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This paper describes the impacts of the M5.8(5.1) Gyeongju earthquakes on groundwater levels using data obtained from a unique coastal monitoring well. The monitoring strategy integrates conventional water level monitoring with periodic, continuous measurements of temperature and electrical conductivity (EC) within the water column of the well. Another important component of the monitoring system is a new instrument, the InterfacEGG, which is capable of dynamically tracking the freshwater‐saltwater interface. Although the system was set up to monitor seawater intrusion related to over‐pumping, as well as rainfall and tidal effects, it recorded impacts associated with a large earthquake and aftershocks approximately 241 km away. Seismic energies associated with the M5.8(5.1) Gyeongju earthquakes induced groundwater flows to the monitoring well through fractures and joints in the crystalline basement rocks. Temperature and EC logging data showed that the EC vertical profile declined from an average of approximately 5300 to 4800 μS/cm following the earthquakes. The temperature profile showed a trend toward lower temperatures as the depth increased, a feature not commonly observed in previous studies. Data from the InterfacEGG suggested that the rise in EC was not due to the saltwater intrusion, but from the tendency for brackish water entering the borehole to induce convective mixing at deeper depths as the seismic waves travel through the well‐aquifer system. The increase in groundwater levels was caused by pulse of colder, less brackish water flowing into the well because of the earthquake. This behavior reflects an enhancement in rock permeability by removing precipitates and colloidal particles from clogged fractures, which improve the hydraulic connection with a nearby unit with a higher hydraulic head. This study suggests there is value added with a more aggressive monitoring strategy., Article impact statement: This paper describes the impacts of the M5.8(5.1) earthquakes on groundwater using data obtained from a novel integrated monitoring system. The study illustrates the value added by using continuous well logging rather than single‐depth measurements of water level change. In addition, a new instrument, InterfacEGG, proved to be useful in monitoring the freshwater‐saltwater interface. This new and innovative approach provided convincing evidence of the impact of the main earthquake on the groundwater system. Although our application herein was specifically concerned with changes associated with an earthquake, it demonstrates the potential usefulness of such an integrated system for monitoring the dynamic behavior of coastal aquifers.

A set of three donor-acceptor conjugated (D-A) copolymers were designed and synthesized via Stille cross-coupling reactions with the aim of modulating the optical and electronic properties of a newly emerged naphtho[1,2-b:5,6-b′]dithiophene donor unit for polymer solar cell (PSCs) applications. The PTNDTT-BT, PTNDTT-BTz, and PTNDTT-DPP polymers incorporated naphtho[1,2-b:5,6-b′]dithiophene (NDT) as the donor and 2,2′-bithiazole (BTz), benzo[1,2,5]thiadiazole (BT), and pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP), as the acceptor units. A number of experimental techniques such as differential scanning calorimetry, thermogravimetry, UV–vis absorption spectroscopy, cyclic voltammetry, X-ray diffraction, and atomic force microscopy were used to determine the thermal, optical, electrochemical, and morphological properties of the copolymers. By introducing acceptors of varying electron withdrawing strengths, the optical band gaps of these copolymers were effectively tuned between 1.58 and 1.9 eV and their HOMO and LUMO energy levels were varied between −5.14 to −5.26 eV and −3.13 to −3.5 eV, respectively. The spin-coated polymer thin film exhibited p-channel field-effect transistor properties with hole mobilities of 2.73 × 10−3 to 7.9 × 10−5 cm2 V−1 s−1. Initial bulk-heterojunction PSCs fabricated using the copolymers as electron donor materials and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as the acceptor resulted in power conversion efficiencies in the range of 0.67–1.67%. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2948–2958

Two new quinoxaline-based polymers, poly[1,5-didecyloxynaphthalene-alt-5,5′-(5,8-dithiophen-2-yl)-2,3-bis(4-octyloxyphenyl)quinoxaline (PNQx-p) and poly[1,5-didecyloxynaphthalene-alt-5,5′-(5,8-dithiophen-2-yl)-2,3-bis(3-octyloxyphenyl)quinoxaline (PNQx-m), were synthesized by Suzuki coupling reaction and characterized. Thermogravimetric analysis revealed that these polymers are thermally stable with degradation temperature up to 320 °C. As evident from the electrochemical and optical studies, the copolymers have comparable optical band gap (∼2 eV) and nearly similar deep highest occupied molecular orbital (HOMO) energy levels of −5.59 (PNQx-p) and −5.61 eV (PNQx-p). The resulting copolymers possessed relatively low HOMO energy levels promising good air stability and high open circuit voltage (Voc) for photovoltaic applications. The optimized photovoltaic device with a structure of ITO/PEDOT:PSS/PNQx-m:PC71BM (1:2, w/w)/LiF/Al shows a power conversion efficiency up to 2.29% with a short circuit current density of 5.61 mA/cm2, an Voc of 0.93 V and a fill factor of 43.73% under an illumination of AM 1.5, 100 mW/cm2. The efficiency of the PNQx-m polymer improved from 2.29 to 2.95% using 1,8-diiodoocane as an additive (0.25%). © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Newly proposed polymer electrolyte membranes (PEMs) composed of an electrospun poly(vinylidene fluoride) (PVDF) fibrous mat embedded in a poly(4-vinylpyridine) (P4VP) matrix were successfully fabricated in order to improve the mechanical and dimensional stabilities and ionic conductivity of membranes in lithium rechargeable batteries. Fourier transform infrared spectroscopic analysis showed that as a result of the use of a high voltage during electrospinning the crystalline structure of PVDF changed partially from α-phase to β-phase. Energy-dispersive X-ray spectroscopy confirmed the existence of crosslinked P4VP in the PVDF fibrous mat. The electrolyte uptakes of PVDF and PVDF/P4VP composite mats were higher than that of PVDF cast film. The tensile properties of PVDF/P4VP composite mat were considerably improved compared to those of the pristine PVDF fibrous mat under both dry and wet (soaked with electrolyte) conditions. In addition, the mechanical and dimensional stabilities of the PVDF/P4VP composite PEM were further enhanced due to crosslinking between the P4VP chains. Furthermore, the PVDF/P4VP composite PEM exhibited an ionic conductivity that was an order of magnitude higher than that of traditional PVDF film. © 2012 Society of Chemical Industry

Groundwater responses at 15 monitoring wells on Jeju Island were observed in relation to the magnitude 9.0 Tohoku Earthquake off the Pacific coast of Honshu, Japan, on 11 March 2011, at 14:46:23 h local time (05:46:24 h UTC time). In coastal areas, the groundwater level responses to the earthquake were oscillatory at 12 wells, and the range of the maximum groundwater level changes was 3–192.4 cm. The response durations were approximately 1–62 min. The relationship between the maximum groundwater level changes and the response durations displayed a high correlation coefficient (r = 0.81). Groundwater temperature changes were also observed at 7 of 12 wells 3–10 min after the seismic wave arrived, and the range was from 0.01 °C to 1.20 °C. In mid-elevation areas, the groundwater level changes appeared in three different forms: oscillatory, spiky and persistent. The groundwater temperature changes were also observed at two wells. One indicated decreasing and recovering temperatures, and the other exhibited rising and persistent temperatures. The primary temperature changes occurred 5–6 min after the earthquake and 2–3 min after the seismic wave arrived. In addition, the electrical conductivities at the depth of the transition zone were monitored, and the responses to the earthquake appeared at all three wells. Although the electrical conductivity and temperature changes were not well understood, groundwater inflow and mixing were likely caused by the earthquake, and the responses were various and site specific. The responses to the earthquake were closely related to the hydrogeological characteristics at each monitoring well, and a more detailed hydrogeological characterization is needed to understand the mechanisms related to earthquakes in general. Copyright © 2012 John Wiley & Sons, Ltd.

Three new polymers poly(3,4′′′-didodecyl) hexaselenophene) (P6S), poly(5,5′-bis(4,4′-didodecyl-2,2′-biselenophene-5-yl)-2,2′-biselenophene) (HHP6S), and poly(5,5′-bis(3′,4-didodecyl-2,2′-biselenophene-5-yl)-2,2′-biselenophene) (TTP6S) that have the same selenophene-based polymer backbone but different side chain patterns were designed and synthesized. The weight-averaged molecular weights (Mw) of P6S, HHP6S, and TTP6S were found to be 19,100, 24,100, and 19,700 with polydispersity indices of 2.77, 1.48, and 1.41, respectively. The UV–visible absorption maxima of P6S, HHP6S, and TTP6S are at 524, 489, and 513 nm, respectively, in solution and at 569, 517, and 606 nm, respectively, in the film state. The polymers P6S, HHP6S, and TTP6S exhibit low band gaps of 1.74, 1.95, and 1.58 eV, respectively. The field-effect mobilities of P6S, HHP6S, and TTP6S were measured to be 1.3 × 10−4, 3.9 × 10−6, and 3.2 × 10−4 cm2 V−1 s−1, respectively. A photovoltaic device with a TTP6S/[6,6]-phenyl C71-butyric acid methyl ester (1:3, w/w) blend film active layer was found to exhibit an open circuit voltage (VOC) of 0.71 V, a short circuit current (JSC) of 5.72 mA cm−2, a fill factor of 0.41, and a power conversion efficiency (PCE) of 1.67% under AM 1.5 G (100 mW cm−2) illumination. TTP6S has the most planar backbone of the tested polymers, which results in strong π–π interchain interactions and strong aggregation, leading to broad absorption, high mobility, a low band gap, and the highest PCE. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

A new method to tune both phosphorescence emission intensity and spectroscopic colors based on the alternatively structured host/guest multilayer thin films prepared by the spin-assisted LbL deposition is presented. Their emission characteristics are demonstrated with pairs of positively charged Ir-PEI complexes as guests and negatively charged CBZ-PAA as hosts. The phosphorescent emission of Ir-PEI complexes is enhanced by the energy transfer from the host to the guest and, additionally, this energy transfer can be finely tuned by the insertion of spacer layers between the phosphorescent donor and acceptor layers to vary the emission intensity as well as to render different emission colors.

Blue host materials for organic light-emitting diodes (OLEDs) based on silicon-cored (tetraphenylsilane) anthracene derivatives are synthesized. These compounds, with a non-coplanar molecular structure, have high glass-transition temperatures and good amorphous-film-forming capabilities. When doped with a blue-fluorescent dopant, blue emission with high color purity and high efficiency, up to 7.5 cd A(-1) and 6.3%, is achieved.

Zincphthalocyanine (ZnPc) thin films were prepared by the vacuum evaporation method under a pressure of 10-6 mbar. The X-ray diffraction analysis of vacuum evaporated ZnPc films reveals that the structure of the films is polycrystalline in nature. The photoconduction properties have been studied in the wavelength range 400 –800nm using suitable masks. The Photoconductivity of the films as a function of light intensity and applied voltage were studied and results were discussed in detail. The photoconduction was found to increase with higher light illumination and maximum at the band edge of the ZnPc thin film. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The colloidal properties of emulsans formed by incubations of Acinetobacter calcoaceticus RAG-1 on different carbon sources were studied. The apparent critical micelle concentrations (CMC) of the emulsans tested ranged from 25 to 58 mg/dm -1 . Surface and interfacial tensions of the solutions showed little dependence on pH between 2 and 10. In contrast, increasing the pH from 2 to 6.5 resulted in a substantial increase in their ability to effectively emulsify aliphatic hydrocarbons. Hexadecane-in water emulsions were prepared having droplet sizes between 6 and 19 μm. Many of the emulsions thus formed were found to be stable with respect to coalescence for several months. Certain structural features such as the total content of fatty acids and hydroxy fatty acids were found to have a significant effect on emulsifying activity. The maximum emulsifying activity occurred for emulsans containing about 460 nmol of total fatty acid per mg of emulsan (nmol mg -1 ). Emulsifying activity also showed a maximum at about 170 nmol mg -1 -emulsan of 2- and 3- hydroxy dodecanoic acids. For substituents having chain lengths ≥15 carbonatoms, the emulsifying activity on hexadecane increased with their content up to 190 nmol mg -1 . On the other hand, for substituents having chain lengths of

Curing behaviour of unsaturated polyester (UPE) resins based on recycled poly(ethylene terephthalate) (RPET) was investigated by measuring exotherms during cure employing differential scanning calorimetry. The UPE resins were prepared by glycolysis of RPET and polycondensation of the glycolysis product with maleic anhydride. In the preparation of the UPE resins, RPET content and glycol type were varied. The curing behaviour of the UPE resins based on RPET was similar to that of conventional UPE resins. The rate of cure increased with increasing RPET content of the UPE resin based on propylene glycol (PG) and RPET. It decreased with increasing RPET content of the UPE resin based on dipropylene glycol (DPG) and RPET. The final degree of isothermal cure increased with increasing RPET content, or changing the glycol type from PG to DPG, in the UPE resins. The curing behaviour was interpreted from the viewpoints of change in double bond concentration, inherent reactivity, and styrene/fumarate ratio of the UPE resins. ©1997 SCI

Organic solar cells based on compound (IIIb) exhibit promising photovoltaic device performance with a maximum power conversion efficiency up to 2.20% under the illumination of AM 1.5G, 100 mW cm-2.

Mg-doped GaN micro-crystals were prepared by the direct reaction of metal gallium and ammonia using magnesium chloride (MgCl 2 ) as Mg doping source. The growth of microcrystalline hexagonal GaN was clearly found from scanning electron microscopy and TEM measurements. The grain size of Mg-doped GaN crystals was larger than that of undoped GaN. Room temperature PL and CL spectra for Mg-doped GaN micro-crystal showed the blue emission at 2.75 and 2.85 eV, respectively.

However all of these procedures suffer from one or more of the following drawbacks such as long reaction time, low yield of the products, harsh reaction conditions, use of excess amount of reagents, tedious work up procedures and co-occurrence of several side reactions. In addition, most of the catalysts and reagents are expensive