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Knowledge of exchange flow and its variations is important, because it determines the distribution of salt, nutrient, pollutant, and suspended sediment in estuaries. Although exchange flow has been studied extensively, their variations over the spring–neap tidal cycle remain unclear. Many studies have indicated that the exchange flow is weaker during spring tides than neap tides, but others have reported that it might be stronger during spring tides. Therefore, we investigated the spring–neap variation of an exchange flow and its cause based on intensive observational data and an analytical model applied to the Sumjin River estuary (SRE), Korea. The observations revealed that exchange flow increased during the spring tide but decreased during the neap tide. The horizontal salinity gradient increased about seven times more during spring tide than during neap tide in the middle of the estuary. The analytical model implied that the exchange flow in the SRE is mainly driven by the horizontal salinity gradient. The large horizontal salinity gradient and tidal current amplitude ratio in the SRE between the spring and neap tides suggests that the horizontal pressure gradient driven by the salinity gradient overwhelms vertical mixing in driving exchange flow in the SRE.

Abstract Acid mine drainage (AMD) is the largest environmental problem facing the world mining and processing industry because it has low pH and can contain high concentrations of potential pollutants. Biomass ash (BA) can be considered as a potential material for AMD treatment. The main goal of this work was to investigate potential use of Biomass ash of CPK-LA and PK-LA types for AMD remediation. Four UK BAs from different fuels (i.e. straw, meat and bone meal, poultry litter), synthetic AMD, and raw AMDs (Belovo and Ursk) were used for the AMD treatment experiments. Batch experiments showed that in 1 h the biomass ash from straw combustion can effectively neutralise the synthetic AMD and the Belovo AMD with removal of potential pollutants at the liquid-to-solid ratio (L/S) of 100–250 and 10–50, respectively. The biomass ashes from straw and poultry litter combustion can effectively remove pollutants from the Ursk AMD at L/S 100 and adjust pH. The metal concentrations of those treated AMDs met receiving water quality standards. Potential pollutants precipitated as carbonate/hydroxide/sulphate, co-precipitated with Fe oxyhydroxides and Ca phosphates, and appeared as new phases such as Ca, Cu, Zn phosphates and Ca, Fe phosphates. This investigation is essential for development of appropriate, environmentally friendly and economically rational waste management. Graphic Abstract

We aimed to develop a consortium of starter culture of effective microorganisms to prepare doenjang, a traditional Korean fermented food. Different ratios of Bacillus subtilis TKSP 24 (B), Aspergillus oryzae complex (A), Rhizopus nigricans (also named as Rhizopus stolonifera) (R), and Mucor racemosus 15 (M15) were selected as meju starter cultures to produce doenjang with improved quality. Microbial strain combinations (B: A: R and B: M15: R) were mixed separately at three different ratios [1:1:1 (w/w), 1:0.5:1.5 (w/w), and 1:1.5:0.5 (w/w)] to prepare BAR-1, BAR-2, BAR-3, BM15R-1, BM15R-2, and BM15R-3 doenjang samples. Quantitative analyses included free amino acids, free sugar, volatile and non-volatile organic acids, cellular antioxidant activity along with the presence of biogenic amines and aflatoxins, and microbial counts. Total free amino acids responsible for the sweet taste of doenjang were highest in BAR-2 (322.50 mg/100 g) and BM15R-3 (320.07 mg/100 g). Total volatile organic acid was highest in BAR-1 compared to other preparations. All doenjang samples had biogenic amines, especially histamine, below the toxicity level (500 mg/kg). Also, the aflatoxin and hazardous microbial count in the tested doenjang samples were below the level of toxicity. The findings suggest that use of multiple microbial strains in combination with R. nigricans as a starter culture could be a novel and effective approach to improve the nutrition and safety of fermented soybean food products of doenjang.

BRAFV600E mutation is the most common somatic variant in papillary thyroid carcinoma (PTC) and is associated with aggressive prognostic factors. The conventional detection method for BRAF mutations is polymerase chain reaction followed by Sanger sequencing. Recently, an immunohistochemistry (IHC) method using a BRAFV600E-specific antibody (VE1) has been developed and widely adopted in the clinics; however, there is a lack of evidence regarding the comparability of the IHC and Sanger sequencing methods. Our institution began using the BRAFV600E IHC test in January 2013. We retrospectively analyzed 697 samples that were tested using both the IHC and sequencing methods, and evaluated their concordance. BRAF mutation was detected in 90.0% (627/697) of samples using IHC and 83.4% (581/697) of samples using direct sequencing. The diagnostic parameters of IHC compared with Sanger sequencing were as follows: 100% sensitivity (581/581), 60.3% specificity (70/116), 92.7% positive predictive value (581/627), and 100% negative predictive value (70/70). No false negative results were recorded using IHC. The overall concordance rate between the two methods was 93.4% (651/697). Discordant results were found in 46 samples (6.6%), 29 of which were from cases with small tumors (< 6 mm), 8 were from cases with low tumor cellularity, and 9 were specimens yielding low-quality DNA. IHC using the VE1 antibody is a reliable and highly sensitive method for detecting the BRAFV600E mutation in classic PTC.

In this paper we propose a new iterative algorithm for finding a common fixed point of an infinitely countable family of Bregman quasi-nonexpansive mappings in reflexive Banach spaces. We give some applications of our algorithm to solving equilibrium problems, convex feasibility problems, variational inequalities of monotone operators and finding zeros of maximal monotone operators.

Metaldehyde, an organic pesticide widely used in the UK, has been detected in drinking water in the UK with a low concentration (

A gender disparity exists with respect to the incidence of papillary thyroid cancer (PTC), suggesting that sex hormones such as estrogen play a role in PTC development and progression. In this study, we compared estrogen receptor gene expression patterns in PTCs to determine the clinical significance of estrogen gene expression in PTC. We analyzed ESR1 and ESR2 messenger RNA expression counts using data from The Cancer Genome Atlas (TCGA). To validate the results of TCGA analysis, we analyzed microarray data (GSE 54958) from the Gene Expression Omnibus. ESR1 gene expression and ESR ratio (ESR1/ESR2) were significantly higher in PTC tissues than in paired normal thyroid tissues (mean 659.427 vs. 264.045 for ESR1, 92.017 vs. 19.064 for ESR ratio). Among female patients, ESR1 expression and ESR ratio were negatively correlated with increased age. ESR1 expression and ESR ratio were higher in patients with classic PTC, lymphovascular invasion, BRAF V600E mutation, and radioiodine therapy. Classification analysis demonstrated that higher ESR1 expression and a higher ESR ratio faced a worse overall survival (hazard ratio 6.348 for ESR1, 4.031 for ESR ratio). Validation microarray analysis demonstrated that ESR1 expression and ESR ratio were higher in tumor tissues, classic PTC, and BRAF V600E. Higher ESR1 expression and a higher ESR ratio were associated with aggressive prognostic factors and worse overall survival in female PTC patients. Our results suggest that ESR1 and ESR ratio can be used as prognostic markers to predict female patient survival and have potential as a therapeutic target.

When solar radiation is utilized as a high-temperature heat source, performance simulation of solar concentration systems is important, especially for a central-receiver system that involves a large number of sun-tracking reflectors. To account for the intermittent nature of solar radiation, an annual performance based on 8760 hourly simulations is desirable. Therefore, this study focuses on a more realistic simulation of a central-receiver concentrator system with the Typical meteorological year (TMY) data that typify characteristic meteorological conditions at a specific location. Optical efficiency simulations of the Daegu central-receiver concentrator system were performed with a Monte Carlo ray-tracing method, and the Direct normal irradiance (DNI) in the TMY data set generated from the database of Korea Meteorological Administration (KMA) was evaluated. The TMY data in Daegu show that 80 % of the DNI values are smaller than 500 W/m2 and the annual insolation of 931 kWh/m2/year corresponds to approximately one third of that calculated from the clear-sky DNI model. Monthly optical efficiencies range from 67.8 % in October to 63.2 % in June in the base case. In contrast to the difference in solar insolation, the optical efficiencies based on the clear-sky model are slightly smaller than the efficiencies based on the TMY data, with deviations within approximately 1 %. The small difference implies that the clear-sky model can be substituted when simulation or optimization of the optical efficiency is of interest.

The aim of this study is to evaluate a newly invented instrument, activated sludge plant controller (ASP-Con), and to optimize treatment processes by reducing energy consumption and saving costs in pursuance of achieving sustainable energy and water cycles. Although three hundred billion dollars of investment were put into the energy independence project to save energy and cost when operating wastewater treatment plant in Korea, it failed because the investments were allocated only to improvements of digester facilities, designs, and capacities. To propose a feasible optimization strategy for the wastewater treatment plant with minimal wastes, the ASP-Con was introduced and experimented in four major wastewater treatment plants in the Republic of Korea. This study identifies the optimal operating points for blower based on the oxygen uptake rate and dissolved oxygen measurement, and supported by ammonium measurements to run the plant efficiently in real time.

In 2011, the first Korean central-receiver solar thermal power plant targeting the generation of 200 kWe was developed as a government research project. The project motivated us to develop an optical modeling program using the Monte Carlo ray-tracing method so that we are able to analyze performances of the solar concentration system in detailed and rigorous ways and to gain ideas to improve it. In the program, solar limb darkening without circumsolar radiation to model the sun shape was considered, and a clear-day insolation model to calculate Direct normal insolation (DNI) values was adopted. According to the breakdown of the optical efficiency, our program was developed to investigate the effects of six constituent efficiencies, i.e., cosine, shadowing, reflectivity, blocking, air transmission and spillage. On the other hand, a hierarchical screening algorithm to determine shadowing and blocking and a parallel computing technique were implemented for acceleration, which overcomes a major drawback of the Monte Carlo method and thereby enables to calculate annual performances. Comparisons with NREL’s SolTrace were made, and good agreements validated the development of our program. The hourly optical performances of the Korean solar thermal power plant on the summer and winter solstices and the autumnal equinox were simulated in terms of the solar flux and power distributions and the optical efficiencies. Basic parametric studies with the installation height and the tilt angle of the solar receiver were carried out based on annual performances. It is demonstrated that our program not only offers optical performance guidelines for operation confirms but also suggests improvement ideas that could enhance the efficiency and lead to a potential scale-up.

A challenging issue that arises in achieving a combined cycle with concentrated solar power technology is the development of a solar receiver for compressed air. A solar receiver transfers heat from concentrated solar radiation to compressed air so that the air temperature is sufficiently increased to drive an air turbine. Using a simple modular extension, we have developed three solar receivers for compressed air based on the concept of the tubular receiver. Conventional tubular receivers are generally applied in liquid fluids, such as water or molten salt. Cavities and extended surfaces were designed and incorporated into the developed tubular receivers to improve the heat transfer to air. The receivers were also subjected to performance evaluation tests, which were conducted in the solar furnace of the Korea Institute of Energy Research, with ambient air compressed at 5 bar and expressed in terms of outlet temperature and receiver efficiency. Test results indicated the thermal characteristics of the three solar receivers for their proper use and facilitated the comparison of their performances. The results also provided a guideline to construct and simulate a solar receiver system composed of a series of receiver modules. The problems identified in this study can help improve the solar receiver system.

Investigating the relationship between the breakdown voltage and the capacitance of GaInN light-emitting diodes (LEDs), we find that a lower capacitance due to weaker internal electric field in depletion region or wider depletion width at the pn junction results in lower reverse leakage current and thus larger breakdown voltage. The measured breakdown voltage and capacitance of LEDs show a strong correlation, opening a nondestructive and non-intrusive way to estimate the breakdown voltage of an LED based on the capacitance-voltage measurement.

In this paper, we establish the existence of a fixed point for generalized nonexpansive multivalued mappings in hyperbolic spaces and we prove some \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta $$\end{document}Δ-convergence and strong convergence theorems for the iterative scheme proposed by Chang et al. (Appl Math Comp 249:535–540, 2014) to approximate a fixed point for generalized nonexpansive multivalued mapping under suitable conditions. Our results are the extension and improvements of the recent well-known results announced in the current literature.

We present an extragradient-type algorithm for solving bilevel pseudomonone variational inequalities. The proposed algorithm uses simple projection sequences. Under mild conditions, the convergence of the iteration sequences generated by the algorithm is obtained.

Carbon black is classified as carcinogen group 2B by International Agency for Research on Cancer (IARC). But it uncertained the effects of ultrafine carbon black particles on oxidative damage or inflammation. So we were focused to evaluate the oxidative damage or inflammation with ultrafine carbon black particles at gene expression level by using mouse macrophage cell line, and the co-effects with solvent coating to it. It was evaluated the changes of gene expression with real time RT-PCR, and oxidative DNA damage with Fragment Length Analysis with Restriction Enzyme (FLARE) assay in mouse macrophage (RAW264.7) cell line. Two kinds of carbon black induced the gene expression of cytokines related to acute inflammation, and with 0.1% methylcyclohexane coating were regulated conversely each other. The oxidative DNA damage with smaller size carbon black was increased than bigger one (the range with 500–30 nm). The 0.1% methylcyclohexane increased the damage by binding with each carbon black (the dose range with 100 ng/mL-100 μg/mL). In this study, we got the conclusion that the genotoxicity of carbon blacks are elevated with its size get smaller and their surface area wider, and with methylcyclohexane coating. It could cause DNA damage by promoting oxidative stress and inflammatory responses.

Eight miso products sold in supermarket were purchased from Japan and analyzed for the determination of biogenic amines (BAs). Quantitative determination of BAs in miso products was carried out by means of HPLC with spectrophotometric UV-VIS detector. The amines were extracted in acid aqueous solution (HClO4) and then derivatized by dansyl chloride. The levels of pH in the tested miso samples were ranged from 4.8–5.5. The BAs (tryptamine, 2-phenyl ethylamine, putrescine, cadaverine, agmatine, tyramine, and spermidine) determined in 8 miso samples were found in their respective range of ND-0.13, ND-4.20, ND-1.29, ND-0.87, ND-0.90, ND-4.19, and ND-3.57 mg%. None of the miso samples contained histamine and spermine, the major BAs of food poisoning.

This study proposes a structural design method for an outer tie rod installed in a passenger car. The weight of the outer tie rod is optimized by using the aluminum alloy Al6082M, which is developed as a steel-substitute material, and applying structural optimization techniques. The high strength aluminum with improved mechanical properties was developed to reduce the weight of the outer tie rod. The newly developed aluminum alloy Al6082M is applied as the material of the outer tie rod. The static strength due to inertia force, durability and buckling performances are considered in the structural design of the outer tie rod. At the proto design stage of a new outer tie rod, it is cost-effective to utilize FE (finite element) analysis to predict each of these performances. In addition, the current trend in the structural design of automobile parts is to use optimization techniques to reduce the weights of the parts. First, for an arbitrary base design, the static strength, the life cycle and the buckling load are calculated to check whether the design satisfies its criteria. Then, the critical performance is selected so as to include its loading condition only in the optimization process. In this study, the metamodel based optimization process using kriging is adopted to obtain the minimum weight satisfying the critical design requirement. Then, the feasibility of the determined optimum shape is investigated against the other performances. Finally, the optimum design of outer tie rod is modified by considering forging efficiency. The performances of the final design are investigated through simulation and experiment.

The basic purpose of a tire is to enhance vehicle performances such as driving performance, rolling resistance, durability, ride comfort, noise, wear resistance, etc. by acting as a flexible cushion. To meet the demand for increased vehicle performances, the design method of a tire has advanced. This study proposes a structural design method for tire contour by considering both the tread contour and the sidewall contour, simultaneously. Existing studies of tire contour optimization have focused on the tread contour and the sidewall, separately. Durability, maneuverability and ride comfort are performances that are commonly investigated in tire contour design. Durability, maneuverability and ride comfort can be measured by the values of the strain energy density, tension and vertical stiffness, respectively. The optimization technique using a metamodel is introduced to maximize durability while satisfying the imposed constraints of tension and ride comfort. To achieve this, the responses defined in the optimization formulation are expressed mathematically in explicit form with respect to the design variables by using the kriging surrogate model, resulting in a simple optimization problem. Then, the simulated annealing algorithm is utilized to find the global optimum.

In this paper, we consider a differentiable multiobjective optimization problem with generalized cone constraints (for short, MOP). We investigate the relationship between weakly efficient solutions for (MOP) and for the multiobjective optimization problem with the modified objective function and cone constraints [for short, (MOP) ? (x)] and saddle points for the Lagrange function of (MOP) ? (x) involving cone invex functions under some suitable assumptions. We also prove the existence of weakly efficient solutions for (MOP) and saddle points for Lagrange function of (MOP) ? (x) by using the Karush-Kuhn-Tucker type optimality conditions under generalized convexity functions. As an application, we investigate a multiobjective fractional programming problem by using the modified objective function method.

We introduce and study a class of -generalized vector variational-like inequalities and a class of -generalized strong vector variational-like inequalities in the setting of Hausdorff topological vector spaces. An equivalence result concerned with two classes of -generalized vector variational-like inequalities is proved under suitable conditions. By using FKKM theorem, some new existence results of solutions for the -generalized vector variational-like inequalities and -generalized strong vector variational-like inequalities are obtained under some suitable conditions.

The Gongsuwon Thrust in the Taebaeksan Basin is one of the important regional structures for the Phanerozoic tectonic evolution of the Korean Peninsula. The late Early Jurassic Bansong Group (Daedong Supergroup) is structurally overlain by the early Paleozoic Joseon Supergroup along the thrust in the Yeongwol area. We present four lines of evidence indicating that the siliciclastics of the Bansong Group suffered a prelithified deformation within the fault zone of the Gongsuwon Thrust; (1) strainfree quartz clasts both in the hinge and limb areas of isoclinal folds of the sandstone layer, indicating granular flow, (2) intact gravels in the conglomerate with pressure shadows filled by sandstone or shale matrix, (3) injection of mud into sandy layers, and (4) lensoidal marble blocks (Joseon Supergroup) with plastically deformed calcite grains within siliciclastics of the Bansong Group. We suggest that the deposition of the Bansong Group and the thrusting were coeval during the middle Mesozoic Daebo tectonic event.

Loss of macroalgae habitats has been widespread on rocky marine coastlines of the eastern Korean peninsula, and efforts for restoration and creation of macroalgal beds have increasingly been made to mitigate these habitat losses. Deploying artificial reefs of concrete pyramids with kelps attached has been commonly used and applied in this study. As a part of an effort to evaluate structural and functional recovery of created and restored habitat, the macroalgal community and food web structure were studied about a year after the establishment of the artificial macroalgal bed, making comparisons with nearby natural counterparts and barren ground communities. Dominant species, total abundance, and community structure of macroalgal assemblage at the restored macroalgal bed recovered to the neighboring natural bed levels during the study period. The main primary producers (phytoplankton and macroalgae) were isotopically well separated. δ13C and δ15N values of consumers were very similar between restored and natural beds but varied greatly among functional feeding groups. The range of consumer δ13C was as wide as that of primary producers, indicating the trophic importance of both producers. There was a stepwise trophic enrichment in δ15N with increasing trophic level. A comparison of isotope signatures between primary producers and consumers showed that, while suspension feeders are highly dependent on pelagic sources, invertebrates of other feeding guilds and fishes mainly use macroalgae-derived organic matter as their ultimate nutritional sources in both macroalgal beds, emphasizing the high equivalency of trophic structure between both beds. Isotopic signatures of a few mollusks and sea urchins showed that they use different dietary items in macroalgal-barren grounds compared with macroalgal beds, probably reflecting their feeding plasticity according to the low macroalgal biomass. However, isotopic signatures of most of the consumers at the barren ground were consistent with those at the macroalgal beds, supporting the important trophic role of drifting algae. Our results revealed the recoveries of the macroalgal community and trophic structure at the restored habitat. Further studies on colonization of early settlers and the following succession progress are needed to better understand the process and recovery rate in the developing benthic community.

A systematic study is performed to optimize aluminum nitride (AlN) epilayers grown on (0001) sapphire by metal-organic vapor-phase epitaxy. Specifically, the impact of the AlN nucleation conditions on the crystalline quality and surface morphology of AlN epilayers is studied. Atomic force microscopy (AFM) and x-ray diffraction (XRD) results reveal that the nucleation layer plays a critical role in the growth of subsequent layers. The magnitude of the TMAl flow of AlN nucleation layer is found to have a strong effect on the crystalline quality and surface morphology of the high-temperature (HT) AlN epilayer. A simple Al adatom-diffusion-enhancement model is presented to explain the strong dependence of the crystalline quality and surface morphology on TMAl flow. Furthermore, ammonia flow, nucleation temperature, and growth time of the AlN nucleation layer are found to affect the surface morphology and the crystalline quality as well. A trade-off is found between surface morphology and crystalline quality; that is, we do not obtain the best surface morphology and the highest crystalline quality for the same growth parameters. For optimized AlN nucleation layers and HT AlN epilayers, a clear and continuously linear step-flow pattern with saw-tooth shaped terrace edges is found by AFM on AlN epilayers. Triple-axis x-ray rocking curves show a full-width at half-maximum (FWHM) of 11.5 arcsec and 14.5 arcsec for the (002) and (004) reflection, respectively. KOH etching reveals an etch-pit density (EPD) of 2 × 107 cm−2, as deduced from AFM measurements.

Optical thin-film materials with low refractive index for broadband elimination of Fresnel reflection

Three-dimensional (3D) nanostructured thin films have attracted great attention due to their novel physical, optical, and chemical properties, providing tremendous possibilities for future multifunctional systems and for exploring new physical phenomena. Among various techniques to fabricate 3D nanostructures, oblique angle deposition (OAD) is a very promising method for producing arrays of a variety of 3D nanostructures with excellent controllability, reproducibility, low cost, and compatibility with modern micro-electronic processes. This article presents a comprehensive overview of the principle of OAD, and unique structural and optical properties of OAD-fabricated thin films including excellent crystallinity, accurate tunability of refractive indices, and strong light scattering effect which can be utilized to remarkably enhance performances of various systems such as antireflection coatings, optical filters, photoelectrodes for solar-energy-harvesting cells, and sensing layers for various sensors.

The purpose of this paper is to introduce a new iteration by the combination of the viscosity approximation with Meir-Keeler contractions and proximal point algorithm for finding common zeros of a finite family of accretive operators in a Banach space with a uniformly Gâteaux differentiable norm. The results of this paper improve and extend corresponding well-known results by many others.

In this paper, we introduce and study a new system of generalized nonlinear co-complementarity problems with set-valued mappings and construct an iterative algorithm for approximating the solutions of the system of generalized co-complementarity problems. We prove the existence of the solutions for the system of generalized co-complementarity problems with set-valued mappings without compactness and the convergence of iterative sequences generated by the algorithm in Hilbert spaces. We also study a new perturbed iterative algorithm for approximating a system of generalized co-complementarity problems with single-valued mappings in Hilbert spaces.

The purpose of this paper is to study systems of vector equilibrium problems. We establish some existence theorems for systems of vector equilibrium problems by using (S)+-conditions and Kakutani---Fan---Glicksberg fixed point theorem

In this paper, we study an operator version of the modified Browder-Tikhonov regularization method for finding a common solution for a system of ill-posed operator equations involving m-accretive operators Ai, i =0 , ... , N, in a reflexive Banach space. The convergence rates of the regularized solutions are estimated not only in the infinite-dimensional space, but also in connection with its finite-dimensional approximations without the weakly sequential continuity of the dual mapping. MSC: 47H17; 47H20

We report a low-resistance ohmic contact on undoped ZnO using a promising contact scheme of Ti/Al. Specific-contact resistivity, as low as 9.0 × 10-7 Ωcm2, was obtained from the Ti (300 A)/Al (3,000 A) contact annealed at 300°C. It was found that TiO was produced, and the atomic ratio of Zn/O was dramatically increased after annealing at 300°C. This provides the evidence that a number of oxygen vacancies, acting as donors for electrons, were produced below the contact. This leads to the increase of electron concentration via the reduction of contact resistivity.

By using the new parametric resolvent operator technique associated with (A, η, m)-monotone operators, the purpose of this paper is to analyze and establish an existence theorem for a new class of generalized nonlinear parametric (A, η, m)-proximal operator system of equations with non-monotone multi-valued operators in Hilbert spaces. The results presented in this paper generalize the sensitivity analysis results of recent work on strongly monotone quasi-variational inclusions, nonlinear implicit quasi-variational inclusions, and nonlinear mixed quasi-variational inclusion systems in Hilbert spaces. MSC: 49J40; 47H05; 90C33

The purpose of this article is to study the weak- and strong-convergence theorems of solutions to split a feasibility problem for a family of nonspreading-type mapping in Hilbert spaces. The main result presented in this paper improves and extends some recent results of Censor et al., Byrne, Yang, Moudafi, Xu, Censor and Segal, Masad and Reich, and others. As an application, we solve the hierarchical variational inequality problem by using the main theorem. MSC:47J05, 47H09, 49J25.

We investigated the effects of surface treatments by aqua regia and (NH4)2Sx on the electrical and the microstructural changes of Pd contact on p-type GaN during annealing. The formation of a surface oxide was suppressed by the (NH4)2Sx treatment, and S-Ga and S-N bonds with binding energy of 162.1 eV and 163.6eV were formed, degrading the structural ordering of Pd. After 300°C annealing, the contact resistivity in the aqua regia-treated sample increased significantly. This could be attributed to the outdiffusion of N atoms leaving N vacancies below the contact, as confirmed by the increase of the Pd (111) plane spacing probably due to the dissolution of N atoms in Pd interstitial sites. Meanwhile, the contact resistivity in the (NH4)2Sx-treated sample was not degraded and no change was observed in the Pd (111) plane spacing. These results suggest that S-Ga and S-N bonds formed on (NH4)2Sx-treated GaN could act as a diffusion barrier for the outdiffusion of N atoms. The contact resistivity for the aqua regia-treated sample decreased again, probably due to the outdiffusion of Ga as well as N atoms at 500°C.

Effects of surface treatment on the change of band bending at the surface of p-type GaN were studied using synchrotron radiation photoemission spectroscopy, and the results were used to interpret the reduction of contact resistivity by the surface treatment. The contact resistivity on p-type GaN decreased from (5.1±1.2)×10−1 to (9.3±3.5)×10−5Ω cm2 by the surface treatment using aqua regia prior to Pt deposition. Surface band bending was reduced by 0.58 eV and 0.87 eV after the surface treatments by HCl and aqua regia solutions, respectively. The atomic ratio of Ga/N decreased as the photoelectron detection angle was decreased, indicating that the surface oxide was mainly composed of Ga and O, GaOx, formed during high-temperature annealing for the generation of holes, and Ga vacancies, VGa, were produced below the GaOx layer. Consequently, the aqua regia treatment plays a role in removing GaOx formed on p-type GaN, leading to the shift of the Fermi level toward the energy levels of VGa located near the valence band edge. This causes the decrease of barrier height for the transport of holes, resulting in the good ohmic contacts to p-type GaN.

Electrical properties of Ni/Au ohmic contacts on p-type GaN were interpreted with the change of microstructure observed under transmission electron microscopy. The contact resistivity was decreased from 1.3×10−2 to 6.1×10−4 Ωcm2 after annealing at 600°C. The reduction is due to the dissolution of Ga atoms into Au−Ni solid solution formed during annealing, via the generation of Ga vacancies. Thus, net concentration of holes increased below the contact, resulting in the reduction of contact resistivity. At 800°C, N atoms decomposed; reacted with Ni, and forming cubic Ni4N. Consequently, N vacancies, acting as donors in GaN, were generated below the contact, leading to the increase of contact resistivity to 3.8×10−2 Ωcm2.

Temperature and injection-current dependencies of radiant flux from blue and ultraviolet GaInN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) were investigated. Experimental results indicate that, compared to blue LEDs, the radiative efficiency of ultraviolet LEDs is relatively insensitive to injection current. It is expected that shallow potential minima caused by indium fluctuation in high-indium-containing GaInN quantum wells for blue LEDs result in a high radiative efficiency at low injection currents due to the localization of carriers; however, the radiative efficiency decreases rapidly with increasing injection current due to the delocalization of carriers.

The purpose of this paper is to introduce the concept of total asymptotically nonexpansive mappings and to prove some Δ-convergence theorems of the mixed type iteration process to approximating a common fixed point for two asymptotically nonexpansive mappings and two total asymptotically nonexpansive mappings in hyperbolic spaces. The results presented in the paper extend and improve some recent results announced in the current literature. MSC:47H09, 47H10.

The purpose of this paper is to establish some coupled coincidence point theorems for generalized nonlinear contraction mappings with the mixed g-monotone property in the framework of metric spaces endowed with partial order. The theorems presented in this paper are generalizations and improvements of the several well-known results in the literature.

This paper is concerned with the problem of existence of solutions to the initial value problemu′(t) = A(t,u(t)), u(a) = z in a probabilistic normed space, whereA : [a, b) × D → E is continuous,D is a closed subset of a probabilistic normed spaceE, andz ∃ D. With a dissipative type condition onA, we estabilish sufficient conditions for this initial value problem to have a solution.

Humic acids (HA) are known as the precursors of carcinogenic compounds formed by the disinfection of drinking water. While conventional treatments were found to be inefficient HA removal processes in drinking water, advanced oxidation processes have been proven to have a significant effect in the treatment of HA. The degradation of HA was investigated using nano-sized zinc oxide (ZnO)/laponite composite (NZLC). The reactions occurred in a UVC reactor by considering following variables: pH, initial HA concentration, catalyst loading, addition of hydrogen peroxide (H2O2), and catalyst reuse. Water samples containing HA were analysed by ultraviolet/visible spectrophotometer and high-performance size-exclusion chromatography. Initial HA concentrations were tested by the Langmuir–Hinshelwood model with k and K ads values, determined to be 0.126 mg/L.min and 0.0257 L/mg, respectively. The change in pH affected the HA degradation efficiency by the photocatalytic activity where it was higher under acidic conditions rather than alkaline ones. Optimal catalyst loading was proved to be a constrained factor in influencing the photocatalytic efficiency: the increase of catalyst concentration enhanced the HA decomposition efficiency up to an optimum value of 20 g/L, where there was no further degradation with excess loading. The addition of H2O2 was investigated through homogenous and heterogeneous photocatalysis, and, heterogeneous photocatalysis showed higher removal efficiency due to the combined effect of both catalysts and H2O2. Finally, NZLC was effective for reuse and exhibited an excellent stability after six times of usage.

The purpose of this paper is by using Maingé’s approach to study the existence and approximation problem of solutions for a class of hierarchical variational inclusion problems in the setting of Hilbert spaces. As applications, we solve the convex programming problems and quadratic minimization problems by using the main theorems. Our results extend and improve the corresponding recent results announced by many authors. MSC: 47J05, 47H09, 49J25.

In this paper, the problem of modified iterative approximation of common fixed points of asymptotically nonexpansive is investigated in the framework of Banach spaces. Weak convergence theorems are established.

In this paper, we introduce a new algorithm for finding a common element of the set of fixed points of N strict pseudocontractions and the set of solutions of equilibrium problems with a pseudomonotone and Lipschitz-type continuous bifunction. The scheme is motivated by the idea of extragradient methods and fixed point iteration methods. We show that the iterative sequences generated by this algorithm converge strongly to the above mentioned common element under some suitable conditions on algorithm parameters in a real Hilbert space. And also, we consider the variational inequality problems as an application. MSC: 46H09; 47H10; 47J25; 65K10

Metaldehyde is a selective molluscicide used in the agricultural and residential sector to control slugs and snails for a wide variety of crops. In recent years, some water companies have started monitoring drinking water supply catchments for presence of this compound, with positive and concern results. Conventional techniques are yet to achieve complete efficient and feasible removal of metaldehyde. The aim of this study was to measure the efficiency of nano-sized zinc oxide/laponite composites (NZnC) in the effective removal of metaldehyde (influent concentration of 500 μg dm−3) through the interaction of photocatalysis. Reaction time, pH of sample solution and NZnC mass were tested against each other using a rotatable central composite design method of experimentation. Statistical tests showed that linear effects of time, quadratic/linear effects of NZnC mass and the interaction of pH and NZnC mass proved to be the most significant variables for degrading metaldehyde. Optimal values of each variable for the highest removal efficiency were achieved, being pH equal to 10.4 and NZnC mass added equal to 28 g. The rate of reaction was then predicted by non-linear regression of four models. The best fit was provided by the modified first-order with residual kinetic model, with the apparent degradation coefficient k equal to 0.0363 min−1 and the lowest remaining metaldehyde concentration observed among all runs was 278.7 μg dm−3. NZnC has shown to be a prominent nanotechnology for metaldehyde removal.

By using the partial ordering method, a more general type of Ekeland's variational principle and Caristi's coincidence theorem for set-valued mappings in probabilistic metric spaces are given in this paper. In addition, we give also a directly simple proof of the equivalence between theses theorems in probabilistic metric spaces.

In this paper, the existence theorems of fixed points and common fixed points for two weakly increasing mappings satisfying a new condition in ordered metric spaces are proved. Our results extend, generalize and unify most of the fundamental metrical fixed point theorems in the literature. MSC:47H09, 47H10.

One of the top design priorities for semiconductor chemical sensors is developing simple, low-cost, sensitive and reliable sensors to be built in handheld devices. However, the need to implement heating elements in sensor devices, and the resulting high power consumption, remains a major obstacle for the realization of miniaturized and integrated chemoresistive thin film sensors based on metal oxides. Here we demonstrate structurally simple but extremely efficient all oxide chemoresistive sensors with ~90% transmittance at visible wavelengths. Highly effective self-activation in anisotropically self-assembled nanocolumnar tungsten oxide thin films on glass substrate with indium-tin oxide electrodes enables ultrahigh response to nitrogen dioxide and volatile organic compounds with detection limits down to parts per trillion levels and power consumption less than 0.2 microwatts. Beyond the sensing performance, high transparency at visible wavelengths creates opportunities for their use in transparent electronic circuitry and optoelectronic devices with avenues for further functional convergence., Korea (South). Ministry of Intelligence and Economy (Contract K0004114), Korea Institute of Science and Technology (Grant 2E22121), Korea (South). Ministry of Environment (Research Program)

We propose a new method for solving equilibrium problems on polyhedra, where the underlying function is continuous and satisfies a pseudomonone assumption which is called an interior proximal cutting hyperplane method. The method is based on the special interior proximal function which replaces the usual quadratic function. This leads to an interior proximal algorithm. The algorithm can be viewed as combining the cutting hyperplane method and the special interior proximal function. Finally some preliminary computational results are given. AMS Mathematics Subject Classification 2000: 65K10; 90 C25.

The purpose of this article is to establish some new approximation theorems of common fixed points for a countable family of total asymptotically quasi-nonexpansive mappings in Banach spaces which generalize and improve the corresponding theorems of Chidume et al. and others. 2000 AMS Subject Classification: 47J05; 47H09; 49J25.