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991.
8-羟基喹啉纤维分离富集-ICP-AES同时测定多种痕量稀土元素郭伊荇,刘春明,赵晓亮,王为玲(东北师范大学测试中心,长春,130024)关键词8-羟基喹啉纤维滤纸片,稀土元素,电感耦合等离子体原子发射光谱地球化学样品中稀土元素的测定主要采用离子交换...  相似文献   
992.
THEAPPLICATIONOFTHEVARIATIONALPRINCIPLEINTHECONSTRAINEDCONTROLSYSTEMDengZi-chen(邓子辰)(NorthwesternPolytechnicalUniversityXi'an...  相似文献   
993.
A comprehensive approach to the mineral composition of black teas of different origins was studied using the Flame Atomic Absorption Spectrometry (FAAS) method, supported by chemometric tools including Principal Component Analysis PCA) and Classification and Regression Trees (CART). Significant differences between the teas from seven countries (Japan, Nepal, Kenya, Iran, Sri Lanka, India, and China) were shown. K was the main element determined in all teas, with an average concentration of 11,649 mg/kg, followed by Ca, Mg and Mn. In general, regarding all investigated black teas, the element content was ranked in the following order: K > Ca > Mg > Mn > Fe > Na > Zn > Cu. The applied chemometric methods allowed us to recognize black tea clusters based on their mineral composition and place of cultivation, and allowed us to find correlations between particular elements in black teas. The performed analyses revealed interesting correlations between the concentration of various elements in black teas: K was negatively correlated with Na, Fe, Mn and Cu; K was positively correlated with the content of Ca and Mg. Significant positive correlations between Mn and Fe and Mn and Zn in the studied black tea samples were also revealed. It was shown that mineral composition may be a significant factor regarding the origin of the black tea, not only considering the country, but also the region or province.  相似文献   
994.
本文把三值闭运算拓广而引人三值符合运算,并提出了一种TTL三值“符合非”门的电路设计  相似文献   
995.
Singer,I.给出了C[a,b]和 L~p[a,b](1≤p< ∞)上线性子空间G的点g_0是点x的最佳逼近元的特征,本文进一步讨论在Orlicz空间上最佳逼近元的特征.文中的术语和记号见[1],[2].设M(·)和N(·)是满足△_2-条件的,互余的N-函数,相应的导数p(·)连续且严格单调增加.这时,M(·)和N(·)的图形不含直线段,所以,根据吴从炘的定理,以Luxemburg范数||·||(m)为范数的Orlicz空间L_(M)~*[a,b]是严格凸的,L_N~*[a,b]也是严格凸的.此外,易见在上述条件下,L_(M)~*的对偶是L_N~*且是自反的,因此,L_(M)~*也是光滑的.  相似文献   
996.
Object “Shelter” (known world-wide as the Sarcophagus) is a source of very high radiological and nuclear hazard. Transfer of the Sarcophagus into an ecologically safe site is a task not only for Ukraine but also for the world community. A composite approach to maintenance of radiation and nuclear safety of the Sarcophagus applying spectrometric methods using solid state nuclear track detectors (SSNTD) is suggested in this paper. The aspects are: (1) monitoring of transuranium element inhalation intake to a human body of nuclear workers; (2) neutron flux evaluation in some premises of the Sarcophagus; (3) fuel hot particle detection in air of working zones; (4) radon and thoron simultaneous measurements.  相似文献   
997.
卓尚军  陶光仪  殷之文  吉昂 《化学学报》1999,57(12):1348-1351
探讨了X射线荧光光谱定量分析中超轻元素的处理方法。在用deJongh-Norrish方程进行定量分析时,对通常不能用X射线荧光光谱直接测定的超轻元素作为消去组分处理以计算理论α系数,然后再以100%减去测量组分和已知组分浓度总和的方法来获得较为准确的分析结果。用此法分析了铌酸钾锂晶体中的Li~2O和两种含硼玻璃中的B~2O~3,分别得到了与等离子体发射光谱法和化学滴定法相符的结果,其中B~2O~3的结果优于文献报道的散射系数法和直接测定法的结果。  相似文献   
998.
GENERALIZED DIFFERENCE METHODS ON ARBITRARY QUADRILATERAL NETWORKS   总被引:14,自引:0,他引:14  
1.IntroductionConsidertheboundaryvalueproblemofthePoissonequationwherefiisaconvexpolygonregon;r~OfftheboundaryofOandf(x,y)aknownfunctiononfi.Thegeneralizeddifferencemethodsonquadrilateralnetworksforellipticequationsareproposedin[11],'wheretheconverge...  相似文献   
999.
Boxma  O.J.  Cohen  J.W. 《Queueing Systems》1999,33(1-3):177-204
We consider a GI/G/1 queue in which the service time distribution and/or the interarrival time distribution has a heavy tail, i.e., a tail behaviour like t −ν with 1 < ν ⩽ 2 , so that the mean is finite but the variance is infinite. We prove a heavy-traffic limit theorem for the distribution of the stationary actual waiting time W. If the tail of the service time distribution is heavier than that of the interarrival time distribution, and the traffic load a → 1, then W, multiplied by an appropriate ‘coefficient of contraction’ that is a function of a, converges in distribution to the Kovalenko distribution. If the tail of the interarrival time distribution is heavier than that of the service time distribution, and the traffic load a → 1, then W, multiplied by another appropriate ‘coefficient of contraction’ that is a function of a, converges in distribution to the negative exponential distribution. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
1000.
Using the topological degree and the concept of exceptional family of elements for a continuous function, we prove a very general existence theorem for the nonlinear complementarity problem. This result is an alternative theorem. A generalization of Karamardian's condition and the asymptotic monotonicity are also introduced. Several applications of the main results are presented.  相似文献   
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