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1.
Abolhassani,M.D.一:Hejazi,M.;Ah- madian,A.;and Amjadi,A.:Comparison of optieal deteetion system,PVDF deteetion system,and PVDF needle hydroPhone for oPtoacoustie tomograPh扒593 Ahmadian,人.see Abolhassani,M,D.,593 All劝 adi,A.see Abolhassani,M.D.,593 Bai,Ming see Zhang,Douguo,107 Bao,Huanmin see丫V么ng,Yanyong,4; W么ng,Yanyong,6;Jia,Doxlgfang,311 Bao,N.K.see Chen,Zhongyu,319 Bi,Jinzi see Yu,Ting,92 Bian,Jing see Xie,Hongyun,156 Bu,Ydng see …  相似文献   

2.
An,Geng see Liang,Gongying,59 B乙,Peng一;and Liu,Junhua:Mixture gas component eoneentration analysis based on supPort veetor maehine and infrared spee- trum,243 Bai,XiangZhong see Chen,Mingyang,63 Bi,Guojiong see Zhang,Shenjin,658 Bi,Jin活1 s  相似文献   

3.
ICP—AES法测定锌及其化合物中的杂质元素   总被引:3,自引:0,他引:3  
采用样品溶解后直接测定及氢氧化钇共沉淀将锌与被测杂质元素分离后测定相结合,研究了锌及其化合物中Ag,Co,Al,Ni,Fe,Cu,Cd,Cr,Mn,In,As,Pb,Sn,Sb,Bi等15个杂质元素的ICP-AES测定方法,相对标准偏差1.6-8.1%。  相似文献   

4.
ICP-AES法同时测定茶叶中的锌、铁、锰、铜、镍、镁   总被引:6,自引:0,他引:6  
研究了用硝酸+硫酸+高氯酸消解样品,用ICP-AES法同时测定茶叶中锌,铁,锰,铜,镍,镁的新方法,在选定的最佳条件下,测锌,铁,锰,铜,镍,镁的检出限分别为4.2,7.8,0.4,7.3,7.6,4.8ng.mL^-1,回收率为94.7%-104.2%,RSD为0.3%-4.7%,该法准确,快速,简便,适用于茶叶样品的测定,结果令人满意。  相似文献   

5.
采用可见-近红外高光谱成像技术结合化学计量学方法检测灵武长枣维生素C(VC)含量,探究一种全新的水果内部成分的快速无损检测方法。采用高效液相色谱法(HPLC)测得长枣的VC含量化学值,可见-近红外高光谱成像系统采集164个灵武长枣400~1 000 nm的高光谱图像,利用ENVI4.8软件提取图像的感兴趣区域(region of interest,ROI),计算其平均光谱,获得光谱值,将化学值与光谱值通过The UnsecramblerX 10.4软件建立模型。利用蒙特卡洛交叉验证法剔除异常值,采用光谱理化值共生距离法(sample set partitioning based on joint x-y distance,SPXY)进行样本划分以提高模型的预测性能;对光谱采用移动平滑(moving average)、中值滤波(median filter)、归一化(normalize)、基线校准(baseline)、多元散射校正(multiple scattering correction,MSC)、去趋势(detrending)和标准正态变量变换(standard normal variate,SNV)等7种方法进行预处理;为进一步减少数据量,降低维度,提高运算速度,使用竞争性自适应加权算法(competitive adaptive reweighted sampling,CARS)、无信息变量消除算法(uninformative variable elimination ,UVE)和连续投影算法(successive projections algorithm,SPA)提取特征波长,以期实现以少数波段代替全波段;将全波段光谱(full spectrum,FS)以及CARS, UVE和SPA三种方法提取的特征波长分别建立偏最小二乘(partial least squares wavelength regression,PLSR)和支持向量机(support vector machine,SVM)模型,从而确定最优的建模模型。利用蒙特卡洛交叉验证法共剔除7个异常样本,采用SPXY法将剔除异常样本后的157个数据区分为校正集和预测集,校正集中样本个数为117,预测集中样本个数为40。将未经光谱预处理的建模结果与分别经过七种光谱预处理的建模结果相比,选择未经光谱预处理的数据进行后续分析;将未经光谱预处理的光谱值采用CARS,UVE,SPA方法进行提取特征波长,CARS共优选出406,415,487,631,636,655,660,665,670,684,689,694,723,732,747和881 nm下的光谱变量16个,利用CARS提取出的特征波长占总波长的12.8%;UVE共优选出406,415,627,631,636,651,655,660,665,670,675,679,684,689,694,699,703,708,742,747,751,756,761,766,771,775,780,785,790,795,919和924 nm下的32个特征波长,利用UVE提取出的特征波长占总波长的25.6%;SPA共优选出401,665,684 nm三个特征波长,利用SPA提取出的特征波长占总波长的2.4%。将全波段光谱与提取出的特征波长建立PLSR模型和SVM模型,对比模型结果显示UVE-SVM模型最优,其R2c为0.847 1,R2p为0.714 9,说明UVE有效地对光谱进行降维,简化了数据处理过程。本研究对高光谱成像技术在水果领域的应用进行了有益探索,探究了一种全新的灵武长枣VC含量的无损检测方法,相应建立的可见-近红外高光谱模型为其他水果成分的快速检测提供了理论基础。  相似文献   

6.
非碳纳米管研究的新进展   总被引:4,自引:0,他引:4  
张立德  张玉刚 《物理》2005,34(3):191-198
文章系统地论述了非碳纳米管的制备,较详尽地介绍了多种非碳纳米管制备最新的进展,包括硫化物、氮化物、氧化物等等,特别重点地总结了非碳纳米管前沿材料,例如WS2,Bi2S,,ZnS,GaN,BN,AlN,InP,Eu2O3,,V2O3等.最后对非碳纳米管的研究趋势作了展望.  相似文献   

7.
循环流化床热电气三联产装置研究   总被引:14,自引:0,他引:14  
循环流化床热电气三联产装置研究岑可法,方梦祥,骆仲泱,李绚天,陈飞,王勤辉,陈冠益,倪明江(浙江大学热能工程研究所杭州310027)关键词循环流化床,气化,煤气蒸汽联产1前言在近几年来,我国能源仍主要以煤炭为主,而目前煤炭的绝大部分作为燃料直接燃用,...  相似文献   

8.
元素在探针表面上的原子化机理研究   总被引:3,自引:0,他引:3  
探针原子人经法是一种新技术,本文系统地总结了用探针原子化法研究Au(1B),Sr(ⅡA),Cd(ⅡB),Al(ⅢA),La,Sm,Fu(ⅢB),Ge,Sn,Pb(ⅣA),Sb,Bi(ⅤA),V(ⅤB),Cr,Mo(ⅥB),Mn(ⅦB),Fe,Co,Ni,Pt(Ⅷ)等20个元素的原子化机理了起源于卤化物分解的元素有Au与Pt,起源于氧化物分解的元素有Cd,Al,La,Sm,Eu,Ge,Mn与Fe。  相似文献   

9.
中药方剂煎煮液中ICP—AES法同时测定16个元素   总被引:5,自引:0,他引:5  
本文提出了用硝酸-过氧化氢对中药方剂煎煮液进行处理,ICP-AES法对煎煮液中Li,Na,Be,Ca,Sr,Ba,Mg,Cu,Co,Ni,Zn,Mn,Cd,Fe,Cr,V16个元素进行同时测定的方法,该方法简单,快速,准确度高,所测元素的加标回收率均在85~103%之间,样品分析结果满意。  相似文献   

10.
半导体激光牙科治疗仪   总被引:2,自引:0,他引:2  
采用GaAlAs激光二极管作为激光源,电子定时,功率实时监测,LED红光指示,硬光纤偶合输出,工作波长830nm,输出功率130mW,属于低功率激光,主要产生刺激调理作用,消炎止痛,抗感染,改善血液循环,增强机体免疫功能  相似文献   

11.
We review the present status of the Lake Baikal neutrino experiment and present selected physics results obtained during the consecutive stages of the stepwise upgrade of the detector: from NT-36 to NT-96. The results cover atmospheric muons, neutrino events, neutrinos of very high energy, searches for neutrino events from WIMP annihilation, searches for magnetic monopoles, and environmental studies. We also describe an air Cherenkov array developed for studying the angular resolution of NT-200. From Yadernaya Fizika, Vol. 63, No. 6, 2000, pp. 1027–1036. Original English Text Copyright ? 2000 by Balkanov, Belolaptikov, Bezrukov, Budnev, Chensky, Danilchenko, Dzhilkibaev, Domogatsky, Doroshenko, Fialkovsky, Gaponenko, Garus, Gress, Kiss, Klimov, Klimushin, Koshechkin, Kuznetzov, Kulepov, Kuzmichev, Lovzov, Laudenskaite, Lubsandorzhiev, Milenin, Mirgazov, Moseiko, Netikov, Osipova, Panfilov, Parfenov, Pavlov, Pliskovsky, Pokhil, Popova, Rozanov, Sokalski, Spiering, Streicher, Tarashansky, Toht, Thon, Vasiliev, Wischnewski, Yashin. This article was submitted by the authors in English.  相似文献   

12.
Elemental analysis of fertilizer using laser induced breakdown spectroscopy   总被引:1,自引:0,他引:1  
In recent years, the use of fertilizers has increased to achieve high growth rate of agriculture products. With this increase the chemical impact of agricultural activities on the environment has also been enhanced. In order to keep the environment healthy, and clean, it is necessary to identify contaminants and characterize the sources of contamination. In this study, a comprehensive chemical characterization of a DAP fertilizer has been carried out using laser induced breakdown spectroscopy. Phosphorous, manganese, magnesium, iron, titanium, molybdenum, nickel, cobalt, aluminum, chromium, lead, and uranium traces are detected. Relative abundances of Phosphorous, manganese, magnesium, molybdenum, iron, titanium, nickel, vanadium, calcium, cobalt, cadmium, tin are 26.64, 17.75, 13 97, 8.25, 7.97, 7.11, 5.07, 3.15, 2.94, 1.94, 1,55, 1.73 percent, respectively, whereas relative abundances of sulfur, aluminum, chromium, lead, and uranium are less than 1% and their sum is 1.93% of the total sample.  相似文献   

13.
《Physics of Atomic Nuclei》2003,66(3):503-508
We review the present status of the Baikal neutrino experiment. The structure and parameters of the neutrino telescope NT-200, which was put into operation in April 1998, are described. Selected methodological results are presented. Physics results cover separating up-going muons from atmospheric neutrinos, searches for neutrino events from WIMP annihilation, searches for magnetic monopoles, and high-energy neutrinos. From Yadernaya Fizika, Vol. 66, No. 3, 2003, pp. 530–535. Original English Text Copyright ? 2003 by Balkanov, Belolaptikov, Bezrukov, Budnev, Chensky, Danilchenko, Dzhilkibaev, Domogatsky, Fialkovsky, Gaponenko, O. Gress, T. Gress, Il'yasov, Klabukov, Klimov, Klimushin, Koshechkin, Konischev, Kulepov, Kuzmichev, Kuznetsov, Lubsandorzhiev, Micheev, Milenin, Mirgazov, Moseiko, Osipova, Panfilov, Pan'kov Parfenov, Pavlov, Pliskovsky, Pokhil, Poleshuk, Popova, Prosin, Rosanov, Rubzov, Semenei, Spiering, Streicher, Tarashansky, Vasiliev, Wischnewski, Yashin, Zhukov. This article was submitted by the authors in English.  相似文献   

14.
《Physics of Atomic Nuclei》2004,67(11):2002-2010
The proposed Majorana double-beta decay experiment is based on an array of segmented intrinsic Ge detectors with a total mass of 500 kg of Ge isotopically enriched to 86% in 76Ge. A discussion is given of background reduction by material selection, detector segmentation, pulse shape analysis, and electroformation of copper parts and granularity. Predictions of the experimental sensitivity are given. For an experimental running time of 10 years over the construction and operation oft he Majorana setup, a sensitivity of T 1/2 ∼4×1027 yr is predicted. This corresponds to 〈mν〉∼0.003−0.004 eV according to recent QRPA and RQRPA matrix element calculations. From Yadernaya Fizika, Vol. 67, No. 11, 2004, pp. 2025–2032. Original English Text Copyright ? 2004 by Aalseth, Anderson, Arthur, Avignone III, Baktash, Ball, Barabash, Brodzinski, Brudanin, Bugg, Champagne, Chan, Cianciolo, Collar, Creswick, Doe, Dunham, Easterday, Efremenko, Egorov, Ejiri, Elliott, Ely, Fallon, Farach, Gaitskell, Gehman, Grzywacz, Hazma, Hime, Hossbach, Jordan, Kazkaz, Kephart, King III, Kochetov, Konovalov, Kouzes, Lesko, Macchiavelli, Miley, Mills, Nomachi, Palms, Pitts, Poon, Radford, Reeves, Robertson, Rohm, Rykaczewski, Saborov, Sandukovsky, Shawley, Stekhanov, Tornow, van de Water, Vetter, Warner, Webb, Wilkerson, Wouters, Young, Yumatov. This article was submitted by the authors in English. The authors represent the Majorana Collaboration  相似文献   

15.
Vacuum arc ion charge-state spectra have been measured for a wide range of metallic cathode materials. The charge-state distributions were measured using a time-of-flight diagnostic to monitor the energetic ion beam produced by a metal vapor vacuum arc ion source. Data were obtained for 48 metallic cathode elements: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er Yb, Hf, Ta, W, Ir, Pt, Au Pb, Bi, Th, and U. The arc was operated in a pulsed mode with pulse length 0.25 ms: arc current was 100 A throughout. The measured distributions are cataloged and compared with earlier results. Some observations about the performance of the various elements as suitable vacuum arc cathode materials are also presented  相似文献   

16.
Abstract

A microwave-assisted digestion procedure has been developed for the treatment of silicone oil samples. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentration level of 40 trace element impurities, like Li, Na, Mg, Al, P, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Sr, Rb, Zr, Nb, Mo, Ag, Cd, Sn, Sb, Ba, La, Ce, Nd, Hf, W, Au, Pb, Hg, Th, Bi and U in these samples, having obtained average relative standard deviation values of 9.6%. The methodology developed has been tested by recovery studies on different natural samples spiked with known amounts of Mg, Cr, Mn, Fe, Zn and Pb at concentration levels of 10, 0.5, 5, 5, 10 and 1 μg g?1 and recovery percentage values varies from 97 to 105 %.  相似文献   

17.
ICP-AES法测定玉米秸秆中的微量元素含量   总被引:11,自引:4,他引:11  
采用高压硝化罐处理样品,以ICP-AES法测定了我国山西、北京、新疆、山东、内蒙、甘肃、陕西、吉林、云南、江苏10个不同省区不同品种玉米秸秆中Zn,Mg,Mn,Sr,Fe,Co,Ni和Se八种微量元素的含量。实验确定加入5 mL硝酸、3 mL高氯酸以及3 mL氢氟酸,将硝化罐置于130 ℃油浴中4 h,即可将样品完全消解。此方法测定各地区玉米秸秆中Zn的回收率在96.5%~103.8%之间,Mg的回收率在98.0%~102.5%之间,Mn的回收率在95.7%~104.1%之间,Sr的回收率在97.1%~103.2%之间,Fe的回收率在95.1%~101.3%之间,Co的回收率在95.1%~104.5%之间,Ni的回收率在97.0%~103.5%之间以及Se的回收率在95.9%~104.6%之间。所有元素测定结果的相对标准偏差均小于5.00%。方法简便、快速、灵敏度高、准确性好、可多元素同时测定,且对环境污染小。  相似文献   

18.
19.
A broad elemental profile incorporating 54 elements (Li, Be, B, Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Mo, Pd, Ag, Cd, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Tm, Yb, Re, Ir, Pt, Au, Hg, Tl, Pb, Bi and U) in combination with δ(2) H, δ(13) C, δ(15) N and δ(18) O was used to characterise the composition of 62 green arabica (Coffea arabica) and robusta (Coffea canephora) coffee beans grown in South and Central America, Africa and Asia, the four most internationally renowned areas of production. The δ(2) H, Mg, Fe, Co and Ni content made it possible to correctly assign 95% of green coffee beans to the appropriate variety. Canonical discriminant analysis, performed using δ(13) C, δ(15) N, δ(18) O, Li, Mg, P, K, Mn, Co, Cu, Se, Y, Mo, Cd, La and Ce correctly traced the origin of 98% of coffee beans. Copyright ? 2012 John Wiley & Sons, Ltd.  相似文献   

20.
选取对人体有重要作用的三种糖类化合物,采用高分辨率太赫兹时域光谱系统与傅里叶变换红外光谱系统,在较宽的频谱范围内,对样品进行测谱分析;实验发现无水葡萄糖在1.10,1.30,1.45,1.79,1.88,1.97,2.08,2.40,2.55,2.70,2.84 ,2.96,3.24,3.64和4.23 THz频率处存在特征吸收,无水果糖在1.09,1.33,1.65,2.14,2.62,2.97,3.24,4.75,6.97,7.35,7.98,8.36,9.16,9.32,9.53和9.73 THz频率处存在特征吸收,无水半乳糖在2.21,2.33,2.70,2.82,3.17,3.42,3.93,4.51,5.07,5.96,6.60,6.91,8.03,8.71和9.01 THz频率处存在特征吸收。对掺杂不同比例葡萄糖、果糖、半乳糖与聚乙烯样品的实验结果做定量分析,发现在测得的上述特征吸收频率处,随化合物样品质量分数的增加,样品的吸收系数或吸光度呈线性递增。实验进一步得到无水葡萄糖与无水果糖在2.96 THz存在共同的特征吸收,无水葡萄糖与无水半乳糖在2.33,2.70和2.82 THz三处存在共同的特征吸收,无水果糖与无水半乳糖在8.00 THz处存在共同的特征吸收,而无水葡萄糖、果糖、半乳糖三者在3.20 THz处存在共同的特征吸收。三种化合物具有相同的分子式,所以三者都具有的3.20 THz特征吸收频率主要源于分子内相互作用,反应同分异构体相同的化学键或者基团。三者特征吸收频率的差异主要源于分子结构以及分子间相互作用的不同,代表同分异构体结构以及分子间振动模式的差异。通过分析三种糖类样品的实验测量结果,预测了葡萄糖在4.70,5.30,5.60,5.98,7.03,7.85,8.26,8.71和9.01 THz处存在特征吸收。基于密度泛函理论,采用CASTEP量子化学计算软件对三种化合物进行理论模拟,对样品在THz波段的特征吸收进行指认,计算得到的结果与实验结果吻合,这表明了CASTEP晶体模拟软件在化合物的THz光谱模拟方面应用的可行性。  相似文献   

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