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顶空-气相色谱法测定土壤中代森锌的残留  [PDF]
周伟峰,王婷,马兴华,黄旭锋,侯坤
环境化学 , 2015,
Abstract: 研究了顶空-气相色谱法间接测定土壤中代森锌的残留.以CS2量代表代森锌残留量建立代森锌工作曲线,消除了由于CS2/代森锌的质量转换系数不确定所带来的困难.结果表明,代森锌工作曲线在0.14—2.75mg·L-1范围内呈良好的线性关系,线性方程为y=854.57x+9.2481,相关系数为0.9997.当土壤取样量为4g,定容体积8mL时,代森锌在土壤中的方法检出线为0.07mg·kg-1,相对标准偏差在5%—15%之间,平均回收率在82%—84%之间.
随机阵列码:一种高容灾易扩展的RAID存储容灾方法  [PDF]
滕鹏国,张景中,陈亮,王晓京
- , 2017, DOI: 10.15961/j.jsuese.201600492
Abstract: 中文摘要: 针对RAID存储容灾系统中数据存储的可靠性和扩展性等问题,提出一种具有较高容灾能力且易扩展的存储容灾方法,称之为随机阵列码。通过研究 GF(2)上随机矩阵列满秩的性质,并将其应用在RAID存储容灾方案中。首先,依据RAID存储系统的环境配置和容灾需求设置条带参数;其次,构建相应规模且满足特定性质的随机矩阵作为编码矩阵;最后,将原始数据等分成块,利用编码矩阵将其编码并折叠存储到不同磁盘上。当发生磁盘损毁、扇区失效等原因造成数据丢失时,可依据相应的校验矩阵及剩余的编码分块进行失效数据的高概率译码恢复,从而,实现了数据高效、可靠地容灾存储。实验验证及理论分析表明:1) GF(2)上的随机高矩阵,在随机概率 p=0.5,矩阵行列差 δ ≥15时,即具有高概率列满秩的性质;2)随机阵列码的编码参数,不再受到素数或有限域规模的限制,可灵活设置,其容灾能力也可根据容灾需求进行扩展,并可实现较多的容错模式;3)随机阵列码由于基于XOR运算,在均匀随机时与RS码、CRS码相比,具有较高的编译码速率,特别是在较大规模的编码构造中表现良好;4)随机阵列码随着规模的增长,可趋于近似MDS码,具有较高的存储空间利用率。基于随机阵列码高效,可靠,易扩展等特点,可实现一般化RAID存储容灾方案的构造,此外,也可与其他存储容灾技术结合使用,共同构建特定需求下的RAID存储容灾系统。
Abstract:To improve the reliability and scalability of data storage in redundant arrays of inexpensive disks (RAID) storage system,a new kind of storage fault-tolerance method with high fault-tolerance and flexible scalability was proposed,named random RAID.A research on the properties of random matrices in GF(2) was conducted and applied in the RAID storage fault-tolerance system.At first,the stripe parameters were set by the storage environment configuration and fault-tolerance requirement,then a random matrix was created as the generator matrix,with corresponding scale and some specific properties.Finally,the origin data was split into blocks with equal size, and encoded by the generator matrix, then folded into different disks.When there were data loss caused by disk damage or sector failures,the lost data could be recovered by the corresponding parity-check matrix and the remaining encoded blocks with high probability,enabling efficient and reliable data storage.Theoretical and experimental results show that:1) When random probability p=0.5 and the subtraction of row and column δ ≥15,the random high matrix in GF(2) could be full column rank with high probability;2)The encoding parameters of random RAID weren't constrained by the prime or scale of finite field any more.Instead,they can be set flexibly.The fault-tolerance can also be scaled with different fault-tolerance requirements, and allow more error patterns;3)When using uniform random matrix and compared with RS and CRS,the random RAID can improve the speeds of encoding and decoding greatly thanks to XOR operations,especially in large scale coding constructions;4)With the growth of the scale,the random RAID tends to approximate MDS,thus realizing highly efficient storage.Due to the properties of efficiency,reliability and scalability,the random RAID can realize the general construction of RAID storage fault-tolerance system.Moreover,it can be combined with other fault-tolerance technologies to construct
甲基化衍生-高效液相色谱法检测代森锰锌在花生中的残留量  [PDF]
马婧玮,董姝君,游文宇,张敬平,钮伟民,潘灿平
农药学学报 , 2007,
Abstract: 建立了简单、快速测定花生中杀菌剂代森锰锌的残留检测方法。花生样品用l-半胱氨酸盐酸盐和edta-2na的混合溶液振荡提取,在ph=6.5~8.5时,用0.05mol/l的碘甲烷与三氯甲烷-正己烷(3∶1,体积比)的混合溶液进行甲基化反应。有机层经浓缩后,用乙腈定容,采用高效液相色谱仪在272nm处进行检测。色谱柱为agilenttc-c18,流动相为乙腈-水(50∶50,体积比),以1.0ml/min的流速等梯度洗脱。结果表明,代森锰锌的添加浓度在0.05~2.00mg/kg范围内,平均回收率为76.1%~86.2%,变异系数分别为0.7%~10.2%,均在农药残留测定所允许的范围内。该方法的最低检出限(lod)为0.02mg/kg,最低检测浓度(loq)为0.05mg/kg。
月壤及模拟月壤微观结构的研究  [PDF]
李丽华,唐辉明,刘数华
岩土力学 , 2012,
Abstract: 为了对比研究月壤与模拟月壤的微观结构,介绍了月壤的形成作用过程和5种基本颗粒类型;通过真实月壤照片,对月壤微观结构进行了分析;利用火山灰为模拟月壤主体材料,对其成分进行了检测;对模拟月壤的火山灰颗粒进行了显微图像分析试验。结果表明,月壤存在胶结物微观颗粒,胶结物颗粒具有分支的组织形态和封闭的气泡,并且有金属铁珠存在;火山灰所含的主要成分及含量与月壤相似,经过粉碎的火山灰试样棱角较为明显,其纵横比峰值略小,稍显长条状,但与月壤比较相近,而复杂度因子则略有欠缺,说明颗粒还不够粗糙和多棱
变余容Nobel-Abel方程  [PDF]
陈东雷
兵工学报 , 1989,
Abstract: ?本文指出了目前内弹道中普遍使用的定余容Nobel-Abel状态方程的局限性,讨论了将余容作为密度或温度函数,得到了变余容的Nobel-Abel方程。最后,本文还给出了各种不同火药在燃烧以后其余容随密度或温度变化的函数关系。
活动断裂带的壤中气汞量测量研究  [PDF]
地质论评 , 1998,
Abstract: 在覆盖区应用壤中气汞量测量研究活动断裂是一种新方法,它不仅能较准确地确定活动断裂的位置,还可以确定其产状,规模,活动性及相对强度,甚至可以作为确定断裂力学性质的参考,本文简棕了断裂带壤中气汞量测量的基本原理,并以长江三峡,长春,吉林等地利用该种方法研究活动断裂的成果为例,说明该项研究的效果及应用前景。
非简谐振动和形变对ZnSe类石墨烯德拜温度热容量以及极性的影响
Influence of the anharmonic vibration and deformation on the Debye temperature heat capacity and polarity of ZnSe graphene-like
 [PDF]

周恩民,程正富,郑瑞伦,查小婷,李召红
- , 2018,
Abstract: 应用哈里森(Harrison)键联轨道法和固体物理理论和方法,考虑到原子的高阶非简谐振动,计算了ZnSe类石墨烯化合物的键和键的极性、简谐系数和非简谐系数,得到它的德拜温度和定容热容量随温度变化的解析式以及形变引起的极性参量的改变量,探讨了形变对ZnSe类石墨烯极性的影响,并讨论了原子非简谐振动对化合物热力学性质的影响,结果表明:在300K到1600K温度区间内,简谐近似下,ZnSe的德拜温度为常量,热容量随着温度的升高呈非线性增大,其中温度较低时变化较快,温度较高时变化较慢并随着温度的升高而趋于常量。考虑到非简谐项后,德拜温度随着温度升高而增大,几乎为正比关系,而热容量的值比简谐近似的值有所减小,与第一非简谐项的影响相比,第二非简谐项的影响很小。形变对ZnSe类石墨烯的极性有重要的影响,在它的几种形变中,剪切形变对键的极性的影响最大,而键长形变对键的极性的影响最小。温度愈高,非简谐效应愈显著。
Abstract:This work uses Harrison bonding orbital method and solid physical theory to calculate the polarities of and bonds, harmonic and anharmonic coefficients of ZnSe graphene-like compound on the consideration of high order anharmonic vibration of the atom. The Debye temperature, temperature-dependence analytical formula of heat capacity at constant volume, and change of polarity parameter caused by the deformation are therefore obtained, and the effect of deformation on the polarity of ZnSe class graphene and the influence of atomic anharmonic vibration on thermodynamic properties of compounds are discussed. The result shows that between 300k to 1600k temperatures, Debye temperature is constant under the harmonic approximation, heat capacity increases with the increase of temperature in a nonlinear way, it changed fast at low temperature, then changed slowly at high temperature, finally became constant with the increase of temperature. When non-simple harmonic term is considered, Debye temperature increases with the increase of temperature in a near proportional relation, the value of heat capacity reduces compared with that under the harmonic approximation. The research discloses that the second non-simple harmonic term has smaller influence compared with the first non-simple harmonic term. Therefore, the deformations have an important impact on polarity of ZnSe class graphene. Shear deformation has the greatest influence on polarity of bond, while bond length deformation has the smallest influence on polarity of bond. Anharmonic effect presents obviously with the increase of temperature. (The higher is temperature, the more obvious anharmonic effect is presented.)
“侨易”过程中的“主体认同”与“移简”规则产生――以台湾华语情歌中的张爱玲形象为例
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 [PDF]

萧凤娴
- , 2018,
Abstract: “移简”现象,是“侨易”过程中的“主体认同”,因移动产生变化(“移变”),导致对母文化常态的影响焦虑(“移常”)。“侨易主体”因此必须再接受、化约异文化,产生简洁原则(“移简”),才能安身立命、发展己志。“移简”后的简洁原则,会再与异文化“移交”,最后形成“侨易学”中的“移易现象”。透过台湾华语情歌歌词中的“张爱玲”形象,可以看出华语流行音乐工业如何“移简”张爱玲形象,反映大众对自我身份的看法,借以刺激消费、产生利润,并引导社会大众的身份认同。
s-波/铁磁/p-波超导结中的约瑟夫森电流:最低反常简谐项的贡献
Josephson current in s-wave superconductor/ ferromagnet/p-wave superconductor junctions: the lowest unusual harmonic contribution
 [PDF]

鲍志勇,金彪
- , 2016, DOI: 10.7523/j.issn.2095-6134.2016.03.009
Abstract: 摘要 用Matsubara格林函数方法研究s波超导/铁磁/p波超导结构的约瑟夫森效应.研究中考虑了p波超导中的3种配对形式.发现约瑟夫森电流的最低阶项是cosφ,讨论这个反常项(cosφ)随铁磁强度和铁磁宽度的变化.在这个系统中发现0-π转变,考虑了该系统在自旋电子学中的应用.
《海森伯传》译者引言  [PDF]
戈革
物理 , 2004,
Abstract: ?《海森伯传》译者引言
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