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Thin film lithium niobate on insulator (LNOI), as an emerging photonic material, provides a promising platform to realize compact, high-speed, and high-efficient electro-optic (EO) modulators. However, due to the large coupling loss caused by the large mode field mismatch between standard single mode fibers and the LNOI waveguides, edge or grating couplers are indispensable to LNOI modulators. In this paper, we propose a novel edge coupler employing staircase structure. The proposed coupler is feasible with i-line lithography and avoids high precise alignment. Moreover, such coupler can be applied to wafer-scale manufacture with low cost. The simulation results show that a low input/output coupling loss of 1.14 dB/1.62 dB can be achieved at 1.55 m wavelength for transverse electric (TE) polarized light signals. Specifically, benefited from the novel staircase design, the proposed edge coupler shows a unique property of polarization extinction ratio larger than 10 dB, which will further improve the modulation efficiency and depth of the EO modulators based on X-cut LNOI.

AlGaN/gallium nitride (GaN) ion-sensitive field-effect transistors (ISFETs) were fabricated as pH sensors. The sensitivity of the AlGaN/GaN ISFETs was evolved with gate recess process and ammonium hydroxide (NH4OH) treatment. By performing the gate recess process, the threshold voltage ( ${V}_{\text {T}}$ ) of the ISFET increased from −3.33 to −0.31 V and the maximum conductance ( ${G}_{\text {M}}$ ) of the ISFET increased from 0.8 to 2 mS, with the current sensitivity of the pH sensor improving from 52.25 to $78.86~\mu \text{A}$ /pH. Further, after performing the ammonium hydroxide treatment, the ${V}_{\text {T}}$ of the ISFET increased from −0.33 to −0.14 V, with the current sensitivity of the pH sensor improving from 78.86 to $84.39~\mu \text{A}$ /pH. To characterize the surface conditions the X-ray photoelectron spectroscopy (XPS) was deployed. The results indicated that many nitrogen vacancies ( ${V}_{\text {N}}$ ) were introduced during the recess process, leading to a negative ${V}_{\text {T}}$ shift and a smaller potential sensitivity ( ${S}_{V}$ ), which can be improved by ammonium hydroxide treatment.

We propose a long-period grating assisted directional coupler in lithium niobate (LN) for the realization of electro-optic tunable mode filtering functionality. Our typical device, fabricated with the annealed proton-exchange process and designed for filtering out the fundamental mode in a two-mode LN waveguide, achieves a maximum mode extinction ratio of 29 dB at 1551.7 nm wavelength and a –20 dB bandwidth of ∼2.5 nm with an electrical wavelength tuning sensitivity of 0.182 nm/V.

Identifying the form of superconducting order parameter is still a controversial problem for the iron-based superconductor FeSe. Based on anisotropic two-component Ginzburg–Landau theory, we study the temperature dependence of upper critical field and London penetration depth for FeSe. Without including the spin paramagnetic effect, all of our theoretical calculations fit the experimental data well in a broad temperature range. Our results thus show that FeSe is a two-gap s-wave superconductor. And the anisotropy of effective masses in the band with larger (or smaller) gap can be estimated as about 10 (or 2) respectively.

We propose a novel scheme for coupling between fibers and submicron lithium niobate on insulator (LNOI) waveguides. LNOI is bonded on D-shaped SMF to realize efficient evanescent coupling. © 2020 The Author(s)

The idea of sulfidation of metal-organic frameworks (MOFs) has provided a prospective routing to synthesize metal sulfides, which has all kinds of shapes here. Herein, the invaginated hexagonal In2S3 nanorods with hollow structure were successfully fabricated by sulfidation of In-MOF (MIL-68-In) precursor. The obtained In2S3–8h exhibits high catalytic performance for the photodegradation of tetracycline hydrochloride (TC) and methyl orange (MO). The advantageous crystallinity and optical property have effectively promoted more an efficient separation of photo-induced electron–hole pairs, resulting in the enhanced photocatalytic activity. In this work, we put forward a new strategy, which aims to synthesize the traditional semiconductor photocatalysts by sulfidation of MOFs for eliminating environmental pollutions.

Trabecular bone, widely presented in the ends of long bones and chine, is a typically porous structure which provides a multifunction such as light weight, undertaking load, impact energy buffer and hosting marrow cells. The structure of trabecular is a dominant factor for the strength of cancellous bone. The prediction of the trabecular bone’s mechanical properties depending on the trabecular structure is very useful for the diagnosis and treatment of osteoporosis. The object of this study is to establish a relationship between the mechanical properties and topological, morphological parameters of trabecular bone. The 50 3-D data of cancellous bone are selected from the CT images of three caput femurs and disposed in BoneJ, through which the BV/TV, SMI and genus parameters of each samples are obtained. The deformation behaviors of trabecular bone are simulated in ABAQUS through uniaxial compression on the 3-D model derived from stack images. Then linear-regression analyses are conducted on the BV/TV, genus, SMI and apparent Young’s modulus, resulting a high correlation (R^2=0.84) between the Young’s modulus and the hybrid parameter derived from SMI and normalized genus, corresponding to morphological and topological parameter of the samples respectively. The result indicates that it’s promising to establish the relationship between mechanical properties of trabecular bone and their topological and morphological parameters.

A tanghulu-like NiO microcubes on Co3O4 nanowires array anchored on Ni foam was prepared via a facile method. As a pseudocapacitor electrode, the hybrid array exhibits a specific capacitance as high as 2691 mF cm-2 at 2 mA cm−2 and good cycling stability of 84.62% retention after 2000 cycles. Remarkably, the NiO/Co3O4/NF composite demonstrates about 2 times higher specific capacitance than that of Co3O4/NF precursor at a current density of 2 mA cm−2. The improved electrochemical performance could be attributed to the synergistic effect of uniqure tanghulu-like wire-penetrated-cube hybrid arrays on Ni foam conductive substrate. Most importantly, a red light-emitting diode (LED) can be illuminated by two connected ASCs, indicating that as-synthesized NiO/Co3O4/NF possesses great potential for practical applications.

Hollow double–shelled NiO nanospheres have been successfully prepared by the calcination of Ni–based MOF precursor at proper temperatures. The morphology and phase structure of NiO samples were characterized by SEM, TEM, XRD and FTIR. Electrochemical studies indicate that NiO nanospheres obtained under different conditions have distinct electrochemical performances. Hollow double–shelled NiO nanospheres calcined at 400 °C (N400) exhibit the best charge storage with a specific capacitance of 473 F g−1 at the current density of 0.5 A g−1 and with 94% capacitance retention even after 3000 cycling tests. For this merits, the N400//active carbon (AC) asymmetric supercapacitor (ASC) was assembled to examine the practical application of the N400 sample, which presents high energy density of 21.4 Wh kg−1 at power density of 375.8 W kg−1. Particularly, the N400//AC ASC exhibits outstanding cycling stability, and its capacitance retention can still reach up to 92.3% after 3000 cycles. These results indicate that the N400 sample is a promising electroactive candidate for supercapacitors.

Based on the inner filter effect, a luminescent Zn(ii)/Na(i) metal-organic framework (MOF) {[Zn2Na(L)(HL)2(H2O)2][OAc]·2H2O}n (1, H2L = 5-methyl-1,3-benzenedicarboxylic acid) with excellent stability was constructed for the fluorescence detection of Cu2+ ions. MOF 1 holds a 3D cationic framework in which [(OAc)2(H2O)2]n2n- anions are embedded into its 1D channels. Abundant hydrogen-bonding and π-π interactions in the MOF facilitate electron transfer from ligand-to-metal, resulting in a good luminescence peak at 412 nm and an efficient fluorescence quenching of MOF 1 in the presence of Cu2+ ions, due to the inner filter effect. The interactions between the Cu2+ ions and the OAc- anion in the channel endowed the Cu2+ ions with facile access to be adsorbed, and afforded the selective quenching of fluorescence. The MOF particles are well dispersed in water and the Cu2+ ions are pre-concentrated by adsorption, thus facilitating the determination of Cu2+ ions with a detection limit down to 0.65 μM. Our work thus paves a way for developing MOFs as an appealing platform to construct materials for environmental applications.

The development of photocatalysts based on covalent organic frameworks (COFs) is intriguing research due to their structural flexibility and tremendous catalytic sites. Herein we demonstrate a facile strategy to prepare composite materials of combined COFs and inorganic semiconductors with enhanced photocatalytic performances. A new composite photocatalyst (BiOBr/CTF-3D) integrated three-dimensional (3D) covalent triazine framework (CTF-3D) with two-dimensional BiOBr nanoflake was prepared via a simple coprecipitation method. The structural characterizations demonstrated that the amorphous CTF-3D was well modified on the surfaces of BiOBr. The photocatalytic activity of the BiOBr/CTF-3D composite was evaluated by the degradation of colorless antibiotic agents, tetracycline hydrochloride (TC) and ciprofloxacin (CIP), under visible light irradiation. When the mass percent of CTF-3D was 2%, the BiOBr/CTF-3D composite displayed the highest photocatalytic activity. The enhancement of photocatalytic performance...

The preparation of highly active, sustainable, nonprecious metal materials as hydrogen evolution and oxygen evolution reaction (HER and OER) catalysts that can relieve the environmental pollution and energy shortage problems present a great challenge to chemists. We herein report the fabrication of a highly active metal phosphide–carbon composite catalyst for HER and OER in acid and basic solution, respectively. The catalyst is derived through carbonization and subsequent phosphorization of two-dimensional (2D) cobalt porphyrinic metal-organic framework nanosheets. It consists of cobalt phosphide nanoparticles embedded in mesoporous N-doped graphitic carbon materials. The catalyst shows good electrocatalytic activities for HER in 0.5 M H2SO4 and OER in 1 M KOH with overpotentials of 98 and 370 mV at a current density of 10 mA cm–2 and the Tafel slopes of 74 and 79 mV dec–1, respectively. In addition, the catalyst also shows good durability. The method used in this study could be applied to prepare new, hi...

The pyrolysis of metal-organic frameworks has emerged as a promising route to synthesize metal oxides with diverse phase compositions, morphologies, sizes and surface areas. The BiOBr/Bi 24 O 31 Br 10 /TiO 2 (BBT) heterostructures have been achieved for the first time by calcining BiOBr/MIL-125(Ti) composite at 500 °C in air. The BBT-2 composite exhibited the highest photocatalytic performance for degradation of RhB under visible light irradiation. The enhanced photocatalytic activity is attributed to narrower band-gaps and synergistic effect originating from the well-aligned straddling band-structures between BiOBr, Bi 24 O 31 Br 10 and TiO 2 , also result in an faster interfacial charge transfer during the photocatalytic reaction. This work could be conductive to the design of heterostructured photocatalysts contained metal oxide by pyrolytic conversion of metal-organic frameworks for significantly improved photocatalytic performance.

The in situ growth of Bi-based metal–organic framework (MOF) (CAU-17) on BiOBr 2D material was prepared for the first time by using a facile solvothermal transformation approach. The BiOBr was applied both as template to support the growth of MOF and as Bi3+ source of MOF. The BiOBr/CAU-17-2h composite exhibited enhanced photocatalytic activity for degradation of Rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) under visible light irradiation, suggesting a good synergy between BiOBr and CAU-17 MOF.

Electrode materials for supercapacitors with one-dimensional porous nanostructures, such as nanowires and nanotubes, are very attractive for high-efficiency storage of electrochemical energy. Herein, ultralong Cu-based porous coordination polymer nanowires (copper-l-aspartic acid) were used as the electrode material for supercapacitors, for the first time. The as-prepared material exhibits a high specific capacitance of 367 F g-1 at 0.6 A g-1 and excellent cycling stability (94% retention over 1000 cycles). Moreover, porous CuO nanotubes were successfully fabricated by the thermal decomposition of this nanowire precursor. The CuO nanotube exhibits good electrochemical performance with high rate capacity (77% retention at 12.5 A g-1) and long-term stability (96% retention over 1000 cycles). The strategy developed here for the synthesis of porous nanowires and nanotubes can be extended to the construction of other electrode materials for more efficient energy storage.

To explore catalysts combining highly accessible specific surface areas with low recombination of the photo-induced electron-hole pairs, a novel SiO2@PDA@BiOBr composite photocatalyst with a hierarchical core-shell structure was prepared by a facile solvothermal method. The catalyst shows a superior performance on photodegradation of Rhodamine B under visible light irradiation, especially for SiO2@PDA-2@BiOBr with the reactant kinetics constant (k = 0.0487 min-1). The enhanced photocatalytic performance of SiO2@PDA-2@BiOBr was ascribed to the decreased band-gap, higher surface area, and effectively photo-generated electron-hole pairs by the introduction of polydopamine (PDA). In addition, the photocatalytic degradation is initiated by ˙O2- derived from dye photosensitization and h+ from the BiOBr. Cyclic experiments also indicate that the SiO2@PDA-2@BiOBr is reusable during the photodegradation process. The hierarchical core-shell SiO2@PDA@BiOBr photocatalyst will provide a theoretical model for the development of physical chemistry and structural properties of BiOBr-based composites to enhance the photocatalytic performances.

A hierarchical NiO/NiMn-LDH nanosheet array on Ni foam was prepared via a facile two-step approach and exhibited a high specific capacitance (937 F g-1 at 0.5 A g-1) and good cycling stability (91% retention after 1000 cycles at 5 A g-1). The improved electrochemical performance is benefited from the synergistic properties of hierarchical NiO/LDH nanosheet composites on a conductive substrate.

While nondestructive ultrasound-based methods are suitable for evaluating the physical and mechanical properties of lightweight cellular concrete (LCC) materials, the quantitative relation between porosity characteristics and acoustic parameters is not well understood. In this study, the micromechanics-based finite-element models are rebuilt using the real porous microstructure of LCC. Various roles of porosity characteristics are analyzed, including equivalent pore radius, pore sphericity value and fractal dimension of pore distribution with different mixture ratios. Effects of porosity characteristics are quantitatively demonstrated on the ultrasonic pulse velocity. It is shown that the ultrasonic pulse velocity is positively correlated with equivalent pore radius and fractal dimension of pore distribution, and negatively correlated with pore sphericity value and porosity. As the orientation of pores increases, the ultrasonic pulse velocity initially drops, followed by the increase. The quantitative understanding of porosity characteristics on ultrasonic responses helps improve the accuracy of ultrasonic detection on LCC properties. Comparisons between simulation results and experimental data of ultrasonic pulse velocities demonstrate good agreement. This study represents an effective quantitative method to explore the ultrasound propagation in LCC.

In this work, a novel fluorescent probe with first-time-selected thiazepine backbone, TZPzine-1, was developed for selective detection of hydrazine in water samples and living cells. Chosen from our recent anti-cancer agents, TZPzine-1 inferred structurally based advantages of the optical adjustability and the hydrazine-trapping approach. It also showed applicable properties including high sensitivity (LOD = 50 nM), wide linear range (0–15 equiv.), high selectivity (especially from competing species), rapid response (within 20 min), and practical steadiness in various pH (6.0–11.0) and temperature (15–50 °C) conditions. To satisfy the interdisciplinary requirements in environmental toxicology, TZPzine-1 was successfully applied in water samples and living cells. We hope that the information in this work, as well as the concept of monitoring the nitrogen cycle, may be referable for future research on systematic management.

Preparing and designing an epoxy system with ultrahigh glass transition temperature (Tg > 300 °C) is always a big challenge, which restrict its applications in some cutting-edge areas such as aerospace engineering and electrical electronics. Herein, a biomass-based epoxy resin (REEP) was prepared from resveratrol, and then curing behavior, thermal–mechanical properties, mechanical performance, thermal stability, dielectric properties and optical properties of REEP/HDDM, REEP/DGEBA/HDDM and DGEBA/HDDM were respectively studied systematically. Results suggested that the Tg of REEP/HDDM was above 320 °C, higher than those of most reported epoxy systems, both derived from biomass-based and petroleum-based materials. Moreover, the tensile strength of REEP/HDDM, REEP/DGEBA/HDDM and DGEBA/HDDM were 77.8 MPa, 70.8 MPa and 63.6 MPa, respectively, and the Td5% of REEP/HDDM, REEP/DGEBA/HDDM and DGEBA/HDDM were 319.9 °C, 335.1 °C and 348.1 °C, respectively, indicating excellent mechanical performance and thermal stability of the cured epoxy system. Interestingly, the REEP/HDDM exhibited outstanding blocking properties in the range of 220–400 nm (UV-light) and low flammability with compact and continuous char residues. In short, REEP, with a well-defined chemical structure, has a stiffness conjugated stilbene structure to prevent the molecular from motioning in the crosslinked network structure and three epoxy groups, thereby increasing the crosslinked density dramatically, which endows REEP/HDDM network with outstanding comprehensive properties.

When a laser beam irradiates an optical material, a light standing wave field should be observed inside the optical material due to the interference between the beam reflected from the rear surface and the incident beam. If there are scratches on the surface, the incident light can be modulated and the distribution of the standing wave field inside the material is not uniform any more. Therefore, the appearance of the local enhancement of light will change the damage characteristics of optical material. To analyze the field damage characteristics of optical material with scratches, a theoretical analysis model is established. It can be used to study the damage characteristics and build a priori model of actual optical material. Fused quartz is employed as the study object, and the modulation effect of defect on light field is simulated by finite difference time domain (FDTD). Based on the electron multiplication theory, the effect of the number and the positions of scratches on the damage characteristics of fused quartz are calculated in detail. The results show that the phase modulation of the scratch will destroy the uniformity of the standing wave field when the scratch defect material is irradiated by laser. Due to the influence of the standing wave field, the maximum field intensity appears near the rear surface of the material, which explains the phenomenon that the rear surface of the material is more prone to damage points. When there are multiple scratches on the material surface, the distribution of light field is related to the number of the scratches. Specifically, the maximum field intensity increases with the number of scratches increasing. Taking fused quartz material for example, when a 10-ps pulse is incident on it, if three scratches are located on its surface, then the modulation effect on the light field is strongest, and the damage threshold is 66.1% lower than that of the ideal material. In addition, the scratch spacing also has an effect on the standing wave field and field damage characteristics of the material, and the specific effect of the interval can be analyzed directly by using the calculation model proposed in this paper.

The TC4 1 microstructure surface was prepared by using femtosecond pulse laser induction. The three-dimensional topography and scanning electron microscope were used to observe the TC4 alloy surface. Relying on the icing characteristics experimental system to test the ice and frost resistance performance of the microstructure surface, and analyze the influence mechanism of the femtosecond pulse laser processing technology parameters on the surface microstructure and frost suppression properties. The results show that the depth of the grooves on the surface of the TC4 alloy increases as the the laser scanning speed increase, the size of the micro/nano structure increases, the contact angle decreases first and then increases and then decreases; the freezing time of droplets on the machined surface is delayed by 30s than that on the untreated surface; the freezing time of droplets is the longest, the frost layer mass is the lowest and the height is the lowest when scanning speed is 2000 mm/s. The micro-nano structure formed on the surface of TC4 alloy by femtosecond laser processing and the organic matter adsorbed on the surface can change the surface contact angle; the roughness and surface morphology can affect the surface freezing time and frost amount.

Metal-organic frameworks (MOFs) as chemical sensors have developed rapidly in recent years. There have been many papers concerning this field and interest is still growing. The reason is that the specific merits of MOFs can be utilized to enhance sensitivity and selectivity by various energy/charge transfers occurring among different ligands, ligand, and metal centers, such as from ligands to metal centers or metal centers to ligands, as well as from MOF skeletons to guest species. This review intends to provide an update on recent progress in various applications of different MOF-based sensors on the basis of their luminescent and electrochemical responses towards small molecules, gas molecules, ions (cations and anions), pH, humidity, temperature, and biomolecules. MOF-based sensors function by utilizing different mechanisms, including luminescent responses of "turn-on" and "turn-off", as well as electrochemical responses.

Nanorods-composed yolk-shell bimetallic-organic frameworks microspheres are successfully synthesized by a one-step solvothermal method in the absence of any template or surfactant. Furthermore, hierarchical double-shelled NiO/ZnO hollow spheres are obtained by calcination of the bimetallic organic frameworks in air. The NiO/ZnO hollow spheres, as supercapacitor electrodes, exhibit high capacitance of 497 F g(-1) at the current density of 1.3 A g(-1) and present a superior cycling stability. The superior electrochemical performance is believed to come from the unique double-shelled NiO/ZnO hollow structures, which offer free space to accommodate the volume change during the ion insertion and desertion processes, as well as provide rich electroactive sites for the electrochemical reactions.

Transition metal sulfides have complex valence states and exhibit excellent properties and promising applications in supercapacitors. NiS2/ZnS hollow spherical nanocomposites have been successfully synthesized via a facile MOF-derived self-sacrificing route. The synthesis process involves solvothermal method for preparation of Ni/Zn–BDC MOF and subsequently chemical sulfidation treatment to convert into NiS2/ZnS hollow nanospheres. When evaluated as electrode materials in supercapacitor, the NiS2/ZnS hollow nanospheres exhibit high capacitance of 1198 F g−1 at the current density of 1 A g−1. Moreover, an asymmetric supercapacitor based on NiS2/ZnS hollow nanospheres as the positive electrode and activated carbon (AC) as the negative electrode achieves an energy density of 28.0 W h kg−1 at a power density of 478.9 kW kg−1. The results suggest the NiS2/ZnS hollow nanospheres are promising electrode materials for high-performance supercapacitors.

Metal–organic frameworks (MOFs) are considered as suitable materials for various applications in the area of photocatalysis. On the other hand, 2D BiOBr materials are efficient for the photodegradation of organic dyes under visible light illumination. In this work, BiOBr/NH2-MIL-125(Ti) composite photocatalysts with different NH2-MIL-125(Ti) content were prepared by incorporating NH2-MIL-125(Ti) with BiOBr using a co-precipitation method. A series of characterizations confirmed the strong synergistic effect between BiOBr and NH2-MIL-125(Ti). In rhodamine B (RhB) degradation experiments, the composite photocatalyst with a mass percent of 7 wt% NH2-MIL-125(Ti) exhibited an improved photocatalytic activity compared to pristine BiOBr and NH2-MIL-125(Ti). Furthermore, the enhanced photocatalytic performance under visible light illumination could be attributed to the Ti3+–Ti4+ intervalence electron transfer and synergistic effect between NH2-MIL-125(Ti) and BiOBr, and also resulted in a separation efficiency of photo-generated electron–hole pairs during the photocatalytic reaction. This study can open up numerous opportunities for the development of various MOF-based visible light photocatalysts when combined with 2D bismuth oxyhalide materials for applications in environmental cleaning.

Fly ash has been used to fill the lightweight cellular concrete (LCC) as the primary admixture to promote comprehensive engineering applications. However, the strengthening mechanism of LCC resulted from fly ash is not well understood. In this paper, the strengthening mechanism of LCC filled with fly ash (LCCFFA) was investigated with respect to the microstructures including porosity and skeleton characteristics. The variation rules of average pore size (PS), pore roundness value (PRV), and fractal dimension of pore distribution (FDPD) with different fly ash contents were explained. The relationship between microscopic parameters of PS, PRV, and FDPD and the overall compressive strength, along with the wet bulk density was established. Furthermore, the difference of skeleton structure evolution mechanism between LCC and LCCFFA was investigated with the results showing that the difference comes from the effects of ball and particle filling of fly ash when before 28 days. While after 28 days, the pozzolanic reaction of fly ash and hydration reaction of cement mutually promote the densification of skeleton structure. Finally, the SEM energy spectrum diagram was analyzed to further reveal the strengthening mechanism. From the perspective of characteristic pore parameters and skeleton hydration products, the recommended content of fly ash is approximately 25%. The ratio between Si and Ca (Si/Ca) can determine the degree of reaction of fly ash, and can therefore be used as a judging criterion to determine whether the content of fly ash is appropriate.

Metal-organic frameworks (MOFs) as a promising electrode materials have received increasing attention in supercapacitors. The construction of nanoscale MOF materials was considered as an effective strategy to enhance electrochemical performances. In this work, CuMOF crystal and NiMOF crystal are synthesized by selecting redox-active organic linker and metal centers. Then, an in-situ solvothermal method is developed and applied successfully to prepare their nano materials, named as nano-CuMOF 1–10 and nano-NiMOF 1–10, under a facile and mild condition. In particular, it is found that various morphology and nano sizes for these nano-CuMOFs and nano-NiMOFs can be effectively controlled based on solvent effect and surfactant effect. All structures of as-synthesized nano materials are demonstrated by XRD and FT-IR results, which are consistent with the ones of their crystals. More importantly, electrochemical properties can be greatly enhanced from bulk crystals of CuMOF and NiMOF to nano-CuMOF and nano-NiMOF materials. Their nano materials exhibit excellent supercapacitor performance. Among of them, nano-NiMOF 3 as supercapacitor electrode shows the best specific capacitance of 1024.44 F g−1 at a current densities of 1 A g−1 and maintains very good cycling stability. Its capacitance retention of 49.07% can be observed after 5000 cycles at a current density of 5 A g−1. In addition, a high-performance asymmetric supercapacitor (ASC) was fabricated by using nano-NiMOF 3 and activated carbon as two electrodes. A specific capacitance of 38.65 F g−1 was obtained at a current density of 0.5 A g−1, and 109% capacity of the initial capacitance at 3 A g−1 after 5000 cycles can be observed.

Ti/7YSZ composite coating system was prepared on the surface of TC4 titanium alloy by laser cladding using YLS-3000 fiber laser system, The macroscopic feature, microstructure, element distribution and hardness distribution of Ti-Based Laser Cladding Ti＋7YSZ composite thermal barrier coatings were characterized by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results showed that Ti-based composite thermal barrier coating system changes the microstructure from top to bottom at different laser scanning speeds. It is mainly composed of acicular α’ martensite, martensite core, α phase bundle and residual β phase, which has the characteristics of “Fine up and down, coarse in the middle”. Due to surface tension, buoyancy, molten pool agitation and self-density. Zr element is enriched in the binding zone, and its signal intensity level increases first and then decreases as the scanning speed increases. Due to the dislocation slip resistance between the martensite and the solid solution strengthening effect of the Zr forming replacement solid solution, the hardness of the cladding zone is significantly higher than that of the structure, which is 2.5 times that of the TC4 structure.

Exploring sustainable biobased thiol-ene crosslinked networks with inherent fluorescence, high comprehensive properties as well as low-toxicity will significantly expand their applications in display, anti-counterfeiting, and biomedical materials, etc. In this work, resveratrol allyl ether (RAE), a novel multifunctional allyl compound, was prepared from sustainable feedstocks, and a series of thermosetting materials were designed by tuning the functionality of thiol compounds (from two to four) via UV-light induced thiol-ene click reaction. The curing behavior, thermal and thermomechanical performance, mechanical properties, and biotoxicity of these thiol-ene crosslinked networks were investigated, respectively. Results showed that RAE-4SH exhibited the highest Tg and mechanical properties. Specifically, the Tg of RAE-4SH was up to 71.2 °C; meanwhile, the tensile strength and modulus were as high as 49.5 MPa and 1.2 GPa, respectively. Interestingly, it also performed exceptional strong blue-fluorescence under the excitation of UV-light due to the inherent conjugated structure. Moreover, the MTT and cell experiment confirmed low-toxicity of RAE-4SH. Finally, several complex patterns including “BUCT”, a flower, and a two-dimension code can be easily prepared with the help of the photo mask. To summarize, RAE provides a new strategy to explore the biomass resources to prepare high-performance functional materials, which may greatly enlarge its application in the future.

Non-noble-metal electrocatalysts for water splitting hold great promises for developing sustainable and clean energy sources. Herein, a highly efficient bifunctional electrode consisting of Ni-doped molybdenum nitride nanorods on Ni foam is prepared through topotactic transformation of NiMoO4 nanorods that are in situ hydrothermally grown on Ni foam. The electrode not only contains rich, accessible, electrochemically active sites but also possesses extraordinary chemical stability. It exhibits excellent hydrogen evolution reaction and oxygen evolution reaction performance in 1.0 M KOH with low overpotentials of 15 and 218 mV, respectively, at a current density of 10 mA cm-2, superior to the commercial benchmark materials Pt/C and RuO2 under the same condition. A simple water electrolyzer using the obtained electrode as both the anode and cathode needs a very low cell potential of 1.49 V to reach a current density of 10 mA cm-2 and maintains stability for 110 h without degradation. The excellent performance of the electrode could be attributed to the formation of highly conductive, corrosion- and oxidation-resistant metal nitrides and the synergetic effect between intimately interconnected, electrochemically active nickel molybdenum nitride and Ni or NiO nanoparticles. This study shows that the use of transition metal nitrides in combination of nanostructured heterojunctions of multiple active components enables one to develop highly stable and efficient water electrolyzers without precious metals. The preparative strategy used in this work could be applied to devise new electrocatalysts.

Metal-organic frameworks (MOFs) show great advantages as new kinds of active materials for energy storage. In this study, bimetallic metal-organic frameworks (Ni/Co-MOFs) with nanosheet-assembled flower-like structures were synthesized by etching Ni-MOF microspheres in a cobalt nitrate solution. It can be clearly observed that the amount of Co(NO3)2 and etching time play crucial roles in the formation of Ni/Co-MOF nanosheets. The Ni/Co-MOFs were used as electrode materials for supercapacitors and the optimized Ni/Co-MOF-5 exhibited the highest capacitances of 1220.2 F g-1 and 986.7 F g-1 at current densities of 1 A g-1 and 10 A g-1, respectively. Ni/Co-MOF-5 was further sulfurized, and the derived Ni-Co-S electrode showed a higher specific capacitance of 1377.5 F g-1 at a current density of 1 A g-1 and a retention of 89.4% when the current density was increased to 10 A g-1, indicating superior rate capability. Furthermore, Ni/Co-MOF-5 and Ni-Co-S showed excellent cycling stability, i.e. about 87.8% and 93.7% of initial capacitance can be still maintained after 3000 cycles of charge-discharge. More interestingly, the Ni/Co-MOF-5//AC ASC shows an energy density of 30.9 W h kg-1 at a power density of 1132.8 W kg-1, and the Ni-Co-S//AC ASC displays a high energy density of 36.9 W h kg-1 at a power density of 1066.42 W kg-1. These results demonstrate that the as-synthesized bimetallic Ni/Co-MOF nanosheets and their derived nickel-cobalt sulfides have promising applications in electrochemical supercapacitors.

A novel 3D flower-like morphology of U/Bi2WO6 composite was successfully synthesized by the hydrothermal method assisted by sodium dodecyl sulfate using Bi(NO3)3·5H2O, Na2WO4·2H2O and UO2(CH3COO)2·2H2O as precursors. The shape of as-prepared product presents a good flower-like particle, and a higher photocatalytic activity of the sample is found which methylene blue can be completely degradated in 50 min under visible light irradiation and in 30 min under UV light irradiation.

In this article, a kind of synthetic polymer dust suppressants agent was prepared with poly (vinyl- alcohol) (PVA), carboxymethylcellulose (CMC) and acrylamide (AM). The chemical and physical properties of this dust suppressant was characterized by means of grafting rate, FT-IR analysis, TG test, viscosity analysis and SEM survey. The result showed that grafting rate was reached 95.6%; IR spectrum proved that monomers have been completely reacted basically; thermal gravimetric analysis was characterized that the dust suppressant has good thermal stability between 0°C-250°C; the amount of AM and SDBS were 50% and 1.0% (based on mass of the total materials), the polymer has a suitable viscosity; SEM was used to observe the shape characteristic of the coal dust which formed a link between the dust suppressant and coal dust. The water resistance of the dust suppressant was well in 24h.

A new type of proportion cycle temperature control algorithm is proposed in this paper. Controller can automatically identify temperature constant related to the heater power, combined with the real time environmental temperature change, dynamically modify the heating and cooling time, controlled volatility in setting temperature range.When the mutant short time ambient temperature occurs, it can make rapid response, so as to achieve better control effect.

The current paper mainly addresses the effect of the hydrogen partial pressure on the microstructure and transformation of the Ag$_2$O film. The transformation process and mechanism were also analyzed in detail. Increasing the hydrogen partial pressure can accelerate the transformation of Ag$_2$O to Ag and lower the critical transformation temperature of the film due to the enhanced hydrogen reduction, and to both of the lowered activation energy of the reaction of Ag$_2$O with hydrogen and enhanced lattice strain of the Ag$_2$O film, respectively. Hydrogen-involved reaction in the whole hydrogen annealing process is mainly hydrogen reduction reaction with Ag$_2$O. The diffusion of hydrogen and gaseous H$_2$O molecules is accompanied with the whole hydrogen annealing process., This manuscript will appear in Volume 43 of the Brazilian Journal of Physics

Controlled synthesis surface-clean monolayer graphene was achieved. Monolayer Graphene was achieved by mechanical exfoliation (ME) and chemical vapor deposition (CVD),and then transferred to SiO2 (300nm)/Si substrates. There were tape residues left on the surface of the ME graphene, and poly (methyl methacrylate) (PMMA)/photoresist residues left on the surface of the CVD graphene after the transferring and lithography process. Annealing method was used to clean all these kinds of residues. Annealing processes were performed at different temperatures in both vacuum and N2/H2. It is conclude that N2/H2 is crucial for the removing of residues, and 400°C is favorable for removing the residues. Atomic force microscope (AFM) images and Raman spectra were taken to confirm the effect of the annealing.

The high-quality phosphorus-doped ZnO nanocombs were synthesized by the simple chemical vapor deposition method without use of any catalyst. The images of field-emission scanning electron microscopy show that the phosphorus-doped ZnO nanocombs have a uniform length of 8 μm with the diameter of 70 nm and the cusp of the teeth of 20 nm. The measurement results of selected-area electron diffraction pattern indicate that the phosphorus-doped ZnO nanocombs are single crystalline structure. The phosphorus related acceptor emission was observed in the photoluminescence spectra of phosphorus-doped ZnO nanocombs at 11 K. The acceptor binding energy is estimated to be ∼127 meV.

A hexagonal nanosheet LDH@ZIF-8 composite was fabricated by in situ growth of ZIF-8 on Zn-Al LDH without adding any zinc precursor, and exhibited a CO2 adsorption capacity of 1.0 mmol g(-1) at room temperature and 1 bar, which was significantly higher than that of pure Zn-Al LDH or ZIF-8, indicating a synergy between ZIF-8 and Zn-Al LDH.

A series of 〈111〉 oriented Ag2O films was deposited onto glass substrates by using RF magnetron reactive sputtering at different flow ratios (FRs) of oxygen to argon. The Ag2O film deposited at FR = 0.667 was the best 〈111〉 oriented film due to dual contributions from both lattice strain and film stress. The films’ transmissivity of over 70% in the near-infrared region indicated that Ag2O films are not suitable for applications as transparent conductive films in the visible region. Ag2O films deposited at FRs from 0.467 to 0.800 had optical band gaps ranging from 3.266 eV to 3.107 eV. The redshift in the films’ absorption edge may be attributed to the decrease in the lattice strain with increasing in FR.

One of the main hurdles for the wide use of current Ag-filled conductive composites is the high cost of Ag fillers, while the challenge for low cost copper-filled composites is their poor reliability. In this study, the Ag-coated Cu flakes was chosen as conductive fillers and a surface modification with coupling agent, to achieve good bonding between the flakes and the Polydimethylsiloxane (PDMS) matrix, was applied to improve the mechanical and conductive properties of the PDMS based composites. The resulting composites obtained through modification showed an increase in hardness by 13.1% and tensile strength by 28.4% relative to the composites without coupling agent. In addition, the reliability of conducting composites was discussed and the results showed that the coupling agent played a great role in preventing the corrosion of the exposed Cu during aging. The volume resistivity of the composites, filled with untreated Ag-coated Cu flakes, increased from 0.0039Ω·cm to 0.0059Ω·cm under aging at 85°C and 85% room humidity (RH) in a temperature/humidity chamber for 48 h, in contrary, the volume resistivity shift of the composites with treated flakes was almost negligible, just changed from 0.0043Ω·cm to 0.0045Ω·cm. More importantly, the prepared conductive silicone rubber filled with Ag-coated Cu flakes with the resistivity (0.004Ω·cm) comparable to the relative commercial products can be used for electro-magnetic interference (EMI).

Single-phased and (111)-oriented Ag 2 O film deposited using direct-current reactive magnetron sputtering is annealed using different annealing temperatures ( T a ) for 1 h in Ar and H 2 mixture. After hydrogen annealing, a very weak but clear Ag(200) diffraction peak begins to appear, and the Ag 2 O diffraction peak weakens at T a = 175 °C. However, the Ag diffraction peak becomes discernable at T a = 190 °C. No Ag 2 O diffraction peaks but rather Ag diffraction peaks are discerned at T a = 200 °C. The hydrogen reduction effect can reduce the film's critical thermal decomposition temperature to 175 °C. After hydrogen annealing, the surface of the film evolutes from compact and uniform to osteoporosis, and then to a porous structure. Moreover, the optical properties of the film obviously change at T a over 190 °C, indicating that the hydrogen reduction can significantly enhance the decomposition of Ag 2 O due to H 2 dissociation on the surface followed by gaseous H 2 O molecule formation and desorption.

In this study, a thixotropic agent was applied to improve the aspect ratio of the silicone rubber gasket and the resulting obtained through modification showed an increase in aspect ratio from 0.26 to 0.91 with the relative to the gasket without thixotropic agent. Compared with the silicone rubber without thixotropic agent, the mechanical properties of the silicone rubber with thixotropic agent were discussed and the results revealed that the shift was very small. In addition, using Ag-coated Cu dendritic powder as conductive fillers, conductive silicone rubber with the resistivity (0.004Ω·cm) was prepared comparable to the relative commercial products can be used for electro-magnetic interference (EMI). The reliability of the conductive composites under aging at 85°C and 85% room humidity (RH) in a temperature/humidity chamber for 48 h was also discussed and the results showed that the shift of the volume resistivity was almost negligible which can meet the actual needs completely.

Gallium oxide (Ga2O3) has five crystalline polymorphs, i.e. corundum (α-phase), monoclinic (β-phase), spinel (γ-phase), bixbite (δ-phase) and orthorhombic (ε-phase). Among these phases, the monoclinic structured β-Ga2O3 is the most stable form, and is a ultraviolet (UV) transparent semiconductor with a wide band gap of 4.9 eV. It is a promising candidate for applications in UV transparent electrodes, solar-blind photodetectors, gas sensors and optoelectronic devices. In recent years, one-dimensional (1D) nanoscale semiconductor structures, such as nanowires, nanobelts, and nanorods, have attracted considerable attention due to their interesting fundamental properties and potential applications in nanoscale opto-electronic devices.Numerous efforts have been made to fabricate such devices in 1D nanostructures such as nanowires and nanorods. Comparing with the thin film form, the device performance in the 1D form is significantly enhanced as the surface-to-volume ratio increases. In order to realize β-Ga2O3 based nano-optoelectronic devices, it is necessary to obtain controlled-synthesis and the high-quality β-Ga2O3 nanomaterials. According to the present difficulties in synthesizing β-Ga2O3 nanomaterials, in this paper, the grid-like β-Ga2O3 nanowires are prepared on sapphire substrates via electric field assisted chemical vapor deposition method.High-purity metallic Ga (99.99%) is used as Ga vapor source. High-purity Ar gas is used as carrier gas. The flow rate of high-purity Ar carrier gas is controlled at 200 sccm. Then, oxygen reactant gas with a flow rate of 2 sccm enters into the system. The temperature is kept at 900℃ for 20 min. The effect of the external electric voltage on the surface morphology, crystal structure and optical properties of β-Ga2O3 nanowires are investigated. It is found that the external electric voltage has a great influence on the surface morphology of the sample. The orientation of the β-Ga2O3 nanowires grown under the action of an applied electric field begins to improve. Only a grid composed of three different growth directions appears. And with the increase of applied voltage, the distribution of nanowires becomes denser and the length increases significantly. In addition, it is found that the chemical vapor deposition method assisted by this external electric field can significantly improve the crystallization and optical quality of the samples.

Compositionally gradient CrNx coatings were fabricated using arc ion plating by gradually increasing N2 flow rate during the deposition process. The effect of substrate bias, ranging from 0 to −250 V, on film microstructure and mechanical properties were systematically investigated with XRD, SEM, HRTEM, nanoindentation, adhesion and wear tests. The results show that substrate bias has an important influence on film microstructure and mechanical properties of gradient CrNx coatings. The coatings mainly crystallized in the mixture of hexagonal Cr2N, bcc Cr and fcc rock-salt CrN phases. N2 flow rate change during deposition results in phase changes in order of Cr, Cr + Cr2N, Cr2N, Cr2N + CrN, and CrN, respectively, along thickness direction. Phase fraction and preferred orientation in CrNx coatings vary with substrate bias, exerting an effective influence on film hardness. With the increasing of bias, film microstructure evolves from an apparent columnar structure to a highly dense one. The maximum hardness of 39.1 GPa was obtained for the coatings deposited at a bias of −50 V with a friction coefficient of 0.55. It was also found that adhesion property and wear resistance of gradient CrNx coatings were better than that of homogeneous CrN coatings.

Demands for substrate and film surface planarizations significantly increase as the feature sizes of Integrated Circuit (IC) components continue to shrink. Chemical Mechanical Polishing (CMP), incorporating chemical and mechanical interactions to planarize chemically modified surface layers, has been one of the major manufacturing processes to provide global and local surface planarizations in IC fabrications. Not only is the material removal rate a concern, the qualities of the CMP produced surface are critical as well, such as surface finish, defects and surface stresses. This paper is to examine the CMP produced surface roughness on tungsten or W thin films based on the CMP process conditions. The W thin films with thickness below 1000 nm on silicon wafer were chemical-mechanical polished at different down pressures and platen speeds to produce different surface roughness. The surface roughness measurements were performed by an atomic force microscope (DI D3100). Results show that the quality of surface finish (R a value) is determined by the combined effects of down pressures and platen speeds. An optimal polishing condition is, then, possible for selecting the down pressures and platen speeds.

Subsurface residual stresses of tungsten films induced by Chemical Mechanical Polishing (CMP) processes were investigated by the Grazing Incident X-Ray Diffraction (GIXRD). Basis of the GIXRD measurement was introduced and the experiments were conducted for residual stress of tungsten film measurements. Experimental procedures of the GIXRD measurements were presented. The obtained residual stresses value of tungsten films from 800 nm to 400 nm varies from 1086.1 ± 105.2 MPa to 1670.6±103.4 MPa prior and after CMP process.

Three kinds of ZnO nanowire arrays were fabricated on Au coated (1 1 0)silicon wafer by using of heating the mixture of zinc oxide (ZnO) and graphite powders at various depositing temperature. The synthesized samples were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analytic technology, respectively. Structural analyses revealed that the morphologies and crystal microstructures of ZnO nanoarrays were related with the substrate temperature. And control to the growth morphologies can be achieved by carefully tuning the depositing temperature. The testing results to different nanowire arrays showed that the properties of field emission follow the Fowler–Nordheim law. The quais-aligned ZnO nanowire array sample synthesized at 750 °C had the lowest turn-on field of 7.4 V/μm, highest β of 1028. This largest emission efficiency is attributed to the clear tip and appropriate coverage density. As well as the nanowires are straight with long length and parallel to each other with good crystal quality. The experimental results could be very useful for field emission materials and other nanoelectronics device applications.