56 resultados para 853
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试验以洱海流域的背角无齿蚌为研究对象,确定常用鱼药:漂白粉、氯杀宁对湖泊大型底柄动物背角无齿蚌的毒性影响.试验得出漂白粉作用下,背角无齿蚌24 h、48 h、72 h、96 h、120 h、144 h、168 h的半致死率;氯杀宁作用下,背角无齿蚌24 h、48 h、72 h、96 h的半致死率;漂白粉有效氯安全浓度95.25~108.86 mg/L;氯杀宁有效氯安全浓度3.32~3.55 mg/L.通过显微镜观察,漂白粉和氯杀宁的主要作用部位为背角无齿蚌的呼吸系统,在其鳃上可见明显病变.
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用血球凝集和血清吸收试验的方法,对若干个鲤鱼品种及鲤鱼人工雌核发育系的红血球中的某些同种异型抗原纯合性进行了初步研究。①以抗雌核发育红鲤抗血清(abs/R)为试剂,三个雌核发育系(R_(8305),R_(8413),RMGF_1)的RBC反应值分别为1521—2360,1521—2028,853—1521,普通红鲤、镜鲤、白鲢的反应值在80—782。②abs/8305与abs/8413经靶细胞相互吸收后的残留活性显著降低(均为320),而以自鲢RBC吸收后抗血清活性不变。作者认为这部分抗原在鲤鱼种以下的品
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Seasonal population dynamics of the digenean Phyllodistomum pawlovskii in the urinary bladder of the bullhead catfish, Pseudobagrus fulvidraco, were investigated in Liangzi Lake in the flood plain of the Yangtze River in China from February 2001 to July 2002. The overall prevalence of the parasite was high, 41.5% (n = 1,476), while the mean abundance was relatively low, 1.24 +/- 2.11. The parasite exhibited evident seasonality in changes of prevalence and abundance. In brief, prevalence and abundance were very low in midwinter (January), but increased and remained relatively high in other seasons and months. The distribution pattern of this parasite in the fish was overdispersed, with a variance to mean ratio > 1, but its frequency distribution could not be described by the negative binomial model. There were positive correlations between the number of the parasites per fish and the age and length of the fish; a peaked age-parasite abundance curve was not detected in the parasite-host association. It is suggested that the parasite P. pawlovskii has little effect on the population structure of the bullhead catfish.
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在随机Oracle模型的基础上, 提出一种基于单向陷门置换(trapdoor permutations, TDPs)的、可并行的、长消息签密方案——PLSC (parallel long-message signcryption). 该方法采用“整体搅乱, 局部加密(scramble all, and encrypt small)”的思想, 用一个伪随机数对要传送的消息和用户的身份(ID)进行“搅乱(scrambling operation)”, 然后对两个固定长度的小片段(并行地)进行单向陷门置换(TDP)操作. 这种设计使得整个方案可直接高效地处理任意长度的消息, 既可避免循环调用单向陷门置换(如CBC模式)所造成的计算资源的极度消耗, 也可避免由“对称加密方案”与“签密方案”进行“黑盒混合(black-box hybrid)”所造成的填充(padding)冗余. 不仅可以显著地节约消息带宽, 而且可以显著地提高整体效率. 具体地说, 该方法对任何长度的消息进行签密, 仅需进行一次接收方的TDP运算(相当于加密), 以及一次发送方的TDP运算(相当于签名), 从而最大限度地降低了TDP运算的次数, 提高了整体的运算效率. 因为, 对于公钥加密算法来说, 运算量主要集中在TDP运算上, TDP运算是整个算法的瓶颈所在. 另一方面, 由于避免了填充上的冗余, 新方案的效率也高于标准的“黑盒混合”方案.重要的是, 新方案能够达到选择密文攻击下的紧致的语义安全性(IND- CCA2)、密文完整性(INT-CTXT)以及不可否认性(non-repudiation). 而且所有这些安全要求都可以在多用户(multi-user)、内部安全(insider-security)的环境下得以实现. 另外, 尽管新方案主要针对长消息的签密, 但它也可应用于某些不能进行大块数据处理的环境(智能卡或其他只有少量内存的环境). 也就是说, 对于这些小内存设备来说, 仍然可以用该方案来实现长消息的签密处理.
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CFCs问题引起了广泛的研究。本文概述了CFCs问题及新开发的替代物,列表给出了其用RKS和RP方程计算的相关系数,CFCs混合物的计算,最大的障碍是相互作用系数K_(?)的取得,文中给出了具体的计算方法,也提供了最新的可考数据,还提出了一种尝试性的方法。这些对热力数据仍十分有限的CFCs新工质的模拟计算具有现实价值。
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Microscopic characteristics of the GaAs(100) surface treated with P2S5/NH4OH solution has been investigated by using Auger-electron spectroscopy (AES) and x-ray photoemission spectroscopy (XPS). AES reveals that only phosphorus and sulfur, but not oxygen, are contained in the interface between passivation film and GaAs substrate. Using XPS it is found that both Ga2O3 and As2O3 are removed from the GaAs surface by the P2S5/NH4OH treatment; instead, gallium sulfide and arsenic sulfide are formed. The passivation film results in a reduction of the density of states of the surface electrons and an improvement of the electronic and optical properties of the GaAs surface.
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The 3-section SG-DBR tunable laser is fabricated using an ion implantation quantum-well intermixing process. The over 30nm discontinuous tuning range is achieved with the SMRS greater than 30dB.
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Ni/SiO2 interface were irradiated at room temperature with 308 MeV Xe ions to 1×1012,5×1012 Xe/cm2 and 853 MeV Pb ions to 5×1011 Pb/cm2,respectively.These samples were analyzed using Rutherford Backscattering Spectrometry(RBS) and X-ray diffraction spectroscopy(XRD),from which the intermixing and phase change were investigated.The obtained results show that both Xe-and Pb-ions could induce diffusion of Ni atoms to SiO2 substrates and result in intermixing of Ni with SiO2.Furthermore,1.0×1012 Xe/cm2 irradiat...中文摘要:在室温下用308 MeV的Xe离子和853 MeV的Pb离子辐照Ni/SiO2样品,用卢瑟福背散射和X射线衍射技术对样品进行了分析。通过分析Ni/SiO2样品中元素成分分布和结构随离子辐照剂量和电子能损的变化,探索了离子辐照在Ni/SiO2样品中引起的界面原子混合与结构相变现象。实验结果显示,Xe和Pb离子辐照均能引起明显的Ni原子向SiO2基体的扩散并导致界面附近Ni,Si和O原子的混合。实验观测到低剂量Xe离子辐照可产生NiSi2相,而高剂量Xe离子辐照则导致了Ni3Si和NiO相的形成。根据热峰模型,Ni原子的扩散和新相的形成可能由沿离子入射路径强电子激发引起的瞬间热峰过程驱动。