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Search Results: 1 - 10 of 117355 matches for " 崔伟成 "
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湖北清江现代植物叶片正构烷烃和烯烃的季节性变化
,黄俊华,谢树
科学通报 , 2008,
Abstract: 利用气相色谱和气相色谱-质谱联用仪分析了湖北清江岩溶地区5种植物叶片类脂物的季节性变化特征.随季节的变化,同一植物叶片正构烷烃的碳数分布范围和主峰碳数不变,但正构烷烃的碳优势指数(CPI)从5月到11月逐渐降低,这种变化可能与植物叶片在枯萎过程中类脂物的变化有关,活体叶片与相应植物落叶的比较也证实了这点.这反映了在第四纪沉积物中正构烷烃CPI可能与腐殖化过程有关而可以指示与之相关的气候环境条件.不同植物的正构烷烃含量差别较大,对沉积物的输入贡献不一.正构烯烃含量和种类明显随季节变化,可能与环境温度变化有关.8月份温度最高,正构烯烃的种类最少.
新型材料六铝酸盐LaMAl11O19-δ的合成及催化性能
赵丽娜,,王庆
化工进展 , 2010,
Abstract: 采用高温分解法,通过过渡金属M(M=Fe、Co、Ni、Mn和Cu)的晶格取代,制备了一系列新型六铝酸盐复合氧化物催化剂,并通过XRD、XPS、TPR、SAA、TGA等测试手段对催化剂的结构和性质进行了表征,并考察了其甲烷部分氧化制合成气反应的催化活性。实验结果表明,相同M取代系列六铝酸盐中过渡金属活性顺序均为Cu
基于径向基神经网络的电火工品安全电流预测方法
,刘林密,孟凡磊
含能材料 , 2012, DOI: 10.3969/j.issn.1006-9941.2012.03.020
Abstract: 为了预测单发电火工品的安全电流,通过瞬态脉冲试验得到电火工品的电阻和集总热散失系数,结合升降法得到的安全电流对集总热散失系数进行补偿,采用径向基(RBF)神经网络预测电火工品的安全电流。结果表明:安全电流预测值与发火验证试验结果基本一致,为264mA;预测值高的电火工品在相同的恒流脉冲下发火的概率小;预测均值与升降法得到的整批产品的安全电流相等。
地西泮与乙醇协同作用机制的荧光光谱分析
胜峰,万敬,
- , 2018,
Abstract: 文章导
LCD、k-means与ICA相结合的滚动轴承故障诊断方法
Fault Diagnosis of Rolling Bearing using LCD, k-means and ICA

孟凡磊,,李伟,刘林密
- , 2017,
Abstract: 为了准确地进行滚动轴承故障诊断,针对故障振动信号的低信噪比特征,提出了局部特征尺度分解、k均值聚类分析和独立分量分析相结合的故障诊断方法。首先,应用局部特征尺度分解对振动信号进行分解,得到若干个内禀尺度分量;然后,依据分量与原始信号的互相关系数及峭度值,应用k均值聚类方法选取有效的分量组成新的观测信号;最后,对观测信号进行独立分量分析处理,实现信噪分离,依据峭度值选取信号分量,对信号应用希尔伯特包络谱技术实现故障诊断。通过轴承内圈故障数据分析,验证了方法的有效性。
The rolling bearing fault vibration signals have low signal-to-noise ratio. Aiming at diagnosing the fault of rolling bearing accurately, a method based on local characteristic-scale decomposition(LCD), k-means cluster analysis and independent component analysis(ICA) was proposed. Firstly, the vibration signal was decomposed into some intrinsic mode components (ISC) by LCD. Then the correlation coefficients of every ISC and the original signal and the kurtosis value of every ISC were calculated, the efficient components were selected by means of k-means cluster analysis. The efficient components were processed by ICA to separate the signal from the noise, and the signal components were selected according to the kurtosis values. Finally, the Hilbert envelope aptitude envelope spectrum was used for fault diagnosis. The analysis of the bearing fault data shows that the method can realize weak signal detection and fault diagnosis effectively
氟菌唑在人参和土壤中的残留动态和残留限量研究
丽丽,冯志,高洁,许允,王春
华南农业大学学报 , 2014, DOI: 10.7671/j.issn.1001-411X.2014.01.013
Abstract: 【目的】对人参中氟菌唑残留动态进行研究,使其在人参上的使用合理化.【方法】通过田间试验和气质联用方法检测了质量分数为30%氟菌唑WP施药后0、7、14、21、28和74d(收获期)在人参和土壤中的消解动态及最终残留量.【结果和结论】施药剂量为1000g·hm-2,施药1次时,氟菌唑在人参和土壤中的原始沉积量分别为0.54和0.25mg·kg-1;半衰期分别为19.9和25.4d;收获时鲜人参根中氟菌唑最终残留量为0.04mg·kg-1、干人参的残留量为0.14mg·kg-1;综合多方面因素,建议我国鲜人参中氟菌唑的最大残留限量值(MRL)暂定为0.05mg·kg-1、干人参暂定为0.20mg·kg-1;施药量不高于1000g·hm-2,一个生长季节施药1次.安全间隔期无法确定.
抛物型SPDE中假设检验的中偏差原理
Moderate Deviations of Hypothesis Testing in Stochastic Partial Differential Equations
 [PDF]


Pure Mathematics (PM) , 2015, DOI: 10.12677/PM.2015.52005
Abstract:
本论文的目的是研究由可加分布朗运动驱动的随机偏微分方程中漂移系数的假设检验问题,其中Hurst系数为H∈[?21,1)。并且我们利用对数似然比的中偏差原理,在维数N固定,时间T趋于无穷的情况下,给出了未知参数的拒绝域和两类错误的衰减速度。最后我们将结果应用在几个例子当中。
In this paper, we focus our attention on the hypothesis testing problem for the drift coefficient in the diagonalizable stochastic evolution equation driven by additive fractional Brownian motion with Hurst parameter H∈[?21,1);. And when the dimension N is fixed and observation time T tends to infinity, with the help of moderate deviations for the log-likelihood ratio process, we give the negative regions and obtain the decay rates of the error probabilities. Moreover, we also apply our results to some examples.
Polarization-dependent Lumped Amplification in Birefringent Fibers
双折射光纤中偏振相关的集总放大研究

(,
,徐文成,梁湛强,罗爱平,

光子学报 , 2007,
Abstract: The effects of polarization-dependent lumped amplification schemes on nonlinear pulse propagation are studied.Polarization-dependent lumped amplification with nonlinear gain is suggested to use for suppressing the splitting-mergence soliton interactions and linear dispersive waves induced by random birefringence.Numerical calculation proves that the differential group delay between two components after the first amplifier becomes much smaller in polarization-dependent lumped amplification scheme with nonlinear gain,which means that the periodical pulse splitting and mergence interactions are suppressed efficiently.Moreover,polarization dependent gain of the following amplifier with nonlinear gain will promote the appearance of whether breath oscillation behavior of two components or full trapping of them in the transmission.
液相色谱-串联质谱法研究腈菌唑在人参根、茎、叶和土壤中的残留动态
王燕,王春,高洁,丽丽,许允
中国中药杂志 , 2014,
Abstract: 建立了人参根、茎、叶及土壤中腈菌唑的液相色谱-串联质谱检测方法,并研究了25%腈菌唑水分散粒剂在人参根、茎、叶和土壤中的消解动态及最终残留量。样品经丙酮提取,N-丙基乙二胺(PSA)固相萃取柱净化后,经KromasilEternity-5-C18(2.1mm×150mm,5μm)色谱柱分离,以乙腈和0.1%甲酸水溶液为流动相进行洗脱,采用质谱正离子扫描,多反应监测模式进行定量分析,外标法定量。在0.01~0.20mg·kg-1添加范围内,回收率为80.9%~90.7%,相对标准偏差为5.54%~9.29%,定量限为0.005mg·kg-1。该方法精密度高,重复性好,检出限低,能满足生产上对腈菌唑检测分析的要求。施药剂量为1152g·hm-2(以有效成分含量计)时,腈菌唑在人参根、茎、叶和土壤中的降解半衰期为6.25~9.94d。施药剂量为576~1152g·hm-2时,腈菌唑在人参根、茎、叶和土壤中的最终残留量分别为未检出~0.0601mg·kg-1,未检出~0.0817mg·kg-1,0.0060~0.1022mg·kg-1和未检出~0.0376mg·kg-1。建议我国腈菌唑在干人参中的最大残留限量值分别为0.10mg·kg-1,安全间隔期为35d。
尿中粪卟啉的正常值及其对铅中毒诊断意义的探讨
, 田庆, 马桂荣, 王瑞, 德全
中国公共卫生 , 1985,
Abstract: ?铅对血红素合成的抑制作用可使尿中粪卟啉(cp-u)含量增加,其增加的程度与工人接触铅的浓度和时间有关。许多人对cp-u早期诊断铅中毒方面的价值进行了研究,认为对铅中毒的筛选或早期诊断具有一定意义。
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