Development of an Aerosol Dynamics Model for Dry Deposition Process Using the Moment Method

An aerosol dynamics model for dry deposition process is developed based on the moment method. Since it is hard to fully apply the moment method to the widely used dry deposition velocity expressions based on the resistance theory, the dry deposition velocity expression by Raupach et al. (2001) Raupach, M. R., Briggs, P. R., Ahmad, N. and Edge, V. E. 2001. Endosulfan Tansport: II. Modeling airborne Dispersal and Deposition by Spray and Vapor. J. Environ. Qual., 30: 729–740. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] is used. Detailed deposition mechanisms such as Brownian diffusion, gravitational settling, and impaction are considered in the expression. To verify the validity of the derived dynamic equation, aerosol dynamics for the dry deposition process is estimated with the expressions of Raupach et al. (2001) Raupach, M. R., Briggs, P. R., Ahmad, N. and Edge, V. E. 2001. Endosulfan Tansport: II. Modeling airborne Dispersal and Deposition by Spray and Vapor. J. Environ. Qual., 30: 729–740. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar], of Wesely (1989) Wesely, M. L. 1989. Parameterizations of Surface Resistance to Gaseous Dry Deposition in Regional-Scale, Numerical Models. Atmos. Environ., 23: 1293–1304. [Crossref], [Web of Science ®] , [Google Scholar] modified for particles (Seinfeld and Pandis 1998 Seinfeld, J. H. and Pandis, S. N. 1998. Atmospheric Chemistry and Physics, 958–996. New York, , USA: Wiley.  [Google Scholar]), in CMAQ, and with constant value used in RAINS-ASIA. Those expressions give different dynamics. Generally, the result for this study is between the result of modified Wesely's expression and CMAQ. When using the modified Wesely's expression with the number of sections being equal or smaller than 10, the resultant size distribution does not give the peak shape accurately.     

Reproducible unipolar resistive switching behaviors in the metal-deficient CoOx thin film

Pt/CoO_x/Pt tri-layers exhibited reproducible and stable unipolar switching under a dc sweeping voltage. In order to investigate the role of oxygen reduction in the metal-deficient CoO_x layer, resistive switching of the post-annealed CoO_x thin film was compared with those of the as-deposited CoO_x thin film. X-ray photoemission spectroscopy showed larger reproducible resistance switching and decreasing of current level in the post-annealed CoO_x thin film. This may be explained by a reduction in oxygen stoichiometry without phase transformation of the CoO_x. In addition, stable switching in post-annealed CoO_x layer is considered to originate from the decrease of the Co vacancies in local Co₃O₄ region partially distributed in the whole CoO_x layer, not in the dominant CoO.     

Realization of high mobility p-type co-doped ZnO: AlN film with a high density of nitrogen-radicals

High mobility p-type ZnO:AlN thin films have been efficiently realized by utilizing pre-activated nitrogen (N) plasma sources with an inductively coupled dual target co-sputtering system. High density of N-plasma-radicals was generated with an additional RF power applied through a ring-shaped quartz-tube located inside the chamber during co-sputtering process. The AlN codoped ZnO film shows excellent p-type behavior with a high mobility and a hole concentration of 154 cm^2°V^− 1s^− 1 and about 3 × 10^18°cm^− 3 at 600 °C, respectively. Electrical properties of p-n homo-junction devices based on p-type ZnO film are also discussed.     

Deformation analysis of rubber seal assembly considering uncertainties in mechanical properties

Journal of Mechanical Science and Technology - Rubber seals are used in the assemblies of mechanical parts in automobiles and aircrafts to prevent lubricant leakage and inclusion of foreign object....     

Effect of extended colostrum feeding on plasma glucagon-like peptide-1 concentration in newborn calves

Glucagon-like peptide-1 (GLP-1) plays a role in the regulation of glucose homeostasis via the stimulation of insulin secretion. The objective of this study was to evaluate the effect of extended colostrum feeding on plasma concentration of GLP-1. Holstein bull calves (n = 27) were fed pooled colostrum at 7.5% of birth body weight at 2 h after birth and then fed mature milk (M), a 50:50 mixture of pooled colostrum and milk (CM), or pooled colostrum (C; n = 9 for each treatment) at 5% of birth body weight at 12 h after birth and every 12 h thereafter until 72 h after birth. Blood samples were obtained before (1 and 2 h after birth) and after (until 72 h after birth; 42 time points) the first colostrum feeding, and plasma concentrations of glucose, insulin, and GLP-1 were measured. Data were analyzed by ANOVA of JMP 13 (SAS Institute Inc., Cary, NC) with treatment, time, and treatment × time interaction as fixed effects. Treatment × time interaction was observed for plasma insulin and glucose concentrations, which were mainly the result of lower concentrations from 1 to 2 d after birth for C compared with M. Conversely, on d 3 after birth, the difference between treatments was not observed for insulin and glucose. For the entire experimental period, plasma GLP-1 concentration was higher for C (2.25 ng/mL) compared with M (1.41 ng/mL) and tended to be higher compared with CM (1.58 ng/mL). A treatment × time interaction was observed for GLP-1, but unlike glucose and insulin, this was mainly the result of higher concentrations from 54 to 72 h after birth (on d 3 after birth) for C compared with M or CM. Postprandial plasma concentration of glucose was not correlated with that of GLP-1 but was positively correlated with that of insulin for the 4-h period after feeding on d 1 (r = 0.30) and d 3 after birth (r = 0.33). Postprandial plasma concentration of GLP-1 was positively correlated with that of insulin for the 4-h period after feeding on d 3 after birth (r = 0.20). These results indicate that extended colostrum feeding may increase plasma GLP-1 concentrations, especially 3 d after birth, but further study is necessary to determine the effect on plasma insulin and glucose concentrations.     

A 42‐GHz Wideband Cavity‐Backed Slot Antenna with Thick Ground Plane

We investigate the characteristics of a wideband and high‐gain cavity‐backed slot antenna in terms of the reflection coefficients, radiation patterns, and gain. A cavity‐backed slot antenna structure includes baffles, reflectors, and thick ground planes. The measured gain and bandwidth of a 10‐dB return loss in a cavity‐backed 2 × 2 array slot antenna with h₁=2 mm, d = 2 mm are 15.5 dBi and nearly 27% respectively, at 42 GHz. Baffles and reflectors are used to increase antenna gain, thus reducing the coupling among the slots on the thick ground plane.     

Finite element analyses of three dimensional fully plastic solutions using quasi-nonsteady algorithm and tetrahedral elements

To estimate entire elastic-plastic behaviors of cracked bodies, fully plastic solutions are utilized with linear elastic solutions in the engineering approach. Some numerical algorithms such as the Selective Reduced Integration/Penalty Function (SRI/PF) method have been developed and utlized to calculate various two-dimensional fully plastic solutions. However, only a few three-dimensional solutions have been obtained because of their numerical instability caused by the interaction among crack-tip singularity, material nonlinearity and incompressibility. This paper describes a new finite element algorithm for three-dimensional fully plastic solutions. The algorithm is basically classified into the mixed formulations. By introducing an artificial viscosity term to the governing equations, static crack problems are converted into quasi-nonsteady ones, which are solved using the fractional step method. The conversion makes the algorithm stable even in the analyses of complex crack geometries though it would need a number of iterations. In the analyses, mixed interpolation tetrahedral elements are also employed from a viewpoint of high quality mesh generation for three-dimensional cracked geometries. Numerical accuracy of the present algorithm is clearly demonstrated through the analyses of the three-dimensional fully plastic solutions of center cracked plates.     

Trend of visibility impairment caused by smog phenomenon in Seoul

The characteristics of visual air quality in Seoul have been investigated from March to November 1993. Optical properties, meteorological parameters, and particle characteristics were measured and analyzed. On the average, light scattering by particles is the dominant process in light extinction. Fine particle mass concentration, and the fraction of sulfate, nitrate and ammonium ions in the particles were found to play a major role in influencing the occurrence of a smog episode in Seoul. The role of ambient relative humidity on Seoul visibility is discussed.     

Facile Nondestructive Assembly of Tyrosine‐Rich Peptide Nanofibers as a Biological Glue for Multicomponent‐Based Nanoelectrode Applications

Achieving the nondestructive assembly of carbon nanoelectrodes with multiple components in a scalable manner enables effective electrical interfaces among nanomaterials. Here, a facile nondestructive multiscale assembly of multicomponent nanomaterials using self‐assembled tyrosine‐rich peptide nanofibers (TPFs) as a biological glue is reported. The versatile functionalities of the rationally devised tyrosine‐rich short peptide allow for (1) self‐assembly of the peptide into nanofibers using noncovalent interactions, followed by (2) immobilization of spatially distributed metal nanoparticles on the nanofiber surface, and (3) subsequent assembly with graphitic nanomaterials into a percolated network‐structure. This percolated network‐structure of silver nanoparticle (AgNP)‐decorated peptide nanofibers with imbedded single‐walled carbon nanotubes (SWNTs) proves to be a versatile nanoelectrode platform with excellent processability. The SWNT–TPF–AgNP assembly, when utilized as a flexible and transparent multicomponent electronic film, was quite effective for enhancing direct electron transfer (DET) as verified for a third‐generation glucose sensor composed of this film. The simple solution process used to produce the functional nanomaterials could provide a new platform for scalable manufacturing of novel nanoelectrode materials forming effective electrical contacts with molecules from diverse biological systems.     

Buckling Instability Control of 1D Nanowire Networks for a Large‐Area Stretchable and Transparent Electrode

A commonly used strategy to impose deformability on conductive materials is the prestrain method, in which conductive materials are placed on prestretched elastic substrates and relaxed to create wavy or wrinkled structures. However, 1D metallic nanowire (NW) networks typically result in out‐of‐plane buckling defects and NW fractures, due to their rigid and brittle nature and nonuniform load transfer to specific points of NW. To resolve these problems, an alternative method is proposed to control the elastic modulus of 1D NW networks through contact with various solvents during compressive strain. Through solvent contact, the interface interactions between the NWs and between the NW and substrate can be controlled, and it is shown that the surface instability of the 1D random network is formed differently from a uniform bilayer film, which also can vary with the modulus of the network. For modulus values lower than the critical point, slippage and rearrangement of NW strands mainly occur and individual strands in the network show an in‐plane wavy configuration, which is ideal for structural stretchability. Based on the solvent‐assisted prestrain method, letter‐sized, large‐area stretchable, and transparent electrodes with high transparency and conductivity are achieved, and stretchable and transparent alternating current electroluminescent devices for stretchable display applications are also realized.