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41.
42.
速冻蔬菜中氯氰菊酯残留量的测量不确定度评定 总被引:2,自引:0,他引:2
依据GB/T 5009.146-2003《植物性食品中有机氯和拟除虫菊酯类农药多种残留的测定》方法,对速冻蔬菜中氯氰菊酯残留量的测量不确定度进行分析和评定。该测量过程所产生的测量不确定度主要来源于气相色谱仪引入的测量不确定度,其次是氯氰菊酯标准工作溶液引入的测量不确定度。标准溶液引入的测量不确定度则主要来源于标准溶液的稀释过程所产生的测量不确定度。 相似文献
43.
J. C. Raines J. P. Schmidt J. P. Burelbach H. K. Fauske 《Journal of Thermal Analysis and Calorimetry》2006,85(1):53-55
Hydrogen
peroxide is a very versatile oxidizing agent, and it is also environmentally
compatible considering that the products of its exothermic decomposition are
oxygen and water.When kept in a clean temperature-controlled environment,
the self-reaction (decomposition) rate is extremely low. However, it is well
known that even a small amount of contamination will dramatically increase
the reaction rate. This paper describes the use of the fast thermal activity
interpreter (FTAI) instrument to examine the chemical reactivity of commercially
available 50% hydrogen peroxide at two different temperatures (30 and 40°C)
both with and without contamination. The results show that at 30°C a small
amount of rust (330 ppm) increases the reaction rate of 50% hydrogen peroxide
by a factor of 50. When the temperature is increased to 40°C, the reaction
rate is further increased by almost a factor of four. The implication for
reactivity management is that at this contamination level most practical vessel
sizes would require emergency venting capability.
An evaluation
was then performed to determine the emergency venting requirement for the
safe transportation or storage of the contaminated hydrogen peroxide. It was
determined that for quantities of the material less than 5 gallons, conventional
breather vents would be sufficient to accommodate the gas evolved. However,
for larger quantities, a safety relief device would be needed. For example,
for a 400-gallon tote bin at 40°C the required minimum vent area is estimated
to be 4.3 in2, corresponding to a minimum vent
diameter of 2.3 inches. 相似文献
44.
45.
46.
设{Xni:1≤i≤n,n≥1}为行间独立的B值r.v.阵列,g(z)是指数为1/p的正则变化函数,r>0,{ani 1≤t≤n,n≥1}为实数阵列,本文得到了使(?)成立的条件,推广并改进了Stout及Sung等的著名结论. 相似文献
47.
This paper is about algorithms that schedule tasks to be performed in a distributed failure‐prone environment, when processors communicate by message‐passing, and when tasks are independent and of unit length. The processors work under synchrony and may fail by crashing. Failure patterns are imposed by adversaries. Linearly‐bounded adversaries may fail up to a constant fraction of the processors. Weakly‐adaptive adversaries have to select, prior to the start of an execution, a subset of processors to be failure‐prone, and then may fail only the selected processors, at arbitrary steps, in the course of the execution. Strongly adaptive adversaries have a total number of failures as the only restriction on failure patterns. The measures of complexity are work, measured as the available processor steps, and communication, measured as the number of point‐to‐point messages. A randomized algorithm is developed, that attains both ??(n log*n) expected work and ??(n log*n) expected communication, against weakly‐adaptive linearly‐bounded adversaries, in the case when the numbers of tasks and processors are both equal to n. This is in contrast with performance of algorithms against strongly‐adaptive linearly‐bounded adversaries, which has to be Ω(n log n/log log n) in terms of work. © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 2004 相似文献
48.
F-H实验仪与光栅光谱仪连用观测253.7nm谱线 总被引:1,自引:0,他引:1
通过F-H实验仪和光栅光谱仪的连用,可实时观测汞原子从6s6s1So态激发到6s6sSP1态,退激时,辐射出能量为4.9eV的光量子,其波长为253.7nm. 相似文献
50.
多自由度测试技术的发展 总被引:3,自引:1,他引:2
介绍目前较常用的多种多自由度测试技术,给出每种测试技术的测试原理和应用场合,比较各种技术的优缺点和适用范围,讨论该技术发展的方向。 相似文献