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Silicon carbide (SiC) nanostructure is a type of promising field emitter due to high breakdown field strength, high thermal conductivity, low electron affinity, and high electron mobility. However, the fabrication of the SiC nanotips array is difficult due to its chemical inertness. Here we report a simple, industry-familiar reactive ion etching to fabricate well-aligned, vertically orientated SiC nanoarrays on 4H-SiC wafers. The as-synthesized nanoarrays had tapered base angles &gt, 60°, and were vertically oriented with a high packing density &gt, 107 mm−2 and high-aspect ratios of approximately 35. As a result of its high geometry uniformity—5% length variation and 10% diameter variation, the field emitter array showed typical turn-on fields of 4.3 V μm−1 and a high field-enhancement factor of ~1260. The 8 h current emission stability displayed a mean current fluctuation of 1.9 ± 1%, revealing excellent current emission stability. The as-synthesized emitters demonstrate competitive emission performance that highlights their potential in a variety of vacuum electronics applications. This study provides a new route to realizing scalable field electron emitter production.

A four-fold interpenetrated Zn(II)-based coordination polymer with the chemical formula of {[Zn2(L)2(bdc)]·(H2O)2·DMF}n (1) was synthesized by solvent method using terephthalic acid (H2bdc) and N1,N1,N4,N4-tetrakis(4-(1H-imidazol-1-yl)phenyl)benzene-1,4-diamine (L) as the mixed ligands. The as-prepared complex 1 was measured via the elemental analysis and single crystal X-ray diffraction. Furthermore, due to its strong intense emission, complex 1 could be applied as luminescent sensor to sensitively detect 2,4,6-trinitrophenol (TNP), which has the characteristics of high sensitivity and selectivity. In addition, to evaluate the anti-bacterial effect of compound 1 in vitro, the P.gingivalis growth curves were measured. And the relative expression of ragA and ragB was detected by RT-PCR to reveal the mechanism of the compound in the anti-infectious activity. The potential anti-infectious criteria that has been observed in the experimental measurement has been further studied by using molecular docking technique.

Load-holding after the forming load reached the limit of hydraulic press is a sufficient method to promote further forming and ensure the filling quality of large Al-5.9Zn-2.1Mg-2.1Cu (wt%) alloy die forgings. To investigate the deformation behavior of the alloy during load-holding process, the thermophysical simulation tests at the holding pressure range of 20–60 MPa, temperature range of 350–450 ℃ with the pressure-holding time of 5–30 s and/after compression tests with the strain rate of 1 s−1 and strain of 0.231 were conducted on a Gleeble-3500 isothermal simulator. The strain rate variation during pressure-holding reveals that the critical holding pressure of accelerating deformation is between 40 and 60 MPa at the temperature higher than 400 ℃. The microstructures of the tested specimens were analyzed by optical microscopy (OM) and electron back-scattered diffraction (EBSD). The pre-deformation promotes the intragranular deformation and hinders grain rotation during following pressure-holding process. Besides, the processing map based on Kumar-Prasad criterion is not as accurate as that based on Murty-Rao criterion in predicting the instability during pressure-holding. Based on the processing map and microstructure analysis, the best pressure-holding conditions are recommended to be 400 ℃&40 MPa, 450 ℃&40 MPa and 450 ℃&60 MPa.

Infrared spectroscopy can accurately reflect the information of molecular vibration, and it is an important technology to characterize the composition and structure of materials. However, since the interaction between nanomaterials and infrared light is very weak due to the significant size mismatch, it is challenging to obtain the spectral information of nanomaterials in the field of infrared spectroscopy. The plasmon is a collective electron oscillation on the surface of the material inducing by the incident light, and it has excellent light field confinement, which can significantly enhance the interaction between light and nanomaterials. Graphene plasmon has prominent properties, such as high light field confinement, dynamic adjustment, and low intrinsic attenuation. Therefore it is an important solution to enhance the infrared absorption of nanomaterials. This article systematically introduces the infrared plasmon materials system. Then it summarizes the characteristics of graphene plasmon and their advantages on surface enhanced infrared spectroscopy, and it emphasizes the recent important researches and applications of graphene plasmon enhanced infrared spectroscopy in the world, including single molecular layer biochemical detection, gas identification, refractive index sensing, etc. Further prospects for the development and potential applications of graphene plasmon enhanced infrared spectroscopy are also demonstrated.

Pipeline system vibration is one of the significant factors leading to the vibration and noise of vessel. Elbow is widely used in the pipeline system. However, the researches about vibration of elbow are little, and there is no systematic study. In this research, we firstly analysed the relationship between elbow vibration transmission characteristics and bending radius by ABAQUS finite element simulation. Then, we conducted the further vibration test to observe the vibration transmission characteristics of different elbows which have the same diameter and different bending radius under different flow velocity. The results of simulation calculation and experiment both showed that the vibration acceleration levels of the pipeline system decreased with the increase of bending radius of the elbow, which was beneficial to reduce the transmission of vibration in the pipeline system. The results could be used as reference for further studies and designs for the low noise installation of pipeline system.

A series of dithiolene nickel complex compounds with a general formula (RCSCSR′) 2 Ni that have an intense absorption band in near-IR region were successfully synthesized and the maximum IR absorption wavelengths of these dyes vary from 875 to 1495 nm in different solvents. Their characteristics of Q -switching and mode-locking for different lasers were investigated. Q -switched 1064 and 1079 nm laser with a polymer film or organic solution work satisfactorily and the pulse widths are 4–10 ns. The dyes in a variety of solutions show excellent properties in mode-locking the 1079 nm laser, particularly in mode-locking the 1340 nm laser. The pulse widths are 90–120 ps. The experimental results show that the choice of different ring substitutes and solvents will greatly influence the corresponding dye laser properties. It is also implied that BDN16 and BDN17 as the mode-locking dyes for the 1500 nm laser are satisfactory.

Latex particles with a multihollow structure were prepared by seeded emulsion polymerizatoin. Thus seed latexes Sn, consisting of styrene(St) and methyl methacrylate (MMA) copolymer, and Sa, consisting of St‐MMA‐AA (acrylic acid) copolymers, were first prepared, then a series of core‐ shell composite latexes SnCa, SnCn, SaCa and SaCn were synthesized with or without AA in the absence of emulsifiers in the second step. Final latexes were then treated by alkali and acid subsequently at 90°C for 3 h. TEM observation showed that only SnCa and SaCa (prepared with AA in the second polymerization, suffix “a” means with AA, “n” means without AA) produced multihollow structures in the particles, and their particle volumes increased 42% for SnCa and 23% for SaCa after the treatment in comparison with original latex particles. No hollows were observed for SnCn and SaCn particles prepared without AA and new particles were formed for the SaCn latex in the second step polymerization. © 1997 by John Wiley & Sons, Ltd.

TEM and PL combined with the RBS technique have been used to investigate the rapid-thermal-annealing-induced structural and optical properties of Yb-implanted silicon. For anneals at 800, 900 and 1000 degrees C, the initial recrystallization of the amorphous layer is epitaxial, followed by a disruption of the regrowth with the remaining damaged region rich in planar defects with plenty of precipitates observed in the recrystallized region. In the same annealing regime, the best crystal quality and highest intensity of PL are observed for the sample annealed at 1000 degrees C. During annealing, Yb segregates not only at the crystal-amorphous interface but also at the surface at the same time. For the anneal at 1200 degrees C, however, almost all the Yb has piled up at the surface, which leads to the disappearance of the PL although the amorphous layer has regrown completely with an excellent crystal quality. It is proposed that both the amount of Yb incorporated into the epitaxially recrystallized region and its crystal quality are responsible for the efficiency of optical activation.

The behavior of ion-beam-induced crystallization of a buried amorphous layer created by means of MeV Si+ irradiation at 300°C in Si(100) was studied by Rutherford backscattering and channeling technique. Solid phase epitaxial crystallizations occurred from both the front and the back amorphous-crystalline (a/c) interfaces with the growth thickness being increased linearly with increasing dose of the annealing ion beam. Nuclear energy deposition was proved to play a dominant role in the process of ion-beam-induced crystallization. The high density of electronic excitation, which could enhance defect production near or at the a/c interface, may thus enhance the nuclearly normalized growth rate of ion-beam-induced crystallization at the front a/c interface.

The rapid thermal annealing temperature dependence of solid phase epitaxial recrystallization and incorporation of Er-implanted silicon has been studied. It was observed that the initial recrystallization is epitaxial. followed by a disruption of regrowth in the doped region for the samples irradiated with 350 keV and 150 keV Er ions to doses of 1 x 10(15) cm(-2) and 7 x 10(14) cm(-2) respectively. The maximum incorporation concentration in the regrowth area for the former decreases with increasing annealing temperature. However, an anomalous enhancement of the maximum incorporation concentration is observed after annealing at 850 degrees C for the latter.

The lattice damage accumulation in GaAs and Al0.3Ga0.7As/GaAs superlattices by 1 MeV Si+ irradiation at room temperature and 350-degrees-C has been studied. For irradiations at 350-degrees-C, at lower doses the samples were almost defect-free after irradiation, while a large density of accumulated defects was induced at a higher dose. The critical dose above which the damage accumulation is more efficient is estimated to be 2 x 10(15) Si/cm2 for GaAs, and is 5 x 10(15) Si/cm2 for Al0.8Ga0.7As/GaAs superlattice for implantation with 1.0 MeV Si ions at 350-degrees-C. The damage accumulation rate for 1 MeV Si ion implantation in Al0.3Ga0.7As/GaAs superlattice is less than that in GaAs.

Extended electron energy loss fine structure (EXELFS) spectra have been obtained from the K-level of oxygen in NiO films grown on both the Ni(100) and Ni(110) surfaces. The spectra indicate that the oxide films grown on both surfaces have Ni-O bond lengths of 2.08 A, identical to those of bulk NiO. These analyses agree with previous measurements on the Ni(100) surface. As in previous experiments the actual measurements made is of N ( E ) rather than direct measurement of the electron energy loss distribution N ( E ). The EXELFS spectra from these two surfaces are used to illustrate the influence of this collection scheme on the radial distribution function obtained by Fourier transformation of the raw data. To obtain the direct analog of the radial distribution function found from the EXAFS experiment one must either resort to spectral integration or appropriate scaling of the distribution function found from the EXELFS experiment.

Graphene plasmons have aroused a great deal of research interest in recent years due to their unique features such as electrical tunability, ultra-strong field confinement and relatively low intrinsic damping. In this review paper, we summarize the fundamental optical properties of localized and propagating plasmons supported by graphene, and the experimental techniques for excitation and detection of them, with focusing on their dispersion relations and plasmon-phonon coupling mechanism. In general, the dispersion of graphene plasmons is affected by the Fermi level of graphene and the dielectric environment. The graphene plasmons can exist in a broad spectrum range from mid-infrared to terahertz. This has been experimentally verified for both the localized and propagation plasmons in graphene. On the one hand, the excitation frequency and confinement of localized plasmons supported by graphene micro/nano-structures are constrained by the structural geometry. Additionally, influenced from the tunability of the optical conductivity of graphene, the excitation frequency of graphene plasmons can be tuned by electrostatic or chemical doping. On the other hand, propagating plasmons have been launched and detected by using scattering-type scanning near-field optical microscopy. This technique provides the real-space imaging of the electromagnetic fields of plasmons, thereby directly confirming the existence of the graphene plasmons and verifying their properties predicted theoretically. In a similar regime, the launching and controlling of the propagating plasmons have also been demonstrated by using resonant metal antennas. Compared to metal plasmons, graphene plasmons are much more easily affected by the surroundings due to their scattering from impurity charges and coupling with substrate phonons. In particular, graphene plasmons can hybridize strongly with substrate phonons and there are a series of effects on plasmon properties such as resonance frequency, intensity and plasmon lifetime. The designing of the dielectric surrounding can effectively manipulate the graphene plasmons. Finally, we review the emerging applications of graphene plasmon in the mid-infrared and terahertz, such as electro-optical modulators and enhanced mid-infrared spectroscopy.

Rutherford backscattering/channeling technique has been used to investigate the lattice damage caused by 1MeV Si+ implantation into Al0.3Ga0.7As/GaAs superlattices and GaAs at elevated substrate temperature and room temperature for different doses. For elevated substrate temperature irradiation, a dose range for balance between defect production and dynamic annealing, and a critical dose for unbalance between them are observed for both Al0.3Ga0.7As/GaAs superlattices and GaAs. The superlattices are more difficult to be damaged than GaAs, and the critical dose for the former is also larger than that for the latter. The hot spot and knock-on model is used to interpret the temperature and dose dependence of damage accumulation in the two materials. The ralative bona strength in GaAs and ＡｌxＧａ1-xAs are calculated using CNDO/2 quantum chemistry method to explain the differences of damage accumulation in Al0.3Ga0.7As/GaAs superlattices and GaAs.

A systematic investigation of 100 keV proton-irradiated polypropylene has been carried out using mechanical tests and infrared spectroscopy. Some other polymers such as polyethylene, polyvinyl chloride, polystyrene, polyacrylic nitride and natural resin are also studied by proton, γ-ray and neutron irradiation for comparison. The experiments have shown that the mechanical properties of proton-irradiated polypropylene have dramatically changed, and both its elongation and tensile strength increase significantly at certain irradiation doses, while the other polymers undergo a rapid degradiation after 100 keV proton irradiation. The infrared spectra indicate that conformational changes have taken place in the polypropylene under proton bombardment, such as the transition from an ordered to a disordered state in the crystalline region of polypropylene, with the formation of double bonds as well as trans-conformations. This leads to the cross-linking between macromolecules of polypropylene at proper irradiation doses, thus enhancing its mechanical properties; such changes may have some potential applications.