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991.
采用简单表面反应模式,对化学气相沉积金刚石薄膜的表面动力学过程进行了研究,得到了金刚石薄膜的沉积速率公式,揭示了影响薄膜生长的因素并由此讨论了金刚石薄膜生长的机制和规律。 相似文献
992.
993.
设置3因素3水平正交设计L9(33)的麻竹肥料试验。其结果表明:(1)施肥对麻竹产量有极显著的增产效应,氮、磷、钾增产的主次顺序为N>P>K。麻竹产量与施肥量回归方程y=84.30X1-86.44X2 152.15X3-0.229X12 0.947X1X2-0.769X22-0.736x1x3 0.953x32 17744(X1:施N量kg/hm2,X2:施P2O5量kg/hm2,X3:施K2O量kg/hm2,Y:产量kg/hm2),且差异达极显著;(2)最佳施肥配比N:P2O5:K=1:0.51:0.58,最大产量为44491.86kg/hm2,对应的年最大产量施肥量为N:228.71kg/hm2,P2O5:115.58kg/hm2,K2O:132.88kg/hm2;(3)施肥对笋中含N、P、K含量有显著影响;(4)施肥对笋中粗蛋白含量影响极显著主次顺序N>P>K 相似文献
994.
近年来,外国对华反倾销愈演愈烈,我国己成为国际反倾销重大受害国和指控对象,因此,构筑由政府、中介组织、企业三位一体的反倾销体系己势在必行。我国要积极应对外
国对华的反倾销,争取主动权。 相似文献
995.
本研究对健康和免疫后接种京毒—1号MD强毒鸡中枢免疫器官中PMG~ 浆细胞的动态变化进行了观察。结果表明:健康攻毒组免疫器官中的PMG~ 浆细胞数在攻毒后3天开始下降,15~20天后迅速回升,30天左右达到峰值,以后又迅速下降;而在免疫攻毒组,免疫器官中的PMG~ 浆细胞数在20天以前一直处于较高的水平,之后和对照组差异不明显。 相似文献
996.
Baines KH Simon-Miller AA Orton GS Weaver HA Lunsford A Momary TW Spencer J Cheng AF Reuter DC Jennings DE Gladstone GR Moore J Stern SA Young LA Throop H Yanamandra-Fisher P Fisher BM Hora J Ressler ME 《Science (New York, N.Y.)》2007,318(5848):226-229
Although lightning has been seen on other planets, including Jupiter, polar lightning has been known only on Earth. Optical observations from the New Horizons spacecraft have identified lightning at high latitudes above Jupiter up to 80 degrees N and 74 degrees S. Lightning rates and optical powers were similar at each pole, and the mean optical flux is comparable to that at nonpolar latitudes, which is consistent with the notion that internal heat is the main driver of convection. Both near-infrared and ground-based 5-micrometer thermal imagery reveal that cloud cover has thinned substantially since the 2000 Cassini flyby, particularly in the turbulent wake of the Great Red Spot and in the southern half of the equatorial region, demonstrating that vertical dynamical processes are time-varying on seasonal scales at mid- and low latitudes on Jupiter. 相似文献
997.
东北红豆杉天然群体插穗生根力变异及扦插技术 总被引:10,自引:0,他引:10
采用扦插繁殖的方法,对东北红豆杉不同群体之间的插穗生根率、每穗生根条数、最长根长进行了研究。结果表明:三者之间均存在极显著差异。群体内插穗生根能力的变异幅度与群体间相同。插穗生根率、每穗根条数、最长根长三者之间存在着显著或极显著的相关性。以腐殖土为扦插基质、提高插床温度(20—23℃)、生长调节物质处理等可提高插穗生根率。不同插穗类型之间,插穗生根率无显著差异,3、4年生枝条扦插后,根系发达,成苗率高。 相似文献
998.
AIM: To investigate the protective role of heat-shock protein 70 (HSP70) in the pathogenesis of gastric mucosal damage in cirrhotic rats with portal hypertensive gastropathy (PHG).METHODS: The rat model of liver cirrhosis with PHG was established by injection with tetrachloride.The animals were divided into normal control group, PHG group, PHG+heat treatment group, PHG+BPI21 group and PHG+endotoxin groups.The endotoxin used in the experiment was at the dose of 3 mg/kg and endotoxin antagonist BPI21 was at the dose of 2 mg/kg.HSP70 was induced by pre-treating the animals with mild whole-body heating.The levels of HSP70 and tumor necrosis factor alpha (TNF-α) in the gastric mucosa were measured by ELISA.Furthermore, the pathological changes of the gastric mucosa were observed under microscope with HE staining.RESULTS: Compared with the normal control rats, the rats in PHG group showed obvious gastric pathological lesion, decrease in HSP70 production and increase in TNF-α level in the gastric mucosa, and increased endotoxin concentration in the plasma.Compared with PHG+endotoxin group, the gastric mucosal lesion in PHG+BPI21 group was significantly attenuated, accompanied by the increase in HSP70 production and decrease in TNF-α level in the gastric mucosa.Heat treatment increased HSP70 production and decreased TNF-α concentration in the PHG rats, thus attenuating the gastric mucosal damage.CONCLUSION: HSP70 alleviates the gastric mucosal lesion induced by endotoxin in cirrhotic rats with PHG and decreases the concentration of TNF-α in gastric mucosa, indicating a protective role of HSP70 in the pathogenesis of gastric mucosal damage in PHG. 相似文献
999.
Yang H Pang W Lu H Cheng D Yan X Cheng Y Jiang Y 《Journal of agricultural and food chemistry》2011,59(5):2069-2076
The metabonomics changes of plasma and brain tissue after dietary supplementation with blueberry extracts (BBE) and cyanidin-3-O-galactoside from blueberry (BBM) in aged mice were investigated by (1)H NMR technique. The mice received intragastric administration of BBE (200 mg/kg/day), BBM (50 mg/kg/day), and saline water (0.9%) for 6 weeks, respectively, in the BBE, BBM, and control groups. At the end of the experiment, plasma and brain samples were collected for NMR analysis. The results demonstrated that the level of choline in plasma from BBE and BBM groups were obviously elevated relative to the control group, whereas the levels of lactate and phosphocholine in plasma were remarkably reduced. Compared with those in the control group, the levels of choline and GABA in the brain from the BBE group were obviously increased, whereas glutamate and phosphocholine in the BBE group were significantly decreased. The level of taurine in the brain from the BBM group was particularly higher than that in the control group. These results indicated supplementation with BBE or BBM might induce similar changes of endogenous plasma and brain metabolic profiles in aged mice. 相似文献
1000.
Peng C Chan HY Huang Y Yu H Chen ZY 《Journal of agricultural and food chemistry》2011,59(5):2097-2106
Apple polyphenols (AP) are an excellent source of dietary antioxidants. The present study investigated the effect of AP on the lifespan of fruit flies and their interaction with gene expressions of superoxide dismutase (SOD), catalase (CAT), methuselah (MTH), Rpn11, and cytochrome c oxidase (CcO) subunits III and VIb. Results showed the mean lifespan was significantly extended by 10% in fruit flies fed the AP diet. This was accompanied by up-regulation of genes SOD1, SOD2, and CAT and down-regulation of MTH in the aged fruit flies. Paraquat and H(2)O(2) challenge tests demonstrated that AP prolonged the survival time only for Oregon R wild type flies but not for SOD(n108) or Cat(n1) mutants, in which either SOD or CAT was knocked out. Chronic paraquat exposure could shorten the maximum lifespan from 68 to 31 days and reduce the climbing ability by 60%, whereas AP could partially reverse the paraquat-induced mortality and decline in climbing ability. AP could up-regulate Rpn11 at day 30, whereas it appeared to have no significant effect on gene expression of ubiquitinated protein, CcO subunits III and VIb. These AP-induced changes were unlikely associated with caloric restriction as the gustatory assay found no difference in average body weight and stomach redness index between the control and AP fruit flies. It was therefore concluded that the antiaging activity of AP was, at least in part, mediated by its interaction with genes SOD, CAT, MTH, and Rpn11. 相似文献