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831.
初始应力条件对压实黄土动强度影响的研究   总被引:1,自引:0,他引:1  
建筑物地基或土坡中的土体在受到地震或其他动荷载作用前往往处于复杂的初始应力状态,对原有的DTC-199型周期扭转荷载三轴仪进行简单的改造后,可以进行压实黄土在这种固结应力状态下动强度的试验研究。试验结果表明,在其他初始固结应力条件不变时,初始主应力方向角α0对压实黄土的动强度具有显著的影响,初始中主应力系数b0对动强度的影响较小;随着α0的增大,动强度逐渐降低,并在α0 = 90o时达到最小值,最大降幅在40 %左右;b0对压实黄土的动强度的影响具有放大效应和区间效应,b0从0增大至0.5时,动强度逐渐增大,b0从0.5增大至1时,动强度逐渐减小,增加的幅度小于降低的幅度约5 %。  相似文献   
832.
梁昌玉  李晓  吴树仁 《岩土力学》2016,37(12):3472-3480
能量相互转化过程的综合作用导致了岩石破坏,而其破坏的根本原因是岩石中储存的应变能的释放。对中低应变率加载条件下岩石尺寸效应能量特征的研究结果表明:花岗岩破坏时吸收的总能量U、弹性应变能Ue以及损伤应变能Ud均随试件尺寸的增长而降低;岩石强度与岩石中储存的能量有关,尤其与弹性储能有关,即弹性应变能愈高,岩石强度越大;试件长度由50 mm 变为125 mm时,弹性储能逐渐降低,岩石破坏形态从劈裂破坏变为剪切破坏,大尺寸时局部化变形明显。能量是不同应变率加载条件下岩石破坏细微观及宏观特征存在差异的内在动力;亦是导致岩石强度存在尺寸效应的本质动因。  相似文献   
833.
皮肤镜图像分析技术在育发类产品的功效评价研究   总被引:2,自引:0,他引:2  
目的:探讨皮肤镜图像分析技术在育发类产品的功效评价。方法:随机收集雄激素性脱发患者58例,经知情同意后自愿参加产品试用者;取得0周、4周、8周和12周的宏观和皮肤镜微观图像,经观察测得靶目标终毛根数和终毛数密度参数的变化;设实验组与对照组,经自身对照评价其功效。结果:实验组32例,有效率84.37%;对照组22例,有效率86.36%;实验组和对照组的各周次与0周次及两组间比较,产品功效随着时间的推移其各组参数变化均具有显著意义,P0.01。结论:本文采用皮肤镜图像分析技术,客观评价了毛发的生长情况及应用于育发类产品的功效评价,并探讨了皮肤镜的功效判定标准,在临床获得满意的结果;本研究具有无创性、客观性和操作简便的特点,可作为毛发的基础研究和育发类产品功效评价的辅助工具。  相似文献   
834.
应用生物吸附剂技术处理中低放废液的研究   总被引:1,自引:0,他引:1  
利用高担子菌所含壳多糖的强吸附性能研制成功的生物吸附剂,以其具有对放射性核素的强选择性吸附能力、减容效果好和显经济效益的优势,可用于处理中低放废液。迄今,已应用于对切尔诺贝利核事故核心区和若干核电站正常运行产生的核废液的处理,在俄罗斯、乌克兰、法国、芬兰等国家的应用研究中效果显。我国自1999年引进该项技术以来,通过对BR厂YG废液和SG废水的吸附小试,验证了该吸附剂对Cs与sr的吸附能力,查明了应用该生物吸附剂技术的最佳条件。目前,正积极筹备对SG废水的扩大规模台架试验。该项技术具有极良好的应用前景。  相似文献   
835.
Kinetics and products of the gas-phase reactions of dimethylsulphide (DMS), dimethylsulphoxide (DMSO) and dimethylsulphone (DMSO2) with Br atoms and BrO radicals in air have beeninvestigated using on-line Fourier Transform Infrared Spectroscopy (FT-IR) as analytical technique at 740 ± 5 Torr total pressure and at 296 ± 3 K in a480 L reaction chamber. Using a relative rate method for determining the rate constants; the following values (expressed in cm3molecule–1 s–1) were found: kDMS+Br = (4.9 ±1.0) ×10–14, kDMSO + Br < 6 × 10–14,kDMSO 2 + Br 1 × 10–15,kDMSO + BrO = (1.0 ± 0.3) × 10–14 andkDMSO 2 + BrO 3 × 10–15 (allvalues are given with one on the experimental data). DMSO, SO2, COS, CH3SBr andCH3SO2Br were identified as the main sulphur containing products of the oxidation of DMS by Br atoms. From the reaction between DMSO and Br atoms, DMSO2and CH3SO2Br were the only sulphur containing products thatwere identified. DMSO, DMSO2 and SO2 were identified as themain sulphur containing products of the reaction between DMS and BrO.DMSO2 was found to be the only product of the reaction between DMSO and BrO. For the reactions of DMSO2 with Br and BrO no products were identified because the reactions were too slow.The implications of these results for atmospheric chemistry are discussed.  相似文献   
836.
Products of the gas-phase reaction of the NO3 radical with thiophene have been investigated using different experimental systems. On the one hand, experiments have been conducted in our laboratory using two different methods, a Teflon static reactor coupled to a gas chromatograph combined with mass-spectrometry (GC-MS) and a discharge flow tube with direct MS spectroscopic detection. A qualitative analysis in these cases indicates that possible products for the reaction of thiophene+NO3 at room temperature include: sulphur dioxide, acetic and formic acids, a short-chain aldehyde, 2-nitrothiophene and 3-nitrothiophene. On the other hand, quantitative experiments have been performed in the European Photoreactor (EUPHORE) in Valencia, Spain. In this case, the major products were: HNO3 (≈80%), nitrothiophenes (≈30%), SO2 (≈20%), propanal (3%) and a fraction of particles (≈10%). The results obtained indicate that at least 70% of the reaction of NO3 with thiophene proceeds by an H-abstraction process at room temperature. The mechanism of the reaction studied is proposed on the basis of experimental results.  相似文献   
837.
Extracellular products(ECP)produced by Vibrio anguillarum strain M3 originally isolated from diseased flounder(Paralichthys olivaceus)were prepared.ECP of M3 showed gelatinase,casinase,amylase and haemolytic activity on agarose plates.High protease activity against azocasin was detected.Bacterium M3 showed highest growth and protease activity at 25℃。The Protease present in ECP showed maximal activity at pH 8 and 55℃;was completely inactivated by application of 80℃ heat for 30 min;was completely inhibited by EDTA and HgCl2,and was partially inhibited by PMSF,SDS,MnCl2 and iodoacetic acid;but not inhibited by CaCl2 and MgCl2.The ECP was toxic to flounder fish at LD50 values of 3.1 μg protein/g body weight.The addition of HgCl2 and application of heat at 50℃ decreased the lethal toxicity of ECP.When heated at 100℃,ECP lethality to flounder was completely in-hibited.After intramuscular injection of ECP into flounder,it showed evident histopathological changes including necrosis of muscle,extensive deposition of haemosiderin in the spleen,dilated bolld vessels congested with numerous lymphocytes in the liver.These results showed that ECP protease was a lethal factor produced by the baterium V.anguillarum M3.  相似文献   
838.
Incorporation of 14C-bicarbonate into the major intracellular end-products of photosynthesis (protein, polysaccharide, lipid) and two classes of exoproducts (oligomers and polymers) was measured in Belgian coastal waters at different stages of the spring phytoplankton bloom, entirely dominated by the alga Phaeocystis poucheti. It was shown that intracellular protein synthesis contributed 20–42% of the total intracellular 14C fixed and was positively correlated with the inorganic nitrogen content of the surrounding medium. The decrease of protein synthesis following nitrogen depletion is balanced by an increase of intracellular polysaccharide synthesis, which varies from 22 to 42% of the intracellular 14C fixed, and by an increase in extracellular release of high molecular weight material (18–60% of total 14C fixed) which forms a mucous envelope where cells are embedded. Lipid synthesis is not correlated with the ambient inorganic nitrogen content and represents a rather constant proportion (about 20%) of the intracellular 14C fixed.  相似文献   
839.
分析了数字栅格地图制作过程中的误差来源和类型,提出了一套能够同时改正系统和局部几何畸变的制作方法和流程,开发了半自动、高精度的制作软件系统。  相似文献   
840.
吴炳友  姜华 《现代测绘》2005,28(4):17-18
通过对“允许偏离”的分析,说明“允许偏离”在测绘产品、测绘仪器检测、检定中的应用,如何保证质量而实事求是解决问题。  相似文献   
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