Direct growth of doping controlled monolayer WSe2 by selenium-phosphorus substitution.

Although many studies have been carried out on the doping of transition metal dichalcogenides (TMDCs), introducing controllable amounts of dopants into a TMD lattice is still insufficient. Here we demonstrate doping controlled TMDC growth by the replacement of selenium with phosphorus during the synthesis of the monolayer WSe2. The phosphorus doping density was precisely controlled by fine adjustment of the amount of P2O5 dopant powder along the pre-annealing time. Raman spectroscopy, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and high-angle annular bright field scanning tunneling electron microscopy (HAADF STEM) provide evidence that P doping occurs within the WSe2 crystal with P occupying the substitutional Se sites. With regard to its electrical characteristics, the hole majority current of P-doped WSe2 is 100-times higher than that of the intrinsic WSe2. The measured doping concentration ranged from ∼8.16 × 1010 to ∼1.20 × 1012 depending on the amount of P2O5 dopant powder by pre-annealing.

Herbal medicines for treating acute otitis media: A systematic review of randomised controlled trials.

INTRODUCTION: This systematic review aimed to assess the clinical evidence for the widespread use of herbal medicines in treating acute otitis media. METHODS: Eleven electronic databases, including MEDLINE, EMBASE, and the CENTRAL were searched, without language limitations. All randomised controlled trials involving the use of herbal medicines, alone or in combination with conventional therapies, for acute otitis media were included. RESULTS: We identified 4956 studies, of which seven randomised clinical trials met the inclusion criteria. The overall risk of bias of the included trials was relatively high or unclear. Treatment with Longdan-xiegan decoction or Shenling-baizhu powder, combined with antibiotics, appeared to be more effective than treatment with antibiotics alone in terms of the proportion of patients with total symptom recovery. Moreover, combination treatment of Sinupret® and antibiotics facilitated the recovery of middle ear conditions and hearing acuity. CONCLUSIONS: Despite some indications of potential symptom improvement, the evidence regarding the effectiveness and efficacy of herbal medicine for acute otitis media is inconclusive due to the poor quality of trials included. Moreover, we only analysed seven trials in this review. Therefore, to properly evaluate the effectiveness of herbal medicine for acute otitis media, systematic reviews based on more rigorously designed randomized trials are warranted in the future.

Fabrication and Characteristics of High Capacitance Al Thin Films Capacitor Using a Polymer Inhibitor Bath in Electroless Plating Process.

An aluminum (Al) thin film capacitor was fabricated for a high capacitance capacitor using electrochemical etching, barrier-type anodizing, and electroless Ni-P plating. In this study, we focused on the bottom-up filling of Ni-P electrodes on Al2O3/Al with etched tunnels. The Al tunnel pits were irregularly distributed on the Al foil, diameters were in the range of about 0.5~1 µm, the depth of the tunnel pits was approximately 35~40 µm, and the complex structure was made full filled hard metal. To control the plating rate, the experiment was performed by adding polyethyleneimine (PEI, C2H5N), a high molecular substance. PEI forms a cross-link at the etching tunnel inlet, playing the role of delaying the inlet plating. When the PEI solution bath was used after activation, the Ni-P layer was deposited selectively on the bottoms of the tunnels. The characteristics were analyzed by adding the PEI addition quantity rate of 100~600 mg/L into the DI water. The capacitance of the Ni-P/Al2O3 (650~700 nm)/Al film was measured at 1 kHz using an impedance/gain phase analyzer. For the plane film without etch tunnels the capacitance was 12.5 nF/cm2 and for the etch film with Ni-P bottom-up filling the capacitance was 92 nF/cm2. These results illustrate a remarkable maximization of capacitance for thin film metal capacitors.

Effect of Liquid Media on the Formation of Multi-Layer Graphene-Synthesized Metal Particles.

We report a simple approach for the production of copper nanoparticles by a wire explosion process that creates different structures in deionized (DI) water versus isopropyl alcohol (IPA) liquid media. In DI water, copper nanoparticles (CNs) are formed, while multi-layer graphene-synthesized copper nanoparticles (MGCNs) with a high degree of graphitization are formed in the IPA liquid media. The nanoparticles have an average diameter ranging from 10 nm to 300 nm and a quasi-spherical morphology. The morphologies and sizes of nanoparticles formed via this method were characterized by high-resolution transmission electron microscopy (HRTEM), field-emission scattering electron microscopy (FESEM), and analysis of dynamic light scattering (DLS). The microstructures and chemical bonding of the nanoparticles were studied by X-ray diffraction (XRD), Raman spectra measurement, and X-ray photoelectron spectroscopy (XPS). This results show an easily reproducible way to synthesize metal-core nanoparticles with multi-layer graphene shells based onto the liquid media used during synthesis. These materials can be used in the field of energy storage and as additives in the near future.

Power Enhancement of Lithium-Ion Batteries by a Graphene Interfacial Layer.

We achieved a method for power enhancement of heavy-duty lithium-ion batteries (LIBs) by synthesizing a graphene interfacial layer onto the anode copper current collector (ACCC). We tested fabricated coin cells, which used either 35-µm-thick rolled pristine copper foil or graphene synthesized onto the pristine copper foil for power output estimation of the LIBs. We observed the copper surface morphology with a scanning electron microscope (SEM). Raman spectroscopy was used to measure the bonding characteristics and estimate the layers of graphene films. In addition, transmittance and electrical resistance were measured by ultra-violet visible near-infrared spectroscopy (UV-Vis IR) and 4 point probe surface resistance measurement. The graphene films on polyethylene terephthalate (PET) substrate obtained a transmittance of 97.5% and sheet resistance of 429 Ω/square. Power enhancement performances was evaluated using LIB coin cells. After 5C current discharge rate of -1.7 A/g reversible capacity of 293 mAh/g and 326 mAh/g were obtained for pristine and synthesized graphene anode current collectors, respectively. The graphene synthesized onto the ACCC showed superior power performance. The results presented herein demonstrate a power enhancement of LIBs by a decrease in electron flow resistivity between active materials and the ACCC and removal of the native oxide layer on the anode copper surface using high quality graphene synthesized onto the ACCC.

Electroless nickel alloy deposition on SiO2 for application as a diffusion barrier and seed layer in 3D copper interconnect technology.

Electroless Ni-P films were investigated with the aim of application as barrier and seed layers in 3D interconnect technology. Different shapes of blind-via holes were fabricated with a deep reactive ion etcher and SiO2 formed on these holes as an insulating layer. The surface of the substrate has been made hydrophilic by O2 plasma treatment with 100 W of power for 20 min. Electroless Ni-P films were deposited as both a diffusion barrier and a seed layer for Cu filling process. Prior to plating, substrates were activated in a palladium chloride solution after sensitization in a tin chloride solution with various conditions in order to deposit uniform films in TSV. After the formation of the electroless barrier layer, electro Cu was plated directly on the barrier layer. Ni-P films fabricated in blind-via holes were observed by scanning electron microscope. Energy dispersive spectroscopy line scanning was carried out for evaluating the diffusion barrier properties of the Ni-P films. The electroless Ni-P layer worked well as a Cu diffusion barrier until 300 degrees C. However, Cu ions diffused into barrier layer when the annealing temperature increases over 400 degrees C.

Roll-to-roll production of 30-inch graphene films for transparent electrodes.

The outstanding electrical, mechanical and chemical properties of graphene make it attractive for applications in flexible electronics. However, efforts to make transparent conducting films from graphene have been hampered by the lack of efficient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications. Here, we report the roll-to-roll production and wet-chemical doping of predominantly monolayer 30-inch graphene films grown by chemical vapour deposition onto flexible copper substrates. The films have sheet resistances as low as approximately 125 ohms square(-1) with 97.4% optical transmittance, and exhibit the half-integer quantum Hall effect, indicating their high quality. We further use layer-by-layer stacking to fabricate a doped four-layer film and measure its sheet resistance at values as low as approximately 30 ohms square(-1) at approximately 90% transparency, which is superior to commercial transparent electrodes such as indium tin oxides. Graphene electrodes were incorporated into a fully functional touch-screen panel device capable of withstanding high strain.

Wafer-scale synthesis and transfer of graphene films.

We developed means to produce wafer scale, high-quality graphene films as large as 3 in. wafer size on Ni and Cu films under ambient pressure and transfer them onto arbitrary substrates through instantaneous etching of metal layers. We also demonstrated the applications of the large-area graphene films for the batch fabrication of field-effect transistor (FET) arrays and stretchable strain gauges showing extraordinary performances. Transistors showed the hole and electron mobilities of the device of 1100 +/- 70 and 550 +/- 50 cm(2)/(V s) at drain bias of -0.75 V, respectively. The piezo-resistance gauge factor of strain sensor was approximately 6.1. These methods represent a significant step toward the realization of graphene devices in wafer scale as well as application in optoelectronics, flexible and stretchable electronics.

Temperature effects on the aerobic metabolism of glycogen-accumulating organisms.

Short-term temperature effects on the aerobic metabolism of glycogen-accumulating organisms (GAO) were investigated within a temperature range from 10 to 40 degrees C. Candidatus Competibacter Phosphatis, known GAO, were the dominant microorganisms in the enriched culture comprising 93 +/- 1% of total bacterial population as indicated by fluorescence in situ hybridization (FISH) analysis. Between 10 and 30 degrees C, the aerobic stoichiometry of GAO was insensitive to temperature changes. Around 30 degrees C, the optimal temperature for most of the aerobic kinetic rates was found. At temperatures higher than 30 degrees C, a decrease on the aerobic stoichiometric yields combined with an increase on the aerobic maintenance requirements were observed. An optimal overall temperature for both anaerobic and aerobic metabolisms of GAO appears to be found around 30 degrees C. Furthermore, within a temperature range (10-30 degrees C) that covers the operating temperature range of most of domestic wastewater treatment systems, GAOs aerobic kinetic rates exhibited a medium degree of dependency on temperature (theta = 1.046-1.090) comparable to that of phosphorus accumulating organisms (PAO). We conclude that GAO do not have metabolic advantages over PAO concerning the effects of temperature on their aerobic metabolism, and competitive advantages are due to anaerobic processes.

Flexible transparent conducting single-wall carbon nanotube film with network bridging method.

We fabricated random network films of highly pure single-wall carbon nanotubes (SWCNTs) on flexible polyethylene terephthalate substrate by dip- and spray-coatings and their combination method for application to flexible transparent conducting films (TCFs). The dip-coating treatment was a more efficient method for fabricating the SWCNT-TCFs of high electrical conductivity without drastic drop in the optical transmittance, compared to the spray-coating one. This should be primarily due to more loose contact in intertube and interbundle junctions of the spray-coated SWCNT networks. Although the electrical conductivity of the SWCNT-TCFs was dramatically enhanced as increasing the number of dipping times, the dip-coating treatment with a large number of dipping times considerably reduced the transmittance without corresponding improvement in the electrical conductivity, indicating the patch-wise coating of the SWCNTs. On the other hand, the combination of the spray- and dip-coatings gave a supplementary effect for formation of a highly transparent film of better electrical conductivity. For SWCNT-TCF coated with 100 dipping times, an additional spray-coating dramatically decreased the sheet resistance from 1300 to 340 Omega/square, which is accompanied by slight reduction of the transmittance from 88 to 80%. Therefore, the post spray-coating can efficiently bridge the patch-wise SWCNT networks produced by the successive dip-coating.

Short-term temperature effects on the anaerobic metabolism of glycogen accumulating organisms.

Proliferation of glycogen accumulating organisms (GAO) has been identified as a potential cause of enhanced biological phosphorus removal (EBPR) failure in wastewater treatment plants (WWTP). GAO compete for substrate with polyphosphate accumulating organisms (PAO) that are the microorganisms responsible for the phosphorus removal process. In the present article, the effects of temperature on the anaerobic metabolism of GAO were studied in a broad temperature range (from 10 to 40 degrees C). Additionally, maximum acetate uptake rate of PAO, between 20 and 40 degrees C, was also evaluated. It was found that GAO had clear advantages over PAO for substrate uptake at temperatures higher than 20 degrees C. Below 20 degrees C, maximum acetate uptake rates of both microorganisms were similar. However, lower maintenance requirements at temperature lower than 30 degrees C give PAO metabolic advantages in the PAO-GAO competition. Consequently, PAO could be considered to be psychrophilic microorganisms while GAO appear to be mesophilic. These findings contribute to understand the observed stability of the EBPR process in WWTP operated under cold weather conditions. They may also explain the proliferation of GAO in WWTP and thus, EBPR instability, observed in hot climate regions or when treating warm industrial effluents. It is suggested to take into account the observed temperature dependencies of PAO and GAO in order to extend the applicability of current activated sludge models to a wider temperature range.