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Amorphous/crystalline silicon heterojunctions (a-Si:H/c-Si SHJ) were prepared by plasma-enhanced chemical vapor deposition (PECVD). The influence of the initial transient state of the plasma and the hydrogen pre-treatment on the i...
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Amorphous/crystalline silicon heterojunctions (a-Si:H/c-Si SHJ) were prepared by plasma-enhanced chemical vapor deposition (PECVD). The influence of the initial transient state of the plasma and the hydrogen pre-treatment on the interfacial properties of the heterojunctions was studied. Experimental results indicate that: (1) The instability of plasma in the initial stage will damage the surface of c-Si. Using a shutter to shield the substrate for 100 s from the starting discharge can prevent the influence of the instable plasma process on the Si surface and also the interface between a-Si and c-Si. (2) The effect of hydrogen pre-treatment on interfacial passivation is constrained by the extent of hydrogen plasma bombardment and the optimal time for hydrogen pre-treatment is about 60 s.
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For the HIT solar cells, the properties of interface between intrinsic thin film and c-Si are critical for the resulting device. The interfacial properties mainly depend on the surface passivation quality of c-Si, which is found t...
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For the HIT solar cells, the properties of interface between intrinsic thin film and c-Si are critical for the resulting device. The interfacial properties mainly depend on the surface passivation quality of c-Si, which is found to be affected by the morphology of textured surfaces. In this study, four kinds of textured c-Si substrates are fabricated: large pyramids without chemical polished (CP), large pyramids with CP, small pyramids without CP and small pyramids with CP. We investigated the effects of textured-surface morphology on the passivation of c-Si, the thin layer coverage and the interfacial properties of heterojunction prepared by HWCVD. Minority carrier lifetime measurements show that the wafer with small pyramids leads to better surface passivation than the one with large pyramids. The good coverage and contact between the thin film and the substrate can be achieved and no epitaxial growth occurs on the wafer with small pyramids through the study of TEM. Dark I-V measurements reveal that the heterojunction on wafer with small pyramids and CP has low recombination at the a-Si:H/c-Si interface. Our results indicate that the surface with small pyramids and low surface roughness is beneficial to the performance of HIT solar cells.
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The original blue-grained wheat, Blue 58, was a substitution line derived from hybridization between common wheat (Triticum aestivum L., 2n = 6x = 42, ABD) and tall wheatgrass (Thinopyrum ponticum Liu & Wang = Agropyron elonga...
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The original blue-grained wheat, Blue 58, was a substitution line derived from hybridization between common wheat (Triticum aestivum L., 2n = 6x = 42, ABD) and tall wheatgrass (Thinopyrum ponticum Liu & Wang = Agropyron elongatum, 2n = 10x = 70, StStE~eE~bE~x), in which one pair of 4D chromosomes was replaced by a pair of alien 4Ag chromosomes (unknown group 4 chromosome from A. ponticum). Blue aleurone might be a useful cytological marker in chromosome engineering and wheat breeding. Cytogenetic analysis showed that blue aleurone was controlled by chromosome 4Ag. GISH analysis proved that the 4Ag was a recombination chromosome; its centromeric and pericentromeric regions were from an E-genome chromosome, but the distal regions of its two arms werefrom an St-genome chromosome. On its short arm, there was a major pAs1 hybridization band, which was very close to the centromere. GISH and FISH analysis in a set of translocation lines with different seed colors revealed that the gene(s) controlling theblue pigment was located on the long arm of 4Ag. It was physically mapped to the 0.71-0.80 regions (distance measured from the centromere of 4Ag). The blue color is a consequence of dosage of this small chromosome region derived from the St genome. We speculate that the blue-grained gene(s) could activate the anthocyanin biosynthetic pathway of wheat.
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The effect of inorganic salts such as sodium chloride on the hydrolysis of chitosan in a microwave field was investigated.While it is known that microwave heating is a convenient way to obtain a wide range of products of different...
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The effect of inorganic salts such as sodium chloride on the hydrolysis of chitosan in a microwave field was investigated.While it is known that microwave heating is a convenient way to obtain a wide range of products of different molecular weights only by changing the reaction time and/or the radiation power,the addition of some inorganic salts was shown to effectively accelerate the degradation of chitosan under microwave irradiation.The molecular weight of the degraded chitosan obtained by microwave irradiation was considerably lower than that obtained by traditional heating.Moreover,the molecular weight of degraded chitosan obtained by microwave irradiation assisted under the conditions of added salt was considerably lower than that obtained by microwave irradiation without added salt.Furthermore,the effect of ionic strength of the added salts was not linked with the change of molecular weight.FTIR spectral analyses demonstrated that a significantly shorter time was required to obtain a satisfactory molecular weight by the microwave irradiation-assisted inorganic salt method than by microwave irradiation without inorganic salts and conventional technology.
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A liquid metal cooled nuclear reactor, liquid metal fast reactor is an advanced type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal has safety advantages and it allows a much higher power density than...
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A liquid metal cooled nuclear reactor, liquid metal fast reactor is an advanced type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal has safety advantages and it allows a much higher power density than traditional coolants. Disadvantages include difficulties associated with inspection and corrosion problems. For a clear understanding of those phenomena related to diffusion, a study of self-diffusion and mutual diffusion in liquid metals is of critical importance. The molecular dynamics (MD) computer simulation technique has been used to study the self-diffusion and mutual diffusion processes of liquid lead. The diffusion coefficients and activation energy of liquid lead self-diffusion are calculated and the values are consistent with those in experimental results. The mutual diffusion relationship between the activation energy for liquid lead and solid iron is similar to previous results.
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The Ag5 proteins are the most abundant and immunogenic proteins in the venom secretory ducts of stinging insects. An antigen 5-like protein (named tabRTS) composed of 221 amino acid residues was purified and characterized from the...
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The Ag5 proteins are the most abundant and immunogenic proteins in the venom secretory ducts of stinging insects. An antigen 5-like protein (named tabRTS) composed of 221 amino acid residues was purified and characterized from the salivary glands of the horsefly, Tabanus yao (Diptera, Tabanidae). Its cDNA was cloned from the cDNA library of the horsefly's salivary gland. TabRTS containing the SCP domain (Sc7 family of extracellular protein domain) was found in insect antigen 5 proteins. More interestingly, there is an Arg-Thr-Ser (RTS) disintegrin motif at the C-terminus of tabRTS. The RTS motif is positioned in a loop bracketed by cysteine residues as those found in RTS-disintegrins of Crotalidae and Viperidae snake venoms, which act as angiogenesis inhibitors. Endothelial Cell Tube formation assay in vitro and chicken chorioallantoic membrane (CAM) angiogenesis assay in vivo were performed as to investigate the effect of tabRTS on angiogenesis. It was found that tabRTS could significantly inhibit angiogenesis in vitro and in vivo. Anti-alpha(1)beta(1) monoclonal antibody could dose-dependently inhibit the anti-angiogenic activity of tabRTS. This result indicated that tabRTS possibly targets the alpha(1)beta(1) integrin to exert the anti-angiogenic activity as snake venom RTS-/KTS-disintegrins do. The current work revealed the first angiogenesis inhibitor protein containing RTS motif from invertebrates, a possible novel type of RTS-disintegrin.
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The family Iridoviridae consists of 5 genera of double-stranded DNA viruses, including the genus Megalocytivirus, which contains species that are important fish pathogens. In a previous study, we isolated the first rock bream irid...
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The family Iridoviridae consists of 5 genera of double-stranded DNA viruses, including the genus Megalocytivirus, which contains species that are important fish pathogens. In a previous study, we isolated the first rock bream iridovirus from China (RBIV-C1) and identified it as a member of the genus Megalocytivirus. In this report, we determined the complete genomic sequence of RBIV-C1 and examined its in vivo expression profiles. The genome of RBIV-C1 is 112333 bp in length, with a GC content of 55% and a coding density of 92%. RBIV-C1 contains 4584 simple sequence repeats, 89.8% of which are distributed among coding regions. A total of 119 potential open reading frames (ORFs) were identified in RBIV-C1, including the 26 core iridovirus genes; 41 ORFs encode proteins that are predicted to be associated with essential biological functions. RBIV-C1 exhibits the highest degree of sequence conservation and colinear arrangement of genes with orange-spotted grouper iridovirus (OSGIV) and rock bream iridovirus (RBIV). The pairwise nucleotide identities are 99.49% between RBIV-C1 and OSGIV and 98.69% between RBIV-C1 and RBIV. Compared to OSGIV, RBIV-C1 contains 11 insertions, 13 deletions, and 103 single nucleotide mutations. Whole-genome transcription analysis showed that following experimental infection of rock bream with RBIV-C1, all but 1 of the 119 ORFs were expressed at different time points and clustered into 3 hierarchical groups based on their expression patterns. These results provide new insights into the genetic nature and gene expression features of megalocytiviruses.
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A season-reliant empirical orthogonal function (S-EOF) analysis is applied to seasonal mean precipitation over East Asia for the period of 1979-2004. The first two dominant modes account for 44% of the total interannual variance, ...
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A season-reliant empirical orthogonal function (S-EOF) analysis is applied to seasonal mean precipitation over East Asia for the period of 1979-2004. The first two dominant modes account for 44% of the total interannual variance, corresponding to post-ENSO and ENSO turnabout years, respectively. The first mode indicates that in El Nino decaying summer, an anomalous anticyclone appears over the western North Pacific (WNP). This anticyclone is associated with strong positive precipitation anomalies from central China to southern Japan. In the following fall, enhanced convection appears over the WNP as a result of the underlying warm SST anomalies caused by the increase of the shortwave radiative flux in the preceding summer. A dry condition appears over southeastern China. The anomalous precipitation pattern persists throughout the subsequent winter and spring. The second mode shows that during the El Nino developing summer the anomalous heating over the equatorial central Pacific forces a cyclonic vorticity over the WNP. This strengthens the WNP monsoon. Meanwhile, an anomalous anticyclone develops in the northern Indian Ocean and moves eastward to the South China Sea and the WNP in the subsequent fall and winter. This leads to the increase of precipitation over southeastern China. The anticyclone and precipitation anomalies are maintained in the following spring through local air-sea interactions. The diagnosis of upper-level velocity potential and midlevel vertical motion fields reveals a season-dependent Indian Ocean forcing scenario. The Indian Ocean basinwide warming during the El Nino mature winter and the subsequent spring does not have a significant impact on anomalous circulation in the WNP, because convection over the tropical Indian Ocean is suppressed by the remote forcing from the equatorial central-eastern Pacific. The basinwide warming plays an active role in impacting the WNP anomalous anticyclone during the ENSO decaying summer through atmospheric Kelvin waves or Hadley circulation.
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A field experiment was carried out to research the changes and spatial distributions of soil nutrients in saline-sodic soil for different number of cultivated years under drip irrigation. The distributions of available potassium (...
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A field experiment was carried out to research the changes and spatial distributions of soil nutrients in saline-sodic soil for different number of cultivated years under drip irrigation. The distributions of available potassium (AK), available phosphorus (AP), nitrate nitrogen (NO3 (-)-N), ammonium nitrogen (NH4 (+)-N), as well as the amount of total nitrogen (TN), total phosphorus (TP) and organic carbon (OC) in the 0-40 cm soil layers in saline-sodic soils planted with Leymus chinensis for 1, 2, and 3 years were studied. The results showed that the distance from the emitter had an obvious effect on soil nutrients. Drip irrigation had substantial effects on levels of AK, AP, and NO3 (-)-N. The contents of AK, AP, and NO3 (-)-N were very high in the area near the emitter in the horizontal direction. In the vertical direction, levels of all of the available and total soil nutrients decreased with increased soil depth. Levels of AK, AP, NO3 (-)-N, NH4 (+)-N, TN, TP, and OC all increased with continued cultivation of crops on saline-sodic soil using drip irrigation. Compared to the nutrients found in soils from the natural L. chinensis grasslands, the contents of AK and TP were higher in the drip-irrigated soils, although the contents of AP, NO3 (-)-N, and NH4 (+)-N were broadly comparable. Given the rate of improvements in nutrient levels, we forecast that the nutrients in drip-irrigated saline-sodic soils should match those of the natural L. chinensis grasslands after 3-6 years of cultivation.
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In the present paper microwave radiation has been used to introduce N-sulfo and O-sulfo groups into chitosan with a high degree of substitution and low-molecular weight.The sulfation of chitosan was performed in microwave ovens.It...
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In the present paper microwave radiation has been used to introduce N-sulfo and O-sulfo groups into chitosan with a high degree of substitution and low-molecular weight.The sulfation of chitosan was performed in microwave ovens.It was found that microwave heating is a convenient way to obtain a wide range of products of different degrees of substitution and molecular weight only by changing reaction time or/and radiation power.Moreover,microwave radiation accelerated the degradation of sul-fated chitosan,and the molecular weight of sulfated chitosan was considerably lower than that obtained by traditional heating.There are no differences in the chemical structure of sulfated chitosan obtained by microwave and by conventional technology.FTIR and ~(13)C NMR spectral analyses demonstrated that a significantly shorter time is required to obtain a satisfactory degree of substitution and molecular weight by microwave radiation than by conventional technology.In this present paper,we also determined antioxidant activity of low-molecular-weight and high-sulfate-content chitosans(LCTS).The results showed LCTS could scavenge superoxide and hydroxyl radical.Its IC_(50)is 0.025 and 1.32mg/mL,respectively.It is a potential antioxidant in vitro.
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