peak and electronic transition region using the electron density-sensitive Raman peak at 406 cm−1. The power of TERS demonstrated in MoS2 can also be extended to other 2D materials, which may guide the defect engineering for desired properties. Probing inevitable defects in two- dimensional materials is challenging. Here, the authors tackle this issue by using tip-enhanced Raman spectroscopy (TERS) to obtain distinctly different Raman features of edge defects in atomically thin MoS2, and further probe their unique electronic properties as well as identify the armchair and zigzag edges.

A low‐profile metasurface antenna with circularly polarized radiation and tailored anisotropic reflection is proposed in this letter. The metasurface antenna composed of excitation structure (microstrip line with coupling slot) and a metasurface layer. The metasurface functions for two goals, generating circularly polarized wave for radiation and tailoring reflection phase for scattering, respectively. The overall structure of the metasurface antenna is compact with a dimension of 0.67λ × 0.67λ × 0.05λ at 5 GHz. Numerical and measured results confirm that the metasurface antenna exhibits 11.1% −10 dB S11 bandwidth from 4.68 to 5.23 GHz, 10.8% 3 dB axial ratio bandwidth from 4.782 to 5.37 GHz and a maximum gain of 6.83 dBic. Besides, the metasurface antenna achieves anti‐phase reflection under orthogonal polarized incident waves at around 5 GHz. To demonstrate a potential application, 16 identical metasurface antennas are put in a 4 × 4 array. The metasurface antenna array achieves directive circularly polarized radiation with a maximum gain of 15 dBic. On the other hand, when under normal illumination, the scattering field of metasurface antenna array is redistributed due to phase cancelation, so that the backward radar cross section of the array is significantly reduced, which is applicable for military platform.

A facile oxalate co-precipitation method combined with solid-state sintering is used to synthesize layered LiNi0.6Co0.2Mn0.2O2 (NCM-622) as a low-cost cathode material for lithium ion batteries. Homogeneous Ni-Co-Mn oxalate precursors were obtained by adding oxalic acid into mixed metal acetates without the need of rigorous control of co-precipitation parameters. The effects of sintering temperature on the morphology, structure and electrochemical properties of the synthesized NCM-622 are studied. An intermediate sintering temperature of 850 °C is found to favor the integrity of the layered structure by compromising the solid-state reaction and Li loss, leading to a low degree of cation mixing. The as-synthesized NCM-622 delivers a capacity of 152 mA h g−1 after 100 cycles at 1 C (93.2% retention), and shows excellent rate capability with 76.8 mA h g−1 at 10 C, which is competitive to the materials prepared by the mainstream hydroxide co-precipitation method. Moreover, a solution-based surface modification was employed to further improve the cathode through self-adsorption of Al(OH)3 using Al2(SO4)3 precursor in order to form a Al2O3 coating. The facial surface modification has significantly improved the performance of NCM-622 under normal and high voltage conditions.

Lu(OH)CO3:Ln3+/LuBO3:Ln3+ (Ln = Eu, Tb) nanospheres have been synthesized by the soft chemistry route. This synthesis process does not require the addition of any organic solvents and surfactant. The whole process consists of homogeneous precipitation and hydrothermal process. First, uniform spherical Lu(OH)CO3:Ln3+ (Ln = Eu, Tb) nanoparticles with the sizes of 70 nm were obtained by the classic urea-based homogeneous precipitation. Then, with the above Lu(OH)CO3:Ln3+ (Ln = Eu, Tb) nanosphere as the precursor, the composites of Lu(OH)CO3:Ln3+/LuBO3:Ln3+ (Ln = Eu, Tb) nanospheres formed by the simple hydrothermal process. The phases, morphologies, as well as the luminescence properties of as-prepared samples were characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and photoluminescence. Under a short wavelength excitation, the down-conversion Eu3+ and Tb3+-doped LuBO3 samples were investigated and explained.

The vast development of nanofabrication has spurred recent progress for the manipulation of light down to a region much smaller than the wavelength. Metallic plasmonic array structures are demonstrated to be the most powerful platform to realize controllable light-matter interactions and have found wide applications due to their rich and tunable optical performance through the morphology and parameter engineering. Here, various light-management mechanisms that may exist on metallic plasmonic array structures are described. Then, the typical techniques for fabrication of metallic plasmonic arrays are summarized. Next, some recent applications of plasmonic arrays are reviewed, including plasmonic sensing, surface-enhanced spectroscopies, plasmonic nanolasing, and perfect light absorption. Lastly, the existing challenges and perspectives for metallic plasmonic arrays are discussed. The aim is to provide guidance for future development of metallic plasmonic array structures.

Low size-of-source effect (SSE) infrared optical system design and experimental validation are critically involved. SSE is commonly explored in infrared radiation measurements. The main causes of SSE are the diffraction of the field aperture, the reflection of optical components and objective aberrations. The optical path design and the internal components scattering have an important influence on SSE. Reflective optical system is commonly used in infrared radiation measurements with high temperature region and wide wavelength range, which can eliminate chromatic aberration and reduce coma. A reflective infrared optical system is designed and built based on the high-temperature Fourier transform infrared (FTIR) spectrometer infrared radiation measurement facility at NIM. The ambient scattered radiation and the thermal effect of optical components are controlled via the water-cooled scattered radiation shielding bin and limitation apertures. Experimental validation of the SSE characteristics of the FTIR infrared optical system is carried out via the uniform blackbody radiation source at 500 °C and various sized apertures using the direct measurement method. The corresponding calculation model will be described in the paper. SSE on 3.9 μm is measured via the direct measurement method by using a standard reference blackbody with good temperature uniformity as the radiation source. The effect of reflection is reduced via the high emissivity coating on the apertures. The results show that the effect of the SSE on the FTIR measurement facility at the wavelength of 3.9 μm is less than 2×10-4. Details and results of the infrared optical system SSE measurement will be reported in the paper. All measurements can be traceable to the National Standards of P. R. China.

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive technique with molecular specificity, making it an ideal analytical tool in various fields. However, the breadth of practical applications of SERS has been severely limited because it is still a great challenge to achieve simultaneously a high sensitivity and a high reproducibility. Herein, we report a highly controllable method to fabricate periodic bowtie SERS substrates with a narrow nanogap, high SERS enhancement, and good uniformity over a large area. The periodic bowtie template is first fabricated over a gold film by holographic lithography (HL), followed by Au deposition to obtain a conductive plasmonic bowtie array. The gap size is then narrowed down by pulsed electrodeposition of Ag simultaneously monitored in situ by electrochemical dark field spectroscopy. Thus, we are able to observe the most sensitive change in the scattering spectra when the gap is just about to merge and obtain uniform SERS substrates with a gap size down to around 5 nm. The average enhancement factor of 5 × 107 to 1 × 108 is obtained, which is 50 times larger than that from Au nanoparticle-assembled substrates and 140 times larger than that from commercial Klarite chips. This substrate offers a promising opportunity for SERS practical applications.

In view of the potential application of NIR luminescence in biology, a series of four new 3,5-Heptanedione (β-diketonate) ytterbium complexes, e.g. [Yb(L)3(H2O)2] (1), [Yb(L)3(2,2′-bpy)] (2), [Yb(L)3(dpq)] (3) and [Yb(L)3(dppz)] (4) have been designed and isolated. Crystal structures analysis show that all complexes 1–4 exhibit the similar mononuclear structure, in which the central Yb3+ ion is eight-coordinated forming the square-anti-prismatic geometry. NIR luminescence of all complexes 1–4 shows strong characteristic emission of Yb3+ ions. To improve the mechanical and thermal stability, complex 1 was further doped into poly-(methyl methacrylate) (PMMA) for preparing a thin film (1@PMMA). Their thermal stability and NIR luminescence were essentially enhanced in contrast to that for complex 1. This NIR luminescent thin film may be of potential applications in biological dictation and luminescent probe.

In this study, bamboo flour (BF) was chemically modified using alkyl ketene dimer (AKD) or alkali treatment for the preparation of high-density polyethylene/bamboo flour (HDPE/BF) composites with or without compatibilizer maleic anhydride grafted high-density polyethylene (HDPE-g-MAH). The modified BF was characterized by Fourier transformation infrared (FTIR) spectroscopy and contact angle measurement, and the mechanical properties, morphology and water resistance of the HDPE/BF composites were investigated and compared. The results show that highly hydrophobic BF can be obtained by a simple procedure using a common paper sizing agent AKD. AKD can react with the hydroxyl groups in cellulose to form β-keto ester. The combination of AKD treatment and addition of HDPE-g-MAH is more effective in improving the mechanical properties of HDPE/BF composites than using them alone. The impact strength, flexural strength and modulus of HDPE/A-BF/MAH composite are increased by 100.0%, 197.1% and 61.8% compared with that of HDPE/U-BF composites, and the water absorption and thickness swelling are decreased by 87.7% and 87.4% after immersion in water for one week, respectively. These results indicate that HDPE/BF composites with good mechanical properties and high water resistance can be obtained by AKD treatment.

Integrated blackbody is a blackbody radiation source with the emissivity approximate to 1, which is coupled of materials with different infrared emissivity as the cavity wall and the cavity bottom. The integrated blackbody theory is the theoretical basis of materials infrared spectral emissivity measurement device at ultra-high temperature developed by National Institute of Metrology, China (NIM). Infrared emissivity is the most important factor for evaluating the infrared radiation characteristics of integrated blackbody. Based on Monte Carlo simulation, infrared emissivity of the integrated blackbody coupled of different high emissivity materials and infrared emissivity of the integrated blackbody coupled of low emissivity material and high emissivity material are calculated theoretically in the near infrared wavelength band at room temperature and high temperature environment. The simulation results show that, the infrared emissivity of the integrated blackbody coupled of different high emissivity materials can reach 0.998 and the infrared emissivity of the integrated blackbody coupled of low emissivity material and high emissivity material can reach 0.988. The above simulation results of integrated blackbody infrared emissivity have reached the requirements of industrial blackbody radiation source. The simulation results are verified based on the method of blackbody infrared emissivity measurement by integrating sphere reflectometer at room temperature environment at wavelength of 0.633 μm. Measurement results on multiple wavelengths show that the deviation between the integrated blackbody infrared emissivity simulation results and the measurement results is less than 0.3 %.

Polypyrrole (PPy) is a highly conductive polymer and promising pseudocapacitive material for energy storage. However, the poor stability of PPy based supercapacitors (SCs) limits their applications. Here we demonstrate a facile dipping process to uniformly grow 4-butylbenzenesulfonate modified PPy film on a filter paper substrate. The flexible and free-standing PPy paper electrode demonstrated excellent cycling stability with capacitance retention of ~84.8% after 200,000 cycles. We believe that the 4-butylbenzenesulfonate modification could increase the order degree of PPy via layer-by-layer stacked α-α coupled chains, leading to a robust structure under the charging and discharging progress. This work pushes the cycling limitation of PPy based SCs and realizes their potentials for practical applications.

A series of four β-diketone mononuclear Dy(iii) complexes, namely Dy(Hthd)3(MeOH)·2,5-Py (1), Dy(Hthd)3(Tppo) (2), Dy(Hthd)3(PyNO) (3), and Dy(Hthd)3(4-PyNO) (4) (Hthd = 2,2,6,6-tetramethyl-3,5-heptanedione, 2,5-Py = 2,5-pyridine, Tppo = triphenylphosphine oxide, PyNO = pyridine N-oxide, 4-PyNO = 4-methylpyridine N-oxide), have been isolated by reactions of Hthd, DyCl3·6H2O and an auxiliary ligand. X-ray crystallographic analysis revealed that complexes 1-4 are all seven-coordinated mononuclear structures with C2v or C3v local symmetry. The magnetic measurements of complexes 1-4 revealed their field-induced single-ion magnet (SIM) behavior, due to mixed low-lying states. The crystal field parameters and orientations of the magnetic easy axes were obtained from simulations of the DC magnetic data and an electrostatic model calculation. The magneto-structural correlation of seven-coordinated Dy(iii) SIMs with low-symmetry coordination environments was further discussed.

Tip-enhanced Raman spectroscopy (TERS), known as nanospectroscopy, has received increasing interest as it can provide nanometer spatial resolution and chemical fingerprint information of samples simultaneously. Since Ag tips are well accepted to show a higher TERS enhancement than that of gold tips, there is an urgent quest for Ag TERS tips with a high enhancement, long lifetime, and high reproducibility, especially for atomic force microscopy (AFM)-based TERS. Herein, we developed an electrodeposition method to fabricate Ag-coated AFM TERS tips in a highly controllable and reproducible way. We investigated the influence of the electrodeposition potential and time on the morphology and radius of the tip. The radii of Ag-coated AFM tips can be rationally controlled at a few to hundreds nanometers, which allows us to systematically study the dependence of the TERS enhancement on the tip radius. The Ag-coated AFM tips show the highest TERS enhancement under 632.8 nm laser excitation and a broad localized surface plasmon resonance (LSPR) response when coupled to a Au substrate. The tips exhibit a lifetime of 13 days, which is particularly important for applications that need a long measuring time.

Accurate measurement of the material surface temperature plays a vital role in many scientific and technological advances. With the application of the active infrared laser radiation thermometry, the surface temperature can be obtained independently of the target emissivity. This method has been developed gradually, but there is still lacking of the experimental result about low emissivity surfaces, and the determination of the system core parameter has not been sufficiently discussed. Therefore, a new active infrared laser radiation thermometry system is reported in this paper. The temperature change radiance signals emitted from the target surface at the same frequency as the heating laser are accurately screened and collected by using a lock-in amplifier, and the calibration method of the instrument constant is discussed. The experimental results show that, for high emissivity sample, in the range of 873–1173 K, the relative deviation between the temperature measurement results of the experimental device and the reference value is within 0.5%. For the low emissivity sample, also in the range of 873–1173 K the relative deviation between the measurement results of the experimental device and the reference temperature is within 0.8%, and the average absolute deviation is 3.3 K. The measurement accuracy is improved and compared with previous literature.

In this work, commercial LiCoO 2 is modified with a glassy B 2 O 3 by solution mixing with H 3 BO 3 followed by post-calcination in order to enhance its high-voltage electrochemical performance. The glassy B 2 O 3 coating/additive is believed to serve as an effective physiochemical buffer and protection between LiCoO 2 and liquid electrolyte, which can suppress the high-voltage induced electrolyte decomposition and active material dissolution. During the early cycling and due to the electrochemical force, the as-coated B 2 O 3 glasses which have 3D open frameworks tend to accommodate some mobile Li + and form a more chemically-resistant and ion-conductive lithium boron oxide (LBO) interphase as a major component of the solid electrolyte interphase (SEI), which consequently enables much easier Li + diffusion/transfer at the solid-liquid interfaces upon further cycling. Due to the synergetic effects of B 2 O 3 coating/modification, the high-voltage capacity and energy density of the B 2 O 3 -modified LiCoO 2 cathode are promisingly improved by 35% and 30% after 100 cycles at 1 C within 3.0–4.5 V vs. Li/Li + . Meanwhile, the high-rate performance of the B 2 O 3 -modified electrode is even more greatly improved, showing a capacity of 105 mAh g −1 at 10 C while the bare electrode has dropped to no more than 30 mAh g −1 under this rate condition.

With the increasing demand for high energy density in portable-device Li-ion batteries (LIBs), efforts are devoted to increase and stabilize the capacity of LiCoO2 at high operation voltages. Herein, we report a low-cost and eco-friendly wet-chemical method to coat Al2O3 on LiCoO2, using only aluminium sulphate and water as source materials. A nanoscale oxide layer is coated on the surface of LiCoO2 particles through hydrogen-bonding assisted adsorption of the hydrolysed Al(OH)3 nanoparticles. The as-proposed Al2O3-coating provides excellent physico-chemical protection and kinetically-favourable interfaces for the LiCoO2 electrode, resulting in remarkable improvements of the electrode's cycling stability and rate capability when tested at high cutoff voltages up to 4.7 V (vs. Li/Li+). The synergetic effects of the oxide coating, e.g. alleviated electrolyte decomposition and reduced generation of irreversible solid electrolyte interphase (SEI) constituents (LiF/Li2CO3 and organics), are attributed to the improvements. At the cutoff voltage of 4.5 V, the modified LiCoO2 electrode in this work exhibits excellent cycling stability (147 mA h g−1, 82.6% retention after 500 cycles at 1C) and competitive rate capability (130 mA h g−1 at 10C), which are some of the best results reported so far. The outstanding high-voltage electrode performance and the simple and scalable coating approach show great promise of LiCoO2 cathodes in future high-energy and high-power LIBs.

A white-light-emitting LnCP is effectively applied to the detection of Ag+ and Mn2+ ions with high selectivity and sensitivity via luminescence-colour change.

The spectral responsivity of Fourier Transform Infrared Spectrometer (FTIR) measurement system of high temperature blackbody infrared radiation characteristics is calibrated via ThermoGage HT9500 high temperature reference blackbody furnace from National Institute of Metrology, China (NIM). A calculation model of the spectral responsivity calibration of FTIR measurement system is established. The infrared spectrum of the blackbody radiation source is measured in the temperature range from 1273 K and 1973 K on the wavelength range from 1 μm to 14 μm. Calibration is carried out within the temperature range from 1373 K to 1873 K on the wavelength range between 1 μm and 13 μm. The infrared spectral radiation characteristics of ThermoGage HT9500 high temperature reference blackbody furnace are represented. The results indicated that the method of piecewise linear calibration was practicable. The measured infrared spectrum in the temperature range from 1373 K to 1873 K on the wavelength range between 1 μm and 13 μm was compared with the calculation which showed the signal divergence less than 1%. And the calculated temperature obtained by inverse calculation in this temperature region was compared with the actual temperature which showed the temperature divergence less than 0.45%.

Developing multi-selective luminescence sensing technology to differentiate serial compounds is very important but challenging. White-light-emitting decoding sensing based on lanthanide metal-organic frameworks (Ln-MOFs) is a promising candidate for multi-selective luminescence sensing application. In this work, three isomorphic Ln-MOFs based on H3dcpcpt (3-(3,5-dicarboxylphenyl)-5-(4-carboxylphenl)-1H-1,2,4-triazole) ligand, exhibiting red, blue, and green emission, respectively, have been synthesized by solvothermal reactions. The isostructural mixed Eu/Gd/Tb-dcpcpt is fabricated via the in-situ doping of different Ln3+ ions into the host framework, which can emit white light upon the excitation at 320 nm. It is noteworthy that this white-light-emitting complex could serve as a convenient luminescent platform for distinguishing eight frequently-used antibiotics: five through luminescence-color-changing processes (tetracycline hydrochloride, yellow, nitrofurazone, orange, nitrofurantoin, orange, sulfadiazine, blue, carbamazepine, blue) and three through luminescence quenching processes (metronidazole, dimetridazole, and ornidazole). Moreover, a novel method, 3D decoding map, has been proposed to realize multi-selective luminescence sensing applications. This triple-readout map features unique characteristics on luminescence color and mechanism. The mechanism has been systematically interpreted on the basis of the structural analysis, energy transfer and allocation process, and peak fitting analysis for photoluminescence spectra. This approach presents a promising strategy to explore luminescent platforms capable of effectively sensing serial compounds.

The introduction of oxygen vacancy for transition metal oxide is an effective method to tune their conductivity. Here, microwave combustion method is used to quickly synthesize reduced metal oxides and graphene hybrid composite in several minutes. Among these as-synthesized composites, the reduced orthorhombic Nb2O5 and graphene oxide (rNb2O5/rGO) composite demonstrates great electrochemical performance with a reversible specific capacity of 726.2 C g−1 at 2 mV s−1 in organic electrolyte as well as a good capacity retention of 87% after 3000 cycles at 10 A g−1. It is believed that this strategy can be a common route to quickly produce oxygen vacancy in oxides and satisfy much more application requirements even for the possibility of industrialization.

Thermopower is a key parameter for thermoelectric (TE) materials. Compared to bulk materials, thermopower determination for TE films is challenging especially for those grown on electrically conductive substrates. This work demonstrates the feasibility of the on-substrate thermopower measurement for TE films by the unique potential-Seebeck microprobe (PSM). Thermopower measurements were conducted on the electroplated Bi 2 Te 3 films with different thicknesses prepared on Au-coated Si and quartz substrates in order to reveal the impact of the film thickness and substrate on the measurement accuracy. It is found that the thermopower ( S m ) measured on the Bi 2 Te 3 film grown on Si/Au substrates tends to deviate significantly from the real value if the thickness is smaller than 12 μm. Above 12 μm, no thickness dependence was observed and reliable S m can be obtained for the Bi 2 Te 3 films. Results on quartz/Au substrates show similar thickness dependence for S m , but the derived values are much lower than those obtained on Si/Au substrates. Finite element method (FEM) simulations are performed to interpret the measurement discrepancy as well as the impact of the film thickness and substrate on the thermopower measurement by investigating the detailed temperature and potential profiles in the samples.

To compare the influence of Al2O3 and TiO2 on the sintering behavior of partial reaction bonding silicon nitride (RBSN) and post densification behavior, different amounts of Al2O3 or TiO2 have been added into Si-Si3N4-Y2O3 system. The results indicated that a high amount of Al2O3 addition inhibited the reaction bonding process, a lower nitridation degree was obtained, while TiO2 has limited influence on nitridation, only slightly decreased nitration degree with increasing TiO2 addition. After post sintered at 1800 °C, a density ranging from 2.31 to 3.09g/cm3 were obtained with additions of Al2O3 and TiO2, much larger than the one without them. The linear shrinkage of post-sintered samples was strongly promoted with high Al2O3 content, but it was irrelevant with the amount of TiO2. The highest bending strength of 523MPa can be obtained with addition of 6wt% Al2O3. TiO2 transformed into TiN which located at grain boundary interfaces, restraining the grain growth of β-Si3N4 and leading to an inferior flexural strength after post sintered at 1800 °C.

While vanadium oxides have many attractive pseudocapacitive features for energy storage, their applications are severely limited by the poor electronic conductivity and low specific surface area. To overcome these limitations, a scalable, free-standing film electrode composed of intertwined V2O5 nanowires and carbon nanotubes (CNTs) using a blade coating process has been prepared. The unique architecture of this hybrid electrode greatly facilitates electronic transport along CNTs while maintaining rapid ion diffusion within V2O5 nanowires and fast electron transfer across the V2O5/CNTs interfaces. When tested in a neutral aqueous electrolyte, this hybrid film electrode demonstrates a volumetric capacitance of ≈460 F cm−3. Moreover, a symmetric capacitor based on two identical film electrodes displays a wide operation voltage window of 1.6 V, delivering a volumetric energy density as high as 41 Wh L−1.

The sheet beam gun (SBG) is operated at high temperature, and thermal expansion could induce huge electron beam degeneration. The previous SBG design, which did not take account of thermal expansion, obtained bad transportation performance. Experimental measurement showed that the distance variation between a cathode and an anode was larger than 0.42 mm, which could hugely degenerate beam performance. A new inner support rod with grooves was employed in this paper, and the heat power was reduced from 27 to 15.5 W, while the distance variation was reduced to 0.29 mm. The new SBG with adjustment according to the thermal expansion was fabricated and tested. The transportation rate after anode tunnel was enhanced to 98%, and the total transportation rate of sheet beam traveling wave tube with a period permanent magnet focusing structure was about 90%.

Reactions of LnCl3·6H2O (Ln = La, Ce, Pr, Nd, Gd and Lu), L-dibenzoyl tartaric acid (L-DBTA) and triethylamine in a methanol–water solution afford four complexes 1a–4a with 1D ladder chain structures, e.g. {[Ln2(L-DBTA)3(CH3OH)x(H2O)y]·zH2O}n (x = 3 or 4, y = 3 or 4, z = 2 or 5; Ln = La (1a), Ce (2a), Pr (3a) and Nd (4a)) and two complexes 5 and 6 with 1D linear chain structures, e.g. {Et3NH[Ln(L-DBTA)2(CH3OH)2(H2O)2]·2H2O}n (Ln = Gd (5) and Lu (6)). Accidentally, an in situ irreversible SCSC transformation from the kinetically stabilized 1D ladder chain structures of 1a–4a to thermodynamically stabilized 1D linear chain structures of 1–4 was observed, which was seldom reported for lanthanide coordination polymers. The coordination stability around a lanthanide cation was investigated to expatiate on the irreversible SCSC transformation. The solid-state NIR luminescence for complexes 3a, 3, 4a and 4 was also studied.

Delicate control of the surface plasmon resonance (SPR) line shapes is crucial for the development of nanoplasmonics with dedicated applications. In this paper, we develop a method to fabricate large-scale periodic structures with significantly different plasmonic properties by the holographic lithography method. We show that SPR line shapes can be controllably engineered from a broad superradiant line shape to an asymmetrical Fano-type resonance, as well as an ultranarrow subradiant mode, which are clearly correlated with the structural parameter (morphology) of the fabricated structures. The wavelength of the SPR band can be tuned from the visible to near-infrared region by changing the incident angle. The nanostructures fabricated by the present method show a clear correlation between the morphology of plasmonic structures and SPR line shapes, which can serve as an efficient platform for engineering SPR line shapes for specific applications. Most importantly, the capability to produce structures of lar...

SA335-P92 steel is a kind of heat-resistant steel with martensitic lath as matrix and multi alloy composite strengthening, which has excellent high temperature performance. It is used for high temperature components of high parameter units in China for nearly 20 years. Many research institutions have done a lot of research on the properties and characteristics of high temperature aging and creep durability in the laboratory, but there are few researches on the micro-characteristics and properties of P92 steel after long-term service. In this paper, the studies are carried on the P92 steel of high temperature reheat steam pipeline taken from the first group of ultra-supercritical units in China. The microstructure characteristics and properties of the material are systematically studied by means of test methods such as micro metallography, scanning electron microscopy, EDS and mechanical properties. It is concluded that although the P92 steel after long-term service still remains the microstructure of martensitic lath, but the toughness greatly reduces caused by large amounts of large scale precipitates at the original austenite grain boundaries and lath boundaries.

The Fourier-Transform infrared (FTIR) spectrometer is a commonly used instrument in infrared radiation measurements. An infrared spectral emissivity measurement facility using a deuterated tri-glycine sulfate (DTGS) detector has been set up at the National Institute of Metrology, China (NIM). The linearity of the spectral responsivity is one of the main uncertainty contributions in spectral-emissivity measurement, performed over a wide spectral radiance range (0–30,000 W/(m2·sr·μm)). Using the flux superposition method, a double-aperture method, where the apertures are positioned precisely by a cage structure, has been used to measure the linearity of the FTIR measurement system, a sub-system of the infrared spectral emissivity measurement facility, developed at NIM. The drift characteristics of the blackbody radiation sources and the FTIR measurement system during a typical linearity measurement have been investigated. Drifts of the blackbody sources are reduced by integration of the spectrum. The quasi-linear drifts of the FTIR measurement system are corrected by inverting the measurement sequence of the apertures. Moreover, corrections for the effects of aperture imperfections on the linearity measurement have been quantified experimentally. Measurements are reported for blackbody radiation sources in the temperature range (473–1273 K), with detection at the wavelengths 3.9 μm and 10.6 μm, respectively.

The cylindrical shell is a basic structure in transportation of dangerous goods, hydrogen storage, public safety, aerospace industries, nuclear and power engineering. The dynamic burst pressure of cylindrical shells is crucial to personal safety, environmental pollution and property damage. Based on average shear stress yield (ASSY) criterion, a novel equation is developed to predict the dynamic burst pressure of cylindrical shells. The ASSY criterion is a weighted average of the maximum shear stress and octahedral shear stress. Firstly, the non-uniform impact load is reduced to a parabolic load acting on the inner wall of cylindrical shells. The width of load is the same as the outer diameter of the cylindrical shell. And then, ASSY criterion is adopted to predict the dynamic burst pressure of cylindrical shells for the first time. In the end, the accuracy of our method is validated by comparing with the finite element method (FEM) under different pulse duration. The results indicate that our method can accurately predict the dynamic burst pressure of cylindrical shells under a non-uniform impact load. In addition, the ASSY criterion can be extended to solving dynamic problems with a high precision. Finally, our method can be used as a benchmark for approximate or numerical solutions. It is beneficial to assess the safety and integrity of cylindrical shells under a non-uniform impact load.

In order to explore the cause of cracking of the main steam pipe of an ultra-supercritical unit, A series of corresponding physical and chemical tests for crack failure pipelines. Including chemical composition analysis, room temperature tensile test, high temperature tensile test, impact test, bending test of HAZ(Heat Affected Zone)and base metal, it’s also including metallographic observation and section scanning electron microscopy analysis of crack tip, overall force analysis of pipeline, etc. The results show: Failure crack has obvious characteristics of crack type IV. for example, a large number of creep holes appear in the fine-grained region of the HAZ, Creep holes accumulate, grow up, and form microcracks. In addition, the stress analysis shows that the outer arc side of the pipe is subjected to large tensile stress. In conclusion, the pipe cracking failure is caused by the combination of tensile stress and type IV crack.

Ultrathin MoSe 2 /graphene hybrids have been successfully synthesized through a facile ionic liquid-assisted hydrothermal approach. The resultant hybrids are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It is revealed that the MoSe 2 nanosheets in the hybrids exhibit a graphene-like few-layered structural characteristic of 2–3 layers and are well dispersed and anchored on the large flexible graphene sheets. When evaluated as an anode for LIBs, the obtained MoSe 2 /graphene hybrid electrode demonstrates preferable electrochemical performances with high reversible lithium-storage capacity of ∼1100 mAh g −1 , superior cyclic stability and excellent rate capability. The extraordinary electrochemical properties can be ascribed to the novel hybrid structures composed of ultrathin few-layered MoSe 2 nanosheets and highly conductive graphene as well as the resultant maximized synergistic effect between MoSe 2 and graphene.

A new flash boiling spray model whose atomization criterion based on the void fraction and superheat while evaporation model based on the dual-zone method is established to simulate the flashing sprays. The model function is implemented in KIVA program. Flash boiling spray model predicts spray penetration and spray cone angle and its development trend, in good agreement with the experimental results. The model has a good capability in simulating flash sprays at low superheat conditions, which breakup is controlled by void fraction, as well as high superheat transition process. It can also predict flare flashing sprays to some extent at higher superheat conditions.

A free-standing fluorinated graphene (F-graphene) was fabricated by the simple liquid exfoliation of a fluorinated graphite (F-graphite) in a 2-propanol/water mixture, and was used as the cathode material of primary lithium ion batteries. As-prepared F-graphene as a very high fluorine content (49.7 at%), and an amorphous-like two-dimensional nanostructure. These features facilitate the rapid diffusion of lithium ions during discharging. The F-graphene exhibits better electrochemical performance, especially, a higher specific power density than the F-graphite. [New Carbon Materials 2015, 30(1): 79–85]

Two types of sixteen complexes 1–16, namely, {[Ln(TFBDC)1.5(H2O)]·2H2O}n [Ln = Pr (1) and Nd (2)] and {[Ln(TFBDC)1.5(H2O)2]·H2O}n [Ln = Ce (3), Pr (4), Nd (5), Sm (6), Eu (7), Gd (8), Tb (9), Dy (10), Ho (11), Er (12), Yb (13) and Lu (14)], {[Dy0.281Eu0.719(TFBDC)1.5(H2O)2]·H2O}n (15) and {[Gd0.871Eu0.103Tb0.026(TFBDC)1.5(H2O)2]·H2O}n (16), were isolated by the reaction of LnCl3·6H2O with 2,3,5,6-tetrafluoroterephthalic acid (H2TFBDC). X-ray crystallographic analysis revealed that 1 and 2 exhibit 3D network structures and complexes 3–14 feature 2D network structures formed via three different coordination modes of the ligand. Luminescence spectra revealed that these complexes exhibit broad-spectrum luminescence from the visible to the near-infrared (NIR) region. Unexpectedly, complex 1 exhibits a unique NIR luminescence pattern and the longest lifetime among reported molecular praseodymium complexes. White-light emission was realized via three approaches using the single-component complex 6 (Sm), the two-component complex 15 (Eu and Dy) and the three-component complex 16 (Eu, Tb and Gd). Complex 9 exhibits high sensitivity and selectivity in its luminescence response to benzaldehyde, which provides a promising luminescent sensor for the detection of benzaldehyde.

Flower-like MoS 2 microspheres were successfully synthesized via a facile hydrothermal route followed by annealing treatment using biopolymer (sodium alginate, SA) as an additive. The experimental results indicated that the MoS 2 products were of hexagonal phases and had a hierarchical flower-like morphology, which were constructed with MoS 2 nanosheets. A probable SA-induced assembly process was presented to account for the formation of the flower-like microspheres. Additionally, as an electrode material for supercapacitor, this MoS 2 microsphere delivered a high specific capacitance at a large current density with good cycle ability.

Porous SnO2 nanospheres with uniform morphologies and sizes were fabricated via a biopolymer (sodium alginate, SA)-assisted hydrothermal route. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high solution TEM (HRTEM), nitrogen adsorption–desorption, Fourier transform infrared (FT-IR) spectroscopy and UV–vis absorption spectroscopy. The obtained tetragonal SnO2 nanospheres were characteristic of hierarchical mesoporous structures with good crystallinity and high purity. Moreover, it was found that the porous SnO2 nanospheres were composed of numerous tiny nanocrystals as building blocks and the SA played a key role in formation of the porous nanospheres with uniform morphologies and sizes. Additionally, the photocatalytic activity of the obtained porous SnO2 nanospheres under sunlight irradiation was also evaluated by degradation of Rhodamine B (RhB).

MoO3was synthesized by thermal decomposition of ammonium molybdate. The structure and surface morphology of the as-prepared MoO3was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The supercapacitive behaviour of MoO3in 1 mol L-1KCl electrolyte was studied by cyclic voltammetry (CV), galvanostatic charge-discharge cycling (CD). The affect of thermal decomposition temperature on the capacitive behaviour of MoO3was also discussed here. The results indicate that MoO3show good capacitive behaviour with a specific capacitance of 148.9 F g-1at 0.7 A g-1. Thermal decomposition temperature has an important influence on the capacitive behaviour and crystallization of MoO3.

In this study, we present a broadband nano-photodetector based on single-layer graphene (SLG)-carbon nanotube thin film (CNTF) Schottky junction. It was found that the as-fabricated device exhibited obvious sensitivity to a wide range of illumination, with peak sensitivity at 600 and 920 nm. In addition, the SLG-CNTF device had a fast response speed (τr = 68 μs, τf = 78 μs) and good reproducibility in a wide range of switching frequencies (50–5400 Hz). The on-off ratio, responsivity, and detectivity of the device were estimated to be 1 × 102, 209 mAW−1 and 4.87 × 1010 cm Hz1/2 W−1, respectively. What is more, other device parameters including linear performance θ and linear dynamic range (LDR) were calculated to be 0.99 and 58.8 dB, respectively, which were relatively better than other carbon nanotube based devices. The totality of the above study signifies that the present SLG-CNTF Schottky junction broadband nano-photodetector may have promising application in future nano-optoelectronic devices and systems.

Selecting four types of sand with different ranges of particle diameter, the strength tests of sand solidification with microbial cement are carried out in this paper. With experimental conditions in this paper, most of the strengths of solidified sand with microbial cement are in the range of 1.2∼2.7MPa. Particle gradation is an important factor that affects the solidification of microbial cement. And the perfusion method is more suitable for the sand with appropriate porosity and good connectivity which is easy to be perfused, but not for clay and sludge. The stirring molding method is more suitable for clay and sludge which have much content of fine powder. The strength of solidified sand is related to the direction of perfusion; and the strength of its upper part is higher than that of the lower part. Compared with other solidification materials, the solidified sand with microbial cement has no obvious advantages, due to its low strength, many limitations as well as complex construction technology; dnd its application field needs further study and exploration.

Liquid desiccant air-conditioning system (LDAS) is a novel air-conditioner with good energy saving potential. Electrodialysis (ED) regeneration is a novel regeneration method for LDAS, which has a higher performance than the conventional thermal regeneration method. In this paper, an experimental setup was developed to study the performance of ED regenerator for liquid desiccant. Based on experimental results, the current utilization of ED regenerator and the mass transfer rate of desiccant solution on unit area of anion-exchange membrane were experimentally obtained. The effects of different flow rates of regenerated and diluted desiccant solution on the current utilization and the mass transfer rate on unit area of anion-exchange membrane are studied. The results show that the largest mass concentration difference between regenerated desiccant solution at the entrance and the exit of the ED regenerator is 0.011%, and the largest mass concentration difference between regenerated desiccant solution at start and end of the experiment is 0.03%. Meanwhile, the largest current utilization of the experimental system of ED regenerator is 55%. Moreover, the current utilization and the mass flow rate of regenerated desiccant solution will increase with the flow rate of desiccant solution.