67 resultados para C ... f, B ... n.
em Chinese Academy of Sciences Institutional Repositories Grid Portal
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臭氧层损耗导致的地球表面UV-BUV-BUV-B UV-BUV-B 本文以青藏高原东缘亚高山针叶林主要树种云杉为研究对象,研究云杉种子萌发及幼苗的生长和生理对UV-BUV-BUV-lamp)来模拟增强的UV-B OTCs)来模拟气候变暖。本试验包括四个处理:(1UV-B 辐射+C2)大气UV-B +模拟气候变暖(W3UV-B辐射+U4)增强的UV-B+U+W 根据本试验结果,UV-BUV-BMDAUV-B照射处理萌发云杉幼苗两年后,幼苗的生长受到显著抑制。我们的结果显示,OTCs10 cm)和土壤(5 cm1.740.94 根据本试验结果,温度升高显著地促进了增强UV-BUV-BUV-B辐射增强处理下幼苗的抗氧化系统活性改善的结果。温度升高还缓解了高UV-BUV-BU+WUV-B辐射联合(C)处理,表现为株高、地径、根长和生物量积累均高于C处理,因此可以推断,UV-BUV-B 同样,增强的UV-BPn)和表观量子效率(ΦPSII的光抑制。增强的UV-BII(PSIIUV-BPSII光化学效率的提高。此外,温度升高还缓解了UV-B Enhanced UV-B radiation due to the reduction of O3 layer and global warming induced by increased greenhouse gases in the air have become the two pressing aspects of global climate changes. Moreover, enhanced UV-B radiation and warming have profound and long-term impacts on terrestrial plants and ecosystems, and the studies focusing on the two factors have attracted many attentions. Qinghai-Tibetan Plateau is the third in elevation in the world, and enhanced UV-B radiation and climate warming are especially prominent in this region. Our research located in the main forest belt in the eastern Qinghai-Tibetan Plateau where large areas of subalpine coniferous forests distributed. Based on that, we carried out a research to study the effects of enhanced UV-B radiation and climate warming on seed germination and seedlings growth of seedlings which are the important basic stage in forest regeneration. This research was arranged by a complete factorial design and included two factors (UV-B radiation and temperature) with two levels. The UV-lamps were used to manipulate the supplemental UV-B radiation and open-top chambers (OTCs) were adopted to increase temperature. The four treatments were: (1) C, ambient UV-B without warming; (2) U, enhanced UV-B without warming; (3) W, ambient UV-B with OTCs warming; (4) U+W, enhanced UV-B with OTCs warming. The main results were exhibited as follows: 1. Based on our results in this research, OTCs increased temperature on average 1.74℃ in air (10 cm above ground) and 0.92 in soil (5 cm beneath ground). Furthermore, OTCs also slightly reduced soil moisture and relative air humidity, however, the differences was not statistically significant. 2. Our results showed that enhanced UV-B had no significant effects on the seeds germination of P. asperata. Enhanced UV-B affected sprouts of P. asperata until the needles unfolded. During two years, enhanced UV-B inhibited the efficiency of the antioxidant defense systems, and as a result, it induced oxidant stress and the accumulation of MDA in needles. After two years of exposure to enhanced UV-B, the growth of P. asperata sprouts was markedly restrained compared with those under ambient UV-B radiation and temperature (C). Warming significantly stimulated the germination speed and increased the germination rate of P. asperata seeds. In the next place, it prominently facilitated the growth of P. asperata sprouts, represented as improvements in stem elongation and biomass accumulation. Furthermore, warming also increased root growth of P. asperata sprouts, which could made sprouts more efficient to use water and nutrient elements in soil. In this research, warming alleviated the deleterious effects of enhanced UV-B on P. asperata sprouts. It markedly stimulated the growth of P. asperata sprouts exposed to enhanced UV-B. The ease effects of warming on the abilities of the antioxidant defense systems might account for its amending effects on growth. After two years of exposure to enhanced UV-B radiation and warming, the growth of P. asperata sprouts was better than those under ambient UV-B radiation without warming (C), which could be seen from the higher plant height, basal diameter, root length and total biomass accumulation compared with C. 3. Enhanced UV-B radiation significantly influenced the photosynthesis processes of two-year old P. asperata seedlings. Our results showed that enhanced UV-B reduced the net photosynthetic rate (Pn) and the apparent quantum efficiency (Φ), and induced photoinhibition of photosynthetic system II (PSII). Enhanced UV-B significantly decreased the concentration of nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and zinc (Zn), however, it increased the accumulation of iron (Fe) in the whole plant of P. asperata seedlings. Warming significantly stimulated Pn of P. asperata seedlings but it had no prominent impacts on the photochemical efficiency of PSII. In our research, warming also alleviated the harmful effects of enhanced UV-B on photosynthesis and absorption of ions of P. asperata seedlings. It increased Pn, Φ and the photochemical efficiency of PSII in seedlings exposed to enhanced UV-B. Moreover, warming also increased the absorption of ions of the seedlings exposed to enhanced UV-B radiation.
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本文以EVAc共聚物为例,EV共聚物序列结构的符号表示与Bovey(Ⅰ),EVSung,在二元组和三元组序列水平上分析了EV13Sung,与取代基参数,~(13)C NMR13个谱峰之间的一一对应关系。其主要内容由Sungα~S_1,β~S_2,γ~S_3,δ~S_4,δ~+0ppm对应关系表征,EV共聚物的~(13)C NMR,EV
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在1,2-,(—CH_2—)gauche,gauche,因此主链叔碳对化学位移的贡献对于仲碳谱有着决定性的影响。相比之下,γ_1=—6.376.41ppm_2=0.01.56ppm,均方误差MSE分别是0.16610~(-2)0.364×10~(-2)ppm~2。本文同时讨论了模型链的种类、链长以及温度对键概率的影响。并指出有个别反常的情况发生。文中还对间同1,2-
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On the basis of the pseudopotential plane-wave (PP-PW) method in combination with the local density functional theory (LDFT), complete stress-strain curves for the uniaxial loading and uniaxial deformation along the [001] and [111] directions, and the biaxial proportional extension along [010] and [001] for aluminium are obtained. During the uniaxial loading, certain general behaviours of the energy versus the stretch and the load versus the stretch are confirmed; in each case, there exist three special unstressed structures: f.c.c., b.c.c., and f.c.t. for [001]; f.c.c., s.c., and b.c.c. for [111]. Using stability criteria, we find that all of these states are unstable, and always occur together with shear instability, except the natural f.c.c. structure. A Pain transformation from the stable f.c.c. structure to the stable b.c.c. configuration cannot be obtained by uniaxial compression along any equivalent [001] and [111] direction. The tensile strengths are similar for the two directions. For the higher energy barrier of the [111] direction, the compressive strength is greater than that for the [001] direction. With increase in the ratio of the biaxial proportional extension, the stress and tensile strength increase; however, the critical strain does not change significantly. Our results add to the existing ab initio database for use in fitting and testing interatomic potentials.
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<> 为什么十七世纪以前没有真正的“科学”? ,希腊文化曾经有过高度的发展。阿基米德(287212,B.C.),(300,B.C.),都是杰出的科学先驱例子。但是最有影响的亚里士多德(384322,B.C.),,他的思想整整统治了西方经院学派达两千年之久,
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利用霍普金森扭杆(TorslonalSplit-HopkinsonBar)-锂合金材料的动态应力--1300s~(-1)到2600s~(-1),,三种不同成份或状态的铝-,,随应变率的增加,
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本文基于第一原理的能量计算和稳定性理论,研究了双原子组分材料β-SiC在各种载荷方式下的力学性质:弹性行为、应力-应变关系、稳定性和强度。由于沿[111]Si-C键是不等价的,所以有相对内位移出现。本文的分析揭示了如下事实:当载荷较小时,内位移的影响不明显;当载荷较大时,影响则越来越显著;裂纹在{111}shuffle面上成核,并最终导致材料以解理的形式破坏。在沿[001]spinodalBorn[001][111]方向单轴加载和单轴应变、及沿[010][001][001]方向的单轴加载情况下的稳定性及分叉行为。研究结果表明,除了自然的面心立方结构外,所有其它的、应力自由的立方结构都是不稳定的。对于铝而言,稳定的面心立方结构不能从沿任何等价的[001][111]KRbCs在如下四个结晶面上外延成长的行为,即{001}{110}{111}和{201}{110}{001}和{111}b.c.c.{201}面存在一个亚稳态,是一个超结构,。亚稳态的存在显著地影响着材料外延成长的软化行为。基于正交变形路径,并考虑了温度的影响以后,解释了实验上观察到的碱金属从h.c.p.结构转变到b.c.c.结构的现象。本文第五章归纳整理在赝势平面波框架下的总能、力和应力在实空间和动量空间的解析表达式,以方便参阅和使用。
Cluster explosion investigated by linearly chirped spectral scattering of an expanding plasma sphere
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Femtosecond explosive processes of argon clusters irradiated by linearly chirped ultraintense laser pulses have been investigated by 90 degrees side spectral scattering. The spectral redshift and blueshift, which correlate with the cluster explosion processes have been measured for negatively and positively chirped driving laser pulses, respectively. The evolution of the heated-cluster polarizability indicates that the core of the cluster is shielded from the laser field in the beginning of the explosion and enhanced scattering occurs after the fast explosion initiates. Evidence of resonant heating is found from the coincidence of enhanced scattering with enhanced absorption measured using the transmitted spectra. Anomalously large-size clusters with very low gas density have been observed in this way and can be used as clean and important cluster targets.
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We investigated the effect of cerium oxide on the precipitation of Ag nanoparticles in silicate glass via a femtosecond laser irradiation and successive annealing. Absorption spectra show that Ce3+ ions may absorb part of the laser energy via multiphoton absorption and release free electrons, resulting in an increase of the concentration of Ag atoms and a decrease of the concentration of hole-trapped color centers, which influence precipitation of the Ag nanoparticles. In addition, we found that the formed Ag-0 may reduce Ce4+ ions to Ce3+ ions during the annealing process, which inhibits the growth of the Ag nanoparticles.
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该成果收集了近10576525a) CAMPEPCKCAM-PEPCKPEPCK是其光下C4PEPCK受底物和碳代谢中间产物的调控,纯化酶的负效应剂G6P、FBP、PEP及正效应剂Mn2+b)首先指出PEPC也是活性氧攻击的靶蛋白,其失活原因在于酶蛋白氧化降解和构象改变。不同光合途径植物对光氧化的敏感性有别。光氧化条件下C3C4植物产生.O2- PSII稳定性有一定差异。脂氧合酶(LOX)抑制光合电子传递的位点在PSIIQPQc)指出较强的抗氧化能力(清除自由基能力)、抗UV-BUV-BO2NO2-d)δ13C分析追踪了前80CO20.7~2.3μl/L/年)。对森林中不同人类活动干扰地点大气CO2NOXSO2CO2CO24个品种,并从多种指标证明高CO2e)DPPH.
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稻属(Oryza L.Oryzeae DumortierAA,BBBBCC,CC,CCDDEEFF,GGHHJJ和HHKKOryza officinalis复合体包括BBBBCC,CC,CCDDEE Oryza officinalis复合体中基因组研究的历史和现状,用基因组原位杂位(GISH;B,C,DE . 原杂交方法的研究:1;/空气干燥法(Fukui et al., 1992)加以改进后,特别适宜于小染色体植物材料的制片。2-20 70%8个月以内的根尖材料,可用于原位杂交;-20 18DNAGISH3)探针标记:比较了随机引物法、缺口平移法和两步标记法(先用随机引物标记后,再用缺口平移法进行标记的方法)的优缺点。结果显示两步标记法是最佳标记方法。 . GISHOryza minutaScilla sinensis (2n = 34)1)用二倍体亲本基因组之一做探针而不用封阻DNA, Oryza minutaScilla sinensis2Scilla sinensis;DNA3)同时用两个亲本的DNA做探针,不仅能够有效分辨不同的基因组,还能够根据交叉杂交程度推测基因组间的分化程度,是鉴别异源多倍体最有效的方法。 . GISH1Oryza minuta, O. punctata和O. malampuzhaensis的基因组的组成都为BBCC。2Oryza minutaBO. punctataB3)O. altaCCDDC和D . GISHBC,DE1)BC;ECE和BEC之间的分化比ED;C和D
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藻胆体在低浓度磷酸缓冲溶液中发生解离,我们通过藻胆体在解离过程中荧光发射光谱的变化研究藻胆体中藻胆蛋白之间的光能传递. 1(Nostoc flagelliforme)藻胆体在0.9M77KF686-B686nm,还出现F648F666F648先于F666C-藻蓝蛋白(F'648)-B,并说明藻蓝蛋白与别藻蓝蛋白之间的断裂先于别藻蓝蛋白与别藻蓝蛋白-B648nm686nm.而666nmC--B.我们因此提出在该藻胆体中藻胆蛋白之间的光能传递途径如下: CC-_-别藻蓝蛋白-B C-藻蓝蛋白与别藻蓝蛋白相连接,另一部分与别藻蓝蛋白-B 2( synechococcus leopoliensis 625)0.6M,0.3M0.1M77K-B(F'684)C-(F655)(F666)C-藻蓝蛋白传给别藻蓝蛋白-B-B-B的复合物,此复合物在0.lM0,6M c-藻红蛋白→c—藻蓝蛋白—①别藻蓝蛋白--B复合物、②别藻蓝蛋白-B
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真菌病害是造成采后新鲜水果损失的一个主要原因。生物拮抗菌能有效地防治果实采后腐烂,降低杀菌剂的用量,从而增加了食品安全性和降低了潜在的环境危害。然而,与化学杀菌剂相比,单独使用生物拮抗菌对果实采后病害的控制效果有时不如化学杀菌剂明显。因此,为了提高拮抗菌的生防效力,有效控制果实的采后病害,本文主要研究了拮抗菌与化学物质使用的防病机理,并从冬枣果实中克隆β-13-葡聚糖酶基因并对其特性进行了初步分析。研究结果表明: 1. Cryptococcus laurentii和枯草芽孢杆菌Bacillus subtilisC. laurentiiB. subtilisC. laurentiiB. subtilis的伤口上接种病原菌则不增加拮抗细菌的群体数量。 2. DeccozilSportakIprodineStrobyR. glutinis对DeccozilIprodioneStrobyC. laurentii100 l/LStroby2%(w/v)的碳酸氢钠(SBC)与C. laurentiiT. pullulans(Penicillium expansumAlternaria alternata)SBCC. laurentiiT. pullulans 3. C. laurentiiB. subtilis对冬枣果实抗病性的诱导与接种距离和接种时间密切相关。距接种拮抗菌近的部位,抗性诱导就越强。酵母菌诱导果实的这种抗病性与诱导果实几丁质酶,β-13-葡聚糖酶, PALPODPPO 4. 2 mMSA0.2 mMMeJA 并能诱导甜樱桃果实β-13-葡聚糖酶, PAL PODPPOSAMeJA25C-1,3-PAL0C的甜樱桃果实的酶活性。2 mMSA显著抑制了Monilinia fructicola;而0.2 mM的MeJAM. fructicolaMeJA对果实β-13-葡聚糖酶和PAL活性的诱导作用要强于SA 5. 1 × 108CFU/mlC. laurentii5 × 107CFU/mlC. laurentii0.2 mMMeJA 配合使用均可诱导桃果实的抗性,并显著降低果实青霉病和褐腐病的病斑直径。0.2 mM的MeJAC. laurentiiP. expansum的菌丝扩展, M. fructicola250C,MeJAC. laurentiiβ-13-PALPOD 6. PCRβ-13-β-13-cDNAGlu-1Glu-2)。RT-PCR结果表明,Glu-1C. laurentii-1,3-;而Glu-2C. laurentii