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排序方式: 共有6545条查询结果,搜索用时 15 毫秒
991.
A new method for biochemical oxygen demand (BOD) determination, which combines the series piezoelectric quartz crystal (SPQC) technique with the growth of a microorganism is presented in this paper. This method needs no immobilization of bacteria and is simple and convenient. When a calibration technique was used for BOD analysis, the detection time was 2.5 h at 37°C. There was a good linear relationship between the frequency shift and BOD value in the range 2.2–11 mg/L and the regression equation was ΔF = 64.10 + 11.23[BOD]. The proposed method was compared with the conventional BOD5 method. This method was more rapid than the BOD5 method and the results obtained by the former were in good agreement with those obtained by the latter. The experimental conditions are also discussed in detail. 相似文献
992.
Y. -S. Wang X. -F. Tan C. -H. Shen B. -R. Bao 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(2):683-686
N,N,N',N'-Tetrabutyladipicamide (TBAA) was used for the extraction of nitric acid and uranyl(II) ion from nitric acid media
into toluene. The effects of nitric acid, uranyl(II) ion, and extractant concentration, temperature and back extraction on
the distribution coefficient of uranyl(II) ion have been studied. The main adduct of TBAA and HNO3 is TBAA·HNO3 in 1.0 mol/l nitric acid solution. The 1:2:2 complex of uranyl(II) ion, nitrate ion and TBAA as extracted species is further
confirmed by IR spectra of the extraction of uranyl(II) ion with TBAA. The values of the thermodynamic parameters have also
been calculated. 相似文献
993.
Yang-Xin Yu Tie-Zhu Bao Guang-Hua Gao Yi-Gui Li 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(2):373-377
In order to obtain the exact information of atomic number density in the ternary system of HNO3−UO2(NO3)2−H2O, the densities were measured with an Anton-Paar DMA60/602 digital density meter thermostated at 298.15±0.01 K. The apparent
molal volumes for the systems were calculated from the experimental data. The present measured apparent molar volumes have
been fitted to the Pitzer ion-interaction model, which provides an adequate representation of the experimental data for mixed
aqueous electrolyte solutions up to 6.2 mol/kg ionic strength. This fit yields θ
V
, and ψ
V
, which are the first derivatives with respect to pressure of the mixing interaction parameters for the excess free energy.
With the mixing parameters θ
V
, and ψ
V
, the densities and apparent molar volumes of the ternary system studied in this work can be calculated with good accuracy,
as shown by the standard deviations. 相似文献
994.
995.
Based on the phase-space generating functionalof the Green function, the canonical Ward identities(CWI) under local, nonlocal, and global transformationsin phase space for a system with a regular and singular Lagrangian have been derived. Therelation of global canonical symmetries to conservationlaws at the quantum level is presented. The advantage ofthis formulation is that one does not need to carry out the integration over canonicalmomenta in a phase-space path (functional) integral asin the traditional treatment in configuration space. Ingeneral, the connection between global canonicalsymmetries and conservation laws in classical theories isno longer preserved in quantum theories. Applications ofour formulation to the non-Abelian Chern-Simons (CS)theory are given, and new forms for CS gauge-ghost field proper vertices and the quantal conservedangular momentum of this system are obtained; thisangular momentum differs from the classical one in thatone needs to take into account the contribution of angular momenta of ghost fields. 相似文献
996.
Reactions of trialkyltin oxides with 2‐, 3‐, and 4‐pyridinecarboxylic acids in 1:1 stoichiometry yield 10 corressponding trialkyltin esters R3SnO2CC5H4N. All compounds are characterized by elemental analysis, IR, 1H, 113C, and 119Sn NMR. The crystal structure of tributyltin ester of 2‐pyridinecarboxylic acid is determined by single crystal X‐ray diffraction. In this compound, the tin atom is rendered five‐coordinate in a trigonal bipyramidal structure by coordinating with 2‐pyridinecarboxylate group. The resulting structure is a linear polymer containing Sn O bonds (0.2278(5) and 0.2308(6) nm). © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:524–529, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20057 相似文献
997.
采用扫描电子显微镜、X-光衍射分析和高真空苯吸附量的测定等方法,研究了在一定的化学环境下沸石分子筛的介稳状态;探讨了不同转晶条件对沸石重新晶化的影响;分别研究了在Y型、AG4型或Ω型沸石的合成条件下,加入其它型号的沸石转变为Y型、AG4或Ω型沸石的过程;并研完了在Y型沸石合成的化学环境下,A型沸石向Y型沸石转变的过程,并探讨其机理。 相似文献
998.
THE OPTICAL THEOREM AND A COMPLETE SET OF A MANY BODY SYSTEM LABELLED BY DIFFERENT CHANNEL STATES
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Bao Cheng-guang 《中国物理C(英文版)》1980,4(5):623-625
The asymptotic completeness is discussed by using optical theorem. 相似文献
999.
利用微波分光仪测量介质板的微波吸收系数,考虑了接收器和介抽板对微波的反射影响,沿波传播方向移动介质板的位置来测量同波强度的极大值和极小值,以它们的平均值作为透射波的强度。还考虑了介质板两个界面的反射对入射波强度的影响。 相似文献
1000.