994 resultados para 7136-401


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The aim of this paper is to investigate the mechanism of small scale sand-wave migration. According to the environmental characteristic of the north gulf of South China Sea, a quasi-3D mechanics model has been built for simulating the small scale sand wave migration. The calculation results are shown to be consistent with the observed data in the trough of sand ridge. Considering the effect of environmental actions and sand wave features, we develop an effective formula to predict sand-wave migration. It is indicated that the physical models should be used to predict the migration of the small scale sand-wave, which is rarely dominated by wave activity.

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A high current RFQ (radio frequency quadrupole) is being studied at the Institute of Modern Physics, CAS for the direct plasma injection scheme. Shunt impedance is air important parameter when designing a 4-rod RFQ cavity, it reflects the RF efficiency of the cavity, and has a direct influence on the cost of the structure. Voltage distribution of a RFQ cavity has an effect on beam transmission, and particles would be lost if the actual voltage distribution is not as what, it should be. The influence of cell length, stern thickness and height on Shunt impedance and voltage distribution have been studied, in particular the effect of projecting electrodes has been investigated in detail.

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本工作研究了四种不同形状和尺寸的石英管对1100eV、1300eV、1500eV三种能量电子束的导向作用,并把四种实验结果进行了分析对比。四种石英管分别为等径圆柱形弯曲管、等径圆柱形直管、直锥形管以及弯曲锥形管,它们的内径均在毫米量级。实验中利用一个位置灵敏法拉第筒对从石英管出射的电子束进行探测,获得从管道中出射的电子束流强度在位置灵敏法拉第筒各道上的强弱分布,其结果显示宏观尺寸石英管对电子束存在导向作用。对于等径圆柱形石英管,入射电子束流的强度越强,其导向作用越明显;然而对于锥形管,导向作用并不明显,且不随入射电子束流强度增加有明显的变化。此外,实验结果在一定程度上显示出石英管对中低能电子束的导向能力并不取决于管的形状。石英管导向能力与管的尺寸、形状及材料之间的关系还有待进一步的研究

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本人建立了一台塑料闪烁体β射线望远镜,该望远镜由工作在符合状态的ΔE探测器和E探测器构成。ΔE探测器由ST-401型塑料闪烁体薄片(Φ 25 * 0.5)构成,用来甄别掉γ射线。E探测器由ST-401型塑料闪烁体(Φ 70 * 70,异形)构成,在跟ΔE探测器符合的条件下,用来测量β谱。光电倍增管均采用GDB-50L型。用该望远镜测量了~(207)Bi 991KeV内转换电子谱,在没有扣除电子到达E探测器闪烁体前Ni窗、E闪烁体和空气对峰的展宽的条件下,主峰分辨为38%。作为对β连续谱测量和处理方法的检验,测量了~(90)Sr-~(90)Y源的β连续谱,并且对该谱用迭代的“展开法”进行了处理。另一方面,本文还利用费米球模型,对重离子核反应类弹产物动量分布宽度进行了计算

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C-6-carboxylated chitosan obtained by oxidation of chitosan was selectively modified in order to obtain derivatives similar to bacterial antigens. Selective O-acetylation of 6-carboxyl chitosan afforded a modified polysaccharide with the 2-amino group available for further modifications to create carbonyl groups. A deaminative degradation reaction allowed the formation of oligosaccharides with terminal aldehyde groups. Reductive alkylation with lactose introduced lactityl branches which were oxidized with galactose oxidase to give aldehyde groups in its -galactose residues.

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Chinese Acad Sci, ISCAS Lab Internet Software Technologies

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对污水的生态处理原理进行扼要论述 ,对污水的生态处理技术体系进行较为全面地概括 ,并就目前的应用条件与适用范围进行了阐述 ,在简要回顾污水的生态处理技术发展历史的基础上对该领域今后的发展趋势进行了展望 ,以推进污水生态处理系统的技术创新和在我国各地区的广泛应用 ,为全面实施污水处理与水资源综合利用相结合的污水无害化与资源化战略提供科学依据与技术支撑。

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对不同畜禽粪便在堆肥过程中各种含氮化合物的动态变化进行了研究,结合综合性腐熟度评价指标——种子发芽指数(GI),探讨了畜禽粪便堆肥过程中与氮有关的腐熟度评价指标.结果表明:随着堆肥的进行,除奶牛粪外,其它畜禽粪便的全氮(TN)含量均呈先下降而后平稳变化趋势,奶牛粪则呈先增加而后平稳变化趋势;各种畜禽粪便中,碱解性氮(HN)含量先增后降;NH4+-N含量先下降而后保持平稳;NO3--N含量则持续增加;NH4+-N/NO3--N迅速降低.堆肥腐熟度指标中,除综合性评价指标GI值外,HN/TN和NH4+-N/TN也可作为评价畜禽粪便腐熟程度的优选指标,而NO3--N/TN只能作为一般性评价指标.根据综合性评价指标GI值达到腐熟要求的标准(GI>0.50),除仔猪粪外,其它畜禽粪便在HN/TN<20.77%、NH4+-N/TN<10.06%及NO3--N/TN>0.38%时基本达到腐熟要求.