Search

In this communication, we propose a novel method to electrochemically modify hydrogen-terminated diamond surface in MISFETs with LiF dielectric at room temperature. The chemical reaction is 2F- + C–H+2h+→C–F + HF. According to measurement results of X-ray photoelectron spectroscopy on diamond, C–F bonds were produced after electrochemistry modification. A model was proposed to explain the electrochemistry modification on MISFETs. In this model, the theoretical electrolysis voltage of F− was calculated to be −3.8V, which was consistent with the experimental value of -5V.

A normally OFF hydrogen-terminated diamond (H-terminated diamond) field-effect transistor (FET) has been successfully achieved with Ti/TiO x gate materials. A 5-nm Ti film was deposited on H-terminated diamond by electron beam evaporation technique and then it was thermally oxidized in air at 120 °C for 10 h to form Ti/TiO x , which was confirmed by X-ray photoelectron spectroscopy. The threshold voltage of H-terminated diamond FET is −0.14 V at ${V}_{DS}$ of −8 V, indicating a normally OFF operation. The normally OFF property could be attributed to the difference of work difference between Ti and H-terminated diamond, which may deplete the hole carriers in H-terminated diamond 2-D hole gas (2DHG) conduction channel. The maximum mobility of H-terminated diamond FET is 313 cm2/Vs at ${V}_{GS}$ of −0.2 V. And, the fixed negative charge density is $3.37 \times 10 _{11}$ cm−2. The results demonstrate that Ti/TiO x H-terminated diamond FET is a good solution to fabricate normally OFF device with a simple fabrication process, undamaged 2DHG channel, and uncontaminated interface between Ti and TiO x gate materials, which may promote the development of normally OFF H-terminated diamond FET.

Revealing the intrinsic origin is critical for developing performance-enhancing V2O5 battery-type electrode materials. In this work, ultralong single-crystal V2O5 wires (W-V2O5) and V2O5 plate particles (P-V2O5) with similar physicochemical properties were compared to investigate the possible stimulative factors for pseudocapacitive enhancement. Our results indicate that besides the most-discussed specific surface area (or nanostructure), the enhanced electronic conductivity, the controllable interlamellar spacing distance, and the ion-transporting route as intrinsic origin also greatly affect their pseudocapacitive enhancement. First, the ultralong single-crystal wire structure can apparently enhance the electrons transport; second, the unique [001] facet orientation along the wire direction enlarges the interlamellar spacing distance and shortens the Li+ inserting route, thus facilitating the redox reactions by providing fast channels for charge carrier intercalation. Thus W-V2O5 showed much higher capacitance, better rate, and cycling capability than those of P-V2O5. This new insight presented here provides guidance for the design of V2O5 electrode materials and opens new opportunities in the development of high-performance battery-type electrode materials.

An enhancement-mode hydrogen-terminated diamond field-effect transistor (FET) is realized by using a low work function gate material, namely, lanthanum hexaboride (LaB6). The reason for the enhancement mode should be that the electrons in the LaB6 layer flow into the two-dimensional hole gas (2DHG) channel and compensate the holes, such that the channel is shut down. The threshold voltages ( ${\mathrm {V}}_{\text {TH}}$ ) range from − 0.29 V to − 0.72 V with different gate lengths. The device with 2 $\mu \text{m}$ gate length shows a − 57.9 mA/mm maximum drain current density ( ${\mathrm {I}}_{\text {DSmax}}$ ) at ${\mathrm {V}}_{\text {GS}} =-$ 5 V. The on/off ratio is around 9 orders of magnitude, with a subthreshold swing of 130 mV. Effective mobility ( $\mu _{\text {eff}}$ ) as high as 195.4 cm2/ $\text{V}\cdot \text{s}$ is obtained from the device. This technique reveals undamaged 2 DHG characteristics, uncontaminated interface between LaB6 and aluminum gate metal, and a simple fabrication process, which will promote the development of enhancement diamond FETs.

In this paper, we successfully synthesized homoepitaxial diamond with high quality and atomically flat surface by microwave plasma chemical vapor deposition. The sample presents a growth rate of 3 μm/h, the lowest RMS of 0.573 nm, and the narrowest XRD FWHM of 31.32 arcsec. An effect analysis was also applied to discuss the influence of methane concentration on the diamond substrates.

Localized surface plasmon-enhanced diamond UV photodetectors with different Ir nanoisland arrays had been successfully fabricated. Three different Ir nanoisland arrays with the diameters of 20(D20), 30(D30) and 40(D40) nm were deposited on the diamond surface, respectively, and their height was 10 nm. Ti/Au metal electrodes were patterned on Ir nanoisland arrays area and bare diamond surface to form UV photodetectors. According to photoelectric performance test results, the responsivities of diamond photodetectors with Ir nanoislands were far greater than that of diamond photodetector, and the D40 showed the highest photocurrent and responsivity at 210 nm, and the D20 indicated the highest UV/vis rejection ratio. The results of simulated extinction spectra exhibited three resonance peaks at UV and visible region for each sample, indicating that D20 had the highest ratio of UV/vis, which was coincide with experiment results.

Investigation of influence of floating metal rings (FMRs) edge termination technique on the breakdown voltages of diamond Schottky barrier diodes (SBDs) has been carried out. Unintentionally doped P- drift layer was grown on HPHT boron doped diamond substrate by microwave plasma CVD system and treated by ultraviolet ozone. Then, Ti/Ni/Au electrode was deposited on the back side of the substrate to form ohmic contact. Zr/Ni/Au Schottky electrodes with different FMRs parameters, such as ring spacing (RS), ring width (RW) and ring number (RN), were deposited on the P- layer. The I–V measurement results show that breakdown voltages increase firstly and then decease with increasing of RS. The increases of RW and RN are beneficial to improve breakdown voltages. Moreover, FMRs structure can effectively improve breakdown voltages without deteriorating forward current density and rectification ratio of diamond SBDs.

According to the principle of metal-enhanced fluorescence (MEF), a localized surface plasmon resonance (LSPR) based method was used to develop a highly sensitive fluorescent aptasensor for detecting adenosine triphosphate (ATP). In this work, a polyAn-based special nucleic acid aptamers modified on gold nanoparticle (AuNPs) were hybridized with the FAM-labeled single-stand oligonucleotides. It was found that a great enhancement of fluorescence intensity in the nanostructures could be programmable regulated by adjusting the number of base A. The experiments showed the maximum enhancement for the fluorophore occurs when the polyAn length reached to 9 nm and, there was a good linear relationship between the fluorescence intensity and concentrations of ATP in the range of 0.5–1 nM. The detection limit obtained was 0.2 nM. Compared with the detection performances of traditional strategies, the sensitivity of the method was increased by more than 7 times, which make it hold great potential in bioanalytical and biological studies.

Bioelectrochemical systems (BESs) have been widely investigated for recalcitrant waste treatment mainly because of their waste removal effectiveness. Electroactive microbes (EMs) have long been thought to contribute to the high effectiveness by interacting with electrodes via electron chains. However, this work demonstrated the dispensable role of EMs for enhanced recalcitrant contamination degradation in BESs. We revealed enhanced p-fluoronitrobenzene (p-FNB) degradation in a BES by observing a defluorination efficiency that was three times higher than that in biodegradation or electrochemical processes. Such an improvement was achieved by the collaborative roles of electrode biofilms and planktonic microbes, as their individual contributions to p-FNB degradation were found to be similarly stimulated by electricity. However, no bioelectrochemical activity was found in either the electrode biofilms or the planktonic microbes during stimulated p-FNB degradation; because no biocatalytically reductive or oxidative turnovers were observed on cyclic voltammetry curves. The non-involvement of EMs was further proven by the similar microbial community evolution for biofilms and planktonic microbes. In summary, we proposed a mechanism for indirect electrical stimulation of microbial metabolism by electrochemically generating the active mediator p-fluoroaniline (p-FA) and further degradation by a sequential combination of electrochemical p-FNB reduction and biological p-FA oxidation by non-EMs.

The nitrogen vacancy (NV) center distribution in epitaxial lateral overgrowth (ELO) single crystal diamond layer grown on tungsten patterned HPHT substrate by microwave plasma chemical vapor deposition (CVD) system has been investigated. It has been found that in ELO diamond layer densities of NV0 and NV− center above the tungsten metal are enhanced. Meanwhile, in patterned high-pressure and high-temperature (HPHT) substrate the density of NV− center beneath the tungsten metal is much higher than that of NV0. The HPHT substrate does not contain NV centers before CVD growth, and there is almost no NV center in the region without tungsten metal after growth.

Direct determination of barrier height (ΦBH) value between Ir and single crystal (001) hydrogen-terminated diamond with lightly boron doped has been performed using x-ray photoelectron spectroscopy technique. 70 nm Ir islands were formed on hydrogen-terminated diamond surface using anodic aluminum oxide. The ΦBH value for lr/hydrogen-terminated diamond was -0.43 ± 0.14 eV, indicating that Ir was a suitable metal for ohmic contact with hydrogen-terminated diamond. The band diagram of lr/hydrogen-terminated diamond was obtained. The experimental ΦBH was compared with the theoretical ΦBH in this work.

Boron implanted edge terminations have been demonstrated to enhance the breakdown voltages and stabilities of diamond Schottky barrier diodes (SBDs). The edge terminations were achieved by boron implant to form nonconductive amorphous regions under the edges of the Schottky contacts. Direct current measurements show the implanted regions did not contribute to the forward currents and high current densities of about 4000 A/cm2 were obtained at −5 V. By using boron implanted edge terminations, although an increase in leakage currents was observed, the average breakdown voltage of the devices was significantly improved from 79 V to 125 V, which is increased by more than 50%. In addition, the breakdown voltages of the devices without edge terminations degraded quickly after each repeating measurement, whereas the devices with edge terminations became much more stable and no obvious drop in breakdown voltages was observed.

In this study, we report ultraviolet photoresponse enhancement of diamond photodetector by applying patterned diamond film design and two-step growth process. Diamond stripes are fabricated on the surface and interdigitated electrodes are set perpendicular to them. Before second step growth, surface defects induced during etching process affect the responsivity of supra-band gap light. After second step growth, the surface defects are suppressed, then the responsivity of photodetector on diamond strips are larger than that of photodetector on continuous diamond film. The larger responsivity could be attributed to the quasi-one-dimensional carrier transport and large surface to volume ratio. In additionally, a large electrode space is helpful in enhancing ultraviolet photoresponse while suppressing the visible response.

Sebastes schlegeliiis a commercially important fish with a special viviparous reproductive system that is cultured in near-shore seawater net cages in East Asia. In the gonadal development of the species, the gonad of males mature before those of females, which mature after mating. Mating in male/female fishes occurs in October of each year. Then, females undergoing oocyte maturation complete fertilization using stored sperm in March of the following year. The pregnancy is completed when larvae are produced in the ovary. It has been reported that embryonic nutrient supply originates entirely from the female viviparous reproductive systems. However, until now, the nutritional patterns and the processes of nutrient provision inS. schlegeliibefore parturition have not been clear. The goal of this research was to study the embryos, larvae and juveniles ofS. schlegeliiduring pregnancy. Anatomical observations, light microscopy and scanning electron microscopy were used to study the developmental characteristics of early embryos and larvae and the connecting structures between the mother and the fetus. The results showed the following: (1) Placental-like structures were found during the process of embryonic development inS. schlegelii, and these placental-like structures proliferated after fertilization. (2) The embryos ofS. schlegeliiwere encased by a saclike structure composed of blood vessels, connective tissue, and surface epithelial cells. The vessels near the embryo existed in the thecal layer. Vascularized proliferation was detected following embryonic development. (3) Starting in the gastrula stage, connections between the embryo and surrounding cells loosened, and ovarian fluid became abundant. In addition, a large number of small holes and cristae were observed on the surface of the embryo. We speculate that embryos may be able to absorb nutrients from the ovarian fluid. (4) Yolk was present throughout embryo development. (5) Two types of nutritional modes were observed, lecithotrophic and matrotrophic during embryonic development. Three forms of placental analogs may exist inS. schlegelii: (1) external epithelial absorptive surfaces; (2) trophonemata, with modifications of the ovarian epithelia for absorbing the histotroph; and (3) a follicular pseudoplacenta, with close apposition between follicle cells and embryonic absorptive epithelia.

The spatiotemporal distribution of fishing grounds in the Beibu Gulf and its relationship with marine environment were analyzed using the survey data of light falling-net vessels and satellite remote sensing data including sea surface temperature (SST), chlorophyll a concentration (Chl a) and net primary production (NPP), based on the generalized additive model (GAM) and the center of gravity (COG) of fishing grounds. The results showed that the total deviance explained by GAM for the catch per unit effort (CPUE) in the Beibu Gulf was 42.9%, in which SST was the most important influencing factor on CPUE, with a relative contribution of 40%, followed by latitude, Chl a, month and NPP, with relative contributions of 25.2%, 19%, 10.4% and 5.4%, respectively. Fishing grounds in the Beibu Gulf were mainly distributed in waters with SST of 27&ndash, 29 &deg, C, Chl a of 0.5&ndash, 1.5 mg&middot, m&minus, 3 and NPP of 500&ndash, 700 mg&middot, 2&middot, d&minus, 1. Light falling-net fishing grounds were concentrated in waters with latitude of 18.5&deg, N and 20&ndash, 20.25&deg, N. There was a significant correlation between the mean latitude of optimum NPP and the latitudinal COG of CPUE, with the R2 being 0.91. These were connected with environmental factors such as the northeast monsoon that began in autumn and winter, warm pools near 19&deg, N and local upwelling in the Beibu Gulf.

Fabrication of dual-termination Schottky barrier diode (SBDDT) by using oxygen-/fluorine-terminated diamond (OT-/FT-diamond) has been carried out on P-/P+ diamond. X-ray photoelectron spectroscopy (XPS) measurement was used to determine the chemical composition of OT-/FT-diamond surface treated by ultraviolet ozone and C4F8 plasma, respectively. The barrier heights of Au on OT-/FT-diamond were calculated to be 2.0 ± 0.12 and 2.39 ± 0.12 eV, respectively. Au film was patterned on the OT-/FT-diamond as the schottky electrode, and Ti/Au film were deposited on the backside of substrate as ohmic electrode, then a SBDDT was achieved completely. SBDDT exhibits better forward and reverse I-V characteristics based on the optimum OT-/FT-diamond (WO/WF) area ratio 0.2, which illustrates that the combination of dual surface termination is an efficient way to optimize the performance of diamond SBD.

Porous CoxNi1-xTa2O6 mesoporous nanomaterials were synthesized through a sol-gel route using the spray-dried method. They had high photocatalytic activity for water splitting into H2 and O2 under visible light. The X-ray diffraction (XRD) patterns of CoxNi1-xTa2O6 revealed that Co atoms could displace Ni atoms in the NiTa2O6 bulk lattice to form a solid solution. A field emission scanning electron microscope (FE-SEM, JSM-6700F) image showed that the microspheres were constructed of irregular nanoparticles randomly stacked to form a mesoporous structure. UV–Vis diffuse reflection spectroscopy (DRS) was used to determinate the band gap changes of CoxNi1-xTa2O6 samples, which extended towards the visible light region. However, the photocatalytic activity did not have a linear relationship with the band gap, even when the effect of the s urface area was considered. The distortion index of the TaO6 octahedral lattice was found to be an important influencing factor, and Co0.8Ni0.2Ta2O6 showed high photocatalytic efficiency with a maximum of 1367 μmol h−1 g−1 for H2 yield, which made it a promising candidate for splitting water.

The electrical properties, surface morphology and interface characteristics of W/p-diamond contact before and after annealing have been investigated. It is shown that the as-fabricated W/p-diamond contact exhibited non-linear behavior. After annealing at a temperature higher than 400 °C, the W/p-diamond contact showed ohmic behaviour. The specific contact resistance of W/p-diamond was 8.2 × 10−4 Ω·cm2 after annealing at 500 °C for 3 min in a N2 ambient, which was extracted from fitting the I-V relationship of TLM. It is noted that the RMS roughness increases with the annealing temperature increasing, which could be ascribed to the formation of WOX by the reaction of W and oxygen at high temperature. The XPS measurement showed that the barrier height of the W/p-diamond is 0.45 ± 0.12 eV after annealing at 500 °C. Furthermore, the formation of defects at the W/p-diamond interface, probably created by the formation of tungsten carbide during rapid thermal annealing, should be responsible for the ohmic formation of W/p-diamond after annealing at high temperature.

Epitaxial lateral overgrowth (ELO) of diamond films on patterned Ir/(0 0 1)HPHT-diamond substrates have been carried out by microwave plasma CVD system. Ir/(0 0 1)HPHT-diamond substrates are fabricated by photolithographic and magnetron sputtering technique. The morphology of the as grown ELO diamond film is characterized by optical microscopy and scanning electronic microscopy. The quality and stress of the ELO diamond film are investigated by surface etching pit density and micro-Raman spectroscopy. Two ultraviolet photodetectors are fabricated on ELO diamond area and non-ELO diamond area prepared on same substrate, and that one on ELO diamond area indicates better photoelectric properties. All results indicate quality of ELO diamond film is improved.

CdS/MoS2, an extremely efficient photocatalyst, has been extensively used in hydrogen photoproduction and pollutant degradation. CdS/MoS2 can be synthesized by a facile one-step hydrothermal process. However, the effect of the sulfur source on the synthesis of CdS/MoS2via one-step hydrothermal methods has seldom been investigated. We report herein a series of one-step hydrothermal preparations of CdS/MoS2 using three different sulfur sources: thioacetamide, l-cysteine, and thiourea. The results revealed that the sulfur source strongly affected the crystallization, morphology, elemental composition and ultraviolet (UV)-visible-light-absorption ability of the CdS/MoS2. Among the investigated sulfur sources, thioacetamide provided the highest visible-light absorption ability for CdS/MoS2, with the smallest average particle size and largest surface area, resulting in the highest efficiency in Methylene Blue (MB) degradation. The photocatalytic activity of CdS/MoS2 synthesized from the three sulfur sources can be arranged in the following order: thioacetamide>l-cysteine>thiourea. The reaction rate constants (k) for thioacetamide, l-cysteine, and thiourea were estimated to be 0.0197, 0.0140, and 0.0084min-1, respectively. However, thioacetamide may be limited in practical application in terms of its price and toxicity, while l-cysteine is relatively economical, less toxic and exhibited good photocatalytic degradation performance toward MB.

This paper investigates the regulation of the interior turbulent flow in a wet submersible motor using three-dimensional numerical simulation method based on ANSYS-CFD software. The model of the turbulent flow field between the rotor and the stator in the 850QS-3200 type wet submersible motor as an example was established to study the turbulent flow regulation of the axial-flow cooling water. The numerical investigation was carried out in wet submersible motor with different rotor outer surface roughness, i.e., 0.1, 0.3, 0.5, 0.7 and 0.9, with different rotor rotating speeds, i.e., 600, 1000, 1450, 1800, and 2200 r/min, and different flow rates of axial-flow cooling water, i.e., 0.5, 0.75, 1, 1.25 and 1.5 m/s. The distribution rules of the pressure, the absolute velocity and the velocity pathlines in the turbulent flow field were studied. The results show that these three factors have various different action mechanism and different degree of influence on the pressure distribution, absolute velocity distribution and velocity pathlines, which could provide a theoretical guide for the optimization of the rotor and stator system in wet submersible motor.

Fabrication of normally-off hydrogen-terminated diamond field-effect transistors (FET) has been carried out by using 3 nm Al2O3 dielectric layer, which was formed by thermally oxidizing 3 nm Al in air. 100 nm Al was covered on the 3 nm Al2O3 dielectric layer to form Al/Al2O3 gate. The leakage current density of FET with 6 μm gate length kept smaller than 5 × 10− 7 A·cm− 2, while the gate voltages swept from 3 to − 5 V. The capacitance-voltage characteristic indicated low-trapped charge densities in Al2O3 dielectric layer. For comparison, FET with only 3 nm Al2O3 gate and with 100 nm Al/3 nm Al2O3 gate was fabricated, which showed normally-on and normally-off characteristic respectively, indicating that 100 nm Al/3 nm Al2O3 gate could deplete hole densities in FET channel due to the difference of work function between Al and hydrogen-terminated diamond.

Enhancement of ultraviolet absorption through localized surface plasmon resonance (LSPR) was realized by assembling of Pd nanoparticles on homoepitaxial diamond thin films. The result of UV–vis spectrum of Pd nanoparticles embedded in diamond surface demonstrated the LSPR at wavelength of 213 nm, resulting in the improvement of ultraviolet absorption in diamond. The diamond ultraviolet photodetectors with and without Pd nanoparticles were fabricated and investigated. The results showed that the photoresponse from photodetector with Pd nanoparticles was 57.28 mA/W under 210 nm light at 5 V, which was three orders higher than that of detector without nanoparticles, and the UV/viable rejection ratio can reach to 4 orders of magnitude. This excellent performance should be attributed to LSPR in Pd nanoparticles, which was further confirmed by finite difference time domain (FDTD) simulation.

Fabrication of single crystal diamond microchannels on HPHT diamond substrate has been carried out successfully. Firstly, tungsten film was patterned on diamond substrate surface by conventional photolithography and magnetron sputtering methods. Secondly, single crystal diamond epitaxial layer was grown on the surface of the patterned substrate by microwave plasma chemical vapor deposition system. Then the tungsten film was etched out by acid to form microchannel. Finally, different color liquid was introduced to check the hollow of microchannels. The morphology of the microchannels has been investigated by optical microscope, scanning electron microscope and atomic force microscope. The crystallinity was evaluated by X-ray diffraction systems and Raman spectroscope technology.

Both anode potentials and substrates can affect the process of biofilm formation in bioelectrochemical systems, but it is unclear who primarily determine the anode-respiring bacteria (ARB) community structure and composition. To address this issue, we divided microbial electrolysis cells (MECs) into groups, feeding them with different substrates and culturing them at various potentials. Non-turnover cyclic voltammetry indicated that the extracellular electron transfer components were uniform when feeding acetate, because the same oxidation peaks occurred at - 0.36 ± 0.01 and - 0.17 ± 0.01 V (vs. Ag/AgCl). Illumina MiSeq sequencing revealed that the dominating ARB was Geobacter, which did not change with different potentials. When the MECs were cultured with sucrose and mixed substrates, oxidation peak P3 (- 0.29 ± 0.015 V) occurred at potentials of - 0.29 and 0.01 V. This may be because of the appearance of Unclassified_AKYG597. In addition, oxidation peak P4 (- 0.99 ± 0.01 V) occurred at high and low potentials (0.61 and - 0.45 V, respectively), and the maximum current densities were far below those of the middle potentials. Illumina MiSeq sequencing showed that fermentation microorganisms (Lactococcus and Sphaerochaeta) dominated the biofilms. Consequently, substrate primarily determined the dominating ARB, and Geobacter invariably dominated the acetate-fed biofilms with potentials changed. Conversely, different potentials mainly affected fermentable substrate-fed biofilms, with dominating ARB turning into Unclassified_AKYG59.

To better stabilize the hydrogen-terminated surface, a diamond based metal-insulator-semiconductor field-effect transistor with Zr-Si-N dielectric layer has been investigated. On the diamond epitaxial layer grown by microwave plasma chemical vapor deposition system, Pd films were patterned as the source and drain electrodes by photolithography and electron beam evaporation methods. Then, a Zr-Si-N dielectric layer and W metal film were fabricated as the gate structure by radio frequency magnetron sputtering technique. The device illustrates p-type depletion mode, in which the threshold voltage, maximum transconductance, drain current maximum, capacitance and dielectric constant were calculated to be 3.0V, 1.27mS/mm, -5.16 mA/mm, 0.275μF/cm2 and 7.8, respectively. The result suggest that Zr-Si-N dielectric layer is shown to have the ability to protect the two-dimensional hole gas.

Metal nitride hard coatings, such as TiN and TiAlN are widely used to protect materials because of their higher hardness and wear properties. However, these coatings always contain a high degree of internal stress which could arouse adhesion problems. It is hard to synthesize monolayer TiN or TiAlN coatings thicker than 10 μm by PVD (physical vapor deposition). The multilayer composite structure, offering efficient means of controlling residual stress, is a successful way to synthesize thicker hard coatings. In the present study, a series of multilayer composite Ti/TiN coatings with different composite periods were synthesized by plasma enhanced ion plating and the effects of multilayered structure mechanical properties of the coating was studied. The result shows that the mechanical properties of the coating are strengthened with increasing the periods of composite Ti/TiN layer. The micro hardness (HV0.25) can reach to about 27 500 MPa and better toughness and higher thickness (≥50 μm) are obtained. The toughness of the coating is almost directly proportional to hardness. Meanwhile, the tribological performance of the coating is improved with a lower dry friction coefficient (about 0.35) and higher wear resistance by alternating 48 periods of Ti/TiN layer. However, the bonding strength of the coating is weakened with further increasing the period of Ti/TiN layer due to the weak interface of coating and substrate.

Biodegradation of p-fluoronitrobenzene (p-FNB) regardless of effective p-FNB removal in a bioelectrochemical system (BES) was achieved for the first time in a biological system (BS). p-FNB degradation showed different kinetics, pathways, and microbial community evolutions in the two systems. About 36 d were required before 100% p-FNB removal in the BSp-FNB, while only 18 d were required in the BESp-FNB. Moreover, the reaction rate constant for p-FNB removal in the BESp-FNB was 1.625 times that in the BSp-FNB. The reduction of nitro groups was the key step for p-FNB removal in the BESp-FNB. However, defluorination was the first step for direct biodegradation of p-FNB in the BSp-FNB. Microbial community analysis showed that the dominant bacteria in the BESp-FNB (20.8% Anaerolineae, 15.9% Flavobacteriia, and 14.8% α-proteobacteria) differed greatly from those in the BSp-FNB (32.8% Flavobacteriia, 24.1% Clostridia and 19.2% Ignavibacteria). In the BSp-FNB, some aerobic microorganisms responsible for direct p-FNB biodegradation were enriched, while p-FA-degrading microorganisms were dominant in the BESp-FNB.

Anaerobic digestion is an alternative technology for the pretreatment of waste activated sludge (WAS) before final disposal. Hydrolysis is the rate-limiting step in this process; therefore, pretreatment of WAS to allow for high-efficiency anaerobic digestion is beneficial. In the present work, an electrochemical system characterized by a gas diffusion cathode (GDC) was established to facilitate WAS pretreatment. This GDC was composed of a carbon black diffusion layer and a Ni/NiOx catalytic layer. H2O2, an essential component of the pretreatment, was evolved on the electrode surface at a rate of 27.3 mg cm–2 day–1. Upon varying the potential of the GDC from 0 to −1.0 V (versus Ag/AgCl), the soluble chemical oxygen demand (SCOD) and the protein and carbohydrate concentrations increased from 134 ± 6, 38 ± 6, and 20 ± 3 mg/L to 3617 ± 65, 1436 ± 121, and 470 ± 64 mg/L, respectively, over 8 h. The ratio of SCOD to the total chemical oxygen demand (TCOD) was 48 ± 1.3%. The total methane output of the GDC pretr...

Submicron lenses and cylinders exhibiting excellent properties in photodetector and quantum applications have been fabricated on a diamond surface by an inductively-coupled plasma (ICP) etching technique. During ICP etching, a layer containing 500 nm diameter balls of SiO2 was employed as mask. By changing the mixing ratio of O2, Ar and CF4 during ICP etching, several submicron structures were fabricated, such as cylinders and lenses. The simulation results demonstrated that such submicron structures on a diamond&rsquo, s surface can greatly enhance the photon out-coupling efficiency of embedded nitrogen-vacancy center.

Purpose Taking a 2,000 r/min 10 kW permanent magnet motor as an example, the purpose of this paper is to study the influence of driving modes on the performance of permanent magnet motor at limit conditions, and researched the variation mechanism of motor performance influenced by different driving modes. Design/methodology/approach A two-dimensional electromagnetic field model of the permanent magnet motor was established, and a rectangular-wave driving circuit was built. By using the finite element method, the electromagnetic field, current, harmonic content and eddy current loss were calculated when the motor operated at rated load and limit load. On the basis of the motor loss calculation, the temperature field of the motor operating at rated condition and limit condition was researched, and the factors that influence motor limit overload capacity were analyzed. By analyzing the motor loss variation at different load conditions, the change mechanism of the motor temperature field was determined further. Combined with the related experiments, the correctness of the above analysis was verified. Findings Permanent magnet synchronous motor (PMSM) driven by sine wave is better compared with brushless direct current motor (BLDCM) driven by rectangular wave in reducing the magnetic field harmonics, motor losses and optimizing the temperature distribution in the motor. The method driven by sine wave could improve the motor output performance including the motor efficiency and the motor overload capacity. The winding temperature is the most important factor that limits the output capability of PMSM operating for a long time. However, because of the large rotor eddy current losses, the permanent magnet temperature is the most important factor that limits the output capability of BLDCM operating for a long time. Practical implications The influence of driving modes on the motor magnetic field, losses and temperature distribution, efficiency and overload capacity was determined, and the influence mechanism was also analyzed. Combined with the analysis of the electromagnetic and temperature fields, the advantages of different driving modes were presented. This study could provide an important basis for the design of permanent magnet motors with different driving modes, and it also provides reference for the application of permanent magnet motor. Originality/value This paper presents the influence of driving modes on permanent magnet motors. The limit output capacity of the motor with different driving modes was studied, and the key factors limiting the motor output capability were obtained.

Bacterial extracellular electron transfer is one of the main bottlenecks in determining the efficiency of bioelectrochemical systems. Here, we report a photobioanode that combines carbon material with a photocatalyst (α-Fe2O3), utilizing visible light to accelerate biofilm formation and extracellular electron transfer in bioelectrochemical systems. Cyclic voltammetric studies of this photobioanode revealed active electron transfer at the anode/biofilm interface. The charge-transfer resistance of the anode/biofilm was ca. 46.6 Ω, which is half that of the unmodified anode. In addition, the results of confocal laser scanning microscopy and bacterial community analysis indicate that the photobioanode and light can accelerate biofilm formation and enrich exoelectrogens. When equipped in photo-bioelectrochemical systems, the start-up time was shortened from about 2.5 days to 1.1 days. The maximum current density of photo-bioelectrochemical systems was almost twice that of a control bioelectrochemical system. In addition, the current density of the photo-bio-electrochemical cell (PBEC) showed almost no decrease after being subjected to 40 d of illumination. This photobioanode is therefore a cost-effective, energy-clean, environment-friendly anode with high electrocatalytic activity and long-term stability, which has broad prospects in various processes, including wastewater treatment, bioelectricity generation, bioelectricity synthesis, and hydrogen production.

This paper introduces a novel composite anode that uses light to enhance current generation and accelerate biofilm formation in bioelectrochemical systems. The composite anode is composed of 316L stainless steel substrate and a nanostructured α-Fe2O3 photocatalyst (PSS). The electrode properties, current generation, and biofilm properties of the anode are investigated. In terms of photocurrent, the optimal deposition and heat-treatment times are found to be 30 min and 2 min, respectively, which result in a maximum photocurrent of 0.6 A m−2. The start-up time of the PSS is 1.2 days and the maximum current density is 2.8 A m−2, twice and 25 times that of unmodified anode, respectively. The current density of the PSS remains stable during 20 days of illumination. Confocal laser scanning microscope images show that the PSS could benefit biofilm formation, while electrochemical impedance spectroscopy indicates that the PSS reduce the charge-transfer resistance of the anode. Our findings show that photo-electrochemical interaction is a promising way to enhance the biocompatibility of metal anodes for bioelectrochemical systems.

Flexible and amphiphobic alumina mats were fabricated by (heptadecafluoro-1, 1, 2, 2-tetradecyl)trimethoxysilane (FAS) modification of electrospun alumina mats. The alumina mats were obtained by the sol–gel method combined with an electrospinning process using aluminum nitrate nonahydrate (Al(NO3)3·9H2O) and aluminum isopropoxide (Al(C3H7O)3) as raw materials, nitric acid and acetic acid as catalysts, water as the solvent, and polyvinylpyrrolidone (PVP) was applied to tune sol viscosity. When the content of PVP was 1.3 wt%, the alumina mat after modification had higher water contact angle of 134° and oil contact angle of 122° than those with other concentrations. In addition, the alumina mat exhibited a hydrophobic property in the pH range from 1 to 14. The good stability of the prepared fiber mat in weak acidic and alkaline solution may extend its application in many industrial fields. Flexible and amphiphobic alumina mat was fabricated by modification of electrospun alumina mat, which was prepared by the sol–gel method combined with an electrospinning process.

NiFe2O4 microspheres were synthesized using a solvothermal method. The morphologies and structures of NiFe2O4 micropheres were characterized using a field emission scanning electron microscope(FESEM), a transmission electron microscope(TEM) and an X-ray diffractometer(XRD). The NiFe2O4 microspheres were around 150―200 nm in diameter and assembled by nanoparticles. The magnetic and electromagnetic parameters were measured using a vibrating sample magnetometer and a vector network analyzer, respectively. The obtained products exhibited a saturation magnetization of 60.8 A·m2·kg–1 at room temperature. A minimum reflection loss(RL) of–27.8 dB was observed at 9.2 GHz with a thickness of 3.5 mm, and the effective absorption frequency(RL

This paper designs and optimizes the cooling structure in deep well submersible motor, realizes the water circulation inside and outside of the submersible motor during the runtime. With setting up the temperature rise experimental platform that conforms to the operation mode in the deep well, the temperature rise of the submersible motor under the rated condition is measured. The effectiveness of water circulation cooling structure was verified. Finally, the successful application of this water cooling structure further proves that it is superiority. This cooling structure is simple and has great effects which avoids the problem of local high temperature, ensures the security and reliability of the submersible motor and enrich the drainage ways of deep well at the same time. This cooling structure this paper designed provide the beneficial reference for cooling structure in the similar submersible motor.

Localized surface plasmon-enhanced diamond UV photodetectors with different diameters of Pd nanoparticles (NPs) had been successfully fabricated. Four Pd NPs with diameters of 20, 40, 60, 70 nm were deposited on diamond surfaces, respectively, and their height was 20 nm. Ti/Ni/Au metal electrodes were patterned on samples surfaces to form UV photodetectors. According to photoelectric performance test results, responsivities were enhanced with sizes of particles increasing at UV region, and diamond photodetector with 40 nm NPs showed the highest photocurrent-to-dark current ratio and UV-to-visible rejection ratio. Compared with pure diamond photodetectors, the responsivity and UV/visible rejection ratio Pd modified detectors can improve up to 3250 and 34 times, respectively. Plasmonic scattering effect was used to explain this phenomenon, and it is further confirmed by the simulated scattering cross-section.

In this study, we fabricated and studied metal-oxide-semiconductor field effect transistors (MOSFETs) using bilayer Yb2TiO5/Al2O3 dielectrics on single crystal hydrogen-terminated diamond (H-diamond). Dielectric materials Yb2TiO5 and Al2O3 were deposited on H-diamond surface using radio frequency sputtering and atomic layer deposition, respectively. We point out that leakage current and hysteresis shift voltage of bilayer dielectric were three order of magnitude lower and one-third that of single layer Al2O3 dielectric, respectively. Based on capacitance-voltage characteristics dielectric constant, trapped charges and carrier hole density were evaluated for SD-Yb2TiO5/ALD-Al2O3 and ALD-Al2O3 MOSFET's. The effective mobility for Yb2TiO5/Al2O3 sample evaluated by using the relation between on-state resistance and 1/|VGS-VTH|was 102.4 cm2.V−1.s−1.

The characteristics of ruthenium (Ru) contact to boron doped diamond (BDD) have been investigated before and after annealing. The properties of as-deposited Ru contacts to BDD showed non-linear trend. Interestingly, the contact properties of Ru/BDD exhibited ohmic contact behavior after post-annealing at 500 °C. The specific contact resistance (ρc) of Ru/BDD was 2.3 × 10−4 Ω·cm2 after annealing at 500 °C for 20 min in the argon (Ar) ambient. The contact barrier height was 0.075 eV ± 0.14 eV after annealing at 500 °C, evaluated by X-ray photoelectron spectroscopy (XPS).

The fabrication of a single-crystal hydrogen-terminated diamond metal-oxide-semiconductor field-effect transistor (MOSFET) with HfSiON/Al2O3 bilayer dielectric has been carried out. HfSiON and Al2O3 layers were deposited by sputtering-deposition (SD) and atomic layer deposition (ALD) techniques. The maximum output current for SD-HfSiON/ALD-Al2O3 was 36 mA mm−1, and for ALD-Al2O3, it was 31 mA mm−1. We reported that the hysteresis shift voltage of the bilayer dielectric MOSFET was one fourth of the single dielectric layer MOSFET. The leakage current density of SD-HfSiON/ALD-Al2O3 was one order of magnitude lower than the single layer dielectric. We also determined the dielectric constants of HfSiON/Al2O3 and Al2O3 dielectrics based on capacitance–voltage characteristics. The values of VTH, on/off ratio, subthreshold swing, and low field mobility for the bilayer dielectric MOSFET were evaluated to be 4.5 V, 105, 296 mV/decade, and 154 cm2 V−1 s−1, respectively.

Fabrication of microlenses on a diamond surface is an important way to enhance the performance of the embedded nitrogen vacancy (NV) center which is a promising single light source for quantum communication and quantum-based detection. In this work, lenses with a micrometer diameter were fabricated on a diamond surface by using the inductively coupled plasma (ICP) etching technique with a mask of polystyrene (PS) balls. First, 1 µm diameter PS balls were dispersed on the surface of deionized water. Then, the balls were transferred onto a diamond surface. Third, the sample was treated using the ICP technique to form microlenses. By increasing ICP etching time, the surface of fabricated microlenses became smoother. The simulation results demonstrate that the microlenses can greatly improve the photon collection efficiency of the embedded NV center and focus more excitation light to the NV center than bulk diamond.

In this study, a Ti–diamond–Ti structured ultraviolet photodetector was fabricated on a homoepitaxial diamond layer with an oxygen-terminated surface. The properties of the Ti/diamond schottky contact were measured using X-ray photoelectron spectroscopy, and the barrier height was found to be 1.15 eV. At a bias of 3 V, the responsivity at 210 nm was only 4.29 mA/W, while at 12 V, the responsivity increased rapidly to 51 mA/W. The increase can be ascribed to the photocurrent gain. With the further increase in voltage, an avalanche effect was produced, and the responsivity could reach 1.18 A/W at 50 V. Moreover, the transient response behavior of the photodetector exhibited a good repeatability and response speed.

A growth of single crystal diamond (SCD) microchannels on HPHT diamond substrate has been carried out successfully by a simple and novel method. Firstly, aluminum film was patterned on SCD diamond substrate surface by magnetron sputtering, photolithography and dry etching techniques. Secondly, the aluminum patterns were transferred onto diamond substrate via inductively coupled plasma etching to form grooves on diamond surface. Finally, microchannels were achieved by epitaxial lateral overgrowth of SCD on the surface of prepared substrate by microwave plasma chemical vapor deposition system. After that, fluorescent liquid was introduced to check hollowness of the microchannels. This work provides a simple and time saving method to fabricate SCD microchannels for microfluidic system, which offers a great potential for hard environment applications.

With the increase of antibiotic resistances in microorganisms, photodynamic inactivation (PDI) as a clinically proven antibacterial therapy is gaining increasing attention in recent years due to its high efficacy. Herein, we reported two covalent organic frameworks (COFs) materials, namely COFs-Trif-Benz and COF-SDU1, as effective type-II photosensitizers for photodynamic inactivation of bacteria. COFs-Trif-Benz and COF-SDU1 are synthesized through a facile solvothermal reaction between tri-(4-formacylphenoxy)-1,3,5-triazine (trif) and benzidine or p-phenylenediamine with high yield. Their highly ordered and porous structures were confirmed by Fourier transform infrared (FT-IR) spectra, solid state 13C CP/MAS NMR spectrum, powder X-ray diffraction (PXRD) and Brunauer–Emmett–Teller (BET) analyses. The electronic absorption spectra and electrochemical experiments revealed that the extensive π-conjugation over COFs-Trif-Benz and COF-SDU1 greatly enhance their absorbance capability for visible light and make them have a lower band gap. The photocatalytic antibacterial assay was studied against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli O86:B7 (E. coli O86) bacteria. Two materials can kill more than 90% bacteria at concentrations of 100 μg mL− 1 after 60–90 min of illumination. Thus, both COFs are effective photosensitizers. Mechanism investigation revealed the antibacterial characteristics of the COFs-Trif-Benz and COF-SDU1 can generate reactive oxygen species (ROS) by energy transfer to molecular oxygen (3O2) to produce a highly reactive singlet oxygen (1O2). Hence, the two materials during the photodynamic were mainly via mechanism type II.

A hundreds of microns three-dimensional single crystal diamond (SCD) channel along with high aspect ratio has been fabricated successfully by two-step process. Firstly, laser machining technique was used to produce trenches in high-temperature high-pressure SCD substrate. Then, microchannels were achieved by epitaxial lateral overgrowth of diamond layer on patterned substrate by microwave plasma chemical vapor deposition system. Dimensional variations and crystalline quality around the microchannel cross section were analyzed using scanning electron microscopy and Raman spectroscopy. The hollowness and continuity of microchannels were also be tested. It is a significant step towards fabrication of hundreds of microns SCD channel along with controlled high aspect ratio by a simple and controllable way.

Fabrication of single crystal hydrogen-terminated diamond MOSFET with YSZ/Al2O3 bilayer dielectrics has been successfully carried out. The flat band voltage shift and hysteresis voltage were small in the capacitance-voltage curve. The dielectric constant of YSZ/Al2O3 was calculated, and the fixed and trapped charge densities in dielectrics were deduced based on the capacitance-voltage curve. According to the transfer characteristics curve, on/off ratio and breakdown voltage were extracted. Distinct pinch-off and p-type channel were shown in the output characteristics curve. The effective mobility was evaluated to be 80.4 cm2 V−1 s−1 at VGS = −1.5 V based on the relation between on-state resistance and 1/|VGS-VTH|.

To verify the potentially synthetic anodic and cathodic biocatalysis mechanism in bioelectrocatalysis systems (BECSs), a single-chamber thermophilic bioelectrocatalysis system (R3) was operated under strictly anaerobic conditions using the biocathode donated dual-chamber (R1) and bioanode donated dual-chamber (R2) BECSs as controls. Direct bioelectrocatalytic oxidation was found to be infeasible while bioelectrocatalytic reduction was the dominant process for p-Fluoronitrobenzene (p-FNB) removal, with p-FNB removal of 0.188 mM d(-1) in R1 and 0.182 mM d(-1) in R3. Cyclic voltammetry experiments confirmed that defluorination in the BECSs was an oxidative metabolic process catalyzed by bioanodes following the reductive reaction, which explained the 0.034 mM d(-1) defluorination in R3, but negligible defluorination in controls. Taken together, these results revealed a sequentially combined reduction and oxidation mechanism in the thermophilic BECS for p-FNB removal. Moreover, the enrichment of Betaproteobacteria and uniquely selected Bacilli in R3 were probably functional populations for p-FNB degradation.

In this study, diamond pseudo-vertical architecture Schottky barrier diodes (PVSBDs) through the patterning tungsten growth method have been investigated. The forward current density is 16 A/cm2 at 5 V, and a rectification ratio is more than 5 orders of magnitude at ±5 V for diamond PVSBD. The reverse breakdown voltage is 640 V, and the corresponding electrical field is 4.57 MV/cm. These results are obtained by patterning tungsten (W) on the diamond surface as a blocking layer and growing a diamond epitaxial layer on the uncovered zone. A W/diamond ohmic contact was formed during the diamond epitaxial layer growth process. An aluminum film was used as a Schottky contact. Overall, the results illustrate that W patterned growth to fabricate PVSBD is efficient.

In this study, a NiO/diamond UV-photodetector has been fabricated and investigated. A single crystal diamond (SCD) layer was grown on a high-pressure-high-temperature Ib-type diamond substrate by using a microwave plasma chemical vapor deposition system. NiO films were deposited directly by the reactive magnetron sputtering technique in a mixture gas of oxygen and argon onto the SCD layer. Gold films were patterned on NiO films as electrodes to form the metal-semiconductor-metal UV-photodetector which shows good repeatability and a 2 orders of magnitude UV/visible rejection ratio. Also, the NiO/diamond photodetector has a higher responsivity and a wider response range in contrast to a diamond photodetector.