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1.
牡丹皮及种植土壤中重金属元素铅和镉的分析 总被引:2,自引:0,他引:2
测定不同产地牡丹皮及种植土壤中的重金属铅、镉含量,并分析牡丹皮与种植土壤中铅、镉含量的相关性.从安徽和山东产地采样,通过硝酸-过氧化氢-氢氟酸体系进行牡丹皮和种植土壤微波消解,用石墨炉原子吸收光谱法(GFAAS)测定牡丹皮和种植土壤中铅、镉含量.Pb元素在0-60μg/L范围内线性关系良好,回收率为102.35%,精密度RSD为1.6% ;Cd元素在0-4μg/L范围内线性关系良好,回收率为99.85%,精密度RSD为0.7%.不同产地牡丹皮均检出重金属元素铅和镉,铅含量偏低、镉含量偏高;种植土壤中的铅、镉含量比较高,大约是牡丹皮的6-7倍.该方法具有分析速度快、测定结果的精确度和精密度高等特点.种植土壤存在着重金属污染现象,为确保药材质量,保护环境、保护药材种植土壤是非常必要的. 相似文献
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火焰原子吸收光谱法测定香菇菌棒中的铜、铅、镉 总被引:2,自引:0,他引:2
用火焰原子吸收光谱法测定香菇菌棒中的铜、铅、镉含量,一次处理样品可同时测定铜、铅、镉等元素,加标回收率在92.6%-98.2%之间,方法简便、快速,结果令人满意。 相似文献
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用火焰原子吸收光谱法测定粉葛中铜的含量,石墨炉原子吸收光谱法测定粉葛中铅、镉的含量.在实验条件优化情况下,测定方法铜、铅、镉的检出限分别为:0.03mg·L-1、0.243μg·L-1和0.012μg·L-1,回收率在97.26%-105.60%之间,相对标准偏差均小于5%.实验结果表明,该方法简便、快速、灵敏.所测不同产地粉葛样品中铜、铅和镉3种重金属元素含量均在《药用植物及制剂进出口绿色行业标准》的限量指标内. 相似文献
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鸡精和味精中铅、镉含量的测定 总被引:7,自引:1,他引:6
采用原子吸收法测定了鸡精和味精中污染元素铅、镉的含量。结果表明,不同品牌的鸡精和味精所含铅、镉的量不同。该方法简便、快速、准确、实用。测定的线性范围为铅000~1000μg·mL-1,镉000~400μg·mL-1。铅和镉的精密度试验的相对标准偏差分别为315%和426%,并进行了回收实验,回收率铅在967%~1021%,镉在919%~1076%之间。 相似文献
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ICP-MS测定三种抗肿瘤中成药中铅镉汞砷含量 总被引:9,自引:0,他引:9
采用电感耦合等离子体一质谱(ICP-MS)法测定了三种抗肿瘤中成药(金克槐耳、华蟾素和复方苦参)中四种元素铅、镉、汞、砷的含量.结果显示,铅、镉、汞、砷四种元素在三种抗肿瘤中成药中的含量较低,均符合东南亚进口标准.其中金克槐耳中汞和砷含量略高于美国FAD药品与功能性食品要求标准,但仍符合其他标准.电感耦合等离子体-质谱法是测定中成药中铅、镉、汞、砷快速、准确的方法. 相似文献
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B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 2, pp. 200–205, March–April, 1995. 相似文献
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土壤中铅、砷、铬、铜和锌含量的连续快速测定 总被引:4,自引:0,他引:4
建立了土壤中铅、砷、铬、铜和锌含量的连续快速测定方法。土壤样品经微波消解,用同一份消解液,分别连续测定土壤中的铅、砷、铬、铜和锌含量,铬、铜和锌采用火焰原子吸收光谱法,铅和砷采用氢化物发生-原子荧光光谱法。采用本方法,对环境土壤标准样品ESS-1黑钙土(GSBZ50011)和ESS-3红壤(GSBZ50013)进行多次测定,检测结果与标样的推荐值吻合。经统计计算,回收率为95.2%—103.6%,精密度RSD均小于7%。本法操作简单快速,光谱测定结果已成功地用于无公害水果和蔬菜生产基地的土壤环境质量评价。 相似文献
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Frequency-selective surface (FSS) is a two-dimensional periodic structure consisting of a dielectric substrate and the metal units (or apertures) arranged periodically on it. When manufacturing the substrate, its thickness and dielectric constant suffer process tolerances. This may induce the center frequency of the FSS to shift, and consequently influence its characteristics. In this paper, a bandpass FSS structure is designed. The units are the Jerusalem crosses arranged squarely. The mode-matching technique is used for simulation. The influence of the tolerances of the substrate's thickness and dielectric constant on the center frequency is analyzed. Results show that the tolerances of thickness and dielectric constant have different influences on the center frequency of the FSS. It is necessary to ensure the process tolerance of the dielectric constant in the design and manufacturing of the substrate in order to stabilize the center frequency. 相似文献
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Stable-plasma generators, spectroscopic measuring equipment, and methods for determining the optical properties of an extremely
heated medium with a given composition have been developed. The spectral coefficients of absorption and emission of heated
air, carbon dioxide, and argon were studied. A comparison with the data of other theoretical and experimental investigations
has been performed.
Deceased.
Institute of Molecular and Atomic Physics of the Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 818–826, November–December, 1997. 相似文献
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A. I. Akimov A. N. Baranov L. V. Levshin A. M. Saletskii 《Journal of Applied Spectroscopy》1996,63(2):188-193
M. V. Lomonosov Moscow State University, Vorob'yovy Gory, Moscow, 119899, Russia. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 63, No. 2, pp. 236–241, March–April, 1996. 相似文献
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The carrier frequency offset(CFO)and impulse noise always affect the performance of underwater acoustic communication_systems.The CFO and impulse noise could be estimated by using the null subcarriers to cancel the effects of the two types of interference.The null subcarriers estimation methods include optimal separate estimation and joint estimation.The separate estimation firstly estimates the CFO value and then estimates the impulse noise value.However,the CFO and impulse noise always affect each other when either of them is estimated separately.The performance could be improved by using the joint estimation.The results of simulations and experiments have showed that these two optimization methods have good performance and the joint estimation has better performance than the separate estimation method.There is 3 dB performance gain at the BER value of 10~(-2)when using the joint estimation method.Thus these methods could improve the system robustness by using the CFO compensation and impulse noise suppression. 相似文献
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The differences of the pitch and duration of Chinese syllables between Putonghua (PTH) and Taiwan Mandarin (TM) were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that: For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM. 相似文献
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The transmission properties of one-dimensional photonic crystals containing double-negative and singlenegative materials are studied theoretically.A special kind of photonic band gap is found in this structure.This gap is invariant with scaling and insensitive to thickness fluctuation.But when changing the ratio of the thickness of two media.the width of the gap could be enlarged.The defect modes are analyzed by inducing a linear defect layer in the structure.It is found that the number of defect modes will increase when the thickness of the defect layer becomes larger. 相似文献
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JIA Duojie 《中国物理C(英文版)》2008,32(7)
It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1]. 相似文献
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M-ary and code shift keying(CSK)spread spectrum is generally applied to overcoming the spreading gain versus data rate limitation in underwater acoustic(UWA)communications.In addition,the concept of orthogonal M-ary CSK is introduced to UWA communication to gain higher rates.We propose a scheme employing dual-orthogonal-channel M-ary and CSK spread spectrum UWA communication based on Gold sequences owing large code set and good self and cross correlation.The modulation and demodulation scheme of the orthogonal M-ary CSK is derived algebraically and the factors critical to its performance are discussed.Furthermore,its bit error rate(BER)curve is evaluated via simulations and compared with the dual-channel M-ary CSK.Finally,the validity of the simulations is verified in tank experiments.1096.8 bps data rate of the proposed communication scheme is realized for 10 kbits data volume with no error.Overall through deduction,numerical simulation,and experiment,it is shown that the proposed method offers significantly improved performance. 相似文献