Effective polarization control of metallic planar chiral metamaterials with complementary rosette pattern fabricated by nanoimprint lithography

In this work the interaction between the metallic planar chiral metamaterials (PCM) with complementary rosette pattern and the incident electromagnetic wave was studied theoretically using finite difference time domain (FDTD) method. Both the evolution of the electric field distribution as the electromagnetic wave propagated through this PCM and the optic activity in near infrared range were investigated. By utilizing nanoimprint lithography technology, we successfully fabricated metallic PCM with complementary rosette pattern with period of 600 nm. The measurement results of polarization rotation capability indicate that by easily tuning the depth of the imprint depth in SU-8, the optical activity of this metallic PCM could be effectively controlled for specific wavelength.     

The price elasticity of the residential demand for electricity in the Vepco service area

In this study, we derive seasonal estimates of price elasticities of the residential demand of electricity in the Vepco service area from a detailed integrated economietic and end-use model that does not constrain the demand function to constant elasticities with respect to the explanatory variables. The elasticity coefficients derived from the model conform to expectations based on theoretical considerations.We also examine the structural stability of the demand function for residential electricity in the Vepco service area during 1969: 2–1980: 4. Two shifts are detected, one at the beginning of 1976 and the other at the end of 1978. The first shift is attributed to the delayed reaction of Vepco residential customers to the oil embargo and the subsequent increases in energy prices; the second relates to increased energy consciousness brought about by continued high prices of energy and also by encouragement from the federal government to conserve.     

Indoor air quality for poor families: new evidence from Bangladesh

Poor households in Bangladesh depend heavily on wood, dung and other biomass fuels for cooking. This paper provides a detailed analysis of the implications for indoor air pollution (IAP), drawing on new 24-h monitoring data for respirable airborne particulates (PM10). A stratified sample of 236 households was selected in Dhaka and Narayanganj, with a particular focus on fuel use, cooking locations, structural materials, ventilation practices, and other potential determinants of exposure to IAP. At each household, PM10 concentrations in the kitchen and living room were monitored for a 24-h period during December, 2003-February, 2004. Concentrations of 300 microg/m3 or greater are common in our sample, implying widespread exposure to a serious health hazard. A regression analysis for these 236 households was then conducted to explore the relationships between PM10 concentrations, fuel choices and a large set of variables that describe household cooking and ventilation practices, structure characteristics and building materials. As expected, our econometric results indicate that fuel choice significantly affects indoor pollution levels: natural gas and kerosene are significantly cleaner than biomass fuels. However, household-specific factors apparently matter more than fuel choice in determining PM10 concentrations. In some biomass-burning households, concentrations are scarcely higher than in households that use natural gas. Our results suggest that cross-household variation is strongly affected by structural arrangements: cooking locations, construction materials, and ventilation practices. A large variation in PM10 was also found during the 24-h cycle within households. For example, within the 'dirtiest' firewood-using household in our sample, readings over the 24-h cycle vary from 68 to 4864 microg/m3. Such variation occurs because houses can recycle air very quickly in Bangladesh. After the midday meal, when ventilation is common, air quality in many houses goes from very dirty to reasonably clean within an hour. Rapid change also occurs within households: diffusion of pollution from kitchens to living areas is nearly instantaneous in many cases, regardless of internal space configuration, and living-area concentrations are almost always in the same range as kitchen concentrations. By implication, exposure to dangerous indoor pollution levels is not confined to cooking areas. To assess the broader implications for poor Bangladeshi households, we extrapolate our regression results to representative 600 household samples from rural, peri-urban and urban areas in six regions: Rangpur in the north-west, Sylhet in the north-east, Rajshahi and Jessore in the west, Faridpur in the center, and Cox's Bazar in the south-east. Our results indicate great geographic variation, even for households in the same per capita income group. This variation reflects local differences in fuel use and, more significantly, construction practices that affect ventilation. For households with per capita income 相似文献   

Evaluation of the microbial contamination of fresh produces and their cultivation environments from farms in Korea

Food Science and Biotechnology - In this study, a total of 195 samples including fresh produce and farming environments was used to perform the microbial risk assessment. Levels of total aerobic...     

A new chemically amplified resist for high resolution patterning by E-beam lithography

In this work, we have undertaken evaluation of the lithography property of a recently available chemically amplified resist (CAR) resist, UV1116 supplied by Rohm and Haas Company. Systematic study of the EBL property such as sensitivity, contrast, high resolution limit and dense capability, as well as resistance to plasma dry etching has been carried out. In comparison with the performance of UVIII, we conclude that the UV1116 can be a good alternative with better lithography quality.     

Characterization of pyruvate decarboxylase genes from rice

The pdc1 gene encoding pyruvate decarboxylase has been isolated and sequenced from an IR54 rice genomic library. In contrast to a previously isolated intron-less rice genomic pdc, pRgpdc3, this gene contains five intervening introns in the coding region and corresponds to a cDNA clone, pRcpdc1, isolated from an IR54-cDNA library constructed from anaerobically-induced mRNAs. Comparison of the deduced amino acid sequence of this gene with that of the rice pdc2 and pdc3 showed 88% and 89% similarity, and 78% and 79% identity, respectively. Southern blots indicated that more than three genes constitute the pdc gene family in rice. pdc1 is highly inducible under anaerobic conditions. Rice pdc2 is also inducible by anoxia but to a much lesser extent than pdc1.