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11.
K.M. Gangotri Om Prakash Regar Chhagan Lal Prashant Kalla Kishna Ram Genwa Rajni Meena 《国际能源研究杂志》1996,20(7):581-585
Photogalvanic effects were studied in a photogalvanic cell containing toluidine blue, glucose and tergitol-7 as a photosensitizer, reductant and surfactant, respectively. The photocurrent and photopotential generated by this system were 70 μA and 315 mV, respectively. The effects of different parameters on the electrical output of the cell were observed. Current/voltage characteristics of the cell have also been studied, and a mechanism has been proposed for the generation of photocurrent in photogalvanic cell. 相似文献
12.
Nepal, one of the least developed countries, is characterized by low per capita energy consumption and hugely dominated by traditional energy sources. Despite having enormous potential of hydro-electricity, only 50% of the total population has access to grid electricity. Firewood is the primary energy source for domestic purposes in rural environments. Due to geographical remoteness, a scattered consumer, higher costs of supply and maintenance, low consumption and low level of households’ income linking the rural areas to national electricity grid is difficult and implausible. In order to solve the energy problem in rural areas, Nepal’s government has initiated the production and distribution of several renewable energy technologies. Among several renewable technologies, micro-hydropower has been one of the most promising and widely adopted decentralized technologies to distribute electricity in rural areas. This article begins with a general overview of energy situation in Nepal. Present status and perspective of micro-hydro plants have also been discussed. Similarly, the dynamics of the relationship between electricity and socio-economic development has been analyzed by means of a typical rural electrification project in Tangting, Nepal by assessing the impacts of electricity on health, education, environment, and income in the village. The community has greatly benefitted from the arrival of environment friendly and affordable electricity. It has been concluded that the task of providing electricity to more remote and isolated villages is still challenging in Nepal. More systematic and comprehensive study supported by research and development is required to extend micro-hydro based electricity in more remote and poor communities of Nepal. 相似文献
13.
14.
Atmospheric deposition of polycyclic aromatic hydrocarbons to Atlantic Canada: geographic and temporal distributions and trends 1980-2001 总被引:1,自引:0,他引:1
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. The semivolatile organic compounds may disperse into the atmosphere by direct input from several sources such as the burning of fossil fuels, from motor vehicle emissions, and forest fires. Once in the atmosphere, they may travel great distances before being deposited to the earth's surface by the scavenging action of rain and snow. Up to 14 PAHs were determined in wet precipitation samples collected monthly from five sites in the four Canadian Atlantic Provinces during 1980-2001. The relatively more volatile PAHs (phenanthrene, fluoranthene, naphthalene, and pyrene) were predominant in the samples. Significant (P < 0.05) spatial variations in the deposition of some PAHs were observed among sites, but there were no consistent geographic patterns. Seasonal patterns were discernible with peak deposition for sigma6&14 PAHs occurring during the colder months of the year (December to March) and coinciding with higher energy consumption for heating and transport. The monthly volume weighed mean concentration for sigma6 PAHs has declined steadily since the mid-1980s at Kejimkujik National Park in southwest Nova Scotia, with a calculated half-life of 6.4 +/- 0.3 years. The maximum annual deposition flux of 20 microg m(-2) yr(-1) reached in 1985 for sigma6 PAHs decreased approximately 1 order of magnitude by the year 2000. The decrease in sigma6&14 PAHs for the region was found to be correlated (P < 0.05) with decreasing sulfate ion concentrations in the precipitation. The implementation of air pollution abatement programs in Canada, the United States, and elsewhere, switching to cleaner sources of energy and improved technology during the pastfew decades is most likely responsible for the observed decline. 相似文献
15.
A relatively simple and more economical process of open die hot pressing has been employed in preparing high density yttrium iron garnet samples of fine grain size (~ 1–2 μM). The samples have been investigated for the microstructure dependent spinwave line-width (ΔHk) and FMR line-width (ΔH). The values of ΔHk and ΔH are in fair agreement with the samples having the same grain size but prepared by the conventional hot pressing using refractory dies. 相似文献
16.
This article compares empirically the major factors affecting blinded and sighted reviewers in the selection of research proposals to be funded in a "scientifically small" country. Fisher's Z-test shows that the applicant characteristics (rank of undergraduate school where the applicant studied, professional age of the applicant, and academic recognition of the applicant) are the major factors leading to the significantly different evaluation scores between blinded and sighted reviewers. This means that "open" evaluation of research proposals is obviously biased. Policy implications of the findings and future research directions are discussed. 相似文献
17.
Various glasses in the system (65 – x)[SrO · TiO2]-(35)[2SiO2 · B22O3]-(x)La2O3, where x = 1,5,10 (wt%) were prepared by melting in alumina crucible (1375–1575 K). Heat treatment schedules were selected from DTA plots of respective glasses. X-ray diffraction studies of glass ceramic samples containing different concentrations of La2O3 revealed the formation of Sr2B2O5, Sr3Ti2O7 and TiO2 (rutile) phases. The addition of La2O3 results in the development of well formed, elongated crystallites of different phases. Results of the dielectric behaviour demonstrate higher values of dielectric constant for some of the glass ceramic samples. This can be ascribed to the relaxation polarization at the crystal-glass interface due to conductivity differences between crystalline and glassy phases. 相似文献
18.
Archana Pandey Abhishek Prasad Sindhu Singh Om Parkash Devendra Kumar 《Journal of Materials Science: Materials in Electronics》2008,19(11):1122-1127
Effect of manganese and cobalt doping (0.50 mole%) on electrical properties of ZnO based varistors has been studied using
complex plane modulus analysis. It is found that total resistivity of Mn doped sample is more as compared to that of Co doped
sample. This has been ascribed to existence of Mn in variable valence states viz. Mn2+, Mn3+ and Mn4+ which promotes hopping conduction leading to increase in the conductivity as compared to Co doped sample, in which Co exists
predominantly in +3 state with traces of Co2+ or Co+4 states. This accounts for its less conductivity. Mechanism of conduction is the same for grains and grainboundaries. 相似文献
19.
Ceria (La3+, Sr2+)/Carbonates Nanocomposite Electrolytes with High Electrical Conductivity for Low‐Temperature SOFCs 下载免费PDF全文
Nandini Jaiswal Devendra Kumar Om Parkash Shail Upadhyay 《International Journal of Applied Ceramic Technology》2015,12(5):1080-1087
A series of ceria‐based nanocomposites consisting of lanthanum and strontium codoped ceria with composition Ce0.89La0.07Sr0.04O1.925 (CL7S4) and eutectic mixture of carbonates Li2CO3‐Na2CO3 (LNCO) have been prepared by mixing nanosize powders of CL7S4 and LNCO. Samples have been characterized using differential thermal analysis, X‐ray diffraction, scanning electron microscopy combined with energy‐dispersive spectroscopy, thermal expansion, and impedance spectroscopy. A sharp increase in ionic conductivity is observed in all the composite specimens corresponding to superionic transition. Sample containing 35 wt% of carbonate shows the maximum conductivity (2.56 × 10?1 S/cm at 500°C) with activation energy of conduction, Ea 0.23 eV. 相似文献
20.
Sonal Singhal Amit Kumar Chawla Hari Om Gupta Ramesh Chandra 《Nanoscale research letters》2010,5(2):323-331
Zn0.9Cd0.1S nanoparticles doped with 0.005–0.24 M cobalt have been prepared by co-precipitation technique in ice bath at 280 K. For
the cobalt concentration >0.18 M, XRD pattern shows unidentified phases along with Zn0.9Cd0.1S sphalerite phase. For low cobalt concentration (≤0.05 M) particle size, d
XRD is ~3.5 nm, while for high cobalt concentration (>0.05 M) particle size decreases abruptly (~2 nm) as detected by XRD. However,
TEM analysis shows the similar particle size (~3.5 nm) irrespective of the cobalt concentration. Local strain in the alloyed
nanoparticles with cobalt concentration of 0.18 M increases ~46% in comparison to that of 0.05 M. Direct to indirect energy
band-gap transition is obtained when cobalt concentration goes beyond 0.05 M. A red shift in energy band gap is also observed
for both the cases. Nanoparticles with low cobalt concentrations were found to have paramagnetic nature with no antiferromagnetic
coupling. A negative Curie–Weiss temperature of −75 K with antiferromagnetic coupling was obtained for the high cobalt concentration. 相似文献