Interface modification of cathode electrode using dimmethyldicyanoquinonediimine as a charge transfer layer in organic photovoltaic cell

Various metals for the cathode electrode of organic electronic devices have been used in order to improve carrier injection and contact resistance etc. However, metal electrodes have some disadvantages such as rough surfaces, inadequate interfacial durability and unsuitable work functions. In the present work, we have fabricated an organic photovoltaic cell consisting of ITO/PEDOT:PSS/P3HT:PCBM/DMDCNQI/Al. The dimmethyldicyanoquinonediimine (DMDCNQI) compound was used as an organic n-type charge transfer complex between the cathode electrode and an organic active layer to improve contact resistance and electron transport ability. The prepared device shows a high short-circuit current density of 10.39 mA/cm2 and a maximum power conversion efficiency of 3.10%.     

Experimental investigation on two-phase flow boiling heat transfer of five refrigerants in horizontal small tubes of 0.5, 1.5 and 3.0 mm inner diameters

An experimental investigation on two-phase flow boiling heat transfer with refrigerants of R-22, R-134a, R-410A, C₃H₈ and CO₂ in horizontal circular small tubes is presented. The experimental data were obtained over a heat flux range of 5–40 kW m^?2, mass flux range of 50–600 kg m^?2 s^?1, saturation temperature range of 0–15 °C, and quality up to 1.0. The test section was made of stainless steel tubes with inner diameters of 0.5, 1.5 and 3.0 mm, and lengths of 330, 1000, 1500, 2000 and 3000 mm. The experimental data were mapped on Wang et al. (1997) [5] and Wojtan et al. (2005) [6] flow pattern maps. The effects of mass flux, heat flux, saturation temperature and inner tube diameter on the heat transfer coefficient are reported. The experimental heat transfer coefficients were compared with some existing correlations. A new boiling heat transfer coefficient correlation that is based on a superposition model for refrigerants in small tubes is presented with 15.28% mean deviation and ?0.48% average deviation.     

Hydrothermal synthesis of layered sodium manganese oxide nanowires and their electrochemical performance

A new method for preparing black birnessite nanowires is introduced. Layer-structured manganese oxide nanowires were synthesized by a facile hydrothermal method, and using both NaMnO4 and CH3CH2OH as the precursors in a concentrated NaOH solution. The structure, composition, appearance and electrochemical performance of the product were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), energy diffraction (ED), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA) and constant current charge/discharge. The XRD patterns showed a single phase corresponding to a crystalline birnessite-based manganese oxide. TEM studies suggested their wire-like structures. The TGA measurement demonstrated that they possessed an excellent thermal stability up to 400 degrees C. In the potential window of 2.0-4.3 V, the product exhibited excellent cyclic stability and rapid charge-discharge performance.     

Nitride precipitation in salt-bath nitrided interstitial-free steel

Nitride precipitation and its effect on microstrain in salt-bath nitrided interstitial-free steel were investigated using transmission electron microscopy and neutron diffraction. As the cooling rate after nitriding decreased, two nitrides, γ′-Fe₄N and α"-Fe₁₆N₂, were identified in diffusion zone. Combined analyses using Rietveld whole-profile fitting and size–strain analysis revealed that the microstrain in the nitrided specimen increased due to nitrogen supersaturation and then decreased after nitride precipitation, whereas the effective particle size continuously decreased. It was found that microstrain is the dominant factor in peak broadening of the nitrided specimen.     

Shape‐Dependent Cytotoxicity and Proinflammatory Response of Poly(3,4‐ethylenedioxythiophene) Nanomaterials

Poly(3,4‐ethylenedioxythiophene) (PEDT) is recognized as one of the most promising conducting polymers for future applications in the fields of electronics, optics, energy storage/conversion, and biomedical science. The toxicity of PEDT could be considered to affect the potential for its widespread application. Herein, the cytotoxicity and proinflammatory response of PEDT nanomaterials of three different shapes toward human lung fibroblast (IMR90) and mouse alveolar macrophage (J774A.1) cells are investigated. The shape‐dependent toxicity of the PEDT nanomaterials is evaluated by examining cell morphological change, cytotoxicity, apoptosis/necrosis, oxidative stress, and immune response. The cytotoxicity and apoptosis of the nanomaterials increase with their decreasing aspect ratio in both cell lines. The formation of reactive oxygen species in cells treated with PEDT nanomaterials is dependent on the shape and concentration of the nanomaterial. Proinflammatory cytokines, such as interleukin‐1, interleukin‐6, and tumor necrosis factor α from macrophages, are induced by PEDT nanomaterial‐treated cells.     

Micromagnetic Simulation of Damped Oscillatory Behavior of Domain Wall Propagation in Sinusoidal Ferromagnetic Nanowire

We have investigated a damped oscillatory behavior of domain wall propagation in wavy nanowires under an external field higher than the Walker breakdown field using micromagnetic simulation. In nanowires having sinusoidal edge distortions with variation of wavelengths, domain wall has been observed to pseudomorphically follow the sinusoidal wires with keeping an intrinsic transformational frequency of inner wall spin structure. Oscillation amplitude of the domain wall position decreases as the wavelength of the wire decreases by an interaction between the periodically distributed spins and the propagating domain wall. Oscillatory behavior of the domain wall position is found to decay in a wire having the wavelength well matching with an intrinsic transformational frequency of the propagating domain wall.      

Measurements of neutron total cross-sections and resonance parameters of erbium at the Pohang Neutron Facility

We measured neutron total cross-sections of natural erbium in the neutron energy region from 0.2 to 120 eV by using the neutron time-of-flight method at the Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled tantalum target with a water moderator, and a 12-m-long time-of-flight path. A ⁶Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm was used as a neutron detector, and a group of high-purity natural erbium metallic plates with various thickness was used for the neutron transmission measurements. The present measurement was compared with the existing experimental and the evaluated data. The resonance parameters of ¹⁶⁶Er, ¹⁶⁷Er, ¹⁶⁸Er, and ¹⁷⁰Er in the neutron energy region below 120 eV were extracted from the transmission by using the multilevel R-matrix SAMMY code and were compared with the evaluated data from ENDF/B VII.0 and other previous reported results.     

Commissioning of the first KSTAR neutral beam injection system and beam experiments

The neutral beam injection (NBI) system was designed to provide plasma heating and current drive for high performance and long pulse operation of the Korean Superconducting Tokamak Advanced Research (KSTAR) device using two co-current beam injection systems. Each neutral beam injection system was designed to inject three beams using three ion sources and each ion source has been designed to deliver more than 2.0 MW of deuterium neutral beam power for the 100-keV beam energy. Consequently, the final goal of the KSTAR NBI system aims to inject more than 12 MW of deuterium beam power with the two NBI for the long pulse operation of the KSTAR. As an initial step toward the long pulse (～300 s) KSTAR NBI system development, the first neutral beam injection system equipped with one ion source was constructed for the KSTAR 2010 campaign and successfully commissioned. During the KSTAR 2010 campaign, a MW-deuterium neutral beam was successfully injected to the KSTAR plasma with maximum beam energy of 90 keV and the L-H transition was observed with neutral beam heating. In recent 2011 campaign, the beam power of 1.5 MW is injected with the beam energy of 95 keV. With the beam injection, the ion and electron temperatures increased significantly, and increase of the toroidal rotation speed of the plasma was observed as well. This paper describes the design, construction, commissioning results of the first NBI system leading the successful heating experiments carried in the KSTAR 2010 and 2011 campaign and the trial of 300-s long pulse beam extraction.     

Short communication: Variability in milk urea nitrogen and dairy total mixed ration composition in the northeastern United States

The main objective of this survey was to examine variability in milk urea nitrogen (MUN) for Dairy Herd Improvement Association (DHIA) herds in the northeastern United States (the Northeast), examine trends in dairy cow diet composition, and determine potential relationships for MUN and diet composition. Trends in milk fat and protein concentrations, milk yield, days in milk on test day, and lactation number of the cows were also evaluated. The data set for the survey included 10,839,461 DHIA dairy cow records from 2004 to 2015 for 13 states (CT, DE, MA, MD, ME, NH, NJ, NY, PA, RI, VA, VT, and WV) and was retrieved from Dairy Records Management Systems (Raleigh, NC). Average (across states and years) milk yield, milk fat, and milk protein were 31.6 ± 0.24 kg/d, 3.85 ± 0.021%, and 3.13 ± 0.013%, respectively. No obvious trends were observed for milk fat or protein content, but milk yield steadily increased during the survey period. Milk urea N concentration averaged 13.3 ± 0.13 mg/dL, with no obvious or consistent trends. Examination of variability in dairy feed cost and all milk price for the Northeast indicated that high MUN generally coincided with high feed cost and high milk price. For the diet composition survey, 9,707 records of total mixed ration (TMR) analyses, unrelated to the milk composition data set, from the Cumberland Valley Analytical Service (Maugansville, MD) database were examined. Concentration of TMR crude protein (CP) decreased from 17.1% in 2007 to 16.4% in 2015, but there was not an obvious trend in soluble protein concentration. Concentration of TMR neutral detergent fiber (NDF) and 24-h in vitro NDF degradability declined steadily during the survey period and was accompanied by a steady increase in TMR starch concentration. Examination of these unrelated data sets revealed lack of correlation between MUN and diet chemical composition. Thus, we conclude that individual cow MUN in Northeast dairy herds fluctuated between 2004 and 2015. It appeared that MUN followed variability in feed cost; however, ration feed ingredient data were not available to better define the reasons for the variations in MUN.