188 resultados para 90-24-PC1

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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“果蔬贮藏保鲜技术”项目分四个获奖组成部分:1、荔枝贮藏保鲜技术研究——研制出荔枝果实零上低温贮藏保鲜30-40天,好果率90%以上,货架期24小时和室温贮藏保鲜7-10天的新技术等;2、赤霉酸控制椪柑、蕉柑生理枯水的技术——采用采前用赤霉酸喷果或采后混和防腐剂加生长素浸果、晾干、薄膜单果包装技术,达到抑制枯水的效果;3、控制红桔枯水的研究——应用赤霉酸加防腐保险剂和生产素处理,结合薄膜包装和适时采收,获得控制红桔枯水保鲜的良好效果;4、伊迈唑对防治柑桔青、绿霉病的效果试验——伊迈唑有较好的抑制柑桔青、绿霉菌的能力,对抗性绿霉孢子有较好的抑菌力。

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本文应用植物引种驯化,栽培学及植物化学的理论方法对引入我国的迷迭香(Rosmarinus officinalisL.)精油和抗氧化剂进行了研究.主要结果如下; 1、昆明地区的生态气候条件最适宜迷迭香生长。南京地区局部良好环境也能满足迷迭香正常生长需要。北京地区在保护栽培的情况下,迷迭香才能够安全越冬。 2、用GC-MS和GC-IR鉴定了迷迭香精油的23种成分。不同采收期精油成分含量变化有3种类型,即似单峰曲线,似8曲线和w曲线。一年生与二年生苗在精油成分含量上略有差异。与主要栽培国相比,我国不同引种地精油成分化学类型各具特点,北京地区α—蒎稀(31.58%)含量很高,南京地区富含樟脑(14.86%)乙酸龙脑酯(7.97%)和龙脑(6.90%)含量也相对较高,昆明地区则是α—蒎稀(24.32%)和1.8—桉叶油素(24.43%)含量并重。 乙酸龙脑酯含量的高低对精油香气质量优劣起关键作用。北京地区雨季来临收获(7月初)精油香气质量最好。南京地区,11月初精油香气质量也属优质。本实验未能得到高质量的昆明地区精油。 3、从迷迭香蒸油残渣中分离得到三种抗氧化成分,迷迭香酚( Rosrmanol)、鼠尾草酚(Carnosol)和迷迭香双醛(R0smadial),并用质谱,核磁做了鉴定.硫氰铁酸法、TBA法、AOM法检测了三种成分的抗氧化效能.Rosmanol对多双键不饱和脂肪酸抗氧化效果显著,Carnosol和BHT在不同双键脂肪酸中抗氧化效果稳定,Rosmadial的抗氧化效果则随不饱和双键数目的增加而降低。在猪油中,抗氧化效能的强度顺序为Rosmanol >carnosol>BR>Rosmadial。 抗氧化物质在植株体内是不断积累的。不同引种地迷选香抗氧化效能的强弱差异表现为昆明>北京>南京。 迷迭香的正己烷,两酮提取物抗氧化效能都是随着添加量的增加而增强、丙酮提取物的抗氧化效能优于正己烷提取物。 对迷迭香抗氧化剂提取工艺做了探讨,得到R-1,R—2,R-3三种小试样品,R-2,R-3的抗氧化效果优于BHT.B—l接近于BET。

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采用PEG/DMSO融合法,从普通烟草(Nicotiana tabacum L.cv.Xanthi nc)叶肉和毛曼陀罗(Datura innoxia Mill.)茎或叶愈伤组织原生质体融合获得I5株花盆中健康生长的族间体细胞杂种植株;其中11株是在没有选择压力的条件下获得,4株则是在有IOA和R6G选择系统存在下获得。同时获得一株试管开花且形态异常的植株和一株花盆中生长的嵌合植株。lOmM IOA和I5μ g/ml R6G均能分别有效地抑制烟草叶肉和毛曼陀罗愈伤组织原生质体的分裂;10% DMSO能显著提高原生质体融合率;PEG种类并不重要,但浓度则很重要;BAP较ZT,KT对植株分化有更好的诱导效果。杂种的形态、细胞、同工酶、Southern杂交,花粉育性分析结果如下:1、l5株杂种较双亲普遍株型矮小,生长缓慢,形态接近烟草但不很正常,根据形态特征可分为两种类型:(1)共有8株,其叶片大小、形状、颜色、开花习惯、花类型(单花)等均与毛曼陀罗接近,但子房败育;(2)共有7株,其株型、叶片形状、颜色、光滑度、花形状、类型(圆锥状花序)、颜色更接近烟草,但少数杂种开单花或先单花后圆锥状花序或先单花后两种花并存,且开花时间不一,部分子房败育。2、杂种染色体数目大都在60~90之间,个别者较少(48条)或较多(125条),没有一株为双二倍体(2n=96),并全部为混倍体。3、15株杂种植株均有双亲的细胞色素氧化酶同工酶特征谱带;大部分都有双亲的过氧化物酶同工酶特征谱带,少都仅具烟草的谱带。4、Hae Ⅲ/水稻rDNA的Southern杂交分析表明杂种1较双亲多一条谱带,杂种2较双亲也多一条弱带,其它杂种尚待定。5、花粉活力测定表明毛曼陀罗(种子再生而来)的为99%,烟草(原生质体再生而来)为80~90%,而杂种的为24~61%,育性普遍低于双亲。

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Linearly polarized light at normal incidence injects a spin current into a strip of two-dimensional electron gas with Rashba spin-orbit coupling. The authors report observation of an electric current when such light is shed on the vincinity of the junction in a crossbar-shaped InGaAs/InAlAs quantum well Rashba system. The polarization dependence of this electric current was experimentally observed to be the same as that of the spin current. The authors attribute the observed electric current to the scattering of the optically injected spin current at the crossing. (c) 2007 American Institute of Physics.

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全球气候变化已经成为不争的事实,其中全球变暖是近年来国内外的研究热点之一。土壤碳库作为陆地生态系统最大的碳库,气温升高必然会导致一系列的土壤碳储量和碳通量的变化,这些微小的变化又可能导致大气CO2浓度的变化并强化这种变暖的趋势。目前,土壤碳循环对温度升高的响应仍然是陆地碳循环研究最缺乏的部分,对土壤有机碳动态变化的研究仍存在着很大的不确定性与争议。四川西部的亚高山人工针叶林是青藏高原东部高寒林区的重要组成部分,是研究全球变化对森林生态系统影响的关键地区和重要森林类型。本研究通过采用原位人工模拟增温装置(Open-top chambers,OTCs)对川西米亚罗60年人工云杉林土壤实施增温,研究高海拔地区森林,尤其是人工森林系统下的土壤有机碳 含量、土壤呼吸及土壤酶活性对温度升高的响应。结果表明: 1. 增温处理的660天(2005年11月至2007年9月)期间,增温条件下的平均气温和土壤平均温度分别比对照提高0.43 ℃和0.27 ℃;0~10 cm土壤含水量在增温的不同时期均有不同程度的降低。 2. 土壤蔗糖酶、蛋白酶和脲酶活性在温度升高的不同阶段均有不同程度的提高。在增温处理300天(2006.09)、540天(2007.05)、600天(2007.07)和660天(2007.05)后,0~10 cm层的蔗糖酶活性分别比对照提高了36.36%(P<0.05)、24.31%、14.54%(P<0.05)和7.22%,脲酶活性分别提高了12.90%、24.19%(P<0.01)、34.48%(P<0.05)和14.64%(P<0.05),蛋白酶活性分别提高了31.37%、1.99%、3.70%和17.80%。10~20 cm层的土壤酶活性也均有不同程度的提高,但均没有显著差异。蔗糖酶、脲酶和蛋白酶活性均呈现出随土层加深而减弱的趋势。 3. 土壤过氧化氢酶和多酚氧化酶活性在增温的第1年内均有不同程度的提高,但在增温的第2年内比对照有所降低。增温300天后(2006.09),过氧化氢酶和多酚氧化酶在0~10 cm层分别比对照增加3.76%和49.25%(P<0.05),10~20 cm层分别增加了5.54%和29.67%。在增温的第2年内,增温540天(2007.05)、600天(2007.07)和660天(2007.09)后,0~10 cm层的过氧化氢酶活性分别比对照降低了27.70%(P<0.05)、4.34%和1.47%,多酚氧化酶活性分别降低了5.86%、11.76%(P<0.05)和7.47%。增温的第2年内,10~20 cm层的过氧化氢酶和多酚氧化酶活性也均有不同程度的降低,但差异均未达到显著水平。不同土层之间相比较,过氧化氢酶活性随土层加深而降低,多酚氧化酶活性随土层加深而增加。 4. 土壤有机碳和有机质在增温的不同阶段,含量比对照均有所降低;且随增温时间的延长,降低的幅度下降。0~10 cm层的土壤有机碳和土壤有机质在增温300天(2006.09)、540天(2007.05)、600天(2007.07)和660天(2007.09)后分别降低了8.69%、4.35%、3.80%和2.44%,差异均未达到显著水平。土壤全氮含量在增温后与对照相比无明显的增加或者降低趋势。增温条件下的土壤C/N比与对照相比有所降低,但在增温各阶段的差异均不显著。10~20 cm层的有机碳、有机质和C/N比也有不同程度的降低趋势,但差异均不显著。不同土层之间相比,0~10 cm层的有机碳、有机质、全氮含量和C/N比均高于10~20 cm层,呈现出随土层加深而降低的趋势。 5. 土壤呼吸速率在增温第1年内,与对照相比明显提高,但在增温处理2年后,与对照相比无显著变化。增温300天(2006.09)和360天(2006.11)后分别提高了13.32%和21.17%,差异显著。增温处理540天(2007.05)到660天(2007.09)期间,与对照相比,不仅没有明显的提升,反而有些月份比对照有所降低,对温度升高的敏感性降低,呈现出对温度升高的适应性。土壤呼吸的日呼吸速率呈现单峰曲线形式,在14:00~20:00期间达到最大值,在4:00~10:00期间具有最低值。土壤呼吸的季节变化,呈现出与外界环境温度相一致的趋势,在7月份(夏季) 最高,11月份(冬季)最低。土壤呼吸与2 cm土壤温度、5 cm土壤温度和空气温度均呈极显著指数相关,与0~10 cm土壤含水量呈线性相关,相关性达到显著水平,但低于土壤呼吸与温度的相关性。 The past century has seen a marked increase in atmospheric carbon dioxide concentrations and a concomitant warming that has drawn scientific attention to the link between global carbon stocks and climate change. In particular, the decomposition and turnover of soil organic matter is recognised as an important determinant of carbon driven climate change. The slightly variation in soil organic carbon will result in the increase of atmospheric carbon dioxide concentrations and reinforce the tendency of warming. The experiment was conducted in Subalpine coniferous forest in western Sichuan province. Subalpine coniferous forest in western Sichuan was a important part of eastern Qinghai-Tibetan Plateau, which play a important role in reseaching the sensitivity of forest ecosystem to climate change. To investigate the effects of elevated temperature on soil organic carbon content, soil respiration rates, and soil enzyme activities in subalpine Picea asperata plantations, a esimulated warming measure was applied with Open-top chambers. The results were as followed: 1) During the period from Nov. 2005 to Sep. 2007, mean air temperature and soil temperature were respectively 0.43℃ and 0.27℃ the ambient higher. Soil water content decreased to different exent in different months in warmed plots than in unwarned plots at depth of 0-10 cm. 2) In general, elevated temperature enhanced the soil enzyme activities of invertase, protease, and urease. In the first year of warming—after 300 days’ treatment (in Sep,2006), the activities of invertase, protease, and urease increased by 36.36%, 12.90% and 31.37% respectively at the depths of 0-10 cm,among which the activity of invertase reached statistic significance. In the second year of warming, invertase activity increased by 24.31% after 540 days’ treament (in May, 2007), 14.54% after 600 days’ treament (in Jul, 2007) and 7.22% after 660 days’ treatment (in Sep, 2007) at the depths of 0-10 cm, and the differences in July and Septemmber were statistically significant. Elveated temperature also increased the activity of urease in the second year of warming and had significant effects in May and July. The activity of protease in warmed plots was also higher than in unwarmed plots at depths of 0-10 cm, but there was no significant difference. Elevated temperature had no significant effects on all soil enzyme acitivities at the depths of 10-20 cm in the first and sencond year. The values of above-mentioned soil enzyme all decreased with soil layers. 3) Eleavted temperature enhanced the activities of catalase and polyphenol oxidase in the first year of warming while they turned out downtrend in the second year. The activity of catalase increased by 3.76% and 5.54% at depths of 0-10 cm and 10-20 cm respectively in the first year—after 300 days’ warming (in Sep, 2006), the differences of which had no statistical significance. The activity of polyphenol oxidase was significantly increased by 49.25% at depths of 0-10 cm and not significantly increased by 29.67% at depths of 10-20 cm after 300 days’ warming. In the second year of warming, the catalase activity was significantly decreased by 27.70% after 540 days’ treament (in May, 2007) and not significantly decreased by 4.34% and 1.47% after 600 days’ (in Jul, 2007) and 660 days’ treament (in Sep, 2007) respectively. The activities of catalase and polyphenol oxidase at depths of 10-20 cm were decreased to different extent, but there was no significant difference. Catalase activity stepped down with soil layers while polyphenol oxidase activity stepped up. 4) Increased temperature in both the first year and the second year resulted tendency of decrease in the contents of soil organic carbon and soil organic matter, and C/N ratios at soil depths of 0-10 cm and 10-20 cm. However, with the prolonged warming, the tendency of decrease gradually tapered off and the extent of decrease in the second year of experiment were lower than that in the first year. The contents of soil organic carbon and soil organic matter were all decreased 8.69% by warming in the first year and dcreased 4.35%, 3.80% and 2.44% in May, July and September of the second year, but no significant difference were found. The C/N ratios increased 8.52% in the first year of warming and had less increment in the second year, all of which were not statistical significant. Eleveated temperature had no obvious effect on the content of tatol N in two year consecutive warming experiment. The contents of soil organic carbon and soil organic matter, total N and C/N ratios all had the tendency of dcreasing with soil layers. 5) Soil respiration rates were significantly enhanced by 13.32% and 21.17% after 300 days’ (in Sep, 2006) and 360 days’ (in Nov, 2006) treament in the first year of warming, but the same showed no obvious difference in the second year of treatment, which was assumed the adaptability of soil respiration with a certain heightened temperature. Diurnal soil resspiration showed a daily variation with a minimum value between 4:00 and 10:00 h and a maximum value between 14:00 and 20:00 h, coinciding with the minimum and maximum values of soil temperature at 2 cm. Soil respiration rates exhibited a pronounced seasonal variation with minimum values in Novmber and a maximum value in July, approximately coinciding with the seasonal variation of air and soil temperature. An exponential function provided the best fit for soil respiration with temperature while a quadric equation was used to estimate the effect of soil moisture on soil respiration, which were all significantly correlated. Soil respiraion rate was more highly correlated with the soil temperature than soil moisture.

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First principles calculations are performed to investigate the elastic and electronic properties of MFe3N (M=Co,Rh,Ir) at Pm-3m space group. The authors' calculation indicates that the three MFe3N phases are metallic and mechanically stable. For RhFe3N, the calculated lattice parameter of 3.826 A is in excellent agreement with the experimental value of 3.8292 A. The three phases are ferromagnetic with the calculated magnetic moments per f.u. being 8.92 mu(B) for CoFe3N, 9.04 mu(B) for RhFe3N, and 8.50 mu(B) for IrFe3N. The unusually large B/G ratio from 2.47 for CoFe3N and 2.45 for RhFe3N to 1.81 for IrFe3N indicates that they are ductile.

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Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone that plays key roles in the folding, maintenance of structural integrity and regulation of a subset of cytosolic proteins. In the present study, the cDNA of Argopecten irradians HSP90 (designated AiHSP90) was cloned by the combination of homology cloning and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of AiHSP90 was of 2669 bp, including an open reading frame (ORF) of 2175 bp encoding a polypeptide of 724 amino acids with predicted molecular weight of 83.08 kDa and theoretical isoelectric point of 4.81. BLAST analysis revealed that AiHSP90 shared high similarity with other known HSP90s, and the five conserved amino acid blocks defined as HSP90 protein family signatures were also identified in AiHSP90, which indicated that AiHSP90 should be a cytosolic member of the HSP90 family. Fluorescent real-time quantitative PCR was employed to examine the expression pattern of AiHSP90 mRNA in haemocytes of scallops challenged by Gram-negative bacteria Vibrio anguillarum and Gram-positive bacteria Micrococcus luteus. In both bacterial challenged groups, the relative expression level of AiHSP90 transcript was up-regulated and reached maximal. level at 9 h after injection, and then dropped progressively to the original level at about 48 h post challenge. The results indicated that AiHSP90 was potentially involved in the immune responses against bacteria challenge in scallop A. irradian. (c) 2007 Elsevier Ltd. All rights reserved.

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A continuous long (224m) and high-resolution core TY2 was recovered from paleo-maar-lake Tianyang, tropical South China. Based on the diatom records of the upper 130-m core, this paper focuses on exploring climate change and the lake evolution history in tropical South China during the past 240ka. The most typical and unique characteristics of the diatom assemblages is that, Aulacoseira granulata was dominant or absolutely dominant species (80-90%) during most parts of the 130-m core, while Cyclotella stelligera var. tenuis and Fragilaria construens var. venter were subdominant species in only limited parts of the lower and upper core, respectively. Time scale is always the biggest problem for the study of TY2 core, so although diatom is seldom used for establishing time scale, here we attempt this by correlating the diatom-reconstructed temperature sequence with the time scale of ODP core 806B from Equatorial Western Pacific. Verified by the few most reliable ages from TY2 core and the parallel core TYl, a rather reasonable and reliable time scale was established. 01S 7/6 falls at the depth of 100m (ca. 194kaBP), OIS 6/5 at 75m (ca. 132kaBP), OIS 5/4 at 46m (ca. 75kaBP), OIS 4-3 at 35m (ca. 60kaBP). Qualitative and quantitative environmental reconstructions are made on the basis of diatom assemblage ecotype and EDDI dataset. Correlation of diatom-reconstructed temperature and moisture changes of Core TY2 with pollen-reconstructed temperature and rainfall sequence of Core TYl proves that the results are quite consistent in most periods. Thus the reconstruction results from diatom are quite reliable, and probably have a much higher resolution than pollen results. Combined with lithological and magnetic susceptibility variations, the diatom analysis reveals that, the general climate in tropical South China during the past 240ka was warm and wet. On the time scale of glacial-interglacial, warm and wet, cool and dry are not always synchronous. It was relatively warm-wet during the penultimate interglacial, cool-dry during the penultimate glacial, warm-dry during the last interglacial, and cooler-drier during the last glacial. In contrast, on the time scale of subglacial-subinterglacial scales, warm and dry, cool and wet corresponds very obviously, showing very clear 21-23 ka precession cycle. Analysis also shows that, the water of Tianyang paleo-maar-lake was generally warm, turbulent, turbid, meso-trophic, slightly alkaline, low conductivity and fresh during the past 240 kaBP, with small variations in some parts. Tianyang paleolake experienced shallow to semi-deep lake in OIS7d, open shallow lake in OIS7c-OIS5b, shallow coastal lake in OIS5a-OIS4c, swamp in OIS4b, and then completely dried up in OIS3c. The lake evolution was mainly controlled by temperature and precipitation changes in tropical China. While temperature and precipitation changes were probably controlled by the migrations of monsoon rainband and the evaporation rate, which was in turn controlled by the evolution of East Asian monsoon. Therefore, when the summer monsoon was strongest the climate was warm-dry, when stronger the climate was warm-wet; when the winter monsoon was strongest the climate was cool-dry, stronger cool-wet. This mechanism caused the warm-dry sub interglacial and cool-wet subglacial climate in the tropical South China.

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A novel stress-strain relation with two stages of linear elastic deformation is observed in [0 0 0 1]-oriented ZnO nanorods under uniaxial tensile loading. This phenomenon results from a phase transformation from wurtzite (WZ, P6(3)mc space group) to a body-centered tetragonal structure with four-atom rings (denoted as BCT-4) belonging to the P4(2)/mnm space group. The analysis here focuses on the effects of nanorod size and temperature on the phase transformation and the associated mechanical behavior. It is found that as size is increased from 19.5 to 45.5 angstrom, the critical stress for nucleation of the transformation decreases by 25% from 21.90 to 16.50 GPa and the elastic moduli of the WZ- and BCT-4-structured nanorods decrease by 24% (from 299.49 to 227.51 GPa) and 38% (from 269.29 to 166.86 GPa), respectively. A significant temperature effect is also observed, with the critical stress for transformation initiation decreasing 87.8% from 17.89 to 2.19 GPa as temperature increases from 300 to 1500 K. (c) 2007 Elsevier B.V. All rights reserved.

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In the present study, peel tests and inverse analysis were performed to determine the interfacial mechanical parameters for the metal film/ceramic system with an epoxy interface layer between film and ceramic. Al films with a series of thicknesses between 20 and 250 mu m and three peel angles of 90 degrees, 135 degrees and 180 degrees were considered. A finite element model with the cohesive zone elements was used to simulate the peeling process. The finite element results were taken as the training data of a neural network in the inverse analysis. The interfacial cohesive energy and the separation strength can be determined based on the inverse analysis and peel experimental result.

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In this paper, a series of experiments have been conducted in a U-shaped oscillatory flow tunnel, which provides a more realistic simulation than the previous actuator loading methods. Based on the experimental data of pipe displacement with two different constraint conditions (freely laid pipelines and anti-rolling pipelines), three characteristic times in the process of pipeline losing stability are identified. The effects of sand size on the pipeline lateral stability are examined for freely laid pipelines. The empirical relationships between non-dimensional pipeline weight (G) and Fronde number (Fr-b) are established for different constraint conditions, which will provide a guide for engineering practice. (C) 2002 Elsevier Science Ltd. All rights reserved.

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Bends are widely used in pipelines carrying single- and two-phase fluids in both ground and space applications. In particular, they play more important role in space applications due to the extreme spatial constraints. In the present study, a set of experimental data of two-phase flow patterns and their transitions in a 90degrees bend with inner diameter of 12.7 mm. and curvature radius of 76.5 mm at microgravity conditions are reported. Gas and liquid superficial velocities are found to range from (1.0 similar to 23.6) m/s for gas and (0.09 similar to 0.5) m/s for liquid, respectively. Three major flow patterns, namely slug, slug-annular transitional, and annular flows, are observed in this study. Focusing on the differences between flow patterns in bends and their counterparts in straight pipes, detailed analyses of their characteristics are made. The transitions between adjoining flow patterns are found to be more or less the same as those in straight pipes, and can be predicted using Weber number models satisfactorily. The reasons for such agreement are carefully examined.

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<正> 国际尖端材料技术协会(SAMPE:Society for the Advancement of Material and Process Engineering)于1992年10月20—22月在加拿大多伦多市召开了两个国际学术会议:第24届国际SAMPE技术会议(24th Int.SAMPE Techn。Coaf。)和第3届国际金属与金属加工会议(3rd Int.SAMPE Metals and Metals Processin Conf.)。两个会议同时举行,全体会议(Plenary Session)在一个会场举行。前者的主题是“先进材料迎接经济的挑战”;后者的主题是“合成与加工的新进展”.尽管此二会议是在西方发达国家经济很不景